WorldWideScience

Sample records for material core types

  1. An in vitro comparative evaluation of physical properties of four different types of core materials

    OpenAIRE

    2014-01-01

    Introduction: Compressive and tensile stresses of core materials are important properties because cores usually replace a large bulk of tooth structure and must resist multidirectional masticatory forces for many years. Material and Methods: The present study was undertaken to find out the best core build up material with respect to their physical properties among resin-based composites. Individual compressive, tensile, and flexural strength of fiber-reinforced dual cure resin core build...

  2. An in vitro comparative evaluation of physical properties of four different types of core materials

    Directory of Open Access Journals (Sweden)

    Antara Agrawal

    2014-01-01

    Full Text Available Introduction: Compressive and tensile stresses of core materials are important properties because cores usually replace a large bulk of tooth structure and must resist multidirectional masticatory forces for many years. Material and Methods: The present study was undertaken to find out the best core build up material with respect to their physical properties among resin-based composites. Individual compressive, tensile, and flexural strength of fiber-reinforced dual cure resin core build up material, silorane-based composite resin, and dual curing composite for core build up with silver amalgam core was used as control were evaluated and compared using universal testing machine. Data were statistical analysed using Kruskal-Wallis test to determine whether statistically significant differences (P < 0.05 existed among core materials. Both dual cure composite materials with nanofillers were found superior to amalgam core. The silorane-based material showed the highest flexural strength, but other mechanical properties were inferior to dual cure composite materials with nanofillers.

  3. Survival of extensively damaged endodontically treated incisors restored with different types of posts-and-core foundation restoration material.

    Science.gov (United States)

    Lazari, Priscilla Cardoso; de Carvalho, Marco Aurélio; Del Bel Cury, Altair A; Magne, Pascal

    2017-09-16

    Which post-and-core combination will best improve the performance of extensively damaged endodontically treated incisors without a ferrule is still unclear. The purpose of this in vitro study was to investigate the restoration of extensively damaged endodontically treated incisors without a ferrule using glass-ceramic crowns bonded to various composite resin foundation restorations and 2 types of posts. Sixty decoronated endodontically treated bovine incisors without a ferrule were divided into 4 groups and restored with various post-and-core foundation restorations. NfPfB=no-ferrule (Nf) with glass-fiber post (Pf) and bulk-fill resin foundation restoration (B); NfPfP=no-ferrule (Nf) with glass-fiber post (Pf) and dual-polymerized composite resin core foundation restoration (P); NfPt=no-ferrule (Nf) with titanium post (Pt) and resin core foundation restoration; and NfPtB=no-ferrule (Nf) with titanium post (Pt) and bulk-fill resin core foundation restoration (B). Two additional groups from previously published data from the same authors (FPf=2mm of ferrule (F) and glass-fiber post (Pf) and composite resin core foundation restoration; and NfPf=no-ferrule (Nf) with glass-fiber post (Pf) and composite resin core foundation restoration), which were tested concomitantly and using the same experimental arrangement, were included for comparison. All teeth were prepared to receive bonded glass-ceramic crowns luted with dual-polymerized resin cement and were subjected to accelerated fatigue testing under submerged conditions at room temperature. Cyclic isometric loading was applied to the incisal edge at an angle of 30 degrees with a frequency of 5 Hz, beginning with a load of 100 N (5000 cycles). A 100-N load increase was applied every 15000 cycles. The specimens were loaded until failure or to a maximum of 1000 N (140000 cycles). The 6 groups (4 groups from the present study and 2 groups from the previously published study) were compared using the Kaplan-Meier survival

  4. Stability of Molten Core Materials

    Energy Technology Data Exchange (ETDEWEB)

    Layne Pincock; Wendell Hintze

    2013-01-01

    The purpose of this report is to document a literature and data search for data and information pertaining to the stability of nuclear reactor molten core materials. This includes data and analysis from TMI-2 fuel and INL’s LOFT (Loss of Fluid Test) reactor project and other sources.

  5. Metal-Organic Framework Derived Iron Sulfide-Carbon Core-Shell Nanorods as a Conversion-Type Battery Material

    DEFF Research Database (Denmark)

    Huang, Wei; Li, Shuo; Cao, Xianyi

    2017-01-01

    to prepare carbon-encapsulated ploy iron sulfide through solid-state chemical sulfurizing. The resulting core-shell nanorods consisting of approximately 13% carbon and 87% Fe7S8 have a hierarchically porous structure and a very high specific surface area of 277 m2g-1. When tested for use in fabrication...... of systematic structural analysis and microscopic mapping, we discuss the charge-discharge mechanisms and the crucial factors associated with the stability and structural changes upon charge-discharge cycling....

  6. Material with core-shell structure

    Science.gov (United States)

    Luhrs, Claudia; Richard, Monique N.; Dehne, Aaron; Phillips, Jonathan; Stamm, Kimber L.; Fanson, Paul T.

    2011-11-15

    Disclosed is a material having a composite particle, the composite particle including an outer shell and a core. The core is made from a lithium alloying material and the outer shell has an inner volume that is greater in size than the core of the lithium alloying material. In some instances, the outer mean diameter of the outer shell is less than 500 nanometers and the core occupies between 5 and 99% of the inner volume. In addition, the outer shell can have an average wall thickness of less than 100 nanometers.

  7. Standard Guide for Identification of Fibers, Fillers, and Core Materials in Computerized Material Property Databases

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1992-01-01

    1.1 This guide establishes the essential and desirable elements of data required for the identification in computerized material property databases of fibers, fillers, and core materials used in composite materials. A recommended format for entry of these fields into a computerized database is provided. Examples of the application of this guide are also included. 1.2 The recommended format described in this guide is suggested for use in recording data in a database, which is different from contractural reporting of actual test results. The latter type of information is described in materials specifications shown in business transactions and is subject to agreement between vendor and purchaser. 1.3 The materials covered by this guide include fibers, both continuous and discontinuous, and fillers of various geometries which are used as reinforcements in composite materials, as well as core materials used in sandwich composites. Cores may be foam, honeycomb, or naturally occurring materials such as balsa wood....

  8. Sodium fast reactor evaluation: Core materials

    Science.gov (United States)

    Cheon, Jin Sik; Lee, Chan Bock; Lee, Byoung Oon; Raison, J. P.; Mizuno, T.; Delage, F.; Carmack, J.

    2009-07-01

    In the framework of the Generation IV Sodium Fast Reactor (SFR) Program the Advanced Fuel Project has conducted an evaluation of the available fuel systems supporting future sodium cooled fast reactors. In this paper the status of available and developmental materials for SFR core cladding and duct applications is reviewed. To satisfy the Generation IV SFR fuel requirements, an advanced cladding needs to be developed. The candidate cladding materials are austenitic steels, ferritic/martensitic (F/M) steels, and oxide dispersion strengthened (ODS) steels. A large amount of irradiation testing is required, and the compatibility of cladding with TRU-loaded fuel at high temperatures and high burnup must be investigated. The more promising F/M steels (compared to HT9) might be able to meet the dose requirements of over 200 dpa for ducts in the GEN-IV SFR systems.

  9. The reprocessing of reactor core materials

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jing, E-mail: wang-jing@nuaa.edu.cn [State Key Laboratory of Mechanics and Control of Mechanial Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Liu, Bing; Shao, Youlin; Lu, Zhenming; Liu, Malin [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China)

    2014-05-01

    Generation IV high temperature gas-cooled reactors (HTGR) are preferentially fueled by spherical fuel elements, which are composed of a fuel zone of triso-coated uranium oxide (UO{sub 2}) particles and a matrix graphite layer. Unqualified coated particles and spherical fuel elements unavoidablely occur during the processing of coating UO{sub 2} kernels and embedding the coated particles into the graphite matrix. So it is necessary to reprocess the UO{sub 2} in the unqualified coated particles and spherical fuel elements to maximize the use of the reactor core materials. In this work, we present several methods to: (1) separate the coated particles from the graphite matrix and, (2) expose and recover the UO{sub 2} kernels from the coated particles. The comparison of different methods shows that the thermal oxidation of graphite by a fixed bed burner and the jet grinding of the unqualified coated particles are prosing in practice for the separation of coated particles from the graphite matrix and recovering the uranium dioxide kernels, respectively. Some other methods, such as etching the SiC layer with the active fluorine species in plasma generated by the dielectric barrier discharge (DBD) under the atmosphere also show their great potential values in the reprocessing of reactor core materials, especially for the activated and contaminated fuels.

  10. Development of core sampling technique for ITER Type B radwaste

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. G.; Hong, K. P.; Oh, W. H.; Park, M. C.; Jung, S. H.; Ahn, S. B. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Type B radwaste (intermediate level and long lived radioactive waste) imported from ITER vacuum vessel are to be treated and stored in basement of hot cell building. The Type B radwaste treatment process is composed of buffer storage, cutting, sampling/tritium measurement, tritium removal, characterization, pre-packaging, inspection/decontamination, and storage etc. The cut slices of Type B radwaste components generated from cutting process undergo sampling process before and after tritium removal process. The purpose of sampling is to obtain small pieces of samples in order to investigate the tritium content and concentration of Type B radwaste. Core sampling, which is the candidates of sampling technique to be applied to ITER hot cell, is available for not thick (less than 50 mm) metal without use of coolant. Experimented materials were SS316L and CuCrZr in order to simulate ITER Type B radwaste. In core sampling, substantial secondary wastes from cutting chips will be produced unavoidably. Thus, core sampling machine will have to be equipped with disposal system such as suction equipment. Core sampling is considered an unfavorable method for tool wear compared to conventional drilling.

  11. Microparticles obtained by complex coacervation: influence of the type of reticulation and the drying process on the release of the core material

    Directory of Open Access Journals (Sweden)

    Izabela Dutra Alvim

    2010-12-01

    Full Text Available Microparticles obtained by complex coacervation were crosslinked with glutaraldehyde or with transglutaminase and dried using freeze drying or spray drying. Moist samples presented Encapsulation Efficiency (%EE higher than 96%. The mean diameters ranged from 43.7 ± 3.4 to 96.4 ± 10.3 µm for moist samples, from 38.1 ± 5.36 to 65.2 ± 16.1 µm for dried samples, and from 62.5 ± 7.5 to 106.9 ± 26.1 µm for rehydrated microparticles. The integrity of the particles without crosslinking was maintained when freeze drying was used. After spray drying, only crosslinked samples were able to maintain the wall integrity. Microparticles had a round shape and in the case of dried samples rugged walls apparently without cracks were observed. Core distribution inside the particles was multinuclear and homogeneous and core release was evaluated using anhydrous ethanol. Moist particles crosslinked with glutaraldehyde at the concentration of 1.0 mM.g-1 protein (ptn, were more efficient with respect to the core retention compared to 0.1 mM.g-1 ptn or those crosslinked with transglutaminase (10 U.g-1 ptn. The drying processes had a strong influence on the core release profile reducing the amount released to all dry samples

  12. Scaling of Core Material in Rubble Mound Breakwater Model Tests

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Z.; Troch, P.

    1999-01-01

    The permeability of the core material influences armour stability, wave run-up and wave overtopping. The main problem related to the scaling of core materials in models is that the hydraulic gradient and the pore velocity are varying in space and time. This makes it impossible to arrive at a fully...... correct scaling. The paper presents an empirical formula for the estimation of the wave induced pressure gradient in the core, based on measurements in models and a prototype. The formula, together with the Forchheimer equation can be used for the estimation of pore velocities in cores. The paper proposes...... that the diameter of the core material in models is chosen in such a way that the Froude scale law holds for a characteristic pore velocity. The characteristic pore velocity is chosen as the average velocity of a most critical area in the core with respect to porous flow. Finally the method is demonstrated...

  13. Advanced Materials and Solids Analysis Research Core (AMSARC)

    Science.gov (United States)

    The Advanced Materials and Solids Analysis Research Core (AMSARC), centered at the U.S. Environmental Protection Agency's (EPA) Andrew W. Breidenbach Environmental Research Center in Cincinnati, Ohio, is the foundation for the Agency's solids and surfaces analysis capabilities. ...

  14. Advanced Materials and Solids Analysis Research Core (AMSARC)

    Science.gov (United States)

    The Advanced Materials and Solids Analysis Research Core (AMSARC), centered at the U.S. Environmental Protection Agency's (EPA) Andrew W. Breidenbach Environmental Research Center in Cincinnati, Ohio, is the foundation for the Agency's solids and surfaces analysis capabilities. ...

  15. Innovative core material produced by infusion process using hemp fibres

    Science.gov (United States)

    Boccarusso, L.; Carrino, L.; Durante, M.; Formisano, A.; Langella, A.; Minutolo, F. Memola Capece

    2016-10-01

    This paper investigates the mechanical properties in term of compression, tensile, flexural and shear strength of a new hemp core based on woven fabric. The hemp core is manufactured by means an innovative vacuum infusion process in which the input both of epoxy resin and of air was allowed. In addition, a comparison among this and others more known materials used as core in sandwich structures was carried out. The results showed that the core under investigation has higher mechanical properties, without shear and indentation failure during the tests on the respective sandwich structures.

  16. A finite element thermal analysis of various dowel and core materials

    Directory of Open Access Journals (Sweden)

    Shanti Varghese

    2012-01-01

    Conclusion: Non-metallic dowel and core materials such as fibre reinforced composite dowels (FRC generate greater stress than metallic dowel and core materials. This emphasized the preferable use of the metallic dowel and core materials in the oral environment.

  17. Typing a Core Binary Field Arithmetic in a Light Logic

    OpenAIRE

    Cesena, Emanuele; Pedicini, Marco; Roversi, Luca

    2011-01-01

    We design a library for binary field arithmetic and we supply a core API which is completely developed in DLAL, extended with a fix point formula. Since DLAL is a restriction of linear logic where only functional programs with polynomial evaluation cost can be typed, we obtain the core of a functional programming setting for binary field arithmetic with built-in polynomial complexity.

  18. Spectrophotometric Evaluation of Polyetheretherketone (PEEK as a Core Material and a Comparison with Gold Standard Core Materials

    Directory of Open Access Journals (Sweden)

    Bogna Stawarczyk

    2016-06-01

    Full Text Available This study investigated the colorimetric properties of different veneering materials on core materials. Standardized specimens (10 mm × 10 mm × 1.5 mm reflecting four core (polyetheretherketone (PEEK, zirconia (ZrO2, cobalt–chromium–molybdenum alloy (CoCrMo, and titanium oxide (TiO2; thickness: 1.5 mm and veneering materials (VITA Mark II, IPS e.max CAD, LAVA Ultimate and VITA Enamic, all in shade A3; thickness: 0.5, 1.0, 1.5 and 2 mm, respectively were fabricated. Specimens were superimposed to assemblies, and the color was determined with a spectrophotometer (CieLab-System or a chair-side color measurement device (VITA EasyShade, respectively. Data were analyzed using three-, two-, and one-way ANOVA, a Chi2-test, and a Wilson approach (p < 0.05. The measurements with EasyShade showed A2 for VITA Mark II, A3.5 for VITA Enamic, B2 for LAVA Ultimate, and B3 for IPS e.max CAD. LabE-values showed significant differences between the tested veneering materials (p < 0.001. CieLab-System and VITA EasyShade parameters of the different assemblies showed a significant impact of core (p < 0.001, veneering material (p < 0.001, and thickness of the veneering material (p < 0.001. PEEK as core material showed comparable outcomes as compared to ZrO2 and CoCrMo, with respect to CieLab-System parameters for each veneering material. The relative frequency of the measured VITA EasyShade parameters regarding PEEK cores also showed comparable results as compared to the gold standard CoCrMo, regardless of the veneering material used.

  19. Spectrophotometric Evaluation of Polyetheretherketone (PEEK) as a Core Material and a Comparison with Gold Standard Core Materials.

    Science.gov (United States)

    Stawarczyk, Bogna; Schmid, Philipp; Roos, Malgorzata; Eichberger, Marlis; Schmidlin, Patrick R

    2016-06-20

    This study investigated the colorimetric properties of different veneering materials on core materials. Standardized specimens (10 mm × 10 mm × 1.5 mm) reflecting four core (polyetheretherketone (PEEK), zirconia (ZrO₂), cobalt-chromium-molybdenum alloy (CoCrMo), and titanium oxide (TiO₂); thickness: 1.5 mm) and veneering materials (VITA Mark II, IPS e.max CAD, LAVA Ultimate and VITA Enamic, all in shade A3; thickness: 0.5, 1.0, 1.5 and 2 mm, respectively) were fabricated. Specimens were superimposed to assemblies, and the color was determined with a spectrophotometer (CieLab-System) or a chair-side color measurement device (VITA EasyShade), respectively. Data were analyzed using three-, two-, and one-way ANOVA, a Chi²-test, and a Wilson approach (p materials (p material (p material (p material showed comparable outcomes as compared to ZrO₂ and CoCrMo, with respect to CieLab-System parameters for each veneering material. The relative frequency of the measured VITA EasyShade parameters regarding PEEK cores also showed comparable results as compared to the gold standard CoCrMo, regardless of the veneering material used.

  20. Genomic variation in Salmonella enterica core genes for epidemiological typing

    Directory of Open Access Journals (Sweden)

    Leekitcharoenphon Pimlapas

    2012-03-01

    Full Text Available Abstract Background Technological advances in high throughput genome sequencing are making whole genome sequencing (WGS available as a routine tool for bacterial typing. Standardized procedures for identification of relevant genes and of variation are needed to enable comparison between studies and over time. The core genes--the genes that are conserved in all (or most members of a genus or species--are potentially good candidates for investigating genomic variation in phylogeny and epidemiology. Results We identify a set of 2,882 core genes clusters based on 73 publicly available Salmonella enterica genomes and evaluate their value as typing targets, comparing whole genome typing and traditional methods such as 16S and MLST. A consensus tree based on variation of core genes gives much better resolution than 16S and MLST; the pan-genome family tree is similar to the consensus tree, but with higher confidence. The core genes can be divided into two categories: a few highly variable genes and a larger set of conserved core genes, with low variance. For the most variable core genes, the variance in amino acid sequences is higher than for the corresponding nucleotide sequences, suggesting that there is a positive selection towards mutations leading to amino acid changes. Conclusions Genomic variation within the core genome is useful for investigating molecular evolution and providing candidate genes for bacterial genome typing. Identification of genes with different degrees of variation is important especially in trend analysis.

  1. Nanostructured core-shell electrode materials for electrochemical capacitors

    Science.gov (United States)

    Jiang, Long-bo; Yuan, Xing-zhong; Liang, Jie; Zhang, Jin; Wang, Hou; Zeng, Guang-ming

    2016-11-01

    Core-shell nanostructure represents a unique system for applications in electrochemical energy storage devices. Owing to the unique characteristics featuring high power delivery and long-term cycling stability, electrochemical capacitors (ECs) have emerged as one of the most attractive electrochemical storage systems since they can complement or even replace batteries in the energy storage field, especially when high power delivery or uptake is needed. This review aims to summarize recent progress on core-shell nanostructures for advanced supercapacitor applications in view of their hierarchical architecture which not only create the desired hierarchical porous channels, but also possess higher electrical conductivity and better structural mechanical stability. The core-shell nanostructures include carbon/carbon, carbon/metal oxide, carbon/conducting polymer, metal oxide/metal oxide, metal oxide/conducting polymer, conducting polymer/conducting polymer, and even more complex ternary core-shell nanoparticles. The preparation strategies, electrochemical performances, and structural stabilities of core-shell materials for ECs are summarized. The relationship between core-shell nanostructure and electrochemical performance is discussed in detail. In addition, the challenges and new trends in core-shell nanomaterials development have also been proposed.

  2. Core IV Materials for Metropolitan Agriculture/Horticulture Programs.

    Science.gov (United States)

    Hemp, Paul; And Others

    This core curriculum guide consists of materials for use in presenting a 13-unit vocational agriculture course geared toward high school students living in metropolitan areas. Addressed in the individual units of the course are the following topics: employment in agricultural occupations, supervised occupational experience, leadership in…

  3. Radiation quality factor of spherical antennas with material cores

    DEFF Research Database (Denmark)

    Hansen, Troels Vejle; Kim, Oleksiy S.; Breinbjerg, Olav

    2011-01-01

    This paper gives a description of the radiation quality factor and resonances of spherical antennas with material cores. Conditions for cavity and radiating resonances are given, and a theoretical description of the radiation quality factor, as well as simple expressions describing the relative...

  4. Repair bond strength of dual-cured resin composite core buildup materials.

    Science.gov (United States)

    El-Deeb, Heba A; Ghalab, Radwa M; Elsayed Akah, Mai M; Mobarak, Enas H

    2016-03-01

    The reparability of dual-cured resin composite core buildup materials using a light-cured one following one week or three months storage, prior to repair was evaluated. Two different dual-cured resin composites; Cosmecore™ DC automix and Clearfil™ DC automix core buildup materials and a light-cured nanofilled resin composite; Filtek™ Z350 XT were used. Substrate specimens were prepared (n = 12/each substrate material) and stored in artificial saliva at 37 °C either for one week or three months. Afterward, all specimens were ground flat, etched using Scotchbond™ phosphoric acid etchant and received Single Bond Universal adhesive system according to the manufacturers' instructions. The light-cured nanofilled resin composite (Filtek™ Z350 XT) was used as a repair material buildup. To determine the cohesive strength of each solid substrate material, additional specimens from each core material (n = 12) were prepared and stored for the same periods. Five sticks (0.8 ± 0.01 mm(2)) were obtained from each specimen (30 sticks/group) for microtensile bond strength (μTBS) testing. Modes of failure were also determined. Two-way ANOVA revealed a significant effect for the core materials but not for the storage periods or their interaction. After one week, dual-cured resin composite core buildup materials (Cosmecore™ DC and Clearfil™ DC) achieved significantly higher repair μTBS than the light-cured nanofilled resin composite (Filtek™ Z350 XT). However, Clearfil™ DC revealed the highest value, then Cosmecore™ DC and Filtek™ Z350 XT, following storage for 3-month. Repair strength values recovered 64-86% of the cohesive strengths of solid substrate materials. The predominant mode of failure was the mixed type. Dual-cured resin composite core buildup materials revealed acceptable repair bond strength values even after 3-month storage.

  5. The recent advances on carrier materials for microencapsulating lipophilic cores

    Directory of Open Access Journals (Sweden)

    JIN Minfeng

    2014-12-01

    Full Text Available Lipophilic ingredients,such as polyunsaturated fatty acids,play an important role in industrialized foods to fortify the nutrients.However,these materials are normally sensitive to oxygen,light or heat to be oxidized,and hard to flow and mix within the bulk food due to the hydrophobic nature.Microencapsulation of lipophilic materials could effectively extend their shelf lives,mask unsatisfied flavors,change their physicochemical properties,and enhance the mixing capacities.This work reviewed the different carrier materials applied in microencapsulating the lipophilic ingredients,and discussed their characteristics and effects on encapsulation efficiencies and release profiles of lipophilic cores.

  6. Electrical properties of spherical dipole antennas with lossy material cores

    DEFF Research Database (Denmark)

    Hansen, Troels Vejle; Kim, Oleksiy S.; Breinbjerg, Olav

    2012-01-01

    A spherical magnetic dipole antenna with a linear, isotropic, homogenous, passive, and lossy material core is modeled analytically, and closed form expressions are given for the internally stored magnetic and electric energies, the radiation efficiency, and radiation quality factor. This model...... size and permittivity, focusing on the effects of magnetic core losses for a simple magnetic dispersion model, to illustrate how stored energies, efficiency and quality factor are affected. This shows that large magnetic losses can be beneficial, as these can produce a relatively high efficiency....

  7. Tunable Band Gap and Conductivity Type of ZnSe/Si Core-Shell Nanowire Heterostructures

    Directory of Open Access Journals (Sweden)

    Yijie Zeng

    2014-10-01

    Full Text Available The electronic properties of zincblende ZnSe/Si core-shell nanowires (NWs with a diameter of 1.1–2.8 nm are calculated by means of the first principle calculation. Band gaps of both ZnSe-core/Si-shell and Si-core/ZnSe-shell NWs are much smaller than those of pure ZnSe or Si NWs. Band alignment analysis reveals that the small band gaps of ZnSe/Si core-shell NWs are caused by the interface state. Fixing the ZnSe core size and enlarging the Si shell would turn the NWs from intrinsic to p-type, then to metallic. However, Fixing the Si core and enlarging the ZnSe shell would not change the band gap significantly. The partial charge distribution diagram shows that the conduction band maximum (CBM is confined in Si, while the valence band maximum (VBM is mainly distributed around the interface. Our findings also show that the band gap and conductivity type of ZnSe/Si core-shell NWs can be tuned by the concentration and diameter of the core-shell material, respectively.

  8. Tunable Band Gap and Conductivity Type of ZnSe/Si Core-Shell Nanowire Heterostructures.

    Science.gov (United States)

    Zeng, Yijie; Xing, Huaizhong; Fang, Yanbian; Huang, Yan; Lu, Aijiang; Chen, Xiaoshuang

    2014-10-31

    The electronic properties of zincblende ZnSe/Si core-shell nanowires (NWs) with a diameter of 1.1-2.8 nm are calculated by means of the first principle calculation. Band gaps of both ZnSe-core/Si-shell and Si-core/ZnSe-shell NWs are much smaller than those of pure ZnSe or Si NWs. Band alignment analysis reveals that the small band gaps of ZnSe/Si core-shell NWs are caused by the interface state. Fixing the ZnSe core size and enlarging the Si shell would turn the NWs from intrinsic to p-type, then to metallic. However, Fixing the Si core and enlarging the ZnSe shell would not change the band gap significantly. The partial charge distribution diagram shows that the conduction band maximum (CBM) is confined in Si, while the valence band maximum (VBM) is mainly distributed around the interface. Our findings also show that the band gap and conductivity type of ZnSe/Si core-shell NWs can be tuned by the concentration and diameter of the core-shell material, respectively.

  9. Genomic variation in Salmonella enterica core genes for epidemiological typing

    DEFF Research Database (Denmark)

    Leekitcharoenphon, Pimlapas; Lukjancenko, Oksana; Rundsten, Carsten Friis

    2012-01-01

    Background: Technological advances in high throughput genome sequencing are making whole genome sequencing (WGS) available as a routine tool for bacterial typing. Standardized procedures for identification of relevant genes and of variation are needed to enable comparison between studies and over...... genomes and evaluate their value as typing targets, comparing whole genome typing and traditional methods such as 16S and MLST. A consensus tree based on variation of core genes gives much better resolution than 16S and MLST; the pan-genome family tree is similar to the consensus tree, but with higher...... that there is a positive selection towards mutations leading to amino acid changes. Conclusions: Genomic variation within the core genome is useful for investigating molecular evolution and providing candidate genes for bacterial genome typing. Identification of genes with different degrees of variation is important...

  10. Thermoelastic properties of sandwich materials with pin-reinforced foam cores

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Pin-reinforced foam is a novel type of sandwich core materials formed by inserting pins(trusses) into a foam matrix to create a truss-like network reinforced foam core.Upon loading,the pins deform predominantly by local stretching whilst the deformation of foam is governed by local bending.This paper presents a theoretical study on the thermoelasticity of pin-reinforced foam sandwich cores.To calculate the effective thermoelastic properties of pin-reinforced foam cores,the energy-based homogenization approach is employed to develop a micromechanics-based model,calibrated by the existing experimental data.It is found that the stiffness of the sandwich core is mainly governed by pin reinforcements:the foam matrix contributes little to sandwich stiffness.Compared with traditional foam cores without pin reinforcements,the changes in inplane thermal expansion coefficients are not vigorous as a result of pin reinforcements,while the through-thickness thermal expansion coefficient changes significantly.It is also demonstrated that it is possible to design materials with zero or negative thermal expansion coefficients under such a context.

  11. Thermoelastic properties of sandwich materials with pin-reinforced foam cores

    Institute of Scientific and Technical Information of China (English)

    LU TianJian; LIU Tao; DENG ZiChen

    2008-01-01

    Pin-reinforced foam is a novel type of sandwich core materials formed by inserting pins (trusses) into a foam matrix to create a truss-like network reinforced foam core. Upon loading, the pins deform predominantly by local stretching whilst the defor-mation of foam is governed by local bending. This paper presents a theoretical study on the thermoelasllcity of pin-reinforced foam sandwich cores. To calculate the effective thermoelastic properties of pin-reinforced foam cores, the energy-based homogenization approach is employed to develop a micromechanics-based model, calibrated by the existing experimental data. It is found that the stiffness of the sandwich core is mainly governed by pin reinforcements: the foam matrix con-tributes little to sandwich stiffness. Compared with traditional foam cores without pin reinforcements, the changes in in-plane thermal expansion coefficients are not vigorous as a result of pin reinforcements, while the through-thickness thermal expansion coefficient changes significantly. It is also demonstrated that it is pos-sible to design materials with zerO or negative thermal expansion coefficients un-der such a context.

  12. Selection of material for cores hardened with carbon dioxide

    Directory of Open Access Journals (Sweden)

    M. S. Soiński

    2007-04-01

    Full Text Available The work presents the investigation results concerning the bending and the tensile strength of specimens made of various types of core sands. The investigated core sands for bending tests have been prepared of silica sand from Nowogród Dobrzański and, alternatively, of H33 German sand, both containing a variety of binders, namely Carbophen 5692, Carbophen 7170, Carbophen 8178, Novatec 1000, or SuperEko 2000 phenolic resins, as well as water glass. The tensile strength has been investigated for specimens made of silica sand from Nowogród Dobrzański and the sand supplied by Hüttenes-Albertus Polska, both types bond with Carbophen 5692, Novatec 1000, or SuperEko 2000 resins. All specimens have been tested immediately after the CO2 hardening process, then after 1 hour and after 24 hours. It has been found that the type of sand grains significantly affects both the bending and the tensile strength. Furthermore, for each type of sand the best bending strength has been achieved for Carbophen 7170, Carbophen 8178, and Novatec 1000 resins, whereas the best tensile strength has been offered by specimens bond with Carbophen 5692 resin.

  13. Standard Test Method for Shear Fatigue of Sandwich Core Materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This test method covers determination of the effect of repeated shear loads on sandwich core materials. 1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units given may be approximate. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  14. Piezoelectric material for use in a nuclear reactor core

    Science.gov (United States)

    Parks, D. A.; Reinhardt, Brian; Tittmann, B. R.

    2012-05-01

    In radiation environments ultrasonic nondestructive evaluation has great potential for improving reactor safety and furthering the understanding of radiation effects and materials. In both nuclear power plants and materials test reactors, elevated temperatures and high levels of radiation present challenges to ultrasonic NDE methodologies. The challenges are primarily due to the degradation of the ultrasonic sensors utilized. We present results from the operation of a ultrasonic piezoelectric transducer, composed of bulk single crystal AlN, in a nuclear reactor core for over 120 MWHrs. The transducer was coupled to an aluminum cylinder and operated in pulse echo mode throughout the irradiation. In addition to the pulse echo testing impedance data were obtained. Further, the piezoelectric coefficient d33 was measured prior to irradiation and found to be 5.5 pC/N which is unchanged from as-grown samples, and in fact higher than the measured d33 for many as-grown samples.

  15. Materials Assessment for the Canadian SCWR Core Concept

    Science.gov (United States)

    Zheng, Wenyue; Guzonas, David; Boyle, Kevin P.; Li, Jian; Xu, Su

    2016-02-01

    As part of the development effort of the Generation IV Forum, Canada has undertaken research to support the conceptual design of a pressure-tube-based supercritical water-cooled reactor (SCWR). With an outlet temperature of 625°C and a coolant pressure of 25 MPa, this concept requires fuel-cladding materials that can sustain very harsh in-core conditions. After reviewing the worldwide efforts in SCWR materials since the 1950s, a materials program was created to identify and assess candidate alloys that have potential to operate for 3.5 years as a fuel cladding. An overview of the key aspects and the overall results of this program are presented in this paper, while detailed discussions of individual projects in this program are provided in the accompanying papers of this issue. Further materials R&D work should focus on improving the resistance to stress corrosion cracking, high-temperature strength and ductility as well as microstructural stability.

  16. Characterization of sialon-type materials

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, P.N.

    1977-06-01

    Four sialon-type materials using volcanic ash as a raw material were characterized and some of their properties were determined. The M3 and M4 materials were identified as ..beta../sup 1/--Si/sub 3/N/sub 4/ sialons; their principal constituent is silicon. The M2 material was identified as a 15R-A1N polytype sialon whose principal constituent is aluminum. The M1 material is a mixture of the two types. An overview of results showing the general structural formulae and the relative order of the materials with respect to various properties as determined by the investigation is presented. It is concluded that of the materials tested, the M2 material shows the most promise as a candidate for meeting some of the current needs for high-temperature materials. It is also concluded that more research is needed in order to explain the low resistance of these materials to thermal shock since their coefficients of thermal expansion are relatively low.

  17. Standard Test Method for Water Absorption of Core Materials for Structural Sandwich Constructions

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2001-01-01

    1.1 This test method covers the determination of the relative amount of water absorption by various types of structural core materials when immersed or in a high relative humidity environment. This test method is intended to apply to only structural core materials; honeycomb, foam, and balsa wood. 1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units given may be approximate. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  18. Type material in the NCBI Taxonomy Database.

    Science.gov (United States)

    Federhen, Scott

    2015-01-01

    Type material is the taxonomic device that ties formal names to the physical specimens that serve as exemplars for the species. For the prokaryotes these are strains submitted to the culture collections; for the eukaryotes they are specimens submitted to museums or herbaria. The NCBI Taxonomy Database (http://www.ncbi.nlm.nih.gov/taxonomy) now includes annotation of type material that we use to flag sequences from type in GenBank and in Genomes. This has important implications for many NCBI resources, some of which are outlined below.

  19. Irradiation-Accelerated Corrosion of Reactor Core Materials. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Zhujie [Univ. of Michigan, Ann Arbor, MI (United States); Was, Gary [Univ. of Michigan, Ann Arbor, MI (United States); Bartels, David [Univ. of Notre Dame, IN (United States)

    2015-04-02

    This project aims to understand how radiation accelerates corrosion of reactor core materials. The combination of high temperature, chemically aggressive coolants, a high radiation flux and mechanical stress poses a major challenge for the life extension of current light water reactors, as well as the success of most all GenIV concepts. Of these four drivers, the combination of radiation and corrosion places the most severe demands on materials, for which an understanding of the fundamental science is simply absent. Only a few experiments have been conducted to understand how corrosion occurs under irradiation, yet the limited data indicates that the effect is large; irradiation causes order of magnitude increases in corrosion rates. Without a firm understanding of the mechanisms by which radiation and corrosion interact in film formation, growth, breakdown and repair, the extension of the current LWR fleet beyond 60 years and the success of advanced nuclear energy systems are questionable. The proposed work will address the process of irradiation-accelerated corrosion that is important to all current and advanced reactor designs, but remains very poorly understood. An improved understanding of the role of irradiation in the corrosion process will provide the community with the tools to develop predictive models for in-reactor corrosion, and to address specific, important forms of corrosion such as irradiation assisted stress corrosion cracking.

  20. Combining Slater-type orbitals and effective core potentials

    Science.gov (United States)

    Lesiuk, Michał; Tucholska, Aleksandra M.; Moszynski, Robert

    2017-05-01

    We present a general methodology to evaluate matrix elements of the effective core potentials (ECPs) within a one-electron basis set of Slater-type orbitals (STOs). The scheme is based on translation of individual STO distributions in the framework of the Barnett-Coulson method. We discuss different types of integrals which naturally appear and reduce them to a few basic quantities which can be calculated recursively or purely numerically. Additionally, we consider evaluation of the STOs matrix elements involving the core polarization potentials and effective spin-orbit potentials. Construction of the STOs basis sets designed specifically for use with ECPs is discussed and differences in comparison with all-electron basis sets are briefly summarized. We verify the validity of the present approach by calculating excitation energies, static dipole polarizabilities, and valence orbital energies for the alkaline-earth metals (Ca, Sr, and Ba). Finally, we evaluate interaction energies, permanent dipole moments, and ionization energies for barium and strontium hydrides, and compare them with the best available experimental and theoretical data.

  1. Comparative evaluation of compressive strength and flexural strength of conventional core materials with nanohybrid composite resin core material an in vitro study.

    Science.gov (United States)

    Jayanthi, Narasimha; Vinod, V

    2013-09-01

    Several dental materials have been used for core build-up procedures. Most of these materials were not specifically developed for this purpose, but as a consequence of their properties, have found application in core build-up procedures. Improvements in composites and the development of nanocomposites have led to their use as a core build up material due to their superior mechanical properties, optical properties and ease of handling. However it is not clear if they have better mechanical properties than the conventional core build up materials like amalgam, GIC and dual cure composite core build up material. The strength of the core material is very important and this study was undertaken to compare the mechanical properties of materials used for direct core foundations. The differences between the compressive strength and flexural strength of Filtek Z350 nanocomposite with conventional core build up materials like Amalgam, Vitremer GIC and Fluorocore were tested. Cylindrical plexi glass split molds of dimension 6 ± 1 mm [height] x4 ± 1 mm [diameter] were used to fabricate 15 samples of each core material for testing the compressive strength and rectangular plexi glass split molds of dimension 25 ± 1 mm [length] x 2 ± 1 mm[height] x2 ± 1 mm [width] used for fabricating samples for flexural strength. The samples were stored a water bath at 250 °C for 24 h before testing. The samples were tested using a Universal Instron testing machine. The results of the study showed that Fluorocore had the highest compressive strength and flexural strength followed by Filtek Z350 [nanocomposite] Amalgam had the least flexural strength and Vitremer GIC had the least compressive strength. Thus flurocore and nanocomposite are stronger than other core build up materials and hence should be preferred over other conventional core build up materials in extensively damaged teeth.

  2. Multispecies Biofilm Development on Space Station Heat Exhanger Core Material

    Science.gov (United States)

    Pyle, B. H.; Roth, S. R.; Vega, L. M.; Pickering, K. D.; Alvarez, Pedro J. J.; Roman, M. C.

    2007-01-01

    Investigations of microbial contamination of the cooling system aboard the International Space Station (ISS) suggested that there may be a relationship between heat exchanger (HX) materials and the degree of microbial colonization and biofilm formation. Experiments were undertaken to test the hypothesis that biofilm formation is influenced by the type and previous exposure of HX surfaces. Acidovorax delafieldii, Comamonas acidovorans, Hydrogenophaga pseudoflava, Pseudomonas stutzeri, Sphingomonas paucimobilis, and Stenotrophomonas maltophilia, originally isolated from ISS cooling system fluid, were cultured on R2A agar and suspended separately in fresh filter-sterilized ISS cooling fluid, pH 8.3. Initial numbers in each suspension ranged from 10(exp 6)-10(exp 7) CFU/ml, and a mixture contained greater than 10(exp 7) CFU/ml. Coupons of ISS HX material, previously used on orbit (HXOO) or unused (HXUU), polycarbonate (PC) and 316L polished stainless steel (SS) were autoclaved, covered with multispecies suspension in sterile tubes and incubated in the dark at ambient (22-25 C). Original HX material contained greater than 90% Ni, 4.5% Si, and 3.2% B, with a borate buffer. For approximately 10 weeks, samples of fluid were plated on R2A agar, and surface colonization assessed by SYBR green or BacLight staining and microscopy. Suspension counts for the PC and SC samples remained steady at around 10(exp 7) CFU/ml. HXUU counts declined about 1 log in 21 d then remained steady, and HXOO counts declined 2 logs in 28 d, fluctuated and stabilized about 10(exp 3) CFU/ml from 47-54 d. Predominantly yellow S. paucimobilis predominated on plates from HXOO samples up to 26 d, then white or translucent colonies of other species appeared. All colony types were seen on plates from other samples throughout the trial. Epifluorescence microscopy indicated microbial growth on all surfaces by 21 d, followed by variable colonization. After 54 d, all but the HXOO samples had well

  3. Explaining the Type Ia Supernova PTF 11kx with the Core Degenerate Scenario

    CERN Document Server

    Soker, Noam; Garcia-Berro, Enrique; Torres, Santiago; Camacho, Judit

    2012-01-01

    We argue that the multiple shells of circumstellar material (CSM) and the supernovae (SN) ejecta interaction with the CSM starting 59 days after the explosion of the Type Ia SN (SN Ia) PTF 11kx, are best described by the core-degenerate (CD) scenario for SN Ia. In the CD scenario the super-Chandrasekhar mass white dwarf (WD) is formed at the termination of the common envelope phase from a merger of a WD companion with the hot core of a massive asymptotic giant branch (AGB) star. In most cases the WD is destructed and accreted onto the more massive core. However, in rare cases where mergers take place when the WD is denser than the core, the core will be destructed and accreted onto the cooler WD. In such cases the explosion might occur with no appreciable delay, i.e., months to years after the termination of the common envelope (CE) phase. This, we propose, is the evolutionary route that lead to the explosion of PTF 11kx. The CD scenario can account for the very massive CSM within ~1000 AU of the exploding PT...

  4. Scaling of Core Material in Rubble Mound Breakwater Model Tests

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Z.; Troch, P.

    1999-01-01

    correct scaling. The paper presents an empirical formula for the estimation of the wave induced pressure gradient in the core, based on measurements in models and a prototype. The formula, together with the Forchheimer equation can be used for the estimation of pore velocities in cores. The paper proposes...

  5. Galois Corings and a Jacobson-Bourbaki type Correspondence

    OpenAIRE

    Cuadra, J.; Gomez-Torrecillas, J.

    2005-01-01

    The Jacobson-Bourbaki Theorem for division rings was formulated in terms of corings by Sweedler in 1975. Finiteness conditions hypotheses are not required in this new approach. In this paper we extend Sweedler's result to simple artinian rings using a particular class of corings, comatrix corings. A Jacobson-Bourbaki like correspondence for simple artinian rings is then obtained by duality.

  6. Core and Valence Structures in K beta X-ray Emission Spectra of Chromium Materials

    NARCIS (Netherlands)

    Torres Deluigi, Maria; de Groot, Frank M. F.|info:eu-repo/dai/nl/08747610X; Lopez-Diaz, Gaston; Tirao, German; Stutz, Guillermo; Riveros de la Vega, Jose

    2014-01-01

    We analyze the core and valence transitions in chromium in a series of materials with a number of different ligands and including the oxidation states: Cr-II, Cr-III, Cr-IV, and Cr-VI. To study the core-to-core transitions we employ the CTM4XAS program and investigate the shapes, widths,

  7. 核壳吸波材料的研究进展∗%Progress in core-shell absorbing materials

    Institute of Scientific and Technical Information of China (English)

    俞梁; 王建江; 许宝才; 李志广; 蔡旭东

    2015-01-01

    As a new core-shell composite absorbing material,as compared with a single type of absorbing mate-rial in the structure,properties and applications of absorbing has obvious advantages,the paper summarizes the basic types of core-shell absorbing materials,preparation methods and proposed a new method for self-reactive quenching + surface modification method.Pointed out that the core-shell absorbing material absorbing material is expected to meet the new"thin,light,wide,strong"requirements,and core-shell absorbing materials re-search proposed future prospects.%核壳吸波材料作为一种新型复合吸波材料,与单一类型的吸波材料相比在结构、吸波性能和应用上有着明显优势,本文总结了核壳吸波材料的基本类型、制备方法及提出了一种新的制备方法-自反应淬熄+表面改性法。指出核壳吸波材料有望满足新型吸波材料“薄、轻、宽、强”的要求,并对今后核壳吸波材料的研究提出展望。

  8. Resistance of core materials against torsional forces on differently conditioned titanium posts

    NARCIS (Netherlands)

    Akisli, [No Value; Ozcan, M; Nergiz, [No Value

    2002-01-01

    Statement of problem. The separation of core materials from titanium posts, which have a low modulus of elasticity, has been identified as a problem in restorative dentistry. Purpose. This study evaluated the resistance to torsional forces of various core materials adapted to differently conditioned

  9. Comparative evaluation of bond strengths of different core materials with various luting agents used for cast crown restorations.

    Science.gov (United States)

    Nayakar, Ramesh P; Patil, Narendra P; Lekha, K

    2012-09-01

    The coronal cast restoration continues to be used commonly to restore mutilated, endodontically treated teeth. The tensile bond strength of luting cements is of critical importance as many of failures are at the core and the crown interface. An invitro study with aim to evaluate and compare bond strengths of luting cements between different core materials and cast crowns. A total of 45 extracted identical mandibular second premolars were endodontically treated and divided into 3 groups of 15 each. Specimens in first group were restored with cast post and core (Group C), and specimens in second group were restored with stainless steel parapost and composite core material (Group B) and specimens in third group were restored with stainless steel parapost and glass ionomer core build (Group G). Standardized crown preparation was done for all the specimens to receive cast crowns. Each group was further divided into 3 subgroups and were cemented using 3 different luting cements namely, resin cement, polycarboxylate cement, glass ionomer cement (Type I). The samples of each subgroup (n = 5) were subjected to tensile testing using Universal Testing Machine at a crosshead speed of 2 mm/min till the dislodgement of crown from the core surface was observed. The bond strengths were significantly different according one way ANOVA (F-150.76 and p < 0.0000). The results of the study showed that the specimens cemented with resin cement in cast core, composite core and glass ionomer core exhibited significantly higher bond strengths as compared to specimens cemented with glass ionomer and polycarboxylate cement. Composite resin core and resin cement combinations were superior to all other cement and core combinations tested.

  10. Selection of Soft Magnetic Core Materials Used on an LVDT Prototype

    Directory of Open Access Journals (Sweden)

    R. Yañez-Valdez

    2012-04-01

    Full Text Available Traditionally, the use of ferrite as a core of the linear variable differential transformer (LVDT is suggested in its designs. Nevertheless, problems related to its brittleness and low tensile strength may be considered as important drawbacks for its use as a core material, especially when its geometry is likely to be modified. This work explores other alternatives related to soft magnetic materials, less used in applications of an LVDT core. By means of a decision matrix, from an assortment of different materials, three alternatives were selected. This proposal provides the identification of those materials with higher qualification values to be used as core material. In order to validate the performance of the selected materials, a prototype of LVDT was designed and fabricated. The design was carried out taking into consideration typical performance specifications. Finally, a comparison of the measurements of sensitivity and linearity of the proposed and traditional materials was made.

  11. Preliminary study of degradation from neutron effects of core-structural materials of Thai Research Reactor TRR-1/M1

    Science.gov (United States)

    Ampornrat, P.; Boonsuwan, P.; Sangkaew, S.; Angwongtrakool, T.

    2017-06-01

    Thai research reactor went first critical in 1962. The reactor was converted in 1977 from an MTR-type with high-enriched uranium fuel to a TRIGA-MARK III type using low-enriched uranium fuel, called TRR-1/M1. Since the TRR-1/M1 has been operated for almost 40 years, degradation of reactor structural materials is expected. In this preliminary study, the potential degradation from neutron effects of core-structural materials, e.g., fuel clad (SS304) and core components (Al6061) were studied. Assessment included calculation of neutron energy, flux and fluence in the reactor core to evaluate displacement rate (dpa) and irradiation effects on the material properties. Results showed maximum displacement rates on SS304 was 5.24×10-8 per cm3·sec and on Al6061 was 1.14×10-8 per cm3·sec. The corresponding maximum displacement levels were ∼17 dpa for SS304, and ∼4 dpa for Al6061. At these levels of displacement, it is possible for the materials to result in tensile strength increasing and ductility reduction. Further inspection on the core-structural materials needs to be conducted to validate the assessment results from this study.

  12. π-Core tailoring for new high performance thieno(bis)imide based n-type molecular semiconductors.

    Science.gov (United States)

    Durso, Margherita; Gentili, Denis; Bettini, Cristian; Zanelli, Alberto; Cavallini, Massimiliano; De Angelis, Filippo; Grazia Lobello, Maria; Biondo, Viviana; Muccini, Michele; Capelli, Raffaella; Melucci, Manuela

    2013-05-14

    The synthesis and characterization of two thieno(bis)imide based n-type semiconductors with electron mobilities of up to 0.3 cm(2) V(-1) s(-1) are described. The relationships between the electronic features of the π-inner core and the functional properties of the new materials are also discussed.

  13. In vitro evaluation of the fracture strength of all-ceramic core materials on zirconium posts.

    Science.gov (United States)

    Ozcan, Nihal; Sahin, Erdal

    2013-10-01

    For most endodontically treated teeth, tooth-colored post-core systems are preferable for esthetic reasons. Therefore, improvements in material strength must also consider tooth colored post-core complexes. The objective of this study was to evaluate the difference in tooth colored post-core complex strengths. A total of 33 human maxillary central incisor teeth were used for this study, with three groups of 11 teeth. Three different methods were used to fabricate all-ceramic post-core restorations: zirconia blanks, Cerec 3D-milled to one-piece post-core restorations (Test Group 1); feldspathic cores (from feldspathic prefabricated CAD/CAM blocks) adhesively luted to CosmoPost zirconia posts (Test Group 2); and IPS Empress cores directly pressed to CosmoPost zirconia posts (Test Group 3). All-ceramic crowns from feldspathic ceramic were constructed using a CAD/CAM system (Cerec 3D) for all specimens. The post-core complexes were tested to failure with the load applied at 45° angled relative to the tooth long axis. The load at fracture was recorded. The maximum fracture strength of the milled zirconia cores (Test Group 1) was 577 N; corresponding values for the milled feldspathic cores (Test Group 2) and the pressed cores (Test Group 3) were 586 and 585 N, respectively. Differences were not statistically significant at P cores adhesively luted on zirconia posts and one-piece all-ceramic zirconium post-core structures offer a viable alternative to conventional pressing.

  14. Solid0Core Heat-Pipe Nuclear Batterly Type Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ehud Greenspan

    2008-09-30

    This project was devoted to a preliminary assessment of the feasibility of designing an Encapsulated Nuclear Heat Source (ENHS) reactor to have a solid core from which heat is removed by liquid-metal heat pipes (HP).

  15. Antistatic coating material consisting of poly (butylacrylate-co-styrene) core-nickel shell particle

    Institute of Scientific and Technical Information of China (English)

    Min-Yeong JEONG; Byung-Yoon AHN; Sang-Koul LEE; Won-Ki LEE; Nam-Ju JO

    2009-01-01

    A transparent and antistatic coating material consisting of polymer core-metal shell particle was prepared. As a polymer core, poly(butylacrylate-co-styrene)s ([P(BA-co-sty)s]) with various compositions of butylacrylate and styrene were synthesized by emulsion polymerization. And the effect of comonomer composition on the thermal property of polymer core particle was investigated. By electroless plating method, the nickel particles were formed and deposited on the surface of P(BA-co-Sty) particles to form P(BA-co-Sty) core-nickel shell composite particles. SEM observation confirms that the nickel particles with size of 15 nm are distributed on the surface of the polymer core particles. The surface resistance of P(BA-co-Sty) core-nickel shell composite is 0.8×108Ω/cm2, enough to act as antistatic coating material.

  16. Effect of Three Different Core Materials on Masking Ability of a Zirconia Ceramic

    Directory of Open Access Journals (Sweden)

    Farhad Tabatabaian

    2016-12-01

    Full Text Available Objectives: Masking ability of a restorative material plays a role in hiding colored substructures; however, the masking ability of zirconia ceramic (ZRC has not yet been clearly understood in zirconia-based restorations. This study evaluated the effect of three different core materials on masking ability of a ZRC.Materials and Methods: Ten zirconia disc samples, 0.5mm in thickness and 10mm in diameter, were fabricated. A white (W substrate (control and three substrates of nickel-chromium alloy (NCA, non-precious gold alloy (NPGA, and ZRC were prepared. The zirconia discs were placed on the four types of substrates for spectrophotometry. The L*, a*, and b* values of the specimens were measured by a spectrophotometer and color change (ΔE values were calculated to determine color differences between the test and control groups and were then compared with the perceptual threshold. Randomized block ANOVA and Bonferroni test analyzed the data. A significance level of 0.05 was considered.Results: The mean and standard deviation values of ΔE for NCA, NPGA, and ZRC groups were 10.26±2.43, 9.45±1.74, and 6.70±1.91 units, respectively. Significant differences were found in the ΔE values between ZRC and the other two experimental groups (NCA and NPGA; P<0.0001 and P=0.001, respectively. The ΔE values for the groups were more than the predetermined perceptual threshold.Conclusions: Within the limitations of this study, it was concluded that the tested ZRC could not well mask the examined core materials.Keywords: Color; Spectrophotometry; Visual Perception; Yttria Stabilized Tetragonal Zirconia

  17. Microscopic findings in EUS-guided fine needle (SharkCore) biopsies with type 1 and type 2 autoimmune pancreatitis

    DEFF Research Database (Denmark)

    Detlefsen, Sönke; Joergensen, Maiken Thyregod; Mortensen, Michael Bau

    2017-01-01

    The International Consensus Diagnostic Criteria (ICDC) for the diagnosis of autoimmune pancreatitis (AIP) include the histological criterion that is based on either pancreatic core needle biopsies (CNBs) or surgical specimens. However, CNBs are difficult to obtain by endoscopic ultrasound (EUS......). EUS fine-needle aspiration (EUS-FNA) cytology is usually not sufficient for the diagnosis of AIP, but may sometimes contain tissue microfragments. Another approach is EUS-guided histological fine-needle biopsy (EUS-FNB), using needles such as the SharkCore or ProCore needle. Published data regarding...... EUS-guided SharkCore FNB for the diagnosis of AIP are lacking. We aimed to describe our histological findings in one type 1 and two type 2 AIP patients who underwent EUS SharkCore FNB. The EUS-FNBs of two patients fulfilled the histological level 2 ICDC for type 1 AIP or type 2 AIP. The EUS-FNB of one...

  18. First-principles predictions of potential hydrogen storage materials: Nanosized Ti(core)/Mg(shell) hydrides

    Science.gov (United States)

    Tao, S. X.; Notten, P. H. L.; van Santen, R. A.; Jansen, A. P. J.

    2011-05-01

    MgH2 is one of the most promising hydrogen storage materials. However MgH2 is thermodynamicly too stable, leading to a too high desorption temperature of 300°C at atmospheric pressure, which is a major impediment for practical applications. In this study, aiming to tune the thermodynamic stability of the MgH2, nanosized two-dimensional Mg/Ti/Mg sandwich and three-dimensional Ti(core)/Mg(shell) hydrides have been investigated by using density functional theory calculations. For both structures, four types of hydrogen atoms can be distinguished: on the surface of the Mg (Hsurf), within the Mg (HMg), at the Mg/Ti interface (HMgTi), and within the Ti (HTi). For the dehydrogenation reaction, the hydrogen desorption from the hydride is in the order Hsurf, HMg, HMgTi, HTi. The desorption energy of Hsurf is unexpectedly high. As expected, due to the well-preserved fluorite structure of the partially hydrogenated hydride, the desorption energy of HMg is significantly lower than that of bulk rutile MgH2. The further desorption of HMgTi and HTi becomes more difficult due to the strong Ti-H bonding. We propose that partial hydrogenation without adsorption of Hsurf and partial dehydrogenation without desorption of HMgTi and HTi would keep the fluorite symmetry with its favorable thermodynamics. The reversible hydrogen capacity (HMg) of the Mg/Ti/Mg sandwich structure is low, whereas the reversible hydrogen capacity of the Ti(core)/Mg(shell) is calculated to be reasonable high. Our results predicted Ti(core)/Mg(shell) structures are potential useful materials for hydrogen storage application.

  19. Standard Test Method for Dimensional Stability of Sandwich Core Materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 This test method covers the determination of the sandwich core dimensional stability in the two plan dimensions. 1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units given may be approximate. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  20. Multifunctional Core Materials for Airframe Primary Structures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — As the use of composite materials on commercial airlines grows the technology of the composites must grow with it. Presently the efficiency gained by the utilization...

  1. Magnetic and Electrical Characteristics of Cobalt-Based Amorphous Materials and Comparison to a Permalloy Type Polycrystalline Material

    Science.gov (United States)

    Wieserman, William R.; Schwarze, Gene E.; Niedra, Janis M.

    2005-01-01

    Magnetic component designers are always looking for improved soft magnetic core materials to increase the efficiency, temperature rating and power density of transformers, motors, generators and alternators, and energy density of inductors. In this paper, we report on the experimental investigation of commercially available cobalt-based amorphous alloys which, in their processing, were subjected to two different types of magnetic field anneals: A longitudinal magnetic field anneal or a transverse magnetic field anneal. The longitudinal field annealed material investigated was Metglas 2714A. The electrical and magnetic characteristics of this material were investigated over the frequency range of 1 to 200 kHz and temperature range of 23 to 150 C for both sine and square wave voltage excitation. The specific core loss was lower for the square than the sine wave voltage excitation for the same maximum flux density, frequency and temperature. The transverse magnetic field annealed core materials include Metglas 2714AF and Vacuumschmelze 6025F. These two materials were experimentally characterized over the frequency range of 10 to 200 kHz for sine wave voltage excitation and 23 C only. A comparison of the 2174A to 2714AF found that 2714AF always had lower specific core loss than 2714A for any given magnetic flux density and frequency and the ratio of specific core loss of 2714A to 2714AF was dependent on both magnetic flux density and frequency. A comparison was also made of the 2714A, 2714AF, and 6025F materials to two different tape thicknesses of the polycrystalline Supermalloy material and the results show that 2714AF and 6025F have the lowest specific core loss at 100 kHz over the magnetic flux density range of 0.1 to 0.4 Tesla.

  2. Propagation of combustion waves in the shell-core energetic materials with external heat losses.

    Science.gov (United States)

    Gubernov, V V; Kudryumov, V N; Kolobov, A V; Polezhaev, A A

    2017-03-01

    In this paper, the properties and stability of combustion waves propagating in the composite solid energetic material of the shell-core type are numerically investigated within the one-dimensional diffusive-thermal model with heat losses to the surroundings. The flame speed is calculated as a function of the parameters of the model. The boundaries of stability are determined in the space of parameters by solving the linear stability problem and direct integration of the governing non-stationary equations. The results are compared with the characteristics of the combustion waves in pure solid fuel. It is demonstrated that a stable travelling combustion wave solution can exist for the parameters of the model for which the flame front propagation is unstable in pure solid fuel and it can propagate several times faster even in the presence of significant heat losses.

  3. Techniques and Apparatus for Measuring Rotational Core Losses of Soft Magnetic Materials

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In many situations such as the cores of a rotating electrical machine and the T joints of a multiphase transformer, the local flux density varies with time in terms of both magnitude and direction, i.e. the flux density vector is rotating. Therefore, the magnetic properties of the core materials under the rotating flux density vector excitation should be properly measured, modeled and applied in the design and analysis of these electromagnetic devices. This paper presents an extensive review on the development of techniques and apparatus for measuring the rotational core losses of soft magnetic materials based on the experiences of various researchers in the last hundred years.

  4. The Effect of Cyclic Loading on the Compressive Strength of Core Build-Up Materials.

    Science.gov (United States)

    Zankuli, Muayed A; Silikas, Nick; Devlin, Hugh

    2015-01-15

    To evaluate the effect of cyclic loading on compressive strength of core build-up materials. Four dual-cured composites (Core.X Flow, Grandio Core, Bright Flow Core, Spee-Dee) and one light-cured reinforced resin-modified glass ionomer (Fuji II LC) were tested. One hundred cylindrical specimens (4 mm × 6 mm) were prepared. Each material had two groups (ten specimens to be tested under static loading and ten specimens to be tested after cyclic loading). The specimens were stored wet, and after 30 days, one group of each material was cyclically loaded (for 250,000 cycles with a frequency of 1.6 Hz under stress load of 68.6 N) in a chewing simulator CS-4.2. Then specimens were subjected to static compressive loading until failure in a universal testing machine. Mean compressive strength values before cycling ranged from 144 MPa (15.8) for Fuji II LC to 277 MPa (23.2) for Grandio Core. Independent t-test showed no statistically significant difference (p > 0.05) in the compressive strength of each material before and after cycling (p = 0.7 Grandio Core, p = 0.3 Core.X Flow, p = 0.6 Bright Flow Core, p = 0.2 Spee-Dee, p = 0.6 Fuji II LC); however, there was a statistically significant difference between the materials when comparing before and after cycling. All tested materials showed no reduction in the compressive strength after cycling. Therefore, the tested materials can survive 1 year in service without a reduction in compressive strength. © 2015 by the American College of Prosthodontists.

  5. Relationships Between Complex Core Level Spectra and Materials Properties

    Energy Technology Data Exchange (ETDEWEB)

    Nelin, Constance J.; Bagus, Paul S.; Ilton, Eugene S.; Chambers, Scott A.; Kuhlenbeck, Helmut; Freund, Hans-Joachim

    2010-12-01

    The XPS of many oxides are quite complex and there may be several peaks of significant intensity for each subshell. These peaks arise from many-electron effects, which normally are treated with configuration interaction (CI) wavefunctions where static correlation effects are taken into account. It is common to use semiempirical methods to determine the matrix elements of the CI Hamiltonian and there are few rigorous CI calculations where parameters are not adjusted to fit experiment. In contrast, we present, in the present work, theoretical XPS spectra obtained with rigorous CI wavefunctions for CeO2 where the XPS are especially complex; several different core levels are studied. This study uses an embedded CeO8 cluster model to represent bulk CeO2 and the relativistic CI wavefunctions are determined using four-component spinors from Dirac-Fock calculations. In particular, we examine the importance of interatomic many-body effects where there is a transfer of electrons from occupied oxygen 2p orbitals into empty cation orbitals as it is common to ascribe the complex XPS to this effect. We also contrast the importance of many-body charge-transfer effects for the isoelectronic cations of Ce4+ and La3+. The long-range goal of this work is to relate the XPS features to the nature of the chemical bonding in CeO2 and we describe our progress toward this goal.

  6. Investigation of the exciton emission lifetime in type-II spherical core/shell semiconductor heteronanostructures

    Science.gov (United States)

    Arfaoui, A.; Mahdouani, M.; Bourguiga, R.

    2017-08-01

    The two-band model effective mass approximation has been adopted to explain the energy spectra in type-I CdSe core-only and type-II CdSe/CdTe core/shell quantum dots (QDs). As optical properties, the emission wavelength, the electron-hole overlap integral and the radiative recombination lifetime have been investigated. The simulated emission spectra are in good agreement with available experimental results for both core-only and core/shell QDs. The radiative recombination lifetime (τrad) has been investigated in different carrier localization regimes and compared to that corresponding to core-only QDs. We have found a sudden increase in τrad at around r1 1.1 nm suggesting the transition of the heterostructure from the quasi-type-II to the type-II regime. A monotonic increase in τrad with the core and shell sizes (geometric parameters) was observed. Also found is the possibility of increasing τrad over two orders of magnitude with a suitable change in the geometric parameters. The long radiative lifetime produced by increasing the geometric parameters is found due to spatial separation of the carriers, which makes the type-II core/shell QDs made from large core and shell sizes promising for photovoltaic applications.

  7. Computational Design and Analysis of Core Material of Single-Phase Capacitor Run Induction Motor

    Directory of Open Access Journals (Sweden)

    Gurmeet Singh

    2014-07-01

    Full Text Available A Single-phase induction motor (SPIM has very crucial role in industrial, domestic and commercial sectors. So, the efficient SPIM is a foremost requirement of today's market. For efficient motors, many research methodologies and propositions have been given by researchers in past. Various parameters like as stator/rotor slot variation, size and shape of stator/rotor slots, stator/rotor winding configuration, choice of core material etc. have momentous impact on machine design. Core material influences the motor performance to a degree. Magnetic flux linkage and leakage preliminary depends upon the magnetic properties of core material and air gap. The analysis of effects of core material on the magnetic flux distribution and the performance of induction motor is of immense importance to meet out the desirable performance. An increase in the air gap length will result in the air gap performance characteristics deterioration and decrease in air gap length will lead to serious mechanical balancing concern. So possibility of much variation in air gap beyond the limits on both sides is not feasible. For the optimized performance of the induction motor the core material plays a significant role. Using higher magnetic flux density, reduction on a magnetizing reactance and leakage of flux can be achieved. In this thesis work the analysis of single phase induction motor has been carried out with different core materials. The four models have been simulated using Ansys Maxwell 15.0. Higher flux density selection for same machine dimensions result into huge amount of reduction in iron core losses and thereby improve the efficiency. In this paper 2% higher efficiency has been achieved with Steel_1010 as compared to the machine using conventional D23 material. Out of four models result reflected by the machine using steel_1010 and steel_1008 are found to be better.

  8. Experimental study of the mechanical behaviour of pin reinforced foam core sandwich materials under shear load

    Science.gov (United States)

    Dimassi, M. A.; Brauner, C.; Herrmann, A. S.

    2016-03-01

    Sandwich structures with a lightweight closed cell hard foam core have the potential to be used in primary structures of commercial aircrafts. Compared to honeycomb core sandwich, the closed cell foam core sandwich overcomes the issue of moisture take up and makes the manufacturing of low priced and highly integrated structures possible. However, lightweight foam core sandwich materials are prone to failure by localised external loads like low velocity impacts. Invisible cracks could grow in the foam core and threaten the integrity of the structure. In order to enhance the out-of-plane properties of foam core sandwich structures and to improve the damage tolerance (DT) dry fibre bundles are inserted in the foam core. The pins are infused with resin and co-cured with the dry fabric face sheets in an out-of-autoclave process. This study presents the results obtained from shear tests following DIN 53294-standard, on flat sandwich panels. All panels were manufactured with pin-reinforcement manufactured with the Tied Foam Core Technology (TFC) developed by Airbus. The effects of pin material (CFRP and GFRP) and pin volume fraction on the shear properties of the sandwich structure and the crack propagation were investigated and compared to a not pinned reference. It has been concluded that the pin volume fraction has a remarkable effect on the shear properties and damage tolerance of the observed structure. Increasing the pin volume fraction makes the effect of crack redirection more obvious and conserves the integrity of the structure after crack occurrence.

  9. Effect of surface conditioning techniques on the resistance of resin composite core materials on titanium posts

    NARCIS (Netherlands)

    Akisli, [No Value; Ozcan, M; Nergiz, [No Value

    2003-01-01

    Objective: This study evaluated the resistance of various post and core materials against torsional forces on differently conditioned titanium posts. Method and materials: One hundred fifty pure titanium posts (DIN 17850-Ti4/3.7065) were conditioned utilizing Silicoater Classical, Silicoater MD,

  10. Comparative study of mechanical properties of direct core build-up materials

    Directory of Open Access Journals (Sweden)

    Girish Kumar

    2015-01-01

    Full Text Available Background and Objectives: The strength greatly influences the selection of core material because core must withstand forces due to mastication and para-function for many years. This study was conducted to evaluate certain mechanical properties of commonly used materials for direct core build-up, including visible light cured composite, polyacid modified composite, resin modified glass ionomer, high copper amalgam, and silver cermet cement. Materials and Methods: All the materials were manipulated according to the manufacturer′s recommendations and standard test specimens were prepared. A universal testing machine at different cross-head speed was used to determine all the four mechanical properties. Mean compressive strength, diametral tensile strength, flexural strength, and elastic modulus with standard deviations were calculated. Multiple comparisons of the materials were also done. Results: Considerable differences in compressive strength, diametral tensile strength, and flexural strength were observed. Visible light cured composite showed relatively high compressive strength, diametral tensile strength, and flexural strength compared with the other tested materials. Amalgam showed the highest value for elastic modulus. Silver cermet showed less value for all the properties except for elastic modulus. Conclusions: Strength is one of the most important criteria for selection of a core material. Stronger materials better resist deformation and fracture provide more equitable stress distribution, greater stability, and greater probability of clinical success.

  11. Effect of surface conditioning techniques on the resistance of resin composite core materials on titanium posts

    NARCIS (Netherlands)

    Akisli, [No Value; Ozcan, M; Nergiz, [No Value

    2003-01-01

    Objective: This study evaluated the resistance of various post and core materials against torsional forces on differently conditioned titanium posts. Method and materials: One hundred fifty pure titanium posts (DIN 17850-Ti4/3.7065) were conditioned utilizing Silicoater Classical, Silicoater MD, Roc

  12. Bond strength of adhesively luted ceramic discs to different core materials.

    Science.gov (United States)

    Bozogullari, Nalan; Inan, Ozgur; Usumez, Aslihan

    2009-05-01

    The purpose of this in vitro study was to compare the shear bond strengths of resin, glass-ionomer, and ceramic-based core materials to all ceramic discs. Five core materials (Core max, Sankin; Clearfil AP-X, Kuraray; Empress Cosmo, Ivoclar-Vivadent; Photocore, Kuraray; Dyract Extra, Dentsply) were prepared as discs 10 mm in diameter and 2 mm in height according to the manufacturer's instructions. Ten disc specimens per group were prepared, and dentin served as the control. All resin specimens were embedded in autopolymerizing acrylic resin, with one surface facing up. All ceramic discs (IPS Empress I, Ivoclar-Vivadent) 3 mm in diameter and 2 mm in height were prepared and bonded to core specimens with a dual-curing luting resin cement (Variolink II, Vivadent). Specimens were stored in distilled water at 37 degrees C. Shear bond strength of each sample was measured after 24 h using a universal testing machine at a crosshead speed of 0.5 mm/min. The data were analyzed with one-way analysis of variance and Tukey HSD tests (alpha = 0.05). Shear bond strength varied significantly depending on the core material used (p strength value while Empress Cosmo provided the lowest (p Core-Max (p > 0.05). And also there were no statistically significant differences between Dyract Extra and the control group (p > 0.05). In vitro shear bond strengths of ceramic discs bonded to resin-based core materials showed higher bond strength values than ceramic-based core material.

  13. Novel magnetic core materials impact modelling and analysis for minimization of RF heating loss

    Science.gov (United States)

    Ghosh, Bablu Kumar; Mohamad, Khairul Anuar; Saad, Ismail

    2016-02-01

    The eddy current that exists in RF transformer/inductor leads to generation of noise/heat in the circuit and ultimately reduces efficiency in RF system. Eddy current is generated in the magnetic core of the inductor/transformer largely determine the power loss for power transferring process. The losses for high-frequency magnetic components are complicated due to both the eddy current variation in magnetic core and copper windings reactance variation with frequency. Core materials permeability and permittivity are also related to variation of such losses those linked to the operating frequency. This paper will discuss mainly the selection of novel magnetic core materials for minimization of eddy power loss by using the approach of empirical equation and impedance plane simulation software TEDDY V1.2. By varying the operating frequency from 100 kHz to 1GHz and magnetic flux density from 0 to 2 Tesla, the eddy power loss is evaluated in our study. The Nano crystalline core material is found to be the best core material due to its low eddy power loss at low conductivity for optimum band of frequency application.

  14. Comparative study of mechanical properties of direct core build-up materials.

    Science.gov (United States)

    Kumar, Girish; Shivrayan, Amit

    2015-01-01

    The strength greatly influences the selection of core material because core must withstand forces due to mastication and para-function for many years. This study was conducted to evaluate certain mechanical properties of commonly used materials for direct core build-up, including visible light cured composite, polyacid modified composite, resin modified glass ionomer, high copper amalgam, and silver cermet cement. All the materials were manipulated according to the manufacturer's recommendations and standard test specimens were prepared. A universal testing machine at different cross-head speed was used to determine all the four mechanical properties. Mean compressive strength, diametral tensile strength, flexural strength, and elastic modulus with standard deviations were calculated. Multiple comparisons of the materials were also done. Considerable differences in compressive strength, diametral tensile strength, and flexural strength were observed. Visible light cured composite showed relatively high compressive strength, diametral tensile strength, and flexural strength compared with the other tested materials. Amalgam showed the highest value for elastic modulus. Silver cermet showed less value for all the properties except for elastic modulus. Strength is one of the most important criteria for selection of a core material. Stronger materials better resist deformation and fracture provide more equitable stress distribution, greater stability, and greater probability of clinical success.

  15. Periodic mesoporous organosilica (PMO) materials with uniform spherical core-shell structure.

    Science.gov (United States)

    Haffer, Stefanie; Tiemann, Michael; Fröba, Michael

    2010-09-10

    We report the synthesis of monodisperse, spherical periodic mesoporous organosilica (PMO) materials. The particles have diameters between about 350 and 550 nm. They exhibit a regular core-shell structure with a solid, non-porous silica core and a mesoporous PMO shell with a thickness of approximately 75 nm and uniform pores of about 1.7 nm. The synthesis of the core and the shell is carried out in a one-pot, two-stage synthesis and can be accomplished at temperatures between 25 and 100 °C. Higher synthesis temperatures lead to substantial shrinking of the solid core, generating an empty void between core and shell. This leads to interesting cavitation phenomena in the nitrogen physisorption analysis at 77.4 K.

  16. A comparative study of the impact properties of sandwich materials with different cores

    Directory of Open Access Journals (Sweden)

    Viot P.

    2012-08-01

    Full Text Available Sandwich panels are made of two high strength skins bonded to either side of a light weight core and are used in applications where high stiffness combined with low structural weight is required. The purpose of this paper is to compare the mechanical response of several sandwich panels whose core materials are different. Sandwich panels with glass fibre-reinforced polymer face sheets were used, combined with five different cores; polystyrene foam, polypropylene honeycomb, two different density Balsa wood and Cork. All specimens were subjected to low velocity impact and their structural response (Force-displacement curves were compared to quasistatic response of the panel tested using an hemispherical indenter.

  17. A comparative study of the impact properties of sandwich materials with different cores

    Science.gov (United States)

    Ramakrishnan, K. R.; Shankar, K.; Viot, P.; Guerard, S.

    2012-08-01

    Sandwich panels are made of two high strength skins bonded to either side of a light weight core and are used in applications where high stiffness combined with low structural weight is required. The purpose of this paper is to compare the mechanical response of several sandwich panels whose core materials are different. Sandwich panels with glass fibre-reinforced polymer face sheets were used, combined with five different cores; polystyrene foam, polypropylene honeycomb, two different density Balsa wood and Cork. All specimens were subjected to low velocity impact and their structural response (Force-displacement curves) were compared to quasistatic response of the panel tested using an hemispherical indenter.

  18. Comparative dissolution study of drug and inert isomalt based core material from layered pellets.

    Science.gov (United States)

    Kállai-Szabó, Nikolett; Luhn, Oliver; Bernard, Joerg; Kállai-Szabó, Barnabás; Zelkó, Romána; Antal, István

    2014-09-01

    Layered and coated pellets were formulated to control the release of the diclofenac sodium selected as model drug. A highly water soluble isomalt inert pellet core material was used to osmotically modulate the drug release through the swellable polyvinyl acetate coating layer. Image analysis was applied to determine the shape parameters and the swelling behavior of the pellets. UV-spectroscopy and liquid chromatography with refractive index detection were applied to measure the concentration of the model drug and the core materials. Simultaneous dissolution of both the diclofenac sodium and isomalt was observed. Relationship was found between the dissolution profile of the drug and the core material which linear correlation was independent on the coating level. The latter enables the modulation of drug release beside the permeability control of the swelled coating polymer.

  19. Development of Sacrificial Material for the Eu-APR1400 Core Catcher

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Jung Soo; Kim, Mun Soo; Kim, Yong Soo [KHNP Central Research Institute, Daejeon (Korea, Republic of)

    2011-10-15

    To increase and diversify the export marker of the Korean nuclear reactor design, we developed the Eu- APR1400 reactor design based on the APR1400 reactor design, satisfying the European nuclear design requirements including the European Utility Requirements (EUR) and the Finnish requirements of YVL. As recommended by both requirements, the so called core-catcher molten core ex-vessel cooling facility was developed to manage a severe accident at the Eu-APR1400 reactor involving a core meltdown and to mitigate its consequences. Usually, sacrificial material (SM), which controls the melt properties and modifies melt conditions favorable to corium retention, can be employed to protect the core catcher body from the molten core and increase its cooling capability. The EPR reactor design (by Areva, France) core catcher consists of the initial corium retention space, the transportation channel and the wide spreading room for core melt cooling. The EPR used two kinds of SM to protect the initial core retention space from core melt and to spread the core melt across the wide spreading room using the different compositions. The VVER (Russia) ensures melt localization in a water-cooled vessel located directly beneath the reactor. SM is used to remove the thermal focusing effect by the layer inversion process between metallic and oxidic melts. The functional requirements for the SM determined for the present core catcher are (1) melting spreading improvement, (2) focusing effect prevention, (3) hydrogen explosion prevention, (4) FP (fission product) release decreasing, and (5) melt recriticality exclusion. The rest of the paper is organized as follows. The next section provides detailed descriptions of the composition of the present SM, which satisfies its functional requirements. Following this, the manufacturing process of the SM is presented

  20. LMFBR type reactor core and its fuel exchange method

    Energy Technology Data Exchange (ETDEWEB)

    Ishibashi, Yoko; Koyama, Jun-ichi; Aoyama, Motoo; Haikawa, Katsumasa; Yamanaka, Akihiro

    1996-08-20

    Upon initial loading, two kinds of fuel assemblies including first fuel assemblies having a highest enrichment degree and second fuel assemblies having a lowest enrichment degree are loaded. The average fuel enrichment degree of an upper region of the first fuel assembly is made greater than that of the lower region. The reactivity of the lower region of the first fuel assembly is made lower than that of the upper portion to reduce power peak. Upon transfer from a first cycle to a second cycle, at least one of the second fuel assemblies is exchanged by the same number of the third fuel assemblies. In this case, an average fuel enrichment degree of the upper region of the third fuel assembly is made greater than that of the lower region to suppress the reactivity in the lower region of the third fuel assembly lower than the reactivity in the upper region thereby reducing the power peak. Thus, the upper power peak over the entire reactor core is moderated thereby capable of ensuring the reactor shut down margin without deteriorating the same. (N.H.)

  1. Core-collapse and Type Ia supernovae with the SKA

    CERN Document Server

    Pérez-Torres, M A; Beswick, R J; Lundqvist, P; Herrero-Illana, R; Romero-Cañizales, C; Ryder, S; della Valle, M; Conway, J; Marcaide, J M; Mattila, S; Murphy, T; Ros, E

    2014-01-01

    Core-collapse SNe (CCSNe): Systematic searches of radio emission from CCSNe are still lacking, and only targeted searches of radio emission from just some of the optically discovered CCSNe in the local universe have been carried out. Optical searches miss a significant fraction of CCSNe due to dust obscuration; therefore, CCSN radio searches are much more promising for yielding the complete, unobscured star-formation rates in the local universe. The forthcoming SKA yields the possibility to piggyback for free in this area of research by carrying out commensal, wide-field, blind transient survey observations. SKA1-sur should be able to discover several hundreds of CCSNe in just one year, compared to about a dozen CCSNe that the VLASS would be able to detect in one year, at most. SKA, with an expected sensitivity ten times that of SKA1, is expected to detect CCSNe in the local Universe by the thousands. Therefore, commensal SKA observations could easily result in an essentially complete census of all CCSNe in t...

  2. CORE

    DEFF Research Database (Denmark)

    Krigslund, Jeppe; Hansen, Jonas; Hundebøll, Martin

    2013-01-01

    different flows. Instead of maintaining these approaches separate, we propose a protocol (CORE) that brings together these coding mechanisms. Our protocol uses random linear network coding (RLNC) for intra- session coding but allows nodes in the network to setup inter- session coding regions where flows...... intersect. Routes for unicast sessions are agnostic to other sessions and setup beforehand, CORE will then discover and exploit intersecting routes. Our approach allows the inter-session regions to leverage RLNC to compensate for losses or failures in the overhearing or transmitting process. Thus, we...... increase the benefits of XORing by exploiting the underlying RLNC structure of individual flows. This goes beyond providing additional reliability to each individual session and beyond exploiting coding opportunistically. Our numerical results show that CORE outperforms both forwarding and COPE...

  3. CORE

    DEFF Research Database (Denmark)

    Krigslund, Jeppe; Hansen, Jonas; Hundebøll, Martin

    2013-01-01

    different flows. Instead of maintaining these approaches separate, we propose a protocol (CORE) that brings together these coding mechanisms. Our protocol uses random linear network coding (RLNC) for intra- session coding but allows nodes in the network to setup inter- session coding regions where flows...... intersect. Routes for unicast sessions are agnostic to other sessions and setup beforehand, CORE will then discover and exploit intersecting routes. Our approach allows the inter-session regions to leverage RLNC to compensate for losses or failures in the overhearing or transmitting process. Thus, we...... increase the benefits of XORing by exploiting the underlying RLNC structure of individual flows. This goes beyond providing additional reliability to each individual session and beyond exploiting coding opportunistically. Our numerical results show that CORE outperforms both forwarding and COPE...

  4. Hyperbranched polymer-cored star polyfluorenes as blue light-emitting materials

    Institute of Scientific and Technical Information of China (English)

    HAN Yang; SUN MingHao; FEI ZhuPing; BO ZhiShan

    2008-01-01

    Hyperbranched polymer-cored star polyfluorenes with high molecular weights and narrow molecular weight distribution were prepared by palladium-catalyzed one-pot Suzuki polycondensation of multi-functional cores and an AB-type monomer. The optical, electrochemical and thermal properties of the hyperbranched polymer-cored star polymers were investigated. These polymers exhibited good ther-mal and color stability in solid state, and there was no significant blue-green emission after the poly-mers had been annealed in air for 2.5 h. Their three-dimensional hyperbranched structures could ef-fectively reduce the aggregation of the peripheral rigid linear conjugated polyfluorene chains.

  5. Antibacterial properties of amalgam and composite resin materials used as cores under crowns.

    Science.gov (United States)

    Al Ghadban, A; Al Shaarani, F

    2012-06-01

    The Aim of this Study was to compare the bacterial growth in the bulk of both amalgam and fluoridated composite resin materials used as cores under crowns at core's surface (in the superficial area of the bulk) and depth levels. With 24 lower premolars, 12 of them were restored with metal posts and amalgam cores (group 1). The rest were restored with glass Fiber-reinforced Composite (FRC) posts and fluoridated composite resin cores (group 2). All specimens were covered with aluminium crowns cemented with resin cement, and then they were soaked in natural saliva for three months. Excoriations abraded from the superficial and the depth areas of the core materials were cultured under aerobic conditions on blood agar plates. After incubation for 2 days, colonies formed on the plates were identified, and the CFU mg(-1) counts were recorded accordingly. Statistical analysis was performed using an independent sample T test. The mean values of CFU mg(-1) counts in group 2 excoriations (surface 39.75, and depth 9.75) were higher than the group 1 excoriations (surface 1.67, and depth 0.42). This study supports the use of amalgam for building up cores due to its antibacterial properties. Composite resin, however, enhanced sizable bacterial growth despite the presence of fluoride.

  6. Influence of different post core materials on the color of Empress 2 full ceramic crowns

    Institute of Scientific and Technical Information of China (English)

    GE Jing; WANG Xin-zhi; FENG Hai-lan

    2006-01-01

    Background For esthetic consideration, dentin color post core materials were normally used for all-ceramic crown restorations. However, in some cases, clinicians have to consider combining a full ceramic crown with a metal post core. Therefore, this experiment was conducted to test the esthetical possibility of applying cast metal post core in a full ceramic crown restoration.Methods The color of full ceramic crowns on gold and Nickel-Chrome post cores was compared with the color of the same crowns on tooth colored post cores. Different try-in pastes were used to imitate the influence of a composite cementation on the color of different restorative combinations. The majority of patients could not detect any color difference less than △E 1.8 between the two ceramic samples. So, △E 1.8 was taken as the objective evaluative criterion for the evaluation of color matching and patients' satisfaction.Results When the Empress 2 crown was combined with the gold alloy post core, the color of the resulting material was similar to that of a glass fiber reinforced resin post core (△E = 0.3). The gold alloy post core and the try-in paste did not show a perceptible color change in the full ceramic crowns, which indicated that the color of the crowns might not be susceptible to change between lab and clinic as well as during the process of composite cementation. Without an opaque covering the Ni-Cr post core would cause an unacceptable color effect on the crown (△E = 2.0), but with opaque covering, the color effect became more clinically satisfactory (△E=1.8).Conclusions It may be possible to apply a gold alloy post core in the Empress 2 full ceramic crown restoration when necessary. If a non-extractible Ni-Cr post core exists in the root canal, it might be possible to restore the tooth with an Empress 2 crown after coveting the labial surface of the core with one layer of opaque resin cement.

  7. Nanocrystalline material in toroidal cores for current transformer: analytical study and computational simulations

    Directory of Open Access Journals (Sweden)

    Benedito Antonio Luciano

    2005-12-01

    Full Text Available Based on electrical and magnetic properties, such as saturation magnetization, initial permeability, and coercivity, in this work are presented some considerations about the possibilities of applications of nanocrystalline alloys in toroidal cores for current transformers. It is discussed how the magnetic characteristics of the core material affect the performance of the current transformer. From the magnetic characterization and the computational simulations, using the finite element method (FEM, it has been verified that, at the typical CT operation value of flux density, the nanocrystalline alloys properties reinforce the hypothesis that the use of these materials in measurement CT cores can reduce the ratio and phase errors and can also improve its accuracy class.

  8. Controllable core-shell-type resin for solid-phase peptide synthesis.

    Science.gov (United States)

    Cho, Hong-Jun; Lee, Tae-Kyung; Kim, Jung Won; Lee, Sang-Myung; Lee, Yoon-Sik

    2012-10-19

    A simple, mild, and inexpensive biphasic functionalization approach is attempted for preparing an ideal core-shell-type resin. The core-shell-type architecture was constructed by coupling Fmoc-OSu to the amino groups on the shell layer of an aminomethyl polystyrene (AM PS) resin. The shell layer thickness of the resin could be easily controlled under mild conditions, which was characterized by confocal laser scanning microscopy (CLSM). The efficiency of core-shell-type resin for solid-phase peptide synthesis (SPPS) was demonstrated by the synthesis of various peptides and compared with commercially available noncore-shell-type resins such as AM PS and poly(ethylene glycol)-based resins. The core-shell-type resin provided effective performance during the synthesis of hydrophobic peptide sequences, a disulfide-bridged cyclic peptide, and a difficult PNA sequence. Furthermore, a highly aggregative peptide fragment, MoPrP 105-125, was synthesized more efficiently on the core-shell-type resin under microwave conditions than AM PS and ChemMatrix resins.

  9. [Influence of background color on chromatic value of four all-ceramic system core materials].

    Science.gov (United States)

    Ma, Yong-gang; Zhang, Nian; Deng, Xu-liang

    2010-06-01

    To investigate the influence of post-core background color on chromatic value of four all-ceramic system core materials at clinically appropriate thicknesses. Disc specimens of 15 mm in diameter and 0.80 mm in thickness (Empress II: Group A), and 0.50 mm in thickness (In-Ceram Zirconia core: Group B; Cercon base color zirconia core: Group C; Cercon base zirconia core: Group D) were fabricated, five in each group. Au-Pt alloy, Ni-Cr alloy and visible light cured dental composite resin (A2 color) background were prepared. Samples were put on different background and their chromatic values were measured with colorimeter (CIE-1976-L(*)a(*)b(*)). Color differences of each specimen on different background material were calculated. The color differences among specimens of Group A on different background material were more than 1.5 (2.83 ± 0.70) which meant it could be noticeable to eyes. Those of zirconia were less than 1.5 [Group B: (0.14 ± 0.08); Group C: (0.90 ± 0.20); Group D: (0.99 ± 0.09)]. The influence of background color on Group A was noticeable to human eyes, and as a result, tooth-colored post should be used for this all-ceramic system. For the other three kinds of zirconia core materia1 system, the color differences among specimens on different background material were unnoticeable. Therefore the three all-ceramic systems have excellent color masking ability and can be used on all color background.

  10. Experimental validation of the Higher-Order Theory approach for sandwich panels with flexible core materials

    NARCIS (Netherlands)

    Straalen, IJ.J. van

    2000-01-01

    During tthe 1990's the higher-order theory was developed by Frostig to enable detailed stress analyses of sandwich panel structures. To investigate the potentials of this approach experiments are performed on sandwich panels made of thin steel faces and mineral wool or polystyrene core material. A p

  11. Simulant-material experimental investigation of flow dynamics in the CRBR Upper-Core Structure

    Energy Technology Data Exchange (ETDEWEB)

    Wilhelm, D.; Starkovich, V.S.; Chapyak, E.J.

    1982-09-01

    The results of a simulant-material experimental investigation of flow dynamics in the Clinch River Breeder Reactor (CRBR) Upper Core Structure are described. The methodology used to design the experimental apparatus and select test conditions is detailed. Numerous comparisons between experimental data and SIMMER-II Code calculations are presented with both advantages and limitations of the SIMMER modeling features identified.

  12. Toolkit for Evaluating Alignment of Instructional and Assessment Materials to the Common Core State Standards

    Science.gov (United States)

    Achieve, Inc., 2014

    2014-01-01

    In joint partnership, Achieve, The Council of Chief State School Officers, and Student Achievement Partners have developed a Toolkit for Evaluating the Alignment of Instructional and Assessment Materials to the Common Core State Standards. The Toolkit is a set of interrelated, freely available instruments for evaluating alignment to the CCSS; each…

  13. Analysis of the Flexure Behavior and Compressive Strength of Fly Ash Core Sandwiched Composite Material

    Directory of Open Access Journals (Sweden)

    Vijaykumar H.K

    2014-07-01

    Full Text Available In this paper, commercially available Fly Ash and Epoxy is used for the core material, woven glass fabric as reinforcing skin material, epoxy as matrix/adhesive materials used in this study for the construction of sandwich composite. Analysis is carried out on different proportions of epoxy and fly ash sandwiched composite material for determining the flexural strength and compressive strength, three different proportions of epoxy and fly ash used for the study. Those are 65%-35% (65% by weight fly ash and 35% by weight epoxy resin composite material, 60%-40% and 55%-45% composite material. 60%-40% composite material specimen shows better results in the entire test carried out i.e. Flexure and Compression. The complete experimental results are discussed and presented in this paper.

  14. Innovative use of wood-plastic-composites (WPC) as a core material in the sandwich injection molding process

    Science.gov (United States)

    Moritzer, Elmar; Martin, Yannick

    2016-03-01

    The demand for materials based on renewable raw materials has risen steadily in recent years. With society's increasing interest for climate protection and sustainability, natural-based materials such as wood-plastic-composites (WPC) have gained market share thanks to their positive reputation. Due to advantages over unreinforced plastics such as cost reduction and weight savings it is possible to use WPC in a wide area of application. Additionally, an increase in mechanical properties such as rigidity and strength is achieved by the fibers compared to unreinforced polymers. The combination of plastic and wood combines the positive properties of both components in an innovative material. Despite the many positive properties of wood-plastic-composite, there are also negative characteristics that prevent the use of WPC in many product areas, such as automotive interiors. In particular, increased water intake, which may result in swelling of near-surface particles, increased odor emissions, poor surface textures and distortion of the components are unacceptable for many applications. The sandwich injection molding process can improve this situation by eliminating the negative properties of WPC by enclosing it with a pure polymer. In this case, a layered structure of skin and core material is produced, wherein the core component is completely enclosed by the skin component. The suitability of WPC as the core component in the sandwich injection molding has not yet been investigated. In this study the possibilities and limitations of the use of WPC are presented. The consideration of different fiber types, fiber contents, skin materials and its effect on the filling behavior are the focus of the presented analysis.

  15. Thermal analysis of HTS air-core transformer used in voltage compensation type active SFCL

    Science.gov (United States)

    Song, M.; Tang, Y.; Li, J.; Zhou, Y.; Chen, L.; Ren, L.

    2010-11-01

    The three-phase voltage compensation type active superconducting fault current limiter (SFCL) is composed of three HTS air-core transformers and a three-phase four-wire Pulse Width Modulation (PWM) converter. The primary winding of the each phase HTS air-core transformer is in series with the main system, and the second winding is connected with the PWM converter. The single-phase conduction-cooled HTS air-core transformer is consisting of four double-pancakes wound by the Bi2223/Ag tape. In this paper, according to the electromagnetic analysis on the single-phase HTS air-core transformer, its AC loss corresponding to different operation modes is calculated. Furthermore, the thermal behaviors are studied by the time-stepping numerical simulations. On the basis of the simulation results, the related problems with the HTS air-core transformer's thermal stability are discussed.

  16. Colloidal crystals of core-shell type spheres with poly(styrene) core and poly(ethylene oxide) shell.

    Science.gov (United States)

    Okamoto, Junichi; Kimura, Hiroshi; Tsuchida, Akira; Okubo, Tsuneo; Ito, Koichi

    2007-04-15

    Elastic modulus and crystal growth kinetics have been studied for colloidal crystals of core-shell type colloidal spheres (diameter=160-200 nm) in aqueous suspension. Crystallization properties of three kinds of spheres, which have poly(styrene) core and poly(ethylene oxide) shell with different oxyethylene chain length (n=50, 80 and 150), were examined by reflection spectroscopy. The suspensions were deionized exhaustively for more than 1 year using mixed bed of ion-exchange resins. The rigidities of the crystals range from 0.11 to 120 Pa and from 0.56 to 76 Pa for the spheres of n=50 and 80, respectively, and increase sharply as the sphere volume fraction increase. The g factor, parameter for crystal stability, range from 0.029 to 0.13 and from 0.040 to 0.11 for the spheres of n=50 and 80, respectively. These g values indicate the formation of stable crystals, and the values were decreased as the sphere volume fraction increased. Two components of crystal growth rate coefficients, fast and slow, were observed in the order from 10(-3) to 10(1)s(-1). This is due to the secondary process in the colloidal crystallization mechanism, corresponding to reorientation from metastable crystals formed in the primary process and/or Ostwald-ripening process. There are no distinct differences in the structural, kinetic and elastic properties among the colloidal crystals of the different core-shell size spheres, nor difference between those of core-shell spheres and silica or poly(styrene) spheres. The results are very reasonably interpreted by the fact that colloidal crystals are formed in a closed container owing to long-range repulsive forces and the Brownian movement of colloidal spheres surrounded by extended electrical double layers, and their formation is not influenced by the rigidity and internal structure of the spheres.

  17. The Processing Technology of the Core Dam Material of the High Gravel Soil Core Wall Dam%高砾石土心墙坝心墙料加工技术

    Institute of Scientific and Technical Information of China (English)

    屈庆余

    2011-01-01

    砾石土心墙堆石坝已逐渐成为世界高坝建设的主流坝型之一,砾石土心墙料加工是大坝施工的关键环节之一。从砾石土的筛分、级配骨料的加工、心墙料的掺合三个环节介绍了高砾石土心墙坝心墙料加工技术.对于高砾石土心墙坝施工具有指导意义。%The gravel soil core wall rock fill dam has become one of the mainstream dam types in high dam construction around the world and the gravel soil core wall material processing is one of the keys in dam construction. This paper introduces the processing technology of the core wall material high gravel soil core wall dam from the three process of the screening of gravel soil, the processing of graded aggregate and the blending of core wall material, which has a good practical and guiding significance to the construction of high gravel soil core wall dam.

  18. Rare-Earth-Free Permanent Magnets for Electrical Vehicle Motors and Wind Turbine Generators: Hexagonal Symmetry Based Materials Systems Mn-Bi and M-type Hexaferrite

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Yang-Ki [University of Alabama; Haskew, Timothy [University of Alabama; Myryasov, Oleg [University of Alabama; Jin, Sungho [University of California San Diego; Berkowitz, Ami [University of California San Diego

    2014-06-05

    The research we conducted focuses on the rare-earth (RE)-free permanent magnet by modeling, simulating, and synthesizing exchange coupled two-phase (hard/soft) RE-free core-shell nano-structured magnet. The RE-free magnets are made of magnetically hard core materials (high anisotropy materials including Mn-Bi-X and M-type hexaferrite) coated by soft shell materials (high magnetization materials including Fe-Co or Co). Therefore, our research helps understand the exchange coupling conditions of the core/shell magnets, interface exchange behavior between core and shell materials, formation mechanism of core/shell structures, stability conditions of core and shell materials, etc.

  19. 9 CFR 354.247 - Table showing types of materials.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Table showing types of materials. 354... Sanitary Conditions and Precautions Against Contamination of Products § 354.247 Table showing types of materials. Equipment, utensils, and facilities Iron Stainless steel and monel metal Aluminum Galvanized...

  20. Determination of electrical properties of materials used in microwaveheating of foundry moulds and cores

    Directory of Open Access Journals (Sweden)

    B. Opyd

    2015-04-01

    Full Text Available The environment-friendly and cost efficient microwave heating of moulding and core sands opens possibilities to use plastics and wood for structures of foundry instrumentation, where transparency to microwaves is the main requirement. Presented are results of a preliminary research on determining possibilities to use selected materials in microwave field. From the viewpoint of specificity of this process, the basic parameter is ability to absorb or transmit microwave radiation. Determined were the following electrical properties: tangent of dielectric loss angle and permittivity of selected materials. The materials were classified according to their transparency to electromagnetic radiation in order to choose the ones suitable for tooling applied in foundry processes.

  1. The core-degenerate scenario for the progenitors of Type Ia supernovae

    Science.gov (United States)

    Wang, B.; Zhou, W.-H.; Zuo, Z.-Y.; Li, Y.-B.; Luo, X.; Zhang, J.-J.; Liu, D.-D.; Wu, C.-Y.

    2017-02-01

    The origin of the progenitors of Type Ia supernovae (SNe Ia) is still uncertain. The core-degenerate (CD) scenario has been proposed as an alternative way for the production of SNe Ia. In this scenario, SNe Ia are formed at the final stage of common-envelope evolution from a merger of a carbon-oxygen white dwarf (CO WD) with the CO core of an asymptotic giant branch companion. However, the birthrates of SNe Ia from this scenario are still not well determined. In this work, we performed a detailed investigation on the CD scenario based on a binary population synthesis approach. The SN Ia delay times from this scenario are basically in the range of 90-2500 Myr, mainly contributing to the observed SNe Ia with short and intermediate delay times, although this scenario can also produce some old SNe Ia. Meanwhile, our work indicates that the Galactic birthrates of SNe Ia from this scenario are not more than 20 per cent of total SNe Ia due to more careful treatment of mass transfer. Although the SN Ia birthrates in this work are lower than those in Ilkov & Soker, the CD scenario cannot be ruled out as a viable mechanism for the formation of SNe Ia. Especially, SNe Ia with circumstellar material from this scenario contribute to 0.7-10 per cent of total SNe Ia, which means that the CD scenario can reproduce the observed birthrates of SNe Ia like PTF 11kx. We also found that SNe Ia happen systemically earlier for a high value of metallicity and their birthrates increase with metallicity.

  2. Physical properties of self-, dual-, and light-cured direct core materials.

    Science.gov (United States)

    Rüttermann, Stefan; Alberts, Ian; Raab, Wolfgang H M; Janda, Ralf R

    2011-08-01

    The objective of this study is to evaluate flexural strength, flexural modulus, compressive strength, curing temperature, curing depth, volumetric shrinkage, water sorption, and hygroscopic expansion of two self-, three dual-, and three light-curing resin-based core materials. Flexural strength and water sorption were measured according to ISO 4049, flexural modulus, compressive strength, curing temperature, and curing depth according to well-proven, literature-known methods, and the volumetric behavior was determined by the Archimedes' principle. ANOVA was calculated to find differences between the materials' properties, and correlation of water sorption and hygroscopic expansion was analysed according to Pearson (p < 0.05). Clearfil Photo Core demonstrated the highest flexural strength (125 ± 12 MPa) and curing depth (15.2 ± 0.1 mm) and had the highest flexural modulus (≈12.6 ± 1.2 GPa) concertedly with Multicore HB. The best compressive strength was measured for Voco Rebilda SC and Clearfil DC Core Auto (≈260 ± 10 MPa). Encore SuperCure Contrast had the lowest water sorption (11.8 ± 3.3 µg mm(-3)) and hygroscopic expansion (0.0 ± 0.2 vol.%). Clearfil Photo Core and Encore SuperCure Contrast demonstrated the lowest shrinkage (≈2.1 ± 0.1 vol.%). Water sorption and hygroscopic expansion had a very strong positive correlation. The investigated core materials significantly differed in the tested properties. The performance of the materials depended on their formulation, as well as on the respective curing process.

  3. Recent progress on metal core@semiconductor shell nanocomposites as a promising type of photocatalyst

    Science.gov (United States)

    Zhang, Nan; Liu, Siqi; Xu, Yi-Jun

    2012-03-01

    The creation of core-shell nanocomposites (CSNs) has attracted considerable attention and developed into an increasingly important research area at the frontier of advanced materials chemistry. CSNs, which are nanoscaled assemblies with a chemical composition that is different on the surface compared to the core region, have found versatile applications in many fields, such as electrooptics, quantum dots, microscopy labels, drug delivery, chemical sensors, nanoreactors and catalysis. This review is primarily focused on the applications of metal core@semiconductor shell nanocomposites in heterogeneous photocatalysis, including photocatalytic nonselective processes for environmental remediation, selective organic transformations to fine chemicals and water splitting to clean hydrogen energy. It is hoped that this minireview can inspire multidisciplinary research interest in the precisely morphology-controlled synthesis of a variety of metal core@semiconductor shell nanoassemblies and their wide applications in the realm of heterogeneous photocatalysis.

  4. Mechanical properties of chemically bonded sand core materials dipped in sol-gel coating impregnated with filter

    DEFF Research Database (Denmark)

    Nwaogu, Ugochukwu Chibuzoh; Tiedje, Niels Skat

    2012-01-01

    -displacement curve from which the mechanical properties of the materials are deduced. The fracture surfaces were examined using a stereomicroscope and a scanning electron microscope. From the results, the strengths of the core materials were slightly reduced by the coating in tensile and flexural modes, while...... the strengths were increased under compression. The mode of fracture of the chemically bonded sand core materials was observed to be intergranular through the binder. The stiffness of the chemically bonded sand core materials was determined. For better understanding of the mechanical properties......A novel sol-gel coating impregnated with filter dust was applied on chemically bonded sand core materials by dipping. After curing, the strengths of the core materials were measured under uniaxial loading using a new strength testing machine (STM). The STM presents the loading history as a force...

  5. The effect of various base/core materials on the setting of a polyvinyl siloxane impression material.

    Science.gov (United States)

    Moon, M G; Jarrett, T A; Morlen, R A; Fallo, G J

    1996-12-01

    Five resin-modified glass ionomers and amalgam, used as a base or core buildup material, were clinically evaluated for whether they effected polymerization of a low viscosity (light body) regular set polyvinyl siloxane impression material. A total of 20 samples per group was prepared according to the manufacturer's recommendations. Ten samples from each group were handled with latex gloves during mixing and the other 10 were handled with vinyl gloves. Five of the 10 samples had the outer surface prepared with a round diamond wheel. Impressions were made of all the samples. The impression materials were visually scored inhibited or noninhibited. Inhibited impression materials met at least one following criterion: (1) an oily substance on the surface of the impression readily collected on a sterile explorer tine as it was moved across the impression surface; (2) a rippled appearance on the surface of the impression material; or (3) unpolymerized impression material adherent to the prepared sample surface. If none of the criteria were observed, the impression was scored noninhibited. The data were analyzed with the chi square analysis (level of significance p = 0.05). Total chi square analysis revealed a significant difference between brands (p = 0.0001) and between prepared and non-prepared samples (p = 0.001). Interrater reliability data were analyzed with the kappa correlation analysis. Raters were in complete agreement (kappa = +1). The prepared samples of Vitrebond material had an inhibitory effect on the polymerization of Express impression material.

  6. Guiding and amplification properties of rod-type photonic crystal fibers with sectioned core doping

    DEFF Research Database (Denmark)

    Selleri, Stefano; Poli, Federica; Passaro, Davide

    2009-01-01

    been applied to properly design the low refractive index ring in the fiber core, which can provide an increase of the differential overlap between the fundamental and the higher-order mode. Then, the gain competition among the guided modes along the Yb-doped rod-type fibers has been investigated...... with a spatial and spectral amplifier model. Simulation results have shown the effectiveness of the sectioned core doping in worsening the higher-order mode overlap on the doped area, thus providing an effective single-mode behavior of the Yb-doped rod-type photonic crystal fibers....

  7. The Common Core State Standards and the Role of Instructional Materials: A Case Study on EdReports.org

    Science.gov (United States)

    Watt, Michael G.

    2016-01-01

    The purpose of this study was to review research studies investigating the role of instructional materials in relation to the Common Core State Standards and to evaluate whether a new organisation, EdReports.org, founded to evaluate the alignment of instructional materials to the Common Core State Standards, has achieved its objectives. Content…

  8. Severe accident modeling of a PWR core with different cladding materials

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, S. C. [Westinghouse Electric Company LLC, 5801 Bluff Road, Columbia, SC 29209 (United States); Henry, R. E.; Paik, C. Y. [Fauske and Associates, Inc., 16W070 83rd Street, Burr Ridge, IL 60527 (United States)

    2012-07-01

    The MAAP v.4 software has been used to model two severe accident scenarios in nuclear power reactors with three different materials as fuel cladding. The TMI-2 severe accident was modeled with Zircaloy-2 and SiC as clad material and a SBO accident in a Zion-like, 4-loop, Westinghouse PWR was modeled with Zircaloy-2, SiC, and 304 stainless steel as clad material. TMI-2 modeling results indicate that lower peak core temperatures, less H 2 (g) produced, and a smaller mass of molten material would result if SiC was substituted for Zircaloy-2 as cladding. SBO modeling results indicate that the calculated time to RCS rupture would increase by approximately 20 minutes if SiC was substituted for Zircaloy-2. Additionally, when an extended SBO accident (RCS creep rupture failure disabled) was modeled, significantly lower peak core temperatures, less H 2 (g) produced, and a smaller mass of molten material would be generated by substituting SiC for Zircaloy-2 or stainless steel cladding. Because the rate of SiC oxidation reaction with elevated temperature H{sub 2}O (g) was set to 0 for this work, these results should be considered preliminary. However, the benefits of SiC as a more accident tolerant clad material have been shown and additional investigation of SiC as an LWR core material are warranted, specifically investigations of the oxidation kinetics of SiC in H{sub 2}O (g) over the range of temperatures and pressures relevant to severe accidents in LWR 's. (authors)

  9. Study of a core-shell type impact modifier by inverse gas chromatography.

    Science.gov (United States)

    Santos, J M R C A; Guthrie, J T

    2005-04-08

    Inverse gas chromatography (IGC) has been used to study the Lewis acid-base properties of a technologically and commercially important core-shell type elastomer (MBS rubber). The parameters determined were the dispersive component of the surface tension, the surface free energy, the enthalpy and the entropy of adsorption of polar and apolar probes, the surface Lewis acidity constant (Ka), and the surface Lewis basicity constant (Kb). The results show that the MBS rubber is amphoteric but strongly Lewis basic. It is weakly Lewis acidic. The results are in accord with the analysis of the molecular structure of PMMA, the shell component of this impact modifier (IM). The interactivity of this elastomer with the remaining materials in multicomponent polymeric systems is expected to be strongly influenced by the particular surface energetic properties of the MBS rubber. The results presented would contribute to the interpretation, forecast and optimization of the adhesion properties and phase preferences shown by this impact modifier when incorporated in such complex polymeric systems as polymer blends and composites.

  10. Highly efficient photocatalytic performance of graphene-ZnO quasi-shell-core composite material.

    Science.gov (United States)

    Bu, Yuyu; Chen, Zhuoyuan; Li, Weibing; Hou, Baorong

    2013-12-11

    In the present paper, the graphene-ZnO composite with quasi-shell-core structure was successfully prepared using a one-step wet chemical method. The photocatalytic Rhodamine B degradation property and the photoelectrochemical performance of the graphene-ZnO quasi-shell-core composite are dependent on the amount of graphene oxide that is added. When the amount of graphene oxide added is 10 mg, the graphene-ZnO quasi-shell-core composite possesses the optimal photocatalytic degradation efficiency and the best photoelectrochemical performance. An efficient interfacial electric field is established on the interface between the graphene and ZnO, which significantly improves the separation efficiency of the photogenerated electron-hole pairs and thus dramatically increases its photoelectrochemical performance. In addition to the excellent photocatalytic and photoelectrochemical properties, the electron migration ability of the grephene-ZnO quasi-shell-core composite is significantly enhanced due to the graphene coating on ZnO surface; therefore, this material has great potential for application as a substrate material to accept electrons in dye solar cell and in narrow bandgap semiconductor quantum dot sensitized solar cells.

  11. Synthesis of tetrahedral quasi-type-II CdSe-CdS core-shell quantum dots.

    Science.gov (United States)

    Sugunan, Abhilash; Zhao, Yichen; Mitra, Somak; Dong, Lin; Li, Shanghua; Popov, Sergei; Marcinkevicius, Saulius; Toprak, Muhammet S; Muhammed, Mamoun

    2011-10-21

    Synthesis of colloidal nanocrystals of II-VI semiconductor materials has been refined in recent decades and their size dependent optoelectronic properties have been well established. Here we report a facile synthesis of CdSe-CdS core-shell heterostructures using a two-step hot injection process. Red-shifts in absorption and photoluminescence spectra show that the obtained quantum dots have quasi-type-II alignment of energy levels. The obtained nanocrystals have a heterostructure with a large and highly faceted tetrahedral CdS shell grown epitaxially over a spherical CdSe core. The obtained morphology as well as high resolution electron microscopy confirms that the tetrahedral shell have a zinc blende crystal structure. A phenomenological mechanism for the growth and morphology of the nanocrystals is discussed.

  12. Luminescent liquid crystalline materials based on palladium(II) imine derivatives containing the 2-phenylpyridine core.

    Science.gov (United States)

    Micutz, Marin; Iliş, Monica; Staicu, Teodora; Dumitraşcu, Florea; Pasuk, Iuliana; Molard, Yann; Roisnel, Thierry; Cîrcu, Viorel

    2014-01-21

    In this work we report our studies concerning the synthesis and characterisation of a series of imine derivatives that incorporate the 2-phenylpyridine (2-ppy) core. These derivatives were used in the cyclometalating reactions of platinum(II) or palladium(II) in order to prepare several complexes with liquid crystalline properties. Depending on the starting materials used as well as the solvents employed, different metal complexes were obtained, some of them showing both liquid crystalline behaviour and luminescence properties at room temperature. It was found that, even if there are two competing coordination sites, the cyclometalation process takes place always at the 2-ppy core with (for Pt) or without (for Pd) the imine bond cleavage. We successfully showed that it is possible to prepare emissive room temperature liquid crystalline materials based on double cyclopalladated heteroleptic complexes by varying the volume fraction of the long flexible alkyl tails on the ancillary benzoylthiourea (BTU) ligands.

  13. Mechanism study of hollow-core fiber infrared-supercontinuum compression with bulk material

    OpenAIRE

    2010-01-01

    International audience; We numerically investigate the pulse compression mechanism in the infrared spectral range based on the successive action of nonlinear pulse propagation in a hollow-core fiber (HCF) followed by linear propagation through bulk material. We found an excellent agreement of simulated pulse properties with experimental results at 1.8 µm in the two optical-cycle regime close to the Fourier limit (FL). In particular, the spectral phase asymmetry attributable to self-steepening ...

  14. Fracture resistance of endodontically treated teeth restored with Zirconia filler containing composite core material and fiber posts

    Science.gov (United States)

    Jeaidi, Zaid Al

    2016-01-01

    Objectives: To assess the fracture resistance of endodontically treated teeth with a novel Zirconia (Zr) nano-particle filler containing bulk fill resin composite. Methods: Forty-five freshly extracted maxillary central incisors were endodontically treated using conventional step back preparation and warm lateral condensation filling. Post space preparation was performed using drills compatible for fiber posts (Rely X Fiber Post) on all teeth (n=45), and posts were cemented using self etch resin cement (Rely X Unicem). Samples were equally divided into three groups (n=15) based on the type of core materials, ZirconCore (ZC) MulticCore Flow (MC) and Luxacore Dual (LC). All specimens were mounted in acrylic resin and loads were applied (Universal testing machine) at 130° to the long axis of teeth, at a crosshead speed of 0.5 mm/min until failure. The loads and the site at which the failures occurred were recorded. Data obtained was tabulated and analyzed using a statistical program. The means and standard deviations were compared using ANOVA and Multiple comparisons test. Results: The lowest and highest failure loads were shown by groups LC (18.741±3.02) and MC (25.16±3.30) respectively. Group LC (18.741±3.02) showed significantly lower failure loads compared to groups ZC (23.02±4.21) and MC (25.16±3.30) (pcomposite cores was comparable to teeth restored with conventional Zr free bulk fill composites. Zr filled bulk fill composites are recommended for restoration of endodontically treated teeth as they show comparable fracture resistance to conventional composite materials with less catastrophic failures. PMID:28083048

  15. Optimized core design and fuel management of a pebble-bed type nuclear reactor

    NARCIS (Netherlands)

    Boer, B.

    2009-01-01

    The core design of a pebble-bed type Very High Temperature Reactor (VHTR) is optimized, aiming for an increase of the coolant outlet temperature to 1000 C, while retaining its inherent safety features. The VHTR has been selected by the international Generation IV research initiative as one of the si

  16. In-core materials testing under LWR conditions in the Halden reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, P.J.; Hauso, E.; Hoegberg, N.W.; Karlsen, T.M.; McGrath, M.A. [OECD Halden Reactor Project (Norway)

    2002-07-01

    The Halden boiling water reactor (HBWR) has been in operation since 1958. It is a test reactor with a maximum power of 18 MW and is cooled and moderated by boiling heavy water, with a normal operating temperature of 230 C and a pressure of 34 bar. In the past 15 years increasing emphasis has been placed on materials testing, both of in-core structural materials and fuel claddings. These tests require representative light water reactor (LWR) conditions, which are achieved by housing the test rigs in pressure flasks that are positioned in fuel channels in the reactor and connected to dedicated water loops, in which boiling water reactor (BWR) or pressurised water reactor (PWR) conditions are simulated. Understanding of the in-core behaviour of fuel or reactor materials can be greatly improved by on-line measurements during power operation. The Halden Project has performed in-pile measurements for a period of over 35 years, beginning with fuel temperature measurements using thermocouples and use of differential transformers for measurement of fuel pellet or cladding dimensional changes and internal rod pressure. Experience gained over this period has been applied to on-line instrumentation for use in materials tests. This paper gives details of the systems used at Halden for materials testing under LWR conditions. The techniques used to provide on-line data are described and illustrative results are presented. (authors)

  17. Electronic properties of [core+exo]-type gold clusters: factors affecting the unique optical transitions.

    Science.gov (United States)

    Shichibu, Yukatsu; Konishi, Katsuaki

    2013-06-03

    Unusual visible absorption properties of [core+exo]-type Au6 (1), Au8 (2), and Au11 (3) clusters were studied from experimental and theoretical aspects, based on previously determined crystal structures. Unlike conventional core-only clusters having no exo gold atoms, these nonspherical clusters all showed an isolated visible absorption band in solution. Density functional theory (DFT) studies on corresponding nonphenyl models (1'-3') revealed that they had similar electronic structures with discrete highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) bands. The theoretical spectra generated by time-dependent DFT (TD-DFT) calculations agreed well with the experimentally measured properties of 1-3, allowing assignment of the characteristic visible bands to HOMO-LUMO transitions. The calculated HOMO-LUMO transition energies increased in the order Au11 exo gold atom, with the HOMO → LUMO transition occurring in the core → exo direction. The HOMO/LUMO distribution patterns of 1' and 3' were similar to each other but were markedly different from that of 2', which has longer core-to-exo distances. These findings showed that not only nuclearity (size) but also geometric structures have profound effects on electronic properties and optical transitions of the [core+exo]-type clusters.

  18. Simulation of the Long period Core Design for WH type of KHNP

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Ji-Eun; Moon, Sang-Rae [Korea Hydro and Nuclear Power Co., Daejeon (Korea, Republic of)

    2016-10-15

    The current core design of the reactor and the new design of long period based on ANC code are compared here targeting the unit of WH type(Westinghouse nuclear steam supply system) operated by KHNP. The reactor core is composed of 157 fuel assemblies, consisting of a 17×17 array with 264 fuel rods, 24 guide thimbles. To investigate susceptibility of CIPS(crud-induced power shift) for long period core design, the boron mass is also calculated here. The long period core design for WH type of KHNP is simulated and evaluated the risk assessment for the result. 89 feed assemblies and 4.95w/o uranium enrichment (3.2w/o for Axial-blanket) are used for fresh fuel rods. The cycle length of long period design is increased by 6 month than the average of operated cycles satisfying the criteria of risk assessment for the core design; maximum F△h and maximum pin burnup and so on, except burndown curve.

  19. Higher-order mode suppression in rod-type photonic crystal fibers with sectioned doping and enlarged core

    DEFF Research Database (Denmark)

    Poli, F.; Coscelli, E.; Passaro, D.

    2010-01-01

    the doped-area dimension. Sectioned core doping, obtained by adding a low refractive index ring in the fiber core, has been taken into account, in order to design fibers with an effective single-mode behaviour. Moreover, the gain competition among the guided modes in the enlarged-core rod-type PCFs has been...

  20. Steady Thermal Field Simulation of Forced Air-cooled Column-type Air-core Reactor

    Institute of Scientific and Technical Information of China (English)

    DENG Qiu; LI Zhenbiao; YIN Xiaogen; YUAN Zhao

    2013-01-01

    Modeling the steady thermal field of the column-type air-core reactor,and further analyzing its distribution regularity,will help optimizing reactor design as well as improving its quality.The operation mechanism and inner insulation structure of a novel current limiting column-type air-core reactor is introduced in this paper.The finite element model of five encapsulation forced air-cooled column type air-core reactor is constructed using Fluent.Most importantly,this paper present a new method that,the steady thermal field of reactor working under forced air-cooled condition is simulated without arbitrarily defining the convection heat transfer coefficient for the initial condition; The result of the thermal field distribution shows that,the maximum steady temperature rise of forced air-cooled columntype air-core reactor happens approximately 5% to its top.The law of temperature distribution indicates:In the 1/3part of the reactor to its bottom,the temperature will rise rapidly to the increasing of height,yet the gradient rate is gradually decreasing; In the 5 % part of the reactor to its top,the temperature will drop rapidly to the increasing of height; In the part between,the temperature will rise slowly to the increasing of height.The conclusion draws that more thermal withstand capacity should be considered at the 5 % part of the reactor to its top to achieve optimal design solution.

  1. Dependences of optical properties of spherical two-layered nanoparticles on parameters of gold core and material shell

    Science.gov (United States)

    Pustovalov, V. K.; Astafyeva, L. G.; Zharov, V. P.

    2013-12-01

    Modeling of nonlinear dependences of optical properties of spherical two-layered gold core and some material shell nanoparticles (NPs) placed in water on parameters of core and shell was carried out on the basis of the extended Mie theory. Efficiency cross-sections of absorption, scattering and extinction of radiation with wavelength 532 nm by core-shell NPs in the ranges of core radii r00=5-40 nm and of relative NP radii r1/r00=1-8 were calculated (r1-radius of two-layered nanoparticle). Shell materials were used with optical indexes in the ranges of refraction n1=0.2-1.5 and absorption k1=0-3.5 for the presentation of optical properties of wide classes of shell materials (including dielectrics, metals, polymers, vapor shell around gold core). Results show nonlinear dependences of optical properties of two-layered NPs on optical indexes of shell material, core r00 and relative NP r1/r00 radii. Regions with sharp decrease and increase of absorption, scattering and extinction efficiency cross-sections with changing of core and shell parameters were investigated. These dependences should be taken into account for applications of two-layered NPs in laser nanomedicine and optical diagnostics of tissues. The results can be used for experimental investigation of shell formation on NP core and optical determination of geometrical parameters of core and shell of two-layered NPs.

  2. Preparation of Cotton-Wool-Like Poly(lactic acid-Based Composites Consisting of Core-Shell-Type Fibers

    Directory of Open Access Journals (Sweden)

    Jian Wang

    2015-11-01

    Full Text Available In previous works, we reported the fabrication of cotton-wool-like composites consisting of siloxane-doped vaterite and poly(l-lactic acid (SiVPCs. Various irregularly shaped bone voids can be filled with the composite, which effectively supplies calcium and silicate ions, enhancing the bone formation by stimulating the cells. The composites, however, were brittle and showed an initial burst release of ions. In the present work, to improve the mechanical flexibility and ion release, the composite fiber was coated with a soft, thin layer consisting of poly(d,l-lactic-co-glycolic acid (PLGA. A coaxial electrospinning technique was used to prepare a cotton-wool-like material comprising “core-shell”-type fibers with a diameter of ~12 µm. The fibers, which consisted of SiVPC coated with a ~2-µm-thick PLGA layer, were mechanically flexible; even under a uniaxial compressive load of 1.5 kPa, the cotton-wool-like material did not exhibit fracture of the fibers and, after removing the load, showed a ~60% recovery. In Tris buffer solution, the initial burst release of calcium and silicate ions from the “core-shell”-type fibers was effectively controlled, and the ions were slowly released after one day. Thus, the mechanical flexibility and ion-release behavior of the composites were drastically improved by the thin PLGA coating.

  3. Reduction of power loss in a three-phase transformer core by using Y-45° type T-joint

    Science.gov (United States)

    Basak, A.

    1980-04-01

    In a scale model of three-phase transformer cores, a novel type of T-joint configuration, referred to as the Y-45° T-joint, has been investigated. The overall power loss in this core has been found to be 9% lower than that in a core with the common 45-90° T-joint at a core flux density of 1.5 T.

  4. Analysis of ringing effects due to magnetic core materials in pulsed nuclear magnetic resonance circuits

    Energy Technology Data Exchange (ETDEWEB)

    Prabhu Gaunkar, N., E-mail: neelampg@iastate.edu; Bouda, N. R. Y.; Nlebedim, I. C.; Hadimani, R. L.; Mina, M.; Jiles, D. C. [Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa 50011 (United States); Bulu, I.; Ganesan, K.; Song, Y. Q. [Schlumberger-Doll Research, Cambridge, Massachusetts 02139 (United States)

    2015-05-07

    This work presents investigations and detailed analysis of ringing in a non-resonant pulsed nuclear magnetic resonance (NMR) circuit. Ringing is a commonly observed phenomenon in high power switching circuits. The oscillations described as ringing impede measurements in pulsed NMR systems. It is therefore desirable that those oscillations decay fast. It is often assumed that one of the causes behind ringing is the role of the magnetic core used in the antenna (acting as an inductive load). We will demonstrate that an LRC subcircuit is also set-up due to the inductive load and needs to be considered due to its parasitic effects. It is observed that the parasitics associated with the inductive load become important at certain frequencies. The output response can be related to the response of an under-damped circuit and to the magnetic core material. This research work demonstrates and discusses ways of controlling ringing by considering interrelationships between different contributing factors.

  5. Comparative Evaluation of Shear Bond Strength of Luting Cements to Different Core Buildup Materials in Lactic Acid Buffer Solution.

    Science.gov (United States)

    Patil, Siddharam M; Kamble, Vikas B; Desai, Raviraj G; Arabbi, Kashinath C; Prakash, Ved

    2015-08-01

    The core buildup material is used to restore badly broken down tooth to provide better retention for fixed restorations. The shear bond strength of a luting agent to core buildup is one of the crucial factors in the success of the cast restoration. The aim of this invitro study was to evaluate and compare the shear bond strength of luting cements with different core buildup materials in lactic acid buffer solution. Two luting cements {Traditional Glass Ionomer luting cement (GIC) and Resin Modified Glass Ionomer luting cement (RMGIC)} and five core buildup materials {Silver Amalgam, Glass ionomer (GI), Glass Ionomer Silver Reinforced (GI Silver reinforced), Composite Resin and Resin Modified Glass Ionomer(RMGIC)} were selected for this study. Total 100 specimens were prepared with 20 specimens for each core buildup material using a stainless steel split metal die. Out of these 20 specimens, 10 specimens were bonded with each luting cement. All the bonded specimens were stored at 37(0)c in a 0.01M lactic acid buffer solution at a pH of 4 for 7days. Shear bond strength was determined using a Universal Testing Machine at a cross head speed of 0.5mm/min. The peak load at fracture was recorded and shear bond strength was calculated. The data was statistically analysed using Two-way ANOVA followed by HOLM-SIDAK method for pair wise comparison at significance level of pstrength of the luting cements (pcore materials (pstrength values than Traditional GIC luting cement for all the core buildup materials. RMGIC core material showed higher bond strength values followed by Composite resin, GI silver reinforced, GI and silver amalgam core materials for both the luting agents. Shear bond strength of RMGIC luting cement was significantly higher than traditional GIC luting cement for all core buildup materials except, for silver amalgam core buildup material. RMGIC core material showed highest shear bond strength values followed by Composite resin, GI Silver Reinforced, GI and

  6. Types of architectural structures and the use of smart materials

    Science.gov (United States)

    Tavşan, Cengiz; Sipahi, Serkan

    2017-07-01

    about smart materials; the second discusses the types and characteristics of smart materials over the tables detailing their utilization and functions in the structures included in the set of examples. The final section of the study, on the other hand, elaborates on the findings, discussing them with reference to the types of structures.

  7. Exploratory study of molten core material/concrete interactions, July 1975--March 1977. [BWR; PWR

    Energy Technology Data Exchange (ETDEWEB)

    Powers, D.A.; Dahlgren, D.A.; Muir, J.F.; Murfin, W.D.

    1978-02-01

    An experimental study of the interaction between high-temperature molten materials and structural concrete is described. The experimental efforts focused on the interaction of melts of reactor core materials weighing 12 to 200 kg at temperatures 1700 to 2800/sup 0/C with calcareous and basaltic concrete representative of that found in existing light-water nuclear reactors. Observations concerning the rate and mode of melt penetration into concrete, the nature and generation rate of gases liberated during the interaction, and heat transfer from the melt to the concrete are described. Concrete erosion is shown to be primarily a melting process with little contribution from mechanical spallation. Water and carbon dioxide thermally released from the concrete are extensively reduced to hydrogen and carbon monoxide. Heat transfer from the melt to the concrete is shown to be dependent on gas generation rate and crucible geometry. Interpretation of results from the interaction experiments is supported by separate studies of the thermal decomposition of concretes, response of bulk concrete to intense heat fluxes (28 to 280 W/cm/sup 2/), and heat transfer from molten materials to decomposing solids. The experimental results are compared to assumptions made in previous analytic studies of core meltdown accidents in light-water nuclear reactors. A preliminary computer code, INTER, which models and extrapolates results of the experimental program is described. The code allows estimation of the effect of physical parameters on the nature of the melt/concrete interaction.

  8. Reliability and properties of core materials for all-ceramic dental restorations

    Directory of Open Access Journals (Sweden)

    Seiji Ban

    2008-07-01

    Full Text Available Various core materials have been used as all-ceramic dental restorations. Since many foreign zirconia product systems were introduced to the Japanese dental market in the past few years, the researches and the papers on zirconia for ceramic biomaterials have immediately drawn considerable attention. Recently, most of the manufactures supply zirconia blocks available to multi-unit posterior bridges using CAD/CAM, because zirconia has excellent mechanical properties comparable to metal, due to its microstructures. The properties of conventional zirconia were further improved by the composite in nano-scale such as zirconia/alumina nanocomposite (NANOZR. There are many interesting behaviors such as long-term stability related to low temperature degradation, effect of sandblasting and heat treatment on the microstructure and the strength, bonding to veneering porcelains, bonding to cement, visible light translucency related to esthetic restoration, X-ray opacity, biocompatibility, fracture load of clinical bridge as well as lifetime and clinical survival rates of the restoratives made with zirconia. From the recent material researches on zirconia not only in Japan but also in the world, this review takes into account these interesting properties of zirconia and reliability as core material for all-ceramic dental restorations.

  9. Investigation of high-temperature materials for uranium-fluoride-based gas core reactor systems

    Energy Technology Data Exchange (ETDEWEB)

    Collins, C.; Wang, S.C.P.; Anghaie, S.

    1988-01-01

    The development of the uranium-fluoride-based gas core reactor (GCR) systems will depend on the availability of wall materials that can survive the severe thermal, chemical, and nuclear environments of these systems. In the GCR system, the fuel/working fluid chemical constituents include enriched uranium fluorides UF{sub n} (n = 1 to 4) and fluorides operating at gas pressures of {approx}1 to 100 atm. The peak temperature of the fissioning gas/working fluid in the system can be 4000 K or higher, and the temperatures of the inner surface of the construction wall may exceed 1500 K. Wall materials that can be compatible in this environment must possess high melting points, good resistance to creep and thermal shock, and high resistance to fluorination. Compatible materials that feature high fluorination resistance are those that either do not react with fluorine/fluoride gases or those that can form a protective fluoride scale, which prevents or reduces further attack by the corrosive gas. Because fluorine and fluoride gases are strong oxidizing agents, formation of high melting point protective scales on substrate materials is more likely to be expected. This paper summarizes results of corrosion testing for evaluation of materials compatibility with uranium fluoride. These tests have been carried out by exposing different materials to UF{sub 6} gas in a closed capsule at temperatures up to 1500 K. Past exposure examinations were conducted to determine the morphology and composition of scales that were formed.

  10. Polyanion‐Type Electrode Materials for Sodium‐Ion Batteries

    Science.gov (United States)

    Ni, Qiao; Wu, Feng

    2017-01-01

    Sodium‐ion batteries, representative members of the post‐lithium‐battery club, are very attractive and promising for large‐scale energy storage applications. The increasing technological improvements in sodium‐ion batteries (Na‐ion batteries) are being driven by the demand for Na‐based electrode materials that are resource‐abundant, cost‐effective, and long lasting. Polyanion‐type compounds are among the most promising electrode materials for Na‐ion batteries due to their stability, safety, and suitable operating voltages. The most representative polyanion‐type electrode materials are Na3V2(PO4)3 and NaTi2(PO4)3 for Na‐based cathode and anode materials, respectively. Both show superior electrochemical properties and attractive prospects in terms of their development and application in Na‐ion batteries. Carbonophosphate Na3MnCO3PO4 and amorphous FePO4 have also recently emerged and are contributing to further developing the research scope of polyanion‐type Na‐ion batteries. However, the typical low conductivity and relatively low capacity performance of such materials still restrict their development. This paper presents a brief review of the research progress of polyanion‐type electrode materials for Na‐ion batteries, summarizing recent accomplishments, highlighting emerging strategies, and discussing the remaining challenges of such systems. PMID:28331782

  11. Adaptation of adhesive post and cores to dentin after in vitro occlusal loading: evaluation of post material influence

    OpenAIRE

    Dietschi, Didier; Ardu, Stefano; Rossier-Gerber, Anne; Krejci, Ivo

    2006-01-01

    Fatigue resistance of post and cores is critical to the long term behavior of restored nonvital teeth. The purpose of this in vitro trial was to evaluate the influence of the post material's physical properties on the adaptation of adhesive post and core restorations after cyclic mechanical loading.

  12. An efficient strategy for designing ambipolar organic semiconductor material: Introducing dehydrogenated phosphorus atoms into pentacene core

    Science.gov (United States)

    Tang, Xiao-Dan

    2017-09-01

    The charge transport properties of phosphapentacene (P-PEN) derivatives were systematically explored by theoretical calculation. The dehydrogenated P-PENs have reasonable frontier molecular orbital energy levels to facilitate both electron and hole injection. The reduced reorganization energies of dehydrogenated P-PENs could be intimately connected to the bonding nature of phosphorus atoms. From the idea of homology modeling, the crystal structure of TIPSE-4P-2p is constructed and fully optimized. Fascinatingly, TIPSE-4P-2p shows the intrinsic property of ambipolar transport in both hopping and band models. Thus, introducing dehydrogenated phosphorus atoms into pentacene core could be an efficient strategy for designing ambipolar material.

  13. Exfoliated BN shell-based high-frequency magnetic core-shell materials.

    Science.gov (United States)

    Zhang, Wei; Patel, Ketan; Ren, Shenqiang

    2017-09-14

    The miniaturization of electric machines demands high frequency magnetic materials with large magnetic-flux density and low energy loss to achieve a decreased dimension of high rotational speed motors. Herein, we report a solution-processed high frequency magnetic composite (containing a nanometal FeCo core and a boron nitride (BN) shell) that simultaneously exhibits high electrical resistivity and magnetic permeability. The frequency dependent complex initial permeability and the mechanical robustness of nanocomposites are intensely dependent on the content of BN insulating phase. The results shown here suggest that insulating magnetic nanocomposites have potential for application in next-generation high-frequency electric machines with large electrical resistivity and permeability.

  14. Finite element stress analysis of short-post core and over restorations prepared with different restorative materials.

    Science.gov (United States)

    Gurbuz, Taskin; Sengul, Fatih; Altun, Ceyhan

    2008-07-01

    The present study was conducted to determine the effect on the distribution of stress with the use of short-post cores and over restorations composed of different materials. The restorative materials used were namely two different composite resin materials (Valux Plus and Tetric Flow), a polyacid-modified resin material (Dyract AP), and a woven polyethylene fiber combination (Ribbond Fiber + Bonding agent + Tetric Flow). Finite element analysis (FEA) was used to develop a model for the maxillary primary anterior teeth. A masticatory force of 100 N was applied at 148 degrees to the incisal edge of the palatal surface of the crown model. Stress distributions and stress values were compared using von Mises criteria. The tooth model was assumed to be isotropic, homogeneous, elastic, and asymmetrical. It was observed that the highest stress usually occurred in the cervical area of the tooth when Tetric Flow was used as the short-post core and over restoration material. The same maximum stress value was also obtained when Ribbond fiber + Tetric Flow material was used for the short-post core. The results of FEA showed that the mechanical properties and elastic modulus of the restorative material influenced the stresses generated in enamel, dentin, and restoration when short-post core restorations were loaded incisally. Resin-based restorative materials with higher elastic moduli were found to be unsuitable as short-post core materials in endodontically treated maxillary primary anterior teeth.

  15. Matérn's hard core models of types I and II with arbitrary compact grains

    DEFF Research Database (Denmark)

    Kiderlen, Markus; Hörig, Mario

    Matérn's classical hard core models can be interpreted as models obtained from a stationary marked Poisson process by dependent thinning. The marks are balls of fixed radius, and a point is retained when its associated ball does not hit any other balls (type I) or when its random birth time is st...... of this model with the process of intact grains of the dead leaves model and the Stienen model leads to analogous results for the latter....

  16. Nickel/silicon core/shell nanosheet arrays as electrode materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Huang, X.H., E-mail: drhuangxh@hotmail.com; Zhang, P.; Wu, J.B.; Lin, Y.; Guo, R.Q.

    2016-08-15

    Highlights: • Ni nanosheet arrays is the core and Si layer is the shell. • Ni nanosheet arrays act as a three-dimensional current collector to support Si. • Ni nanosheet arrays can improve the conductivity and stability of the electrode. • Ni/Si nanosheet arrays exhibit excellent cyclic and rate performance. - Abstract: Ni/Si core/shell nanosheet arrays are proposed to enhance the electrochemical lithium-storage properties of silicon. The arrays are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The arrays are micro-sized in height, which are constructed by interconnected Ni nanosheet as the core and Si coating layer as the shell. The electrochemical properties as anode materials of lithium ion batteries are investigated by cyclic voltammetry (CV) and galvanostatic charge-discharge tests. The arrays can achieve high reversible capacity, good cycle stability and high rate capability. It is believed that the enhanced electrochemical performance is attributed to the electrode structure, because the interconnected Ni nanosheet can act as a three-dimensional current collector, and it has the ability of improving the electrode conductivity, enlarging the electrochemical reaction interface, and suppressing the electrode pulverization.

  17. The effect of Er,Cr:YSGG laser application on the micropush-out bond strength of fiber posts to resin core material.

    Science.gov (United States)

    Kurtulmus-Yilmaz, Sevcan; Cengiz, Esra; Ozan, Oguz; Ramoglu, Serhat; Yilmaz, Hasan Guney

    2014-10-01

    The aim of this study was to compare the effects of erbium, chromium: yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser application to different surface treatments on the micropush-out bond strengths between glass and quartz fiber posts and composite resin core material. Different types of lasers have been used as an alternative to airborne particle abrasion and other surface treatment methods to enhance the bond strength of dental materials. However, there is no study regarding the use of Er,Cr:YSGG laser as a surface treatment method for fiber posts in order to improve the bond strength. Ninety-six quartz and 96 glass fiber posts with a coronal diameter of 1.8 mm were randomly divided into eight groups according the surface treatments applied. Gr 1 (control, no surface treatment), Gr 2 (sandblasting with 50 μm Al2O3), Gr 3 (9 % hydrofluoric acid for 1 min), Gr 4 (24% H2O2 for 1 min), Gr 5 (CH2Cl2 for 1 min), Gr 6 (1 W), Gr 7 (1.5 W), and Gr 8 (2 W) Er,Cr:YSGG laser irradiation. The resin core material was applied to each group, and then 1 mm thick discs (n=12) were obtained for the micropush-out test. Data were statistically analyzed. For the quartz fiber post group, all surface treatments showed significantly higher micropush-out bond strengths than the control group (pstrength between the post and core material. However, the hydroflouric acid group showed the lowest bond strength values. The type of post and surface treatment might affect the bond strength between fiber posts and resin core material; 1 W and 1.5 W Er,Cr:YSGG laser application improved adhesion at the post/core interface.

  18. Core Genome Multilocus Sequence Typing Scheme for High-resolution Typing of Enterococcus faecium

    DEFF Research Database (Denmark)

    de Been, Mark; Pinholt, Mette; Top, Janetta

    2015-01-01

    Enterococcus faecium, a common inhabitant of the human gut, has emerged as an important multidrug-resistant nosocomial pathogen in the last two decades. Since the start of the 21(st) century, multi-locus sequence typing (MLST) has been used to study the molecular epidemiology of E. faecium. However...

  19. Modeling Overlapping Laminations in Magnetic Core Materials Using 2-D Finite-Element Analysis

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Guest, Emerson David; Mecrow, Barrie C.

    2015-01-01

    and a composite material is created, which has the same magnetization characteristic. The benefit of this technique is that it allows a designer to perform design and optimization of magnetic cores with overlapped laminations using a 2-D FE model rather than a 3-D FE model, which saves modeling and simulation...... time. The modeling technique is verified experimentally by creating a composite material of a lap joint with a 3-mm overlapping region and using it in a 2-D FE model of a ring sample made up of a stack of 20 laminations. The B-H curve of the simulated ring sample is compared with the B-H curve obtained...

  20. Bidirectional Thermo-Mechanical Properties of Foam Core Materials Using DIC

    DEFF Research Database (Denmark)

    Taher, Siavash Talebi; Thomsen, Ole Thybo; M Dulieu-Barton, Janice

    2011-01-01

    with an environmental chamber using specially designed grips that allow the specimen to rotate, and hence reduces paristic effects due to misalignment. The objective is to measure the unidirectional and bidirectional mechanical properties of PVC foam materials at elevated tempreature using digital image correlation......Polymer foam cored sandwich structures are often subjected to aggressive service conditions which may include elevated temperatures. A modified Arcan fixture (MAF) has been developed to characterize polymer foam materials with respect to their tensile, compressive, shear and bidirectional...... mechanical properties at room and at elevated temperatures. The MAF enables the realization of pure compression or high compression to shear bidirectional loading conditions that is not possible with conventional Arcan fixtures. The MAF is attached to a standard universal test machine equiped...

  1. Mechanism of hollow-core-fiber infrared-supercontinuum compression with bulk material

    Science.gov (United States)

    Béjot, P.; Schmidt, B. E.; Kasparian, J.; Wolf, J.-P.; Legaré, F.

    2010-06-01

    We numerically investigate the pulse compression mechanism in the infrared spectral range based on the successive action of nonlinear pulse propagation in a hollow-core fiber followed by linear propagation through bulk material. We found an excellent agreement of simulated pulse properties with experimental results at 1.8 μm in the two-optical-cycle regime close to the Fourier limit. In particular, the spectral phase asymmetry attributable to self-steepening combined with self-phase modulation is a necessary prerequisite for subsequent compensation by the phase introduced by glass material in the anomalous dispersion regime. The excellent agreement of the model enabled simulating pressure and wavelength tunability of sub-two cycles in the range from 1.5 to 4 μm with this cost-efficient and robust approach.

  2. Development of core fuel management code system for WWER-type reactors

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this article, a core fuel management program for hexagonal pressurized water type WWER reactors (CFMHEX) has been developed, which is based on advanced three-dimensional nodal method and integrated with thermal hydraulic code to realize the coupling of neutronics and thermal-hydraulics. In CFMHEX, all these feedback effects such as burnup, power distribution, moderator density, and control rod insertion are considered. The verification and validation of the code system have been examined through the IAEA WWER-1000-type Kalinin NPP benchmark problem. The numerical results are in good agreement with measurements and are close to those of other international institutes.

  3. Preparation of A New Type of Stress-absorbed Material

    Institute of Scientific and Technical Information of China (English)

    WU Shao-peng; YANG Tao; YUAN Hai-qing

    2004-01-01

    Neoprene latex modified emulsified bitumen and fine aggregate are used to prepare a new type of stress-absorbed material, which has strong ability of anti-reflective cracking on asphalt concrete over layer-constructed upon a semi-rigid type base course or cement concrete pavement block. Experimental results demonstrate the stress-absorbed material have excellent mechanical properties including a low modulus of elasticity, high ultimate tensile stress and strain, and a strong distortion ability. Stress concentration in asphalt over layer originated by temperature changes and traffic loads can be alleviated.

  4. Designing small molecule polyaromatic p- and n-type semiconductor materials for organic electronics

    KAUST Repository

    Collis, Gavin E.

    2015-12-22

    By combining computational aided design with synthetic chemistry, we are able to identify core 2D polyaromatic small molecule templates with the necessary optoelectronic properties for p- and n-type materials. By judicious selection of the functional groups, we can tune the physical properties of the material making them amenable to solution and vacuum deposition. In addition to solubility, we observe that the functional group can influence the thin film molecular packing. By developing structure-property relationships (SPRs) for these families of compounds we observe that some compounds are better suited for use in organic solar cells, while others, varying only slightly in structure, are favoured in organic field effect transistor devices. We also find that the processing conditions can have a dramatic impact on molecular packing (i.e. 1D vs 2D polymorphism) and charge mobility; this has implications for material and device long term stability. We have developed small molecule p- and n-type materials for organic solar cells with efficiencies exceeding 2%. Subtle variations in the functional groups of these materials produces p- and ntype materials with mobilities higher than 0.3 cm2/Vs. We are also interested in using our SPR approach to develop materials for sensor and bioelectronic applications.

  5. Designing small molecule polyaromatic p- and n-type semiconductor materials for organic electronics

    Science.gov (United States)

    Collis, Gavin E.

    2015-12-01

    By combining computational aided design with synthetic chemistry, we are able to identify core 2D polyaromatic small molecule templates with the necessary optoelectronic properties for p- and n-type materials. By judicious selection of the functional groups, we can tune the physical properties of the material making them amenable to solution and vacuum deposition. In addition to solubility, we observe that the functional group can influence the thin film molecular packing. By developing structure-property relationships (SPRs) for these families of compounds we observe that some compounds are better suited for use in organic solar cells, while others, varying only slightly in structure, are favoured in organic field effect transistor devices. We also find that the processing conditions can have a dramatic impact on molecular packing (i.e. 1D vs 2D polymorphism) and charge mobility; this has implications for material and device long term stability. We have developed small molecule p- and n-type materials for organic solar cells with efficiencies exceeding 2%. Subtle variations in the functional groups of these materials produces p- and ntype materials with mobilities higher than 0.3 cm2/Vs. We are also interested in using our SPR approach to develop materials for sensor and bioelectronic applications.

  6. Analysis on Band Gaps of MCM-41 Type of Materials

    Institute of Scientific and Technical Information of China (English)

    HAN Pei-de; LIANG Jian; XU Bing-she; LIU Xu-guang; PENG Lian-mao

    2004-01-01

    The concept and analysis method of photonic crystals and band gaps are introduced into one-dimensional(1D) ordered mesoporous materials. MCM-41 type of materials are treated theoretically as photonic crystals. The formation of band gaps is exhibited and confirmed by a calculation of transfer matrix technique. PBG was found around 9-42 nm in soft X-ray region. The photonic band-gap was predicted to be dependent on incident direction, pore size and lattice constant. The mesoporous materials with different pore sizes and different lattice constants have different band-gap widths.

  7. ZnO-nanocarbon core-shell type hybrid quantum dots

    CERN Document Server

    Choi, Won Kook

    2017-01-01

    This book offers a comprehensive overview of ZnO-nano carbon core shell hybrid issues. There is significant interest in metal oxide/nanocarbon hybrid functional materials in the field of energy conversion and storage as electrode materials for supercapacitors, Li ion secondary battery, electrocatalysts for water splitting, and optoelectronic devices such as light emitting diodes and solar photovoltaic cells. Despite efforts to manipulate more uniform metal oxide-nanocarbon nanocomposite structures, they have shown poor performance because they are randomly scattered and non-uniformly attached to the nanocarbon surface. For higher and more effective performance of the hybrid structure, 3D conformal coating on metal oxides are highly desirable. In the first part of the book, the physical and chemical properties of ZnO and nanocarbons and the state-of-the-art in related research are briefly summarized. In the next part, the 3D conformal coating synthetic processes of ZnO templated nanocarbon hybrid materials suc...

  8. Assessment of the Possibility of Using Reclaimed Materials for Making Cores by the Blowing Method

    Directory of Open Access Journals (Sweden)

    Dańko R.

    2017-03-01

    Full Text Available The cumulative results of investigations of the possibility of using the reclaimed materials after the mechanical, thermal or mechanical-thermal reclamation for making cores by means of the blowing method in the alkaline CO2 technology, are presented in the paper. Three kinds of spent sands: with furfuryl resin, bentonite and alkaline phenolic resin, obtained from the foundry, were subjected to three kinds of reclamation: mechanical, thermal and combined mechanical-thermal, applying for this aim adequate experimental devices. The obtained reclaims were assessed with regard to the degree of the matrix liberation from the determined binding material. Reclaims of moulding sands with binders of the form of resin were assessed with regard to ignition loss values and pH reaction, while reclaims of moulding sands with bentonite with regard to the residual clay content and pH value. In all cases the results of the performed sieve analyses were estimated and the average characteristic diameter dl was determined. The reclaimed matrix was applied as a full substitute of the fresh high-silica sand in typical procedures of preparing core sands used for making shaped samples for bending strength investigations, Rgu.

  9. Depleted cores, multi-component fits, and structural parameter relations for luminous early-type galaxies

    CERN Document Server

    Dullo, Bililign T

    2013-01-01

    New surface brightness profiles from 26 early-type galaxies with partially depleted cores have been extracted from the full radial extent of Hubble Space Telescope images, giving us a total sample of 31 such core-Sersic galaxies. We have carefully quantified the radial stellar distributions of the elliptical galaxies using the core-Sersic model whereas for the lenticular galaxies a core-Sersic bulge plus an exponential disc model gives the best representation. We additionally caution about the excessive use of multiple Sersic functions for decomposing galaxies. The structural parameters obtained from our fitted models are used to update several `central' as well as `global' galaxy scaling relations. We find near-linear relations between the break radius R_b and the spheroid luminosity L such that R_b ~ L^(1.13 +/- 0.13), and with the supermassive black hole mass M_BH such that R_b ~ M_BH^(0.83+/- 0.21). This is internally consistent with the notion that major, dry mergers add the stellar and black hole mass i...

  10. Long gamma-ray Bursts and Type Ic Core CollapseSupernovae have Similar Environments

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, P.L.; Kirshner, R.P.; Pahre, M.

    2007-12-04

    When the afterglow fades at the site of a long-duration {gamma}-ray burst (LGRB), Type Ic supernovae (SN Ic) are the only type of core collapse supernova observed. Recent work found that a sample of LGRB had different environments from a collection of core-collapse supernovae identified in a high-redshift sample from colors and light curves. LGRB were in the brightest regions of their hosts, but the core-collapse sample followed the overall distribution of the galaxy light. Here we examine 263 fully spectroscopically-typed supernovae found in nearby (z < 0.06) galaxies for which we have constructed surface photometry from the Sloan Digital Sky Survey (SDSS). The distributions of the thermonuclear supernovae (SN Ia) and some varieties of core-collapse supernovae (SN II and SN Ib) follow the galaxy light, but the SN Ic (like LGRB) are much more likely to erupt in the brightest regions of their hosts. The high-redshift hosts of LGRB are overwhelmingly irregulars, without bulges, while many low redshift SN Ic hosts are spirals with small bulges. When we remove the bulge light from our low-redshift sample, the SN Ic and LGRB distributions agree extremely well. If both LGRB and SN Ic stem from very massive stars, then it seems plausible that the conditions necessary for forming SN Ic are also required for LGRB. Additional factors, including metallicity, may determine whether the stellar evolution of a massive star leads to a LGRB with an underlying broad-lined SN Ic, or simply a SN Ic without a {gamma}-ray burst.

  11. Preliminary Thermal Hydraulic Analyses of the Conceptual Core Models with Tubular Type Fuel Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Chae, Hee Taek; Park, Jong Hark; Park, Cheol

    2006-11-15

    A new research reactor (AHR, Advanced HANARO Reactor) based on the HANARO has being conceptually developed for the future needs of research reactors. A tubular type fuel was considered as one of the fuel options of the AHR. A tubular type fuel assembly has several curved fuel plates arranged with a constant small gap to build up cooling channels, which is very similar to an annulus pipe with many layers. This report presents the preliminary analysis of thermal hydraulic characteristics and safety margins for three conceptual core models using tubular fuel assemblies. Four design criteria, which are the fuel temperature, ONB (Onset of Nucleate Boiling) margin, minimum DNBR (Departure from Nucleate Boiling Ratio) and OFIR (Onset of Flow Instability Ratio), were investigated along with various core flow velocities in the normal operating conditions. And the primary coolant flow rate based a conceptual core model was suggested as a design information for the process design of the primary cooling system. The computational fluid dynamics analysis was also carried out to evaluate the coolant velocity distributions between tubular channels and the pressure drop characteristics of the tubular fuel assembly.

  12. Statics and kinematics of discrete Cosserat-type granular materials

    NARCIS (Netherlands)

    Kruyt, N.P.

    2003-01-01

    A theoretical framework is presented for the statics and kinematics of discrete Cosserat-type granular materials. In analogy to the force and moment equilibrium equations for particles, compatibility equations for closed loops are formulated in the two-dimensional case for relative displacements and

  13. Simulations of core convection in rotating A-type stars: Magnetic dynamo action

    CERN Document Server

    Brun, A S; Toomre, J; Brun, Allan Sacha; Browning, Matthew K.; Toomre, Juri

    2005-01-01

    Core convection and dynamo activity deep within rotating A-type stars of 2 solar masses are studied with 3--D nonlinear simulations. Our modeling considers the inner 30% by radius of such stars, thus capturing within a spherical domain the convective core and a modest portion of the surrounding radiative envelope. The MHD equations are solved using the ASH code to examine turbulent flows and magnetic fields, both of which exhibit intricate time dependence. By introducing small seed magnetic fields into our progenitor hydrodynamic models rotating at one and four times the solar rate, we assess here how the vigorous convection can amplify those fields and sustain them against ohmic decay. Dynamo action is indeed realized, ultimately yielding magnetic fields that are in energy equipartion with the flow. Such magnetism reduces the differential rotation obtained in the progenitors, partly by Maxwell stresses that transport angular momentum poleward and oppose the Reynolds stresses in the latitudinal balance. In co...

  14. Shear bond strength of four resin cements used to lute ceramic core material to human dentin.

    Science.gov (United States)

    Altintas, Subutayhan; Eldeniz, Ayçe Unverdi; Usumez, Aslihan

    2008-12-01

    This study evaluated the effect of four resin cements on the shear bond strength of a ceramic core material to dentin. One hundred twenty molar teeth were embedded in a self-curing acrylic resin. The occlusal third of the crowns were sectioned under water cooling. All specimens were randomly divided into four groups of 30 teeth each according to the resin cement used. One hundred twenty cylindrical-shaped, 2.7-mm wide, 3-mm high ceramic core materials were heat-pressed. The core cylinders were then luted with one of the four resin systems to dentin (Super-Bond C&B, Chemiace II, Variolink II, and Panavia F). Half of the specimens (n = 15) were tested after 24 hours; the other half (n = 15) were stored in distilled water at 37 degrees C for 1 day and then thermocycled 1000 times between 5 degrees C and 55 degrees C prior to testing. Shear bond strength of each specimen was measured using a universal testing machine at a crosshead speed of 1 mm/min. The bond strength values were calculated in MPa, and the results were statistically analyzed using a two-way analysis of variance (ANOVA) and Tukey HSD tests. The shear bond strength varied significantly depending on the resin cement used (p strengths after thermocycling were not remarkable as compared with the corresponding prethermal cycling groups (p > 0.05). Significant interactions were present between resin cement and thermocycling (p strength, whereas the specimens luted with Chemiace II (1.6 +/- 0.4 MPa) showed the lowest. After thermocycling, the bond strength values of specimens luted with Chemiace II (1.1 +/- 0.1 MPa) and Super-Bond C&B (1.7 +/- 0.4 MPa) decreased; however, this was not statistically significant (p > 0.05). The increase in the shear bond strength values in the Panavia F (4.5 +/- 0.7 MPa) and Variolink II (5.5 +/- 2.1 MPa) groups after thermocycling was also not statistically significant (p > 0.05). Variolink II and Panavia F systems showed higher shear bond strength values than Chemiace II and

  15. Effect of Different Surface Treatment on Shear Bond Strength of Veneering Composite to Polyetherketone Core Material

    Directory of Open Access Journals (Sweden)

    Hossein Pourkhalili

    2016-12-01

    Full Text Available Background and Objective:The purpose of this in vitro study was to assess the effect of different surface treatment methods on shear bond strength of the veneering composite to polyetheretherketone (PEEK core material. Materials and Methods::In this in vitro, experimental study, 60 PEEK discs were fabricated, polished with silicon carbide abrasive paper and divided into five surface treatment groups (n=12 namely air abrasion with 110µm alumina particles at 0.2MPa pressure for 10 seconds, 98% sulfuric acid etching for one minute, air abrasion plus sulfuric acid etching, application of cyanoacrylate resin and a no surface treatment control group. Visio.link adhesive and GC Gradia veneering composite were applied on PEEK surfaces and light-cured. Shear bond strength was measured using a universal testing machine and the data were analyzed by one-way ANOVA and Tukey’s test. Results:The mean ± standard deviation (SD values of shear bond strength of the veneering composite to PEEK surfaces were 8.85±3.03, 15.6±5.02, 30.42±5.43, 26.14±4.33 and 5.94±4.49MPa in the control, air-abrasion, sulfuric acid etching, air-abrasion plus sulfuric acid etching and cyanoacrylate resin groups, respectively. The control and cyanoacrylate groups had significant differences with air abrasion, sulfuric acid etching and air abrasion plus sulfuric acid etching groups in terms of shear bond strength (P<0.0001. Higher bond strength values were noted in sulfuric acid etching, air-abrasion plus sulfuric acid etching and air abrasion groups compared to the control and cyanoacrylate groups (P<0.0001. Conclusion:Sulfuric acid etching, air abrasion and a combination of both are recommended as efficient surface treatments to increase the shear bond strength of the veneering composite to PEEK core material.

  16. Genomics and transcriptomics of Xanthomonas campestris species challenge the concept of core type III effectome.

    Science.gov (United States)

    Roux, Brice; Bolot, Stéphanie; Guy, Endrick; Denancé, Nicolas; Lautier, Martine; Jardinaud, Marie-Françoise; Fischer-Le Saux, Marion; Portier, Perrine; Jacques, Marie-Agnès; Gagnevin, Lionel; Pruvost, Olivier; Lauber, Emmanuelle; Arlat, Matthieu; Carrère, Sébastien; Koebnik, Ralf; Noël, Laurent D

    2015-11-18

    The bacterial species Xanthomonas campestris infects a wide range of Brassicaceae. Specific pathovars of this species cause black rot (pv. campestris), bacterial blight of stock (pv. incanae) or bacterial leaf spot (pv. raphani). In this study, we extended the genomic coverage of the species by sequencing and annotating the genomes of strains from pathovar incanae (CFBP 1606R and CFBP 2527R), pathovar raphani (CFBP 5828R) and a pathovar formerly named barbareae (CFBP 5825R). While comparative analyses identified a large core ORFeome at the species level, the core type III effectome was limited to only three putative type III effectors (XopP, XopF1 and XopAL1). In Xanthomonas, these effector proteins are injected inside the plant cells by the type III secretion system and contribute collectively to virulence. A deep and strand-specific RNA sequencing strategy was adopted in order to experimentally refine genome annotation for strain CFBP 5828R. This approach also allowed the experimental definition of novel ORFs and non-coding RNA transcripts. Using a constitutively active allele of hrpG, a master regulator of the type III secretion system, a HrpG-dependent regulon of 141 genes co-regulated with the type III secretion system was identified. Importantly, all these genes but seven are positively regulated by HrpG and 56 of those encode components of the Hrp type III secretion system and putative effector proteins. This dataset is an important resource to mine for novel type III effector proteins as well as for bacterial genes which could contribute to pathogenicity of X. campestris.

  17. Safety analysis for operating the Annular Core Research Reactor with Cintichem-type targets installed in the central region of the core

    Energy Technology Data Exchange (ETDEWEB)

    PARMA JR.,EDWARD J.

    2000-01-01

    Production of the molybdenum-99 isotope at the Annular Core Research Reactor requires highly enriched, uranium oxide loaded targets to be irradiated for several days in the high neutron-flux region of the core. This report presents the safety analysis for the irradiation of up to seven Cintichem-type targets in the central region of the core and compares the results to the Annular Core Research Reactor Safety Analysis Report. A 19 target grid configuration is presented that allows one to seven targets to be irradiated, with the remainder of the grid locations filled with aluminum ''void'' targets. Analyses of reactor, neutronic, thermal hydraulics, and heat transfer calculations are presented. Steady-state operation and accident scenarios are analyzed with the conclusion that the reactor can be operated safely with seven targets in the grid, and no additional risk to the public.

  18. Surfactant-Mediated Conformal Overgrowth of Core-Shell Metal-Organic Framework Materials with Mismatched Topologies.

    Science.gov (United States)

    Zhuang, Jia; Chou, Lien-Yang; Sneed, Brian T; Cao, Yingze; Hu, Pan; Feng, Lin; Tsung, Chia-Kuang

    2015-11-04

    Fracture-free and conformal Pd-UiO-66@ZIF-8 core-shell metal-organic framework material is synthesized by a surfactant-mediated method. The hierarchical nanoporous material exhibits great size-selective hydrogenation catalysis and demonstrates potentials for many different applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. The CERN antiproton target: hydrocode analysis of its core material dynamic response under proton beam impact

    CERN Document Server

    Martin, Claudio Torregrosa; Calviani, Marco; Muñoz-Cobo, José-Luis

    2016-01-01

    Antiprotons are produced at CERN by colliding a 26 GeV/c proton beam with a fixed target made of a 3 mm diameter, 55 mm length iridium core. The inherent characteristics of antiproton production involve extremely high energy depositions inside the target when impacted by each primary proton beam, making it one of the most dynamically demanding among high energy solid targets in the world, with a rise temperature above 2000 {\\deg}C after each pulse impact and successive dynamic pressure waves of the order of GPa's. An optimized redesign of the current target is foreseen for the next 20 years of operation. As a first step in the design procedure, this numerical study delves into the fundamental phenomena present in the target material core under proton pulse impact and subsequent pressure wave propagation by the use of hydrocodes. Three major phenomena have been identified, (i) the dominance of a high frequency radial wave which produces destructive compressive-to-tensile pressure response (ii) The existence of...

  20. CERN antiproton target: Hydrocode analysis of its core material dynamic response under proton beam impact

    Science.gov (United States)

    Martin, Claudio Torregrosa; Perillo-Marcone, Antonio; Calviani, Marco; Muñoz-Cobo, José-Luis

    2016-07-01

    Antiprotons are produced at CERN by colliding a 26 GeV /c proton beam with a fixed target made of a 3 mm diameter, 55 mm length iridium core. The inherent characteristics of antiproton production involve extremely high energy depositions inside the target when impacted by each primary proton beam, making it one of the most dynamically demanding among high energy solid targets in the world, with a rise temperature above 2000 °C after each pulse impact and successive dynamic pressure waves of the order of GPa's. An optimized redesign of the current target is foreseen for the next 20 years of operation. As a first step in the design procedure, this numerical study delves into the fundamental phenomena present in the target material core under proton pulse impact and subsequent pressure wave propagation by the use of hydrocodes. Three major phenomena have been identified, (i) the dominance of a high frequency radial wave which produces destructive compressive-to-tensile pressure response (ii) The existence of end-of-pulse tensile waves and its relevance on the overall response (iii) A reduction of 44% in tensile pressure could be obtained by the use of a high density tantalum cladding.

  1. Derivation of temperature dependent mechanical properties of polymer foam core materials using optical extensometry

    Directory of Open Access Journals (Sweden)

    Fruehmann R.K.

    2010-06-01

    Full Text Available A methodology for determining the temperature dependence of Young’s modulus and Poisson’s ratio of polymer foams core materials is presented. The design of the test specimen is described in detail, covering the parasitic effects resulting from departures from the uniform strain condition. The measurement approach is based on a non-contact technique so that the behaviour of the complaint foam is not modified by the attachment of strain gauges or extensometers. Firstly experiments are conducted at room temperature and then at elevated temperatures in a thermal chamber. Readings are taken through an optical window using a standard digital camera. Digital image correlation is used to obtain the strains.

  2. Enhanced Materials Based on Submonolayer Type-II Quantum Dots

    Energy Technology Data Exchange (ETDEWEB)

    Tamargo, Maria C [City College of New York, NY (United States); Kuskovsky, Igor L. [City Univ. (CUNY), NY (United States) Queens College; Meriles, Carlos [City College of New York, NY (United States); Noyan, Ismail C. [Columbia Univ., New York, NY (United States)

    2017-04-15

    We have investigated a nanostructured material known as sub-monolayer type-II QDs, made from wide bandgap II-VI semiconductors. Our goal is to understand and exploit their tunable optical and electrical properties by taking advantage of the type-II band alignment and quantum confinement effects. Type-II ZnTe quantum dots (QDs) in a ZnSe host are particularly interesting because of their relatively large valence band and conduction band offsets. In the current award we have developed new materials based on sub-monolayer type-II QDs that may be advantageous for photovoltaic and spintronics applications. We have also expanded the structural characterization of these materials by refining the X-ray diffraction methodologies needed to investigate them. In particular, we have 1) demonstrated ZnCdTe/ZnCdSe type-II QDs materials that have ideal properties for the development of novel high efficiency “intermediate band solar cells”, 2) we developed a comprehensive approach to describe and model the growth of these ultra-small type-II QDs, 3) analysis of the evolution of the photoluminescence (PL) emission, combined with other characterization probes allowed us to predict the size and density of the QDs as a function of the growth conditions, 4) we developed and implemented novel sophisticated X-ray diffraction techniques from which accurate size and shape of the buried type-II QDs could be extracted, 5) a correlation of the shape anisotropy with polarization dependent PL was observed, confirming the QDs detailed shape and providing insight about the effects of this shape anisotropy on the physical properties of the type-II QD systems, and 6) a detailed “time-resolved Kerr rotation” investigation has led to the demonstration of enhanced electron spin lifetimes for the samples with large densities of type-II QDs and an understanding of the interplay between the QDs and Te-isoelectroic centers, a defect that forms in the spacer layers that separate the QDs.

  3. Cereblon inhibits proteasome activity by binding to the 20S core proteasome subunit beta type 4.

    Science.gov (United States)

    Lee, Kwang Min; Lee, Jongwon; Park, Chul-Seung

    2012-10-26

    In humans, mutations in the gene encoding cereblon (CRBN) are associated with mental retardation. Although CRBN has been investigated in several cellular contexts, its function remains unclear. Here, we demonstrate that CRBN plays a role in regulating the ubiquitin-proteasome system (UPS). Heterologous expression of CRBN inhibited proteasome activity in a human neuroblastoma cell line. Furthermore, proteasome subunit beta type 4 (PSMB4), the β7 subunit of the 20S core complex, was identified as a direct binding partner of CRBN. These findings suggest that CRBN may modulate proteasome activity by directly interacting with the β7 subunit.

  4. Preparation and mechanical property of core-shell type chitosan/calcium phosphate composite fiber

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Atsushi [Japan Society for the Promotion of Science, Ikenohata1-1-1, Daitou-ku, Tokyo 110-0008 (Japan) and Creative Research Initiative ' Sousei' , Hokkaido University, Sapporo, Hokkaido 001-0021 (Japan)]. E-mail: MATSUDA.Atsushi@nims.go.jp; Ikoma, Toshiyuki [Biomaterials Research Center, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan); Kobayashi, Hisatoshi [Biomaterials Research Center, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan)]. E-mail: Kobayashi.Hisatoshi@nims.go.jp; Tanaka, Junzo [Creative Research Initiative ' Sousei' , Hokkaido University, Sapporo, Hokkaido 001-0021 (Japan); Biomaterials Research Center, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan)

    2004-12-01

    Core-shell type chitosan/calcium phosphate composite fibers were prepared by a facile wet spinning method; the chitosan aqueous solution with PO{sub 4} ions was dropped and coagulated in the ethanol/calcium hydroxide solutions at different mixed ratio. X-ray diffraction (XRD) patterns indicated that the crystal phases of calcium phosphates in the composite fibers were a low-crystalline hydroxyapatite (HAp; Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2})or the low-crystalline hydroxyapatite/brushite mixture depended on the ratio of ethanol/calcium hydroxide solutions. The inorganic contents were ca. 60 wt.% by using the TG-DTA analysis. The energy-dispersive X-ray spectroscopy (EDS) analysis indicated that Ca and P atoms were mainly distributed on the outer layer of the composite fiber to grow calcium phosphate crystals; however, a little amount of P atom still remained at the inside of the fiber. This indicated that the composite fibers formed a unique core-shell structure with shell of calcium phosphate and core of chitosan. The mechanical property of the fibers was reinforced by the initial concentration of chitosan solution.

  5. Type of speech material affects Acceptable Noise Level test outcome

    Directory of Open Access Journals (Sweden)

    Xaver eKoch

    2016-02-01

    Full Text Available The Acceptable Noise Level (ANL test, in which individuals indicate what level of noise they are willing to put up with while following speech, has been used to guide hearing aid fitting decisions and has been found to relate to prospective hearing aid use. Unlike objective measures of speech perception ability, ANL outcome is not related to individual hearing loss or age, but rather reflects an individual's inherent acceptance of competing noise while listening to speech. As such, the measure may predict aspects of hearing aid success. Crucially, however, recent studies have questioned its repeatability (test-retest reliability. The first question for this study was whether the inconsistent results regarding the repeatability of the ANL test may be due to differences in speech material types used in previous studies. Second, it is unclear whether meaningfulness and semantic coherence of the speech modify ANL outcome. To investigate these questions, we compared ANLs obtained with three types of materials: the International Speech Test Signal (ISTS, which is non-meaningful and semantically non-coherent by definition, passages consisting of concatenated meaningful standard audiology sentences, and longer fragments taken from conversational speech. We included conversational speech as this type of speech material is most representative of everyday listening. Additionally, we investigated whether ANL outcomes, obtained with these three different speech materials, were associated with self-reported limitations due to hearing problems and listening effort in everyday life, as assessed by a questionnaire. ANL data were collected for 57 relatively good-hearing adult participants with an age range representative for hearing aid users. Results showed that meaningfulness, but not semantic coherence of the speech material affected ANL. Less noise was accepted for the non-meaningful ISTS signal than for the meaningful speech materials. ANL repeatability was

  6. Repairing rabbit radial defects by combining bone marrow stroma stem cells with bone scaffold material comprising a core-cladding structure.

    Science.gov (United States)

    Wu, H; Liu, G H; Wu, Q; Yu, B

    2015-10-05

    We prepared a bone scaffold material comprising a PLGA/β-TCP core and a Type I collagen cladding, and recombined it with bone marrow stroma stem cells (BMSCs) to evaluate its potential for use in bone tissue engineering by in vivo and in vitro experiments. PLGA/β-TCP without a cladding was used for comparison. The adherence rate of the BMSCs to the scaffold was determined by cell counting. Cell proliferation rate was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. The osteogenic capability was evaluated by alkaline phosphatase activity. The scaffold materials were recombined with the BMSCs and implanted into a large segmental rabbit radial defect model to evaluate defect repair. Osteogenesis was assessed in the scaffold materials by histological and double immunofluorescence labeling, etc. The adherence number, proliferation number, and alkaline phosphatase expression of the cells on the bone scaffold material with core-cladding structure were significantly higher than the corresponding values in the PLGA/β-TCP composite scaffold material (P cladding structure completely degraded at the bone defect site and bone formation was completed. The rabbit large sentimental radial defect was successfully repaired. The degradation and osteogenesis rates matched well. The bone scaffold with core-cladding structure exhibited better osteogenic activity and capacity to repair a large segmental bone defect compared to the PLGA/β-TCP composite scaffold. The bone scaffold with core-cladding structure has excellent physical properties and biocompatibility. It is an ideal scaffold material for bone tissue engineering.

  7. Interfacial characterization of ceramic core materials with veneering porcelain for all-ceramic bi-layered restorative systems.

    Science.gov (United States)

    Tagmatarchis, Alexander; Tripodakis, Aris-Petros; Filippatos, Gerasimos; Zinelis, Spiros; Eliades, George

    2014-01-01

    The aim of the study was to characterize the elemental distribution at the interface between all-ceramic core and veneering porcelain materials. Three groups of all-ceramic cores were selected: A) Glass-ceramics (Cergo, IPS Empress, IPS Empress 2, e-max Press, Finesse); B) Glass-infiltrated ceramics (Celay Alumina, Celay Zirconia) and C) Densely sintered ceramics (Cercon, Procera Alumina, ZirCAD, Noritake Zirconia). The cores were combined with compatible veneering porcelains and three flat square test specimens were produced for each system. The core-veneer interfaces were examined by scanning electron microscopy and energy dispersive x-ray microanalysis. The glass-ceramic systems showed interfacial zones reach in Si and O, with the presence of K, Ca, Al in core and Ca, Ce, Na, Mg or Al in veneer material, depending on the system tested. IPS Empress and IPS Empress 2 demonstrated distinct transitional phases at the core-veneer interface. In the glassinfiltrated systems, intermixing of core (Ce, La) with veneer (Na, Si) elements occurred, whereas an abrupt drop of the core-veneer elemental concentration was documented at the interfaces of all densely sintered ceramics. The results of the study provided no evidence of elemental interdiffusion at the core-veneer interfaces in densely sintered ceramics, which implies lack of primary chemical bonding. For the glass-containing systems (glassceramics and glass-infiltrated ceramics) interdiffusion of the glass-phase seems to play a critical role in establishing a primary bonding condition between ceramic core and veneering porcelain.

  8. Novel Polymer Resistive-type Humidity Sensitive Materials

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Results Humidity sensors have been widely investigated in recent years[1,2].In this work,two kinds of polymer resistive-type humidity sensitive materials were prepared as follows: 1) polymer electrolyte with an IPN structure formed by the simultaneous quaternization and crosslinking of poly(4-vinylpyridine) (P4VP) and poly(glycidyl methacrylate) (PGMA) with 1,4-dibromobutane (DBB) and diethyltriamine (DETA) respectively; 2) silicon-containing polyelectrolyte with crosslinking structure formed by a sim...

  9. Solitons in a hard-core bosonic system: Gross–Pitaevskii type and beyond

    Indian Academy of Sciences (India)

    Radha Balakrishnan; Indubala I Satija

    2015-11-01

    We present a unified formulation to investigate solitons for all background densities in the Bose–Einstein condensate of a system of hard-core bosons with nearest-neighbour attractive interactions, using an extended Bose–Hubbard lattice model. We derive in detail the characteristics of the solitons supported in the continuum version, for the various cases possible. In general, two species of solitons appear: A nonpersistent (NP) type that fully delocalizes at its maximum speed and a persistent (P) type that survives even at its maximum speed. When the background condensate density is nonzero, both species coexist, the soliton is associated with a constant intrinsic frequency, and its maximum speed is the speed of sound. In contrast, when the background condensate density is zero, the system has neither a fixed frequency, nor a speed of sound. Here, the maximum soliton speed depends on the frequency, which can be tuned to lead to a cross-over between the NP-type and the P-type at a certain critical frequency, determined by the energy parameters of the system. We provide a single functional form for the soliton profile, from which diverse characteristics for various background densities can be obtained. Using mapping to spin systems enables us to characterize, in a unified fashion, the corresponding class of magnetic solitons in Heisenberg spin chains with different types of anisotropy.

  10. Unifying Type II Supernova Light Curves with Dense Circumstellar Material

    CERN Document Server

    Morozova, Viktoriya; Valenti, Stefano

    2016-01-01

    A longstanding problem in the study of supernovae (SNe) has been the relationship between the Type IIP and Type IIL subclasses. Whether they come from distinct progenitors or they are from similar stars with some property that smoothly transitions from one class to another has been the subject of much debate. Here we show using one-dimensional radiation-hydrodynamic SN models that the multi-band light curves of SNe IIL are well fit by ordinary red supergiants surrounded by dense circumstellar material (CSM). The inferred extent of this material, coupled with a typical wind velocity of ~10-100 km/s, suggests enhanced activity by these stars during the last ~months to ~years of their lives, which may be connected with advanced stages of nuclear burning. Furthermore, we find that even for more plateau-like SNe that dense CSM provides a better fit to the first ~20 days of their light curves, indicating that the presence of such material may be more widespread than previously appreciated. Here we choose to model t...

  11. MELTSPREAD-1 calculations of the transient spreading of core materials in the KNGR

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yong Mann; Park, Soo Yong

    1999-03-01

    Major purpose of the report is to predict whether or not the melt will spread to cover the full floor area under severe accident conditions in KNGR (Korea Next Generation Reactor) cavity and to determine the local distribution of spread material depth as well as concrete attack upon the cavity floor. For this analysis, MELTSPREAD-1 computer code developed at ANL (Argonne National Laboratory) is first applied domestically. This code was originally developed to model the discharge of corium from the vessel and its spreading on the floor of a prototypical BWR Mark 1 containment, but is known to have the flexibility of LWR application via user-specified nodalization scheme. The analysis methodology in this report is assessed to be valid by independent ABB-CE review [ABB-CE 1988]. For the conservative analysis of melt spreading and erosion characteristics, a medium LOCA (loss of coolant accident) as the typical in-vessel low pressure accident, with 100% core mass release into the wet cavity is chosen as the basic sequence. For specified conditions of release from the failed reactor vessel lower head, the core materials are calculated to spread within a very short time and cover the full accessible cavity floor area. The spreading profiles are shown as a scene view according to time with detailed predictions of the extent of local melting-induced erosion of the concrete floor. The MELTSPREAD-1 results are important to the assessment of melt coolability following the transients spreading phase, and the results of the basic LOCA sequence can serve as the bounding calculation in the melt spreading and ablation for the KNGR cavity. In addition to this, sensitivity studies are made for important factors and crust formation and heat transfer models together with initial cavity condition and initial corium mass/temperature are appeared to be significant for the results. For the last, both MELTSPREAD-1 code input deck and calculation note used for the sequence analysis are

  12. Evaluation of different graft material in type 1 tympanoplasty

    Directory of Open Access Journals (Sweden)

    Kshitij Patil

    2014-01-01

    Full Text Available Aims and Objective: The present study was undertaken to compare the results of various autogeneous tissues temporalis fascia, tragal perichondrium, and fascia lata as graft materials for the type 1 tympanoplasty. Materials and Methods: A total of 120 cases with large, subtotal and total perforation were considered in the study. Of the 120 cases, temporalis fascia graft was used in 60 cases (Group-I, tragal perichondrium graft in 40 cases (Group-II, and fascia lata graft in 20 cases (Group-III. The results were evaluated in the form of rate of graft success, hearing gain, and mean residual air-bone gap with respect to the graft materials. Results and Observation: A nonsignificant association was observed between the groups, that is, temporalis fascia (Group-I, tragal perichondrium (Group-II, and fascia lata (Group-III and the graft uptake. (P = 0.96 > 0.05 and air bone closure (χ2 = 2.908, P = 0.059 > 0.05. Conclusion: The graft take-up rate and Hearing improvement are similar for the different graft materials used. Size of the perforation doesn′t significantly influence the success rate of tympanoplasty as per our study. Normal translucent appearance of neotympanum in the postoperative period was seen only with temporalis fascia, while in tragal perichondrial and fascia lata grafts the neotympanum was whitish, thicker, and translucent to opaque.

  13. Smoothed Particle Hydrodynamics simulations of the core-degenerate scenario for Type Ia supernovae

    CERN Document Server

    Aznar-Siguán, G; Lorén-Aguilar, P; Soker, N; Kashi, A

    2015-01-01

    The core-degenerate (CD) scenario for type Ia supernovae (SN Ia) involves the merger of the hot core of an asymptotic giant branch (AGB) star and a white dwarf, and might contribute a non-negligible fraction of all thermonuclear supernovae. Despite its potential interest, very few studies, and based on only crude simplifications, have been devoted to investigate this possible scenario, compared with the large efforts invested to study some other scenarios. Here we perform the first three-dimensional simulations of the merger phase, and find that this process can lead to the formation of a massive white dwarf, as required by this scenario. We consider two situations, according to the mass of the circumbinary disk formed around the system during the final stages of the common envelope phase. If the disk is massive enough, the stars merge on a highly eccentric orbit. Otherwise, the merger occurs after the circumbinary disk has been ejected and gravitational wave radiation has brought the stars close to the Roche...

  14. Antitumor Activity of Alloy and Core-Shell-Type Bimetallic AgAu Nanoparticles

    Science.gov (United States)

    Shmarakov, Igor; Mukha, Iuliia; Vityuk, Nadiia; Borschovetska, Vira; Zhyshchynska, Nelya; Grodzyuk, Galyna; Eremenko, Anna

    2017-05-01

    Nanoparticles (NPs) of noble metals, namely gold and silver, remain promising anticancer agents capable of enhancing current surgery- and chemotherapeutic-based approaches in cancer treatment. Bimetallic AgAu composition can be used as a more effective agent due to the synergetic effect. Among the physicochemical parameters affecting gold and silver nanoparticle biological activity, a primary concern relates to their size, shape, composition, charge, etc. However, the impact of metal components/composition as well as metal topological distribution within NPs is incompletely characterized and remains to be further elucidated and clarified. In the present work, we tested a series of colloidal solutions of AgAu NPs of alloy and core-shell type for an antitumor activity depending on metal molar ratios (Ag:Au = 1:1; 1:3; 3:1) and topological distribution of gold and silver within NPs (AucoreAgshell; AgcoreAushell). The efficacy at which an administration of the gold and silver NPs inhibits mouse Lewis lung carcinoma (LLC) growth in vivo was compared. The data suggest that in vivo antitumor activity of the studied NPs strongly depends on gold and silver interaction arising from their ordered topological distribution. NPs with Ag core covered by Au shell were the most effective among the NPs tested towards LLC tumor growth and metastasizing inhibition. Our data show that among the NPs tested in this study, AgcoreAushell NPs may serve as a suitable anticancerous prototype.

  15. Torque Characteristic Analysis of a Transverse Flux Motor Using a Combined-Type Stator Core

    Directory of Open Access Journals (Sweden)

    Xiaobao Yang

    2016-11-01

    Full Text Available An external rotor transverse flux motor using a combined-type stator core is proposed for a direct drive application in this paper. The stator core is combined by two kinds of components that can both be manufactured conveniently by generic laminated silicon steel used in traditional motors. The motor benefits from the predominance of low manufacturing cost and low iron loss by using a silicon-steel sheet. Firstly, the basic structure and operation principles of the proposed motor are introduced. Secondly, the expressions of the electromagnetic torque and the cogging torque are deduced by theoretical analysis. Thirdly, the basic characteristics such as permanent magnet flux linkage, no-load back electromotive force, cogging torque and electromagnetic torque are analyzed by a three-dimensional finite element method (3D FEM. Then, the influence of structure parameters on the torque density is investigated, which provides a useful foundation for optimum design of the novel motor. Finally, the torque density of the proposed motor is calculated and discussed, and the result shows that the proposed motor in this paper can provide considerable torque density by using few permanent magnets.

  16. The core-degenerate scenario for the progenitors of type Ia supernovae

    CERN Document Server

    Wang, Bo; Zuo, Zhaoyu; Li, Yinbi; Luo, Xia; Zhang, Jujia; Liu, Dongdong; Wu, Chengyuan

    2016-01-01

    The origin of the progenitors of type Ia supernovae (SNe Ia) is still uncertain. The core-degenerate (CD) scenario has been proposed as an alternative way for the production of SNe Ia. In this scenario, SNe Ia are formed at the final stage of common-envelope evolution from a merger of a carbon-oxygen white dwarf (CO WD) with the CO core of an asymptotic giant branch companion. However, the birthrates of SNe Ia from this scenario are still not well determined. In this work, we performed a detailed investigation on the CD scenario based on a binary population synthesis approach. The SN Ia delay times from this scenario are basically in the range of 90Myr-2500Myr, mainly contributing to the observed SNe Ia with short and intermediate delay times although this scenario can also produce some old SNe Ia. Meanwhile, our work indicates that the Galactic birthrates of SNe Ia from this scenario are no more than 20% of total SNe Ia due to more careful treatment of mass transfer. Although the SN Ia birthrates in the pres...

  17. Cost-Optimal Design of a 3-Phase Core Type Transformer by Gradient Search Technique

    Science.gov (United States)

    Basak, R.; Das, A.; Sensarma, A. K.; Sanyal, A. N.

    2014-04-01

    3-phase core type transformers are extensively used as power and distribution transformers in power system and their cost is a sizable proportion of the total system cost. Therefore they should be designed cost-optimally. The design methodology for reaching cost-optimality has been discussed in details by authors like Ramamoorty. It has also been discussed in brief in some of the text-books of electrical design. The paper gives a method for optimizing design, in presence of constraints specified by the customer and the regulatory authorities, through gradient search technique. The starting point has been chosen within the allowable parameter space the steepest decent path has been followed for convergence. The step length has been judiciously chosen and the program has been maneuvered to avoid local minimal points. The method appears to be best as its convergence is quickest amongst different optimizing techniques.

  18. Long Wavelength Plasmonic Absorption Enhancement in Silicon Using Optical Lithography Compatible Core-Shell-Type Nanowires

    Directory of Open Access Journals (Sweden)

    Mohammed Shahriar Sabuktagin

    2014-01-01

    Full Text Available Plasmonic properties of rectangular core-shell type nanowires embedded in thin film silicon solar cell structure were characterized using FDTD simulations. Plasmon resonance of these nanowires showed tunability from  nm. However this absorption was significantly smaller than the Ohmic loss in the silver shell due to very low near-bandgap absorption properties of silicon. Prospect of improving enhanced absorption in silicon to Ohmic loss ratio by utilizing dual capability of these nanowires in boosting impurity photovoltaic effect and efficient extraction of the photogenerated carriers was discussed. Our results indicate that high volume fabrication capacity of optical lithography techniques can be utilized for plasmonic absorption enhancement in thin film silicon solar cells over the entire long wavelength range of solar radiation.

  19. The search for ideal hernia repair; mesh materials and types.

    Science.gov (United States)

    Bilsel, Yilmaz; Abci, Ilker

    2012-01-01

    Hernia surgery continues to draw the attention of surgeons, patients, and the industry. This strong interest has driven the establishment of professional medical societies with the sole purpose of furthering the understanding of hernias and hernia repair. In the more than 100 years of development, industry has played a major role in advancing the technology to perfect the performance of hernia repair with the hope of establishing the "best" technique and its associated technology. However, with the development of newer prosthetics and approaches to hernia repair, many surgeons do not fully understand the properties of the available prosthetics. The goal of this review is to highlight the different types of meshes in an effort to clarify to surgeons what types of materials are available to them and how to select an appropriate one for a given case.

  20. Superconductivity between standard types: Multiband versus single-band materials

    Energy Technology Data Exchange (ETDEWEB)

    Vagov, A.; Shanenko, A. A.; Milošević, M. V.; Axt, V. M.; Vinokur, V. M.; Aguiar, J. Albino; Peeters, F. M.

    2016-05-06

    In the nearest vicinity of the critical temperature, types I and II of conventional single-band superconductors interchange at the Ginzburg-Landau parameter κ = 1/√2. At lower temperatures this point unfolds into a narrow but finite interval of κ’s, shaping an intertype (transitional) domain in the (κ,T ) plane. In the present work, based on the extended Ginzburg-Landau formalism, we show that the same picture of the two standard types with the transitional domain in between applies also to multiband superconductors. However, the intertype domain notably widens in the presence of multiple bands and can become extremely large when the system has a significant disparity between the band parameters. It is concluded that many multiband superconductors, such as recently discovered borides and iron-based materials, can belong to the intertype regime.

  1. Digestive ripening: a synthetic method par excellence for core-shell, alloy, and composite nanostructured materials

    Indian Academy of Sciences (India)

    Srilakshmi P Bhaskar; Balaji R Jagirdar

    2012-11-01

    The solvated metal atom dispersion (SMAD) method has been used for the synthesis of colloids of metal nanoparticles. It is a top-down approach involving condensation of metal atoms in low temperature solvent matrices in a SMADreactor maintained at 77 K.Warming of the matrix results in a slurry ofmetal atoms that interact with one another to form particles that grow in size. The organic solvent solvates the particles and acts as a weak capping agent to halt/slow down the growth process to a certain extent. This as-prepared colloid consists of metal nanoparticles that are quite polydisperse. In a process termed as digestive ripening, addition of a capping agent to the as-prepared colloid which is polydisperse renders it highly monodisperse either under ambient or thermal conditions. In this, as yet not well-understood process, smaller particles grow and the larger ones diminish in size until the system attains uniformity in size and a dynamic equilibrium is established. Using the SMAD method in combination with digestive ripening process, highly monodisperse metal, core-shell, alloy, and composite nanoparticles have been synthesized. This article is a review of our contributions together with some literature reports on this methodology to realize various nanostructured materials.

  2. The fatigue strength of graphite and carbon materials for HTTR core components

    Energy Technology Data Exchange (ETDEWEB)

    Eto, Motokuni [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Arai, Taketoshi; Konishi, Takashi

    1998-03-01

    Room temperature fatigue tests were carried out on graphite and carbon materials, which are used for the components in the core region of the HTTR, in the applied stress condition that R (={sigma} min / {sigma} max)=-3, -1, 0 (PGX graphite), =-1, 0 (ASR-ORB carbon) and =-1 (IG-11 graphite). The data were analyzed by Price`s method, homologous stress method and P-T-S diagram method to investigate which is the most appropriate to derive design S-N curves. Fatigue tests were also carried out at 980degC in vacuo on IG-11 graphite to clarify the effect of temperature on its fatigue strength. The results indicated: (1) Price`s method was the most appropriate to analyze the data for a design S-N curve. (2) Fatigue strength decreased with decreasing R-value, with the less pronounced tendency for ASR-ORB. (3) Design S-N curves were obtained on PGX and ASR-ORB on the basis of the data analyzed by Price`s method. (4) Fatigue strength of IG-11 at 980degC appeared to be almost the same as that for the room temperature fatigue strength, if the applied stress was normalized to the mean tensile strength at room temperature in vacuo. (author)

  3. Nonlinear Thermo-mechanical Finite Element Analysis of Polymer Foam Cored Sandwich Structures including Geometrical and Material Nonlinearity

    DEFF Research Database (Denmark)

    Palleti, Hara Naga Krishna Teja; Thomsen, Ole Thybo; Taher, Siavash Talebi;

    In this paper, polymer foam cored sandwich structures with fibre reinforced composite face sheets subjected to combined mechanical and thermal loads will be analysed using the commercial FE code ABAQUS® incorporating both material and geometrical nonlinearity. Large displacements and rotations ar...... are included in the analysis. The full nonlinear stress-strain curves up to failure will be considered for the polymer foams at different temperatures to study the effect of material nonlinearity in detail....

  4. The Synthesis of a Core-Shell Photocatalyst Material YF3:Ho3+@TiO2 and Investigation of Its Photocatalytic Properties

    Directory of Open Access Journals (Sweden)

    Xuan Xu

    2017-03-01

    Full Text Available In this paper, YF3:Ho3+@TiO2 core-shell nanomaterials were prepared by hydrolysis of tetra-n-butyl titanate (TBOT using polyvinylpyrrolidone K-30 (PVP as the coupling agent. Characterization methods including X-ray diffraction (XRD, transmission electron microscopy (TEM, energy-dispersive X-ray spectroscopy (EDS under TEM, X-ray photoelectron spectroscopy (XPS, fluorescence spectrometry, ultraviolet-visible diffuse reflectance spectroscopy, and electron spin resonance (ESR were used to characterize the properties and working mechanism of the prepared photocatalyst material. They indicated that the core phase YF3 nanoparticles were successfully coated with a TiO2 shell and the length of the composite was roughly 100 nm. The Ho3+ single-doped YF3:Ho3+@TiO2 displayed strong visible absorption peaks with wavelengths of 450, 537, and 644 nm, respectively. By selecting these three peaks as excitation wavelengths, we could observe 288 nm (5D4→5I8 ultraviolet emission, which confirmed that there was indeed an energy transfer from YF3:Ho3+ to anatase TiO2. In addition, this paper investigated the influences of different TBOT dosages on photocatalysis performance of the as-prepared photocatalyst material. Results showed that the YF3:Ho3+@TiO2 core-shell nanomaterial was an advanced visible-light-driven catalyst, which decomposed approximately 67% of rhodamine b (RhB and 34.6% of phenol after 10 h of photocatalysis reaction. Compared with the blank experiment, the photocatalysis efficiency was significantly improved. Finally, the visible-light-responsive photocatalytic mechanism of YF3:Ho3+@TiO2 core-shell materials and the influencing factors of photocatalytic degradation were investigated to study the apparent kinetics, which provides a theoretical basis for improving the structural design and functions of this new type of catalytic material.

  5. The Synthesis of a Core-Shell Photocatalyst Material YF3:Ho3+@TiO2 and Investigation of Its Photocatalytic Properties

    Science.gov (United States)

    Xu, Xuan; Zhou, Shiyu; Long, Jun; Wu, Tianhu; Fan, Zihong

    2017-01-01

    In this paper, YF3:Ho3+@TiO2 core-shell nanomaterials were prepared by hydrolysis of tetra-n-butyl titanate (TBOT) using polyvinylpyrrolidone K-30 (PVP) as the coupling agent. Characterization methods including X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) under TEM, X-ray photoelectron spectroscopy (XPS), fluorescence spectrometry, ultraviolet-visible diffuse reflectance spectroscopy, and electron spin resonance (ESR) were used to characterize the properties and working mechanism of the prepared photocatalyst material. They indicated that the core phase YF3 nanoparticles were successfully coated with a TiO2 shell and the length of the composite was roughly 100 nm. The Ho3+ single-doped YF3:Ho3+@TiO2 displayed strong visible absorption peaks with wavelengths of 450, 537, and 644 nm, respectively. By selecting these three peaks as excitation wavelengths, we could observe 288 nm (5D4→5I8) ultraviolet emission, which confirmed that there was indeed an energy transfer from YF3:Ho3+ to anatase TiO2. In addition, this paper investigated the influences of different TBOT dosages on photocatalysis performance of the as-prepared photocatalyst material. Results showed that the YF3:Ho3+@TiO2 core-shell nanomaterial was an advanced visible-light-driven catalyst, which decomposed approximately 67% of rhodamine b (RhB) and 34.6% of phenol after 10 h of photocatalysis reaction. Compared with the blank experiment, the photocatalysis efficiency was significantly improved. Finally, the visible-light-responsive photocatalytic mechanism of YF3:Ho3+@TiO2 core-shell materials and the influencing factors of photocatalytic degradation were investigated to study the apparent kinetics, which provides a theoretical basis for improving the structural design and functions of this new type of catalytic material. PMID:28772662

  6. A novel hybrid material: an inorganic silica aerogel core encapsulated with a tunable organic alginate aerogel layer

    OpenAIRE

    Ülker, Zeynep; Erkey, Can

    2014-01-01

    A novel layered material consisting of a silica aerogel core encapsulated by an alginate aerogel layer was developed. The components of the hybrid aerogel had the high surface area and high porosity of pure aerogels which should lead to development of new layered systems for a wide variety of applications.

  7. Stored Energy and Quality Factor of Spherical Wave Functions–in Relation to Spherical Antennas With Material Cores

    DEFF Research Database (Denmark)

    Hansen, Troels V.; Kim, Oleksiy S.; Breinbjerg, Olav

    2012-01-01

    We present closed-form expressions for central properties of spherical wave functions of arbitrary order in relation to arbitrarily sized spherical antennas with lossless solid material cores. These properties are the electric or magnetic spherical surface current distribution radiating a spherical...

  8. Comparative evaluation of shear bond strength of three resin based dual-cure core build-up materials: An In-vitro study

    Directory of Open Access Journals (Sweden)

    Gaurav Jain

    2015-01-01

    Full Text Available Aim: The in-vitro study compared the shear bond strength (SBS of three recently introduced dual-cure resin based core build-up materials namely ParaCore, FluoroCore, and MultiCore. Materials and Methods: One hundred twenty extracted permanent human mandibular molar teeth were taken and sectioned horizontally beneath the dentinoenamel junction to expose the coronal dentin. The specimens obtained were divided into three main groups based on the materials used and then further divided into four sub-groups based on time interval with ten samples each. The dentin surface was treated with the respective adhesives of the groups and then bulk filled with core build-up materials. The attained samples were than subjected to shear loading in Instron Universal Testing Machine. The data were tabulated and statistically analyzed using analysis of variance (ANOVA, Tukey′s HSD, and Levene′s test. Results: The mean SBS was highest in MultiCore at all time periods as compared to FluoroCore and ParaCore and was also higher at 48 h thermocycling in all three groups studied. Conclusion: MultiCore dual-cure resin based core build-up material showed the highest mean SBS as compared to FluoroCore and ParaCore. SBS was not negatively affected by thermocycling.

  9. Clinical features and ryanodine receptor type 1 gene mutation analysis in a Chinese family with central core disease.

    Science.gov (United States)

    Chang, Xingzhi; Jin, Yiwen; Zhao, Haijuan; Huang, Qionghui; Wang, Jingmin; Yuan, Yun; Han, Ying; Qin, Jiong

    2013-03-01

    Central core disease is a rare inherited neuromuscular disorder caused by mutations in ryanodine receptor type 1 gene. The clinical phenotype of the disease is highly variable. We report a Chinese pedigree with central core disease confirmed by the gene sequencing. All 3 patients in the family presented with mild proximal limb weakness. The serum level of creatine kinase was normal, and electromyography suggested myogenic changes. The histologic analysis of muscle biopsy showed identical central core lesions in almost all of the muscle fibers in the index case. Exon 90-106 in the C-terminal domain of the ryanodine receptor type 1 gene was amplified using polymerase chain reaction. One heterozygous missense mutation G14678A (Arg4893Gln) in exon 102 was identified in all 3 patients. This is the first report of a familial case of central core disease confirmed by molecular study in mainland China.

  10. Research activity with different types of scintillation materials

    Science.gov (United States)

    Brinkmann, K.-T.; Borisevich, A.; Diehl, S.; Dormenev, V.; Houzvicka, J.; Korjik, M.; Novotny, R. W.; Zaunick, H.-G.; Zimmermann, S.

    2016-10-01

    Nowadays there is a growing interest and demand in the development of new types of scintillation materials for experimental high energy physics. Future detector developments will focus on cheap, fast, and radiation hard materials, especially for application in collider experiments. The most recent results obtained by the Giessen group in close cooperation with colleagues from different institutes will be presented. The new start of the mass production of high quality lead tungstate crystals (PbWO4, PWO) for electromagnetic calorimetry was started by the company CRYTUR (Turnov, Czech Republic). We will present a detailed progress report on the research program of lead tungstate performed in the last two years. The latest results in the development of LuAG:Ce, YAG:Ce and LYSO:Ce inorganic fibers, grown by the micro pulling down method and cut with the heated wire technique as well as new glass ceramics material BaO*2SiO2 (DSB) doped by Ce and Gd will be presented. In addition, different samples of the organic plastic scintillator EJ-260 produced by the company Eljen Technology (Sweetwater, USA) have been characterized. The study has focused on the change of performance after irradiation with 150 MeV protons up to an integral fluence of 5-1013 protons/cm2 as well as with a strong 60Co gamma-source accumulating an integral dose of 100 Gy.

  11. Materials design data for reduced activation martensitic steel type EUROFER

    Science.gov (United States)

    Tavassoli, A.-A. F.; Alamo, A.; Bedel, L.; Forest, L.; Gentzbittel, J.-M.; Rensman, J.-W.; Diegele, E.; Lindau, R.; Schirra, M.; Schmitt, R.; Schneider, H. C.; Petersen, C.; Lancha, A.-M.; Fernandez, P.; Filacchioni, G.; Maday, M. F.; Mergia, K.; Boukos, N.; Baluc; Spätig, P.; Alves, E.; Lucon, E.

    2004-08-01

    Materials design limits derived so far from the data generated in Europe for the reduced activation ferritic/martensitic (RAFM) steel type Eurofer are presented. These data address the short-term needs of the ITER Test Blanket Modules and a DEMOnstration fusion reactor. Products tested include plates, bars, tubes, TIG and EB welds, as well as powder consolidated blocks and solid-solid HIP joints. Effects of thermal ageing and low dose neutron irradiation are also included. Results are sorted and screened according to design code requirements before being introduced in reference databases. From the physical properties databases, variations of magnetic properties, modulus of elasticity, density, thermal conductivity, thermal diffusivity, specific heat, mean and instantaneous linear coefficients of thermal expansion versus temperature are derived. From the tensile and creep properties databases design allowable stresses are derived. From the instrumented Charpy impact and fracture toughness databases, ductile to brittle transition temperature, toughness and behavior of materials in different fracture modes are evaluated. From the fatigue database, total strain range versus number of cycles to failure curves are plotted and used to derive fatigue design curves. Cyclic curves are also derived and compared with monotonic hardening curves. Finally, irradiated and aged materials data are compared to ensure that the safety margins incorporated in unirradiated design limits are not exceeded.

  12. Microwave-assisted synthesis of water-dispersed CdTe/CdSe core/shell type II quantum dots

    OpenAIRE

    Sai Li-Man; Kong Xiang Yang

    2011-01-01

    Abstract A facile synthesis of mercaptanacid-capped CdTe/CdSe (core/shell) type II quantum dots in aqueous solution by means of a microwave-assisted approach is reported. The results of X-ray diffraction and high-resolution transmission electron microscopy revealed that the as-prepared CdTe/CdSe quantum dots had a core/shell structure with high crystallinity. The core/shell quantum dots exhibit tunable fluorescence emissions by controlling the thickness of the CdSe shell. The photoluminescent...

  13. Diagnostic value of fine needle aspiration and core needle biopsy in special types of breast cancer.

    Science.gov (United States)

    Ohashi, Ryuji; Matsubara, Miyuki; Watarai, Yasuhiko; Yanagihara, Keiko; Yamashita, Koji; Tsuchiya, Shin-Ichi; Takei, Hiroyuki; Naito, Zenya

    2016-07-01

    Although fine needle aspiration (FNA) biopsy is an established tool to assess breast lesions, there has been a trend toward using core needle biopsy (CNB) instead. The aim of this study was to compare the diagnostic accuracy of FNA and CNB in special types of breast cancer. A retrospective review of diagnostic results of pre-operatively performed FNA or CNB, or a combination of the two, was conducted. The cases include histologically proven invasive ductal carcinoma of no special type (NST n = 159), invasive lobular carcinoma (ILC n = 65), mucinous carcinoma (MUC n = 51), and apocrine carcinoma (APO n = 25). The absolute diagnostic sensitivity of FNA to detect malignancy in ILC and APO patients was inferior to that of NST patients (p < 0.001 for ILC and APO). Within each cancer type, the sensitivity of CNB was higher than that of FNA in the ILC and APO patients (p < 0.001 and p < 0.05, respectively). As for NST and MUC patients, FNA and CNB had equivalent sensitivity. The sensitivity of FNA alone significantly improved when combined with CNB in NST, ILC and APO patients (p < 0.05, p < 0.001, and p < 0.05, respectively). Our results suggest that FNA has less diagnostic accuracy than CNB for ILC and APO; thus, the use of CNB should be encouraged when these types of cancer are clinically suspected or when the initial FNA is inconclusive.

  14. High performance of SDC and GDC core shell type composite electrolytes using methane as a fuel for low temperature SOFC

    Directory of Open Access Journals (Sweden)

    Muneeb Irshad

    2016-02-01

    Full Text Available Nanocomposites Samarium doped Ceria (SDC, Gadolinium doped Ceria (GDC, core shell SDC amorphous Na2CO3 (SDCC and GDC amorphous Na2CO3 (GDCC were synthesized using co-precipitation method and then compared to obtain better solid oxide electrolytes materials for low temperature Solid Oxide Fuel Cell (SOFCs. The comparison is done in terms of structure, crystallanity, thermal stability, conductivity and cell performance. In present work, XRD analysis confirmed proper doping of Sm and Gd in both single phase (SDC, GDC and dual phase core shell (SDCC, GDCC electrolyte materials. EDX analysis validated the presence of Sm and Gd in both single and dual phase electrolyte materials; also confirming the presence of amorphous Na2CO3 in SDCC and GDCC. From TGA analysis a steep weight loss is observed in case of SDCC and GDCC when temperature rises above 725 °C while SDC and GDC do not show any loss. The ionic conductivity and cell performance of single phase SDC and GDC nanocomposite were compared with core shell GDC/amorphous Na2CO3 and SDC/ amorphous Na2CO3 nanocomposites using methane fuel. It is observed that dual phase core shell electrolytes materials (SDCC, GDCC show better performance in low temperature range than their corresponding single phase electrolyte materials (SDC, GDC with methane fuel.

  15. High performance of SDC and GDC core shell type composite electrolytes using methane as a fuel for low temperature SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Irshad, Muneeb; Siraj, Khurram, E-mail: razahussaini786@gmail.com, E-mail: khurram.uet@gmail.com; Javed, Fayyaz; Ahsan, Muhammad; Rafique, Muhammad Shahid [Department of Physics, University of Engineering and Technology, Lahore (Pakistan); Raza, Rizwan, E-mail: razahussaini786@gmail.com, E-mail: khurram.uet@gmail.com [Department of Physics, COMSATS Institute of Information Technology, Lahore (Pakistan); Shakir, Imran [Deanship of scientific research, College of Engineering, PO Box 800, King Saud University, Riyadh 11421 (Saudi Arabia)

    2016-02-15

    Nanocomposites Samarium doped Ceria (SDC), Gadolinium doped Ceria (GDC), core shell SDC amorphous Na{sub 2}CO{sub 3} (SDCC) and GDC amorphous Na{sub 2}CO{sub 3} (GDCC) were synthesized using co-precipitation method and then compared to obtain better solid oxide electrolytes materials for low temperature Solid Oxide Fuel Cell (SOFCs). The comparison is done in terms of structure, crystallanity, thermal stability, conductivity and cell performance. In present work, XRD analysis confirmed proper doping of Sm and Gd in both single phase (SDC, GDC) and dual phase core shell (SDCC, GDCC) electrolyte materials. EDX analysis validated the presence of Sm and Gd in both single and dual phase electrolyte materials; also confirming the presence of amorphous Na{sub 2}CO{sub 3} in SDCC and GDCC. From TGA analysis a steep weight loss is observed in case of SDCC and GDCC when temperature rises above 725 °C while SDC and GDC do not show any loss. The ionic conductivity and cell performance of single phase SDC and GDC nanocomposite were compared with core shell GDC/amorphous Na{sub 2}CO{sub 3} and SDC/ amorphous Na{sub 2}CO{sub 3} nanocomposites using methane fuel. It is observed that dual phase core shell electrolytes materials (SDCC, GDCC) show better performance in low temperature range than their corresponding single phase electrolyte materials (SDC, GDC) with methane fuel.

  16. Nuclear structure and the fate of core collapse (Type II) supernova

    Energy Technology Data Exchange (ETDEWEB)

    Gai, Moshe [LNS at Avery Point, University of Connecticut, Groton, CT 06340-6097 (United States); Wright Lab, Dept. of Physics, Yale University, New Haven, CT 06520-8124 (United States)

    2014-08-15

    For a long time Gerry Brown and his collaborator Hans Bethe considered the question of the final fate of a core collapse (Type II) supernova. Recalling ideas from nuclear structure on Kaon condensate and a soft equation of state of the dense nuclear matter they concluded that progenitor stars with mass as low as 17–18M{sub ⊙} (including supernova 1987A) could collapse to a small mass black hole with a mass just beyond 1.5M{sub ⊙}, the upper bound they derive for a neutron star. We discuss another nuclear structure effect that determines the carbon to oxygen ratio (C/O) at the end of helium burning. This ratio also determines the fate of a Type II supernova with a carbon rich progenitor star producing a neutron star and oxygen rich collapsing to a black hole. While the C/O ratio is one of the most important nuclear inputs to stellar evolution it is still not known with sufficient accuracy. We discuss future efforts to measure with gamma-beam and TPC detector of the {sup 12}C(α,γ){sup 16}O reaction that determines the C/O ratio in stellar helium burning.

  17. Nuclear Structure and the Fate of Core Collapse (Type II) Supernova

    CERN Document Server

    Gai, Moshe

    2014-01-01

    For a long time Gerry Brown and his collaborator Hans Bethe considered the question of the final fate of a core collapse (Type II) supernova. Recalling ideas from nuclear structure on Kaon condensate and a soft equation of state of the dense nuclear matter they concluded that progenitor stars with mass as low a 17-18M$_\\odot$ (including supernova 1987A) could collapse to a small mass black hole with a mass just beyond 1.5M$_\\odot$, the upper bound they derive for a neutron star. We discuss another nuclear structure effect that determines the carbon to oxygen ratio (C/O) at the end of helium burning. This ratio also determines the fate of a Type II supernova with a carbon rich progenitor star producing a neutron star and oxygen rich collapsing to a black hole. While the C/O ratio is one of the most important nuclear input to stellar evolution it is still not known with sufficient accuracy. We discuss future efforts to measure with gamma-beam and TPC detector the 12C(a,g)16O reaction that determines the C/O rat...

  18. 46 CFR 160.077-13 - Materials-Type I and Commercial Hybrid PFD.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Materials-Type I and Commercial Hybrid PFD. 160.077-13... Flotation Devices § 160.077-13 Materials—Type I and Commercial Hybrid PFD. (a) General. All commercial... material on each reversible side, if any. The material must be Type I material that is approved...

  19. Standard practice for radiologic examination of flat panel composites and sandwich core materials used in aerospace applications

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This practice is intended to be used as a supplement to Practices E 1742, E 1255, and E 2033. 1.2 This practice describes procedures for radiologic examination of flat panel composites and sandwich core materials made entirely or in part from fiber-reinforced polymer matrix composites. Radiologic examination is: a) radiographic (RT) with film, b) Computed Radiography (CR) with Imaging Plate, c) Digital Radiology (DR) with Digital Detector Array’s (DDA), and d) Radioscopic (RTR) Real Time Radiology with a detection system such as an Image Intensifier. The composite materials under consideration typically contain continuous high modulus fibers (> 20 GPa), such as those listed in 1.4. 1.3 This practice describes established radiological examination methods that are currently used by industry that have demonstrated utility in quality assurance of flat panel composites and sandwich core materials during product process design and optimization, process control, after manufacture inspection, in service exami...

  20. Comparative evaluation of shear bond strength of three resin based dual-cure core build-up materials: An In-vitro study.

    Science.gov (United States)

    Jain, Gaurav; Narad, Aditi; Boruah, Lalit C; Rajkumar, Balakrishnan

    2015-01-01

    The in-vitro study compared the shear bond strength (SBS) of three recently introduced dual-cure resin based core build-up materials namely ParaCore, FluoroCore, and MultiCore. One hundred twenty extracted permanent human mandibular molar teeth were taken and sectioned horizontally beneath the dentinoenamel junction to expose the coronal dentin. The specimens obtained were divided into three main groups based on the materials used and then further divided into four sub-groups based on time interval with ten samples each. The dentin surface was treated with the respective adhesives of the groups and then bulk filled with core build-up materials. The attained samples were than subjected to shear loading in Instron Universal Testing Machine. The data were tabulated and statistically analyzed using analysis of variance (ANOVA), Tukey's HSD, and Levene's test. The mean SBS was highest in MultiCore at all time periods as compared to FluoroCore and ParaCore and was also higher at 48 h thermocycling in all three groups studied. MultiCore dual-cure resin based core build-up material showed the highest mean SBS as compared to FluoroCore and ParaCore. SBS was not negatively affected by thermocycling.

  1. Fine Distributed Moderating Material with Improved Thermal Stability Applied to Enhance the Feedback Effects in SFR Cores

    Directory of Open Access Journals (Sweden)

    Bruno Merk

    2013-01-01

    Full Text Available The use of fine distributed moderating material to enhance the feedback effects and to reduce the sodium void effect in sodium-cooled fast reactor cores is described. The influence of the moderating material on the fuel assembly geometry, the neutron spectrum, the feedback effects, the power and burnup distribution, and the transmutation performance is given. An overview on possible materials is provided and the relationship between hydrogen content and thermal stability is described. A solution for the problem of the limited thermal stability of primarily proposed hydrogen-bearing moderating material ZrH1.6 is developed by the use of yttrium-mono-hydride. The similarity in the effects reached by ZrH and YH is demonstrated by comparison calculations. The topic is closed by an overview on material properties, manufacturing issues, experience in fast reactors, and a comparison of raw material costs.

  2. A core-shell structured nanocomposite material for detection, adsorption and removal of Hg(II) ions in water.

    Science.gov (United States)

    Li, Le; Tang, Shuangyang; Ding, Dexin; Hu, Nan; Yang, Shengyuan; He, Shuya; Wang, Yongdong; Tan, Yan; Sun, Jing

    2012-11-01

    In this paper, a core-shell structured nanocomposite material was prepared for the detection, adsorption and removal of Hg(ll) ions in aqueous solution. The core was made from Fe3O4 nanoparticles with superparamagnetic behavior and the outer shell was made from amorphous silica modified with pyrene-based sensing-probes. The material could detect and adsorb Hg(II) ions in aqueous solution due to its surface being modified with pyrene-based sensing-probes, and could easily be removed from the solution by magnetic force because of its core being made from magnetic Fe3O4 nanoparticles. This multifunctional core-shell structure was confirmed and characterized by TEM, IR spectra, TGA, XRD and N2 adsorption/desorption isotherms. Experiments were conducted on its functions of detection, adsorption and removal of Hg(II) ions in aqueous solution. The experimental results showed that this composite material had high sensitivity and unique selectivity to Hg(II), and that it could easily be removed from the solution.

  3. Bond strength of a calcium silicate-based sealer tested in bulk or with different main core materials.

    Science.gov (United States)

    Nagas, Emre; Cehreli, Zafer; Uyanik, Mehmet Ozgur; Durmaz, Veli

    2014-01-01

    The aim of this study was to evaluate the influence of a calcium silicate-based sealer (iRoot SP), with or without a core material, on bond strength to radicular dentin, in comparison with various contemporary root filling systems. Root canals of freshly extracted single-rooted teeth (n = 60) were instrumented using rotary instruments. The roots were randomly assigned to one of the following experimental groups: (1) a calcium silicate-based sealer without a core material (bulk-fill); (2) a calcium silicate-based sealer + gutta-percha; (3) a calcium silicate-based sealer + Resilon; (4) a methacrylate resin-based sealer (RealSeal SE) + Resilon; (5) an epoxy resin-based sealer (AH Plus) + gutta-percha, and (6) a mineral trioxide aggregate-based endodontic sealer (MTA Fillapex) + gutta-percha. Four 1-mm-thick sections were obtained from the coronal aspect of each root (n = 40 slices/group). Push-out bond strength testing was performed at a cross-head speed of 1 mm/min, and the bond strength data were analyzed statistically by one-way analysis of variance and Tukey tests (p core filling materials. When the calcium silicate-based sealer was placed in bulk, its dislocation resistance was similar to that of commonly used sealer + core root filling systems. Thus, the concept of using a calcium silicate-based sealer in bulk can be more easily advocated in clinical practice.

  4. New long-cycle small modular PWR cores using particle type burnable poisons for low boron operation

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Hoseong; Hwang, Dae Hee [Department of Nuclear Engineering, Kyung Hee University, Deogyeong-daero, GiHeung-gu, Yongin, Gyeonggi-do 446-701 (Korea, Republic of); Hong, Ser Gi, E-mail: sergihong@khu.ac.kr [Department of Nuclear Engineering, Kyung Hee University, Deogyeong-daero, GiHeung-gu, Yongin, Gyeonggi-do 446-701 (Korea, Republic of); Shin, Ho Choel [Core and Fuel Analysis Group, Korea Hydro & Nuclear Power Central Research Institute (KHNP-CRI), Daejon 305-343 (Korea, Republic of)

    2017-04-01

    Highlights: • New advanced burnable poison rods (BPR) are suggested for low boron operation in PWR. • The new SMR cores have long cycle length of ∼4.5 EFPYs with low boron concentration. • The SMR core satisfies all the design targets and constraints. - Abstract: In this paper, new small long-cycle PWR (Pressurized Water Reactor) cores for low boron concentration operation are designed by employing advanced burnable poison rods (BPRs) in which the BISO (Bi-Isotropic) particles of burnable poison are distributed in a SiC matrix. The BPRs are designed by adjusting the kernel diameter, the kernel material and the packing fraction to effectively reduce the excess reactivity in order to reduce the boron concentration in the coolant and achieve a flat change in excess reactivity over a long operational cycle. In addition, axial zoning of the BPRs was suggested to improve the core performances, and it was shown that the suggested axial zoning of BPRs considerably extends the cycle length compared to a core with no BPR axial zoning. The results of the core physics analyses showed that the cores using BPRs with a B{sub 4}C kernel have long cycle lengths of ∼4.5 EFPYs (Effective Full Power Years), small maximum CBCs (Critical Boron Concentration) lower than 370 ppm, low power peaking factors, and large shutdown margins of control element assemblies.

  5. Crust behavior and erosion rate prediction of EPR sacrificial material impinged by core melt jet

    Energy Technology Data Exchange (ETDEWEB)

    Li, Gen; Liu, Ming, E-mail: ming.liu@mail.xjtu.edu.cn; Wang, Jinshi; Chong, Daotong; Yan, Junjie

    2017-04-01

    Highlights: • A numerical code was developed to analyze melt jet-concrete interaction in the frame of MPS method. • Crust and ablated concrete layer at UO{sub 2}-ZrO{sub 2} melt and concrete interface periodically developed and collapsed. • Concrete surface temperature fluctuated around a low temperature and ablation temperature. • Concrete erosion by Fe-Zr melt jet was significantly faster than that by UO{sub 2}-ZrO{sub 2} melt jet. - Abstract: Sacrificial material is a special ferro-siliceous concrete, designed in the ex-vessel core melt stabilization system of European Pressurized water Reactor (EPR). Given a localized break of RPV lower head, the melt directly impinges onto the dry concrete in form of compact jet. The concrete erosion behavior influences the failure of melt plug, and further affects melt spreading. In this study, a numerical code was developed in the frame of Moving Particle Semi-implicit (MPS) method, to analyze the crust behavior and erosion rate of sacrificial concrete, impinged by prototypic melt jet. In validation of numerical modeling, the time-dependent erosion depth and erosion configuration matched well with the experimental data. Sensitivity study of sacrificial concrete erosion indicates that the crust and ablated concrete layer presented at UO{sub 2}-ZrO{sub 2} melt and concrete interface, whereas no crust could be found in the interaction of Fe-Zr melt with concrete. The crust went through stabilization-fracture-reformation periodic process, accompanied with accumulating and collapsing of molten concrete layer. The concrete surface temperature fluctuated around a low temperature and ablation temperature. It increased as the concrete surface layer was heated to melting, and dropped down when the cold concrete was revealed. The erosion progression was fast in the conditions of small jet diameter and large concrete inclination angle, and it was significantly faster in the erosion by metallic melt jet than by oxidic melt jet.

  6. Interstrand contact resistance and magnetization of Nb3Sn Rutherford cables with cores of different materials and widths

    NARCIS (Netherlands)

    Collings, E.W.; Sumption, M.D.; Dietderich, D.R.; Susner, M.; Krooshoop, H.J.G.; Nijhuis, A.

    2012-01-01

    Rutherford cables with cores of E-glass and S-glass woven tape and types AISI-316 and AISI-304 stainless steel (SS) ribbon were subjected to calorimetric AC loss measurement in transverse magnetic fields of amplitude 400 mT and frequencies of up to 90 mHz applied in the face-on (FO) and edge-on (EO)

  7. N,O-Type Carborane-Based Materials

    Directory of Open Access Journals (Sweden)

    José Giner Planas

    2016-05-01

    Full Text Available This review summarizes the synthesis and coordination chemistry of a series of carboranyl ligands containing N,O donors. Such carborane-based ligands are scarcely reported in the literature when compared to other heteroatom-containing donors. The synthetic routes for metal complexes of these N,O-type carborane ligands are summarized and the properties of such complexes are described in detail. Particular attention is paid to the effect that the incorporation of carboranes has into the coordination chemistry of the otherwise carbon-based ligands and the properties of such materials. The reported complexes show a variety of properties such as those used in magnetic, chiroptical, nonlinear optical, catalytic and biomedical applications.

  8. Study on preparation and microwave absorption property of the core-nanoshell composite materials doped with La.

    Science.gov (United States)

    Wei, Liqiu; Che, Ruxin; Jiang, Yijun; Yu, Bing

    2013-12-01

    Microwave absorbing material plays a great role in electromagnetic pollution controlling, electromagnetic interference shielding and stealth technology, etc. The core-nanoshell composite materials doped with La were prepared by a solid-state reaction method, which is applied to the electromagnetic wave absorption. The core is magnetic fly-ash hollow cenosphere, and the shell is the nanosized ferrite doped with La. The thermal decomposition process of the sample was investigated by thermogravimetry and differential thermal analysis. The morphology and components of the composite materials were investigated by the X-ray diffraction analysis, the microstructure was observed by scanning electron microscope and transmission electron microscope. The results of vibrating sample magnetometer analysis indicated that the exchange-coupling interaction happens between ferrite of magnetic fly-ash hollow cenosphere and nanosized ferrite coating, which caused outstanding magnetic properties. The microwave absorbing property of the sample was measured by reflectivity far field radar cross section of radar microwave absorbing material with vector network analyzer. The results indicated that the exchange-coupling interaction enhanced magnetic loss of composite materials. Therefore, in the frequency of 5 GHz, the reflection coefficient can achieve -24 dB. It is better than single material and is consistent with requirements of the microwave absorbing material at the low-frequency absorption.

  9. THERMAL UPGRADING OF 9977 RADIOACTIVE MATERIAL (RAM) TYPE B PACKAGE

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, N.; Abramczyk, G.

    2012-03-26

    The 9977 package is a radioactive material package that was originally certified to ship Heat Sources and RTG contents up to 19 watts and it is now being reviewed to significantly expand its contents in support of additional DOE missions. Thermal upgrading will be accomplished by employing stacked 3013 containers, a 3013 aluminum spacer and an external aluminum sleeve for enhanced heat transfer. The 7th Addendum to the original 9977 package Safety Basis Report describing these modifications is under review for the DOE certification. The analyses described in this paper show that this well-designed and conservatively analyzed package can be upgraded to carry contents with decay heat up to 38 watts with some simple design modifications. The Model 9977 package has been designed as a replacement for the Department of Transportation (DOT) Fissile Specification 6M package. The 9977 package is a very versatile Type B package which is certified to transport and store a wide spectrum of radioactive materials. The package was analyzed quite conservatively to increase its usefulness and store different payload configurations. Its versatility is evident from several daughter packages such as the 9978 and H1700, and several addendums where the payloads have been modified to suit the Shipper's needs without additional testing.

  10. Sectioned Core Doping Effect on Higher-Order Mode Amplification in Yb-Doped Rod-Type Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Poli, F.; Lægsgaard, Jesper; Passaro, D.

    2009-01-01

    The amplification properties of guided modes in Yb-doped rod-type photonic crystal fibers with sectioned core doping have been investigated, evaluating the doped-area radius which provides the effective suppression of both LP 11- and LP02-like modes.......The amplification properties of guided modes in Yb-doped rod-type photonic crystal fibers with sectioned core doping have been investigated, evaluating the doped-area radius which provides the effective suppression of both LP 11- and LP02-like modes....

  11. Dispersal of dense protostellar material - NH3 hot cores and outflows in Sagittarius B2

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, S.N.; Genzel, R.; Palmer, P.

    1987-05-01

    VLA observations of Sgr B2 in six ammonia transitions have uncovered two 200-K condensations with approximately 0.2 pc diameters associated with water maser sources which are similar to the Orion hot core but are more massive. Total NH3 mass of the northern source is 1000 times higher than in the Orion hot core. The hot core emission traces dense gas around newly formed massive stars, and is produced during a relatively brief stage after the star begins to heat the surrounding medium and before the dense gas is dispersed by outflow and the emergence of an expanding H II region. 36 references.

  12. Sediments at the top of Earth's core.

    Science.gov (United States)

    Buffett, B A; Garnero, E J; Jeanloz, R

    2000-11-17

    Unusual physical properties at the core-mantle boundary have been inferred from seismic and geodetic observations in recent years. We show how both types of observations can be explained by a layer of silicate sediments, which accumulate at the top of the core as Earth cools. Compaction of the sediments expels most of the liquid iron but leaves behind a small amount of core material, which is entrained in mantle convection and may account for the isotopic signatures of core material in some hot spot plumes. Extraction of light elements from the liquid core also enhances the vigor of convection in the core and may increase the power available to the geodynamo.

  13. The feasibility of small size specimens for testing of environmentally assisted cracking of irradiated materials and of materials under irradiation in reactor core

    Energy Technology Data Exchange (ETDEWEB)

    Toivonen, A.; Moilanen, P.; Pyykkoenen, M.; Taehtinen, S.; Rintamaa, R.; Saario, T. [Valtion Teknillinen Tutkimuskeskus, Espoo (Finland)

    1998-11-01

    Environmentally assisted cracking (EAC) of core materials has become an increasingly important issue of downtime and maintenance costs in nuclear power plants. Small size specimens are necessary in stress corrosion testing of irradiated materials because of difficulties in handling high dose rate materials and because of restricted availability of the materials. The drawback of using small size specimens is that in some cases they do not fulfil the requirements of the relevant testing standards. Recently VTT has developed J-R testing with irradiated and non-irradiated sub size 3 PB specimens, both in inert and in LWR environments. Also, a new materials testing system which will enable simultaneous multiple specimen testing both in laboratory conditions and in operating reactor core is under development. The new testing system will utilize Charpy and sub size 3 PB specimens. The feasibility study of the system has been carried out using different materials. Fracture resistance curves of a Cu-Zr-Cr alloy are shown to be independent of the specimen geometry and size, to some extent. Results gained from tests in simulated boiling water reactor (BWR) water are presented for sensitized SIS 2333 stainless steel. The experimental results indicate that the size of the plastic zone or stress triaxiality must be further studied although no significant effect on the environmentally assisted crack growth rate was observed. (orig.)

  14. Heat Storage Performance of the Prefabricated Hollow Core Concrete Deck Element with Integrated Microencapsulated Phase Change Material

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2012-01-01

    of thermal properties of standard concrete material and pure PCM. Consequently, the numerical models of the decks were updated with the experimentally determined thermal properties of PCM concrete after these two materials have been combined into one material. Finally, the heat storage of the decks......The paper presents the numerically calculated dynamic heat storage capacity of the prefabricated hollow core concrete deck element with and without microencapsulated phase change material (PCM). The reference deck is the ordinary deck made of standard concrete material and that is broadly used...... in many emerging buildings. The new concrete deck with microencapsulated PCM is the standard deck on which one more layer with PCM concrete was added and at the same time the latent heat storage was introduced to the construction. The challenge to simulate the performance of the new deck with PCM concrete...

  15. Liquid-crystalline hybrid materials based on [60]fullerene and bent-core structures.

    Science.gov (United States)

    Vergara, Jorge; Barberá, Joaquín; Serrano, José Luis; Ros, M Blanca; Sebastián, Nerea; de la Fuente, Rosario; López, David O; Fernández, Gustavo; Sánchez, Luis; Martín, Nazario

    2011-12-23

    What a core-ker! By the appropriate combination of promesogenic bent-core structures and the C(60)  unit, lamellar polar liquid-crystal phases were induced. The supramolecular organization of the functional fullerene-based assemblies, the temperature range of the soft phase, the stabilization of the mesophase-like order at room temperature, and the molecular switching under an electric field can be tuned, depending on the molecular structure.

  16. An X-ray and Neutron Scattering Study of the Formation of Core-Shell Type Polyoxometalates

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Panchao; Wu, Bin; Mamontov, Eugene; Daemen, Luke L.; Cheng, Yongqiang; Li, Tao; Seifert, Soenke; Hong, Kunlun; Bonnesen, Peter V.; Keum, Jong Kahk; Ramirez-Cuesta, Anibal J.

    2016-03-02

    A typical type of core-shell polyoxometalates can be obtained through the Keggin-type polyoxometalatetemplated growth of a layer of spherical shell structure of {Mo72Fe30}. Small angle X-ray scattering is used to study the structural features and stability of the core-shell structures in aqueous solutions. Timeresolved small angle X-ray scattering is applied to monitor the synthetic reactions and a three-stage formation mechanism is proposed to describe the synthesis of the core-shell polyoxometalates based on the monitoring results. New protocols have been developed by fitting the X-ray data with customed physical models, which provide more convincing, objective, and completed data interpretation. Quasielastic and inelastic neutron scattering are used to probe the dynamics of water molecules in the core-shell structures and two different types of water molecules, the confined and structured water, are observed. These water molecules play an important role in bridging core and shell structures and stabilizing the cluster structures.

  17. Preparation and characterization of core-shell battery materials for Li-ion batteries manufactured by substrate induced coagulation

    Science.gov (United States)

    Basch, Angelika; Albering, Jörg H.

    2011-03-01

    In this work Substrate Induced Coagulation (SIC) was used to coat the cathode material LiCoO2, commonly used in Li-ion batteries, with fine nano-sized particulate titania. Substrate Induced Coagulation is a self-assembled dip-coating process capable of coating different surfaces with fine particulate materials from liquid media. A SIC coating consists of thin and rinse-prove layers of solid particles. An advantage of this dip-coating method is that the method is easy and cheap and that the materials can be handled by standard lab equipment. Here, the SIC coating of titania on LiCoO2 is followed by a solid-state reaction forming new inorganic layers and a core-shell material, while keeping the content of active battery material high. This titania based coating was designed to confine the reaction of extensively delithiated (charged) LiCoO2 and the electrolyte. The core-shell materials were characterized by SEM, XPS, XRD and Rietveld analysis.

  18. Fabrication of Fe3O4@CuO core-shell from MOF based materials and its antibacterial activity

    Science.gov (United States)

    Rajabi, S. K.; Sohrabnezhad, Sh.; Ghafourian, S.

    2016-12-01

    Magnetic Fe3O4@CuO nanocomposite with a core/shell structure was successfully synthesized via direct calcinations of magnetic Fe3O4@HKUST-1 in air atmosphere. The morphology, structure, magnetic and porous properties of the as-synthesized nano composites were characterized by using scanning electron microscope (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and vibration sample magnetometer (VSM). The results showed that the nanocomposite material included a Fe3O4 core and a CuO shell. The Fe3O4@CuO core-shell can be separated easily from the medium by a small magnet. The antibacterial activity of Fe3O4-CuO core-shell was investigated against gram-positive and gram-negative bacteria. A new mechanism was proposed for inactivation of bacteria over the prepared sample. It was demonstrated that the core-shell exhibit recyclable antibacterial activity, acting as an ideal long-acting antibacterial agent.

  19. SN 2012aa: A transient between Type Ibc core-collapse and superluminous supernovae

    Science.gov (United States)

    Roy, R.; Sollerman, J.; Silverman, J. M.; Pastorello, A.; Fransson, C.; Drake, A.; Taddia, F.; Fremling, C.; Kankare, E.; Kumar, B.; Cappellaro, E.; Bose, S.; Benetti, S.; Filippenko, A. V.; Valenti, S.; Nyholm, A.; Ergon, M.; Sutaria, F.; Kumar, B.; Pandey, S. B.; Nicholl, M.; Garcia-Álvarez, D.; Tomasella, L.; Karamehmetoglu, E.; Migotto, K.

    2016-12-01

    Context. Research on supernovae (SNe) over the past decade has confirmed that there is a distinct class of events which are much more luminous (by 2 mag) than canonical core-collapse SNe (CCSNe). These events with visual peak magnitudes ≲-21 are called superluminous SNe (SLSNe). The mechanism that powers the light curves of SLSNe is still not well understood. The proposed scenarios are circumstellar interaction, the emergence of a magnetar after core collapse, or disruption of a massive star through pair production. Aims: There are a few intermediate events which have luminosities between these two classes. They are important for constraining the nature of the progenitors of these two different populations and their environments and powering mechanisms. Here we study one such object, SN 2012aa. Methods: We observed and analysed the evolution of the luminous Type Ic SN 2012aa. The event was discovered by the Lick Observatory Supernova Search in an anonymous galaxy (z ≈ 0.08). The optical photometric and spectroscopic follow-up observations were conducted over a time span of about 120 days. Results: With an absolute V-band peak of - 20 mag, the SN is an intermediate-luminosity transient between regular SNe Ibc and SLSNe. SN 2012aa also exhibits an unusual secondary bump after the maximum in its light curve. For SN 2012aa, we interpret this as a manifestation of SN-shock interaction with the circumstellar medium (CSM). If we assume a 56Ni-powered ejecta, the quasi-bolometric light curve requires roughly 1.3 M⊙ of 56Ni and an ejected mass of 14M⊙. This also implies a high kinetic energy of the explosion, 5.4 × 1051 erg. On the other hand, the unusually broad light curve along with the secondary peak indicate the possibility of interaction with CSM. The third alternative is the presence of a central engine releasing spin energy that eventually powers the light curve over a long time. The host of SN 2012aa is a star-forming Sa/Sb/Sbc galaxy. Conclusions

  20. Compressive fatigue limit of four types of dental restorative materials.

    Science.gov (United States)

    Chen, Song; Öhman, Caroline; Jefferies, Steven R; Gray, Holly; Xia, Wei; Engqvist, Håkan

    2016-08-01

    The purpose of this study was to evaluate the quasi-static compressive strength and the compressive fatigue limit of four different dental restorative materials, before and after aging in distilled water for 30 days. A conventional glass ionomer cement (Fuji IX GP; IG), a zinc-reinforced glass ionomer cement (Chemfil rock; CF), a light curable resin-reinforced glass ionomer cement (Fuji II LC; LC) and a resin-based composite (Quixfil; QF) were investigated. Cylindrical specimens (4mm in diameter and 6mm in height) were prepared according to the manufacturer׳s instructions. The compressive fatigue limit was obtained using the staircase method. Samples were tested in distilled water at 37°C, at a frequency of 10Hz with 10(5) cycles set as run-out. 17 fatigue samples were tested for each group. Two-way ANOVA and one-way ANOVA followed by Tukey׳s post-hoc test were used to analyze the results. Among the four types of materials, the resin-based composite exhibited the highest compressive strength (244±13.0MPa) and compressive fatigue limit (134±7.8MPa), followed by the light-cured resin reinforced glass ionomer cement (168±8.5MPa and 92±6.6MPa, respectively) after one day of storage in distilled water. After being stored for 30 days, all specimens showed an increase in compressive strength. Aging showed no effect on the compressive fatigue limit of the resin-based composite and the light-cured resin reinforced glass ionomer cement, however, the conventional glass ionomer cements showed a drastic decrease (37% for IG, 31% for CF) in compressive fatigue limit. In conclusion, in the present study, resin modified GIC and resin-based composite were found to have superior mechanical properties to conventional GIC.

  1. The Influence of the Material of the Transformer Core on Characteristics of the Selected DC-DC Converters

    Science.gov (United States)

    Górecki, Krzysztof; Zarębski, Janusz

    In the paper the influence of the ferromagnetic material used for the construction of the core of the impulse-transformer on the characteristics of a half-bridge converter is considered. The investigated network is described and some results of measurements are shown. On the basis of the obtained characteristics of the investigated converters some suggestions for the designers of such circuits are formulated.

  2. Effect of Er:YAG laser pretreatment on bond strength of a composite core build-up material to fiber posts.

    Science.gov (United States)

    Križnar, Igor; Jevnikar, Peter; Fidler, Aleš

    2015-02-01

    The study evaluated the micro push-out bond strength of resin material (Multicore Flow) to two types of fiber posts (FP), namely fiber-reinforced composite (FRC) Postec and Radix Fiber posts using Er:YAG laser pretreatment. FP were divided into four groups, two being control groups. Before the core build-up procedure, representative specimens from each group were chosen to determine the surface roughness (Ra) at three different areas using a contact profilometer, while after the procedure, 1.5-mm-thick discs were sectioned and the micro push-out method was used to assess the bond strength of the core build-up material to the fiber post in each group. Two-way analysis of variance was used for statistical analysis with the level of significance set at p Er:YAG laser pretreatment and to classify the failure mode after loading. The type of pretreatment (p Er:YAG laser pretreatment group was significantly lower compared to the FRC Postec posts control group (p Er:YAG laser pretreatment groups were significantly higher compared to control groups (p Er:YAG laser pretreatment at tested parameters negatively affected the bond strength of Multicore to FP and cannot be recommended as a standard procedure.

  3. Radiological decontamination strippable coatings using PVA and PVP based core-shell polymeric scintillation materials

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Ho Sang; Seo, Bum Kyoung; Lee, Kune Woo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-05-15

    Strippable coatings are innovative technologies for decontamination that effectively reduce loose contamination. These coatings are polymer mixtures, such as water-based organic polymers that are applied to a surface by paintbrush, roller or spray applicator. In this study, the core-shell composite polymer for decontamination from the surface contamination was synthesized by the method of emulsion polymerization and blends of polymers. The strippable polymer emulsion is composed of the poly(styrene-ethyl acrylate) [poly(St-EA)] composite polymer, poly(vinyl alcohol) (PVA) and polyvinylpyrrolidone (PVP). The morphology of the composite emulsion particle was core-shell structure, with polystyrene (PS) as the core and poly(ethyl acrylate) (PEA) as the shell. Core-shell polymers of styrene (St)/ethyl acrylate (EA) pair were prepared by sequential emulsion polymerization in the presence of sodium dodecyl sulfate (SDS) as an emulsifier using ammonium persulfate (APS) as an initiator. Related tests and analysis confirmed the success in synthesis of composite polymer. The products are characterized by FT-IR spectroscopy, TGA that were used, respectively, to show the structure, the thermal stability of the prepared polymer. Two-phase particles with a core-shell structure were obtained in experiments where the estimated glass transition temperature and the morphologies of emulsion particles. Decontamination factors (DF) of the strippable polymeric emulsion were evaluated with the polymer blend contents

  4. Calculation Method of Lamination Plate Types in Frame Type Core of Transformer%变压器框式铁心的片型计算方法

    Institute of Scientific and Technical Information of China (English)

    王欢; 刘光辉

    2012-01-01

    The calculation method of types of limb,side limb and yoke in three-phase five-limb four-frame core is presented.%介绍了三相五柱四框式铁心心柱、旁柱及铁轭等片型的计算方法。

  5. Protein encapsulated core-shell structured particles prepared by coaxial electrospraying: investigation on material and processing variables.

    Science.gov (United States)

    Zamani, Maedeh; Prabhakaran, Molamma P; Thian, Eng San; Ramakrishna, Seeram

    2014-10-01

    Biodegradable polymeric particles have been extensively investigated for controlled drug delivery of various therapeutic agents. 'Coaxial' electrospraying was successfully employed in this study, to fabricate core-shell PLGA particles containing bovine serum albumin (BSA) as the model protein, and the results were also compared to particles prepared by 'emulsion' electrospraying. Two different molecular weights of PLGA were employed to encapsulate the protein. Solution properties and processing parameters were found to influence the morphology of the core-shell particles. Depending on the type of solvent used to dissolve the polymer as well as the polymer concentration and molecular weight, the mean diameter of the particles varied between 3.0 to 5.5 μm. Fluorescence microscopic analysis of the electrosprayed particles using FITC-conjugated BSA demonstrated the core-shell structure of the developed particles. The encapsulation efficiency and release behavior of BSA was influenced by shell:core feeding ratio, protein concentration, and the electrospraying method. The encapsulation efficiency of BSA within the core-shell particles of high and low molecular weight PLGA was found 15.7% and 25.1% higher than the emulsion electrosprayed particles, respectively. Moreover, the total amount of BSA released from low molecular weight PLGA particles was significantly higher than high molecular weight PLGA particles within 43 days of release studies, with negligible effect on encapsulation efficiency. The technique of coaxial electrospraying has high potential for encapsulation of susceptible protein-based therapeutic agents such as growth factors for multiple drug delivery applications.

  6. The accretion of solar material onto white dwarfs: No mixing with core material implies that the mass of the white dwarf is increasing

    Directory of Open Access Journals (Sweden)

    Sumner Starrfield

    2014-02-01

    Full Text Available Cataclysmic Variables (CVs are close binary star systems with one component a white dwarf (WD and the other a larger cooler star that fills its Roche Lobe. The cooler star is losing mass through the inner Lagrangian point of the binary and some unknown fraction of this material is accreted by the WD. One consequence of the WDs accreting material, is the possibility that they are growing in mass and will eventually reach the Chandrasekhar Limit. This evolution could result in a Supernova Ia (SN Ia explosion and is designated the Single Degenerate Progenitor (SD scenario. This paper is concerned with the SD scenario for SN Ia progenitors. One problem with the single degenerate scenario is that it is generally assumed that the accreting material mixes with WD core material at some time during the accretion phase of evolution and, since the typical WD has a carbon-oxygen CO core, the mixing results in large amounts of carbon and oxygen being brought up into the accreted layers. The presence of enriched carbon causes enhanced nuclear fusion and a Classical Nova explosion. Both observations and theoretical studies of these explosions imply that more mass is ejected than is accreted. Thus, the WD in a Classical Nova system is losing mass and cannot be a SN Ia progenitor. However, the composition in the nuclear burning region is important and, in new calculations reported here, the consequences to the WD of no mixing of accreted material with core material have been investigated so that the material involved in the explosion has only a Solar composition. WDs with a large range in initial masses and mass accretion rates have been evolved. I find that once sufficient material has been accreted, nuclear burning occurs in all evolutionary sequences and continues until a thermonuclear runaway (TNR occurs and the WD either ejects a small amount of material or its radius grows to about 1012 cm and the evolution is ended. In all cases where mass ejection occurs

  7. Electrochemical One-Electron Oxidation of Low-Generation Polyamidoamine-Type Dendrimers with a 1,4-Phenylenediamine Core

    DEFF Research Database (Denmark)

    Hammerich, Ole; Hansen, Thomas; Thorvildsen, Asbjørn

    2009-01-01

    A series of polyamidoamine (PAMAM)-type dendrimers with a 1,4-phenylenediamine (PD) core is prepared from PD by procedures including Michael addition of methyl acrylate followed by aminolysis with 1,2-ethanediamine. Their one-electron oxidation potentials are determined by differential pulse...... caused by interactions between the positive charge centered at the core and the neighboring ester or amide dipoles. The relative ease of oxidation of TMePD and the lowest members of the series of the dendrimers can be reproduced theoretically only when solvation was included in the calculations. The DPV...

  8. Calculation of neutron and gamma fluxes in support to the interpretation of measuring devices irradiated in the core periphery of the OSIRIS Material Testing Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Malouch, Fadhel [Alternative Energies and Atomic Energy Commission - CEA, Saclay Center, DEN/DANS/DM2S/SERMA, F-91191 Gif-sur-Yvette Cedex (France)

    2015-07-01

    Technological irradiations carried out in material testing reactors (MTRs) are used to study the behavior of materials under irradiation conditions required by different types of nuclear power plants (NPPs). For MTRs, specific instrumentation is required for the experiment monitoring and for the characterization of irradiation conditions, in particular the flux of neutrons and photons. To measure neutron and photon flux in experimental locations, different sensors can be used, such as SPNDs (self-powered neutron detectors), SPGDs (self-powered gamma detectors) and ionization chambers. These sensors involve interactions producing ultimately a measurable electric current. Various sensors have been recently tested in the core periphery of the OSIRIS reactor (located at the CEA-Saclay center) in order to qualify their responses to the neutron and the photon flux. One of the key input data for this qualification is to have a relevant evaluation of neutron and gamma fluxes at the irradiation location. The objective of this work is to evaluate the neutron and the gamma flux in the core periphery of the OSIRIS reactor. With this intention, specific neutron-photonic three-dimensional calculations have been performed and are mainly based on the TRIPOLI-4{sup R} three-dimensional continuous-energy Monte Carlo code, developed by CEA (Saclay Center) and extensively validated against reactor dosimetry benchmarks. In the case of the OSIRIS reactor, TRIPOLI-4{sup R} code has been validated against experimental results based on neutron flux and nuclear heating measurements performed in ex-core and in-core experiments. In this work, simultaneous contribution of neutrons and gamma photons in the core periphery is considered using neutron-photon coupled transport calculations. Contributions of prompt and decay photons have been taken into account for the gamma flux calculation. Specific depletion codes are used upstream to provide the decay-gamma sources required by TRIPOLI-4

  9. Suppression of Higher-Order Modes by Segmented Core Doping in Rod-Type Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Poli, Federica; Lægsgaard, Jesper; Passaro, Davide;

    2009-01-01

    Abstract—A large mode area Yb-doped rod-type photonic crystal fiber design with a low refractive index ring in the core is proposed to provide an improved suppression of the first higher-order mode compared to the case of uniform core doping, in a way which is more robust against fluctuations......, a spatial and spectral amplifier model has been considered to study the gain competition among the fundamental and the first higher-order mode guided in the Yb-doped rod-type fibers. Results have demonstrated the effectiveness of the low refractive index ring in suppressing the higher-order mode, thus...... providing an effectively single-mode behavior for the rod-type fibers....

  10. Development of adaptive core emulator for PMS-XRBP of CE type plant

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jae Seung; Zee, Sung Quun; Lee, Chung Chan; Lee, Ki Bog; Rhy, Hyo Sang; Chang, Jong Hwa; Lee, Young Ouk; Baek, Seung Min; Seo, Ho Joon

    1996-12-01

    The purpose of this report is to develop ONED-based adaptive core emulator (ACE) for Korean Standard Nuclear Power Plant. This report is first year report and includes (1) augmentation of ONED94 I/O system (2) non-equilibrium xenon initialization for core transient simulation (3) ONED94 verification via plant measurements (4) automatic data link system from PMS and personal computer. (author). 4 tabs., 4 figs., 8 refs.

  11. Numerical Analysis of Magnetic Force of Dry-Type Air-Core Reactor

    Institute of Scientific and Technical Information of China (English)

    LIUZhi-gang; GENGYing-san; WANGJian-hua

    2004-01-01

    This paper presents a coupled magnetic-circuit method for computing the magnetic force of air-core reactor under short-time current. The current and the magnetic flux density are computed first and then the magnetic force is obtained. Thus, the dynamic stability performance of air-core reactor can be analyzed at the design stage to reduce experimental cost and shorten the lead-time of product development.

  12. Synthesis of Magnetic Rattle-Type Silica with Controllable Magnetite and Tunable Size by Pre-Shell-Post-Core Method.

    Science.gov (United States)

    Chen, Xue; Tan, Longfei; Meng, Xianwei

    2016-03-01

    In this study, we have developed the pre-shell-post-core route to synthesize the magnetic rattle-type silica. This method has not only simplified the precursor's process and reduced the reacting time, but also ameliorated the loss of magnetite and made the magnetite content and the inner core size controllable and tunable. The magnetite contents and inner core size can be easily controlled by changing the type and concentration of alkali, reaction system and addition of water. The results show that alkali aqueous solution promotes the escape of the precursor iron ions from the inner space of rattle-type silica and results in the loss of magnetite. In this case, NaOH ethanol solution is better for the formation of magnetite than ammonia because it not only offers an appropriate alkalinity to facilitate the synthesis of. magnetic particles, but also avoids the escape of the iron ions from the mesopores of rattle-type silica. The synthesis process is very simple and efficient, and it takes no more than 2 hours to complete the total preparation and handling of the magnetic rattle-type silica. The end-product Fe3O4@SiO2 nanocomposites also have good magnetic properties which will perform potential application in biomedical science.

  13. ROP MATHEMATICAL MODEL OF ROTARY-ULTRASONIC CORE DRILLING OF BRITTLE MATERIAL

    Directory of Open Access Journals (Sweden)

    Mera Fayez Horne

    2017-03-01

    Full Text Available The results from the Phoenix mission led scientists to believe it is possible that primitive life exists below the Martian surface. Therefore, drilling in Martian soil in search for organisms is the next logical step. Drilling on Mars is a major engineering challenge due to the drilling depth requirement and extreme environment condition. Mars lacks a thick atmosphere and a continuous magnetic field that shield the planet’s surface from solar radiation and solar flares. As a result, the Martian surface is sterile and if life ever existed, it must be found below the surface. NASA’s Mars Exploration Payload Advisory Group proposed that drilling should be considered as a priority investigation on Mars in an effort of finding evidence of extinct or extant life. The results from the Curiosity mission suggested drilling six meters deep in the red planet in search for life. Excavation tools deployed to Mars so far have been able to drill to a maximum depth of 6.5 cm. Thus, the drilling capabilities need to be increased by a factor of approximately 100 to achieve the goal of drilling six meters deep. This requirement puts a demand on developing new and more effective technologies to reach this goal. Previous research shows evidence of a promising drilling mechanism in rotary-ultrasonic for what it offers in terms of high surface quality, faster rate of penetration and higher material removal rate. This research addresses the need to understand the mechanics of the drill bit tip and rock interface in rotary-ultrasonic drilling performance of one drill bit at a time drilling in three types of rocks that vary in strength. A mathematical model identifying all contributing independent parameters, such as drill bit design parameters, drilling process parameters, ultrasonic wave amplitude and rocks’ material properties, that have effect on rate of penetration is developed. Analytical and experimental results under ambient condition are presented to show

  14. Material combinations and parametric study of thermal and mechanical performance of pyramidal core sandwich panels used for hypersonic aircrafts

    Science.gov (United States)

    Zhang, Ruiping; Zhang, Xiaoqing; Lorenzini, Giulio; Xie, Gongnan

    2016-11-01

    A novel kind of lightweight integrated thermal protection system, named pyramidal core sandwich panel, is proposed to be a good safeguard for hypersonic aircrafts in the current study. Such system is considered as not only an insulation structure but also a load-bearing structure. In the context of design for hypersonic aircrafts, an efficient optimization should be paid enough attention. This paper concerns with the homogenization of the proposed pyramidal sandwich core panel using two-dimensional model in subsequent research for material selection. According to the required insulation performance and thermal-mechanical properties, several suitable material combinations are chosen as candidates for the pyramidal core sandwich panel by adopting finite element analysis and approximate response surface. To obtain lightweight structure with an excellent capability of heat insulation and load-bearing, an investigation on some specific design variables, which are significant for thermal-mechanical properties of the structure, is performed. Finally, a good balance between the insulation performance, the capability of load-bearing and the lightweight has attained.

  15. Ultra-high and persistent optical depths of caesium in Kagom\\'e-type hollow-core photonic crystal fibres

    CERN Document Server

    Kaczmarek, Krzysztof T; Sprague, Michael R; Kolthammer, W Steven; Feizpour, Amir; Ledingham, Patrick M; Brecht, Benjamin; Poem, Eilon; Abdolvand, Amir; Russell, Philip St J; Walmsley, Ian A; Nunn, Joshua

    2015-01-01

    Alkali-filled hollow-core fibres are a promising medium for investigating light-matter interactions, especially at the single-photon level, due to the tight confinement of light and high optical depths achievable by light-induced atomic desorption. However, until now these large alkali vapour densities could only be generated for seconds at most once per day, severely limiting the practicality of the technology. Here we report the generation of highest observed transient ($>10^5$ for minutes) and highest observed persistent (>2000 for hours) optical depths of alkali vapours in hollow-core fibres to date, using a caesium-filled Kagom\\'e-type hollow-core photonic crystal fibre. Our results pave the way to light-matter interaction experiments in confined geometries requiring long operation times and large atomic number densities, such as single-photon-level light-matter interaction experiments and fundamental investigations of hot dense atomic gases.

  16. Microwave-assisted synthesis of water-dispersed CdTe/CdSe core/shell type II quantum dots.

    Science.gov (United States)

    Sai, Li-Man; Kong, Xiang Yang

    2011-05-27

    A facile synthesis of mercaptanacid-capped CdTe/CdSe (core/shell) type II quantum dots in aqueous solution by means of a microwave-assisted approach is reported. The results of X-ray diffraction and high-resolution transmission electron microscopy revealed that the as-prepared CdTe/CdSe quantum dots had a core/shell structure with high crystallinity. The core/shell quantum dots exhibit tunable fluorescence emissions by controlling the thickness of the CdSe shell. The photoluminescent properties were dramatically improved through UV-illuminated treatment, and the time-resolved fluorescence spectra showed that there is a gradual increase of decay lifetime with the thickness of CdSe shell.

  17. Microwave-assisted synthesis of water-dispersed CdTe/CdSe core/shell type II quantum dots

    Directory of Open Access Journals (Sweden)

    Sai Li-Man

    2011-01-01

    Full Text Available Abstract A facile synthesis of mercaptanacid-capped CdTe/CdSe (core/shell type II quantum dots in aqueous solution by means of a microwave-assisted approach is reported. The results of X-ray diffraction and high-resolution transmission electron microscopy revealed that the as-prepared CdTe/CdSe quantum dots had a core/shell structure with high crystallinity. The core/shell quantum dots exhibit tunable fluorescence emissions by controlling the thickness of the CdSe shell. The photoluminescent properties were dramatically improved through UV-illuminated treatment, and the time-resolved fluorescence spectra showed that there is a gradual increase of decay lifetime with the thickness of CdSe shell.

  18. Aging performances for resisting low-temperature of three dental yttria-stabilized zirconia ceramic core materials

    Institute of Scientific and Technical Information of China (English)

    XIAO Rui; CHU Bing-feng; ZHANG Lan; CAO Jun-kai

    2012-01-01

    Background The low-temperature resistance aging performance of Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) is the key effective factor that influences the long-term success rate of prosthesis.The objective of this study was to test and compare the aging performances for resisting low temperature of Lava Frame,Cercon Smart,and Upcera Yttria-stabilized zirconia core materials,via analyzing the micro and the crystal phases of the materials,and measure the three-point bending strength and the fracture toughness.Methods The three zirconia green bodies were prepared as 60 test samples for three-point bending strength and as 60 test samples for fracture toughness.The test samples for three-point bending strength and fracture toughness were assigned to five groups and were treated respectively for 0,5,10,15,and 20 hours to observe the micro and the crystal phases of the test samples.Then the three-point bending strength and fracture toughness were tested by X-ray diffraction (XRD).Results The m phase content of Lava Frame was raised from 7.70% to 13.01%; the m phase content of Cercon Smart was raised from 4.95% to 8.53%; and Lava Frame is raised from 10.84% to 35.18%.The three-point bending strengths of the three zirconia core materials were higher than 1100 MPa and the fracture toughness was higher than 3 MPa·m1/2.The three-point bending strength and the fracture toughness of Upcra zirconia decreased the most,followed by Lava Frame,and then by Cercon Smart.Conclusion The aging resistance sequences of the three zirconia core materials are,from strong to weak,Cercon Smart,Lava Frame,and Upcera.

  19. Physical properties of molten core materials: Zr-Ni and Zr-Cr alloys measured by electrostatic levitation

    Science.gov (United States)

    Ohishi, Yuji; Kondo, Toshiki; Ishikawa, Takehiko; Okada, Junpei T.; Watanabe, Yuki; Muta, Hiroaki; Kurosaki, Ken; Yamanaka, Shinsuke

    2017-03-01

    It is important to understand the behaviors of molten core materials to investigate the progression of a core meltdown accident. In the early stages of bundle degradation, low-melting-temperature liquid phases are expected to form via the eutectic reaction between Zircaloy and stainless steel. The main component of Zircaloy is Zr and those of stainless steel are Fe, Ni, and Cr. Our group has previously reported physical property data such as viscosity, density, and surface tension for Zr-Fe liquid alloys using an electrostatic levitation technique. In this study, we report the viscosity, density, and surface tension of Zr-Ni and Zr-Cr liquid alloys (Zr1-xNix (x = 0.12 and 0.24) and Zr0.77Cr0.23) using the electrostatic levitation technique.

  20. The Accretion of Solar Material onto White Dwarfs: No Mixing with Core Material Implies that the Mass of the White Dwarf is Increasing

    CERN Document Server

    Starrfield, Sumner

    2015-01-01

    Cataclysmic Variables (CVs) are close binary star systems with one component an accreting white dwarf (WD) and the other a larger cooler star that fills its Roche Lobe. One consequence of the WDs accreting material, is the possibility that they are growing in mass and will eventually reach the Chandrasekhar Limit. This evolution could result in a Supernova Ia (SN Ia) explosion and is designated the Single Degenerate Progenitor (SD) scenario. One problem with the single degenerate scenario is that it is generally assumed that the accreting material mixes with WD core material at some time during the accretion phase of evolution and, since the typical WD has a carbon-oxygen (CO) core, the mixing results in large amounts of carbon and oxygen being brought up into the accreted layers. The presence of enriched carbon causes enhanced nuclear fusion and a Classical Nova (CN)explosion. Thus, the WD in a Classical Nova system is decreasing in mass and cannot be a SN Ia progenitor. In new calculations reported here, th...

  1. Magnetocaloric effect study of ferromagnetic-charge ordered core-shell type manganite nanostructures

    Science.gov (United States)

    Das, Kalipada; Das, I.

    2017-08-01

    In the present study we have presented the magnetic and magnetocaloric properties of ferromagnetic (La0.67Sr0.33MnO3)-charge ordered (Pr0.67Ca0.33MnO3) core-shell nanostructures. We have also compared the magnetocaloric properties of Pr0.67Ca0.33MnO3 (PCMO) nanoparticles. Our study indicates that in case of the core-shell nanostructures, the magnetocaloric properties markedly modifies compared to its parent compound PCMO, additionally the low field magnetocaloric effect enhanced. More specifically, the large value of magnetocaloric entropy change (- Δ S(T)) was observed in wider temperature range in core-shell nanostructure which may be important from application point of view.

  2. Viscoelastic effective properties of two types of heterogeneous materials.

    Science.gov (United States)

    Cornet, Jan; Dabrowski, Marcin; Schmid, Daniel

    2015-04-01

    In the past, a lot of efforts have been put to describe two end cases of rock behaviors: elasticity and viscosity. In recent years, more focus has been brought on the intermediate viscoelastic cases which describe better the rheology of rocks such as shales. Shales are typically heterogeneous and the question arises as to how to derive their effective properties so that they can be approximated as homogeneous media. This question has already been dealt with at the elastic and viscous limit but still remains for some cases in between. Using MILAMIN, a fast finite element solver for large problems, we numerically investigate different approaches to derive the effective properties of several viscoelastic media. Two types of geometries are considered: layered and inclusion based media. We focus on two dimensional plane strain problems considering two phase composites deformed under pure shear. We start by investigating the case of transversely isotropic layered media made of two Maxwell materials. Using the Backus averaging method we discuss the degree of relevance of this averaging by considering some parameters as: layer periodicity, layer thickness and layer interface roughness. Other averaging methods are also discussed which provide a broader perspective on the performances of Backus averaging. In a second part we move on to inclusion based models. The advantage of these models compared to the previous one is that they provide a better approximation to real microstructures in rocks. The setup we consider in this part is the following: some viscous circular inclusions are embedded in an elastic matrix. Both the inclusions and the matrix are homogeneous but the inclusions are purely isotropic while the matrix can also be anisotropic. In order to derive the effective viscoelastic properties of the medium we use two approaches: the self-consistent averaging and the differential effective medium theory. The idea behind self-consistency is to assume that the inclusions

  3. Comparison of the microtensile bond strength of different composite core materials and bonding systems to a fiber post (DT Light

    Directory of Open Access Journals (Sweden)

    Lelya Sadighpour

    2013-10-01

    Full Text Available   Background and Aims: Retention and stability of the post and core system is the key factor for success of final restoration . The aim of this study was to evaluate the microtensile bond strength of the different composite core materials and bonding systems to a fiber post.   Materials and Methods: To evaluate the bond strength of the composite resins to a fiber post ( DT light post 60 posts were divided into six groups : group A: Heliomolar Flow + Seal Bond, group B: Heliomolar Flow + SE Bond , group C: Valux Plus + Seal Bond , group D: Valux Plus + SE Bond , group E: Corecem + Seal Bond, group F: Corecem + SE Bond. All samples were thermocycled for 5000 cycles (5-55 0C and cut into four bars for the microtensile bond strength test. Failure modes were identified using a stereomicroscope. Data were analysed using One-way ANOVA and Tukey HSD post hoc test (P<0.05.   Results: The interaction between composite resin materials and bonding systems were positive. The conventional hybrid composite (Valux Plus had significantly higher bond strength compared with the core specific flowable composite (Corecem when Seal Bond was applied as bonding agent (P<0.05. However, when SE Bond was utilized hybrid composite demonstrated significantly lower bond strength than that of other two groups (P<0.05.   Conclusion: The performance of a particular composite is affected by the bonding system that is applied. A single composite resin may have different bond strength when combined with different bonding system.

  4. Compression-Coated Tablet for Colon Targeting: Impact of Coating and Core Materials on Drug Release.

    Science.gov (United States)

    Maity, Siddhartha; Sa, Biswanath

    2016-04-01

    This work was envisaged to develop compression-coated tablets using a blend of Ca(+2) ion cross-linked carboxymethyl xanthan gum (CMXG) and sodium alginate (SAL) for delayed release of immediate pulse release tablets of prednisolone (PDL) in the colon without the need of colonic bacterial intervention for degradation of the polysaccharide coat. The core tablets containing PDL and other compatible excipients were prepared by direct compression method and subsequently compression coated with different ratios of CMXG and SAL. Long T lag, the time required to restrict the drug release below 10%, and short T rap, the time required for immediate release following the T lag, were considered as suitable release parameters for evaluation of colon targeting of PDL tablets. Among the various compression coats, a blend of CMXG and SAL in a ratio of 1.5:3.5 provided T lag of 5.12 ± 0.09 h and T rap of 6.50 ± 0.05 h. The increase in microcrystalline cellulose (MCC) and crospovidone (CP) in the core tablets did not change T lag significantly although decreased the T rap marginally. Inclusion of an osmogen in the core tablets decreased the T lag to 4.05 ± 0.08 h and T rap to 3.56 ± 0.06 h. The increase in coat weight to 225 mg provided a reasonably long T lag (6.06 ± 0.09 h) and short T rap (4.36 ± 0.20 h). Drug release from most of the formulations followed the Hixson-Crowell equation and sigmoidal pattern as confirmed by the Weibull equation. In conclusion, tablets, compression coated with CMXG and SAL in a ratio of 1.5:3.5 and having 225-mg coat weight, were apparently found suitable for colon targeting.

  5. Dielectric technique to measure the twist elastic constant of liquid crystals: the case of a bent-core material.

    Science.gov (United States)

    Salamon, P; Eber, N; Seltmann, J; Lehmann, M; Gleeson, J T; Sprunt, S; Jákli, A

    2012-06-01

    The effect of director pretilt on the twist magnetic Fréedericksz transition of nematics was investigated in a planar cell. The director configuration was calculated as a function of magnetic inductance. The dielectric and optical response of the nematic liquid crystal was numerically modeled. A dielectric measurement method for determining the elastic constant K_{22} is presented. The influence of the conditions for the Mauguin effect is discussed. The theoretical predictions were confirmed by our experiments. Experimental data for all elastic constants of a bent-core nematic material are presented and discussed.

  6. Molecular dynamics study on core-shell structure stability of aluminum encapsulated by nano-carbon materials

    Science.gov (United States)

    Yi, Qingwen; Xu, Jingcheng; Liu, Yi; Zhai, Dong; Zhou, Kai; Pan, Deng

    2017-02-01

    A ReaxFF reactive forcefield for aluminum-carbon composite system has been developed to investigate structural stability and thermal decomposition mechanism of nano-carbon materials coating aluminum particles. Research results indicated the Al@C particles were structurally stable in a broad temperature range from room temperature up to 2735 K. In particular, the broken carbon cage self-healed to reconstruct a more stable Al@C core-shell structure after Al atoms sequentially departing from carbon cage during thermal decomposition, proffering an effective protection for aluminum surface-activeness.

  7. Estimation of fracture parameters in foam core materials using thermal techniques

    DEFF Research Database (Denmark)

    Dulieu-Barton, J. M.; Berggreen, Christian; Boyenval Langlois, C.

    2010-01-01

    The paper presents some initial work on establishing the stress state at a crack tip in PVC foam material using a non-contact infra-red technique known as thermoelastic stress analysis (TSA). A parametric study of the factors that may affect the thermoelastic response of the foam material...... is described. A mode I simulated crack in the form of a machined notch is used to establish the feasibility of the TSA approach to derive stress intensity factors for the foam material. The overall goal is to demonstrate that thermal techniques have the ability to provide deeper insight into the behaviour...

  8. Effect of three different core materials on the fracture resistance of endodontically treated deciduous mandibular second molars: an in vitro study.

    Science.gov (United States)

    Shah, Preetam; Gugwad, Sachin C; Bhat, Chetan; Lodaya, Rahul

    2012-01-01

    Endodontic treatment makes the tooth brittle due to loss of bulk of tooth structure, decrease in the moisture content of dentin and dentin elasticity. The following study was carried out to evaluate the effect of endodontic treatment on the fracture resistance of the tooth and reinforcing ability of three different core materials. The following study comprised of sample size of 30 deciduous second molars divided into control group (6) and test group (24). Access opening was done in 24 and 18th teeth with access opening were restored with three different core materials namely IRM (6), silver amalgam (6), GIC (6). All the 30 were subjected to fracture test using UTM (Universal testing machine)- Instron 95. Result showed a drastic reduction in the fracture resistance of the tooth on access opening (1/3rd) and out of the three core materials glass ionomer was shown to be the best core material giving the highest fracture registrance followed by silver amalgam and IRM.

  9. Effects of different surface treatments on the bond strength of glass fiber-reinforced composite root canal posts to composite core material

    Directory of Open Access Journals (Sweden)

    Murat Kurt

    2012-03-01

    Conclusion: Er:YAG laser treatments on the FRC post surface decreased the bond strength. Airborne-particle abrasion and HF acid etching are alternative methods for increasing bond strength of FRC posts to composite core material.

  10. Cumene cracking on modified mesoporous material type MCM-41

    Directory of Open Access Journals (Sweden)

    Ahmed Belhakem

    2006-06-01

    Full Text Available The effect of ionic exchange degree of aluminated mesoporous materials H(X-AlMCM-41 materials, the method of its exchange mode and its grains form were investigated for the mesoporous catalytic activity in the cumene (i.e. isopropylbenzene cracking reaction. Benzene, propylene and xylene derivatives are the main products of this reaction. Olefins like butene and pentene appeared as the products of secondary reactions. No saturated hydrocarbons, except traces of butane, nor ethylbenzene and toluene were formed and seemed to be typical products of secondary reactions obtained with HNaY zeolites. Generally the exchanged H(X-AlMCM-41 materials by the substitution of Na+ by NH4+ are more active than those exchanged directly with acid solution (substitution of Na+ by H+ even if both the two methods used exhibit a comparable content of acid sites within catalysts at a low exchange degrees. However, the first method of exchange has exhibited an important acidity for mesoporous materials when the ionic exchange degree was increased up to 90%; it was probably due not only to the percentage of exchanged degree but also to the distribution of acid sites within the materials.

  11. Molecular characterization and polyclonal antibody generation against core component CagX protein of Helicobacter pylori type IV secretion system

    Science.gov (United States)

    Gopal, Gopal Jee; Kumar, Awanish; Pal, Jagannath; Mukhopadhyay, Gauranga

    2014-01-01

    Gram-negative bacteria Helicobacter pylori cause gastric ulcer, duodenal cancer, and found in almost half of the world’s residents. The protein responsible for this disease is secreted through type IV secretion system (TFSS) of H. pylori. TFSS is encoded by 40-kb region of chromosomal DNA known as cag-pathogenicity island (PAI). TFSS comprises of three major components: cytoplasmic/inner membrane ATPase, transmembrane core-complex and outer membranous pilli, and associated subunits. Core complex consists of CagX, CagT, CagM, and Cag3(δ) proteins as per existing knowledge. In this study, we have characterized one of the important component of core-complex forming sub-unit protein, i.e., CagX. Complete ORF of CagX except signal peptide coding region was cloned and expressed in pET28a vector. Purification of CagX protein was performed, and polyclonal anti-sera against full-length recombinant CagX were raised in rabbit model. We obtained a very specific and high titer, CagX anti-sera that were utilized to characterize endogenous CagX. Surface localization of CagX was also seen by immunofluorescence microscopy. In short for the first time a full-length CagX was characterized, and we showed that CagX is the part of high molecular weight core complex, which is important for assembly and function of H. pylori TFSS. PMID:24637488

  12. Design novel dual agonists for treating type-2 diabetes by targeting peroxisome proliferator-activated receptors with core hopping approach.

    Directory of Open Access Journals (Sweden)

    Ying Ma

    Full Text Available Owing to their unique functions in regulating glucose, lipid and cholesterol metabolism, PPARs (peroxisome proliferator-activated receptors have drawn special attention for developing drugs to treat type-2 diabetes. By combining the lipid benefit of PPAR-alpha agonists (such as fibrates with the glycemic advantages of the PPAR-gamma agonists (such as thiazolidinediones, the dual PPAR agonists approach can both improve the metabolic effects and minimize the side effects caused by either agent alone, and hence has become a promising strategy for designing effective drugs against type-2 diabetes. In this study, by means of the powerful "core hopping" and "glide docking" techniques, a novel class of PPAR dual agonists was discovered based on the compound GW409544, a well-known dual agonist for both PPAR-alpha and PPAR-gamma modified from the farglitazar structure. It was observed by molecular dynamics simulations that these novel agonists not only possessed the same function as GW409544 did in activating PPAR-alpha and PPAR-gamma, but also had more favorable conformation for binding to the two receptors. It was further validated by the outcomes of their ADME (absorption, distribution, metabolism, and excretion predictions that the new agonists hold high potential to become drug candidates. Or at the very least, the findings reported here may stimulate new strategy or provide useful insights for discovering more effective dual agonists for treating type-2 diabetes. Since the "core hopping" technique allows for rapidly screening novel cores to help overcome unwanted properties by generating new lead compounds with improved core properties, it has not escaped our notice that the current strategy along with the corresponding computational procedures can also be utilized to find novel and more effective drugs for treating other illnesses.

  13. Manufacturing technology of the composite materials: nanocrystalline material – polymer type

    OpenAIRE

    B. Ziębowicz; D. Szewieczek; L.A. Dobrzański

    2005-01-01

    Purpose: This paper presents the material and technological solution which makes it possible to obtain the nanocrystalline, ferromagnetic powder material of Fe73.5Cu1Nb3Si13.5B9 alloy after its thermal nanocrystallization with the succeeding high-energy milling. Another aspect was to develop the technology to obtain the nanocrystalline composite materials made by binding the obtained powder material with the high density low-pressures polyethylene (PEHD) with the controlled ferromagnetic and ...

  14. Compressive strength and the effect of duration after photo-activation among dual-cure bulk fill composite core materials.

    Science.gov (United States)

    Alkhudhairy, Fahad; Vohra, Fahim

    2016-01-01

    To assess compressive strength and effect of duration after photoactivation on the compressive strength of different dual cure bulk fill composites. Seventy-two disc shaped (4x10mm) specimens were prepared from three dual cure bulk fill materials, ZirconCore (ZC) (n=24), MulticCore Flow (MC) (n=24) and Luxacore Dual (LC) (n=24). Half of the specimens in each material were tested for failure loads after one hour [MC1 (n=12), LC1 (n=12) & ZC1 (n=12)] and the other half in 7 days [MC7 (n=12), LC7 (n=12), ZC7 (n=12)] from photo-polymerization using the universal testing machine at a cross-head speed of 0.5 cm/minutes. Compressive strength was calculated using the formula UCS=4f/πd(2). Compressive strengths among different groups were compared using analysis of variance (ANOVA) and Tukey's multiple comparisons test. Maximum and minimum compressive strengths were observed in ZC7 (344.14±19.22) and LC1 (202.80±15.52) groups. Specimens in LC1 [202.80 (15.52)] showed significantly lower compressive strength as compared to MC1 [287.06 (15.03)] (pstrengths compared to LC7 [324.56 (19.47)] and MC7 [315.26 (12.36)]. Compressive strengths among all three materials were significantly higher (pstrength compared to MC and LC. Increasing the post photo-activation duration (from one hour to 7 days) significantly improves the compressive strengths of dual cure bulk fill material.

  15. Revision of type material of nivicolous species of Stemonitales

    NARCIS (Netherlands)

    Singer, H.; Moreno, G.; Illana, C.

    2005-01-01

    The types of Comatricha anastomosans Kowalski, C. filamentosa Meyl., C. suksdorfii Ellis & Everh. var. aggregata Meyl. and Lamproderma longifilum H. Neubert, Nowotny & K. Baumann were studied. Comatricha anastomosans is synonymized with C. filamentosa, C. suksdorfii var. aggregata with Symphytocarpu

  16. Nano-magnetic particles used in biomedicine: core and coating materials.

    Science.gov (United States)

    Karimi, Z; Karimi, L; Shokrollahi, H

    2013-07-01

    Magnetic nanoparticles for medical applications have been developed by many researchers. Separation, immunoassay, drug delivery, magnetic resonance imaging and hyperthermia are enhanced by the use of suitable magnetic nanoparticles and coating materials in the form of ferrofluids. Due to their low biocompatibility and low dispersion in water solutions, nanoparticles that are used for biomedical applications require surface treatment. Various kinds of coating materials including organic materials (polymers), inorganic metals (gold, platinum) or metal oxides (aluminum oxide, cobalt oxide) have been attracted during the last few years. Based on the recent advances and the importance of nanomedicine in human life, this paper attempts to give a brief summary on the different ferrite nano-magnetic particles and coatings used in nanomedicine.

  17. A resin composite material containing an eugenol derivative for intracanal post cementation and core build-up restoration.

    Science.gov (United States)

    Almaroof, A; Rojo, L; Mannocci, F; Deb, S

    2016-02-01

    To formulate and evaluate new dual cured resin composite based on the inclusion of eugenyl methacrylate monomer (EgMA) with Bis-GMA/TEGDMA resin systems for intracanal post cementation and core build-up restoration of endodontically treated teeth. EgMA was synthesized and incorporated at 5% (BTEg5) or 10% (BTEg10) into dual-cure formulations. Curing properties, viscosity, Tg, radiopacity, static and dynamic mechanical properties of the composites were determined and compared with Clearfil™DC Core-Plus, a commercial dual-cure, two-component composite. Statistical analysis of the data was performed with ANOVA and the Tukey's post-hoc test. The experimental composites were successfully prepared, which exhibited excellent curing depths of 4.9, 4.7 and 4.2 mm for BTEg0, BTEg5 and BTEg10 respectively, which were significantly higher than Clearfil™DC. However, the inclusion of EgMA initially led to a lower degree of cure, which increased when measured at 24 h with values comparable to formulations without EgMA, indicating post-curing. The inclusion of EgMA also lowered the polymerization exotherm thereby reducing the potential of thermal damage to host tissue. Both thermal and viscoelastic analyses confirmed the ability of the monomer to reduce the stiffness of the composites by forming a branched network. The compressive strength of BTEg5 was significantly higher than the control whilst flexural strength increased significantly from 95.9 to 114.8 MPa (BTEg5) and 121.9 MPa (BTEg10). Radiopacity of the composites was equivalent to ∼3 mm Al allowing efficient diagnosis. The incorporation of EgMA within polymerizable formulations provides a novel approach to prepare reinforced resin composite material for intracanal post cementation and core build-up and the potential to impart antibacterial properties of eugenol to endodontic restorations. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  18. Coupled neutronic core and subchannel analysis of nanofluids in VVER-1000 type reactor

    Energy Technology Data Exchange (ETDEWEB)

    Zarifi, Ehsan; Sepanloo, Kamran [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of). Reactor and Nuclear Safety School; Jahanfarnia, Golamreza [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Dept. of Nuclear Engineering, Science and Research Branch

    2017-05-15

    This study is aimed to perform the coupled thermal-hydraulic/neutronic analysis of nanofluids as the coolant in the hot fuel assembly of VVER-1000 reactor core. Water-based nanofluid containing various volume fractions of Al{sub 2}O{sub 3} nanoparticle is analyzed. WIMS and CITATION codes are used for neutronic simulation of the reactor core, calculating neutron flux and thermal power distribution. In the thermal-hydraulic modeling, the porous media approach is used to analyze the thermal behavior of the reactor core and the subchannel analysis is used to calculate the hottest fuel assembly thermal-hydraulic parameters. The derived conservation equations for coolant and conduction heat transfer equation for fuel and clad are discretized by Finite volume method and solved numerically using visual FORTRAN program. Finally the analysis results for nanofluids and pure water are compared together. The achieved results show that at low concentration (0.1 percent volume fraction) alumina is the optimum nanoparticles for normal reactor operation.

  19. Analytical core loss calculations for magnetic materials used in high frequency high power converter applications. Ph.D. Thesis - Toledo Univ.

    Science.gov (United States)

    Triner, J. E.

    1979-01-01

    The basic magnetic properties under various operating conditions encountered in the state-of-the-art DC-AC/DC converters are examined. Using a novel core excitation circuit, the basic B-H and loss characteristics of various core materials may be observed as a function of circuit configuration, frequency of operation, input voltage, and pulse-width modulation conditions. From this empirical data, a mathematical loss characteristics equation is developed to analytically predict the specific core loss of several magnetic materials under various waveform excitation conditions.

  20. Transformer core

    NARCIS (Netherlands)

    Mehendale, A.; Hagedoorn, Wouter; Lötters, Joost Conrad

    2010-01-01

    A transformer core includes a stack of a plurality of planar core plates of a magnetically permeable material, which plates each consist of a first and a second sub-part that together enclose at least one opening. The sub-parts can be fitted together via contact faces that are located on either side

  1. Transformer core

    NARCIS (Netherlands)

    Mehendale, A.; Hagedoorn, Wouter; Lötters, Joost Conrad

    2008-01-01

    A transformer core includes a stack of a plurality of planar core plates of a magnetically permeable material, which plates each consist of a first and a second sub-part that together enclose at least one opening. The sub-parts can be fitted together via contact faces that are located on either side

  2. Bifunctional luminescent and magnetic core/shell type nanostructures Fe3O4@CeF3 :Tb3+/Si

    Institute of Scientific and Technical Information of China (English)

    M. Runowski; T. Grzyb, S. Lis

    2011-01-01

    A facile co-precipitation and microemulsion methods were applied to obtain core/shell type nanoparticles.Cerium fluoride doped with terbium(Ⅲ) ions supplied intensive green luminescence of the system.Due to the presence of magnetite nanoparticles as cores,the product was highly sensitive to external magnetic field.Both sorts of nanostructures were encapsulated by silica shell.Such external layer of inert oxide can potentially increase the resistance of prepared nanostructures to thermal oxidation,aggressive agents,changing of pH or destructive radiation.Morphology of the product was examined using transmission electron microscopy (TEM).Formations of the core/shell type nanostructures were clearly seen in the TEM pictures.Powder X-ray diffraction (XRD) confirmed the structure of the products,their nanocrystallinity and amorphous nature of silica shell.Optical properties were investigated by measuring excitation and emission spectra.Such multifunctional luminescent and magnetic nanoparticles coated with easily functionalized silica shell could be applied in many field of science.

  3. Recent progress in the study of core-shell-structured materials with metal organic frameworks (MOFs) as shell%金属有机骨架(MOFs)为壳的核壳结构材料研究进展

    Institute of Scientific and Technical Information of China (English)

    农洁静; 赵文波; 覃显业; 刘彪; 张政

    2015-01-01

    MOFs核壳结构材料是近十几年来化工材料领域的研究热点,其中MOFs可作核,亦可作壳。本文从不同的核出发综述了以 MOFs 为壳的核壳结构材料的合成方法,如外延生长法、后合成修饰法等;概述了其展现出优于核层与壳层的特性(如选择性分离、催化性、磁性等)及以 MOFs 为壳的核壳结构材料在气体吸附、催化剂、磁性分离等应用上的研究,这给MOFs复合材料的产业化带来很大的潜力;而内核主要包括单质金属及非金属类内核、氧化物类内核、MOFs类内核;最后对MOFs为壳的核壳结构复合材料合成方法的改进和拓展、结构均一稳定、多功能化的发展作了展望。%Core-shell-structure MOFs materials became a hot spot in the field of chemical and materials over the last decade,and MOFs can act as core or shell. This paper mainly reviews the synthesis methods of core-shell-structure material with MOFs as shell according to different nuclear types,such as epitaxial growth method,and post-synthetic modifications;and summarizes the performances which are better than single core or shell,such as separation selectivity,catalysis,magnetic performance, and the development of the core-shell-structure materials with MOFs as shell in gas adsorption, catalysts,magnetic separation,which bring a large potential for MOFs composite industrialization. The cores include metallic and non-metallic element core , oxides core , and MOFs core. And the core-shell-structure composites with MOFs as shell are prospected for the improvement and development of synthesis methods in order to obtain uniform and stable structure and multi-function.

  4. A Core Collection of Print Material for Libraries Serving the Spanish-Speaking of the Southwest.

    Science.gov (United States)

    REFORMA, Tucson, AZ.

    This booklist prepared by the Arizona chapter of REFORMA, an organization established to promote better library services and programs for the Spanish speaking population of the southwest, presents a representative sample of printed materials dealing with literature and language, traditions and customs, history and heritage, the arts, and applied…

  5. A Core Collection of Print Material for Libraries Serving the Spanish-Speaking of the Southwest.

    Science.gov (United States)

    REFORMA, Tucson, AZ.

    This booklist prepared by the Arizona chapter of REFORMA, an organization established to promote better library services and programs for the Spanish speaking population of the southwest, presents a representative sample of printed materials dealing with literature and language, traditions and customs, history and heritage, the arts, and applied…

  6. Dopant type and/or concentration selective dry photochemical etching of semiconductor materials

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, C.R.H.; Dishman, J.L.

    1985-10-11

    Disclosed is a method of selectively photochemically dry etching a first semiconductor material of a given composition in the presence of a second semiconductor material which is of a composition different from said first material, said second material substantially not being etched during said method. The method comprises subjecting both materials to the same photon flux of an energy greater than their respective direct bandgaps and to the same gaseous chemical etchant under conditions where said etchant would be ineffective for chemical etching of either material were the photons not present, said conditions also being such that the resultant electronic structure of the first semiconductor material under said photon flux is sufficient for the first material to undergo substantial photochemical etching under said conditions and being such that the resultant electronic structure of the second semiconductor material under said photon flux is not sufficient for the second material to undergo substantial photochemical etching under said conditions. In a preferred mode, the materials are subjected to a bias voltage which suppresses etching in n- or p-type material but not in p- or n-type material, respectively; or suppresses etching in the more heavily doped of two n-type or two p-type materials.

  7. Dopant type and/or concentration selective dry photochemical etching of semiconductor materials

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, Carol I. H. (Edgewood, NM); Dishman, James L. (Albuquerque, NM)

    1987-01-01

    A method of selectively photochemically dry etching a first semiconductor material of a given composition in the presence of a second semiconductor material which is of a composition different from said first material, said second material substantially not being etched during said method, comprises subjecting both materials to the same photon flux of an energy greater than their respective direct bandgaps and to the same gaseous chemical etchant under conditions where said etchant would be ineffective for chemical etching of either material were the photons not present, said conditions also being such that the resultant electronic structure of the first semiconductor material under said photon flux is sufficient for the first material to undergo substantial photochemical etching under said conditions and being such that the resultant electronic structure of the second semiconductor material under said photon flux is not sufficient for the second material to undergo substantial photochemical etching under said conditions. In a preferred mode, the materials are subjected to a bias voltage which suppresses etching in n- or p- type material but not in p- or n-type material, respectively; or suppresses etching in the more heavily doped of two n-type or two p-type materials.

  8. Ultrahigh and persistent optical depths of cesium in Kagomé-type hollow-core photonic crystal fibers.

    Science.gov (United States)

    Kaczmarek, Krzysztof T; Saunders, Dylan J; Sprague, Michael R; Kolthammer, W Steven; Feizpour, Amir; Ledingham, Patrick M; Brecht, Benjamin; Poem, Eilon; Walmsley, Ian A; Nunn, Joshua

    2015-12-01

    Alkali-filled hollow-core fibers are a promising medium for investigating light-matter interactions, especially at the single-photon level, due to the tight confinement of light and high optical depths achievable by light-induced atomic desorption (LIAD). However, until now these large optical depths could only be generated for seconds, at most once per day, severely limiting the practicality of the technology. Here we report the generation of the highest observed transient (>10(5) for up to a minute) and highest observed persistent (>2000 for hours) optical depths of alkali vapors in a light-guiding geometry to date, using a cesium-filled Kagomé-type hollow-core photonic crystal fiber (HC-PCF). Our results pave the way to light-matter interaction experiments in confined geometries requiring long operation times and large atomic number densities, such as generation of single-photon-level nonlinearities and development of single photon quantum memories.

  9. Ultrahigh and persistent optical depths of cesium in Kagomé-type hollow-core photonic crystal fibers

    Science.gov (United States)

    Kaczmarek, Krzysztof T.; Saunders, Dylan J.; Sprague, Michael R.; Kolthammer, W. Steven; Feizpour, Amir; Ledingham, Patrick M.; Brecht, Benjamin; Poem, Eilon; Walmsley, Ian A.; Nunn, Joshua

    2015-12-01

    Alkali-filled hollow-core fibres are a promising medium for investigating light-matter interactions, especially at the single-photon level, due to the tight confinement of light and high optical depths achievable by light-induced atomic desorption. However, until now these large optical depths could only be generated for seconds at most once per day, severely limiting the practicality of the technology. Here we report the generation of highest observed transient ($>10^5$ for up to a minute) and highest observed persistent ($>2000$ for hours) optical depths of alkali vapours in a light-guiding geometry to date, using a caesium-filled Kagom\\'e-type hollow-core photonic crystal fibre. Our results pave the way to light-matter interaction experiments in confined geometries requiring long operation times and large atomic number densities, such as generation of single-photon-level nonlinearities and development of single photon quantum memories.

  10. Design and analysis of nanowire p-type MOSFET coaxially having silicon core and germanium peripheral channel

    Science.gov (United States)

    Yu, Eunseon; Cho, Seongjae

    2016-11-01

    In this work, a nanowire p-type metal-oxide-semiconductor field-effect transistor (PMOSFET) coaxially having a Si core and a Ge peripheral channel is designed and characterized by device simulations. Owing to the high hole mobility of Ge, the device can be utilized for high-speed CMOS integrated circuits, with the effective confinement of mobile holes in Ge by the large valence band offset between Si and Ge. Source/drain doping concentrations and the ratio between the Si core and Ge channel thicknesses are determined. On the basis of the design results, the channel length is aggressively scaled down by evaluating the primary DC parameters in order to confirm device scalability and low-power applicability in sub-10-nm technology nodes.

  11. Synthesis, materials characterization and opto(electrical) properties of unsymmetrical azomethines with benzothiazole core

    Science.gov (United States)

    Iwan, Agnieszka; Palewicz, Marcin; Krompiec, Michal; Grucela-Zajac, Marzena; Schab-Balcerzak, Ewa; Sikora, Andrzej

    2012-11-01

    Optical (UV-vis and photoluminescence) properties of two soluble organic molecules based on azomethines with benzothiazole core (BTA1 and BTA2) were reported. The structures of both compounds are characterized by means FTIR, 1H NMR, and 13C NMR spectroscopy and elemental analysis; the results show an agreement with the proposed structure. The investigated compounds emitted blue light. Influence of excitation wavelength and concentration on maximum and intensity of emission of BTA1 and BTA2 was found. Electrochemical properties of the compounds were studied by differential pulse voltammetry. Introduction of fluorine moieties (BTA1) resulted in lower energy band gap (Eg) of approximately ˜0.5 eV, whereas BTA2 showed Eg of ˜2.8 eV. The devices comprised of BTA1 with P3HT:PCBM (1:1:1) showed an open circuit voltage (VOC) of 0.40 V, a short circuit current (JSC) of 1.19 mA/cm2, and a fill factor (FF) of 0.23, giving a power-conversion efficiency (PCE) of 0.10% under AM1.5G irradiation (100 mW/cm2).

  12. Synthesis and properties of Pr-substituted MgZn ferrites for core materials and high frequency applications

    Energy Technology Data Exchange (ETDEWEB)

    Mukhtar, Muhammad Waqas; Irfan, Muhammad [Department of Physics, Federal Urdu University of Arts, Science and Technology, Islamabad 44000 (Pakistan); Ahmad, Ishtiaq; Ali, Ihsan [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Akhtar, Majid Niaz [Department of Physics, COMSATS Institute of Information Technology, Lahore (Pakistan); Khan, Muhammad Azhar [Department of Physics, Islamia University, Bahawalpur (Pakistan); Abbas, Ghazanfar [Department of Physics, COMSATS Institute of Information Technology, Islamabad 44000 (Pakistan); Rana, M.U. [Center of Excellence in Solid State Physics, University of the Punjab, Lahore (Pakistan); Ali, Akbar [Department of Basic Sciences, Riphah International University, Islamabad-44000 (Pakistan); Ahmad, Mukhtar, E-mail: ahmadmr25@yahoo.com [Department of Physics, COMSATS Institute of Information Technology, Islamabad 44000 (Pakistan)

    2015-05-01

    A series of single phase spinel ferrites having chemical formula Mg{sub 0.5}Zn{sub 0.5}Pr{sub x}Fe{sub 2−x}O{sub 4} (x=0.00, 0.05, 0.10, 0.15, 0.20, 0.25) were prepared using the sol–gel technique after sintering at 700 °C. The thermal decomposition behavior of an as prepared powder was investigated by means of DTA/TGA analyses. The sintered powders were then characterized by Fourier transform infrared spectroscope, X-ray diffraction, scanning electron microscope, energy dispersive X-ray spectroscope and vibrating sample magnetometer. X-ray diffraction patterns confirm the single phase spinel structure of prepared ferrites without the presence of any impurity phase. The value of lattice parameter (a) increases with the increase of Pr contents (x) into the spinel lattice. The grain size estimated from electron microscope images is in the range of 2.75–5.4 µm which confirms the spinel crystalline nature of the investigated samples. The saturation magnetization (M{sub s}) decreases whereas coercivity (H{sub c}) increases with the increase of Pr contents (x). The measured parameters suggest that these materials are favorable for high frequency applications and as core materials. - Highlights: • Pr-substituted spinel ferrites synthesized by autocombustion route have been investigated. • The average grain size was in the range of 2.75–5.4 µm estimated by SEM technique. • The (M{sub s}) decreases whereas (H{sub c}) increases with the increase of Pr contents (x). • These parameters are favorable for high frequency applications and as core materials.

  13. 36 CFR 1222.12 - What types of documentary materials are Federal records?

    Science.gov (United States)

    2010-07-01

    ... Federal Records § 1222.12 What types of documentary materials are Federal records? (a) General. To ensure... and 36 CFR 1220.18 and 1222.10 of this subchapter) to agency documentary materials in all formats and... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false What types of...

  14. Synthesis and properties of ZnO-HMD@ZnO-Fe/Cu core-shell as advanced material for hydrogen storage.

    Science.gov (United States)

    Bouazizi, N; Boudharaa, T; Bargougui, R; Vieillard, J; Ammar, S; Le Derf, F; Azzouz, A

    2017-04-01

    In this paper, a new synthetic strategy towards functionalized ZnO-HMD@ZnO-Fe/Cu core-shell using sol-gel process modified by chemical grafting of hexamethylenediamine (HMD) on the core and in-situ dispersion of Cu(0)/Fe(0) as metallic nanoparticles (M-NPs) on the shell. The as-prepared core-shell materials were fully characterized by transmission electron microscopy, X-ray powder diffractometry, diffuse reflectance and FT-IR spectrophotometery, photoluminescence, and complexes impedance spectroscopy measurements. The XRD patterns agreed with that of the ZnO typical wurtzite structure, indicating good crystallinity of ZnO-HMD@ZnO-Fe/Cu, with the presence of Fe(0) and Cu(0) phases. Hexamethylenediamine grafting and M-NPs insertion were highly activated and enhanced the core and shell interface by the physiochemical interaction. After functionalization, luminescence intensities and electrical properties of both core and core-shell nanoparticles are improved, indicating the effects of the surface groups on the charge transfer of ZnO-HMD@ZnO-Fe/Cu. The hydrogen capacity retention was depended strongly on the composition and structure of the obtained core-shell. Iron/Copper-loaded ZnO-HMD@ZnO materials exhibited the highest capacity for hydrogen storage. The excellent stability and performance of the ZnO-HMD@ZnO-Fe/Cu core-shell make it an efficient candidate for hydrogen storage.

  15. The Comparison of Shear Bond Strength Between Fibre Reinforced Composite Posts with Three Different Composite Core Materials – An In vitro Study

    Science.gov (United States)

    Anche, Sampath; Kakarla, Pranitha; Kadiyala, Krishna Kishore; Sreedevi, B.; Chiramana, Sandeep; Dev J., Ravi Rakesh; Manne, Sanjay Dutt; G., Deepthi

    2014-01-01

    Aim: The aim of this study is to compare the shear bond strength between fiber reinforced composite post with three different composite core materials. Materials and Methods: The materials used for the study were: 30 maxillary central incisors, pre fabricated fiber reinforced composite post (postec plus posts), Multi-core heavy body, Ti-core, Fluoro-core, Etchant gel, Silane coupling agent, Dentin bonding agent, Standardized gutta percha points, Rely-X dual cure composite resin. A total of 30 human maxillary central incisor were selected for this study. They were divided into three groups of 10 specimens each namely A, B and C. Results: The results obtained were analyzed by using one way analysis (ANOVA) and Tukey Honestly Significant Difference and they showed highest mean shear bond strength for group C when compared with group A and group B. There is no significant difference in the shear bond strength values between group A and group B. Conclusion: The teeth restored with multicore HB showed highest shear bond strength. The teeth restored with Fluoro core showed lowest shear bond strength. No statistically significant difference exists between the shear bond strength values between Ti-core and Fluoro-core. PMID:24596784

  16. Honeycomb core material for sandwich construction - with common hexagonal walls bonded by thermoplastic resin and free walls carrying layer of resin and masking agent

    NARCIS (Netherlands)

    unknown

    1991-01-01

    Abstract of NL 8902116 (A) In a honeycomb core material for a sandwich construction, the common hexagonal walls are bonded together by a thermoplastic resin, and the free hexagonal walls carry a layer of the same resin and also a masking agent. - A number of plates of raw material are given strips

  17. A self-cleaning porous TiO2-Ag core-shell nanocomposite material for surface-enhanced Raman scattering.

    Science.gov (United States)

    Zou, Xiaoxin; Silva, Rafael; Huang, Xiaoxi; Al-Sharab, Jafar F; Asefa, Tewodros

    2013-01-14

    A porous TiO(2)-Ag core-shell nanocomposite material with a large surface area was synthesized by in situ hydrolyzation of Sn(2+)-grafted titanium glycolate microspheres in the presence of Ag(+) ions. The as-prepared nanocomposite material was shown to serve as an efficient self-cleaning surface-enhanced Raman scattering (SERS) substrate.

  18. Honeycomb core material for sandwich construction - with common hexagonal walls bonded by thermoplastic resin and free walls carrying layer of resin and masking agent

    NARCIS (Netherlands)

    unknown

    1991-01-01

    Abstract of NL 8902116 (A) In a honeycomb core material for a sandwich construction, the common hexagonal walls are bonded together by a thermoplastic resin, and the free hexagonal walls carry a layer of the same resin and also a masking agent. - A number of plates of raw material are given strips

  19. SN 2009ip and SN 2010mc: Early and late-time behavior consistent with core-collapse Type IIn supernovae

    CERN Document Server

    Smith, Nathan; Prieto, Jose

    2013-01-01

    The recent supernova (SN) 2009ip had pre-SN eruptions followed by a final explosion in 2012. Its pre-SN observations make 2009ip the best observed SN progenitor in history, but the unprecedented data on the pre-SN activity has fueled debate about the nature of the 2012 explosion, whether it was a true SN or some extreme non-terminal event. In principle, both types of events could power shock interaction with circumstellar material (CSM), but here we argue that only a core-collapse SN provides a self-consistent explanation. Previously, we demonstrated that the light curves of SN 2009ip and another Type IIn, SN 2010mc, were nearly identical. Here we expand that comparison to their spectra as well, demonstrating that they are both consistent with known Type IIn events. The late-time spectra of SN 2009ip resemble those of the super-luminous SN 2006tf, and the underlying broad component in SN 2009ip's spectra resembles Type II-P events. The recent claim that the late-time spectrum of SN 2009ip is returning to its ...

  20. Experimental investigation of material chemical effects on emergency core cooling pump suction filter performance after loss of coolant accident

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Woon, E-mail: parkjw@dongguk.ac.k [Dongguk University, 707 Seokjang-Dong, Gyeongju, 780-714 (Korea, Republic of); Park, Byung Gi [Soonchunhyang University, Asan, Chungnam, 336-745 (Korea, Republic of); Kim, Chang Hyun [Korea Hydro and Nuclear Power Co., Ltd. 25-1, Jang-dong, Yuseong-gu, Daejeon, 305-343 (Korea, Republic of)

    2009-12-15

    Integral tests of head loss through an emergency core cooling filter screen are conducted, simulating reactor building environmental conditions for 30 days after a loss of coolant accident. A test rig with five individual loops each of whose chamber is established to test chemical product formation and measure the head loss through a sample filter. The screen area at each chamber and the amounts of reactor building materials are scaled down according to specific plant condition. A series of tests have been performed to investigate the effects of calcium-silicate, reactor building spray, existence of calcium-silicate with tri-sodium phosphate (TSP), and composition of materials. The results showed that head loss across the chemical bed with even a small amount of calcium-silicate insulation instantaneously increased as soon as TSP was added to the test solution. Also, the head loss across the filter screen is strongly affected by spray duration and the head loss increase is rapid at the early stage, because of high dissolution and precipitation of aluminum and zinc. After passivation of aluminum and zinc by corrosion, the head loss increase is much slowed down and is mainly induced by materials such as calcium, silicon, and magnesium leached from NUKON{sup TM} and concrete. Furthermore, it is newly found that the spay buffer agent, tri-sodium phosphate, to form protective coating on the aluminum surface and reduce aluminum leaching is not effective for a large amount of aluminum and a long spray.

  1. Composite material made of plasmonic nanoshells with quantum dot cores: loss-compensation and ε-near-zero physical properties.

    Science.gov (United States)

    Campione, Salvatore; Capolino, Filippo

    2012-06-15

    A theoretical investigation of loss-compensation capabilities in composite materials made of plasmonic nanoshells is carried out by considering quantum dots (QDs) as the nanoshells' cores. The QD and metal permittivities are modeled according to published experimental data. We determine the modes with real or complex wavenumber able to propagate in a 3D periodic lattice of nanoshells. Mode analysis is also used to assess that only one propagating mode is dominant in the composite material whose optical properties can hence be described via homogenization theory. Therefore, the material effective permittivity is found by comparing different techniques: (i) the mentioned mode analysis, (ii) Maxwell Garnett mixing rule and (iii) the Nicolson-Ross-Weir method based on transmission and reflection when considering a metamaterial of finite thickness. The three methods are in excellent agreement, because the nanoshells considered in this paper are very subwavelength, thus justifying the parameter homogenization. We show that QDs are able to provide loss-compensated ε-near-zero metamaterials and also loss-compensated metamaterials with large negative values of permittivity. Besides compensating for losses, the strong gain via QD can provide optical amplification with particular choices of the nanoshell and lattice dimensions.

  2. Types of gas fluidization of cohesive granular materials.

    Science.gov (United States)

    Valverde, Jose Manuel; Castellanos, Antonio

    2007-03-01

    Some years ago it was shown that gas-fluidized powders may transit from solid-like to fluid-like fluidization prior to bubbling, shedding light on a long-standing controversy on the nature of "homogeneous" fluidization. In this paper it is shown that some gas-fluidized powders may also transit from the fluid-like regime to elutriation, with full suppression of the bubbling regime. We provide a diagram that can be used to predict these types of fluidization exhibited by cohesive powders based on simple phenomenological equations in which particle aggregation due to attractive forces is a key ingredient.

  3. Drilling on Mars---Mathematical Model for Rotary-Ultrasonic Core Drilling of Brittle Materials

    Science.gov (United States)

    Horne, Mera Fayez

    The results from the Phoenix mission led scientists to believe it is possible that primitive life exists below the Martian surface. Therefore, drilling in Martian soil in search for organisms is the next logical step. Drilling on Mars is a major engineering challenge due to the drilling depth requirement. Mars lacks a thick atmosphere and a continuous magnetic field that shield the planet's surface from solar radiation and solar flares. As a result, the Martian surface is sterile and if life ever existed, it must be found below the surface. In 2001, NASA's Mars Exploration Payload Advisory Group proposed that drilling should be considered as a priority investigation on Mars in an effort of finding evidence of extinct or extant life. On August 6, 2012, the team of engineers landed the spacecraft Curiosity on the surface of Mars by using a revolutionary hovering platform. The results from the Curiosity mission suggested the next logical step, which is drilling six meters deep in the red planet in search of life. Excavation tools deployed to Mars so far have been able to drill to a maximum depth of 6.5 cm. Thus, the drilling capabilities need to be increased by a factor or approximately 100 to achieve the goal of drilling six meters deep. This requirement puts a demand on developing a new and more effective technologies to reach this goal. Previous research shows evidence of a promising drilling mechanism in rotary-ultrasonic for what it offers in terms of high surface quality, faster rate of penetration and higher material removal rate. This research addresses the need to understand the mechanics of the drill bit tip and rock interface in rotary-ultrasonic drilling of brittle materials. A mathematical model identifying all contributing independent parameters, such as drill bit design parameters, drilling process parameters, ultrasonic wave amplitude and rocks' material properties, that have effect on rate of penetration is developed. Analytical and experimental

  4. Alloying design of oxide dispersion strengthened ferritic steel for long life FBRs core materials

    Science.gov (United States)

    Ukai, S.; Harada, M.; Okada, H.; Inoue, M.; Nomura, S.; Shikakura, S.; Asabe, K.; Nishida, T.; Fujiwara, M.

    1993-09-01

    Oxide dispersion strengthened (ODS) ferritic steels with excellent swelling resistance and superior high temperature strength are prospective cladding materials for advanced fast breeder reactors. The addition of Ti in 13Cr-3W ODS ferritic steels improved the high temperature strength remarkably by the formation of uniformly distributed ultra-fine oxide particles. ODS ferritic steels have a bamboo-like grain structure and a strong deformation texture. The decrease of creep rupture strength in the bi-axial direction compared to the uni-axial direction is attributed mainly to this unique bamboo grain structure. Nearly equivalent creep rupture strength for both bi-axial and uni-axial direction was successfully attained by introducing the α to γ transformation in ODS martensitic steel.

  5. Built-up Effect of Core Material for Microencapsulated Flame Retardant Containing Dimethyl Methyl Phosphate

    Institute of Scientific and Technical Information of China (English)

    LIN Miao; DONG Kai; YANG Yong

    2008-01-01

    The flame retardants containing organophosphorus compounds have extensively been used inthe flame retarding of polymer materials.Among others,dimethyl methyl phosphate (DMMP) was applied in flame retarding of polyurethane owmg to its so much merit.However,the water-soluble property of DMMP restricted its application in textile fabric.The flame retardtag systemcontainirm DMMP will be microencapsulated to form a novel flame retardant that could be used in textiles.We have studied the builtup effect of DMMP with some inorganic compounds to improve the afterflame and afterglow suppression in the flame retarding system.The experimeatal data indicated that inorganic compounds containing various non-metal elements P,N,B and metal ions Mg2+,Al3+,Ca2+,Zn2+,Cu2+,Mn4+ could be applied in flame retarding systems as additives to effectively suppress afterflame or afterglow.

  6. 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.

  7. Self-Assembly of Crystalline Structures of Magnetic Core-Shell Nanoparticles for Fabrication of Nanostructured Materials.

    Science.gov (United States)

    Xue, Xiaozheng; Wang, Jianchao; Furlani, Edward P

    2015-10-14

    A theoretical study is presented of the template-assisted formation of crystalline superstructures of magnetic-dielectric core-shell particles. The templates produce highly localized gradient fields and a corresponding magnetic force that guides the assembly with nanoscale precision in particle placement. The process is studied using two distinct and complementary computational models that predict the dynamics and energy of the particles, respectively. Both mono- and polydisperse colloids are studied, and the analysis demonstrates for the first time that although the particles self-assemble into ordered crystalline superstructures, the particle formation is not unique. There is a Brownian motion-induced degeneracy in the process wherein various distinct, energetically comparable crystalline structures can form for a given template geometry. The models predict the formation of hexagonal close packed (HCP) and face centered cubic (FCC) structures as well as mixed phase structures due to in-plane stacking disorders, which is consistent with experimental observations. The polydisperse particle structures are less uniform than the monodisperse particle structures because of the irregular packing of different-sized particles. A comparison of self-assembly using soft- and hard-magnetic templates is also presented, the former being magnetized in a uniform field. This analysis shows that soft-magnetic templates enable an order-of-magnitude more rapid assembly and much higher spatial resolution in particle placement than their hard-magnetic counterparts. The self-assembly method discussed is versatile and broadly applies to arbitrary template geometries and multilayered and multifunctional mono- and polydisperse core-shell particles that have at least one magnetic component. As such, the method holds potential for the bottom-up fabrication of functional nanostructured materials for a broad range of applications. This work provides unprecedented insight into the assembly

  8. The Political Economy of Raw Materials Transport from Internal Periphery to Core in the Early 20th Century US: The Calumet & Hecla Copper Company’s Struggle for Market Access, 1922–39

    Directory of Open Access Journals (Sweden)

    Jonathan Leitner

    2015-08-01

    Full Text Available The Calumet & Hecla Copper Company was a firm funded by core capital, but operating in an internal periphery (Michigan’s Upper Peninsula, and eventually subject to peripheral constraints, along with the constraints of the physical environment, the physical characteristics of copper, and a concentrating industrial structure itself due largely to the physical characteristics of other types of copper mined elsewhere in the world. I focus on the firm’s efforts to maintain market access in the face of both a restructuring copper industry, driven by the coming online of much larger, lower-grade deposits that required much larger aggregations of capital to extract and process; and a restructuring transport system, driven by copper’s industrial restructuring, but also by the politics of core and periphery within the U.S., including the imperatives of transport capital that tied peripheral resources to core manufacturing industry. A number of world-systems works over the past decade have examined periphery-core resource transport, exploring its importance to historical capitalism via increasing the speed and scope of circulation, improving access to raw materials, and being a leading sector for rising hegemons, due to the ever-increasing need for raw materials entailed by economic ascent. The case examined here was part of the United States’ own core emergence and eventual hegemonic ascendance, which was largely based on its domestic raw materials and the internal transport lines that enabled core industry to gain cheap access to those resources.

  9. Synthesis of Reabsorption-Suppressed Type-II/Type-I ZnSe/CdS/ZnS Core/Shell Quantum Dots and Their Application for Immunosorbent Assay

    Science.gov (United States)

    Wang, Sheng; Li, Jin Jie; Lv, Yanbing; Wu, Ruili; Xing, Ming; Shen, Huaibin; Wang, Hongzhe; Li, Lin Song; Chen, Xia

    2017-06-01

    We report a phosphine-free one-pot method to synthesize ZnSe/CdS/ZnS core-shell quantum dots (QDs) with composite type-II/type-I structures and consequent reabsorption suppression properties. The as-synthesized QDs possess high efficient red emission (with quantum yield of 82%) and high optical stability. Compared to type-I QDs, the ZnSe/CdS/ZnS QDs show larger Stokes shift and lower reabsorption which can reduce the emission loss and improve the level of fluorescence output. The ZnSe/CdS/ZnS QDs are used as fluorescent labels to exploit their application in fluorescence-linked immunosorbent assay (FLISA) for the first time in the detection of C-reactive protein (CRP) with a limit of detection (LOD) of 0.85 ng/mL, which is more sensitive than that of CdSe/ZnS type-I QDs based FLISA (1.00 ng/mL). The results indicate that the ZnSe/CdS/ZnS type-II/type-I QDs may be good candidates for applications in biomedical information detection.

  10. Type 1 Interferons Induce Changes in Core Metabolism that Are Critical for Immune Function.

    Science.gov (United States)

    Wu, Duojiao; Sanin, David E; Everts, Bart; Chen, Qiongyu; Qiu, Jing; Buck, Michael D; Patterson, Annette; Smith, Amber M; Chang, Chih-Hao; Liu, Zhiping; Artyomov, Maxim N; Pearce, Erika L; Cella, Marina; Pearce, Edward J

    2016-06-21

    Greater understanding of the complex host responses induced by type 1 interferon (IFN) cytokines could allow new therapeutic approaches for diseases in which these cytokines are implicated. We found that in response to the Toll-like receptor-9 agonist CpGA, plasmacytoid dendritic cells (pDC) produced type 1 IFNs, which, through an autocrine type 1 IFN receptor-dependent pathway, induced changes in cellular metabolism characterized by increased fatty acid oxidation (FAO) and oxidative phosphorylation (OXPHOS). Direct inhibition of FAO and of pathways that support this process, such as fatty acid synthesis, prevented full pDC activation. Type 1 IFNs also induced increased FAO and OXPHOS in non-hematopoietic cells and were found to be responsible for increased FAO and OXPHOS in virus-infected cells. Increased FAO and OXPHOS in response to type 1 IFNs was regulated by PPARα. Our findings reveal FAO, OXPHOS and PPARα as potential targets to therapeutically modulate downstream effects of type 1 IFNs.

  11. The effect of core material, veneering porcelain, and fabrication technique on the biaxial flexural strength and weibull analysis of selected dental ceramics.

    Science.gov (United States)

    Lin, Wei-Shao; Ercoli, Carlo; Feng, Changyong; Morton, Dean

    2012-07-01

    The objective of this study was to compare the effect of veneering porcelain (monolithic or bilayer specimens) and core fabrication technique (heat-pressed or CAD/CAM) on the biaxial flexural strength and Weibull modulus of leucite-reinforced and lithium-disilicate glass ceramics. In addition, the effect of veneering technique (heat-pressed or powder/liquid layering) for zirconia ceramics on the biaxial flexural strength and Weibull modulus was studied. Five ceramic core materials (IPS Empress Esthetic, IPS Empress CAD, IPS e.max Press, IPS e.max CAD, IPS e.max ZirCAD) and three corresponding veneering porcelains (IPS Empress Esthetic Veneer, IPS e.max Ceram, IPS e.max ZirPress) were selected for this study. Each core material group contained three subgroups based on the core material thickness and the presence of corresponding veneering porcelain as follows: 1.5 mm core material only (subgroup 1.5C), 0.8 mm core material only (subgroup 0.8C), and 1.5 mm core/veneer group: 0.8 mm core with 0.7 mm corresponding veneering porcelain with a powder/liquid layering technique (subgroup 0.8C-0.7VL). The ZirCAD group had one additional 1.5 mm core/veneer subgroup with 0.7 mm heat-pressed veneering porcelain (subgroup 0.8C-0.7VP). The biaxial flexural strengths were compared for each subgroup (n = 10) according to ISO standard 6872:2008 with ANOVA and Tukey's post hoc multiple comparison test (p≤ 0.05). The reliability of strength was analyzed with the Weibull distribution. For all core materials, the 1.5 mm core/veneer subgroups (0.8C-0.7VL, 0.8C-0.7VP) had significantly lower mean biaxial flexural strengths (p strength (p= 0.004) than subgroup 0.8C-0.7VP. Nonetheless, both veneered ZirCAD groups showed greater flexural strength than the monolithic Empress and e.max groups, regardless of core thickness and fabrication techniques. Comparing fabrication techniques, Empress Esthetic/CAD, e.max Press/CAD had similar biaxial flexural strength (p= 0.28 for Empress pair; p= 0

  12. Current limiting behavior in three-phase transformer-type SFCLs using an iron core according to variety of fault

    Science.gov (United States)

    Cho, Yong-Sun; Jung, Byung-Ik; Ha, Kyoung-Hun; Choi, Soo-Geun; Park, Hyoung-Min; Choi, Hyo-Sang

    To apply the superconducting fault current limiter (SFCL) to the power system, the reliability of the fault-current-limiting operation must be ensured in diverse fault conditions. The SFCL must also be linked to the operation of the high-speed recloser in the power system. In this study, a three-phase transformer-type SFCL, which has a neutral line to improve the simultaneous quench characteristics of superconducting elements, was manufactured to analyze the fault-current-limiting characteristic according to the single, double, and triple line-to-ground faults. The transformer-type SFCL, wherein three-phase windings are connected to one iron core, reduced the burden on the superconducting element as the superconducting element on the sound phase was also quenched in the case of the single line-to-ground fault. In the case of double or triple line-to-ground faults, the flux from the faulted phase winding was interlinked with other faulted or sound phase windings, and the fault-current-limiting rate decreased because the windings of three phases were inductively connected by one iron core.

  13. The type-material of Oriental and Australasian Muscidae (Diptera) in the Zoological Museum, Amsterdam

    NARCIS (Netherlands)

    Pont, Adrian C.

    1970-01-01

    The type-material of Oriental und Australasian Muscidae in the University Zoological Museum, Amsterdam, is discussed. Of 131 species considered, the primary types of 112 are located in Amsterdam, and the location of the other types is also listed. 40 lectotypes are designated and 19 new combinations

  14. The Comparison of Shear Bond Strength Between Fibre Reinforced Composite Posts with Three Different Composite Core Materials - An In vitro Study.

    Science.gov (United States)

    Anche, Sampath; Kakarla, Pranitha; Kadiyala, Krishna Kishore; Sreedevi, B; Chiramana, Sandeep; Dev J, Ravi Rakesh; Manne, Sanjay Dutt; G, Deepthi

    2014-01-01

    The aim of this study is to compare the shear bond strength between fiber reinforced composite post with three different composite core materials. The materials used for the study were: 30 maxillary central incisors, pre fabricated fiber reinforced composite post (postec plus posts), Multi-core heavy body, Ti-core, Fluoro-core, Etchant gel, Silane coupling agent, Dentin bonding agent, Standardized gutta percha points, Rely-X dual cure composite resin. A total of 30 human maxillary central incisor were selected for this study. They were divided into three groups of 10 specimens each namely A, B and C. The results obtained were analyzed by using one way analysis (ANOVA) and Tukey Honestly Significant Difference and they showed highest mean shear bond strength for group C when compared with group A and group B. There is no significant difference in the shear bond strength values between group A and group B. The teeth restored with multicore HB showed highest shear bond strength. The teeth restored with Fluoro core showed lowest shear bond strength. No statistically significant difference exists between the shear bond strength values between Ti-core and Fluoro-core.

  15. Design Optimization with Geometric Programming for Core Type Large Power Transformers

    Directory of Open Access Journals (Sweden)

    Orosz Tamás

    2014-10-01

    Full Text Available A good transformer design satisfies certain functions and requirements. We can satisfy these requirements by various designs. The aim of the manufacturers is to find the most economic choice within the limitations imposed by the constraint functions, which are the combination of the design parameters resulting in the lowest cost unit. One of the earliest application of the Geometric Programming [GP] is the optimization of power transformers. The GP formalism has two main advantages. First the formalism guarantees that the obtained solution is the global minimum. Second the new solution methods can solve even large-scale GPs extremely efficiently and reliably. The design optimization program seeks a minimum capitalized cost solution by optimally setting the transformer's geometrical and electrical parameters. The transformer's capitalized cost chosen for object function, because it takes into consideration the manufacturing and the operational costs. This paper considers the optimization for three winding, three phase, core-form power transformers. This paper presents the implemented transformer cost optimization model and the optimization results.

  16. SN 2012aa - a transient between Type Ibc core-collapse and superluminous supernovae

    CERN Document Server

    Roy, R; Silverman, J M; Pastorello, A; Fransson, C; Drake, A; Taddia, F; Fremling, C; Kankare, E; Kumar, B; Cappellaro, E; Bose, S; Benetti, S; Filippenko, A V; Valenti, S; Nyholm, A; Ergon, M; Sutaria, F; Kumar, B; Pandey, S B; Nicholl, M; Garcia-Alvarez, D; Tomasella, L; Karamehmetoglu, E; Migotto, K

    2016-01-01

    Context: Research on supernovae (SNe) over the past decade has confirmed that there is a distinct class of events which are much more luminous (by $\\sim2$ mag) than canonical core-collapse SNe (CCSNe). These events with visual peak magnitudes $\\lesssim-21$ are called superluminous SNe (SLSNe). Aims: There are a few intermediate events which have luminosities between these two classes. Here we study one such object, SN 2012aa. Methods: The optical photometric and spectroscopic follow-up observations of the event were conducted over a time span of about 120 days. Results: With V_abs at peak ~-20 mag, the SN is an intermediate-luminosity transient between regular SNe Ibc and SLSNe. It also exhibits an unusual secondary bump after the maximum in its light curve. We interpret this as a manifestation of SN-shock interaction with the CSM. If we would assume a $^{56}$Ni-powered ejecta, the bolometric light curve requires roughly 1.3 M_sun of $^{56}$Ni and an ejected mass of ~14 M_sun. This would also imply a high kin...

  17. Rapid construction of the tricyclic cores of the abietane- and icetexane-type diterpenoids

    Institute of Scientific and Technical Information of China (English)

    De Lin Chen; Xiao Yu Liu; Hang Cheng; Feng Peng Wang

    2011-01-01

    A short synthesis of the tricyclic 6-6-6 and 6-7-6 ring systems of the abietane- and icetexane-type diterpenoids from a common intermediate is presented, using alleyiation and acid-catalyzed cyclization as key steps.

  18. On the types and number of plane waves in hypoelastic materials

    Science.gov (United States)

    Rushchitsky, J. J.

    2005-11-01

    General principles are formulated for modeling the elastic deformation of materials and analyzing plane waves in nonlinearly elastic materials such as hyperelastic, hypoelastic, and those governed by the general law of elasticity. The results of studying the propagation of plane waves in hypoelastic materials are further outlined. The influence of initial stresses and initial velocities on the types and number of plane waves is studied. Wave effects characteristic of hypoelastic materials are predicted theoretically. One of such effects is blocking of certain types of plane waves by initial stresses

  19. ZnO nanorod/CdS nanocrystal core/shell-type heterostructures for solar cell applications

    Science.gov (United States)

    Guerguerian, Gariné; Elhordoy, Fernando; Pereyra, Carlos J.; Marotti, Ricardo E.; Martín, Francisco; Leinen, Dietmar; Ramos-Barrado, José R.; Dalchiele, Enrique A.

    2011-12-01

    ZnO/CdS core/shell nanorod arrays were fabricated by a two-step method. Single-crystalline ZnO nanorod arrays were first electrochemically grown on SnO2:F (FTO) glass substrates. Then, CdS nanocrystals were deposited onto the ZnO nanorods, using the successive ion layer adsorption and reaction (SILAR) technique, to form core/shell nanocable architectures. Structural, morphological and optical properties of the nanorod heterojunctions were investigated. The results indicate that CdS single-crystalline domains with a mean diameter of about 7 nm are uniformly and conformally covered on the surface of the single-crystalline ZnO nanorods. ZnO absorption with a bandgap energy value of 3.30 ± 0.02 eV is present in all optical transmittance spectra. Another absorption edge close to 500 nm corresponding to CdS with bandgap energy values between 2.43 and 2.59 eV is observed. The dispersion in this value may originate in quantum confinement inside the nanocrystalline material. The appearance of both edges corresponds with the separation of ZnO and CdS phases and reveals the absorption increase due to CdS sensitizer. The photovoltaic performance of the resulting ZnO/CdS core/shell nanorod arrays has been investigated as solar cell photoanodes in a photoelectrochemical cell under white illumination. In comparison with bare ZnO nanorod arrays, a 13-fold enhancement in photoactivity was observed using the ZnO/CdS coaxial heterostructures.

  20. Push-out bond strength and dentinal tubule penetration of different root canal sealers used with coated core materials.

    Science.gov (United States)

    Deniz Sungur, Derya; Purali, Nuhan; Coşgun, Erdal; Calt, Semra

    2016-05-01

    The aim of this study was to compare the push-out bond strength and dentinal tubule penetration of root canal sealers used with coated core materials and conventional gutta-percha. A total of 72 single-rooted human mandibular incisors were instrumented with NiTi rotary files with irrigation of 2.5% NaOCl. The smear layer was removed with 17% ethylenediaminetetraacetic acid (EDTA). Specimens were assigned into four groups according to the obturation system: Group 1, EndoRez (Ultradent Product Inc.); Group 2, Activ GP (Brasseler); Group 3, SmartSeal (DFRP Ltd. Villa Farm); Group 4, AH 26 (Dentsply de Trey)/gutta-percha (GP). For push-out bond strength measurement, two horizontal slices were obtained from each specimen (n = 20). To compare dentinal tubule penetration, remaining 32 roots assigned to 4 groups as above were obturated with 0.1% Rhodamine B labeled sealers. One horizontal slice was obtained from the middle third of each specimen (n = 8) and scanned under confocal laser scanning electron microscope. Tubule penetration area, depth, and percentage were measured. Kruskall-Wallis test was used for statistical analysis. EndoRez showed significantly lower push-out bond strength than the others (p strength and sealer penetration of resin-and glass ionomer-based sealers used with coated core was not superior to resin-based sealer used with conventional GP. Dentinal tubule penetration has limited effect on bond strength. The use of conventional GP with sealer seems to be sufficient in terms of push-out bond strength.

  1. Core Genome Multilocus Sequence Typing Scheme for Stable, Comparative Analyses of Campylobacter jejuni and C. coli Human Disease Isolates

    Science.gov (United States)

    Bray, James E.; Jolley, Keith A.; McCarthy, Noel D.

    2017-01-01

    ABSTRACT Human campylobacteriosis, caused by Campylobacter jejuni and C. coli, remains a leading cause of bacterial gastroenteritis in many countries, but the epidemiology of campylobacteriosis outbreaks remains poorly defined, largely due to limitations in the resolution and comparability of isolate characterization methods. Whole-genome sequencing (WGS) data enable the improvement of sequence-based typing approaches, such as multilocus sequence typing (MLST), by substantially increasing the number of loci examined. A core genome MLST (cgMLST) scheme defines a comprehensive set of those loci present in most members of a bacterial group, balancing very high resolution with comparability across the diversity of the group. Here we propose a set of 1,343 loci as a human campylobacteriosis cgMLST scheme (v1.0), the allelic profiles of which can be assigned to core genome sequence types. The 1,343 loci chosen were a subset of the 1,643 loci identified in the reannotation of the genome sequence of C. jejuni isolate NCTC 11168, chosen as being present in >95% of draft genomes of 2,472 representative United Kingdom campylobacteriosis isolates, comprising 2,207 (89.3%) C. jejuni isolates and 265 (10.7%) C. coli isolates. Validation of the cgMLST scheme was undertaken with 1,478 further high-quality draft genomes, containing 150 or fewer contiguous sequences, from disease isolate collections: 99.5% of these isolates contained ≥95% of the 1,343 cgMLST loci. In addition to the rapid and effective high-resolution analysis of large numbers of diverse isolates, the cgMLST scheme enabled the efficient identification of very closely related isolates from a well-defined single-source campylobacteriosis outbreak. PMID:28446571

  2. Full-length core sequence dependent complex-type glycosylation of hepatitis C virus E2 glycoprotein

    Institute of Scientific and Technical Information of China (English)

    Li-Xin Zhu; Jing Liu; Ying-Chun Li; Yu-Ying Kong; Caroline Staib; Gerd Sutter; Yuan Wang; Guang-Di Li

    2002-01-01

    AIM: To study HCV polyprotein processing is important forthe understanding of the natural history of HCV and thedesign of vaccines against HCV. The purpose of this studyis to investigate the affection of context sequences onhepatitis C virus (HCV) E2 processingMETHODS: HCV genes of different lengths were expressedand compared in vaccinia virus/T7 system with homologouspatient serum S94 and mouse anti-serum ME2116 raisedagainst E. coli-derived E2 peptide, respectively.Deglycosylation analysis and GNA (Galanthus nivalus )lectin binding assay were performed to study the post-translational processing of the expressed products.RESULTS: E2 glycoproteins with different molecular weights( ~ 75kDa end ~ 60kDa) were detected using S94 and ME2116,respectively. Deglycosylation analysis showed that thisdifference was mainly due to different glycosylation. Endo Hresistance and its failure to bind to GNA lectin demonstratedthat the higher molecular weight form (75kDa) of E2 wascomplex-type glycosylated, which was readily recognized byhomologous patient serum S94. Expression of complex-typeglycosylated E2 could not be detected in all of the core-truncated constructs tested, but readily detected inconstructs encoding full-length core sequences.CONCLUSION: The upstream conserved full-length corecoding sequence was required for the production of E2glycoproteins carrying complex-type N-glycans whichreacted strongly with homologous patient serum andtherefore possibly represented more mature forms of E2. Ascomplex-type N-glycans indicated modification by Golgienzymes, the results suggest that the presence of full-lengthcore might be critical for E1/E2 complex to leave ER. Ourdata may contribute to a better understanding of theprocessing of HCV structural proteins as well as HCVmorphogenesis.

  3. In vitro shear bond strength of Y-TZP ceramics to different core materials with the use of three primer/resin cement systems.

    Science.gov (United States)

    Al-Harbi, Fahad A; Ayad, Neveen M; Khan, Zahid A; Mahrous, Amr A; Morgano, Steven M

    2016-01-01

    Durability of the bond between different core materials and zirconia retainers is an important predictor of the success of a dental prosthesis. Nevertheless, because of its polycrystalline structure, zirconia cannot be etched and bonded to a conventional resin cement. The purpose of this in vitro study was to compare the effects of 3 metal primer/resin cement systems on the shear bond strength (SBS) of 3 core materials bonded to yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic retainers. Zirconia ceramic (Cercon) disks (5×3 mm) were airborne-particle abraded, rinsed, and air-dried. Disk-shaped core specimens (7×7 mm) that were prepared of composite resin, Ni-Cr, and zirconia were bonded to the zirconia ceramic disks by using one of 3 metal primer/cement systems: (Z-Prime Plus/BisCem, Zirconia Primer/Multilink Automix, or Clearfil Ceramic Primer/Clearfil SA). SBS was tested in a universal testing machine. Stereomicroscopy was used to evaluate the failure mode of debonded specimens. Data were analyzed using 2-way ANOVA and post hoc analysis using the Scheffe procedure (α=.05). Clearfil SA/Clearfil Ceramic Primer system with an Ni-Cr core yielded the highest SBS value (19.03 MPa), whereas the lowest SBS value was obtained when Multilink Automix/Zirconia Primer system was used with the zirconia core group (4.09 MPa). Differences in mean SBS values among the cement/primer groups were statistically significant, except for Clearfil SA and BisCem with both composite resin and zirconia cores. Differences in mean SBS values among the core subgroups were not statistically significant, except for zirconia core with BisCem, Multilink, and Clearfil SA. The predominant failure mode was adhesive, except for Clearfil SA and BisCem luting agents with composite resin cores, which displayed cohesive failure, and Multilink Automix with a composite resin, core as well as Clearfil SA with Ni-Cr cores, where the debonded specimens of each group displayed a mixed

  4. A New Type of Submerged-Arc Flux-Cored Wire Used for Hardfacing Continuous Casting Rolls%A New Type of Submerged-Arc Flux-Cored Wire Used for Hardfacing Continuous Casting Rolls

    Institute of Scientific and Technical Information of China (English)

    YANG Ke; ZHANG Zhi-xi; HU Wang-qin; BAO Ye-feng; JIANG Yong-feng

    2011-01-01

    It is expected that the welding hardfacing of continuous casting rolls has better welding performance and higher wear resistance. A new type of submerged-arc hardfacing flux-cored wire has been developed through nitrogen replacing part of carbon and addition of the nitrogen-fixing elements of niobium and titanium. And microstructure, degree of hardness and high-temperature wear resistance of its deposited metal samples were also investigated. It is found that the microstructure is martensite, residual austenite and carbonitride precipitates. As a result, the hardfacing metal with homogeneous distribution of very fine carbonitride particles had high hardness and excellent wear-re- sisting property during high-temperature wear, which could significantly extend the service life of continuous casting rolls.

  5. Adhesion to root canal dentine using one and two-step adhesives with dual-cure composite core materials.

    Science.gov (United States)

    Foxton, R M; Nakajima, M; Tagami, J; Miura, H

    2005-02-01

    The regional tensile bond strengths of two dual-cure composite resin core materials to root canal dentine using either a one or two-step self-etching adhesive were evaluated. Extracted premolar teeth were decoronated and their root canals prepared to a depth of 8 mm and a width of 1.4 mm. In one group, a one-step self-etching adhesive (Unifil Self-etching Bond) was applied to the walls of the post-space and light-cured for 10 s. After which, the post-spaces were filled with the a dual-cure composite resin (Unifil Core) and then half the specimens were light-cured for 60 s and the other half placed in darkness for 30 min. In the second group, a self-etching primer (ED Primer II) was applied for 30 s, followed by an adhesive resin (Clearfil Photo Bond), which was light-cured for 10 s. The post-spaces were filled with a dual-cure composite resin (DC Core) and then half the specimens were light-cured for 60 s and the other half placed in darkness for 30 min. Chemical-cure composite resin was placed on the outer surfaces of all the roots, which were then stored in water for 24 h. They were serially sliced perpendicular to the bonded interface into 8, 0.6 mm-thick slabs, and then transversely sectioned into beams, approximately 8 x 0.6 x 0.6 mm, for the microtensile bond strength test (muTBS). Data were divided into two (coronal/apical half of post-space) and analysed using three-way anova and Scheffe's test (P composite resins and curing strategies, there were no significant differences in muTBS between the coronal and apical regions (P > 0.05). In addition, both dual-cure composite resins exhibited no significant differences in muTBS irrespective of whether polymerization was chemically or photoinitiated (P > 0.05). Both dual-cure composite resins exhibited good bonding to root canal dentin, which was not dependent upon region or mode of polymerization.

  6. Highly efficient near-infrared light-emitting diodes by using type-II CdTe/CdSe core/shell quantum dots as a phosphor.

    Science.gov (United States)

    Shen, Huaibin; Zheng, Ying; Wang, Hongzhe; Xu, Weiwei; Qian, Lei; Yang, Yixing; Titov, Alexandre; Hyvonen, Jake; Li, Lin Song

    2013-11-29

    In this paper, we present an innovative method for the synthesis of CdTe/CdSe type-II core/shell structure quantum dots (QDs) using 'greener' chemicals. The PL of CdTe/CdSe type-II core/shell structure QDs ranges from 600 to 820 nm, and the as-synthesized core/shell structures show narrow size distributions and stable and high quantum yields (50–75%). Highly efficient near-infrared light-emitting diodes (LEDs) have been demonstrated by employing the CdTe/CdSe type-II core/shell QDs as emitters. The devices fabricated based on these type-II core/shell QDs show color-saturated near-infrared emission from the QD layers, a low turn-on voltage of 1.55 V, an external quantum efficiency (EQE) of 1.59%, and a current density and maximum radiant emittance of 2.1 × 10(3) mA cm−2 and 17.7 mW cm−2 at 8 V; it is the first report to use type-II core/shell QDs as near-infrared emitters and these results may offer a practicable platform for the realization of near-infrared QD-based light-emitting diodes, night-vision-readable displays, and friend/foe identification system.

  7. Analysis on Mineral Element Contents in Associated with Varietal Type in Core Collection of Yunnan Rice

    Institute of Scientific and Technical Information of China (English)

    ZENGYa-wen; LIUJia-fu; WANGLu-xiang; SHENShi-quan; LIZi-chao; WANGXiangkun; WENGuo-song; YANGZhong-yi

    2004-01-01

    Eight-element contents of 653 unpolished rice samples harvested from Xingping experiment farm, Yunnan Province under thc same ecological conditions were analyzed by ICP-AES method. The mineral elements content were closely related to low diversity, high-yielding, and multi-resistance breeding; The K, Mg, Ca and Mn content in high-yielding and resistant varieties were high, and other nutrients such as P, Fe, Zn and Cu were low, which was connected with the heredity and physiological mechanism of mineral nutrients. There is zonal distribution of mineral elements content from Yunnan rice, especially for P, Fe, Zn and Cu co-related with the diversity center, paddy versus upland, glutinous and non-glutinous, glumc-hair versus nuda, rice color, rice flavor, soft rice versus non-soft rice, but it did not find any association with indica-japonica types. The results supported the ecological variety group view of 5-grade taxonomic system "species-subspecies-ccological groups-ecological variety groups - varietal types" .

  8. A Comparative Evaluation of Effect of Different Chemical Solvents on the Shear Bond Strength of Glass Fiber reinforced Post to Core Material.

    Science.gov (United States)

    Sharma, Ashish; Samadi, Firoza; Jaiswal, Jn; Saha, Sonali

    2014-01-01

    To compare the effect of different chemical solvents on glass fiber reinforced posts and to study the effect of these solvents on the shear bond strength of glass fiber reinforced post to core material. This study was conducted to evaluate the effect of three chemical solvents, i.e. silane coupling agent, 6% H2O2 and 37% phosphoric acid on the shear bond strength of glass fiber post to a composite resin restorative material. The changes in post surface characteristics after different treatments were also observed, using scanning electron microscopy (SEM) and shear bond strength was analyzed using universal testing machine (UTM). Surface treatment with hydrogen peroxide had greatest impact on the post surface followed by 37% phosphoric acid and silane. On evaluation of the shear bond strength, 6% H2O2 exhibited the maximum shear bond strength followed in descending order by 37% phosphoric acid and silane respectively. The surface treatment of glass fiber post enhances the adhesion between the post and composite resin which is used as core material. Failure of a fiber post and composite resin core often occurs at the junction between the two materials. This failure process requires better characterization. How to cite this article: Sharma A, Samadi F, Jaiswal JN, Saha S. A Comparative Evaluation of Effect of Different Chemical Solvents on the Shear Bond Strength of Glass Fiber Reinforced Post to Core Material. Int J Clin Pediatr Dent 2014;7(3):192-196.

  9. Site investigation SFR. Rock type coding, overview geological mapping and identification of rock units and possible deformation zones in drill cores from the construction of SFR

    Energy Technology Data Exchange (ETDEWEB)

    Petersson, Jesper (Vattenfall Power Consultant AB, Stockholm (Sweden)); Curtis, Philip; Bockgaard, Niclas (Golder Associates AB (Sweden)); Mattsson, Haakan (GeoVista AB, Luleaa (Sweden))

    2011-01-15

    This report presents the rock type coding, overview lithological mapping and identification of rock units and possible deformation zones in drill cores from 32 boreholes associated with the construction of SFR. This work can be seen as complementary to single-hole interpretations of other older SFR boreholes earlier reported in /Petersson and Andersson 2010/: KFR04, KFR08, KFR09, KFR13, KFR35, KFR36, KFR54, KFR55, KFR7A, KFR7B and KFR7C. Due to deficiencies in the available material, the necessary activities have deviated somewhat from the established methodologies used during the recent Forsmark site investigations for the final repository for spent nuclear fuel. The aim of the current work has been, wherever possible, to allow the incorporation of all relevant material from older boreholes in the ongoing SFR geological modelling work in spite of the deficiencies. The activities include: - Rock type coding of the original geological mapping according to the nomenclature used during the preceding Forsmark site investigation. As part of the Forsmark site investigation such rock type coding has already been performed on most of the old SFR boreholes if the original geological mapping results were available. This earlier work has been complemented by rock type coding on two further boreholes: KFR01 and KFR02. - Lithological overview mapping, including documentation of (1) rock types, (2) ductile and brittle-ductile deformation and (3) alteration for drill cores from eleven of the boreholes for which no original geological borehole mapping was available (KFR31, KFR32, KFR34, KFR37,KFR38, KFR51, KFR69, KFR70, KFR71, KFR72 and KFR89). - Identification of possible deformation zones and merging of similar rock types into rock units. This follows SKB's established criteria and methodology of the geological Single-hole interpretation (SHI) process wherever possible. Deviations from the standard SHI process are associated with the lack of data, for example BIPS images

  10. The Influence of Material Type, Preparation Design, and Tooth Substrate on Fracture Resistance of Molar Onlays

    OpenAIRE

    Al Khalifah, Shahed Ali M.

    2016-01-01

    Tooth colored all ceramic restorations have been the treatment preference of many patients for esthetics and biocompatibility. This study aimed to test the fracture resistance of posterior ceramic onlays milled with computer-aided design and computer aided manufacturing (CAD/CAM) machines.The effects of material type, preparation design, and tooth substrate were evaluated using a full-block design. Ninety teeth were tested. Three different CAD/CAM ceramic onlay material types were included: a...

  11. Frontostriatal dysexecutive syndrome: a core cognitive feature of myotonic dystrophy type 2.

    Science.gov (United States)

    Peric, Stojan; Mandic-Stojmenovic, Gorana; Stefanova, Elka; Savic-Pavicevic, Dusanka; Pesovic, Jovan; Ilic, Vera; Dobricic, Valerija; Basta, Ivana; Lavrnic, Dragana; Rakocevic-Stojanovic, Vidosava

    2015-01-01

    The aim of this study was to assess cognitive status in a large group of patients with myotonic dystrophy type 2 (DM2) compared to type 1 (DM1) subjects matched for gender and age, using a comprehensive battery of neuropsychological tests. Thirty-four genetically confirmed adult DM2 patients were recruited and matched for gender and age with 34 adult-onset DM1 subjects. All patients underwent detailed classic pen and pencil neuropsychological investigation and also computerized automated battery-CANTAB. More than half of DM2 patients had abnormal results on executive tests [Intra/Extradimensional Set Shift (IED), Stockings of Cambridge (SOC)] and verbal episodic memory (Ray Auditory Verbal Learning Test). Regarding DM1, abnormal results in more than 50 % of subjects were achieved in even ten tests, including visuospatial, language, executive, cognitive screening and visual memory tests. Direct comparison between patient groups showed that lower percentage of DM2 patients had abnormal results on following tests: Addenbrooke's Cognitive Examination-Revised, Raven Standard Progressive Matrices, Block Design, copy and recall of Rey-Osterieth Complex Figure, number of categories and perseverative responses on Wisconsin Card Sorting Test and Boston Naming Test (p < 0.01), as well as Trail Making Test-B and Spatial Span (p < 0.05). Our results showed significant dysexecutive syndrome and certain impairment of episodic verbal memory in DM2 patients that are reflective of frontal (especially frontostriatal) and temporal lobe dysfunction. On the other hand, dysexecutive and visuospatial/visuoconstructional deficits predominate in DM1 which correspond to the frontal, parietal (and occipital) lobe dysfunction.

  12. Scandium-doped zinc cadmium oxide as a new stable n-type oxide thermoelectric material

    DEFF Research Database (Denmark)

    Han, Li; Christensen, Dennis Valbjørn; Bhowmik, Arghya

    2016-01-01

    Scandium-doped zinc cadmium oxide (Sc-doped ZnCdO) is proposed as a new n-type oxide thermoelectric material. The material is sintered in air to maintain the oxygen stoichiometry and avoid instability issues. The successful alloying of CdO with ZnO at a molar ratio of 1 : 9 significantly reduced...

  13. Development of Two New Types of Retroreflective Materials as Countermeasures to Urban Heat Islands

    Science.gov (United States)

    Sakai, Hideki; Iyota, Hiroyuki

    2017-09-01

    In this study, the side effects of high-reflective and ordinary retroreflective materials, used as countermeasures to urban heat islands, are discussed. In addition, two retroreflective materials are proposed in order to avoid these adverse effects. These materials could be applied to roads and building exteriors to reduce their heat absorption from solar radiation. The first proposed type is the directional retroreflective material, which reflects light only during summer; therefore, it reduces the cooling load in summer, reduces the heating load in winter, and prevents light pollution at night. However, its structure is complicated and fragile; thus, it is suited for small areas, such as roofs and walls. The second type is the rough-surface retroreflective material, which shows weak retroreflectivity but can withstand distortion; thus, it is suited for roads. These two types require little maintenance, because they have no moving parts. Hence, these materials would not experience any breakdown, which is a great advantage for roads and building materials. Combining high-reflective, ordinary retroreflective, directional retroreflective, and rough-surface retroreflective materials, and assigning each type to the appropriate application would form an advanced mitigation system against urban heat islands.

  14. Stress distributions in maxillary central incisors restored with various types of post materials and designs.

    Science.gov (United States)

    Madfa, A A; Kadir, M R Abdul; Kashani, J; Saidin, S; Sulaiman, E; Marhazlinda, J; Rahbari, R; Abdullah, B J J; Abdullah, H; Abu Kasim, N H

    2014-07-01

    Different dental post designs and materials affect the stability of restoration of a tooth. This study aimed to analyse and compare the stability of two shapes of dental posts (parallel-sided and tapered) made of five different materials (titanium, zirconia, carbon fibre and glass fibre) by investigating their stress transfer through the finite element (FE) method. Ten three-dimensional (3D) FE models of a maxillary central incisor restored with two different designs and five different materials were constructed. An oblique loading of 100 N was applied to each 3D model. Analyses along the centre of the post, the crown-cement/core and the post-cement/dentine interfaces were computed, and the means were calculated. One-way ANOVAs followed by post hoc tests were used to evaluate the effectiveness of the post materials and designs (p=0.05). For post designs, the tapered posts introduced significantly higher stress compared with the parallel-sided post (pmaterials, the highest level of stress was found for stainless steel, followed by zirconia, titanium, glass fibre and carbon fibre posts (p<0.05). The carbon and glass fibre posts reduced the stress distribution at the middle and apical part of the posts compared with the stainless steel, zirconia and titanium posts. The opposite results were observed at the crown-cement/core interface.

  15. Hydrothermal synthesis of high-quality type-II CdTe/CdSe core/shell quantum dots with dark red emission.

    Science.gov (United States)

    Liu, Ning; Yang, Ping

    2014-08-01

    A hydrothermal method was used to synthesize type-II CdTe/CdSe core/shell quantum dots (QDs) using the thilglycolic acid (TGA) capped CdTe QDs as cores, which show a number of advantages. Because of the spatial separation of carriers the low excited states of CdTe/CdSe QDs, they exhibit many novel properties that are fundamentally different from the type-I QDs. On the other hand, our experiment results show that the wave function of the hole of the exciton in the CdTe core extends well into the CdSe shell. The results also reveal that a thick shell can confine the electrons inside the particles and thereby improve the PL efficiency and prolong the lifetime of the core/shell QDs. We use the UV-vis absorption and fluorescence spectrum measurements on growing particles in detail. We found that the fluorescence of the CdTe/CdSe QDs was strongly dependent on the thick of the shell and size of the core as well as the unique type-II heterostructure, which make the type-II core/shell QDs more suitable in photovoltaic or photoconduction applications.

  16. DotU and VgrG, core components of type VI secretion systems, are essential for Francisella LVS pathogenicity.

    Directory of Open Access Journals (Sweden)

    Jeanette E Bröms

    Full Text Available The Gram-negative bacterium Francisella tularensis causes tularemia, a disease which requires bacterial escape from phagosomes of infected macrophages. Once in the cytosol, the bacterium rapidly multiplies, inhibits activation of the inflammasome and ultimately causes death of the host cell. Of importance for these processes is a 33-kb gene cluster, the Francisella pathogenicity island (FPI, which is believed to encode a type VI secretion system (T6SS. In this study, we analyzed the role of the FPI-encoded proteins VgrG and DotU, which are conserved components of type VI secretion (T6S clusters. We demonstrate that in F. tularensis LVS, VgrG was shown to form multimers, consistent with its suggested role as a trimeric membrane puncturing device in T6SSs, while the inner membrane protein DotU was shown to stabilize PdpB/IcmF, another T6SS core component. Upon infection of J774 cells, both ΔvgrG and ΔdotU mutants did not escape from phagosomes, and subsequently, did not multiply or cause cytopathogenicity. They also showed impaired activation of the inflammasome and marked attenuation in the mouse model. Moreover, all of the DotU-dependent functions investigated here required the presence of three residues that are essentially conserved among all DotU homologues. Thus, in agreement with a core function in T6S clusters, VgrG and DotU play key roles for modulation of the intracellular host response as well as for the virulence of F. tularensis.

  17. Assembly and stoichiometry of the core structure of the bacterial flagellar type III export gate complex.

    Science.gov (United States)

    Fukumura, Takuma; Makino, Fumiaki; Dietsche, Tobias; Kinoshita, Miki; Kato, Takayuki; Wagner, Samuel; Namba, Keiichi; Imada, Katsumi; Minamino, Tohru

    2017-08-01

    The bacterial flagellar type III export apparatus, which is required for flagellar assembly beyond the cell membranes, consists of a transmembrane export gate complex and a cytoplasmic ATPase complex. FlhA, FlhB, FliP, FliQ, and FliR form the gate complex inside the basal body MS ring, although FliO is required for efficient export gate formation in Salmonella enterica. However, it remains unknown how they form the gate complex. Here we report that FliP forms a homohexameric ring with a diameter of 10 nm. Alanine substitutions of conserved Phe-137, Phe-150, and Glu-178 residues in the periplasmic domain of FliP (FliPP) inhibited FliP6 ring formation, suppressing flagellar protein export. FliO formed a 5-nm ring structure with 3 clamp-like structures that bind to the FliP6 ring. The crystal structure of FliPP derived from Thermotoga maritia, and structure-based photo-crosslinking experiments revealed that Phe-150 and Ser-156 of FliPP are involved in the FliP-FliP interactions and that Phe-150, Arg-152, Ser-156, and Pro-158 are responsible for the FliP-FliO interactions. Overexpression of FliP restored motility of a ∆fliO mutant to the wild-type level, suggesting that the FliP6 ring is a functional unit in the export gate complex and that FliO is not part of the final gate structure. Copurification assays revealed that FlhA, FlhB, FliQ, and FliR are associated with the FliO/FliP complex. We propose that the assembly of the export gate complex begins with FliP6 ring formation with the help of the FliO scaffold, followed by FliQ, FliR, and FlhB and finally FlhA during MS ring formation.

  18. Defining and Evaluating a Core Genome Multilocus Sequence Typing Scheme for Whole-Genome Sequence-Based Typing of Klebsiella pneumoniae.

    Science.gov (United States)

    Zhou, Haijian; Liu, Wenbing; Qin, Tian; Liu, Chen; Ren, Hongyu

    2017-01-01

    At present, the most used methods for Klebsiella pneumoniae subtyping are multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). However, the discriminatory power of MLST could not meet the need for distinguishing outbreak and non-outbreak isolates and the PFGE is time-consuming and labor-intensive. A core genome multilocus sequence typing (cgMLST) scheme for whole-genome sequence-based typing of K. pneumoniae was developed for solving the disadvantages of these traditional molecular subtyping methods. Firstly, we used the complete genome of K. pneumoniae strain HKUOPLC as the reference genome and 907 genomes of K. pneumoniae download from NCBI database as original genome dataset to determine cgMLST target genes. A total of 1,143 genes were retained as cgMLST target genes. Secondly, we used 26 K. pneumoniae strains from a nosocomial infection outbreak to evaluate the cgMLST scheme. cgMLST enabled clustering of outbreak strains with <10 alleles difference and unambiguous separation from unrelated outgroup strains. Moreover, cgMLST revealed that there may be several sub-clones of epidemic ST11 clone. In conclusion, the novel cgMLST scheme not only showed higher discriminatory power compared with PFGE and MLST in outbreak investigations but also showed ability to reveal more population structure characteristics than MLST.

  19. Pd-Ir Core-Shell Nanocubes: A Type of Highly Efficient and Versatile Peroxidase Mimic.

    Science.gov (United States)

    Xia, Xiaohu; Zhang, Jingtuo; Lu, Ning; Kim, Moon J; Ghale, Kushal; Xu, Ye; McKenzie, Erin; Liu, Jiabin; Ye, Haihang

    2015-10-27

    Peroxidase mimics with dimensions on the nanoscale have received great interest as emerging artificial enzymes for biomedicine and environmental protection. While a variety of peroxidase mimics have been actively developed recently, limited progress has been made toward improving their catalytic efficiency. In this study, we report a type of highly efficient peroxidase mimic that was engineered by depositing Ir atoms as ultrathin skins (a few atomic layers) on Pd nanocubes (i.e., Pd-Ir cubes). The Pd-Ir cubes exhibited significantly enhanced efficiency, with catalytic constants more than 20- and 400-fold higher than those of the initial Pd cubes and horseradish peroxidase (HRP), respectively. As a proof-of-concept demonstration, the Pd-Ir cubes were applied to the colorimetric enzyme-linked immunosorbent assay (ELISA) of human prostate surface antigen (PSA) with a detection limit of 0.67 pg/mL, which is ∼110-fold lower than that of the conventional HRP-based ELISA using the same set of antibodies and the same procedure.

  20. Analysis of resin-dentin interface morphology and bond strength evaluation of core materials for one stage post-endodontic restorations.

    Science.gov (United States)

    Bitter, Kerstin; Gläser, Christin; Neumann, Konrad; Blunck, Uwe; Frankenberger, Roland

    2014-01-01

    Restoration of endodontically treated teeth using fiber posts in a one-stage procedure gains more popularity and aims to create a secondary monoblock. Data of detailed analyses of so called "post-and-core-systems" with respect to morphological characteristics of the resin-dentin interface in combination with bond strength measurements of fiber posts luted with these materials are scarce. The present study aimed to analyze four different post-and-core-systems with two different adhesive approaches (self-etch and etch-and-rinse). Human anterior teeth (n = 80) were endodontically treated and post space preparations and post placement were performed using the following systems: Rebilda Post/Rebilda DC/Futurabond DC (Voco) (RB), Luxapost/Luxacore Z/Luxabond Prebond and Luxabond A+B (DMG) (LC), X Post/Core X Flow/XP Bond and Self Cure Activator (Dentsply DeTrey) (CX), FRC Postec/MultiCore Flow/AdheSE DC (Ivoclar Vivadent) (MC). Adhesive systems and core materials of 10 specimens per group were labeled using fluorescent dyes and resin-dentin interfaces were analyzed using Confocal Laser Scanning Microscopy (CLSM). Bond strengths were evaluated using a push-out test. Data were analyzed using repeated measurement ANOVA and following post-hoc test. CLSM analyses revealed significant differences between groups with respect to the factors hybrid layer thickness (pstrength was significantly affected by core material (p = 0.001), location inside the root canal (pstrength compared to LC [14.2 (8.7) MPa] and RB [13.3 (3.7) MPa] (pstrengths inside the root canal were not affected by the adhesive approach of the post-and-core-system. All systems demonstrated homogenous hybrid layer formation and penetration into the dentinal tubules in spite of the complicating conditions for adhesion inside the root canal.

  1. Readily synthesized dopant-free hole transport materials with phenol core for stabilized mixed perovskite solar cells

    Science.gov (United States)

    Xue, Yuyuan; Wu, Ying; Li, Yuan

    2017-03-01

    With the dramatic development of the power conversion efficiency (PCE) of perovskite solar cells (PVSCs), device lifetime has become one of the extensive research interests and concerns. To enhance the device durability, developing high performance dopant-free hole transport materials (HTMs) is a promising strategy. Herein, two new C3-symmetric HTMs with phenol core, TCP-OH and TCP-OC8 are readily prepared and show ultra-wide energy band-gap and excellent film-formation property. PCEs of 16.97% and 15.28% are achieved with pristine TCP-OH and TCP-OC8 film as HTMs, respectively, even though their hole mobilities are as low as 10-6 cm2 V-1 s-1. Phenol acts as hole trap in traditional concept, however, TCP-OH shows higher hole mobility than that of TCP-OC8. Moreover, TCP-OH shows higher glass transition temperature and better matching band alignment than those of TCP-OC8. Phenol shows great potential as building block for HTMs as it is beneficial to enhance hole mobility of HTMs. Moreover, our study demonstrates an interesting viewpoint to design HTMs with the balance of hole mobility and electron blocking effect.

  2. Magnetic core test stand for energy loss and permeability measurements at a high constant magnetization rate and test results for nanocrystalline and ferrite materials.

    Science.gov (United States)

    Burdt, Russell; Curry, Randy D

    2008-09-01

    A test stand was developed to measure the energy losses and unsaturated permeability of toroidal magnetic cores, relevant to applications of magnetic switching requiring a constant magnetization rate of the order of 1-10 T/micros. These applications in pulsed power include linear induction accelerators, pulse transformers, and discharge switches. The test stand consists of a coaxial transmission line pulse charged up to 100 kV that is discharged into a magnetic core load. Suitable diagnostics measure the voltage across and the current through a winding on the magnetic core load, from which the energy losses and unsaturated permeability are calculated. The development of the test stand is discussed, and test results for ferrite CN20 and the nanocrystalline material Finemet FT-1HS are compared to demonstrate the unique properties of a nanocrystalline material. The experimental data are compared with published data in a similar parameter space to demonstrate the efficacy of the experimental methods.

  3. Design analysis of the molten core confinement within the reactor vessel in the case of severe accidents at nuclear power plants equipped with a reactor of the VVER type

    Science.gov (United States)

    Zvonaryov, Yu. A.; Budaev, M. A.; Volchek, A. M.; Gorbaev, V. A.; Zagryazkin, V. N.; Kiselyov, N. P.; Kobzar', V. L.; Konobeev, A. V.; Tsurikov, D. F.

    2013-12-01

    The present paper reports the results of the preliminary design estimate of the behavior of the core melt in vessels of reactors of the VVER-600 and VVER-1300 types (a standard optimized and informative nuclear power unit based on VVER technology—VVER TOI) in the case of beyond-design-basis severe accidents. The basic processes determining the state of the core melt in the reactor vessel are analyzed. The concept of molten core confinement within the vessel based on the idea of outside cooling is discussed. Basic assumptions and models, as well as the results of calculation of the interaction between molten materials of the core and the wall of the reactor vessel performed by means of the SOCRAT severe accident code, are presented and discussed. On the basis of the data obtained, the requirements on the operation of the safety systems are determined, upon the fulfillment of which there will appear potential prerequisites for implementing the concept of the confinement of the core melt within the reactor in cases of severe accidents at nuclear power plants equipped with VVER reactors.

  4. Capsid proteins from human immunodeficiency virus type 1 and simian immunodeficiency virus SIVmac can coassemble into mature cores of infectious viruses.

    Science.gov (United States)

    Chen, Jianbo; Pathak, Vinay K; Peng, Weiqun; Hu, Wei-Shau

    2008-09-01

    We have recently shown that the Gag polyproteins from human immunodeficiency virus type 1 (HIV-1) and HIV-2 can coassemble and functionally complement each other. During virion maturation, the Gag polyproteins undergo proteolytic cleavage to release mature proteins including capsid (CA), which refolds and forms the outer shell of a cone-shaped mature core. Less than one-half of the CA proteins present within the HIV-1 virion are required to form the mature core. Therefore, it is unclear whether the mature core in virions containing both HIV-1 and HIV-2 Gag consists of CA proteins from a single virus or from both viruses. To determine whether CA proteins from two different viruses can coassemble into mature cores of infectious viruses, we exploited the specificity of the tripartite motif 5alpha protein from the rhesus monkey (rhTRIM5alpha) for cores containing HIV-1 CA (hCA) but not the simian immunodeficiency virus SIV(mac) CA protein (sCA). If hCA and sCA cannot coassemble into the same core when equal amounts of sCA and hCA are coexpressed, the infectivities of such virus preparations in cells should be inhibited less than twofold by rhTRIM5alpha. However, if hCA and sCA can coassemble into the same core structure to form a mixed core, rhTRIM5alpha would be able to recognize such cores and significantly restrict virus infectivity. We examined the restriction phenotypes of viruses containing both hCA and sCA. Our results indicate that hCA and sCA can coassemble into the same mature core to produce infectious virus. To our knowledge, this is the first demonstration of functional coassembly of heterologous CA protein into the retroviral core.

  5. Surface detail reproduction of Type IV dental stones with selected polyvinyl siloxane impression materials.

    Science.gov (United States)

    Schelb, E; Cavazos, E; Troendle, K B; Prihoda, T J

    1991-01-01

    Four polyvinyl siloxane impression materials and 14 modified Type IV dental stones were evaluated for their abilities to reproduce surface detail. Each combination of impression material and dental stone was used to duplicate a 20-microns-wide line. Surface detail reproduction was observed by two paired-rater groups. The line was reproduced in all impression material specimens, but in only 32% of the stone cast specimens. Some combinations of impression material/dental stone reproduced the line all or most of the time, but 12 combinations did not reproduce the line at all.

  6. Selective-Area MOCVD Growth and Carrier-Transport-Type Control of InAs(Sb)/GaSb Core-Shell Nanowires.

    Science.gov (United States)

    Ji, Xianghai; Yang, Xiaoguang; Du, Wenna; Pan, Huayong; Yang, Tao

    2016-12-14

    We report the first selective-area growth of high quality InAs(Sb)/GaSb core-shell nanowires on Si substrates using metal-organic chemical vapor deposition (MOCVD) without foreign catalysts. Transmission electron microscopy (TEM) analysis reveals that the overgrowth of the GaSb shell is highly uniform and coherent with the InAs(Sb) core without any misfit dislocations. To control the structural properties and reduce the planar defect density in the self-catalyzed InAs core nanowires, a trace amount of Sb was introduced during their growth. As the Sb content increases from 0 to 9.4%, the crystal structure of the nanowires changes from a mixed wurtzite (WZ)/zinc-blende (ZB) structure to a perfect ZB phase. Electrical measurements reveal that both the n-type InAsSb core and p-type GaSb shell can work as active carrier transport channels, and the transport type of core-shell nanowires can be tuned by the GaSb shell thickness and back-gate voltage. This study furthers our understanding of the Sb-induced crystal-phase control of nanowires. Furthermore, the high quality InAs(Sb)/GaSb core-shell nanowire arrays obtained here pave the foundation for the fabrication of the vertical nanowire-based devices on a large scale and for the study of fundamental quantum physics.

  7. Defining and Evaluating a Core Genome Multilocus Sequence Typing Scheme for Whole-Genome Sequence-Based Typing of Listeria monocytogenes.

    Science.gov (United States)

    Ruppitsch, Werner; Pietzka, Ariane; Prior, Karola; Bletz, Stefan; Fernandez, Haizpea Lasa; Allerberger, Franz; Harmsen, Dag; Mellmann, Alexander

    2015-09-01

    Whole-genome sequencing (WGS) has emerged today as an ultimate typing tool to characterize Listeria monocytogenes outbreaks. However, data analysis and interlaboratory comparability of WGS data are still challenging for most public health laboratories. Therefore, we have developed and evaluated a new L. monocytogenes typing scheme based on genome-wide gene-by-gene comparisons (core genome multilocus the sequence typing [cgMLST]) to allow for a unique typing nomenclature. Initially, we determined the breadth of the L. monocytogenes population based on MLST data with a Bayesian approach. Based on the genome sequence data of representative isolates for the whole population, cgMLST target genes were defined and reappraised with 67 L. monocytogenes isolates from two outbreaks and serotype reference strains. The Bayesian population analysis generated five L. monocytogenes groups. Using all available NCBI RefSeq genomes (n = 36) and six additionally sequenced strains, all genetic groups were covered. Pairwise comparisons of these 42 genome sequences resulted in 1,701 cgMLST targets present in all 42 genomes with 100% overlap and ≥90% sequence similarity. Overall, ≥99.1% of the cgMLST targets were present in 67 outbreak and serotype reference strains, underlining the representativeness of the cgMLST scheme. Moreover, cgMLST enabled clustering of outbreak isolates with ≤10 alleles difference and unambiguous separation from unrelated outgroup isolates. In conclusion, the novel cgMLST scheme not only improves outbreak investigations but also enables, due to the availability of the automatically curated cgMLST nomenclature, interlaboratory exchange of data that are crucial, especially for rapid responses during transsectorial outbreaks.

  8. Research of Core Wall Rock-fill Dam Anti-seepage Core Wall Materials in Lianghekou Hydropower Station%两河口水电站心墙堆石坝防渗心墙料的研究

    Institute of Scientific and Technical Information of China (English)

    欧阳学金

    2014-01-01

    Rock-fill-dam-of-Lianghekou-Hydropower-Station-Project-is-as-high-as-295-m.Gravel-soil-core-wall-material-of-4.29-million-m3-is-adopted.Since-the-rock-fill-dam-in-the-project-reaches-300m-grade,there-is-no-successful-construction-experience-in-China.Besides,impervious-soil-materials-are-widely-distributed,and-material-sources-are-complex.The-reasonability-and-reliability-of-the-core-wall-are-discussed-through-studying-anti-seepage-core-wall,thereby-providing-reference-for-studying-similar-dam-cor-wall-materials.%两河口水电站工程堆石坝坝高295m,砾石土心墙料429万m3。由于该工程堆石坝高达300m级,国内尚无建设的成功经验,而且防渗土料分布较广,料源复杂。本文通过对防渗心墙的研究,论证了其合理性和可靠性,为同类型大坝心墙料的研究提供参考。

  9. IRBIT Interacts with the Catalytic Core of Phosphatidylinositol Phosphate Kinase Type Iα and IIα through Conserved Catalytic Aspartate Residues.

    Directory of Open Access Journals (Sweden)

    Hideaki Ando

    Full Text Available Phosphatidylinositol phosphate kinases (PIPKs are lipid kinases that generate phosphatidylinositol 4,5-bisphosphate (PI(4,5P2, a critical lipid signaling molecule that regulates diverse cellular functions, including the activities of membrane channels and transporters. IRBIT (IP3R-binding protein released with inositol 1,4,5-trisphosphate is a multifunctional protein that regulates diverse target proteins. Here, we report that IRBIT forms signaling complexes with members of the PIPK family. IRBIT bound to all PIPK isoforms in heterologous expression systems and specifically interacted with PIPK type Iα (PIPKIα and type IIα (PIPKIIα in mouse cerebellum. Site-directed mutagenesis revealed that two conserved catalytic aspartate residues of PIPKIα and PIPKIIα are involved in the interaction with IRBIT. Furthermore, phosphatidylinositol 4-phosphate, Mg2+, and/or ATP interfered with the interaction, suggesting that IRBIT interacts with catalytic cores of PIPKs. Mutations of phosphorylation sites in the serine-rich region of IRBIT affected the selectivity of its interaction with PIPKIα and PIPKIIα. The structural flexibility of the serine-rich region, located in the intrinsically disordered protein region, is assumed to underlie the mechanism of this interaction. Furthermore, in vitro binding experiments and immunocytochemistry suggest that IRBIT and PIPKIα interact with the Na+/HCO3- cotransporter NBCe1-B. These results suggest that IRBIT forms signaling complexes with PIPKIα and NBCe1-B, whose activity is regulated by PI(4,5P2.

  10. LANMAS core: Update and current directions

    Energy Technology Data Exchange (ETDEWEB)

    Claborn, J. [Los Alamos National Lab., NM (United States). Safeguards Systems Group; Alvarado, A. [Sandia National Labs., Albuquerque, NM (United States)

    1994-08-01

    Local Area Network Material Accountability System (LANMAS) core software will provide the framework of a material accountability system. LANMAS is a network-based nuclear material accountability system. It tracks the movement of material throughout a site and generates the required reports on material accountability. LANMAS will run in a client/server mode. The database of material type and location will reside on the server, while the user interface runs on the client. The user interface accesses the server via a network. The LANMAS core can be used as the foundation for building required Materials Control and Accountability (MC&A) functionality at any site requiring a new MC&A system. An individual site will build on the LANMAS core by supplying site-specific software. This paper will provide an update on the current LANMAS development activities and discuss the current direction of the LANMAS project.

  11. Influence of core thickness and artificial aging on the biaxial flexural strength of different all-ceramic materials: An in-vitro study.

    Science.gov (United States)

    Dikicier, Sibel; Ayyildiz, Simel; Ozen, Julide; Sipahi, Cumhur

    2017-05-31

    The purpose of this study was to investigate the flexural strength of all-ceramics with varying core thicknesses submitted to aging. In-Ceram Alumina (IC), IPS e.max Press (EM) and Katana (K) (n=40), were selected. Each group contained two core groups based on the core thickness as follows: IC/0.5, IC/0.8, EM/0.5, EM/0.8, K/0.5 and K/0.8 mm in thickness (n=20 each). Ten specimens from each group were subjected to aging and all specimens were tested for strength in a testing machine either with or without being subjected aging. The mean strength of the K were higher (873.05 MPa) than that of the IC (548.28 MPa) and EM (374.32 MPa) regardless of core thickness. Strength values increased with increasing core thickness for all IC, EM and K regardless of aging. Results of this study concluded that strength was not significantly affected by aging. Different core thicknesses affected strength of the all-ceramic materials tested (p<0.05).

  12. The reactor core TRIGA Mark-III with fuels type 30/20; El nucleo del reactor TRIGA Mark-III con combustible tipo 30/20

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar H, F., E-mail: fortunato.aguilar@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2012-10-15

    This work describes the calculation series carried out with the program MCNP5 in order to define the configuration of the reactor core with fuels 30/20 (fuels with 30% of uranium content in the Or-Zr-H mixture and a nominal enrichment of 20%). To select the configuration of the reactor core more appropriate to the necessities and future uses of the reactor, the following criterions were taken into account: a) the excess in the reactor reactivity, b) the switch out margin and c) to have new irradiation facilities inside the reactor core. Taking into account these criterions is proceeded to know the characteristics of the components that form the reactor core (dimensions, geometry, materials, densities and positions), was elaborated a base model of the reactor core, for the MCNP5 code, with a configuration composed by 85 fuel elements, 4 control bars and the corresponding structural elements. The high reactivity excess obtained with this model, gave the rule to realize other models of the reactor core in which the reactivity excess and the switch out margin were approximate to the values established in the technical specifications of the reactor operation. Several models were realized until finding the satisfactory model; this is composite for 74 fuels, 4 control bars and 6 additional experimental positions inside the reactor core. (Author)

  13. A Core-Shell Fe/Fe2 O3 Nanowire as a High-Performance Anode Material for Lithium-Ion Batteries.

    Science.gov (United States)

    Na, Zhaolin; Huang, Gang; Liang, Fei; Yin, Dongming; Wang, Limin

    2016-08-16

    The preparation of novel one-dimensional core-shell Fe/Fe2 O3 nanowires as anodes for high-performance lithium-ion batteries (LIBs) is reported. The nanowires are prepared in a facile synthetic process in aqueous solution under ambient conditions with subsequent annealing treatment that could tune the capacity for lithium storage. When this hybrid is used as an anode material for LIBs, the outer Fe2 O3 shell can act as an electrochemically active material to store and release lithium ions, whereas the highly conductive and inactive Fe core functions as nothing more than an efficient electrical conducting pathway and a remarkable buffer to tolerate volume changes of the electrode materials during the insertion and extraction of lithium ions. The core-shell Fe/Fe2 O3 nanowire maintains an excellent reversible capacity of over 767 mA h g(-1) at 500 mA g(-1) after 200 cycles with a high average Coulombic efficiency of 98.6 %. Even at 2000 mA g(-1) , a stable capacity as high as 538 mA h g(-1) could be obtained. The unique composition and nanostructure of this electrode material contribute to this enhanced electrochemical performance. Due to the ease of large-scale fabrication and superior electrochemical performance, these hybrid nanowires are promising anode materials for the next generation of high-performance LIBs.

  14. One-step synthesis of metal@titania core-shell materials for visible-light photocatalysis and catalytic reduction reaction.

    Science.gov (United States)

    Xiong, Zhigang; Zhang, Luhong; Zhao, Xiu Song

    2014-11-03

    Metal@TiO2 composites with a core-shell structure possess multifunctional properties. The demonstrated protocols for synthesizing such materials involve multiple steps, requiring precise control over the particle uniformity of the core and shell thickness, as well as complex surface modification. A simple approach to synthesizing metal@TiO2 hybrid nanostructures remains a great challenge. Herein, we report on a one-step method for the preparation of metal@TiO2 core-shell nanospheres, which exhibited excellent performance in photocatalytic degradation of recalcitrant organic pollutants under visible light irradiation, and in catalytic reduction of nitrophenol in water. The simple method described here represents a sustainable approach to preparing core-shell materials at low cost, involving fewer chemicals, and requiring less energy, which will make a significant contribution toward large-scale synthesis of high-performance hybrid materials for photocatalytic applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Hepatitis C virus core protein induces energy metabolism disorders of hepatocytes by down-regulation of silent mating type information regulation 2 homolog-1 and adenosine monophosphate-acti vated protein kinase signaling pathway

    Institute of Scientific and Technical Information of China (English)

    于建武

    2013-01-01

    Objective To study the role of silent mating type information regulation2homotog-1(SIRT1)-adenosine monophosphate(AMP)-activated protein kinase(AMPK) signaling pathway in hepatitis C virus core protein(HCV-core)induced energy metabolism disorders

  16. Corrosion resistance of the composite materials: nanocrystalline powder – polymer type in acid environment

    Directory of Open Access Journals (Sweden)

    B. Ziębowicz

    2009-10-01

    Full Text Available Purpose: The paper presents corrosion resistance of composite materials Fe73.5Cu1Nb3Si13.5B9 – PEHD type in sulphuric acid and hydrochloric acid environments.Design/methodology/approach: Composite materials Fe73.5Cu1Nb3Si13.5B9 – PEHD type were manufactured by one-sided uniaxal pressing. The amount of polymer matrix was 2.5%, 5.0%, 7.5%, wt. Powder of the Fe73.5Cu1Nb3Si13.5B9 was made by the high-energy grinding in the shaker type 8000SPEX CertiPrep Mixer/Mill for 1 h, 3 h, 5 h. Composite materials were placed in a corrosive environment and two tests were carried out as specified below: test at the temperature of 25°C, 0.1 M solution of hydrochloric acid HCl, time 348 h; test temperature 25°C, 0.1 M solution of sulphuric acid H2SO4, time 348 h, test temperature 25°C.Findings: Obtained results of corrosion resistance allow to evaluate corrosion wear of composite materials FINEMET (Fe73.5Cu1Nb3Si13.5B9 – PEHD in acidic solutions of 0.1M HCl and 0.1M H2SO4. It was found that the composite materials with 7.5% wt. of polyethylene portion show the best corrosion resistance.Research limitations/implications: Composite materials Fe73.5Cu1Nb3Si13.5B9– PEHD type manufacturing greatly expand the application possibilities of soft magnetic materials nanocrystalline powders however further examination to obtain improved properties of magnetic composite materials and investigations of new machines and devices constructions with these materials elements are still needed.Originality/value: Results allow to complete data concerning composite materials nanocrystalline powder – polymer type which are an attractive alternative for traditional materials with specific magnetic properties. Results are the base for further investigations of the impact of corrosion environment on the magnetic properties such composite materials.

  17. Analysis of the In-core Quadrant Power Tilt affected by Burned Fuel Shuffles of WEC Type NPPs in Republic of Korea

    Energy Technology Data Exchange (ETDEWEB)

    Son, Seung-beom; Jeon, Jeong-pyo; Song, Han-seung; Seong, Ki-bong; Lim, Chae-joon [KEPCO Nuclear Fuel, Daejeon (Korea, Republic of)

    2016-10-15

    This paper presents the designed Burned Fuel Shuffles (BFS) and the related results of measured In-core Quadrant Power Tilt (IQPT) in recent cycles of WEC (Westinghouse Electric Company) type NPPs (Nuclear Power Plants) in Republic of Korea. And the IQPT sensitivity results affected by BFS are also analyzed. Excessive core Quadrant Power Tilt (QPT) causes unreliability about designed power distribution and increases peaking factors in the affected core quadrants. The peaking factors are under surveillance during the cycle for the safe operation and the Quadrant Power Tilt Ratio (QPTR) is covered by the Technical Specifications. Possible causes for QPT include manufacturing tolerance, asymmetric core configurations, operating conditions, and so forth, but the actual cause of specific core tilts frequently cannot be definitively identified. But nuclear designer continuously try to minimize the QPT by the general control of burned fuel distribution in a reload core. In this study, the general guidelines of BFSP for effective mitigation of IQPT were introduced by references and the actual states of designed BFSP were analyzed for WEC type plant operating in the Republic of Korea. Results revealed that the BFSP was applied within appropriate level, which keeps IQPT below the level of guideline during the operations. Also, the correlation between BFSP of category 1/3 and IQPT were quantitatively confirmed by the sensitivity analysis concerned with the change of BFSP.

  18. Recent Developments in p-Type Oxide Semiconductor Materials and Devices

    KAUST Repository

    Wang, Zhenwei

    2016-02-16

    The development of transparent p-type oxide semiconductors with good performance may be a true enabler for a variety of applications where transparency, power efficiency, and greater circuit complexity are needed. Such applications include transparent electronics, displays, sensors, photovoltaics, memristors, and electrochromics. Hence, here, recent developments in materials and devices based on p-type oxide semiconductors are reviewed, including ternary Cu-bearing oxides, binary copper oxides, tin monoxide, spinel oxides, and nickel oxides. The crystal and electronic structures of these materials are discussed, along with approaches to enhance valence-band dispersion to reduce effective mass and increase mobility. Strategies to reduce interfacial defects, off-state current, and material instability are suggested. Furthermore, it is shown that promising progress has been made in the performance of various types of devices based on p-type oxides. Several innovative approaches exist to fabricate transparent complementary metal oxide semiconductor (CMOS) devices, including novel device fabrication schemes and utilization of surface chemistry effects, resulting in good inverter gains. However, despite recent developments, p-type oxides still lag in performance behind their n-type counterparts, which have entered volume production in the display market. Recent successes along with the hurdles that stand in the way of commercial success of p-type oxide semiconductors are presented.

  19. Recent Developments in p-Type Oxide Semiconductor Materials and Devices.

    Science.gov (United States)

    Wang, Zhenwei; Nayak, Pradipta K; Caraveo-Frescas, Jesus A; Alshareef, Husam N

    2016-05-01

    The development of transparent p-type oxide semiconductors with good performance may be a true enabler for a variety of applications where transparency, power efficiency, and greater circuit complexity are needed. Such applications include transparent electronics, displays, sensors, photovoltaics, memristors, and electrochromics. Hence, here, recent developments in materials and devices based on p-type oxide semiconductors are reviewed, including ternary Cu-bearing oxides, binary copper oxides, tin monoxide, spinel oxides, and nickel oxides. The crystal and electronic structures of these materials are discussed, along with approaches to enhance valence-band dispersion to reduce effective mass and increase mobility. Strategies to reduce interfacial defects, off-state current, and material instability are suggested. Furthermore, it is shown that promising progress has been made in the performance of various types of devices based on p-type oxides. Several innovative approaches exist to fabricate transparent complementary metal oxide semiconductor (CMOS) devices, including novel device fabrication schemes and utilization of surface chemistry effects, resulting in good inverter gains. However, despite recent developments, p-type oxides still lag in performance behind their n-type counterparts, which have entered volume production in the display market. Recent successes along with the hurdles that stand in the way of commercial success of p-type oxide semiconductors are presented.

  20. Morphological and photoelectrochemical characterization of core-shell nanoparticle films for dye-sensitized solar cells: Zn-O type shell on SnO2 and TiO2 cores.

    Science.gov (United States)

    Park, N G; Kang, M G; Kim, K M; Ryu, K S; Chang, S H; Kim, D K; van de Lagemaat, J; Benkstein, K D; Frank, A J

    2004-05-11

    Core-shell type nanoparticles with SnO2 and TiO2 cores and zinc oxide shells were prepared and characterized by surface sensitive techniques. The influence of the structure of the ZnO shell and the morphology ofnanoparticle films on the performance was evaluated. X-ray absorption near-edge structure and extended X-ray absorption fine structure studies show the presence of thin ZnO-like shells around the nanoparticles at low Zn levels. In the case of SnO2 cores, ZnO nanocrystals are formed at high Zn/Sn ratios (ca. 0.5). Scanning electron microscopy studies show that Zn modification of SnO2 nanoparticles changes the film morphology from a compact mesoporous structure to a less dense macroporous structure. In contrast, Zn modification of TiO2 nanoparticles has no apparent influence on film morphology. For SnO2 cores, adding ZnO improves the solar cell efficiency by increasing light scattering and dye uptake and decreasing recombination. In contrast, adding a ZnO shell to the TiO2 core decreases the cell efficiency, largely owing to a loss of photocurrent resulting from slow electron transport associated with the buildup of the ZnO surface layer.

  1. Effect of welding process, type of electrode and electrode core diameter on the tensile property of 304L austenitic stainless steel

    Directory of Open Access Journals (Sweden)

    Akinlabi OYETUNJI

    2014-11-01

    Full Text Available The effect of welding process, type of electrode and electrode core diameter on the tensile property of AISI 304L Austenitic Stainless Steel (ASS was studied. The tensile strength property of ASS welded samples was evaluated. Prepared samples of the ASS were welded under these three various variables. Tensile test was then carried out on the welded samples. It was found that the reduction in ultimate tensile strength (UTS of the butt joint samples increases with increase in core diameter of the electrode. Also, the best electrode for welding 304L ASS is 308L stainless steel-core electrode of 3.2 mm core diameter. It is recommended that the findings of this work can be applied in the chemical, food and oil industries where 304L ASS are predominantly used.

  2. X-ray inspection of composite materials for aircraft structures using detectors of Medipix type

    Science.gov (United States)

    Jandejsek, I.; Jakubek, J.; Jakubek, M.; Prucha, P.; Krejci, F.; Soukup, P.; Turecek, D.; Vavrik, D.; Zemlicka, J.

    2014-05-01

    This work presents an overview of promising X-ray imaging techniques employed for non-destructive defectoscopy inspections of composite materials intended for the Aircraft industry. The major emphasis is placed on non-tomographic imaging techniques which do not require demanding spatial and time measurement conditions. Imaging methods for defects visualisation, delamination detection and porosity measurement of various composite materials such as carbon fibre reinforced polymers and honeycomb sendwiches are proposed. We make use of the new large area WidePix X-ray imaging camera assembled from up to 100 edgeless Medipix type detectors which is highly suitable for this type of measurements.

  3. Type-II CdS/ZnSe core/shell heterostructures: UV–vis absorption, photoluminescence and Raman scattering studies

    Energy Technology Data Exchange (ETDEWEB)

    Ca, Nguyen Xuan [Faculty of Physics and Technology, Thai Nguyen University of Science, Thai Nguyen (Viet Nam); Lien, V.T.K. [Faculty of Physics, Thai Nguyen University of Education, Thai Nguyen (Viet Nam); Nghia, N.X., E-mail: nghianx.ims@gmail.com [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi (Viet Nam); Duy Tan University, 182 Nguyen Van Linh, Da Nang (Viet Nam); Chi, T.T.K. [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi (Viet Nam); Phan, T.L. [Department of Physics and Oxide Research Center, Hankuk University of Foreign Studies, Yongin 449-791 (Korea, Republic of)

    2015-10-15

    Graphical abstract: - Highlights: • Type-II CdS/ZnSe core/shell heterostructures. • Typical signatures to identify correct type-II CdS/ZnSe core/shell heterostructures. • UV–vis absorption, photoluminescence and Raman scattering studies. - Abstract: This work presents the fabrication of type-II CdS/ZnSe core/shell heterostructures based on the wet chemical method in octadecene (ODE) solvent. The fabrication processes were monitored by spectrometric techniques of UV–vis absorption, photoluminescence (PL) and Raman scattering (RS). We point out that CdS cores are necessary to be grown at high temperatures of 290–310 °C to improve their crystal quality. Meanwhile, the ZnSe-shell growth is needed to be carried out at low-enough temperatures, and the injection speed of the precursors CdS cores, and Zn{sup 2+} and Se{sup 2−} ions into the reaction solvent is as swift as possible. These conditions are necessary to restrict the dissolution of CdS cores during the ZnSe shell growth, and the formation of the other structure types, such as CdS/CdSe or CdS/(Cd,Zn)–(S,Se)/ZnSe. We also suggest typical signatures to identify the successful fabrication of type-II CdS/ZnSe core/shell heterostructures, which are based on the tail features of UV–vis absorption spectra, the linear dependence of the PL-peak energy on a cubic root of the excitation power, and long lifetimes of emission peaks. Besides these signatures, the study of phonon-vibration spectra is also necessary. Having studied the dependences of emission energy on excitation energy, we found an optimal thickness of the ZnSe shell coated on CdS cores. Apart from this thickness, the spatial separation of the carriers between the CdS core and the ZnSe shell will be significantly declined.

  4. The effect of material and flushing water type on urine scale formation.

    Science.gov (United States)

    Hashemi, Shervin; Han, Mooyoung; Kim, Tschungil

    2015-01-01

    One of the important challenges with current sanitation practices is pipe blockage in urinals caused by urine scale formation. Urinal material and flushing water type are the two most important factors affecting scale formation. This paper examines the scale formation process on different materials which are commonly used in urinal manufacturing and exposed to different urine-based aqua cultures. This study shows that urine scale formation is the greatest for carbon steel material, and the least for PVC. Additionally, material exposure to the urine-rainwater mixture resulted in the smallest amount of scale formation. Based on these results, two new methods for improving sanitation practices are proposed: (1) using PVC as production material for urinals and pipelines; and (2) using rainwater for flushing systems.

  5. Theoretical and Experimental Evaluation of the Temperature Distribution in a Dry Type Air Core Smoothing Reactor of HVDC Station

    Directory of Open Access Journals (Sweden)

    Yu Wang

    2017-05-01

    Full Text Available The outdoor ultra-high voltage (UHV dry-type air-core smoothing reactors (DASR of High Voltage Direct Current systems are equipped with a rain cover and an acoustic enclosure. To study the convective heat transfer between the DASR and the surrounding air, this paper presents a coupled model of the temperature and fluid field based on the structural features and cooling manner. The resistive losses of encapsulations calculated by finite element method (FEM were used as heat sources in the thermal analysis. The steady fluid and thermal field of the 3-D reactor model were solved by the finite volume method (FVM, and the temperature distribution characteristics of the reactor were obtained. Subsequently, the axial and radial temperature distributions of encapsulation were investigated separately. Finally, an optical fiber temperature measurement scheme was used for an UHV DASR under natural convection conditions. Comparative analysis showed that the simulation results are in good agreement with the experimental data, which verifies the rationality and accuracy of the numerical calculation. These results can serve as a reference for the optimal design and maintenance of UHV DASRs.

  6. Influence of particle size and shell thickness of core-shell packing materials on optimum experimental conditions in preparative chromatography.

    Science.gov (United States)

    Horváth, Krisztián; Felinger, Attila

    2015-08-14

    The applicability of core-shell phases in preparative separations was studied by a modeling approach. The preparative separations were optimized for two compounds having bi-Langmuir isotherms. The differential mass balance equation of chromatography was solved by the Rouchon algorithm. The results show that as the size of the core increases, larger particles can be used in separations, resulting in higher applicable flow rates, shorter cycle times. Due to the decreasing volume of porous layer, the loadability of the column dropped significantly. As a result, the productivity and economy of the separation decreases. It is shown that if it is possible to optimize the size of stationary phase particles for the given separation task, the use of core-shell phases are not beneficial. The use of core-shell phases proved to be advantageous when the goal is to build preparative column for general purposes (e.g. for purification of different products) in small scale separations.

  7. Core Binding Factor β Protects HIV, Type 1 Accessory Protein Viral Infectivity Factor from MDM2-mediated Degradation.

    Science.gov (United States)

    Matsui, Yusuke; Shindo, Keisuke; Nagata, Kayoko; Yoshinaga, Noriyoshi; Shirakawa, Kotaro; Kobayashi, Masayuki; Takaori-Kondo, Akifumi

    2016-11-25

    HIV, type 1 overcomes host restriction factor apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3 (APOBEC3) proteins by organizing an E3 ubiquitin ligase complex together with viral infectivity factor (Vif) and a host transcription cofactor core binding factor β (CBFβ). CBFβ is essential for Vif to counteract APOBEC3 by enabling the recruitment of cullin 5 to the complex and increasing the steady-state level of Vif protein; however, the mechanisms by which CBFβ up-regulates Vif protein remains unclear. Because we have reported previously that mouse double minute 2 homolog (MDM2) is an E3 ligase for Vif, we hypothesized that CBFβ might protect Vif from MDM2-mediated degradation. Co-immunoprecipitation analyses showed that Vif mutants that do not bind to CBFβ preferentially interact with MDM2 and that overexpression of CBFβ disrupts the interaction between MDM2 and Vif. Knockdown of CBFβ reduced the steady-state level of Vif in MDM2-proficient cells but not in MDM2-null cells. Cycloheximide chase analyses revealed that Vif E88A/W89A, which does not interact with CBFβ, degraded faster than wild-type Vif in MDM2-proficient cells but not in MDM2-null cells, suggesting that Vif stabilization by CBFβ is mainly caused by impairing MDM2-mediated degradation. We identified Vif R93E as a Vif variant that does not bind to MDM2, and the virus with this substitution mutation was more resistant to APOBEC3G than the parental virus. Combinatory substitution of Vif residues required for CBFβ binding and MDM2 binding showed full recovery of Vif steady-state levels, supporting our hypothesis. Our data provide new insights into the mechanism of Vif augmentation by CBFβ.

  8. Analysis of resin-dentin interface morphology and bond strength evaluation of core materials for one stage post-endodontic restorations.

    Directory of Open Access Journals (Sweden)

    Kerstin Bitter

    Full Text Available PURPOSE: Restoration of endodontically treated teeth using fiber posts in a one-stage procedure gains more popularity and aims to create a secondary monoblock. Data of detailed analyses of so called "post-and-core-systems" with respect to morphological characteristics of the resin-dentin interface in combination with bond strength measurements of fiber posts luted with these materials are scarce. The present study aimed to analyze four different post-and-core-systems with two different adhesive approaches (self-etch and etch-and-rinse. MATERIALS AND METHODS: Human anterior teeth (n = 80 were endodontically treated and post space preparations and post placement were performed using the following systems: Rebilda Post/Rebilda DC/Futurabond DC (Voco (RB, Luxapost/Luxacore Z/Luxabond Prebond and Luxabond A+B (DMG (LC, X Post/Core X Flow/XP Bond and Self Cure Activator (Dentsply DeTrey (CX, FRC Postec/MultiCore Flow/AdheSE DC (Ivoclar Vivadent (MC. Adhesive systems and core materials of 10 specimens per group were labeled using fluorescent dyes and resin-dentin interfaces were analyzed using Confocal Laser Scanning Microscopy (CLSM. Bond strengths were evaluated using a push-out test. Data were analyzed using repeated measurement ANOVA and following post-hoc test. RESULTS: CLSM analyses revealed significant differences between groups with respect to the factors hybrid layer thickness (p<0.0005 and number of resin tags (p = 0.02; ANOVA. Bond strength was significantly affected by core material (p = 0.001, location inside the root canal (p<0.0005 and incorporation of fluorescent dyes (p = 0.036; ANOVA. CX [7.7 (4.4 MPa] demonstrated significantly lower bond strength compared to LC [14.2 (8.7 MPa] and RB [13.3 (3.7 MPa] (p<0.05; Tukey HSD but did not differ significantly from MC [11.5 (3.5 MPa]. CONCLUSION: It can be concluded that bond strengths inside the root canal were not affected by the adhesive approach of the post-and-core-system. All systems

  9. Effects of different acids and etching times on the bond strength of glass fiber-reinforced composite root canal posts to composite core material.

    Science.gov (United States)

    Güler, Ahmet Umut; Kurt, Murat; Duran, Ibrahim; Uludamar, Altay; Inan, Ozgur

    2012-01-01

    To investigate the effects of different acids and etching times on the bond strength of glass fiber-reinforced composite (FRC) posts to composite core material. Twenty-six FRC posts (FRC Postec Plus) were randomly divided into 13 groups (each n = 2). One group received no surface treatment (control). The posts in the other groups were acid etched with 35% phosphoric acid and 5% and 9.6% hydrofluoric acid gel for four different etching times (30, 60, 120, and 180 seconds). A cylindric polytetrafluoroethylene mold was placed around the treated posts and filled with dual-cure composite core material (MultiCore Flow). All samples were light cured for 60 seconds. After 24 hours of water storage, the specimens were sectioned perpendicularly to the bonded interface under water cooling to obtain 2-mm post-and-core specimens. Eight specimens were made from each group. Push-out tests were performed at a crosshead speed of 0.5 mm/min using a universal testing machine. Data were analyzed by one-way ANOVA followed by the Tukey honestly significant difference test (alpha = .05). The lowest bond strength was observed in the control group (12.51 megapascal [MPa]). No statistical significant difference was observed among group H5-120 (20.31 MPa), group H9-120 (20.55 MPa), or group P-180 (20.57 MPa) (P > .05). These groups demonstrated the highest bond strength values (P strength when compared with the control group. Acid-etching with 5% hydrofluoric acid and 9.6% hydrofluoric acid for 2 minutes and with 35% phosphoric acid for 3 minutes (groups H5-120, H9-120, and P-180, respectively) demonstrated the highest bond strength values between the FRC post and composite core material. Although the bond strength was increased by prolonged acid etching, the microstructure of the FRC posts might have been damaged.

  10. Development and experimental validation of a calculation scheme for nuclear heating evaluation in the core of the OSIRIS material testing reactor

    Energy Technology Data Exchange (ETDEWEB)

    Malouch, F. [Saclay Center CEA, DEN/DANS/DM2S/SERMA, F-91191 Gif-sur-Yvette Cedex (France)

    2011-07-01

    The control of the temperature in material samples irradiated in a material testing reactor requires the knowledge of the nuclear heating caused by the energy deposition by neutrons and photons interacting in the irradiation device structures. Thus, a neutron-photonic three-dimensional calculation scheme has been developed to evaluate the nuclear heating in experimental devices irradiated in the core of the OSIRIS MTR reactor (CEA/Saclay Center). The aim is to obtain a predictive tool for the nuclear heating estimation in irradiation devices. This calculation scheme is mainly based on the TRIPOLI-4 three-dimensional continuous-energy Monte Carlo transport code, developed by CEA (Saclay Center). An experimental validation has been carried out on the basis of nuclear heating measurements performed in the OSIRIS core. After an overview of the experimental devices irradiated in the OSIRIS reactor, we present the calculation scheme and the first results of the experimental validation. (authors)

  11. Preparation of New Type Ni-P Micro/Nano Metal Material Based on Bacteria Shape

    Institute of Scientific and Technical Information of China (English)

    Xin Liang; Jianhua Liu; Songmei Li

    2009-01-01

    A new type of Ni-P alloy with rod-shape was prepared by electroless deposition method based on the shape of Nocadia, a kind of bacteria. The material was characterized by microbiological method, scanning elec-tron microscope, energy dispersion spectroscopy, transmission electron microscopy, fourier transform infrared spectroscopy, X-ray diffraction and vibrant sample magnetometer. It was found that Ni-P alloy deposited on Nocadia surface was amorphous when pH=8.0. The amount of Ni crystalline increased with pH of plating solution. Ni-P nano-particles deposited on active locations on the surface at the initial stage, and then ho-mogeneous Ni-P film formed with time. Nocadia remained their original rod shape after Ni-P nano-particles deposition. The new type metal material formed of Ni-P alloy with nano-particles was prepared. The mag-netization of the material prepared at pH=9.7 is greater than that prepared at pH=8.0. The magnetic loss of the material prepared at pH=9.7 is less than 0.1. The dielectric loss exceeds 0.3 when frequency is higher than 14 GHz, which is 1.5 at 18 GHz. The new type Ni-P metal material with Nocadia shape has dielectric loss property.

  12. Zero phase sequence impedance and tank heating model for three phase three leg core type power transformers coupling magnetic field and electric circuit equations in finite element software

    Energy Technology Data Exchange (ETDEWEB)

    Ngnegueu, T.; Mailhot, M.; Munar, A. [Jeumont Schneider Transformateurs, Lyon (France); Sacotte, M. [France-Transfo. Voie romaine, Mezieres-Les-Metz (France)

    1995-05-01

    In this paper, the authors present a finite element model for the calculation of zero phase sequence reactance for three phase three leg core type power transformers. An axisymmetrical approximation is assumed. A simplified model is used to assess the tank`s hottest spot temperature.

  13. Dynamic Use of Digital Library Material - Supporting Users with Typed Links in Open Hypermedia

    DEFF Research Database (Denmark)

    Grønbæk, Kaj; Hansen, Klaus Marius; Yndigegn, Christian

    1999-01-01

    This paper introduces a novel approach to supporting digital library users in organising and annotating material. We have extended the concept of open hypermedia by introducing typed links, which support: addition of (user-defined) semantics to hypertexts, user navigation, and machine supported...

  14. Titanium nitride: A new Ohmic contact material for n-type CdS

    NARCIS (Netherlands)

    Didden, A.; Battjes, H.; Machunze, R.; Dam, B.; Van de Krol, R.

    2011-01-01

    In devices based on CdS, indium is often used to make Ohmic contacts. Since indium is scarce and expensive, suitable replacement materials need to be found. In this work, we show that sputtered titanium nitride forms an Ohmic contact with n-type CdS. The CdS films, deposited with chemical bath depos

  15. Study of the interocclusal distortion in impressions taken with different types of closed-mouth trays and two types of impression materials

    OpenAIRE

    Mañes-Ferrer, José Félix; Selva-Otaolaurruchi, Eduardo José; Parra-Arenos, Carmina; Selfa-Bas, Isabel

    2010-01-01

    The aim of this study was to compare different types of impression trays for the closed-mouth impression technique, using two different types of impression material. For this study, five different types of impression trays were used with two different types of impression materials, one of addition silicone and the other of polyether. We designed a model used for taking the impressions and for measuring interocclusal distortion. The results obtained show that the impression trays COE (GC (R) G...

  16. Effect of cyclic loading on fracture strength and microleakage of a quartz fiber dowel with different adhesive, cement and resin core material combinations.

    Science.gov (United States)

    Baldissara, P; Ozcan, M; Melilli, D; Valandro, L F

    2010-01-01

    This study evaluated the performance of different adhesive-cement-core combinations coupled with quartz fiber dowels after cyclic loading and fracture strength tests and assessed the microleakage using dye penetration method. Forty maxillary canines (N=10 per group) were restored with fiber dowels (Quartz fiber DT Light Post) and four adhesive-cement-core material combinations (Group 1: All-Bond 2+C&B [root]/All-Bond 2+Biscore [core]; Group 2: All-Bond 2+Bisfil 2B [root]/All-Bond 2+Bisfil 2B [core]; Group 3: Scotchbond 1+RelyX ARC [root]/Scotchbond 1+Supreme [core]; Group 4: RelyX Unicem [root]/Scotchbond 1+Filtek Supreme [core]). The specimens were initially cyclic loaded (x2,000,000, 8 Hz, 3 to 100 N at 45 °C under 37±3 °C water irrigation) and then immersed in 0.5% basic fuchsine at 37 °C for 24 hours for dye penetration and interface failure detection. The failure surfaces were observed under the stereomicroscope (x100 magnification). Circumferential and centripetal dye penetration was scored at the buccal and lingual sites. Only three specimens failed macroscopically during cyclic loading. No significant difference was found among the groups for the number of resisted cycles (P=0.9). Mean fracture strength between the groups were also not statistically significant (213±63-245±71 N) (P=0.740) (ANOVA). All four groups showed high values of dye penetration along the restoration interfaces being not significant from each other (P=0.224) (Kruskal-Wallis). The lingual sides of the teeth where the load applied, showed significantly higher incidence of detachment between the core and the dentin (100%, 90%, 100%, 90% for groups 1, 2, 3, 4, respectively) compared to the buccal side (30%, 30%, 60%, 40%) (P=0.032, c2 test). In 13 specimens (32.5%) crack lines at the coronal area were observed. Fracture strength was not significantly correlated with dye penetration (P=0.1803, r=-0.2162, Linear Regression and Correlation test). Different combinations of adhesive

  17. Application of neutron transmutation doping method to initially p-type silicon material.

    Science.gov (United States)

    Kim, Myong-Seop; Kang, Ki-Doo; Park, Sang-Jun

    2009-01-01

    The neutron transmutation doping (NTD) method was applied to the initially p-type silicon in order to extend the NTD applications at HANARO. The relationship between the irradiation neutron fluence and the final resistivity of the initially p-type silicon material was investigated. The proportional constant between the neutron fluence and the resistivity was determined to be 2.3473x10(19)nOmegacm(-1). The deviation of the final resistivity from the target for almost all the irradiation results of the initially p-type silicon ingots was at a range from -5% to 2%. In addition, the burn-up effect of the boron impurities, the residual (32)P activity and the effect of the compensation characteristics for the initially p-type silicon were studied. Conclusively, the practical methodology to perform the neutron transmutation doping of the initially p-type silicon ingot was established.

  18. A Novel n-Type Organosilane-Metal Ion Hybrid of Rhodamine B and Copper Cation for Low-Temperature Thermoelectric Materials.

    Science.gov (United States)

    Bertram, John R; Penn, Aubrey; Nee, Matthew J; Rathnayake, Hemali

    2017-03-29

    An n-type organosilane-metal ion hybrid of Rhodamine B-silane and copper cation (Cu-RBS) was investigated as a low-temperature thermoelectric material. Computational analysis revealed the most likely localized binding site of Cu(2+) was to the Rhodamine B core and provided predictions of molecular orbitals and electrostatic potentials upon complexation. The concentration-dependent optical absorption and emission spectra confirmed the effective metal-ligand charge transfer from Cu(2+) to the xanthene core of RBS, indicating the potential for improved electrical properties for the complex relative to RBS. The electrical conductivity and Seebeck thermoelectric (TE) behavior were evaluated and compared with its precursor complex of Rhodamine B and copper cation. While a moderately high electrical conductivity of 4.38 S m(-1) was obtained for the Cu-RBS complex, the relatively low Seebeck coefficient of -26.2 μV/K resulted in a low TE power factor. However, compared to other organic doped materials, these results were promising toward developing n-type thermoelectric materials with no doping agents. Both phase segregation and thin film heterogeneity remain to be optimized; thus, the balance between Cu(2+) domains and RBS domain phases will likely yield higher Seebeck coefficients and improved power factors.

  19. Influence of core design, production technique, and material selection on fracture behavior of yttria-stabilized tetragonal zirconia polycrystal fixed dental prostheses produced using different multilayer techniques: split-file, over-pressing, and manually built-up veneers

    Directory of Open Access Journals (Sweden)

    Mahmood DJH

    2016-02-01

    Full Text Available Deyar Jallal Hadi Mahmood, Ewa H Linderoth, Ann Wennerberg, Per Vult Von Steyern Department of Prosthetic Dentistry, Faculty of Odontology, Malmö University, Malmö, Sweden Aim: To investigate and compare the fracture strength and fracture mode in eleven groups of currently, the most commonly used multilayer three-unit all-ceramic yttria-stabilized tetragonal zirconia polycrystal (Y-TZP fixed dental prostheses (FDPs with respect to the choice of core material, veneering material area, manufacturing technique, design of connectors, and radii of curvature of FDP cores. Materials and methods: A total of 110 three-unit Y-TZP FDP cores with one intermediate pontic were made. The FDP cores in groups 1–7 were made with a split-file design, veneered with manually built-up porcelain, computer-aided design-on veneers, and over-pressed veneers. Groups 8–11 consisted of FDPs with a state-of-the-art design, veneered with manually built-up porcelain. All the FDP cores were subjected to simulated aging and finally loaded to fracture. Results: There was a significant difference (P<0.05 between the core designs, but not between the different types of Y-TZP materials. The split-file designs with VITABLOCS® (1,806±165 N and e.max® ZirPress (1,854±115 N and the state-of-the-art design with VITA VM® 9 (1,849±150 N demonstrated the highest mean fracture values. Conclusion: The shape of a split-file designed all-ceramic reconstruction calls for a different dimension protocol, compared to traditionally shaped ones, as the split-file design leads to sharp approximal indentations acting as fractural impressions, thus decreasing the overall strength. The design of a framework is a crucial factor for the load bearing capacity of an all-ceramic FDP. The state-of-the-art design is preferable since the split-file designed cores call for a cross-sectional connector area at least 42% larger, to have the same load bearing capacity as the state-of-the-art designed

  20. Biaxial flexural strength and phase transformation of Ce-TZP/Al2O3 and Y-TZP core materials after thermocycling and mechanical loading.

    Science.gov (United States)

    Bankoğlu Güngör, Merve; Yılmaz, Handan; Aydın, Cemal; Karakoca Nemli, Seçil; Turhan Bal, Bilge; Tıraş, Tülay

    2014-06-01

    The purpose of the present study was to evaluate the effect of thermocycling and mechanical loading on the biaxial flexural strength and the phase transformation of one Ce-TZP/Al2O3 and two Y-TZP core materials. Thirty disc-shaped specimens were obtained from each material. The specimens were randomly divided into three groups (control, thermocycled, and mechanically loaded). Thermocycling was subjected in distilled water for 10000 cycles. Mechanical loading was subjected with 200 N loads at a frequency of 2 Hz for 100000 times. The mean biaxial flexural strength and phase transformation of the specimens were tested. The Weibull modulus, characteristic strength, 10%, 5% and 1% probabilities of failure were calculated using the biaxial flexural strength data. The characteristic strengths of Ce-TZP/Al2O3 specimens were significantly higher in all groups compared with the other tested materials (Pstrength of the tested materials.

  1. 49 CFR 173.467 - Tests for demonstrating the ability of Type B and fissile materials packagings to withstand...

    Science.gov (United States)

    2010-10-01

    ... Type B and fissile materials packagings to withstand accident conditions in transportation. Each Type B packaging or packaging for fissile material must meet the test requirements prescribed in 10 CFR part 71 for... 49 Transportation 2 2010-10-01 2010-10-01 false Tests for demonstrating the ability of Type B...

  2. An investigation into the role of core porcelain thickness and lamination in determining the flexural strength of In-Ceram dental materials.

    Science.gov (United States)

    Alshehri, Sharifa Abdullah

    2011-06-01

    A biaxial flexure test was conducted to evaluate the effect of reducing the thickness of In-Ceram core material and veneering with Vitadur α dentine porcelain on its flexural strength. Four groups of 10 discs were tested; group I discs were In-Ceram discs with mean thickness of 1.58 ± 0.08 mm, group II discs were In-Ceram discs with mean thickness of 1.0 ± 0.11 mm, group III discs were laminated In-Ceram core porcelain/Vitadur α discs with a mean total thickness of 2.06 ± 0.15 mm and core porcelain thickness of 1.0 ± 0.11 mm; group IV discs were Vitadur α discs with a mean thickness of 2.08 ± 0.16 mm. Mean flexural strength values decreased between groups: 436 ± 38 MPa for group I, 352 ± 30 MPa for group II, 237 ± 24 MPa for group III, and 77 ± 14 MPa for group IV. The result of ANOVA and Tukey tests indicated that the mean flexural strength of group II was significantly less than group I, indicating that thickness of the In-Ceram core provides critical flexural strength to the final product. The addition of ≈ 1 mm of Vitadur α veneering porcelain to In-Ceram core significantly (p= 0.05) reduced the flexural strength as compared to the nonveneered In-Ceram core specimens (group II). The Vitadur α specimens (group IV) were significantly weaker than all the other groups. This study indicates that lamination should be avoided in areas where maximum strength is required for In-Ceram all-ceramic crowns and bridges. © 2011 by the American College of Prosthodontists.

  3. Reactor Materials Program: Mechanical properties of irradiated Types 304 and 304L stainless steel weldment components

    Energy Technology Data Exchange (ETDEWEB)

    Sindelar, R.L.; Caskey, G.R. Jr.

    1991-12-01

    The vessels (reactor tanks) of the Savannah River Site nuclear production reactors constructed in the 1950`s are comprised of Type 304 stainless steel with Type 308 stainless steel weld filler. Irradiation exposure to the reactor tank sidewalls through reactor operation has caused a change in the mechanical properties of these materials. A database of as-irradiated mechanical properties for site-specific materials and irradiation conditions has been produced for reactor tank structural analyses and to quantify the effects of radiation-induced materials degradation for evaluating reactor service life. The data has been collected from the SRL Reactor Materials Program (RMP) irradiations and testing of archival stainless steel weldment components and from previous SRL programs to measure properties of irradiated reactor Thermal Shield weldments and reactor tank (R-tank) sidewall material. Irradiation programs of the RMP are designed to quantify mechanical properties at tank operating temperatures following irradiation to present and future tank wall maximum exposure conditions. The exposure conditions are characterized in terms of fast neutron fluence (E{sub n} > 0.1 MeV) and displacements per atom (dpa){sup 3}. Tensile properties, Charpy-V notch toughness, and elastic-plastic fracture toughness were measured for base, weld, and weld heat-affected zone (HAZ) weldment components from archival piping specimens following a Screening Irradiation in the University of Buffalo Reactor (UBR) and following a Full-Term Irradiation in the High Flux Isotope Reactor (HFIR).

  4. Reactor Materials Program: Mechanical properties of irradiated Types 304 and 304L stainless steel weldment components

    Energy Technology Data Exchange (ETDEWEB)

    Sindelar, R.L.; Caskey, G.R. Jr.

    1991-12-01

    The vessels (reactor tanks) of the Savannah River Site nuclear production reactors constructed in the 1950's are comprised of Type 304 stainless steel with Type 308 stainless steel weld filler. Irradiation exposure to the reactor tank sidewalls through reactor operation has caused a change in the mechanical properties of these materials. A database of as-irradiated mechanical properties for site-specific materials and irradiation conditions has been produced for reactor tank structural analyses and to quantify the effects of radiation-induced materials degradation for evaluating reactor service life. The data has been collected from the SRL Reactor Materials Program (RMP) irradiations and testing of archival stainless steel weldment components and from previous SRL programs to measure properties of irradiated reactor Thermal Shield weldments and reactor tank (R-tank) sidewall material. Irradiation programs of the RMP are designed to quantify mechanical properties at tank operating temperatures following irradiation to present and future tank wall maximum exposure conditions. The exposure conditions are characterized in terms of fast neutron fluence (E{sub n} > 0.1 MeV) and displacements per atom (dpa){sup 3}. Tensile properties, Charpy-V notch toughness, and elastic-plastic fracture toughness were measured for base, weld, and weld heat-affected zone (HAZ) weldment components from archival piping specimens following a Screening Irradiation in the University of Buffalo Reactor (UBR) and following a Full-Term Irradiation in the High Flux Isotope Reactor (HFIR).

  5. Hydrothermal Synthesis of Xonotlite-type Calcium Silicate Insulation Material Using Industrial Zirconium Waste Residue

    Institute of Scientific and Technical Information of China (English)

    JIANG Jinguo; CUI Chong; LIU Jinqiang; LIAO Wenli

    2011-01-01

    Xonotlite-type insulation material was prepared by hydrothermal synthesis technology using industrial zirconium waste residue in this paper, and the phase analysis together with the observation of micro-morphology were also carried out by XRD, SEM and TEM. The density and thermal conductivity were measured finally. The results indicate, chlorine ion impurity contained in zirconium waste residue can be removed effectively via water washed process, and the reactive activity of silicon dioxide is almost not affected,which make it be a good substitution of silicon material for the preparation of calcium silicate insulation material by hydrothermal synthesis technique. The density and thermal conductivity of xonotlite-type calcium silicate insulation material obtained by hydrothermal synthesis technique can reach 159 kg/m3, 0.049 W/(m·°C), respectively, meeting with National Standard well, when synthesis conditions are selected as follows: Ca/Si molar ratio equal to 1, synthesis temperature at 210 ℃ and kept for 8 hrs. It provides a new approach to realize lightweight and low thermal conductivity of calcium silicate insulation material.

  6. Combined 238U/235U and Pb Isotopics of Planetary Core Material: The Absolute Age of the IVA Iron Muonionalusta

    Science.gov (United States)

    Brennecka, G. A.; Amelin, Y.; Kleine, T.

    2016-08-01

    We report a measured 238U/235U for the IVA iron Muonionalusta. This measured value requires an age correction of ~7 Myr to the previously published Pb-Pb age. This has major implications for our understanding of planetary core formation and cooling.

  7. Pseudomembranous colitis on aytopsy materials of large multi-type hospital

    OpenAIRE

    2014-01-01

    As a result of wide and irrational antibiotics using the problem of AAC has become an issue. According to medical sources Clostridium difficile-associated diarrhea (pseudomembranous colitis) is not registered and its clinical diagnostics is unsatisfactory.The purpose of the research is to study the pseudomembranouscolitis incidence on autopsy material in a multi-type hospital and to give its clinical and morphological characteristics.Methods and materials: the medical records (autopsy protoco...

  8. The thermal behaviors and phase diagrams of the Ising-type endohedral fullerene with magnetic core and diluted magnetic shell (Core@Shell20)

    Science.gov (United States)

    Kantar, Ersin

    2017-08-01

    We have carried out theoretical studies on Ising-type endohedral fullerene (EF) structure with a dopant magnetic atom encaged within the diluted magnetic spherical cage to examine the evolution in magnetic behaviors. We show how the thermal behaviors and phase diagrams of Ising-type EF are affected by diluted surface, crystal field and exchange couplings. We have used to investigate theoretically the effect of Hamiltonian parameters the effective field calculations within Ising model framework. The model Hamiltonian includes nearest neighbor ferromagnetic and antiferromagnetic center-surface (C-S) interaction as well as ferromagnetic surface interaction. We have shown that the system exhibits the first and second order phase transitions as well as tricritical point. In particular, the conditions for the occurrence of these reentrant and double reentrant behaviors are given explicitly.

  9. Influence of Stress History on Elastic and Frictional Properties of Core Material from IODP Expeditions 315 and 316, NanTroSEIZE Transect: Implications for the Nankai Trough Accretionary Prism

    Science.gov (United States)

    Knuth, M. W.; Tobin, H. J.; Marone, C.; Saffer, D. M.; Hashimoto, Y.

    2009-12-01

    We present results of ultrasonic P and S-wave velocity measurements on core material recovered during NanTroSEIZE Stage 1 Expeditions 315 and 316 to the Nankai Trough Accretionary Margin, focusing on how different stress paths during subduction and exhumation along regional thrust faults influence the elastic moduli and anisotropy of various components of the accretionary prism. The influence of changes in pore pressure and confining pressure on the elastic properties of prism material has important implications for its mechanical strength, and understanding how elastic properties change along various stress paths will help us use 3D seismic tomography to draw inferences about overpressurization and fluid flow within the accretionary prism. We compare the velocities measured during shipboard physical properties characterization and logging-while-drilling data from Expedition 314 with 3D seismic velocity data and the results of previous shore-based studies to establish in situ conditions for material at various locations within the prism. We test both intact core material and disaggregated gouge and unlithified sediments from the upper prism, subjecting both samples types to a progression of confining pressure, pore pressure, and axial loading conditions representing normal consolidation and overconsolidation stress paths due to compaction and dewatering during burial and subsequent uplift by thrust faulting. While making continuous ultrasonic velocity measurements to determine changes in dynamic and quasistatic elastic moduli during axial and isotropic loading, we also subject granular material to frictional shear in a biaxial double-direct shearing configuration to measure how its frictional properties vary as a function of stress history.

  10. DEVELOPMENT OF A NEW TYPE A(F)RADIOACTIVE MATERIAL PACKAGING FOR THE DEPARTMENT OF ENERGY

    Energy Technology Data Exchange (ETDEWEB)

    Blanton, P.; Eberl, K.

    2008-09-14

    In a coordinated effort, the Department of Transportation (DOT) and Nuclear Regulatory Commission (NRC) proposed the elimination of the Specification Packaging from 49 CFR 173.[1] In accordance with the Federal Register, issued on October 1, 2004, new fabrication of Specification Packages would no longer be authorized. In accordance with the NRC final rulemaking published January 26, 2004, Specification Packagings are mandated by law to be removed from service no later than October 1, 2008. This coordinated effort and resulting rulemaking initiated a planned phase out of Specification Type B and Type A fissile (F) material transportation packages within the Department of Energy (DOE) and its subcontractors. One of the Specification Packages affected by this regulatory change is the UN1A2 Specification Package, per DOT 49 CFR 173.417(a)(6). To maintain continuing shipments of DOE materials currently transported in UN1A2 Specification Package after the existing authorization expires, a replacement Type A(F) material packaging design is under development by the Savannah River National Laboratory. This paper presents a summary of the prototype design effort and testing of the new Type A(F) Package development for the DOE. This paper discusses the progress made in the development of a Type A Fissile Packaging to replace the expiring 49 CFR UN1A2 Specification Fissile Package. The Specification Package was mostly a single-use waste disposal container. The design requirements and authorized radioactive material contents of the UN1A2 Specification Package were defined in 49 CFR. A UN1A2 Specification Package was authorized to ship up to 350 grams of U-235 in any enrichment and in any non-pyrophoric form. The design was specified as a 55-gallon 1A2 drum overpack with a body constructed from 18 gauge steel with a 16 gauge drum lid. Drum closure was specified as a standard 12-gauge ring closure. The inner product container size was not specified but was listed as any

  11. Material and Geometric Nonlinear Analysis of Functionally Graded Plate-Shell Type Structures

    Science.gov (United States)

    Moita, J. S.; Araújo, A. L.; Mota Soares, C. M.; Mota Soares, C. A.; Herskovits, J.

    2016-08-01

    A nonlinear formulation for general Functionally Graded Material plate-shell type structures is presented. The formulation accounts for geometric and material nonlinear behaviour of these structures. Using the Newton-Raphson incremental-iterative method, the incremental equilibrium path is obtained, and in case of snap-through occurrence the automatic arc-length method is used. This simple and fast element model is a non-conforming triangular flat plate/shell element with 24 degrees of freedom for the generalized displacements. It is benchmarked in the solution of some illustrative plate- shell examples and the results are presented and discussed with numerical alternative models. Benchmark tests with material and geometrically nonlinear behaviour are also proposed.

  12. Ab-initio study of the physics and chemistry of metals in planetary core materials and nanomaterials at relevant thermodynamics conditions

    Science.gov (United States)

    Alnemrat, Sufian

    Material science investigates the relationship between the structure of materials at the atomic or molecular scales and their macroscopic properties. Ab-initio DFT, atomistic force-field, and molecular dynamic simulations have been used to investigate the electronic, optical, structural, magnetic properties of group II-VI semiconductor nanoparticles, metal organic frameworks, amide-water complexes, and planetary core materials at the atomic and/or molecular level. Structure, density of electronic states, magnetic dipole moments, and HOMO-LUMO gaps of surface-passivated ZnnSem, Cd nTem, CdTe-core/ZnTe-shell, and ZnSe-core/CdSe-shell nanocrystals are calculated using a first principles. The intrinsic magnetic dipole moments are found to be strongly size dependent. The detailed analysis of the dipole moment as a function of particle size shows the appearance of zincblende-wurtzite polymorphism in these nano-particles. Energy-efficient adsorption processes are considered promising alternatives to traditional separation techniques. Mg-MOF-74, a magnesium-based metal organic framework, has been used as an efficient adsorbent structure for several gas separation purposes. Adsorption equilibria and kinetics of ethane, ethylene, propane, and propylene on Mg-MOF-74 were determined at temperatures of 278, 298, and 318 K and pressures up to 100 kPa. A grand canonical Monte Carlo simulation was conducted to calculate the adsorption isotherms and to explore adsorption mechanisms. I found that propylene and propane have a stronger affinity to the Mg-MOF-74 adsorbent than ethane and ethylene because of their significant dipole moments. Ab-initio molecular dynamics simulations were carried out to study the role of equilibrium volume and magnetism in Fe and FeX alloys (X=Ni, O) and their stability at earth core conditions. This study provides new insights into the pressure dependence of magnetism by tracking the hybridization between crystal orbitals for pressures up to 600 GPa in

  13. Synthesis and characterization of SiO2/Gd2O3:Eu core-shell luminescent materials.

    Science.gov (United States)

    Liu, Guixia; Hong, Guangyan; Sun, Duoxian

    2004-10-01

    Europium-doped Gd2O3 with an average size of approximately 15 nm was coated on the surface of preformed silica nanospheres by the wet chemical method. SEM and TEM photographs showed that SiO2/Gd2O3:Eu core-shell submicrospheres are obtained. XRD patterns indicated that the Gd2O3:Eu shell is crystalline after heat treatment. FTIR and XPS spectra showed that the Gd2O3:Eu shell is linked to the silica surface by forming a Si-O-Gd bond. Photoluminescence studies showed that the luminescent properties are still retained after coating on an inert silica core; additionally, we noted that the emitting peaks are broadened, which results from size effects and interface effects of nanocrystal.

  14. An Innovative Passive Residual Heat Removal System of an Open-Pool Type Research Reactor with Pump Flywheel and Gravity Core Cooling Tank

    Directory of Open Access Journals (Sweden)

    Kwon-Yeong Lee

    2015-01-01

    Full Text Available In an open-pool type research reactor, the primary cooling system can be designed to have a downward flow inside the core during normal operation because of the plate type fuel geometry. There is a flow inversion inside the core from the downward flow by the inertia force of the primary coolant to the upward flow by the natural circulation when the pump is turned off. To delay the flow inversion time, an innovative passive system with pump flywheel and GCCT is developed to remove the residual heat. Before the primary cooling pump starts up, the water level of the GCCT is the same as that of the reactor pool. During the primary cooling pump operation, the water in the GCCT is moved into the reactor pool because of the pump suction head. After the pump stops, the potential head generates a downward flow inside the core by moving the water from the reactor pool to the GCCT and removes the residual heat. When the water levels of the two pools are the same again, the core flow has an inversion of the flow direction, and natural circulation is developed through the flap valves.

  15. Investigation of a Coupled Arrhenius-Type/Rossard Equation of AH36 Material.

    Science.gov (United States)

    Qin, Qin; Tian, Ming-Liang; Zhang, Peng

    2017-04-13

    High-temperature tensile testing of AH36 material in a wide range of temperatures (1173-1573 K) and strain rates (10(-4)-10(-2) s(-1)) has been obtained by using a Gleeble system. These experimental stress-strain data have been adopted to develop the constitutive equation. The constitutive equation of AH36 material was suggested based on the modified Arrhenius-type equation and the modified Rossard equation respectively. The results indicate that the constitutive equation is strongly influenced by temperature and strain, especially strain. Moreover, there is a good agreement between the predicted data of the modified Arrhenius-type equation and the experimental results when the strain is greater than 0.02. There is also good agreement between the predicted data of the Rossard equation and the experimental results when the strain is less than 0.02. Therefore, a coupled equation where the modified Arrhenius-type equation and Rossard equation are combined has been proposed to describe the constitutive equation of AH36 material according to the different strain values in order to improve the accuracy. The correlation coefficient between the computed and experimental flow stress data was 0.998. The minimum value of the average absolute relative error shows the high accuracy of the coupled equation compared with the two modified equations.

  16. Degradation of sustainable mulch materials in two types of soil under laboratory conditions

    Science.gov (United States)

    Villena, Jaime; González, Sara; Moreno, Carmen; Aceituno, Patricia; Campos, Juan; Meco, Ramón; María Moreno, Marta

    2017-04-01

    Mulching is a technique used in cultivation worldwide, especially for vegetable crops, for reducing weed growth, minimising or eliminating soil erosion, and often for enhancing total yields. Manufactured plastic films, mainly polyethylene (PE), have been widely used for this purpose due to their excellent mechanical properties, light weight and relatively low prices in recent years. However, the use of PE is associated with serious environmental problems related to its petrochemical origin and its long shelf-life, which causes a waste problem in our crop fields. For this reason, the use of biodegradable mulch materials (biopolymers and papers) as alternative to PE is increasing nowadays, especially in organic farming. However, these materials can suffer an undesirable early degradation (and therefore not fulfilling their function successfully), greatly resulting from the type of soil. For this reason, this study aimed to analyse the degradation pattern of different mulch materials buried in two types of soils, clay and sand, under laboratory conditions (25°C, dark surroundings, constant humidity). The mulch materials used were: 1) black polyethylene (15 µm); black biopolymers (15 µm): 2) maize starch-based, 3) potato starch-based, 4) polylactic acid-based, 5) black paper, 85 g/m2. Periodically (every 15-20 days), the weight and surface loss of the different materials were recorded. The results indicate that mulch degradation was earlier and higher in the clay soil, especially in the paper and in the potato starch-based materials, followed by the maize starch-based mulch, while polylactic acid-based suffered the least and the latest degradation. Keywords: mulch, biodegradable, biopolymer, paper, degradation. Acknowledgements: the research was funded by Project RTA2011-00104-C04-03 from the INIA (Spanish Ministry of Economy and Competitiveness).

  17. Effect of different surface treatments on microtensile bond strength of two resin cements to aged simulated composite core materials.

    Science.gov (United States)

    Esmaeili, Behnaz; Alaghehmand, Homayoon; Shakerian, Mohadese

    2015-01-01

    Roughening of the aged composite resin core (CRC) surface seems essential for durable adhesion. The aim of this study was to investigate the influence of various surface treatments and different resin cements on microtensile bond strength (µ TBS) between two aged core build-up composites (CBCs) and feldspathic ceramic. A total of 16 composite blocks made of two CBCs, Core.it and Build-it were randomly assigned to four surface treatment groups after water storage and thermocycling (2 weeks and 500 cycles). Experimental groups included surface roughening with air abrasion (AA), hydrofluoric acid, pumice, and laser and then were bonded to computer-aided design/computer-aided manufacturing feldspathic ceramic blocks using two resin cements, Panavia F2 (PF), and Duo-link (DL). The µ TBS was tested, and the fracture mode was assessed. The data were analyzed with multiple analysis of variance to estimate the contribution of different surface treatments, resin cements, and two aged CRCs on µ TBS. Statistical significance level was set at α strength (P strength was in AA group cemented with PF (31.83 MPa). The most common failure mode was cohesive fracture in the cement. Different surface treatments had different effects on µ TBS of aged CRCs to feldspathic ceramics. PF was significantly better than DL.

  18. Evaluation of a new wide pore core-shell material (Aeris WIDEPORE) and comparison with other existing stationary phases for the analysis of intact proteins.

    Science.gov (United States)

    Fekete, Szabolcs; Berky, Róbert; Fekete, Jenő; Veuthey, Jean-Luc; Guillarme, Davy

    2012-05-04

    The separation of large biomolecules such as proteins or monoclonal antibodies (mAbs) by RPLC can be drastically enhanced thanks to the use of columns packed with wide-pore porous sub-2 μm particles or shell particles. In this context, a new wide-pore core-shell material has been recently released under the trademark Aeris WIDEPORE. It is made of a 3.2 μm solid inner core surrounded by a 0.2 μm porous layer (total particle size of 3.6 μm). The aim of this study was to evaluate the performance of this new material, compare it to other recently developed and older conventional wide-pore columns and demonstrate its applicability to real-life separations of proteins and mAbs. At first, the traditional h(min) values of the Aeris WIDEPORE column were determined for small model compounds. The h(min) values were equal to 1.7-1.8 and 1.4 for the 2.1 and 4.6 mm I.D. columns, respectively, which are in agreement with the values reported for other core-shell materials. In the case of a small protein Insulin (5.7 kDa), the achievable lowest h value was below 2 and this impressive result confirms that the Aeris WIDEPORE material should be dedicated to protein analysis. This column was then compared with five other commercially available wide-pore and medium-pore stationary phases, in the gradient elution mode, using various flow rates, gradient steepness and model proteins of MW=5.7-66.8 kDa. The Aeris WIDEPORE material often provided the best performance, in terms of peak capacity, peak capacity per time and pressure unit (PPT) and also based on the gradient kinetic plot representation. Finally, real separations of filgrastim (18.8 kDa) and its oxidized and reduced forms were performed on the different columns and the Aeris WIDEPORE material provided the most impressive performance (peak capacity>100 for t(grad)material was also evaluated on digested and reduced mAb and powerful, high-throughput separations were also attained.

  19. Acquisition process of typing skill using hierarchical materials in the Japanese language.

    Science.gov (United States)

    Ashitaka, Yuki; Shimada, Hiroyuki

    2014-08-01

    In the present study, using a new keyboard layout with only eight keys, we conducted typing training for unskilled typists. In this task, Japanese college students received training in typing words consisting of a pair of hiragana characters with four keystrokes, using the alphabetic input method, while keeping the association between the keys and typists' finger movements; the task was constructed so that chunking was readily available. We manipulated the association between the hiragana characters and alphabet letters (hierarchical materials: overlapped and nonoverlapped mappings). Our alphabet letter materials corresponded to the regular order within each hiragana word (within the four letters, the first and third referred to consonants, and the second and fourth referred to vowels). Only the interkeystroke intervals involved in the initiation of typing vowel letters showed an overlapping effect, which revealed that the effect was markedly large only during the early period of skill development (the effect for the overlapped mapping being larger than that for the nonoverlapped mapping), but that it had diminished by the time of late training. Conversely, the response time and the third interkeystroke interval, which are both involved in the latency of typing a consonant letter, did not reveal an overlapped effect, suggesting that chunking might be useful with hiragana characters rather than hiragana words. These results are discussed in terms of the fan effect and skill acquisition. Furthermore, we discuss whether there is a need for further research on unskilled and skilled Japanese typists.

  20. Energy spectrum of an exciton in a CdSe/ZnTe type-II core/shell spherical quantum dot

    Science.gov (United States)

    Chafai, A.; Dujardin, F.; Essaoudi, I.; Ainane, A.

    2017-01-01

    The binding energy of an exciton inside a CdSe/ZnTe core/shell spherical quantum dot was theoretically examined taking into account the dependence of the dielectric constant and charge carriers effective mass on radius, and using the envelope function approximation. Such a structure presents original optical and electronic properties because of the spatial separation of electrons and holes caused by the type-II alignment of energy states. The mean distance between the electron and hole was calculated variationally using a trial function taking into account the coulomb interaction between charge carriers. Our numerical results provide a description to the size dependence of the binding energy of an exciton inside a core/shell nanoheterostructure type-II. Indeed, by controlling the inner and outer radii, we can precisely control the energy spectrum of the exciton.

  1. Solid-phase staudinger ligation from a novel core-shell-type resin: a tool for facile condensation of small peptide fragments.

    Science.gov (United States)

    Kim, Hanyoung; Cho, Jin Ku; Aimoto, Saburo; Lee, Yoon-Sik

    2006-03-16

    [reaction: see text] Solid-phase Staudinger ligation of small peptides was performed on a novel core-shell-type resin. Solid-phase Staudinger ligation was mediated by synthetic solid-supported phosphinothiol, which was readily prepared by a straightforward synthetic route. This protocol afforded final peptide products in excellent yields and purities and thus could provide the opportunity to facilitate a simple manipulation for condensation of peptide fragments. In particular, the resulting resin could be recycled in a successful manner.

  2. Relating desorption of polycyclic aromatic hydrocarbons from harbour sludges to type of organic material

    Science.gov (United States)

    Heister, K.; Pols, S.; Loch, J. P. G.; Bosma, T.

    2009-04-01

    For decades, polycyclic aromatic hydrocarbons (PAH) cause great concern as environmental pollutants. Especially river and marine harbour sediments are frequently polluted with PAH derived from surface runoff, fuel and oil spills due to shipping and industrial activities, industrial waste and atmospheric deposition. Harbour sediments contain large amounts of organic carbon and clay minerals and are therefore not easy to remediate and have to be stored in sludge depositories after dredging to maintain sufficient water depth for shipping. The organic contaminants will be adsorbed to particles, leached in association with dissolved organic material or microbially degraded. However, compounds of high molecular weight are very persistent, particularly under anaerobic conditions, thus giving rise to the potential to become desorbed again. PAH adsorb mainly to organic material. It has been shown that components of the organic material with a low polarity and a high hydrophobicity like aliphatic and aromatic components exhibit a high sorption capacity for hydrophobic organic contaminants like PAH. Accordingly, not only the amount but also the type of organic material needs to be determined in order to be able to predict contaminant behaviour. In this study, desorption behaviour of the 16 EPA-PAH in two different harbour sludges from the port of Rotterdam, the Netherlands, has been investigated. The Beerkanaal (BK) site is located relatively close to the North Sea and represents a brackish environment; the Beneden Merwede River (BMR) site originates from a fresh water environment and is close to industrial sites. The samples were placed in dialysis membranes and brought into contact with water for a period of 130 days. At several time intervals, water samples were retrieved for analysis of pH, dissolved organic carbon (DOC) content, electrical conductivity and PAH concentrations. The experiment was conducted at 4 and at 20°C. Although the samples were initially treated with

  3. Induced magnetic ordering transition in RCo{sub 5} type materials

    Energy Technology Data Exchange (ETDEWEB)

    Rivin, Oleg, E-mail: drorivin@gmail.com [Department of Physics, Nuclear Research Center – Negev, P.O. Box 9001, Beer Sheva 84190 (Israel); Department of Physics, Ben-Gurion University, P.O. Box 653, Beer Sheva 84105 (Israel); Shaked, Hagai [Department of Physics, Ben-Gurion University, P.O. Box 653, Beer Sheva 84105 (Israel); Caspi, El’ad N. [Department of Physics, Nuclear Research Center – Negev, P.O. Box 9001, Beer Sheva 84190 (Israel)

    2015-09-15

    The magnetism in several materials of the RCo{sub 5} type is studied. A numerical calculation scheme, based on an induced magnetic ordering transition, is set up. Using this scheme, and previously reported crystalline electric and magnetic exchange fields parameters, the magnetic structure in R{sub 1−y}Y{sub y}Co{sub 3}B{sub 2} and R(Co{sub 1−x}Ni{sub x}){sub 5} materials (R=Tb and Ho), and its temperature evolution, is calculated, and compared with the corresponding observed results. It is proposed that the magnetic order in the materials of the RCO{sub 5} type, with R{sup 3+} of integral J, is driven by an induced transition. - Highlights: • A numerical calculations scheme, that simulates induced transition magnetic ordering in R{sub 1−y}YyCo{sub 3}B{sub 2} and R(Co{sub 1−x}Ni{sub x}){sub 5} type materials, is set up. • The observed ordered magnetic moment of the R sub-lattice, as function of the magnetic exchange field, and as function of temperature, is shown to agree with induced transition theory, and not with Curie–Weiss theory. • In R{sub 1−y}Y{sub y}Co{sub 3}B{sub 2}, the relative magnitudes of the crystalline electric field and the magnetic exchange field are just above the critical threshold for induced transition ordering, making them the best experimental ‘realization’ found so far.

  4. Fracture Resistance of Endodontically Treated Teeth Restored with 2 Different Fiber-reinforced Composite and 2 Conventional Composite Resin Core Buildup Materials: An In Vitro Study.

    Science.gov (United States)

    Eapen, Ashly Mary; Amirtharaj, L Vijay; Sanjeev, Kavitha; Mahalaxmi, Sekar

    2017-09-01

    The purpose of this in vitro study was to comparatively evaluate the fracture resistance of endodontically treated teeth restored with 2 fiber-reinforced composite resins and 2 conventional composite resin core buildup materials. Sixty noncarious unrestored human maxillary premolars were collected, endodontically treated (except group 1, negative control), and randomly divided into 5 groups (n = 10). Group 2 was the positive control. The remaining 40 prepared teeth were restored with various direct core buildup materials as follows: group 3 teeth were restored with dual-cure composite resin, group 4 with posterior composite resin, group 5 with fiber-reinforced composite resin, and group 6 with short fiber-reinforced composite resin. Fracture strength testing was performed using a universal testing machine. The results were statistically analyzed by 1-way analysis of variance and the post hoc Tukey test. Fracture patterns for each sample were also examined under a light microscope to determine the level of fractures. The mean fracture resistance values (in newtons) were obtained as group 1 > group 6 > group 4 > group 3 > group 5 > group 2. Group 6 showed the highest mean fracture resistance value, which was significantly higher than the other experimental groups, and all the fractures occurred at the level of enamel. Within the limitations of this study, a short fiber-reinforced composite can be used as a direct core buildup material that can effectively resist heavy occlusal forces against fracture and may reinforce the remaining tooth structure in endodontically treated teeth. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  5. Molybdate templated assembly of Ln12Mo4-type clusters (Ln = Sm, Eu, Gd) containing a truncated tetrahedron core.

    Science.gov (United States)

    Zheng, Yong; Zhang, Qian-Chong; Long, La-Sheng; Huang, Rong-Bin; Müller, Achim; Schnack, Jürgen; Zheng, Lan-Sun; Zheng, Zhiping

    2013-01-01

    Three heterometallic cluster complexes {Ln(12)Mo(4)} featuring an Ln(12) core of a distorted truncated tetrahedron were synthesized with the assistance of four MoO(4)(2-) anions as ancillary ligands. Magnetic studies of the {Gd(12)Mo(4)} cluster revealed a large magnetocaloric effect due to the presence of the large number of weakly coupled Gd(III) ions.

  6. NSGA-II Algorithm with a Local Search Strategy for Multiobjective Optimal Design of Dry-Type Air-Core Reactor

    Directory of Open Access Journals (Sweden)

    Chengfen Zhang

    2015-01-01

    Full Text Available Dry-type air-core reactor is now widely applied in electrical power distribution systems, for which the optimization design is a crucial issue. In the optimization design problem of dry-type air-core reactor, the objectives of minimizing the production cost and minimizing the operation cost are both important. In this paper, a multiobjective optimal model is established considering simultaneously the two objectives of minimizing the production cost and minimizing the operation cost. To solve the multi-objective optimization problem, a memetic evolutionary algorithm is proposed, which combines elitist nondominated sorting genetic algorithm version II (NSGA-II with a local search strategy based on the covariance matrix adaptation evolution strategy (CMA-ES. NSGA-II can provide decision maker with flexible choices among the different trade-off solutions, while the local-search strategy, which is applied to nondominated individuals randomly selected from the current population in a given generation and quantity, can accelerate the convergence speed. Furthermore, another modification is that an external archive is set in the proposed algorithm for increasing the evolutionary efficiency. The proposed algorithm is tested on a dry-type air-core reactor made of rectangular cross-section litz-wire. Simulation results show that the proposed algorithm has high efficiency and it converges to a better Pareto front.

  7. Typing of core and backbone domains of mucin-type oligosaccharides from human ovarian-cyst glycoproteins by 500-MHz 1H-NMR spectroscopy

    NARCIS (Netherlands)

    Vliegenthart, J.F.G.; Mutsaers, J.H.G.M.; Halbeek, H. van; Wu, A.M.; Kabat, E.A.

    1986-01-01

    Human blood-group A active glycoproteins from ovarian-cyst fluid were subjected to Smith degradation and subsequent beta-elimination. The resulting oligosaccharide-alditols represent the core and backbone domains of the O-linked carbohydrate chains. Nine of these, ranging in size from disaccharides

  8. Hepatitis B virus genotype C isolates with wild-type core promoter sequence replicate less efficiently than genotype B isolates but possess higher virion secretion capacity.

    Science.gov (United States)

    Qin, Yanli; Tang, Xiaoli; Garcia, Tamako; Hussain, Munira; Zhang, Jiming; Lok, Anna; Wands, Jack; Li, Jisu; Tong, Shuping

    2011-10-01

    Infection by hepatitis B virus (HBV) genotype C is associated with a prolonged viremic phase, delayed hepatitis B e antigen (HBeAg) seroconversion, and an increased incidence of liver cirrhosis and hepatocellular carcinoma compared with genotype B infection. Genotype C is also associated with the more frequent emergence of core promoter mutations, which increase genome replication and are independently associated with poor clinical outcomes. We amplified full-length HBV genomes from serum samples from Chinese and U. S. patients with chronic HBV infection and transfected circularized genome pools or dimeric constructs of individual clones into Huh7 cells. The two genotypes could be differentiated by Western blot analysis due to the reactivities of M and L proteins toward a monoclonal pre-S2 antibody and slightly different S-protein mobilities. Great variability in replication capacity was observed for both genotypes. The A1762T/G1764A core promoter mutations were prevalent in genotype C isolates and correlated with increased replication capacity, while the A1752G/T mutation frequently found in genotype B isolates correlated with a low replication capacity. Importantly, most genotype C isolates with wild-type core promoter sequence replicated less efficiently than the corresponding genotype B isolates due to less efficient transcription of the 3.5-kb RNA. However, genotype C isolates often displayed more efficient virion secretion. We propose that the low intracellular levels of viral DNA and core protein of wild-type genotype C delay immune clearance and trigger the subsequent emergence of A1762T/G1764A core promoter mutations to upregulate replication; efficient virion secretion compensates for the low replication capacity to ensure the establishment of persistent infection by genotype C.

  9. Electrochemical behaviors of a wearable woven textile Li-ion battery consisting of a core and wound electrode fibers coated with active materials

    Science.gov (United States)

    Kim, C.; Bang, S.; Zhou, D.; Yun, S.

    2017-04-01

    A new fiber-type Li-ion battery that consists of carbon nanotube fibers deposited with active materials has been developed and tested. The active materials, LiMn2O4 and Li4Ti5O12, were deposited on the surface of carbon nanotube fibers in order to use as electrodes. Tensile strength of the CNT fibers with active material was measured by tensile tests to investigate the mechanical characteristics. Electrochemical property is also measured by a battery tester during charging and discharging. The results show that current discharge capacity is about 25 mAh/g between 3.0 V and 4.2 V. That means the fiber with active materials is good for an anode electrode. Mathematical material models considering the lithium concentration and the length of Li-C bond have been established in order to predict the effective elastic modulus of electrode composite materials.

  10. 36 CFR 1290.4 - Types of materials included in scope of assassination record and additional records and information.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Types of materials included in scope of assassination record and additional records and information. 1290.4 Section 1290.4 Parks... COLLECTION ACT OF 1992 (JFK ACT) § 1290.4 Types of materials included in scope of assassination record...

  11. Damage and failure modeling of lotus-type porous material subjected to low-cycle fatigue

    Directory of Open Access Journals (Sweden)

    J. Kramberger

    2016-01-01

    Full Text Available The investigation of low-cycle fatigue behaviour of lotus-type porous material is presented in this paper. Porous materials exhibit some unique features which are useful for a number of various applications. This paper evaluates a numerical approach for determining of damage initiation and evolution of lotus-type porous material with computational simulations, where the considered computational models have different pore topology patterns. The low-cycle fatigue analysis was performed by using a damage evolution law. The damage state was calculated and updated based on the inelastic hysteresis energy for stabilized cycle. Degradation of the elastic stifness was modeled using scalar damage variable. In order to examine crack propagation path finite elements with severe damage were deleted and removed from the mesh during simulation. The direct cyclic analysis capability in Abaqus/Standard was used for low-cycle fatigue analysis to obtain the stabilized response of a model subjected to the periodic loading. The computational results show a qualitative understanding of pores topology influence on low-cycle fatigue under transversal loading conditions in relation to pore orientation.

  12. Maximum yields of microsomal-type membranes from small amounts of plant material without requiring ultracentrifugation.

    Science.gov (United States)

    Abas, Lindy; Luschnig, Christian

    2010-06-15

    Isolation of a microsomal membrane fraction is a common procedure in studies involving membrane proteins. By conventional definition, microsomal membranes are collected by centrifugation of a postmitochondrial fraction at 100,000g in an ultracentrifuge, a method originally developed for large amounts of mammalian tissue. We present a method for isolating microsomal-type membranes from small amounts of Arabidopsis thaliana plant material that does not rely on ultracentrifugation but instead uses the lower relative centrifugal force (21,000g) of a microcentrifuge. We show that the 21,000g pellet is equivalent to that obtained at 100,000g and that it contains all of the membrane fractions expected in a conventional microsomal fraction. Our method incorporates specific manipulation of sample density throughout the procedure, with minimal preclearance, minimal volumes of extraction buffer, and minimal sedimentation pathlength. These features allow maximal membrane yields, enabling membrane isolation from limited amounts of material. We further demonstrate that conventional ultracentrifuge-based protocols give submaximal yields due to losses during early stages of the procedure; that is, extensive amounts of microsomal-type membranes can sediment prematurely during the typical preclearance steps. Our protocol avoids such losses, thereby ensuring maximal yield and a representative total membrane fraction. The principles of our method can be adapted for nonplant material.

  13. Probing changes of dust properties along a chain of solar-type prestellar and protostellar cores in Taurus with NIKA

    Science.gov (United States)

    Bracco, A.; Palmeirim, P.; André, Ph.; Adam, R.; Ade, P.; Bacmann, A.; Beelen, A.; Benoît, A.; Bideaud, A.; Billot, N.; Bourrion, O.; Calvo, M.; Catalano, A.; Coiffard, G.; Comis, B.; D'Addabbo, A.; Désert, F.-X.; Didelon, P.; Doyle, S.; Goupy, J.; Könyves, V.; Kramer, C.; Lagache, G.; Leclercq, S.; Macías-Pérez, J. F.; Maury, A.; Mauskopf, P.; Mayet, F.; Monfardini, A.; Motte, F.; Pajot, F.; Pascale, E.; Peretto, N.; Perotto, L.; Pisano, G.; Ponthieu, N.; Revéret, V.; Rigby, A.; Ritacco, A.; Rodriguez, L.; Romero, C.; Roy, A.; Ruppin, F.; Schuster, K.; Sievers, A.; Triqueneaux, S.; Tucker, C.; Zylka, R.

    2017-08-01

    The characterization of dust properties in the interstellar medium is key for understanding the physics and chemistry of star formation. Mass estimates are crucial to determine gravitational collapse conditions for the birth of new stellar objects in molecular clouds. However, most of these estimates rely on dust models that need further observational constraints to capture the relevant parameter variations depending on the local environment: from clouds to prestellar and protostellar cores. We present results of a new study of dust emissivity changes based on millimeter continuum data obtained with the NIKA camera at the IRAM-30 m telescope. Observing dust emission at 1.15 mm and 2 mm allows us to constrain the dust emissivity index, β, in the Rayleigh-Jeans tail of the dust spectral energy distribution far from its peak emission, where the contribution of other parameters (i.e. dust temperature) is more important. Focusing on the Taurus molecular cloud, one of the most famous low-mass star-forming regions in the Gould Belt, we analyze the emission properties of several distinct objects in the B213 filament. This subparsec-sized region is of particular interest since it is characterized by a collection ofevolutionary stages of early star formation: three prestellar cores, two Class 0/I protostellar cores and one Class II object. We are therefore able to compare dust properties among a sequence of sources that likely derive from the same parent filament. By means of the ratio of the two NIKA channel maps, we show that in the Rayleigh-Jeans approximation, βRJ varies among the objects: it decreases from prestellar cores (βRJ 2) to protostellar cores (βRJ 1) and the Class II object (βRJ 0). For one prestellar and two protostellar cores, we produce a robust study using available Herschel data to constrain the dust temperature of the sources. By using the Abel transform inversion technique we derive accurate radial temperature profiles that allow us to obtain

  14. Characteristic of core materials in polymeric micelles effect on their micellar properties studied by experimental and dpd simulation methods.

    Science.gov (United States)

    Cheng, Furong; Guan, Xuewa; Cao, Huan; Su, Ting; Cao, Jun; Chen, Yuanwei; Cai, Mengtan; He, Bin; Gu, Zhongwei; Luo, Xianglin

    2015-08-15

    Polymeric micelles are one important class of nanoparticles for anticancer drug delivery, but the impact of hydrophobic segments on drug encapsulation and release is unclear, which deters the rationalization of drug encapsulation into polymeric micelles. This paper focused on studying the correlation between the characteristics of hydrophobic segments and encapsulation of structurally different drugs (DOX and β-carotene). Poly(ϵ-caprolactone) (PCL) or poly(l-lactide) (PLLA) were used as hydrophobic segments to synthesize micelle-forming amphiphilic block copolymers with the hydrophilic methoxy-poly(ethylene glycol) (mPEG). Both blank and drug loaded micelles were spherical in shape with sizes lower than 50 nm. PCL-based micelles exhibited higher drug loading capacity than their PLLA-based counterparts. Higher encapsulation efficiency of β-carotene was achieved compared with DOX. In addition, both doxorubicin and β-carotene were released much faster from PCL-based polymeric micelles. Dissipative particle dynamics (DPD) simulation revealed that the two drugs tended to aggregate in the core of the PCL-based micelles but disperse in the core of PLLA based micelles. In vitro cytotoxicity investigation of DOX loaded micelles demonstrated that a faster drug release warranted a more efficient cancer-killing effect. This research could serve as a guideline for the rational design of polymeric micelles for drug delivery.

  15. Physical properties of core-concrete systems: Al2O3-ZrO2 molten materials measured by aerodynamic levitation

    Science.gov (United States)

    Ohishi, Yuji; Kargl, F.; Nakamori, F.; Muta, Hiroaki; Kurosaki, Ken; Yamanaka, Shinsuke

    2017-04-01

    During a molten core-concrete interaction, molten oxides consisting of molten core materials (UO2 and ZrO2) and concrete (Al2O3, SiO2, CaO) are formed. Reliable data on the physical properties of the molten oxides will allow us to accurately predict the progression of a nuclear reactor core meltdown accident. In this study, the viscosities and densities of molten (ZrO2)x(Al2O3)1-x (x = 0.356 and 0.172) were measured using an aerodynamic levitation technique. The densities of two small samples were estimated from their masses and their volumes (calculated from recorded images of the molten samples). The droplets were forced to oscillate using speakers, and their viscosities were evaluated from the damping behaviors of their oscillations. The results showed that the viscosity of molten (ZrO2)x(Al2O3)1-x compared to that of pure molten Al2O3 is 25% lower for x = 0.172, while it is unexpectedly 20% higher for x = 0.356.

  16. Facile synthesis of birnessite-type manganese oxide nanoparticles as supercapacitor electrode materials.

    Science.gov (United States)

    Liu, Lihu; Luo, Yao; Tan, Wenfeng; Zhang, Yashan; Liu, Fan; Qiu, Guohong

    2016-11-15

    Manganese oxides are environmentally benign supercapacitor electrode materials and, in particular, birnessite-type structure shows very promising electrochemical performance. In this work, nanostructured birnessite was facilely prepared by adding dropwise NH2OH·HCl to KMnO4 solution under ambient temperature and pressure. In order to fully exploit the potential of birnessite-type manganese oxide electrode materials, the effects of specific surface area, pore size, content of K(+), and manganese average oxidation state (Mn AOS) on their electrochemical performance were studied. The results showed that with the increase of NH2OH·HCl, the Mn AOS decreased and the corresponding pore sizes and specific surface area of birnessite increased. The synthesized nanostructured birnessite showed the highest specific capacitance of 245Fg(-1) at a current density of 0.1Ag(-1) within a potential range of 0-0.9V, and excellent cycle stability with a capacitance retention rate of 92% after 3000 cycles at a current density of 1.0Ag(-1). The present work implies that specific capacitance is mainly affected by specific surface area and pore volume, and provides a new method for the facile preparation of birnessite-type manganese oxide with excellent capacitive performance.

  17. Core 3 mucin-type O-glycan restoration in colorectal cancer cells promotes MUC1/p53/miR-200c-dependent epithelial identity.

    Science.gov (United States)

    Ye, J; Wei, X; Shang, Y; Pan, Q; Yang, M; Tian, Y; He, Y; Peng, Z; Chen, L; Chen, W; Wang, R

    2017-07-24

    The attachment of cell-surface carbohydrates to proteins mediated by the amino acids serine or threonine (O-glycan) is involved in tumor metastasis; the roles of O-glycans vary depending on their structure, but the detailed mechanisms by which O-glycans trigger signaling to control tumor metastasis are largely unknown. In this study, we found that the reduced expression of core 3 synthase correlated with metastasis to lymph nodes and distant organs, resulting in poor prognosis for colorectal cancer (CRC) patients. Mechanically, we revealed that mucin-type core 3 O-glycan was synthesized at the membrane-tethered MUC1 N terminus because of core 3 synthase expression in colon cancer cells. This further inhibited the translocation of MUC1-C to the nucleus, initiated p53 gene transcription that was dependent on the inhibition of MUC1-C nucleus translocation, activated p53-mediated miR-200c expression and resulted in mesenchymal-epithelial transition (MET). Inhibition of MUC1 via small interfering RNA (siRNA) in re-expressed core 3 synthase colon cancer cells further inhibited MUC1-C nucleus translocation, increased p53 and miR-200c expression, and enhanced MET. However, inhibition of p53 via siRNA or miR-200c via miR-200c inhibitor in re-expressed core 3 synthase colon cancer cells promoted the epithelial-mesenchymal transition (EMT) in a reversible manner. Core 3 synthase mRNA levels and the p53 mRNA levels or miR-200c levels in the colon cancerous samples were positively correlated. Our findings suggest a novel mechanism linking mucin-type core 3 O-glycan to the EMT-MET plasticity of CRC cells via MUC1/p53/miR-200c-dependent signaling cascade and shed light on therapeutic strategies to treat this malignancy.Oncogene advance online publication, 24 July 2017; doi:10.1038/onc.2017.241.

  18. Nearly lattice matched all wurtzite CdSe/ZnTe type II core-shell nanowires with epitaxial interfaces for photovoltaics.

    Science.gov (United States)

    Wang, Kai; Rai, Satish C; Marmon, Jason; Chen, Jiajun; Yao, Kun; Wozny, Sarah; Cao, Baobao; Yan, Yanfa; Zhang, Yong; Zhou, Weilie

    2014-04-07

    Achieving a high-quality interface is of great importance in core-shell nanowire solar cells, as it significantly inhibits interfacial recombination and thus improves the photovoltaic performance. Combining thermal evaporation of CdSe and pulsed laser deposition of ZnTe, we successfully synthesized nearly lattice matched all wurtzite CdSe/ZnTe core-shell nanowires on silicon substrates. Comprehensive morphological and structural characterizations revealed that a wurtzite ZnTe shell layer epitaxially grows over a wurtzite CdSe core nanowire with an abrupt interface. Further optical studies confirmed a high-quality interface and demonstrated efficient charge separation induced by the type-II band alignment. A representative photovoltaic device has been demonstrated and yielded an energy-conversion efficiency of 1.7% which can be further improved by surface passivation. The all-wurtzite core-shell nanowire with an epitaxial interface offers an attractive platform to explore the piezo-phototronic effect and promises an efficient hybrid nano-sized, energy harvesting system.

  19. Spectroscopic properties of Nd3+ ion in several types of phosphate materials

    Science.gov (United States)

    Godlewska, P.; Bandrowski, Sz.; Macalik, L.; Lisiecki, R.; Ryba-Romanowski, W.; Szczygieł, I.; Ropuszyńska-Robak, P.; Hanuza, J.

    2012-05-01

    Neodymium phosphate materials were considered as possible laser media. NaNdP2O7, NaNd(PO3)4, Na3Nd(PO4)2 and Nd3(PO4)O3 phosphates have been synthesized in the solid state reaction protecting the proper conditions characteristic for the each synthesis. Structure, optical properties and vibrational characteristics for the obtained samples have been analyzed taking into account the relations between them. Considering the structure influence of the studied phosphates on their optical properties it was found that the emission efficiency, in that the lifetime in investigated phosphates was not clearly dependent on the type of structure of these materials. Significant improvement of the emission properties is observed only for the NaNd(PO3)4 metaphosphate where the longest Nd-Nd distance appears and the luminescence lifetime of the 4F3/2 level in this material was measured to be 112 μs. It means that among investigated compounds solely NaNd(PO3)4 metaphosphate can be considered as promising stoichiometric laser active material.

  20. Dual equations and solutions of I-type crack of dynamic problems in Piezoelectric materials

    Institute of Scientific and Technical Information of China (English)

    BIAN Wen-feng; WANG Biao

    2007-01-01

    This paper firstly works out basic differential equations of piezoelectric materials expressed in terms of potential functions, which are introduced in the very beginning. These equations are primarily solved through Laplace transformation, semiinfinite Fourier sine transformation and cosine transformation. Secondly, dual equations of dynamic cracks problem in 2D piezoelectric materials are established with the help of Fourier reverse transformation and the introduction of boundary conditions. Finally, according to the character of the Bessel function and by making full use of the Abel integral equation and its reverse transform, the dual equations are changed into the second type of Fredholm integral equations. The investigation indicates that the study approach taken is feasible and has potential to be an effective method to do research on issues of this kind.

  1. A note on the thermal effects upon a Gurson-type material model

    Science.gov (United States)

    Vaz, M.; Andrade Pires, F. M.

    2016-05-01

    Gurson-type material models are based on concepts of porous materials and have been largely used to describe mechanical degradation under inelastic deformation. In addition to mechanical damage, temperature evolution is also relevant to this class of problems owing to thermal softening effects. This work addresses a finite strain thermo-elastic-plastic formulation fully coupled to the energy conservation equation and investigates the sensitivity of the mechanical response with respect to the temperature evolution based on tensile tests for small to moderate temperatures. The results indicate that the initial temperature, sensitivity of the yield stress to temperature and the heat transfer coefficient at the specimen surface play an important role on the evolution of the void fraction, stress distribution and, ultimately, the load-bearing capacity.

  2. Mo/MCM-41-Type mesoporous materials doubly promoted with Fe and Ni for hydrotreating reactions

    Energy Technology Data Exchange (ETDEWEB)

    Carlos F. Linares; Patricia Amezqueta; Carlos Scott [Universidad de Carabobo, Carabobo (Venezuela). Laboratorio de Catalisis y Metales de Transicion

    2008-09-15

    A Si-MCM-41-type material was synthesized and impregnated with a Mo solution in order to get a 15% MoO{sub 3} by weight. Then, it was doubly promoted with Ni and Fe in different proportions. Information on the structure of the precursors was revealed by XRD, TPR and surface area techniques. XRD results showed that the mesoporous materials were not affected for the successive impregnations carried out; while, their specific surface areas was partially blocked. These solids were tested for vanadyl octaethyl porphyrin hydrodeporphirinization (HDP), and individual and competitive reactions of dibenzothiophene (DBT) hydrodesulfurization (HDS) and 2-methyl naphthalene (2MN) hydrogenation (HYD). The DBT HDS activity was higher than 2MN HYD, and the presence of Fe in the catalysts did not produce a synergetic effect for this reactions. However, HDP activities of doubly promoted catalysts were superior to the monopromoted ones. 28 refs., 8 figs., 5 tabs.

  3. A one-pot reaction to synthesize two types of fluorescent materials containing benzothiazolyl moiety.

    Science.gov (United States)

    Yu, Tianzhi; Zhang, Chengcheng; Zhao, Yuling; Chai, Haifang; Fan, Duowang; Ma, Ying; Yao, Shanglei; Li, Wentao

    2013-05-01

    Two different types of fluorescent materials containing benzothiazolyl moiety, 2-(benzothiazol-2-yl)phenol derivatives and 3-(benzothiazol-2-yl)coumarin derivatives, were synthesized synchronously using ethyl cyanoacetate, appropriate aromatic aldehyde and 2-aminothiophenol as the starting materials under the catalysis of benzoic acid by one-pot reaction. This method has the advantages of mild reaction conditions, easy processing and low waste. All synthesized compounds were characterized by elemental analysis, IR, (1)H NMR spectra. The structures of 2-(benzothiazol-2-yl)phenol derivatives, 2-(benzothiazol-2-yl)phenol (BTP) and 2-(benzothiazol-2-yl)naphthol (BTN), were determined by X-ray single crystal analysis. The UV-vis absorption and photoluminescence spectra of all synthesized compounds were investigated. The 2-(benzothiazol-2-yl)phenol derivatives exhibit bright green emissions and 3-(benzothiazol-2-yl)coumarin derivatives emit bright blue light in solutions.

  4. Preparation and electrochemical properties of core-shell carbon coated Mn–Sn complex metal oxide as anode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ruixue [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, Soochow University, Suzhou 215006 (China); Fang, Guoqing; Liu, Weiwei [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); Xia, Bingbo; Sun, Hongdan; Zheng, Junwei [Key Laboratory of Lithium Battery Materials of Jiangsu Province, Institute of chemical power sources, 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)

    2014-02-15

    In this study, we synthesized a carbon coated Mn–Sn metal oxide composite with core-shell structure (MTO@C) via a simple glucose hydrothermal reaction and subsequent carbonization approach. When the MTO@C composite was applied as an anode material for lithium-ion batteries, it maintained a reversible capacity of 409 mA h g{sup −1} after 200 cycles at a current density of 100 mA g{sup −1}. The uniformed and continuous carbon layer formed on the MTO nanoparticles, effectively buffered the volumetric change of the active material and increased electronic conductivity, which thus prolonged the cycling performance of the MTO@C electrode.

  5. Photochemical synthesis of bimetallic Au-Ag nanoparticles with "core-shell" type structure by seed mediated catalytic growth

    Institute of Scientific and Technical Information of China (English)

    DONG Shou-an; TANG Chun

    2005-01-01

    The colloidal Au core/Ag shell structure composite nanoparticles were synthesized in PEG-acetone solution by photochemical route. The monodispersed Au nanoparticles with average diameter of 3.9 nm were used as growth seeds. The optical property of colloids and the sizes of composite nanoparticles were characterized when the molar ratio of Au to Ag ranges from 4 : 1 to 1 : 4. The results show that a composite nanoparticle structure similar to strawberry shape is formed at the molar ratio of Au to Ag from 4 : 1 to 1 : 1; the composite nanoparticles consisting of a core of Au and shell of Ag were generated at the 1: 4 molar ratio, having a striking feature of forming interconnected network structure.

  6. THE TYPE OF PACKAGING MATERIAL AND STORAGE CONDITIONS AS FACTORS FOR WHEAT SEED QUALITY

    Directory of Open Access Journals (Sweden)

    Josip Šimenić

    2000-12-01

    Full Text Available Seed of cereal is normally grown on 5-8% of the overall plots under cereals in the Republic of Croatia. The produced seed meets the needs for high quality seed of wheat, barley, oat and other cereals. Certain quantities of seed remain unsold every year and are kept at various storage conditions and in various packaging material. The objective of this paper was to find out which storage conditions and what sort of packaging material would provide for the best viability of wheat seed. The investigation was carried out at storage simulation and by using various packaging material. In addition to well-known packaging material, such as paper 2 and 4-layer bags, jute bags, and PPR bags, the seed was also packed in the PVC transparent and PVC black bags, as well as in bags made of Aluminium foil. The investigation lasted for two years and was carried out in three various storage conditions, such as in the "New Warehouse" - a warehouse of a new type with thermal isolation in the roof and with uncontrolled conditions, ii the "Old Warehouse" made of filled-in brick and with a roof made of asbestos board, and iii under the "Eaves". The results have shown that the best seed was obtained when packed in 2 and 4-layer paper bags, PVC transparent bags and those made of Aluminium foil. Poorer results were obtained with bags of jute, polypropeline bags and PVC black bags. The storage of seed at "Eaves" has attained the best results in both years of the investigation, as compared to all three types of storage and it can in our circumstances meet the needs for wheat seed storage during one year

  7. Explosions of O-Ne-Mg Cores, the Crab Supernova, and Subluminous Type II-P Supernovae

    CERN Document Server

    Kitaura, F S; Hillebrandt, W

    2005-01-01

    We present results of simulations of stellar collapse and explosions in spherical symmetry for progenitor stars in the 8-10 solar mass range with an O-Ne-Mg core. The simulations were continued until nearly one second after core bounce and were performed with the Prometheus/Vertex code with a variable Eddington factor solver for the neutrino transport, including a state-of-the-art treatment of neutrino-matter interactions. Particular effort was made to implement nuclear burning and electron capture rates with sufficient accuracy to ensure a smooth continuation, without transients, from the progenitor evolution to core collapse. Using two different nuclear equations of state (EoSs), a soft version of the Lattimer & Swesty EoS and the significantly stiffer Wolff & Hillebrandt EoS, we found no prompt explosions, but instead delayed explosions, powered by neutrino heating and the neutrino-driven baryonic wind which sets in about 200 ms after bounce. The models eject little nickel ( 0.46, which suggests a ...

  8. Fracture resistance of endodontically treated teeth restored with short fiber composite used as a core material-An in vitro study.

    Science.gov (United States)

    Garlapati, Tejesh Gupta; Krithikadatta, Jogikalmat; Natanasabapathy, Velmurugan

    2017-03-06

    This in-vitro study tested the fracture resistance of endodontically treated molars with Mesial-Occluso-Distal (MOD) cavities restored with fibre reinforced composite material everX posterior in comparision with hybrid composite and ribbond fiber composite. Fifty intact freshly extracted human mandibular first molars were collected and were randomly divided into five groups (n=10). Group 1: positive control (PC) intact teeth without any endodontic preparation. In groups 2 through 6 after endodontic procedure standard MOD cavities were prepared and restored with their respective core materials as follows: group 2, negative control (NC) left unrestored or temporary flling was applied. Group 3, Hybrid composite (HC) as a core material (Te-Econom Plus Ivoclar Vivadent Asia) group 4, Ribbond (Ribbond; Seattle, WA, USA)+conventional composite resin (RCR) group 5, everX posterior (everX Posterior GC EUROPE)+conventional composite resin (EXP) after thermocycling fracture resistance for the samples were tested using universal testing machine. The results were analysed using ANOVA and Tukey's HSD post hoc tests. Mean fracture resistance (in Newton, N) was group 1: 1568.4±221.71N, group 2: 891.0±50.107N, group 3: 1418.3±168.71N, group 4:1716.7±199.51N and group 5: 1994.8±254.195N. Among the materials tested, endodontically treated teeth restored with everX posterior fiber reinforced composite showed superior fracture resistance. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  9. Redox tuning and species distribution in Maya Blue-type materials: a reassessment.

    Science.gov (United States)

    Doménech-Carbó, Antonio; Valle-Algarra, Francisco Manuel; Doménech-Carbó, María Teresa; Domine, Marcelo E; Osete-Cortina, Laura; Gimeno-Adelantado, José Vicente

    2013-08-28

    Maya Blue-type specimens prepared from indigo (1 wt %) plus kaolinite, montmorillonite, palygorskite, sepiolite, and silicalite are studied. Liquid chromatography with diode array detection, ultra-performance liquid chromatography coupled with mass spectrometry, and pyrolysis-silylation gas chromatography-mass spectrometry analyses of the extracts from these specimens combined with spectral and solid-state voltammetry, electrochemical impedance spectroscopy, and scanning electrochemical microscopy techniques provide evidence for the presence of a significant amount of dehydroindigo and isatin accompanying indigo and other minority organic compounds in all samples. Solid-state electrochemistry data permits the estimatation of indigo loading in archeological Maya Blue, which is in the range of 0.2 to 1.5 wt %. These results support a view of 'genuine' Maya Blue-type materials as complex polyfunctional organic-inorganic hybrids.

  10. Catalogue of the type material of Phlebotominae (Diptera, Psychodidae) deposited in the Instituto Evandro Chagas, Brazil

    Science.gov (United States)

    dos Santos, Thiago Vasconcelos; Pinheiro, Maria Sueli Barros; de Andrade, Andrey José

    2014-01-01

    Abstract The available type material of Phlebotominae (Diptera, Psychodidae) deposited in the “Coleção de Flebotomíneos” of the Instituto Evandro Chagas (ColFleb IEC) is now presented in an annotated catalogue comprising a total of 121 type specimens belonging to 12 species as follow: Nyssomyia richardwardi (2 female paratypes), Nyssomyia shawi (9 male and 25 female paratypes), Nyssomyia umbratilis (female holotype and 1 female paratype), Nyssomyia yuilli yuilli (1 male and 1 female paratypes), Pintomyia gruta (1 male and 2 female paratypes), Psychodopygus lainsoni (2 male syntypes), Psychodopygus leonidasdeanei (male holotype, female “allotype” and 45 female paratypes), Psychodopygus llanosmartinsi (2 female paratypes), Psychodopygus wellcomei (1 male and 4 female “syntypes”), Trichophoromyia readyi (male holotype, female “allotype” and 1 male paratype), Trichophoromyia adelsonsouzai (male holotype, 13 male 5 female paratypes), and Trichophoromyia brachipyga (1 male paratype). PMID:24715786

  11. OLPT CONDUCTIVITY IN WOLLASTONITE INLAID NR/SBR TYPE ELASTOMER BASED MATERIAL

    Directory of Open Access Journals (Sweden)

    E. Şentürk

    2012-07-01

    Full Text Available The electrical properties of wollastonite inlaid NR/SBR type elastomer based material have been evaluated. Electrical properties of the samples were measured in the temperature range of 303 to 453 K and the frequency range of 100 Hz – 40 MHz. All electrically measured parameters were given anomalies at 385 K. Only one type of dielectric relaxation process have been observed for all measurements. Physical parameters characterizing the dielectric behavior have been obtained by fitting the experimental results in the modified Debye equation. The activation energy which is thermally activated by dielectric relaxation process have been calculated to be 0.58 eV. DC conductivity increasing by temperature has been explained with the help of VFT model whereas the AC one has been clarified by the OLPT model.

  12. Moderating Material to Compensate the Drawback of High Minor Actinide Containing Transmutation Fuel on the Feedback Effects in SFR Cores

    Directory of Open Access Journals (Sweden)

    Bruno Merk

    2013-01-01

    Full Text Available The use of fine distributed moderating material to enhance the feedback effects and to reduce the sodium void effecting SFRs is described. The drawback on the feedback effects due to the introduction of minor actinides into SFR fuel is analyzed. The possibility of compensation of the effect of the minor actinides on the feedback effects by the use of fine distributed moderating material is demonstrated. The consequences of the introduction of fine distributed moderating material into fuel assemblies with fuel configurations foreseen for minor actinide transmutation are analyzed, and the positive effects on the transmutation efficiency are shown. Finally, the possible increase of the Americium content to improve the transmutation efficiency is discussed, the limit value of Americium is determined, and the possibilities given by an increase of the hydrogen content are analyzed.

  13. A review of irradiation effects on LWR core internal materials - IASCC susceptibility and crack growth rates of austenitic stainless steels

    Science.gov (United States)

    Chopra, O. K.; Rao, A. S.

    2011-02-01

    Austenitic stainless steels (SSs) are used extensively as structural alloys in the internal components of light water reactor (LWR) pressure vessels because of their relatively high strength, ductility, and fracture toughness. However, exposure to neutron irradiation for extended periods changes the microstructure (radiation hardening) and microchemistry (radiation-induced segregation) of these steels, and degrades their fracture properties. Irradiation-assisted stress corrosion cracking (IASCC) is another degradation process that affects LWR internal components exposed to neutron radiation. The existing data on irradiated austenitic SSs were reviewed to evaluate the effects of key parameters such as material composition, irradiation dose, and water chemistry on IASCC susceptibility and crack growth rates of these materials in LWR environments. The significance of microstructural and microchemistry changes in the material on IASCC susceptibility is also discussed. The results are used to determine (a) the threshold fluence for IASCC and (b) the disposition curves for cyclic and IASCC growth rates for irradiated SSs in LWR environments.

  14. Fabrication of Core-Shell Structural SiO2@H3[PM12O40] Material and Its Catalytic Activity

    Directory of Open Access Journals (Sweden)

    Xin Yang

    2014-01-01

    Full Text Available Through a natural tree grain template and sol-gel technology, the heterogeneous catalytic materials based on polyoxometalate compounds H3[PM12O40] encapsulating SiO2: SiO2@H3[PM12O40] (SiO2@PM12, M = W, Mo with core-shell structure had been prepared. The structure and morphology of the core-shell microspheres were characterized by the XRD, IR spectroscopy, UV-Vis absorbance, and SEM. These microsphere materials can be used as heterogeneous catalysts with high activity and stability for catalytic wet air oxidation of pollutant dyes safranine T (ST at room condition. The results show that the catalysts have excellent catalytic activity in treatment of wastewater containing 10 mg/L ST, and 94% of color can be removed within 60 min. Under different cycling runs, it is shown that the catalysts are stable under such operating conditions and the leaching tests show negligible leaching effect owing to the lesser dissolution.

  15. Piezo-phototronic Effect Enhanced UV/Visible Photodetector Based on Fully Wide Band Gap Type-II ZnO/ZnS Core/Shell Nanowire Array.

    Science.gov (United States)

    Rai, Satish C; Wang, Kai; Ding, Yong; Marmon, Jason K; Bhatt, Manish; Zhang, Yong; Zhou, Weilie; Wang, Zhong Lin

    2015-06-23

    A high-performance broad band UV/visible photodetector has been successfully fabricated on a fully wide bandgap ZnO/ZnS type-II heterojunction core/shell nanowire array. The device can detect photons with energies significantly smaller (2.2 eV) than the band gap of ZnO (3.2 eV) and ZnS (3.7 eV), which is mainly attributed to spatially indirect type-II transition facilitated by the abrupt interface between the ZnO core and ZnS shell. The performance of the device was further enhanced through the piezo-phototronic effect induced lowering of the barrier height to allow charge carrier transport across the ZnO/ZnS interface, resulting in three orders of relative responsivity change measured at three different excitation wavelengths (385, 465, and 520 nm). This work demonstrates a prototype UV/visible photodetector based on the truly wide band gap semiconducting 3D core/shell nanowire array with enhanced performance through the piezo-phototronic effect.

  16. Friction Consolidation Processing of n-Type Bismuth-Telluride Thermoelectric Material

    Science.gov (United States)

    Whalen, Scott; Jana, Saumyadeep; Catalini, David; Overman, Nicole; Sharp, Jeffrey

    2016-07-01

    Refined grain sizes and texture alignment have been shown to improve transport properties in bismuth-telluride (Bi2Te3) based thermoelectric materials. In this work we demonstrate a new approach, called friction consolidation processing (FCP), for consolidating Bi2Te3 thermoelectric powders into bulk form with a high degree of grain refinement and texture alignment. FCP is a solid-state process wherein a rotating tool is used to generate severe plastic deformation within the Bi2Te3 powder, resulting in a recrystallizing flow of material. Upon cooling, the far-from-equilibrium microstructure within the flow can be retained in the material. FCP was demonstrated on n-type Bi2Te3 feedstock powder having a -325 mesh size to form pucks with a diameter of 25.4 mm and thickness of 4.2 mm. Microstructural analysis confirmed that FCP can achieve highly textured bulk materials, with sub-micrometer grain size, directly from coarse feedstock powders in a single process. An average grain size of 0.8 μm was determined for regions of one sample and a multiple of uniform distribution (MUD) value of 15.49 was calculated for the (0001) pole figure of another sample. These results indicate that FCP can yield ultra-fine grains and textural alignment of the (0001) basal planes in Bi2Te3. ZT = 0.37 at 336 K was achieved for undoped stoichiometric Bi2Te3, which approximates literature values of ZT = 0.4-0.5. These results point toward the ability to fabricate bulk thermoelectric materials with refined microstructure and desirable texture using far-from-equilibrium FCP solid-state processing.

  17. Synthesis and Electroluminescent Properties of Julolidine-π-Juloidine Type Materials with the Bulky Adamantane Groups

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kum Hee; Yoon, Seung Soo [Sungkyunkwan Univ., Suwon (Korea, Republic of); Lee, Seok Jae; Kim, Young Kwan [Hongik Univ., Seoul (Korea, Republic of)

    2012-11-15

    A main problem of red emitting material, which contributes to their low EL performances, is the concentration quenching due to the effective self aggregation and the consequent formation of excimers. To avoid this drawback and thus improve the EL properties of red fluorescent OLED devices, many synthetic efforts have been conducted to develop new emitting materials with the structural motifs to suppress self-aggregation by the weakening intermolecular attractive interactions. Particularly, the introduction of bulky moieties in the emitters would provide the steric hindrance between emitting materials in solid state devices and thus reduce the self-aggregation. Nevertheless, EL performances of red materials still need to be improved for the practical applications. In conclusion, we designed and synthesized three julolidine-π-juloidine type emitting materials (1-3) with the bulky adamantane groups. To study their electroluminescent properties, the multilayered OLED devices with the structure of ITO/NPB (40 nm)/ADN : 1-3 (x%) (20 nm)/Alq{sub 3} (40 nm)/Liq (2 nm)/Al were fabricated. All devices using emitters 1-3 showed the efficient emissions, in which their EL performances depend on the structure of emitters sensitively. Particularly, a device using emitter 3 exhibited the efficient orange-red emission with the luminous and power efficiencies of 4.79 cd/A and 1.76 lm/W at 20 mA/cm{sup 2}, respectively. The CIE coordinates of this device was (0.57, 0.42) at 7.0 V.

  18. k-core covers and the core

    NARCIS (Netherlands)

    Sanchez-Rodriguez, E.; Borm, Peter; Estevez-Fernandez, A.; Fiestras-Janeiro, G.; Mosquera, M.A.

    2015-01-01

    This paper extends the notion of individual minimal rights for a transferable utility game (TU-game) to coalitional minimal rights using minimal balanced families of a specific type, thus defining a corresponding minimal rights game. It is shown that the core of a TU-game coincides with the core of

  19. k-core covers and the core

    NARCIS (Netherlands)

    Sanchez-Rodriguez, E.; Borm, Peter; Estevez-Fernandez, A.; Fiestras-Janeiro, G.; Mosquera, M.A.

    This paper extends the notion of individual minimal rights for a transferable utility game (TU-game) to coalitional minimal rights using minimal balanced families of a specific type, thus defining a corresponding minimal rights game. It is shown that the core of a TU-game coincides with the core of

  20. Type I band alignment in GaAs{sub 81}Sb{sub 19}/GaAs core-shell nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Xu, T. [Institut d' Electronique, de Microélectronique et de Nanotechnologies (IEMN), CNRS, UMR 8520, Département ISEN, 41 bd Vauban, 59046 Lille Cedex (France); Key Laboratory of Advanced Display and System Application, Shanghai University, 149 Yanchang Road, Shanghai 200072 (China); Wei, M. J. [Key Laboratory of Advanced Display and System Application, Shanghai University, 149 Yanchang Road, Shanghai 200072 (China); Capiod, P.; Díaz Álvarez, A.; Han, X. L.; Troadec, D.; Nys, J. P.; Berthe, M.; Lefebvre, I.; Grandidier, B., E-mail: bruno.grandidier@isen.iemn.univ-lille1.fr [Institut d' Electronique, de Microélectronique et de Nanotechnologies (IEMN), CNRS, UMR 8520, Département ISEN, 41 bd Vauban, 59046 Lille Cedex (France); Patriarche, G. [CNRS-Laboratoire de Photonique et de Nanostructures (LPN), Route de Nozay, 91460 Marcoussis (France); Plissard, S. R. [Institut d' Electronique, de Microélectronique et de Nanotechnologies (IEMN), CNRS, UMR 8520, Département ISEN, 41 bd Vauban, 59046 Lille Cedex (France); CNRS-Laboratoire d' Analyse et d' Architecture des Systèmes (LAAS), Univ. de Toulouse, 7 Avenue du Colonel Roche, F-31400 Toulouse (France); Caroff, P. [Institut d' Electronique, de Microélectronique et de Nanotechnologies (IEMN), CNRS, UMR 8520, Département ISEN, 41 bd Vauban, 59046 Lille Cedex (France); Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 0200 (Australia); and others

    2015-09-14

    The composition and band gap of the shell that formed during the growth of axial GaAs/GaAs{sub 81}Sb{sub 19}/ GaAs heterostructure nanowires have been investigated by transmission electron microscopy combined with energy dispersion spectroscopy, scanning tunneling spectroscopy, and density functional theory calculations. On the GaAs{sub 81}Sb{sub 19} intermediate segment, the shell is found to be free of Sb (pure GaAs shell) and transparent to the tunneling electrons, despite the (110) biaxial strain that affects its band gap. As a result, a direct measurement of the core band gap allows the quantitative determination of the band offset between the GaAs{sub 81}Sb{sub 19} core and the GaAs shell and identifies it as a type I band alignment.

  1. Thermal hydraulics characterization of the core and the reactor vessel type BWR; Caracterizacion termohidraulica del nucleo y de la vasija de un reactor tipo BWR

    Energy Technology Data Exchange (ETDEWEB)

    Zapata Y, M.; Lopez H, L.E. [CFE, Carretera Cardel-Nautla Km. 42.5, Municipio Alto Lucero, Veracruz (Mexico)]. e-mail: marxlenin.zapata@cfe.gob.mx

    2008-07-01

    The thermal hydraulics design of a reactor type BWR 5 as the employees in the nuclear power plant of Laguna Verde involves the coupling of at least six control volumes: Pumps jet region, Stratification region, Core region, Vapor dryer region, Humidity separator region and Reactor region. Except by the regions of the core and reactor, these control volumes only are used for design considerations and their importance as operative data source is limited. It is for that is fundamental to complement the thermal hydraulics relations to obtain major data that allow to determine the efficiency of internal components, such as pumps jet, humidity separator and vapor dryer. Like example of the previous thing, calculations are realized on the humidity of the principal vapor during starting, comparing it with the values at the moment incorporated in the data banks of the computers of process of both units. (Author)

  2. Issues of intergranular embrittlement of VVER-type nuclear reactors pressure vessel materials

    Science.gov (United States)

    Zabusov, O.

    2016-04-01

    In light of worldwide tendency to extension of service life of operating nuclear power plants - VVER-type in the first place - recently a special attention is concentrated on phenomena taking place in reactor pressure vessel materials that are able to lead to increased level of mechanical characteristics degradation (resistibility to brittle fracture) during long term of operation. Formerly the hardening mechanism of degradation (increase in the yield strength under influence of irradiation) mainly had been taken into consideration to assess pressure vessel service life limitations, but when extending the service life up to 60 years and more the non-hardening mechanism (intergranular embrittlement of the steels) must be taken into account as well. In this connection NRC “Kurchatov Institute” has initiated a number of works on investigations of this mechanism contribution to the total embrittlement of reactor pressure vessel steels. The main results of these investigations are described in this article. Results of grain boundary phosphorus concentration measurements in specimens made of first generation of VVER-type pressure vessels materials as well as VVER-1000 surveillance specimens are presented. An assessment of non-hardening mechanism contribution to the total ductile-to- brittle transition temperature shift is given.

  3. DIFFERENT TYPES OF MICROFIBRILLATED CELLULOSE AS FILLER MATERIALS IN POLYSODIUM ACRYLATE SUPERABSORBENTS

    Institute of Scientific and Technical Information of China (English)

    Mikael Larsson; Qi Zhou; Anette Larsson

    2011-01-01

    Three types of microfibrillated cellulose (MFC) with differences in structure and surface charge were used at low concentration as filler materials in polysodium acrylate superabsorbents (SAPs). The swelling of the composite hydrogels was determined in 0.9% NaCl solution as well as in deionized water. The shear modulus of the samples was determined through uniaxial compression analysis after synthesis and after swelling in 0.9% NaCl solution. Furthermore, the ability to retain filler effects after washing was investigated. The results showed that all of the investigated MFCs had a strong reinforcing effect on the shear modulus after synthesis. The filler effect on swelling and on the associated shear modulus of swollen samples showed a more complicated dependence on structure and surface charge. Finally, it was found that the filler effects were reasonably retained after washing and subsequent drying. The results confirm that MFC holds great potential as a filler material in superabsorbent applications. Furthermore, the results provide some insight on how the structural properties and surface charge of MFC will affect gel properties depending on swelling conditions. This information should be useful in evaluating the use of different types of MFC in future applications.

  4. Colony types and virulence traits of Legionella feeleii determined by exopolysaccharide materials.

    Science.gov (United States)

    Wang, Changle; Saito, Mitsumasa; Ogawa, Midori; Yoshida, Shin-Ichi

    2016-05-01

    Legionella feeleii is a Gram-negative pathogenic bacterium that causes Pontiac fever and pneumonia in humans. When L. feeleii serogroup 1 (ATCC 35072) was cultured on BCYE agar plates, two types of colonies were observed and exhibited differences in color, opacity and morphology. Since the two colony types are white rugose and brown translucent, they were termed as white rugose L. feeleii (WRLf) and brown translucent L. feeleii (BTLf), respectively. They exhibited different growth capacities in BYE broth in vitro, and it was found that WRLf could transform to BTLf. Under the electron microscope, it was observed that WRLf secreted materials which could be stained with ruthenium red, which was absent in BTLf. When U937 macrophages and HeLa cells were infected with the bacteria, WRLf manifested stronger internalization ability than BTLf. Intracellular growth in murine macrophages and Acanthamoeba cells was affected by the level of initial phagocytosis. WRLf was more resistant to human serum bactericidal action than BTLf. After being inoculated to guinea pigs, both organisms caused fever in the animals. These results suggest that ruthenium red-stained materials secreted in the surroundings may play a crucial role in determining L. feeleii colony morphology and virulence traits.

  5. EVIDENCE FOR ASYMMETRIC DISTRIBUTION OF CIRCUMSTELLAR MATERIAL AROUND TYPE Ia SUPERNOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, Francisco; Gonzalez-Gaitan, Santiago; Anderson, Joseph; Marchi, Sebastian; Gutierrez, Claudia; Hamuy, Mario; Cartier, Regis [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Pignata, Giuliano [Departamento Ciencias Fisicas, Universidad Andres Bello, Av. Republica 252, Santiago (Chile)

    2012-08-01

    We study the properties of low-velocity material in the line of sight toward nearby Type Ia supernovae (SNe Ia) that have measured late phase nebular velocity shifts (v{sub neb}), thought to be an environment-independent observable. We have found that the distribution of equivalent widths of narrow blended Na I D1 and D2 and Ca II H and K absorption lines differs significantly between those SNe Ia with negative and positive v{sub neb}, with generally stronger absorption for SNe Ia with v{sub neb} {>=} 0. A similar result had been found previously for the distribution of colors of SNe Ia, which was interpreted as a dependence of the temperature of the ejecta with viewing angle. Our work suggests that (1) a significant part of these differences in color should be attributed to extinction, (2) this extinction is caused by an asymmetric distribution of circumstellar material (CSM), and (3) the CSM absorption is generally stronger on the side of the ejecta opposite to where the ignition occurs. Since it is difficult to explain (3) via any known physical processes that occur before explosion, we argue that the asymmetry of the CSM is originated after explosion by a stronger ionizing flux on the side of the ejecta where ignition occurs, probably due to a stronger shock breakout and/or more exposed radioactive material on one side of the ejecta. This result has important implications for both progenitor and explosion models.

  6. Pyrolysis behavior of different type of materials contained in the rejects of packaging waste sorting plants.

    Science.gov (United States)

    Adrados, A; De Marco, I; Lopez-Urionabarrenechea, A; Caballero, B M; Laresgoiti, M F

    2013-01-01

    In this paper rejected streams coming from a waste packaging material recovery facility have been characterized and separated into families of products of similar nature in order to determine the influence of different types of ingredients in the products obtained in the pyrolysis process. The pyrolysis experiments have been carried out in a non-stirred batch 3.5 dm(3) reactor, swept with 1 L min(-1) N(2), at 500°C for 30 min. Pyrolysis liquids are composed of an organic phase and an aqueous phase. The aqueous phase is greater as higher is the cellulosic material content in the sample. The organic phase contains valuable chemicals as styrene, ethylbenzene and toluene, and has high heating value (HHV) (33-40 MJ kg(-1)). Therefore they could be used as alternative fuels for heat and power generation and as a source of valuable chemicals. Pyrolysis gases are mainly composed of hydrocarbons but contain high amounts of CO and CO(2); their HHV is in the range of 18-46 MJ kg(-1). The amount of COCO(2) increases, and consequently HHV decreases as higher is the cellulosic content of the waste. Pyrolysis solids are mainly composed of inorganics and char formed in the process. The cellulosic materials lower the quality of the pyrolysis liquids and gases, and increase the production of char.

  7. Robotically Assembled Aerospace Structures: Digital Material Assembly using a Gantry-Type Assembler

    Science.gov (United States)

    Trinh, Greenfield; Copplestone, Grace; O'Connor, Molly; Hu, Steven; Nowak, Sebastian; Cheung, Kenneth; Jenett, Benjamin; Cellucci, Daniel

    2017-01-01

    This paper evaluates the development of automated assembly techniques for discrete lattice structures using a multi-axis gantry type CNC machine. These lattices are made of discrete components called digital materials. We present the development of a specialized end effector that works in conjunction with the CNC machine to assemble these lattices. With this configuration we are able to place voxels at a rate of 1.5 per minute. The scalability of digital material structures due to the incremental modular assembly is one of its key traits and an important metric of interest. We investigate the build times of a 5x5 beam structure on the scale of 1 meter (325 parts), 10 meters (3,250 parts), and 30 meters (9,750 parts). Utilizing the current configuration with a single end effector, performing serial assembly with a globally fixed feed station at the edge of the build volume, the build time increases according to a scaling law of n4, where n is the build scale. Build times can be reduced significantly by integrating feed systems into the gantry itself, resulting in a scaling law of n3. A completely serial assembly process will encounter time limitations as build scale increases. Automated assembly for digital materials can assemble high performance structures from discrete parts, and techniques such as built in feed systems, parallelization, and optimization of the fastening process will yield much higher throughput.

  8. Robotically Assembled Aerospace Structures: Digital Material Assembly using a Gantry-Type Assembler

    Science.gov (United States)

    Trinh, Greenfield; Copplestone, Grace; O'Connor, Molly; Hu, Steven; Nowak, Sebastian; Cheung, Kenneth; Jenett, Benjamin; Cellucci, Daniel

    2017-01-01

    This paper evaluates the development of automated assembly techniques for discrete lattice structures using a multi-axis gantry type CNC machine. These lattices are made of discrete components called "digital materials." We present the development of a specialized end effector that works in conjunction with the CNC machine to assemble these lattices. With this configuration we are able to place voxels at a rate of 1.5 per minute. The scalability of digital material structures due to the incremental modular assembly is one of its key traits and an important metric of interest. We investigate the build times of a 5x5 beam structure on the scale of 1 meter (325 parts), 10 meters (3,250 parts), and 30 meters (9,750 parts). Utilizing the current configuration with a single end effector, performing serial assembly with a globally fixed feed station at the edge of the build volume, the build time increases according to a scaling law of n4, where n is the build scale. Build times can be reduced significantly by integrating feed systems into the gantry itself, resulting in a scaling law of n3. A completely serial assembly process will encounter time limitations as build scale increases. Automated assembly for digital materials can assemble high performance structures from discrete parts, and techniques such as built in feed systems, parallelization, and optimization of the fastening process will yield much higher throughput.

  9. Persistent Luminescence Hole-Type Materials by Design: Transition-Metal-Doped Carbon Allotrope and Carbides.

    Science.gov (United States)

    Qu, Bingyan; Zhang, Bo; Wang, Lei; Zhou, Rulong; Zeng, Xiao Cheng; Li, Liang

    2016-03-02

    Electron traps play a crucial role in a wide variety of compounds of persistent luminescence (PL) materials. However, little attention has been placed on the hole-trap-type PL materials. In this study, a novel hole-dominated persistent luminescence (PL) mechanism is predicted. The mechanism is validated in the night pearl diamond (NPD) composed of lonsdaleite with ultralong persistent luminescence (PL) (more than 72 h). The computed band structures suggest that the Fe ion dopant in lonsdaleite is responsible for the luminescence of NPD due to the desired defect levels within the band gap for electronic transition. Other possible impurity defects in lonsdaleite, such as K, Ca, Mg, Zn, or Tl dopants, or C vacancy can also serve as the hole-trap centers to enhance the PL. Among other 3d transition-metal-ion dopants considered, Cr and Mn ions are predicted to give rise to PL property. The predicted PL mechanism via transition-metal doping of lonsdaleite offers an exciting opportunity for engineering new PL materials by design.

  10. Friction Consolidation Processing of n-Type Bismuth-Telluride Thermoelectric Material

    Energy Technology Data Exchange (ETDEWEB)

    Whalen, Scott A.; Jana, Saumyadeep; Catalini, David; Overman, Nicole R.; Sharp, Jeffrey

    2016-04-13

    This work focused on the development of a new mechanical processing route, called Friction Consolidation Processing (FCP), for densifying bismuth-telluride (Bi2Te3) powders into bulk form. FCP is a solid-state process wherein a rotating tool was used to generate severe plastic deformation within the Bi2Te3 powder, resulting in a recrystallizing flow of material. Upon cooling, the non-equilibrium microstructure within the flow was locked into the material. FCP was demonstrated on -325 mesh (~44 micron) n-type Bi2Te3 feedstock powder to form pucks with 92% theoretical density having a diameter of 25.4mm and thickness of 4.2mm. FCP was shown to achieve highly textured bulk materials, with sub-micron grain size, directly from coarse particle feedstock powders in a single process. An average grain size of 0.8 microns was determined for one sample and a multiple of uniform distribution (MUD) value of 15.49 was calculated for the (0001) pole figure from another sample. These results indicate that FCP can yield highly refined grains and textural alignment of the (0001) basal planes in Bi2Te3. ZT=0.37 at 336K was achieved for undoped stoichiometric Bi2Te3, which is near the “text book” value of ZT=0.5.

  11. Challenges and Perspectives for NASICON-Type Electrode Materials for Advanced Sodium-Ion Batteries.

    Science.gov (United States)

    Chen, Shuangqiang; Wu, Chao; Shen, Laifa; Zhu, Changbao; Huang, Yuanye; Xi, Kai; Maier, Joachim; Yu, Yan

    2017-06-19

    Sodium-ion batteries (SIBs) have attracted increasing attention in the past decades, because of high overall abundance of precursors, their even geographical distribution, and low cost. Apart from inherent thermodynamic disadvantages, SIBs have to overcome multiple kinetic problems, such as fast capacity decay, low rate capacities and low Coulombic efficiencies. A special case is sodium super ion conductor (NASICON)-based electrode materials as they exhibit - besides pronounced structural stability - exceptionally high ion conductivity, rendering them most promising for sodium storage. Owing to the limiting, comparatively low electronic conductivity, nano-structuring is a prerequisite for achieving satisfactory rate-capability. In this review, we analyze advantages and disadvantages of NASICON-type electrode materials and highlight electrode structure design principles for obtaining the desired electrochemical performance. Moreover, we give an overview of recent approaches to enhance electrical conductivity and structural stability of cathode and anode materials based on NASICON structure. We believe that this review provides a pertinent insight into relevant design principles and inspires further research in this respect. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Effect of Wall Material on H– Production in a Plasma Sputter-Type Ion Source

    Directory of Open Access Journals (Sweden)

    Y. D. M. Ponce

    2004-12-01

    Full Text Available The effect of wall material on negative hydrogen ion (H– production was investigated in a multicusp plasma sputter-type ion source (PSTIS. Steady-state cesium-seeded hydrogen plasma was generated by a tungsten filament, while H– was produced through surface production using a molybdenum sputter target. Plasma parameters and H– yields were determined from Langmuir probe and Faraday cup measurements, respectively. At an input hydrogen pressure of 1.2 mTorr and optimum plasma discharge parameters Vd = –90 V and Id = –2.25 A, the plasma parameters ne was highest and T–e was lowest as determined from Langmuir probe measurements. At these conditions, aluminum generates the highest ion current density of 0.01697 mA/cm2, which is 64% more than the 0.01085 mA/cm2 that stainless steel produces. The yield of copper, meanwhile, falls between the two materials at 0.01164 mA/cm2. The beam is maximum at Vt = –125 V. Focusing is achieved at VL = –70 V for stainless steel, Vt = –60 V for aluminum, and Vt = –50 V for copper. The results demonstrate that proper selection of wall material can greatly enhance the H– production of the PSTIS.

  13. A New Type of Paper-frame Cavernous Material and Its Application in Energy Efficiency in Buildings

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper introduces a new type of paper-frame cavernous material, which is a made-up hollow material, by using silicate-cinder size to drench and daub.It possesses excellent performances such as light-weight, high-intensity, fire-resistance, sound-insulation, heat-insulation and no-pollution. Composed with concrete materials, a new type of bearing and energy-efficient block can be gained, which is a kind of excellent wall materials and has a wide application prospect.

  14. Electrospun core-shell nanofibers derived Fe-S/N doped carbon material for oxygen reduction reaction

    Science.gov (United States)

    Guo, Junxia; Niu, Qijian; Yuan, Yichun; Maitlo, Inamullh; Nie, Jun; Ma, Guiping

    2017-09-01

    One-dimensional (1D) nanomaterials have gained attention in energy conversion, storage, and catalyst due to the unique physical and chemical properties. Electrospinning is a kind of simple, versatile, and cost-effective technology to fabricate 1D functional nanofibers. Herein, electrospun polyacrylonitrile (PAN), melamine, and ferric chloride hexahydrate (FeCl3·6H2O) composite nanofibers are used as template, and polythiophene (PT) are prepared by photopolymerization technology on the surface of electrospun nanofibers as shell part of fibers. Then, the core-shell nanofibers are pyrolyzed and converted into Fe-S/N-C nanofibers, which can be used as catalysts for ORR due to the metal and S-/N-codoped structure and unique 1D structure which provided facile pathways for efficient mass transport and charge transfer. The ORR electrocatalytic ability of Fe-S/N-C nanofibers is tested and present excellent property, especially in stability and methanol crossover. The electrocatalytic ability of sample is comparable to that of 20 wt% Pt/C benchmarks. These results offer an easy pathway for exploring metal-heteroatom-codoped carbon nanofibers applicable for ORR catalyst.

  15. Spectropolarimetry of the Type Ic SN 2002ap in M74 More Evidence for Asymmetric Core Collapse

    CERN Document Server

    Wang, L; Höflich, P; Wheeler, J C; Fransson, C; Lundqvist, P; Wang, Lifan; Baade, Dietrich; Hoeflich, Peter; Fransson, Claes; Lundqvist, Peter

    2003-01-01

    High-quality spectropolarimetric data of SN 2002ap were obtained with the ESO Very Large Telescope Melipal (+ FORS1) at 3 epochs that correspond to -6, -2, and +1 days for a V maximum of 9 Feb 2002. The polarization spectra show three distinct broad features at 400, 550, and 750 nm that evolve in shape, amplitude and orientation in the Q-U plane. The continuum polarization grows from nearly zero to ~0.2 percent. The 750 nm feature is polarized at a level > 1 %. We identify the 550 and 750 nm features as Na I D and OI 777.4 nm moving at about 20,000 km/s. The blue feature may be Fe II. We interpret the polarization evolution in terms of the impact of a bipolar flow from the core that is stopped within the outer envelope of a carbon/oxygen core. Although the symmetry axis remains fixed, as the photosphere retreats by different amounts in different directions due to the asymmetric velocity flow and density distribution, geometrical blocking effects in deeper, Ca-rich layers can lead to a different dominant axis ...

  16. An experimental study on fatigue performance of cryogenic metallic materials for IMO type B tank

    Science.gov (United States)

    Lee, Jin-Sung; You, Won-Hyo; Yoo, Chang-Hyuk; Kim, Kyung-Su; Kim, Yooil

    2013-12-01

    Three materials SUS304, 9% Ni steel and Al 5083-O alloy, which are considered possible candidate for International Maritime Organization (IMO) type B Cargo Containment System, were studied. Monotonic tensile, fatigue, fatigue crack growth rate and Crack Tip Opening Displacement tests were carried out at room, intermediate low (-100 °C) and cryogenic (-163 °C) temperatures. The initial yield and tensile strengths of all materials tended to increase with decreasing temperature, whereas the change in elastic modulus was not as remarkable. The largest and smallest improvement ratio of the initial yield strengths due to a temperature reduction were observed in the SUS304 and Al 5083- O alloy, respectively. The fatigue strengths of the three materials increased with decreasing temperature. The largest increase in fatigue strength was observed in the Al 5083-O alloy, whereas the 9% Ni steel sample showed the smallest increase. In the fatigue crack growth rate test, SUS304 and Al 5083-O alloy showed a decrease in the crack propagation rate, due to decrease in temperature, but no visible improvement in da/dN was observed in the case of 9% Ni steel. In the Crack Tip Opening Displacement (CTOD) test, CTOD values were converted to critical crack length for the comparison with different thickness specimens. The critical crack length tended to decrease in the case of SUS304 and increase for the Al 5083-O alloy with decreasing temperature. In case of 9% Ni steel, change of critical crack length was not observed due to temperature decrease. In addition, the changing material properties according to the temperature of the LNG tank were analyzed according to the international code for the construction and equipment of ships carrying liquefied gases in bulk (IGC code) and the rules of classifications.

  17. Ultraviolet Spectroscopy of Type IIb Supernovae: Diversity and the Impact of Circumstellar Material

    CERN Document Server

    Ben-Ami, Sagi; Gal-Yam, Avishay; Mazzali, Paolo A; Filippenko, Alexei V; Horesh, Assaf; Matheson, Thomas; Modjaz, Maryam; Sauer, Daniel N; Silverman, Jeffrey M; Smith, Nathan; Yaron, Ofer

    2014-01-01

    We present new Hubble Space Telescope (HST) multi-epoch ultraviolet (UV) spectra of the bright Type IIb SN 2013df, and undertake a comprehensive anal- ysis of the set of four Type IIb supernovae for which HST UV spectra are available (SN 1993J, SN 2001ig, SN 2011dh, and SN 2013df). We find strong diversity in both continuum levels and line features among these objects. We use radiative-transfer models that fit the optical part of the spectrum well, and find that in three of these four events we see a UV continuum flux excess, apparently unaffected by line absorption. We hypothesize that this emission originates above the photosphere, and is related to interaction with circumstel- lar material (CSM) located in close proximity to the SN progenitor. In contrast, the spectra of SN 2001ig are well fit by single-temperature models, display weak continuum and strong reverse-fluorescence features, and are similar to spectra of radioactive 56Ni-dominated Type Ia supernovae. A comparison of the early shock-cooling comp...

  18. Core/shell-type nanorods of Tb{sup 3+}-doped LaPO{sub 4}, modified with amine groups, revealing reduced cytotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Runowski, Marcin [Adam Mickiewicz University, Department of Rare Earths, Faculty of Chemistry (Poland); Dąbrowska, Krystyna [Polish Academy of Sciences, Bacteriophage Laboratory, Institute of Immunology and Experimental Therapy (Poland); Grzyb, Tomasz [Adam Mickiewicz University, Department of Rare Earths, Faculty of Chemistry (Poland); Miernikiewicz, Paulina [Polish Academy of Sciences, Bacteriophage Laboratory, Institute of Immunology and Experimental Therapy (Poland); Lis, Stefan, E-mail: blis@amu.edu.pl [Adam Mickiewicz University, Department of Rare Earths, Faculty of Chemistry (Poland)

    2013-11-15

    A simple co-precipitation reaction between Ln{sup 3+} cations (Ln = lanthanide) and phosphate ions in the presence of polyethylene glycol (PEG), including post-treatment under hydrothermal conditions, leads to the formation of Tb{sup 3+}-doped LaPO{sub 4} crystalline nanorods. The nanoparticles obtained can be successfully coated with amorphous and porous silica, forming core/shell-type nanorods. Both products reveal intensive green luminescence under UV lamp irradiation. The surface of the core/shell-type product can also be modified with –NH{sub 2} groups via silylation procedure, using 3-aminopropyltriethoxysilane as a modifier. Powder X-ray diffraction, transmission electron microscopy, and scanning electron microscopy confirm the desired structure and needle-like shape of the products synthesized. Fourier transform infrared spectroscopy and specific surface area measurements by Brunauer–Emmett–Teller method reveal a successful surface modification with amine groups of the core/shell-type nanoparticles prepared. The nanomaterials synthesized exhibit green luminescence characteristic of Tb{sup 3+} ions, as solid powders and aqueous colloids, examined by spectrofluorometry. The in vitro cytotoxicity studies reveal different degree toxicity of the products. LaPO{sub 4}:Tb{sup 3+}@SiO{sub 2}@NH{sub 2} exhibits the smallest toxicity against B16F0 mouse melanoma cancer cells and human skin microvascular endothelial cell lines, in contrast to the most toxic LaPO{sub 4}:Tb{sup 3+}@SiO{sub 2}.Graphical Abstract.

  19. Leaning-type polar smectic-C phase in a freely suspended bent-core liquid crystal film.

    Science.gov (United States)

    Chattham, Nattaporn; Tamba, Maria-Gabriela; Stannarius, Ralf; Westphal, Eduard; Gallardo, Hugo; Prehm, Marko; Tschierske, Carsten; Takezoe, Hideo; Eremin, Alexey

    2015-03-01

    A rich variety of responsive behavior occurs in complex structured fluids due to their lower symmetries. On the other hand, fluid disorder tends to increase the symmetry of liquid crystal mesophases. Here, we report direct evidence for the existence of a mesophase with CS symmetry. The observations are based on optical studies of director inversion walls in freely suspended films in electric fields under obliquely incident light. This phase is distinguished by the polarization lying in the molecular tilt plane in freely suspended films. Such a low-symmetry polar fluid phase has been long predicted to occur in bent-core liquid crystals. The stability of this phase is attributed to the bent shape of the mesogens and dominating dispersion interactions.

  20. Tree ring growth by core sampling at the CONECOFOR Permanent Monitoring Plots. The deciduous oak (Quercus cerris L. type

    Directory of Open Access Journals (Sweden)

    Maria Chiara MANETTI

    2002-09-01

    Full Text Available Radial growth analysis evaluates the ability of trees to grow under different site and environmental conditions, thus contributing to bio-ecological studies aimed at increasing understanding of forest stand evolution. Tree ring growth is analysed in five Permanent Monitoring Plots (PMPs dominated by Turkey oak (Quercus cerris L.. Common structural features of these PMPs are their origin (coppice forest and their current physiognomy as stored coppice and transitory crop. A dendroecological approach was used to analyse past radial stem growth, the influence of silvicultural background and stand age, as well as to compare the growth rhythm of stands in different site-indexes and environmental conditions. Tree coring was carried out at the time of the first inventory (winter 1996/97 by sampling 8 to 11 dominant and co-dominant trees representative of the upper storey in the buffer area of each PMP. The basic stem and crown growth variables were measured for each tree sampled and two cores collected at 1.30 m. Annual ring width was determined by the Tree Ring Measurement System SMIL3 and the data were elaborated by the ANAFUS software. Site mean curves and growth trend per social class in each stand were defined both by visual comparison and statistical analysis among individual tree series. The main results were as follows: i social differentiation becomes established earlier with better site indexes and higher tree densities; ii sensitivity to external disturbances is higher and more defined in the dominant class than in the co-dominant tree layer; iii competition cycles are clearly discernible and related to both stand density and site-index in young stands under natural evolution (stored coppices; iv when silvicultural interventions were performed in the past is quite visible readable in the stands under conversion into high forest (transitory crops; v the mean series per site are statistically related and common periods characterized by a

  1. Application of Dredged Materials and Steelmaking Slag as Basal Media to Restore and Create Seagrass Beds: Mesocosm and Core Incubation Experiments

    Science.gov (United States)

    Tsukasaki, A.; Suzumura, M.; Tsurushima, N.; Nakazato, T.; Huang, Y.; Tanimoto, T.; Yamada, N.; Nishijima, W.

    2016-02-01

    Seagrass beds stabilize bottom sediments, improve water quality and light conditions, enhance species diversity, and provide habitat complexity in coastal marine environments. Seagrass beds are now experiencing worldwide decline by rapid environmental changes. Possible options of seagrass bed restoration are civil engineering works including mounding to raise the bottom to elevations with suitable light for seagrass growth. Reuse or recycling of dredged materials (DM) and various industrial by-products including steelmaking slags is a beneficial option to restore and create seagrass beds. To evaluate the applicability of DM and dephosphorization slag (Slag) as basal media of seagrass beds, we carried out mesocosm experiments and core incubation experiments in a land-based flow-through seawater tank over a year. During the mesocosm experiment, no difference was found in growth of eelgrass (Zostera marina L.) and macrobenthic community structures between Slag-based sediments and sand-based control experiments, even though Slag-based sediments exhibited substantially higher pH than sand-based sediments. During the core incubation experiment, we investigated detailed variation and distributions of pH and nutrients, and diffusion fluxes of nutrients between the sediment/seawater interface. Though addition of Slag induced high pH up to 10.7 in deep layers (reported in natural coastal systems. It was suggested that the mixture of Slag and DM is applicable as basal media for construction of artificial seagrass beds.

  2. Synthesis and characterization of multi-layer core-shell structural LiFeBO3/C as a novel Li-battery cathode material

    Science.gov (United States)

    Zhang, Bao; Ming, Lei; Zheng, Jun-chao; Zhang, Jia-feng; Shen, Chao; Han, Ya-dong; Wang, Jian-long; Qin, Shan-e.

    2014-09-01

    A multi-layer core-shell structural LiFeBO3/C has been successfully synthesized via spray-drying and carbothermal method using LiBO2·8H2O, Fe(NO3)3·9H2O, and citric acid as starting materials. The Rietveld refinement results indicate the sample consists of two phases: LiFeBO3 [94(6)% w/w], and LiFeO2 [6(4)% w/w]. SEM images show that the LiFeBO3 powders consist of rough similar-spherical particles with a size distribution ranging from 1 μm to 5 μm. TEM results present that the LiFeBO3 spherical particles are well coated by nano-carbon webs and form a multi-layer core-shell structure. The amount of carbon was determined to be 6.50% by C/S analysis. The prepared LiFeBO3-LiFeO2/C presents an initial discharge capacity of 196.5 mAh g-1 at the current density of 10 mA g-1 between 1.5 and 4.5 V, and it can deliver a discharge capacity of 136.1 mAh g-1 after 30 cycles, presents excellent electrochemical properties, indicating the surface sensitivity in the air was restrained.

  3. Material configurations for n-type silicon-based terahertz quantum cascade lasers

    Science.gov (United States)

    Valavanis, A.; Dinh, T. V.; Lever, L. J. M.; Ikonić, Z.; Kelsall, R. W.

    2011-05-01

    Silicon-based quantum cascade lasers (QCLs) offer the prospect of integrating coherent terahertz (THz) radiation sources with silicon microelectronics. Theoretical studies have proposed a variety of n-type SiGe-based heterostructures as design candidates; however, the optimal material configuration remains unclear. In this work, an optimization algorithm is used to design equivalent THz QCLs in three recently proposed configurations [(001) Ge/GeSi, (001) Si/SiGe, and (111) Si/SiGe], with emission frequencies of 3 and 4 THz. A systematic comparison of the electronic and optical properties is presented. A semiclassical electron transport simulation is used to model the charge carrier dynamics and calculate the peak gain, the corresponding current density, and the maximum operating temperature. It is shown that (001) Ge/GeSi structures yield the best simulated performance at both emission frequencies.

  4. Electronic structure and optical properties of a new type of semiconductor material:graphene monoxide

    Institute of Scientific and Technical Information of China (English)

    Yang Gui; Zhang Yufeng; Yan Xunwang

    2013-01-01

    The electronic and optical properties of graphene monoxide,a new type of semiconductor material,are theoretically studied by first-principles density functional theory.The calculated band structure shows that graphene monoxide is a semiconductor with a direct band gap of 0.95 eV.The density of states of graphene monoxide and the partial density of states for C and O are given to understand the electronic structure.In addition,we calculate the optical properties of graphene monoxide,including the complex dielectric function,absorption coefficient,complex refractive index,loss-function,reflectivity and conductivity.These results provide a physical basis for potential application in optoelectronic devices.

  5. The influence of storage duration on the setting time of type 1 alginate impression material

    Science.gov (United States)

    Rahmadina, A.; Triaminingsih, S.; Irawan, B.

    2017-08-01

    Alginate is one of the most commonly used dental impression materials; however, its setting time is subject to change depending on storage conditions and duration. This creates problems because consumer carelessness can affect alginate shelf life and quality. In the present study, the setting times of two groups of type I alginate with different expiry dates was tested. The first group consisted of 11 alginate specimens that had not yet passed the expiry date, and the second group consisted of alginates that had passed the expiry date. The alginate powder was mixed with distilled water, poured into a metal ring, and tested with a polished rod of poly-methyl methacrylate. Statistical analysis showed a significant difference (palginate that had not passed the expiry date (157 ± 3 seconds) and alginate that had passed the expiry date (144 ± 2 seconds). These findings indicate that storage duration can affect alginate setting time.

  6. Trapping Planetary Noble Gases During the Fischer-Tropsch-Type Synthesis of Organic Materials

    Science.gov (United States)

    Nuth, Joseph A.; Johnson, N. M.; Meshik, A.

    2010-01-01

    When hydrogen, nitrogen and CO arc exposed to amorphous iron silicate surfaces at temperatures between 500 - 900K, a carbonaceous coating forms via Fischer-Tropsch type reactions!, Under normal circumstances such a catalytic coating would impede or stop further reaction. However, we find that this coating is a better catalyst than the amorphous iron silicates that initiate these rcactions:u . The formation of a self-perpetuating catalytic coating on grain surfaces could explain the rich deposits of macromolecular carbon found in primitive meteorites and would imply that protostellar nebulae should be rich in organic materiaL Many more experiments are needed to understand this chemical system and its application to protostellar nebulae.

  7. Development and in vitro evaluation of core-shell type lipid-polymer hybrid nanoparticles for the delivery of erlotinib in non-small cell lung cancer.

    Science.gov (United States)

    Mandal, Bivash; Mittal, Nivesh K; Balabathula, Pavan; Thoma, Laura A; Wood, George C

    2016-01-01

    Core-shell type lipid-polymer hybrid nanoparticles (CSLPHNPs) have emerged as a multifunctional drug delivery platform. The delivery system combines mechanical advantages of polymeric core and biomimetic advantages of the phospholipid shell into a single platform. We report the development of CSLPHNPs composed of the lipid monolayer shell and the biodegradable polymeric core for the delivery of erlotinib, an anticancer drug, clinically used to treat non-small cell lung cancer (NSCLC). Erlotinib loaded CSLPHNPs were prepared by previously reported single-step sonication method using polycaprolactone (PCL) as the biodegradable polymeric core and phospholipid-shell composed of hydrogenated soy phosphatidylcholine (HSPC) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000 (DSPE-PEG2000). Erlotinib loaded CSLPHNPs were characterized for physicochemical properties including mean particle size, polydispersity index (PDI), zeta potential, morphology, thermal and infrared spectral analysis, drug loading, in vitro drug release, in vitro serum stability, and storage stability. The effect of critical formulation and process variables on two critical quality attributes (mean particle size and drug entrapment efficiency) of erlotinib loaded CSLPHNPs was studied and optimized. In addition, in vitro cellular uptake, luminescent cell viability assay and colony formation assay were performed to evaluate efficacy of erlotinib loaded CSLPHNPs in A549 cells, a human lung adenocarcinoma cell line. Optimized erlotinib loaded CSLPHNPs were prepared with mean particle size of about 170nm, PDI<0.2, drug entrapment efficiency of about 66% with good serum and storage stability. The evaluation of in vitro cellular efficacy results indicated enhanced uptake and efficacy of erlotinib loaded CSLPHNPs compared to erlotinib solution in A549 cells. Therefore, CSLPHNPs could be a potential delivery system for erlotinib in the therapy of NSCLC.

  8. Engineering report. Part 2: NASA wheel and brake material tradeoff study for space shuttle type environmental requirements

    Science.gov (United States)

    Bok, L. D.

    1973-01-01

    The study included material selection and trade-off for the structural components of the wheel and brake optimizing weight vs cost and feasibility for the space shuttle type application. Analytical methods were used to determine section thickness for various materials, and a table was constructed showing weight vs. cost trade-off. The wheel and brake were further optimized by considering design philosophies that deviate from standard aircraft specifications, and designs that best utilize the materials being considered.

  9. Examination of type material of two species of Litomosoides (Filarioidea : Onchocercidae, parasites from bats ; taxonomic consequences

    Directory of Open Access Journals (Sweden)

    Bain O.

    2003-09-01

    Full Text Available Type material of Litomosoides hamletti Sandground, 1934 from Glossophaga soricina soricina in Brazil and L. penai Jiménez- Quirós & Arroyo, 1 960 from Carollia perspicillata azteca in Costa Rica, was examined. The morphology of the spicules shows that these species belong to the carinii group. Their synonymy with L. guiterasi Pérez Vigueras, 1934, from Artibeus jamaicensis yucatanicus in Cuba, does not appear justified because they are distinct in several characters (body length, width of female, size and shape of buccal cavity and capsule, shape of right spicule. L. hamletti is a valid species; L. penai is closely related to it and is considered to be a sub-species, L. hamletti penai Jiménez-Quirós & Arroyo, 1960: The material recovered from Glossophaga spp., previously assigned to L guiterasi by several authors, is identified as L. h. hamletti. L. guiterasi appears to be closely related to L chandleri Esslinger, 1973; L. chitwoodi n. sp. (= Litomosoides sp. Chitwood, 1938 seems close to these species; all three are parasites of Artibeus spp.

  10. BIFURCATION OF A SHAFT WITH HYSTERETIC-TYPE INTERNAL FRICTION FORCE OF MATERIAL

    Institute of Scientific and Technical Information of China (English)

    丁千; 陈予恕

    2003-01-01

    The bifurcation of a shaft with hysteretic internal friction of material was analysed. Firstly, the differential motion equation in complex form was deduced using Hamilton principle. Then averaged equations in primary resonances were obtained using the averaging method. The stability of steady-state responses was also determined. Lastly, the bifurcations of both normal motion (synchronous whirl) and self-excited motion (nonsynchronous whirl) were investigated using the method of singularity. The study shows that by a rather large disturbance, the stability of the shaft can be lost through Hopf bifurcation in case the stability condition is not satisfied. The averaged self-excited response appears as a type of unsymmetrical bifurcation with high orders of co-dimension. The second Hopf bifurcation, which corresponds to double amplitude-modulated response, can occur as the speed of the shaft increases. Balancing the shaft carefully to decrease its unbalance level and increasing the external damping are two effective methods to avoid the appearance of the self-sustained whirl induced by the hysteretic internal friction of material.

  11. Hybrid-Type Organic Thermoelectric Materials Containing Nanoparticles as a Carrier Transport Promoter

    Science.gov (United States)

    Oshima, Keisuke; Inoue, Junta; Sadakata, Shifumi; Shiraishi, Yukihide; Toshima, Naoki

    2017-05-01

    Carbon nanotubes (CNTs) have recently received much attention as thermoelectric materials. Although the carrier mobility within a single CNT is very high, the charge carrier transport between CNTs is quite slow. We have utilized nanoparticles (NPs) for promotion of the carrier transport between CNTs for improving their thermoelectric performance. Poly(vinyl chloride) (PVC) was used as a binder of the CNTs. Thus, hybrid-type organic thermoelectric materials containing the NPs were constructed from Pd NPs, CNTs, and PVC. The thermoelectric properties were slightly improved in the three-component films by only mixing the separately-prepared Pd NPs. The NPs of a polymer complex, poly(nickel 1,1,2,2-ethenetetrathiolate) (n-PETT), were also used as a charge carrier transport promoter instead of the Pd NPs to produce n-PETT/CNT/PVC hybrid films. Treatment of the three-component films with methanol produced a high thermoelectric power factor and low thermal conductivity, resulting in a high "apparent" thermoelectric performance ( ZT ˜ 0.3 near room temperature) although the thermal conductivity was measured in the through-plane direction, which is a different direction from that for the electrical conductivity.

  12. The Influence of Specimen Type on Tensile Fracture Toughness of Rock Materials

    Science.gov (United States)

    Aliha, Mohammad Reza Mohammad; Mahdavi, Eqlima; Ayatollahi, Majid Reza

    2016-12-01

    Up to now, several methods have been proposed to determine the mode I fracture toughness of rocks. In this research, different cylindrical and disc shape samples, namely: chevron bend (CB), short rod (SR), cracked chevron notched Brazilian disc (CCNBD), and semi-circular bend (SCB) specimens were considered for investigating mode I fracture behavior of a marble rock. It is shown experimentally that the fracture toughness values of the tested rock material obtained from different test specimens are not consistent. Indeed, depending on the geometry and loading type of the specimen, noticeable discrepancies can be observed for the fracture toughness of a same rock material. The difference between the experimental mode I fracture resistance results is related to the magnitude and sign of T-stress that is dependent on the geometry and loading configuration of the specimen. For the chevron-notched samples, the critical value of T-stress corresponding to the critical crack length was determined using the finite element method. The CCNBD and SR specimens had the most negative and positive T-stress values, respectively. The dependency of mode I fracture resistance to the T-stress was shown using the extended maximum tangential strain (EMTSN) criterion and the obtained experimental rock fracture toughness data were predicted successfully with this criterion.

  13. Hybrid-Type Organic Thermoelectric Materials Containing Nanoparticles as a Carrier Transport Promoter

    Science.gov (United States)

    Oshima, Keisuke; Inoue, Junta; Sadakata, Shifumi; Shiraishi, Yukihide; Toshima, Naoki

    2016-08-01

    Carbon nanotubes (CNTs) have recently received much attention as thermoelectric materials. Although the carrier mobility within a single CNT is very high, the charge carrier transport between CNTs is quite slow. We have utilized nanoparticles (NPs) for promotion of the carrier transport between CNTs for improving their thermoelectric performance. Poly(vinyl chloride) (PVC) was used as a binder of the CNTs. Thus, hybrid-type organic thermoelectric materials containing the NPs were constructed from Pd NPs, CNTs, and PVC. The thermoelectric properties were slightly improved in the three-component films by only mixing the separately-prepared Pd NPs. The NPs of a polymer complex, poly(nickel 1,1,2,2-ethenetetrathiolate) (n-PETT), were also used as a charge carrier transport promoter instead of the Pd NPs to produce n-PETT/CNT/PVC hybrid films. Treatment of the three-component films with methanol produced a high thermoelectric power factor and low thermal conductivity, resulting in a high "apparent" thermoelectric performance (ZT ˜ 0.3 near room temperature) although the thermal conductivity was measured in the through-plane direction, which is a different direction from that for the electrical conductivity.

  14. Effects of rare earth elements on properties of AB5-type electrode materials at different temperature

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Discharge property is an important factor to evaluate electrode materials. The discharge capacity of the hydrogen-storing alloys are not only influenced by its thermodynamic property but also closely related to its dynamic property. When the temperature changes, the degrees of influence of the above-mentioned two factors on the discharge performance vary accordingly. As a consequence, adjusting compositions of the alloys to make them have good discharge performance under a relatively wide range of temperature is of great significance. On the basis of great deal of experimental investigation, the optimum combination of rare earth elements in hydrogen-storing electrode materials using at-30-55℃ is determined and the relationships between the cell parameters and discharge performance of alloys at -30℃ are discussed. Additionally, the DFEC calculation method has been improved to predict the discharge capacities, which is in good agreement with the experimental ones. This is of theoretical significance in investigating new hydrogen-storing alloys of the AB5 type.

  15. The Influence of Specimen Type on Tensile Fracture Toughness of Rock Materials

    Science.gov (United States)

    Aliha, Mohammad Reza Mohammad; Mahdavi, Eqlima; Ayatollahi, Majid Reza

    2017-03-01

    Up to now, several methods have been proposed to determine the mode I fracture toughness of rocks. In this research, different cylindrical and disc shape samples, namely: chevron bend (CB), short rod (SR), cracked chevron notched Brazilian disc (CCNBD), and semi-circular bend (SCB) specimens were considered for investigating mode I fracture behavior of a marble rock. It is shown experimentally that the fracture toughness values of the tested rock material obtained from different test specimens are not consistent. Indeed, depending on the geometry and loading type of the specimen, noticeable discrepancies can be observed for the fracture toughness of a same rock material. The difference between the experimental mode I fracture resistance results is related to the magnitude and sign of T-stress that is dependent on the geometry and loading configuration of the specimen. For the chevron-notched samples, the critical value of T-stress corresponding to the critical crack length was determined using the finite element method. The CCNBD and SR specimens had the most negative and positive T-stress values, respectively. The dependency of mode I fracture resistance to the T-stress was shown using the extended maximum tangential strain (EMTSN) criterion and the obtained experimental rock fracture toughness data were predicted successfully with this criterion.

  16. Proteomics Core

    Data.gov (United States)

    Federal Laboratory Consortium — Proteomics Core is the central resource for mass spectrometry based proteomics within the NHLBI. The Core staff help collaborators design proteomics experiments in a...

  17. Proteomics Core

    Data.gov (United States)

    Federal Laboratory Consortium — Proteomics Core is the central resource for mass spectrometry based proteomics within the NHLBI. The Core staff help collaborators design proteomics experiments in...

  18. An extended version of the SERPENT-2 code to investigate fuel burn-up and core material evolution of the Molten Salt Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Aufiero, M.; Cammi, A.; Fiorina, C. [Politecnico di Milano, Department of Energy, CeSNEF (Enrico Fermi Center for Nuclear Studies), via Ponzio, 34/3, I-20133 Milano (Italy); Leppänen, J. [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT (Finland); Luzzi, L., E-mail: lelio.luzzi@polimi.it [Politecnico di Milano, Department of Energy, CeSNEF (Enrico Fermi Center for Nuclear Studies), via Ponzio, 34/3, I-20133 Milano (Italy); Ricotti, M.E. [Politecnico di Milano, Department of Energy, CeSNEF (Enrico Fermi Center for Nuclear Studies), via Ponzio, 34/3, I-20133 Milano (Italy)

    2013-10-15

    In this work, the Monte Carlo burn-up code SERPENT-2 has been extended and employed to study the material isotopic evolution of the Molten Salt Fast Reactor (MSFR). This promising GEN-IV nuclear reactor concept features peculiar characteristics such as the on-line fuel reprocessing, which prevents the use of commonly available burn-up codes. Besides, the presence of circulating nuclear fuel and radioactive streams from the core to the reprocessing plant requires a precise knowledge of the fuel isotopic composition during the plant operation. The developed extension of SERPENT-2 directly takes into account the effects of on-line fuel reprocessing on burn-up calculations and features a reactivity control algorithm. It is here assessed against a dedicated version of the deterministic ERANOS-based EQL3D procedure (PSI-Switzerland) and adopted to analyze the MSFR fuel salt isotopic evolution. Particular attention is devoted to study the effects of reprocessing time constants and efficiencies on the conversion ratio and the molar concentration of elements relevant for solubility issues (e.g., trivalent actinides and lanthanides). Quantities of interest for fuel handling and safety issues are investigated, including decay heat and activities of hazardous isotopes (neutron and high energy gamma emitters) in the core and in the reprocessing stream. The radiotoxicity generation is also analyzed for the MSFR nominal conditions. The production of helium and the depletion in tungsten content due to nuclear reactions are calculated for the nickel-based alloy selected as reactor structural material of the MSFR. These preliminary evaluations can be helpful in studying the radiation damage of both the primary salt container and the axial reflectors.

  19. An extended version of the SERPENT-2 code to investigate fuel burn-up and core material evolution of the Molten Salt Fast Reactor

    Science.gov (United States)

    Aufiero, M.; Cammi, A.; Fiorina, C.; Leppänen, J.; Luzzi, L.; Ricotti, M. E.

    2013-10-01

    In this work, the Monte Carlo burn-up code SERPENT-2 has been extended and employed to study the material isotopic evolution of the Molten Salt Fast Reactor (MSFR). This promising GEN-IV nuclear reactor concept features peculiar characteristics such as the on-line fuel reprocessing, which prevents the use of commonly available burn-up codes. Besides, the presence of circulating nuclear fuel and radioactive streams from the core to the reprocessing plant requires a precise knowledge of the fuel isotopic composition during the plant operation. The developed extension of SERPENT-2 directly takes into account the effects of on-line fuel reprocessing on burn-up calculations and features a reactivity control algorithm. It is here assessed against a dedicated version of the deterministic ERANOS-based EQL3D procedure (PSI-Switzerland) and adopted to analyze the MSFR fuel salt isotopic evolution. Particular attention is devoted to study the effects of reprocessing time constants and efficiencies on the conversion ratio and the molar concentration of elements relevant for solubility issues (e.g., trivalent actinides and lanthanides). Quantities of interest for fuel handling and safety issues are investigated, including decay heat and activities of hazardous isotopes (neutron and high energy gamma emitters) in the core and in the reprocessing stream. The radiotoxicity generation is also analyzed for the MSFR nominal conditions. The production of helium and the depletion in tungsten content due to nuclear reactions are calculated for the nickel-based alloy selected as reactor structural material of the MSFR. These preliminary evaluations can be helpful in studying the radiation damage of both the primary salt container and the axial reflectors.

  20. Core/Double-Shell Type Gradient Ni-Rich LiNi0.76Co0.10Mn0.14O2 with High Capacity and Long Cycle Life for Lithium-Ion Batteries.

    Science.gov (United States)

    Liao, Jin-Yun; Oh, Seung-Min; Manthiram, Arumugam

    2016-09-21

    A concentration-gradient Ni-rich LiNi0.76Co0.1Mn0.14O2 layered oxide cathode has been developed by firing a core/double-shell [Ni0.9Co0.1]0.4[Ni0.7Co0.1Mn0.2]0.5[Ni0.5Co0.1Mn0.4]0.1(OH)2 hydroxide precursor with LiOH·H2O, where the Ni-rich interior (core) delivers high capacity and the Mn-rich exterior (shells) provides a protection layer to improve the cyclability and thermal stability for the Ni-rich oxide cathodes. The content of nickel and manganese, respectively, decreases and increases gradually from the center to the surface of each gradient sample particle, offering a high capacity with enhanced surface/structural stability and cyclability. The obtained concentration-gradient oxide cathode exhibits high-energy density with long cycle life in both half and full cells. With high-loading electrode half cells, the concentration-gradient sample delivers 3.3 mA h cm(-2) with 99% retention after 100 cycles. The material morphology, phase, and gradient structure are also maintained after cycling. The pouch-type full cells fabricated with a graphite anode delivers high capacity with 89% capacity retention after 500 cycles at C/3 rate.

  1. Evaluation of cage micro-environment of mice housed on various types of bedding materials

    Science.gov (United States)

    Smith, E.; Stockwell, J.D.; Schweitzer, I.; Langley, S.H.; Smith, A.L.

    2004-01-01

    A variety of environmental factors can affect the outcomes of studies using laboratory rodents. One such factor is bedding. Several new bedding materials and processing methods have been introduced to the market in recent years, but there are few reports of their performance. In the studies reported here, we have assessed the cage micro-environment (in-cage ammonia levels, temperature, and humidity) of mice housed on various kinds of bedding and their combinations. We also compared results for bedding supplied as Nestpaks versus loose bedding. We studied C57BL/6J mice (commonly used) and NOD/LtJ mice (heavy soilers) that were maintained, except in one study, in static duplex cages. In general, we observed little effect of bedding type on in-cage temperature or humidity; however, there was considerable variation in ammonia concentrations. The lowest ammonia concentrations occurred in cages housing mice on hardwood bedding or a mixture of corncob and alpha cellulose. In one experiment comparing the micro-environments of NOD/LtJ male mice housed on woodpulp fiber bedding in static versus ventilated caging, we showed a statistically significant decrease in ammonia concentrations in ventilated cages. Therefore, our data show that bedding type affects the micro-environment in static cages and that effects may differ for ventilated cages, which are being used in vivaria with increasing frequency.

  2. Practical Thermal Evaluation Methods For HAC Fire Analysis In Type B Radiaoactive Material (RAM) Packages

    Energy Technology Data Exchange (ETDEWEB)

    Abramczyk, Glenn; Hensel, Stephen J; Gupta, Narendra K.

    2013-03-28

    Title 10 of the United States Code of Federal Regulations Part 71 for the Nuclear Regulatory Commission (10 CFR Part 71.73) requires that Type B radioactive material (RAM) packages satisfy certain Hypothetical Accident Conditions (HAC) thermal design requirements to ensure package safety during accidental fire conditions. Compliance with thermal design requirements can be met by prototype tests, analyses only or a combination of tests and analyses. Normally, it is impractical to meet all the HAC using tests only and the analytical methods are too complex due to the multi-physics non-linear nature of the fire event. Therefore, a combination of tests and thermal analyses methods using commercial heat transfer software are used to meet the necessary design requirements. The authors, along with his other colleagues at Savannah River National Laboratory in Aiken, SC, USA, have successfully used this 'tests and analyses' approach in the design and certification of several United States' DOE/NNSA certified packages, e.g. 9975, 9977, 9978, 9979, H1700, and Bulk Tritium Shipping Package (BTSP). This paper will describe these methods and it is hoped that the RAM Type B package designers and analysts can use them for their applications.

  3. Irradiation-induced structural changes in surveillance material of VVER 440-type weld metal

    Science.gov (United States)

    Grosse, M.; Denner, V.; Böhmert, J.; Mathon, M.-H.

    2000-01-01

    The irradiation-induced microstructural changes in surveillance materials of the VVER 440-type weld metal Sv-10KhMFT were investigated by small angle neutron scattering (SANS) and anomalous small angle X-ray scattering (SAXS). Due to the high fluence, a strong effect was found in the SANS experiment. No significant effect of the irradiation is detected by SAXS. The reason for this discrepancy is the different scattering contrast of irradiation-induced defects for neutrons and X-rays. An analysis of the SAXS shows that the scattering intensity is mainly caused by vanadium-containing (VC) precipitates and grain boundaries. Both types of scattering defects are hardly changed by irradiation. Neutron irradiation rather produces additional scattering defects of a few nanometers in size. Assuming these defects are clusters containing copper and other foreign atoms with a composition according to results of atom probe field ion microscopy (APFIM) investigations, both the high SANS and the low SAXS effect can be explained.

  4. Making an Ice Core.

    Science.gov (United States)

    Kopaska-Merkel, David C.

    1995-01-01

    Explains an activity in which students construct a simulated ice core. Materials required include only a freezer, food coloring, a bottle, and water. This hands-on exercise demonstrates how a glacier is formed, how ice cores are studied, and the nature of precision and accuracy in measurement. Suitable for grades three through eight. (Author/PVD)

  5. Influence of the type of vegetable oil on the drug release profile from lipid-core nanocapsules and in vivo genotoxicity study.

    Science.gov (United States)

    Rigo, Lucas Almeida; Frescura, Viviane; Fiel, Luana; Coradini, Karine; Ourique, Aline Ferreira; Emanuelli, Tatiana; Quatrin, Andréia; Tedesco, Solange; Silva, Cristiane B da; Guterres, Silvia Staniçuaski; Pohlmann, Adriana Raffin; Beck, Ruy Carlos Ruver

    2014-11-01

    The use of rice bran (RB), soybean (SB) or sunflower seed (SF) oils to prepare lipid-core nanocapsules (LNCs) as controlled drug delivery systems was investigated. LNCs were prepared by interfacial deposition using the preformed polymer method. All formulations showed negative zeta potential and adequate nanotechnological characteristics (particle size 220-230  nm, polydispersity index oils did not present genotoxic potential. Clobetasol propionate (CP) was selected as a model drug to evaluate the influence of the type of vegetable oil on the control of the drug release from LNCs. Biphasic drug release profiles were observed for all formulations. After 168  h, the concentration of drug released from the formulation containing SF oil was lower (0.36  mg/mL) than from formulations containing SB (0.40  mg/mL) or RB oil (0.45  mg/mL). Good correlations between the consistency indices for the LNC cores and the burst and sustained drug release rate constants were obtained. Therefore, the type of the vegetal oil was shown as an important factor governing the control of drug release from LNCs.

  6. Improving Photovoltaic Performance of the Linear A-Ar-A-type Small Molecules with Diketopyrropyrrole Arms by Tuning the Linkage Position of the Anthracene Core.

    Science.gov (United States)

    Duan, Xiongwei; Xiao, Manjun; Chen, Jianhua; Wang, Xiangdong; Peng, Wenhong; Duan, Linrui; Tan, Hua; Lei, Gangtie; Yang, Renqiang; Zhu, Weiguo

    2015-08-26

    Two isomeric A-Ar-A-type small molecules of DPP2An(9,10) and DPP2An(2,6), were synthesized with two acceptor arms of diketopyrropyrroles (DPP) and a planar aryl hydrocarbon core of the different substituted anthracene (An), respectively. Their thermal stability, crystallinity, optoelectronic, and photovoltaic performances were investigated. Significantly red-shifted absorption profile and higher HOMO level were observed for the DPP2An(2,6) with 2,6-substituted anthracene relative to the DPP2An(9,10) with 9,10-substituted anthracene, as the former exhibited better planarity and a larger conjugate system. As a result, the solution-processing solar cells based on DPP2An(2,6) and PC71BM (w/w,1:1) displayed remarkably increased power conversion efficiency of 5.44% and short-circuit current density (Jsc) of 11.90 mA/cm(2) under 1% 1,8-diiodooctane additive. The PCE and Jsc values were 3.7 and 2.9 times those of the optimized DPP2An(9,10)-based cells, respectively. This work demonstrates that changing the linkage position of the anthracene core in the A-Ar-A-type SMs can strongly improve the photovoltaic properties in organic solar cells.

  7. Review on the Raman spectroscopy of different types of layered materials.

    Science.gov (United States)

    Zhang, Xin; Tan, Qing-Hai; Wu, Jiang-Bin; Shi, Wei; Tan, Ping-Heng

    2016-03-28

    Two-dimensional layered materials, such as graphene and transition metal dichalcogenides (TMDs), have been under intensive investigation. The rapid progress of research on graphene and TMDs is now stimulating the exploration of different types of layered materials (LMs). Raman spectroscopy has shown its great potential in the characterization of layer numbers, interlayer coupling and layer-stacking configurations and will benefit the future explorations of other LMs. Lattice vibrations or Raman spectra of many LMs in bulk have been discussed since the 1960s. However, different results were obtained because of differences or limitations in the Raman instruments at early stages. The developments of modern Raman spectroscopy now allow us to revisit the Raman spectra of these LMs under the same experimental conditions. Moreover, to the best of our knowledge, there were limitations in detailed reviews on the Raman spectra of these different LMs. Here, we provide a review on Raman spectra of various LMs, including semiconductors, topological insulators, insulators, semi-metals and superconductors. We firstly introduce a unified method based on symmetry analysis and polarization measurements to assign the observed Raman modes and characterize the crystal structure of different types of LMs. Then, we revisit and update the positions and assignments of vibration modes by re-measuring the Raman spectra of different types of LMs and by comparing our results to those reported in previous papers. We apply the recent advances on the interlayer vibrations of graphene and TMDs to these various LMs and obtain their shear modulus. The observation of the shear modes of LMs in bulk facilitates an accurate and fast characterization of layer numbers during preparation processes in the future by a robust layer-number dependency on the frequencies of the shear modes. We also summarize the recent advances on the layer-stacking dependence on the intensities of interlayer shear vibrations

  8. Engineered inorganic core/shell nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Mélinon, Patrice, E-mail: patrice.melinon@univ-lyon1.fr [Institut Lumière matière Université Claude Bernard Lyon 1 et CNRS et OMNT, Domaine Scientifique de la Doua, Bâtiment Léon Brillouin, 43 Boulevard du 11 Novembre 1918, F 69622 Villeurbanne (France); Begin-Colin, Sylvie [IPCMS et OMNT, 23 rue du Loess BP 43, 67034 STRASBOURG Cedex 2 (France); Duvail, Jean Luc [IMN UMR 6502 et OMNT Campus Sciences : 2 rue de la Houssinire, BP32229, 44322 Nantes Cedex3 (France); Gauffre, Fabienne [SPM et OMNT : Institut des sciences chimiques de Rennes - UMR 6226, 263 Avenue du General Leclerc, CS 74205, 35042 RENNES Cedex (France); Boime, Nathalie Herlin [IRAMIS-NIMBE, Laboratoire Francis Perrin (CEA CNRS URA 2453) et OMNT, Bat 522, CEA Saclay, 91191 Gif sur Yvette Cedex (France); Ledoux, Gilles [Institut Lumière Matière Université Claude Bernard Lyon 1 et CNRS et OMNT, Domaine Scientifique de la Doua, Bâtiment Alfred Kastler 43 Boulevard du 11 Novembre 1918 F 69622 Villeurbanne (France); Plain, Jérôme [Universit de technologie de Troyes LNIO-ICD, CNRS et OMNT 12 rue Marie Curie - CS 42060 - 10004 Troyes cedex (France); Reiss, Peter [CEA Grenoble, INAC-SPrAM, UMR 5819 CEA-CNRS-UJF et OMNT, Grenoble cedex 9 (France); Silly, Fabien [CEA, IRAMIS, SPEC, TITANS, CNRS 2464 et OMNT, F-91191 Gif sur Yvette (France); Warot-Fonrose, Bénédicte [CEMES-CNRS, Université de Toulouse et OMNT, 29 rue Jeanne Marvig F 31055 Toulouse (France)

    2014-10-20

    It has been for a long time recognized that nanoparticles are of great scientific interest as they are effectively a bridge between bulk materials and atomic structures. At first, size effects occurring in single elements have been studied. More recently, progress in chemical and physical synthesis routes permitted the preparation of more complex structures. Such structures take advantages of new adjustable parameters including stoichiometry, chemical ordering, shape and segregation opening new fields with tailored materials for biology, mechanics, optics magnetism, chemistry catalysis, solar cells and microelectronics. Among them, core/shell structures are a particular class of nanoparticles made with an inorganic core and one or several inorganic shell layer(s). In earlier work, the shell was merely used as a protective coating for the core. More recently, it has been shown that it is possible to tune the physical properties in a larger range than that of each material taken separately. The goal of the present review is to discuss the basic properties of the different types of core/shell nanoparticles including a large variety of heterostructures. We restrict ourselves on all inorganic (on inorganic/inorganic) core/shell structures. In the light of recent developments, the applications of inorganic core/shell particles are found in many fields including biology, chemistry, physics and engineering. In addition to a representative overview of the properties, general concepts based on solid state physics are considered for material selection and for identifying criteria linking the core/shell structure and its resulting properties. Chemical and physical routes for the synthesis and specific methods for the study of core/shell nanoparticle are briefly discussed.

  9. Thermodynamic stability of perovskite and lanthanum nickelate-type cathode materials for solid oxide fuel cells

    Science.gov (United States)

    Cetin, Deniz

    The need for cleaner and more efficient alternative energy sources is becoming urgent as concerns mount about climate change wrought by greenhouse gas emissions. Solid oxide fuel cells (SOFCs) are one of the most efficient options if the goal is to reduce emissions while still operating on fossil energy resources. One of the foremost problems in SOFCs that causes efficiency loss is the polarization resistance associated with the oxygen reduction reaction(ORR) at the cathodes. Hence, improving the cathode design will greatly enhance the overall performance of SOFCs. Lanthanum nickelate, La2NiO4+delta (LNO), is a mixed ionic and electronic conductor that has competitive surface oxygen exchange and transport properties and excellent electrical conductivity compared to perovskite-type oxides. This makes it an excellent candidate for solid oxide fuel cell (SOFC) applications. It has been previously shown that composites of LNO with Sm0.2Ce0.8O2-delta (SDC20) as cathode materials lead to higher performance than standalone LNO. However, in contact with lanthanide-doped ceria, LNO decomposes resulting in free NiO and ceria with higher lanthanide dopant concentration. In this study, the aforementioned instability of LNO has been addressed by compositional tailoring of LNO: lanthanide doped ceria (LnxCe 1-xO2,LnDC)composite. By increasing the lanthanide dopant concentration in the ceria phase close to its solubility limit, the LNO phase has been stabilized in the LNO:LnDC composites. Electrical conductivity of the composites as a function of LNO volume fraction and temperature has been measured, and analyzed using a resistive network model which allows the identification of a percolation threshold for the LNO phase. The thermomechanical compatibility of these composites has been investigated with SOFC systems through measurement of the coefficients of thermal expansion. LNO:LDC40 composites containing LNO lower than 50 vol%and higher than 40 vol% were identified as being

  10. Behind the Final Grade in Hybrid v. Traditional Courses: Comparing Student Performance by Assessment Type, Core Competency, and Course Objective

    Science.gov (United States)

    Bain, Lisa Z.

    2012-01-01

    There are many different delivery methods used by institutions of higher education. These include traditional, hybrid, and online course offerings. The comparisons of these typically use final grade as the measure of student performance. This research study looks behind the final grade and compares student performance by assessment type, core…

  11. Cascading electron and hole transfer dynamics in a CdS/CdTe core-shell sensitized with bromo-pyrogallol red (Br-PGR): slow charge recombination in type II regime.

    Science.gov (United States)

    Maity, Partha; Debnath, Tushar; Chopra, Uday; Ghosh, Hirendra Nath

    2015-02-14

    Ultrafast cascading hole and electron transfer dynamics have been demonstrated in a CdS/CdTe type II core-shell sensitized with Br-PGR using transient absorption spectroscopy and the charge recombination dynamics have been compared with those of CdS/Br-PGR composite materials. Steady state optical absorption studies suggest that Br-PGR forms strong charge transfer (CT) complexes with both the CdS QD and CdS/CdTe core-shell. Hole transfer from the photo-excited QD and QD core-shell to Br-PGR was confirmed by both steady state and time-resolved emission spectroscopy. Charge separation was also confirmed by detecting electrons in the conduction band of the QD and the cation radical of Br-PGR as measured from femtosecond transient absorption spectroscopy. Charge separation in the CdS/Br-PGR composite materials was found to take place in three different pathways, by transferring the photo-excited hole of CdS to Br-PGR, electron injection from the photo-excited Br-PGR to the CdS QD, and direct electron transfer from the HOMO of Br-PGR to the conduction band of the CdS QD. However, in the CdS/CdTe/Br-PGR system hole transfer from the photo-excited CdS to Br-PGR and electron injection from the photo-excited Br-PGR to CdS take place after cascading through the CdTe shell QD. Charge separation also takes place via direct electron transfer from the Br-PGR HOMO to the conduction band of CdS/CdTe. Charge recombination (CR) dynamics between the electron in the conduction band of the CdS QD and the Br-PGR cation radical were determined by monitoring the bleach recovery kinetics. The CR dynamics were found to be much slower in the CdS/CdTe/Br-PGR system than in the CdS/Br-PGR system. The formation of the strong CT complex and the separation of charges cascading through the CdTe shell help to slow down charge recombination in the type II regime.

  12. Post-processor for simulations of the ORIGEN program and calculation of the composition of the activity of a burnt fuel core by a BWR type reactor; Post-procesador para simulaciones del programa ORIGEN y calculo de la composicion de la actividad de un nucleo de combustible quemado por un reactor tipo BWR

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval V, S. [IIE, Av. Reforma 113, Col. Palmira, 62490 Cuernavaca, Morelos (Mexico)]. e-mail: sandoval@iie.org.mx

    2006-07-01

    The composition calculation and the activity of nuclear materials subject to processes of burnt, irradiation and decay periods are of utility for diverse activities inside the nuclear industry, as they are it: the processes design and operations that manage radioactive material, the calculation of the inventory and activity of a core of burnt nuclear fuel, for studies of type Probabilistic Safety Analysis (APS), as well as for regulation processes and licensing of nuclear facilities. ORIGEN is a program for computer that calculates the composition and the activity of nuclear materials subject to periods of burnt, irradiation and decay. ORIGEN generates a great quantity of information whose processing and analysis are laborious, and it requires thoroughness to avoid errors. The automation of the extraction, conditioning and classification of that information is of great utility for the analyst. By means of the use of the post-processor presented in this work it is facilitated, it speeds up and wide the capacity of analysis of results, since diverse consultations with several classification options and filtrate of results can be made. As illustration of the utility of the post-processor, and as an analysis of interest for itself, it is also presented in this work the composition of the activity of a burned core in a BWR type reactor according to the following classification criteria: by type of radioisotope (fission products, activation products and actinides), by specie type (gassy, volatile, semi-volatile and not volatile), by element and by chemical group. The results show that the total activity of the studied core is dominated by the fission products and for the actinides, in proportion four to one, and that the gassy and volatile species conform a fifth part of the total activity of the core. (Author)

  13. Dynamic symmetrical pattern projection based laser triangulation sensor for precise surface position measurement of various material types.

    Science.gov (United States)

    Žbontar, Klemen; Mihelj, Matjaž; Podobnik, Boštjan; Povše, Franc; Munih, Marko

    2013-04-20

    This paper describes a custom, material-type-independent laser-triangulation-based measurement system that utilizes a high-quality ultraviolet laser beam. Laser structuring applications demand material surface alignment regarding the laser focus position, where fabrication conditions are optimal. Robust alignment of various material types was solved by introducing dynamic symmetrical pattern projection, and a "double curve fitting" centroid detection algorithm with subsurface scattering compensation. Experimental results have shown that the measurement system proves robust to laser intensity variation, with measurement bias lower than 50 μm and standard deviation lower than ±6.3 μm for all materials. The developed probe has been integrated into a PCB prototyping system for material referencing purposes.

  14. Physics and measurements of magnetic materials

    CERN Document Server

    Sgobba, S

    2010-01-01

    Magnetic materials, both hard and soft, are used extensively in several components of particle accelerators. Magnetically soft iron-nickel alloys are used as shields for the vacuum chambers of accelerator injection and extraction septa; Fe-based material is widely employed for cores of accelerator and experiment magnets; soft spinel ferrites are used in collimators to damp trapped modes; innovative materials such as amorphous or nanocrystalline core materials are envisaged in transformers for high-frequency polyphase resonant convertors for application to the International Linear Collider (ILC). In the field of fusion, for induction cores of the linac of heavy-ion inertial fusion energy accelerators, based on induction accelerators requiring some 107 kg of magnetic materials, nanocrystalline materials would show the best performance in terms of core losses for magnetization rates as high as 105 T/s to 107 T/s. After a review of the magnetic properties of materials and the different types of magnetic behaviour...

  15. Influence of weight and type of planting material on fruit quality and its heterogeneity in pineapple [Ananas comosus (L.) Merrill].

    Science.gov (United States)

    Fassinou Hotegni, V Nicodème; Lommen, Willemien J M; Agbossou, Euloge K; Struik, Paul C

    2014-01-01

    Cultural practices can affect the quality of pineapple fruits and its variation. The objectives of this study were to investigate (a) effects of weight class and type of planting material on fruit quality, heterogeneity in quality and proportion and yield of fruits meeting European export standards, and (b) the improvement in quality, proportion and yield of fruits meeting export standards when flowering was induced at optimum time. Experiments were conducted in Benin with cvs Sugarloaf (a Perola type) and Smooth Cayenne. In cv. Sugarloaf, experimental factors were weight class of planting material (light, mixed, heavy) and time of flowering induction (farmers', optimum) (Experiment 1). In cv. Smooth Cayenne an additional experimental factor was the type of planting material (hapas, ground suckers, a mixture of the two) (Experiment 2). Fruits from heavy planting material had higher infructescence and fruit weights, longer infructescences, shorter crowns, and smaller crown: infructescence length than fruits from light planting material. The type of planting material in Experiment 2 did not significantly affect fruit quality except crown length: fruits from hapas had shorter crowns than those from ground suckers. Crops from heavy planting material had a higher proportion and yield of fruits meeting export standards than those from other weight classes in Experiment 1 only; also the type of planting material in Experiment 2 did not affect these variates. Heterogeneity in fruit quality was usually not reduced by selecting only light or heavy planting material instead of mixing weights; incidentally the coefficient of variation was significantly reduced in fruits from heavy slips only. Heterogeneity was also not reduced by not mixing hapas and ground suckers. Flowering induction at optimum time increased the proportion and yield of fruits meeting export standards in fruits from light and mixed slip weights and in those from the mixture of heavy hapas plus ground suckers.

  16. Study of the interocclusal distortion in impressions taken with different types of closed-mouth trays and two types of impression materials.

    Science.gov (United States)

    Mañes-Ferrer, José-Félix; Selva-Otaolaurruchi, Eduardo-José; Parra-Arenós, Carmina; Selfa-Bas, Isabel

    2010-01-01

    The aim of this study was to compare different types of impression trays for the closed-mouth impression technique, using two different types of impression material. For this study, five different types of impression trays were used with two different types of impression materials, one of addition silicone and the other of polyether. We designed a model used for taking the impressions and for measuring interocclusal distortion. The results obtained show that the impression trays COE (GC (R) GC America INC. Alsip) and Premier (Premier (R), Premier Dental Products Co. Canada) show a lesser degree of interocclusal distortion when taking closed-mouth impressions. In terms of impression materials, the polyether was the one that produced the best results. From a clinical point of view, our study shows that the use of these types of trays is absolutely recommendable when used according to the clinical indications for which they have been designed; that said, we must not fail to consider that selecting the proper type of tray is also important.

  17. Self-Assembled Core-Shell-Type Lipid-Polymer Hybrid Nanoparticles: Intracellular Trafficking and Relevance for Oral Absorption.

    Science.gov (United States)

    Li, Qiuxia; Xia, Dengning; Tao, Jinsong; Shen, Aijun; He, Yuan; Gan, Yong; Wang, Chi

    2017-10-01

    Lipid-polymer hybrid nanoparticles (NPs) are advantageous for drug delivery. However, their intracellular trafficking mechanism and relevance for oral drug absorption are poorly understood. In this study, self-assembled core-shell lipid-polymer hybrid NPs made of poly(lactic-co-glycolic acid) (PLGA) and various lipids were developed to study their differing intracellular trafficking in intestinal epithelial cells and their relevance for oral absorption of a model drug saquinavir (SQV). Our results demonstrated that the endocytosis and exocytosis of hybrid NPs could be changed by varying the kind of lipid. A glyceride mixture (hybrid NPs-1) decreased endocytosis but increased exocytosis in Caco-2 cells, whereas the phospholipid (E200) (hybrid NPs-2) decreased endocytosis but exocytosis was unaffected as compared with PLGA nanoparticles. The transport of hybrid NPs-1 in cells involved various pathways, including caveolae/lipid raft-dependent endocytosis, and clathrin-mediated endocytosis and macropinocytosis, which was different from the other groups of NPs that involved only caveolae/lipid raft-dependent endocytosis. Compared with that of the reference formulation (nanoemulsion), the oral absorption of SQV-loaded hybrid NPs in rats was poor, probably due to the limited drug release and transcytosis of NPs across the intestinal epithelium. In conclusion, the intracellular processing of hybrid NPs in intestinal epithelia can be altered by adding lipids to the NP. However, it appears unfavorable to use PLGA-based NPs to improve oral absorption of SQV compared with nanoemulsion. Our findings will be essential in the development of polymer-based NPs for the oral delivery of drugs with the purpose of improving their oral absorption. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  18. Experimental Investigation on Regenerator Materials of Stirling-type Pulse-tube Refrigerator Working at 20 K

    Science.gov (United States)

    Zhou, Qiang; Chen, Liubiao; Pan, Changzhao; Zhou, Yuan; Wang, Junjie

    This paper will introduce our recent experimental results of cryogenic regenerator materials employed in Stirling-type one-stage pulse-tube refrigerator for the use at liquid hydrogen temperature. Thermal diffusion coefficient, according to which we choose the suitable regenerator materials, will prove to be a useful reference. We will also discuss the impact of resistance of sphere regenerator materials on the performance of the refrigerator and the method to improve it. Take an overall consideration, suitable-size Er3Ni will be applied as the regenerator materials at the cold head and we achieve a remarkable 14.7 K no-load temperature.

  19. A Study of the Effects of Material Type and Configuration on Optical Cross Section

    Science.gov (United States)

    2012-09-01

    different material configurations using different combinations of diffuse and specular materials in the bistatic illumination con- dition. OCS was...different material configurations using different combinations of diffuse and specular materials in the bistatic illumination condition. OCS was...LIMITATION OF ABSTRACT Same as Report ( SAR ) 18. NUMBER OF PAGES 8 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b. ABSTRACT unclassified c

  20. Molecular epidemiology of Staphylococcus aureus bacteremia in a single large Minnesota medical center in 2015 as assessed using MLST, core genome MLST and spa typing.

    Science.gov (United States)

    Park, Kyung-Hwa; Greenwood-Quaintance, Kerryl E; Uhl, James R; Cunningham, Scott A; Chia, Nicholas; Jeraldo, Patricio R; Sampathkumar, Priya; Nelson, Heidi; Patel, Robin

    2017-01-01

    Staphylococcus aureus is a leading cause of bacteremia in hospitalized patients. Whether or not S. aureus bacteremia (SAB) is associated with clonality, implicating potential nosocomial transmission, has not, however, been investigated. Herein, we examined the epidemiology of SAB using whole genome sequencing (WGS). 152 SAB isolates collected over the course of 2015 at a single large Minnesota medical center were studied. Staphylococcus protein A (spa) typing was performed by PCR/Sanger sequencing; multilocus sequence typing (MLST) and core genome MLST (cgMLST) were determined by WGS. Forty-eight isolates (32%) were methicillin-resistant S. aureus (MRSA). The isolates encompassed 66 spa types, clustered into 11 spa clonal complexes (CCs) and 10 singleton types. 88% of 48 MRSA isolates belonged to spa CC-002 or -008. Methicillin-susceptible S. aureus (MSSA) isolates were more genotypically diverse, with 61% distributed across four spa CCs (CC-002, CC-012, CC-008 and CC-084). By MLST, there was 31 sequence types (STs), including 18 divided into 6 CCs and 13 singleton STs. Amongst MSSA isolates, the common MLST clones were CC5 (23%), CC30 (19%), CC8 (15%) and CC15 (11%). Common MRSA clones were CC5 (67%) and CC8 (25%); there were no MRSA isolates in CC45 or CC30. By cgMLST analysis, there were 9 allelic differences between two isolates, with the remaining 150 isolates differing from each other by over 40 alleles. The two isolates were retroactively epidemiologically linked by medical record review. Overall, cgMLST analysis resulted in higher resolution epidemiological typing than did multilocus sequence or spa typing.

  1. Dopant type and/or concentration selective dry photochemical etching of semiconductor materials

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, C.I.H.; Dishman, J.L.

    1987-03-10

    A method is described of selectively photochemically dry etching a first semiconductor material of a given composition in the presence of a second semiconductor material which is of a composition different from the first material. The second material is not substantially etched during the method which comprises: subjecting both materials to the same photon flux of an energy greater than their respective direct bandgaps and to the same gaseous chemical etchant under conditions where the etchant would be ineffective for chemical etching of either material where the photons not present, the conditions also being such that the resultant electronic structure of the first semiconductor material under the photon flux is sufficient for the first material to undergo substantial photochemical etching under the conditions. The conditions also are such that the resultant electronic structure of the second semiconductor material under the photon flux is not sufficient for the second material to undergo substantial photochemical etching under the conditions.

  2. Reports of the 8th new type nuclear fuel materials studying meeting. Present status of the plutonium mixed oxide fuel application

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-01

    This was the reports of the 8th New Type Nuclear Fuel Materials Studying Meeting, as a circle of Yayoi Studying Group meeting held on March 17, 1997. This meeting was added to a subtitle of `Present status and problems of plutonium mixed oxide application`, which had 12 lectures. In this meeting, for the MOX fuels putting the most attention in the field of nuclear fuel development at present, many specialists introduced faithfully on present status and problems of its nuclear features, reactor core design, and application to light water reactor and fast reactor. And, following reports were executed: (A) On feature of plutonium and reactor core design; (1) nuclear feature of plutonium, (2) nuclear design of BWR, (3) nuclear design of PWR, (4) nuclear design of FBR, and (5) and (6) properties of the MOX fuel; (B) On application of plutonium to the light water reactor; (1) preparation of the MOX fuel for light water reactor, (2) radiation behavior and using result of the MOX fuel for BWR, and (3) radiation behavior and using result of the MOX fuel for PWR; and (C) On application of plutonium to the fast reactor; (1) fuel preparation, (2) radiation behavior, and (3) reprocessing of the fast reactor fuel. (G.K.)

  3. Pseudomembranous colitis on aytopsy materials of large multi-type hospital

    Directory of Open Access Journals (Sweden)

    E. I. Belinskaya

    2014-01-01

    Full Text Available As a result of wide and irrational antibiotics using the problem of AAC has become an issue. According to medical sources Clostridium difficile-associated diarrhea (pseudomembranous colitis is not registered and its clinical diagnostics is unsatisfactory.The purpose of the research is to study the pseudomembranouscolitis incidence on autopsy material in a multi-type hospital and to give its clinical and morphological characteristics.Methods and materials: the medical records (autopsy protocols, patients’ histories of the deceased with pseudomembranous colitis diagnosed on autopsy for the period of 2008–2013 yy were analyzed. The macroscopic changes of small and large bowel (size and pseudomembrane location, lesion focus, other colonic wall variations were assessed on autopsy. The stainings by hematoxylin-eozin, azur, PAS-reaction were used for histological diagnostics. The bacteriological testing was conducted in 2 cases.The results. The growing tendency of the pseudomembranous colitis frequency as well as its parts in the autopsy structures were revealed. Six cases of pseudomembranous colitis are detected on autopsy (0,28% of all performed autopsies in Irkutsk hospital №1 for 2008–2010 y.y. Twenty cases of pseudomembranous colitis were registered for 2011–2013 y.y., that was 1,52% in the autopsy structure. The risk factors of pseudomembranous colitis development, its clinical and morphological presentations were identified. Low lifetime diagnostics of this disease was remarked and its causes were analyzed.Conclusion. The problem of antibiotic-associated diarrhea with pseudomembranous colitis development is an issue because of the growing incidence of this disease and its unsatisfactory clinical diagnostics.

  4. Amino acid adsorption on mesoporous materials: influence of types of amino acids, modification of mesoporous materials, and solution conditions.

    Science.gov (United States)

    Gao, Qiang; Xu, Wujun; Xu, Yao; Wu, Dong; Sun, Yuhan; Deng, Feng; Shen, Wanling

    2008-02-21

    In order to disclose the dominant interfacial interaction between amino acids and ordered mesoporous materials, the adsorption behaviors of five amino acids on four mesoporous materials were investigated in aqueous solutions with adjustable amino acid concentration, ion strength, and pH. The selected amino acids were acidic amino acid glutamic acid (Glu), basic amino acid arginine (Arg), and neutral amino acids phenylalanine (Phe), leucine (Leu), and alanine (Ala), and the selected mesoporous materials were SBA-15, Al-SBA-15, CH3(10%)-SBA-15, and CH3(20%)-SBA-15. The adsorption capacities of Glu and Arg were strongly dependent on pH and surface charge of the mesoporous adsorbent. The adsorption of Phe showed pH insensitivity but depended on the surface organic functionalization of mesoporous adsorbent. On the basis of the theoretical analysis about the interaction between amino acid and adsorbent, such a remarkable difference was attributed to the different nature of the interaction between amino acid and adsorbent. Arg could be readily adsorbed on the surface of SBA-15, especially Al-SBA-15, under appropriate pH in which the electrostatic interaction was predominant. The driving force of Phe adsorption on mesoporous adsorbent mainly came from the hydrophobic interaction. Therefore, the adsorption capability of Arg decreased with increasing ion strength of solution, while the adsorption capability of Phe increased with the increasing degree of CH3 functionalization on SBA-15. For neutral amino acid Phe, Ala, and Leu, the adsorption capability increased with the increase of the length of their side chains, which was another evidence of hydrophobic effect. Thus, all the adsorption of amino acids on mesoporous silica materials can be decided by the combined influence of two fundamental interactions: electrostatic attraction and hydrophobic effect.

  5. Analysis of Variations in White-Belly and White-Core Rice Kernels Within a Panicle and the Effect of Panicle Type

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin-cheng; Md A.Alim; LIN Zhao-miao; LIU Zheng-hui; LI Gang-hua; WANG Qiang-sheng; WANG Shao-hua; DING Yan-feng

    2014-01-01

    This study aims to investigate the variation in occurrence of white-belly rice kernel (WBRK) and white-core rice kernel (WCRK) among different positions within a panicle. Twenty-four M4 mutants involved in four panicle types, namely the compact, intermediate, loose, and chicken foot panicle were used. They derived from a japonica rice cultivar Wuyujing 3. Considerable differences in morphological characters existed among the four types of panicle, especially in panicle length, the secondary branch number and ratio of grain number to total branch length. Marked differences were found in WBRK and WCRK among different positions within a panicle for all types of panicle. In general, grains located on the primary rachis and top rachis branches had higher WBRK and WCRK percentage than those on the secondary rachis and bottom rachis branches. WCRK exhibited larger variation among grain positions than WBRK did. Moreover, there was a significant difference in WCRK/WBRK among grain positions within a panicle, with primary rachis and top rachis branches having higher values than the secondary and bottom rachis. In addition, panicle type showed no significant effect on the pattern of WBRK and WCRK occurrence within a panicle. The results indicated the difference in mechanism of WBRK and WCRK formation in grain position within a panicle, and are valuable for breeding and agronomic practices aimed at lowering chalky grain rate.

  6. Wear mechanism of disc-brake block material for new type of drilling rig

    Institute of Scientific and Technical Information of China (English)

    Xinhua WANG; Simin WANG; Siwei ZHANG; Deguo WANG

    2008-01-01

    To improve friction and wear performance and service life of the disc-brake pair material of a drilling rig, a new type of asbestos-free frictional material with better performance for disc-brake blocks is developed, and its wear mechanism is investigated by friction and wear experiments. Topography and ele-mentary components of the brake block's wear surface are analyzed by employing SEM and EDAX patterns, revealing its tribological behaviour and wear mechan-ism. When the frictional temperature is lower, the surface film of the brake block is thinner, dense, smooth with plasticity, and divided into the mixture area, Fe-abundant area, carbon-abundant area and spalling area. The mixture area consists of various constituents of frictional pairs without ploughing and rolling trace. The Fe-abundant area mainly consists of iron and other constituents. The carbon-abundant area is the zone where graphite and organic fibre are comparatively gathered, while the spalling area is the zone where the surface film is spalled and its surface is rough and uneven, with a loose and denuded state. During the period of high frictional temperature, the frictional surface is also divided into the mixture area, Fe-abundant area and spalling area. In this case, the mixture area consists of abrasive dust from friction pairs, and the surface film is distributed with crumby hard granules, exiguous oxide, carbide granules and sheared slender fibre. The Fe-abundant area is mostly an oxide layer of iron with a flaky distribution. Fracture and spalling traces as well as an overlapping structure of multilayer surface films can be easily found on the surface film. The components of the spalling area are basically the same as that of the matrix. At the beginning of wear, the hard peaks from the friction surface of the disc-brake plough on the surface of the brake block. With increasing frictional temperature, the friction surface begins to soften and expand, and oxidized wear occurs at the same

  7. Synthesis of Core/Shell Type CdS/TiO2%核壳结构CdS/TiO2的制备与表征

    Institute of Scientific and Technical Information of China (English)

    王智宇; 陈景鑫; 张福安; 钱国栋; 樊先平

    2008-01-01

    This paper introduced a two-step method for the synthesis of core/shell type nano-composites,which exhibited superior properties over single material,like photoactivity.The core material,cadium sulfide were prepared via a hydrothermal method,using PVP as surfactant to avoid severe aggregation.We obtained high crystalline nanocrystals with dimensions varied from 10 nm to 12 nm,and the nano-particles cohered together to form clusters.We applied a sonochemical route to improve the dispersion properties during the process of hydrolysation of Ti(OC4H9)4 which coated core material with a layer of stable TiO2.By adjusting molar ratio of precursors,morphopology of CdS/TiO2 transferred from CdS embedded in continuous TiO2 matrix to products with obvious core/shell structure,which validated the unique effects of sonochemical method in the synthesis of nano-materials.And from the absorbance spectra of degraded methyl orange,the nanocomposites showed superior photoactivity over single material due to better separation of opposite carriers.%通过水热法合成分散性良好的CdS纳米颗粒,并采用声化学法在颗粒外包覆TiO2壳层,获得的复合材料具有更好的光催化特性.讨论了水热反应温度保温时间与晶粒尺寸、结晶性之间的关系以及声化学制备过程中反应条件与陈化时间对壳层生长的影响.采用X射线衍射、透射电镜、漫反射光谱、光催化性能测试等手段表征CdS颗粒的尺寸、形貌及CdS/TiO2的结构与光催化特性.结果表明:水热过程中,提高反应温度、保温时间有利于提高产物的结晶性.声化学合成CdS/TiO2复合材料过程中,超声作用能促进核壳结构的形成.提高前驱溶液的浓度,在获得CdS/TiO2核壳结构的同时会析出TiO2纳米粒子.在降解甲基橙的实验中,CdS/TiO2材料表现出比单组分材料更好的催化性能.

  8. Nanocrystals magnetic contribution to FINEMET-type soft magnetic materials with Ge addition

    Energy Technology Data Exchange (ETDEWEB)

    Muraca, D. [Lab. de Solidos Amorfos, Facultad de Ingenieria-INTECIN, UBA-CONICET, Paseo Colon 850, C1063ACV Buenos Aires (Argentina)], E-mail: diego.muraca@gmail.com; Silveyra, J.; Pagnola, M. [Lab. de Solidos Amorfos, Facultad de Ingenieria-INTECIN, UBA-CONICET, Paseo Colon 850, C1063ACV Buenos Aires (Argentina); Cremaschi, V. [Lab. de Solidos Amorfos, Facultad de Ingenieria-INTECIN, UBA-CONICET, Paseo Colon 850, C1063ACV Buenos Aires (Argentina)

    2009-11-15

    Over the last years several works have been published in which magnetic and structural properties of soft magnetic nanocrystalline alloys were reported. Among these, there are a series of articles where the nanocrystals composition of FINEMET-type alloys with Ge addition was obtained by Moessbauer spectroscopy (MS) and X-ray diffraction (XRD). By considering a linear relationship between the magnetic moments of the nanocrystals and the composition of various elements in these crystallites, the magnetic moment of the nanocrystals was calculated. This paper reviews results obtained by different authors since 1980 and they are compared with ours. In turn, we revised some elements not previously considered for the calculus of the nanocrystals composition that allowed us to obtain the magnetic moment of the crystallites in the alloy. In particular, we analyzed FINEMET-type alloys with replacement of B for Ge: Fe{sub 73.5}Si{sub 13.5}Ge{sub 2}B{sub 7}Nb{sub 3}Cu{sub 1} and Fe{sub 73.5}Si{sub 13.5}Ge{sub 4}B{sub 5}Nb{sub 3}Cu{sub 1}. The nanocrystalline structure was obtained by isothermal annealing of melt-spun ribbons at 823 K for 1 h. From MS and XRD we obtained the atomic composition of the nanocrystals in the magnetic material. The magnetic contribution of the nanocrystals to the alloy was calculated using a linear model and the results were compared with experimental measurements of the samples.

  9. Endovascular Repair for Type A Aortic Dissection After Transcatheter Aortic Valve Replacement With a Medtronic CoreValve.

    Science.gov (United States)

    Berfield, Kathleen K S; Sweet, Matthew P; McCabe, James M; Reisman, Mark; Mackensen, G Burkhard; Mokadam, Nahush A; Dean, Larry S; Smith, Jason W

    2015-10-01

    Transcatheter aortic valve replacement is being used with increasing frequency in patients with severe aortic stenosis who are otherwise deemed to be at high surgical risk. Aortic dissection is a rare complication of transcatheter aortic valve replacement and poses a unique management dilemma. We describe the treatment of an acute Stanford type A aortic dissection after transcatheter aortic valve replacement with a modified thoracic endovascular stent graft in a 95-year-old woman. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  10. Novel amide-type ligand bearing bis-pyridine cores: Synthesis, spectral characterizations and X-ray structure analyses

    Science.gov (United States)

    Ke, Shaoyong

    2016-08-01

    The novel salicylamide-type ligand containing bis-pyridine moieties, i.e. 2-((6-chloropyridin-3-yl)methoxy)-N-(2-((6-chloropyridin-3-yl)methylthio)phenyl)benzamide, which has been successfully synthesized and characterized by typical spectroscopic techniques mainly including IR, 1H NMR and ESI-MS. The structure of target compound was further determined by single crystal X-ray diffraction method and which crystallized in the monoclinic system with space group P2(1)/c.

  11. Development of Integrated Natural Science Teaching Materials Webbed Type with Applying Discourse Analysis on Students Grade VIII in Physics Class

    Science.gov (United States)

    Sukariasih, Luh

    2017-05-01

    This study aims to produce teaching materials integrated natural science (IPA) webbed type of handout types are eligible for use in integrated science teaching. This type of research IS a kind of research and development / Research and Development (R & D) with reference to the 4D development model that is (define, design, develop, and disseminate). Data analysis techniques used to process data from the results of the assessment by the validator expert, and the results of the assessment by teachers and learners while testing is limited (12 students of class VIII SMPN 10 Kendari) using quantitative descriptive data analysis techniques disclosed in the distribution of scores on the scale of five categories grading scale that has been determined. The results of due diligence material gain votes validator material in the category of “very good” and “good”, of the data generated in the feasibility test presentation obtained the category of “good” and “excellent”, from the data generated in the feasibility of graphic test obtained the category of “very good “and” good “, as well as of the data generated in the test the feasibility of using words and language obtained the category of“very good “and” good “, so with qualifications gained the teaching materials IPA integrated type webbed by applying discourse analysis on the theme of energy and food for Junior High School (SMP) grade VIII suitable as teaching materials. In limited testing, data generated in response to a science teacher at SMPN 10 Kendari to product instructional materials as “excellent”, and from the data generated while testing is limited by the 12 students of class VIII SMPN 10 Kendari are more students who score indicates category “very good”, so that the qualification obtained by the natural science (IPA) teaching material integrated type webbed by applying discourse analysis on the theme of energy and food for SMP / class VIII fit for use as teaching material.

  12. Ice Core Investigations

    Science.gov (United States)

    Krim, Jessica; Brody, Michael

    2008-01-01

    What can glaciers tell us about volcanoes and atmospheric conditions? How does this information relate to our understanding of climate change? Ice Core Investigations is an original and innovative activity that explores these types of questions. It brings together popular science issues such as research, climate change, ice core drilling, and air…

  13. Ice Core Investigations

    Science.gov (United States)

    Krim, Jessica; Brody, Michael

    2008-01-01

    What can glaciers tell us about volcanoes and atmospheric conditions? How does this information relate to our understanding of climate change? Ice Core Investigations is an original and innovative activity that explores these types of questions. It brings together popular science issues such as research, climate change, ice core drilling, and air…

  14. Relationship between nursing students' preference for types of teaching materials and learning effects of self-learning tool.

    Science.gov (United States)

    Kitajima, Yasuko; Yamashita, Masako; Nakamura, Mitsuhiro; Maeda, Jukai; Aida, Kyouko; Kanai-Pak, Masako; Huang, Zhifeng; Nagata, Ayanori; Ogata, Taiki; Kuwahara, Noriaki; Ota, Jun

    2014-01-01

    The purpose of this study was to investigate the relationship between learning effects of the self-learning tool for nursing students and types of teaching materials. Ten nursing students were asked to perform transfer a patient from bed to wheelchair after watching the demo video and practicing 20 minutes. The students' performance was evaluated before and after practicing. The students were also asked to choose teaching materials that would be developed in the future. Out of nine teaching materials, the students chose seven of them. Correspondence analysis was conducted between the results of the evaluation of students' transfer technique and their preference of teaching materials. The results indicated that there was no relationship between the preference of teaching materials and the scores of transfer techniques. The authors concluded that the self-learning was not affected by the preference of teaching materials.

  15. Evaluation of the effect of 4 types of knots on the mechanical properties of 4 types of suture material used in small animal practice.

    Science.gov (United States)

    Avoine, Xytilis; Lussier, Bertrand; Brailovski, Vladimir; Inaekyan, Karine; Beauchamp, Guy

    2016-04-01

    The influence of the type of material used, knot configuration, and use of an additional throw on the tensile force at failure, the elongation, and the mode of failure of different configurations of linear sutures and knotted suture loops was evaluated in this in-vitro mechanical study. We hypothesized that all types of knots would significantly influence the initial force and elongation of suture materials and would influence the force and elongation at which the knotted loops break, but not their mode of failure. A total of 432 samples of 4 types of size 3-0 suture material (polydioxanone, polyglecaprone 25, polyglactin 910, and nylon), representing 9 configurations, were tested in a tensiometer. The configurations were 1 linear suture without a knot and the following loops: square (SQ) knot; surgeon's (SU) knot; granny (GR) knot; and sliding half-hitch (SHH) knot using either 4 and 5 or 3 and 4 throws, depending on the material. For polydioxanone, SQ and SU knots did not decrease the initial force at failure of the suture. Granny (GR) and SHH knots decreased the tensile force at failure and elongation by premature failure of the loop. For polyglecaprone 25, all knots decreased the initial force at failure of the suture, with SHH being weaker than the other knots. For coated polyglactin 910, all knots decreased the initial force at failure of the suture and slippage increased significantly compared with the other 3 sutures. The use of SQ knots with 3 throws did not result in a safe knot. For nylon, knots did not alter the original mechanics of the suture. In conclusion, all knots and types of suture material do not necessarily have the same effect on the initial tensile force at failure of suture materials.

  16. Effects of radiation types and dose rates on selected cable-insulating materials

    Science.gov (United States)

    Hanisch, F.; Maier, P.; Okada, S.; Schönbacher, H.

    A series of radiation tests have been carried out on halogen-free cable-insulating and cable-sheathing materials comprising commercial LDPE, EPR, EVA and SIR compounds. samples were irradiated at five different radiation sources, e.g. a nuclear reactor, fuel elements, a 60Co source, and in the stray radiation field of high-energy proton and electron accelerators at CERN and DESY. The integrated doses were within 50-5000 kGy and the dose rates within 10 mGy/s-70 Gy/s. Tensile tests and gel-fraction measurements were carried out. The results confirm that LDPEs are very sensitive to long-term ageing effects, and that important errors exceeding an order of magnitude can be made when assessing radiation damage by accelerated tests. On the other hand, well-stabilized LDPEs and the cross-linked rubber compounds do not show large dose-rate effects for the values given above. Furthermore, the interpretation of the elongation-at-break data and their relation to gel-fraction measurements show that radiation damage is related to the total absorbed dose irrespective of the different radiation types used in this experiment.

  17. The Growth of Aspergillus Niger on a Wood Based Material with 4 Types of Wall Finishing

    Directory of Open Access Journals (Sweden)

    Subramaniam Menega

    2016-01-01

    Full Text Available Buildings are a vital component in a human’s daily life. It provides shelter from the environment, weather and animals. Mold growth within the building might be caused by the moisture problems which directly act on it such as water leaks or indirect factor such as high humidity levels. This growth causes esthetic problems and deterioration of its wall coatings. Spores from the fungi also cause health problems to humans. The fungus species studied in this research is Aspergillus niger. The material is made of wood and its finishing is thick wallpaper, thin wallpaper, acrylic paint and glycerol based paint. ASTMD5590-00 standard was used to evaluate fungal growth and to determine if non antifungal agent was effective in inhibiting the amount of fungal growth on four types of wall finishing used on wooden walls. This research was conducted without using any antifungal agent. Highest percentage of growth of the fungi was found on acrylic paint, followed by glycerol based paint and thin wallpaper. Thick wall paper shows the least growth of fungi. The maximum growth is visible on day 12 which is more than 60% by all the wall finishing.

  18. Dispersion characteristics of THz surface plasmons in nonlinear graphene-based parallel-plate waveguide with Kerr-type core dielectric

    Science.gov (United States)

    Yarmoghaddam, Elahe; Rakheja, Shaloo

    2017-08-01

    We theoretically model the dispersion characteristics of surface plasmons in a graphene-based parallel-plate waveguide geometry using nonlinear Kerr-type core (inter-plate) dielectric. The optical nonlinearity of graphene in the terahertz band under high light intensity is specifically included in the analysis. By solving Maxwell's equations and applying appropriate boundary conditions, we show that the waveguide supports four guided plasmon modes, each of which can be categorized as either symmetric or anti-symmetric based on the electric field distribution in the structure. Of the four guided modes, two modes are similar in characteristics to the modes obtained in the structure with linear graphene coating, while the two new modes have distinct characteristics as a result of the nonlinearity of graphene. We note that the group velocity of one of the plasmon modes acquires a negative value under high light intensity. Additionally, the optical nonlinearity of the core dielectric leads to a significant enhancement in the localization length of various plasmon modes. The description of the intra-band optical conductivity of graphene incorporates effects of carrier scatterings due to charged impurities, resonant scatterers, and acoustic phonons at 300 K. The proposed structure offers flexibility to tune the waveguide characteristics and the mode index by changing light intensity and electrochemical potential in graphene for reconfigurable plasmonic devices.

  19. Synthesis of a Novel Core-shell Type Acrylic-polyurethane Hybrid Emulsion Containing Siloxane and Fluorine as well as Water and the Oil Resistances of Cured Film

    Institute of Scientific and Technical Information of China (English)

    Jing CHAO; Xing Yuan ZHANG; Jia Bing DAI; Zhen GE; Lin Lin FENG

    2006-01-01

    Siliconated polyurethane (Si-PU) was synthesized using isophorone diisocyanate (IPDI), hydroxybutyl-terminated polydimethylsiloxane (PDMS), polytetramethylene ether glycol (PTMG), polypropylene glycol (PPG), 1,6-hexanediol (HDO), dimethylol propionic acid (DMPA) and triethylamine (TEA). Based on butyl acrylate (BA), 2, 2, 2-trifluoroethylmethacrylate (TFEMA) and Si-PU as a seed emulsion, a novel core-shell type acrylic-polyurethane hybrid emulsion, containing siloxane and fluorine (F-Si-PU), was prepared by seeded emulsion polymerization. The contents of siloxane and fluorine were determined according to the feed ratio. Fourier transform infrared spectroscopy (FTIR) was used to identify the chain structures of Si-PU and F-Si-PU. Investigation of transmission electron microscopy (TEM) confirmed the core-shell structure of F-Si-PU emulsion. Measurement results of water contact angle and the swelling ratio in water and n-octane for cured film showed that the water and the oil resistances for F-Si-PU had been significantly improved at a suitable content of fluorine and siloxane.

  20. Personal attributes that influence the adequate management of hypertension and dyslipidemia in patients with type 2 diabetes. Results from the DIAB-CORE Cooperation

    Directory of Open Access Journals (Sweden)

    Rückert Ina-Maria

    2012-10-01

    Full Text Available Abstract Background Hypertension and dyslipidemia are often insufficiently controlled in persons with type 2 diabetes (T2D in Germany. In the current study we evaluated individual characteristics that are assumed to influence the adequate treatment and control of hypertension and dyslipidemia and aimed to identify the patient group with the most urgent need for improved health care. Methods The analysis was based on the DIAB-CORE project in which cross-sectional data from five regional population-based studies and one nationwide German study, conducted between 1997 and 2006, were pooled. We compared the frequencies of socio-economic and lifestyle factors along with comorbidities in hypertensive participants with or without the blood pressure target of  Results We included 1287 participants with T2D of whom n = 1048 had hypertension and n = 636 had dyslipidemia. Uncontrolled blood pressure was associated with male sex, low body mass index (BMI, no history of myocardial infarction (MI and study site. Uncontrolled blood lipid levels were associated with male sex, no history of MI and study site. The odds of receiving no pharmacotherapy for hypertension were significantly greater in men, younger participants, those with BMI  Conclusion In the DIAB-CORE study, the patient group with the greatest odds of uncontrolled co-morbidities and no pharmacotherapy was more likely comprised of younger men with low BMI and no history of cardiovascular disease.