WorldWideScience

Sample records for thick frc composite

  1. Preparasi Minimal pada Pembuatan Gigi Tiruan Cekat dengan Fiber Reinforced Composite (FRC

    Directory of Open Access Journals (Sweden)

    Aditya Ayat Santiko

    2016-11-01

    Full Text Available Dalam praktek sering kali dokter gigi dihadapkan pada pasien yang kehilangan gigi anterior dan ingin segera dibuatkan gigi tiruan karena alasan estetik. Gigi tiruan yang dibuat bisa berupa gigi tiruan sebagian lepasan (GTSL atau gigi tiruan cekat (GTC. Pada GTSL, adanya plat pada palatum menyebabkan rasa tidak nyaman, selain itu pasien setiap kali harus buka pasang gigi tiruan kembali sehingga cukup merepotkan. Oleh karena itu pada umumnya pasien ingin dibuatkan GTC dan hal ini memang sesuai dengan indikasi GTC. Hal yang menjadi pertimbangan pada pembuatan GTC adalah pengasahan permukaan gigi secara keseluruhan bila akan dibuat desain full crown. Pada perkembangan desain GTC ada desain yang disebut resin bonded bridge atau adhesive bridge yaitu GTC yang dibuat pada gigi abutment yang dipreparasi minimal pada bagian palatal saja dan dilekatkan secara mikromekanikal antara retainer sayap logam dan gigi yang telah dipreparasi. Pasien wan ita usia 22 tahun datang ke klinik Prostodonsia RSGM Prof Soedomo UGM karena kehilangan gigi insisif sentral kiri atas. Pada kasus ini dilakukan pembuatan GTC dengan bahan fiber reinforced composite (FRC. Pembuatan bridge dengan bahan FRC dapat dilakukan secara langsung dan tidak langsung. Pada makalah ini akan dibahas pembuatan bridge FRC secara tidak langsung yaitu dengan menggunakan gigi artlfisial komposit. Hasil menunjukkan estetis yang baik, kontrol setelah 2 bulan tidak ada perubahan warna dan pasien merasa puas dengan penampilannya, jaringan gingiva di sekitarnya normal.

  2. PERFORMANCE OF RC AND FRC WALL PANELS REINFORCED WITH MILD STEEL AND GFRP COMPOSITES IN BLAST EVENTS

    Energy Technology Data Exchange (ETDEWEB)

    Timothy Garfield; William D. Richins; Thomas K. Larson; Chris P. Pantelides; James E. Blakeley

    2011-06-01

    The structural integrity of reinforced concrete structures in blast events is important for critical facilities. This paper presents experimental data generated for calibrating detailed finite element models that predict the performance of reinforced concrete wall panels with a wide range of construction details under blast loading. The test specimens were 1.2 m square wall panels constructed using Normal Weight Concrete (NWC) or Fiber Reinforced Concrete (FRC). FRC consists of macro-synthetic fibers dispersed in NWC. Five types of panels were tested: NWC panels with steel bar reinforcement (Type A); FRC panels without additional reinforcement (Type B); FRC panels with steel bar reinforcement (Type C); NWC panels with glass fiber reinforced polymer (GFRP) bar reinforcement (Type D); and NWC panels reinforced with steel bar reinforcement and external bidirectional GFRP overlays on both faces (Type E). An additional three Type C panels were used as control specimens (CON). Each panel type was constructed with three thicknesses: 152 mm, 254 mm, and 356 mm. The panels were instrumented with strain gauges, and accelerometers; in addition, pressure sensors and high speed videos were employed during the blast events. Panel types C and E had the best performance, whereas panel type B did not perform well. Preliminary dynamic simulations show crack patterns similar to the experimental results.

  3. Effect of length and diameter of fiber reinforced composite post (FRC on fracture resistance of remaining tooth structure

    Directory of Open Access Journals (Sweden)

    Mahdiyeh seifi

    2013-03-01

    Full Text Available Introduction: Post and core has been considered for endodontically treated tooth, especially in cases with severe damage crowns. Recently fiber reinforced composite posts (FRC post have been used in the treatment of endodontically treated teeth. Because the length and diameter of posts are effective in stress distribution, the purpose of this study is to evaluate the effect of length and diameter of FRC post on fracture resistance. Methods: In this experimental study, 36 glass fiber posts with combination of 7mm, 9mm, and 12mm length and 1.1mm, 1.3mm and 1.5mm diameter were divided into 9 groups of 4. These posts were cemented in root canals by Panavia. Samples were tested with 45° compressive forces for the evaluation of fracture resistance. Datas were analyzed using SPSS soft ware and One- way and Two-way ANOVA analyses. Results: Fracture resistance did not increase significantly with the effect of length and diameter simultaneously (P=0.85. Samples with 12mm length and 1.5mm diameter had the greatest fracture resistance (1023/33N±239/22. The minimum fracture resistance had occurred in post with 7mm length and 1.5mm diameter (503/13N ±69/18. Fracture resistance increased significantly by increasing the length and the same diameter. Conclusion: It can be concluded that fracture resistance is affected by the length and not the diameter of FRC post.

  4. FRC : fire retardant clothing

    Energy Technology Data Exchange (ETDEWEB)

    Denhard, G. [Manitoba Hydro, Winnipeg, MB (Canada)

    2006-07-01

    This presentation provided details of the Manitoba Hydro's flame resistant clothing (FRC) program, which was devised after 2 separate incidents in 1998 where clothing contributed to the extent of personnel injuries. The FRC program became corporate-wide in 2005, after the utility's FRC steering committee completed an investigation of the relevant industry standards and regulatory requirements needed to develop an FRC implementation plan. Standards used to prepare the FRC policy included the standard performance specification for textile materials; the standard test method for determining arc thermal performance values of materials for clothing; the standard specification for arc and flame resistant rainwear; and the Occupational Safety and Health Administration (OSHA) 1910.269 regulation, which states that employers shall ensure that employees are not wearing clothing that could increase the extent of potential injuries. A consultation of the utility's corporate policies included the uniform, clothing and equipment policy, and the corporate safety and occupational health rule. As a result of the FRC program, Manitoba Hydro now provides personal protective clothing and equipment; flame resistant clothing; and clothing for regular exposure to certain conditions. FRC must be worn when entering energized AC or DC switchyards; operational maintenance or construction sites where a clothing ignition hazard exists; and in any area designated as requiring workers to wear FRC. The program was designed using a risk-based approach, and employees were divided into the following 4 groups: groups requiring that all layers of their clothing be FRC; groups requiring FRC as the outer layer of their clothing; groups required to wear FRC only when entering certain work sites; and special case personnel dealt with on a case-by-case basis. Implementation costs of the program were estimated at $2.3 million, with a $500,000 annual cost. However, annual costs for 2005 were

  5. Intelligent processing for thick composites

    Science.gov (United States)

    Shin, Daniel Dong-Ok

    2000-10-01

    Manufacturing thick composite parts are associated with adverse curing conditions such as large in-plane temperature gradient and exotherms. The condition is further aggravated because the manufacturer's cycle and the existing cure control systems do not adequately counter such affects. In response, the forecast-based thermal control system is developed to have better cure control for thick composites. Accurate cure kinetic model is crucial for correctly identifying the amount of heat generated for composite process simulation. A new technique for identifying cure parameters for Hercules AS4/3502 prepreg is presented by normalizing the DSC data. The cure kinetics is based on an autocatalytic model for the proposed method, which uses dynamic and isothermal DSC data to determine its parameters. Existing models are also used to determine kinetic parameters but rendered inadequate because of the material's temperature dependent final degree of cure. The model predictions determined from the new technique showed good agreement to both isothermal and dynamic DSC data. The final degree of cure was also in good agreement with experimental data. A realistic cure simulation model including bleeder ply analysis and compaction is validated with Hercules AS4/3501-6 based laminates. The nonsymmetrical temperature distribution resulting from the presence of bleeder plies agreed well to the model prediction. Some of the discrepancies in the predicted compaction behavior were attributed to inaccurate viscosity and permeability models. The temperature prediction was quite good for the 3cm laminate. The validated process simulation model along with cure kinetics model for AS4/3502 prepreg were integrated into the thermal control system. The 3cm Hercules AS4/3501-6 and AS4/3502 laminate were fabricated. The resulting cure cycles satisfied all imposed requirements by minimizing exotherms and temperature gradient. Although the duration of the cure cycles increased, such phenomena was

  6. FRC collisionless resistivity

    International Nuclear Information System (INIS)

    Tajima, T.; Horton, W.

    1990-01-01

    Ions in the field reversed configuration (FRC) exhibit stochastic orbits due to the field null and the curvature of poloidal field lines. Velocity correlations of these particles decay in a power law fashion t -m where 1 ≤ m ≤ 2. This decay of the single particle correlation function is characteristic of the long tail correlations of strongly chaotic or nonlinear systems found in other problems of statistical physics. This decay of correlations gives rise to a collisionless resistivity that can far exceed the collisional resistivity in an FRC plasma. The finite correlation τ c of a single particle limits the acceleration in the electric field producing the finite resistivity. Maxwellian test particle distributions are integrated to find the measure of the set of stochastic ions that contribute to the collisionless resistivity. The computed conductivity is proportional to the square root of the characteristic ion gyroradius in both simulation and theory

  7. Effect of different composite core materials on fracture resistance of endodontically treated teeth restored with FRC posts

    OpenAIRE

    PANITIWAT, Prapaporn; SALIMEE, Prarom

    2017-01-01

    Abstract Objective This study evaluated the fracture resistance of endodontically treated teeth restored with fiber reinforced composite posts, using three resin composite core build-up materials, (Clearfil Photo Core (CPC), MultiCore Flow (MCF), and LuxaCore Z-Dual (LCZ)), and a nanohybrid composite, (Tetric N-Ceram (TNC)). Material and Methods Forty endodontically treated lower first premolars were restored with quartz fiber posts (D.T. Light-Post) cemented with resin cement (Panavia F2...

  8. Development of Fracture Energy of FRC Materials. Freeze-Thaw Resistance of FRC Materials

    DEFF Research Database (Denmark)

    Stoklund Larsen, E.

    During the past four years research has been carried out at the Danish Building Research Institute on different aspects of the long term performance of fibre reinforced cementitious composites (FRC) exposed to climate stresses. Some of the most important results have been brought together in this...

  9. Effect of different composite core materials on fracture resistance of endodontically treated teeth restored with FRC posts.

    Science.gov (United States)

    Panitiwat, Prapaporn; Salimee, Prarom

    2017-01-01

    This study evaluated the fracture resistance of endodontically treated teeth restored with fiber reinforced composite posts, using three resin composite core build-up materials, (Clearfil Photo Core (CPC), MultiCore Flow (MCF), and LuxaCore Z-Dual (LCZ)), and a nanohybrid composite, (Tetric N-Ceram (TNC)). Forty endodontically treated lower first premolars were restored with quartz fiber posts (D.T. Light-Post) cemented with resin cement (Panavia F2.0). Samples were randomly divided into four groups (n=10). Each group was built-up with one of the four core materials following its manufacturers' instructions. The teeth were embedded in acrylic resin blocks. Nickel-Chromium crowns were fixed on the specimens with resin cement. The fracture resistance was determined using a universal testing machine with a crosshead speed of 1 mm/min at 1350 to the tooth axis until failure occurred. All core materials used in the study were subjected to test for the flexural modulus according to ISO 4049:2009. One-way ANOVA and Bonferroni multiple comparisons test indicated that the fracture resistance was higher in the groups with CPC and MCF, which presented no statistically significant difference (p>0.05), but was significantly higher than in those with LCZ and TNC (paligned with the same tendency of fracture loads. Among the cores used in this study, the composite core with high filler content tended to enhance fracture thresholds of teeth restored with fiber posts more than others.

  10. Compressive strength of thick composite panels

    DEFF Research Database (Denmark)

    Branner, Kim; Berring, Peter

    2011-01-01

    The aim of this study is to investigate how much the compressive strength of thick composite panels is reduced due to delaminations and to investigate under which conditions a delamination will grow. Understanding of this is essential in order to move forward the design limits used in the structu......The aim of this study is to investigate how much the compressive strength of thick composite panels is reduced due to delaminations and to investigate under which conditions a delamination will grow. Understanding of this is essential in order to move forward the design limits used...

  11. Effect of different composite core materials on fracture resistance of endodontically treated teeth restored with FRC posts

    Directory of Open Access Journals (Sweden)

    Prapaporn PANITIWAT

    Full Text Available Abstract Objective This study evaluated the fracture resistance of endodontically treated teeth restored with fiber reinforced composite posts, using three resin composite core build-up materials, (Clearfil Photo Core (CPC, MultiCore Flow (MCF, and LuxaCore Z-Dual (LCZ, and a nanohybrid composite, (Tetric N-Ceram (TNC. Material and Methods Forty endodontically treated lower first premolars were restored with quartz fiber posts (D.T. Light-Post cemented with resin cement (Panavia F2.0. Samples were randomly divided into four groups (n=10. Each group was built-up with one of the four core materials following its manufacturers’ instructions. The teeth were embedded in acrylic resin blocks. Nickel-Chromium crowns were fixed on the specimens with resin cement. The fracture resistance was determined using a universal testing machine with a crosshead speed of 1 mm/min at 1350 to the tooth axis until failure occurred. All core materials used in the study were subjected to test for the flexural modulus according to ISO 4049:2009. Results One-way ANOVA and Bonferroni multiple comparisons test indicated that the fracture resistance was higher in the groups with CPC and MCF, which presented no statistically significant difference (p>0.05, but was significantly higher than in those with LCZ and TNC (p<0.05. In terms of the flexural modulus, the ranking from the highest values of the materials was aligned with the same tendency of fracture loads. Conclusion Among the cores used in this study, the composite core with high filler content tended to enhance fracture thresholds of teeth restored with fiber posts more than others.

  12. Process simulations for manufacturing of thick composites

    Science.gov (United States)

    Kempner, Evan A.

    The availability of manufacturing simulations for composites can significantly reduce the costs associated with process development. Simulations provide a tool for evaluating the effect of processing conditions on the quality of parts produced without requiring numerous experiments. This is especially significant in parts that have troublesome features such as large thickness. The development of simulations for thick walled composites has been approached by examining the mechanics of resin flow and fiber deformation during processing, applying these evaluations to develop simulations, and evaluating the simulation with experimental results. A unified analysis is developed to describe the three-dimensional resin flow and fiber preform deformation during processing regardless of the manufacturing process used. It is shown how the generic governing evaluations in the unified analysis can be applied to autoclave molding, compression molding, pultrusion, filament winding, and resin transfer molding. A comparison is provided with earlier models derived individually for these processes. The evaluations described for autoclave curing were used to produce a one-dimensional cure simulation for autoclave curing of thick composites. The simulation consists of an analysis for heat transfer and resin flow in the composite as well as bleeder plies used to absorb resin removed from the part. Experiments were performed in a hot press to approximate curing in an autoclave. Graphite/epoxy laminates of 3 cm and 5 cm thickness were cured while monitoring temperatures at several points inside the laminate and thickness. The simulation predicted temperatures fairly closely, but difficulties were encountered in correlation of thickness results. This simulation was also used to study the effects of prepreg aging on processing of thick composites. An investigation was also performed on filament winding with prepreg tow. Cylinders were wound of approximately 12 mm thickness with pressure

  13. Hybrid FRC under repeated loading

    International Nuclear Information System (INIS)

    Komlos, K.; Babal, B.; Nuernbergerova, T.

    1993-01-01

    Fibre reinforced concretes (FRC) containing several volume fractions in different ratios of two types of fibres - polypropylene and steel, were tested under repeated loading. Mechanical properties of specimens - cubes 150/150/150 mm (for compressive strength), prisms 100/100/400 (for flexural strength), short cylinders 150/60 mm (for impact strength) have been experimentally investigated before and after cyclic loading at the age of 28 days curing time. Mix proportions were designed after DIN 1045 with max. aggregate size 8 mm and grading curve B 8. Portland Cement PC 400 in the amount of 450 kg. m -3 was applied and W/C ratio 0.55. Workability of mixes was measured by Vebe method and regulated by plasticizing admixture Ligoplast Na. Maximum hybrid fibre volume fraction (polypropylene + steel) was 1.0%. Dynamic forces generated in Schenck testing machine with frequency 16 Hz had sinusoidal wave form varying between 0.7 and 0.1 of static mechanical characteristics. The number of cycles in all tests was 10 5 . The residual MOR at static four point bending test and working diagram force-deflection was carried out as well. The impact properties after repeated loading in compression were tested by means of falling weight test. Relationships between composition of fibre composites with different combination of polypropylene (0.2, 0.3, 0.5% by volume) and steel (0.5, 0.7, and 0.8% by volume) fibre content were obtained and technological properties of mixes as well. (author)

  14. Temperature distribution of thick thermoset composites

    Science.gov (United States)

    Guo, Zhan-Sheng; Du, Shanyi; Zhang, Boming

    2004-05-01

    The development of temperature distribution of thick polymeric matrix laminates during an autoclave vacuum bag process was measured and compared with numerically calculated results. The finite element formulation of the transient heat transfer problem was carried out for polymeric matrix composite materials from the heat transfer differential equations including internal heat generation produced by exothermic chemical reactions. Software based on the general finite element software package was developed for numerical simulation of the entire composite process. From the experimental and numerical results, it was found that the measured temperature profiles were in good agreement with the numerical ones, and conventional cure cycles recommended by prepreg manufacturers for thin laminates should be modified to prevent temperature overshoot.

  15. Modification of the magnetic field structure in the vicinity of the x-points by the strong mirror field for a field-reversed configuration (FRC) with the Thick Edge-Layer plasma

    International Nuclear Information System (INIS)

    Suzuki, Yukihisa; Okada, Shigefumi; Goto, Seiichi

    2003-01-01

    Modification of the magnetic field structure in the vicinity of the x-points and changes of the separatrix shape are investigated under the pressure effects due to an edge-layer plasma together with a mirror field by the two-dimensional (2-D) MHD equilibrium solutions of field-reversed configuration (FRC) obtained from the Grad-Shafranov equation. To explore the coupling pressure effects caused by edge-layer plasma and mirror field, the equilibrium calculations are performed by the combinations of several values of mirror ratio (R m ) and of edge-layer width (δ), respectively. A summary of results for present study is as follows. In the condition of weak mirror field (1.0 m m > 1.6, ψ=0 surface never opens up for any δ. These original results make it clear that large magnetic curvature produced by the strong mirror field enhances the magnetic stress around the x-point, so that the ends of FRC are effectively sustained by this enhanced magnetic stress, which counteracts the edge-layer plasma pressure effect. (author)

  16. FRC studies on FRX-B

    International Nuclear Information System (INIS)

    Armstrong, W.T.; Cochrane, J.C.; Lipson, J.; Linford, R.K.; McKenna, K.F.; Sgro, A.G.; Sherwood, E.G.; Siemon, R.E.; Tuszewski, M.

    1980-01-01

    Recent experimental studies of Field-Reversed Configurations (FRC) on the FRX-B device have included (1) characterization of FRC formation with regard to loss of bias flux, (2) examination of FRC equilibria through separatrix profiles, (3) formation of FRC's with different end-mirror configurations, and (4) extension of FRC parameter range. Studies on loss of bias flux during the pre-ionization (PI) phase of FRC formation are presented in another paper dedicated solely to PI considerations. Loss of bias flux during the reversal phase of FRC formation is reviewed in the first section of this paper. Use of barrier fields during the reversal phase to enhance trapping of bias flux is included in the third section of this paper. In addition to barrier field studies, results from different mirror configurations are also discussed in the third section. A critical diagnostic for interpretation of the results from the different machine modifications is the excluded-flux probe array. Analysis of excluded-flux measurements to obtain the FRC separatrix profile is described in the second section. Finally, preliminary results of FRX-B operation in an extended range of plasma parameters is briefly discussed in the fourth section

  17. FRC studies on FRX-B

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, W.T.; Cochrane, J.C.; Lipson, J.; Linford, R.K.; McKenna, K.F.; Sgro, A.G.; Sherwood, E.G.; Siemon, R.E.; Tuszewski, M.

    1980-01-01

    Recent experimental studies of Field-Reversed Configurations (FRC) on the FRX-B device have included (1) characterization of FRC formation with regard to loss of bias flux, (2) examination of FRC equilibria through separatrix profiles, (3) formation of FRC's with different end-mirror configurations, and (4) extension of FRC parameter range. Studies on loss of bias flux during the pre-ionization (PI) phase of FRC formation are presented in another paper dedicated solely to PI considerations. Loss of bias flux during the reversal phase of FRC formation is reviewed in the first section of this paper. Use of barrier fields during the reversal phase to enhance trapping of bias flux is included in the third section of this paper. In addition to barrier field studies, results from different mirror configurations are also discussed in the third section. A critical diagnostic for interpretation of the results from the different machine modifications is the excluded-flux probe array. Analysis of excluded-flux measurements to obtain the FRC separatrix profile is described in the second section. Finally, preliminary results of FRX-B operation in an extended range of plasma parameters is briefly discussed in the fourth section.

  18. Thickness filters for gradient based multi-material and thickness optimization of laminated composite structures

    DEFF Research Database (Denmark)

    Sørensen, Rene; Lund, Erik

    2015-01-01

    This paper presents a new gradient based method for performing discrete material and thickness optimization of laminated composite structures. The novelty in the new method lies in the application of so-called casting constraints, or thickness filters in this context, to control the thickness...... variation throughout the laminate. The filters replace the layerwise density variables with a single continuous through-the-thickness design variable. Consequently, the filters eliminate the need for having explicit constraints for preventing intermediate void through the thickness of the laminate....... Therefore, the filters reduce both the number of constraints and design variables in the optimization problem. Based upon a continuous approximation of a unit step function, the thickness filters are capable of projecting discrete 0/1 values to the underlying layerwise or ”physical” density variables which...

  19. Manufacturing of composite parts reinforced through-thickness by tufting

    OpenAIRE

    Dell'Anno, G.; Treiber, J. W G; Partridge, Ivana K

    2016-01-01

    The paper aims at providing practical guidelines for the manufacture of composite parts reinforced by tufting. The need for through-thickness reinforcement of high performance carbon fibre composite structures is reviewed and various options are presented. The tufting process is described in detail and relevant aspects of the technology are analysed such as: equipment configuration and setup, latest advances in tooling, thread selection, preform supporting systems and choice of ancillary mate...

  20. The FAST (FRC Acceleration Space Thruster) Experiment

    Science.gov (United States)

    Martin, Adam; Eskridge, R.; Lee, M.; Richeson, J.; Smith, J.; Thio, Y. C. F.; Slough, J.; Rodgers, Stephen L. (Technical Monitor)

    2001-01-01

    The Field Reverse Configuration (FRC) is a magnetized plasmoid that has been developed for use in magnetic confinement fusion. Several of its properties suggest that it may also be useful as a thruster for in-space propulsion. The FRC is a compact toroid that has only poloidal field, and is characterized by a high plasma beta = (P)/(B (sup 2) /2Mu0), the ratio of plasma pressure to magnetic field pressure, so that it makes efficient use of magnetic field to confine a plasma. In an FRC thruster, plasmoids would be repetitively formed and accelerated to high velocity; velocities of = 250 km/s (Isp = 25,000s) have already been achieved in fusion experiments. The FRC is inductively formed and accelerated, and so is not subject to the problem of electrode erosion. As the plasmoid may be accelerated over an extended length, it can in principle be made very efficient. And the achievable jet powers should be scalable to the MW range. A 10 kW thruster experiment - FAST (FRC Acceleration Space Thruster) has just started at the Marshall Space Flight Center. The design of FAST and the status of construction and operation will be presented.

  1. Method for determining thickness and composition of foils

    International Nuclear Information System (INIS)

    Roessiger, V.

    1984-01-01

    Subject of the invention is a radiometric method for simultaneous determination of the thickness or mass per unit area and the chemical composition of foils consisting of two or more components. The method is based on the measurement of the attenuation of several components of a suitable polychromatic radiation

  2. FRC translation into a compression coil

    International Nuclear Information System (INIS)

    Chrien, R.E.

    1985-01-01

    Several features of the problem of FRC translation into a compression coil are considered. First, the magnitude of the guide field is calculated and found to exceed that which would be applied to a flux conserver. Second, energy conservation is applied to FRC translation from a flux conserver into a compression coil. It is found that a significant temperature decrease is required for translation to be energetically possible. The temperature change depends on the external inductance in the compression circuit. An analogous case is that of a compression region composed of a compound magnet; in this case the temperature change depends on the ratio of inner and outer coil radii. Finally, the kinematics of intermediate translation states are calculated using an ''abrupt transition'' model. It is found, in this model, that the FRC must overcome a potential hill during translation, which requires a small initial velocity

  3. Recent results on the FRC transport

    International Nuclear Information System (INIS)

    Tuszewski, M.

    1984-01-01

    Some recent transport studies of field-reversed configurations (FRC) during their equilibrium phase are presented. The FRC confinement times of interest tau/sub N/, tau/sub E/, and tau/ sub phi/ are for particles, energy, and trapped-flux, respectively. An analytical expression for tau/sub N/ based on Lower-Hybrid-Drift (LHD) resistivity is presented. Some progress in assessing the respective contributions of radiation and thermal conduction to tau/sub E/ is given. Finally, the relation tau/sub E/ less than or equal to tau/sub phi/ is discussed

  4. Sustainable Materials Management (SMM) Food Recovery Challenge (FRC) Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — As part of EPA's Food Recovery Challenge (FRC), organizations pledge to improve their sustainable food management practices and report their results. The FRC is part...

  5. Initial ionization stage of FRC formation

    International Nuclear Information System (INIS)

    Commisso, R.J.; Armstrong, W.T.; Cochrane, J.C.; Ekdahl, C.A.; Lipson, J.; Linford, R.K.; Sherwood, E.G.; Siemon, R.E.; Tuszewski, M.

    1980-01-01

    A Field-Reversed Configuration (FRC) is a prolate compact torus that is confined by poloidal fields only. Theta-pinch formation of an FRC employs an initial bias field, B 1 , whose direction is opposite to that of the main theta-pinch field. Some fraction of the flux associated with this bias field eventually constitutes the closed-field-line flux of the FRC. Experimental and theoretical evidence suggest that the longest-lived FRC's are obtained when the closed flux is maximized. Because the initial ionization is done in the presence of the bias field, the actual bias flux available at the time of application of the main theta-pinch field depends strongly on the initial ionization, or preionization, technique used. In this paper we report on experiments characterizing the previously used theta-pinch preionization technique that employed a net field (bias plus preionization) null, or zero-crossing, of the axial component of the magnetic field to break down the gas. We also discuss results of experiments designed to develop preionization techniques in which the gas breakdown is not accomplished by a zero-crossing

  6. Initial ionization stage of FRC formation

    Energy Technology Data Exchange (ETDEWEB)

    Commisso, R.J.; Armstrong, W.T.; Cochrane, J.C.; Ekdahl, C.A.; Lipson, J.; Linford, R.K.; Sherwood, E.G.; Siemon, R.E.; Tuszewski, M.

    1980-01-01

    A Field-Reversed Configuration (FRC) is a prolate compact torus that is confined by poloidal fields only. Theta-pinch formation of an FRC employs an initial bias field, B/sub 1/, whose direction is opposite to that of the main theta-pinch field. Some fraction of the flux associated with this bias field eventually constitutes the closed-field-line flux of the FRC. Experimental and theoretical evidence suggest that the longest-lived FRC's are obtained when the closed flux is maximized. Because the initial ionization is done in the presence of the bias field, the actual bias flux available at the time of application of the main theta-pinch field depends strongly on the initial ionization, or preionization, technique used. In this paper we report on experiments characterizing the previously used theta-pinch preionization technique that employed a net field (bias plus preionization) null, or zero-crossing, of the axial component of the magnetic field to break down the gas. We also discuss results of experiments designed to develop preionization techniques in which the gas breakdown is not accomplished by a zero-crossing.

  7. Additional heating experiments of FRC plasmas

    International Nuclear Information System (INIS)

    Okada, S.; Asai, T.; Kodera, F.; Kitano, K.; Suzuki, T.; Yamanaka, K.; Kanki, T.; Inomoto, M.; Yoshimura, S.; Okubo, M.; Sugimoto, S.; Ohi, S.; Goto, S.

    2001-01-01

    Additional heating experiments of neutral beam (NB) injection and application of low frequency wave on a plasma with extremely high averaged beta value of about 90% - a field reversed configuration (FRC) plasma - are carried out on the FRC Injection experiment (FIX) apparatus. These experiments are made possible by translating the FRC plasma produced in a formation region of a theta pinch to a confinement region in order to secure better accessibility to heating facilities and to control plasma density. By appropriate choice of injection geometry and the mirror ratio of the confinement region, the NB with the energy of 14keV and the current of 23A is enabled to be injected into the FRC in the solenoidal confining field of only 0.04-0.05T. Confinement is improved by this experiment. Ion heating is observed by the application of low frequency (80kHz ; about 1/4 of the ion gyro frequency) compressional wave. A shear wave, probably mode converted from the compressional wave, is detected to propagate axially. (author)

  8. Economical Fabrication of Thick-Section Ceramic Matrix Composites

    Science.gov (United States)

    Babcock, Jason; Ramachandran, Gautham; Williams, Brian; Benander, Robert

    2010-01-01

    A method was developed for producing thick-section [>2 in. (approx.5 cm)], continuous fiber-reinforced ceramic matrix composites (CMCs). Ultramet-modified fiber interface coating and melt infiltration processing, developed previously for thin-section components, were used for the fabrication of CMCs that were an order of magnitude greater in thickness [up to 2.5 in. (approx.6.4 cm)]. Melt processing first involves infiltration of a fiber preform with the desired interface coating, and then with carbon to partially densify the preform. A molten refractory metal is then infiltrated and reacts with the excess carbon to form the carbide matrix without damaging the fiber reinforcement. Infiltration occurs from the inside out as the molten metal fills virtually all the available void space. Densification to thick-section components required modification of the conventional process conditions, and the means by which the large amount of molten metal is introduced into the fiber preform. Modification of the low-temperature, ultraviolet-enhanced chemical vapor deposition process used to apply interface coatings to the fiber preform was also required to accommodate the high preform thickness. The thick-section CMC processing developed in this work proved to be invaluable for component development, fabrication, and testing in two complementary efforts. In a project for the Army, involving SiC/SiC blisk development, nominally 0.8 in. thick x 8 in. diameter (approx. 2 cm thick x 20 cm diameter) components were successfully infiltrated. Blisk hubs were machined using diamond-embedded cutting tools and successfully spin-tested. Good ply uniformity and extremely low residual porosity (41 ksi (approx. 283 MPa) flexural strength.

  9. Fatigue qualification of high thickness composite rotor components

    Science.gov (United States)

    Raggi, M.; Mariani, U.; Zaffaroni, G.

    Fatigue qualification aspects of composite rotor components are presented according with the safe life procedure usually applied by helicopter manufacturers. Test activities are identified at three levels of specimen complexity: coupon, structural element and full scale component. Particular attention is given to high thickness laminates qualification as far as environmental exposure is concerned. A practical approach for an accelerated conditioning procedure is described. The application to a main rotor tension link is presented showing the negligible effect of the moisture absorption on its fatigue strength.

  10. FRC translation into a compression coil

    International Nuclear Information System (INIS)

    Chrien, R.E.

    1986-01-01

    The equilibrium and translational kinematics of Field-Reversed Configurations (FRCs) in a cylindrical coil which does not conserve flux are problems that arise in connection with adiabatic compressional heating. In this paper, they consider several features of the problem of FRC translation into a compression coil. First, the magnitude of the guide field is calculated and found to exceed that which would be applied to a flux conserver. Second, energy conservation is applied to FRC translation from a flux conserver into a compression coil. It is found that a significant temperature decrease is required for translation to be energetically possible. The temperature change depends on the external inductance in the compression circuit. An analogous case is that of a compression region composed of a compound magnet; in this case the temperature change depends on the ratio of inner and outer coil radii. Finally, the kinematics of intermediate translation states are calculated using an abrupt transition model. It is found, in this model, that the FRC must overcome a potential hill during translation, which requires a small initial velocity

  11. Fatigue behavior of thick composite single lap joints

    Energy Technology Data Exchange (ETDEWEB)

    Tang, J.H.; Sridhar, I.; Srikanth, N. [Nanyang Technological Univ., Singapore (Singapore)

    2012-07-01

    In consideration of bondline thickness variability, in bonded joints where thick adherend is adopted, relative thick adhesive layer (2-5 mm) is preferable. This paper aims to give some insight in fatigue strength of adhesively bonded structures involving thick adherend coupled with thick adhesive layer. Single lap joints with nominal adherend thickness of 8 mm and two different nominal thicknesses (2.5 mm and 5.5 mm) were made and tested under fatigue loading. The failure mode exhibits always a tendency for interfacial initiation, followed by interlaminar separation. Fatigue strength for higher adhesive thickness is found to be lower. (Author)

  12. Curing of Thick Thermoset Composite Laminates: Multiphysics Modeling and Experiments

    Science.gov (United States)

    Anandan, S.; Dhaliwal, G. S.; Huo, Z.; Chandrashekhara, K.; Apetre, N.; Iyyer, N.

    2017-11-01

    Fiber reinforced polymer composites are used in high-performance aerospace applications as they are resistant to fatigue, corrosion free and possess high specific strength. The mechanical properties of these composite components depend on the degree of cure and residual stresses developed during the curing process. While these parameters are difficult to determine experimentally in large and complex parts, they can be simulated using numerical models in a cost-effective manner. These simulations can be used to develop cure cycles and change processing parameters to obtain high-quality parts. In the current work, a numerical model was built in Comsol MultiPhysics to simulate the cure behavior of a carbon/epoxy prepreg system (IM7/Cycom 5320-1). A thermal spike was observed in thick laminates when the recommended cure cycle was used. The cure cycle was modified to reduce the thermal spike and maintain the degree of cure at the laminate center. A parametric study was performed to evaluate the effect of air flow in the oven, post cure cycles and cure temperatures on the thermal spike and the resultant degree of cure in the laminate.

  13. Theoretical studies of field-reversed configurations (FRC) and experimental study of the FRC during translation

    International Nuclear Information System (INIS)

    Siemon, R.E.; Armstrong, W.T.; Chrien, R.E.

    1985-01-01

    Theoretical studies of FRC stability and transport are summarized. Finite Larmor radius theories are shown to be unreliable for explaining the experimentally observed stability to tilting. Control of the n=2 rotational instability has been demonstrated in two-dimensional hybrid code simulations, and the stability appears to be described within MHD if the nearly square equilibria that result from quadrupole fields are taken into account. Simulations of the lower hybrid drift instability in parameter regimes relevant to experiments show good agreement with a non-local theory of the instability. A 1.5-dimensional transport code shows agreement with the energy confinement time but disagreement with the flux loss time observed in FRX-C. The process of FRC translation in which the plasma is formed, translated into a DC solenoid and trapped by magnetic mirrors, has been studied in the FRX-C/T experiment. Efficient transfer of particles, energy and internal magnetic flux are observed with no enhancement of loss processes over in-situ FRC experiments. The axial velocity of the FRC can be estimated reasonably well with a simple model based on conservation of energy. Internal magnetic field probing during translation shows the expected structure of poloidal field and a complex distribution of generally weak toroidal fields. Measurements of radiated power indicate that radiation is a small fraction of the total plasma power loss (typically 8%). Translation has facilitated scaling studies of confinement over a wider range of parameters than were achieved by in-situ FRX-C experiments. For example, the variable xsub(s), the ratio of the separatrix radius to the metal wall radius, has been increased to about 0.7 by allowing the FRC to expand during translation. In all cases, particle confinement times agree within a factor of two with predictions by models that assume a lower hybrid drift resistivity. However, for the conditions studied there are indications that the experimental

  14. Ultimate pressure capacity assessment of R FRC PCCV based on the tension stiffening tests

    International Nuclear Information System (INIS)

    Hahm, Dae Gi; Choun, Young Sun

    2012-01-01

    The use of fibers in concrete or cement composites can enhance the performance of structural elements. Fibers have been used for a cement mixture to increase the toughness and tensile strength, and to improve the cracking and deformation characteristics. The addition of fibers into concrete can improve the ductility and increase the tensile resistance of concrete structures. Recently, the application of fibers to prestressed concrete containment vessels (PCCVs) has been a major research topic. However, the tensile stiffening behavior of reinforced - fiber reinforced concrete (RFRC) is not fully developed yet especially for specimens using large diameter re bars. In nuclear power plant (NPP) PCCVs, large diameter re bars are applied. Therefore, the tensile stiffening behavior model should be developed to assess ultimate pressure capacity (UPC) of R FRC PCCVs. In this study, we modeled the tensile stiffening behavior of R FRC PCCVs by using recently developed model, and assessed the UPC of R FRC PCCVs. To do this, we performed tension stiffening test of R FRC with large diameter re bar

  15. Ultimate pressure capacity assessment of R FRC PCCV based on the tension stiffening tests

    Energy Technology Data Exchange (ETDEWEB)

    Hahm, Dae Gi; Choun, Young Sun [KAERI, Daejeon (Korea, Republic of)

    2012-10-15

    The use of fibers in concrete or cement composites can enhance the performance of structural elements. Fibers have been used for a cement mixture to increase the toughness and tensile strength, and to improve the cracking and deformation characteristics. The addition of fibers into concrete can improve the ductility and increase the tensile resistance of concrete structures. Recently, the application of fibers to prestressed concrete containment vessels (PCCVs) has been a major research topic. However, the tensile stiffening behavior of reinforced - fiber reinforced concrete (RFRC) is not fully developed yet especially for specimens using large diameter re bars. In nuclear power plant (NPP) PCCVs, large diameter re bars are applied. Therefore, the tensile stiffening behavior model should be developed to assess ultimate pressure capacity (UPC) of R FRC PCCVs. In this study, we modeled the tensile stiffening behavior of R FRC PCCVs by using recently developed model, and assessed the UPC of R FRC PCCVs. To do this, we performed tension stiffening test of R FRC with large diameter re bar.

  16. On Early Age Crack Formation in FRC Slabs

    DEFF Research Database (Denmark)

    Olesen, John Forbes; Stang, Henrik

    1997-01-01

    The problem of early age crack formation in FRC slabs due to restrained temperature and shrinkage deformations, is given an analytical treatment. A model taking into account the ageing properties of the tensile softening curve and the continued development in the temperature and shrinkage...... deformations after crack initiation, is presented. Based on this model a design strategy for FRC slabs is outlined....

  17. Study optoelectronic properties for polymer composite thick film

    Science.gov (United States)

    Jobayr, Mahmood Radhi; Al Razak, Ali Hussein Abd; Mahdi, Shatha H.; Fadhil, Rihab Nassr

    2018-05-01

    Coupling the epoxy with cadmium oxide particles are important for optical properties that may be affected by various mixing proportions. The aim of this experimental study was to evaluate the effect of different mixing proportions on these properties of reinforced epoxy with cadmium oxide particles. The ultrasonic techniques were used to mix and prepared samples of composites. The surfaces topographic of the 50 µm thick reinforced epoxy films were studied using atomic force microscopy (AFM) and microscopy technique (FTIR) Spectroscopy. AFM imaging and quantitative characterization of the films showed that for all samples the root mean square of the surface roughness increases monotonically with increasing the CdO concentrations (from 0% to 15%). The observed effects of CdO concentrations on surface roughness can be explained by two things: the first reason is that the atoms of additives are combined with the original material to form a new compound that is smoother, more homogeneity and smaller in particle size. The second reason is due to high mixing due to ultrasonic mixing. It is clear also, AFM examination of the prepared samples of reinforced epoxy resin shown that topographical contrast and the identification of small structural details critically depend on hardness of epoxy resin, which in turn depended on the ratio of material (CdO) added. We show that the AFM imaging of the films showed that the mean diameter (104.8nm) of films for all of the samples decreased from 135.50 nm to 83.20 nm with the increase of CdO concentrations.

  18. Fiber Reinforced Concrete (FRC) for High Rise Construction: Case Studies

    Science.gov (United States)

    Gharehbaghi, Koorosh; Chenery, Rhea

    2017-12-01

    Due to its material element, Fiber Reinforced Concrete (FRC) could be stronger than traditional Concrete. This is due to FRC internal material compounds and elements. Furthermore, FRC can also significantly improve flexural strength when compared to traditional Concrete. This improvement in flexural strength can be varied depending on the actual fibers used. Although not new, FRC is gradually gaining popularity in the construction industry, in particular for high rise structures. This is due to its flexural strength, especially for high seismic zones, as it will provide a better solution then reinforced Concrete. The main aim of this paper is to investigate the structural importance of FRC for the high rise construction. Although there has been numerous studies and literature in justifying the FRC for general construction; this paper will consider its use specifically for high rise construction. Moreover, this paper will closely investigate eight case studies from Australian and United States as a part of the FRC validation for high rise construction. In doing so, this paper will examine their Structural Health Monitoring (SHM) to determine their overall structural performance.

  19. Influence of light energy density on heat generation during photoactivation of dental composites with different dentin and composite thickness

    Directory of Open Access Journals (Sweden)

    Ricardo Danil Guiraldo

    2009-08-01

    Full Text Available OBJECTIVE: The aim of this study was to determine the influence of different energy densities on the heat generated during photoactivation of Filtek Z250 (3M/ESPE and Z100 (3M/ESPE composite resins with different dentin and composite thickness. MATERIAL AND METHODS: The temperature increase was registered with a type-K thermocouple connected to a digital thermometer (Iopetherm 46. A chemically polymerized acrylic resin base was prepared to serve as a guide for the thermocouple and as a support for 0.5-, 1.0-, and 1.5-mm-thick bovine dentin discs. Circular elastomer molds (1.0 mm-height x 3.0-mm diameter or 2.0-mm height x 3.0-mm diameter were adapted on the acrylic resin base to standardize the composite resin thickness. A conventional halogen light-curing unit (XL 2500, 3M/ESPE was used with light intensity of 700 mW/cm². Energy density was calculated by the light intensity applied during a certain time with values of 28 J/cm² for Z100 and 14 J/cm² for Filtek Z250. The temperature change data were subjected to three-way ANOVA and Tukey's test at 5% level. RESULTS: The higher energy density (Z100 promoted greater temperature increase (p<0.05 than the lower energy density (Filtek Z250. For both composites and all composite thicknesses, the lowest dentin thickness (0.5 mm yielded significantly higher (p<0.05 temperature increase than the other two dentin thicknesses. The 1-mm-thick composite resin layer yielded significantly higher (p<0.05 temperature changes for both composites and all dentin thicknesses. CONCLUSIONS: Temperature increase was influenced by higher energy density and dentin/composite thickness.

  20. Thick film magnetic nanoparticulate composites and method of manufacture thereof

    Science.gov (United States)

    Ma, Xinqing (Inventor); Zhang, Yide (Inventor); Ge, Shihui (Inventor); Zhang, Zongtao (Inventor); Yan, Dajing (Inventor); Xiao, Danny T. (Inventor)

    2009-01-01

    Thick film magnetic/insulating nanocomposite materials, with significantly reduced core loss, and their manufacture are described. The insulator coated magnetic nanocomposite comprises one or more magnetic components, and an insulating component. The magnetic component comprises nanometer scale particles (about 1 to about 100 nanometers) coated by a thin-layered insulating phase. While the intergrain interaction between the immediate neighboring magnetic nanoparticles separated by the insulating phase provides the desired soft magnetic properties, the insulating material provides high resistivity, which reduces eddy current loss.

  1. Effect of Lamina Thickness of Prepreg on the Surface Accuracy of Carbon Fiber Composite Space Mirrors

    Science.gov (United States)

    Yang, Zhiyong; Tang, Zhanwen; Xie, Yongjie; Shi, Hanqiao; Zhang, Boming; Guo, Hongjun

    2018-02-01

    Composite space mirror can completely replicate the high-precision surface of mould by replication process, but the actual surface accuracy of the replication composite mirror always decreases. Lamina thickness of prepreg affects the layers and layup sequence of composite space mirror, and which would affect surface accuracy of space mirror. In our research, two groups of contrasting cases through finite element analyses (FEA) and comparative experiments were studied; the effect of different lamina thicknesses of prepreg and corresponding lay-up sequences was focused as well. We describe a special analysis model, validated process and result analysis. The simulated and measured surface figures both get the same conclusion. Reducing lamina thickness of prepreg used in replicating composite space mirror is propitious to optimal design of layup sequence for fabricating composite mirror, and could improve its surface accuracy.

  2. Quantifying Local Thickness and Composition in Thin Films of Organic Photovoltaic Blends by Raman Scattering

    KAUST Repository

    Rodríguez-Martínez, Xabier

    2017-07-06

    We report a methodology based on Raman spectroscopy that enables the non-invasive and fast quantitative determination of local thickness and composition in thin films (from few monolayers to hundreds of nm) of one or more components. We apply our methodology to blends of organic conjugated materials relevant in the field of organic photovoltaics. As a first step, we exploit the transfer-matrix formalism to describe the Raman process in thin films including reabsorption and interference effects of the incoming and scattered electric fields. This allows determining the effective solid-state Raman cross-section of each material by studying the dependence of the Raman intensity on film thickness. These effective cross sections are then used to estimate the local thickness and composition in a series of polymer:fullerene blends. We find that the model is accurate within ±10 nm in thickness and ±5 vol% in composition provided that (i) the film thickness is kept below the thickness corresponding to the first maximum of the calculated Raman intensity oscillation; (ii) the materials making up the blend show close enough effective Raman cross-sections; and (iii) the degree of order attained by the conjugated polymer in the blend is similar to that achieved when cast alone. Our methodology opens the possibility to make quantitative maps of composition and thickness over large areas (from microns to centimetres squared) with diffraction-limited resolution and in any multi-component system based thin film technology.

  3. Recent FRC translation experiments on FRX-C/T

    International Nuclear Information System (INIS)

    Rej, D.J.; Armstrong, W.T.; Chrien, R.E.; Hugrass, W.N.; Klingner, P.L.; McKenna, K.F.; Sherwood, E.G.; Siemon, R.E.; Tuszewski, M.

    1985-01-01

    Since the last CT Symposium, several accomplishments have been realized from the FRC translation studies on the FRX-C/T device: (1) FRCs have been launched into, and trapped in, a dc magnetic guide field region without the use of any pulsed ''gate'' coils; (2) detailed studies of translation dynamics have been performed which are consistent with energy conservation, adiabatic compression theory, and 2-D MHD simulations; (3) the confinement properties of translated FRC has been evaluated; (4) translation through either puff or static deuterium gas fill has been demonstrated; (5) higher density (n less than or equal to 4 x 10 15 cm -3 ) FRCs have been translated over 10-m lengths; (6) the n = 2 rotational instability has been stabilized by FRC translation into a weak helical quadrupole field

  4. Influence of increment thickness on dentin bond strength and light transmission of composite base materials.

    Science.gov (United States)

    Omran, Tarek A; Garoushi, Sufyan; Abdulmajeed, Aous A; Lassila, Lippo V; Vallittu, Pekka K

    2017-06-01

    Bulk-fill resin composites (BFCs) are gaining popularity in restorative dentistry due to the reduced chair time and ease of application. This study aimed to evaluate the influence of increment thickness on dentin bond strength and light transmission of different BFCs and a new discontinuous fiber-reinforced composite. One hundred eighty extracted sound human molars were prepared for a shear bond strength (SBS) test. The teeth were divided into four groups (n = 45) according to the resin composite used: regular particulate filler resin composite: (1) G-ænial Anterior [GA] (control); bulk-fill resin composites: (2) Tetric EvoCeram Bulk Fill [TEBF] and (3) SDR; and discontinuous fiber-reinforced composite: (4) everX Posterior [EXP]. Each group was subdivided according to increment thickness (2, 4, and 6 mm). The irradiance power through the material of all groups/subgroups was quantified (MARC® Resin Calibrator; BlueLight Analytics Inc.). Data were analyzed using two-way ANOVA followed by Tukey's post hoc test. SBS and light irradiance decreased as the increment's height increased (p composite used. EXP presented the highest SBS in 2- and 4-mm-thick increments when compared to other composites, although the differences were not statistically significant (p > 0.05). Light irradiance mean values arranged in descending order were (p composites. Discontinuous fiber-reinforced composite showed the highest value of curing light transmission, which was also seen in improved bonding strength to the underlying dentin surface. Discontinuous fiber-reinforced composite can be applied safely in bulks of 4-mm increments same as other bulk-fill composites, although, in 2-mm thickness, the investigated composites showed better performance.

  5. Application of X-ray fluorescence (WDXRF): thickness and chemical composition determination of thin films

    International Nuclear Information System (INIS)

    Scapin, Valdirene de Oliveira.

    2004-01-01

    In this work a procedure is described for thickness and quantitative chemical composition of thin films by wavelength dispersion X-ray fluorescence (WDXRF) using Fundamental Parameters method. This method was validated according to quality assurance standard and applied sample Al, Cr, TiO2, Ni, ZrO2 (single thickness) and Ni/Cr (double thickness) on glass; Ni on steel and metallic zinc and TiO2 on metallic iron (single thickness), all the sample were prepared for physical deposition of vapor (PVD). The thickness had been compared with Absorption (FRX-A) and Rutherford Backscattering Spectrometry (RBS) methods; the result showed good efficiency of the fundamental parameters method. Sample structural characteristics analyzed by X ray diffraction (XRD) showed any influence in the thickness determinations. (author)

  6. Influence of bending test configuration on cracking behavior of FRC

    DEFF Research Database (Denmark)

    Finazzi, Silvia; Paegle, Ieva; Fischer, Gregor

    2014-01-01

    the flexural load-deformation response of FRC. This research focuses particularly on the influence of the appearance and depth of the notch on the cracking behavior of FRC. For this purpose, several specimens, both un-notched and notched with different depths of the notch (25 mm and 45 mm), were tested....... The results obtained in the various tests are compared to determine to what extent the notch can affect cracking behavior and the resulting evaluation of the material according to the method described in the standard. Formation of cracking and the crack development has been documented by means of a digital...

  7. Growth of BaTiO3-PVDF composite thick films by using aerosol deposition

    Science.gov (United States)

    Cho, Sung Hwan; Yoon, Young Joon

    2016-01-01

    Barium titanate (BaTiO3)-polyvinylidene fluoride (PVDF) composite thick films were grown by using aerosol deposition at room temperature with BaTiO3 and PVDF powders. To produce a uniform composition in ceramic and polymer composite films, which show a substantial difference in specific gravity, we used PVDF-coated BaTiO3 powders as the starting materials. An examination of the microstructure confirmed that the BaTiO3 were well distributed in the PVDF matrix in the form of a 0 - 3 compound. The crystallite size in the BaTiO3-PVDF composite thick films was 5 ˜ 50 times higher than that in pure BaTiO3 thick films. PVDF plays a role in suppressing the fragmentation of BaTiO3 powder during the aerosol deposition process and in controlling the relative permittivity.

  8. Design Basis for Fibre Reinforced Concrete (FRC) Pavements

    DEFF Research Database (Denmark)

    Bendixen, Søren; Stang, Henrik

    1996-01-01

    -crack opening relationship can beused to descibe the properties of fibre reinforced concrete (FRC) intension and how the stress-crack opening relationship can beapplied in a simple design scheme for pavements. The projectincludes development of design tools, experiments to determine thestress-crack opening...

  9. Conceptual design of D-3He FRC reactor 'ARTEMIS'

    International Nuclear Information System (INIS)

    Momota, H.; Ishida, A.; Kohzaki, Y.

    1991-07-01

    A comprehensive design study of the D- 3 He fueled field-reversed configuration (FRC) reactor 'ARTEMIS' is carried out for the purpose of proving its attractive characteristics and clarifying the critical issues for a commercial fusion reactor. The FRC burning plasma is stabilized and sustained in a steady equilibrium by means of a preferential trapping of D- 3 He fusion-produced energetic protons. A novel direct energy converter for 15MeV protons is also presented. On the bases of a consistent scenario of the fusion plasma production and simple engineering, a compact and simple reactor concept is presented. The design of the D- 3 He FRC power plant definitely offers the most attractive prospect for energy development. It is environmentally acceptable in view of radio-activity and fuel resources; and the estimated cost of electricity is low compared to a light water reactor. Critical issues concerning physics or engineering for the development of the D- 3 He FRC reactor are clarified. (author)

  10. Simulations of a Plasma Thruster Utilizing the FRC Configuration

    Energy Technology Data Exchange (ETDEWEB)

    Rognlien, T. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Cohen, B. I. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-10

    This report describes work performed by LLNL to model the behavior and performance of a reverse-field configuration (FRC) type of plasma device as a plasma thruster as summarized by Razin et al. [1], which also describes the MNX device at PPPL used to study this concept.

  11. Thickness effect on electric resistivity on polystyrene and carbon black- based composites

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Lopez, S; Vigueras-Santiago, E [Laboratorio de Investigacion y Desarrollo de Materiales Avanzados (LIDMA) Facultad de Quimica, Paseo Colon Esquina con Paseo Tollocan, s/n, CP 50000, Toluca (Mexico); Mayorga-Rojas, M; Reyes-Contreras, D, E-mail: eviguerass@uaemex.m [Facultad de Ciencias, Universidad Autonoma del Estado de Mexico. Av. Instituto Literario 100 Ote. C. P. 50000, Toluca (Mexico)

    2009-05-01

    Changes on electrical resistivity were experimentally studied for polystyrene and carbon black-based composites respect to the temperature. 22% w/w carbon black composite films at 30{mu}m, 2mm y 1cm thick were submitted to thermal heating-cooling cycles from room temperature to 100 deg. C, slightly up to T{sub g} of the composite. For each cycle changes on electrical resistivity constituent a hysteresis loop that depends on the sample thickness. The changes during the heating stage could be explained as a consequence of the thermal expansion and mobility of the polymer chains at T{sub g}, producing a disconnecting of the electrical contacts among carbon black particles and an important increasing (200%) of the electrical resistivity. For each cycle, the hysteresis loop was observed in thicker samples, whereas for 30 mu m thickness sample the hysteresis loop was lost after four cycles.

  12. Lead Equivalent Thickness Measurement for Mixed Compositions of Barium Plaster Block

    International Nuclear Information System (INIS)

    Norriza Mohd Isa; Muhammad Jamal Muhammad Isa; Nur Shahriza Zainuddin; Mohd Khairusalih Md Zin; Shahrul Azlan Azizan

    2016-01-01

    Measurement of lead equivalent thickness for ionizing radiation exposure room wall shall be performed as stated in Malaysian Standard MS 838. A few numbers of sample blocks with different mixture of barium plaster compositions based and varies certain thickness as a shielding material for exposure room wall belong to a local company were tested by using Cs-137, Co-60 and Am-241 with different activities . Radiations passed through the samples were detected with calibrated survey meter. The distance between radiation source and the detector is about 40 cm. Lead uniformity test on the samples was also determined at three labeled points on the samples. Lead equivalent thicknesses for the samples were evaluated based on a calibration graph that was plotted with lead sheets and with the radiation sources. Results shown that lead equivalent thickness for the samples with same actual physical thickness represent different values for different sources. (author)

  13. Influence of curing time, overlay material and thickness on three light-curing composites used for luting indirect composite restorations.

    Science.gov (United States)

    D'Arcangelo, Camillo; De Angelis, Francesco; Vadini, Mirco; Carluccio, Fabio; Vitalone, Laura Merla; D'Amario, Maurizio

    2012-08-01

    To assess the microhardness of three resin composites employed in the adhesive luting of indirect composite restorations and examine the influence of the overlay material and thickness as well as the curing time on polymerization rate. Three commercially available resin composites were selected: Enamel Plus HRI (Micerium) (ENA), Saremco ELS (Saremco Dental) (SAR), Esthet-X HD (Dentsply/DeTrey) (EST-X). Post-polymerized cylinders of 6 different thicknesses were produced and used as overlays: 2 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, and 6 mm. Two-mm-thick disks were produced and employed as underlays. A standardized amount of composite paste was placed between the underlay and the overlay surfaces which were maintained at a fixed distance of 0.5 mm. Light curing of the luting composite layer was performed through the overlays for 40, 80, or 120 s. For each specimen, the composite to be cured, the cured overlay, and the underlay were made out of the same batch of resin composite. All specimens were assigned to three experimental groups on the basis of the resin composite used, and to subgroups on the basis of the overlay thickness and the curing time, resulting in 54 experimental subgroups (n = 5). Forty-five additional specimens, 15 for each material under investigation, were produced and subjected to 40, 80, or 120 s of light curing using a microscope glass as an overlay; they were assigned to 9 control subgroups (n = 5). Three Vicker's hardness (VH) indentations were performed on each specimen. Means and standard deviations were calculated. Data were statistically analyzed using 3-way ANOVA. Within the same material, VH values lower than 55% of control were not considered acceptable. The used material, the overlay thickness, and the curing time significantly influenced VH values. In the ENA group, acceptable hardness values were achieved with 3.5-mm or thinner overlays after 120 or 80 s curing time (VH 41.75 and 39.32, respectively), and with 2-mm overlays after 40 s (VH 54

  14. [FRC measurement in intensive care patients. A definition of standards].

    Science.gov (United States)

    Wauer, H J; Lorenz, B A; Kox, W J

    1998-10-01

    Determination of Functional Residual Capacity (FRC) can be performed through washout methods, indicator gas dilution or bodyplethysmography. Some of these techniques have been adapted for use in intensive care patients whilst being mechanically ventilated. However, most measurement setups are bulky, cumbersome to use and their running costs are high. Hence FRC measurement has not become a routine method in intensive care although it offers considerable advantages in the management of ventilated patients such as the determination of "best PEEP", the detection of progressive alveolar collapse in the course of acute lung injury and during weaning from mechanical ventilation. Up to now most efforts to improve and simplify FRC measurement were made at the expense of accuracy. An ideal method ought to be accurate, easy to handle and cost-effective. It should supply not only FRC data but also information about intrapulmonary gas distribution and dead space. These demands can be met using modern data acquisition software. The pros and cons of all methods available for FRC measurement are discussed in view of their suitability for intensive care patients. A conventional nitrogen washout using emission spectroscopy for measurement of nitrogen concentration gives satisfying exact values for the determination of the parameters mentioned above. The measurement error can be lowered under 5% by special corrections for flow and nitrogen signal (delay and rise times, changes of gas viscosity). For flow measurement a normal pneumotachograph can be used. Using a laptop computer for data acquisition the bed-side monitor fulfills most of the demands in intensive care. It is then also possible to measure indices of intrapulmonary gas distribution such as Alveolar Mixing Efficiency and Lung Clearance Index.

  15. Quantitative characterization of the composition, thickness and orientation of thin films in the analytical electron microscope

    International Nuclear Information System (INIS)

    Williams, D.B.; Watanabe, M.; Papworth, A.J.; Li, J.C.

    2003-01-01

    Compositional variations in thin films can introduce lattice-parameter changes and thus create stresses, in addition to the more usual stresses introduced by substrate-film mismatch, differential thermal expansion, etc. Analytical electron microscopy comprising X-ray energy-dispersive spectrometry within a probe-forming field-emission gun scanning transmission electron microscope (STEM) is one of the most powerful methods of composition measurement on the nanometer scale, essential for thin-film analysis. Recently, with the development of improved X-ray collection efficiencies and quantitative computation methods it has proved possible to map out composition variations in thin films with a spatial resolution approaching 1-2 nm. Because the absorption of X-rays is dependent on the film thickness, concurrent composition and film thickness determination is another advantage of X-ray microanalysis, thus correlating thickness and composition variations, either of which may contribute to stresses in the film. Specific phenomena such as segregation to interfaces and boundaries in the film are ideally suited to analysis by X-ray mapping. This approach also permits multiple boundaries to be examined, giving some statistical certainty to the analysis particularly in nano-crystalline materials with grain sizes greater than the film thickness. Boundary segregation is strongly affected by crystallographic misorientation and it is now possible to map out the orientation between many different grains in the (S)TEM

  16. Effect of surface treatment of FRC-Post on bonding strength to resin cements

    Directory of Open Access Journals (Sweden)

    Chan-Hyun Park,

    2011-03-01

    Full Text Available Objectives The purpose of this study was to evaluate the effect of surface treatment of FRC-Post on bonding strength to resin cements. Materials and Methods Pre-surface treated LuxaPost (DMG, Rely-X Fiber Post (3M ESPE and self adhesive resin cement Rely-X Unicem (3M ESPE, conventional resin cement Rely-X ARC (3M ESPE, and Rely-X Ceramic Primer (3M ESPE were used. After completing the surface treatments of the posts, posts and resin cement were placed in clear molds and photo-activation was performed. The specimens were sectioned perpendicular to the FRC-Post into 2 mm-thick segments, and push-out strength were measured. The results of bond strength value were statistically analyzed using independent samples t-test and one-way ANOVA with multiple comparisons using Scheffe's test. Results Silanization of posts affect to the bond strength in LuxaPost, and did not affect in Rely-X Fiber Post. Rely-X ARC showed higher value than Rely-X Unicem. Conclusions Silanization is needed to enhance the bond strength between LuxaPost and resin cements.

  17. Modeling and characterization of through-the-thickness properties of 3D woven composites

    Science.gov (United States)

    Hartranft, Dru; Pravizi-Majidi, Azar; Chou, Tsu-Wei

    1995-01-01

    The through-the-thickness properties of three-dimensionally (3D) woven carbon/epoxy composites have been studied. The investigation aimed at the evaluation and development of test methodologies for the property characterization in the thickness direction, and the establishment of fiber architectures were studied: layer-to-layer Angle Interlock, through-the-thickness Orthogonal woven preform with surface pile was also designed and manufactured for the fabrication of tensile test coupons with integrated grips. All the preforms were infiltrated by the resin transfer molding technique. The microstructures of the composites were characterized along the warp and fill (weft) directions to determine the degree of yarn undulations, yarn cross-sectional shapes, and microstructural dimensions. These parameters were correlated to the fiber architecture. Specimens were designed and tested for the direct measurement of the through-the-thickness tensile, compressive and shear properties of the composites. Design optimization was conducted through the analysis of the stress fields within the specimen coupled with experimental verification. The experimentally-derived elastic properties in the thickness direction compared well with analytical predictions obtained from a volume averaging model.

  18. Thickness and composition of ultrathin SiO2 layers on Si

    NARCIS (Netherlands)

    van der Marel, C; Verheijen, M.A.; Tamminga, Y; Pijnenburg, RHW; Tombros, N; Cubaynes, F

    2004-01-01

    Ultrathin SiO2 layers are of importance for the semiconductor industry. One of the techniques that can be used to determine the chemical composition and thickness of this type of layers is x-ray photoelectron spectroscopy (XPS). As shown by Seah and Spencer [Surf. Interface Anal. 33, 640 (2002)], it

  19. A thick level set interface model for simulating fatigue-drive delamination in composites

    NARCIS (Netherlands)

    Latifi, M.; Van der Meer, F.P.; Sluys, L.J.

    2015-01-01

    This paper presents a new damage model for simulating fatigue-driven delamination in composite laminates. This model is developed based on the Thick Level Set approach (TLS) and provides a favorable link between damage mechanics and fracture mechanics through the non-local evaluation of the energy

  20. Quantifying Local Thickness and Composition in Thin Films of Organic Photovoltaic Blends by Raman Scattering

    KAUST Repository

    Rodrí guez-Martí nez, Xabier; Vezie, Michelle S; Shi, Xingyuan; McCulloch, Iain; Nelson, Jenny; Goni, Alejandro R; Campoy-Quiles, Mariano

    2017-01-01

    We report a methodology based on Raman spectroscopy that enables the non-invasive and fast quantitative determination of local thickness and composition in thin films (from few monolayers to hundreds of nm) of one or more components. We apply our

  1. Translation of an FRC plasma into a quasi-spherical confinement region

    International Nuclear Information System (INIS)

    Sekiguchi, Jun'ichi; Asai, Tomohiko; Takahashi, Tsutomu; Takahashi, Toshiki

    2014-01-01

    Translation of a Field-Reversed Configuration (FRC) into a quasi-spherical confinement region with super-alfvenic translation speed has been successfully conducted. Translation speed can be controlled in the range from 80 to 150 km/s by changing statically filled gas pressure. The translated FRC experiences radial decompression process rapidly when it enters into the confinement chamber. The separatrix shape of translated FRC is controlled through the translation process. Especially, in the case of FRC translation into deuterium gas atmosphere, elongation of the FRC is roughly unity. It indicates possible application of center solenoid onto the high-beta compact torus of FRC. Also, as a new finding, a rotational instability with an n=2 deformation has been observed in the translated FRC. (author)

  2. A convenient method for X-ray analysis in TEM that measures mass thickness and composition

    Science.gov (United States)

    Statham, P.; Sagar, J.; Holland, J.; Pinard, P.; Lozano-Perez, S.

    2018-01-01

    We consider a new approach for quantitative analysis in transmission electron microscopy (TEM) that offers the same convenience as single-standard quantitative analysis in scanning electron microscopy (SEM). Instead of a bulk standard, a thin film with known mass thickness is used as a reference. The procedure involves recording an X-ray spectrum from the reference film for each session of acquisitions on real specimens. There is no need to measure the beam current; the current only needs to be stable for the duration of the session. A new reference standard with a large (1 mm x 1 mm) area of uniform thickness of 100 nm silicon nitride is used to reveal regions of X-ray detector occlusion that would give misleading results for any X-ray method that measures thickness. Unlike previous methods, the new X-ray method does not require an accurate beam current monitor but delivers equivalent accuracy in mass thickness measurement. Quantitative compositional results are also automatically corrected for specimen self-absorption. The new method is tested using a wedge specimen of Inconel 600 that is used to calibrate the high angle angular dark field (HAADF) signal to provide a thickness reference and results are compared with electron energy-loss spectrometry (EELS) measurements. For the new X-ray method, element composition results are consistent with the expected composition for the alloy and the mass thickness measurement is shown to provide an accurate alternative to EELS for thickness determination in TEM without the uncertainty associated with mean free path estimates.

  3. Translucency and masking ability of various composite resins at different thicknesses.

    Science.gov (United States)

    Darabi, Farideh; Radafshar, Golpar; Tavangar, Maryam; Davaloo, Reza; Khosravian, Aref; Mirfarhadi, Nastaran

    2014-09-01

    Optical properties of the composite resins, concerning their translucency and thickness, are affected by discolored tooth structure or inherent darkness of the oral cavity. This study aimed to compare the translucency parameter (TP) of five different composite resins in different thicknesses and to evaluate their masking ability in black backgrounds. Five brands of composite resins; Gradia (GC) and Crystalline (Confi-dental) in opaque A2 (OA2), Vit-l-escence (Ultradent) in opaque snow (OS), Herculite XRV (Kerr) and Opallis (FGM) in dentin A2 (DA2) shades were selected to enroll the study. Color coordinates of each composite were determined at 0.5, 1, and 1.5 mm thicknesses on a white backing, the backing of material itself and a black backing were calculated by using a spectrophotometer to evaluate the translucency parameter (TP) of the study materials. The masking ability was also calculated from the specimens on the material itself and on black backing. The values under 2 were estimated as imperceptible. One-way ANOVA, T-test and Tukey HSD were employed for statistical analysis. The masking ability values, recorded for the 1.5 mm-thick specimens, were in the range of imperceptible except for the Herculite. There was no difference in TP values of the materials at 1.5 mm thickness. Opaque snow shade of Vit-l-escence and opaque A2 shade of Gradia showed lower TP values in comparison with the other 1 and 0.5 mm-thick materials and this difference was statistically significant (pcomposite resins could not mask the black background color.

  4. Material properties of frc with recycled aggregate

    Czech Academy of Sciences Publication Activity Database

    Trčková, Jiřina; Procházka, P.

    2011-01-01

    Roč. 8, č. 2 (2011), s. 105-113 ISSN 1214-9705 R&D Projects: GA ČR GA103/08/1197 Institutional research plan: CEZ:AV0Z30460519 Keywords : recycled aggregate * concrete composite * pullout test Subject RIV: JM - Building Engineering Impact factor: 0.530, year: 2011 http://www.irsm.cas.cz/abstracts/AGG/02_11/1_Trckova.pdf

  5. Influence of the polymeric coating thickness on the electrochemical performance of Carbon Fiber/PAni composites

    Directory of Open Access Journals (Sweden)

    Carla Polo Fonseca

    2015-10-01

    Full Text Available Abstract Carbon fiber/polyaniline composites (CF/PAni were synthesized at three different deposition time of 30, 60 and 90 min by oxidative polymerization. The composite materials were morphologically and physically characterized by scanning electron microscopy and by Raman spectroscopy, respectively. Their electrochemical responses were analyzed by cyclic voltammetry, by galvanostatic test, and by electrochemical impedance spectroscopy. The influence of the PAni layer thickness deposited on carbon fibers for the composite formation as well as for their electrochemical properties was discussed. The CF/PAni-30 showed a nanometric thickness with more homogeneous morphology compared to those formed in deposition times of 60 and 90 min. It also showed, from the electrochemical impedance spectroscopy measurements, the lowest charge transfer resistance value associated to the its highest value for the double-layer capacitance of 180 Fg-1 making it a very strong candidate as a supercapacitor electrode.

  6. Quantitative CT: Associations between Emphysema, Airway Wall Thickness and Body Composition in COPD

    DEFF Research Database (Denmark)

    Rutten, Erica P A; Grydeland, Thomas B; Pillai, Sreekumar G

    2011-01-01

    The objective of the present study was to determine the association between CT phenotypes-emphysema by low attenuation area and bronchitis by airway wall thickness-and body composition parameters in a large cohort of subjects with and without COPD. In 452 COPD subjects and 459 subjects without COPD......, CT scans were performed to determine emphysema (%LAA), airway wall thickness (AWT-Pi10), and lung mass. Muscle wasting based on FFMI was assessed by bioelectrical impedance. In both the men and women with COPD, FFMI was negatively associated with %LAA. FMI was positively associated with AWT-Pi10...... in both subjects with and without COPD. Among the subjects with muscle wasting, the percentage emphysema was high, but the predictive value was moderate. In conclusion, the present study strengthens the hypothesis that the subgroup of COPD cases with muscle wasting have emphysema. Airway wall thickness...

  7. Quantitative CT: Associations between Emphysema, Airway Wall Thickness and Body Composition in COPD

    DEFF Research Database (Denmark)

    Rutten, Erica P A; Grydeland, Thomas B; Pillai, Sreekumar G

    2011-01-01

    , CT scans were performed to determine emphysema (%LAA), airway wall thickness (AWT-Pi10), and lung mass. Muscle wasting based on FFMI was assessed by bioelectrical impedance. In both the men and women with COPD, FFMI was negatively associated with %LAA. FMI was positively associated with AWT-Pi10......The objective of the present study was to determine the association between CT phenotypes-emphysema by low attenuation area and bronchitis by airway wall thickness-and body composition parameters in a large cohort of subjects with and without COPD. In 452 COPD subjects and 459 subjects without COPD...... in both subjects with and without COPD. Among the subjects with muscle wasting, the percentage emphysema was high, but the predictive value was moderate. In conclusion, the present study strengthens the hypothesis that the subgroup of COPD cases with muscle wasting have emphysema. Airway wall thickness...

  8. Microhardness of resin composite materials light-cured through fiber reinforced composite.

    NARCIS (Netherlands)

    Fennis, W.M.M.; Ray, N.J.; Creugers, N.H.J.; Kreulen, C.M.

    2009-01-01

    OBJECTIVES: To compare polymerization efficiency of resin composite basing materials when light-cured through resin composite and fiber reinforced composite (FRC) by testing microhardness. METHODS: Simulated indirect restorations were prepared by application of resin composite (Clearfil AP-X) or FRC

  9. Theoretical and experimental investigations of thickness- stretch modes in 1-3 piezoelectric composites

    International Nuclear Information System (INIS)

    Yang, Z T; Zeng, D P; He, M; Wang, H

    2015-01-01

    Bulk piezoelectric ceramics operating in thickness-stretch (TSt) modes have been widely used in acoustic-related devices. However, the fundamental TSt waves are always coupled with other modes, and the occurrence of these spurious modes in bulk piezoelectric ceramics affects its performance. To suppress the spurious modes, 1-3 piezoelectric composites are promising candidates. However, theoretical modeling of multiphase ceramic composite objects is very complex. In this study, a 1-3 piezoelectric composite sample and a bulk piezoelectric sample are fabricated. The electrical impedance of these two samples are compared. A simple analytical TSt vibration mode from the three dimensional equations of linear piezoelectricity is used to model the performance of 1-3 piezoelectric composites. The theoretical results agree well with the experimental results. (paper)

  10. Discrete Material and Thickness Optimization of laminated composite structures including failure criteria

    DEFF Research Database (Denmark)

    Lund, Erik

    2017-01-01

    This work extends the Discrete Material and Thickness Optimization approach to structural optimization problems where strength considerations in the form of failure criteria are taken into account for laminated composite structures. It takes offset in the density approaches applied for stress...... constrained topology optimization of single-material problems and develops formulations for multi-material topology optimization problems applied for laminated composite structures. The method can be applied for both stress- and strain-based failure criteria. The large number of local constraints is reduced...

  11. Merging formation of FRC and its application to high-beta ST formation

    International Nuclear Information System (INIS)

    Ono, Y.; Inomoto, M.; Ueda, Y.; Matsuyama, T.; Ohshima, Y.; Katsurai, M.

    2001-01-01

    Merging formation of field-reversed configuration (FRC) explored not only a new scenario of highly-efficient FRC formation/amplification experiment but also a new boundary research between FRC, spheromak and spherical tokamak (ST). A new finding is that the produced FRC is transformed stably into an ultra-high-β ST by applying external toroidal field B t,ext . The toroidal field was observed to vanish around magnetic axis after the B t,ext application to the FRC, indicating formation of diamagnetic ST. The hollow current profile of FRC was maintained during the equilibrium transition, eliminating a need for the difficult hollow-current-formation process of start-up discharge of high-β ST. The energy-conversion effect of merging transformed the force-free merging spheromaks with paramagnetic current into the FRC with diamagnetic current and the further application of B t,ext did the FRC into the ultra-high-β (>60%)/diamagnetic ST, indicating the close relationship between FRC and ST in second stability. (author)

  12. Design considerations for a large anti s FRC facility

    International Nuclear Information System (INIS)

    Hoffman, A.L.; Crawford, E.A.; Milroy, R.D.; Slough, J.T.; Steinhauer, L.C.

    1986-01-01

    The number of internal gyroradii between the field null and the separatrix of field-reversed-configurations (FRC), has been identified as a key parameter governing both stability and transport. Present experiments have anti s in the range of 2, while values of about 30 are thought to be necessary in a reactor. It is thus desirable to conduct experiments in some intermediate range. A value of 10 has been chosen as a reasonable goal for a next experiment. In this paper some of the design considerations and cost optimization procedures used to pick a point design for an anti s = 10 facility are discussed

  13. Experimental investigation of effect of specimen thickness on fracture toughness of Al-TiC composites

    Directory of Open Access Journals (Sweden)

    M. S. Raviraj

    2016-07-01

    Full Text Available In this paper, the macro and micro-mechanical fracture behavior was studied for aluminum (Al6061 alloy matrix, reinforced with various proportions of TiC particles such as 3wt%, 5wt% and 7wt%. The Al6061-TiC metal matrix composites were produced by stir casting method to ensure uniform distribution of the TiC particulates in the Al matrix. The compact tension (CT specimens were machined according to ASTM E399 specifications to evaluate the fracture toughness for Al6061-TiC metal matrix composites. The CT specimens were machined for crack to width (a/W ratio of 0.5 and thickness to width (B/W ratios of 0.2 to 0.7 with an increment of 0.1. Load versus crack mouth opening displacement (CMOD data was plotted to estimate stress intensity factor KQ for various thicknesses of the specimen. The fracture toughness KIC was obtained by plotting stress intensity factor versus thickness to width ratios of specimen data. The fracture toughness of these composites varied between 16.4-19.2 MPa√m. Scanning Electron Microscope (SEM studies was made on the fractured surface of the specimens to understand the micro-mechanisms of failure involved in these composites. Void initiation is more significant in the matrix near the interface. The micro-cracks grow from these micro-voids and crack propagates by linking these micro cracks locating the crack path preferentially in the matrix adjacent to the interface indicating ductile fracture.

  14. Theoretical models to predict the mechanical behavior of thick composite tubes

    Directory of Open Access Journals (Sweden)

    Volnei Tita

    2012-02-01

    Full Text Available This paper shows theoretical models (analytical formulations to predict the mechanical behavior of thick composite tubes and how some parameters can influence this behavior. Thus, firstly, it was developed the analytical formulations for a pressurized tube made of composite material with a single thick ply and only one lamination angle. For this case, the stress distribution and the displacement fields are investigated as function of different lamination angles and reinforcement volume fractions. The results obtained by the theoretical model are physic consistent and coherent with the literature information. After that, the previous formulations are extended in order to predict the mechanical behavior of a thick laminated tube. Both analytical formulations are implemented as a computational tool via Matlab code. The results obtained by the computational tool are compared to the finite element analyses, and the stress distribution is considered coherent. Moreover, the engineering computational tool is used to perform failure analysis, using different types of failure criteria, which identifies the damaged ply and the mode of failure.

  15. Vibrations of laminated composite thick shells of revolution having meridionally varying curvature

    International Nuclear Information System (INIS)

    Suzuki, Katsuyoshi; Shikanai, Genji; Baba, Iwato

    1998-01-01

    An exact solution is presented for solving free vibrations of laminated composite thick shells of revolution having meridionally varying curvature. Based on the thick lamination theory considering the shear deformation and rotary inertia, equations of motion and boundary conditions are obtained from the stationary conditions of the Lagrangian. The equations of motion are solved exactly by using a power series expansion for symmetrically laminated cross-ply shells. Frequencies and mode shapes of shells of revolution having elliptical and parabolical meridians are presented for both ends clamped, and the effects of shear deformation and rotary inertia are discussed by comparing the results from the present theory with those from the thin lamination theory. (author)

  16. DMTO – a method for Discrete Material and Thickness Optimization of laminated composite structures

    DEFF Research Database (Denmark)

    Sørensen, Søren Nørgaard; Sørensen, Rene; Lund, Erik

    2014-01-01

    This paper presents a gradient based topology optimization method for Discrete Material and Thickness Optimization of laminated composite structures, labelled the DMTOmethod. The capabilities of the proposed method are demonstrated on mass minimization, subject to constraints on the structural...... criteria; buckling load factors, eigenfrequencies, and limited displacements. Furthermore, common design guidelines or rules, referred to as manufacturing constraints, are included explicitly in the optimization problem as series of linear inequalities. The material selection and thickness variation...... to manufacturability. The results will thus give insight into the relation between potential weight saving and design complexity. The results show that the DMTO method is capable of solving the problems robustly with only few intermediate valued design variables....

  17. The influence of lay-up and thickness on composite impact damage and compression strength

    Science.gov (United States)

    Guynn, E. G.; Obrien, T. K.

    1985-01-01

    The effects of composite stacking sequence, thickness, and percentage of zero-degree plies on the size, shape, and distribution of delamination through the laminate thickness and on residual compression strength following impact were studied. Graphite/epoxy laminates were impacted with an 0.5 inch diameter aluminum sphere at a specific low or high velocity. Impact damage was measured nondestructively by ultrasonic C-scans and X-radiography and destructively by the deply technique, and compression strength tests were performed. It was found that differences in compression failure strain due to stacking sequence were small, while laminates with very low percentages of zero-degree plies had similar failure loads but higher failure strains than laminates with higher percentages of zero-degree plies. Failure strain did not correlate with planar impact damage area, and delaminations in impact regions were associated with matrix cracking.

  18. Steady state theta pinch concept for slow formation of FRC

    International Nuclear Information System (INIS)

    Hirano, K.

    1987-05-01

    A steady state high beta plasma flow through a channel along the magnetic field increasing downstream can be regarded as a ''steady state theta pinch'', because if we see the plasma riding on the flow we should observe very similar process taking place in a theta pinch. Anticipating to produce an FRC without using very high voltage technics such as the ones required in a conventional theta pinch, we have studied after the analogy a ''steady state reversed field theta pinch'' which is brought about by steady head-on collision of counter plasma streams along the channel as ejected from two identical co-axial plasma sources mounted at the both ends of the apparatus. The ideal Poisson and shock adiabatic flow models are employed for the analysis of the steady colliding process. It is demonstrated that an FRC involving large numbers of particles is produced only by the weak shock mode which is achieved in case energetic plasma flow is decelerated almost to be stagnated through Poisson adiabatic process before the streams are collided. (author)

  19. Bandgap Engineering of InP QDs Through Shell Thickness and Composition

    Energy Technology Data Exchange (ETDEWEB)

    Dennis, Allison M. [Los Alamos National Laboratory; Mangum, Benjamin D. [Los Alamos National Laboratory; Piryatinski, Andrei [Los Alamos National Laboratory; Park, Young-Shin [Los Alamos National Laboratory; Htoon, Han [Los Alamos National Laboratory; Hollingsworth, Jennifer A. [Los Alamos National Laboratory

    2012-06-21

    Fields as diverse as biological imaging and telecommunications utilize the unique photophysical and electronic properties of nanocrystal quantum dots (NQDs). The development of new NQD compositions promises material properties optimized for specific applications, while addressing material toxicity. Indium phosphide (InP) offers a 'green' alternative to the traditional cadmium-based NQDs, but suffers from extreme susceptibility to oxidation. Coating InP cores with more stable shell materials significantly improves nanocrystal resistance to oxidation and photostability. We have investigated several new InP-based core-shell compositions, correlating our results with theoretical predictions of their optical and electronic properties. Specifically, we can tailor the InP core-shell QDs to a type-I, quasi-type-II, or type-II bandgap structure with emission wavelengths ranging from 500-1300 nm depending on the shell material used (ZnS, ZnSe, CdS, or CdSe) and the thickness of the shell. Single molecule microscopy assessments of photobleaching and blinking are used to correlate NQD properties with shell thickness.

  20. Dielectric and Piezoelectric Properties of PZT Composite Thick Films with Variable Solution to Powder Ratios.

    Science.gov (United States)

    Wu, Dawei; Zhou, Qifa; Shung, Koping Kirk; Bharadwaja, Srowthi N; Zhang, Dongshe; Zheng, Haixing

    2009-05-08

    The use of PZT films in sliver-mode high-frequency ultrasonic transducers applications requires thick, dense, and crack-free films with excellent piezoelectric and dielectric properties. In this work, PZT composite solutions were used to deposit PZT films >10 μm in thickness. It was found that the functional properties depend strongly on the mass ratio of PZT sol-gel solution to PZT powder in the composite solution. Both the remanent polarization, P(r), and transverse piezoelectric coefficient, e(31,) (f), increase with increasing proportion of the sol-gel solution in the precursor. Films prepared using a solution-to-powder mass ratio of 0.5 have a remanent polarization of 8 μC/cm(2), a dielectric constant of 450 (at 1 kHz), and e(31,) (f) = -2.8 C/m(2). Increasing the solution-to-powder mass ratio to 6, the films were found to have remanent polarizations as large as 37 μC/cm(2), a dielectric constant of 1250 (at 1 kHz) and e(31,) (f) = -5.8 C/m(2).

  1. Creep Modeling in a Composite Rotating Disc with Thickness Variation in Presence of Residual Stress

    Directory of Open Access Journals (Sweden)

    Vandana Gupta

    2012-01-01

    Full Text Available Steady-state creep response in a rotating disc made of Al-SiC (particle composite having linearly varying thickness has been carried out using isotropic/anisotropic Hoffman yield criterion and results are compared with those using von Mises yield criterion/Hill's criterion ignoring difference in yield stresses. The steady-state creep behavior has been described by Sherby's creep law. The material parameters characterizing difference in yield stresses have been used from the available experimental results in literature. Stress and strain rate distributions developed due to rotation have been calculated. It is concluded that the stress and strain distributions got affected from the thermal residual stress in an isotropic/anisotropic rotating disc, although the effect of residual stress on creep behavior in an anisotropic rotating disc is observed to be lower than those observed in an isotropic disc. Thus, the presence of residual stress in composite rotating disc with varying thickness needs attention for designing a disc.

  2. Thickness and composition of ultrathin SiO2 layers on Si

    International Nuclear Information System (INIS)

    Marel, C. van der; Verheijen, M.A.; Tamminga, Y.; Pijnenburg, R.H.W.; Tombros, N.; Cubaynes, F.

    2004-01-01

    Ultrathin SiO 2 layers are of importance for the semiconductor industry. One of the techniques that can be used to determine the chemical composition and thickness of this type of layers is x-ray photoelectron spectroscopy (XPS). As shown by Seah and Spencer [Surf. Interface Anal. 33, 640 (2002)], it is not trivial to characterize this type of layer by means of XPS in a reliable way. We have investigated a series of ultrathin layers of SiO 2 on Si (in the range from 0.3 to 3 nm) using XPS. The samples were also analyzed by means of transmission electron microscopy (TEM), Rutherford backscattering (RBS), and ellipsometry. The thickness of the SiO 2 layers (d) was determined from the XPS results using three different approaches: the 'standard' equation (Seah and Spencer) for d, an overlayer-substrate model calculation, and the QUASES-Tougaard [Surf. Interface Anal. 26, 249 (1998), QUASES-Tougaard: Software package for Quantitative Analysis of Surfaces by Electron Spectroscopy, version 4.4 (2000); http://www.quases.com] method. Good agreement was obtained between the results of XPS analyses using the 'standard' equation, the overlayer-substrate model calculation, and RBS results. The QUASES-Tougaard results were approximately 62% above the other XPS results. The optical values for the thickness were always slightly higher than the thickness according to XPS or RBS. Using the model calculation, these (relatively small) deviations from the optical results could be explained as being a consequence of surface contaminations with hydrocarbons. For a thickness above 2.5 nm, the TEM results were in good agreement with the results obtained from the other techniques (apart from QUASES-Tougaard). Below 2.5 nm, significant deviations were found between RBS, XPS, and optical data on the one hand and TEM results on the other hand; the deviations became larger as the thickness of the SiO 2 decreased. This effect may be related to interface states of oxygen, which have been

  3. Thickness, Composition and Physical Properties of Crust in Iceland's Neovolcanic Zone

    Science.gov (United States)

    Kelley, D. F.; Barton, M.

    2005-12-01

    We report the results of an ongoing effort to use petrologic data to estimate the thickness, composition and physical properties of crust in the neovolcanic zone of Iceland. The objectives are to constrain the depths of magma chambers, calculate geothermal gradients, and resolve discrepancies in the interpretation of geophysical data (primarily gravity and seismic). 1788 whole rock analyses and 170 glass analyses of erupted Icelandic lavas from the neovolcanic zone have been compiled from published papers. Variation diagrams indicate that Icelandic magmas evolved primarily by crystallization of Ol-Cpx-Plag, whereas the most primitive magmas evolved by crystallization of Ol alone. Phase equilibrium constraints were used to quantitatively estimate the pressure of crystallization along the Ol-Cpx-Plag cotectic and hence the depths of the magma chambers. The latter occur at 20±6.2 km, and the average temperature of magma in the chambers is 1207±26°C (also estimated from phase equilibrium constraints). The results suggest magma chambers located at the base of the crust indicating that the latter is ~20 km thick along the neovolcanic zone in agreement with estimates based on geophysical studies. It is argued that the average composition of erupted lavas provides an accurate estimate of crustal composition because magma evolution occurs in sub-crustal chambers. A representative geothermal gradient was calculated using the average crust composition and surface heat flow measurements. The calculated gradient is consistent with the periodic presence of shallow intracrustal magma chambers at ~5 km depth that have been detected seismically, with hydrothermal circulation in the uppermost 3 km of the crust, and with temperatures of ~1200°C at the base of the crust. The geotherm was used to calculate a density-depth profile for average crust. Densities decrease with depth if a low-pressure mineralogy is used for the crust. This density inversion can be avoided by assuming

  4. Solidifier effectiveness : variation due to oil composition, oil thickness and temperature

    International Nuclear Information System (INIS)

    Fieldhouse, B.; Fingas, M.

    2009-01-01

    This paper provided an overview of solidifier types and composition. Solidifiers are a class of spill treating agents that offer an effective means to convert a liquid oil into a solid material. They are used as a treatment option for oil spills on water. This paper also reported on recent laboratory studies that consist of 4 components: (1) a qualitative examination of the characteristics of the interaction of a broad range of solidifier products with a standard oil to evaluate reaction rate, states of solidification, and the impact of dosage, (2) a comparison of a smaller subset of solidifiers on the standard oil at lower temperatures, (3) solidifier treatment on a range of oils of varying physical properties and composition to assess the potential scope of application, and (4) the treatment of a series of small-scale oil layers of varying thickness to determine the significance of oil thickness on solidifier effectiveness and recovery. This paper also reviewed solidifier chemistry with particular reference to polymer sorbents; cross-linking agents; and cross-linking agents and polymeric sorbents combined. Toxicity is also an important issue regarding solidifiers. The aquatic toxicity of solidifiers is low and not measurable as the products are not water-soluble. There have not been any studies on the effects of the solidifier or the treated oil on surface feeders and shoreline wildlife that may come into contact with the products. It was concluded that oil composition may play a major role in solidifier effectiveness. The effectiveness of solidifiers is also inhibited at reduced temperatures, increased viscosity and density of the oil. 25 refs., 5 tabs., 2 figs., 1 appendix

  5. D-3He fueled FRC reactor 'ARTEMIS-L'

    International Nuclear Information System (INIS)

    Momota, Hiromu; Tomita, Yukihiro; Ishida, Akio; Kohzaki, Yasuji; Nakao, Yasuyuki; Nishikawa, Masabumi; Ohi, Shoichi; Ohnishi, Masami.

    1992-09-01

    A neutron-lean D- 3 He fueled field reversed configuration (FRC) fusion reactor is studied on the bases of former high-efficiency ARTEMIS design. Certain improvements such as effective axial contracting plasma heating and cusp-type direct energy converters as well as an empirical scale of the energy confinement are introduced. The resultant total neutron load onto the first wall of the plasma chamber is as low as 0.1 MW/m 2 , which enable the life of the first wall or the structural materials to be longer than the whole life of the reactor. The attractive characteristics of the neutron-lean reactor follow in the ARTEMIS design: it is socially acceptable in views of radioactivity and fuel resources, and the cost of electricity appears to be cheap compared with that from a light water reactor. Critical physics and engineering issues for performing the ARTEMIS-L reactor are clarified. (author)

  6. Ferrimagnetic Tb-Fe Alloy Thin Films: Composition and Thickness Dependence of Magnetic Properties and All-Optical Switching

    Directory of Open Access Journals (Sweden)

    Birgit eHebler

    2016-02-01

    Full Text Available Ferrimagnetic rare earth - transition metal Tb-Fe alloy thin films exhibit a variety of different magnetic properties, which depends strongly on composition and temperature. In this study, first the influence of the film thickness (5 - 85 nm on the sample magnetic properties was investigated in a wide composition range between 15 at.% and 38 at.% of Tb. From our results, we find that the compensation point, remanent magnetization, and magnetic anisotropy of the Tb-Fe films depend not only on the composition but also on the thickness of the magnetic film up to a critical thickness of about 20-30 nm. Beyond this critical thickness, only slight changes in magnetic properties are observed. This behavior can be attributed to a growth-induced modification of the microstructure of the amorphous films, which affects the short range order. As a result, a more collinear alignment of the distributed magnetic moments of Tb along the out-of-plane direction with film thickness is obtained. This increasing contribution of the Tb sublattice magnetization to the total sample magnetization is equivalent to a sample becoming richer in Tb and can be referred to as an effective composition. Furthermore, the possibility of all-optical switching, where the magnetization orientation of Tb-Fe can be reversed solely by circularly polarized laser pulses, was analyzed for a broad range of compositions and film thicknesses and correlated to the underlying magnetic properties.

  7. Compression of thick laminated composite beams with initial impact-like damage

    Science.gov (United States)

    Breivik, N. L.; Guerdal, Z.; Griffin, O. H., Jr.

    1992-01-01

    While the study of compression after impact of laminated composites has been under consideration for many years, the complexity of the damage initiated by low velocity impact has not lent itself to simple predictive models for compression strength. The damage modes due to non-penetrating, low velocity impact by large diameter objects can be simulated using quasi-static three-point bending. The resulting damage modes are less coupled and more easily characterized than actual impact damage modes. This study includes the compression testing of specimens with well documented initial damage states obtained from three-point bend testing. Compression strengths and failure modes were obtained for quasi-isotropic stacking sequences from 0.24 to 1.1 inches thick with both grouped and interspersed ply stacking. Initial damage prior to compression testing was divided into four classifications based on the type, extent, and location of the damage. These classifications are multiple through-thickness delaminations, isolated delamination, damage near the surface, and matrix cracks. Specimens from each classification were compared to specimens tested without initial damage in order to determine the effects of the initial damage on the final compression strength and failure modes. A finite element analysis was used to aid in the understanding and explanation of the experimental results.

  8. Influence of increment thickness on radiant energy and microhardness of bulk-fill resin composites.

    Science.gov (United States)

    Karacolak, Gamze; Turkun, L Sebnem; Boyacioglu, Hayal; Ferracane, Jack L

    2018-03-30

    Determining the energy transferred at the bottom of eleven bulk-fill resin composites, comparing top and bottom microhardness's and evaluating the correlation between microhardness and radiant energy were aimed. Samples were placed over the bottom sensor of a visible light transmission spectrophotometer and polymerized for 20 s. The bottom and top Knoop microhardness were measured. Paired t-test and correlation analysis were used for statistics (p≤0.05). In all groups, the bottom radiant energy decreased significantly with increasing thickness. For groups of Aura 2 mm, X-tra Fil 2 and 4 mm, SDR 2 and 4 mm, X-tra Base 2 mm no significant difference was found between top and bottom microhardness. For the bottom levels of Aura, X-tra Fil, Filtek Bulk-Fill Posterior, SDR, X-tra Base groups no significant difference was found between the microhardness's of 2 and 4 mm thicknesses. For X-tra Fil, Tetric Evo Ceram Bulk-Fill, Filtek Bulk-Fill Flowable and Z100 groups radiant energy affected positively the microhardness.

  9. Crossover from negative to positive magnetoresistance in superconductor/ferromagnet composites thick films

    Energy Technology Data Exchange (ETDEWEB)

    Paredes, O. [Centro de Materiales, Facultad de Ingenieria, Universidad de Narino, Ciudad Universitaria Torobajo, Pasto (Colombia); Baca, E. [Grupo de Ingenieria de Nuevos Materiales, Departamento de Fisica, Universidad del Valle, A.A. 25360 Cali (Colombia); Fuchs, D. [Karlsruhe Institute of Technology, Institut fuer Festkoerperphysik, P.O. Box 3640, Karlsruhe (Germany); Moran, O., E-mail: omoranc@unal.edu.c [Laboratorio de Materiales Ceramicos y Vitreos, Departamento de Fisica, Universidad Nacional de Colombia, Sede Medellin, A.A. 568 Medellin (Colombia)

    2010-11-15

    Thick films of ((Bi, Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x}){sub 0.95}/(LaSr{sub 0.7}Mn{sub 0.3}O{sub 3}){sub 0.05} [(Bi-2223){sub 0.95}(LSMO){sub 0.05}] composites were fabricated on (0 0 1)-oriented LaAlO{sub 3} substrates by a simple melting-quenching-annealing method and their structural, morphological and magnetoelectrical properties carefully studied. Analysis of the X-ray diffraction patterns suggested a highly oriented growth along the c-axis of LSMO. This preferred orientation, with the crystal c-axis being perpendicular to the plane of the substrate, was considered to be indicative of a textured growth mode. Electrical and magnetic measurements showed the presence of ferromagnetism and superconductivity in the composite at temperatures above room temperature and below T{approx}50 K, respectively. A clear crossover from negative to positive magnetoresistance was observed at {approx}80 K in a magnetic field as strong as 5 T.

  10. Oxygen inhibition layer of composite resins: effects of layer thickness and surface layer treatment on the interlayer bond strength.

    Science.gov (United States)

    Bijelic-Donova, Jasmina; Garoushi, Sufyan; Lassila, Lippo V J; Vallittu, Pekka K

    2015-02-01

    An oxygen inhibition layer develops on surfaces exposed to air during polymerization of particulate filling composite. This study assessed the thickness of the oxygen inhibition layer of short-fiber-reinforced composite in comparison with conventional particulate filling composites. The effect of an oxygen inhibition layer on the shear bond strength of incrementally placed particulate filling composite layers was also evaluated. Four different restorative composites were selected: everX Posterior (a short-fiber-reinforced composite), Z250, SupremeXT, and Silorane. All composites were evaluated regarding the thickness of the oxygen inhibition layer and for shear bond strength. An equal amount of each composite was polymerized in air between two glass plates and the thickness of the oxygen inhibition layer was measured using a stereomicroscope. Cylindrical-shaped specimens were prepared for measurement of shear bond strength by placing incrementally two layers of the same composite material. Before applying the second composite layer, the first increment's bonding site was treated as follows: grinding with 1,000-grit silicon-carbide (SiC) abrasive paper, or treatment with ethanol or with water-spray. The inhibition depth was lowest (11.6 μm) for water-sprayed Silorane and greatest (22.9 μm) for the water-sprayed short-fiber-reinforced composite. The shear bond strength ranged from 5.8 MPa (ground Silorane) to 36.4 MPa (water-sprayed SupremeXT). The presence of an oxygen inhibition layer enhanced the interlayer shear bond strength of all investigated materials, but its absence resulted in cohesive and mixed failures only with the short-fiber-reinforced composite. Thus, more durable adhesion with short-fiber-reinforced composite is expected. © 2014 Eur J Oral Sci.

  11. SiC fiber and yttria-stabilized zirconia composite thick thermal barrier coatings fabricated by plasma spray

    Science.gov (United States)

    Ma, Rongbin; Cheng, Xudong; Ye, Weiping

    2015-12-01

    Approximately 4 mm-thick SiC fiber/yttria-stabilized zirconia (YSZ) composite thermal barrier coatings (TBCs) were prepared by atmospheric plasma spray (APS). The composite coatings have a 'reinforced concrete frame structure', which can protect the coating from failure caused by increasing thickness of coating. The SiC fiber plays an important role in reducing the residual stress level of the composite coatings. The thermal conductivity (TC) value of the composite coatings is 0.632 W/m K, which is about 50% reduction compared to that of typical APS YSZ TBCs. And the composite coatings have higher fracture toughness and better thermal shock resistance than the YSZ TBCs.

  12. Through-thickness thermal conductivity enhancement of graphite film/epoxy composite via short duration acidizing modification

    Science.gov (United States)

    Wang, Han; Wang, Shaokai; Lu, Weibang; Li, Min; Gu, Yizhou; Zhang, Yongyi; Zhang, Zuoguang

    2018-06-01

    Graphite films have excellent in-plane thermal conductivity but extremely low through-thickness thermal conductivity because of their intrinsic inter-layer spaces. To improve the inter-layer heat transfer of graphite films, we developed a simple interfacial modification with a short duration mixed-acid treatment. The effects of the mixture ratio of sulfuric and nitric acids and treatment time on the through-thickness thermal properties of graphite films were studied. The modification increased the through-thickness thermal conductivity by 27% and 42% for the graphite film and its composite, respectively. X-ray photoelectron spectroscopy, X-ray powder diffraction, and scanning electron microscopy results indicated that the acidification process had two competing effects: the positive contribution made by the enhanced interaction between the graphite layers induced by the functional groups and the negative effect from the destruction of the graphite layers. As a result, an optimal acidification method was found to be sulfuric/nitric acid treatment with a mixture ratio of 3:1 for 15 min. The resultant through-thickness thermal conductivity of the graphite film could be improved to 0.674 W/mK, and the corresponding graphite/epoxy composite shows a through-thickness thermal conductivity of 0.587 W/mK. This method can be directly used for graphite films and their composite fabrication to improve through-thickness thermal conductivity.

  13. Roundness and taper of holes during drilling composites of various thickness by HSS drill bit under dry condition

    Science.gov (United States)

    Sakib, M. S.; Rahman, Motiur; Ferdous, M.; Dhar, N. R.

    2017-12-01

    Polymer Matrix Composites are extending a wide range of applications in aviation in recent eras because of their better economics, well established processing, high temperature properties, high resistance to corrosion and fatigue. Directional properties of composites are dependent on the fibre orientation. Composites being anisotropic in nature are difficult to drill and machining and tooling of the composites remained a great challenge over time. This paper addresses the issues of various machining problems such as delamination, fibre pull-out, cracks on varying drilling parameters like feed rate and drilling speed. Experimental drilling was carried out on Fibre Reinforced Plastic composites with HSS drill bit. Results reveal that as the number of holes increases the entry and exit diameter and tapper of holes vary and also varying composite thickness results in a difference in hole roundness and tapper. This experiment summarizes that for achieving acceptable tool life and hole quality demands a drill designed with composites.

  14. A novel asymptotic expansion homogenization analysis for 3-D composite with relieved periodicity in the thickness direction

    KAUST Repository

    Nasution, Muhammad Ridlo Erdata

    2014-06-01

    A new asymptotic expansion homogenization analysis is proposed to analyze 3-D composite in which thermomechanical and finite thickness effects are considered. Finite thickness effect is captured by relieving periodic boundary condition at the top and bottom of unit-cell surfaces. The mathematical treatment yields that only 2-D periodicity (i.e. in in-plane directions) is taken into account. A unit-cell representing the whole thickness of 3-D composite is built to facilitate the present method. The equivalent in-plane thermomechanical properties of 3-D orthogonal interlock composites are calculated by present method, and the results are compared with those obtained by standard homogenization method (with 3-D periodicity). Young\\'s modulus and Poisson\\'s ratio obtained by present method are also compared with experiments whereby a good agreement is particularly found for the Young\\'s modulus. Localization analysis is carried out to evaluate the stress responses within the unit-cell of 3-D composites for two cases: thermal and biaxial tensile loading. Standard finite element (FE) analysis is also performed to validate the stress responses obtained by localization analysis. It is found that present method results are in a good agreement with standard FE analysis. This fact emphasizes that relieving periodicity in the thickness direction is necessary to accurately simulate the real free-traction condition in 3-D composite. © 2014 Elsevier Ltd.

  15. A novel asymptotic expansion homogenization analysis for 3-D composite with relieved periodicity in the thickness direction

    KAUST Repository

    Nasution, Muhammad Ridlo Erdata; Watanabe, Naoyuki; Kondo, Atsushi; Yudhanto, Arief

    2014-01-01

    A new asymptotic expansion homogenization analysis is proposed to analyze 3-D composite in which thermomechanical and finite thickness effects are considered. Finite thickness effect is captured by relieving periodic boundary condition at the top and bottom of unit-cell surfaces. The mathematical treatment yields that only 2-D periodicity (i.e. in in-plane directions) is taken into account. A unit-cell representing the whole thickness of 3-D composite is built to facilitate the present method. The equivalent in-plane thermomechanical properties of 3-D orthogonal interlock composites are calculated by present method, and the results are compared with those obtained by standard homogenization method (with 3-D periodicity). Young's modulus and Poisson's ratio obtained by present method are also compared with experiments whereby a good agreement is particularly found for the Young's modulus. Localization analysis is carried out to evaluate the stress responses within the unit-cell of 3-D composites for two cases: thermal and biaxial tensile loading. Standard finite element (FE) analysis is also performed to validate the stress responses obtained by localization analysis. It is found that present method results are in a good agreement with standard FE analysis. This fact emphasizes that relieving periodicity in the thickness direction is necessary to accurately simulate the real free-traction condition in 3-D composite. © 2014 Elsevier Ltd.

  16. FRC plasma studies on the FRX-L plasma injector for MTF

    International Nuclear Information System (INIS)

    Wurden, G.A.; Intrator, T.P.; Zhang, S.Y.; Furno, I.G.; Hsu, S.C.; Park, J.Y.; Kirkpatrick, R.; Renneke, R.M.; Schoenberg, K.F.; Taccetti, M.J.; Tuszewski, M.G.; Waganaar, W.J.; Zhehui Wang; Siemon, R.E.; Degnan, J.H.; Gale, D.G.; Grabowski, C.; Ruden, E.L.; Sommars, W.; Frese, M.H.; Coffey, S.; Craddock, G.; Frese, S.D.; Roderick, N.F.

    2005-01-01

    To demonstrate the physics basis for Magnetized Target Fusion (MTF), we have designed a field reversed configuration (FRC) target plasma to ultimately be compressed within an imploding metal flux conserver (liner). This new, high energy density FRC device, named FRX-L, is operating at Los Alamos as a compact 'theta-pinch' formation FRC. The system capability includes a 0.5 T bias field, 70 kV 250 kHz ringing pre-ionization, and a 1.5 MA, 200 kJ main-theta-coil bank. We show FRC data with plasma parameters approaching the desired MTF requirements, examples of substantial Ohmic heating from magnetic flux annihilation, and measurements of plasma anomalous resistivity. Improvements are underway to reduce the main bank crowbar ringing, which will increase the trapped flux in the FRC. A prototype deformable flux-conserving liner with large entrance holes to accept an FRC has also been designed with MACH2 (2-D MHD modelling code) and successfully imploded at Kirtland Air Force Base on the Shiva Star pulsed power facility. (author)

  17. Hybrid Carbon-Glass Fiber/Toughened Epoxy Thick Composite Joints Subject to Drop-Weight and Ballistic Impacts

    National Research Council Canada - National Science Library

    Liaw, Benjamin; Delale, Feridun

    2007-01-01

    ... No. DAAD19-02-R-0010 to conduct research on hybrid carbon-S2 glass fiber/toughened epoxy thick-section, hybrid interwoven composite joints subject to drop-weight and ballistic impacts. Dr. Basavaraju B. Raju of U.S...

  18. The Effect of Composite Thickness on the Stress Distribution Pattern of Restored Premolar Teeth with Cusp Reduction.

    Science.gov (United States)

    Panahandeh, Narges; Torabzadeh, Hassan; Ziaee, Nargess; Mahdian, Mina; Tootiaee, Bahman; Ghasemi, Amir

    2017-07-01

    Different thicknesses of restorative material can alter the stress distribution pattern in remaining tooth structure. The assumption is that a thicker composite restoration will induce a higher fracture resistance. Therefore, the present study evaluated the effect of composite thickness on stress distribution in a restored premolar with cusp reduction. A 3D solid model of a maxillary second premolar was prepared and meshed. MOD cavities were designed with different cusp reduction thicknesses (0, 0.5, 1, 1.5, 2.5 mm). Cavities were restored with Valux Plus composite. They were loaded with 200 N force on the occlusal surface in the direction of the long axis. Von Mises stresses were evaluated with Abaqus software. Stress increased from occlusal to gingival and was maximum in the cervical region. The stressed area in the palatal cusp was more than that of the buccal cusp. Increasing the thickness of composite altered the shear stress to compressive stress in the occlusal area of the teeth. The model with 2.5 mm cusp reduction exhibited the most even stress distribution. © 2015 by the American College of Prosthodontists.

  19. Chairside fabricated fiber-reinforced composite fixed partial denture

    Directory of Open Access Journals (Sweden)

    Sufyan Garoushi

    2007-01-01

    Full Text Available The advances in the materials and techniques for adhesive dentistry have allowed the development of non-invasive or minimally invasive approaches for replacing a missing tooth in those clinical situations when conservation of adjacent teeth is needed. Good mechanical and cosmetic/aesthetic properties of fiber-reinforced composite (FRC, with good bonding properties with composite resin cement and veneering composite are needed in FRC devices. Some recent studies have shown that adhesives of composite resins and luting cements allow diffusion of the adhesives to the FRC framework of the bridges. By this so-called interdiffusion bonding is formed [1]. FRC bridges can be made in dental laboratories or chairside. This article describes a clinical case of chairside (directly made FRC Bridge, which was used according to the principles of minimal invasive approach. Treatment was performed by Professor Vallittu from the University of Turku, Finland.

  20. Film-thickness and composition dependence of epitaxial thin-film PZT-based

    NARCIS (Netherlands)

    Nguyen, Duc Minh; Dekkers, Jan M.; Vu, Hung Ngoc; Rijnders, Augustinus J.H.M.

    2013-01-01

    The transverse piezoelectric coefficient e31,f and mass-sensitivity were measured on piezoelectric cantilevers based on epitaxial PZT thin-films with film-thicknesses ranging from 100 to 2000 nm. The highest values of e31,f and mass-sensitivity were observed at a film thickness of 500–750 nm, while

  1. Overview of C-2U FRC Experimental Program and Plans for C-2W

    Science.gov (United States)

    Gota, H.; Binderbauer, M. W.; Tajima, T.; Putvinski, S.; Tuszewski, M.; Dettrick, S.; Korepanov, S.; Smirnov, A.; Thompson, M. C.; Yang, X.; Cappello, M.; Ivanov, A. A.; TAE Team

    2016-10-01

    Tri Alpha Energy's experimental program has been focused on a demonstration of reliable field-reversed configuration (FRC) formation and sustainment, driven by fast ions via high-power neutral-beam (NB) injection. The world's largest compact-toroid experimental devices, C-2 and C-2U, have successfully produced a well-stabilized, sustainable FRC plasma state with NB injection (input power, PNB 10 + MW; 15 keV hydrogen) and end-on coaxial plasma guns. Remarkable improvements in confinement and stability of FRC plasmas have led to further improved fast-ion build up; thereby, an advanced beam-driven FRC state has been produced and sustained for up to 5 + ms (longer than all characteristic system time scales), only limited by hardware and electric supply constraints such as NB and plasma-gun power supplies. To further improve the FRC performance the C-2U device is being replaced by C-2W featuring higher injected NB power, longer pulse duration as well as enhanced edge-biasing systems and substantially upgraded divertors. Main C-2U experimental results and key features of C-2W will be presented. Tri Alpha Energy, Inc.

  2. Formation and sustainment of field reversed configuration (FRC) plasmas by spheromak merging and neutral beam injection

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Masaaki [Princeton Plasma Physics Laboratory, Princeton University Princeton, New Jersey USA (United States)

    2016-03-25

    This paper briefly reviews a compact toroid reactor concept that addresses critical issues for forming, stabilizing and sustaining a field reversed configuration (FRC) with the use of plasma merging, plasma shaping, conducting shells, neutral beam injection (NBI). In this concept, an FRC plasma is generated by the merging of counter-helicity spheromaks produced by inductive discharges and sustained by the use of neutral beam injection (NBI). Plasma shaping, conducting shells, and the NBI would provide stabilization to global MHD modes. Although a specific FRC reactor design is outside the scope of the present paper, an example of a promising FRC reactor program is summarized based on the previously developed SPIRIT (Self-organized Plasmas by Induction, Reconnection and Injection Techniques) concept in order to connect this concept to the recently achieved the High Performance FRC plasmas obtained by Tri Alpha Energy [Binderbauer et al, Phys. Plasmas 22,056110, (2015)]. This paper includes a brief summary of the previous concept paper by M. Yamada et al, Plasma Fusion Res. 2, 004 (2007) and the recent experimental results from MRX.

  3. Development of a metrology method for composition and thickness of barium strontium titanate thin films

    International Nuclear Information System (INIS)

    Remmel, Thomas; Werho, Dennis; Liu, Ran; Chu, Peir

    1998-01-01

    Thin films of barium strontium titanate (BST) are being investigated as the charge storage dielectric in advanced memory devices, due to their promise for high dielectric constant. Since the capacitance of BST films is a function of both stoichiometry and thickness, implementation into manufacturing requires precise metrology methods to monitor both of these properties. This is no small challenge, considering the BST film thicknesses are 60 nm or less. A metrology method was developed based on X-ray Fluorescence and applied to the measurement of stoichiometry and thickness of BST thin films in a variety of applications

  4. 3D-WOVEN FIBER-REINFORCED COMPOSITE FOR CAD/CAM DENTAL APPLICATION.

    Science.gov (United States)

    Petersen, Richard; Liu, Perng-Ru

    2016-05-01

    Three-dimensional (3D)-woven noncrimp fiber-reinforced composite (FRC) was tested for mechanical properties in the two principal directions of the main XY plane and compared to different Computer-Aided-Design/Computer-Aided-Machining (CAD/CAM) Dental Materials. The Dental Materials included ceramic with Vitablock Mark II®, ProCAD®, InCeram® Spinel, InCeram® Alumina and InCeram® Zirconia in addition to a resin-based 3M Corp. Paradigm® particulate-filled composite. Alternate material controls included Coors 300 Alumina Ceramic and a tungsten carbide 22% cobalt cermet. The 3D-woven FRC was vacuum assisted resin transfer molding processed as a one-depth-thickness ~19-mm preform with a vinyl-ester resin and cut into blocks similar to the commercial CAD/CAM Dental Materials. Mechanical test samples prepared for a flexural three-point span length of 10.0 mm were sectioned for minimum-depth cuts to compare machinability and fracture resistance between groups. 3D-woven FRC improved mechanical properties with significant statistical differences over all CAD/CAM Dental Materials and Coors Alumina Ceramic for flexural strength (p<0.001), resilience (p<0.05), work of fracture (p<0.001), strain energy release (p<0.05), critical stress intensity factor (p<0.001) and strain (p<0.001).

  5. Investigation of a carbon fiber/epoxy prepreg curing behavior for thick composite materials production: An industrial case-study

    Science.gov (United States)

    Giorgini, Loris; Mazzocchetti, Laura; Minak, Giangiacomo; Dolcini, Enrico

    2012-07-01

    A case-study is presented, in cooperation with RI-BA Composites srl, where the industrial production of a thick part for primary structural application is analysed. The final product is a bulk carbon fiber reinforced object characterized by great dimensions, with thickness ranging between 10mm and 35mm and obtained by Hand-Lay-Up of prepregs. The study shows that prepregs age along the time required for the process work up. Moreover, the isothermal curing investigation of the prepreg used in the production gives some useful hint for the design of a new thermal curing cycle, in order to avoid exotherm problems along the thickness of the object. The effect of the applied curing cycle on thermal properties of the object are reported.

  6. Nuchal Skinfold Thickness: A Novel Parameter for Assessment of Body Composition in Childhood Craniopharyngioma

    Science.gov (United States)

    Sterkenburg, Anthe S.; Hoffmann, Anika; Reichel, Julia; Lohle, Kristin; Eveslage, Maria; Warmuth-Metz, Monika

    2016-01-01

    Context: Hypothalamic obesity, cardiovascular disease (CVD), and relapse/progression have a major impact on prognosis in childhood-onset craniopharyngioma (CP). We analyzed nuchal skinfold thickness (NST) on magnetic resonance imaging performed for follow-up monitoring as a novel parameter for body composition (BC) and CVD in CP. Objective: The objective of the study was to identify the association of NST with body mass index (BMI), waist to height ratio (WHtR), functional capacity, and blood pressure (BP) in CP and controls. Design: This was a cross-sectional and longitudinal prospective study in CP patients. Setting: The study was conducted at HIT-Endo, KRANIOPHARYNGEOM 2000/2007. Patients: Participants included 94 CP patients and 75 controls. Interventions: There were no interventions. Main Outcome Measures: Association of NST with BC and BP in 43 CP and 43 controls was measured. Results: NST correlated with BMI SD score (SDS; r = 0.78; P < .001; n = 169) and WHtR (r = 0.85; P < .001; n = 86) in the total cohort and CP patients (NST-BMI SDS: r = 0.77, P < .001, n = 94); NST-WHtR: r = 0.835, P < .001, n=43) and controls (NST-BMI SDS: r = 0.792, P < .001, n = 75; NST-WHtR: r = 0.671, P < .001, n = 43). In CP, systolic BP correlated with NST (r = 0.575, P < .001), BMI SDS (r = 0.434, P = .004), and WHtR (r = 0.386, P = .011). Similar results were observed for diastolic BP in CP. In multivariate analyses, NST had a predictive value for hypertension in postpubertal CP and controls (odds ratio 6.98, 95% confidence interval [1.65, 29.5], P = .008). During a longitudinal follow-up, changes in NST correlated with changes in BMI SDS (P < .001) and WHtR (P = .01) but not with changes in BP and functional capacity. Conclusions: Because monitoring of magnetic resonance imaging and BC is essential for follow-up in CP, NST could serve as a novel and clinically relevant parameter for longitudinal assessment of BC and CVD risk in CP. PMID:27680877

  7. Accelerated Fatigue Resistance of Thick CAD/CAM Composite Resin Overlays Bonded with Light- and Dual-polymerizing Luting Resins.

    Science.gov (United States)

    Goldberg, Jack; Güth, Jan-Frederik; Magne, Pascal

    To evaluate the accelerated fatigue resistance of thick CAD/CAM composite resin overlays luted with three different bonding methods. Forty-five sound human second mandibular molars were organized and distributed into three experimental groups. All teeth were restored with a 5-mm-thick CAD/CAM composite resin overlay. Group A: immediate dentin sealing (IDS) with Optibond FL and luted with light-polymerizing composite (Herculite XRV). Group B: IDS with Optibond FL and luted with dual-polymerizing composite (Nexus 3). Group C: direct luting with Optibond FL and dual-polymerizing composite (Nexus 3). Masticatory forces at a frequency of 5 Hz were simulated using closed-loop servo-hydraulics and forces starting with a load of 200 N for 5000 cycles, followed by steps of 400, 600, 800, 1000, 1200 and 1400 N for a maximum of 30,000 cycles. Each step was applied through a flat steel cylinder at a 45-degree angle under submerged conditions. The fatigue test generated one failure in group A, three failures in group B, and no failures in group C. The survival table analysis for the fatigue test did not demonstrate any significant difference between the groups (p = 0.154). The specimens that survived the fatigue test were set up for the load-to-failure test with a limit of 4600 N. The survival table analysis for the load-to-failure test demonstrates an average failure load of 3495.20 N with survival of four specimens in group A, an average failure load of 4103.60 N with survival of six specimens in group B, and an average failure load of 4075.33 N with survival of nine specimens in group C. Pairwise comparisons revealed no significant differences (p composites in combination with IDS are not contraindicated with thick restorations.

  8. Analysis of a hybrid balanced laminate as a structural material for thick composite beams with axial stiffeners

    Energy Technology Data Exchange (ETDEWEB)

    Modak, Partha; Hossain, M. Jamil, E-mail: jamil917@gmail.com; Ahmed, S. Reaz [Department of Mechanical Engineering, Bangladesh University of Engineering and Technology, Dhaka 1000 (Bangladesh)

    2016-07-12

    An accurate stress analysis has been carried out to investigate the suitability of a hybrid balanced laminate as a structural material for thick composite beams with axial stiffeners. Three different balanced laminates composed of dissimilar ply material as well as fiber orientations are considered for a thick beam on simple supports with stiffened lateral ends. A displacement potential based elasticity approach is used to obtain the numerical solution of the corresponding elastic fields. The overall laminate stresses as well as individual ply stresses are analysed mainly in the perspective of laminate hybridization. Both the fiber material and ply angle of individual laminas are found to play dominant roles in defining the design stresses of the present composite beam.

  9. Ultrathin Composite Polymeric Membranes for CO2 /N2 Separation with Minimum Thickness and High CO2 Permeance.

    Science.gov (United States)

    Benito, Javier; Sánchez-Laínez, Javier; Zornoza, Beatriz; Martín, Santiago; Carta, Mariolino; Malpass-Evans, Richard; Téllez, Carlos; McKeown, Neil B; Coronas, Joaquín; Gascón, Ignacio

    2017-10-23

    The use of ultrathin films as selective layers in composite membranes offers significant advantages in gas separation for increasing productivity while reducing the membrane size and energy costs. In this contribution, composite membranes have been obtained by the successive deposition of approximately 1 nm thick monolayers of a polymer of intrinsic microporosity (PIM) on top of dense membranes of the ultra-permeable poly[1-(trimethylsilyl)-1-propyne] (PTMSP). The ultrathin PIM films (30 nm in thickness) demonstrate CO 2 permeance up to seven times higher than dense PIM membranes using only 0.04 % of the mass of PIM without a significant decrease in CO 2 /N 2 selectivity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Dynamic tensile stress–strain characteristics of carbon/epoxy laminated composites in through-thickness direction

    Directory of Open Access Journals (Sweden)

    Nakai Kenji

    2015-01-01

    Full Text Available The effect of strain rate up to approximately ε̇ = 102/s on the tensile stress–strain properties of unidirectional and cross-ply carbon/epoxy laminated composites in the through-thickness direction is investigated. Waisted cylindrical specimens machined out of the laminated composites in the through-thickness direction are used in both static and dynamic tests. The dynamic tensile stress–strain curves up to fracture are determined using the split Hopkinson bar (SHB. The low and intermediate strain-rate tensile stress–strain relations up to fracture are measured on an Instron 5500R testing machine. It is demonstrated that the ultimate tensile strength and absorbed energy up to fracture increase significantly, while the fracture strain decreases slightly with increasing strain rate. Macro- and micro-scopic examinations reveal a marked difference in the fracture surfaces between the static and dynamic tension specimens.

  11. Ballistic Simulation Method for Lithium Ion Batteries (BASIMLIB) Using Thick Shell Composites (TSC) in LS-DYNA

    Science.gov (United States)

    2016-08-04

    BAllistic SImulation Method for Lithium Ion Batteries (BASIMLIB) using Thick Shell Composites (TSC) in LS-DYNA Venkatesh Babu, Dr. Matt Castanier, Dr...and behavior of the cells through experimental and modeling at their crash worthiness laboratory • Most of the simulation work on the batteries are...at a single cell level and gap exists to simulate the batteries at their full pack capacity - Firstly, requires an enormous amount of computational

  12. Thick filament length and isoform composition determine self-organized contractile units in actomyosin bundles.

    Science.gov (United States)

    Thoresen, Todd; Lenz, Martin; Gardel, Margaret L

    2013-02-05

    Diverse myosin II isoforms regulate contractility of actomyosin bundles in disparate physiological processes by variations in both motor mechanochemistry and the extent to which motors are clustered into thick filaments. Although the role of mechanochemistry is well appreciated, the extent to which thick filament length regulates actomyosin contractility is unknown. Here, we study the contractility of minimal actomyosin bundles formed in vitro by mixtures of F-actin and thick filaments of nonmuscle, smooth, and skeletal muscle myosin isoforms with varied length. Diverse myosin II isoforms guide the self-organization of distinct contractile units within in vitro bundles with shortening rates similar to those of in vivo myofibrils and stress fibers. The tendency to form contractile units increases with the thick filament length, resulting in a bundle shortening rate proportional to the length of constituent myosin thick filament. We develop a model that describes our data, providing a framework in which to understand how diverse myosin II isoforms regulate the contractile behaviors of disordered actomyosin bundles found in muscle and nonmuscle cells. These experiments provide insight into physiological processes that use dynamic regulation of thick filament length, such as smooth muscle contraction. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  13. Hybrid carbon-glass fiber/toughened epoxy thick composites subject to drop-weight and ballistic impacts

    Science.gov (United States)

    Sevkat, Ercan

    The goals of this study are to investigate the low velocity and ballistic impact response of thick-section hybrid fiber composites at room temperature. Plain-woven S2-Glass and IM7 Graphite fabrics are chosen as fiber materials reinforcing the SC-79 epoxy. Four different types of composites consisting of alternating layers of glass and graphite woven fabric sheets are considered. Tensile tests are conducted using 98 KN (22 kip) MTS testing machine equipped with environmental chamber. Low-velocity impact tests are conducted using an Instron-Dynatup 8250 impact test machine equipped with an environmental chamber. Ballistic impact tests are performed using helium pressured high-speed gas-gun. Tensile tests results were used to define the material behavior of the hybrid and non-hybrid composites in Finite Element modeling. The low velocity and ballistic impact tests showed that hybrid composites performance was somewhere between non-hybrid woven composites. Using woven glass fabrics as outer skin improved the impact performance of woven graphite composite. However hybrid composites are prone to delamination especially between dissimilar layers. The ballistic limit velocity V50 hybrid composites were higher that of woven graphite composite and lower than that of woven glass composite. Both destructive cross-sectional micrographs and nondestructive ultrasonic techniques are used to evaluate the damage created by impact. The Finite Element code LS-DYNA is chosen to perform numerical simulations of low velocity and ballistic impact on thick-section hybrid composites. The damage progression in these composites shows anisotropic nonlinearity. The material model to describe this behavior is not available in LS-DYNA material library. Initially, linear orthotropic material with damage (Chan-Chan Model) is employed to simulate some of the experimental results. Then, user-defined material subroutine is incorporated into LS-DYNA to simulate the nonlinear behavior. The

  14. Influence of SiC coating thickness on mechanical properties of SiCf/SiC composite

    Science.gov (United States)

    Yu, Haijiao; Zhou, Xingui; Zhang, Wei; Peng, Huaxin; Zhang, Changrui

    2013-11-01

    Silicon carbide (SiC) coatings with varying thickness (ranging from 0.14 μm to 2.67 μm) were deposited onto the surfaces of Type KD-I SiC fibres with native carbonaceous surface using chemical vapour deposition (CVD) process. Then, two dimensional SiC fibre reinforced SiC matrix (2D SiCf/SiC) composites were fabricated using polymer infiltration and pyrolysis (PIP) process. Influences of the fibre coating thickness on mechanical properties of SiC fibre and SiCf/SiC composite were investigated using single-filament test and three-point bending test. The results indicated that flexural strength of the composites initially increased with the increasing CVD SiC coating thickness and reached a peak value of 363 MPa at the coating thickness of 0.34 μm. Further increase in the coating thickness led to a rapid decrease in the flexural strength of the composites. The bending modulus of composites showed a monotonic increase with increasing coating thickness. A chemical attack of hydrogen or other ions (e.g. a C-H group) on the surface of SiC fibres during the coating process, owing to the formation of volatile hydrogen, lead to an increment of the surface defects of the fibres. This was confirmed by Wang et al. [35] in their work on the SiC coating of the carbon fibre. In the present study, the existing ˜30 nm carbon on the surface of KD-I fibre [36] made the fibre easy to be attacked. Deposition of non-stoichiometric SiC, causing a decrease in strength. During the CVD process, a small amount of free silicon or carbon always existed [35]. The existence of free silicon, either disordered the structure of SiC and formed a new source of cracks or attacked the carbon on fibre surface resulting in properties degeneration of the KD-I fibre. The effect of residual stress. The different thermal expansion coefficient between KD-I SiC fibre and CVD SiC coating, which are 3 × 10-6 K-1 (RT ˜ 1000 °C) and 4.6 × 10-6 K-1 (RT ˜ 1000 °C), respectively, could cause residual stress

  15. Effect of composite resin polymerization modes on temperature rise in human dentin of different thicknesses: an in vitro study

    International Nuclear Information System (INIS)

    Baggio Aguiar, Flavio Henrique; Kanda Peres Barros, Gisele; Alves Nunes Leite Lima, Debora; Bovi Ambrosano, Glaucia Maria; Lovadino, Jose Roberto

    2006-01-01

    The aim of this in vitro study was to evaluate the effect of different polymerization modes on temperature rise in human dentin of different thicknesses, and to evaluate the relation between dentin thickness and temperature rise (TR). For this purpose, 60 specimens were assigned into 20 groups (n = 3): five polymerization modes (1-conventional; 2-soft-start; 3-high intensity; 4-ramp cure: progressive and high intensity; 5-high intensity with the tip of the light-curing unit at a distance of 1.3 cm for 10 s and the tip leaning on the sample) at four dentin thicknesses (0, 1, 2, 3 mm). During composite sample polymerization (2 mm), the temperature was measured by a digital laser thermometer (CMSS2000-SL/SKF). The statistical analyses were conducted by ANOVA (p = 0.05) and post-hoc Tukey's test. There were statistical differences of TR among polymerization modes and dentin thicknesses. The temperature rise was dependent on the polymerization mode and the dentin thickness: the thicker the dentin and the lower the polymerization mode energy, the lower the temperature rise

  16. Physically Gelled Room-Temperature Ionic Liquid-Based Composite Membranes for CO2/N-2 Separation: Effect of Composition and Thickness on Membrane Properties and Performance

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, PT; Voss, BA; Wiesenauer, EF; Gin, DL; Nobe, RD

    2013-07-03

    An aspartame-based, low molecular-weight organic gelator (LMOG) was used to form melt-infused and composite membranes with two different imidazolium-based room-temperature ionic liquids (RTILs) for CO2 separation from N-2. Previous work demonstrated that LMOGs can gel RTILs at low, loading levels, and this aspartame-based LMOG was selected because it has been reported to gel a large number of RTILs. The imidazolium-based RTILs were used because of their inherent good properties for CO2/light gas separations. Analysis of the resulting bulk RTIL/LMOG physical gels showed that these materials have high sol-gel transition temperatures (ca. 135 degrees C) suitable for flue gas applications. Gas permeabilities and burst pressure measurements of thick, melt infused membranes revealed a trade-off between high CO2 permeabilities and good mechanical stability as a function of the LMOG loading. Defect-free, composite membranes of the gelled RTILs were successfully fabricated by choosing an appropriate porous membrane support (hydrophobic PTFE) using a suitable coating technique (roller coating). The thicknesses of the applied composite gel layers ranged from 10.3 to 20.7 mu m, which represents an order of magnitude decrease in active layer thickness, compared to the original melt-infused gel RTIL membranes.

  17. A functional analysis of the formyl-coenzyme A (frc) gene from Lactobacillus reuteri 100-23C.

    Science.gov (United States)

    Kullin, B; Tannock, G W; Loach, D M; Kimura, K; Abratt, V R; Reid, S J

    2014-06-01

    To examine the role of the Lactobacillus reuteri 100-23C frc gene product in oxalate metabolism, host colonization and the acid stress response. Genes encoding putative formyl-CoA transferase (frc) and oxalyl-CoA decarboxylase (oxc) enzymes are present in the genome sequences of Lact. reuteri strains. Two strains isolated from humans harboured an IS200 insertion sequence in the frc ORF and a group 2 intron-associated transposase downstream of the frc gene, both of which were lacking in two strains of animal origin, which contained intact frc and oxc genes. An frc(-) insertional mutant of Lact. reuteri 100-23C was compared with the parent strain with respect to oxalate degradation, colonization of an RLF-mouse host model and growth in the presence of acids. Neither parent nor mutant degraded oxalate in vitro or in vivo. However, the parent outcompeted the frc(-) mutant in the mouse intestine during co-colonization and the frc(-) mutant showed a reduced growth rate in the presence of hydrochloric acid. Intact oxc and frc genes do not ensure oxalate degradation under the conditions tested. The frc gene product is important during host colonization and survival of acid stress by Lact. reuteri 100-23C. Oxalate metabolism by oxalate-degrading intestinal bacterial strains may be important in preventing urolithiasis and might lead to the derivation of probiotic products. To produce safe and efficacious probiotics, however, an understanding of the genetic characteristics of potential oxalate degraders must be obtained, together with knowledge of their functional ramifications. © 2014 The Society for Applied Microbiology.

  18. Computational study of the influence of mirror parameters on FRC (field-reversed configuration) equilibria:

    International Nuclear Information System (INIS)

    Fuentes, N.O.; Sakanaka, P.H.

    1990-01-01

    Field-reversed configuration equilibria are studied by solving the Grad-Shafranov equation. A multiple coil system (main coil and end mirrors) is considered to simulate the coil geometry of CNEA device. First results are presented for computed two-dimensional FRC equilibria produced varying the mirror coil current with two different mirror lenghts. (Author)

  19. Natural and Accelerated Bioremediation Research (NABIR) Field Research Center (FRC), Oak Ridge Tennessee

    International Nuclear Information System (INIS)

    Watson, David; Jardine, Philip; Gu, Baohua; Parker, Jack; Brandt, Craig; Holladay, Susan; Wolfe, Amy; Bogle, Mary Anna; Lowe, Kenneth; Hyder, Kirk

    2006-01-01

    The Field Research Center (FRC) in Oak Ridge (Fig. 1), Tennessee supports the U.S. Department of Energy's (DOE's) Environmental Remediation Sciences Program (ERSP) goal of understanding the complex physical, chemical, and biological properties of contaminated sites for new solutions to environmental remediation and long-term stewardship. In particular, the FRC provides the opportunity for researchers to conduct studies that promote the understanding of the processes that influence the transport and fate of subsurface contaminants, the effectiveness and long-term consequences of existing remediation options, and the development of improved remediation strategies. It offers a series of contaminated sites around the former S-3 Waste Disposal Ponds and uncontaminated sites in which investigators and students conduct field research or collect samples for laboratory analysis. FRC research also spurs the development of new and improved characterization and monitoring tools. Site specific knowledge gained from research conducted at the FRC also provides the DOE-Oak Ridge Office of Environmental Management (EM) the critical scientific knowledge needed to make cleanup decisions for the S-3 Ponds and other sites on the Oak Ridge Reservation (ORR)

  20. Natural and Accelerated Bioremediation Research (NABIR) Field Research Center (FRC) Management Plan

    Energy Technology Data Exchange (ETDEWEB)

    Watson, D.B.

    2002-02-28

    The Environmental Sciences Division at Oak Ridge National Laboratory has established a Field Research Center (FRC) to support the Natural and Accelerated Bioremediation Research (NABIR) Program on the U.S. Department of Energy (DOE) Oak Ridge Reservation in Oak Ridge, Tennessee for the DOE Headquarters Office of Biological and Environmental Research within the Office of Science.

  1. Effects of copolymer composition, film thickness, and solvent vapor annealing time on dewetting of ultrathin block copolymer films.

    Science.gov (United States)

    Huang, Changchun; Wen, Gangyao; Li, Jingdan; Wu, Tao; Wang, Lina; Xue, Feifei; Li, Hongfei; Shi, Tongfei

    2016-09-15

    Effects of copolymer composition, film thickness, and solvent vapor annealing time on dewetting of spin-coated polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) films (dewetting of the films with different thicknesses occur via the spinodal dewetting and the nucleation and growth mechanisms, respectively. The PS-b-PMMA films rupture into droplets which first coalesce into large ones to reduce the surface free energy. Then the large droplets rupture into small ones to increase the contact area between PMMA blocks and acetone molecules resulting from ultimate migration of PMMA blocks to droplet surface, which is a novel dewetting process observed in spin-coated films for the first time. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Effects of stitch density and stitch thread thickness on mode II delamination properties of Vectran stitched composites

    KAUST Repository

    Herwan, J.

    2014-11-01

    © Institute of Materials, Minerals and Mining 2014. Mode II delamination properties of Vectran stitched composites were investigated, and tabbed end notch flexural specimen testing was used to prevent premature failure. The effects of stitch density and stitch thread thickness were explored, and fibre compaction due to the stitching process was also verified. The results show that, in moderately stitched laminates (low stitch density), the improvement in GIIC was negligible. Crack bridging by the stitch threads at the crack zone were mostly compensated for the effect of fibre compaction, which reduced the GIIC values. Conversely, in densely stitched laminates (high stitch density), GIIC values were improved significantly (2·4 times higher than those of unstitched laminates). The effects of stitch thread thickness appeared to be negligible in moderately stitched laminates. For densely stitched laminates, thicker stitch thread (500 denier) possessed GIIC values that were 45·7% higher than thinner stitch thread (200 denier).

  3. Effects of stitch density and stitch thread thickness on mode II delamination properties of Vectran stitched composites

    KAUST Repository

    Herwan, J.; Kondo, A.; Morooka, S.; Watanabe, N.

    2014-01-01

    © Institute of Materials, Minerals and Mining 2014. Mode II delamination properties of Vectran stitched composites were investigated, and tabbed end notch flexural specimen testing was used to prevent premature failure. The effects of stitch density and stitch thread thickness were explored, and fibre compaction due to the stitching process was also verified. The results show that, in moderately stitched laminates (low stitch density), the improvement in GIIC was negligible. Crack bridging by the stitch threads at the crack zone were mostly compensated for the effect of fibre compaction, which reduced the GIIC values. Conversely, in densely stitched laminates (high stitch density), GIIC values were improved significantly (2·4 times higher than those of unstitched laminates). The effects of stitch thread thickness appeared to be negligible in moderately stitched laminates. For densely stitched laminates, thicker stitch thread (500 denier) possessed GIIC values that were 45·7% higher than thinner stitch thread (200 denier).

  4. Thickness optimization of fiber reinforced laminated composites using the discrete material optimization method

    DEFF Research Database (Denmark)

    Sørensen, Søren Nørgaard; Lund, Erik

    2012-01-01

    This work concerns a novel large-scale multi-material topology optimization method for simultaneous determination of the optimum variable integer thickness and fiber orientation throughout laminate structures with fixed outer geometries while adhering to certain manufacturing constraints....... The conceptual combinatorial/integer problem is relaxed to a continuous problem and solved on basis of the so-called Discrete Material Optimization method, explicitly including the manufacturing constraints as linear constraints....

  5. An Improved Design Methodology for Modeling Thick-Section Composite Structures Using a Multiscale Approach

    Science.gov (United States)

    2012-09-01

    case study no. 2. The multiaxial loading combined with XZ and YZ Poisson ratio effects contributes to strains in the Z-direction of the sample. The...E. A Continuum Damage Model for Fiber Reinforced Laminates Based on Ply Failure Mechanisms, Composite Structures. Fifteenth International...output parameters, stiffness ratios , to analyze the nonlinear response and progressive failure of the composite structure is developed. These new

  6. Composite Thickness Optimization of Offshore Wind Turbine Blade with Fixed outer Geometry

    DEFF Research Database (Denmark)

    Sjølund, Jonas Heidemann; Lund, Erik

    2017-01-01

    With the objective of mass minimization, a 73-m offshore wind turbine blade is optimized using a gradient based approach on a Finite Element (FE) model. Constant loads and a fixed outer geometry are assumed. Plies of the same material and same orientation are grouped together in plygroups. The th....... The thicknesses of the plygroups are chosen as design variables. Manufacturing constraints such as ply-drops are taken into account using linear constraints. Structural constraints include buckling, tip displacement and max. strain failure indices....

  7. Antifouling Properties of Fluoropolymer Brushes toward Organic Polymers: The Influence of Composition, Thickness, Brush Architecture, and Annealing.

    Science.gov (United States)

    Wang, Zhanhua; Zuilhof, Han

    2016-07-05

    Fluoropolymer brushes are widely used to prevent nonspecific adsorption of commercial polymeric or biological materials due to their strongly hydrophobic character. Herein, a series of fluoropolymer brushes with different compositions, thicknesses and molecular architectures was prepared via surface-initiated atom transfer radical polymerization (ATRP). Subsequently, the antifouling properties of these fluoropolymer brushes against organic polymers were studied in detail using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) measurements and polystyrene as a representative fouling polymer. Among all of the molecular architectures studied, homopolymerized methacrylate-based fluoropolymer brushes (PMAF17) show the best antifouling properties. Annealing the fluoropolymer brushes improves the antifouling property dramatically due to the reregulated surface composition. These fluoropolymer brushes can be combined with, e.g., micro- and nanostructuring and other advanced materials properties to yield even better long-term antifouling behavior under harsh environments.

  8. Effects of composition and layer thickness of a butyl acrylate/acrylic acid copolymer on the adhesion properties

    Energy Technology Data Exchange (ETDEWEB)

    Ghim, Deoukchen; Kim, Jung Hyeun [University of Seoul, Seoul (Korea, Republic of)

    2016-02-15

    Acrylic pressure-sensitive adhesives are synthesized by solution copolymerization using n-butyl acrylate and acrylic acid (AA) in ethyl acetate anhydrous. The copolymer composition is controlled for good adhesive properties by varying AA content. The monomer conversion is measured by the gravimetric method and FTIR technique. The adhesive layer thickness is measured by scanning electron microscopy, and the adhesive properties are evaluated with loop tack, 180 .deg. peel, and holding time measurements. The peel force increases with increasing the AA content up to 3 wt% and decreases at the AA content higher than 3 wt%, but the tack force decreases with increasing the AA content. The holding time increases with increasing the AA content, and it shows a similar trend with the T{sub g} of adhesives. The increase of layer thickness improves tack and peel forces, but it weakens the holding power. A tape thickness of about 20 μm shows well-balanced properties at 3 wt% AA content in the acrylic copolymer system.

  9. Effects of composition and layer thickness of a butyl acrylate/acrylic acid copolymer on the adhesion properties

    International Nuclear Information System (INIS)

    Ghim, Deoukchen; Kim, Jung Hyeun

    2016-01-01

    Acrylic pressure-sensitive adhesives are synthesized by solution copolymerization using n-butyl acrylate and acrylic acid (AA) in ethyl acetate anhydrous. The copolymer composition is controlled for good adhesive properties by varying AA content. The monomer conversion is measured by the gravimetric method and FTIR technique. The adhesive layer thickness is measured by scanning electron microscopy, and the adhesive properties are evaluated with loop tack, 180 .deg. peel, and holding time measurements. The peel force increases with increasing the AA content up to 3 wt% and decreases at the AA content higher than 3 wt%, but the tack force decreases with increasing the AA content. The holding time increases with increasing the AA content, and it shows a similar trend with the T g of adhesives. The increase of layer thickness improves tack and peel forces, but it weakens the holding power. A tape thickness of about 20 μm shows well-balanced properties at 3 wt% AA content in the acrylic copolymer system.

  10. Meshless Solution of the Problem on the Static Behavior of Thin and Thick Laminated Composite Beams

    Science.gov (United States)

    Xiang, S.; Kang, G. W.

    2018-03-01

    For the first time, the static behavior of laminated composite beams is analyzed using the meshless collocation method based on a thin-plate-spline radial basis function. In the approximation of a partial differential equation by using a radial basis function, the shape parameter has an important role in ensuring the numerical accuracy. The choice of a shape parameter in the thin plate spline radial basis function is easier than in other radial basis functions. The governing differential equations are derived based on Reddy's third-order shear deformation theory. Numerical results are obtained for symmetric cross-ply laminated composite beams with simple-simple and cantilever boundary conditions under a uniform load. The results found are compared with available published ones and demonstrate the accuracy of the present method.

  11. The Development of High Transition Temperature Superconducting Ceramic Thick Films and Wire Composites

    Science.gov (United States)

    1991-12-02

    number of protein or sugar agents were experimented with including Agar, pectin, carboxymethylcellulose, gelatin, alginic acid, xanthan gum , guar gum ...I) Introduction and Description of Scientific Goals 1 II) Material and Powder Synthesis 1 A) Freeze Dried Fabrication of Powders 1 B) Utilization of...composites. II). Material and Powder Synthesis The availability of a reliable technique for producing large quantities of phase pure, submicron powders

  12. Composite resin reinforced with pre-tensioned fibers: a three-dimensional finite element study on stress distribution.

    Science.gov (United States)

    Jie, Lin; Shinya, Akikazu; Lassila, Lippo V J; Vallittu, Pekka K

    2013-01-01

    Pre-tensioned construction material is utilized in engineering applications of high strength demands. The purpose of this study was to evaluate the effect of the pre-tensioning fibers of fiber-reinforced composite (FRC) using three-dimensional finite element (FE) analysis. The 3D FE models of particulate composite resin (CR), FRC and composite resin reinforced with pre-tensioned fibers (PRE-T-FRC) were constructed. The uniaxial three-point bending test was simulated using FE analysis to calculate the principal stress distribution. In the FRC and PRE-T-FRC, stresses were higher than CR, and they were located in the fiber. However, the maximum principal stress value at the composite of PRE-T-FRC was lower than the FRC and CR. Composite resin reinforced with pre-tensioned fibers was advantageous for stress distribution and lowering the stress at the composite itself. Experimental studies on physical properties of pre-tensioned FRC are encouraged to be conducted.

  13. Theoretical studies of field-reversed configurations (FRCs) and experimental study of the FRC during translation

    Energy Technology Data Exchange (ETDEWEB)

    Siemon, R.E.; Armstrong, W.T.; Chrien, R.E.; Klingner, P.L.; Linford, R.K.; McKenna, K.F.; Rej, D.J.; Schwarzmeier, J.L.; Sgro, A.; Sherwood, E.G.

    1984-08-01

    Theoretical studies of FRC stability and tranport are summarized. Finite Larmor radius theories are shown to be unreliable for explaining the experimentally observed stability to tilting. Control of the n=2 rotational instability has been demonstrated in 2-dimensional hybrid-code simulations, and the stability appears to be described within MHD if the nearly square equilibria that result from quadrupole fields are taken into account. Simulations of the lower-hybrid-drift instability in parameter regimes relevant to experiments show good agreement with a nonlocal theory of the instability. A 1.5-dimensional transport code shows agreement with the energy confinement time but disagreement with the flux loss time observed in FRX-C. The process of FRC translation in which the plasma is formed, translated into a dc solenoid, and trapped by magnetic mirrors has been studied in the FRX-C/T experiment.

  14. Theoretical studies of field-reversed configurations (FRCs) and experimental study of the FRC during translation

    International Nuclear Information System (INIS)

    Siemon, R.E.; Armstrong, W.T.; Chrien, R.E.

    1984-08-01

    Theoretical studies of FRC stability and tranport are summarized. Finite Larmor radius theories are shown to be unreliable for explaining the experimentally observed stability to tilting. Control of the n=2 rotational instability has been demonstrated in 2-dimensional hybrid-code simulations, and the stability appears to be described within MHD if the nearly square equilibria that result from quadrupole fields are taken into account. Simulations of the lower-hybrid-drift instability in parameter regimes relevant to experiments show good agreement with a nonlocal theory of the instability. A 1.5-dimensional transport code shows agreement with the energy confinement time but disagreement with the flux loss time observed in FRX-C. The process of FRC translation in which the plasma is formed, translated into a dc solenoid, and trapped by magnetic mirrors has been studied in the FRX-C/T experiment

  15. High Fidelity Modeling of Field-Reversed Configuration (FRC) Thrusters (Briefing Charts)

    Science.gov (United States)

    2017-05-24

    THRUSTERS (Briefing Charts) Robert Martin , Eder Sousa, Jonathan Tran Air Force Research Laboratory (AFMC) AFRL/RQRS 1 Ara Drive Edwards AFB, CA 93524... Martin N/A HIGH FIDELITY MODELING OF FIELD-REVERSED CONFIGURATION (FRC) THRUSTERS Robert Martin1, Eder Sousa2, Jonathan Tran2 1AIR FORCE RESEARCH...Distribution is unlimited. PA Clearance No. 17314 MARTIN , SOUSA, TRAN (AFRL/RQRS) DISTRIBUTION A - APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED. PA

  16. Global blending optimization of laminated composites with discrete material candidate selection and thickness variation

    DEFF Research Database (Denmark)

    Sørensen, Søren N.; Stolpe, Mathias

    2015-01-01

    rate. The capabilities of the method and the effect of active versus inactive manufacturing constraints are demonstrated on several numerical examples of limited size, involving at most 320 binary variables. Most examples are solved to guaranteed global optimality and may constitute benchmark examples...... but is, however, convex in the original mixed binary nested form. Convexity is the foremost important property of optimization problems, and the proposed method can guarantee the global or near-global optimal solution; unlike most topology optimization methods. The material selection is limited...... for popular topology optimization methods and heuristics based on solving sequences of non-convex problems. The results will among others demonstrate that the difficulty of the posed problem is highly dependent upon the composition of the constitutive properties of the material candidates....

  17. Novel sensing approach for LPG leakage detection: Part II: Effects of particle size, composition and coating layer thickness

    KAUST Repository

    Mukhopadhyay, Subhas

    2015-10-30

    Prominent research has been going on to develop a low-cost, efficient gas sensing system. The paper presents a continuation of our earlier research work done to develop a new sensing approach for gas detection at ambient conditions. The work exhibits the optimization of the response time of the sensor by inhabiting characteristic changes like variation in the concentration of the dispersion medium, thickness of the coating and the size of the dispersed medium. Different concentrations of the dispersion medium in the coated suspension were tested to determine the optimal composition required to achieve the highest sensitivity of the tin oxide (SnO2) layer towards the tested gas. The control over adsorption and desorption of the gas molecules in the coated layer was achieved by investigating the particle size of the dispersed medium. The response time of the coated sensor was encouraging and owns a promising potential to the development of a more efficient gas sensing system.

  18. Effect of Firing Temperature on the Composition and Structural Parameters of Screen Printed ZrO2 Thick Film Sensors

    Directory of Open Access Journals (Sweden)

    S. J. PATIL

    2010-12-01

    Full Text Available The compositional, morphological and structural properties of ZrO2 thick films prepared by a standard screen printing method and fired between 800 oC to 1000 oC for 2 hours in an air atmosphere. The material characterization was done using X-ray energy dispersive analysis (EDX, X-ray diffraction (XRD and a scanning electron microscope (SEM. The deposited films were polycrystalline in nature having the monoclinic, tetragonal- cubic structure with a preferred orientation along the (1’11 plane. The result shows that the mass % of Zr was found to be 79.10, 82.14 and 82.04 % for firing temperatures of 800, 900 and 1000 0C respectively may be due to the release of excess oxygen. The effect of the firing temperature on structural parameters such as the crystallite size, percentage of phases, texture coefficient, RMSmicrostrain, dislocation density and stacking fault probability have been studied. The results indicate that grain growth can be increased by increasing the firing temperature which is responsible for decreasing the RMSmicrostrain and dislocation density in ZrO2 thick films. The stacking fault probability remains constant for all firing temperatures. The crystallite size changes from 25.71 nm to 30.80 nm with respect to the increase in the firing temperature.

  19. Fiber-reinforced Composite for Chairside Replacement of Anterior ...

    African Journals Online (AJOL)

    Fiber-reinforced Composite for Chairside Replacement of Anterior Teeth: A Case Report. ... investigation will be required to provide additional information on the survival of directly-bonded anterior fixed prosthesis made with FRC systems.

  20. Formation of Field Reversed Configuration (FRC on the Yingguang-I device

    Directory of Open Access Journals (Sweden)

    Qizhi Sun

    2017-09-01

    Full Text Available As a hybrid approach to realizing fusion energy, Magnetized Target Fusion (MTF based on the Field Reversed Configuration (FRC, which has the plasma density and confinement time in the range between magnetic and inertial confinement fusion, has been recently widely pursued around the world. To investigate the formation and confinement of the FRC plasma injector for MTF, the Yingguang-I, which is an FRC test device and contains a multi-bank program-discharged pulsed power sub-system, was constructed at the Institute of Fluid Physics (IFP, China. This paper presents the pulsed power components and their parameters of the device in detail, then gives a brief description of progress in experiments of FRC formation. Experimental results of the pulsed power sub-system show that the peak current/magnetic field of 110 kA/0.3 T, 10 kA/1.2 T and 1.7 MA/3.4 T were achieved in the bias, mirror and θ-pinch circuits with quarter cycle of 80 μs, 700 μs and 3.8 μs respectively. The induced electric field in the neutral gas was greater than 0.25 kV/cm when the ionization bank was charged to 70 kV. With H2 gas of 8 Pa, the plasma target of density 1016 cm−3, separatrix radius 4 cm, half-length 17 cm, equilibrium temperature 200 eV and lifetime 3 μs (approximately the half pulse width of the reversed field have been obtained through the θ-pinch method when the bias, mirror, ionization and θ-pinch banks were charged to 5 kV, 5 kV, 55 kV and ±45 kV respectively. The images from the high-speed end-on framing camera demonstrate the formation processes of FRC and some features agree well with the results with the two-dimension magneto hydrodynamics code (2D-MHD.

  1. Calculation of Al2O3 contents in Al2O3-PTFE composite thick films fabricated by using the aerosol deposition

    International Nuclear Information System (INIS)

    Kim, Hyung-Jun; Kim, Yoon-Hyun; Nam, Song-Min; Yoon, Young-Joon; Kim, Jong-Hee

    2010-01-01

    Low-temperature fabrication of Al 2 O 3 -PTFE (poly tetra fluoro ethylene) composite thick films for flexible integrated substrates was attempted by using the aerosol deposition method. For optimization of composite thick films, a novel calculation method for the ceramic contents in the composites was attempted. Generally, a thermogravimetry (TG) analysis is used to calculate the ceramic contents in the ceramic-polymer composites. However, the TG analysis requires a long measurement time in each analysis, so we studied a novel calculation method that used a simple dielectric measurement. We used Hashin-Shtrikman bounds to obtain numerical results for the relationship between the dielectric constant of the composites and the contents of Al 2 O 3 . A 3-D electrostatic simulation model similar to the deposited Al 2 O 3 -PTFE composite thick films was prepared, and the simulation result was around the lower bound of the Hashin-Shtrikman bounds. As a result, we could calculate the Al 2 O 3 contents in the composites with a low error of below 5 vol.% from convenient dielectric measurements, and the Al 2 O 3 contents ranged from 51 vol.% to 54 vol.%.

  2. Comparison of silorane and methacrylate-based composites on the polymerization heat generated with different light-curing units and dentin thicknesses.

    Science.gov (United States)

    Guiraldo, Ricardo Danil; Consani, Simonides; Consani, Rafael Leonardo Xediek; Berger, Sandrine Bittencourt; Correr, Américo Bortolazzo; Sinhoreti, Mário Alexandre Coelho; Correr-Sobrinho, Lourenço

    2013-01-01

    This study evaluated the temperature variation in the pulp chamber during photoactivation of two restorative composite resins (Filtek P90 silorane-based composite and Heliomolar methacrylate-based composite) with either a quartz-tungsten-halogen (QTH) or light-emitting diodes (LED) light-curing unit (LCU) and using dentin thicknesses (0.5 and 1.0 mm). Standardized cavities (2x2x2 mm) were prepared in 80 bovine incisors, which were randomly assigned to 8 groups according to the photoactivation method and dentin thickness. Filtek P90 and Heliomolar (both in shade A3) were used with their respective adhesive systems (P90 self-etch primer / P90 adhesive bond and Excite adhesive). All experiments were carried out in a controlled environment (37°C). The temperature variations (°C) were recorded using a digital thermometer attached to a K-type thermocouple. The results were analyzed statistically by ANOVA and Tukey's test (α=0.05). For composite/dentin thickness interaction, temperature increase was significantly higher in 0.5 mm dentin thickness (40.07°C) compared with 1.0 mm dentin thickness (39.61°C) for Filtek P90. For composite/LCU interaction, the temperature increase was significantly higher for Filtek P90 (39.21°C - QTH and 40.47°C - LED) compared with Heliomolar (38.40°C - QTH and 39.30°C - LED). The silorane-based composite promoted higher temperature increase in the pulp chamber than the methacrylate-based composite.

  3. Model, prediction, and experimental verification of composition and thickness in continuous spread thin film combinatorial libraries grown by pulsed laser deposition

    International Nuclear Information System (INIS)

    Bassim, N. D.; Schenck, P. K.; Otani, M.; Oguchi, H.

    2007-01-01

    Pulsed laser deposition was used to grow continuous spread thin film libraries of continuously varying composition as a function of position on a substrate. The thickness of each component that contributes to a library can be empirically modeled to a bimodal cosine power distribution. We deposited ternary continuous spread thin film libraries from Al 2 O 3 , HfO 2 , and Y 2 O 3 targets, at two different background pressures of O 2 : 1.3 and 13.3 Pa. Prior to library deposition, we deposited single component calibration films at both pressures in order to measure and fit the thickness distribution. Following the deposition and fitting of the single component films, we predict both the compositional coverage and the thickness of the libraries. Then, we map the thickness of the continuous spread libraries using spectroscopic reflectometry and measure the composition of the libraries as a function of position using mapping wavelength-dispersive spectrometry (WDS). We then compare the compositional coverage of the libraries and observe that compositional coverage is enhanced in the case of 13.3 Pa library. Our models demonstrate linear correlation coefficients of 0.98 for 1.3 Pa and 0.98 for 13.3 Pa with the WDS

  4. Study of field induced hot-electron emission using the composite microemitters with varying dielectric layer thickness

    International Nuclear Information System (INIS)

    Mousa, M.S.

    1987-07-01

    The analysis of the measurements obtained from the of field emission of electrons from composite metal-insulator (M-I) micropoint cathodes, using the combination of a high resolution electron spectrometer and a field emission microscope, has been presented. Results obtained describe the reversible current-voltage characteristic, emission images and electron energy distribution measurements of both thin and the optimum thick coatings. The observed effects, e.g. the threshold switch-on phenomena and the field-dependence of the F.W.H.M. and energy shift of the electron spectra have been identified in terms of a field-induced hot-electron emission (FIHEE) mechanism resulting from field penetration in the insulating film where conducting channels are formed. The theoretical implications accounts for the channels field intensification mechanism and the conduction properties with applied field, and the F.W.H.M. dependence on electron temperature. The control of the emission process at low fields by the M-I contact junction and at high fields by the bulk properties of the insulator have also been accounted for. These experimental and theoretical findings have been shown to be consistent with recently published data on M-I microstructures on broad-area (BA) high-voltage electrodes. (author). 18 refs, 6 figs

  5. Free and Forced Vibration of the Moderately Thick Laminated Composite Rectangular Plate on Various Elastic Winkler and Pasternak Foundations

    Directory of Open Access Journals (Sweden)

    Dongyan Shi

    2017-01-01

    Full Text Available An improved Fourier series method (IFSM is applied to study the free and forced vibration characteristics of the moderately thick laminated composite rectangular plates on the elastic Winkler or Pasternak foundations which have elastic uniform supports and multipoints supports. The formulation is based on the first-order shear deformation theory (FSDT and combined with artificial virtual spring technology and the plate-foundation interaction by establishing the two-parameter foundation model. Under the framework of this paper, the displacement and rotation functions are expressed as a double Fourier cosine series and two supplementary functions which have no relations to boundary conditions. The Rayleigh-Ritz technique is applied to solve all the series expansion coefficients. The accuracy of the results obtained by the present method is validated by being compared with the results of literatures and Finite Element Method (FEM. In this paper, some results are obtained by analyzing the varying parameters, such as different boundary conditions, the number of layers and points, the spring stiffness parameters, and foundation parameters, which can provide a benchmark for the future research.

  6. Control of a metalorganic chemical vapor deposition process for improved composition and thickness precision in compound semiconductors

    Science.gov (United States)

    Gaffney, Monique Suzanne

    1998-11-01

    Metalorganic chemical vapor deposition (MOCVD) is a process used to manufacture electronic and optoelectronic devices that has traditionally lacked real-time growth monitoring and control. Controlling the growth rate and composition using the existing sensors, as well as advanced monitoring systems developed in-house, is shown to improve device quality. Specific MOCVD growth objectives are transformed into controller performance goals. Group III bubbler concentration variations, which perturb both growth rate and composition precision, are identified to be the primary disturbances. First a feed forward control system was investigated, which used an ultrasonic concentration monitor, located upstream in the process. This control strategy resulted in improved regulation of the gallium delivery rate by cancelling the sensed gallium bubbler concentration disturbances via the injection mass flow controller. The controller performance is investigated by growing GaInAs/InP superlattices. Results of growths performed under normal operating conditions and also under large perturbations include X-ray diffraction from the samples as well as real-time sensor signal data. High quality superlattices that display up to eight orders of satellite peaks are obtained under the feed forward compensation scheme, demonstrating improved layer-to-layer reproducibility of thickness and composition. The success of the feed forward control demonstration led to the development of a more complex downstream feedback control system. An ultraviolet absorption monitor was fabricated and retrofitted as a feedback control signal. A control-oriented model of the downstream process was developed for the feedback controller synthesis. Although challenged with both the photolysis and multi-gas detection issues common to UV absorption monitors, closed loop control with the UV sensor was performed and proved to be an effective method of disturbance rejection. An InP/GaInAs test structure was grown under

  7. Effect of thickness and composition on the structure and ordering in La-doped intergranular films between Si{sub 3}N{sub 4} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Yun [Interfacial Molecular Science Laboratory, Department of Materials Science and Engineering, Rutgers University, 607 Taylor Rd., Piscataway, NJ 08855 (United States); Garofalini, Stephen H., E-mail: shg@rutgers.edu [Interfacial Molecular Science Laboratory, Department of Materials Science and Engineering, Rutgers University, 607 Taylor Rd., Piscataway, NJ 08855 (United States)

    2011-08-15

    Molecular dynamics simulations were used to determine the effect of the composition and thickness on the atomistic structure of La-Si-O-N intergranular films (IGFs) between prism and misaligned high-index silicon nitride crystals. Results showed that ordered La adsorption onto the prism-terminated surface is not affected by the orientation of the opposing crystal, although the extent of the ordering away from the interface is affected by IGF thickness. La adsorption at ordered sites 1 and 2 on the prism surface occurred for almost all of the compositions in both 1.8 and 0.6 nm thick IGFs and at sites farther from the prism interface in the thicker IGF, similar to adsorption in triple points. La adsorption on the prism surface occurred at sites precisely the same as seen in high-angle annular dark field scanning transmission electron microscopy studies. Saturation of available sites is affected by the thickness of the IGF, which governs the number of La ions (and N ions) in the IGF, with lower site filling in the thinner IGF. There are clear energy differences for La in the interior of the IGF vs. the interface based on composition and IGF thickness, with the thicker IGF showing greater variation in driving forces for segregation or La incorporation into the IGF. Fracture is affected by both composition and thickness and occurs in the glassy IGF and not in the ordered interfacial regions, consistent with experimentally observed intergranular fracture for La-doped silicon nitride. Segregation of La to the interface affects N distribution within the interior of the IGF, which affects strength.

  8. Effect of reinforcement with resin composite on fracture strength of structurally compromised roots.

    Science.gov (United States)

    Fukui, Yuji; Komada, Wataru; Yoshida, Keiichi; Otake, Shiho; Okada, Daizo; Miura, Hiroyuki

    2009-09-01

    This study was aimed at evaluating the fracture resistance of structurally compromised roots restored with four different post and core systems. Thirty-two bovine roots were uniformly shaped to simulate human mandibular premolar roots. The roots were divided into four groups based on the type of restoration: cemented cast post and core (Group MC), resin composite build-up (Group CR), resin composite and prefabricated glass fiber post build-up (Group FRC), and thick-layer dual-cured resin composite-reinforced small-diameter tapered cast post and core (Group CRM). After a static loading test, the failure mode and fracture resistance were recorded. Group CRM (719.38+/-196.73 N) exhibited a significantly high fracture resistance compared with the other groups (Group MC: 429.56+/-82.43 N; Group CR: 349.56+/-66.21 N; Group FRC: 398.94+/-112.71 N; pCRM exhibited better mechanical properties for structurally compromised roots with no ferrules, although all types of restorations showed non-restorable fracture modes.

  9. UEDGE Simulations for Power and Particle Flow Analysis of FRC Rocket

    Science.gov (United States)

    Zheng, Fred; Evans, Eugene S.; McGreivy, Nick; Kaptanoglu, Alan; Izacard, Olivier; Cohen, Samuel A.

    2017-10-01

    The field-reversed configuration (FRC) is under consideration for use in a direct fusion drive (DFD) rocket propulsion system for future space missions. To achieve a rocket configuration, the FRC is embedded within an asymmetric magnetic mirror, in which one end is closed and contains a gas box, and the other end is open and incorporates a magnetic nozzle. Neutral deuterium is injected into the gas box, and flows through the scrape-off layer (SOL) around the core plasma and out the magnetic nozzle, both cooling the core and serving as propellant. Previous studies have examined a range of operating conditions for the SOL of a DFD using UEDGE, a 2D fluid code; discrepancies on the order of 5% were found during the analysis of overall power balance. This work extends the analysis of the previously-studied SOL geometry by updating boundary conditions and conducting a detailed study of power and particle flows within the simulation with the goals of modeling electrical power generation instead of thrust and achieving higher specific impulse. This work was supported, in part, by DOE Contract Number DE-AC02-09CH11466 and Princeton Environmental Institute.

  10. 1.4D quasistatic profile model of transport in a field-reversed configuration (FRC)

    International Nuclear Information System (INIS)

    Steinhauer, L.C.

    1990-01-01

    Global confinement models are useful for determining how a given transport mechanism (dependent on local parameters) translates into global confinement times. Such models are also useful for inferring the overall magnitudes of transport rates, and limited information about their spatial profiles. They are especially important in a field reversed configuration (FRC) where the equilibrium and transport rates are so intimately coupled, and where the flux loss time is such an important factor. An earlier global FRC confinement model, sometimes called QUASI, was based on the assumption of a quasi-steady equilibrium. The equilibrium was assumed to have square-ends with some features of 2D equilibria: (1) equal pressure on inner and outer branches of the flux lines; and (2) average-beta relation. Models of this type have been called 1-1/4D transport models. The same general approach has now been applied in a straightforward way to an equilibrium with realistic axial structure. This might be called a 1.4D quasisteady transport model. The assumed axial structure can be that of an analytic equilibrium, or a more complicated computed equilibrium as desired. The example used here is an elongated Hill's vortex equilibrium. As will be shown later, the equilibrium is reflected by two integral quantities that appear in the quasistatic diffusion equation

  11. Investigation of Technetium Redox Cycling in FRC Background Sediments using EXAFS and Gamma Camera Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lloyd, J.R.; McBeth, J.M.; Lear, G.; Morris, K.; Burke, I.T.; Livens, F.R.; Ellis, B.; Lawson, R.

    2006-04-05

    Technetium-99 is a priority pollutant at numerous DOE sites, due to its long half-life (2.1 x 105 years), high mobility as Tc(VII) in oxic waters, and bioavailability as a sulfate analogue. {sup 99}Tc is far less mobile under anaerobic conditions, forming insoluble Tc(IV) precipitates. As anaerobic microorganisms can reduce soluble Tc(VII) to insoluble Tc(IV), microbial metabolism may have the potential to treat sediments and waters contaminated with Tc. Baseline studies of fundamental mechanisms of Tc(VII) bioreduction and precipitation (reviewed by Lloyd et al., 2005, in press) have generally used pure cultures of metal-reducing bacteria, in order to develop conceptual models for the biogeochemical cycling of {sup 99}Tc. There is, however, comparatively little known about interactions of metal-reducing bacteria with environmentally relevant trace concentrations of {sup 99}Tc, against a more complex biogeochemical background provided by mixed microbial communities in aquifer sediments. The objective of this project is to probe the site specific biogeochemical conditions that control the mobility of {sup 99}Tc at the US DOE Field Research Center Site (FRC; Oak Ridge, Tennessee). This information is required for the rational design of in situ bioremediation strategies for technetium-contaminated subsurface environments. We are using a combination of geochemical, mineralogical, microbiological and spectroscopic techniques to determine the solubility and phase associations of {sup 99}Tc in FRC sediments, and characterize the underpinning biogeochemical controls.

  12. Compositional variation within thick (>10 m) flow units of Mauna Kea Volcano cored by the Hawaii Scientific Drilling Project

    Science.gov (United States)

    Huang, Shichun; Vollinger, Michael J.; Frey, Frederick A.; Rhodes, J. Michael; Zhang, Qun

    2016-07-01

    Geochemical analyses of stratigraphic sequences of lava flows are necessary to understand how a volcano works. Typically one sample from each lava flow is collected and studied with the assumption that this sample is representative of the flow composition. This assumption may not be valid. The thickness of flows ranges from 100 m. Geochemical heterogeneity in thin flows may be created by interaction with the surficial environment whereas magmatic processes occurring during emplacement may create geochemical heterogeneities in thick flows. The Hawaii Scientific Drilling Project (HSDP) cored ∼3.3 km of basalt erupted at Mauna Kea Volcano. In order to determine geochemical heterogeneities in a flow, multiple samples from four thick (9.3-98.4 m) HSDP flow units were analyzed for major and trace elements. We found that major element abundances in three submarine flow units are controlled by the varying proportion of olivine, the primary phenocryst phase in these samples. Post-magmatic alteration of a subaerial flow led to loss of SiO2, CaO, Na2O, K2O and P2O5, and as a consequence, contents of immobile elements, such as Fe2O3 and Al2O3, increase. The mobility of SiO2 is important because Mauma Kea shield lavas divide into two groups that differ in SiO2 content. Post-magmatic mobility of SiO2 adds complexity to determining if these groups reflect differences in source or process. The most mobile elements during post-magmatic subaerial and submarine alteration are K and Rb, and Ba, Sr and U were also mobile, but their abundances are not highly correlated with K and Rb. The Ba/Th ratio has been used to document an important role for a plagioclase-rich source component for basalt from the Galapagos, Iceland and Hawaii. Although Ba/Th is anomalously high in Hawaiian basalt, variation in Ba abundance within a single flow shows that it is not a reliable indicator of a deep source component. In contrast, ratios involving elements that are typically immobile, such as La/Nb, La

  13. Fibras reforçadas por resina (FRC em Ortodontia. Versatilidade clínica: parte 2 Fiber reinforced composite (FRC in Orthodontic. Clinical versatility: part II

    Directory of Open Access Journals (Sweden)

    Daniel Ianni Filho

    2005-06-01

    Full Text Available As fibras de vidro e de polietileno podem ser utilizadas na prática ortodôntica em diversas situações clínicas, nos casos com ou sem extrações dentárias. Este artigo tem como objetivo mostrar algumas das aplicações clínicas nas quais as fibras contribuíram de forma significativa para a realização dos tratamentos ortodônticos, simplificando-os e aumentando a eficiência clínica. As fibras foram utilizadas principalmente em segmentos de ancoragem e na substituição da banda pela colagem da associação fibra/tubo nos molares.Glass and polyethylene fibers can be used in orthodontic practice on several clinical(s situations, in cases with or without teeth extraction. The objective of this article is to show some of the clinical applications in which the fibers contributed in a positive way to improve the performance of orthodontic treatments, simplifying and raiseing the clinical efficiency. These fibers were mainly used on anchorage segments, and as a substitute for the band by bonding the fiber/tube association in molars.

  14. Applicability of X-ray fluorescence spectroscopy as method to determine thickness and composition of stacks of metal thin films: A comparison with imaging and profilometry

    International Nuclear Information System (INIS)

    Vrielink, J.A.M.; Tiggelaar, R.M.; Gardeniers, J.G.E.; Lefferts, L.

    2012-01-01

    In this work the applicability of X-ray fluorescence spectroscopy (XRF) for fast, accurate and non-destructive determination of the thickness of a variety of single-layer and multi-layer metal thin films deposited on glass and silicon is investigated. Data obtained with XRF is compared with information from profilometry and images from scanning electron microscopy (SEM). Whereas thickness determinations based on profilometry and cross-sectional SEM-imaging have restrictions with respect to thickness of metal stacks or hardness of the metals, XRF has no such limitations. Moreover, XRF can discriminate between sublayers in a multi-layer film, and can also be utilized for compositional analysis and density estimations. Good agreement between thickness data obtained with XRF, profilometry and SEM-images is found, under the justifiable assumption that the density of sputter-deposited and evaporated thin films is ca. 5% below that of bulk metals. Similar XRF-results are found for non-patterned areas (64 mm 2 metal) as well as lithographically patterned areas containing a series of small metal lines (total metal surface ca. 8 mm 2 ). As a consequence, it is concluded that XRF is a versatile technique for analysis, verification, control or evaluation of the thickness, density or (elemental) composition of thin metal film line-patterns, during their fabrication as well as prior or post to applications.

  15. Influence of Filler Alloy Composition and Process Parameters on the Intermetallic Layer Thickness in Single-Sided Cold Metal Transfer Welding of Aluminum-Steel Blanks

    Science.gov (United States)

    Silvayeh, Zahra; Vallant, Rudolf; Sommitsch, Christof; Götzinger, Bruno; Karner, Werner; Hartmann, Matthias

    2017-11-01

    Hybrid components made of aluminum alloys and high-strength steels are typically used in automotive lightweight applications. Dissimilar joining of these materials is quite challenging; however, it is mandatory in order to produce multimaterial car body structures. Since especially welding of tailored blanks is of utmost interest, single-sided Cold Metal Transfer butt welding of thin sheets of aluminum alloy EN AW 6014 T4 and galvanized dual-phase steel HCT 450 X + ZE 75/75 was experimentally investigated in this study. The influence of different filler alloy compositions and welding process parameters on the thickness of the intermetallic layer, which forms between the weld seam and the steel sheet, was studied. The microstructures of the weld seam and of the intermetallic layer were characterized using conventional optical light microscopy and scanning electron microscopy. The results reveal that increasing the heat input and decreasing the cooling intensity tend to increase the layer thickness. The silicon content of the filler alloy has the strongest influence on the thickness of the intermetallic layer, whereas the magnesium and scandium contents of the filler alloy influence the cracking tendency. The layer thickness is not uniform and shows spatial variations along the bonding interface. The thinnest intermetallic layer (mean thickness < 4 µm) is obtained using the silicon-rich filler Al-3Si-1Mn, but the layer is more than twice as thick when different low-silicon fillers are used.

  16. The effect of layer thickness and composition on the kinetics of solid state reactions in the niobium-selenium system studied using superlattice reactants

    International Nuclear Information System (INIS)

    Fukuto, M.; Kevan, S.D.

    1997-01-01

    The ability to form an amorphous reaction intermediate by the low temperature interdiffusion of a modulated elemental reactant is shown to be a function of the overall composition as well as elemental layer thicknesses in the niobium-selenium system. For niobium-rich reactants, an amorphous reaction intermediate was observed to form upon low temperature annealing of reactants with modulation thicknesses less than 60 A. Further annealing of the amorphous intermediates led to the crystallization of Nb 2 Se, Nb 5 Se 4 or Nb 3 Se 4 depending upon the overall composition of the amorphous intermediate. Modulated elemental reactants with overall compositions containing more than two-thirds selenium were found to heterogeneously nucleate NbSe 2 at the reacting interfaces. The formation of the thermodynamically expected compounds Nb 2 Se 3 , NbSe 3 , and Nb 2 Se 9 at their respective compositions required extended high temperature annealing to react the dichalcogenide with the remaining elemental reactants. A striking difference between the evolution of the low angle diffraction patterns in these two composition regimes suggests the differences in the reaction kinetics result from a composition dependence of the diffusion coefficients. (orig.)

  17. Effect of reinforcement amount, mold temperature, superheat, and mold thickness on fluidity of in-situ Al-Mg2Si composites

    Directory of Open Access Journals (Sweden)

    Reza Vatankhah Barenji

    2018-01-01

    Full Text Available In the present study, the effects of mold temperature, superheat, mold thickness, and Mg2Si amount on the fluidity of the Al-Mg2Si as-cast in-situ composites were investigated using the mathematical models. Composites with different amounts of Mg2Si were fabricated, and the fluidity and microstructure of each were then analyzed. For this purpose, the experiments were designed using a central composite rotatable design, and the relationship between parameters and fluidity were developed using the response surface method. In addition, optical and scanning electron microscopes were used for microstructural observation. The ANOVA shows that the mathematical models can predict the fluidity accurately. The results show that by increasing the mold temperature from 25 °C to 200 °C, superheat from 50 °C to 250 °C, and thickness from 3 mm to 12 mm, the fluidity of the composites decreases, where the mold thickness is more effective than other factors. In addition, the higher amounts of Mg2Si in the range from 15wt.% to 25wt.% lead to the lower fluidity of the composites. For example, when the mold temperature, superheat, and thickness are respectively 100 °C, 150 °C, and 7 mm, the fluidity length is changed in the range of 11.9 cm to 15.3 cm. By increasing the amount of Mg2Si, the morphology of the primary Mg2Si becomes irregular and the size of primary Mg2Si is increased. Moreover, the change of solidification mode from skin to pasty mode is the most noticeable microstructural effect on the fluidity.

  18. Biogeochemistry of Fe and Tc Reduction and Oxidation in FRC Sediment

    International Nuclear Information System (INIS)

    John M, Zachara; James K, Fredrickson; Ravi K, Kukkadapu; Steven C, Smith; David W, Kennedy

    2004-01-01

    The objectives are: (1) To rigorously characterize the distribution of Fe(II) and Fe(III) in FRC sediment. (2) To identify changes to Fe(II)/Fe(III) distribution and concentration resulting from DIRB activity. (3) To determine the dependence of Tc(VII) reduction rate on biogenic Fe(II) and it's forms. (4) To establish tendency of Tc(IV) and biogenic Fe(II) to oxidize and their effects on Tc immobilization. The mineralogic and chemical properties of the pristine, bioreduced, and chemically extracted FRC sediments were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), X-ray microscopy (XRM, at the PNC-CAT beamline at APS), Moessbauer spectroscopy, and scanning and transmission electron microscopy with lattice fringe imaging. Chemical extraction included dithionite-citrate-bicarbonate (DCB), acid ammonium oxalate (AAO), and hydroxylamine hydrochloride (HAH). The FRC sediment was incubated under anoxic conditions with the facultative dissimilatory metal-reducing bacterium Shewanella putrefaciens, strain CN32 in defined aqueous solutions/media with bicarbonate and PIPES buffers for time periods exceeding 75 d. Lactate was used as the electron donor. Aqueous and sorbed Fe(II) (ferrozine assay and 0.5 N HCl extraction) and Mn(II) (ICP-MS and 10 mM CuSO 4 extraction), and pH were monitored to define the reduction progress and extent. The bioreduced materials were characterized using the abovementioned techniques. Bioreduced (pasteurized) sediment or chemically extracted/reduced sediment spiked with Fe(II) was washed with a PIPES buffer/electrolyte solution, and spiked with NaTc(VII)O 4 to yield a concentration of 20 (micro)M. The Tc(VII)-spiked samples were agitated and equilibrated at 25 C and sampled over time to assess the Tc(VII) reduction rate. Selected sediment samples containing 20 (micro)M of reduced Tc [Tc(IV)] were subjected to oxidation by: (1) successive headspace replacements of air, and (2) open system equilibration with air. Removed aqueous

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

    Science.gov (United States)

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

    2018-05-01

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

  20. Influences of carbon content and coating carbon thickness on properties of amorphous CoSnO3@C composites as anode materials for lithium-ion batteries

    Science.gov (United States)

    Fan, Fuqiang; Fang, Guoqing; Zhang, Ruixue; Xu, Yanhui; Zheng, Junwei; Li, Decheng

    2014-08-01

    A series of core-shell carbon coated amorphous CoSnO3 (CoSnO3@C) with different carbon content are synthesized. Effects of carbon content and coating carbon thickness on the physical and electrochemical performances of the samples were studied in detail. The samples were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), galvanostatic charge-discharge and AC impedance spectroscopy, respectively. The results indicate that controlling the concentration of aqueous glucose solution influences the generation of in-situ carbon layer thickness. The optimal concentration of aqueous glucose solution, carbon content and carbon layer thickness are suggested as 0.25 M, 35.1% and 20 nm, respectively. CoSnO3@C composite prepared under the optimal conditions exhibits excellent cycling performance, whose reversible capacity could reach 491 mA h g-1 after 100 cycles.

  1. Multiple solutions of a free-boundary FRC equilibrium problem in a metal cylinder

    International Nuclear Information System (INIS)

    Spencer, R.L.; Hewett, D.W.

    1981-01-01

    A new approach to the computation of FRC equilibria that avoids previously encountered difficulties is presented. For arbitrary pressure profiles it is computationally expensive, but for one special pressure profile the problem is simple enough to require only minutes of Cray time; it is this problem that we have solved. We solve the Grad-Shafranov equation, Δ/sup */psi = r 2 p'(psi), in an infinitely long flux conserving cylinder of radius a with the boundary conditions that psi(a,z) = -psi/sub w/ and that delta psi/delta z = 0 as [z] approaches infinity. The pressure profile is p'(psi) = cH(psi) where c is a constant and where H(x) is the Heaviside function. We have found four solutions to this problem: There is a purely vacuum state, two z-independent plasma solutions, and an r-z-dependent plasma state

  2. Absolute calibration of neutron detectors on the C-2U advanced beam-driven FRC

    Energy Technology Data Exchange (ETDEWEB)

    Magee, R. M., E-mail: rmagee@trialphaenergy.com; Clary, R.; Korepanov, S.; Jauregui, F.; Allfrey, I.; Garate, E.; Valentine, T.; Smirnov, A. [Tri Alpha Energy, Inc., Rancho Santa Margarita, California 92688 (United States)

    2016-11-15

    In the C-2U fusion energy experiment, high power neutral beam injection creates a large fast ion population that sustains a field-reversed configuration (FRC) plasma. The diagnosis of the fast ion pressure in these high-performance plasmas is therefore critical, and the measurement of the flux of neutrons from the deuterium-deuterium (D-D) fusion reaction is well suited to the task. Here we describe the absolute, in situ calibration of scintillation neutron detectors via two independent methods: firing deuterium beams into a high density gas target and calibration with a 2 × 10{sup 7} n/s AmBe source. The practical issues of each method are discussed and the resulting calibration factors are shown to be in good agreement. Finally, the calibration factor is applied to C-2U experimental data where the measured neutron rate is found to exceed the classical expectation.

  3. Some Aspects of Formation of Cracks in FRC with Main Reinforcement

    DEFF Research Database (Denmark)

    Brincker, Rune; Simonsen, J.; Hansen, W.

    1997-01-01

    In this paper the response of fibre reinforced concrete (FRC) with main reinforcement in pure tension is considered. Test results are presented showing three distinct regimes: a regime og linear elasticity, a regime of yielding at approximately constant stress, and finally, a regime of strain...... hardening. a simple model is presented which takes into account the debonding between the reinforcement and the fiber reinforced matrix as well as the crack opening relation of the fiber reinforced matrix. The fracture process is described from the un-cracked state and formation of the first crack till......, and a more ductile contribution from the fiber bridging, a plastic regime will be present in the tensile response. The case of a parabolic crack opening relation defines a brittleness number that describes the transition from formation of unstable discrete cracks to smaller cracks controlled by the softening...

  4. FRC formation studies in a field reversed theta pinch with a variable length coil

    International Nuclear Information System (INIS)

    Maqueda, R.; Sobehart, J.; Rodrigo, A.B.

    1987-01-01

    The formation phase of field reversed configurations (FRC) produced using a theta pinch has received considerable attention lately in connection with the possibility of developing formation methods in time scales longer than the Alven radial time, which would permit the use of low-voltage technology and represent an important engineering simplification in the trend towards larger scale machines sup (1)). The mechanisms leading to the loss of trapped reversed flux during the preheating 2 ) and formation sup (3,4)) stages, looking for maximization of this quantity in order to improve on the stability and transport properties of the configuration in its final equilibrium state are investigated. As a result, semi-emperical scaling laws have been obtained relating the reversed flux loss with experimental operating parameters during the early stages of the formation process 1 ). (author) [pt

  5. Novel sensing approach for LPG leakage detection: Part II: Effects of particle size, composition and coating layer thickness

    KAUST Repository

    Mukhopadhyay, Subhas; Nag, Anindya; Zia, Asif; Li, Xie; Kosel, Jü rgen

    2015-01-01

    exhibits the optimization of the response time of the sensor by inhabiting characteristic changes like variation in the concentration of the dispersion medium, thickness of the coating and the size of the dispersed medium. Different concentrations

  6. Representation of the thickness distribution of channels and stratigraphic events at one of the Iranian fields in the Hormuz Strait using a composite plot and RGB display technique

    International Nuclear Information System (INIS)

    Saadatinejad, M R; Javaherian, A; Hassani, H

    2011-01-01

    The Hormuz Strait is an important area which is located between the Persian Gulf, with half the oil reserves of the world, and the Oman Sea south of Iran. Many geophysical studies have been done to analyse the structure of subsurface layers in this strait and explore many new gas reservoirs as these findings help to simulate images from reservoir stratigraphy and understand the paleo-depositional environments. Spectral decomposition, which is a quick and important method in seismic interpretation, provides a strong tool to study these types of subsurface layers. In this paper, a red–green–blue (RGB) multi-colour display technique has been performed as an effective interpretation tool. This technique stacks three different frequencies with three different colours for composite display. So, these frequency components show the distribution of channel thickness as we map the variation of thickness with a colour scale that is equal to the quantitative thickness according to its relationship with frequency. In addition, seismic attributes such as coherency, peak and instantaneous frequency, which are sensitive to the edges of stratigraphic events (such as channels), are shown with a composite plot too; although the RGB technique is better than other techniques, for thickness variation a combined application is the best method of study

  7. Amino Acid Composition, Urease Activity and Trypsin Inhibitor Activity after Toasting of Soybean in Thick and Thin Layer

    OpenAIRE

    Krička, Tajana; Jurišić, Vanja; Voća, Neven; Ćurić, Duška; Brlek Savić, Tea; Matin, Ana

    2009-01-01

    The objective of this study was to determine amino acid content, urease activity and trypsin inhibitor activity in soybean grain for polygastric animals’ feed aft er toasting with the aim to introduce thick layer in toasting technology. Hence, soybean was toasted both in thick and thin layer at 130 oC during 10 minutes. In order to properly monitor the technological process of soybean thermal processing, it was necessary to study crude protein content, urease activity, trypsin inhibitor activ...

  8. Biogeochemical Controls on Technetium Mobility in Biogeochemical Controls on Technetium Mobility in FRC Sediments

    International Nuclear Information System (INIS)

    Lloyd, J.R.; McBeth, J.M.; Livens, F.R.; Bryan, N.D.; Ellis, B.; Sharma, H.; Burke, I.T.; Morris, K.

    2004-01-01

    Technetium-99 is a priority pollutant at numerous DOE sites, due to its long half-life (2.1 x 10 5 years), high mobility as Tc(VII) in oxic waters, and bioavailability as a sulfate analog. 99 Tc is far less mobile under anaerobic conditions, forming insoluble Tc(IV) precipitates. As anaerobic microorganisms can reduce soluble Tc(VII) to insoluble Tc(IV), microbial metabolism may have the potential to treat sediments and waters contaminated with Tc. Baseline studies of fundamental mechanisms of Tc(VII) bioreduction and precipitation (reviewed by Lloyd et al, 2002) have generally used pure cultures of metal-reducing bacteria, in order to develop conceptual models for the biogeochemical cycling of Tc. There is, however, comparatively little known about interactions of metal-reducing bacteria with environmentally relevant trace concentrations of Tc, against a more complex biogeochemical background provided by mixed microbial communities in the subsurface. The objective of this new NABIR project is to probe the site specific biogeochemical conditions that control the mobility of Tc at the FRC (Oak Ridge, TN). This information is required for the rational design of in situ bioremediation strategies for technetium-contaminated subsurface environments. We will use a combination of geochemical, mineralogical, microbiological and spectroscopic techniques to determine the solubility and phase associations of Tc in FRC sediments, and characterize the underpinning biogeochemical controls. A key strength of this project is that many of the techniques we are using have already been optimized by our research team, who are also studying the biogeochemical controls on Tc mobility in marine and freshwater sediments in the UK in a NERC funded companion study.

  9. Development of high-power inverter supply for current drive of FRC plasma

    International Nuclear Information System (INIS)

    Kitano, Katsuhisa; Higashikozono, Takamitsu; Okada, Shigefumi; Goto, Seiichi

    2003-01-01

    High-Power RF supply is developed for the current drive of FRC (Field Reversed Configuration) plasma. The rotating magnetic field is produced by the four antennas set in the parallel direction to the geometrical axis of the FRC and faced each other. The sinusoidal currents with shifted phases by 90 degree each other should be supplied to the antennas. The two power supplies are necessary if a pair of the antennas faced oppositely are connected. Considering the plasma parameters, the rotating field of 50-100kHz and 50G at the center axis is expected to be required. We develop the adequate RF power supply for the purpose. The power supply consists of the inverter circuit, the step-up transformer and the LC tank ciruit. For the switching device of the inverter circuit, the IGBT (Insulated Gate Bipolar Transistor) is adopted. The inverter circuit is full bridge type. To operate it at high voltages, its arm consists of the 3 IGBTs arranged series. The output of the inverter is connected to the tank circuit by way of the step-up transformer with air core. The tank circuit is the parallel circuit of the antenna and the capacitor. By the adjustment of the frequency of the inverter output to the resonance frequency of the tank circuit, the large sinusoidal waveform current is obtained. The developed power supply can produce the current of 5kA at 10kV to the dummy antenna with almost the same inductance of the antenna. (author)

  10. Influences of carbon content and coating carbon thickness on properties of amorphous CoSnO3@C composites as anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Fan, Fuqiang; Fang, Guoqing; Zhang, Ruixue; Xu, Yanhui; Zheng, Junwei; Li, Decheng

    2014-01-01

    Highlights: • The thickness of carbon coating layers can be successfully controlled through varying molar concentration of aqueous glucose solution. • Coating carbon thickness and carbon content are two important factors on the electrochemical performances of CoSnO3@C. • CoSnO 3 @C under optimized conditions exhibits the optimal balance between the volume buffering effect and reversible capacity. • As-prepared CoSnO 3 @C under optimized conditions shows excellent electrochemical performances, whose reversible capacity could reach 491 mA h g −1 after 100 cycles. - Abstract: A series of core–shell carbon coated amorphous CoSnO 3 (CoSnO 3 @C) with different carbon content are synthesized. Effects of carbon content and coating carbon thickness on the physical and electrochemical performances of the samples were studied in detail. The samples were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), galvanostatic charge–discharge and AC impedance spectroscopy, respectively. The results indicate that controlling the concentration of aqueous glucose solution influences the generation of in-situ carbon layer thickness. The optimal concentration of aqueous glucose solution, carbon content and carbon layer thickness are suggested as 0.25 M, 35.1% and 20 nm, respectively. CoSnO 3 @C composite prepared under the optimal conditions exhibits excellent cycling performance, whose reversible capacity could reach 491 mA h g −1 after 100 cycles

  11. Anterior thigh composition measured using ultrasound imaging to quantify relative thickness of muscle and non-contractile tissue: a potential biomarker for musculoskeletal health

    International Nuclear Information System (INIS)

    Agyapong-Badu, Sandra; Warner, Martin; Samuel, Dinesh; Stokes, Maria; Narici, Marco; Cooper, Cyrus

    2014-01-01

    This study aimed to use ultrasound imaging to provide objective data on the effects of ageing and gender on relative thickness of quadriceps muscle and non-contractile tissue thickness (subcutaneous fat, SF, combined with perimuscular fascia). In 136 healthy males and females (aged 18–90 years n = 63 aged 18–35 years; n = 73 aged 65–90) images of the anterior thigh (dominant) were taken in relaxed supine using B-mode ultrasound imaging. Thickness of muscle, SF and perimuscular fascia were measured, and percentage thickness of total anterior thigh thickness calculated. Independent t-tests compared groups. Correlation between tissue thickness and BMI was examined using Pearson’s coefficient. Muscle thickness was: 39  ±  8 mm in young males, 29  ±  6 mm in females, 25  ±  4 mm in older males and 20  ±  5 mm in females. Percentage muscle to thigh thickness was greater in young participants (p = 0.001). Percentage SF and fascia was 17  ±  6% in young and 26  ±  8% in older males, 32  ±  7% in young and 44  ±  7% in older females. BMI was similar for age and correlated moderately with non-contractile tissue (r = 0.54; p < 0.001) and poorly with muscle (r = −0.01; p = 0.93). In conclusion, this novel application of ultrasound imaging as a simple and rapid means of assessing thigh composition (relative thickness of muscle and non-contractile tissue) may help inform health status, e.g. in older people at risk of frailty and loss of mobility, and aid monitoring effects of weight loss or gain, deconditioning and exercise. (paper)

  12. Completeness of Carotid Intima Media Thickness Measurements Depends on Body Composition: The RADIANCE 1 and 2 trials

    NARCIS (Netherlands)

    Dogan, Soner; Duivenvoorden, Raphaël; Grobbee, E. Diederick; Kastelein, John J. P.; Shear, Charles L.; Evans, Gregory W.; Visseren, Frank L.; Bots, Michiel L.

    2010-01-01

    Aim: Ultrasound protocols to measure carotid intima media thickness (CIMT) differ considerably with regard to the inclusion of the number of carotid segments and angles used. Detailed information on the completeness of CIMT information is often lacking in published reports, and at most, overall

  13. Thick film hydrogen sensor

    Science.gov (United States)

    Hoffheins, Barbara S.; Lauf, Robert J.

    1995-01-01

    A thick film hydrogen sensor element includes an essentially inert, electrically-insulating substrate having deposited thereon a thick film metallization forming at least two resistors. The metallization is a sintered composition of Pd and a sinterable binder such as glass frit. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors.

  14. Esthetic rehabilitation of single anterior edentulous space using fiber-reinforced composite

    Directory of Open Access Journals (Sweden)

    Hyeon Kim

    2014-08-01

    Full Text Available A fiber-reinforced composite (FRC fixed prosthesis is an innovative alternative to a traditional metal restoration, as it is a conservative treatment method. This case report demonstrates a detailed procedure for restoring a missing anterior tooth with an FRC. A 44-year-old woman visited our department with an avulsed tooth that had fallen out on the previous day and was completely dry. This tooth was replanted, but it failed after one year. A semi-direct technique was used to fabricate a FRC fixed partial prosthesis for its replacement. The FRC framework and the pontic were fabricated using a duplicated cast model and nanofilled composite resin. Later on, interproximal contact, tooth shape, and shade were adjusted at chairside. This technique not only enables the clinician to replace a missing tooth immediately after extraction for minimizing esthetic problems, but it also decreases both tooth reduction and cost.

  15. Behaviour of a new composite mesh for the repair of full-thickness abdominal wall defects in a rabbit model.

    Directory of Open Access Journals (Sweden)

    Gemma Pascual

    Full Text Available INTRODUCTION: Composite biomaterials designed for the repair of abdominal wall defects are composed of a mesh component and a laminar barrier in contact with the visceral peritoneum. This study assesses the behaviour of a new composite mesh by comparing it with two latest-generation composites currently used in clinical practice. METHODS: Defects (7x5cm created in the anterior abdominal wall of New Zealand White rabbits were repaired using a polypropylene mesh and the composites: Physiomesh(TM; Ventralight(TM and a new composite mesh with a three-dimensional macroporous polyester structure and an oxidized collagen/chitosan barrier. Animals were sacrificed on days 14 and 90 postimplant. Specimens were processed to determine host tissue incorporation, gene/protein expression of neo-collagens (RT-PCR/immunofluorescence, macrophage response (RAM-11-immunolabelling and biomechanical resistance. On postoperative days 7/14, each animal was examined laparoscopically to quantify adhesions between the visceral peritoneum and implant. RESULTS: The new composite mesh showed the lowest incidence of seroma in the short term. At each time point, the mesh surface covered with adhesions was greater in controls than composites. By day 14, the implants were fully infiltrated by a loose connective tissue that became denser over time. At 90 days, the peritoneal mesh surface was lined with a stable mesothelium. The new composite mesh induced more rapid tissue maturation than Physiomesh(TM, giving rise to a neoformed tissue containing more type I collagen. In Ventralight(TM the macrophage reaction was intense and significantly greater than the other composites at both follow-up times. Tensile strengths were similar for each biomaterial. CONCLUSIONS: All composites showed optimal peritoneal behaviour, inducing good peritoneal regeneration and scarce postoperative adhesion formation. A greater foreign body reaction was observed for Ventralight(TM. All composites induced

  16. Self-assembly of bimetallic AuxPd1-x alloy nanoparticles via dewetting of bilayers through the systematic control of temperature, thickness, composition and stacking sequence

    Science.gov (United States)

    Kunwar, Sundar; Pandey, Puran; Sui, Mao; Bastola, Sushil; Lee, Jihoon

    2018-03-01

    Bimetallic alloy nanoparticles (NPs) are attractive materials for various applications with their morphology and elemental composition dependent optical, electronic, magnetic and catalytic properties. This work demonstrates the evolution of AuxPd1-x alloy nanostructures by the solid-state dewetting of sequentially deposited bilayers of Au and Pd on sapphire (0001). Various shape, size and configuration of AuxPd1‑x alloy NPs are fabricated by the systematic control of annealing temperature, deposition thickness, composition as well as stacking sequence. The evolution of alloy nanostructures is attributed to the surface diffusion, interface diffusion between bilayers, surface and interface energy minimization, Volmer-Weber growth model and equilibrium configuration. Depending upon the temperature, the surface morphologies evolve with the formation of pits, grains and voids and gradually develop into isolated semi-spherical alloy NPs by the expansion of voids and agglomeration of Au and Pd adatoms. On the other hand, small isolated to enlarged elongated and over-grown layer-like alloy nanostructures are fabricated due to the coalescence, partial diffusion and inter-diffusion with the increased bilayer thickness. In addition, the composition and stacking sequence of bilayers remarkably affect the final geometry of AuxPd1‑x nanostructures due to the variation in the dewetting process. The optical analysis based on the UV–vis-NIR reflectance spectra reveals the surface morphology dependent plasmonic resonance, scattering, reflection and absorption properties of AuxPd1‑x alloy nanostructures.

  17. Electron Acceleration in the Field-reversed Configuration (FRC) by Slowly Rotation Odd-parity Magnetic Fields (RMFo)

    International Nuclear Information System (INIS)

    Glasser, A.H.; Cohen, S.A.

    2001-01-01

    The trajectories of individual electrons are studied numerically in a 3D, prolate, FRC [field-reversed configuration] equilibrium magnetic geometry with added small-amplitude, slowly rotating, odd-parity magnetic fields (RMFos). RMFos cause electron heating by toroidal acceleration near the O-point line and by field-parallel acceleration away from it, both followed by scattering from magnetic-field inhomogeneities. Electrons accelerated along the O-point line move antiparallel to the FRC's current and attain average toroidal angular speeds near that of the RMFo, independent of the sense of RMFo rotation. A conserved transformed Hamiltonian, dependent on electron energy and RMFo sense, controls electron flux-surface coordinate

  18. Discrete Calderon’s projections on parallelepipeds and their application to computing exterior magnetic fields for FRC plasmas

    International Nuclear Information System (INIS)

    Kansa, E.; Shumlak, U.; Tsynkov, S.

    2013-01-01

    Confining dense plasma in a field reversed configuration (FRC) is considered a promising approach to fusion. Numerical simulation of this process requires setting artificial boundary conditions (ABCs) for the magnetic field because whereas the plasma itself occupies a bounded region (within the FRC coils), the field extends from this region all the way to infinity. If the plasma is modeled using single fluid magnetohydrodynamics (MHD), then the exterior magnetic field can be considered quasi-static. This field has a scalar potential governed by the Laplace equation. The quasi-static ABC for the magnetic field is obtained using the method of difference potentials, in the form of a discrete Calderon boundary equation with projection on the artificial boundary shaped as a parallelepiped. The Calderon projection itself is computed by convolution with the discrete fundamental solution on the three-dimensional Cartesian grid.

  19. Dual-energy X-ray absorptiometry, skinfold thickness and waist circumference for assessing body composition in ambulant and non-ambulant wheelchair games players

    Directory of Open Access Journals (Sweden)

    Annika eWillems

    2015-11-01

    Full Text Available Field-based assessments provide a cost–effective and accessible alternative to dual-energy X-ray absorptiometry (DXA for practitioners determining body composition in athletic populations. It remains unclear how the range of physical impairments classifiable in wheelchair sports may affect the utility of field-based body composition techniques. The present study assessed body composition using DXA in 14 wheelchair games players who were either wheelchair dependent (non-walkers; n =7 or relied on a wheelchair for sports participation only (walkers; n =7. Anthropometric measurements were used to predict body fat percentage with existing regression equations established for able-bodied persons by Sloan & Weir, Durnin & Womersley, Lean et al, Gallagher et al and Pongchaiyakul et al. In addition, linear regression analysis was performed to calculate the association between body fat percentage and BMI, waist circumference, sum of 6 skinfold thicknesses and sum of 8 skinfold thicknesses. Results showed that non-walkers had significantly lower total lean tissue mass (46.2±=6.6 kg vs. 59.4±8.2 kg, P =.006 and total body mass (65.8 ±4.2 kg vs. 79.4 ±14.9 kg; P =0.05 than walkers. Body fat percentage calculated from most existing regression equations was significantly lower than that from DXA, by 2 to 9% in walkers and 8 to14% in non-walkers. Of the anthropometric measurements, the sum of 8 skinfold thicknesses had the lowest standard error of estimation in predicting body fat content. In conclusion, existing anthropometric equations developed in able-bodied populations substantially underestimated body fat content in wheelchair athletes, particularly non-walkers. Impairment specific equations may be needed in wheelchair athletes.

  20. Influences of carbon content and coating carbon thickness on properties of amorphous CoSnO{sub 3}@C composites as anode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Fuqiang [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); Fang, Guoqing [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); Changzhou Institute of Energy Storage Materials and Devices, Changzhou 213000 (China); Zhang, Ruixue [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); Xu, Yanhui; Zheng, Junwei [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006 (China); Li, Decheng, E-mail: lidecheng@suda.edu.cn [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006 (China)

    2014-08-30

    Highlights: • The thickness of carbon coating layers can be successfully controlled through varying molar concentration of aqueous glucose solution. • Coating carbon thickness and carbon content are two important factors on the electrochemical performances of CoSnO3@C. • CoSnO{sub 3}@C under optimized conditions exhibits the optimal balance between the volume buffering effect and reversible capacity. • As-prepared CoSnO{sub 3}@C under optimized conditions shows excellent electrochemical performances, whose reversible capacity could reach 491 mA h g{sup −1} after 100 cycles. - Abstract: A series of core–shell carbon coated amorphous CoSnO{sub 3} (CoSnO{sub 3}@C) with different carbon content are synthesized. Effects of carbon content and coating carbon thickness on the physical and electrochemical performances of the samples were studied in detail. The samples were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), galvanostatic charge–discharge and AC impedance spectroscopy, respectively. The results indicate that controlling the concentration of aqueous glucose solution influences the generation of in-situ carbon layer thickness. The optimal concentration of aqueous glucose solution, carbon content and carbon layer thickness are suggested as 0.25 M, 35.1% and 20 nm, respectively. CoSnO{sub 3}@C composite prepared under the optimal conditions exhibits excellent cycling performance, whose reversible capacity could reach 491 mA h g{sup −1} after 100 cycles.

  1. A fiber-reinforced composite prosthesis restoring a lateral midfacial defect: a clinical report.

    Science.gov (United States)

    Kurunmäki, Hemmo; Kantola, Rosita; Hatamleh, Muhanad M; Watts, David C; Vallittu, Pekka K

    2008-11-01

    This clinical report describes the use of a glass fiber-reinforced composite (FRC) substructure to reinforce the silicone elastomer of a large facial prosthesis. The FRC substructure was shaped into a framework and embedded into the silicone elastomer to form a reinforced facial prosthesis. The prosthesis is designed to overcome the disadvantages associated with traditionally fabricated prostheses; namely, delamination of the silicone of the acrylic base, poor marginal adaptation over time, and poor simulation of facial expressions.

  2. Long pulse FRC sustainment with enhanced edge driven rotating magnetic field current drive

    International Nuclear Information System (INIS)

    Hoffman, A.L.; Guo, H.Y.; Miller, K.E.; Milroy, R.D.

    2005-01-01

    FRCs have been formed and sustained for up to 50 normal flux decay times by Rotating Magnetic Fields (RMF) in the TCS experiment. For these longer pulse times a new phenomenon has been observed: switching to a higher performance mode delineated by shallower RMF penetration, higher ratios of generated poloidal to RMF drive field, and lower overall plasma resistivity. This global data is not explainable by previous RMF theory based on uniform electron rotational velocities or by numerical calculations based on uniform plasma resistivity, but agrees in many respects with new calculations made using strongly varying resistivity profiles. In order to more realistically model RMF driven FRCs with such non-uniform resistivity profiles, a double rigid rotor model has been developed with separate inner and outer electron rotational velocities and resistivities. The results of this modeling suggest that the RMF drive results in very high resistivity in a narrow edge layer, and that the higher performance mode is characterized by a sharp reduction in resistivity over the bulk of the FRC. (author)

  3. High Energy Research and Applications (HERA) Pulsed Power and Pulsed Power Systems R&D for Magnetized Target Fusion Using Field Reversed Configurations (MTF-FRC)

    Science.gov (United States)

    2013-03-12

    that we also advocate for potentially increasing the plasma lifetime. The first is the use of a coaxial plasma gun on axis to effectively bias the FRC...of their FRC plasmas by a factor of three over what had been achieved before using the gun . Admittedly, their plasmas are larger and lower density...were able to show, by the use of the plasma gun , that distortion and centering improved dramatically, and this stabilization is believed to be a major

  4. The effect of film thickness and molecular structure on order and disorder in thin films of compositionally asymmetric block copolymers

    Science.gov (United States)

    Mishra, Vindhya

    Directed self-assembly of thin film block copolymers offer a high throughput-low cost route to produce next generation lithographic devices, if one can bring the defect densities in the self assembled patterns below tolerance limits. However, the ability to control the nanoscale structure or morphology in thin film block copolymers presents challenges due to confinement effects on equilibrium behavior. Using structure characterization techniques such as grazing incidence small angle X-ray scattering (GISAXS), transmission electron and atomic force microscopy as well as self-consistent field theory, we have investigated how film thickness, annealing temperature and block copolymer structure affects the equilibrium behavior of asymmetric block copolymer films. Our studies have revealed the complicated dependence of order-disorder transitions, order-order transitions and symmetry transitions on film thickness. We found that the thickness dependent transition in the packing symmetry of spherical morphology diblock copolymers can be suppressed by blending with a small amount of majority block homopolymer, which allowed us to resolve the driving force behind this transition. Defect densities in, and the order-disorder transition temperature of, thin films of graphoepitaxially aligned diblock copolymer cylinders showed surprising sensitivity to the microdomain spacing. Methods to mitigate defect formation in thin films have been identified. The challenge of quantification of structural order in these systems was overcome using GISAXS, which allowed us to study the phenomena of disordering in two and three dimensions. Through studies on block copolymers which exhibit an order-order transition in bulk, we found that that subtle differences in the packing frustration of the spherical and cylindrical phases as well as the higher configurational entropy of free chain ends at the surface can drive the equilibrium configuration in thin films away from the stable bulk structure

  5. Effect of ultraviolet light irradiation period on bond strengths between fiber-reinforced composite post and core build-up composite resin.

    Science.gov (United States)

    Asakawa, Yuya; Takahashi, Hidekazu; Iwasaki, Naohiko; Kobayashi, Masahiro

    2014-01-01

    The aim of the present study was to characterize the effects of the ultraviolet light (UV) irradiation period on the bond strength of fiber-reinforced composite (FRC) posts to core build-up resin. Three types of FRC posts were prepared using polymethyl methacrylate, urethane dimethacrylate, and epoxy resin. The surfaces of these posts were treated using UV irradiation at a distance of 15 mm for 0 to 600 s. The pull-out bond strength was measured and analyzed with the Dunnett's comparison test (α=0.05). The bond strengths of the post surfaces without irradiation were 6.9 to 7.4 MPa; those after irradiation were 4.2 to 26.1 MPa. The bond strengths significantly increased after 15 to 120-s irradiation. UV irradiation on the FRC posts improved the bond strengths between the FRC posts and core build-up resin regardless of the type of matrix resin.

  6. Large-area, lightweight and thick biomimetic composites with superior material properties via fast, economic, and green pathways.

    Science.gov (United States)

    Walther, Andreas; Bjurhager, Ingela; Malho, Jani-Markus; Pere, Jaakko; Ruokolainen, Janne; Berglund, Lars A; Ikkala, Olli

    2010-08-11

    Although remarkable success has been achieved to mimic the mechanically excellent structure of nacre in laboratory-scale models, it remains difficult to foresee mainstream applications due to time-consuming sequential depositions or energy-intensive processes. Here, we introduce a surprisingly simple and rapid methodology for large-area, lightweight, and thick nacre-mimetic films and laminates with superior material properties. Nanoclay sheets with soft polymer coatings are used as ideal building blocks with intrinsic hard/soft character. They are forced to rapidly self-assemble into aligned nacre-mimetic films via paper-making, doctor-blading or simple painting, giving rise to strong and thick films with tensile modulus of 45 GPa and strength of 250 MPa, that is, partly exceeding nacre. The concepts are environmentally friendly, energy-efficient, and economic and are ready for scale-up via continuous roll-to-roll processes. Excellent gas barrier properties, optical translucency, and extraordinary shape-persistent fire-resistance are demonstrated. We foresee advanced large-scale biomimetic materials, relevant for lightweight sustainable construction and energy-efficient transportation.

  7. Equivalent network for resistance and temperature coefficient of resistance versus temperature and composition of thick resistive films

    International Nuclear Information System (INIS)

    Kusy, A.

    1987-01-01

    Two types of elementary resistances in thick resistive films have been considered: (i) constriction resistance R/sub C/ determined by the bulk properties of conducting material and by the geometry of constriction, and (ii) barrier resistance R/sub B/ determined by the parameters of a thermally activated type of tunneling process and by the geometry of the metal-insulator-metal unit. On this basis a resistance network composed of a large number of the two types of resistances has been defined. The network has been considered as being equivalent to thick resistive film (TRF) from the point of view of the resistance and temperature coefficient of resistance (TCR). The parameters of this network have been evaluated by the computer-aided approximation of the experimental data found for RuO 2 -based TRFs. On the basis of the equations derived for the network as well as the results of the approximation process, it can be concluded that the small values of the network TCR result from the superposition of the TCR of the conducting component β/sub C/ and of the temperature coefficient of barrier resistance α/sub B/. In this superposition β/sub C/ is attenuated (by 1--2 orders of magnitude), while α/sub B/ is attenuated by only few percentages. The network has been found to be strongly barrier dominated

  8. Design of laser-driven SiO2-YAG:Ce composite thick film: Facile synthesis, robust thermal performance, and application in solid-state laser lighting

    Science.gov (United States)

    Xu, Jian; Liu, Bingguo; Liu, Zhiwen; Gong, Yuxuan; Hu, Baofu; Wang, Jian; Li, Hui; Wang, Xinliang; Du, Baoli

    2018-01-01

    In recent times, there have been rapid advances in the solid-state laser lighting technology. Due to the large amounts of heat accumulated from the high flux laser radiation, color conversion materials used in solid-state laser lighting devices should possess high durability, high thermal conductivity, and low thermal quenching. The aim of this study is to develop a thermally robust SiO2-YAG:Ce composite thick film (CTF) for high-power solid-state laser lighting applications. Commercial colloidal silica which was used as the source of SiO2, played the roles of an adhesive, a filler, and a protecting agent. Compared to the YAG:Ce powder, the CTF exhibits remarkable thermal stability (11.3% intensity drop at 200 °C) and durability (4.5% intensity drop after 1000 h, at 85 °C and 85% humidity). Furthermore, the effects of the substrate material and the thickness of the CTF on the laser lighting performance were investigated in terms of their thermal quenching and luminescence saturation behaviors, respectively. The CTF with a thickness of 50 μm on a sapphire substrate does not show luminescence saturation, despite a high-power density of incident radiation i.e. 20 W/mm2. These results demonstrate the potential applicability of the CTF in solid-state laser lighting devices.

  9. Constitutive modeling of fiber-reinforced cement composites

    Science.gov (United States)

    Boulfiza, Mohamed

    The role of fibers in the enhancement of the inherently low tensile stress and strain capacities of fiber reinforced cementitious composites (FRC) has been addressed through both the phenomenological, using concepts of continuum damage mechanics, and micro-mechanical approaches leading to the development of a closing pressure that could be used in a cohesive crack analysis. The observed enhancements in the matrix behavior is assumed to be related to the ability of the material to transfer stress across cracks. In the micromechanics approach, this is modeled by the introduction of a nonlinear closing pressure at the crack lips. Due to the different nature of cracking in the pre-peak and post peak regimes, two different micro-mechanical models of the cohesive pressure have been proposed, one for the strain hardening stage and another for the strain softening regime. This cohesive pressure is subsequently incorporated into a finite element code so that a nonlinear fracture analysis can be carried out. On top of the fact that a direct fracture analysis has been performed to predict the response of some FRC structural elements, a numerical procedure for the homogenization of FRC materials has been proposed. In this latter approach, a link is established between the cracking taking place at the meso-scale and its mechanical characteristics as represented by the Young's modulus. A parametric study has been carried out to investigate the effect of crack patterning and fiber volume fractions on the overall Young's modulus and the thermodynamic force associated with the tensorial damage variable. After showing the usefulness and power of phenomenological continuum damage mechanics (PCDM) in the prediction of ERC materials' response to a stimuli (loading), a combined PCDM-NLFMsp1 approach is proposed to model (predict, forecast) the complete response of the composite up to failure. Based on experimental observations, this approach assumes that damage mechanics which predicts

  10. Effect of Material Parameters on Steady State Creep in a Thick Composite Cylinder Subjected to Internal Pressure

    Directory of Open Access Journals (Sweden)

    Tejeet Singh

    2009-12-01

    Full Text Available The steady state creep in Al- SiCP composite cylinder subjected to internal pressure was investigated. The creep behavior of the material were described by threshold stress based creep law by assuming a stress exponent of 5. The effect of size and content of the reinforcement (SiCP , and operating temperature on the stresses and strain rates in the composite cylinder were investigated. The stresses in the cylinder did not have significant variation with varying size and content of the reinforcement, and operating temperature. However, the tangential as well as radial strain rates in the cylinder could be reduced to a significant extent by decreasing size of SiCP, increasing the content of SiCP and decreasing operating temperature.

  11. Optimization of wall thickness and lay-up for the shell-like composite structure loaded by non-uniform pressure field

    Science.gov (United States)

    Shevtsov, S.; Zhilyaev, I.; Oganesyan, P.; Axenov, V.

    2017-01-01

    The glass/carbon fiber composites are widely used in the design of various aircraft and rotorcraft components such as fairings and cowlings, which have predominantly a shell-like geometry and are made of quasi-isotropic laminates. The main requirements to such the composite parts are the specified mechanical stiffness to withstand the non-uniform air pressure at the different flight conditions and reduce a level of noise caused by the airflow-induced vibrations at the constrained weight of the part. The main objective of present study is the optimization of wall thickness and lay-up of composite shell-like cowling. The present approach assumes conversion of the CAD model of the cowling surface to finite element (FE) representation, then its wind tunnel testing simulation at the different orientation of airflow to find the most stressed mode of flight. Numerical solutions of the Reynolds averaged Navier-Stokes (RANS) equations supplemented by k-w turbulence model provide the spatial distributions of air pressure applied to the shell surface. At the formulation of optimization problem the global strain energy calculated within the optimized shell was assumed as the objective. A wall thickness of the shell had to change over its surface to minimize the objective at the constrained weight. We used a parameterization of the problem that assumes an initiation of auxiliary sphere with varied radius and coordinates of the center, which were the design variables. Curve that formed by the intersection of the shell with sphere defined boundary of area, which should be reinforced by local thickening the shell wall. To eliminate a local stress concentration this increment was defined as the smooth function defined on the shell surface. As a result of structural optimization we obtained the thickness of shell's wall distribution, which then was used to design the draping and lay-up of composite prepreg layers. The global strain energy in the optimized cowling was reduced in2

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

    Science.gov (United States)

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

    2009-06-01

    A method has recently been developed for producing fibre-reinforced composites (FRC) with porous surfaces, intended for use as load-bearing orthopaedic implants. This study focuses on evaluation of the bone-bonding behaviour of FRC implants. Three types of cylindrical implants, i.e. FRC implants with a porous surface, solid polymethyl methacrylate (PMMA) implants and titanium (Ti) implants, were inserted in a transverse direction into the intercondular trabeculous bone area of distal femurs and proximal tibias of New Zealand White rabbits. Animals were sacrificed at 3, 6 and 12 weeks post operation, and push-out tests (n=5-6 per implant type per time point) were then carried out. At 12 weeks the shear force at the porous FRC-bone interface was significantly higher (283.3+/-55.3N) than the shear force at interfaces of solid PMMA/bone (14.4+/-11.0 N; pshielding effect.

  13. FRC [field-reversed configuration] translation studies on FRX-C/LSM

    International Nuclear Information System (INIS)

    Rej, D.; Barnes, G.; Baron, M.

    1989-01-01

    In preparation for upcoming compression-heating experiments, field-reversed configurations (FRCs) have been translated out of the FRX-C/LSM θ-pinch source, and into the 0.4-m-id, 6.7-m-long translation region formerly used on FRX-C/T. Unlike earlier experiments FRCs are generated without magnetic tearing in the larger FRX-C/LSM source (nominal coil id = 0.70 m, length = 2 m); larger, lower-energy-density FRCs are formed: r/sub s/ ≅ 0.17 m, B/sub ext/ ≅ 0.35 T, ≅ 7 /times/ 10 20 m/sup /minus/3/ and T/sub e/ + T/sub i/ ≅ 400 eV. An initial 3-mtorr D 2 pressure is introduced by either static or puff fill. Asymmetric fields from auxiliary end coils (used for non-tearing formation) provide the accelerating force on the FRC, thereby eliminating the need for a conical θ-pinch coil. An important feature is the abrupt 44% decrease in the flux-conserving wall radius at the transition between the θ-pinch and translation region, similar to that in the compressor. In this paper we review a variety of issues addressed by the recent translation experiments: translation dynamics; translation through a modulated magnetic field; stabilization of the n = 2 rotational instability by weak helical quadrupole fields; and confinement properties. Results from internal magnetic field measurements in translating FRCs may be found in a companion paper. 10 refs., 5 figs

  14. Mechanical properties of fiber reinforced restorative composite with two distinguished fiber length distribution.

    Science.gov (United States)

    Lassila, Lippo; Garoushi, Sufyan; Vallittu, Pekka K; Säilynoja, Eija

    2016-07-01

    The purpose of this study was to investigate the reinforcing effect of discontinuous glass fiber fillers with different length scales on fracture toughness and flexural properties of dental composite. Experimental fiber reinforced composite (Exp-FRC) was prepared by mixing 27wt% of discontinuous E-glass fibers having two different length scales (micrometer and millimeter) with various weight ratios (1:1, 2:1, 1:0 respectively) to the 23wt% of dimethacrylate based resin matrix and then 50wt% of silane treated silica filler were added gradually using high speed mixing machine. As control, commercial FRC and conventional posterior composites were used (everX Posterior, Alert, and Filtek Superme). Fracture toughness, work of fracture, flexural strength, and flexural modulus were determined for each composite material following ISO standards. The specimens (n=6) were dry stored (37°C for 2 days) before they were tested. Scanning electron microscopy was used to evaluate the microstructure of the experimental FRC composites. The results were statistically analyzed using ANOVA followed by post-hoc Tukey׳s test. Level of significance was set at 0.05. ANOVA revealed that experimental composites reinforced with different fiber length scales (hybrid Exp-FRC) had statistically significantly higher mechanical performance of fracture toughness (4.7MPam(1/2)) and flexural strength (155MPa) (plength scales of discontinues fiber fillers (hybrid) with polymer matrix yielded improved mechanical performance compared to commercial FRC and conventional posterior composites. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Influence of functional group on the electrical transport properties of polyvinyl alcohol grafted multiwall carbon nanotube composite thick film

    Science.gov (United States)

    Kumar Das, Amit; Dharmana, Reuben; Mukherjee, Ayan; Baba, Koumei; Hatada, Ruriko; Kumar Meikap, Ajit

    2018-04-01

    We present a novel technique to obtain a higher or lower value of dielectric constant due to the variation of a functional group on the surface of multiwall carbon nanotube (MWCNTs) for a polyvinyl alcohol (PVA) grafted MWCNT system. We have prepared PVA grafted pristine and different types of functionalized (-COOH, -OH, and -NH2) MWCNT nanocomposite films. The strong interfacial interaction between the host PVA matrix and nanofiller is characterized by different experimental techniques. The frequency variation of the electrical transport properties of the composite films is investigated in a wide temperature range (303 ≤ T ≤ 413 K) and frequency range (20 Hz ≤ f ≤ 1 MHz). The dielectric constant of the amine (-NH2) functionalized MWCNT incorporated PVA film is about 2 times higher than that of the pristine MWCNT embedded PVA film. The temperature variation of the dielectric constant shows an anomalous behaviour. The modified Cole-Cole equation simulated the experimentally observed dielectric spectroscopy at high temperature. The ac conductivity of the composite films obeys the correlated barrier hopping model. The imaginary part of the electric modulus study shows the ideal Debye-type behaviour at low frequency and deviation of that at high frequency. To illustrate the impedance spectroscopy of the nanocomposite films, we have proposed an impedance based battery equivalent circuit model. The current-voltage characteristic shows hysteresis behaviour of the nanocomposite films. The trap state height for all composite films is evaluated by simulating the current density-electric field data with the Poole-Frenkel emission model. This investigation opens a new avenue for designing electronic devices with a suitable combination of cost effective soft materials.

  16. Density, thickness and composition measurements of TiO2 -SiO2 thin films by coupling X-ray reflectometry, ellipsometry and electron probe microanalysis-X

    International Nuclear Information System (INIS)

    Hodroj, A.; Roussel, H.; Crisci, A.; Robaut, F.; Gottlieb, U.; Deschanvres, J.L.

    2006-01-01

    Mixed TiO 2 -SiO 2 thin films were deposited by aerosol atmospheric CVD method by using di-acetoxi di-butoxi silane (DADBS) and Ti tetra-butoxide as precursors. By varying the deposition temperatures between 470 and 600 deg. C and the ratios between the Si and Ti precursors (Si/Ti) from 2 up to 16, films with different compositions and thicknesses were deposited. The coupled analysis of the results of different characterisation methods was used in order to determine the variation of the composition, the thickness and the density of the films. First EPMA measurements were performed at different acceleration voltages with a Cameca SX50 system. By analysing, with specific software, the evolution of the intensity ratio I x /I std versus the voltage, the composition and the mass thickness (product of density by the thickness) were determined. In order to measure independently the density, X-ray reflectometry experiments were performed. By analysing the value of the critical angle and the Kiessig fringes, the density and the thickness of the layers were determined. The refractive index and the thickness of the films were also measured by ellipsometry. By assuming a linear interpolation between the index value of the pure SiO 2 and TiO 2 films, the film composition was deduced from the refractive index value. XPS measurements were also performed in order to obtain an independent value of the composition. A good agreement between the ways to measure the density is obtained

  17. Joining of thin thickness SiCf/SiC composites: research of a joining composition and of an associated elaboration process

    International Nuclear Information System (INIS)

    Jacques, E.

    2012-01-01

    The present work is part of the Fourth Generation Fast Reactors program. One of the key issues is the joining of the SiC f /SiC ceramic matrix composites (CMC) to seal the combustible cladding. At the present time, no chemical composition as a joint is refractive enough to face the expected operating temperatures. The aims of this study are the following: (1) the identification of a joining composition and its associated elaboration process answering the specifications, (2) the validation of a local and fast heating process and (3) the definition of mechanical tests to characterise these joinings. We describe the methodology and the results for joining SiC and SiC f /SiC substrates at solid and liquid state using metallic silicides. Joint integrity and joint strength can be improved by adding small SiC particles to the silicides powders. Chemical reactivity, wettability tests and thermomechanical properties analysis have been carried out on the joints. Cross sections of the assembly were prepared to study the joint/substrate chemical bonding, the cracking and the crack deflection in the vicinity of the interface. Also, one of the challenge consists in using a local heating at a high temperature (around 1800 C) for a short time to avoid the degradation of the composite structure. The assemblies have been then performed in an inductive furnace but in order to prepare the joining technology, trials of local heating have also been investigated with a CO 2 laser beam and a microwave generator. Finally, descriptions of the 4-points bending mechanical test used and the associated results are presented. (author) [fr

  18. Thickness-self-controlled synthesis of porous transparent polyaniline-reduced graphene oxide composites towards advanced bifacial dye-sensitized solar cells

    Science.gov (United States)

    Wang, Yu-Sheng; Li, Shin-Ming; Hsiao, Sheng-Tsung; Liao, Wei-Hao; Yang, Shin-Yi; Tien, Hsi-Wen; Ma, Chen-Chi M.; Hu, Chi-Chang

    2014-08-01

    A powerful synthesis strategy is proposed for fabricating porous polyaniline-reduced graphene oxide (PANI-RGO) composites with transparency up to 80% and thickness from 300 to 1000 nm for the counter electrode (CE) of bifacial dye-sensitizing solar cells (DSSCs). The first step is to combine the in-situ positive charge transformation of graphene oxide (GO) through aniline (ANI) prepolymerization and the electrostatic adsorption of ANI oligomer-GO to effectively control the thickness of ultrathin PANI-GO films by adjusting pH of the polymerization media. In the second step, PANI-GO films are reduced with hydroiodic acid to simultaneously enhance the apparent redox activity for the I3-/I- couple and their electronic conductivity. Incorporating the RGO increases the transparency of PANI and facilitates the light-harvesting from the rear side. A DSSC assembled with such a transparent PANI-RGO CE exhibits an excellent efficiency of 7.84%, comparable to 8.19% for a semi-transparent Pt-based DSSC. The high light-harvesting ability of PANI-RGO enhances the efficiency retention between rear- and front-illumination modes to 76.7%, compared with 69.1% for a PANI-based DSSC. The higher retention reduces the power-to-weight ratio and the total cost of bifacial DSSCs, which is also promising in other applications, such as windows, power generators, and panel screens.

  19. Hair Follicle Morphogenesis in the Treatment of Mouse Full-Thickness Skin Defects Using Composite Human Acellular Amniotic Membrane and Adipose Derived Mesenchymal Stem Cells

    Directory of Open Access Journals (Sweden)

    Wu Minjuan

    2016-01-01

    Full Text Available Early repair of skin injury and maximal restoration of the function and appearance have become important targets of clinical treatment. In the present study, we observed the healing process of skin defects in nude mice and structural characteristics of the new skin after transplantation of isolated and cultured adipose derived mesenchymal stem cells (ADMSCs onto the human acellular amniotic membrane (AAM. The result showed that ADMSCs were closely attached to the surface of AAM and grew well 24 h after seeding. Comparison of the wound healing rate at days 7, 14, and 28 after transplantation showed that ADMSCs seeded on AAM facilitated the healing of full-thickness skin wounds more effectively as compared with either hAM or AAM alone, indicating that ADMSCs participated in skin regeneration. More importantly, we noticed a phenomenon of hair follicle development during the process of skin repair. Composite ADMSCs and AAM not only promoted the healing of the mouse full-thickness defects but also facilitated generation of the appendages of the affected skin, thus promoting restoration of the skin function. Our results provide a new possible therapy idea for the treatment of skin wounds with respect to both anatomical regeneration and functional restoration.

  20. High Flux FRC Facility for the Stability, Confinement and ITER Divertor Studies

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, Alan L. [Univ. of Washington, Seattle, WA (United States). Aerospace and Energetics Research Program. Redmond Plasma Physics Lab.; Milroy, Richard D. [Univ. of Washington, Seattle, WA (United States). Aerospace and Energetics Research Program. Redmond Plasma Physics Lab.

    2014-01-31

    The TCS (Translation, Confinement, & Sustainment) program was begun on 7 August, 1996 to renew basic studies of the Field Reversed Configuration (FRC). The program made use of the old LSX (Large s Experiment) device, which was constructed at STI during the period from 1986 to 1990, but only operated for one year due to a DOE decision at the time to focus exclusively on the tokamak configuration. LSX was transferred to the University of Washington in 1992 and modified (LSX/mod) to perform Tokamak Refueling by Accelerated Plasmoids (TRAP) experiments. The TRAP program was funded from 7 August, 1992 until 6 August, 1996, but was utilized for an additional year while TCS was being constructed. During the first TCS funding period TCS was completed and initial experiments were begun. A large multi-megawatt RF power supply was built by Los Alamos National Laboratory (LANL) for use with a Rotating Magnetic Field (RMF) system, and LANL has been a continuing participant in our experimental program. A smaller prototype facility, called the Star Thrust Experiment (STX) was also built and operated in this period, partly with NASA funding, before TCS came on-line. A final report for this construction period was submitted in September 2000. A first renewal period (2.5 years) provided operating funds for the period between July 7, 2000 and January 6, 2003. A great deal of progress was made in understanding the use of RMF to both form and sustain FRCs during this period. The principal result of the experimental program was the formation of quasi steady-state (as long as RMF power was available) FRCs with densities in the 1-3x1019 m-3 range. However, the plasma temperature (Te or Ti) was limited to sub-25 eV, except transiently during start-up, by the rapid accumulation of impurities. This is not surprising since TCS was only designed to demonstrate RMF flux build-up and was not provided with either fueling capabilities or modern vacuum

  1. Innovative Structural Materials and Sections with Strain Hardening Cementitious Composites

    Science.gov (United States)

    Dey, Vikram

    The motivation of this work is based on development of new construction products with strain hardening cementitious composites (SHCC) geared towards sustainable residential applications. The proposed research has three main objectives: automation of existing manufacturing systems for SHCC laminates; multi-level characterization of mechanical properties of fiber, matrix, interface and composites phases using servo-hydraulic and digital image correlation techniques. Structural behavior of these systems were predicted using ductility based design procedures using classical laminate theory and structural mechanics. SHCC sections are made up of thin sections of matrix with Portland cement based binder and fine aggregates impregnating continuous one-dimensional fibers in individual or bundle form or two/three dimensional woven, bonded or knitted textiles. Traditional fiber reinforced concrete (FRC) use random dispersed chopped fibers in the matrix at a low volume fractions, typically 1-2% to avoid to avoid fiber agglomeration and balling. In conventional FRC, fracture localization occurs immediately after the first crack, resulting in only minor improvement in toughness and tensile strength. However in SHCC systems, distribution of cracking throughout the specimen is facilitated by the fiber bridging mechanism. Influence of material properties of yarn, composition, geometry and weave patterns of textile in the behavior of laminated SHCC skin composites were investigated. Contribution of the cementitious matrix in the early age and long-term performance of laminated composites was studied with supplementary cementitious materials such as fly ash, silica fume, and wollastonite. A closed form model with classical laminate theory and ply discount method, coupled with a damage evolution model was utilized to simulate the non-linear tensile response of these composite materials. A constitutive material model developed earlier in the group was utilized to characterize and

  2. Using Fourier and Taylor series expansion in semi-analytical deformation analysis of thick-walled isotropic and wound composite structures

    Directory of Open Access Journals (Sweden)

    Jiran L.

    2016-06-01

    Full Text Available Thick-walled tubes made from isotropic and anisotropic materials are subjected to an internal pressure while the semi-analytical method is employed to investigate their elastic deformations. The contribution and novelty of this method is that it works universally for different loads, different boundary conditions, and different geometry of analyzed structures. Moreover, even when composite material is considered, the method requires no simplistic assumptions. The method uses a curvilinear tensor calculus and it works with the analytical expression of the total potential energy while the unknown displacement functions are approximated by using appropriate series expansion. Fourier and Taylor series expansion are involved into analysis in which they are tested and compared. The main potential of the proposed method is in analyses of wound composite structures when a simple description of the geometry is made in a curvilinear coordinate system while material properties are described in their inherent Cartesian coordinate system. Validations of the introduced semi-analytical method are performed by comparing results with those obtained from three-dimensional finite element analysis (FEA. Calculations with Fourier series expansion show noticeable disagreement with results from the finite element model because Fourier series expansion is not able to capture the course of radial deformation. Therefore, it can be used only for rough estimations of a shape after deformation. On the other hand, the semi-analytical method with Fourier Taylor series expansion works very well for both types of material. Its predictions of deformations are reliable and widely exploitable.

  3. Thick Toenails

    Science.gov (United States)

    ... in individuals with nail fungus (onychomycosis), psoriasis and hypothyroidism. Those who have problems with the thickness of their toenails should consult a foot and ankle surgeon for proper diagnosis and treatment. Find an ACFAS Physician Search Search Tools Find ...

  4. [Influence of retainer design on fixation strength of resin-bonded glass fiber reinforced composite fixed cantilever dentures].

    Science.gov (United States)

    Petrikas, O A; Voroshilin, Iu G; Petrikas, I V

    2013-01-01

    Fiber-reinforced composite (FRC) fixed partial dentures (FPD) have become an accepted part of the restorative dentist's armamentarium. The aim of this study was to evaluate in vitro the influence of retainer design on the strength of two-unit cantilever resin-bonded glass FRC-FPDs. Four retainer designs were tested: a dual wing, a dual wing + horizontal groove, a dual wing + occlusal rest and a step-box. Of each design on 7 human mandibular molars, FRC-FPDs of a premolar size were produced. The FRC framework was made of resin Revolution (Kerr) impregnated glass fibers (GlasSpan, GlasSpan) and veneered with hybrid resin composite (Charisma, Kulzer). Revolution (Kerr) was used as resin luting cement. FRC-FPDs were loaded to failure in a universal testing machine. T (Student's)-test was used to evaluate the data. The four designs were analyzed with finite element analysis (FEA) to reveal the stress distribution within the tooth/restoration complex. Significantly lower fracture strengths were observed with inlay-retained FPDs (step-box: 172±11 N) compared to wing-retained FPDs (poptimal design for replacement of a single premolar by means of a two-unit cantilever FRC-FPDs.

  5. A comparative evaluation of fracture resistance of endodontically treated teeth, with variable marginal ridge thicknesses, restored with composite resin and composite resin reinforced with Ribbond: An in vitro study

    Directory of Open Access Journals (Sweden)

    Vaishali Kalburge

    2013-01-01

    Full Text Available Background: The anatomic shape of maxillary premolars show a tendency towards separation of their cusps during mastication after endodontic treatment. Preservation of the marginal ridge of endodontically treated and restored premolars can act as a strengthening factor and improve the fracture resistance. Objectives: To evaluate the effect of varying thickness of marginal ridge on the fracture resistance of endodontically treated maxillary premolars restored with composite and Ribbond reinforced composites. Materials and Methods: One hundred and twenty, freshly extracted, non carious human mature maxillary premolars were selected for this experimental in vitro study. The teeth were randomly assigned in to twelve groups ( n = 10. Group 1 received no preparation. All the premolars in other groups were root canal treated. In subgroups of 3 and 4, DO cavities were prepared while MOD cavities were prepared for all subgroups of group 2, the dimensions of the proximal boxes were kept uniform. In group 3 and 4 the dimensions of the mesial marginal ridge were measured using a digital Vernier caliper as 2 mm, 1.5 mm, 1 mm and 0.5 mm in the respective subgroups. All samples in groups 2.2 and all the subgroups of 3 were restored with a dentin bonding agent and resin composite. The teeth in group 2.3 and all subgroups of 4 were restored with composite reinforced with Ribbond fibers. The premolars were submitted to axial compression up to failure at 45 degree angle to a palatal cusp in universal testing machine. The mean load necessary to fracture was recorded in Newtons and the data was analysed. Results: There was a highly significant difference between mean values of force required to fracture teeth in group 1 and all subgroups of group 2, 3 and 4 (i.e., P < 0.01 Conclusion: On the basis of static loading, preserving the mesial marginal ridge with thicknesses of mm, 1.5 mm, 1 mm and 0.5 mm, composite restored and Ribbond reinforced composite restored

  6. Quaternary volcanism near the Valley of Mexico: implications for subduction zone magmatism and the effects of crustal thickness variations on primitive magma compositions

    Science.gov (United States)

    Wallace, Paul J.; Carmichael, Ian S. E.

    The Valley of Mexico and surrounding regions of Mexico and Morelos states in central Mexico contain more than 250 Quaternary eruptive vents in addition to the large, composite volcanoes of Popocatépetl, Iztaccíhuatl, and Nevado de Toluca. The eruptive vents include cinder and lava cones, shield volcanoes, and isolated andesitic and dacitic lava flows, and are most numerous in the Sierra Chichináutzin that forms the southern terminus of the Valley of Mexico. The Chichináutzin volcanic field (CVF) is part of the E-W-trending Mexican Volcanic Belt (MVB), a subduction-related volcanic arc that extends across Mexico. The crustal thickness beneath the CVF ( 50km) is the greatest of any region in the MVB and one of the greatest found in any arc worldwide. Lavas and scoriae erupted from vents in the CVF include alkaline basalts and calc-alkaline basaltic andesites, andesites, and dacites. Both alkaline and calc-alkaline groups contain primitive varieties that have whole rock Mg#, MgO, and Ni contents, and liquidus olivine compositions (<=Fo90) that are close to those expected of partial melts from mantle peridotite. Primitive varieties also show a wide range of incompatible trace element abundances (e.g. Ba 210-1080ppm Ce 25-100ppm Zr 130-280ppm). Data for primitive calc-alkaline rocks from both the CVF and other regions of the MVB to the west are consistent with magma generation in an underlying mantle wedge that is depleted in Ti, Zr, and Nb and enriched in large ion lithophile (K, Ba, Rb) and light rare earth (La, Ce) elements. Extents of partial melting estimated from Ti and Zr data are lower for primitive calc-alkaline magmas in the CVF than for those from the regions of the MVB to the west where the crust is thinner. The distinctive major element compositions (low CaO and Al2O3, high SiO2) of the primitive calc-alkaline magmas in the CVF indicate a more refractory mantle source beneath this region of thick crust. In contrast, primitive alkaline magmas from the

  7. Structural optimization of the fibre-reinforced composite substructure in a three-unit dental bridge.

    Science.gov (United States)

    Shi, Li; Fok, Alex S L

    2009-06-01

    Failures of fixed partial dentures (FPDs) made of fibre-reinforced composites (FRC) have been reported in many clinical and in vitro studies. The types of failure include debonding at the composite-tooth interface, delamination of the veneering material from the FRC substructure and fracture of the pontic. The design of the FRC substructure, i.e. the position and orientation of the fibres, will affect the fracture resistance of the FPD. The purpose of this study was to find an optimal arrangement of the FRC substructure, by means of structural optimization, which could minimize the failure-initiating stresses in a three-unit FPD. A structural optimization method mimicking biological adaptive growth was developed for orthotropic materials such as FRC and incorporated into the finite element (FE) program ABAQUS. Using the program, optimization of the fibre positions and directions in a three-unit FPD was carried out, the aim being to align the fibre directions with those of the maximum principal stresses. The optimized design was then modeled and analyzed to verify the improvements in mechanical performance of the FPD. Results obtained from the optimization suggested that the fibres should be placed at the bottom of the pontic, forming a U-shape substructure that extended into the connectors linking the teeth and the pontic. FE analyses of the optimized design indicated stress reduction in both the veneering composite and at the interface between the veneer and the FRC substructure. The optimized design obtained using FE-based structural optimization can potentially improve the fracture resistance of FPDs by reducing some of the failure-initiating stresses. Optimization methods can therefore be a useful tool to provide sound scientific guidelines for the design of FRC substructures in FPDs.

  8. A comparison between the effect of zirconia-coated FRC and glass fiber posts on the fracture resistance of endodontically treated teeth

    Directory of Open Access Journals (Sweden)

    Ezatollah Jalalian

    2014-04-01

    Full Text Available   Background and Aims : The root fracture resistance of endodontically treated teeth depends on the types of posts. The aim of this study was to compare the effect of two types of bonded non-metallic posts with different elasticity modulus on the fracture resistance of endodontically treated teeth under compressive loads.   Materials and Methods: In this in vitro experimental study, 20 fresh extracted mandibular premolars were selected and sectioned adjacent to the CEJ and then were endodontically treated. The specimens were randomly divided into two groups (n=10. After post space preparations, the fiber RTD Light posts (R.T.D, France and zirconia coated fiber posts (ICE light, Danville were cemented into the root canals. Composite resin (Lumiglass R.T.D, France cores were built up. Aluminium foil was used to mimic the PDL, and the specimens were embedded in acrylic resin and tested in a Universal Testing Machine. A compressive load was applied at a 90 degree angle until fracture at a crosshead speed of 1mm/min. Data were analyzed using one-way ANOVA and T test .   Results: The mean fracture resistance of R.T.D group was (1083.11 ± 156.74 (N and the mean of ICE light group was (865.18 ± 106.24 (N. The highest mean fracture resistance was observed in RTD fiberglass and a statistically significant difference was observed between the two groups (P<0.001.   Conclusion: FRC posts with zirconia coating due to unfavorable fractures of the teeth should be used with caution, and thus, fiber posts are preferred.

  9. Density, thickness and composition measurements of TiO{sub 2} -SiO{sub 2} thin films by coupling X-ray reflectometry, ellipsometry and electron probe microanalysis-X

    Energy Technology Data Exchange (ETDEWEB)

    Hodroj, A. [Laboratoire des Materiaux et du Genie Physique (UMR 5628 CNRS), Ecole Nationale Superieure de Physique de Grenoble, Institut National Polytechnique de Grenoble, Minatec, 3 parvis Louis Neel, BP 257, 38016 Grenoble Cedex 1 (France)]. E-mail: abbas.hodroj@inpg.fr; Roussel, H. [Laboratoire des Materiaux et du Genie Physique (UMR 5628 CNRS), Ecole Nationale Superieure de Physique de Grenoble, Institut National Polytechnique de Grenoble, Minatec, 3 parvis Louis Neel, BP 257, 38016 Grenoble Cedex 1 (France); Crisci, A. [Consortium des Moyens Technologiques Communs, Institut National Polytechnique de Grenoble, BP 75, 38402 St. Martin d' Heres (France); Robaut, F. [Consortium des Moyens Technologiques Communs, Institut National Polytechnique de Grenoble, BP 75, 38402 St. Martin d' Heres (France); Gottlieb, U. [Laboratoire des Materiaux et du Genie Physique (UMR 5628 CNRS), Ecole Nationale Superieure de Physique de Grenoble, Institut National Polytechnique de Grenoble, Minatec, 3 parvis Louis Neel, BP 257, 38016 Grenoble Cedex 1 (France); Deschanvres, J.L. [Laboratoire des Materiaux et du Genie Physique (UMR 5628 CNRS), Ecole Nationale Superieure de Physique de Grenoble, Institut National Polytechnique de Grenoble, Minatec, 3 parvis Louis Neel, BP 257, 38016 Grenoble Cedex 1 (France)

    2006-10-31

    Mixed TiO{sub 2} -SiO{sub 2} thin films were deposited by aerosol atmospheric CVD method by using di-acetoxi di-butoxi silane (DADBS) and Ti tetra-butoxide as precursors. By varying the deposition temperatures between 470 and 600 deg. C and the ratios between the Si and Ti precursors (Si/Ti) from 2 up to 16, films with different compositions and thicknesses were deposited. The coupled analysis of the results of different characterisation methods was used in order to determine the variation of the composition, the thickness and the density of the films. First EPMA measurements were performed at different acceleration voltages with a Cameca SX50 system. By analysing, with specific software, the evolution of the intensity ratio I {sub x}/I {sub std} versus the voltage, the composition and the mass thickness (product of density by the thickness) were determined. In order to measure independently the density, X-ray reflectometry experiments were performed. By analysing the value of the critical angle and the Kiessig fringes, the density and the thickness of the layers were determined. The refractive index and the thickness of the films were also measured by ellipsometry. By assuming a linear interpolation between the index value of the pure SiO{sub 2} and TiO{sub 2} films, the film composition was deduced from the refractive index value. XPS measurements were also performed in order to obtain an independent value of the composition. A good agreement between the ways to measure the density is obtained.

  10. Seasonal changes in isoform composition of giant proteins of thick and thin filaments and titin (connectin) phosphorylation level in striated muscles of bears (Ursidae, Mammalia).

    Science.gov (United States)

    Salmov, N N; Vikhlyantsev, I M; Ulanova, A D; Gritsyna, Yu V; Bobylev, A G; Saveljev, A P; Makariushchenko, V V; Maksudov, G Yu; Podlubnaya, Z A

    2015-03-01

    Seasonal changes in the isoform composition of thick and thin filament proteins (titin, myosin heavy chains (MyHCs), nebulin), as well as in the phosphorylation level of titin in striated muscles of brown bear (Ursus arctos) and hibernating Himalayan black bear (Ursus thibetanus ussuricus) were studied. We found that the changes that lead to skeletal muscle atrophy in bears during hibernation are not accompanied by a decrease in the content of nebulin and intact titin-1 (T1) isoforms. However, a decrease (2.1-3.4-fold) in the content of T2 fragments of titin was observed in bear skeletal muscles (m. gastrocnemius, m. longissimus dorsi, m. biceps) during hibernation. The content of the stiffer N2B titin isoform was observed to increase relative to the content of its more compliant N2BA isoform in the left ventricles of hibernating bears. At the same time, in spite of the absence of decrease in the total content of T1 in the myocardium of hibernating brown bear, the content of T2 fragments decreased ~1.6-fold. The level of titin phosphorylation only slightly increased in the cardiac muscle of hibernating brown bear. In the skeletal muscles of brown bear, the level of titin phosphorylation did not vary between seasons. However, changes in the composition of MyHCs aimed at increasing the content of slow (I) and decreasing the content of fast (IIa) isoforms of this protein during hibernation of brown bear were detected. Content of MyHCs I and IIa in the skeletal muscles of hibernating Himalayan black bear corresponded to that in the skeletal muscles of hibernating brown bear.

  11. Thickness-, Composition-, and Magnetic-Field-Dependent Complex Impedance Spectroscopy of Granular-Type-Barrier Co/Co-Al2O3/Co MTJs

    Science.gov (United States)

    Tuan, Nguyen Anh; Anh, Nguyen Tuan; Nga, Nguyen Tuyet; Tue, Nguyen Anh; Van Cuong, Giap

    2016-06-01

    The alternating-current (ac) electrical properties of granular-type-barrier magnetic tunnel junctions (GBMTJs) based on Co/Co x (Al2O3)1- x ( t)/Co trilayer structures have been studied using complex impedance spectroscopy (CIS). Their CIS characteristics were investigated in external magnetic fields varying from 0 kOe to 3 kOe as a function of Co composition x at 10 at.%, 25 at.%, and 35 at.%, with barrier layer thickness t of 20 nm to 90 nm. The influence of these factors on the behaviors of the ac impedance response of the GBMTJs was deeply investigated and attributed to the dielectric or conducting nature of the Co-Al2O3 barrier layer. The most remarkable typical phenomena observed in these behaviors, even appearing paradoxical, include lower impedance for thicker t for each given x, a declining trend of Z with increasing x, a clear decrease of Z with H, and especially a partition of Z into zones according to the H value. All these effects are analyzed and discussed to demonstrate that diffusion-type and mass-transfer-type phenomena can be inferred from processes such as spin tunneling and Coulomb or spin blockade in the Co-Al2O3 barrier layer.

  12. An overview of development and status of fiber-reinforced composites as dental and medical biomaterials.

    Science.gov (United States)

    Vallittu, Pekka K

    2018-01-01

    Fibr-reinforced composites (FRC) have been used successfully for decades in many fields of science and engineering applications. Benefits of FRCs relate to physical properties of FRCs and versatile production methods, which can be utilized. Conventional hand lamination of prefabricated FRC prepregs is utilized still most commonly in fabrication of dental FRC devices but CAD-CAM systems are to be come for use in certain production steps of dental constructions and medical FRC implants. Although metals, ceramics and particulate filler resin composites have successfully been used as dental and medical biomaterials for decades, devices made out of these materials do not meet all clinical requirements. Only little attention has been paid to FRCs as dental materials and majority of the research in dental field has been focusing on particulate filler resin composites and in medical biomaterial research to biodegradable polymers. This is paradoxical because FRCs can potentially resolve many of the problems related to traditional isotropic dental and medical materials. This overview reviews the rationale and status of using biostable glass FRC in applications from restorative and prosthetic dentistry to cranial surgery. The overview highlights also the critical material based factors and clinical requirement for the succesfull use of FRCs in dental reconstructions.

  13. Polymer matrix of fiber-reinforced composites: Changes in the semi-interpenetrating polymer network during the shelf life.

    Science.gov (United States)

    Khan, Aftab A; Al-Kheraif, Abdulaziz A; Al-Shehri, Abdullah M; Säilynoja, Eija; Vallittu, Pekka K

    2018-02-01

    This laboratory study was aimed to characterize semi-interpenetrating polymer network (semi-IPN) of fiber-reinforced composite (FRC) prepregs that had been stored for up to two years before curing. Resin impregnated prepregs of everStick C&B (StickTech-GC, Turku, Finland) glass FRC were stored at 4°C for various lengths of time, i.e., two-weeks, 6-months and 2-years. Five samples from each time group were prepared with a light initiated free radical polymerization method, which were embedded to its long axis in self-curing acrylic. The nanoindentation readings on the top surface toward the core of the sample were made for five test groups, which were named as "stage 1-5". To evaluate the nanohardness and modulus of elasticity of the polymer matrix, a total of 4 slices (100µm each) were cut from stage 1 to stage 5. Differences in nanohardness values were evaluated with analysis of variance (ANOVA), and regression model was used to develop contributing effect of the material's different stages to the total variability in the nanomechanical properties. Additional chemical and thermal characterization of the polymer matrix structure of FRC was carried out. It was hypothesized that time of storage may have an influence on the semi-IPN polymer structure of the cured FRC. The two-way ANOVA test revealed that the storage time had no significant effect on the nanohardness of FRC (p = 0.374). However, a highly significant difference in nanohardness values was observed between the different stages of FRC (Pprepregs might be due to phase-segregation of components of semi-IPN structure of FRC prepregs before their use. This may have an influence to the surface bonding properties of the cured FRC. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Effect of implant design and bioactive glass coating on biomechanical properties of fiber-reinforced composite implants.

    Science.gov (United States)

    Ballo, Ahmed M; Akca, Eralp; Ozen, Tuncer; Moritz, Niko; Lassila, Lippo; Vallittu, Pekka; Närhi, Timo

    2014-08-01

    This study aimed to evaluate the influence of implant design and bioactive glass (BAG) coating on the response of bone to fiber-reinforced composite (FRC) implants. Three different FRC implant types were manufactured for the study: non-threaded implants with a BAG coating; threaded implants with a BAG coating; and threaded implants with a grit-blasted surface. Thirty-six implants (six implants for each group per time point) were installed in the tibiae of six pigs. After an implantation period of 4 and 12 wk, the implants were retrieved and prepared for micro-computed tomography (micro-CT), push-out testing, and scanning electron microscopy analysis. Micro-CT demonstrated that the screw-threads and implant structure remained undamaged during the installation. The threaded FRC/BAG implants had the highest bone volume after 12 wk of implantation. The push-out strengths of the threaded FRC/BAG implants after 4 and 12 wk (463°N and 676°N, respectively) were significantly higher than those of the threaded FRC implants (416°N and 549°N, respectively) and the nonthreaded FRC/BAG implants (219°N and 430°N, respectively). Statistically significant correlation was found between bone volume and push-out strength values. This study showed that osseointegrated FRC implants can withstand the static loading up to failure without fracture, and that the addition of BAG significantly improves the push-out strength of FRC implants. © 2014 Eur J Oral Sci.

  15. Static and dynamic through thickness lamina properties of thick laminates

    NARCIS (Netherlands)

    Lahuerta, F.; Nijssen, R.P.L.; Van der Meer, F.P.; Sluys, L.J.

    2015-01-01

    Thick laminates are increasingly present in large composites structures such as wind turbine blades. Different factors are suspected to be involved in the decreased static and dynamic performance of thick laminates. These include the effect of self-heating, the scaling effect, and the manufacturing

  16. Fiber-reinforced Composite Resin Prosthesis to Restore Missing ...

    African Journals Online (AJOL)

    A fiber-reinforced composite inlay-onlay FPD was used for a single posterior tooth replacement in a patient refusing implant for psychological reasons. The FRC-FPD was made of pre-impregnated E-glass fibers (everStick, StickTeck, Turku, Finland) embedded in a resin matrix (Stick Resin, StickTeck, Turku, Finland).

  17. Fracture resistance of reattached incisor fragments with mini fibre-reinforced composite anchors.

    NARCIS (Netherlands)

    Fennis, W.M.M.; Kreulen, C.M.; Wolke, J.G.C.; Fokkinga, W.A.; Machado, C.; Creugers, N.H.J.

    2009-01-01

    OBJECTIVES: Fractured coronal fragments of incisors can be adhered to the remaining tooth with resin composite, but are prone to failure. This study explores whether mini fibre-reinforced composite (FRC) anchors increase fracture resistance of reattached fragments. METHODS: Forty-five extracted

  18. Explicit modeling the progressive interface damage in fibrous composite: Analytical vs. numerical approach

    DEFF Research Database (Denmark)

    Kushch, V.I.; Shmegera, S.V.; Mishnaevsky, Leon

    2011-01-01

    of the multiple inclusion problem by means of complex potentials. The second, finite element model of FRC is based on the cohesive zone model of interface. Simulation of progressive debonding in FRC using the many-fiber models of composite has been performed. The advantageous features and applicability areas...... of both models are discussed. It has been shown that the developed models provide detailed analysis of the progressive debonding phenomena including the interface crack cluster formation, overall stiffness reduction and induced anisotropy of the effective elastic moduli of composite....

  19. Post-impact fatigue of cross-plied, through-the-thickness reinforced carbon/epoxy composites. M.S. Thesis - Clemson Univ.

    Science.gov (United States)

    Serdinak, Thomas E.

    1994-01-01

    An experimental investigation of the post-impact fatigue response of integrally woven carbon/epoxy composites was conducted. Five different through-the-thickness (TTT) reinforcing fibers were used in an experimental textile process that produced an integrally woven (0/90/0/90/0/90/0/90/0)(sub T) ply layup with 21K AS4 carbon tow fiber. The resin was Hercules 3501-6, and the five TTT reinforcing fibers were Kevlar, Toray carbon, AS4 carbon, glass, and IM6 carbon. The purpose of this investigation was to study the post-impact fatigue response of these material systems and to identify the optimum TTT fiber. Samples were impacted with one half inch diameter aluminum balls with an average velocity of 543 ft/sec. Post-impact static compression and constant amplitude tension-compression fatigue tests were conducted. Fatigue tests were conducted with a loading ratio of R=-5, and frequency of 4 Hz. Damage growth was monitored using x-radiographic and sectioning techniques and by examining the stress-strain response (across the impact site) throughout the fatigue tests. The static compressive stress versus far-field strain response was nearly linear for all material groups. All the samples had a transverse shear failure mode. The average compressive modulus (from far-field strain) was about 10 Msi. The average post-impact static compressive strength was about 35.5 Ksi. The IM6 carbon sample had a strength of over 40 Ksi, more than 16 percent stronger than average. There was considerable scatter in the S-N data. However, the IM6 carbon samples clearly had the best fatigue response. The response of the other materials, while worse than IM6 carbon, could not be ranked definitively. The initial damage zones caused by the impact loading and damage growth from fatigue loading were similar for all five TTT reinforcing materials. The initial damage zones were circular and consisted of delaminations, matrix cracks and ply cracks. Post-impact fatigue loading caused delamination growth

  20. Immediate Repair Bond Strength of Fiber-reinforced Composite after Saliva or Water Contamination.

    Science.gov (United States)

    Bijelic-Donova, Jasmina; Flett, Andrew; Lassila, Lippo V J; Vallittu, Pekka K

    2018-05-31

    This in vitro study aimed to evaluate the shear bond strength (SBS) of particulate filler composite (PFC) to saliva- or water-contaminated fiber-reinforced composite (FRC). One type of FRC substrate with semi-interpenetrating polymer matrix (semi-IPN) (everStick C&B) was used in this investigation. A microhybrid PFC (Filtek Z250) substrate served as control. Freshly cured PFC and FRC substrates were first subjected to different contamination and surface cleaning treatments, then the microhybrid PFC restorative material (Filtek Z250) was built up on the substrates in 2-mm increments and light cured. Uncontaminated and saliva- or water-contaminated substrate surfaces were either left untreated or were cleaned via phosphoric acid etching or water spray accompanied with or without adhesive composite application prior applying the adherent PFC material. SBS was evaluated after thermocycling the specimens (6000 cycles, 5°C and 55°C). Three-way ANOVA showed that both the surface contamination and the surface treatment signficantly affected the bond strength (p contamination reduced the SBS more than did the water contamination. SBS loss after saliva contamination was 73.7% and 31.3% for PFC and FRC, respectively. After water contamination, SBS loss was 17.2% and 13.3% for PFC and FRC, respectively. The type of surface treatment was significant for PFC (p contamination of freshly cured PFC or semi-IPN FRC, surfaces should be re-prepared via phosphoric acid etching, water cleaning, drying, and application of adhesive composite in order to recover optimal bond strength.

  1. Multi-Scale CNT-Based Reinforcing Polymer Matrix Composites for Lightweight Structures

    Science.gov (United States)

    Eberly, Daniel; Ou, Runqing; Karcz, Adam; Skandan, Ganesh; Mather, Patrick; Rodriguez, Erika

    2013-01-01

    Reinforcing critical areas in carbon polymer matrix composites (PMCs), also known as fiber reinforced composites (FRCs), is advantageous for structural durability. Since carbon nanotubes (CNTs) have extremely high tensile strength, they can be used as a functional additive to enhance the mechanical properties of FRCs. However, CNTs are not readily dispersible in the polymer matrix, which leads to lower than theoretically predicted improvement in mechanical, thermal, and electrical properties of CNT composites. The inability to align CNTs in a polymer matrix is also a known issue. The feasibility of incorporating aligned CNTs into an FRC was demonstrated using a novel, yet commercially viable nanofiber approach, termed NRMs (nanofiber-reinforcing mats). The NRM concept of reinforcement allows for a convenient and safe means of incorporating CNTs into FRC structural components specifically where they are needed during the fabrication process. NRMs, fabricated through a novel and scalable process, were incorporated into FRC test panels using layup and vacuum bagging techniques, where alternating layers of the NRM and carbon prepreg were used to form the reinforced FRC structure. Control FRC test panel coupons were also fabricated in the same manner, but comprised of only carbon prepreg. The FRC coupons were machined to size and tested for flexural, tensile, and compression properties. This effort demonstrated that FRC structures can be fabricated using the NRM concept, with an increased average load at break during flexural testing versus that of the control. The NASA applications for the developed technologies are for lightweight structures for in-space and launch vehicles. In addition, the developed technologies would find use in NASA aerospace applications such as rockets, aircraft, aircraft/spacecraft propulsion systems, and supporting facilities. The reinforcing aspect of the technology will allow for more efficient joining of fiber composite parts, thus offering

  2. Preparation and characterisation of poly p-phenylene-2,6-benzobisoxazole fibre-reinforced resin matrix composite for endodontic post material: a preliminary study.

    Science.gov (United States)

    Hu, Chen; Wang, Feng; Yang, Huiyong; Ai, Jun; Wang, Linlin; Jing, Dongdong; Shao, Longquan; Zhou, Xingui

    2014-12-01

    Currently used fibre-reinforced composite (FRC) intracanal posts possess low flexural strength which usually causes post fracture when restoring teeth with extensive loss. To improve the flexural strength of FRC, we aimed to apply a high-performance fibre, poly p-phenylene-2, 6-benzobisoxazole (PBO), to FRCs to develop a new intracanal post material. To improve the interfacial adhesion strength, the PBO fibre was treated with coupling agent (Z-6040), argon plasma, or a combination of above two methods. The effects of the surface modifications on PBO fibre were characterised by determining the single fibre tensile strength and interfacial shear strength (IFSS). The mechanical properties of PBO FRCs were characterised by flexural strength and flexural modulus. The cytotoxicity of PBO FRC was evaluated by the MTT assay. Fibres treated with a combination of Z-6040 and argon plasma possessed a significantly higher IFSS than untreated fibres. Fibre treated with the combination of Z-6040-argon-plasma FRC had the best flexural strength (531.51 ± 26.43MPa) among all treated fibre FRCs and had sufficient flexural strength and appropriate flexural moduli to be used as intracanal post material. Furthermore, an in vitro cytotoxicity assay confirmed that PBO FRCs possessed an acceptable level of cytotoxicity. In summary, our study verified the feasibility of using PBO FRC composites as new intracanal post material. Although the mechanical property of PBO FRC still has room for improvement, our study provides a new avenue for intracanal post material development in the future. To our knowledge, this is the first study to verify the feasibility of using PBO FRC composites as new intracanal post material. Our study provided a new option for intracanal post material development. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Core–shell structured FeSiAl/SiO{sub 2} particles and Fe{sub 3}Si/Al{sub 2}O{sub 3} soft magnetic composite cores with tunable insulating layer thicknesses

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Xi’an, E-mail: groupfxa@163.com [The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Wang, Jian, E-mail: snove418562@163.com [The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Wu, Zhaoyang, E-mail: wustwuzhaoyang@163.com [The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Li, Guangqiang, E-mail: ligq-wust@mail.wust.edu.cn [The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China)

    2015-11-15

    Graphical abstract: - Highlights: • FeSiAl/SiO{sub 2} core–shell particles and Fe{sub 3}Si/Al{sub 2}O{sub 3} composite cores were prepared. • SiO{sub 2} surrounding FeSiAl were replaced by Al{sub 2}O{sub 3} during sintering process. • Fe{sub 3}Si particles were separated by Al{sub 2}O{sub 3} with tunable thickness in composite cores. • Fe{sub 3}Si/Al{sub 2}O{sub 3} had lower core loss and better frequency stability than FeSiAl core. • The insulating layer between ferromagnetic particles can reduce core loss. - Abstract: FeSiAl/SiO{sub 2} core–shell particles and Fe{sub 3}Si/Al{sub 2}O{sub 3} composite cores with tunable insulating layer thicknesses have been synthesized via a modified Stöber method combined with following high temperature sintering process. Most of the conductive FeSiAl particles could be coated by insulating SiO{sub 2} using the modified Stöber method. During the sintering process, the reaction 4Al + 3SiO{sub 2} ≣ 2α-Al{sub 2}O{sub 3} + 3Si took place and the new Fe{sub 3}Si/Al{sub 2}O{sub 3} composite was formed. The Fe{sub 3}Si/Al{sub 2}O{sub 3} composite cores displayed more excellent soft magnetic properties, better frequency stability at high frequencies, much higher resistivity and lower core loss than the raw FeSiAl core. Based on this, several types of FeSiAl/SiO{sub 2} particles and Fe{sub 3}Si/Al{sub 2}O{sub 3} composite cores with tunable insulating layer thicknesses were selectively prepared by simply varying TEOS contents. The thickness of Al{sub 2}O{sub 3} insulating layer and resistivity of Fe{sub 3}Si/Al{sub 2}O{sub 3} composite cores increased with increasing the TEOS contents, while the permeability and core loss changed in the opposite direction.

  4. Dual beam x-ray thickness gauge

    International Nuclear Information System (INIS)

    Allport, J.J.

    1977-01-01

    The apparatus and method for continuous measurement of thickness of a sheet at a rolling mill or the like without contacting the sheet are described. A system directing radiation through the sheet in two energy bands and providing a measure of change in composition of the material as it passes the thickness gauging station is included. A system providing for changing the absorption coefficient of the material in the thickness measurement as a function of the change in composition so that the measured thickness is substantially independent of variations in composition is described

  5. Composites

    International Nuclear Information System (INIS)

    Kasen, M.B.

    1983-01-01

    This chapter discusses the roles of composite laminates and aggregates in cryogenic technology. Filamentary-reinforced composites are emphasized because they are the most widely used composite materials. Topics considered include composite systems and terminology, design and fabrication, composite failure, high-pressure reinforced plastic laminates, low-pressure reinforced plastics, reinforced metals, selectively reinforced structures, the effect of cryogenic temperatures, woven-fabric and random-mat composites, uniaxial fiber-reinforced composites, composite joints in cryogenic structures, joining techniques at room temperature, radiation effects, testing laminates at cryogenic temperatures, static and cyclic tensile testing, static and cyclic compression testing, interlaminar shear testing, secondary property tests, and concrete aggregates. It is suggested that cryogenic composite technology would benefit from the development of a fracture mechanics model for predicting the fitness-for-purpose of polymer-matrix composite structures

  6. Micromechanical modeling of strength and damage of fiber reinforced composites

    Energy Technology Data Exchange (ETDEWEB)

    Mishnaevsky, L. Jr.; Broendsted, P.

    2007-03-15

    The report for the first year of the EU UpWind project includes three parts: overview of concepts and methods of modelling of mechanical behavior, deformation and damage of unidirectional fiber reinforced composites, development of computational tools for the automatic generation of 3D micromechanical models of fiber reinforced composites, and micromechanical modelling of damage in FRC, and phenomenological analysis of the effect of frequency of cyclic loading on the lifetime and damage evolution in materials. (au)

  7. Comparison of Film Thickness of Two Commercial Brands of Glass lonomer Cement and One Dual-cured Composite: An in vitro Study.

    Science.gov (United States)

    Khajuria, Rajat R; Singh, Rishav; Barua, Pranamee; Hajira, Nausheen; Gupta, Naveen; Thakkar, Rohit R

    2017-08-01

    The present study is undertaken to examine the film thickness of three most commonly used luting cements and to determine their usage as a luting agent. This study was carried out strictly according to the guidelines of American Dental Association (ADS) specification no. 8. Two glass slabs of 5 cm in length and 2 cm in width were used. One glass slab was kept over the other glass slab and the space between the two glass slabs was measured using metallurgical microscope at the power of 10*. Two brands of glass ionomer cement (GIC) and one dual-cured resin cement were used in this study. The test cement is sandwiched between two glass slabs. A static load of 15 kg was applied using universal testing machine on the glass slabs for 1 hour and the space present between the two glass slabs was measured using metallurgical microscope at the power of 10*. Greatest film thickness was found in group III (Paracore) followed by group II (micron) and lowest in group I (GC luting and lining cement). All the tested samples can be used for luting purposes. Greatest film thickness was observed in Paracore followed by micron and lowest in GC luting and lining cement. This suggests that the 25 to 27°C is ideal for mixing of the cement when used for luting consistency. The cement with film thickness more than 30 urn should never be used for luting purposes. The dentist should choose the luting cement with utmost care noting the film thickness and bond strength of the cement. The cement with low exothermic heat production and good bond strength should be encouraged.

  8. In vitro fracture resistance of fiber reinforced cusp-replacing composite restorations.

    NARCIS (Netherlands)

    Fennis, W.M.M.; Tezvergil, A.; Kuijs, R.H.; Lassila, L.V.; Kreulen, C.M.; Creugers, N.H.J.; Vallittu, P.K.

    2005-01-01

    OBJECTIVES: To assess the fracture resistance and failure mode of fiber reinforced composite (FRC) cusp-replacing restorations in premolars. METHODS: Forty-five extracted sound upper premolars were randomly divided into three groups. Identical MOD cavities with simulated buccal cusp fracture and

  9. Adhesive Properties of Bonded Orthodontic Retainers to Enamel : Stainless Steel Wire vs Fiber-reinforced Composites

    NARCIS (Netherlands)

    Foek, Dave Lie Sam; Krebs, Eliza; Sandham, John; Ozcan, Mutlu

    2009-01-01

    Purpose: The objectives of this study were to compare the bond strength of a stainless steel orthodontic wire vs various fiber-reinforced composites (FRC) used as orthodontic retainers on enamel, analyze the failure types after debonding, and investigate the influence of different application

  10. Light energy transmission and Vickers hardness ratio of bulk-fill resin based composites at different thicknesses cured by a dual-wave or a single-wave light curing unit.

    Science.gov (United States)

    Santini, Ario; Naaman, Reem Khalil; Aldossary, Mohammed Saeed

    2017-04-01

    To quantify light energy transmission through two bulk-fill resin-based composites and to measure the top to bottom surface Vickers hardness ratio (VHratio) of samples of various incremental thicknesses, using either a single-wave or dual-wave light curing unit (LCU). Tetric EvoCeram Bulk Fill (TECBF) and SonicFill (SF) were studied. Using MARC-RC, the irradiance delivered to the top surface of the samples 2, 3, 4 and 5 mm thick (n= 5 for each thickness) was adjusted to 800 mW/cm2 for 20 seconds (16 J/cm2) using either a single-wave, Bluephase or a dual-wave, Bluephase G2 LCUs. Light energy transmission through to the bottom surface of the specimens was measured at real time using MARC-RC. The Vickers hardness (VH) was determined using Vickers micro hardness tester and the VHratio was calculated. Data were analyzed using a general linear model in Minitab 16; α= 0.05. TECBF was more translucent than SF (Pwave Bluephase G2). SF showed significantly higher VH ratio than TECBF at all different thickness levels (P 0.05). TECBF showed significantly greater VH ratio when cured with the single-wave Bluephase than when using the dual-wave Bluephase G2 (Penergy through to the bottom surface and the VHratio are material dependent. Although TECBF is more translucent than SF, it showed lower VHratio compared to SF when cured with dual-wave Bluephase G2.

  11. Composition

    DEFF Research Database (Denmark)

    Bergstrøm-Nielsen, Carl

    2011-01-01

    Strategies are open compositions to be realised by improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound files will in some cases only provide a few minutes' sample. Please DOWNLOAD them to hear them in full...

  12. Composition

    DEFF Research Database (Denmark)

    2014-01-01

    Memory Pieces are open compositions to be realised solo by an improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound files will in some cases only provide a few minutes' sample. Please DOWNLOAD them to hear them...

  13. The influence of thermal stresses on the phase composition of 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 thick films

    Science.gov (United States)

    Uršič, Hana; Zarnik, Marina Santo; Tellier, Jenny; Hrovat, Marko; Holc, Janez; Kosec, Marija

    2011-01-01

    The influence of thermal stresses versus the phase composition for 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 (0.65PMN-0.35PT) thick films is being reported. The thermal residual stresses in the films have been calculated using the finite-element method. It has been observed that in 0.65PMN-0.35PT films a compressive stress enhances the thermodynamic stability of the tetragonal phase with the space group P4mm.

  14. Influence of retainer design on two-unit cantilever resin-bonded glass fiber reinforced composite fixed dental prostheses: an in vitro and finite element analysis study.

    Science.gov (United States)

    Keulemans, Filip; De Jager, Niek; Kleverlaan, Cornelis J; Feilzer, Albert J

    2008-10-01

    The aim of this study was to evaluate in vitro the influence of retainer design on the strength of two-unit cantilever resin-bonded glass fiber-reinforced composite (FRC) fixed dental prostheses (FDP). Four retainer designs were tested: a proximal box, a step-box, a dual wing, and a step-box-wing. Of each design on 8 human mandibular molars, FRC-FDPs of a premolar size were produced. The FRC framework was made of resin impregnated unidirectional glass fibers (Estenia C&B EG Fiber, Kuraray) and veneered with hybrid resin composite (Estenia C&B, Kuraray). Panavia F 2.0 (Kuraray) was used as resin luting cement. FRC-FDPs were loaded to failure in a universal testing machine. One-way ANOVA and Tukey's post-hoc test were used to evaluate the data. The four designs were analyzed with finite element analysis (FEA) to reveal the stress distribution within the tooth/restoration complex. Significantly lower fracture strengths were observed with inlay-retained FDPs (proximal box: 300 +/- 65 N; step-box: 309 +/- 37 N) compared to wing-retained FDPs (p optimal design for replacement of a single premolar by means of a two-unit cantilever FRC-FDPs.

  15. Novel imaging techniques, integrated with mineralogical, geochemical and microbiological characterizations to determine the biogeochemical controls on technetium mobility in FRC sediments. Final report

    International Nuclear Information System (INIS)

    Lloyd, Jonathan R.

    2009-01-01

    The objective of this research program was to take a highly multidisciplinary approach to define the biogeochemical factors that control technetium (Tc) mobility in FRC sediments. The aim was to use batch and column studies to probe the biogeochemical conditions that control the mobility of Tc at the FRC. Background sediment samples from Area 2 (pH 6.5, low nitrate, low 99 Tc) and Area 3 (pH 3.5, high nitrate, relatively high 99 Tc) of the FRC were selected (http://www.esd.ornl.gov/nabirfrc). For the batch experiments, sediments were mixed with simulated groundwater, modeled on chemical constituents of FRC waters and supplemented with 99 Tc(VII), both with and without added electron donor (acetate). The solubility of the Tc was monitored, alongside other biogeochemical markers (nitrate, nitrite, Fe(II), sulfate, acetate, pH, Eh) as the 'microcosms' aged. At key points, the microbial communities were also profiled using both cultivation-dependent and molecular techniques, and results correlated with the geochemical conditions in the sediments. The mineral phases present in the sediments were also characterized, and the solid phase associations of the Tc determined using sequential extraction and synchrotron techniques. In addition to the batch sediment experiments, where discrete microbial communities with the potential to reduce and precipitate 99 Tc will be separated in time, we also developed column experiments where biogeochemical processes were spatially separated. Experiments were conducted both with and without amendments proposed to stimulate radionuclide immobilization (e.g. the addition of acetate as an electron donor for metal reduction), and were also planned with and without competing anions at high concentration (e.g. nitrate, with columns containing Area 3 sediments). When the columns had stabilized, as determined by chemical analysis of the effluents, we used a spike of the short-lived gamma emitter 99m Tc (50-200 MBq; half life 6 hours) and its

  16. Novel imaging techniques, integrated with mineralogical, geochemical and microbiological characterizations to determine the biogeochemical controls on technetium mobility in FRC sediments

    Energy Technology Data Exchange (ETDEWEB)

    Jonathan R. Lloyd

    2009-02-03

    The objective of this research program was to take a highly multidisciplinary approach to define the biogeochemical factors that control technetium (Tc) mobility in FRC sediments. The aim was to use batch and column studies to probe the biogeochemical conditions that control the mobility of Tc at the FRC. Background sediment samples from Area 2 (pH 6.5, low nitrate, low {sup 99}Tc) and Area 3 (pH 3.5, high nitrate, relatively high {sup 99}Tc) of the FRC were selected (http://www.esd.ornl.gov/nabirfrc). For the batch experiments, sediments were mixed with simulated groundwater, modeled on chemical constituents of FRC waters and supplemented with {sup 99}Tc(VII), both with and without added electron donor (acetate). The solubility of the Tc was monitored, alongside other biogeochemical markers (nitrate, nitrite, Fe(II), sulfate, acetate, pH, Eh) as the 'microcosms' aged. At key points, the microbial communities were also profiled using both cultivation-dependent and molecular techniques, and results correlated with the geochemical conditions in the sediments. The mineral phases present in the sediments were also characterized, and the solid phase associations of the Tc determined using sequential extraction and synchrotron techniques. In addition to the batch sediment experiments, where discrete microbial communities with the potential to reduce and precipitate {sup 99}Tc will be separated in time, we also developed column experiments where biogeochemical processes were spatially separated. Experiments were conducted both with and without amendments proposed to stimulate radionuclide immobilization (e.g. the addition of acetate as an electron donor for metal reduction), and were also planned with and without competing anions at high concentration (e.g. nitrate, with columns containing Area 3 sediments). When the columns had stabilized, as determined by chemical analysis of the effluents, we used a spike of the short-lived gamma emitter {sup 99m}Tc (50

  17. The bond of different post materials to a resin composite cement and a resin composite core material.

    Science.gov (United States)

    Stewardson, D; Shortall, A; Marquis, P

    2012-01-01

    To investigate the bond of endodontic post materials, with and without grit blasting, to a resin composite cement and a core material using push-out bond strength tests. Fiber-reinforced composite (FRC) posts containing carbon (C) or glass (A) fiber and a steel (S) post were cemented into cylinders of polymerized restorative composite without surface treatment (as controls) and after grit blasting for 8, 16, and 32 seconds. Additional steel post samples were sputter-coated with gold before cementation to prevent chemical interaction with the cement. Cylindrical composite cores were bonded to other samples. After sectioning into discs, bond strengths were determined using push-out testing. Profilometry and electron microscopy were used to assess the effect of grit blasting on surface topography. Mean (standard deviation) bond strength values (MPa) for untreated posts to resin cement were 8.41 (2.80) for C, 9.61(1.88) for A, and 19.90 (3.61) for S. Prolonged grit blasting increased bond strength for FRC posts but produced only a minimal increase for S. After 32 seconds, mean values were 20.65 (4.91) for C, 20.41 (2.93) for A, and 22.97 (2.87) for S. Gold-coated steel samples produced the lowest bond strength value, 7.84 (1.40). Mean bond strengths for untreated posts bonded to composite cores were 6.19 (0.95) for C, 13.22 (1.61) for A, and 8.82 (1.18) for S, and after 32 seconds of grit blasting the values were 17.30 (2.02) for C, 26.47 (3.09) for A, and 20.61 (2.67) for S. FRC materials recorded higher roughness values before and after grit blasting than S. With prolonged grit blasting, roughness increased for A and C, but not for S. There was no evidence of significant bonding to untreated FRC posts, but significant bonding occurred between untreated steel posts and the resin cement. Increases in the roughness of FRC samples were material dependent and roughening significantly increased bond strength values (p<0.05). Surface roughening of the tested FRC posts is

  18. Effects of a finite melt on the thickness and composition of liquid phase epitaxial InGaAsP and InGaAs layers grown by the diffusion-limited step-cooling technique

    International Nuclear Information System (INIS)

    Cook, L.W.; Tashima, M.M.; Stillman, G.E.

    1980-01-01

    The thickness of InGaAsP (lambda/sub g/=1.15 μm) and InGaAs (lambda/sub g/=1.68 μm) liquid phase epitaxial layers grown on (100) InP substrates by the step-cooling technique has been measured as a function of growth time. (lambda/sub g/ is defined as the wavelength corresponding to the energy gap of the epitaxial layer.) For growth times much less than the shortest diffusion time tau/sub i/=l 2 /D/sub i/ of the melt constituents, where l is the melt height and D/sub i/ is the diffusivity of each component in the melt, the thickness is consistent with diffusion-limited theory, and the composition is constant. The time at which the growth rate deviates sharply from diffusion-limited theory and beyond which constant composition growth can no longer be maintained has been determined for the melt size used in our experiments and can be estimated for any melt size

  19. Composition

    DEFF Research Database (Denmark)

    Bergstrøm-Nielsen, Carl

    2014-01-01

    Cue Rondo is an open composition to be realised by improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound/video files will in some cases only provide a few minutes' sample, or the visuals will not appear at all....... Please DOWNLOAD them to see/hear them in full length! This work is licensed under a Creative Commons "by-nc" License. You may for non-commercial purposes use and distribute it, performance instructions as well as specially designated recordings, as long as the author is mentioned. Please see http...

  20. Influence of Nitinol wire surface treatment on oxide thickness and composition and its subsequent effect on corrosion resistance and nickel ion release.

    Science.gov (United States)

    Clarke, B; Carroll, W; Rochev, Y; Hynes, M; Bradley, D; Plumley, D

    2006-10-01

    Medical implants and devices are now used successfully in surgical procedures on a daily basis. Alloys of nickel and titanium, and in particular Nitinol are of special interest in the medical device industry, because of their shape memory and superelastic properties. The corrosion behavior of nitinol in the body is also of critical importance because of the known toxicological effects of nickel. The stability of a NiTi alloy in the physiological environment is dependant primarily on the properties of the mostly TiO(2) oxide layer that is present on the surface. For the present study, a range of nitinol wires have been prepared using different drawing processes and a range of surface preparation procedures. It is clear from the results obtained that the wire samples with very thick oxides also contain a high nickel content in the oxide layer. The untreated samples with the thicker oxides show the lowest pitting potential values and greater nickel release in both long and short-term experiments. It was also found that after long-term immersion tests breakdown potentials increased for samples that exhibited lower values initially. From these results it would appear that surface treatment is essential for the optimum bioperformance of nitinol. (c) 2006 Wiley Periodicals, Inc

  1. Composition profiles of several contaminated and cleaned surfaces of gold thick films on copper plates by Auger electron and secondary ion mass spectroscopies

    International Nuclear Information System (INIS)

    Komiya, S.; Mizuno, M.; Narusawa, T.; Maeda, H.; Yoshikawa, M.

    1974-01-01

    Preparation and evaluation of a clean Au film are investigated. Development of a preparation method for obtaining clean surface on a copper shell in the JFT-2a (DIVA) TOKAMAK toroidal vacuum chamber is the aim of the present work. Au films prepared by ion plating and vacuum evaporation have been analysed by a cylindrical mirror Auger electron analyser in combination with a quadrupole mass spectrometer during 2 keV Xe ion bombardment from a sputter ion gun over the whole range of thickness of several microns. Contaminants are found to segregate on the top surface and at the interface. To expose a clean Au surface by the ion bombardment, surface layers within 1000 A had to be removed from the surfaces contaminated by touching with either a naked hand or a nylon glove or covered by a small amount of Ti. Mutual diffusions across the interfaces are also analyzed as a function of the substrate temperature. A Nb sandwich layer inhibites effectively the mutual diffusion. (auth.)

  2. investigating water absorption and thickness swelling tendencies

    African Journals Online (AJOL)

    HOD

    In addition, G30E (30% reinforced glass fibre in the epoxy composite) was more resilient to moisture ... determine its suitability as per its water absorption and thickness ... lower thermal conductivity and low density as outlined in the Tables.

  3. Comparison between experimental stiffness changes and crack-thickness-dependent predictions on a 1D SiC-SiC composite

    Energy Technology Data Exchange (ETDEWEB)

    Morvan, J.-M. [Bordeaux-1 Univ., 33 - Talence (France). Lab. de Mecanique Physique; Baste, S. [Bordeaux-1 Univ., 33 - Talence (France). Lab. de Mecanique Physique

    1997-08-01

    The use of an ultrasonic device gives access to all the stiffness coefficients of materials. With the analytical expressions of the effective compliances of an anisotropic solid containing a crack system, it is possible to predict the compliances variation along a monotonous loading, the cracks being considered as slit cracks. When the crack opening displacement is taken into account, that leads to a good agreement between experimental and predicted compliances. The non linear behaviour of the 1D SiC-SiC composite is then simply described by the constitutive laws of both the various crack densities and cracks opening displacement functions. Furthermore, the comparison between experimental and predicted stiffnesses changes gives access to the schematic geometry of the cracks systems. (orig.)

  4. Preparation of Nd-Fe-B/α-Fe nano-composite thick-film magnets on various substrates using PLD with high laser energy density above 10 J/cm2

    Science.gov (United States)

    Nakano, M.; Kondo, H.; Yamashita, A.; Yanai, T.; Itakura, M.; Fukunaga, H.

    2018-05-01

    PLD (Pulsed Laser Deposition) method with high laser energy density (LED) above 10 J/cm2 followed by a flash annealing enabled us to obtain isotropic nano-composite thick-film magnets with (BH)max ≧ 80 kJ/m3 on polycrystalline Ta substrates. We also have demonstrated that a dispersed structure composed of α-Fe together with Nd2Fe14B phases with the average grain diameter of approximately 20 nm could be formed on the Ta substrates. In this study, we tried to enhance the (BH)max value by controlling the microstructure due to the usage of different metal based substrates with each high melting point such as Ti, Nb, and W. Although it was difficult to vary the microstructure and to improve the magnetic properties of the films deposited on the substrates, we confirmed that isotropic thick-film magnets with (BH)max ≧ 80 kJ/m3 based on the nano-dispersed α-Fe and Nd2Fe14B phases could be obtained on various metal substrates with totally different polycrystalline structure. On the other hand, the use of a glass substrate lead to the deterioration of magnetic properties of a film prepared using the same preparation process.

  5. The relationship between maternal body composition in early pregnancy and foetal mid-thigh soft-tissue thickness in the third trimester in a high-risk obstetric population.

    Science.gov (United States)

    Anglim, Breffini; Farah, Nadine; O'Connor, Clare; Daly, Niamh; Kennelly, Mairead M; Turner, Michael J

    2017-07-01

    Maternal obesity is an emerging challenge in contemporary obstetrics. To date there has been no study analysing the relationship between specific maternal body composition measurements and foetal soft-tissue measurements. The aim of this study was to determine whether measurement of maternal body composition at booking predicts foetal soft-tissue trajectories in the third trimester. We analysed the relationship between foetal thigh in the third trimester and both maternal BMI and body composition using the Tanita digital scales in the first trimester. Foetal subcutaneous thigh tissue measurements were obtained at intervals of 28, 32 and 36 weeks of gestation. A total of 160 women were identified. There was a direct correlation between MTST at 36 weeks and BMI (p = .002). There was a positive correlation between MTST at 36 weeks and leg fat mass (p = .13) and leg fat free mass (p = .013). There was a positive correlation between arm fat free mass and MTST at 36 weeks. We showed there is an association between maternal fat distribution and foetal subcutaneous thigh tissue measurements. MTST may be more useful in determining if a child is at risk of macrosomia. Impact statement Previous studies have suggested that maternal obesity programmes intrauterine foetal adiposity and growth. The aim of this study was to examine the relationship in a high-risk obstetric population between measurements of maternal body composition in early pregnancy and the assessment of foetal adiposity in the third trimester using serial ultrasound measurements of mid-thigh soft-tissue thickness. BMI is only a surrogate measurement of fat and does not measure fat distribution. Our study shows the distribution of both maternal fat and fat-free mass in early pregnancy may be positively associated with foetal soft-tissue measurements in the third trimester. Maternal arthropometric measurements other than BMI may help predict babies at risk of macrosomia and neonatal adiposity.

  6. Influence of thermal cycling on flexural properties of composites reinforced with unidirectional silica-glass fibers.

    Science.gov (United States)

    Meriç, Gökçe; Ruyter, I Eystein

    2008-08-01

    The purpose was to investigate the effect of water storage and thermal cycling on the flexural properties of differently sized unidirectional fiber-reinforced composites (FRCs) containing different quantities of fibers. The effect of fiber orientation on the thermal expansion of FRCs as well as how the stresses in the composites can be affected was considered. An experimental polymeric base material was reinforced with silica-glass fibers. The cleaned and silanized fibers were sized with either linear PBMA-size or crosslinked PMMA-size. For the determination of flexural properties and water uptake, specimens were processed with various quantities of differently sized unidirectional fibers. Water uptake of FRC was measured. Water immersed specimens were thermally cycled for 500 and 12,000 cycles (5 degrees C/55 degrees C). Flexural properties of "dry" and wet specimens with and without thermal cycling were determined by a three-point bending test. The linear coefficients of thermal expansion (LCTE) for FRC samples with different fiber orientations were determined using a thermomechanical analyzer. Water uptake of the FRC specimens increased with a decrease in fiber content of the FRC. Flexural properties of FRCs improved with increasing fiber content, whereas the flexural properties were not influenced significantly by water and thermal cycling. Fiber orientation had different effects on LCTE of FRCs. Unidirectional FRCs had two different LCTE in longitudinal and transverse directions whereas bidirectional FRCs had similar LCTE in two directions and a higher one in the third direction. The results of the study suggest that the surface-treated unidirectional silica-glass FRC can be used for long-term clinical applications in the oral cavity.

  7. The effect of silanated and impregnated fiber on the tensile strength of E-glass fiber reinforced composite retainer

    Directory of Open Access Journals (Sweden)

    Niswati Fathmah Rosyida

    2015-12-01

    Full Text Available Background: Fiber reinforced composite (FRC is can be used in dentistry as an orthodontic retainer. FRC  still has a limitations because of to  a weak bonding between fibers and matrix. Purpose: This research was aimed to evaluate the effect of silane as coupling agent and fiber impregnation on the tensile strength of E-glass FRC. Methods: The samples of this research were classified into two groups each of which consisted of three subgroups, namely the impregnated fiber group (original, 1x addition of silane, 2x addition of silane and the non-impregnated fiber group (original, 1x addition of silane, 2x addition of silane. The tensile strength was measured by a universal testing machine. The averages of the tensile strength in all groups then were compared by using Kruskal Wallis and Mann Whitney post hoc tests. Results: The averages of the tensile strength (MPa in the impregnated fiber group can be known as follow; original impregnated fiber (26.60±0.51, 1x addition of silane (43.38±4.42, and 2x addition of silane (36.22±7.23. The averages of tensile strength (MPa in the non-impregnated fiber group can also be known as follow; original non-impregnated fiber (29.38±1.08, 1x addition of silane (29.38±1.08, 2x addition of silane (12.48±2.37. Kruskal Wallis test showed that there was a significant difference between the impregnated fiber group and the non-impregnated fiber group (p<0.05. Based on the results of post hoc test, it is also known that the addition of silane in the impregnated fiber group had a significant effect on the increasing of the tensile strength of E-glass FRC (p<0.05, while the addition of silane in the non-impregnated fiber group had a significant effect on the decreasing of the tensile strength of E-glass FRC. Conclusion: It can be concluded that the addition of silane in the non-silanated fiber group can increase the tensile strength of E-glass FRC, but the addition of silane in the silanated fiber group can

  8. Two-year survival analysis of twisted wire fixed retainer versus spiral wire and fiber-reinforced composite retainers: a preliminary explorative single-blind randomized clinical trial.

    Science.gov (United States)

    Sobouti, Farhad; Rakhshan, Vahid; Saravi, Mahdi Gholamrezaei; Zamanian, Ali; Shariati, Mahsa

    2016-03-01

    Traditional retainers (both metal and fiber-reinforced composite [FRC]) have limitations, and a retainer made from more flexible ligature wires might be advantageous. We aimed to compare an experimental design with two traditional retainers. In this prospective preliminary clinical trial, 150 post-treatment patients were enrolled and randomly divided into three groups of 50 patients each to receive mandibular canine-to-canine retainers made of FRC, flexible spiral wire (FSW), and twisted wire (TW). The patients were monitored monthly. The time at which the first signs of breakage/debonding were detected was recorded. The success rates of the retainers were compared using chi-squared, Kaplan-Meier, and Cox proportional-hazard regression analyses (α = 0.05). In total, 42 patients in the FRC group, 41 in the FSW group, and 45 in the TW group completed the study. The 2-year failure rates were 35.7% in the FRC group, 26.8% in the FSW group, and 17.8% in the TW group. These rates differed insignificantly (chi-squared p = 0.167). According to the Kaplan-Meier analysis, failure occurred at 19.95 months in the FRC group, 21.37 months in the FSW group, and 22.36 months in the TW group. The differences between the survival rates in the three groups were not significant (Cox regression p = 0.146). Although the failure rate of the experimental retainer was two times lower than that of the FRC retainer, the difference was not statistically significant. The experimental TW retainer was successful, and larger studies are warranted to verify these results.

  9. Effects of core-to-dentin thickness ratio on the biaxial flexural strength, reliability, and fracture mode of bilayered materials of zirconia core (Y-TZP) and veneer indirect composite resins.

    Science.gov (United States)

    Su, Naichuan; Liao, Yunmao; Zhang, Hai; Yue, Li; Lu, Xiaowen; Shen, Jiefei; Wang, Hang

    2017-01-01

    Indirect composite resins (ICR) are promising alternatives as veneering materials for zirconia frameworks. The effects of core-to-dentin thickness ratio (C/Dtr) on the mechanical property of bilayered veneer ICR/yttria-tetragonal zirconia polycrystalline (Y-TZP) core disks have not been previously studied. The purpose of this in vitro study was to assess the effects of C/Dtr on the biaxial flexural strength, reliability, and fracture mode of bilayered veneer ICR/ Y-TZP core disks. A total of 180 bilayered 0.6-mm-thick composite resin disks in core material and C/Dtr of 2:1, 1:1, and 1:2 were tested with either core material placed up or placed down for piston-on-3-ball biaxial flexural strength. The mean biaxial flexural strength, Weibull modulus, and fracture mode were measured to evaluate the variation trend of the biaxial flexural strength, reliability, and fracture mode of the bilayered disks with various C/Dtr. One-way analysis of variance (ANOVA) and chi-square tests were used to evaluate the variation tendency of fracture mode with the C/Dtr or material placed down during testing (α=.05). Light microscopy was used to identify the fracture mode. The mean biaxial flexural strength and reliability improved with the increase in C/Dtr when specimens were tested with the core material either up and down, and depended on the materials that were placed down during testing. The rates of delamination, Hertzian cone cracks, subcritical radial cracks, and number of fracture fragments partially depended on the C/Dtr and the materials that were placed down during testing. The biaxial flexural strength, reliability, and fracture mode in bilayered structures of Y-TZP core and veneer ICR depend on both the C/Dtr and the material that was placed down during testing. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  10. Lead Thickness Measurements

    International Nuclear Information System (INIS)

    Rucinski, R.

    1998-01-01

    The preshower lead thickness applied to the outside of D-Zero's superconducting solenoid vacuum shell was measured at the time of application. This engineering documents those thickness measurements. The lead was ordered in sheets 0.09375-inch and 0.0625-inch thick. The tolerance on thickness was specified to be +/- 0.003-inch. The sheets all were within that thickness tolerance. The nomenclature for each sheet was designated 1T, 1B, 2T, 2B where the numeral designates it's location in the wrap and 'T' or 'B' is short for 'top' or 'bottom' half of the solenoid. Micrometer measurements were taken at six locations around the perimeter of each sheet. The width,length, and weight of each piece was then measured. Using an assumed pure lead density of 0.40974 lb/in 3 , an average sheet thickness was calculated and compared to the perimeter thickness measurements. In every case, the calculated average thickness was a few mils thinner than the perimeter measurements. The ratio was constant, 0.98. This discrepancy is likely due to the assumed pure lead density. It is not felt that the perimeter is thicker than the center regions. The data suggests that the physical thickness of the sheets is uniform to +/- 0.0015-inch.

  11. Bond slip and crack development in FRC and regular concrete specimens longitudinally reinforced with FRP or steel under tension loading

    DEFF Research Database (Denmark)

    Lárusson, Lárus Helgi; Fischer, Gregor

    2012-01-01

    tensile loading using high definition image analysis in two unique test setups. Two different types of cementitious materials, conventional concrete and highly ductile Engineered Cementitious Composite (ECC), and two types of reinforcement bars, regular steel and Glass Fiber Reinforcement Polymer (GFRP......The governing mechanism in the structural response of reinforced concrete members in tension is the interaction between structural reinforcement and the surrounding concrete matrix. The composite response and the mechanical integrations of reinforced cementitious members were investigated during......), were tested. It was found that the ductile ECC in contrast to regular brittle concrete decreases crack widths significantly which effectively results in decreased bond slip between the reinforcement and surrounding matrix. Furthermore the use of elastic GFRP in comparison to elastic/plastic steel...

  12. Education and "Thick" Epistemology

    Science.gov (United States)

    Kotzee, Ben

    2011-01-01

    In this essay Ben Kotzee addresses the implications of Bernard Williams's distinction between "thick" and "thin" concepts in ethics for epistemology and for education. Kotzee holds that, as in the case of ethics, one may distinguish between "thick" and "thin" concepts of epistemology and, further, that this distinction points to the importance of…

  13. Elastic interaction of partially debonded circular inclusions. II. Application to fibrous composite

    DEFF Research Database (Denmark)

    Kushch, V.I.; Shmegera, S.V.; Mishnaevsky, Leon

    2011-01-01

    have been solved to check an accuracy and numerical efficiency of the method. An effect of interface crack density on the effective elastic moduli of periodic and random structure FRC with interface damage has been evaluated. The developed approach provides a detailed analysis of the progressive...... debonding phenomenon including the interface cracks cluster formation, overall stiffness reduction and damage-induced anisotropy of the effective elastic moduli of composite....

  14. High-temperature mechanical and material design for SiC composites

    International Nuclear Information System (INIS)

    Ghoniem, N.M.

    1992-01-01

    Silicon Carbide (SiC) fiber reinforced composites (FRC's) are strong potential candidate structural and high heat flux materials for fusion reactors. During this past decade, they have been vigorously developed for use in aerospace and transportation applications. Recent fusion reactor systems studies, such as ARIES, have concluded that further development of SiC composites will result in significant safety, operational, and waste disposal advantages for fusion systems. A concise discussion of the main material and design issues related to the use of SiC FRC's as structural materials in future fusion systems is given in this paper. The status of material processing of SiC/SiC composites is first reviewed. The advantages and shortcomings of the leading processing technology, known as Chemical Vapor Infiltration are particularly highlighted. A brief outline of the design-relevant physical, mechanical, and radiation data base is then presented. SiC/SiC FRC's possess the advantage of increased apparent toughness under mechanical loading conditions. This increased toughness, however, is associated with the nucleation and propagation of small crack patterns in the structure. Design approaches and failure criteria under these conditions are discussed

  15. Fracture resistance of class IV fiber-reinforced composite resin restorations: An in vitro study

    Directory of Open Access Journals (Sweden)

    P S Praveen Kumar

    2017-01-01

    Full Text Available Objectives: The aim of this study was to evaluate fracture resistance of incisal edge fractures (Class IV restored with a Glass Fiber-reinforced Composite (FRC. Materials and Methods: Twenty-four extracted sound maxillary central incisors were randomly divided into two groups. Group I (control contained untreated teeth. Samples in experimental groups II were prepared by cutting the incisal (one-third part of the crown horizontally and was subjected to enamel preparations, then restored with a Glass FRC. Fracture resistance was evaluated as Newton's for samples tested in a Hounsfield universal testing machine. Failure modes were examined microscopically. Results: Mean peak failure load (Newton's observed in Glass Fiber-reinforced Nanocomposite was 863.50 ± 76.12. The experimental group showed similar types of failure modes with the majority occurring as cohesive and mixed type. 58% of the teeth in Glass FRC group fractured below the cementoenamel junction. Conclusion: Using Fiber reinforced composite substructure under conventional composites in Class IV restorations, the fracture resistance of the restored incisal edge could be increased.

  16. Ocean Sediment Thickness Contours

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Ocean sediment thickness contours in 200 meter intervals for water depths ranging from 0 - 18,000 meters. These contours were derived from a global sediment...

  17. Monitoring production target thickness

    International Nuclear Information System (INIS)

    Oothoudt, M.A.

    1993-01-01

    Pion and muon production targets at the Clinton P. Anderson Meson Physics Facility consist of rotating graphite wheels. The previous target thickness monitoring Procedure scanned the target across a reduced intensity beam to determine beam center. The fractional loss in current across the centered target gave a measure of target thickness. This procedure, however, required interruption of beam delivery to experiments and frequently indicated a different fractional loss than at normal beam currents. The new monitoring Procedure compares integrated ups and downs toroid current monitor readings. The current monitors are read once per minute and the integral of readings are logged once per eight-hour shift. Changes in the upstream to downstream fractional difference provide a nonintrusive continuous measurement of target thickness under nominal operational conditions. Target scans are now done only when new targets are installed or when unexplained changes in the current monitor data are observed

  18. Assessment of Tensile Bond Strength of Fiber-Reinforced Composite Resin to Enamel Using Two Types of Resin Cements and Three Surface Treatment Methods

    Directory of Open Access Journals (Sweden)

    Tahereh Ghaffari

    2015-10-01

    Full Text Available Background: Resin-bonded bridgework with a metal framework is one of the most conservative ways to replace a tooth with intact abutments. Visibility of metal substructure and debonding are the complications of these bridgeworks. Today, with the introduction of fiber-reinforced composite resins, it is possible to overcome these complications. The aim of this study was to evaluate the bond strength of fiber-reinforced composite resin materials (FRC to enamel. Methods: Seventy-two labial cross-sections were prepared from intact extracted teeth. Seventy-two rectangular samples of cured Vectris were prepared and their thickness was increased by adding Targis. The samples were divided into 3 groups for three different surface treatments: sandblasting, etching with 9% hydrofluoric acid, and roughening with a round tapered diamond bur. Each group was then divided into two subgroups for bonding to etched enamel by Enforce and Variolink II resin cements. Instron universal testing machine was used to apply a tensile force. The fracture force was recorded and the mode of failure was identified under a reflective microscope. Results: There were no significant differences in bond strength between the three surface treatment groups (P=0.53. The mean bond strength of Variolink II cement was greater than that of Enforce (P=0.04. There was no relationship between the failure modes (cohesive and adhesive and the two cement types. There was some association between surface treatment and failure mode. There were adhesive failures in sandblasted and diamond-roughened groups and the cohesive failure was dominant in the etched group. Conclusion: It is recommended that restorations made of fiber-reinforced composite resin be cemented with VariolinkII and surface-treated by hydrofluoric acid.   Keywords: Tensile bond strength; surface treatment methods; fiber-reinforced composite resin

  19. Translucency of dental ceramics with different thicknesses.

    Science.gov (United States)

    Wang, Fu; Takahashi, Hidekazu; Iwasaki, Naohiko

    2013-07-01

    The increased use of esthetic restorations requires an improved understanding of the translucent characteristics of ceramic materials. Ceramic translucency has been considered to be dependent on composition and thickness, but less information is available about the translucent characteristics of these materials, especially at different thicknesses. The purpose of this study was to investigate the relationship between translucency and the thickness of different dental ceramics. Six disk-shaped specimens of 8 glass ceramics (IPS e.max Press HO, MO, LT, HT, IPS e.max CAD LT, MO, AvanteZ Dentin, and Trans) and 5 specimens of 5 zirconia ceramics (Cercon Base, Zenotec Zr Bridge, Lava Standard, Lava Standard FS3, and Lava Plus High Translucency) were prepared following the manufacturers' instructions and ground to a predetermined thickness with a grinding machine. A spectrophotometer was used to measure the translucency parameters (TP) of the glass ceramics, which ranged from 2.0 to 0.6 mm, and of the zirconia ceramics, which ranged from 1.0 to 0.4 mm. The relationship between the thickness and TP of each material was evaluated using a regression analysis (α=.05). The TP values of the glass ceramics ranged from 2.2 to 25.3 and the zirconia ceramics from 5.5 to 15.1. There was an increase in the TP with a decrease in thickness, but the amount of change was material dependent. An exponential relationship with statistical significance (Pceramics and zirconia ceramics. The translucency of dental ceramics was significantly influenced by both material and thickness. The translucency of all materials increased exponentially as the thickness decreased. All of the zirconia ceramics evaluated in the present study showed some degree of translucency, which was less sensitive to thickness compared to that of the glass ceramics. Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  20. Coating thickness measurement

    International Nuclear Information System (INIS)

    1976-12-01

    The standard specifies measurements of the coating thickness, which make use of beta backscattering and/or x-ray fluorescence. For commonly used combinations of coating material and base material the appropriate measuring ranges and radionuclides to be used are given for continuous as well as for discontinuous measurements

  1. Coating thickness measuring device

    International Nuclear Information System (INIS)

    Joffe, B.B.; Sawyer, B.E.; Spongr, J.J.

    1984-01-01

    A device especially adapted for measuring the thickness of coatings on small, complexly-shaped parts, such as, for example, electronic connectors, electronic contacts, or the like. The device includes a source of beta radiation and a radiation detector whereby backscatter of the radiation from the coated part can be detected and the thickness of the coating ascertained. The radiation source and detector are positioned in overlying relationship to the coated part and a microscope is provided to accurately position the device with respect to the part. Means are provided to control the rate of descent of the radiation source and radiation detector from its suspended position to its operating position and the resulting impact it makes with the coated part to thereby promote uniformity of readings from operator to operator, and also to avoid excessive impact with the part, thereby improving accuracy of measurement and eliminating damage to the parts

  2. Stresses and strains in thick perforated orthotropic plates

    Science.gov (United States)

    A. Alshaya; John Hunt; R. Rowlands

    2016-01-01

    Stress and strain concentrations and in-plane and out-of-plane stress constraint factors associated with a circular hole in thick, loaded orthotropic composite plates are determined by three-dimensional finite element method. The plate has essentially infinite in-plane geometry but finite thickness. Results for Sitka Spruce wood are emphasized, although some for carbon...

  3. Thick melanoma in Tuscany.

    Science.gov (United States)

    Chiarugi, Alessandra; Nardini, Paolo; Borgognoni, Lorenzo; Brandani, Paola; Gerlini, Gianni; Rubegni, Pietro; Lamberti, Arianna; Salvini, Camilla; Lo Scocco, Giovanni; Cecchi, Roberto; Sirna, Riccardo; Lorenzi, Stefano; Gattai, Riccardo; Battistini, Silvio; Crocetti, Emanuele

    2017-03-14

    The epidemiologic trends of cutaneous melanoma are similar in several countries with a Western-type life style, where there is a progressive increasing incidence and a low but not decreasing mor- tality, or somewhere an increase too, especially in the older age groups. Also in Tuscany there is a steady rise in incidence with prevalence of in situ and invasive thin melanomas, with also an increase of thick melanomas. It is necessary to reduce the frequency of thick melanomas to reduce specific mortality. The objective of the current survey has been to compare, in the Tuscany population, by a case- case study, thin and thick melanoma cases, trying to find out those personal and tumour characteristics which may help to customize preventive interventions. RESULTS The results confirmed the age and the lower edu- cation level are associated with a later detection. The habit to perform skin self-examination is resulted protec- tive forward thick melanoma and also the diagnosis by a doctor. The elements emerging from the survey allow to hypothesize a group of subjects resulting at higher risk for a late diagnosis, aged over 50 and carrier of a fewer constitutional and environmental risk factors: few total and few atypical nevi, and lower sun exposure and burning. It is assumable that a part of people did not be reached from messages of prevention because does not recognize oneself in the categories of people at risk for skin cancers described in educational cam- paigns. If we want to obtain better results on diagnosis of skin melanoma we have to think a new strategy. At least to think over the educational messages discriminating people more at risk of incidence of melanoma from people more at risk to die from melanoma, and to renewed active involvement of the Gen- eral Practitioners .

  4. Thick brane solutions

    International Nuclear Information System (INIS)

    Dzhunushaliev, Vladimir; Minamitsuji, Masato; Folomeev, Vladimir

    2010-01-01

    This paper gives a comprehensive review on thick brane solutions and related topics. Such models have attracted much attention from many aspects since the birth of the brane world scenario. In many works, it has been usually assumed that a brane is an infinitely thin object; however, in more general situations, one can no longer assume this. It is also widely considered that more fundamental theories such as string theory would have a minimal length scale. Many multidimensional field theories coupled to gravitation have exact solutions of gravitating topological defects, which can represent our brane world. The inclusion of brane thickness can realize a variety of possible brane world models. Given our understanding, the known solutions can be classified into topologically non-trivial solutions and trivial ones. The former class contains solutions of a single scalar (domain walls), multi-scalar, gauge-Higgs (vortices), Weyl gravity and so on. As an example of the latter class, we consider solutions of two interacting scalar fields. Approaches to obtain cosmological equations in the thick brane world are reviewed. Solutions with spatially extended branes (S-branes) and those with an extra time-like direction are also discussed.

  5. Full reflector thickness and isolation thickness on neutron transport

    International Nuclear Information System (INIS)

    Sakai, Tomohiro; Naito, Yoshitaka; Komuro, Yuichi.

    1988-08-01

    A method to determine ''full reflector thickness'' and ''isolation thickness'', which is utilized for criticality safety evaluation on nuclear fuel facilities, was proposed in this paper. Firstly, a calculation was tryed to obtain the two kinds of thicknesses from the result of criticality calculations for a specific case. Then, two simple equations which calculates the two kinds of thicknesses were made from the relation between reflector (or isolator) thickness and k eff , and one-group diffusion theory. Finally, we proposed a new method to determine the thicknesses. From the method we proposed, ''full reflector thickness'' and ''isolation thickness'' can be obtain using the equations and migration length of the reflector (or isolator) and infinite and effective multiplication factor of the fuel. (author)

  6. Thickness dependence of magnetoelectric response for composites of Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} films on CoFe{sub 2}O{sub 4} ceramic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jing, E-mail: wang-jing@nuaa.edu.cn; Zhu, Kongjun [State Key Laboratory of Mechanics and Control of Mechanical Structures, College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Wu, Xia; Deng, Chaoyong [School of Electronics and Information Engineering, Guizhou University, Guiyang 550025 (China); Peng, Renci; Wang, Jianjun [School of Materials Science and Engineering, and State Key Lab of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China)

    2014-08-15

    Using chemical solution spin-coating we grew Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} films of different thicknesses on highly dense CoFe{sub 2}O{sub 4} ceramics. X-ray diffraction revealed no other phases except Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} and CoFe{sub 2}O{sub 4}. In many of these samples we observed typical ferroelectric hysteresis loops, butterfly-shaped piezoelectric strains, and the magnetic-field-dependent magnetostriction. These behaviors caused appreciable magnetoelectric responses based on magnetic-mechanical-electric coupling. Our results indicated that the thickness of the Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} film was important in obtaining strong magnetoelectric coupling.

  7. Ultrasonographic assessment of the diaphragm in chronic obstructive pulmonary disease patients: relationships with pulmonary function and the influence of body composition - a pilot study.

    Science.gov (United States)

    Smargiassi, Andrea; Inchingolo, Riccardo; Tagliaboschi, Linda; Di Marco Berardino, Alessandro; Valente, Salvatore; Corbo, Giuseppe Maria

    2014-01-01

    Skeletal muscle weakness with loss of fat-free mass (FFM) is one of the main systemic effects of chronic obstructive pulmonary disease (COPD). The diaphragm is also involved, leading to disadvantageous conditions and poor contractile capacities. We measured the thickness of the diaphragm (TD) by ultrasonography to evaluate the relationships between echographic measurements, parameters of respiratory function and body composition data. Thirty-two patients (23 males) underwent (1) pulmonary function tests, (2) echographic assessment of TD in the zone of apposition at various lung volumes, i.e. TD at residual volume (TDRV), TD at functional residual capacity (TDFRC) and TD at total lung capacity (TDTLC), and (3) bioelectrical body impedance analysis. The BMI and the BODE (BMI-Obstruction-Dyspnea-Exercise) index values were reported. TDRV, TDFRC and TDTLC measured 3.3, 3.6 and 6 mm, respectively, with good intraobserver reproducibility (0.97, 0.97 and 0.96, respectively). All the TDs were found to be related to FFM, with the relationship being greater for TDFRC (r(2) = 0.39 and p = 0.0002). With regard to lung volumes, inspiratory capacity (IC) was found to be closely related to TDTLC (r(2) = 0.42 and p = 0.0001). The difference between TDTLC and TDRV, as a thickening value (TDTLCRV), was closely related to FVC (r(2) = 0.34 and p = 0.0004) and to air-trapping indices (RV/TLC, FRC/TLC and IC/TLC): the degree of lung hyperinflation was greater and the TDTLCRV was less. Finally, we found a progressive reduction of both thicknesses and thickenings as the severity of IC/TLC increased, with a significant p value for the trend in both analyses (p = 0.02). Ultrasonographic assessment of the diaphragm could be a useful tool for studying disease progression in COPD patients, in terms of lung hyperinflation and the loss of FFM. © 2014 S. Karger AG, Basel.

  8. Method of working thick beds

    Energy Technology Data Exchange (ETDEWEB)

    Giezynski, A; Bialasik, A; Krawiec, A; Wylenzek, A

    1981-12-30

    The patented method of working thick coal beds in layers consists of creating in the collapsed rocks or from the fill material a bearing rock plate by strengthening these rocks with a hardening composition made of wastes of raw material, resin and water injected into the rock through wells. The difference in the suggestion is that through boreholes drilled in the lower part of the rock roofing on a previously calculated network, a solution is regularly injected which consists of dust wastes obtained in electric filters during production of clinker from mineral raw material in a quantity of 60-70% by volume, wastes of open-hearth production in a quantity of 15-20% and natural sand in a quantity of 15-20%, and water in a quantity of 35-55% of the volume of mineral components. In the second variant, the injected compostion contains: wastes from production of clinker 55-57%, open-hearth wastes 20-23%, natural sand 12-14%, asbestos fine particles 7-8% and water 38-45% of the volume of mineral components. In addition, the difference is that in the boreholes drilled in the coal block directly under the roofing, a composition is injected which consists of natural sand and catalyst in the form of powder and individually supplied liquid synthetic resin in a quantity of 3-5% by weight in relation to the sand. The hardening time with normal temperature is 1-1.5 h, after which strength is reached of 80 kg-f/cm/sup 2/.

  9. Radioactive thickness gauge (1962)

    International Nuclear Information System (INIS)

    Guizerix, J.

    1962-01-01

    The author describes a thickness gauge in which the scintillating crystal detector alternately 'sees' a radioactive source through the material which is to be measured and then a control source of the same material; the radiations are separated in time by an absorbing valve whose sections are alternately full and hollow. The currents corresponding to the two sources are separated beyond the photomultiplier tube by a detector synchronized with the rotation of the valve. The quotient of these two currents is then obtained with a standard recording potentiometer. It is found that the average value of the response which is in the form G = f(I 1 /I 2 ) is not affected by decay of the radioactive sources, and that it is little influenced by variations of high tension, temperature, or properties of the air in the source detector interval. The performance of the gauge is given. (author) [fr

  10. Thick-Big Descriptions

    DEFF Research Database (Denmark)

    Lai, Signe Sophus

    The paper discusses the rewards and challenges of employing commercial audience measurements data – gathered by media industries for profitmaking purposes – in ethnographic research on the Internet in everyday life. It questions claims to the objectivity of big data (Anderson 2008), the assumption...... communication systems, language and behavior appear as texts, outputs, and discourses (data to be ‘found’) – big data then documents things that in earlier research required interviews and observations (data to be ‘made’) (Jensen 2014). However, web-measurement enterprises build audiences according...... to a commercial logic (boyd & Crawford 2011) and is as such directed by motives that call for specific types of sellable user data and specific segmentation strategies. In combining big data and ‘thick descriptions’ (Geertz 1973) scholars need to question how ethnographic fieldwork might map the ‘data not seen...

  11. Disentangling The Thick Concept Argument

    DEFF Research Database (Denmark)

    Blomberg, Olle

    2007-01-01

    Critics argue that non-cognitivism cannot adequately account for the existence and nature of some thick moral concepts. They use the existence of thick concepts as a lever in an argument against non-cognitivism, here called the Thick Concept Argument (TCA). While TCA is frequently invoked...

  12. Determination of accurate metal silicide layer thickness by RBS

    International Nuclear Information System (INIS)

    Kirchhoff, J.F.; Baumann, S.M.; Evans, C.; Ward, I.; Coveney, P.

    1995-01-01

    Rutherford Backscattering Spectrometry (RBS) is a proven useful analytical tool for determining compositional information of a wide variety of materials. One of the most widely utilized applications of RBS is the study of the composition of metal silicides (MSi x ), also referred to as polycides. A key quantity obtained from an analysis of a metal silicide is the ratio of silicon to metal (Si/M). Although compositional information is very reliable in these applications, determination of metal silicide layer thickness by RBS techniques can differ from true layer thicknesses by more than 40%. The cause of these differences lies in how the densities utilized in the RBS analysis are calculated. The standard RBS analysis software packages calculate layer densities by assuming each element's bulk densities weighted by the fractional atomic presence. This calculation causes large thickness discrepancies in metal silicide thicknesses because most films form into crystal structures with distinct densities. Assuming a constant layer density for a full spectrum of Si/M values for metal silicide samples improves layer thickness determination but ignores the underlying physics of the films. We will present results of RBS determination of the thickness various metal silicide films with a range of Si/M values using a physically accurate model for the calculation of layer densities. The thicknesses are compared to scanning electron microscopy (SEM) cross-section micrographs. We have also developed supporting software that incorporates these calculations into routine analyses. (orig.)

  13. Pembuatan Adhesive Bridge dengan Fiber Reinforced Composite untuk Perawatan Kehilangan dan Kegoyahan Gigi Anterior Rahang Bawah

    Directory of Open Access Journals (Sweden)

    Demmy Wijaya

    2014-06-01

    Full Text Available Salah satu perawatan kehilangan gigi anterior untuk tujuan estetis adalah dengan adhesive bridge. Fiber Reinforced Composite (FRC adalah bahan struktural yang terdiri dari 2 konstituen yang berbeda. Komponen penguat (fiber memberikan kekuatan dan kekakuan, sedangkan matriks (resin komposit mendukung penguatan. Bahan FRC dapat digunakan untuk pembuatan adhesive bridge dan juga dapat digunakan sebagai stabilisasi gigi yang mengalami kegoyahan. Adanya gigi pendukung yang sehat juga sangat membantu keberhasilan perawatan ini. Laporan kasus ini bertujuan untuk memberikan informasi tentang penatalaksanaan perawatan kehilangan dan kegoyahan gigi anterior rahang bawah menggunakan FRC. Seorang pasien laki-laki berusia 33 tahun datang ke klinik Prostodonsia RSGM Prof. Soedomo ingin dibuatkan gigi tiruan. Pasien kehilangan gigi 31, gigi 32, gigi 41 dan mengalami kegoyahan derajat 2 disertai resesi gingiva. Kondisi tersebut akibat pasca pembuatan gigi tiruan di tukang gigi. Pasien tidak ingin giginya yang goyah dilakukan pencabutan. Tatalaksana kasus: pencetakan rahang untuk model diagnostik, pembuatan mock-up pontik gigi 31 pada model diagnostik, pembuatan index dengan mencetak bagian lingual dan 1/3 incisal menggunakan putty, preparasi gigi penyangga (gigi 32, 33, 41, 42, 43, pemasangan fiber dengan bantuan index putty, pembentukan bagian labial pontik dengan komposit, finishing dan polishing. Kesimpulan: Fiber reinforced composite dapat dipakai untuk pengelolaan pasien yang mengalami kehilangan dan kegoyahan gigi anterior rahang bawah. Adhesive Bridge of Fiber Reinforced Composite to Treat Tooth Missing and Luxation of Lower Anterior Teeth. One of the anterior tooth loss treatments for esthetic purposes is the adhesive bridge. Fiber Reinforced Composite (FRC is a structural material that consists of two different constituencies. Amplifier components (fiber provide strength and stiffness, while matrix (resin composite support reinforcement. FRC materials

  14. Composite lamination method

    Science.gov (United States)

    Dickerson, G. E. (Inventor)

    1977-01-01

    A process was developed for preparing relatively thick composite laminate structure wherein thin layers of prepreg tapes are assembled, these thin layers are cut into strips that are partially cured, and stacked into the desired thickness with uncured prepreg disposed between each layer of strips. The formed laminate is finally cured and thereafter machined to the desired final dimensions.

  15. Optimum target thickness for polarimeters

    International Nuclear Information System (INIS)

    Sitnik, I.M.

    2003-01-01

    Polarimeters with thick targets are a tool to measure the proton polarization. But the question about the optimum target thickness is still the subject of discussion. An attempt to calculate the most common parameters concerning this problem, in a few GeV region, is made

  16. Thickness-Dependent Bioelectrochemical and Energy Applications of Thickness-Controlled Meso-Macroporous Antimony-Doped Tin Oxide

    Directory of Open Access Journals (Sweden)

    Daniel Mieritz

    2018-04-01

    Full Text Available Coatings of hierarchically meso-macroporous antimony-doped tin oxide (ATO enable interfacing adsorbed species, such as biomacromolecules, with an electronic circuit. The coating thickness is a limiting factor for the surface coverage of adsorbates, that are electrochemically addressable. To overcome this challenge, a carbon black-based templating method was developed by studying the composition of the template system, and finding the right conditions for self-standing templates, preventing the reaction mixture from flowing out of the mask. The thicknesses of as-fabricated coatings were measured using stylus profilometry to establish a relationship between the mask thickness and the coating thickness. Cyclic voltammetry was performed on coatings with adsorbed cytochrome c to check whether the entire coating thickness was electrochemically addressable. Further, bacterial photosynthetic reaction centers were incorporated into the coatings, and photocurrent with respect to coating thickness was studied. The template mixture required enough of both carbon black and polymer, roughly 7% carbon black and 6% poly(ethylene glycol. Coatings were fabricated with thicknesses approaching 30 µm, and thickness was shown to be controllable up to at least 15 µm. Under the experimental conditions, photocurrent was found to increase linearly with the coating thickness, up to around 12 µm, above which were diminished gains.

  17. Development of an Overlay Design Procedure for Composite Pavements

    Science.gov (United States)

    2017-09-01

    The composite overlay design procedure currently used by ODOT sometimes produces very large overlay thicknesses that are deemed structurally unnecessary, especially for composite pavements already with thick asphalt overlays. This study was initiated...

  18. A Pilot Study Providing Evidence for a Relationship between a Composite Lifestyle Score and Risk of Higher Carotid Intima-Media Thickness: Is There a Link to Oxidative Stress?

    Directory of Open Access Journals (Sweden)

    Neda Seyedsadjadi

    2018-01-01

    Full Text Available Lifestyle behaviours have been closely linked to the progressive cell damage associated with oxidative stress (OS and the development of cardiovascular disease (CVD. Early detection of lifestyle-linked OS may therefore be useful in the early identification of prodromal disease. To test this hypothesis, this study assessed the relationship between a comprehensive redox balance lifestyle score (RBLS and carotid intima-media thickness (CIMT, a recognized marker for CVD, and plasma biomarkers of OS. In a cross-sectional study design, 100 apparently healthy middle-aged participants were asked to complete a comprehensive lifestyle questionnaire, followed by DXA scanning, CIMT ultrasonography, and blood collection. The RBLS was composed of lifestyle components with pro- and antioxidant properties with a higher score indicative of lower oxidative activity. Multiple linear regression and logistic regression analysis were performed for statistical analysis. The RBLS was significantly associated with the risk for increased CIMT that was independent of conventional CVD risk factors (χ29=35.60, P≤0.001. The adjusted model explained 42.4% of the variance in CIMT. Participants with RBLS below the median were at significantly increased risk of higher CIMT compared to participants with RBLS above the median (OR=3.60, 95% CI: 1.19–10.88, P=0.023. Significant associations were also observed between the RBLS, plasma total antioxidant capacity (TAC (r99=0.28, P=0.006, hydroperoxide (HPX (rs99=−0.28, P=0.005, TAC/HPX ratio (r98=0.41, P≤0.001, γ-glutamyltransferase (r97=−0.23, P=0.024, uric acid (r98=−0.20, P=0.045, and inflammatory C-reactive protein (rs97=−0.25, P=0.012 and interleukin-1β (r97=−0.21, P=0.040. These findings highlight the importance of identifying the collective influence of lifestyle behaviours on OS activity and its potential to remodel the vascular endothelium.

  19. Self-heating forecasting for thick laminate specimens in fatigue

    Science.gov (United States)

    Lahuerta, F.; Westphal, T.; Nijssen, R. P. L.

    2014-12-01

    Thick laminate sections can be found from the tip to the root in most common wind turbine blade designs. Obtaining accurate and reliable design data for thick laminates is subject of investigations, which include experiments on thick laminate coupons. Due to the poor thermal conductivity properties of composites and the material self-heating that occurs during the fatigue loading, high temperature gradients may appear through the laminate thickness. In the case of thick laminates in high load regimes, the core temperature might influence the mechanical properties, leading to premature failures. In the present work a method to forecast the self-heating of thick laminates in fatigue loading is presented. The mechanical loading is related with the laminate self-heating, via the cyclic strain energy and the energy loss ratio. Based on this internal volumetric heat load a thermal model is built and solved to obtain the temperature distribution in the transient state. Based on experimental measurements of the energy loss factor for 10mm thick coupons, the method is described and the resulting predictions are compared with experimental surface temperature measurements on 10 and 30mm UD thick laminate specimens.

  20. Multi-layer porous fiber-reinforced composites for implants: in vitro calcium phosphate formation in the presence of bioactive glass.

    Science.gov (United States)

    Nganga, Sara; Zhang, Di; Moritz, Niko; Vallittu, Pekka K; Hupa, Leena

    2012-11-01

    Glass-fiber-reinforced composites (FRCs), based on bifunctional methacrylate resin, have recently shown their potential for use as durable cranioplasty, orthopedic and oral implants. In this study we suggest a multi-component sandwich implant structure with (i) outer layers out of porous FRC, which interface the cortical bone, and (ii) inner layers encompassing bioactive glass granules, which interface with the cancellous bone. The capability of Bioglass(®) 45S5 granules (100-250μm) to induce calcium phosphate formation on the surface of the FRC was explored by immersing the porous FRC-Bioglass laminates in simulated body fluid (SBF) for up to 28d. In both static (agitated) and dynamic conditions, bioactive glass granules induced precipitation of calcium phosphate at the laminate surfaces as confirmed by scanning electron microscopy. The proposed dynamic flow system is useful for the in vitro simulation of bone-like apatite formation on various new porous implant designs containing bioactive glass and implant material degradation. Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  1. Dielectrophoretic capture of low abundance cell population using thick electrodes

    OpenAIRE

    Marchalot, Julien; Chateaux, Jean-François; Faivre, Magalie; Mertani, Hichem C.; Ferrigno, Rosaria; Deman, Anne-Laure

    2015-01-01

    Enrichment of rare cell populations such as Circulating Tumor Cells (CTCs) is a critical step before performing analysis. This paper presents a polymeric microfluidic device with integrated thick Carbon-PolyDimethylSiloxane composite (C-PDMS) electrodes designed to carry out dielectrophoretic (DEP) trapping of low abundance biological cells. Such conductive composite material presents advantages over metallic structures. Indeed, as it combines properties of both the matrix and doping particle...

  2. Corneal thickness: measurement and implications.

    Science.gov (United States)

    Ehlers, Niels; Hjortdal, Jesper

    2004-03-01

    The thickness of the cornea was reported in more than 100-year-old textbooks on physiological optics (Helmholtz, Gullstrand). Physiological interest was revived in the 1950s by David Maurice, and over the next 50 years, this 'simple' biological parameter has been studied extensively. Several techniques for its measurement have been described and physiological and clinical significance have been studied. In this review, the different methods and techniques of measurement are briefly presented (optical, ultrasound). While the corneal thickness of many animals are the same over a considerable part of the surface, in the human cornea anterior and posterior curvature are not concentric giving rise to a problem of definition. Based on this the precision and accuracy of determining the central corneal thickness are discussed. Changes in corneal thickness reflects changes in function of the boundary layers, in particular the endothelial barrier. The absolute value of thickness is of importance for the estimation of IOP but also in diagnosis of corneal and systemic disorders. Finally it is discussed to what extent the thickness is a biometric parameter of significance, e.g. in the progression of myopia or in the development of retinal detachment.

  3. Influence of processing parameters on PZT thick films

    International Nuclear Information System (INIS)

    Huang, Oliver; Bandyopadhyay, Amit; Bose, Susmita

    2005-01-01

    We have studied influence of processing parameters on the microstructure and ferroelectric properties of lead zirconate titanate (PZT)-based thick films in the range of 5-25 μm. PZT and 2% La-doped PZT thick films were processed using a modified sol-gel process. In this process, PZT- and La-doped PZT powders were first prepared via sol-gel. These powders were calcined and then used with respective sols to form a slurry. Slurry composition was optimized to spin-coat thick films on platinized Si substrate (Si/SiO 2 /Ti/Pt). Spinning rate, acceleration and slurry deposition techniques were optimized to form thick films with uniform thickness and without any cracking. Increasing solids loading was found to enhance the surface smoothness of the film and decrease porosity. Films were tested for their electrical properties and ferroelectric fatigue response. The maximum polarization obtained was 40 μC/cm 2 at 250 kV/cm for PZT thick film and 30 μC/cm 2 at 450 kV/cm for La-doped PZT thick film. After 10 9 cycles of fatiguing at 35 kHz, La-doped PZT showed better resistance for ferroelectric fatigue compared with un-doped PZT films

  4. Composite Material Switches

    Science.gov (United States)

    Javadi, Hamid (Inventor)

    2002-01-01

    A device to protect electronic circuitry from high voltage transients is constructed from a relatively thin piece of conductive composite sandwiched between two conductors so that conduction is through the thickness of the composite piece. The device is based on the discovery that conduction through conductive composite materials in this configuration switches to a high resistance mode when exposed to voltages above a threshold voltage.

  5. Radioisotope albedo method for measuring thickness of polymers coatings on metal basis

    International Nuclear Information System (INIS)

    Kapranov, B.I.; Myakin'kova, L.V.; Shaverin, V.A.

    1986-01-01

    Theoretical analysis of albedo thickness measuring of polymer coating-metal composite has been made and experimental studies of the range of tested thicknesses of polymer coating when different metal bases and radiation sources are used have been conducted. It is shown that the thickness of polymer coating on metal can be measured using backscattered γ-radiation in the energy range of 20-120 keV at the error 0.15-0.8 mm, at that, for thickness up to 23 mm the use of 147 Pm isotope can be defined as the optimum one; for thicknesses up to 40 mm 241 Am should be used; at thicknesses up to 60 mm - 57 Co. The AGAT-1 albedo gamma thickness gage, designed for measuring thickness of fiber glass coating up to 20 mm on metal base, is described

  6. Are galaxy discs optically thick?

    International Nuclear Information System (INIS)

    Disney, Michael; Davies, Jonathan; Phillipps, Steven

    1989-01-01

    We re-examine the classical optical evidence for the low optical depths traditionally assigned to spiral discs and argue that it is highly model-dependent and unconvincing. In particular, layered models with a physically thin but optically thick dust layer behave like optically thin discs. The opposite hypotheses, that such discs are optically thick is then examined in the light of modern evidence. We find it to be consistent with the near-infrared and IRAS observations, with the surface brightnesses, with the HI and CO column densities and with the Hα measurements. (author)

  7. Interfacial fracture of dentin adhesively bonded to quartz-fiber reinforced composite

    International Nuclear Information System (INIS)

    Melo, Renata M.; Rahbar, Nima; Soboyejo, Wole

    2011-01-01

    The paper presents the results of an experimental study of interfacial failure in a multilayered structure consisting of a dentin/resin cement/quartz-fiber reinforced composite (FRC). Slices of dentin close to the pulp chamber were sandwiched by two half-circle discs made of a quartz-fiber reinforced composite, bonded with bonding agent (All-bond 2, BISCO, Schaumburg) and resin cement (Duo-link, BISCO, Schaumburg) to make Brazil-nut sandwich specimens for interfacial toughness testing. Interfacial fracture toughness (strain energy release rate, G) was measured as a function of mode mixity by changing loading angles from 0 deg. to 15 deg. The interfacial fracture surfaces were then examined using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX) to determine the failure modes when loading angles changed. A computational model was also developed to calculate the driving forces, stress intensity factors and mode mixities. Interfacial toughness increased from ∼ 1.5 to 3.2 J/m 2 when the loading angle increases from ∼ 0 to 15 deg. The hybridized dentin/cement interface appeared to be tougher than the resin cement/quartz-fiber reinforced epoxy. The Brazil-nut sandwich specimen was a suitable method to investigate the mechanical integrity of dentin/cement/FRC interfaces.

  8. [Endoscopic full-thickness resection].

    Science.gov (United States)

    Meier, B; Schmidt, A; Caca, K

    2016-08-01

    Conventional endoscopic resection techniques such as endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) are powerful tools for the treatment of gastrointestinal (GI) neoplasms. However, those techniques are limited to the superficial layers of the GI wall (mucosa and submucosa). Lesions without lifting sign (usually arising from deeper layers) or lesions in difficult anatomic positions (appendix, diverticulum) are difficult - if not impossible - to resect using conventional techniques, due to the increased risk of complications. For larger lesions (>2 cm), ESD appears to be superior to the conventional techniques because of the en bloc resection, but the procedure is technically challenging, time consuming, and associated with complications even in experienced hands. Since the development of the over-the-scope clips (OTSC), complications like bleeding or perforation can be endoscopically better managed. In recent years, different endoscopic full-thickness resection techniques came to the focus of interventional endoscopy. Since September 2014, the full-thickness resection device (FTRD) has the CE marking in Europe for full-thickness resection in the lower GI tract. Technically the device is based on the OTSC system and combines OTSC application and snare polypectomy in one step. This study shows all full-thickness resection techniques currently available, but clearly focuses on the experience with the FTRD in the lower GI tract.

  9. Electron beam curable polymer thick film

    International Nuclear Information System (INIS)

    Nagata, Hidetoshi; Kobayashi, Takashi

    1988-01-01

    Currently, most printed circuit boards are produced by the selective etching of copper clads laminated on dielectric substrates such as paper/phenolic resion or nonwoven glass/epoxy resin composites. After the etchig, various components such as transistors and capacitors are mounted on the boards by soldering. But these are troublesome works, therefore, as an alternative, printing method has been investigated recently. In the printing method, conductor circuits and resistors can be made by printing and curing of the specially prepared paste on dielectric substrates. In the near future, also capacitors are made by same method. Usually, conductor paste, resistor paste and dielectric paste are employed, and in this case, the printing is screen printing, and the curing is done thermally. In order to avoid heating and the deterioration of substrates, attention was paid to electron beam curing, and electron beam curable polymer thick film system was developed. The electron beam curable paste is the milled mixture of a filler and an electron beam curable binder of oligomer/monomer. The major advantage of electron beam curable polymer thick film, the typical data of a printed resistor of this type and its trial are reported. (K.I.)

  10. Gammatography of thick lead vessels

    International Nuclear Information System (INIS)

    Raghunath, V.M.; Bhatnagar, P.K.; Sundaram, V.M.

    1979-01-01

    Radiography, scintillation and GM counting and dose measurements using ionisation chamber equipment are commonly used for detecting flaws/voids in materials. The first method is mostly used for steel vessels and to a lesser extent thin lead vessels also and is essentially qualitative. Dose measuring techniques are used for very thick and large lead vessels for which high strength radioactive sources are required, with its inherent handling problems. For vessels of intermediate thicknesses, it is ideal to use a small strength source and a GM or scintillation counter assembly. At the Reactor Research Centre, Kalpakkam, such a system was used for checking three lead vessels of thicknesses varying from 38mm to 65mm. The tolerances specified were +- 4% variation in lead thickness. The measurements also revealed the non concentricity of one vessel which had a thickness varying from 38mm to 44mm. The second vessel was patently non-concentric and the dimensional variation was truly reproduced in the measurements. A third vessel was fabricated with careful control of dimensions and the measurements exhibited good concentricity. Small deviations were observed, attributable to imperfect bondings between steel and lead. This technique has the following advantages: (a) weaker sources used result in less handling problems reducing the personnel exposures considerably; (b) the sensitivity of the instrument is quite good because of better statistics; (c) the time required for scanning a small vessel is more, but a judicious use of a scintillometer for initial fast scan will help in reducing the total scanning time; (d) this method can take advantage of the dimensional variations themselves to get the calibration and to estimate the deviations from specified tolerances. (auth.)

  11. Thick resist for MEMS processing

    Science.gov (United States)

    Brown, Joe; Hamel, Clifford

    2001-11-01

    The need for technical innovation is always present in today's economy. Microfabrication methods have evolved in support of the demand for smaller and faster integrated circuits with price performance improvements always in the scope of the manufacturing design engineer. The dispersion of processing technology spans well beyond IC fabrication today with batch fabrication and wafer scale processing lending advantages to MEMES applications from biotechnology to consumer electronics from oil exploration to aerospace. Today the demand for innovative processing techniques that enable technology is apparent where only a few years ago appeared too costly or not reliable. In high volume applications where yield and cost improvements are measured in fractions of a percent it is imperative to have process technologies that produce consistent results. Only a few years ago thick resist coatings were limited to thickness less than 20 microns. Factors such as uniformity, edge bead and multiple coatings made high volume production impossible. New developments in photoresist formulation combined with advanced coating equipment techniques that closely controls process parameters have enable thick photoresist coatings of 70 microns with acceptable uniformity and edge bead in one pass. Packaging of microelectronic and micromechanical devices is often a significant cost factor and a reliability issue for high volume low cost production. Technologies such as flip- chip assembly provide a solution for cost and reliability improvements over wire bond techniques. The processing for such technology demands dimensional control and presents a significant cost savings if it were compatible with mainstream technologies. Thick photoresist layers, with good sidewall control would allow wafer-bumping technologies to penetrate the barriers to yield and production where costs for technology are the overriding issue. Single pass processing is paramount to the manufacturability of packaging

  12. In vitro evaluation of fracture resistance of Fiber-Reinforced Composite inlay bridges in upper anterior and lower posterior teeth

    Directory of Open Access Journals (Sweden)

    Jalalian E.

    2007-07-01

    Full Text Available Background and Aim: Considering flexural strength of fiber-reinforced composites (FRC and also the role of conservative cavities in protecting sound tissue of abutments, the aim of this study was to evaluate the fracture resistance of these bridges by handmade samples in vitro.Materials and Methods: In this experimental in vitro study, 44 sound newly extracted teeth were used to make 22 fixed inlay bridges including 11 three unit anterior upper inlay bridges substituting clinical model of upper central and 11 three unit posterior lower inlay bridges substituting clinical model of lower first molar. Specimens were prepared with FRC and mounted with artificial PDL in acryl. Cases were exposed to final load by using Universal Testing Machine (Instron 1195 with the speed of 1 mm/min. Statistical analysis was performed by Kolmogorov- Smirnov, independent sample T and Kaplan-Meier tests with p<0.05 as the level of significance.Results: Based on the statistical tests, the 95% confidence interval of mean was 450-562 N in anterior and  1473- 1761 N in posterior area. Fracture strength was high in the studied groups. Fractures in both groups occurred on composite facing, and the framework remained intact. The highest percentage of fracture in posterior teeth was in the middle of pontic towards the distal connector and in the anterior teeth in the lateral connector, between central pontic and lateral abutment. Using the independent sample T  test a significant statistical difference was observed between two groups (P<0.001. The fracture resistance of anterior samples was lower than the posterior ones.Conclusion: Based on the results of this study regarding the high fracture resistance in both areas FRC inlay bridges could be recommended for upper anterior and lower posterior teeth in clinical dentistry certainly more studies are needed to ascertain this treatment option.

  13. Fiber composites as a method of treatment splinting tooth mobility in chronic periodontitis

    Directory of Open Access Journals (Sweden)

    Dewi Lidya Ichwana

    2016-12-01

    Full Text Available Patients with periodontal disease can lead to severe tooth mobility so often complains of pain when eating, decreased chewing ability and functional occlusion. Tooth mobility is a movement in a horizontal or vertical direction and one of the most unpleased effects from periodontal disease. Basically, tooth mobility is not a disease that requires treatment, but it is a symptom of periodontal tissue morphology changes, so it became a challenge for dentists in making decisions to maintain proper care of the teeth. Recent studies improved the use of periodontal splint with fiber reinforced composite (FRC or fiber composite may lead to a long-term prognosis of teeth mobility due to periodontal disase. The case report describes treatment of chronic periodontitis patients with splinting fiber composites as a method for stabilization of the lower anterior teeth providing aesthetics, comfort, improved functionality occlusion, mastication and a good prognosis.

  14. Microscopic morphological compensation for phase-separated composite film thickness

    International Nuclear Information System (INIS)

    Chang, C. H.; Chan, Y. C.; Wan, Z.

    2007-01-01

    The generic structure of our bimeso gens is shown in and for a typical blue-phase mixture of the type we describe here we use mixtures of the ratio 33.4% (n =2.6), 34.1% (n =6.57), 36.6% (n 11.15) with of the high twisted power (HTP) agent BD H1381 (Full text available from Merck Chemicals and described in ref. We then studied the electric-field dependency of the selective reflection in BP I * at 20.7 degree C by applying increasing and the decreasing pulsed alternating current (a.c.) electric fields (100 Hz)

  15. Nondestructive method to coat thickness measurements through X-ray fluorescence

    International Nuclear Information System (INIS)

    Sanchez, F.

    1986-01-01

    It's described a system that permits thickness measurement and composition of Sn-Pb alloys to simultaneous measurement of Au over Ni over any base, beyond convestionals measurements, including flash coats or touch. (C.M.) [pt

  16. Self-heating forecasting for thick laminates testing coupons in fatigue

    NARCIS (Netherlands)

    Lahuerta, F.; Westphal, T.; Nijssen, R.P.L.

    2012-01-01

    Thick laminate sections can be found from the tip to the root in most common wind turbine blade designs. Obtaining accurate and reliable design data for thick laminates is subject of investigations. Due to the poor thermal conductivity properties of composites and the material self-heating that

  17. Accurate thickness measurement of graphene

    International Nuclear Information System (INIS)

    Shearer, Cameron J; Slattery, Ashley D; Stapleton, Andrew J; Shapter, Joseph G; Gibson, Christopher T

    2016-01-01

    Graphene has emerged as a material with a vast variety of applications. The electronic, optical and mechanical properties of graphene are strongly influenced by the number of layers present in a sample. As a result, the dimensional characterization of graphene films is crucial, especially with the continued development of new synthesis methods and applications. A number of techniques exist to determine the thickness of graphene films including optical contrast, Raman scattering and scanning probe microscopy techniques. Atomic force microscopy (AFM), in particular, is used extensively since it provides three-dimensional images that enable the measurement of the lateral dimensions of graphene films as well as the thickness, and by extension the number of layers present. However, in the literature AFM has proven to be inaccurate with a wide range of measured values for single layer graphene thickness reported (between 0.4 and 1.7 nm). This discrepancy has been attributed to tip-surface interactions, image feedback settings and surface chemistry. In this work, we use standard and carbon nanotube modified AFM probes and a relatively new AFM imaging mode known as PeakForce tapping mode to establish a protocol that will allow users to accurately determine the thickness of graphene films. In particular, the error in measuring the first layer is reduced from 0.1–1.3 nm to 0.1–0.3 nm. Furthermore, in the process we establish that the graphene-substrate adsorbate layer and imaging force, in particular the pressure the tip exerts on the surface, are crucial components in the accurate measurement of graphene using AFM. These findings can be applied to other 2D materials. (paper)

  18. Soliton models for thick branes

    International Nuclear Information System (INIS)

    Peyravi, Marzieh; Riazi, Nematollah; Lobo, Francisco S.N.

    2016-01-01

    In this work, we present new soliton solutions for thick branes in 4+1 dimensions. In particular, we consider brane models based on the sine-Gordon (SG), φ 4 and φ 6 scalar fields, which have broken Z 2 symmetry in some cases and are responsible for supporting and stabilizing the thick branes. The origin of the symmetry breaking in these models resides in the fact that the modified scalar field potential may have non-degenerate vacua. These vacua determine the cosmological constant on both sides of the brane. We also study the geodesic equations along the fifth dimension, in order to explore the particle motion in the neighborhood of the brane. Furthermore, we examine the stability of the thick branes, by determining the sign of the w 2 term in the expansion of the potential for the resulting Schroedinger-like equation, where w is the five-dimensional coordinate. It turns out that the φ 4 brane is stable, while there are unstable modes for certain ranges of the model parameters in the SG and φ 6 branes. (orig.)

  19. Soliton models for thick branes

    Energy Technology Data Exchange (ETDEWEB)

    Peyravi, Marzieh [Ferdowsi University of Mashhad, Department of Physics, School of Sciences, Mashhad (Iran, Islamic Republic of); Riazi, Nematollah [Shahid Beheshti University, Physics Department, Tehran (Iran, Islamic Republic of); Lobo, Francisco S.N. [Faculdade de Ciencias da Universidade de Lisboa, Instituto de Astrofisica e Ciencias do Espaco, Lisbon (Portugal)

    2016-05-15

    In this work, we present new soliton solutions for thick branes in 4+1 dimensions. In particular, we consider brane models based on the sine-Gordon (SG), φ{sup 4} and φ{sup 6} scalar fields, which have broken Z{sub 2} symmetry in some cases and are responsible for supporting and stabilizing the thick branes. The origin of the symmetry breaking in these models resides in the fact that the modified scalar field potential may have non-degenerate vacua. These vacua determine the cosmological constant on both sides of the brane. We also study the geodesic equations along the fifth dimension, in order to explore the particle motion in the neighborhood of the brane. Furthermore, we examine the stability of the thick branes, by determining the sign of the w{sup 2} term in the expansion of the potential for the resulting Schroedinger-like equation, where w is the five-dimensional coordinate. It turns out that the φ{sup 4} brane is stable, while there are unstable modes for certain ranges of the model parameters in the SG and φ{sup 6} branes. (orig.)

  20. The crustal thickness of Australia

    Science.gov (United States)

    Clitheroe, G.; Gudmundsson, O.; Kennett, B.L.N.

    2000-01-01

    We investigate the crustal structure of the Australian continent using the temporary broadband stations of the Skippy and Kimba projects and permanent broadband stations. We isolate near-receiver information, in the form of crustal P-to-S conversions, using the receiver function technique. Stacked receiver functions are inverted for S velocity structure using a Genetic Algorithm approach to Receiver Function Inversion (GARFI). From the resulting velocity models we are able to determine the Moho depth and to classify the width of the crust-mantle transition for 65 broadband stations. Using these results and 51 independent estimates of crustal thickness from refraction and reflection profiles, we present a new, improved, map of Moho depth for the Australian continent. The thinnest crust (25 km) occurs in the Archean Yilgarn Craton in Western Australia; the thickest crust (61 km) occurs in Proterozoic central Australia. The average crustal thickness is 38.8 km (standard deviation 6.2 km). Interpolation error estimates are made using kriging and fall into the range 2.5-7.0 km. We find generally good agreement between the depth to the seismologically defined Moho and xenolith-derived estimates of crustal thickness beneath northeastern Australia. However, beneath the Lachlan Fold Belt the estimates are not in agreement, and it is possible that the two techniques are mapping differing parts of a broad Moho transition zone. The Archean cratons of Western Australia appear to have remained largely stable since cratonization, reflected in only slight variation of Moho depth. The largely Proterozoic center of Australia shows relatively thicker crust overall as well as major Moho offsets. We see evidence of the margin of the contact between the Precambrian craton and the Tasman Orogen, referred to as the Tasman Line. Copyright 2000 by the American Geophysical Union.

  1. Influence of target thickness on the release of radioactive atoms

    Energy Technology Data Exchange (ETDEWEB)

    Guillot, Julien, E-mail: guillotjulien@ipno.in2p3.fr [Institut de Physique Nucléaire CNRS/IN2P3 UMR 8608 – Université Paris Sud – Université Paris Saclay, F-91406 Orsay Cedex (France); Roussière, Brigitte [Institut de Physique Nucléaire CNRS/IN2P3 UMR 8608 – Université Paris Sud – Université Paris Saclay, F-91406 Orsay Cedex (France); Tusseau-Nenez, Sandrine [Physique de la Matière Condensée Ecole Polytechnique/CNRS UMR 7643 – Université Paris Saclay, F-91128 Palaiseau Cedex (France); Barré-Boscher, Nicole; Borg, Elie; Martin, Julien [Institut de Physique Nucléaire CNRS/IN2P3 UMR 8608 – Université Paris Sud – Université Paris Saclay, F-91406 Orsay Cedex (France)

    2017-03-01

    Nowadays, intense exotic beams are needed in order to study nuclei with very short half-life. To increase the release efficiency of the fission products, all the target characteristics involved must be improved (e.g. chemical composition, dimensions, physicochemical properties such as grain size, porosity, density…). In this article, we study the impact of the target thickness. Released fractions measured from graphite and uranium carbide pellets are presented as well as Monte-Carlo simulations of the Brownian motion.

  2. Surface modification of quartz fibres for dental composites through a sol-gel process.

    Science.gov (United States)

    Wang, Yazi; Wang, Renlin; Habib, Eric; Wang, Ruili; Zhang, Qinghong; Sun, Bin; Zhu, Meifang

    2017-05-01

    In this study, quartz fibres (QFs) surface modification using a sol-gel method was proposed and dental posts reinforced with modified QFs were produced. A silica sol (SS) was prepared using tetraethoxysilane (TEOS) and 3-methacryloxypropyltrimethoxysilane (γ-MPS) as precursors. The amount of γ-MPS in the sol-gel system was varied from 0 to 24wt.% with a constant molar ratio of TEOS, ethanol, deionized water, and HCl. Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and contact angle (CA) measurements were used to characterize the modified QFs, which confirmed that SS had successfully coated the surface of QFs. SEM images showed good interfacial bonding between the modified QFs and the resin matrix. The results of three-point bending tests of the fibre reinforced composite (FRC) posts showed that the QFs modified by SS with 12wt.% γ-MPS presented the best mechanical properties, demonstrating improvements of 108.3% and 89.6% for the flexural strength and flexural modulus, respectively, compared with untreated QFs. Furthermore, the sorption and solubility of the prepared dental posts were also studied by immersing the posts in artificial saliva (AS) for 4weeks, and yielded favourable results. This sol-gel surface modification method promises to resolve interfacial bonding issues of fibres with the resin matrix, and produce FRC posts with excellent properties. Copyright © 2017. Published by Elsevier B.V.

  3. NdFeB thick films prepared by tape casting

    International Nuclear Information System (INIS)

    Pawlowski, B.; Schwarzer, S.; Rahmig, A.; Toepfer, J.

    2003-01-01

    NdFeB films of thickness between 100 and 800 μm were prepared by tape casting of a slurry containing 84-95 wt% of commercial NdFeB powder (MQP-B, -Q and -S). After curing the flexible green tapes at 120 deg. C non-porous magnetic films are obtained. The remanence of the films is in the range of 350-450 mT and the coercivity is between 300 and 800 kA/m depending on the type of MQP powder used. The magnetic properties of the films are discussed in relation to film composition and type of magnetic material. For MEMS applications the thick films are magnetized with a multi-pole stripe pattern with 1 mm pole pitch. The induction at the surface of the films was measured with a Hall probe and compared to theoretical calculations. The results indicate that the films are completely magnetized regardless of the film thickness. Tape-casted NdFeB thick films are promising candidates for applications in micro-systems or actuators. Miniaturization of the magnet components is one of the key issues in the development of electromagnetic micro-systems, thus creating a need for replacement of small sintered magnets by magnetic thick film components. Other applications include encoders

  4. Influence of polymerization time and depth of cure of resin composites determined by Vickers hardness

    Directory of Open Access Journals (Sweden)

    Marco Lombardini

    2012-01-01

    Conclusion: Among the materials tested, the nanofilled and the nanohybrid resin composites were rather insensible to thickness variations. Miicrohybrid composites, instead, had features different from one another.

  5. Studies on Gas Sensing Performance of Cr-doped Indium Oxide Thick Film Sensors

    Directory of Open Access Journals (Sweden)

    D. N. Chavan

    2011-02-01

    Full Text Available A series of In1-xCrxO3 composites, with x ranging from 0.01 to 0.5wt% were prepared by mechanochemically starting from InCl3 and CrO3. Structural and micro structural characteristics of the sample were investigated by XRD, SEM with EDAX. Thick films of pure Indium Oxide and composites were prepared by standard screen printing technique. The gas sensitivity of these thick films was tested for various gases. The pure Indium Oxide thick film (x=0 shows maximum sensitivity to ethanol vapour (80 ppm at 350 oC, but composite-A (x=0.01 thick film shows maximum sensitivity to H2S gas (40 ppm at 250 oC, composite-B (x=0.1 thick film shows higher sensitivity to NH3 gas (80 ppm at 250 oC and composite-C (x=0.5 thick film shows maximum sensitivity to Cl2 gas (80 ppm at 350 oC. A systematic study of gas sensing performance of the sensors indicates the key role played by concentration variation of Cr doped species. The sensitivity, selectivity and recovery time of the sensor were measured and presented.

  6. Thickly Syndetical Sensitivity of Topological Dynamical System

    Directory of Open Access Journals (Sweden)

    Heng Liu

    2014-01-01

    Full Text Available Consider the surjective continuous map f:X→X, where X is a compact metric space. In this paper we give several stronger versions of sensitivity, such as thick sensitivity, syndetic sensitivity, thickly syndetic sensitivity, and strong sensitivity. We establish the following. (1 If (X,f is minimal and sensitive, then (X,f is syndetically sensitive. (2 Weak mixing implies thick sensitivity. (3 If (X,f is minimal and weakly mixing, then it is thickly syndetically sensitive. (4 If (X,f is a nonminimal M-system, then it is thickly syndetically sensitive. Devaney chaos implies thickly periodic sensitivity. (5 We give a syndetically sensitive system which is not thickly sensitive. (6 We give thickly syndetically sensitive examples but not cofinitely sensitive ones.

  7. three dimensional photoelastic investigations on thick rectangular

    African Journals Online (AJOL)

    user

    1983-09-01

    Sep 1, 1983 ... Thick rectangular plates are investigated by means of three-dimensional photoelasticity ... a thin plate theory and a higher order thick plate theory. 1. ..... number of fringes lest the accuracy of the results will be considerably.

  8. Non-contact radiation thickness gauge

    International Nuclear Information System (INIS)

    Tsujii, T.; Okino, T.

    1983-01-01

    A noncontact thickness gauge system for measuring the thickness of a material comprising a source of radiation, a detector for detecting the amount of radiation transmitted through the material which is a function of the absorptance and thickness of the material, a memory for storing the output signals of the detector and curve-defining parameters for a plurality of quadratic calibration curves which correspond to respective thickness ranges, and a processor for processing the signals and curve defining parameters to determine the thickness of the material. Measurements are made after precalibration to obtain calibration curves and these are stored in the memory, providing signals representative of a nominal thickness and an alloy compensation coefficient for the material. The calibration curve corresponding to a particular thickness range is selected and the curve compensated for drift; the material is inserted into the radiation path and the detector output signal processed with the compensated calibration curve to determine the thickness of the material. (author)

  9. Micromechanical Models of Mechanical Response of High Performance Fibre Reinforced Cement Composites

    DEFF Research Database (Denmark)

    Li, V. C.; Mihashi, H.; Alwan, J.

    1996-01-01

    generation of FRC with high performance and economical viability, is in sight. However, utilization of micromechanical models for a more comprehensive set of important HPFRCC properties awaits further investigations into fundamental mechanisms governing composite properties, as well as intergrative efforts......The state-of-the-art in micromechanical modeling of the mechanical response of HPFRCC is reviewed. Much advances in modeling has been made over the last decade to the point that certain properties of composites can be carefully designed using the models as analytic tools. As a result, a new...... across responses to different load types. Further, micromechanical models for HPFRCC behavior under complex loading histories, including those in fracture, fatigue and multuaxial loading are urgently needed in order to optimize HPFRCC microstrcuctures and enable predictions of such material in structures...

  10. Statistics of Microstructure, Peak Stress and Interface Damage in Fiber Reinforced Composites

    DEFF Research Database (Denmark)

    Kushch, Volodymyr I.; Shmegera, Sergii V.; Mishnaevsky, Leon

    2009-01-01

    This paper addresses an effect of the fiber arrangement and interactions on the peak interface stress statistics in a fiber reinforced composite material (FRC). The method we apply combines the multipole expansion technique with the representative unit cell model of composite bulk, which is able...... to simulate both the uniform and clustered random fiber arrangements. By averaging over a number of numerical tests, the empirical probability functions have been obtained for the nearest neighbor distance and the peak interface stress. It is shown that the considered statistical parameters are rather...... sensitive to the fiber arrangement, particularly cluster formation. An explicit correspondence between them has been established and an analytical formula linking the microstructure and peak stress statistics in FRCs has been suggested. Application of the statistical theory of extreme values to the local...

  11. Autonomous Sea-Ice Thickness Survey

    Science.gov (United States)

    2016-06-01

    the conductivity of an infinitely thick slab of sea ice. Ice thickness, Hice, is then obtained by subtracting the height of the ...Thickness Survey of Sea Ice Runway” ERDC/CRREL SR-16-4 ii Abstract We conducted an autonomous survey of sea -ice thickness using the Polar rover Yeti...efficiency relative to manual surveys routinely con- ducted to assess the safety of roads and runways constructed on the sea ice. Yeti executed the

  12. doped ZnO thick film resistors

    Indian Academy of Sciences (India)

    The characterization and ethanol gas sensing properties of pure and doped ZnO thick films were investigated. Thick films of pure zinc oxide were prepared by the screen printing technique. Pure zinc oxide was almost insensitive to ethanol. Thick films of Al2O3 (1 wt%) doped ZnO were observed to be highly sensitive to ...

  13. Macular thickness and volume in the elderly

    DEFF Research Database (Denmark)

    Subhi, Yousif; Forshaw, Thomas; Sørensen, Torben Lykke

    2016-01-01

    manifests in the macula of the elderly focusing on clinical relevant measures that are thicknesses and volumes of different macular areas. Ageing seems to increase center point foveal thickness. Ageing does not seem to change the center subfield thickness significantly. Ageing decreases the inner and outer...

  14. Dielectrophoretic capture of low abundance cell population using thick electrodes.

    Science.gov (United States)

    Marchalot, Julien; Chateaux, Jean-François; Faivre, Magalie; Mertani, Hichem C; Ferrigno, Rosaria; Deman, Anne-Laure

    2015-09-01

    Enrichment of rare cell populations such as Circulating Tumor Cells (CTCs) is a critical step before performing analysis. This paper presents a polymeric microfluidic device with integrated thick Carbon-PolyDimethylSiloxane composite (C-PDMS) electrodes designed to carry out dielectrophoretic (DEP) trapping of low abundance biological cells. Such conductive composite material presents advantages over metallic structures. Indeed, as it combines properties of both the matrix and doping particles, C-PDMS allows the easy and fast integration of conductive microstructures using a soft-lithography approach while preserving O2 plasma bonding properties of PDMS substrate and avoiding a cumbersome alignment procedure. Here, we first performed numerical simulations to demonstrate the advantage of such thick C-PDMS electrodes over a coplanar electrode configuration. It is well established that dielectrophoretic force ([Formula: see text]) decreases quickly as the distance from the electrode surface increases resulting in coplanar configuration to a low trapping efficiency at high flow rate. Here, we showed quantitatively that by using electrodes as thick as a microchannel height, it is possible to extend the DEP force influence in the whole volume of the channel compared to coplanar electrode configuration and maintaining high trapping efficiency while increasing the throughput. This model was then used to numerically optimize a thick C-PDMS electrode configuration in terms of trapping efficiency. Then, optimized microfluidic configurations were fabricated and tested at various flow rates for the trapping of MDA-MB-231 breast cancer cell line. We reached trapping efficiencies of 97% at 20 μl/h and 78.7% at 80 μl/h, for 100 μm thick electrodes. Finally, we applied our device to the separation and localized trapping of CTCs (MDA-MB-231) from a red blood cells sample (concentration ratio of 1:10).

  15. Effect of length to thickness ratio on free vibration analysis of thick fiber reinforced plastic skew cross-ply laminate with circular cutout

    Science.gov (United States)

    Srividya, K.; Reddy, Ch. Kishore; Sumanth, Ch. Mohan; Krishnaiah, P. Gopala; Kishan, V. Mallikharjuna

    2018-04-01

    The present investigation deals with the free vibration analysis of a thick four-layered symmetric cross-ply skew laminated composite plate with a circular cutout. Three dimensional finite element models (FEM) which use the elasticity theory for the determination of stiffness matrices are modeled in ANSYS software to evaluate first five natural frequencies of the laminate. The variations of the first five natural frequencies with respect to length to thickness ratio (S) for different diameter to length ratios (d/l) are presented. It is observed that, the natural frequencies decreases with increase of thickness ratio(S).

  16. Reaction products between Bi-Sr-Ca-Cu-oxide thick films and alumina substrates

    International Nuclear Information System (INIS)

    Alarco, J.A.; Ilushechkin, A.; Yamashita, T.; Bhargava, A.; Barry, J.; Mackinnon, I.D.R.

    1997-01-01

    The structure and composition of reaction products between Bi-Sr-Ca-Cu-oxide (BSCCO) thick films and alumina substrates have been characterized using a combination of electron diffraction, scanning electron microscopy and energy dispersive X-ray spectrometry (EDX). Sr and Ca are found to be the most reactive cations with alumina. Sr 4 Al 6 O 12 SO 4 is formed between the alumina substrates and BSCCO thick films prepared from paste with composition close to Bi-2212 (and Bi-2212+10 wt.% Ag). For paste with composition close to Bi(Pb)-2223 +20 wt.% Ag, a new phase with f.c.c. structure, lattice parameter about a=24.5 A and approximate composition Al 3 Sr 2 CaBi 2 CuO x has been identified in the interface region. Understanding and control of these reactions is essential for growth of high quality BSCCO thick films on alumina. (orig.)

  17. Realization of FRC interior and exterior furniture

    Science.gov (United States)

    Šonka, Š.; Frantová, M.; Štemberk, P.; Havrda, J.; Janouch, P.

    2017-09-01

    This article deals with the implementation of fibre reinforced concrete for interior and exterior furniture. The use of fibre reinforced concrete for non-traditional and small structures brings some specifics in design and realization. These are, in particular, the design of a suitable mixture, the choice of the shape of the structure in relation to the technological possibilities of realization, the static effects and finally the actual production of the element.

  18. A program of FRC theory research

    International Nuclear Information System (INIS)

    Krall, N.A.

    1990-01-01

    At the request of the Office of Fusion Energy, a group of experts was convened on February 6--8, 1990. This group met to assess the world data base on Reversed Field Pinch (RFP) physics, and, further, to assess the role of the ZTH experiment in providing reactor relevant physics understanding for that confinement geometry. This group met, analyzed some of the relevant literature, and heard extensive presentations on the physics of the RFP and the plans for the ZTH and RFX devices. The conclusions of this group of experts are contained in this report

  19. Spatial Evolution of the Thickness Variations over a CFRP Laminated Structure

    Science.gov (United States)

    Davila, Yves; Crouzeix, Laurent; Douchin, Bernard; Collombet, Francis; Grunevald, Yves-Henri

    2017-10-01

    Ply thickness is one of the main drivers of the structural performance of a composite part. For stress analysis calculations (e.g., finite element analysis), composite plies are commonly considered to have a constant thickness compared to the reality (coefficients of variation up to 9% of the mean ply thickness). Unless this variability is taken into account reliable property predictions cannot be made. A modelling approach of such variations is proposed using parameters obtained from a 16-ply quasi-isotropic CFRP plate cured in an autoclave. A discrete Fourier transform algorithm is used to analyse the frequency response of the observed ply and plate thickness profiles. The model inputs, obtained by a mathematical representation of the ply thickness profiles, permit the generation of a representative stratification considering the spatial continuity of the thickness variations that are in good agreement with the real ply profiles spread over the composite part. A residual deformation FE model of the composite plate is used to illustrate the feasibility of the approach.

  20. Superconducting composites materials. Materiaux composites supraconducteurs

    Energy Technology Data Exchange (ETDEWEB)

    Kerjouan, P; Boterel, F; Lostec, J; Bertot, J P; Haussonne, J M [Centre National d' Etudes des Telecommunications (CNET), 22 - Lannion (FR)

    1991-11-01

    The new superconductor materials with a high critical current own a large importance as well in the electronic components or in the electrotechnical devices fields. The deposit of such materials with the thick films technology is to be more and more developed in the years to come. Therefore, we tried to realize such thick films screen printed on alumina, and composed mainly of the YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} material. We first realized a composite material glass/YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}, by analogy with the classical screen-printed inks where the glass ensures the bonding with the substrate. We thus realized different materials by using some different classes of glass. These materials owned a superconducting transition close to the one of the pure YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} material. We made a slurry with the most significant composite materials and binders, and screen-printed them on an alumina substrate preliminary or not coated with a diffusion barrier layer. After firing, we studied the thick films adhesion, the alumina/glass/composite material interfaces, and their superconducting properties. 8 refs.; 14 figs.; 9 tabs.

  1. Three-dimensional primate molar enamel thickness.

    Science.gov (United States)

    Olejniczak, Anthony J; Tafforeau, Paul; Feeney, Robin N M; Martin, Lawrence B

    2008-02-01

    Molar enamel thickness has played an important role in the taxonomic, phylogenetic, and dietary assessments of fossil primate teeth for nearly 90 years. Despite the frequency with which enamel thickness is discussed in paleoanthropological discourse, methods used to attain information about enamel thickness are destructive and record information from only a single plane of section. Such semidestructive planar methods limit sample sizes and ignore dimensional data that may be culled from the entire length of a tooth. In light of recently developed techniques to investigate enamel thickness in 3D and the frequent use of enamel thickness in dietary and phylogenetic interpretations of living and fossil primates, the study presented here aims to produce and make available to other researchers a database of 3D enamel thickness measurements of primate molars (n=182 molars). The 3D enamel thickness measurements reported here generally agree with 2D studies. Hominoids show a broad range of relative enamel thicknesses, and cercopithecoids have relatively thicker enamel than ceboids, which in turn have relatively thicker enamel than strepsirrhine primates, on average. Past studies performed using 2D sections appear to have accurately diagnosed the 3D relative enamel thickness condition in great apes and humans: Gorilla has the relatively thinnest enamel, Pan has relatively thinner enamel than Pongo, and Homo has the relatively thickest enamel. Although the data set presented here has some taxonomic gaps, it may serve as a useful reference for researchers investigating enamel thickness in fossil taxa and studies of primate gnathic biology.

  2. Characteristics of the thick, compound refractive lens

    International Nuclear Information System (INIS)

    Pantell, Richard H.; Feinstein, Joseph; Beguiristain, H. Raul; Piestrup, Melvin A.; Gary, Charles K.; Cremer, Jay T.

    2003-01-01

    A compound refractive lens (CRL), consisting of a series of N closely spaced lens elements each of which contributes a small fraction of the total focusing, can be used to focus x rays or neutrons. The thickness of a CRL can be comparable to its focal length, whereupon a thick-lens analysis must be performed. In contrast with the conventional optical lens, where the ray inside the lens follows a straight line, the ray inside the CRL is continually changing direction because of the multiple refracting surfaces. Thus the matrix representation for the thick CRL is quite different from that for the thick optical lens. Principal planes can be defined such that the thick-lens matrix can be converted to that of a thin lens. For a thick lens the focal length is greater than for a thin lens with the same lens curvature, but this lengthening effect is less for the CRL than for the conventional optical lens

  3. Improving the performance of IPMCs with a gradient in thickness

    International Nuclear Information System (INIS)

    Zhao, Yang; Xu, Bing; Zheng, Gaofeng; Zheng, Jianyi; Qiu, Xiaochun; Zhuang, Mingfeng; Sun, Daoheng

    2013-01-01

    An ionic polymer metal composite (IPMC) is a kind of electro-active polymer. Due to the properties of low driving voltage, large deformation, flexibility and lightness, it is becoming one of the more popular from a diversity of smart materials. In this study, a novel structure of Nafion ® film is proposed to improve the performance of an IPMC. IPMC samples with a gradient structure in thickness are fabricated and their performance is investigated to confirm the validity of the gradient structure. The deformation displacement and the blocking force are compared under AC and DC voltage by experiments. The results indicate that the structure of gradient in thickness would improve the performance both in deformation displacement and blocking force. (paper)

  4. Graph Treewidth and Geometric Thickness Parameters

    OpenAIRE

    Dujmović, Vida; Wood, David R.

    2005-01-01

    Consider a drawing of a graph $G$ in the plane such that crossing edges are coloured differently. The minimum number of colours, taken over all drawings of $G$, is the classical graph parameter "thickness". By restricting the edges to be straight, we obtain the "geometric thickness". By further restricting the vertices to be in convex position, we obtain the "book thickness". This paper studies the relationship between these parameters and treewidth. Our first main result states that for grap...

  5. Localizing gravity on exotic thick 3-branes

    International Nuclear Information System (INIS)

    Castillo-Felisola, Oscar; Melfo, Alejandra; Pantoja, Nelson; Ramirez, Alba

    2004-01-01

    We consider localization of gravity on thick branes with a nontrivial structure. Double walls that generalize the thick Randall-Sundrum solution, and asymmetric walls that arise from a Z 2 symmetric scalar potential, are considered. We present a new asymmetric solution: a thick brane interpolating between two AdS 5 spacetimes with different cosmological constants, which can be derived from a 'fake supergravity' superpotential, and show that it is possible to confine gravity on such branes

  6. Does cement mantle thickness really matter?

    OpenAIRE

    Caruana, J.

    2008-01-01

    The thickness of the cement mantle around the femoral component of total hip replacements is a contributing factor to aseptic loosening and revision. Nevertheless, various designs of stems and surgical tooling lead to cement mantles of differing thicknesses. This thesis is concerned with variability in cement thickness around the Stanmore Hip, due to surgical approach, broach size and stem orientation, and its effects on stress and cracking in the cement. The extent to which cement mantle thi...

  7. Radiation transmission pipe thickness measurement system

    International Nuclear Information System (INIS)

    Higashi, Yasuhiko

    2010-01-01

    Fuji Electric Systems can be measured from the outer insulation of the transmission Characteristics and radiation detection equipment had been developed that can measure pipe wall thinning in plant and running, the recruitment of another three-beam calculation method by pipe thickness measurement system was developed to measure the thickness of the pipe side. This equipment has been possible to measure the thickness of the circumferential profile of the pipe attachment by adopting automatic rotation. (author)

  8. Influence of Laser Activated Irrigation with Erbium Lasers on Bond Strength of Inidividually Formed Fiber Reinforced Composite Posts to Root Canal Dentin

    Directory of Open Access Journals (Sweden)

    Ivana Miletić

    2016-01-01

    Full Text Available Objective: The aim of this in vitro study was to investigate the effect of laser activated irrigation (LAI using two erbium lasers on bond strength of individually formed fiber-reinforced composite (FRC posts to root canal dentin. Materials and methods: Twenty-seven single-rooted human teeth were endodontically treated and after post space preparation divided into three groups (n=9 per group, according to the pre-treatment of post space preparation: 1 Conventional syringe irrigation (CSI and saline; 2 Er.YAG photon-induced photoacoustic streaming (PIPS technique and saline; 3 Er,Cr:YSGG activated irrigation with RFT2 tip. Two specimens from each group were used for SEM analysis. The remaining specimens (n=7 per group received individually formed FRC post, everStick POST, luted with self-adhesive cement, G-CEM LinkAce. After cementation, the roots were perpendicularly sectioned into 1 mm thin sections and a push-out test was carried out (0.5 mm/min. The data were calculated as megapascals and were log transformed and statistically analysed using one-way ANOVA at the level of significance set at 5%. Results: In the control group, the smear layer was still present. In the Er:YAG group, the smear layer was removed. In the Er,Cr:YSGG group, the smear layer was partially removed. The Er,Cr:YSGG group achieved the highest bond strength values, followed by the control group and then the Er:YAG group, but no statistically significant difference was found in bond strength values in the tested group of post space pretreatment (p=0.564. Conclusions: LAI using two erbium lasers, with PIPS or RFT2 tip, did not affect the bond strength of individually formed FRC posts to root canal dentin.

  9. Card controlled beta backscatter thickness measuring instrument

    International Nuclear Information System (INIS)

    Schlesinger, J.

    1978-01-01

    An improved beta backscatter instrument for the nondestructive measurement of the thickness of thin coatings on a substrate is described. Included therein is the utilization of a bank of memory stored data representative of isotope, substrate, coating material and thickness range characteristics in association with a control card having predetermined indicia thereon selectively representative of a particular isotope, substrate material, coating material and thickness range for conditioning electronic circuit means by memory stored data selected in accord with the predetermined indicia on a control card for converting backscattered beta particle counts into indicia of coating thickness

  10. Uncertainties in thick-target PIXE analysis

    International Nuclear Information System (INIS)

    Campbell, J.L.; Cookson, J.A.; Paul, H.

    1983-01-01

    Thick-target PIXE analysis insolves uncertainties arising from the calculation of thick-target X-ray production in addition to the usual PIXE uncertainties. The calculation demands knowledge of ionization cross-sections, stopping powers and photon attenuation coefficients. Information on these is reviewed critically and a computational method is used to estimate the uncertainties transmitted from this data base into results of thick-target PIXE analyses with reference to particular specimen types using beams of 2-3 MeV protons. A detailed assessment of the accuracy of thick-target PIXE is presented. (orig.)

  11. Visceral fat is more important than peripheral fat for endometrial thickness and bone mass in healthy postmenopausal women

    DEFF Research Database (Denmark)

    Warming, Lise; Ravn, Pernille; Christiansen, Claus

    2003-01-01

    as double-layer thickness. Body composition was measured by dual energy x-ray absorptiometry, which divides the body into fat mass, lean mass, and bone mass, both for the total body and regional body compartments. An abdominal region was inserted manually. Statistics were Pearson correlations and analysis...... of variance. RESULTS: Endometrial thickness and total body bone mass were correlated, respectively, to body mass index (r = 0.14, P ... correlate with increased endometrial thickness and bone mass....

  12. Contribution to the study of slab thickness

    International Nuclear Information System (INIS)

    Moraitis, G.A.; Rorris, G.P.

    1978-01-01

    A method is proposed for calculating the time-independent values of the equivalent slab thickness of the ionosphere, defined as the ratio of the total electron content to the corresponding maximum electron density of the F region. Periodic variations of slab thickness are studied and are correlated to relative changes in exospheric temperature, deduced from the OGO-6 model

  13. Eggshell thickness in mourning dove populations

    Science.gov (United States)

    Kreitzer, J.F.

    1971-01-01

    Eggs (n = 452) of the mourning dove (Zenaidura macroura) were collected from 9 states in 1969 and 11 states in 1970, and shell thickness was compared with that of eggs (n = 97) collected from 24 states during the years 1861 to 1935. Mean shell thickness did not differ significantly in the test groups.

  14. Applications of precision ultrasonic thickness gauging

    International Nuclear Information System (INIS)

    Fowler, K.A.; Elfbaum, G.M.; Husarek, V.; Castel, J.G.

    1976-01-01

    Pulse-echo ultrasonic thickness gauging is now recognized as an accurate method of measuring thickness of a product from one side when the velocity of ultrasound in the material is known. The advantages and present limitation of this gauging technique are presented, together with several applications of industrial interest [fr

  15. Skull thickness in patients with clefts

    DEFF Research Database (Denmark)

    Arntsen, T; Kjaer, I; Sonnesen, L

    2010-01-01

    The purpose was to analyze skull thickness in incomplete cleft lip (CL), cleft palate (CP), and combined cleft lip and palate (UCLP).......The purpose was to analyze skull thickness in incomplete cleft lip (CL), cleft palate (CP), and combined cleft lip and palate (UCLP)....

  16. Effects of thickness on the statistical properties of the Barkhausen noise in amorphous films

    Energy Technology Data Exchange (ETDEWEB)

    Santi, L. [Departamento de Fisica, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS (Brazil); Bohn, F. [Departamento de Fisica, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS (Brazil); Viegas, A.D.C. [Departamento de Fisica, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS (Brazil); Durin, G. [Istituto Elettrotecnico Nazionale Galileo Ferraris, Turin (Italy); Magni, A. [Istituto Elettrotecnico Nazionale Galileo Ferraris, Turin (Italy); Bonin, R. [Istituto Elettrotecnico Nazionale Galileo Ferraris, Turin (Italy); Zapperi, S. [Istituto dei Sistemi Complessi-CNR, Roma (Italy); Sommer, R.L. [Centro Brasileiro de Pesquisas Fisicas, 22290-180, Rio de Janeiro, RJ (Brazil)]. E-mail: sommer@cbpf.br

    2006-10-01

    The statistical properties of the Barkhausen noise (BN) in thin amorphous films are studied as a function of both the nominal composition and the thickness. BN was observed in single films with nominal compositions Fe{sub 73.5}Cu{sub 1}Nb{sub 3}Si{sub 22.5-x}B{sub x} (with x=4 and 9) in the thickness range 20nm-5{mu}m. The distributions of Barkhausen jump sizes and duration times were obtained and fitted to power laws with critical exponents {tau}=1.25+/-0.05 and {alpha}=1.60+/-0.05, respectively.

  17. Self-compensating x-ray or γ-ray thickness gauge

    International Nuclear Information System (INIS)

    Allport, J.J.

    1977-01-01

    A gauge is described for determining the mass per unit area, or alternatively the thickness of sheet material by measuring the attenuation, as well as backscatter, of an x-ray beam or the like, while continuously taking into account deviations and changes in localized material composition, insofar as these have an effect on the transmission coefficient of the beam. Electrical signals representing these deviations are combined with calibration data for given material nominal properties, i.e., nominal composition. The resultant and output signal represents the mass per unit area or thickness

  18. Effects of thickness on the statistical properties of the Barkhausen noise in amorphous films

    International Nuclear Information System (INIS)

    Santi, L.; Bohn, F.; Viegas, A.D.C.; Durin, G.; Magni, A.; Bonin, R.; Zapperi, S.; Sommer, R.L.

    2006-01-01

    The statistical properties of the Barkhausen noise (BN) in thin amorphous films are studied as a function of both the nominal composition and the thickness. BN was observed in single films with nominal compositions Fe 73.5 Cu 1 Nb 3 Si 22.5-x B x (with x=4 and 9) in the thickness range 20nm-5μm. The distributions of Barkhausen jump sizes and duration times were obtained and fitted to power laws with critical exponents τ=1.25+/-0.05 and α=1.60+/-0.05, respectively

  19. Magnetic property zonation in a thick lava flow

    Science.gov (United States)

    Audunsson, Haraldur; Levi, Shaul; Hodges, Floyd

    1992-04-01

    Intraflow structures and magmatic evolution in an extensive and thick (30-60 m) basaltic lava flow are examined on the basis of grain size and composition-dependent magnetic properties of titanomagnetite materials. Microprobe data indicate that the intraflow oxidation state Fe(3+)/Fe(2+) of the initially precipitated primary titanomagnetites increases with falling equilibrium temperature from the flow margins to a maximum near the center, the position of lowest equilibrium temperature. In contrast, Curie temperature measurements indicate that titanomagnetite oxidation increases with height in the flow. Modification of the initially symmetric equilibrium titanomagnetite compositions was caused by subsolidus high-temperature oxidation possibly due to hydrogen loss produced by dissociation of magmatic water, as well as unknown contributions of circulating air and percolating water from above. The titanomagnetites of the basal layer of the flow remain essentially unaltered.

  20. Usage of neural network to predict aluminium oxide layer thickness.

    Science.gov (United States)

    Michal, Peter; Vagaská, Alena; Gombár, Miroslav; Kmec, Ján; Spišák, Emil; Kučerka, Daniel

    2015-01-01

    This paper shows an influence of chemical composition of used electrolyte, such as amount of sulphuric acid in electrolyte, amount of aluminium cations in electrolyte and amount of oxalic acid in electrolyte, and operating parameters of process of anodic oxidation of aluminium such as the temperature of electrolyte, anodizing time, and voltage applied during anodizing process. The paper shows the influence of those parameters on the resulting thickness of aluminium oxide layer. The impact of these variables is shown by using central composite design of experiment for six factors (amount of sulphuric acid, amount of oxalic acid, amount of aluminium cations, electrolyte temperature, anodizing time, and applied voltage) and by usage of the cubic neural unit with Levenberg-Marquardt algorithm during the results evaluation. The paper also deals with current densities of 1 A · dm(-2) and 3 A · dm(-2) for creating aluminium oxide layer.

  1. Usage of Neural Network to Predict Aluminium Oxide Layer Thickness

    Directory of Open Access Journals (Sweden)

    Peter Michal

    2015-01-01

    Full Text Available This paper shows an influence of chemical composition of used electrolyte, such as amount of sulphuric acid in electrolyte, amount of aluminium cations in electrolyte and amount of oxalic acid in electrolyte, and operating parameters of process of anodic oxidation of aluminium such as the temperature of electrolyte, anodizing time, and voltage applied during anodizing process. The paper shows the influence of those parameters on the resulting thickness of aluminium oxide layer. The impact of these variables is shown by using central composite design of experiment for six factors (amount of sulphuric acid, amount of oxalic acid, amount of aluminium cations, electrolyte temperature, anodizing time, and applied voltage and by usage of the cubic neural unit with Levenberg-Marquardt algorithm during the results evaluation. The paper also deals with current densities of 1 A·dm−2 and 3 A·dm−2 for creating aluminium oxide layer.

  2. Mechanical properties and material characterization of polysialate structural composites

    Science.gov (United States)

    Foden, Andrew James

    One of the major concerns in using Fiber Reinforced Composites in applications that are subjected to fire is their resistance to high temperature. Some of the fabrics used in FRC, such as carbon, are fire resistant. However, almost all the resins used cannot withstand temperatures higher than 200°C. This dissertation deals with the development and use of a potassium aluminosilicate (GEOPOLYMER) resin that is inorganic and can sustain more than 1000°C. The results presented include the mechanical properties of the unreinforced polysialate matrix in tension, flexure, and compression as well as the strain capacities and surface energy. The mechanical properties of the matrix reinforced with several different fabrics were obtained in flexure, tension, compression and shear. The strength and stiffness of the composite was evaluated for each loading condition. Tests were conducted on unexposed samples as well as samples exposed to temperatures from 200 to 1000°C. Fatigue properties were determined using flexural loading. A study of the effect of several processing variables on the properties of the composite was undertaken to determine the optimum procedure for manufacturing composite plates. The processing variables studied were the curing temperature and pressure, and the post cure drying time required to remove any residual water. The optimum manufacturing conditions were determined using the void content, density, fiber volume fraction, and flexural strength. Analytical models are presented based on both micro and macro mechanical analysis of the composite. Classic laminate theory is used to evaluate the state of the composite as it is being loaded to determine the failure mechanisms. Several failure criteria theories are considered. The analysis is then used to explain the mechanical behavior of the composite that was observed during the experimental study.

  3. Study on the ionization chamber for thickness measurement

    International Nuclear Information System (INIS)

    Xue Shili; Miao Qiangwen

    1988-01-01

    The principle, construction and performances of ionization chambers for measuring the thickness of metal and nonmetal materials are introduced. With them the thickness of thin materials (thickness ranging from 10 to 6000 g/m 2 ), the surface layer thickness of composed materials and the thickness of steel plate (thickness ranging from 0 to 32 kg/m 2 ) are measured effectively

  4. Preparation and characterization of thick metastable sputter deposits

    International Nuclear Information System (INIS)

    Allen, R.P.; Dahlgren, S.D.; Merz, M.D.

    1975-01-01

    High-rate dc supported-discharge sputtering techniques were developed and used to prepare 0.1 mm to 5.0 mm-thick deposits of a variety of metastable materials including amorphous alloys representing more than 15 different rare-earth-transition metal systems and a wide range of compositions and deposition conditions. The ability to prepare thick, homogeneous deposits has made it possible for the first time to investigate the structure, properties, and annealing behavior of these unique sputtered alloys using neutron diffraction, ultrasonic, and other experimental techniques that are difficult or impractical for thin films. More importantly, these characterization studies show that the structure and properties of the massive sputter deposits are independent of thickness and can be reproduced from deposit to deposit. Other advantages and applications of this metastable materials preparation technique include the possibility of varying structure and properties by control of the deposition parameters and the ability to deposit even reactive alloys with a very low impurity content

  5. Mechanical Properties of Additively Manufactured Thick Honeycombs

    Directory of Open Access Journals (Sweden)

    Reza Hedayati

    2016-07-01

    Full Text Available Honeycombs resemble the structure of a number of natural and biological materials such as cancellous bone, wood, and cork. Thick honeycomb could be also used for energy absorption applications. Moreover, studying the mechanical behavior of honeycombs under in-plane loading could help understanding the mechanical behavior of more complex 3D tessellated structures such as porous biomaterials. In this paper, we study the mechanical behavior of thick honeycombs made using additive manufacturing techniques that allow for fabrication of honeycombs with arbitrary and precisely controlled thickness. Thick honeycombs with different wall thicknesses were produced from polylactic acid (PLA using fused deposition modelling, i.e., an additive manufacturing technique. The samples were mechanically tested in-plane under compression to determine their mechanical properties. We also obtained exact analytical solutions for the stiffness matrix of thick hexagonal honeycombs using both Euler-Bernoulli and Timoshenko beam theories. The stiffness matrix was then used to derive analytical relationships that describe the elastic modulus, yield stress, and Poisson’s ratio of thick honeycombs. Finite element models were also built for computational analysis of the mechanical behavior of thick honeycombs under compression. The mechanical properties obtained using our analytical relationships were compared with experimental observations and computational results as well as with analytical solutions available in the literature. It was found that the analytical solutions presented here are in good agreement with experimental and computational results even for very thick honeycombs, whereas the analytical solutions available in the literature show a large deviation from experimental observation, computational results, and our analytical solutions.

  6. Film thickness determination by grazing incidence diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Battiston, G A; Gerbasi, R [CNR, Padua (Italy). Istituto di Chimica e Tecnologie Inorganiche e dei Materiali Avanzati

    1996-09-01

    Thin films deposited via MOCVD (Metal Organic Chemical Vapour Deposition) are layers in the thickness range of a few manometers to about ten micrometers. An understanding of the physics and chemistry of films is necessary for a better comprehension of the phenomena involved in the film deposition procedure and its optimisation. Together with the crystalline phase a parameter that must be determined is the thickness of the layer. In this work the authors present a method for the measurement of the film thickness. This procedure, based on diffraction intensity absorption of the X-rays, both incident and diffracted in passing through the layers, resulted quite simple, rapid and non-destructive.

  7. Residual stress analysis in thick uranium films

    International Nuclear Information System (INIS)

    Hodge, A.M.; Foreman, R.J.; Gallegos, G.F.

    2005-01-01

    Residual stress analysis was performed on thick, 1-25 μm, depleted uranium (DU) films deposited on an Al substrate by magnetron sputtering. Two distinct characterization techniques were used to measure substrate curvature before and after deposition. Stress evaluation was performed using the Benabdi/Roche equation, which is based on beam theory of a bi-layer material. The residual stress evolution was studied as a function of coating thickness and applied negative bias voltage (0, -200, -300 V). The stresses developed were always compressive; however, increasing the coating thickness and applying a bias voltage presented a trend towards more tensile stresses and thus an overall reduction of residual stresses

  8. Film thickness determination by grazing incidence diffraction

    International Nuclear Information System (INIS)

    Battiston, G. A.; Gerbasi, R.

    1996-01-01

    Thin films deposited via MOCVD (Metal Organic Chemical Vapour Deposition) are layers in the thickness range of a few manometers to about ten micrometers. An understanding of the physics and chemistry of films is necessary for a better comprehension of the phenomena involved in the film deposition procedure and its optimisation. Together with the crystalline phase a parameter that must be determined is the thickness of the layer. In this work the authors present a method for the measurement of the film thickness. This procedure, based on diffraction intensity absorption of the X-rays, both incident and diffracted in passing through the layers, resulted quite simple, rapid and non-destructive

  9. Turbine airfoil with outer wall thickness indicators

    Science.gov (United States)

    Marra, John J; James, Allister W; Merrill, Gary B

    2013-08-06

    A turbine airfoil usable in a turbine engine and including a depth indicator for determining outer wall blade thickness. The airfoil may include an outer wall having a plurality of grooves in the outer surface of the outer wall. The grooves may have a depth that represents a desired outer surface and wall thickness of the outer wall. The material forming an outer surface of the outer wall may be removed to be flush with an innermost point in each groove, thereby reducing the wall thickness and increasing efficiency. The plurality of grooves may be positioned in a radially outer region of the airfoil proximate to the tip.

  10. Superconducting composites materials

    International Nuclear Information System (INIS)

    Kerjouan, P.; Boterel, F.; Lostec, J.; Bertot, J.P.; Haussonne, J.M.

    1991-01-01

    The new superconductor materials with a high critical current own a large importance as well in the electronic components or in the electrotechnical devices fields. The deposit of such materials with the thick films technology is to be more and more developed in the years to come. Therefore, we tried to realize such thick films screen printed on alumina, and composed mainly of the YBa 2 Cu 3 O 7-δ material. We first realized a composite material glass/YBa 2 Cu 3 O 7-δ , by analogy with the classical screen-printed inks where the glass ensures the bonding with the substrate. We thus realized different materials by using some different classes of glass. These materials owned a superconducting transition close to the one of the pure YBa 2 Cu 3 O 7-δ material. We made a slurry with the most significant composite materials and binders, and screen-printed them on an alumina substrate preliminary or not coated with a diffusion barrier layer. After firing, we studied the thick films adhesion, the alumina/glass/composite material interfaces, and their superconducting properties. 8 refs.; 14 figs.; 9 tabs [fr

  11. Through thickness property variations in a thick plate AA7050 friction stir welded joint

    International Nuclear Information System (INIS)

    Canaday, Clinton T.; Moore, Matthew A.; Tang, Wei; Reynolds, A.P.

    2013-01-01

    In this study, moderately thick (32 mm) AA7050 plates were joined by friction stir welding (FSW). Various methods were used to characterize the welded joints, including nugget grain size measurements at different locations through the thickness, micro-hardness indentation through nugget, thermo-mechanically affected zone (TMAZ), and heat affected zone (HAZ) at different cross section heights, and residual stress measurement using the cut compliance method with full thickness and partial thickness specimens. All testing results are consistent with the presence of a strong gradient in peak temperature through the plate thickness during FSW.

  12. Model SH intelligent instrument for thickness measuring

    International Nuclear Information System (INIS)

    Liu Juntao; Jia Weizhuang; Zhao Yunlong

    1995-01-01

    The authors introduce Model SH Intelligent Instrument for thickness measuring by using principle of beta back-scattering and its application range, features, principle of operation, system design, calibration and specifications

  13. Greenland Radar Ice Sheet Thickness Measurements

    Data.gov (United States)

    National Aeronautics and Space Administration — Two 150-MHz coherent radar depth sounders were developed and flown over the Greenland ice sheet to obtain ice thickness measurements in support of PARCA...

  14. Fabrication of thick superconducting films by decantation

    Directory of Open Access Journals (Sweden)

    Julián Betancourt M.

    1991-07-01

    Full Text Available We have found superconducting behavior in thick films fabricated by decantation. In this paper we present the experimental method and results obtained using commercial copper substrates.

  15. APPLIED ORIGAMI. Origami of thick panels.

    Science.gov (United States)

    Chen, Yan; Peng, Rui; You, Zhong

    2015-07-24

    Origami patterns, including the rigid origami patterns in which flat inflexible sheets are joined by creases, are primarily created for zero-thickness sheets. In order to apply them to fold structures such as roofs, solar panels, and space mirrors, for which thickness cannot be disregarded, various methods have been suggested. However, they generally involve adding materials to or offsetting panels away from the idealized sheet without altering the kinematic model used to simulate folding. We develop a comprehensive kinematic synthesis for rigid origami of thick panels that differs from the existing kinematic model but is capable of reproducing motions identical to that of zero-thickness origami. The approach, proven to be effective for typical origami, can be readily applied to fold real engineering structures. Copyright © 2015, American Association for the Advancement of Science.

  16. Russian River Ice Thickness and Duration

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of river ice thickness measurements, and beginning and ending dates for river freeze-up events from fifty stations in northern Russia. The...

  17. Central corneal thickness among glaucoma patients attending ...

    African Journals Online (AJOL)

    AAU_CHS

    ocular pressure measurement and is different among different ethnic population and subtypes of glaucoma. The central corneal thickness of different subtypes of glaucoma at Menelik II Hospital ... Intraocular pressure is a key element in the.

  18. Eddy current technologies for thick metal structures

    International Nuclear Information System (INIS)

    Takagi, Toshiyuki; Endo, Hisashi

    2004-01-01

    One of approach of an eddy current testing (ECT) for thick metal structures is introduced. The detection limit of ECT is capable of enlarging thick more than 10 mm, which is ordinarily about 5 mm, by the design of probe. On the basis of results of numerical analysis, the defect detection in thick and shape is evaluated by the distribution of experimental ECT signals. The problems of ECT for thick metal structures and measures, approach to probe design, the specifications of probe, evaluation of experimental results and defect detection are described. By ECT fast simulator, good slit sharp is simulated in the case of 10 and 20 mm of EDM slit length and 5, 10 and 15 mm of slit height. (S.Y.)

  19. Arctic Sea Ice Freeboard and Thickness

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides measurements of sea ice freeboard and sea ice thickness for the Arctic region. The data were derived from measurements made by from the Ice,...

  20. Electroplated thick-film cobalt platinum permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Oniku, Ololade D.; Qi, Bin; Arnold, David P., E-mail: darnold@ufl.edu

    2016-10-15

    The material and magnetic properties of multi-micron-thick (up to 6 μm) L1{sub 0} CoPt magnetic films electroplated onto silicon substrates are investigated as candidate materials for integration in silicon-based microsystems. The influence of various process conditions on the structure and magnetic properties of electroplated CoPt thick-films is studied in order to better understand the complex process/structure/property relationships associated with the electroplated films. Process variables studied here include different seed layers, electroplating current densities (ranging from 25–200 mA/cm{sup 2}), deposition times (up to 60 min), and post-deposition annealing times and temperatures. Analyses include film morphology, film thickness, composition, surface roughness, grain size, phase volume fractions, and L1{sub 0} ordering parameter. Key correlations are found relating process and structure variations to the extrinsic magnetic properties (remanence, coercivity, squareness, and energy product). Strong hard magnetic properties (B{sub r} ~0.8 T, H{sub ci} ~800 kA/m, squareness close to 0.9, and BH{sub max} of 100 kJ/m{sup 3}) are obtained for films deposited on Si/TiN/Ti/Cu at current densities of 100 mA/cm{sup 2}, pH of 7, and subsequently annealed at 675 °C for 30 min. - Highlights: • CoPt films plated up to 6 μm thick on silicon substrates. • A1 to L1{sub 0} phase transformation by annealing in forming gas. • Various process–structure–property relationships explored. • Key results: B{sub r} ~0.8 T, H{sub ci} ~800 kA/m, squareness 0.9, and BH{sub max} ~100 kJ/m{sup 3}.

  1. Electroplated thick-film cobalt platinum permanent magnets

    International Nuclear Information System (INIS)

    Oniku, Ololade D.; Qi, Bin; Arnold, David P.

    2016-01-01

    The material and magnetic properties of multi-micron-thick (up to 6 μm) L1 0 CoPt magnetic films electroplated onto silicon substrates are investigated as candidate materials for integration in silicon-based microsystems. The influence of various process conditions on the structure and magnetic properties of electroplated CoPt thick-films is studied in order to better understand the complex process/structure/property relationships associated with the electroplated films. Process variables studied here include different seed layers, electroplating current densities (ranging from 25–200 mA/cm 2 ), deposition times (up to 60 min), and post-deposition annealing times and temperatures. Analyses include film morphology, film thickness, composition, surface roughness, grain size, phase volume fractions, and L1 0 ordering parameter. Key correlations are found relating process and structure variations to the extrinsic magnetic properties (remanence, coercivity, squareness, and energy product). Strong hard magnetic properties (B r ~0.8 T, H ci ~800 kA/m, squareness close to 0.9, and BH max of 100 kJ/m 3 ) are obtained for films deposited on Si/TiN/Ti/Cu at current densities of 100 mA/cm 2 , pH of 7, and subsequently annealed at 675 °C for 30 min. - Highlights: • CoPt films plated up to 6 μm thick on silicon substrates. • A1 to L1 0 phase transformation by annealing in forming gas. • Various process–structure–property relationships explored. • Key results: B r ~0.8 T, H ci ~800 kA/m, squareness 0.9, and BH max ~100 kJ/m 3 .

  2. Rifting Thick Lithosphere - Canning Basin, Western Australia

    Science.gov (United States)

    Czarnota, Karol; White, Nicky

    2016-04-01

    The subsidence histories and architecture of most, but not all, rift basins are elegantly explained by extension of ~120 km thick lithosphere followed by thermal re-thickening of the lithospheric mantle to its pre-rift thickness. Although this well-established model underpins most basin analysis, it is unclear whether the model explains the subsidence of rift basins developed over substantially thick lithosphere (as imaged by seismic tomography beneath substantial portions of the continents). The Canning Basin of Western Australia is an example where a rift basin putatively overlies lithosphere ≥180 km thick, imaged using shear wave tomography. Subsidence modelling in this study shows that the entire subsidence history of the account for the observed subsidence, at standard crustal densities, the lithospheric mantle is required to be depleted in density by 50-70 kg m-3, which is in line with estimates derived from modelling rare-earth element concentrations of the ~20 Ma lamproites and global isostatic considerations. Together, these results suggest that thick lithosphere thinned to > 120 km is thermally stable and is not accompanied by post-rift thermal subsidence driven by thermal re-thickening of the lithospheric mantle. Our results show that variations in lithospheric thickness place a fundamental control on basin architecture. The discrepancy between estimates of lithospheric thickness derived from subsidence data for the western Canning Basin and those derived from shear wave tomography suggests that the latter technique currently is limited in its ability to resolve lithospheric thickness variations at horizontal half-wavelength scales of <300 km.

  3. Phase Space Exchange in Thick Wedge Absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, David [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2017-01-01

    The problem of phase space exchange in wedge absorbers with ionization cooling is discussed. The wedge absorber exchanges transverse and longitudinal phase space by introducing a position-dependent energy loss. In this paper we note that the wedges used with ionization cooling are relatively thick, so that single wedges cause relatively large changes in beam phase space. Calculation methods adapted to such “thick wedge” cases are presented, and beam phase-space transformations through such wedges are discussed.

  4. Geologic thickness data: Candidate repository horizons

    International Nuclear Information System (INIS)

    Cross, R.W.; Fairchild, K.R.

    1985-01-01

    This data package contains information on the thickness of the Umtanum, McCoy Canyon, Cohassett, and Rocky Coulee flows and their intraflow structures in 20 boreholes and 2 surface sections in the Pasco Basin. Thickness data are for total flow, flow top, entablature, and colonnade (or just flow top and dense interior in some cases). Summary figures which contain descriptions and footages are included

  5. Preparation of tantalum targets of known thicknesses

    International Nuclear Information System (INIS)

    Alexander, J.R.; Wirth, H.L.

    1985-01-01

    A series of carbon-backed tantalum targets were produced in a heavy ion sputtering system with a Penning ion source. The target thicknesses were then measured using the alpha-ray energy loss method. The resulting tabulated measurements were reproducible and make possible the production of carbon-backed tantalum targets with pre-determined thicknesses ranging from 20 μg/cm 2 to 1 mg/cm 2 . (orig.)

  6. Elastic stability of thick auxetic plates

    International Nuclear Information System (INIS)

    Lim, Teik-Cheng

    2014-01-01

    Auxetic materials and structures exhibit a negative Poisson’s ratio while thick plates encounter shear deformation, which is not accounted for in classical plate theory. This paper investigates the effect of a negative Poisson’s ratio on thick plates that are subjected to buckling loads, taking into consideration the shear deformation using Mindlin plate theory. Using a highly accurate shear correction factor that allows for the effect of Poisson’s ratio, the elastic stability of circular and square plates are evaluated in terms of dimensionless parameters, namely the Mindlin-to-Kirchhoff critical buckling load ratio and Mindlin critical buckling load factors. Results for thick square plates reveal that both parameters increase as the Poisson’s ratio becomes more negative. In the case of thick circular plates, the Mindlin-to-Kirchhoff critical buckling load ratios and the Mindlin critical buckling load factors increase and decrease, respectively, as the Poisson’s ratio becomes more negative. The results obtained herein show that thick auxetic plates behave as thin conventional plates, and therefore suggest that the classical plate theory can be used to evaluate the elastic stability of thick plates if the Poisson’s ratio of the plate material is sufficiently negative. The results also suggest that materials with highly negative Poisson’s ratios are recommended for square plates, but not circular plates, that are subjected to buckling loads. (paper)

  7. Effectiveness of dispersants on thick oil slicks

    International Nuclear Information System (INIS)

    Ross, S.; Belore, R.

    1993-01-01

    Experiments were conducted to determine the relationship between dispersant effectiveness and oil slick thickness, and thereby determine the optimum time for applying dispersant onto spilled oil at sea. Tests were completed at a lab-scale level by varying the three parameters of oil type, dispersant application, and oil thickness. The tests were intended to be comparative only. The primary oils used were Alberta sweet mix blend and Hibernia B-27 crude. The dispersant, Corexit 9527, was applied either premixed with the oil, dropwise in one application, or dropwise in multiple applications to simulate a multi-hit aircraft operation. The apparatus used in the experiment was an oscillating hoop tank, with oil-containing rings used to obtain and maintain uniform slick thickness. The results indicate that the effectiveness potential of a chemical dispersant does not decrease as slick thickness increases. In fact, results of the tests involving Hibernia oil suggest that oils that tend to herd easily would be treated more effectively if dispersant were applied when the oil was relatively thick (1 mm or greater) to avoid herding problems. The oil slicks premixed with dispersant did not disperse well in the thick oil tests, not because of dispersant-oil interaction problems but because of reduced mixing energy. 6 refs., 4 figs., 1 tab

  8. Rapid Measurement of Nanoparticle Thickness Profiles

    International Nuclear Information System (INIS)

    Katz-Boon, Hadas; Rossouw, Chris J.; Dwyer, Christian; Etheridge, Joanne

    2013-01-01

    A method to measure the thickness of a single-crystal nanoparticle in the direction parallel to the incident beam from annular dark field scanning transmission electron microscope (ADF-STEM) images is reported, providing a map of thickness versus position across the nanoparticle—a ‘thickness profile’ image. The method is rapid and hence suitable for surveying large numbers of nanoparticles. The method measures the intensity scattered to a characterised ADF detector and compares this to the incident beam intensity, to obtain a normalized ADF image. The normalised intensity is then converted to thickness via dynamical ADF image simulations. The method is accurate within 10% and the precision is dominated primarily by ‘shot noise’. Merits and limitations of this method are discussed. A method to calibrate the response function of the ADF detector without external equipment is also described, which is applicable to the entire range of gain and background settings. -- Highlights: ► A method is developed to convert ADF-STEM images to ‘thickness profile’ images. ► It is applicable in particles survey, facets determination and discrete tomography. ► A method to calibrate the response of the ADF detector is described. ► The response in analysed across a range of conditions. ► Dynamical ADF image simulations are presented, demonstrating intensity vs. thickness dependence.

  9. Electrical properties of thick-layer piezo resistors based on Bi2Ru2O7

    International Nuclear Information System (INIS)

    Golonka, L.; Tankiewicz, S.

    1997-01-01

    Piezoelectric effect and electrical properties of thick-layer resistors based on Bi 2 Ru 2 O 7 (on ceramic substrate) have been studied. The influence of selected technological parameters (sintering temperature, chemical composition, heat treatment) on system properties has been estimated. 4 refs, 7 figs

  10. Sampling supraglacial debris thickness using terrestrial photogrammetry

    Science.gov (United States)

    Nicholson, Lindsey; Mertes, Jordan

    2017-04-01

    The melt rate of debris-covered ice differs to that of clean ice primarily as a function of debris thickness. The spatial distribution of supraglacial debris thickness must therefore be known in order to understand how it is likely to impact glacier behaviour, and meltwater contribution to local hydrological resources and global sea level rise. However, practical means of determining debris cover thickness remain elusive. In this study we explore the utility of terrestrial photogrammetry to produce high resolution, scaled and texturized digital terrain models of debris cover exposures above ice cliffs as a means of quantifying and characterizing debris thickness. Two Nikon D5000 DSLRs with Tamron 100mm lenses were used to photograph a sample area of the Ngozumpa glacier in the Khumbu Himal of Nepal in April 2016. A Structure from Motion workflow using Agisoft Photoscan software was used to generate a surface models with <10cm resolution. A Trimble Geo7X differential GPS with Zephyr antenna, along with a local base station, was used to precisely measure marked ground control points to scale the photogrammetric surface model. Measurements of debris thickness along the exposed cliffline were made from this scaled model, assuming that the ice surface at the debris-ice boundary is horizontal, and these data are compared to 50 manual point measurements along the same clifftops. We conclude that sufficiently high resolution photogrammetry, with precise scaling information, provides a useful means to determine debris thickness at clifftop exposures. The resolution of the possible measurements depends on image resolution, the accuracy of the ground control points and the computational capacity to generate centimetre scale surface models. Application of such techniques to sufficiently high resolution imagery from UAV-borne cameras may offer a powerful means of determining debris thickness distribution patterns over debris covered glacier termini.

  11. Choroidal thickness in traumatic optic neuropathy.

    Science.gov (United States)

    Lee, Ju-Yeun; Eo, Doo-Ri; Park, Kyung-Ah; Oh, Sei Yeul

    2017-12-01

    To examine the choroidal thickness in patients with indirect traumatic optic neuropathy (TON) Methods: Patients with unilateral traumatic optic neuropathy over a period of 4 years were included in this study. Horizontal and vertical enhanced-depth imaging (EDI) from spectral-domain optical coherence tomography (SD-OCT) scans of the fovea were obtained in patients with unilateral TON within 2 weeks of injury. The main outcome measure was the choroidal thickness at nine locations. The choroidal thickness was compared between affected and unaffected eyes in the TON group, and the mean difference in the choroidal thickness in both eyes was compared between TON and control groups. A total of 16 patients and 20 control subjects were included. The choroidal thickness at horizontal, vertical and average subfoveal, inner temporal, and outer inferior locations was significantly thicker (13-23%) in affected eyes than in unaffected fellow eyes (p = 0.042, 0.046, 0.024, 0.013, 0.018, and 0.027, respectively). The mean difference value between choroidal thickness measurements in both eyes was significantly larger in the TON group than in the control group at the horizontal, vertical and average subfoveal, inner temporal, inner nasal, inner superior, inner inferior, and outer superior locations (p = 0.001, 0.011,  0.05). Eyes affected by TON showed a regionally thicker choroid than unaffected fellow eye. This thick choroid might be due to impaired blood circulation and vascular remodeling of the optic nerve head and choroid. These results help to better understand the pathophysiology of TON.

  12. Effect of thickness on optical properties of thermally evaporated SnS films

    International Nuclear Information System (INIS)

    Selim, M.S.; Gouda, M.E.; El-Shaarawy, M.G.; Salem, A.M.; Abd El-Ghany, W.A.

    2013-01-01

    The effect of film thickness on the structure and optical properties of thermally evaporated SnS film has been studied. SnS films with different thicknesses in the range 152–585 nm were deposited onto clean glass substrates at room temperature. X-ray diffraction study revealed that SnS films of thickness ≥ 283 nm are crystalline, whereas films of lower thickness exhibit poor crystalline with more amorphous background. The crystalline nature of the lower film thickness has been confirmed using transmission electron microscope and the corresponding electron diffraction pattern. The thicker film samples showed nearly stoichiometric chemical composition; however, thinner samples are deficient in S and rich in Sn. The optical property of the deposited films has been investigated in the wavelength range 350–2500 nm. The refractive index increases notably with increasing film thickness. The refractive index for the investigated film thicknesses are adequately described by the effective-single-oscillator model. The static refractive index and the static dielectric constant have been calculated. Analysis of the optical absorption coefficient revealed the presence of direct optical transition and the corresponding band gap values were found to decrease as the film thickness increases. - Highlights: ► X-ray diffraction was used to study the structure of SnS films. ► Transmission electron microscope confirms the crystalline state of SnS films. ► The refractive index increases notably with increasing the film thickness. ► The optical band gap of SnS films decreases with increasing film thickness

  13. Asymmetric transmission of acoustic waves in a layer thickness distribution gradient structure using metamaterials

    Directory of Open Access Journals (Sweden)

    Jung-San Chen

    2016-09-01

    Full Text Available This research presents an innovative asymmetric transmission design using alternate layers of water and metamaterial with complex mass density. The directional transmission behavior of acoustic waves is observed numerically inside the composite structure with gradient layer thickness distribution and the rectifying performance of the present design is evaluated. The layer thickness distributions with arithmetic and geometric gradients are considered and the effect of gradient thickness on asymmetric wave propagation is systematically investigated using finite element simulation. The numerical results indicate that the maximum pressure density and transmission through the proposed structure are significantly influenced by the wave propagation direction over a wide range of audible frequencies. Tailoring the thickness of the layered structure enables the manipulation of asymmetric wave propagation within the desired frequency range. In conclusion, the proposed design offers a new possibility for developing directional-dependent acoustic devices.

  14. Correlation of Gear Surface Fatigue Lives to Lambda Ratio (Specific Film Thickness)

    Science.gov (United States)

    Krantz, Timothy Lewis

    2013-01-01

    The effect of the lubrication regime on gear performance has been recognized, qualitatively, for decades. Often the lubrication regime is characterized by the specific film thickness being the ratio of lubricant film thickness to the composite surface roughness. Three studies done at NASA to investigate gearing pitting life are revisited in this work. All tests were done at a common load. In one study, ground gears were tested using a variety of lubricants that included a range of viscosities, and therefore the gears operated with differing film thicknesses. In a second and third study, the performance of gears with ground teeth and superfinished teeth were assessed. Thicker oil films provided longer lives as did improved surface finish. These datasets were combined into a common dataset using the concept of specific film thickness. This unique dataset of more 258 tests provides gear designers with some qualitative information to make gear design decisions.

  15. Low frequency electrical and magnetic methods for non-destructive analysis of fiber dispersion in fiber reinforced cementitious composites: an overview.

    Science.gov (United States)

    Faifer, Marco; Ferrara, Liberato; Ottoboni, Roberto; Toscani, Sergio

    2013-01-21

    Non-destructive analysis of fiber dispersion in structural elements made of Fiber Reinforced Concrete (FRC) and Fiber Reinforced Cementitious Composites (FRCCs) plays a significant role in the framework of quality control and performance prediction. In this paper, the research activity of the authors in the aforementioned field all over the last lustrum will be reviewed. A method based on the measurement of the inductance of a probe to be placed on the specimen will be presented and its progressive development will be described. Obtained correlation with actual fiber dispersion, as checked by means of destructive methods, as well as with the mechanical performance of the composite will also be presented, in an attempt to address the significance of the method from an engineering application perspective.

  16. A database of worldwide glacier thickness observations

    DEFF Research Database (Denmark)

    Gärtner-Roer, I.; Naegeli, K.; Huss, M.

    2014-01-01

    One of the grand challenges in glacier research is to assess the total ice volume and its global distribution. Over the past few decades the compilation of a world glacier inventory has been well-advanced both in institutional set-up and in spatial coverage. The inventory is restricted to glacier...... the different estimation approaches. This initial database of glacier and ice caps thickness will hopefully be further enlarged and intensively used for a better understanding of the global glacier ice volume and its distribution....... surface observations. However, although thickness has been observed on many glaciers and ice caps around the globe, it has not yet been published in the shape of a readily available database. Here, we present a standardized database of glacier thickness observations compiled by an extensive literature...... review and from airborne data extracted from NASA's Operation IceBridge. This database contains ice thickness observations from roughly 1100 glaciers and ice caps including 550 glacier-wide estimates and 750,000 point observations. A comparison of these observational ice thicknesses with results from...

  17. Uncertainty estimation of ultrasonic thickness measurement

    International Nuclear Information System (INIS)

    Yassir Yassen, Abdul Razak Daud; Mohammad Pauzi Ismail; Abdul Aziz Jemain

    2009-01-01

    The most important factor that should be taken into consideration when selecting ultrasonic thickness measurement technique is its reliability. Only when the uncertainty of a measurement results is known, it may be judged if the result is adequate for intended purpose. The objective of this study is to model the ultrasonic thickness measurement function, to identify the most contributing input uncertainty components, and to estimate the uncertainty of the ultrasonic thickness measurement results. We assumed that there are five error sources significantly contribute to the final error, these sources are calibration velocity, transit time, zero offset, measurement repeatability and resolution, by applying the propagation of uncertainty law to the model function, a combined uncertainty of the ultrasonic thickness measurement was obtained. In this study the modeling function of ultrasonic thickness measurement was derived. By using this model the estimation of the uncertainty of the final output result was found to be reliable. It was also found that the most contributing input uncertainty components are calibration velocity, transit time linearity and zero offset. (author)

  18. Precursor polymer compositions comprising polybenzimidazole

    Science.gov (United States)

    Klaehn, John R.; Peterson, Eric S.; Orme, Christopher J.

    2015-07-14

    Stable, high performance polymer compositions including polybenzimidazole (PBI) and a melamine-formaldehyde polymer, such as methylated, poly(melamine-co-formaldehyde), for forming structures such as films, fibers and bulky structures. The polymer compositions may be formed by combining polybenzimidazole with the melamine-formaldehyde polymer to form a precursor. The polybenzimidazole may be reacted and/or intertwined with the melamine-formaldehyde polymer to form the polymer composition. For example, a stable, free-standing film having a thickness of, for example, between about 5 .mu.m and about 30 .mu.m may be formed from the polymer composition. Such films may be used as gas separation membranes and may be submerged into water for extended periods without crazing and cracking. The polymer composition may also be used as a coating on substrates, such as metal and ceramics, or may be used for spinning fibers. Precursors for forming such polymer compositions are also disclosed.

  19. Normalization of Impact Energy by Laminate Thickness for Compression After Impact Testing

    Science.gov (United States)

    Nettles, A. T.; Hromisin, S. M.

    2013-01-01

    The amount of impact energy used to damage a composite laminate is a critical parameter when assessing residual strength properties. The compression after impact (CAI) strength of impacted laminates is dependent upon how thick the laminate is and this has traditionally been accounted for by normalizing (dividing) the impact energy by the laminate's thickness. However, when comparing CAI strength values for a given lay-up sequence and fiber/resin system, dividing the impact energy by the specimen thickness has been noted by the author to give higher CAI strength values for thicker laminates. A study was thus undertaken to assess the comparability of CAI strength data by normalizing the impact energy by the specimen thickness raised to a power to account for the higher strength of thicker laminates. One set of data from the literature and two generated in this study were analyzed by dividing the impact energy by the specimen thickness to the 1, 1.5, 2, and 2.5 powers. Results show that as laminate thickness and damage severity decreased, the value which the laminate thickness needs to be raised to in order to yield more comparable CAI data increases.

  20. Thick film heater for sensor application

    International Nuclear Information System (INIS)

    Milewski, J; Borecki, M; Kalenik, J; Król, K

    2014-01-01

    A thick film microheater was elaborated. The microheater is intended for fast heating of small volume samples under measurement in optical based system. Thermal analysis of microheater was carried out using finite element method (FEM) for heat transfer calculation as a function of time and space. A nodal heat transfer function was calculated in classical form including all basics mechanisms of heat exchange – heat conduction, convection and radiation were considered. Work focuses on the influence of some construction parameters (ex. length, thermal conductivity of substrate, substrate thickness) on microheater performance. The results show that application of thin substrate of low thermal conductivity and low thickness for miroheater construction and resistor of optimum dimensions leads to significant power consumption decrease and increase of overall optical measurement system performance.

  1. Reliability Criteria for Thick Bonding Wire.

    Science.gov (United States)

    Dagdelen, Turker; Abdel-Rahman, Eihab; Yavuz, Mustafa

    2018-04-17

    Bonding wire is one of the main interconnection techniques. Thick bonding wire is widely used in power modules and other high power applications. This study examined the case for extending the use of traditional thin wire reliability criteria, namely wire flexure and aspect ratio, to thick wires. Eleven aluminum (Al) and aluminum coated copper (CucorAl) wire samples with diameter 300 μm were tested experimentally. The wire response was measured using a novel non-contact method. High fidelity FEM models of the wire were developed and validated. We found that wire flexure is not correlated to its stress state or fatigue life. On the other hand, aspect ratio is a consistent criterion of thick wire fatigue life. Increasing the wire aspect ratio lowers its critical stress and increases its fatigue life. Moreover, we found that CucorAl wire has superior performance and longer fatigue life than Al wire.

  2. Reliability Criteria for Thick Bonding Wire

    Directory of Open Access Journals (Sweden)

    Turker Dagdelen

    2018-04-01

    Full Text Available Bonding wire is one of the main interconnection techniques. Thick bonding wire is widely used in power modules and other high power applications. This study examined the case for extending the use of traditional thin wire reliability criteria, namely wire flexure and aspect ratio, to thick wires. Eleven aluminum (Al and aluminum coated copper (CucorAl wire samples with diameter 300 μm were tested experimentally. The wire response was measured using a novel non-contact method. High fidelity FEM models of the wire were developed and validated. We found that wire flexure is not correlated to its stress state or fatigue life. On the other hand, aspect ratio is a consistent criterion of thick wire fatigue life. Increasing the wire aspect ratio lowers its critical stress and increases its fatigue life. Moreover, we found that CucorAl wire has superior performance and longer fatigue life than Al wire.

  3. Tungsten thick coatings for plasma facing components

    International Nuclear Information System (INIS)

    Riccardi, B.; Pizzuto, A.; Orsini, A.; Libera, S.; Visca, E.; Bertamini, L.; Casadei, F.; Severini, E.; Montanari, R.; Litunovsky, N.

    1998-01-01

    The aim of the R and D activity was to realize thick W coatings on CuCrZr hollow bars and to test the mock ups with respect to thermal fatigue. Eight mock ups provided of 4 mm thick W coating were finally manufactured. The bonding integrity between coating and substrate was checked by means of an Ultrasonic apparatus. Characterisation of coatings was performed in order to assess microstructure, impurity content, density, tensile strength, adhesion strength, thermal conductivity and thermal expansion coefficient. Macroscopic residual strain measurements were performed by means of 'hole drilling' technique. The activities performed demonstrated the feasibility of thick Tungsten coatings on geometries with more complex residual strain distribution. These coatings are reliable armour of medium heat flux plasma facing component. (author)

  4. Partial Thickness Rotator Cuff Tears: Current Concepts

    Science.gov (United States)

    Matthewson, Graeme; Beach, Cara J.; Nelson, Atiba A.; Woodmass, Jarret M.; Ono, Yohei; Boorman, Richard S.; Lo, Ian K. Y.; Thornton, Gail M.

    2015-01-01

    Partial thickness rotator cuff tears are a common cause of pain in the adult shoulder. Despite their high prevalence, the diagnosis and treatment of partial thickness rotator cuff tears remains controversial. While recent studies have helped to elucidate the anatomy and natural history of disease progression, the optimal treatment, both nonoperative and operative, is unclear. Although the advent of arthroscopy has improved the accuracy of the diagnosis of partial thickness rotator cuff tears, the number of surgical techniques used to repair these tears has also increased. While multiple repair techniques have been described, there is currently no significant clinical evidence supporting more complex surgical techniques over standard rotator cuff repair. Further research is required to determine the clinical indications for surgical and nonsurgical management, when formal rotator cuff repair is specifically indicated and when biologic adjunctive therapy may be utilized. PMID:26171251

  5. Partial Thickness Rotator Cuff Tears: Current Concepts

    Directory of Open Access Journals (Sweden)

    Graeme Matthewson

    2015-01-01

    Full Text Available Partial thickness rotator cuff tears are a common cause of pain in the adult shoulder. Despite their high prevalence, the diagnosis and treatment of partial thickness rotator cuff tears remains controversial. While recent studies have helped to elucidate the anatomy and natural history of disease progression, the optimal treatment, both nonoperative and operative, is unclear. Although the advent of arthroscopy has improved the accuracy of the diagnosis of partial thickness rotator cuff tears, the number of surgical techniques used to repair these tears has also increased. While multiple repair techniques have been described, there is currently no significant clinical evidence supporting more complex surgical techniques over standard rotator cuff repair. Further research is required to determine the clinical indications for surgical and nonsurgical management, when formal rotator cuff repair is specifically indicated and when biologic adjunctive therapy may be utilized.

  6. Reliability Criteria for Thick Bonding Wire

    Science.gov (United States)

    Yavuz, Mustafa

    2018-01-01

    Bonding wire is one of the main interconnection techniques. Thick bonding wire is widely used in power modules and other high power applications. This study examined the case for extending the use of traditional thin wire reliability criteria, namely wire flexure and aspect ratio, to thick wires. Eleven aluminum (Al) and aluminum coated copper (CucorAl) wire samples with diameter 300 μm were tested experimentally. The wire response was measured using a novel non-contact method. High fidelity FEM models of the wire were developed and validated. We found that wire flexure is not correlated to its stress state or fatigue life. On the other hand, aspect ratio is a consistent criterion of thick wire fatigue life. Increasing the wire aspect ratio lowers its critical stress and increases its fatigue life. Moreover, we found that CucorAl wire has superior performance and longer fatigue life than Al wire. PMID:29673194

  7. Increased endometrial thickness in women with hypertension.

    Science.gov (United States)

    Bornstein, J; Auslender, R; Goldstein, S; Kohan, R; Stolar, Z; Abramovici, H

    2000-09-01

    We noticed an increase in endometrial thickness in women with hypertension who were treated with a combination of medications, including beta-blockers. The purpose of this study was to examine whether the endometrium of hypertensive women is thicker than that of healthy women and to determine whether endometrial thickening in hypertensive women is directly related to the antihypertensive beta-blocker treatment. We compared 3 groups of postmenopausal patients as follows: (1) women with a history of essential hypertension treated with a combination of medications, including beta-blockers; (2) women with a history of hypertension treated with a combination of medications that did not include beta-blockers; and (3) healthy women without hypertension. All patients were interviewed and examined, blood tests were performed, and endometrial thickness in the anterior-posterior diameter was measured by vaginal ultrasonography. Among the exclusion criteria were diabetes or an abnormal fasting blood glucose level, obesity, hormonal medication or replacement hormonal therapy during the previous 6 months, and a history of hormonal disturbances, infertility, or polycystic ovary syndrome. Of 45 hypertensive women enrolled in the study, 22 were treated with a beta-blocker combination medication and 23 were treated with other antihypertensive medications. They were compared with 25 healthy women. There was no statistically significant difference in endometrial thickness between women treated with medications, including beta-blockers, and those who were treated with other hypotensive agents. Twenty percent of women with hypertension and none of the healthy women had endometrium >5 mm thick (P infinity). Twenty percent of hypertensive postmenopausal women were found to have increased endometrial thickness. However, we were unable to substantiate an association between the type of treatment administered, whether beta-blockers were included, and the increase in endometrial thickness.

  8. Durability of Capped Wood Plastic Composites

    Science.gov (United States)

    Mark Mankowski; Mark J. Manning; Damien P. Slowik

    2015-01-01

    Manufacturers of wood plastic composites (WPCs) have recently introduced capped decking to their product lines. These new materials have begun to take market share from the previous generation of uncapped products that possessed a homogenous composition throughout the thickness of their cross-section. These capped offerings have been introduced with claims that the...

  9. Glue Film Thickness Measurements by Spectral Reflectance

    International Nuclear Information System (INIS)

    Marshall, B.R.

    2010-01-01

    Spectral reflectance was used to determine the thickness of thin glue layers in a study of the effect of the glue on radiance and reflectance measurements of shocked-tin substrates attached to lithium fluoride windows. Measurements based on profilometry of the components were found to be inaccurate due to flatness variations and deformation of the tin substrate under pressure during the gluing process. The accuracy of the spectral reflectance measurements were estimated to be ±0.5 (micro)m, which was sufficient to demonstrate a convincing correlation between glue thickness and shock-generated light.

  10. Terahertz Mapping of Microstructure and Thickness Variations

    Science.gov (United States)

    Roth, Donald J.; Seebo, Jeffrey P.; Winfree, William P.

    2010-01-01

    A noncontact method has been devised for mapping or imaging spatial variations in the thickness and microstructure of a layer of a dielectric material. The method involves (1) placement of the dielectric material on a metal substrate, (2) through-the-thickness pulse-echo measurements by use of electromagnetic waves in the terahertz frequency range with a raster scan in a plane parallel to the substrate surface that do not require coupling of any kind, and (3) appropriate processing of the digitized measurement data.

  11. Glue Film Thickness Measurements by Spectral Reflectance

    Energy Technology Data Exchange (ETDEWEB)

    B. R. Marshall

    2010-09-20

    Spectral reflectance was used to determine the thickness of thin glue layers in a study of the effect of the glue on radiance and reflectance measurements of shocked-tin substrates attached to lithium fluoride windows. Measurements based on profilometry of the components were found to be inaccurate due to flatness variations and deformation of the tin substrate under pressure during the gluing process. The accuracy of the spectral reflectance measurements were estimated to be ±0.5 μm, which was sufficient to demonstrate a convincing correlation between glue thickness and shock-generated light.

  12. Geologic thickness data: Candidate repository horizons

    International Nuclear Information System (INIS)

    Cross, R.W.; Fairchild, K.R.

    1985-01-01

    This data package contains information on the thickness of the Umtanum, McCoy Canyon, Cohassett, and Rocky Coulee flows and their intraflow structures in 20 boreholes and 2 surface sections in the Pasco Basin. Thickness data are for total flow, flow top, entablature, and colonnade (or just flow top and dense interior in some cases). Summary figures which contain descriptions and footages are included. SD-BWI-DP-011, Rev. 2 replaces SD-BWI-DP-011, Rev. A-0 in its entirety. (Rev. A-0 replaced Rev. 0-0.) 5 refs

  13. Hot rolling of thick uranium molybdenum alloys

    Science.gov (United States)

    DeMint, Amy L.; Gooch, Jack G.

    2015-11-17

    Disclosed herein are processes for hot rolling billets of uranium that have been alloyed with about ten weight percent molybdenum to produce cold-rollable sheets that are about one hundred mils thick. In certain embodiments, the billets have a thickness of about 7/8 inch or greater. Disclosed processes typically involve a rolling schedule that includes a light rolling pass and at least one medium rolling pass. Processes may also include reheating the rolling stock and using one or more heavy rolling passes, and may include an annealing step.

  14. Preparation and characterization of thick BSCCO 2223 films

    International Nuclear Information System (INIS)

    Ciancio, G; Avila, A; Malachevsky, M.T; Ovidio, C.A

    2002-01-01

    Among the most widespread applications for critical high-temperature ceramic superconductors are for silver veined tapes, with the superconductor in the middle. These tapes are prepared by the powder- in - tube method. To attain high densities of critical current, the ceramic material must have a certain texture, with the grains oriented with the c axis perpendicular to the direction in which the current circulates. In the system that was studied, the degree of orientation increases as the distance to the vein decreases, with the maximum being in the silver-ceramic inter-phase. Superconductor tapes become inconvenient when defining the ceramic, especially because of the orientation of their plates as a function of the distance to the silver. Although the silver can be dissolved by a chemical attack in order to uncover the ceramic, greater precaution is needed while manipulating the superconductor and obtaining representative data. The behavior of thick films of the compound BSCCO 2223, deposited on silver sheets, forming silver-ceramic composites, was studied. These sheets simulate the silver-ceramic inter-phase and the distribution of the grains towards the center in a thick tape. After the samples were prepared, the phases that were present were characterized by x-ray diffraction and the resulting microstructure was analyzed with a SEM (Scanning Electron Microscope). Its mechanical properties were evaluated, following the formation and propagation of cracks in real time using four point flexion microassays inside the SEM chamber, as well as generating tension-deformation curves. The method of preparation of the thick films is discussed and its influence on the results obtained with the different characterizations (cw)

  15. Weld repair issues in thick section austenitic pipework

    International Nuclear Information System (INIS)

    Goodwin, S.J.; Price, A.T.

    1989-03-01

    Thick section austenitic Type 316 Stainless steel, in the solution treated condition, has been used in Central Electricity Generating Board plant in the United Kingdom for some three decades and has given good service. Repair and replacement of this material after long term service is becoming a requirement and is complicated by the precipitation hardening and sensitisation of the materials. This paper summarises the compositional, microstructural and ageing characteristics of the wrought material and weld metals and the consequences for materials properties. Post weld heat treatment options are outlined and sensitisation to stress corrosion cracking is discussed. Finally, some examples of cracking that has occurred in plant after long term operation are given and weld repair research requirements are noted. (author)

  16. Vibration of Elastic Functionally Graded Thick Rings

    Directory of Open Access Journals (Sweden)

    Guang-Hui Xu

    2017-01-01

    Full Text Available The free vibration behaviors of functionally graded rings were investigated theoretically. The material graded in the thickness direction according to the power law rule and the rings were assumed to be in plane stress and plane strain states. Based on the first-order shear deformation theory and the kinetic relation of von Kárman type, the frequency equation for free vibration of functionally graded ring was derived. The derived results were verified by those in literatures which reveals that the present theory can be appropriate to predict the free vibration characteristics for quite thick rings with the radius-to-thickness ratio from 60 down to 2.09. Comparison between the plane stress case and the plane strain case indicates a slight difference. Meanwhile, the effects of the structural dimensional parameters and the material inhomogeneous parameter are examined. It is interesting that the value of the logarithmic form of vibration frequency is inversely proportional to the logarithmic form of the radius-to-thickness ratio or the mean radius.

  17. Percolation effect in thick film superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Sali, R.; Harsanyi, G. [Technical Univ. of Budapest (Hungary)

    1994-12-31

    A thick film superconductor paste has been developed to study the properties of granulated superconductor materials, to observe the percolation effect and to confirm the theory of the conducting mechanism in the superconducting thick films. This paste was also applied to make a superconducting planar transformer. Due to high T{sub c} and advantageous current density properties the base of the paste was chosen to be of Bi(Pb)SrCaCuO system. For contacts a conventional Ag/Pt paste was used. The critical temperature of the samples were between 110 K and 115 K depending on the printed layer thickness. The critical current density at the boiling temperature of the liquid He- was between 200-300 A/cm{sup 2}. The R(T) and V(I) functions were measured with different parameters. The results of the measurements have confirmed the theory of conducting mechanism in the material. The percolation structure model has been built and described. As an application, a superconducting planar thick film transformer was planned and produced. Ten windings of the transformer were printed on one side of the alumina substrate and one winding was printed on the other side. The coupling between the two sides was possible through the substrate. The samples did not need special drying and firing parameters. After the preparation, the properties of the transformer were measured. The efficiency and the losses were determined. Finally, some fundamental advantages and problems of the process were discussed.

  18. Aluminum oxide film thickness and emittance

    International Nuclear Information System (INIS)

    Thomas, J.K.; Ondrejcin, R.S.

    1991-11-01

    Aluminum reactor components which are not actively cooled could be subjected to high temperatures due to gamma heating after the core coolant level dropped during the ECS phase of a hypothetical LOCA event. Radiative heat transfer is the dominant heat transfer process in this scenario and therefore the emittance of these components is of interest. Of particular interest are the safety rod thimbles and Mark 60B blanket assemblies; for the K Reactor, these components have been exposed to low temperature (< 55 degrees C) moderator for about a year. The average moderator temperature was assumed to be 30 degrees C. The Al oxide film thickness at this temperature, after one year of exposure, is predicted to be 6.4 μm ± 10%; insensitive to exposure time. Dehydration of the film during the gamma heating accident would result in a film thickness of 6.0 μm ± 11%. Total hemispherical emittance is predicted to be 0.69 at 96 degrees C, decreasing to 0.45 at 600 degrees C. Some phenomena which would tend to yield thicker oxide films in the reactor environment relative to those obtained under experimental conditions were neglected and the predicted film thickness values are therefore conservative. The emittance values predicted for a given film thickness are also conservative. The conservativisms inherent in the predicted emittance are particularly relevant for uncertainty analysis of temperatures generated using these values

  19. Thick Slice and Thin Slice Teaching Evaluations

    Science.gov (United States)

    Tom, Gail; Tong, Stephanie Tom; Hesse, Charles

    2010-01-01

    Student-based teaching evaluations are an integral component to institutions of higher education. Previous work on student-based teaching evaluations suggest that evaluations of instructors based upon "thin slice" 30-s video clips of them in the classroom correlate strongly with their end of the term "thick slice" student evaluations. This study's…

  20. Determination of the Optimum Thickness of Approximately ...

    African Journals Online (AJOL)

    In an attempt to conserve the world's scarce energy and material resources, a balance between the cost of heating a material and the optimum thickness of the material becomes vey essential. One of such materials is the local cast aluminium pot commonly used as cooking ware in Nigeria. This paper therefore sets up a ...

  1. Percolation effect in thick film superconductors

    International Nuclear Information System (INIS)

    Sali, R.; Harsanyi, G.

    1994-01-01

    A thick film superconductor paste has been developed to study the properties of granulated superconductor materials, to observe the percolation effect and to confirm the theory of the conducting mechanism in the superconducting thick films. This paste was also applied to make a superconducting planar transformer. Due to high T c and advantageous current density properties the base of the paste was chosen to be of Bi(Pb)SrCaCuO system. For contacts a conventional Ag/Pt paste was used. The critical temperature of the samples were between 110 K and 115 K depending on the printed layer thickness. The critical current density at the boiling temperature of the liquid He- was between 200-300 A/cm 2 . The R(T) and V(I) functions were measured with different parameters. The results of the measurements have confirmed the theory of conducting mechanism in the material. The percolation structure model has been built and described. As an application, a superconducting planar thick film transformer was planned and produced. Ten windings of the transformer were printed on one side of the alumina substrate and one winding was printed on the other side. The coupling between the two sides was possible through the substrate. The samples did not need special drying and firing parameters. After the preparation, the properties of the transformer were measured. The efficiency and the losses were determined. Finally, some fundamental advantages and problems of the process were discussed

  2. Crustal thickness controlled by plate tectonics

    DEFF Research Database (Denmark)

    Artemieva, Irina M.; Meissner, Rolf

    2012-01-01

    /gabbro–eclogite phase transition in crustal evolution and the links between lithosphere recycling, mafic magmatism, and crustal underplating. We advocate that plate tectonics processes, togetherwith basalt/gabbro–eclogite transition, limit crustal thickness worldwide by providing effective mechanisms of crustal...

  3. Factors Influencing Endometrial Thickness in Postmenopausal Women

    African Journals Online (AJOL)

    Background: Cut‑off values for endometrial thickness (ET) in asymptomatic postmenopausal woman have been standardized. However, there are no comprehensive studies to document how various factors can influence the ET after the age of menopause. Aim: To study the various factors influencing the ET in ...

  4. Quality assurance in thick-walled weldments

    International Nuclear Information System (INIS)

    Straub, H.

    1978-01-01

    Some guidelines are given here for judging the magnitude of flaws in welded thick-walled components (such as nuclear reactor vessels). The actually critical defect sizes are analysed, taking into account the residual stresses after welding and after annealing also. Various procedures for repairing such work are then indicated. (Auth.)

  5. Mechanical properties of additively manufactured thick honeycombs

    NARCIS (Netherlands)

    Hedayati, R.; Sadighi, M.; Mohammadi-Aghdam, M; Zadpoor, A.A.

    2016-01-01

    Honeycombs resemble the structure of a number of natural and biological materials such as cancellous bone, wood, and cork. Thick honeycomb could be also used for energy absorption applications. Moreover, studying the mechanical behavior of honeycombs under in-plane loading could help understanding

  6. Thickness dependence of nanofilm elastic modulus

    Czech Academy of Sciences Publication Activity Database

    Fedorchenko, Alexander I.; Wang, A. B.; Cheng, H.H.

    2009-01-01

    Roč. 94, č. 15 (2009), s. 152111-152113 ISSN 0003-6951 Institutional research plan: CEZ:AV0Z20760514 Keywords : nanofilm * elastic modulus * thickness dependence Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.554, year: 2009 http://link.aip.org/link/?APPLAB/94/152111/1

  7. Impact of spacer thickness on biofouling in forward osmosis

    KAUST Repository

    Valladares Linares, Rodrigo

    2014-06-01

    Forward osmosis (FO) indirect desalination systems integrate wastewater recovery with seawater desalination. Niche applications for FO systems have been reported recently, due to the demonstrated advantages compared to conventional high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO). Among them, wastewater recovery has been identified to be particularly suitable for practical applications. However, biofouling in FO membranes has rarely been studied in applications involving wastewater effluents. Feed spacers separating the membrane sheets in cross-flow systems play an important role in biofilm formation. The objective of this study was to determine the influence of feed spacer thickness (28, 31 and 46mil) on biofouling development and membrane performance in a FO system, using identical cross-flow cells in parallel studies. Flux development, biomass accumulation, fouling localization and composition were determined and analyzed. For all spacer thicknesses, operated at the same feed flow and the same run time, the same amount of biomass was found, while the flux reduction decreased with thicker spacers. These observations are in good agreement with biofouling studies for RO systems, considering the key differences between FO and RO. Our findings contradict previous cross-flow studies on particulate/colloidal fouling, where higher cross-flow velocities improved system performance. Thicker spacers reduced the impact of biofouling on FO membrane flux. © 2014 Elsevier Ltd.

  8. Impact of spacer thickness on biofouling in forward osmosis.

    Science.gov (United States)

    Valladares Linares, R; Bucs, Sz S; Li, Z; AbuGhdeeb, M; Amy, G; Vrouwenvelder, J S

    2014-06-15

    Forward osmosis (FO) indirect desalination systems integrate wastewater recovery with seawater desalination. Niche applications for FO systems have been reported recently, due to the demonstrated advantages compared to conventional high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO). Among them, wastewater recovery has been identified to be particularly suitable for practical applications. However, biofouling in FO membranes has rarely been studied in applications involving wastewater effluents. Feed spacers separating the membrane sheets in cross-flow systems play an important role in biofilm formation. The objective of this study was to determine the influence of feed spacer thickness (28, 31 and 46 mil) on biofouling development and membrane performance in a FO system, using identical cross-flow cells in parallel studies. Flux development, biomass accumulation, fouling localization and composition were determined and analyzed. For all spacer thicknesses, operated at the same feed flow and the same run time, the same amount of biomass was found, while the flux reduction decreased with thicker spacers. These observations are in good agreement with biofouling studies for RO systems, considering the key differences between FO and RO. Our findings contradict previous cross-flow studies on particulate/colloidal fouling, where higher cross-flow velocities improved system performance. Thicker spacers reduced the impact of biofouling on FO membrane flux. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Impact of spacer thickness on biofouling in forward osmosis

    KAUST Repository

    Valladares Linares, Rodrigo; Bucs, Szilard; Li, Z.; AbuGhdeeb, M.; Amy, Gary L.; Vrouwenvelder, Johannes S.

    2014-01-01

    Forward osmosis (FO) indirect desalination systems integrate wastewater recovery with seawater desalination. Niche applications for FO systems have been reported recently, due to the demonstrated advantages compared to conventional high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO). Among them, wastewater recovery has been identified to be particularly suitable for practical applications. However, biofouling in FO membranes has rarely been studied in applications involving wastewater effluents. Feed spacers separating the membrane sheets in cross-flow systems play an important role in biofilm formation. The objective of this study was to determine the influence of feed spacer thickness (28, 31 and 46mil) on biofouling development and membrane performance in a FO system, using identical cross-flow cells in parallel studies. Flux development, biomass accumulation, fouling localization and composition were determined and analyzed. For all spacer thicknesses, operated at the same feed flow and the same run time, the same amount of biomass was found, while the flux reduction decreased with thicker spacers. These observations are in good agreement with biofouling studies for RO systems, considering the key differences between FO and RO. Our findings contradict previous cross-flow studies on particulate/colloidal fouling, where higher cross-flow velocities improved system performance. Thicker spacers reduced the impact of biofouling on FO membrane flux. © 2014 Elsevier Ltd.

  10. Healable Composites

    Science.gov (United States)

    2012-03-28

    oriented fibers and healable polymer matrix 4. Laminate pre-preg layers to form composite panels with minimal voids & defects 5. Characterize the...composites: determine mechanical and crack healing properties (4, 5) Composite (3) Prepreg (2) Polymer (1) Furan (1) Maleimide Healable Composites...Develop pre-preg system of oriented fibers and healable polymer matrix 4. Laminate pre-preg layers to form composite panels with minimal voids & defects

  11. METALLICITY GRADIENTS OF THICK DISK DWARF STARS

    Energy Technology Data Exchange (ETDEWEB)

    Carrell, Kenneth; Chen Yuqin; Zhao Gang, E-mail: carrell@nao.cas.cn [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2012-12-01

    We examine the metallicity distribution of the Galactic thick disk using F, G, and K dwarf stars selected from the Sloan Digital Sky Survey, Data Release 8. Using the large sample of dwarf stars with proper motions and spectroscopically determined stellar parameters, metallicity gradients in the radial direction for various heights above the Galactic plane and in the vertical direction for various radial distances from the Galaxy center have been found. In particular, we find a vertical metallicity gradient of -0.113 {+-} 0.010 (-0.125 {+-} 0.008) dex kpc{sup -1} using an isochrone (photometric) distance determination in the range 1 kpc <|Z| < 3 kpc, which is the vertical height range most consistent with the thick disk of our Galaxy. In the radial direction, we find metallicity gradients between +0.02 and +0.03 dex kpc{sup -1} for bins in the vertical direction between 1 kpc <|Z| < 3 kpc. Both of these results agree with similar values determined from other populations of stars, but this is the first time a radial metallicity gradient for the thick disk has been found at these vertical heights. We are also able to separate thin and thick disk stars based on kinematic and spatial probabilities in the vertical height range where there is significant overlap of these two populations. This should aid further studies of the metallicity gradients of the disk for vertical heights lower than those studied here but above the solar neighborhood. Metallicity gradients in the thin and thick disks are important probes into possible formation scenarios for our Galaxy and a consistent picture is beginning to emerge from results using large spectroscopic surveys, such as the ones presented here.

  12. Nearshore sediment thickness, Fire Island, New York

    Science.gov (United States)

    Locker, Stanley D.; Miselis, Jennifer L.; Buster, Noreen A.; Hapke, Cheryl J.; Wadman, Heidi M.; McNinch, Jesse E.; Forde, Arnell S.; Stalk, Chelsea A.

    2017-04-03

    Investigations of coastal change at Fire Island, New York (N.Y.), sought to characterize sediment budgets and determine geologic framework controls on coastal processes. Nearshore sediment thickness is critical for assessing coastal system sediment availability, but it is largely unquantified due to the difficulty of conducting geological or geophysical surveys across the nearshore. This study used an amphibious vessel to acquire chirp subbottom profiles. These profiles were used to characterize nearshore geology and provide an assessment of nearshore sediment volume. Two resulting sediment-thickness maps are provided: total Holocene sediment thickness and the thickness of the active shoreface. The Holocene sediment section represents deposition above the maximum flooding surface that is related to the most recent marine transgression. The active shoreface section is the uppermost Holocene sediment, which is interpreted to represent the portion of the shoreface thought to contribute to present and future coastal behavior. The sediment distribution patterns correspond to previously defined zones of erosion, accretion, and stability along the island, demonstrating the importance of sediment availability in the coastal response to storms and seasonal variability. The eastern zone has a thin nearshore sediment thickness, except for an ebb-tidal deposit at the wilderness breach caused by Hurricane Sandy. Thicker sediment is found along a central zone that includes shoreface-attached sand ridges, which is consistent with a stable or accretional coastline in this area. The thickest overall Holocene section is found in the western zone of the study, where a thicker lower section of Holocene sediment appears related to the westward migration of Fire Island Inlet over several hundred years.

  13. Biosensors Based on Ultrathin Film Composite Membranes

    Science.gov (United States)

    1994-01-25

    composite membranes should have a number C •’ of potential advantages including fast response time, simplicity of construction, and applicability to a number...The support membrane for the ultrathin film composite was an Anopore ( Alltech Associates) microporous alumina filter, these membranes are 55 Pm thick...constant 02 concentration in this solution. Finally, one of the most important potential advantage of a sensor based on an ultrathin film composite

  14. Development of Polymethylmethacrylate Based Composite for Gas Sensing Application

    Directory of Open Access Journals (Sweden)

    S. Devikala

    2011-01-01

    Full Text Available Gas detection instruments are increasingly needed for industrial health and safety, environmental monitoring and process control. Conductive polymer composites have various industrial applications. The composite prepared by mixing carbon black with polymethylmethacrylate (PMMA has very good gas sensing applications. The gas sensors based on carbon nanotube/polymer, ceramic and metal oxide composites such as epoxy, polyimide, PMMA / Barium titanate and tin oxide have also been developed. In the present work, a new composite has been prepared by using PMMA and ammonium dihydrogen phosphate (ADP. The PMMA/Ammonium dihydrogen phosphate (PMADP composites PMADP 1 and PMADP 2 were characterized by using Powder XRD. The thick films of the composite on glass plates were prepared by using a spin coating unit at 9000 rpm. The application of the thick film as gas sensor has been studied between 0 and 2000 seconds. The results reveal that the thick film of PMADP composite can function as a very good gas sensor.

  15. Thickness evaluation using a new relationship between film density and penetrated thickness in radiography

    International Nuclear Information System (INIS)

    Lee, Sung Sik; Kim, Young H.

    2005-01-01

    In order to improve the accuracies in the thickness evaluation using radiography, a new relationship between film density and penetrated thickness has been proposed, and experimental verification of the proposed relationship was carried out by using the X- and γ-ray radiographs of two carbon steel step wedges. A new parameter, the logarithmic gradient of film density, was defined in order to express the characteristics of the radiographic film for wider range of film density. A new relationship between the film density and the penetrated thickness were formulated using the logarithmic gradient of the film density. In experiment, the logarithmic gradient of the film density was independent on both the exposure and the film density and measured for the radiographic film used in the present work from the slope of the fitting lines for the same penetrated thickness. Experimental results verifies the accuracy of the proposed relationship between film density and the penetrated thickness for the range of film density from 1.0 to 3.5. The thickness can be more accurately determined by using the proposed relationship and the parameters determined by experiment. It is also found that the γ-ray having simple energy spectrum is more appropriate radiation source for the evaluation of the thickness from the film density of the radiograph

  16. Choroidal thickness in Malaysian eyes with full-thickness macular holes

    Directory of Open Access Journals (Sweden)

    Chew Y Tan

    2018-02-01

    Full Text Available AIM: To compare choroidal thickness at the macula in eyes with unilateral idiopathic full-thickness macular holes(FTMHwith that of unaffected fellow eyes, and eyes of normal control patients.METHODS: Cross-sectional study. Thirty patients with unilateral idiopathic FTMH and thirty age, sex, and race-matched controls were recruited. Axial lengths were measured using laser interferometry. Enhanced depth imaging optical coherence tomography images were obtained using Heidelberg spectral-domain optical coherence tomography. Choroidal thickness was measured at the fovea, and at 1 mm and 2 mm nasally, temporally, superiorly and inferiorly from the center of the fovea. Statistical analysis was performed using independent and paired t-tests, chi-square tests, and Pearson correlation tests(PRESULTS: The mean subfoveal choroidal thickness was 201.0±44.0 μm in the FTMH group, 225.3±51.4 μm in the fellow eye group and 262.3±70.3 μm in the control group. The choroid was thinner in FTMH eyes at all locations when compared to control eyes(PPP>0.05. Choroidal thickness was generally highest subfoveally and lowest nasally. Subfoveal choroidal thickness was negatively correlated with age(r=-0.278, P=0.032, and axial length(r=-0.328, P=0.011.CONCLUSION: Choroidal thickness is lower in both eyes of patients with unilateral FTMH compared to healthy control eyes.

  17. Study on Gas Sensing Performance of TiO2 Screen Printed Thick Films

    Directory of Open Access Journals (Sweden)

    C. G. DIGHAVKAR

    2009-02-01

    Full Text Available Titanium dioxide (TiO2 thick films were prepared on alumina substrate by using screen printing technique. After preparation, the films were fired at temperature range 600 -1000 ºC for two hour. Morphological, compositional and structural properties of the film samples were performed by means of several techniques, including scanning electron microscopy (SEM, Energy dispersive spectroscopy (EDS, X-ray diffraction techniques. We explore the various gases to study the sensing performance of the TiO2 thick films. The maximum response was reported to film fired at 800 0C for LPG gas at 350 0C operating temperature.

  18. Effect of Firing Temperature on Humidity Sensing Properties of SnO2 Thick Film Resistor

    Directory of Open Access Journals (Sweden)

    R. Y. Borse

    2009-12-01

    Full Text Available Thick films of SnO2 were prepared using standard screen printing technique. The films were dried and fired at different temperatures. Tin-oxide is an n-type wide band gap semiconductor, whose resistance is described as a function of relative humidity. An increasing firing temperature on SnO2 film increases the sensitivity to humidity. The parameters such as sensitivity, response times and hysteresis of the SnO2 film sensors have been evaluated. The thick films were characterized by XRD, SEM and EDAX and grain size, composition of elements, relative phases are obtained.

  19. Mandibular thickness measurements in young dentate adults.

    Science.gov (United States)

    Beaty, Narlin B; Le, Thomas T

    2009-09-01

    To measure thicknesses in clinical landmark areas of the dentate mandibles of young men and women. Using standard radiologic software, we obtained mean (SD) thickness measurements at the inferior or posterior borders of the mandible at the following 7 surgically useful sites: (1) the symphysis, (2) a point halfway between the symphysis and the mental nerve, (3) the mental nerve, (4) a point halfway between the mental nerve and the facial artery notch, (5) the facial artery notch, (6) the angle vertex, and (7) the ramus-condylar neck border. University hospital. A total of 150 dentate men and 75 dentate women aged 18 to 30 years who had undergone computed tomography of the head and neck region during the period of December 20, 2006 to February 20, 2007. Thicknesses of 7 mandibular sites. Mean (SD) thicknesses at the 7 mandibular sites were as follows: symphysis, 14.03 (1.53) mm for men and 13.21 (1.46) mm for women; halfway between the symphysis and the mental nerve, 11.17 (1.37) mm for men and 10.00 (1.08) mm for women; mental nerve, 9.48 (1.28) mm for men and 8.72 (1.00) mm for women; halfway between the mental nerve and the facial artery notch, 10.33 (1.24) mm for men and 9.45 (0.92) mm for women; facial artery notch, 7.27 (0.82) mm for men and 7.10 (0.88) mm for women; angle vertex, 5.42 (0.90) mm for men and 5.39 (0.66) mm for women; and ramus-condylar neck border, 5.90 (0.86) mm for men and 5.85 (0.71) mm for women. Clinical landmark areas in young dentate mandibles have mean thicknesses with limited SDs. The thickness measurements obtained at the sites in this study provide practical reference information for mandibular reconstruction and bicortical screw length estimation.

  20. The mobility of growth twins synthesized by sputtering: Tailoring the twin thickness

    International Nuclear Information System (INIS)

    Velasco, Leonardo; Hodge, Andrea M.

    2016-01-01

    The current work presents a protean twin thickness contour zone map that illustrates how the nucleation and the mobility of twin boundaries affects the twin thickness of sputtered films. The twin thickness contour zone map can be used as a versatile guide to synthesize fully nanotwinned films with tailored twin thicknesses in materials with a wide range of stacking fault energies. The nucleation and mobility of twin boundaries was studied in four Cu alloys of different compositions (Cu-6wt.%Al, Cu-4wt.%Al, Cu-2wt.%Al, and Cu-10wt.%Ni), having stacking fault energies ranging from 6 mJ/m 2 to 60 mJ/m 2 . The films were synthesized by magnetron sputtering and characterized by transmission electron microscopy, where the twin thickness varied from 2 nm to 35 nm. Our experimental results show that it is possible to control the twin thickness. Three main mechanisms are explained to describe twin nucleation and twin boundary mobility, which are correlated to the interplay of specific sputtering conditions and the deposition temperature.

  1. Effect of Ni Doping on Gas Sensing Performance of ZnO Thick Film Resistor

    Directory of Open Access Journals (Sweden)

    M. K. DEORE

    2010-11-01

    Full Text Available This work investigates the use of ZnO-NiO as a H2S metal oxide thick film gas sensor. To find the optimum ratio of NiO to ZnO, two compositions were prepared using different molecular percentages and prepared as a thick film paste. These pastes were then screen-printed onto glass substrates with suitable binder. The final composition of each film was determined using SEM analysis. The films were used to detect CO, CL2, ethanol, Amonia and H2S. For each composition tested, the highest responses where displayed for H2S gas. The Thick film having composition of equal molar ZnO and NiO shows the highest response at operating temp. 350 0C for 100 ppm level. The gas response, selectivity, response and recovery time of the sensor were measured and presented. The role played by NiO species is to improve the gas sensing performance is discussed.

  2. Post-curing conversion kinetics as functions of the irradiation time and increment thickness

    Directory of Open Access Journals (Sweden)

    Nicola Scotti

    2013-04-01

    Full Text Available Objective: This study evaluated the variation of conversion degree (DC in the 12 hours following initial photoactivation of a low-shrinkage composite resin (Venus Diamond. Material and Methods: The conversion degree was monitored for 12 hours using Attenuated Total Reflection (ATR F-TIR Spectroscopy. The composite was placed in 1 or 2 mm rings and cured for 10 or 20 seconds with a LED lamp. ATR spectra were acquired from the bottom surface of each sample immediately after the initial photoactivation (P=0, 30 minutes (P=0.5 and 12 hours after photoactivation (P=12 in order to obtain the DC progression during the post-curing period. Interactions between thickness (T, irradiation time (I and post-curing (P on the DC were calculated through ANOVA testing. Results: All the first order interactions were statistically significant, with the exception of the T-P interaction. Furthermore, the shift from P=0 to P=0.5 had a statistically higher influence than the shift from P=0.5 to P=12. The post-curing period played a fundamental role in reaching higher DC values with the low-shrinkage composite resin tested in this study. Moreover, both the irradiation time and the composite thickness strongly influenced the DC. Conclusions: Increased irradiation time may be useful in obtaining a high conversion degree (DC with a low-shrinkage nano-hybrid composite resin, particularly with 2 mm composite layers.

  3. Properties of conductive thick-film inks

    Science.gov (United States)

    Holtze, R. F.

    1972-01-01

    Ten different conductive inks used in the fabrication of thick-film circuits were evaluated for their physical and handling properties. Viscosity, solid contents, and spectrographic analysis of the unfired inks were determined. Inks were screened on ceramic substrates and fired for varying times at specified temperatures. Selected substrates were given additional firings to simulate the heat exposure received if thick-film resistors were to be added to the same substrate. Data are presented covering the (1) printing characteristics, (2) solderability using Sn-63 and also a 4 percent silver solder, (3) leach resistance, (4) solder adhesion, and (5) wire bonding properties. Results obtained using different firing schedules were compared. A comparison was made between the various inks showing general results obtained for each ink. The changes in firing time or the application of a simulated resistor firing had little effect on the properties of most inks.

  4. Metallic oxide switches using thick film technology

    Science.gov (United States)

    Patel, D. N.; Williams, L., Jr.

    1974-01-01

    Metallic oxide thick film switches were processed on alumina substrates using thick film technology. Vanadium pentoxide in powder form was mixed with other oxides e.g., barium, strontium copper and glass frit, ground to a fine powder. Pastes and screen printable inks were made using commercial conductive vehicles and appropriate thinners. Some switching devices were processed by conventional screen printing and firing of the inks and commercial cermet conductor terminals on 96% alumina substrates while others were made by applying small beads or dots of the pastes between platinum wires. Static, and dynamic volt-ampere, and pulse tests indicate that the switching and self-oscillatory characteristics of these devices could make them useful in memory element, oscillator, and automatic control applications.

  5. Gluteal fat thickness in pelvic CT

    International Nuclear Information System (INIS)

    Park, Jeong Mi; Jung, Se Young; Lee, Jae Mun; Park, Seog Hee; Kim, Choon Yul; Bahk, Yong Whee

    1986-01-01

    Many calcifications due to fat necrosis in the buttocks detected on the pelvis roentgenograms suggest that the majority of injections intended to be intramuscular actually are delivered into fat. We measured thickness of adult gluteal fat to decide whether the injection using needle of usual length is done into fat or muscle. We measured the vertical thickness of the subcutaneous fat at a point of 2-3cm above the femoral head cut slice with randomly collected 116 cases of adults in the department of Radiology, St. Mary's Hospital, Catholic Medical College. We found that 32% female cases might actually receive on intra adipose injection when a needle of maximum 3.8cm length is inserted into the buttock. If deposition into muscle is desirable, we need to choose needle whose length is appropriate for the site of injection and the patient's deposits of fat.

  6. Hybrid Optimization for Wind Turbine Thick Airfoils

    Energy Technology Data Exchange (ETDEWEB)

    Grasso, F. [ECN Wind Energy, Petten (Netherlands)

    2012-06-15

    One important element in aerodynamic design of wind turbines is the use of specially tailored airfoils to increase the ratio of energy capture and reduce cost of energy. This work is focused on the design of thick airfoils for wind turbines by using numerical optimization. A hybrid scheme is proposed in which genetic and gradient based algorithms are combined together to improve the accuracy and the reliability of the design. Firstly, the requirements and the constraints for this class of airfoils are described; then, the hybrid approach is presented. The final part of this work is dedicated to illustrate a numerical example regarding the design of a new thick airfoil. The results are discussed and compared to existing airfoils.

  7. Beta ray backscattering studies for thickness measurements

    Energy Technology Data Exchange (ETDEWEB)

    Singh, M; Sharma, K K [Punjabi Univ., Patiala (India). Nuclear Science Labs.

    1979-01-01

    Back-scattering of beta rays from /sup 204/Tl (Esub(..beta..)max = 740 keV) and /sup 90/Sr-/sup 90/Y (Esub(..beta..)max =550 and 2250 keV) has been studied in an improved reflection geometry, using annular sources, from a number of elemental targets with Z values ranging from 13 to 82. Source to target and target to detector geometry factors are 0.0225 and 0.0282 respectively. Values of saturation back scattering thickness obtained in the two cases are 72 +- 10 and 190 +- 40 mg/cm/sup 2/ respectively. It is observed that the intensity of back scattered radiation varies linearly with thickness upto a value of 12 +- 2 mg/cm/sup 2/ in /sup 204/Tl and 17 +- 3 mg/cm/sup 2/ in /sup 90/Sr-/sup 90/Y.

  8. Buckling Response of Thick Functionally Graded Plates

    Directory of Open Access Journals (Sweden)

    BOUAZZA MOKHTAR

    2014-11-01

    Full Text Available In this paper, the buckling of a functionally graded plate is studied by using first order shear deformation theory (FSDT. The material properties of the plate are assumed to be graded continuously in the direction of thickness. The variation of the material properties follows a simple power-law distribution in terms of the volume fractions of constituents. The von Karman strains are used to construct the equilibrium equations of the plates subjected to two types of thermal loading, linear temperature rise and gradient through the thickness are considered. The governing equations are reduced to linear differential equation with boundary conditions yielding a simple solution procedure. In addition, the effects of temperature field, volume fraction distributions, and system geometric parameters are investigated. The results are compared with the results of the no shear deformation theory (classic plate theory, CPT.

  9. 30 CFR 816.105 - Backfilling and grading: Thick overburden.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Backfilling and grading: Thick overburden. 816...-SURFACE MINING ACTIVITIES § 816.105 Backfilling and grading: Thick overburden. (a) Definition. Thick... surrounding terrain. (b) Performance standards. Where thick overburden occurs within the permit area, the...

  10. Correlates of eggshell thickness | Okereke | Global Journal of Pure ...

    African Journals Online (AJOL)

    This study discussed the effects of age and genotype of birds and location of farm on eggshell thickness. The ultimate objective of the study is to determine the correlates of eggshell thickness which may be relevant to improve eggshell thickness. Secondary data on eggshell thickness collected from the Agricultural ...

  11. Accelerating Thick Aluminum Liners Using Pulsed Power

    International Nuclear Information System (INIS)

    Kyrala, G.A.; Hammerburg, J.E.; Bowers, D.; Stokes, J.; Morgan, D.V.; Anderson, W.E.; Cochrane, J.C.

    1999-01-01

    The authors have investigated the acceleration of very thick cylindrical aluminum liners using the Pegasus II capacitory bank. These accelerated solid liners will be used to impact other objects at velocities below 1.5 km/sec, allowing one to generate and sustain shocks of a few 100 kilobar for a few microseconds. A cylindrical shell of 1100 series aluminum with an initial inner radius of 23.61 mm, an initial thickness of 3.0 mm, and a height of 20 mm, was accelerated using a current pulse of 7.15 MA peak current and a 7.4 microsecond quarter cycle time. The aluminum shell was imploded within confining copper glide planes with decreasing separation with an inward slope of 8 degrees. At impact with a cylindrical target of diameter 3-cm, the liner was moving at 1.4 km/sec and its thickness increased to 4.5 mm. Radial X-ray radiograms of the liner showed both the liner and the glide plane interface. The curvature of the inner surface of the liner was measured before impact with the 15-mm radius target. The radiograms also showed that the copper glide planes distorted as the liner radius decreased and that some axial stress is induced in the liner. The axial stresses did not affect the inner curvature significantly. Post-shot calculations of the liner behavior indicated that the thickness of the glide plane played a significant role in the distortion of the interface between the liner and the glide plane

  12. A de Sitter tachyon thick braneworld

    Energy Technology Data Exchange (ETDEWEB)

    Germán, Gabriel; Herrera-Aguilar, Alfredo; Malagón-Morejón, Dagoberto [Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apdo. Postal 48-3, 62251, Cuernavaca, Morelos (Mexico); Mora-Luna, Refugio Rigel [Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Ciudad Universitaria, C.P. 58040, Morelia, Michoacán (Mexico); Rocha, Roldão da, E-mail: gabriel@fis.unam.mx, E-mail: aha@fis.unam.mx, E-mail: malagon@ifm.umich.mx, E-mail: rigel@ifm.umich.mx, E-mail: roldao.rocha@ufabc.edu.br [Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, Rua Santa Adélia, 166 09210-170, Santo André, SP (Brazil)

    2013-02-01

    Among the multiple 5D thick braneworld models that have been proposed in the last years, in order to address several open problems in modern physics, there is a specific one involving a tachyonic bulk scalar field. Delving into this framework, a thick braneworld with a cosmological background induced on the brane is here investigated. The respective field equations — derived from the model with a warped 5D geometry — are highly non-linear equations, admitting a non-trivial solution for the warp factor and the tachyon scalar field as well, in a de Sitter 4D cosmological background. Moreover, the non-linear tachyonic scalar field, that generates the brane in complicity with warped gravity, has the form of a kink-like configuration. Notwithstanding, the non-linear field equations restricting character does not allow one to easily find thick brane solutions with a decaying warp factor which leads to the localization of 4D gravity and other matter fields. We derive such a thick brane configuration altogether in this tachyon-gravity setup. When analyzing the spectrum of gravity fluctuations in the transverse traceless sector, the 4D gravity is shown to be localized due to the presence of a single zero mode bound state, separated by a continuum of massive Kaluza-Klein (KK) modes by a mass gap. It contrasts with previous results, where there is a KK massive bound excitation providing no clear physical interpretation. The mass gap is determined by the scale of the metric parameter H. Finally, the corrections to Newton's law in this model are computed and shown to decay exponentially. It is in full compliance to corrections reported in previous results (up to a constant factor) within similar braneworlds with induced 4D de Sitter metric, despite the fact that the warp factor and the massive modes have a different form.

  13. 3D position readout from thick scintillators

    CERN Document Server

    Antich, P; Parkey, R; Slavin, N V; Tsyganov, E N

    2002-01-01

    A novel technique has been developed and tested for the three-dimensional measurement of position in SPECT-PET detectors. Results are presented for 2 and 20 mm thick NaI(Tl) planar crystals. In a plane of crystal, a coordinate resolution of about 1 mm (rms error) is demonstrated. The depth of interaction (DOI) is measured with an rms error of about 2 mm using light cone parameters.

  14. Biocompatible wear-resistant thick ceramic coating

    Directory of Open Access Journals (Sweden)

    Vogt Nicola

    2016-09-01

    Full Text Available Sensitisation to immunologically active elements like chromium, cobalt or nickel and debris particle due to wear are serious problems for patients with metallic implants. We tested the approach of using a hard and thick ceramic coating as a wear-resistant protection of titanium implants, avoiding those sensitisation and foreign body problems. We showed that the process parameters strongly influence the coating porosity and, as a consequence, also its hardness.

  15. CO2 Selective Potentiometric Sensor in Thick-film Technology

    Directory of Open Access Journals (Sweden)

    Ralf Moos

    2008-08-01

    Full Text Available A potentiometric sensor device based on screen-printed Nasicon films was investigated. In order to transfer the promising sensor concept of an open sodium titanate reference to thick film technology, “sodium-rich” and “sodium-poor” formulations were compared. While the “sodium-rich” composition was found to react with the ion conducting Nasicon during thermal treatment, the “sodium-poor” reference mixture was identified as an appropriate reference composition. Screen-printed sensor devices were prepared and tested with respect to CO2 response, reproducibility, and cross-interference of oxygen. Excellent agreement with the theory was observed. With the integration of a screen-printed heater, sensor elements were operated actively heated in a cold gas stream.

  16. Fast synthesis, formation mechanism, and control of shell thickness of CuS–polystyrene core–shell microspheres

    International Nuclear Information System (INIS)

    Zhao, Li-min; Shao, Xin; Yin, Yi-bin; Li, Wen-zhi

    2012-01-01

    Graphical abstract: Core–shell structure PSt/CuS were prepared using polystyrene which were modified by 3-methacryloxypropyltrimethoxysilane as template. The coating thickness of CuS can be controlled by the amount of 3-methacryloxypropyltrimethoxysilane and the UV–vis absorption intensity of PSt/CuS composite also changed with the coating thickness of CuS. Highlights: ► Core–shell structure PSt/CuS were prepared using silanol-modified polystyrene microspheres as template. ► The coating thickness of core–shell structure PSt/CuS can be controlled by a simple method. ► The UV–vis absorption intensity of PSt/CuS composite also changed with the coating thickness of CuS. -- Abstract: The silanol-modified polystyrene microspheres were prepared through dispersion polymerization. Then copper sulfide particles were grown on silanol-modified polystyrene through sonochemical deposition in an aqueous bath containing copper acetate and sulfide, released through the hydrolysis of thioacetamide. The resulting particles were continuous and uniform as characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Fourier transform infrared, thermogravimetric analysis and UV–vis absorption spectroscopy were used to characterize the structure and properties of core–shell particles. The results showed the coating thickness of CuS shell can be controlled by the amount of silanol and the UV–vis absorption intensity of PSt/CuS composite also changed with the coating thickness of CuS.

  17. Determination of the coating base thickness with beta backscattering gauges

    International Nuclear Information System (INIS)

    Krejndlin, I.I.; Novikov, V.S.; Pravikov, A.A.

    1976-01-01

    In using beta thickness meters for coating examination, it is necessary that the substrate thickness be greater or equal to the saturation thickness for which one can neglect a systematic error caused by substrate thickness variation. A formula is derived and nomograms are presented for the determination of the substrate saturation thickness with the account of factors affecting the results of coating thickness measurement. The results of saturation thickness calculation are tabulated for a number of substrate materials with using different β-sources ( 147 Pm, 85 Kr, 90 Sr+ 90 Y)

  18. Factors Affecting the Thickness of Thermal Aureoles

    Directory of Open Access Journals (Sweden)

    Catherine Annen

    2017-10-01

    Full Text Available Intrusions of magma induce thermal aureoles in the country rock. Analytical solutions predict that the thickness of an aureole is proportional to the thickness of the intrusion. However, in the field, thermal aureoles are often significantly thinner or wider than predicted by simple thermal models. Numerical models show that thermal aureoles are wider if the heat transfer in the magma is faster than in the country rock due to contrasts in thermal diffusivities or the effect of magma convection. Large thermal aureoles can also be caused by repeated injection close to the contact. Aureoles are thin when heat transfer in the country rock is faster than heat transfer within the magma or in case of incrementally, slowly emplaced magma. Absorption of latent heat due to metamorphic reactions or water volatilization also affects thermal aureoles but to a lesser extent. The way these parameters affect the thickness of a thermal aureole depends on the isotherm under consideration, hence on which metamorphic phase is used to draw the limit of the aureole. Thermal aureoles provide insight on the dynamics of intrusions emplacement. Although available examples are limited, asymmetric aureoles point to magma emplacement by over-accretion for mafic cases and by under-accretion for felsic cases, consistent with geochronological data.

  19. Nano-Hydroxyapatite Thick Film Gas Sensors

    International Nuclear Information System (INIS)

    Khairnar, Rajendra S.; Mene, Ravindra U.; Munde, Shivaji G.; Mahabole, Megha P.

    2011-01-01

    In the present work pure and metal ions (Co and Fe) doped hydroxyapatite (HAp) thick films have been successfully utilized to improve the structural, morphological and gas sensing properties. Nanocrystalline HAp powder is synthesized by wet chemical precipitation route, and ion exchange process is employed for addition of Co and Fe ions in HAp matrix. Moreover, swift heavy ion irradiation (SHI) technique is used to modify the surface of pure and metal ion exchanged HAp with various ion fluence. The structural investigation of pure and metal ion exchanged HAp thick films are carried out using X-ray diffraction and the presence of functional group is observed by means FTIR spectroscopy. Furthermore, surface morphology is visualized by means of SEM and AFM analysis. CO gas sensing study is carried out for, pure and metal ions doped, HAp thick films with detail investigation on operating temperature, response/recovery time and gas uptake capacity. The surface modifications of sensor matrix by SHI enhance the gas response, response/recovery and gas uptake capacity. The significant observation is here to note that, addition of Co and Fe in HAp matrix and surface modification by SHI improves the sensing properties of HAp films drastically resulting in gas sensing at relatively lower temperatures.

  20. Macular thickness after glaucoma filtration surgery.

    Science.gov (United States)

    Sesar, Antonio; Cavar, Ivan; Sesar, Anita Pusić; Geber, Mia Zorić; Sesar, Irena; Laus, Katia Novak; Vatavuk, Zoran; Mandić, Zdravko

    2013-09-01

    The aim of present study was to analyze early postoperative changes in the macular area using optical coherence tomography (OCT) after uncomplicated glaucoma filtration surgery. This prospective study included 32 patients (34 eyes) with open-angle glaucoma, which underwent trabeculectomy with or without use of mitomycin C. Exclusion criteria were macular edema, uveitis, age-related macular degeneration, blurred optical media, secondary glaucoma and angle-closure glaucoma. All standard clinical examinations were made before surgery, at the 2nd day, 1 week and 1 month after surgery. Tomography of the macula was performed during every examination using Cirrus HD OCT for the analysis of central subfield thickness. Results show that thickening of the macula was slightly higher 1 week and 1 month after operation in comparison with baseline end 2nd day postoperativelly. There was no significant difference in the change of macular thickness in patients who have used topical prostaglandins compared with those who have used other topical medications. Also, there was no difference in macular changes between patients treated with or without mitomycin C. In conclusion, we found a slight subclinical increase in macular thickness after uncomplicated trabeculectomy, for which we considered that was the result in reduction of intraocular pressure after glaucoma surgery. Macular thickening after glaucoma filtering surgery could be a physiological reaction to the stress of the retina caused by a sudden reduction of intraocular pressure and it is the consequence of altered relationship between capillary pressure and interstitial fluid pressure.

  1. Hexaferrite multiferroics: from bulk to thick films

    Science.gov (United States)

    Koutzarova, T.; Ghelev, Ch; Peneva, P.; Georgieva, B.; Kolev, S.; Vertruyen, B.; Closset, R.

    2018-03-01

    We report studies of the structural and microstructural properties of Sr3Co2Fe24O41 in bulk form and as thick films. The precursor powders for the bulk form were prepared following the sol-gel auto-combustion method. The prepared pellets were synthesized at 1200 °C to produce Sr3Co2Fe24O41. The XRD spectra of the bulks showed the characteristic peaks corresponding to the Z-type hexaferrite structure as a main phase and second phases of CoFe2O4 and Sr3Fe2O7-x. The microstructure analysis of the cross-section of the bulk pellets revealed a hexagonal sheet structure. Large areas were observed of packages of hexagonal sheets where the separate hexagonal particles were ordered along the c axis. Sr3Co2Fe24O41 thick films were deposited from a suspension containing the Sr3Co2Fe24O41 powder. The microstructural analysis of the thick films showed that the particles had the perfect hexagonal shape typical for hexaferrites.

  2. Universal Rim Thickness in Unsteady Sheet Fragmentation

    Science.gov (United States)

    Wang, Y.; Dandekar, R.; Bustos, N.; Poulain, S.; Bourouiba, L.

    2018-05-01

    Unsteady fragmentation of a fluid bulk into droplets is important for epidemiology as it governs the transport of pathogens from sneezes and coughs, or from contaminated crops in agriculture. It is also ubiquitous in industrial processes such as paint, coating, and combustion. Unsteady fragmentation is distinct from steady fragmentation on which most theoretical efforts have been focused thus far. We address this gap by studying a canonical unsteady fragmentation process: the breakup from a drop impact on a finite surface where the drop fluid is transferred to a free expanding sheet of time-varying properties and bounded by a rim of time-varying thickness. The continuous rim destabilization selects the final spray droplets, yet this process remains poorly understood. We combine theory with advanced image analysis to study the unsteady rim destabilization. We show that, at all times, the rim thickness is governed by a local instantaneous Bond number equal to unity, defined with the instantaneous, local, unsteady rim acceleration. This criterion is found to be robust and universal for a family of unsteady inviscid fluid sheet fragmentation phenomena, from impacts of drops on various surface geometries to impacts on films. We discuss under which viscous and viscoelastic conditions the criterion continues to govern the unsteady rim thickness.

  3. Precision of hyaline cartilage thickness measurements

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, K.; Buckwalter, K.; Helvie, M.; Niklason, L.; Martel, W. (Univ. of Michigan Hospitals, Ann Arbor, MI (United States). Dept. of Radiology)

    1992-05-01

    Measurement of cartilage thickness in vivo is an important indicator of the status of a joint as the various degenerative and inflammatory arthritides directly affect the condition of the cartilage. In order to assess the precision of thickness measurements of hyaline articular cartilage, we undertook a pilot study using MR imaging, plain radiography, and ultrasonography (US). We measured the cartilage of the hip and knee joints in 10 persons (4 healthy volunteers and 6 patients). The joints in each patient were examined on two separate occasions using each modality. In the hips a swell as the knee joints, the most precise measuring method was plain film radiography. For radiographs of the knees obtained in the standing position, the coefficient of variation was 6.5%; in the hips this figure was 6.34%. US of the knees and MR imaging of the hips were the second best modalities in the measurement of cartilage thickness. In addition, MR imaging enabled the most complete visualization of the joint cartilage. (orig.).

  4. A thick placenta: a predictor of adverse pregnancy outcomes.

    Science.gov (United States)

    Miwa, Ichiro; Sase, Masakatsu; Torii, Mayumi; Sanai, Hiromi; Nakamura, Yasuhiko; Ueda, Kazuyuki

    2014-01-01

    The aim of this study is to evaluate the efficacy of an ultrasonographic measurement of placental thickness and the correlation of a thick placenta with adverse perinatal outcome. Placental thickness was measured in single gravidas, 16 to 40 weeks of gestation, between 2005 and 2009. Placentas were considered to be thick if their measured thickness were above the 95th percentile for gestational age. The incidence of thick placentas was 4.3% (138/3,183). Perinatal morbidity and neonatal conditions were worse in cases with thick placenta rather than without thick placenta. Ultrasonographic measurement of placental thickness is a simple method to estimate placental size. Thick placenta may be a useful predictor of adverse pregnancy outcomes.

  5. Cranial vault thickness in primates: Homo erectus does not have uniquely thick vault bones.

    Science.gov (United States)

    Copes, Lynn E; Kimbel, William H

    2016-01-01

    Extremely thick cranial vaults have been noted as a diagnostic characteristic of Homo erectus since the first fossil of the species was identified, but relatively little work has been done on elucidating its etiology or variation across fossils, living humans, or extant non-human primates. Cranial vault thickness (CVT) is not a monolithic trait, and the responsiveness of its layers to environmental stimuli is unknown. We obtained measurements of cranial vault thickness in fossil hominins from the literature and supplemented those data with additional measurements taken on African fossil specimens. Total CVT and the thickness of the cortical and diploë layers individually were compared to measures of CVT in extant species measured from more than 500 CT scans of human and non-human primates. Frontal and parietal CVT in fossil primates was compared to a regression of CVT on cranial capacity calculated for extant species. Even after controlling for cranial capacity, African and Asian H. erectus do not have uniquely high frontal or parietal thickness residuals, either among hominins or extant primates. Extant primates with residual CVT thickness similar to or exceeding H. erectus (depending on the sex and bone analyzed) include Nycticebus coucang, Perodicticus potto, Alouatta caraya, Lophocebus albigena, Galago alleni, Mandrillus sphinx, and Propithecus diadema. However, the especially thick vaults of extant non-human primates that overlap with H. erectus values are composed primarily of cortical bone, while H. erectus and other hominins have diploë-dominated vault bones. Thus, the combination of thick vaults comprised of a thickened diploë layer may be a reliable autapomorphy for members of the genus Homo. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Wood composites

    Science.gov (United States)

    Lars Berglund; Roger M. Rowell

    2005-01-01

    A composite can be defined as two or more elements held together by a matrix. By this definition, what we call “solid wood” is a composite. Solid wood is a three-dimensional composite composed of cellulose, hemicelluloses and lignin (with smaller amounts of inorganics and extractives), held together by a lignin matrix. The advantages of developing wood composites are (...

  7. The optimum lead thickness for lead-activation detectors

    International Nuclear Information System (INIS)

    Si Fenni; Hu Qingyuan

    2009-01-01

    The optimum lead thickness for lead-activation detectors has been studied in this paper. First existence of the optimum lead thickness is explained theoretically. Then the optimum lead thickness is obtained by two methods, MCNP5 calculation and mathematical estimation. At last factors which affect the optimum lead thickness are discussed. It turns out that the optimum lead thickness is irrelevant to incident neutron energies. It is recommended 2.5 cm generally.

  8. Thick vortices in SU(2) lattice gauge theory

    OpenAIRE

    Cheluvaraja, Srinath

    2004-01-01

    Three dimensional SU(2) lattice gauge theory is studied after eliminating thin monopoles and the smallest thick monopoles. Kinematically this constraint allows the formation of thick vortex loops which produce Z(2) fluctuations at longer length scales. The thick vortex loops are identified in a three dimensional simulation. A condensate of thick vortices persists even after the thin vortices have all disappeared. The thick vortices decouple at a slightly lower temperature (higher beta) than t...

  9. Correlation between choroidal thickness and macular hole

    Directory of Open Access Journals (Sweden)

    Li-Li Wang

    2018-01-01

    Full Text Available AIM:To explore the correlation between choroidal thickness and macular hole, and to provide a theoretical basis for diagnosis and treatment of macular hole. METHODS: This study included 40 cases of monocular idiopathic macular hole patients who were treated in ophthalmology of our hospital from June 2015 to June 2016 and 40 cases of healthy people. Sicked eyes of idiopathic macular hole patients(40 eyeswere set as the Group A, uninjured side eyes(40 eyeswere set as the Group B, eyes of 40 cases of healthy people(40 normal eyeswere set as the Group C. Choroidal thickness of macular fovea, macular fovea 1mm, 3mm at 9 points, 4 directions in the upper, lower, nasal and temporal regions were measured through coherent optical tomography of enhanced deep imaging(enhanced depth image optical coherence tomography, EDI-OCT. They were recorded as SFCT, SCT1mm, SCT3mm, ICT1mm, ICT3mm, NCT1mm, NCT3mm, TCT1mm, TCT3mm, and correlation analysis between SFCT and age was analyzed. RESULTS: Average SFCT of Group A, B had no significant difference, data of the Group C was significantly higher than those of the Group A, B, there was statistical significance(P1mm, SCT3mm, ICT1mm, ICT3mm, NCT1mm, NCT3mm, TCT1mm, TCT3mm of the Group A, B had no significant difference(P>0.05, and choroidal thickness at each point of the Group C was significantly higher than that of Group A and B, there was statistical significance(Pr=-0.065, P=0.148; r=-0.057, P=0.658, SFCT of the Group C was negatively correlated with age(r=-0.343, P=0.041. CONCLUSION: The pathogenesis of idiopathic macular hole may be related to the sharp decrease of choroidal thickness, choroidal thickness of uninjured side eyes reduces more sharply than normal population and choroidal vascular metabolism reduces may be pathogenic.

  10. Analysis of Different Positions of Fiber-Reinforced Composite Retainers versus Multistrand Wire Retainers Using the Finite Element Method

    Directory of Open Access Journals (Sweden)

    Arezoo Jahanbin

    2014-01-01

    Full Text Available Background. The aim of this study was to evaluate root displacement of the lower incisors fixed with FRC in different positions versus FSW retainers using the finite element method. Materials and Methods. 3D finite element models were designed for a mandibular anterior segment: Model 1: flexible spiral wire bonded to the lingual teeth surfaces, Model 2: FRC bonded to the upper third of lingual teeth surfaces, and Model 3: FRC bonded to the middle third. FE analysis was performed for three models and then tooth displacements were evaluated. Results. In contrast to lateral incisors and canines, the FSW retainer caused the central teeth to move more than the teeth bonded with FRC in both loadings. Comparison between Models 2 and 3 (in vertical loading showed that FRC retainers that bonded at the upper third of lingual teeth surfaces made central and canine teeth move less than FRC retainers bonded at the middle third; however, for lateral teeth it was the opposite. Conclusion. FRC retainers bonded at the upper third of lingual teeth surfaces make central and canine teeth move less than FRC retainers bonded at the middle third in vertical loading; however, for lateral teeth it was the opposite.

  11. Photoluminescence from ZnO-SiO2 opals with different sphere diameters and thicknesses

    International Nuclear Information System (INIS)

    Yang Yingling; Yan Hongwei; Fu Zhengping; Yang Beifang; Xia Linsheng; Wang Zhen; Zuo Jian; Yu Shijun; Fu Shengquan; Li Fanqing

    2007-01-01

    We systematically investigated the photoluminescence (PL) and transmittance characteristics of ZnO-SiO 2 opals with varied positions of the stop-band and film thicknesses. An improved ultraviolet (UV) luminescence was observed from ZnO-SiO 2 composites over pure ZnO nanocrystals under 325 nm He-Cd laser excitation at room temperature. The UV PL of ZnO nanocrystals in SiO 2 opals with stop-bands center of 410 nm is sensitive to the thickness of opal films, and the UV PL intensity increases with the film thickness increasing. The PL spectra of ZnO nanocrystals in SiO 2 opals with stop-bands center of 570 nm show a suppression of the weak visible band. The experimental results are discussed based on the scattering and/or absorbance in opal crystals

  12. Estimation of critical thickness of Stranski-Krastanow transition in GeSi/Sn/Si system

    Science.gov (United States)

    Lozovoy, K. A.; Pishchagin, A. A.; Kokhanenko, A. P.; Voitsekhovskii, A. V.

    2017-11-01

    In this paper Stranski-Krastanow growth of Ge x Si1-x epitaxial layers on the Si(001) surface with pre-deposited tin layer with the thickness less than 1 ML is considered. For the calculations of critical thickness of transition from 2D to 3D growth in this paper a theoretical model based on general nucleation theory is used. This model is specified by taking into account dependencies of elastic modulus, lattices mismatch and surface energy of side facet on the composition x, as well as change in the adatoms diffusion coefficient and surface energy of the substrate in the presence of tin. As a result, dependencies of critical thickness of Stranski-Krastanow transition on compositon x and temperature are obtained. The simulated results are in a good agreement with experimentally observed results.

  13. Micro-machined high-frequency (80 MHz) PZT thick film linear arrays.

    Science.gov (United States)

    Zhou, Qifa; Wu, Dawei; Liu, Changgeng; Zhu, Benpeng; Djuth, Frank; Shung, K

    2010-10-01

    This paper presents the development of a micromachined high-frequency linear array using PZT piezoelectric thick films. The linear array has 32 elements with an element width of 24 μm and an element length of 4 mm. Array elements were fabricated by deep reactive ion etching of PZT thick films, which were prepared from spin-coating of PZT sol-gel composite. Detailed fabrication processes, especially PZT thick film etching conditions and a novel transferring-and-etching method, are presented and discussed. Array designs were evaluated by simulation. Experimental measurements show that the array had a center frequency of 80 MHz and a fractional bandwidth (-6 dB) of 60%. An insertion loss of -41 dB and adjacent element crosstalk of -21 dB were found at the center frequency.

  14. Prediction of Layer Thickness in Molten Borax Bath with Genetic Evolutionary Programming

    Science.gov (United States)

    Taylan, Fatih

    2011-04-01

    In this study, the vanadium carbide coating in molten borax bath process is modeled by evolutionary genetic programming (GEP) with bath composition (borax percentage, ferro vanadium (Fe-V) percentage, boric acid percentage), bath temperature, immersion time, and layer thickness data. Five inputs and one output data exist in the model. The percentage of borax, Fe-V, and boric acid, temperature, and immersion time parameters are used as input data and the layer thickness value is used as output data. For selected bath components, immersion time, and temperature variables, the layer thicknesses are derived from the mathematical expression. The results of the mathematical expressions are compared to that of experimental data; it is determined that the derived mathematical expression has an accuracy of 89%.

  15. Effect of Accelerated Aging on Color Change of Direct and Indirect Fiber-Reinforced Composite Restorations

    Directory of Open Access Journals (Sweden)

    Masomeh Hasani Tabatabaei

    2016-10-01

    Full Text Available Objectives: The aim of this study was to assess the effect of artificial accelerated aging (AAA on color change of direct and indirect fiber-reinforced composite (FRC restorations.Materials and Methods: Direct (Z250 and indirect (Gradia composite resins were reinforced with glass (GF and polyethylene fibers (PF based on the manufacturers’ instructions. Forty samples were fabricated and divided into eight groups (n=5. Four groups served as experimental groups and the remaining four served as controls. Color change (∆E and color parameters (∆L*, ∆a*, ∆b* were read at baseline and after AAA based on the CIELAB system. Three-way ANOVA and Tukey’s test were used for statistical analysis.Results: Significant differences were found in ΔE, ΔL*, Δa* and Δb* among the groups after AAA (P<0.05. Most of the studied samples demonstrated an increase in lightness and a red-yellow shift after AAA.Conclusions: The obtained ∆E values were unacceptable after AAA (∆E≥ 3.3. All indirect samples showed a green-blue shift with a reduction in lightness except for Gradia/PF+ NuliteF.Keywords: Aging; Composite Resins; Color

  16. Study of the mechanical properties of Ziziphus nummularia (ber) fibers for formation of fiber reinforced composites

    Science.gov (United States)

    Joshi, Akshay; Mangal, R.; Bhojak, N.

    2018-05-01

    Ziziphus is the one of the most abundant plant of arid region of Rajasthan and rest part of desert land in world. There are a lots of research work going on and has been done on medical applications of this plant and it is playing very important role in economy of desert areas. In this paper our discussion will bring the attention its physical properties so that we can find the possibility of its applications in the various field of fiber reinforced composites which either can be used in such as interior & exterior part of automotive so it can reduce their overall weight, cost and improve its fuel efficiency without compromising in strength or can be used in flywheel technology for energy saving in automobiles or in building materials and so on. In this paper our approach is to extract the fiber from this plant, analyze the mechanical properties of the fiber and then discuss the various possibility of its application in appropriate field of composites. To find the possibility in FRC for Ziziphus fiber our next step is to compare it with other fibers whose composites have already been formed and studied.

  17. Enhanced impact properties of cementitious composites reinforced with pultruded flax/polymeric matrix fabric

    Directory of Open Access Journals (Sweden)

    Magdi El-Messiry

    2017-09-01

    Full Text Available Fiber reinforced concrete (FRC has become increasingly applied in civil engineering in the last decades. Natural fiber fabric reinforced cement composites are considered to prevent damage resulting from an impact loading on the cementite plate. Flax woven fabric that has a high energy absorption capability was chosen. To increase the interfacial shear properties, the fabric was pultruded with different matrix properties that affect the strength and toughness of the pultruded fabric. In this study, three fabric structures are used to increase the anchoring of the cement in the fabric. The compressive strength and the impact energy were measured. The results revealed that pultruded fabric reinforced cement composite (PFRC absorbs much more impact energy. PFRC under impact loading has more micro cracks, while plain cement specimen shows brittle failure. The compressive test results of PFRC indicate that flax fiber fabric polymer enhanced compressive strength remarkably. Fiber reinforcement is a very effective in improving the impact resistance of PFRC. The study defines the influence factors that control the energy dissipation of the composite, which are the hardness of the polymer and the fabric cover factor. Significant correlation between impact energy and compressive strength was proved.

  18. Effect of coping thickness and background type on the masking ability of a zirconia ceramic.

    Science.gov (United States)

    Tabatabaian, Farhad; Taghizade, Fateme; Namdari, Mahshid

    2018-01-01

    The masking ability of zirconia ceramics as copings is unclear. The purpose of this in vitro study was to evaluate the effect of coping thickness and background type on the masking ability of a zirconia ceramic and to determine zirconia coping thickness cut offs for masking the backgrounds investigated. Thirty zirconia disks in 3 thickness groups of 0.4, 0.6, and 0.8 mm were placed on 9 backgrounds to measure CIELab color attributes using a spectrophotometer. The backgrounds included A1, A2, and A3.5 shade composite resin, A3 shade zirconia, nickel-chromium alloy, nonprecious gold-colored alloy, amalgam, black, and white. ΔE values were measured to determine color differences between the specimens on the A2 shade composite resin background and the same specimens on the other backgrounds. The color change (ΔE) values were compared with threshold values for acceptability (ΔE=5.5) and perceptibility (ΔE=2.6). Repeated measures ANOVA, the Bonferroni test, and 1-sample t tests were used to analyze data (α=.05). Mean ΔE values ranged between 1.44 and 7.88. The zirconia coping thickness, the background type, and their interaction affected the CIELab and ΔE values (Pmasking, the minimum thickness of a zirconia coping should be 0.4 mm for A1 and A3.5 shade composite resin, A3 shade zirconia, and nonprecious gold-colored alloy, 0.6 mm for amalgam, and 0.8 mm for nickel-chromium alloy. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  19. Composite shade guides and color matching.

    Science.gov (United States)

    Paolone, Gaetano; Orsini, Giovanna; Manauta, Jordi; Devoto, Walter; Putignano, Angelo

    2014-01-01

    Finding reliable systems that can help the clinician match the color of direct composite restorations is often an issue. After reviewing several composite shade guides available on the market and outlining their main characteristics and limits (unrealistic specimen thickness, not made with the same material the clinician will use, only a few allow to overlap enamel tabs on dentin ones), the authors evaluated the reliability of a system designed to produce self-made standardized "tooth-shaped" shade guide specimens. Small changes in composite enamel thickness may determine huge differences in esthetic outcomes. In conclusion, the results showed that all the specimens demonstrated comparable enamel thickness in all the examined areas (cervical, middle, incisal).

  20. Uncertainties of the ultrasonic thickness gauging (UTTG)

    International Nuclear Information System (INIS)

    Mohamad Pauzi Ismail; Yassir Yassen; Amry Amin Abas

    2009-04-01

    The reliability of UTTG was questioned by a senior staff from DOSH in his paper presented during third NDT and Corrosion Management Asia Conference and Exhibition, 4-5 September 2007 at Istana Hotel, Kuala Lumpur. A term 'thickness grow' is an issue need to be solved by NDT community. The technique used by many practitioners gives rise to serious shortcoming in both probability of detection and accuracy of remaining wall assessment. This paper explained and discussed on uncertainty measurement based on the ISO Guide to the Expression of Uncertainty in Measurement (GUM) (1) of real UTTG data obtained from chemical industry. (author)

  1. Skin thickness effects on in vivo LXRF

    International Nuclear Information System (INIS)

    Preiss, I.L.; Washington, W. II

    1995-01-01

    The analysis of lead concentration in bone utilizing LXRF can be adversely effected by overlying issue. A quantitative measure of the attenuation of the 10.5 keV Pb L a x-ray signal by skin and skin equivalent plastic has been conducted. Concentration ranges in plaster of Paris and goat bone from 7 to 90 ppm with attenuators of Lucite reg-sign and pig skin were examined. It is concluded that no quantitative or semi quantitative analysis can be achieved if overlying sue thickness exceeds 3 mm for Ph concentrations of less than 30 porn Ph in bone

  2. Full-thickness endometriosis of the bladder

    DEFF Research Database (Denmark)

    Kjer, Jens Jørgen; Kristensen, Jens; Hartwell, Dorthe

    2014-01-01

    referral centres in Denmark for surgical treatment of stage III and IV endometriosis. POPULATION: Thirty-one women with deep infiltrating bladder endometriosis. METHODS: All women presenting in the Department of Obstetrics and Gynaecology with deep infiltrating bladder endometriosis between March 2002...... and March 2011. We included only patients with symptomatic full-thickness bladder detrusor endometriosis and mucosal involvement. All patients had had bladder symptoms for two to seven years. MAIN OUTCOME MEASURES: Symptoms after surgery and recurrence rate. RESULTS: The main preoperative symptom...

  3. Cement thickness measurements in cased boreholes

    International Nuclear Information System (INIS)

    Wahl, J.S.; Schuster, N.A.

    1978-01-01

    Methods and apparatus are provided for logging a borehole having solid matter along at least a portion of the wall thereof. Gamma radiation is emitted from the borehole into the surrounding media, and the amount of radiation which returns to the borehole is measured by three detectors located at different distances from the source of radiation, so as to be primarily sensitive to radiation which has respectively penetrated to three different depths in the surrounding media. The thickness of the solid matter on the borehole wall is then determined from the three gamma radiation measurements

  4. Endoscopic full-thickness resection: Current status.

    Science.gov (United States)

    Schmidt, Arthur; Meier, Benjamin; Caca, Karel

    2015-08-21

    Conventional endoscopic resection techniques such as endoscopic mucosal resection or endoscopic submucosal dissection are powerful tools for treatment of gastrointestinal neoplasms. However, those techniques are restricted to superficial layers of the gastrointestinal wall. Endoscopic full-thickness resection (EFTR) is an evolving technique, which is just about to enter clinical routine. It is not only a powerful tool for diagnostic tissue acquisition but also has the potential to spare surgical therapy in selected patients. This review will give an overview about current EFTR techniques and devices.

  5. Natural frequencies and an atlas of mode shapes for generally-laminated, thick, skew, trapezoidal plates

    OpenAIRE

    Lovejoy, Andrew Elwyn

    1994-01-01

    Composite materials are increasingly finding use in structures, such as aircraft components, and thus, an accurate method of predicting response is required. Even laminated structures that are considered thin can be significantly affected by transverse shear effects, and as a result, transverse shear should not be neglected. The free vibration response of generally-laminated, thick, skew, trapezoidal plates is investigated as there appears to be a lack of information in this ar...

  6. Application of Industrial XRF Coating Thickness Analyzer for Phosphate Coating Thickness on Steel

    Directory of Open Access Journals (Sweden)

    Aleksandr Sokolov

    2018-03-01

    Full Text Available The results of industrial application of an online X-ray fluorescence coating thickness analyzer for measuring the thickness of phosphate coatings on moving steel strips are considered in the article. The target range of coating thickness to be measured is from tens to hundreds of mg/m2 in a measurement time of 10 s. The measurement accuracy observed during long-duration factory acceptance test was 10–15%. The coating thickness analyzer consists of two XRF gauges, mounted above and below the steel strip and capable of moving across the moving strip system for their suspension and relocation and electronic control unit. Fully automated software was developed to automatically and continuously (24/7 control both gauges, scanning both sides of the steel strip, and develop and test methods for measuring new coatings. It allows performing offline storage and retrieval of the measurement results, remotely controlling the analyzer components and measurement modes from a control room. The developed XRF coating thickness analyzer can also be used for real-time measurement of other types of coatings, both metallic and non-metallic.

  7. Cutting work in thick section cryomicrotomy.

    Science.gov (United States)

    Saubermann, A J; Riley, W D; Beeuwkes, R

    1977-09-01

    The forces during cryosectioning were measured using miniature strain gauges attached to a load cell fitted to the drive arm of the Porter-Blum MT-2 cryomicrotome. Work was calculated and the data normalized to a standard (1 mm X 1 mm X 0.5 micrometer) section. Thermal energy generated was also calculated. Five parameters were studied: cutting angle, thickness, temperature, hardness, and block shape. Force patterns could be divided into three major groups thought to represent cutting (Type I), large fracture planes greater than 10 micrometer in length (Type II), and small fracture planes less than 10 micrometer in length (Type III). Type I and Type II produced satisfactory sections. Work in cutting ranged from an average of 78.4 muJ to 568.8 muJ. Cutting angle and temperature had the greatest effect on sectioning. Heat generated would be sufficient to cause through-section melting for 0.5 micrometer thick sections assuming the worst possible case, namely that all heat went into the section without loss. Presence of a Type II pattern (large fracture pattern) is thought to be presumptive evidence against thawing.

  8. New portable pipe wall thickness measuring technique

    Science.gov (United States)

    Pascente, Joseph E.

    1998-03-01

    One of the biggest inspection challenges facing many of the process industries; namely the petrochemical, refining, fossil power, and pulp and paper industries is: How to effectively examine their insulated piping? While there are a number of failure mechanisms involved in various process piping systems, piping degradation through corrosion and erosion are by far the most prevalent. This degradation can be in the form of external corrosion under insulation, internal corrosion through a variety of mechanisms, and internal erosion caused by the flow of the product through the pipe. Refineries, chemical plants and electrical power plants have MANY thousands of miles of pipe that are insulated to prevent heat loss or heat absorption. This insulation is often made up of several materials, with calcium based material being the most dense. The insulating material is usually wrapped with an aluminum or stainless steel outer wrap. Verification of wall thickness of these pipes can be accomplished by removing the insulation and doing an ultrasound inspection or by taking x- rays at a tangent to the edge of the pipe through the insulation. Both of these processes are slow and expensive. The time required to obtain data is measured in hours per meter. The ultrasound method requires that the insulation be plugged after the inspection. The surface needs to be cleaned or the resulting data will not be accurate. The tangent x-ray only shows two thicknesses and requires that the area be roped off because of radiation safety.

  9. Cortical Thickness Changes Associated with Photoparoxysmal Response

    DEFF Research Database (Denmark)

    Hanganu, Alexandru; Groppa, Stanislav A; Deuschl, Günther

    2014-01-01

    Photoparoxysmal response (PPR) is an EEG trait of spike and spike-wave discharges in response to photic stimulation that is closely linked to idiopathic generalized epilepsy (IGE). In our previous studies we showed that PPR is associated with functional alterations in the occipital and frontal co...... in the occipital lobe, frontoparietal regions and temporal lobe, which also show functional changes associated with PPR. Patients with epilepsy present changes in the temporal lobe and supplementary motor area.......-positive-subjects presented a significant decrease of cortical thickness in the temporal cortex in the same group contrast. IGE patients exhibited lower cortical thickness in the temporal lobe bilaterally and in the right paracentral region in comparison to PPR-positive-subjects. Our study demonstrates structural changes......Photoparoxysmal response (PPR) is an EEG trait of spike and spike-wave discharges in response to photic stimulation that is closely linked to idiopathic generalized epilepsy (IGE). In our previous studies we showed that PPR is associated with functional alterations in the occipital and frontal...

  10. Thick or Thin Ice Shell on Europa?

    Science.gov (United States)

    2007-01-01

    Scientists are all but certain that Europa has an ocean underneath its icy surface, but they do not know how thick this ice might be. This artist concept illustrates two possible cut-away views through Europa's ice shell. In both, heat escapes, possibly volcanically, from Europa's rocky mantle and is carried upward by buoyant oceanic currents. If the heat from below is intense and the ice shell is thin enough (left), the ice shell can directly melt, causing what are called 'chaos' on Europa, regions of what appear to be broken, rotated and tilted ice blocks. On the other hand, if the ice shell is sufficiently thick (right), the less intense interior heat will be transferred to the warmer ice at the bottom of the shell, and additional heat is generated by tidal squeezing of the warmer ice. This warmer ice will slowly rise, flowing as glaciers do on Earth, and the slow but steady motion may also disrupt the extremely cold, brittle ice at the surface. Europa is no larger than Earth's moon, and its internal heating stems from its eccentric orbit about Jupiter, seen in the distance. As tides raised by Jupiter in Europa's ocean rise and fall, they may cause cracking, additional heating and even venting of water vapor into the airless sky above Europa's icy surface. (Artwork by Michael Carroll.)

  11. Composite Materials

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    This book deals with the mechanical and physical behavior of composites as influenced by composite geometry. "Composite Materials" provides a comprehensive introduction for researchers and students to modern composite materials research with a special emphasis on the significance of phase geometry......, viscoelastic behavior, and internal stress states. Other physical properties considered are thermal and electrical conductivities, diffusion coefficients, dielectric constants and magnetic permeability. Special attention is given to the effect of pore shape on the mechanical and physical behavior of porous....... The book enables the reader to a better understanding of the behavior of natural composites, improvement of such materials, and design of new materials with prescribed properties. A number of examples are presented: Special composite properties considered are stiffness, shrinkage, hygro-thermal behavior...

  12. Smart carbon nanotube/fiber and PVA fiber-reinforced composites for stress sensing and chloride ion detection

    Science.gov (United States)

    Hoheneder, Joshua

    Fiber reinforced composites (FRC) with polyvinyl alcohol (PVA) fibers and carbon nanofibers (CNF) had an excellent flexural strength in excess of 18.5 MPa compared to reference samples of 15.8 MPa. It was found that the developed, depending on applied stress and exposure to chloride solutions, composites exhibit some electrical conductivity, from 4.20×10 -4 (Ω-1m-1 to 4.13×10 -4 Ω-1m-1. These dependences can be characterized by piezioresistive and chemoresistive coefficients demonstrating that the material possesses self-sensing capabilities. The sensitivity to stain and chloride solutions can be enhanced by incorporating small amounts of carbon nanofibers (CNF) or carbon nanotube (CNT) into composite structure. Conducted research has demonstrated a strong dependency of electrical properties of composite on crack formation in moist environments. The developed procedure is scalable for industrial application in concrete structures that require nondestructive stress monitoring, integrity under high service loads and stability in harsh environments.

  13. Microhardness of light- and dual-polymerizable luting resins polymerized through 7.5-mm-thick endocrowns.

    Science.gov (United States)

    Gregor, Ladislav; Bouillaguet, Serge; Onisor, Ioana; Ardu, Stefano; Krejci, Ivo; Rocca, Giovanni Tommaso

    2014-10-01

    The complete polymerization of luting resins through thick indirect restorations is still questioned. The purpose of this study was to evaluate the degree of polymerization of light- and dual-polymerizable luting resins under thick indirect composite resin and ceramic endocrowns by means of Vickers microhardness measurements. The Vickers microhardness measurements of a light-polymerizable microhybrid composite resin and a dual-polymerizable luting cement directly polymerized in a natural tooth mold for 40 seconds with a high-power light-emitting diode lamp (control) were compared with measurements after indirect irradiation through 7.5-mm-thick composite resin and ceramic endocrowns for 3 × 90 seconds. A test-to-control microhardness values ratio of 0.80 at a depth of 0.5 mm below the surface was assumed as the criterion for adequate conversion. For the Vickers microhardness measurements of a dual-polymerizable luting cement, no differences (P>.05) were found between Vickers microhardness control values and values reported after polymerization through composite resin and ceramic endocrowns. For The Vickers microhardness measurements (±SD) of a light-polymerizable microhybrid composite resin, control values were significantly (P.05). Under the conditions of this in vitro study, Vickers microhardness values of the dual-polymerizable resin cement and the light-polymerizable restorative composite resin irradiated for 3 × 90 seconds with a high irradiance light-emitting diode lamp through 7.5-mm-thick endocrowns reached at least 80% of the control Vickers microhardness values, which means that both materials can be adequately polymerized when they are used for luting thick indirect restorations. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  14. Manual for target thickness measurement by alpha particle irradiation

    International Nuclear Information System (INIS)

    Dias, J.F.; Martins, M.N.

    1990-04-01

    A system is described for thin-target thickness measurement through the alpha particle energy loss when them traverse the target. It is also described the program used in the analysis of the target thickness. (L.C.) [pt

  15. The Thickness Dependence of Optical Constants of Ultrathin Iron Films

    International Nuclear Information System (INIS)

    Gao Shang; Lian Jie; Wang Xiao; Li Ping; Sun Xiao-Fen; Li Qing-Hao

    2013-01-01

    Ultrathin iron films with different thicknesses from 7.1 to 51.7 nm are deposited by magnetron sputtering and covered by tantalum layers protecting them from being oxidized. These ultrathin iron films are studied by spectroscopic ellipsometry and transmittance measurement. An extra tantalum film is deposited under the same sputtering conditions and its optical constants and film thickness are obtained by a combination of ellipsometry and transmission measurement. After introducing these obtained optical constants and film thickness into the tantalum-iron film, the optical constants and film thicknesses of ultrathin iron films with different thicknesses are obtained. The results show that combining ellipsometry and transmission measurement improves the uniqueness of the obtained film thickness. The optical constants of ultrathin iron films depend strongly on film thicknesses. There is a broad absorption peak at about 370 nm and it shifts to 410 nm with film thickness decreasing

  16. Equilibrium helium film in the thick film limit

    International Nuclear Information System (INIS)

    Klier, J.; Schletterer, F.; Leiderer, P.; Shikin, V.

    2003-01-01

    For the thickness of a liquid or solid quantum film, like liquid helium or solid hydrogen, there exist still open questions about how the film thickness develops in certain limits. One of these is the thick film limit, i.e., the crossover from the thick film to bulk. We have performed measurements in this range using the surface plasmon resonance technique and an evaporated Ag film deposited on glass as substrate. The thickness of the adsorbed helium film is varied by changing the distance h of the bulk reservoir to the surface of the substrate. In the limiting case, when h > 0, the film thickness approaches about 100 nm following the van der Waals law in the retarded regime. The film thickness and its dependence on h is precisely determined and theoretically modeled. The equilibrium film thickness behaviour is discussed in detail. The agreement between theory and experiment is very good

  17. Factors influencing endometrial thickness in postmenopausal women.

    Science.gov (United States)

    Hebbar, S; Chaya, V; Rai, L; Ramachandran, A

    2014-07-01

    Cut-off values for endometrial thickness (ET) in asymptomatic postmenopausal woman have been standardized. However, there are no comprehensive studies to document how various factors can influence the ET after the age of menopause. To study the various factors influencing the ET in postmenopausal women. This was a prospective observational study. A total of 110 postmenopausal women underwent detailed history taking, clinical examination, and transvaginal scan for uterine volume and ovarian volume. The volumes were calculated by using ellipsoid formula: Width × thickness × height × 0.523. The variation in ET with respect to the influencing factors such as age, duration of menopause, parity, body mass index (BMI), medical illness like diabetes/hypertension, drugs like tamoxifen, presence of myoma, uterine volume, ovarian volume, and serum estradiol (in selected patients) were measured. Descriptive analysis was performed using SPSS software (version 16, Chicago II, USA) to obtain mean, standard deviation (SD), 95% confidence intervals (CIs) and inter quartile ranges. Comparison of means was carried out using analysis of variance. The mean (SD) age of the patients was 55.4 (6.91) years (95% CI, 54.1, 56.7). The mean (SD) age at menopause was 47.95 (3.90) years (95% CI, 47.2, 48.7) and the mean (SD) duration of menopause was 7.27 (6.65) years (95% CI, 6.01, 8.53). The mean (SD) ET was 3.8 (2.3) mm (95% CI, 3.36, 4.23). Medical illness like diabetes and hypertension did not alter the ET. ET increased as BMI increased and it was statistically significant. The presence of myoma increased uterine volume significantly and was associated with thick endometrial stripe. Similarly, whenever the ovaries were visualized and as the ovarian volume increased, there was an increase in ET. When ET was > 4 mm (n = 37), they were offered endocel, of which 16 agreed to undergo the procedure. None were found to have endometrial cancer. This study suggests that parity, BMI, presence of

  18. Dual-energy digital mammography: Calibration and inverse-mapping techniques to estimate calcification thickness and glandular-tissue ratio

    International Nuclear Information System (INIS)

    Kappadath, S. Cheenu; Shaw, Chris C.

    2003-01-01

    Breast cancer may manifest as microcalcifications in x-ray mammography. Small microcalcifications, essential to the early detection of breast cancer, are often obscured by overlapping tissue structures. Dual-energy imaging, where separate low- and high-energy images are acquired and synthesized to cancel the tissue structures, may improve the ability to detect and visualize microcalcifications. Transmission measurements at two different kVp values were made on breast-tissue-equivalent materials under narrow-beam geometry using an indirect flat-panel mammographic imager. The imaging scenario consisted of variable aluminum thickness (to simulate calcifications) and variable glandular ratio (defined as the ratio of the glandular-tissue thickness to the total tissue thickness) for a fixed total tissue thickness--the clinical situation of microcalcification imaging with varying tissue composition under breast compression. The coefficients of the inverse-mapping functions used to determine material composition from dual-energy measurements were calculated by a least-squares analysis. The linear function poorly modeled both the aluminum thickness and the glandular ratio. The inverse-mapping functions were found to vary as analytic functions of second (conic) or third (cubic) order. By comparing the model predictions with the calibration values, the root-mean-square residuals for both the cubic and the conic functions were ∼50 μm for the aluminum thickness and ∼0.05 for the glandular ratio

  19. The thickness of the interplanetary collisionless shock waves

    International Nuclear Information System (INIS)

    Pinter, S.

    1980-05-01

    The thicknesses of magnetic structures of the interplanetary shock waves related to the upstream solar wind plasma parameters are studied. From this study the following results have been obtained: the measured shock thickness increases for decreasing upstream proton number density and decreases for increasing proton flux energy. The shock thickness strongly depends on the ion plasma β, i.e. for higher values of the β the thickness decreases. (author)

  20. Measuring coating thicknesses on continuously moving material

    International Nuclear Information System (INIS)

    Holler, J.H.; Stanton, W.B.; Spongr, J.J.; Joffe, B.B.; Raffelsberger, P.W.; Tiebor, J.E.

    1982-01-01

    A method and apparatus using radiation techniques for measuring coating thicknesses on continuously moving strip material without altering a predetermined path along which it travels. A shuttle carrying a measuring probe having a radioactive isotope source and a detection device is provided for reciprocation along a preselected segment of the path of the strip. The shuttle and the probe are releasably engaged with the strip and carried thereby for synchronous movement therewith in the forward direction during a measurement cycle, and are disengaged from the strip when no measurement is being made, the movement of the shuttle then being controlled by an independent drive mechanism, shown as a belt drive, which reciprocates the shuttle along the rails. A belt drives it forward more slowly than the strip, which then engages the shuttle to pull it at strip speed, allowed by a pulley clutch. (author)

  1. Photoelastic Analysis of Cracked Thick Walled Cylinders

    Science.gov (United States)

    Pastramă, Ştefan Dan

    2017-12-01

    In this paper, the experimental determination of the stress intensity factor in thick walled cylinders subject to uniform internal pressure and having longitudinal non-penetrating cracks is presented. Photoelastic measurements were used together with the expressions of the stress field near the crack tip for Mode I crack extension and a specific methodology for stress intensity factor determination. Two types of longitudinal cracks - internal and external - were considered. Four plane models were manufactured and analyzed in a plane polariscope at different values of the applied internal pressure. The values of the normalized stress intensity factor were calculated and the results were compared to those reported by other authors. A good accuracy was noticed, showing the reliability of the experimental procedure.

  2. Critical currents of variable thickness bridges

    International Nuclear Information System (INIS)

    Lapir, G.M.; Likharev, K.K.; Maslova, L.A.; Semenov, V.K.

    1975-01-01

    A variable thickness bridge (VTB) is a short strip of thin normal or superconducting electrodes - 'banks'. This type of weak link has the peculiarity of having the changes of the modulus of the orderparameter localized in the film of the bridge. Only changes of the phase of the orderparameter take place in the banks, and so the electrodynamics of the banks is linear. The problem of the distribution of the linear density of current Jsub(s)(psi) and of the phase difference of the banks psi along the VTB width is considered and the critical current Isub(c) for the important case of a VTB deposited over a superconducting ground plate - 'screen' is calculated. (Auth.)

  3. Reduced cortical thickness in gambling disorder

    DEFF Research Database (Denmark)

    Grant, Jon E; Odlaug, Brian Lawrence; Chamberlain, Samuel R

    2015-01-01

    with significant reductions (average 15.8-19.9 %) in cortical thickness, versus controls, predominantly in right frontal cortical regions. Pronounced right frontal morphometric brain abnormalities occur in gambling disorder, supporting neurobiological overlap with substance disorders and its recent......Gambling disorder has recently been recognized as a prototype 'behavioral addiction' by virtue of its inclusion in the DSM-5 category of 'Substance-Related and Addictive Disorders.' Despite its newly acquired status and prevalence rate of 1-3 % globally, relatively little is known regarding...... the neurobiology of this disorder. The aim of this study was to explore cortical morphometry in untreated gambling disorder, for the first time. Subjects with gambling disorder (N = 16) free from current psychotropic medication or psychiatric comorbidities, and healthy controls (N = 17), were entered...

  4. On thick domain walls in general relativity

    Science.gov (United States)

    Goetz, Guenter; Noetzold, Dirk

    1989-01-01

    Planar scalar field configurations in general relativity differ considerably from those in flat space. It is shown that static domain walls of finite thickness in curved space-time do not possess a reflection symmetry. At infinity, the space-time tends to the Taub vacuum on one side of the wall and to the Minkowski vacuum (Rindler space-time) on the other. Massive test particles are always accelerated towards the Minkowski side, i.e., domain walls are attractive on the Taub side, but repulsive on the Minkowski side (Taub-vacuum cleaner). It is also proved that the pressure in all directions is always negative. Finally, a brief comment is made concerning the possibility of infinite, i.e., bigger than horizon size, domain walls in our universe. All of the results are independent of the form of the potential V(phi) greater than or equal to 0 of the scalar field phi.

  5. Thick-film analysis: literature search and bibliography

    International Nuclear Information System (INIS)

    Gehman, R.W.

    1981-09-01

    A literature search was conducted to support development of in-house diagnostic testing of thick film materials for hybrid microcircuits. A background literature review covered thick film formulation, processing, structure, and performance. Important material properties and tests were identified and several test procedures were obtained. Several tests were selected for thick film diagnosis at Bendix Kansas City. 126 references

  6. Thickness measuring instrument for rubber cord calender production

    International Nuclear Information System (INIS)

    Ye Songfeng

    1988-01-01

    The thickness measuring gauge has been used to measure the rubber film thickness on the coating of textile cord at tire four cord calenders. Combined with micro-computer it completes the automatic control system and acheives automatic thickness measurement and adjustment. The fundamentals, construction, specifications, characteristic and application results are described. Prominent economic benefit has been gained for tire production

  7. A note on thick subcategories of stable derived categories

    OpenAIRE

    Krause, Henning; Stevenson, Greg

    2013-01-01

    For an exact category having enough projective objects, we establish a bijection between thick subcategories containing the projective objects and thick subcategories of the stable derived category. Using this bijection, we classify thick subcategories of finitely generated modules over strict local complete intersections and produce generators for the category of coherent sheaves on a separated Noetherian scheme with an ample family of line bundles.

  8. The design and characteristics of QNT-type thickness gauge

    International Nuclear Information System (INIS)

    Li Furong; Liu Yisi

    1992-01-01

    The theoretical projection of QNT-Type radiation thickness gauge is given. The relations between sensitivity and radiation energy, the thickness resolution and the effect of scattering radiation have been discussed. The characteristics of this type of thickness gauge were described

  9. Composite gravity and composite supergravity

    International Nuclear Information System (INIS)

    Lukierski, J.

    1982-09-01

    It is known that the composite YM H-gauge theory can be constructed from σ-fields taking values in a symmetric Riemannian space G/H. We extend such a framework to graded σ-fields taking values in supercosets. We show that from supercoset σ-fields one can construct composite gravity, and from supercoset σ-superfields the composite supergravity models. (author)

  10. Formation and investigation of multilayer nanostructured coatings TiN/MoN for different layers thicknesses with c-pvd

    International Nuclear Information System (INIS)

    Pogrebnyak, A.D.; Bondar, O.V.; Postol'nyj, B.A.; Andreev, A.A.; Abadias, G.; Beresnev, V.M.; Sobol', O.B.

    2013-01-01

    Multilayer coatings based on TiN/MoN were obtained using the vacuum arc evaporation cathode method (C-PVD). Multilayers thickness was in the range 6,7 ÷ 8,7 μm and monolayers thickness was 2, 10, 20 and 40 nm. Vacuum-arc unit Bulat 6 was used for depositions. For the analysis of multilayer structures and properties of nanostructured coatings XRD analysis method was used (D8 ADVANCE, Bruker). For elemental composition and morphology investigation of the surface layers and multilayered coatings SEM (JEOL-7001F) with EDX attachment was used. Also HRTEM method was used to analyze the phase composition. In addition, this article provides investigation of hardness by Micro-Hardness Tester CSM (Switzerland). AFM was used for additional analysis of the topography and surface roughness of these coatings. This investigation have revealed the relationship between the layers thicknesses, substrate potential, the annealing process, physical and mechanical properties of samples. (authors)

  11. Variation of structure and magnetic properties with thickness of thin Co59Fe26Ni15 films

    NARCIS (Netherlands)

    Chechenin, NG; van Voorthuysen, EHD; De Hosson, JTM; Boerma, DO

    Variations of phase composition and magnetic properties of electrodeposited nanocrystalline Co-Fe-Ni films with film thickness in the range of 50-500 nm were analyzed. The samples were magnetically soft with coercivity in the range H-c = 2-20 Oe and uni axial magnetic anisotropy up to H-k = 20 Oe.

  12. Composite Territories

    DEFF Research Database (Denmark)

    Nicholas, Paul; Tamke, Martin

    2012-01-01

    and assembly of the fibre reinforced composite structure Composite Territories, in which the property of bending is activated and varied so as to match solely through material means a desired form. This case study demonstrates how one might extend the geometric model so that it is able to engage and reconcile...

  13. Materiaux composites supraconducteurs

    Science.gov (United States)

    Kerjouan, Philippe; Boterel, Florence; Lostec, Jean; Bertot, Jean-Paul; Haussonne, Jean-Marie

    1991-11-01

    The new superconductor materials with a high critical current own a large importance as well in the electronic components or in the electrotechnical devices fields. The deposit of such materials with the thick films technology is to be more and more developped in the years to come. Therefore, we tried to realize such thick films screen printed on alumina, and composed mainly of the YBa2CU3O{7-δ} material. We first realized a composite material glass/YBa2CU3O{7-δ}, by analogy with the classical screen-printed inks where the glass ensures the bonding with the substrate. We thus realized different materials by using some different classes of glass. These materials owned a superconducting transition close to the one of the pure YBa2CU3O{7-δ} material. We made a slurry with the most significant composite materials and binders, and screen-printed them on an alumina substrate preliminary or not coated with a diffusion barrier layer. After firing, we studied the thick films adhesion, the alumina/glass/composite material interfaces, and their superconducting properties. Les nouveaux matériaux supraconducteurs à haute température critique ont potentiellement un rôle important à jouer dans le domaine de l'électronique et de l'électrotechnique. En particulier, le dépôt d'oxydes supraconducteurs sur divers types de substrats est une technologie amenée à se développer. Nous avons donc entrepris une étude dont l'objet est la réalisation de conducteurs sérigraphiés sur alumine et composés essentiellement du matériau YBa2CU3O{7-δ}. Nous avons tout d'abord cherché à réaliser un composite verre/YBa2CU3O{7-δ}, par analogie au principe de réalisation de couches conductrices sérigraphiées, le verre permettant d'obtenir une liaison physico-chimique avec le substrat. Une étude préliminaire a permis de réaliser divers matériaux composites massifs, utilisant différentes familles de verres. Ces matériaux massifs, se présentant sous la forme de barreaux de

  14. Neutronic performance of decoupled poisoned and unpoisoned composite moderators for high resolution experiments

    International Nuclear Information System (INIS)

    Kai, Tetsuya; Harada, Masahide; Watanabe, Noboru; Teshigawara, Makoto; Sakata, Hideaki; Ikeda, Yujiro

    2001-01-01

    We studied decoupled poisoned and un-poisoned composite moderators consisting of 20 mm thick hydrogen and 30 mm thick light water. The neutron pulses from un-poisoned one were much broader with longer decay times than a simple decoupled hydrogen moderator in 50 mm thickness. It was also found that the poisoned composite moderator provides higher pulse peak intensities relative to the hydrogen moderator (poisoned at 20 mm) below several tens meV with no penalty of pulse width. (author)

  15. Critical current density and microstructure of YBa2Cu3O7-x films as a function of film thickness

    International Nuclear Information System (INIS)

    Mogro-Campero, A.; Turner, L.G.; Hall, E.L.; Lewis, N.

    1990-01-01

    Thin films of nominal composition YBa 2 Cu 3 O 7-x (YBCO) were produced on (100) SrTiO 3 substrates by coevaporation and furnace annealing. Film thicknesses in the range of 0.2 to 2.4 μm were analyzed. Microstructural investigations by cross sectional transmission electron microscopy (TEM) reveal a continuous layer of about 0.4 μm thickness adjacent to the substrate with c-axis normal to the substrate plane. In thicker films the remaining top portion has the c-axis in the film plane. The critical current density (J c ) at 77 K decreases with increasing thickness in the thickness range exceeding 0.4 μm, qualitatively consistent with the microstructural observation, but quantitatively inconsistent with a simple model based on the microstructural data

  16. In situ measurement using FBGs of process-induced strains during curing of thick glass/epoxy laminate plate

    DEFF Research Database (Denmark)

    Nielsen, Michael Wenani; Schmidt, Jacob Wittrup; Hattel, Jesper Henri

    2012-01-01

    For large composite structures, such as wind turbine blades, thick laminates are required to withstand large in-service loads. During the manufacture of thick laminates, one of the challenges met is avoiding process-induced shape distortions and residual stresses. In this paper, embedded fibre...... Bragg grating sensors are used to monitor process-induced strains during vacuum infusion of a thick glass/epoxy laminate. The measured strains are compared with predictions from a cure hardening instantaneous linear elastic (CHILE) thermomechanical numerical model where different mechanical boundary...... conditions are employed. The accuracy of the CHILE model in predicting process-induced internal strains, in what is essentially a viscoelastic boundary value problem, is investigated. A parametric study is furthermore performed to reveal the effect of increasing the laminate thickness. The numerical model...

  17. Of mice, men and elephants: the relation between articular cartilage thickness and body mass.

    Directory of Open Access Journals (Sweden)

    Jos Malda

    Full Text Available Mammalian articular cartilage serves diverse functions, including shock absorption, force transmission and enabling low-friction joint motion. These challenging requirements are met by the tissue's thickness combined with its highly specific extracellular matrix, consisting of a glycosaminoglycan-interspersed collagen fiber network that provides a unique combination of resilience and high compressive and shear resistance. It is unknown how this critical tissue deals with the challenges posed by increases in body mass. For this study, osteochondral cores were harvested post-mortem from the central sites of both medial and lateral femoral condyles of 58 different mammalian species ranging from 25 g (mouse to 4000 kg (African elephant. Joint size and cartilage thickness were measured and biochemical composition (glycosaminoclycan, collagen and DNA content and collagen cross-links densities were analyzed. Here, we show that cartilage thickness at the femoral condyle in the mammalian species investigated varies between 90 µm and 3000 µm and bears a negative allometric relationship to body mass, unlike the isometric scaling of the skeleton. Cellular density (as determined by DNA content decreases with increasing body mass, but gross biochemical composition is remarkably constant. This however need not affect life-long performance of the tissue in heavier mammals, due to relatively constant static compressive stresses, the zonal organization of the tissue and additional compensation by joint congruence, posture and activity pattern of larger mammals. These findings provide insight in the scaling of articular cartilage thickness with body weight, as well as in cartilage biochemical composition and cellularity across mammalian species. They underscore the need for the use of appropriate in vivo models in translational research aiming at human applications.

  18. Of Mice, Men and Elephants: The Relation between Articular Cartilage Thickness and Body Mass

    Science.gov (United States)

    Malda, Jos; de Grauw, Janny C.; Benders, Kim E. M.; Kik, Marja J. L.; van de Lest, Chris H. A.; Creemers, Laura B.; Dhert, Wouter J. A.; van Weeren, P. René

    2013-01-01

    Mammalian articular cartilage serves diverse functions, including shock absorption, force transmission and enabling low-friction joint motion. These challenging requirements are met by the tissue’s thickness combined with its highly specific extracellular matrix, consisting of a glycosaminoglycan-interspersed collagen fiber network that provides a unique combination of resilience and high compressive and shear resistance. It is unknown how this critical tissue deals with the challenges posed by increases in body mass. For this study, osteochondral cores were harvested post-mortem from the central sites of both medial and lateral femoral condyles of 58 different mammalian species ranging from 25 g (mouse) to 4000 kg (African elephant). Joint size and cartilage thickness were measured and biochemical composition (glycosaminoclycan, collagen and DNA content) and collagen cross-links densities were analyzed. Here, we show that cartilage thickness at the femoral condyle in the mammalian species investigated varies between 90 µm and 3000 µm and bears a negative allometric relationship to body mass, unlike the isometric scaling of the skeleton. Cellular density (as determined by DNA content) decreases with increasing body mass, but gross biochemical composition is remarkably constant. This however need not affect life-long performance of the tissue in heavier mammals, due to relatively constant static compressive stresses, the zonal organization of the tissue and additional compensation by joint congruence, posture and activity pattern of larger mammals. These findings provide insight in the scaling of articular cartilage thickness with body weight, as well as in cartilage biochemical composition and cellularity across mammalian species. They underscore the need for the use of appropriate in vivo models in translational research aiming at human applications. PMID:23437402

  19. Pyrotechnic Smoke Compositions Containing Boron Carbide

    Science.gov (United States)

    2012-06-10

    smoke. Experimentation and thermodynamic modeling were used in conjunction to develop the compositions which were then evaluated both visually and by...fuel to produce thick clouds of white smoke. Experimentation and thermodynamic modeling were used in conjunction to develop the compositions which...Transmittance-based measurements may be used to quantify the effectiveness of screening smokes. The Beer -Lambert law is used to define the figures of merit

  20. Influence of slice thickness on the determination of left ventricular wall thickness and dimension by magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ohnishi, Shusaku; Fukui, Sugao; Atsumi, Chisato and others

    1989-02-01

    Wall thickness of the ventricular septum and left ventricle, and left ventricular cavity dimension were determined on magnetic resonance (MR) images with slices 5 mm and 10 mm in thickness. Subjects were 3 healthy volunteers and 7 patients with hypertension (4), hypertrophic cardiomyopathy (one) or valvular heart disease (2). In visualizing the cardiac structures such as left ventricular papillary muscle and right and left ventricles, 5 mm-thick images were better than 10 mm-thick images. Edges of ventricular septum and left ventricular wall were more clearly visualized on 5 mm-thick images than 10 mm-thick images. Two mm-thick MR images obtained from 2 patients yielded the most excellent visualization in end-systole, but failed to reveal cardiac structures in detail in end-diastole. Phantom studies revealed no significant differences in image quality of 10 mm and 5 mm in thickness in the axial view 80 degree to the long axis. In the axial view 45 degree to the long axis, 10 mm-thick images were inferior to 5 mm-thick images in detecting the edge of the septum and the left ventricular wall. These results indicate that the selection of slice thickness is one of the most important determinant factors in the measurement of left ventricular wall thickness and cavity dimension. (Namekawa, K).