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Sample records for feptb nano-composite hard

  1. Progress in Tribological Properties of Nano-Composite Hard Coatings under Water Lubrication

    Directory of Open Access Journals (Sweden)

    Qianzhi Wang

    2017-02-01

    Full Text Available The tribological properties, under water-lubricated conditions, of three major nano-composite coatings, i.e., diamond-like carbon (DLC or a-C, amorphous carbon nitride (a-CNx and transition metallic nitride-based (TiN-based, CrN-based, coatings are reviewed. The influences of microstructure (composition and architecture and test conditions (counterparts and friction parameters on their friction and wear behavior under water lubrication are systematically elucidated. In general, DLC and a-CNx coatings exhibit superior tribological performance under water lubrication due to the formation of the hydrophilic group and the lubricating layer with low shear strength, respectively. In contrast, TiN-based and CrN-based coatings present relatively poor tribological performance in pure water, but are expected to present promising applications in sea water because of their good corrosion resistance. No matter what kind of coatings, an appropriate selection of counterpart materials would make their water-lubricated tribological properties more prominent. Currently, Si-based materials are deemed as beneficial counterparts under water lubrication due to the formation of silica gel originating from the hydration of Si. In the meantime, the tribological properties of nano-composite coatings in water could be enhanced at appropriate normal load and sliding velocity due to mixed or hydrodynamic lubrication. At the end of this article, the main research that is now being developed concerning the development of nano-composite coatings under water lubrication is described synthetically.

  2. Nano-composite materials

    Science.gov (United States)

    Lee, Se-Hee; Tracy, C. Edwin; Pitts, J. Roland

    2010-05-25

    Nano-composite materials are disclosed. An exemplary method of producing a nano-composite material may comprise co-sputtering a transition metal and a refractory metal in a reactive atmosphere. The method may also comprise co-depositing a transition metal and a refractory metal composite structure on a substrate. The method may further comprise thermally annealing the deposited transition metal and refractory metal composite structure in a reactive atmosphere.

  3. Magnetic properties of nanocrystallized Fe-Pt-B melt-spun ribbons

    International Nuclear Information System (INIS)

    Yamamoto, Tokujiro; Omori, Akihiro; Kimura, Hisamichi; Inoue, Akihisa

    2007-01-01

    L1 0 FePt nanoparticles have been prepared by etching grain boundaries of heat-treated melt-spun Fe-19Pt-25B (at.%) alloy ribbons. It is revealed that an L1 0 FePt nanocrystalline phase is directly formed from the Fe-Pt-B amorphous ribbons by long-time heat treatment at low temperatures in the vicinity of 723 K. With increasing heat treatment time, dimensions of the nanocrystallized FePt grains increase, accompanied by a change from soft ferromagnetic to hard ferromagnetic. The ribbon crystallized at 723 K for 1.8 ks consists of only an FePt L1 0 phase and its coercivity is as low as 0.381 kA/m. However, it increases to 372 kA/m with increasing grain size of precipitated L1 0 phase to about 30 nm by heat treatment for 86.4 ks, while the saturation magnetic flux density remains constant at about 0.4 T. Etching boundaries in heat-treated ribbons has been performed to obtain ferromagnetic L1 0 FePt nanoparticles and several particles were observed by means of transmission electron microscopy

  4. Comparison between properties of polyurethane nano composites prepared by two different methods

    International Nuclear Information System (INIS)

    Barmar, M.; Barikani, M.; Fereidoonnia, M.

    2009-01-01

    In this work, a thermoplastic polyurethane elastomer model based on polytetramethylene glycol. toluene diisocyanate and 1,4-butanediol was selected and synthesized. According to this model two types of polyurethane nano composites were prepared by in situ polymerization and melt intercalation procedures. The organo-modified nano clay was used in nano composites samples in 0.4 weight percent level. The prepared nano composites were studied by WAXD, tensile and thermal analysis. Thermal properties of the nano composites were higher than those of pure polyurethane elastomers. Nano composites prepared via melt intercalation method showed a lower tensile strength and hardness than those prepared through in situ polymerization method

  5. Poly (lactic acid organoclay nano composites for paper coating applications

    Directory of Open Access Journals (Sweden)

    Tatcha Sonjui

    2014-10-01

    Full Text Available Poly(lactic acid or PLA is a well-known biodegradable polymer derived from renewable resources such as corn strach, tapioca strach, and sugar cane. PLA is the most extensively utilized biodegradable polyester with potential to replace conventional petrochemical-based polymers. However, PLA has some drawbacks, such as brittleness and poor gas barrier properties. Nano composite polymers have experience and increasing interest due to their characteristics, especially in mechanical and thermal properties. The objectives of this research were to prepare PLA formulations using three different PLAs. The formulas giving high gloss coating film were selected to prepare nano composite film by incorporated with different amount of various types of organoclays. The physical properties of the PLA coating films were studied and it was found that the PLA 7000D with 0.1%w/w of Cloisite 30B provided decent viscosity for coating process. In addition, the nano composite coating films showed good physical properties such as high gloss, good adhesion, and good hardness. There is a possibility of using the obtained formulation as a paper coating film.

  6. High performance nano-composite technology development

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Whung Whoe; Rhee, C. K.; Kim, S. J.; Park, S. D. [KAERI, Taejon (Korea, Republic of); Kim, E. K.; Jung, S. Y.; Ryu, H. J. [KRICT, Taejon (Korea, Republic of); Hwang, S. S.; Kim, J. K.; Hong, S. M. [KIST, Taejon (Korea, Republic of); Chea, Y. B. [KIGAM, Taejon (Korea, Republic of); Choi, C. H.; Kim, S. D. [ATS, Taejon (Korea, Republic of); Cho, B. G.; Lee, S. H. [HGREC, Taejon (Korea, Republic of)

    1999-06-15

    The trend of new material development are being to carried out not only high performance but also environmental attraction. Especially nano composite material which enhances the functional properties of components, extending the component life resulting to reduced the wastes and environmental contamination, has a great effect on various industrial area. The application of nano composite, depends on the polymer matrix and filler materials, has various application from semiconductor to medical field. In spite of nano composite merits, nano composite study are confined to a few special materials as a lab, scale because a few technical difficulties are still on hold. Therefore, the purpose of this study establishes the systematical planning to carried out the next generation projects on order to compete with other countries and overcome the protective policy of advanced countries with grasping over sea's development trends and our present status. (author).

  7. High performance nano-composite technology development

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Whung Whoe; Rhee, C. K.; Kim, S. J.; Park, S. D. [KAERI, Taejon (Korea, Republic of); Kim, E. K.; Jung, S. Y.; Ryu, H. J. [KRICT, Taejon (Korea, Republic of); Hwang, S. S.; Kim, J. K.; Hong, S. M. [KIST, Taejon (Korea, Republic of); Chea, Y. B. [KIGAM, Taejon (Korea, Republic of); Choi, C. H.; Kim, S. D. [ATS, Taejon (Korea, Republic of); Cho, B. G.; Lee, S. H. [HGREC, Taejon (Korea, Republic of)

    1999-06-15

    The trend of new material development are being to carried out not only high performance but also environmental attraction. Especially nano composite material which enhances the functional properties of components, extending the component life resulting to reduced the wastes and environmental contamination, has a great effect on various industrial area. The application of nano composite, depends on the polymer matrix and filler materials, has various application from semiconductor to medical field. In spite of nano composite merits, nano composite study are confined to a few special materials as a lab, scale because a few technical difficulties are still on hold. Therefore, the purpose of this study establishes the systematical planning to carried out the next generation projects on order to compete with other countries and overcome the protective policy of advanced countries with grasping over sea's development trends and our present status. (author).

  8. High performance nano-composite technology development

    International Nuclear Information System (INIS)

    Kim, Whung Whoe; Rhee, C. K.; Kim, S. J.; Park, S. D.; Kim, E. K.; Jung, S. Y.; Ryu, H. J.; Hwang, S. S.; Kim, J. K.; Hong, S. M.; Chea, Y. B.; Choi, C. H.; Kim, S. D.; Cho, B. G.; Lee, S. H.

    1999-06-01

    The trend of new material development are being to carried out not only high performance but also environmental attraction. Especially nano composite material which enhances the functional properties of components, extending the component life resulting to reduced the wastes and environmental contamination, has a great effect on various industrial area. The application of nano composite, depends on the polymer matrix and filler materials, has various application from semiconductor to medical field. In spite of nano composite merits, nano composite study are confined to a few special materials as a lab, scale because a few technical difficulties are still on hold. Therefore, the purpose of this study establishes the systematical planning to carried out the next generation projects on order to compete with other countries and overcome the protective policy of advanced countries with grasping over sea's development trends and our present status. (author).

  9. Synthesis and magnetic properties of hard magnetic (CoFe{sub 2}O{sub 4})-soft magnetic (Fe{sub 3}O{sub 4}) nano-composite ceramics by SPS technology

    Energy Technology Data Exchange (ETDEWEB)

    Fei Chunlong [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China); Zhang Yue [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China); Key Laboratory for the Green Preparation and Application of Functional Materials of Ministry of Education, Hubei University, Wuhan 430062 (China); Yang Zhi; Liu Yong [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China); Xiong Rui, E-mail: wudawujiron@163.co [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China) and Key Laboratory for the Green Preparation and Application of Functional Materials of Ministry of Education, Hubei University, Wuhan 430062 (China); Shi Jing [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China); International Center for Materials Physics, Shen Yang 110015 (China); Ruan Xuefeng [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials, Wuhan University, Wuhan 430072 (China)

    2011-07-15

    CoFe{sub 2}O{sub 4}/Fe{sub 3}O{sub 4} nano-composite ceramics were synthesized by Spark Plasma Sintering. The X-ray diffraction patterns show that all samples are composed of CoFe{sub 2}O{sub 4} and Fe{sub 3}O{sub 4} phases when the sintering temperature is below 900 {sup o}C. It is found that the magnetic properties strongly depend on the sintering temperature. The two-step hysteresis loops for samples sintered below 500 {sup o}C are observed, but when sintering temperature reaches 500 {sup o}C, the step disappears, which indicates that the CoFe{sub 2}O{sub 4} and Fe{sub 3}O{sub 4} are well exchange coupled. As the sintering temperature increases from 500 to 800 {sup o}C, the results of X-ray diffractometer indicate the constriction of crystalline regions due to the ion diffusion at the interfaces of CoFe{sub 2}O{sub 4}/Fe{sub 3}O{sub 4} phases, which have great impact on the magnetic properties. - Research highlights: In this work, a series of CoFe{sub 2}O{sub 4}/Fe{sub 3}O{sub 4} nano-composite ceramics were prepared through SPS. The magnetic properties of these ceramics have been studied in detail. It is found that the magnetic properties strongly depend on the sintering temperature.

  10. Polymer/Layered Silicate Nano composites

    International Nuclear Information System (INIS)

    Bakhit, M.E.E.H.

    2012-01-01

    Polymer–clay nano composites have attracted the attention of many researchers and experimental results are presented in a large number of recent papers and patents because of the outstanding mechanical properties and low gas permeabilities that are achieved in many cases. Polymer-clay nano composites are a new class of mineral-field polymer that contain relatively small amounts (<10%) of nanometer-sized clay particles. Polymer/clay nano composites have their origin in the pioneering research conducted at Toyota Central Research Laboratories and the first historical record goes back to 1987. The matrix was nylon-6 and the filler MMT. Because of its many advantages such as high mechanical properties, good gas barrier, flame retardation, etc. polymer/clay nano composites have been intensely investigated and is currently the subject of many research programs. Nano composite materials are commercially important and several types of products with different shapes and applications including food packaging films and containers, engine parts, dental materials, etc. are now available in markets. A number of synthesis routes have been developed in the recent years to prepare these materials, which include intercalation of polymers or prepolymers from solution, in-situ polymerization, melt intercalation etc. In this study, new nano composite materials were produced from the components of rubber (Nbr, SBR and EPDM) as the polymeric matrix and organically modified quaternary alkylammonium montmorillonite in different contents (3, 5, 7, and 10 phr) as the filler by using an extruder then, the rubber nano composite sheets were irradiated at a dose of 0, 50, 75, 100 and 150 KGy using Electron beam Irradiation technique as a crosslinking agent. These new materials can be characterized by using various analytical techniques including X-ray diffractometer XRD, Thermogravimetric analyzer TGA, scanning electron microscope (SEM), transmission electron microscope (TEM),Fourier transform

  11. Asphaltenes-based polymer nano-composites

    Science.gov (United States)

    Bowen, III, Daniel E

    2013-12-17

    Inventive composite materials are provided. The composite is preferably a nano-composite, and comprises an asphaltene, or a mixture of asphaltenes, blended with a polymer. The polymer can be any polymer in need of altered properties, including those selected from the group consisting of epoxies, acrylics, urethanes, silicones, cyanoacrylates, vulcanized rubber, phenol-formaldehyde, melamine-formaldehyde, urea-formaldehyde, imides, esters, cyanate esters, allyl resins.

  12. Microstructure and mechanical properties of aluminum–fly ash nano composites made by ultrasonic method

    International Nuclear Information System (INIS)

    Narasimha Murthy, I.; Venkata Rao, D.; Babu Rao, J.

    2012-01-01

    Highlights: ► Nano structured fly ash has been produced by 30 h milling time. ► Al–fly ash nano composites were produced by ultrasonic cavitation route. ► A homogeneous distribution of nano fly ash particles was observed in the matrix. ► No additional contamination in the nano composites from the atmosphere. ► Presence of nano fly ash leads to improvement in the strength of the composites. -- Abstract: In this paper an attempt has been made to modify the micro sized fly ash into nano structured fly ash using high energy ball mill. Ball milling was carried out for the total duration of 30 h. The sample was taken out after every 5 h of milling for characterizing. The nano structured fly ash was characterized for its crystallite size and lattice strain by using X-ray diffractometer. It was found that a steady decrease in the crystallite size and increased lattice strain was observed with milling time; the crystallite size at 30 h milling time was found to be 23 nm. The fresh fly ash particles are mostly spherical in shape; whereas the shape of the 30 h milled fly ash particles is irregular and the surface morphology is rough. Al–fly ash nano composites were produced by ultrasonic cavitation route successfully. Scanning electron microscopy images of nano composites reveal a homogeneous distribution of the nano fly ash particles in the AA 2024 matrix. Energy dispersive spectroscopy analysis of nano composites reveals that the fabricated nano composite did not contain any additional contamination from the atmosphere. As the amount of nano fly ash is increasing the hardness of the composite also increasing. The nano fly ash addition leads to improvement in the compression strength of the composites.

  13. Hybrid Nano composite Membranes for PEMFC Applications

    International Nuclear Information System (INIS)

    Niepceron, F.

    2008-03-01

    This work aims at validating a new concept of hybrid materials for the realization of proton exchange membranes, an essential constituent of PEM fuel cells. The originality of this nano-composite hybrid concept corresponds to a separation of the membrane's properties. We investigated the preparation of composite materials based on an inert, relatively low cost, polymer matrix (PVDF-HFP) providing the mechanical stability embedding inorganic fillers providing the necessary properties o f proton-conduction and water retention. The first step of this work consisted in the modification of fumed silica to obtain a proton-conducting filler. An ionic exchange capacity (CEI) equal to 3 meq/g was obtained by the original grafting of sodium poly(styrene-sulfonate) chains from the surface of particles. Nano-composite hybrid membranes PVDF-HFP/functionalized silica were accomplished by a film casting process. The coupling of the morphological and physicochemical analyses validated the percolation of the inorganic phase for 30 wt.% of particles. Beyond 40 % of loading, measured protonic conductivity is higher than the reference membrane Nafion 112. Finally, these membranes presented high performances, above 0.8 W/cm 2 , in single-cell fuel cell tests. A compromise is necessary according to the rate of loading between performances in fuel cell and mechanical properties of the membrane. 50 % appeared as best choice with, until 90 C, a remarkable thermal stability of the performances. (author)

  14. Effect of antimicrobial agents on cellulose acetate nano composites properties

    International Nuclear Information System (INIS)

    Rodriguez, Francisco J.; Bruna, Julio E.; Galotto, Maria J.; Guarda, Abel; Sepulveda, Hugo

    2011-01-01

    Nano composites based on cellulose acetate, Cloisite 30B, triethyl citrate and thymol or cinnamaldehyde were prepared using a dissolution casting technique. The effect of thymol and cinnamaldehyde on the cellulose acetate nano composite properties was evaluated by XRD and DSC. Important changes on the thermal properties and morphological structure were observed according to thymol and cinnamaldehyde content. (author)

  15. Effect of antimicrobial agents on cellulose acetate nano composites properties

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Francisco J.; Bruna, Julio E.; Galotto, Maria J.; Guarda, Abel; Sepulveda, Hugo, E-mail: francisco.rodriguez.m@usach.cl [Center for the Development of Nanoscience and Nanotechnology (CEDENNA). Universidad de Santiago de Chile. Faculty of Technology. Department of Food Science and Technology. Food Packaging Laboratory. Santiago (Chile)

    2011-07-01

    Nano composites based on cellulose acetate, Cloisite 30B, triethyl citrate and thymol or cinnamaldehyde were prepared using a dissolution casting technique. The effect of thymol and cinnamaldehyde on the cellulose acetate nano composite properties was evaluated by XRD and DSC. Important changes on the thermal properties and morphological structure were observed according to thymol and cinnamaldehyde content. (author)

  16. Surface enhanced 316L/SiC nano-composite coatings via laser cladding and following cold-swaging process

    Science.gov (United States)

    Li, Yuhang; Gao, Shiyou

    2017-10-01

    Cold-swaging is one of a cold deformation processes, and ceramic-reinforcement nano-composite coatings can effectively improve the performance of metal matrix surface. Therefore, the two processes are innovatively combined to further improve the surface properties of the metal matrix in this paper. The microstructure and surface properties of the laser cladding 316L + 10 wt% SiC nano-composite coatings were examined through designed experiments after cold-swaging by self-developed hydraulic machine. Furthermore, the coatings were compared with those without cold-swaging coatings at the same time. The result shows that the cold-swaging process can further enhance the tensile strength, micro-hardness and the wear resistance of the composite coating. This study can be used as a reference for further strengthening of laser cladding nano-composite coatings in future research.

  17. Preparation and characterization of PVC /ENR/CNTs Nano composites

    International Nuclear Information System (INIS)

    Ratnam, C.T.; Nur Azrini Ramlee; Keong, C.C.

    2011-01-01

    Poly (vinyl chloride), PVC/ epoxidized natural rubber blend, ENR/ carbon nano tubes, CNTs were prepared by using melt and solution blending methods. Addition of 2 phr of CNTs found to cause a drop in the tensile strength, Ts of the 50/ 50 PVC/ ENR blend. The nano composites prepared by the melt blending method exhibited higher values of Ts compared to the nano composites prepared by solution blending. Melt blending found to be an efficient method to prepare PVC/ ENR/ CNTs nano composites. (author)

  18. PREFACE: International Conference on Structural Nano Composites (NANOSTRUC 2012)

    Science.gov (United States)

    Njuguna, James

    2012-09-01

    Dear Colleagues It is a great pleasure to welcome you to NanoStruc2012 at Cranfield University. The purpose of the 2012 International Conference on Structural Nano Composites (NanoStruc2012) is to promote activities in various areas of materials and structures by providing a forum for exchange of ideas, presentation of technical achievements and discussion of future directions. NanoStruc brings together an international community of experts to discuss the state-of-the-art, new research results, perspectives of future developments, and innovative applications relevant to structural materials, engineering structures, nanocomposites, modelling and simulations, and their related application areas. The conference is split in 7 panel sessions, Metallic Nanocomposites and Coatings, Silica based Nanocomposites, safty of Nanomaterials, Carboin based Nanocomposites, Multscale Modelling, Bio materials and Application of Nanomaterials. All accepted Papers will be published in the IOP Conference Series: Materials Science and Engineering (MSE), and included in the NanoStruc online digital library. The abstracts will be indexed in Scopus, Compedex, Inspec, INIS (International Nuclear Information System), Chemical Abstracts, NASA Astrophysics Data System and Polymer Library. Before ending this message, I would like to acknowledge the hard work, professional skills and efficiency of the team which ensured the general organisation. As a conclusion, I would like to Welcome you to the Nanostruc2012 and wish you a stimulating Conference and a wonderful time. On behalf of the scientific committee, Signature James Njuguna Conference Chair The PDF of this preface also contains committee listings and associates logos.

  19. Flexural Properties of Activated Carbon Filled Epoxy Nano composites

    International Nuclear Information System (INIS)

    Khalil, H.P.S.A.; Khalil, H.P.S.A.; Alothman, O.Y.; Paridah, M.T.; Zainudin, E.S.

    2014-01-01

    Activated carbon (AC) filled epoxy nano composites obtained by mixing the desired amount of nano AC viz., bamboo stem, oil palm empty fruit bunch, and coconut shell from agricultural biomass with the epoxy resin. Flexural properties of activated carbons filled epoxy nano composites with 1 %, and 5 % filler loading were measured. In terms of flexural strength and modulus, a significant increment was observed with addition of 1 % vol and 5 % vol nano-activated carbon as compared to neat epoxy. The effect of activated carbon treated by two chemical agents (potassium hydroxide and phosphoric acid) on the flexural properties of epoxy nano composites were also investigated. Flexural strength of activated carbon-bamboo stem, activated carbon-oil palm, and activated carbon-coconut shell reinforced epoxy nano composites showed almost same value in case of 5 % potassium hydroxide activated carbon. Flexural strength of potassium hydroxide activated carbon-based epoxy nano composites was higher than phosphoric acid activated carbon. The flexural toughness of both the potassium hydroxide and phosphoric acid activated carbon reinforced composites range between 0.79 - 0.92 J. It attributed that developed activated carbon filled epoxy nano composites can be used in different applications. (author)

  20. Development of novel nano-composite membranes as introduction systems for mass spectrometers: Contrasting nano-composite membranes and conventional inlet systems

    Science.gov (United States)

    Miranda, Luis Diego

    This dissertation presents the development of novel nano-composite membranes as introduction systems for mass spectrometers. These nano-composite membranes incorporate anodic aluminum oxide (AAO) membranes as templates that can be used by themselves or modified by a variety of chemical deposition processes. Two types of nano-composite membranes are presented. The first nano-composite membrane has carbon deposited within the pores of an AAO membrane. The second nano-composite membrane is made by coating an AAO membrane with a thin polymer film. The following chapters describe the transmission properties these nano-composite membranes and compare them to conventional mass spectrometry introduction systems. The nano- composite membranes were finally coupled to the inlet system of an underwater mass spectrometer revealing their utility in field deployments.

  1. Rare-earth element doped Si3N4/SiC micro/nano-composites-RT and HT mechanical properties

    Czech Academy of Sciences Publication Activity Database

    Lojanová, Š.; Tatarko, P.; Chlup, Zdeněk; Hnatko, M.; Dusza, J.; Lenčéš, Z.; Šajgalík, P.

    2010-01-01

    Roč. 30, č. 9 (2010), s. 1931-1944 ISSN 0955-2219 Institutional research plan: CEZ:AV0Z20410507 Keywords : Si3N4 * SiC * Nano-composites * Fracture toughness * Hardness * Strength * Creep Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 2.574, year: 2010

  2. Functionalized Multi walled Carbon Nano tubes-Reinforced Viny lester/Epoxy Blend Based Nano composites: Enhanced Mechanical, Thermal, and Electrical Properties

    International Nuclear Information System (INIS)

    Praharaj, A. P.; Behera, D.; Bastia, T. K.; Rout, A. K.

    2015-01-01

    This paper presents a study on the mechanical, thermal, and electrical characterization of a new class of low cost multiphase nano composites consisting of Vinyl ester resin/epoxy (VER/EP) blend (40:60 w/w) reinforced with amine functionalized multi walled carbon nano tubes (f-MWCNTs). Five different sets of VER/EP nano composites are fabricated with addition of 0, 1, 3, 5, and 7 wt.% of f-MWCNTs. A detailed investigation of mechanical properties like tensile strength, impact strength, Young’s modulus, and hardness, thermal properties like thermogravimetric analysis (TGA) and thermal conductivity, electrical properties like dielectric strength, dielectric constant, and electrical conductivity, and corrosive and swelling properties of the nano composites has been carried out. Here, we report significant improvement in all the above properties of the fabricated nano composites with nano filler (f-MWCNTs) addition compared to the virgin blend (0 wt. nano filler loading). The properties are best observed in case of 5 wt.% nano filler loading with gradual deterioration thereafter which may be due to the nucleating tendency of the nano filler particles. Thus the above nano composites could be a preferable candidate for a wide range of structural, thermal, electrical, and solvent based applications.

  3. Synthesis of Metal Polymer Nano composites Using Ionizing Radiation

    International Nuclear Information System (INIS)

    Mostafa, R.S.S.

    2012-01-01

    we prepared a series of CdS/PVA and Ag/PVA nano composites via facile and novel synthetic steps. Our synthetic route is simpler; it does not need expensive oxidizing agents, surfactants, templates and complicated apparatus. The present work contains five chapters in addition to the list of figures, tables, abbreviations and references. The first two chapters are concerned with the introduction and reviews of previous studies. Chapter 3 describes the preparation methodology, experimental setup and techniques used in the CdS/PVA and Ag/PVA nano composites processing and analysis. CdS and Ag nanoparticles with different particle sizes were prepared via chemical method and gamma irradiation method. Several techniques were used to detect the structural changes of the nano composites due to interaction between CdS or Ag ions and PVA. These are: UV-Visible spectrophotometer, Transmission Electron microscope (TEM), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) Spectrophotometer, and thermogravimetric analysis. Chapter 4 includes the obtained results and their discussions: Ultraviolet/Visible spectroscopy (UV/VIS) investigated that the as-prepared nano composites have improved optical properties. Such incremented optical properties were attributed to the nano scale dispersion (nm). The improvement in the optical properties is considered to be dependent on, Cd 2+ :S 2- molar ratio, Ag concentration, Pva content and irradiation dose. The calculated band gap energies for CdS/PVA nano composites are higher than that of bulk of CdS indicating the strong quantum confinement. The increases in band gap energy have been attributed to the crystalline size dependent properties. Transmission electron microscope images illustrated that the nano structured CdS/PVA films were found to be dispersed spherical nanoparticles with good structural homogeneity and polydispersity at either lower concentration of CdCl 2 and/or irradiation dose. Nano rod structure of CdS accompanied

  4. Studies on structural properties of clay magnesium ferrite nano composite

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Manpreet, E-mail: manpreetchem@pau.edu; Singh, Mandeep [Department of Chemistry, Punjab Agricultural University, Ludhiana-141004 (India); Jeet, Kiran, E-mail: kiranjeet@pau.edu; Kaur, Rajdeep [Electron Microscopy and Nanoscience Laboratory, Punjab Agricultural University, Ludhiana-141004 (India)

    2015-08-28

    Magnesium ferrite-bentonite clay composite was prepared by sol-gel combustion method employing citric acid as complexing agent and fuel. The effect of clay on the structural properties was studied with X-ray diffraction (XRD), Fourier transform infrared (FT-IR) Spectroscopy, Scanning electron microscopy (SEM), SEM- Energy dispersive Spectroscope (EDS) and BET surface area analyzer. Decrease in particle size and density was observed on addition of bentonite clay. The BET surface area of nano composite containing just 5 percent clay was 74.86 m{sup 2}/g. Whereas porosity increased from 40.5 per cent for the pure magnesium ferrite to 81.0 percent in the composite showing that nano-composite has potential application as an adsorbent.

  5. Action of colloidal silica films on different nano-composites

    Directory of Open Access Journals (Sweden)

    S. Abdalla

    Full Text Available Nano-composite films have been the subject of extensive work to develop the energy-storage efficiency of electrostatic capacitors. Factors such as polymer purity, nano-particles size, and film morphology drastically affect the electrostatic efficiency of the dielectric material that form an insulating film between conductive electrodes of a capacitor. This in turn affects the energy storage performance of the capacitor. In the present work, we have studied the dielectric properties of 4 high pure amorphous polymer films: polymethylmethacrylate (PMMA, polystyrene, polyimide and poly-4-vinylpyridine. Comparison between the dielectric properties of these polymers has revealed that the higher break down performance is a character of polyimide PI and PMMA. Also, our experimental data shows that adding colloidal silica to PMMA and PI leads to a net decrease in the dielectric properties compared to the pure polymer. Keywords: Dielectric break down, Polymers, Nano-composite, Colloidal silica

  6. CO oxidation on Alsbnd Au nano-composite systems

    Science.gov (United States)

    Rajesh, C.; Majumder, C.

    2018-03-01

    Using first principles method we report the CO oxidation behaviour of Alsbnd Au nano-composites in three different size ranges: Al6Au8, Al13Au42 and a periodic slab of Alsbnd Au(1 1 1) surface. The clusters prefer enclosed structures with alternating arrangement of Al and Au atoms, maximising Auδ-sbnd Alδ+ bonds. Charge distribution analysis suggests the charge transfer from Al to Au atoms, corroborated by the red shift in the density of states spectrum. Further, CO oxidation on these nano-composite systems was investigated through both Eley - Rideal and Langmuir Hinshelwood mechanism. While, these clusters interact with O2 non-dissociatively with an elongation of the Osbnd O bond, further interaction with CO led to formation of CO2 spontaneously. On contrary, the CO2 evolution by co-adsorption of O2 and CO molecules has a transition state barrier. On the basis of the results it is inferred that nano-composite material of Alsbnd Au shows significant promise toward effective oxidative catalysis.

  7. Antimicrobial Properties of Chitosan-Alumina/f-MWCNT Nano composites

    International Nuclear Information System (INIS)

    Masheane, M.; Nthunya, L.; Malinga, S.; Masheane, M.; Nthunya, L.; Nxumalo, E.; Mhlanga, S.; Barnard, T.

    2016-01-01

    Antimicrobial chitosan-alumina/functionalized-multi walled carbon nano tube (f-MWCNT) nano composites were prepared by a simple phase inversion method. Scanning electron microscopy (SEM) analyses showed the change in the internal morphology of the composites and energy dispersive spectroscopy (EDS) confirmed the presence of alumina and f-MWCNTs in the chitosan polymer matrix. Fourier transform infrared (FTIR) spectroscopy showed the appearance of new functional groups from both alumina and f-MWCNTs, and thermogravimetric analysis (TGA) revealed that the addition of alumina and f-MWCNTs improved the thermal stability of the chitosan polymer. The presence of alumina and f-MWCNTs in the polymer matrix was found to improve the thermal stability and reduced the solubility of chitosan polymer. The prepared chitosan-alumina/f-MWCNT nano composites showed inhibition of twelve strains of bacterial strains that were tested. Thus, the nano composites show a potential for use as a biocides in water treatment for the removal of bacteria at different environmental conditions.

  8. Study on the nano-composite electroless coating of Ni-P/Ag

    International Nuclear Information System (INIS)

    Ma Hongfang; Tian Fang; Li Dan; Guo Qiang

    2009-01-01

    The nano-composite coating of Ni-P/Ag was obtained by adding silver nanoparticles to the Ni-P electroless plating solutions. The properties of the coating were tested by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), differential scanning calorimeter (DSC), X-ray diffraction (XRD) and microsclerometer. Silver nanoparticles changed the properties of the composite coating. The Ni-P electroless coating contains 12.23 wt.% P while the composite coating of Ni-P/Ag contains 11.17 wt.% P and 0.24 wt.% Ag. The hardness of the composite coating is bigger than that of Ni-P alloy coating. Differential scanning calorimeter studies showed the amorphous to crystalline transition with precipitation of Ni 3 P and Ni around 335 deg. C

  9. Study of the morphology exhibited by exfoliated polyurethane/montmorillonite nano composites during in situ recovery tests

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Iaci M., E-mail: iaci@ctex.eb.br [Divisao Belica do Centro Tecnologico do Exercito. CTEx, Rio de Janeiro, RJ (Brazil); Orefice, Rodrigo L. [Universidade Federal de Minas Gerais Departamento de Metalurgia e Materiais. UFMG, Belo Horizonte, MG (Brazil)

    2011-07-01

    By using small-angle X-ray scattering, this study aims to examine the SM behavior of montmorillonite polyurethane nano composites. To investigate the phase morphology, a deformed specimen was placed on a heating stage mounted at the Synchrotron beamline; the shape recovery was measured during 15 min. As temperature increases, the crystalline fraction rapidly decreases. The degree of clay delamination within the matrix increases, disturbing the formation of hard and soft segments. Deformation induces changes in the phase proportion, increasing the disperse phase contribution. During in situ tests, the ratio between matrix and disperse phase reaches an equilibrium controlled by the temperature. (author)

  10. Microstructure and Mechanical Properties of Multiphase Strengthened Al/Si/Al_2O_3/SiO_2/MWCNTs Nano composites Sintered by In Situ Vacuum Hot Pressing

    International Nuclear Information System (INIS)

    Li, J.; Jiang, X.; Zhu, D.; Zhu, M.; Shao, Z.; Johnson, S.; Luo, Z.

    2015-01-01

    Eutectic Al/Si binary alloy is technically one of the most important Al casting alloys due to its high corrosion resistance, evident shrinkage reduction, low thermal expansion coefficient, high fluidity, and good weldability. In this work, multi phased Al/Si matrix nano composites reinforced with Al_2O_3 and multi walled carbon nano tubes (MWCNTs) have been sintered by an in situ vacuum hot-pressing method. The alumina Al_2O_3 nanoparticles were introduced by an in situ reaction of Al with SiO_2. Microstructure and mechanical properties of the sintered Al/Si/Al_2O_3/SiO_2/MWCNTs nano composites with different alumina contents were investigated. The mechanical properties were determined by micro-Vickers hardness and compressive and shear strength tests. The results demonstrated that in situ alumina and MWCNTs had impacts on microstructure and mechanical properties of the nano composites. Based on the mechanical properties and microstructure of the nano composites, strengthening and fracture mechanisms by multiple reinforcements were analyzed

  11. Tribological behavior of Al-WC nano-composites fabricated by ultrasonic cavitation assisted stir-cast method

    Science.gov (United States)

    Pal, Arpan; Poria, Suswagata; Sutradhar, Goutam; Sahoo, Prasanta

    2018-03-01

    In the present study, the effects of WC nano-particles content on the microstructure, hardness, wear, and friction behavior of aluminum matrix composites are investigated. Al-WC nano composites with varying wt% of WC (0, 1, 1.5, and 2) are fabricated using ultrasonic cavitation assisted stir-cast method. The microstructure of the nano-composite samples is analyzed using optical microscopy and scanning electron microscopy. Elemental composition is determined by energy dispersive x-ray analysis. Vicker’s microhardness test is performed in different locations on the composite sample surface with a load of 50 gf and 10s dwell time. Wear and friction of the composites under dry sliding is studied using a pin-on-disk tribotester for varying normal load (10–40 N) and sliding speed (0.1–0.4 m/s). Uniform distribution of nano-WC is observed over composite surface without noticeable clustering. Reinforcement of nano-WC particles improves wear resistance and frictional behavior of the composite. Hardness is seen to increase with increase in wt% of nano-particles. Wear behavior of composites depends on formation of layers over the surface mixed with oxidized debris and counter-face particles. Wear mechanism changes from adhesion to abrasion with increase in wt% of hard nano particles.

  12. Preparation of organophilic clays and polypropylene nano composites

    International Nuclear Information System (INIS)

    Lima, Martha Fogliato S.; Nascimento, Vinicius G. do; Lenz, Denise M.; Schenato, Flavia

    2011-01-01

    Polypropylene/montmorillonite nano composites were prepared by the melt intercalation technique. The clay was organically modified with different quaternary ammonium salts to obtain the organo clay. The modified clays with the quaternary ammonium salts were introduced in a polypropylene matrix with 3 wt. % of clay. The interlayer distance (d001) of the clay particles were obtained by X- ray diffraction and the thermal stability of the systems were investigated by thermogravimetry. The organo clay presence in the polymer matrix increased the degradation temperature in relation to the pure polymer. (author)

  13. Effect of gamma radiation and accelerated aging on the mechanical and thermal behavior of HDPE/HA nano-composites for bone tissue regeneration.

    Science.gov (United States)

    Alothman, Othman Y; Almajhdi, Fahad N; Fouad, H

    2013-09-24

    The replacement of hard tissues demands biocompatible and sometimes bioactive materials with properties similar to those of bone. Nano-composites made of biocompatible polymers and bioactive inorganic nano particles such as HDPE/HA have attracted attention as permanent bone substitutes due to their excellent mechanical properties and biocompatibility. The HDPE/HA nano-composite is prepared using melt blending at different HA loading ratios. For evaluation of the degradation by radiation, gamma rays of 35 kGy, and 70 kGy were used to irradiate the samples at room temperature in vacuum. The effects of accelerated ageing after gamma irradiation on morphological, mechanical and thermal properties of HDPE/HA nano-composites were measured. In Vitro test results showed that the HDPE and all HDPE/HA nano-composites do not exhibit any cytotoxicity to WISH cell line. The results also indicated that the tensile properties of HDPE/HA nano-composite increased with increasing the HA content except fracture strain decreased. The dynamic mechanical analysis (DMA) results showed that the storage and loss moduli increased with increasing the HA ratio and the testing frequency. Finally, it is remarked that all properties of HDPE/HA is dependent on the irradiation dose and accelerated aging. Based on the experimental results, it is found that the addition of 10%, 20% and 30% HA increases the HDPE stiffness by 23%, 44 and 59% respectively. At the same time, the G' increased from 2.25E11 MPa for neat HDPE to 4.7E11 MPa when 30% HA was added to the polymer matrix. Also, significant improvements in these properties have been observed due to irradiation. Finally, the overall properties of HDPE and its nano-composite properties significantly decreased due to aging and should be taken into consideration in the design of bone substitutes. It is attributed that the developed HDPE/HA nano-composites could be a good alternative material for bone tissue regeneration due to their acceptable

  14. Eco-nano composite films containing copper as potential antimicrobial active packaging

    Energy Technology Data Exchange (ETDEWEB)

    Bruna, Julio E.; Gonzalez, Valeska; Rodriguez, Francisco; Guarda, Abel; Galotto, Maria Jose, E-mail: julio.bruna@usach.cl [Center for the Development of Nanoscience and Nanotechnology, Packaging Laboratory, University of Santiago de Chile. Santiago (Chile)

    2011-07-01

    The antimicrobial efficiency of Cellulose Acetate/MMTCu and Chitosan/MMTCu nano composites against Escherichia Coli 0157:H7 n/t has been studied in the present work. The MMT modified with copper were obtained using cation interchange in solution and the nano composites films were prepared using casting solution technique, being the biodegradable polymer (Cellulose Acetate or Chitosan) the main component and the montmorillonite modified with copper, the minority component. Characterization of MMTCu and the nano composites (CA/MMTCu and Ch/MMTCu), were carried out using XRD, AA, TGA, DSC and microbiological analysis. The nano composites showed to be more stable at higher temperature, resulting from the incorporation of MMTCu into the polymer. On the other hand, the results indicated that the antibacterial effect of nano composite increased with the proportion of MMTCu added. (author)

  15. Preparation of polymer-organo clay nano composites through the spray drying process

    International Nuclear Information System (INIS)

    Bernardo, Paulo R.A.; Pessan, Luiz A.; Carvalho, Antonio J.F. de; Vidotti, Suel E.

    2011-01-01

    The objective of the work was the study and preparation of polymer nano composites with montmorillonite organo clays (MMT) through the spray drying process. A new technique was proposed and tested to obtaining polymer nano composites, based on the use of the spray drying process to produce a nano composite with high clay content. The process consisted of the following stages: clay intercalation in water solution, with after addition of polyvinyl alcohol (PVOH) and a hydro soluble polyester ionomer (GEROLPS20) as exfoliation agents; spray drying the mixture obtained; incorporation powder in EVOH, PET e PP matrix. The effects of exfoliation agent on morphological and thermal properties of the nano composites were studied by XRD, transmission electron microscopy (TEM) and TGA. The results demonstrate that the process of spray drying is an innovative way to obtain a nano composite with high clay content. (author)

  16. Study on Carbon Nano composite Counter electrode for Dye-Sensitized Solar Cells

    International Nuclear Information System (INIS)

    Chen, Y.; Zhang, H.; Lin, J.

    2012-01-01

    Carbon nano composite electrodes were prepared by adding carbon nano tubes (CNTs) into carbon black as counter electrodes of dye-sensitized solar cells (DSSCs). The morphology and structure of carbon nano composite electrodes were studied by scanning electron microscopy. The influence of CNTs on the electrochemical performance of carbon nano composite electrodes is investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Carbon nano composite electrodes with CNTs exhibit a highly interconnected network structure with high electrical conductivity and good catalytic activity. The influence of different CNTs content in carbon nano composite electrodes on the open-circuit voltage, short-circuit current, and filling factor of DSSCs is also investigated. DSSCs with 10% CNTs content exhibit the best photovoltaic performance in our experiments.

  17. Eco-nano composite films containing copper as potential antimicrobial active packaging

    International Nuclear Information System (INIS)

    Bruna, Julio E.; Gonzalez, Valeska; Rodriguez, Francisco; Guarda, Abel; Galotto, Maria Jose

    2011-01-01

    The antimicrobial efficiency of Cellulose Acetate/MMTCu and Chitosan/MMTCu nano composites against Escherichia Coli 0157:H7 n/t has been studied in the present work. The MMT modified with copper were obtained using cation interchange in solution and the nano composites films were prepared using casting solution technique, being the biodegradable polymer (Cellulose Acetate or Chitosan) the main component and the montmorillonite modified with copper, the minority component. Characterization of MMTCu and the nano composites (CA/MMTCu and Ch/MMTCu), were carried out using XRD, AA, TGA, DSC and microbiological analysis. The nano composites showed to be more stable at higher temperature, resulting from the incorporation of MMTCu into the polymer. On the other hand, the results indicated that the antibacterial effect of nano composite increased with the proportion of MMTCu added. (author)

  18. Synthesis and characterization of aluminium–alumina micro- and nano-composites by spark plasma sintering

    International Nuclear Information System (INIS)

    Dash, K.; Chaira, D.; Ray, B.C.

    2013-01-01

    Graphical abstract: The evolution of microstructure by varying the particle size of reinforcement in the matrix employing spark plasma sintering has been demonstrated here in Al–Al 2 O 3 system. An emphasis has been laid on varying the reinforcement particle size and evaluating the microstructural morphologies and their implications on mechanical performance of the composites. Nanocomposites of 0.5, 1, 3, 5, 7 volume % alumina (average size 2 O 3 micro- and nano-composites fabricated by spark plasma sintering. • Better matrix-reinforcement integrity in nanocomposites than microcomposites. • Spark plasma sintering method results in higher density and hardness values. • High density and hardness values of nanocomposites than microcomposites. • High dislocation density in spark plasma sintered Al–Al 2 O 3 composites. - Abstract: In the present study, an emphasis has been laid on evaluation of the microstructural morphologies and their implications on mechanical performance of the composites by varying the reinforcement particle size. Nanocomposites of 0.5, 1, 3, 5, 7 volume % alumina (average size 2 O 3 nancomposites respectively. Spark plasma sintering imparts enhanced densification and matrix-reinforcement proximity which have been corroborated with the experimental results

  19. Modal analysis of pre and post impacted nano composite laminates

    Directory of Open Access Journals (Sweden)

    R. Velmurugan

    Full Text Available Modal analysis is carried out on pre and post impacted nano composite laminates. The laminates are prepared using 3, 5 and 8 layers of 610gsm glass woven roving mats(WRM with epoxy resin and montmorillonite(MMT clay content is varied from 1% to 5%. Impulse hammer technique is used to find natural frequency and damping factor of laminates. Medium velocity impact tests are conducted by using a gas gun. The vibration responses of natural frequency and damping factor are obtained and are studied for laminates with all edges clamped boundary conditions. Results show considerable improvement in natural frequency and damping factor due to nano clay addition. It is also seen that the nano clay controls the delamination due to impact loading.

  20. Stress development in particulate, nano-composite and polymeric coatings

    Science.gov (United States)

    Jindal, Karan

    2009-12-01

    The main goal of this research is to study the stress, structural and mechanical property development during the drying of particulate coatings, nano-composite coatings and VOC compliant refinish clearcoats. The results obtained during this research establish the mechanism for the stress development during drying in various coating systems. Coating stress was measured using a controlled environment stress apparatus based on cantilever deflection principle. The stress evolution in alumina coatings made of 0.4 mum size alumina particles was studied and the effect of a lateral drying was investigated. The stress does not develop until the later stages of drying. A peak stress was observed during drying and the peak stress originates due to the formation of pendular rings between the particles. Silica nanocomposite coatings were fabricated from suspension of nano sized silicon dioxide particles (20 nm) and polyvinyl alcohol (PVA) polymer. The stress in silica nano-composite goes through maximum as the amount of polymer in the coating increases. The highest final stress was found to be ˜ 110MPa at a PVA content of 60 wt%. Observations from SEM, nitrogen gas adsorption, camera imaging, and nano-indentation were also studied to correlate the coatings properties during drying to measured stress. A model VOC compliant two component (2K) acrylic-polyol refinish clearcoat was prepared to study the effects of a new additive on drying, curing, rheology and stress development at room temperature. Most of the drying of the low VOC coatings occurred before appreciable (20%) crosslinking. Tensile stress developed in the same timeframe as drying and then relaxed over a longer time scale. Model low VOC coatings prepared with the additive had higher peak stresses than those without the additive. In addition, rheological data showed that the additive resulted in greater viscosity buildup during drying.

  1. Performance enhancement of quantum dot-sensitized solar cells based on polymer nano-composite catalyst

    International Nuclear Information System (INIS)

    Seo, Hyunwoong; Gopi, Chandu V.V.M.; Kim, Hee-Je; Itagaki, Naho; Koga, Kazunori; Shiratani, Masaharu

    2017-01-01

    Highlights: •We studied polymer nano-composite containing TiO 2 nano-particles as a catalyst. •Polymer nano-composite was applied for quantum dot-sensitized solar cells. •Polymer nano-composite catalyst was considerably improved with TiO 2 nano-particles. •Polymer nano-composite showed higher photovoltaic performance than conventional Au. -- Abstract: Polymer nano-composite composed of poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) and TiO 2 nano-particles was deposited on fluorine-doped tin oxide substrate and applied as an alternative to Au counter electrode of quantum dot-sensitized solar cell (QDSC). It became surface-richer with the increase in nano-particle amount so that catalytic reaction was increased by widened catalytic interface. Electrochemical impedance spectroscopy and cyclic voltammetry clearly demonstrated the enhancement of polymer nano-composite counter electrode. A QDSC based on polymer nano-composite counter electrode showed 0.56 V of V OC , 12.24 mA cm −2 of J SC , 0.57 of FF, and 3.87% of efficiency and this photovoltaic performance was higher than that of QDSC based on Au counter electrode (3.75%).

  2. Gamma radiation effects on nano composites of Ag nanoparticles in Zn O matrices

    International Nuclear Information System (INIS)

    Villasenor C, L. S.

    2015-01-01

    The study of gamma radiation effects in nano composites of silver nanoparticles in a Zn O matrix has been performed in this work. First, silver nanoparticles (AgNPs) were synthesized by colloidal methods, with two different mean average sizes, 48 nm and 24 nm respectively. These nanoparticles were characterized by transmission electron microscopy (Tem) and UV-Vis spectroscopy (UV-Vis). Then, with the synthesized AgNPs, nano composites in a matrix of Zn O were prepared. The first nano composite was prepared with the 48 nm AgNPs at 9.5 weight % of silver (Ag) and the second nano composite with the 24 nm nanoparticles at 1.0 weight % of Ag. Both nano composites were analyzed by scanning electron microscopy (Sem). The formation of the Zn O phase in the nano composite was corroborated through X-ray diffraction analysis. It was observed that the presence of AgNPs during the formation of the AgNPs/Zn O nano composite modified the size and morphology of the structures obtained compared to those of the pure Zn O without nanoparticles, however both exhibit a radial structure. Then, the nano composite at 9.5 weight % of Ag was irradiated with gamma rays at doses of 1, 20 and 50 kGy. Samples were analyzed by Sem and the Bet technique, before and after being irradiated, in order to determine the effect of gamma radiation in the morphology, porosity and surface area of the studied material. Even when there are changes in porosity and Surface area, this difference is not very significant for some applications, however it will have to be considered during the design of a specific application of the nano composites. On the other hand, no morphology modifications were identified on the samples irradiated at the studied doses, with the electron microscopy techniques used. (Author)

  3. Study of thermal properties and the dispersion state of nano composites epoxy/clay

    International Nuclear Information System (INIS)

    Paz, Juliana D.; Bertholdi, Jonas; Toledo, Tais C.; Folgueras, Marilena V.; Pezzin, Sergio H.; Coelho, Luiz A.F.

    2011-01-01

    This work investigates an exfoliation/intercalation of nano clays in an epoxy resin by means of x-rays diffraction, scanning electronic microscopy, thermal gravimetric analysis and dilatometric analysis. A comparison of two techniques for preparing nano composites is addressed: mechanical stirring and sonication. X-rays analysis showed that an exfoliation/intercalation is occurring in some samples. TG analysis indicated and increase in thermal stability of the nano composites compared to the neat resin. Finally, dilatometric analysis indicates and increase in Tg for nano composites compared to the neat resin. (author)

  4. Effect of organo clay addition on thermal properties of poly lactide/ polycaprolactone (PLA/ PCL) nano composites

    International Nuclear Information System (INIS)

    Siti Zulaiha Hairaldin; Wan Md Zin Wan Yunus; Norazoma Ibrahim

    2010-01-01

    In this study, melt blending technique was applied to prepare poly lactide/polycaprolactone (PLA/ PCL) nano composites with various blends. Montmorillonite (MMT) was used as an addition to the matrix. In this study, melt blending technique was applied to prepare poly lactide/polycaprolactone (PLA/ PCL) nano composites. Montmorillonite (MMT) was used as an addition to the matrix with various percentages. The other one is modified clay prepared by modifying the nature of montmorillonite with octadecylamine (ODA) to improve the characteristic of PLA/ PCL blends. X-ray diffraction (XRD) results indicated intercalation of the PLA/ PCL into silicate nano size interlayers galleries of the nano composites. The presence of modified clays in nano composite was confirmed by FTIR spectrum. TGA and DTG results show addition of MMT and modified clay ODA-MMT improved the thermal stability of the PLA/ PCL blends. (author)

  5. Development of nano-composite membranes to improve alkaline fuel cell performance

    CSIR Research Space (South Africa)

    Nonjola, P

    2011-09-01

    Full Text Available The work presented here describes modification of commercially available polysulfone (PSU) as well as the formation of nano-composite membrane i.e. TiO2 nano particles incorporated into anion exchange polymer matrix....

  6. Nuclear magnetic resonance applied to the study of polymeric nano composites

    International Nuclear Information System (INIS)

    Tavares, Maria Ines Bruno

    2011-01-01

    Polymers and nanoparticles based nano composites were prepared by intercalation by solution. The obtained nano composites were characterized mainly by the nuclear magnetic spectroscopy (NMR), applying the analysis of carbon-13 (polymeric matrix), silicon-29 (nanoparticle), and by determination of spin-lattice relaxation of the hydrogen nucleus (T 1 H) (polymeric matrix). The NMR have presented a promising technique in the characterization of the nano charge dispersion in the studied polymeric matrixes.

  7. Some Fundamental Aspects of Mechanics of Nano composite Materials and Structural Members

    International Nuclear Information System (INIS)

    Guz, A.N.; Rushchitsky, J.J.

    2013-01-01

    This paper is devoted to formulation and analysis of fundamental aspects of mechanics of nano composite materials and structural members. These aspects most likely do not exhaust all of the possible fundamental characteristics of mechanics of nano composite materials and structural members, but, nevertheless, they permit to form the skeleton of direction of mechanics in hand. The proposed nine aspects are described and commented briefly.

  8. Optical Properties and Surface Morphology of Nano-composite PMMA: TiO2 Thin Films

    International Nuclear Information System (INIS)

    Lyly Nyl Ismail; Ahmad Fairoz Aziz; Habibah Zulkefle

    2011-01-01

    There are two nano-composite PMMA: TiO 2 solutions were prepared in this research. First solution is nano-composite PMMA commercially available TiO 2 nanopowder and the second solution is nano-composite PMMA with self-prepared TiO 2 powder. The self-prepared TiO 2 powder is obtained by preparing the TiO 2 sol-gel. Solvo thermal method were used to dry the TiO 2 sol-gel and obtained TiO 2 crystal. Ball millers were used to grind the TiO 2 crystal in order to obtained nano sized powder. Triton-X was used as surfactant to stabilizer the composite between PMMA: TiO 2 . Besides comparing the nano-composite solution, we also studied the effect of the thin films thickness on the optical properties and surface morphology of the thin films. The thin films were deposited by sol-gel spin coating method on glass substrates. The optical properties and surface characterization were measured with UV-VIS spectrometer equipment and atomic force microscopy (AFM). The result showed that nano-composite PMMA with self prepared TiO 2 give high optical transparency than nano-composite PMMA with commercially available TiO 2 nano powder. The results also indicate as the thickness is increased the optical transparency are decreased. Both AFM images showed that the agglomerations of TiO 2 particles are occurred on the thin films and the surface roughness is increased when the thickness is increased. High agglomeration particles exist in the AFM images for nano-composite PMMA: TiO 2 with TiO 2 nano powder compare to the other nano-composite solution. (author)

  9. Development and evaluation of fast forming nano-composite hydrogel for ocular delivery of diclofenac.

    Science.gov (United States)

    Li, Xingyi; Zhang, Zhaoliang; Chen, Hao

    2013-05-01

    In this paper, a fast forming nano-composite hydrogel was developed for potential application in ocular drug delivery. The optical transmission (OT) as well as rheological properties of nano-composite hydrogel was characterized. The developed nano-composite hydrogel given a high diclofenac micelles loading and provided a sustained release manner of diclofenac within 6h. The developed nano-composite hydrogel formulation was administrated into the eye as flowable solution, quickly forming a hydrogel that is able to resist of the blinking and flushing of tear, yet resulting in the prolonged residence time of pre-corneal. In vivo eye irritation test suggested that the developed nano-composite hydrogel was none-eye irritation might be suitable for various ocular applications. In vivo pharmacokinetic study indicated that the developed nano-composite hydrogel could significantly increase the bioavailability of diclofenac and maintain the concentration of diclofenac in aqueous humor above MEC at least 24h after administration as compared with that of the commercial diclofenac sodium eye drops, which might be able to reduce the frequency of administration for patients. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. LDPE/HDPE/Clay Nano composites: Effects of Compatibilizer on the Structure and Dielectric Response

    International Nuclear Information System (INIS)

    David, Z.E.; Ngo, A.D.

    2013-01-01

    PE/clay nano composites were prepared by mixing a commercially available premixed polyethylene/O-MMT master batch into a polyethylene blend matrix containing 80 wt% low-density polyethylene and 20 wt% high-density polyethylene with and without anhydride modified polyethylene (PE-MA) as the compatibilizer using a corotating twin-screw extruder. In this study, the effect of nano clay and compatibilizer on the structure and dielectric response of PE/clay nano composites has been investigated. The microstructure of PE/clay nano composites was characterized using wide-angle X-ray diffraction (WAXD) and a scanning electron microscope (SEM). Thermal properties were examined using differential scanning calorimetry (DSC). The dielectric response of neat PE was compared with that of PE/clay nano composite with and without the compatibilizer. The XRD and SEM results showed that the PE/O-MMT nano composite with the PE-MA compatibilizer was better dispersed. In the nano composite materials, two relaxation modes are detected in the dielectric losses. The first relaxation is due to a Maxwell-Wagner-Sillars interfacial polarization, and the second relaxation can be related to dipolar polarization. A relationship between the degree of dispersion and the relaxation rate f m ax of Maxwell-Wagner-Sillars was found and discussed.

  11. Preparation, Characterization, and Modeling of Carbon Nano fiber/Epoxy Nano composites

    International Nuclear Information System (INIS)

    Sun, L.H.; Yang, Z.G.; Ounaies, Z.; Whalen, C.A.; Gao, X.L.

    2011-01-01

    There is a lack of systematic investigations on both mechanical and electrical properties of carbon nano fiber (CNF)-reinforced epoxy matrix nano composites. In this paper, an in-depth study of both static and dynamic mechanical behaviors and electrical properties of CNF/epoxy nano composites with various contents of CNFs is provided. A modified Halpin-Tsai equation is used to evaluate the Young's modulus and storage modulus of the nano composites. The values of Young's modulus predicted using this method account for the effect of the CNF agglomeration and fit well with those obtained experimentally. The results show that the highest tensile strength is found in the epoxy nano composite with a 1.0 wt % CNFs. The alternate-current (AC) electrical properties of the CNF/epoxy nano composites exhibit a typical insulator-conductor transition. The conductivity increases by four orders of magnitude with the addition of 0.1 wt % (0.058 vol %) CNFs and by ten orders of magnitude for nano composites with CNF volume fractions higher than 1.0 wt % (0.578 vol %). The percolation threshold (i.e., the critical CNF volume fraction) is found to be at 0.057 vol %.

  12. Nano-Composite Foam Sensor System in Football Helmets.

    Science.gov (United States)

    Merrell, A Jake; Christensen, William F; Seeley, Matthew K; Bowden, Anton E; Fullwood, David T

    2017-12-01

    American football has both the highest rate of concussion incidences as well as the highest number of concussions of all contact sports due to both the number of athletes and nature of the sport. Recent research has linked concussions with long term health complications such as chronic traumatic encephalopathy and early onset Alzheimer's. Understanding the mechanical characteristics of concussive impacts is critical to help protect athletes from these debilitating diseases and is now possible using helmet-based sensor systems. To date, real time on-field measurement of head impacts has been almost exclusively measured by devices that rely on accelerometers or gyroscopes attached to the player's helmet, or embedded in a mouth guard. These systems monitor motion of the head or helmet, but do not directly measure impact energy. This paper evaluates the accuracy of a novel, multifunctional foam-based sensor that replaces a portion of the helmet foam to measure impact. All modified helmets were tested using a National Operating Committee Standards for Athletic Equipment-style drop tower with a total of 24 drop tests (4 locations with 6 impact energies). The impacts were evaluated using a headform, instrumented with a tri-axial accelerometer, mounted to a Hybrid III neck assembly. The resultant accelerations were evaluated for both the peak acceleration and the severity indices. These data were then compared to the voltage response from multiple Nano Composite Foam sensors located throughout the helmet. The foam sensor system proved to be accurate in measuring both the HIC and Gadd severity index, as well as peak acceleration while also providing additional details that were previously difficult to obtain, such as impact energy.

  13. Study of Ion Transport Behaviour in (PVA-NH4I):SIO2 Nano Composite Polymer Electrolyte

    Science.gov (United States)

    Tripathi, Mridula; Trivedi, Shivangi; Upadhyay, Ruby; Singh, Markandey; Pandey, N. D.; Pandey, Kamlesh

    2013-07-01

    Development and characterization of Poly vinyl alcohol (PVA) based nano composite polymer electrolytes comprising of (PVA-NH4I):SiO2 is reported. Sol-gel derived silica powder of nano dimension has been used as ceramic filler for development of nano composite electrolyte. Formation of nano composites, change in the structural and microscopic properties of the system have been investigated by X-ray differaction, SEM and conductivity.

  14. A comparison study of polymer/cobalt ferrite nano-composites synthesized by mechanical alloying route

    Directory of Open Access Journals (Sweden)

    Sedigheh Rashidi

    2015-12-01

    Full Text Available In this research, the effect of different biopolymers such as polyethylene glycol (PEG and polyvinylalcohol (PVA on synthesis and characterization of polymer/cobalt ferrite (CF nano-composites bymechanical alloying method has been systematically investigated. The structural, morphological andmagnetic properties changes during mechanical milling were investigated by X-ray diffraction (XRD,Fourier transform infrared spectroscopy (FTIR, transmission electron microscopy (TEM, fieldemission scanning electron microscopy (FESEM, and vibrating sample magnetometer techniques(VSM, respectively. The polymeric cobalt ferrite nano-composites were obtained by employing atwo-step procedure: the cobalt ferrite of 20 nm mean particle size was first synthesized by mechanicalalloying route and then was embedded in PEG or PVA biopolymer matrix by milling process. Theresults revealed that PEG melted due to the local temperature raise during milling. Despite thisphenomenon, cobalt ferrite nano-particles were entirely embedded in PEG matrix. It seems, PAV is anappropriate candidate for producing nano-composite samples due to its high melting point. InPVA/CF nano-composites, the mean crystallite size and milling induced strain decreased to 13 nm and0.48, respectively. Moreover, milling process resulted in well distribution of CF in PVA matrix eventhough the mean particle size of cobalt ferrite has not been significantly affecetd. FTIR resultconfirmed the attachment of PVA to the surface of nano-particles. Magnetic properties evaluationshowed that saturation magnetization and coercivity values decreased in nano-composite samplecomparing the pure cobalt ferrite.

  15. Comparison of the mechanical properties between carbon nanotube and nanocrystalline cellulose polypropylene based nano-composites

    International Nuclear Information System (INIS)

    Huang, Jun; Rodrigue, Denis

    2015-01-01

    Highlights: • SWCNT and NCC can effectively improve the mechanical properties of nano-composites. • SWCNT is more effective than NCC to increase modulus and strength. • Longer NCC is more effective to improve the mechanical properties of nano-composites. • It is more economic to use NCC than SWCNT to improve mechanical properties. - Abstract: Using beam and tetrahedron elements to simulate nanocrystalline cellulose (NCC), single wall carbon nanotube (SWCNT) and polypropylene (PP), finite element method (FEM) is used to predict the mechanical properties of nano-composites. The bending, shear and torsion behaviors of nano-composites are especially investigated due to the limited amount of information in the present literature. First, mixed method (MM) and FEM are used to compare the bending stiffness of NCC/PP and SWCNT/PP composites. Second, based on mechanics of materials, the shear moduli of both types of nano-composites are obtained. Finally, fixing the number of fibers and for different volume contents, four NCC lengths are used to determine the mechanical properties of the composites. The bending and shearing performances are also compared between NCC and SWCNT based composites. In all cases, the elastic–plastic analyses are carried out and the stress or strain distributions for specific regions are also investigated. From all the results obtained, an economic analysis shows that NCC is more interesting than SWCNT to reinforce PP

  16. Functional properties of extruded nano composites based on cassava starch, polyvinyl alcohol and montmorillonite

    International Nuclear Information System (INIS)

    Debiagi, Flavia; Mali, Suzana

    2011-01-01

    The objectives of this work were to produce expanded nano composites (foams) based on starch, PVA and sodium montmorillonite and characterize them according to their expansion index (EI), density, water absorption capacity (WSC), mechanical properties and X-ray diffraction. The nano composites were prepared in a single-screw extruder using different starch contents (97.6 - 55.2 g/100 g formulation), PVA (0 - 40 g/100 g formulation), unmodified nano clay - Closite - Na (0 - 4. 8 g/100 g formulation) and glycerol (20 g/100 g formulation) as plasticizer. The addition of montmorillonite and PVA resulted in an increase of EI and a decrease of density of the samples, and reduced WSC and increased the mechanical strength of the foams. Through the analysis of X-ray diffraction can be observed that the addition of montmorillonite led to production of intercalated nano composites in all samples. (author)

  17. Chemically designed Pt/PPy nano-composite for effective LPG gas sensor.

    Science.gov (United States)

    Gaikwad, Namrata; Bhanoth, Sreenu; More, Priyesh V; Jain, G H; Khanna, P K

    2014-03-07

    Simultaneous in situ reduction of hexachloroplatinic acid by the amine group in the pyrrole monomer and oxidation of pyrrole to form polypyrrole (PPy) was examined. The reactions were performed at various temperatures to understand the degree of reduction of platinum precursor as well as doping of polypyrrole with Pt(II) chloro-complex. Spectroscopic images revealed different morphologies for the Pt/PPy nano-composite prepared at various temperatures. The as-prepared Pt/PPy nano-composite samples were tested for their ability to sense liquefied petroleum gas (LPG) which resulted in excellent sensing at relatively low temperature. The porous nature and ohmic contact between the PPy and platinum nanoparticles makes the as-prepared Pt/PPy nano-composite highly useful for sensors as well as electronic applications.

  18. Evaluation of the acquirement of nano composites of polypropylene and a bentonite organophilized by different methodologies

    International Nuclear Information System (INIS)

    Paiva, Lucilene B. de; Morales, Ana R.; Branciforti, Marcia C.; Bretas, Rosario E.S.

    2009-01-01

    This work describes the organophilization of an argentinean sodium bentonite with a quaternary ammo nium salt, by two methodologies: cation exchange in aqueous dispersion and intercalation in semi-solid medium. The modified samples were used in the preparation of nano composites, with polypropylene as a matrix and polypropylene-graft-maleic anhydride as a coupling agent, through melt intercalation by using a twin-screw micro extruder. The organophilic bentonites were characterized by the swelling capacity test in water and in xylene and by X-ray diffraction, and the nano composites were characterized by X-ray diffraction and transmission electronic microscopy. The results showed that were obtained nano composites with structures partially intercalated and exfoliated. (author)

  19. Optical properties study of nano-composite filled D shape photonic crystal fibre

    Directory of Open Access Journals (Sweden)

    R. Udaiyakumar

    2018-06-01

    Full Text Available With the nano-composite materials gaining momentum in the optical field, a new nano-composite filled D shape Photonic Crystal Fiber (PCF is designed and the various optical properties are investigated with help of Finite Element Method. In the proposed structure the D-shape PCF is made up of silica with embedded silver nanoparticles and air holes are distributed along the fibre. The designed fibre shows various optical properties such as dispersion, birefringence, beat length and loss with respect to wavelength and compared with different filling factor like 0.1, 0.3 and 0.5. From our estimation and comparative analysis, it has been proved that the fibre loss has been decreased with increasing filling factor. Further this also showed flat dispersion at maximum filling factor. Keywords: Nanoparticles, Nano-composite, Dispersion, Birefringence, Beat length

  20. Synthesis of Poly aniline-Montmorillonite Nano composites Using H2O2 as the Oxidant

    International Nuclear Information System (INIS)

    Binitha, N.; Binitha, N.; Suraja, V.; Zahira Yaakob; Sugunan, S.

    2011-01-01

    Poly aniline montmorillonite nano composite was prepared using H 2 O 2 as the oxidant. The catalytic environment of montmorillonite favours polymerization. Intercalation and composite formation was proven from various techniques such as XRD, FTIR, DRS and thermal analysis. XRD patterns give the dimension of the intercalated PANI, from the shift of 2θ values, which is in the nano range. FTIR showed that PANI composite formation occurred without affecting the basic clay layer structure. Thus the successful development of an alternative cheap route for poly aniline-montmorillonite nano composite was well established. (author)

  1. Chemical Functionalization, Self-Assembly, and Applications of Nano materials and Nano composites 2014

    International Nuclear Information System (INIS)

    Yan, X.; Jiao, T.; Balan, L.; Chen, X.; Hu, M.Z.; Liu, W.

    2014-01-01

    The growing interests in nano materials and nano composites call for the development of processing techniques to obtain multiple functionalization nano structures and achieve the tailoring of specific features of the nanometer size. Functional nano materials and nano composites will expand the applied range of the original material and at the same time promote the development of inter discipline. Thus, the chemical functionalization and bottom-up assemblies of nano materials and subsequent applications will accelerate the development of nano science and nano technology.

  2. Preliminary characterization in the development of the nano composite low density polyethylene with attapulgite clay

    International Nuclear Information System (INIS)

    Domingos, Luanda G.; Rego, Jose K.M.A. do; Ito, Edson N.; Acchar, Wilson

    2011-01-01

    The aim of this study was a preliminary study of the physical, thermal and rheological properties of the materials to be used in the development of nano composite low density polyethylene (LDPE) with Brazilian attapulgite clay (ATP), with and without the use of a compatibilizing agent interfacial, polyethylene grafted with maleic anhydride (PE-g-MAH). The materials were characterized by X-ray diffraction (XRD), thermogravimetry (TG) and torque rheometry. The materials were characterized and potentially could be developed polymeric nano composites with technological applications using attapulgite fibers in the nanometer scale. (author)

  3. Structural and Magnetic Properties of Type-M Barium Ferrite - Thermoplastic Natural Rubber Nano composites

    International Nuclear Information System (INIS)

    Nurhidayaty Mokhtar

    2012-01-01

    Structural and magnetic properties of type-M barium ferrite (BaFe 12 O 19 ) nanoparticles (∼ 20 nm) embedded in non-magnetic thermoplastic natural rubber (TPNR) matrices were investigated. The TPNR matrices were prepared from high density polyethylene (HDPE) and natural rubber (NR) in the weight ratios of 80:20 and 60:40, respectively, with 10 wt % of NR in the form of liquid natural rubber (LNR) which act as a comparabilities. BaFe 12 O 19 - filled nano composites with 2 - 12 wt % BaFe 12 O 19 ferrite were prepared using a melt- blending technique. Magnetic hysteresis was measured using a vibrating sample magnetometer (VSM) in a maximum field of 10 kOe at room temperature (25 degree Celsius). The saturation magnetisation (MS), remanence (MR) and coercivity (Hc) were derived from the hysteresis loops. The results show that the structural and magnetic properties of nano composites depend on both the ferrite content and the composition of the natural rubber or plastic in the nano composites. All the nano composites exhibit an exchange bias-like phenomenon resulting from the exchange coupling of spins at the interface between the core ferrimagnetic region and the disordered surface region of the nanoparticles. (author)

  4. Characterization of nano-composite PVD coatings for wear-resistant applications

    NARCIS (Netherlands)

    Galvan, D.; Pei, Y.T.; de Hosson, J.T.M.; DeHosson, JTM; Brebbia, CA; Nishida, SI

    2005-01-01

    Various methodologies for the characterization of nano-composite coatings are discussed, which consist TiC nano-particles distributed in an amorphous hydrocarbon (a-C:H) matrix. Complications that arise from the influence of coating roughness and underlying substrate on the properties are evaluated

  5. Preparation and characterization of poly(lactic acid)/ zinc-aluminium layered double hydroxide nano composites

    International Nuclear Information System (INIS)

    Eili Mahboobeh; Wan Mohd Zin Wan Yunus; Zobir Hossein; Mansor Ahmad; Norazowa Ibrahim

    2009-01-01

    Full text: Poly (lactic acid)/ stearate - zinc aluminum layered double hydroxide/ (PLA/ SZnAl LDH) nano composites were prepared via solution intercalation process using a modified ZnAl LDH. The anionic clay Zn 3 Al-NO 3 -LDH was prepared by a co-precipitation method and then modified with stearate ions by ion exchange process. Stearate-ZnAl LDH particles were then homogeneously dispersed in PLA matrix by a solution casting method. The pristine and modified ZnAl LDH was characterized by X-ray diffraction (XRD) and Fourier transforms infrared (FTIR) spectroscopy which suggested that the modification was successful. The XRD analysis showed that during modification of LDH, the basal spacing increased from 8.83 Angstrom to 40.1 Angstrom. The PLA/ ZnAl LDH nano composites were characterized by tensile testing and XRD. The obtained nano composites showed dramatic enhancements in elongation at break as compared to those of the pure PLA. XRD results indicated that the materials formed are nano composites. (author)

  6. Radiation Processing of Active Biodegradable Green Nano Composite Materials for Packaging Purposes

    International Nuclear Information System (INIS)

    AbdEl-Rehim, Hassan A.; Hegazy, El-Sayed A.; Raafat, Ahmed

    2011-01-01

    Clean and green reduction process of silver ions and graphene (GO) into nanosilver metal and graphene (GR) nanosheets respectively was achieved via gamma irradiation. The efficiency of gamma radiation to reduce silver ions and graphene oxide (GO) was investigated using UV-vis spectroscopy. Effects of gaseous atmosphere type, dispersion pH value, capping agent type and irradiation dose on GR nano-sheets formation were investigated. The presence of capping agent such as sodium carboxymethyl cellulose (CMC) or cellulose acetate is proven to be crucial. The obtained GR nanosheets and nanosilver metals are characterized using atomic force microscopy (AFM), transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (XRD) as well as thermo-gravimetric analyzer (TGA) and differential scanning calorimeter (DSC). Effectiveness, simplicity, reproducibility, and low energy consumption are the merits of using the Gamma radiation technique. Furthermore, the capping agent is eco-friendly and the dispersion is stable for months at room temperature. This approach can open up large-scale production of GR nanosheets and nanosilver metals. The prepared Nano-silver can be mixed with different natural polymer like CA to form Nano-composite films. The excellent physical properties of CA did not affect by addling Ag. The ionizing radiation has un-significant effect on the properties of CA-Ag nano composites films The CA-Ag nano composites posses biological activity towards different microorganisms. On other hand graphene or graphene oxide dispersions might be of interesting for producing biological active packaging films. Go as nanofillers has used for fabrication of a biocomposite with chitosan. The significantly improved in Chitosan /Go nano composites physical properties, including mechanical property, electrical conductivity, and structural stability, was demonstrated. Properties of the CA-Ag and Chitosan /Go nano composites suggest

  7. Radiation Processing of Active Biodegradable Green Nano Composite Materials for Packaging Purposes

    Energy Technology Data Exchange (ETDEWEB)

    AbdEl-Rehim, Hassan A.; Hegazy, El-Sayed A.; Raafat, Ahmed [National Center for Radiation Research and Technology NCRRT, Atomic Energy Authority, Cairo, Egypt P. O. Box 29, Nasr City, Cairo (Egypt)

    2011-07-01

    Clean and green reduction process of silver ions and graphene (GO) into nanosilver metal and graphene (GR) nanosheets respectively was achieved via gamma irradiation. The efficiency of gamma radiation to reduce silver ions and graphene oxide (GO) was investigated using UV-vis spectroscopy. Effects of gaseous atmosphere type, dispersion pH value, capping agent type and irradiation dose on GR nano-sheets formation were investigated. The presence of capping agent such as sodium carboxymethyl cellulose (CMC) or cellulose acetate is proven to be crucial. The obtained GR nanosheets and nanosilver metals are characterized using atomic force microscopy (AFM), transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (XRD) as well as thermo-gravimetric analyzer (TGA) and differential scanning calorimeter (DSC). Effectiveness, simplicity, reproducibility, and low energy consumption are the merits of using the Gamma radiation technique. Furthermore, the capping agent is eco-friendly and the dispersion is stable for months at room temperature. This approach can open up large-scale production of GR nanosheets and nanosilver metals. The prepared Nano-silver can be mixed with different natural polymer like CA to form Nano-composite films. The excellent physical properties of CA did not affect by addling Ag. The ionizing radiation has un-significant effect on the properties of CA-Ag nano composites films The CA-Ag nano composites posses biological activity towards different microorganisms. On other hand graphene or graphene oxide dispersions might be of interesting for producing biological active packaging films. Go as nanofillers has used for fabrication of a biocomposite with chitosan. The significantly improved in Chitosan /Go nano composites physical properties, including mechanical property, electrical conductivity, and structural stability, was demonstrated. Properties of the CA-Ag and Chitosan /Go nano composites suggest

  8. Multiphase Nano-Composite Coatings for Achieving Energy Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Nainaparampil, Jose

    2012-03-26

    UES Inc. and ANL teamed in this work to develop novel coating systems for the protection of surfaces from thermal degradation mainly in two applications; Machining and Die casting. These coatings were specifically designed for the purpose by incorporating required material phases and the overall architecture, which led to reduce the energy usage and increase efficiency of the operations. Following the UES/ANL's feasibility work, the coatings were developed utilizing High power impulse magnetron sputtering (HiPMS) and Large area filtered arc deposition (LAFAD) techniques. Toughness, hardness and oxidation resistance: contrasting qualities have been mixed in the right proportion to attain the suitable material characteristic for the cause. Hafnium diboride (HfB2) based materials provided such a system and its properties were tamed to attain the right combination of toughness and hardness by working on the microstructure and architecture of coatings. An effective interfacing material (graded concentrations of topcoat) was also achieved in this work to provide the required adhesion between the substrate and the coating. Combination of an appropriate bond coat and a functional top coat provided the present thermal degradation resistant coating for cutting tools and die-casting applications. Laboratory level performance tests and industrial level application tests by partner companies (Beta Site Testing) were used for the development of these coatings.

  9. A review on mechanical properties of magnesium based nano composites

    Science.gov (United States)

    Tarafder, Nilanjan; Prasad, M. Lakshmi Vara

    2018-04-01

    A review was done on Magnesium (Mg) based composite materials reinforced with different nano particles such as TiO2, Cu, Y2O3, SiC, ZrO2 and Al2O3. TiO2 and Al2O3 nanoparticles were synthesised by melt deposition process. Cu, Y2O3, SiC and ZrO2 nanoparticles were synthesised by powder metallurgy process. Composite microstructural characteristics shows that the nano-size reinforcements are uniformly distributed in the composite matrix and also minimum porosity with solid interfacial integrity. The mechanical properties showed yield strength improvement by 0.2 percentage and Ultimate tensile strength (UTS) was also improved for all the nano-particles. But UTS was adversely affected with TiO2 reinforcement while ductility was increased. With Cu reinforcement elastic modulus, hardness and fracture resistance increased and improved the co-efficient of thermal expansion (CTE) of Mg based matrix. By Y2O3 reinforcement hardness, fracture resistance was improved and ductility reached maximum by 0.22 volume percentage of Y2O3 and decreased with succeeding increase in Y2O3 reinforcement. The readings exposed that mechanical properties were gathered from the composite comprising 2.0 weight percentage of Y2O3. Ductility and fracture resistance increased with ZrO2 reinforcement in Mg matrix. Using Al2O3 as reinforcement in Mg composite matrix hardness, elastic modulus and ductility was increased but porosity reduced with well interfacial integrity. Dissipation of energy in the form of damping capacity was resolved by classical vibration theory. The result showed that an increasing up to 0.4 volume percentage alumina content increases the damping capacity up to 34 percent. In another sample, addition of 2 weight percentage nano-Al2O3 particles showed big possibility in reducing CTE from 27.9-25.9×10-6 K-1 in Magnesium, tensile and yield strength amplified by 40MPa. In another test, Mg/1.1Al2O3 nanocomposite was manufactured by solidification process followed by hot extrusion

  10. Synthesis and characterization of new polyimide/organo clay nano composites containing benzophenone moieties in the main chain

    International Nuclear Information System (INIS)

    Faghihi, K.; Ashouri, M.; Feyzi, A.

    2013-01-01

    A series of nano composites consist of organic polyimide and organo-modified clay content varying from 0 to 5 wt %, were successfully prepared by in situ polymerization. Polyimide used as a matrix of nano composite was prepared through the reaction of 1,4-bis [4-aminophenoxy] butane and 3,3,4,4-benzophenone tetra carboxylic dianhydride in N,N-dimethylacetamide (Dmac). The resulting nano composite films were characterized by Ft-IR spectroscopy, X-ray diffraction, scanning electron microscopy and thermogravimetric analysis. (Author)

  11. Synthesis and characterization of new polyimide/organo clay nano composites containing benzophenone moieties in the main chain

    Energy Technology Data Exchange (ETDEWEB)

    Faghihi, K.; Ashouri, M.; Feyzi, A., E-mail: k-faghihi@araku.ac.ir [Arak University, Faculty of Science, Organic Polymer Chemistry Research Laboratory, 38158-879 Arak (Iran, Islamic Republic of)

    2013-08-01

    A series of nano composites consist of organic polyimide and organo-modified clay content varying from 0 to 5 wt %, were successfully prepared by in situ polymerization. Polyimide used as a matrix of nano composite was prepared through the reaction of 1,4-bis [4-aminophenoxy] butane and 3,3,4,4-benzophenone tetra carboxylic dianhydride in N,N-dimethylacetamide (Dmac). The resulting nano composite films were characterized by Ft-IR spectroscopy, X-ray diffraction, scanning electron microscopy and thermogravimetric analysis. (Author)

  12. [Study on biocompatibility of hydroxyapatite/high density polyethylene (HA/HDPE) nano-composites artificial ossicle].

    Science.gov (United States)

    Wang, Guohui; Zhu, Shaihong; Tan, Guolin; Zhou, Kechao; Huang, Suping; Zhao, Yanzhong; Li, Zhiyou; Huang, Boyun

    2008-06-01

    This study was aimed to evaluate the biocompatibility of Hydroxyapatite/High density polyethylene (HA/ HDPE) nano-composites artificial ossicle. The percentage of S-period cells were detected by flow cytometry after L929 cells being incubated with extraction of the HA/HDPE nano-composites; the titanium materials for clinical application served as the contrast. In addition, both materials were implanted in animals and the histopathological evaluations were conducted. There were no statistically significant differences between the two groups (P >0.05). The results demonstrated that the HA/HDPE nano-composite artificial ossicle made by our laboratory is of a good biocompatibility and clinical application outlook.

  13. Influence of Compatibilizer and Processing Conditions on Morphology, Mechanical Properties, and Deformation Mechanism of PP/Clay Nano composite

    International Nuclear Information System (INIS)

    Akbari, B.; Bagheri, R.

    2012-01-01

    Polypropylene/montmorillonite nano composite was prepared by melt intercalation method using a twin-screw extruder with starve feeding system in this paper. The effects of compatibilizer, extruder rotor speed and feeding rate on properties of nano composite were investigated. Structure, tensile, and impact properties and deformation mechanism of the compounds were studied. For investigation of structure and deformation mechanisms, X-ray diffraction (XRD) and transmission optical microscopy (TOM) techniques were utilized, respectively. The results illustrate that introduction of the compatibilizer and also variation of the processing conditions affect structure and mechanical properties of nano composite.

  14. Optical properties study of nano-composite filled D shape photonic crystal fibre

    Science.gov (United States)

    Udaiyakumar, R.; Mohamed Junaid, K. A.; Janani, T.; Maheswar, R.; Yupapin, P.; Amiri, I. S.

    2018-06-01

    With the nano-composite materials gaining momentum in the optical field, a new nano-composite filled D shape Photonic Crystal Fiber (PCF) is designed and the various optical properties are investigated with help of Finite Element Method. In the proposed structure the D-shape PCF is made up of silica with embedded silver nanoparticles and air holes are distributed along the fibre. The designed fibre shows various optical properties such as dispersion, birefringence, beat length and loss with respect to wavelength and compared with different filling factor like 0.1, 0.3 and 0.5. From our estimation and comparative analysis, it has been proved that the fibre loss has been decreased with increasing filling factor. Further this also showed flat dispersion at maximum filling factor.

  15. Conductive nano composites based on cellulose nano fiber coated poly aniline via in situ polymerization

    International Nuclear Information System (INIS)

    Silva, Michael J. da; Sanches, Alex O.; Malmonge, Luiz F.; Malmonge, Jose A.; Medeiros, Eliton S. de; Rosa, Morsyleide F.

    2011-01-01

    Cellulose nano fiber (CNF) was extracted by acid hydrolysis from cotton microfibril and nano composites of CNF/PANI-DBSA were obtained by in situ polymerization of aniline onto CNF. The ratios between DBSA/aniline and aniline/oxidant were varied and the nano composites were characterized by four probes direct current (dc) electrical conductivity, ultraviolet-visible (UV-Vis-NIR) and FTIR spectroscopy and X-ray diffraction (XRD). Electrical conductive about ∼10 -1 S/cm was research and was independent of DBSA/aniline molar ratio between 2-4 and the aniline/oxidant molar ratio between 1-5. X-ray patterns of the samples show crystalline peaks characteristic of cellulose I. The FTIR spectra confirmed the presence of PANI and CNF in all samples. (author)

  16. Preparation and performance of ZnO/Polyaniline nano-composite for supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Yu, S.P.; Chang, X.C.; Wang, Z.M.; Han, K.F.; Zhu, H. [Beijing Univ. of Chemical Technology, Beijing (China). School of Science

    2010-07-01

    Supercapacitors combine the advantages of traditional capacitors and batteries. In this study, a zinc oxide (ZnO-PANI) nano-composite material was fabricated in order to investigate its behaviour in a supercapacitor application. The ZnO nano-powder was synthesized using the sol-gel method. An inverted emulsion polymerization method was then used to prepare the ZnO/PANI nanocomposite. X-ray diffraction (XRD) analyses demonstrated that the prepared ZnO had a hexagonal structure. The ZnO/PANI composite electrode was prepared. Electrochemical impedance spectroscopy (EIS) analyses indicated that the nano-composite material functioned well as an electrode. The highest capacitance rating achieved by the electrode was 31.82 F per g. 6 refs., 4 figs.

  17. Morphology of Poly lactide/Polycaprolactone (PLA/PCL) Nano composite by Scanning Electron Microscopy (SEM)

    International Nuclear Information System (INIS)

    Siti Zulaiha Hairaldin; Wan Md Zin Wan Yunus; Norazowa Ibrahim

    2011-01-01

    In this study, Octadecylamine Modified Montmorillonites (ODAMMT) were used to prepare Poly lactide/ Polycaprolactone (PLA/ PCL) nano composites. PLA and PCL mix in 90:10 ratios, using an internal mixer by melt blending technique. The other sample was blend with Natrium Montmorillonite (NaMMT) and Octadecylamine Modified Montmorillonite (ODA-MMT) to produce PLA/ PCL-NaMMT and PLA/ PCL ODAMMT. To characterize the polymer nano composites, X-ray diffraction (XRD), FTIR and SEM analysis were conducted. Comparison of morphology were made up between PLA/ PCL, PLA/ PCL with presence of 7 % of Na-MMT and 7 % ODA-MMT respectively based on SEM micrograph by calculate the number-average diameter. (author)

  18. Finite Element Model Characterization Of Nano-Composite Thermal And Environmental Barrier Coatings

    Science.gov (United States)

    Yamada, Yoshiki; Zhu, Dongming

    2011-01-01

    Thermal and environmental barrier coatings have been applied for protecting Si based ceramic matrix composite components from high temperature environment in advanced gas turbine engines. It has been found that the delamination and lifetime of T/EBC systems generally depend on the initiation and propagation of surface cracks induced by the axial mechanical load in addition to severe thermal loads. In order to prevent T/EBC systems from surface cracking and subsequent delamination due to mechanical and thermal stresses, T/EBC systems reinforced with nano-composite architectures have showed promise to improve mechanical properties and provide a potential crack shielding mechanism such as crack bridging. In this study, a finite element model (FEM) was established to understand the potential beneficial effects of nano-composites systems such as SiC nanotube-reinforced oxide T/EBC systems.

  19. Novel Nano-Composite Catalysts for Renewable Energy Storage Applications

    Science.gov (United States)

    Devaguptapu, Surya Vamsi

    Spinel NiCo2O4 catalysts are considered the promising precious metal-free catalyst for oxygen reactions. Significant efforts are mainly explore optimal chemical doping and substituent to tune its electronic structures for enhanced performance. Here, we focuses on morphology control and determine the morphology-dependent activity for bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In particular, three types of spinel NiCo2O4 were prepared using temple-free, SiO 2 hard template, and Pluronic-123 soft template hydrothermal methods, showing significantly different morphologies, respectively. In particular, template-free method yield dense structures. Sold-template method assists the formation of porous and hollow structures. Importantly, the soft template is effective to prepare a unique nanoflower morphology containing abundant rose petal (needle) like structures. The effect of the utilization of templates, both soft and hard as well as a template free synthesis on the morphology as well as the activity and stability of the final catalyst is investigated. Compared to others, the nanoflower-like NiCo2O4 exhibited the highest bifunctional catalytic activity simultaneously for ORR and OER, likely due to the facile absorption of oxygen molecules on increased surface areas with efficient mass transfer. The nanoflower NiCo2O 4 also exhibited an onset and half-wave potentials of 0.94 and 0.82 V for the ORR in alkaline media. Although it is still inferior to state of the art Pt, the new type of spinel NiCo2O4 catalyst represents the best activity compared to reported carbon-free oxides. Meanwhile, OER activity and stability were achieved with an onset potential of 1.48 V generating a current density of 14 mA/cm2 at 1.6 V. The OER activity does not declined after 10,000 potential cycles demonstrating excellent stability, which is superior to the benchmark of Ir for the OER. This work provides an effective solution to enhance catalytic activity

  20. Marginal and internal fit of nano-composite CAD/CAM restorations

    Directory of Open Access Journals (Sweden)

    So-Hyun Park

    2016-02-01

    Full Text Available Objectives The purpose of this study was to compare the marginal and internal fit of nano-composite CAD-CAM restorations. Materials and Methods A full veneer crown and an mesio-occluso-distal (MOD inlay cavity, which were prepared on extracted human molars, were used as templates of epoxy resin replicas. The prepared teeth were scanned and CAD-CAM restorations were milled using Lava Ultimate (LU and experimental nano-composite CAD/CAM blocks (EB under the same milling parameters. To assess the marginal and internal fit, the restorations were cemented to replicas and were embedded in an acrylic mold for sectioning at 0.5 mm intervals. The measured gap data were pooled according to the block types and measuring points for statistical analysis. Results Both the block type and measuring point significantly affected gap values, and their interaction was significant (p = 0.000. In crowns and inlays made from the two blocks, gap values were significantly larger in the occlusal area than in the axial area, while gap values in the marginal area were smallest (p < 0.001. Among the blocks, the restorations milled from EB had a significantly larger gap at all measuring points than those milled from LU (p = 0.000. Conclusions The marginal and internal gaps of the two nano-composite CAD/CAM blocks differed according to the measuring points. Among the internal area of the two nano-composite CAD/CAM restorations, occlusal gap data were significantly larger than axial gap data. The EB crowns and inlays had significantly larger gaps than LU restorations.

  1. Removal of light petroleum hydrocarbons from water sources using polypropylene and titanium dioxide nano-composite

    Directory of Open Access Journals (Sweden)

    H. Karyab

    2016-08-01

    Full Text Available Background: Petroleum hydrocarbons are the most important pollutants which threat human health and aquatics. Adsorbents are one of the common equipment in water pollution management; however, their applications have been associated with limitations. Objective: To evaluate the potential of polypropylene/titanium dioxide Nano-composite in adsorption of light petroleum hydrocarbons from water sources. Methods: This experimental study was conducted at school of health, Qazvin University of Medical Sciences in 2014-15. Activation of polypropylene fibers, with 1 cm length and 300 microns diameters, was achieved with wet heating. To synthesize of nano-composite the fibers were coated with nano-titanium dioxide with 20 nm diameter. The sonication was performed at 26 kHz and 100 W of power in 40ºc. The morphology of the fractured surfaces of impact specimens was examined by FESEM. The adsorption rate of petrol and gasoline, as surrogate of TPH, was evaluated in different retention time within polyamide mesh aperture diameter of 250 nm. Average of TPH adsorbing, per unit weight of adsorbent, were analyzed with analysis of variance and Scheffe post hoc tests. Findings: The FESEM micrographs showed that the dispersion of the nano-Tio2 particles was relatively good and only few aggregations exist. The maximum adsorption capacity of petrol and gasoline was obtained in 30 minute. The adsorption rate of gasoline was 6.49±0.10 g/g and oil was 7.01±0.13 g/g. Conclusion: According to the results and in comparison with commercial imported adsorbents, the synthesized Nano-composite had favorable performance. The results show that the polypropylene/Tio2 Nano-composite can be used effectively in light petroleum hydrocarbons removal from polluted water sources.

  2. BACTERICIDE IMPACT OF POLYMER-STABILIZED MULTI-FUNCTIONAL NANO-COMPOSITES

    OpenAIRE

    Graskova I.A.; М.А. Zhivet’yev; G.B. Borovskii; B.G. Sukhov

    2012-01-01

    Synthesis on the basis of natural matrices in order to acquire products with the desired properties is one of the promising trends of modern science. Using polysaccharides as a matrix allowed to generate derivatives with diverse structures and new properties. Growing interest towards anti-microbe effect of selenium-containing nano-composites is induced by the phenomenon of antibiotic-resistance of contemporary pathogenic microorganisms.Clavibacter genus bacteria are the most significant and w...

  3. Performance evaluation on solar still integrated with nano-composite phase change materials

    International Nuclear Information System (INIS)

    Rajasekhar, G.; Eswaramoorthy, M.

    2015-01-01

    This paper communicates the performance evaluation of single slope solar still integrated with nano-composite phase change materials and compare with the experimental results of with and without phase change materials. A solar still with 1 m"2 surface area is developed with non-selective coating of absorber sheet with the provision of thermal energy storage materials. The solar still is tested on typical days with and without thermal energy storage materials. It is found that from the experimental studies that nano-materials (Al_2O_3) dispersed in paraffin wax is giving better cumulative yield of distillate than paraffin wax alone and without paraffin wax thermal storage. The daily efficiency of the solar still is computed for solar still with nano-composite phase change materials is 45% and solar still paraffin wax alone thermal storage is 40% and solar still without any thermal storage is 38%. It is concluded from the experimental studies; solar still integrated with nano-composite phase change materials gives better performance than with and without phase change material alone. (authors)

  4. Oxidation Behavior of AlN/h-BN Nano Composites at High Temperature

    International Nuclear Information System (INIS)

    Jin Haiyun; Huang Yinmao; Feng Dawei; He Bo; Yang Jianfeng

    2011-01-01

    Both AlN/ nano h-BN composites and AlN/ micro h-BN composites were fabricated. The high temperature oxidation behaviors were investigated at 1000deg. C and 1300deg. C using a cycle-oxidation method. The results showed that there were little changes of both nano composites and monolithic AlN ceramic at temperature of 1000deg. C. And at 1300deg. C, the oxidation dynamics curve of composites could be divided into two courses: a slowly weight increase and a rapid weight decrease, but the oxidation behavior of nano composites was better than micro composites. It was due to that the uniform distribution of oxidation production (Al 18 B 4 O 33 ) surround the AlN grains in nano composites and the oxidation proceeding was retarded. The XRD analysis and SEM observations showed that there was no BN remained in the composites surface after 1300deg. C oxidation and the micropores remain due to the vaporizing of B 2 O 3 oxidized by BN.

  5. Polyurethane/organo clay nano composite materials via in-situ polymerization

    International Nuclear Information System (INIS)

    Rehab, A.; Agag, T; Akelah, A.; Shalaby, N.

    2005-01-01

    Polyurethane/organo clay nano composites have been synthesized via in situ polymerization. The organo clay firstly prepared by intercalation of lyamine or amino lauric acid into montmorillonite-clay (MMT) through ion exchange process. The syntheses of polyurethane/organo clay hybrid films containing different ratio of clay were carried out by swelling the organo clay, into diol and diamine or into different kinds of diols, followed by addition of diisocyanate. The nano composites with dispersed structure of MMT was obtained as evidence by scanning electron microscope and x-ray diffraction. X-ray analysis showed that the d-spacing increased to more than 44A since there is no peaks corresponding to do spacing in organo clay with all the ratios (1, 5, 10, 20%). Also, SEM results confirm the dispersion of nanometer silicate layers in the polyurethane matrix. This indicated that the clay was completely exfoliated and homogeneous dispersion in the polyurethane matrix. Also, it was found that the presence of organo clay leads to improvement the mechanical properties. Since, the tensile strength increased with increasing the organo clay contents to 20% by the ratio 194% in compared to the 1H: with 0% organo clay. Also, the elongation is a decreases with increasing the organo clay contents. The results shown the tensile strength of PU/SMA/ALA-MMT nano composites is high by 6-7 times than the corresponding to PU/Tvr-MMT

  6. Characterization of dispersion of a nano composites PP/TiO2 non modified

    International Nuclear Information System (INIS)

    Soares, Igor L.; Tavares, Maria I.B.; Silva, Vanessa A. da; Legramanti, Cintia; Luetkmeyer, Leandro

    2011-01-01

    Polymeric nano composites are composite materials where an inorganic particle, which has a dimension in the nanometer range, is dispersed in a polymer matrix. Nano composites, using polypropylene (PP) as matrix polymer and titanium dioxide (TiO 2 ) as filler, have great versatility in marketing applications, this factor is inherent in the PP and the inherent ability photo degraded TiO 2 particles. This combination can lead to a widely used material and a degradation time after discharge reduced, there by becoming, a residue of low environmental impact. This study aimed to evaluate the dispersion and particle distribution of TiO 2 , non modified, in PP matrix, using the process of preparation by melt extrusion pathway and characterization of the materials obtained: on the molecular dynamics, using low field NMR solid state, measures the relaxation time spin-network (T 1 H); morphology using XRD technique, and thermal analysis technique with the TGA of pure PP and nano composites PP/TiO 2 . (author)

  7. Are nano-composites and nano-ionomers suitable for orthodontic bracket bonding?

    Science.gov (United States)

    Uysal, Tancan; Yagci, Ahmet; Uysal, Banu; Akdogan, Gülsen

    2010-02-01

    The aim of this study was to test nano-composite (Filtek Supreme Plus Universal) and a newly introduced nano-ionomer (Ketac N100 Light Curing Nano-Ionomer) restorative to determine their shear bond strength (SBS) and failure site locations in comparison with a conventional light-cure orthodontic bonding adhesive (Transbond XT). Sixty freshly extracted human maxillary premolar teeth were arbitrarily divided into three equal groups. The brackets were bonded to the teeth in each group with different composites, according to the manufacturers' instructions. The SBS values of the brackets were recorded in Megapascals (MPa) using a universal testing machine. Adhesive remnant index scores were determined after failure of the brackets. The data were analysed using analysis of variance, Tukey honestly significant difference, and chi-square tests. The results demonstrated that group 1 (Transbond XT, mean: 12.60 +/- 4.48 MPa) had a higher SBS than that of group 2 (nano-composite, mean: 8.33 +/- 5.16 MPa; P nano-ionomer, mean: 6.14 +/- 2.12 MPa; P Nano-composites and nano-ionomers may be suitable for bonding since they fulfil the previously suggested SBS ranges for clinical acceptability, but they are inferior to a conventional orthodontic composite.

  8. BACTERICIDE IMPACT OF POLYMER-STABILIZED MULTI-FUNCTIONAL NANO-COMPOSITES

    Directory of Open Access Journals (Sweden)

    Graskova I.A.

    2012-08-01

    Full Text Available Synthesis on the basis of natural matrices in order to acquire products with the desired properties is one of the promising trends of modern science. Using polysaccharides as a matrix allowed to generate derivatives with diverse structures and new properties. Growing interest towards anti-microbe effect of selenium-containing nano-composites is induced by the phenomenon of antibiotic-resistance of contemporary pathogenic microorganisms.Clavibacter genus bacteria are the most significant and widely spread among gram-positive bacteria. Bacteria cells are static pleimorphous rods, normally singular, sometimes coupled or joined in short chains, strict anaerobes in need of certain growth factors, non-sporogenous. Clavibacter michiganensis subsp. sepedonicus cause potato ring rot. At the tuber slice the damage is shaped as a ring; growing bacteria are accumulated in the conducting vessels causing their occlusion and therefore gradual withering of leaves and stem. This disease is distributed at all the continents including Australia. Harvest loss through ring rot damage may reach 10-45%.Our work was aimed at the study of complex interaction between microbe cultivar and selenium-based nanocomposites. Bacterial strain Аs1405 was acquired from the All-Russia collection of microorganisms, IMBP RAS. This genus is not included in the classification of pathogenic microorganisms by pathogenic groups of Sanitary-Epidemiological Rules SP 1.3.2322-08. The present study was focused on characteristics of the acquired strain.Fluorescent and electronic-scanning microscope was used to acquire photographs of bacterial cells. Pathogen was identified by PCR-analysis, which confirmed the presence of DNA of desired size. The extracted DNA was sequenced with the sequenced sequence added to Gen Bank under the number HQ394204. Cellulolytic and phytotoxic activity of this strain was determined.Chemistry Institute named A.E. Favorsky provided water-soluble nano-composites

  9. Y2O3-MgO Nano-Composite Synthesized by Plasma Spraying and Thermal Decomposition of Solution Precursors

    Science.gov (United States)

    Muoto, Chigozie Kenechukwu

    This research aims to identify the key feedstock characteristics and processing conditions to produce Y2O3-MgO composite coatings with high density and hardness using solution precursor plasma spray (SPPS) and suspension plasma spray (SPS) processes, and also, to explore the phenomena involved in the production of homogenized nano-composite powders of this material system by thermal decomposition of solution precursor mixtures. The material system would find potential application in the fabrication of components for optical applications such as transparent windows. It was shown that a lack of major endothermic events during precursor decomposition and the resultant formation of highly dense particles upon pyrolysis are critical precursor characteristics for the deposition of dense and hard Y2O3-MgO coatings by SPPS. Using these principles, a new Y2O3-MgO precursor solution was developed, which yielded a coating with Vickers hardness of 560 Hv. This was a considerable improvement over the hardness of the coatings obtained using conventional solution precursors, which was as low as 110 Hv. In the thermal decomposition synthesis process, binary solution precursor mixtures of: yttrium nitrate (Y[n]) or yttrium acetate (Y[a]), with magnesium nitrate (Mg[n]) or magnesium acetate (Mg[a]) were used in order to study the effects of precursor chemistry on the structural characteristics of the resultant Y2O3-MgO powders. The phase domains were coarse and distributed rather inhomogeneously in the materials obtained from the Y[n]Mg[n] and Y[a]Mg[a] mixtures; finer and more homogeneously-distributed phase domains were obtained for ceramics produced from the Y[a]Mg[n] and Y[n]Mg[a] mixtures. It was established that these phenomena were related to the thermal characteristics for the decomposition of the precursors and their effect on phase separation during oxide crystallization. Addition of ammonium acetate to the Y[n[Mg[n] mixture changed the endothermic process to exothermic

  10. Polymer-layered silicate nano composite by UV-radiation curing: an original synthesis

    International Nuclear Information System (INIS)

    Keller, L.; Decker, C.; Zahouily, K.; Miehe-Brendle, J.; Le Meins, J.M.

    2004-01-01

    Full text.Because of the many hopes which they raise, the nano composite materials are the subject of an increasing number of scientific publications. Indeed, the intimate association of a polymer matrix and silicate nano-platelets leads to the formation of materials having mechanical and barriers properties improved (fire, gas, humidity...). A literature survey shows that these materials are generally produced by a thermal polymerization, which presents two major disadvantages: the use of organic solvents and a great consumption of energy. To overcome such limitations, photo initiated polymerization was chosen to synthesize nano composite materials. By this technology, called UV radiation curing, a solvent-free resin is transformed within seconds into a solid polymer upon exposure to UV-radiation at ambient temperature. The principal objective of this study was to develop photopolymerizable systems with clay particles having a layer structure (phyllosilicates). The clay mineral was made organophilic by treatment with an alkylammonium salt to allow the acrylate resin to penetrate into the expanded galleries. A morphological characterization of the materials obtained was carried out by X-rays diffraction and electronic microscopy transmission. The polymerization of the various resins under the UV exposure was followed in situ by using the real-time infrared spectroscopy (RT-FTIR) and attenuated total reflection (ATR). The results obtained show that the presence of the organo clay does not modify much the polymerization kinetics. The nano composite material thus obtained is transparent, insoluble in the organic solvents and presents improved mechanical properties, compared to the neat resin and the micro composite, for a load factor ranging between 2 and 5%wt. The addition of nanoparticles also makes it possible to reduce efficiently the brightness of coatings UV and finally confers to this material barriers properties higher than that of the photo crosslinked

  11. Exergy analysis of the solar still integrated nano composite phase change materials

    International Nuclear Information System (INIS)

    Methre, V.K.; Eswaramoorthy, M.

    2015-01-01

    This paper communicates the exergy analysis of solar still integrated with nano composite phase change materials for design and operating parameters. Al_2O_3 nano materials (50 nm) is dispersed by weight ratio in paraffin wax at melting state and its thermophysical properties are evaluated using developed correlation. Exergy balance equation for basin liner, thermal energy storage, glass cover and saline water is developed and exergy efficiency is analysed. It is found that exergy efficiency is improved by higher weight ratio of Al_2O_3 nano materials with paraffin wax alone. (author)

  12. Digital laser printing of metal/metal-oxide nano-composites with tunable electrical properties

    International Nuclear Information System (INIS)

    Zenou, M; Kotler, Z; Sa’ar, A

    2016-01-01

    We study the electrical properties of aluminum structures printed by the laser forward transfer of molten, femtoliter droplets in air. The resulting printed material is an aluminum/aluminum-oxide nano-composite. By controlling the printing conditions, and thereby the droplet volume, its jetting velocity and duration, it is possible to tune the electrical resistivity to a large extent. The material resistivity depends on the degree of oxidation which takes place during jetting and on the formation of electrical contact points as molten droplets impact the substrate. Evidence for these processes is provided by FIB cross sections of printed structures. (paper)

  13. Study of rheological, viscoelastic and vulcanization behavior of sponge EPDM/NR blended nano- composites

    International Nuclear Information System (INIS)

    Bashir, M Arshad; Shahid, M; Ahmed, Riaz; Yahya, A G

    2014-01-01

    In this research paper the effect of blending ratio of natural rubber (NR) with Ethylene Propylene Diene Monomer (EPDM) were investigated. Different samples of EPDM/NR ratio were prepared to study the variation of NR in EPDM on rheology, curing characteristics, tangent δ, and viscosity variation during vulcanization of sponge nano composites.The main aim of present research is to develop elastomeric based sponge composites with the blending ratio of base elastomers along with the carbon nano particles for high energy absorbing and damping applications. The curing characteristics, rheology and viscoelastic nature of the composite is remarkably influenced with the progressive blending ratio of the base elastomeric matrix

  14. Study of rheological, viscoelastic and vulcanization behavior of sponge EPDM/NR blended nano-composites

    International Nuclear Information System (INIS)

    Bashir, M. A.; Shahid, M.; Ahmed, R.; Yahya, A. G.

    2013-01-01

    In this research paper the effect of blending ratio of natural rubber (NR) with Ethylene Propylene Diene Monomer (EPDM) were investigated. Different samples of EPDM/NR ratio were prepared to study the variation of NR in EPDM on rheology, curing characteristics, tangent d, and viscosity variation during vulcanization of sponge nano composites. The main aim of present research is to develop elastomeric based sponge composites with the blending ratio of base elastomers along with the carbon nano particles for high energy absorbing and damping applications. The curing characteristics, rheology and viscoelastic nature of the composite is remarkably influenced with the progressive blending ratio of the base elastomeric matrix. (author)

  15. Electrochemical Synthesis of Graphene/MnO2 Nano-Composite for Application to Supercapacitor Electrode.

    Science.gov (United States)

    Jeong, Kwang Ho; Lee, Hyeon Jeong; Simpson, Michael F; Jeong, Mun

    2016-05-01

    Graphene/MnO2 nano-composite was electrochemically synthesized for application to an electrode material for electrochemical supercapacitors. The nanosized needle-like MnO2 was obtained by use of a graphene substrate. The prepared composite exhibited an ideal supercapacitive behavior. A capacitance retention of 94% was achieved with a 4 h deposition time (an initial capacitance of 574 mF/cm2 at a scan rate of 20 mV/s) and the retention declined with further deposition time. The results demonstrate enhanced contact between the electrode and electrolyte and improved power density as an electrochemical capacitor.

  16. Fracture toughness of epoxy/multi-walled carbon nanotube nano-composites under bending and shear loading conditions

    International Nuclear Information System (INIS)

    Ayatollahi, M.R.; Shadlou, S.; Shokrieh, M.M.

    2011-01-01

    Research highlights: → Mode I and mode II fracture tests were conducted on epoxy/MWCNT nano-composites. → Addition of MWCNT to epoxy increased both K Ic and K IIc of nano-composites. → The improvement in K IIc was more pronounced than in K Ic . → Mode I and mode II fracture surfaces were studied by scanning electron microscopy. -- Abstract: The effects of multi-walled carbon nanotubes (MWCNTs) on the mechanical properties of epoxy/MWCNT nano-composites were studied with emphasis on fracture toughness under bending and shear loading conditions. Several finite element (FE) analyses were performed to determine appropriate shear loading boundary conditions for a single-edge notch bend specimen (SENB) and an equation was derived for calculating the shear loading fracture toughness from the fracture load. It was seen that the increase in fracture toughness of nano-composite depends on the type of loading. That is to say, the presence of MWCNTs had a greater effect on fracture toughness of nano-composites under shear loading compared with normal loading. To study the fracture mechanisms, several scanning electron microscopy (SEM) pictures were taken from the fracture surfaces. A correlation was found between the characteristics of fracture surface and the mechanical behaviors observed in the fracture tests.

  17. Impact of Surface Modification and Nanoparticle on Sisal Fiber Reinforced Polypropylene Nano composites

    International Nuclear Information System (INIS)

    Ibrahim, I. D.; Jamiru, T.; Sadiku, E. R.; Agwuncha, S. Ch.; Kupolati, W. K.

    2016-01-01

    The use of plant fibers, polymer, and nanoparticles for composite has gained global attention, especially in the packaging, automobile, aviation, building, and construction industries. Nano composites materials are currently in use as a replacement for traditional materials due to their superior properties, such as high strength-to-weight ratio, cost effectiveness, and environmental friendliness. Sisal fiber (SF) was treated with 5% NaOH for 2 hours at 70"°C. A mixed blend of sisal fiber and recycled polypropylene (rPP) was produced at four different fiber loadings: 10, 20, 30, and 40 wt.%, while nano clay was added at 1, 3, and 5 wt.%. Maleic anhydride grafted polypropylene (MAPP) was used as the compatibilizer for all composites prepared except the untreated sisal fibers. The characterization results showed that the fiber treatment, addition of MAPP, and nano clay improved the mechanical properties and thermal stability and reduced water absorption of the SF/rPP nano composites. The tensile strength, tensile modulus, and impact strength increased by 32.80, 37.62, and 5.48%, respectively, when compared to the untreated SF/rPP composites. Water absorption was reduced due to the treatment of fiber and the incorporation of MAPP and nano clay.

  18. Radiation induced synthesis of conducting polymers and their metal nano-composites

    International Nuclear Information System (INIS)

    Cui, Zhenpeng

    2017-01-01

    The aim of the present work is to demonstrate the versatility of the gamma (γ)-rays based radiolytic method and to extend our methodology to the synthesis of various conducting polymers (CPs) in water in different experimental conditions. Poly(3,4-ethylenedioxy-thiophene) (PEDOT) and poly-pyrrole (PPy) conjugated polymers were successfully prepared and characterized in solution and after deposition by complementary spectroscopic and microscopic techniques. Also their thermal stability and their electrical conductivity were studied and compared with those of CPs prepared by conventional methods. The influence of the nature of radiation-induced oxidizing radicals, of the ionic strength, of the medium, of the pH, of the presence of surfactant-based soft templates on the growth mechanism, on the efficiency of polymerization, on the morphology of the obtained CPs as well as on their absorption and conducting properties was checked. Also, the radiolytic method was extend to the synthesis of CPs/noble metal nano-composites. Different preparation methodologies were developed based on two-step method and one-pot method, by using oxidation route or reduction route. Our new radiolytic strategy described and extended in this manuscript opens the way for the preparation of different kinds of CPs and CPs nano-composites not only in aqueous solutions but also in various environments foreshadowing many promising applications.. (author)

  19. Micro/nano composited tungsten material and its high thermal loading behavior

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Jinglian, E-mail: fjl@csu.edu.cn; Han, Yong; Li, Pengfei; Sun, Zhiyu; Zhou, Qiang

    2014-12-15

    Tungsten (W) is considered as promising candidate material for plasma facing components (PFCs) in future fusion reactors attributing to its many excellent properties. Current commercial pure tungsten material in accordance with the ITER specification can well fulfil the performance requirements, however, it has defects such as coarse grains, high ductile–brittle transition temperature (DBTT) and relatively low recrystallization temperature compared with its using temperature, which cannot meet the harsh wall loading requirement of future fusion reactor. Grain refinement has been reported to be effective in improving the thermophysical and mechanical properties of W. In this work, rare earth oxide (Y{sub 2}O{sub 3}/La{sub 2}O{sub 3}) and carbides (TiC/ZrC) were used as dispersion phases to refine W grains, and micro/nano composite technology with a process of “sol gel – heterogeneous precipitation – spray drying – hydrogen reduction – ordinary consolidation sintering” was invented to introduce these second-phase particles uniformly dispersed into W grains and grain-boundaries. Via this technology, fine-grain W materials with near-full density and relatively high mechanical properties compared with traditional pure W material were manufactured. Preliminary transient high-heat flux tests were performed to evaluate the thermal response under plasma disruption conditions, and the results show that the W materials prepared by micro/nano composite technology can endure high-heat flux of 200 MW/m{sup 2} (5 ms)

  20. Tailored sPP/Silica Nano composite for Eco friendly Insulation of Extruded HVDC Cable

    International Nuclear Information System (INIS)

    Dang, B.; He, J.; Hu, J.; Zhou, Y.

    2015-01-01

    Cross-linked polyethylene (XLPE) is a thermosetting material that cannot be recycled at the end of its lifetime. This study investigated the potential of syndiotactic polypropylene (sPP)/silica as an eco friendly extruded insulation system for HVDC cables. We investigated the morphology, Fourier transform infrared, and thermal, thermomechanical, and electrical behaviors of sPP modified with 0.5-3% nano silica. We found that the silica/sPP nano composite without cross-linking offered a suitable mechanical modulus at room temperature and sufficient intensity at high temperatures, and adding nano silica modified by a silane coupling agent to the sPP resulted in significant DC resistivity and space charge improvement. The optimal nano silica content in the sPP was determined by balancing the mechanical and thermomechanical characteristics and the DC resistivity. The sPP/silica nano composite reported here shows great potential as a candidate insulation material for future eco friendly extruded HVDC cables.

  1. Fabrication of Surface Level Cu/Si Cp Nano composites by Friction Stir Processing Route

    International Nuclear Information System (INIS)

    Srinivasan, R. C.; Karunanithi, M.

    2015-01-01

    Friction stir processing (FSP) technique has been successfully employed as low energy consumption route to prepare copper based surface level nano composites reinforced with nano sized silicon carbide particles (Si Cp). The effect of FSP parameters such as tool rotational speed, processing speed, and tool tilt angle on microstructure and microhardness was investigated. Single pass FSP was performed based on Box-Behnken design at three factors in three levels. A cluster of blind holes 2 mm in diameter and 3 mm in depth was used as particulate deposition technique in order to reduce the agglomeration problem during composite fabrication. K-type thermocouples were used to measure temperature histories during FSP. The results suggest that the heat generation during FSP plays a significant role in deciding the microstructure and microhardness of the surface composites. Microstructural observations revealed a uniform dispersion of nano sized Si Cp without any agglomeration problem and well bonded with copper matrix at different process parameter combinations. X-ray diffraction study shows that no intermetallic compound was produced after processing. The microhardness of nano composites was remarkably enhanced and about 95% more than that of copper matrix

  2. Lithium-doped hydroxyapatite nano-composites: Synthesis, characterization, gamma attenuation coefficient and dielectric properties

    Science.gov (United States)

    Badran, H.; Yahia, I. S.; Hamdy, Mohamed S.; Awwad, N. S.

    2017-01-01

    Lithium-hydroxyapatite (0, 1, 5, 10, 20, 30 and 40 wt% Li-HAp) nano-composites were synthesized by sol-gel technique followed by microwave-hydrothermal treatment. The composites were characterized by X-ray diffraction (XRD), Field emission scanning electron microscope (FE-SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared (FTIR) and Raman techniques. Gamma attenuation coefficient and the dielectric properties for all composites were investigated. The crystallinity degree of Li-doped HAp was higher than that of un-doped HAp. Gamma attenuation coefficient values increased from 0.562 cm-1 for 0 wt% Li-HAp to 2.190 cm-1 for 40 wt% Li-HAp. The alternating current conductivity increased with increasing frequency. The concentration of Li affect the values of dielectric constant where Li doped HAp of low dielectric constant can have an advantage for healing in bone fractures. The calcium to phosphorus ratio decreased from 1.43 to 1.37 with the addition of lithium indicating the Ca deficiency in the studied composites. Our findings lead to the conclusion that Li-HAp is a new nano-composite useful for medical applications and could be doped with gamma shield materials.

  3. Carbon nanoparticle doped micro-patternable nano-composites for wearable sensing applications (Conference Presentation)

    Science.gov (United States)

    Khosla, Ajit

    2017-04-01

    This talk focuses on preparation, characterization and micropatterning of electrically conducting KETJENBLACK carbon black nanoparticle (80 nm-diameter) doped Polydimethylsiloxane (PDMS) by employing extrusion mixing. Previously, we had reported fabrication of various micropatternable nanocomposites for wearable sensing applications vis solvent assisted ultrasonic mixing technique[1-16] . Extrusion mixing has an advantage as no organic solvents are used and homogenous dispersion of carbon nanoparticles is observed, which is confirmed by SEM analysis. The developed nanocomposite can be micropatterened using standard microfabrication techniques. It is also observed that percolation threshold occurs at 0.51 wt% of carbon nanoparticles in polymer matrix. Examples of developed nano-composites for wearable sensing applications for precision medicine will also be discussed. References: 1.http://summit.sfu.ca/item/12017 A. Khosla. Micropatternable multifunctional nanocomposite polymers for flexible soft MEMS applications. Diss. Applied Science: School of Engineering Science, 2011. 2. A. Khosla ; B. L. Gray; Fabrication of multiwalled carbon nanotube polydimethylsiloxne nanocomposite polymer flexible microelectrodes for microfluidics and MEMS. Proc. SPIE 7642, Electroactive Polymer Actuators and Devices (EAPAD) 2010, 76421V (April 09, 2010); doi:10.1117/12.847292. 3. Ang Li ; Ajit Khosla ; Connie Drewbrook ; Bonnie L. Gray; Fabrication and testing of thermally responsive hydrogel-based actuators using polymer heater elements for flexible microvalves. Proc. SPIE 7929, Microfluidics, BioMEMS, and Medical Microsystems IX, 79290G (February 14, 2011); doi:10.1117/12.873197. 4. Khosla, A. and Gray, B. L. (2010), Preparation, Micro-Patterning and Electrical Characterization of Functionalized Carbon-Nanotube Polydimethylsiloxane Nanocomposite Polymer. Macromol. Symp., 297: 210-218. doi:10.1002/masy.200900165 5. A. Khosla ; D. Hilbich ; C. Drewbrook ; D. Chung ; B. L. Gray; Large

  4. Mathematical Simulation of Temperature Profiles within Microwave Heated Wood Made for Wood-Based Nano composites

    International Nuclear Information System (INIS)

    Li, X.; He, X.; Lv, J.; Wu, Y.; Luo, Y.; Chen, H.

    2013-01-01

    High intensive microwave pretreatment is a new method to modify wood for the fabrication of wood-based nano composites. Based on the physical law on heat transfer, a mathematical model to describe the temperature profiles within wood heated by high intensive microwave was established and simulated in this research. The results showed that the temperature profiles within wood were related to microwave heating methods; The temperature inside wood firstly increased and then gradually decreased along the direction of microwave transmission when the unilateral microwave heating was applied, and the temperature difference along the thickness direction of wood was very significant; The temperature with wood firstly increased and then gradually decreased from the wood surface to interior when the bilateral microwave heating was applied. Compared with the unilateral microwave heating, bilateral microwave heating is a better microwave heating method for the more uniform wood microwave pretreatment.

  5. Effect of processing conditions on the mechanical properties of polypropylene/bentonite nano composites

    International Nuclear Information System (INIS)

    Alves, Tatianny S.; Cipriano, Pamela B.; Lira, Vanize F.; Canedo, Eduardo L.; Carvalho, Laura H. de

    2009-01-01

    This work dealt with the effect of processing conditions on the properties of polypropylene/bentonite compounds, using natural clay and an organoclay prepared with hexadecyl trimethyl ammonium bromide. Compounds with 1% clay were prepared by melt compounding in a single-screw extruder and in a counter-rotating twin-screw extruder, and characterized x-ray diffraction; tensile and impact mechanical tests. X ray diffraction results on clays and compounds show that the surfactant was incorporated within the clay galleries and that intercalated nano composites were obtained with the organoclay processed in either the single or the twin-screw extruder. The data also indicated that, without the addition of a compatibilizer, no significant variation of mechanical properties was observed for the composites processed in either extruder. (author)

  6. Glass transition temperature of polymer nano-composites with polymer and filler interactions

    Science.gov (United States)

    Hagita, Katsumi; Takano, Hiroshi; Doi, Masao; Morita, Hiroshi

    2012-02-01

    We systematically studied versatile coarse-grained model (bead spring model) to describe filled polymer nano-composites for coarse-grained (Kremer-Grest model) molecular dynamics simulations. This model consists of long polymers, crosslink, and fillers. We used the hollow structure as the filler to describe rigid spherical fillers with small computing costs. Our filler model consists of surface particles of icosahedra fullerene structure C320 and a repulsive force from the center of the filler is applied to the surface particles in order to make a sphere and rigid. The filler's diameter is 12 times of beads of the polymers. As the first test of our model, we study temperature dependence of volumes of periodic boundary conditions under constant pressures through NPT constant Andersen algorithm. It is found that Glass transition temperature (Tg) decrease with increasing filler's volume fraction for the case of repulsive interaction between polymer and fillers and Tg weakly increase for attractive interaction.

  7. Antimicrobial Activity of Hippurate Nano composite and Its Cytotoxicity Effect in Combination with Cytarabine against HL-60

    International Nuclear Information System (INIS)

    Al Ali, S.H.H.; Al-Qubaisi, M.; Ismail, M.; El Zowalaty, M.; Hussein, M.Z.; Ismail, M.

    2013-01-01

    Hippuric acid (HA) was intercalated into a zinc-layered hydroxide (ZLH) by direct reaction of an aqueous suspension of zinc oxide with an aqueous solution of hippuric acid to obtain hippurate nano composite (HAN). Various concentrations of hippuric acid (0.05, 0.2, and 0.4 molar) were used for the synthesis of the nano composite. The as-synthesized HAN using 0.2 molar was found to give a well-ordered layered nano composite material with an increase in the basal spacing to 21.3 Å which indicated the insertion of hippurate organic moiety into the ZLH interlayers. The cytotoxicity of HAN in combination with cytarabine against human promyelocytic leukemia cells (HL-60) was tested using MTT cell viability assay and trypan blue dye exclusion assay. The combination of cytarabine with HAN showed higher tumor suppression efficiency as compared to that of cytarabine alone. The IC 50 values of HAN/cytarabine combination and cytarabine alone were μg/mL and μg/mL, respectively. DNA fragmentation was also studied, and the exposure of HL-60 cells to cytarabine produced % DNA fragmentation compared to % when cells were exposed to combination of cytarabine with HAN. The antimicrobial activity of hippuric acid and HAN nano composite was carried out against Gram-positive bacteria, Gram-negative bacteria, and yeasts. It was found that Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus were more sensitive to HAN compared to Bacillus subtilis and Salmonella choleraesuis

  8. Effect of lateral size of graphene nano-sheets on the mechanical properties and machinability of alumina nano-composites

    Czech Academy of Sciences Publication Activity Database

    Porwal, H.; Saggar, Richa; Tatarko, P.; Grasso, S.; Saunders, T.; Dlouhý, Ivo; Reece, M. J.

    2016-01-01

    Roč. 42, č. 6 (2016), s. 7533-7542 ISSN 0272-8842 EU Projects: European Commission(XE) 264526 Institutional support: RVO:68081723 Keywords : Alumina * Graphene nano-sheets * Nano-composites * Mechanical properties * Machinability Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.986, year: 2016

  9. Improvement of mechanical and thermal properties of high energy electron beam irradiated HDPE/hydroxyapatite nano-composite

    Science.gov (United States)

    Mohammadi, M.; Ziaie, F.; Majdabadi, A.; Akhavan, A.; Shafaei, M.

    2017-01-01

    In this research work, the nano-composites of high density polyethylene/hydroxyapatite samples were manufactured via two methods: In the first method, the granules of high density polyethylene and nano-structure hydroxyapatite were processed in an internal mixer to prepare the nano-composite samples with a different weight percentage of the reinforcement phase. As for the second one, high density polyethylene was prepared in nano-powder form in boiling xylene. During this procedure, the hydroxyapatite nano-powder was added with different weight percentages to the solvent to obtain the nano-composite. In both of the procedures, the used hydroxyapatite nano-powder was synthesized via hydrolysis methods. The samples were irradiated under 10 MeV electron beam in 70-200 kGy of doses. Mechanical, thermal and morphological properties of the samples were investigated and compared. The results demonstrate that the nano-composites which we have prepared using nano-polyethylene, show better mechanical and thermal properties than the composites prepared from normal polyethylene granules, due to the better dispersion of nano-particles in the polymer matrix.

  10. Radiation effect on characterization and physical properties of polymer nano composites

    International Nuclear Information System (INIS)

    Tawfik, E.K.M.

    2013-01-01

    Polymeric materials are of interest in scientific and technological research, because they can be tailored to meet specific requirement for a verity of applications, this is mainly due to their light weight, good mechanical strength, and optical properties.From which, Poly Vinyl Alcohol (PVA) is one of the most important polymeric materials, because it has many applications in industry and is of relatively low cost in manufacture. It is well documented that electrical and optical properties of polymers can be improved to a desired limit through suitable doping. In this concern, and since Ag + is a fast conducting ion in a number of crystalline and amorphous materials, its incorporation within a polymeric system may be expected to enhance its electrical and optical properties. In the present study the PVA/Ag nano composite with different contents of inorganic phase of (2, 3, 4, 5, 6, 7, and 8) wt % were prepared by reduction of Ag + ions in PVA solution using gamma irradiation with different dose of (15, 25, 50, 75, 100) kGy. The Ag particle size was found to be around 14.0 nm based on the UV-Vis spectroscopy and Dynamic Light Scattering (DLS) measurements. Also, the structural studies of the synthesized PVA/Ag nano composites have been carried out through FTIR, and XRD studies. Further, the dependence of the optical and electrical properties of PVA on the concentration of the embedded nano-Ag was reported. As well, the effects of γ- irradiation have been studied applying UV-Vis spectroscopy and electrical characteristics measurements, respectively.

  11. The diametral tensile strength and hydrostability of polymer-ceramic nano-composite (pcnc) material prototypes

    Science.gov (United States)

    Yepez, Johanna

    Statement of the problem: There is a weak connection between the filler and the resin matrix of dental composites caused primarily by hydrolysis of silane coupling agent, therefore, jeopardizing the mechanical properties of the dental restorations. Purpose: The purpose of this study was to compare the diametral tensile strength (DTS) of a nano-mechanically bonded polymer ceramic nano composite (pcnc) versus the chemically bonding prototype polymer ceramic nano composite (pcnc) fabricated by using hydrolytically stable interphase. Materials and Methods: Composites were made with 60wt % filler, 38% triethyleneglycol dimethacrylate (TEDGMA), 1% camphorquinone (CQ) and 1% 2-(dimethylamino) ethyl methacrylate (DMAEMA). Tests for DTS were performed using a universal testing machine. The disk-shaped specimens were loaded in compression between two supporting plates at a crosshead speed of 0.5 mm/min until fracture. The samples, measuring 3 mm in height and 6 mm in diameter, were produced in a round stainless steel (SS) mold. A total of 144 samples were created. Groups of 48 samples were made for each of three different fillers. Specimens were soaked in artificial saliva at 37° for four time periods, dry(t=0), 1 day, 7 days, 28 days). At the end of each soaking time DTS tests were performed. Results: There where statistically significant differences in the DTS between the filler groups and the soaking times (p=dental composites is a detrimental factor in the mechanical behavior. The silanation of the filler particles have a positive influence on the mechanical properties of dental composites but the hydrolysis of the silane coupling agent can dramatically reduce the average lifetime of dental composites.

  12. Room temperature synthesis of high temperature stable lanthanum phosphate–yttria nano composite

    International Nuclear Information System (INIS)

    Sankar, Sasidharan; Raj, Athira N.; Jyothi, C.K.; Warrier, K.G.K.; Padmanabhan, P.V.A.

    2012-01-01

    Graphical abstract: A facile aqueous sol–gel route involving precipitation–peptization mechanism followed by electrostatic stabilization is used for synthesizing nanocrystalline composite containing lanthanum phosphate and yttria. Highlights: ► A novel lanthanum phosphate–Y 2 O 3 nano composite is synthesized for the first time using a modified facile sol gel process. ► The composite becomes crystalline at 600 °C and X-ray diffraction pattern is indexed for monoclinic LaPO 4 and cubic yttria. ► The composite synthesized was tested up to 1300 °C and no reaction between the phases of the constituents is observed with the morphologies of the phases being retained. -- Abstract: A facile aqueous sol–gel route involving precipitation–peptization mechanism followed by electrostatic stabilization is used for synthesizing nanocrystalline composite containing lanthanum phosphate and yttria. Lanthanum phosphate (80 wt%)–yttria (20 wt%) nano composite (LaPO 4 –20%Y 2 O 3 ), has an average particle size of ∼70 nm after heat treatment of precursor at 600 °C. TG–DTA analysis reveals that stable phase of the composite is formed on heating the precursor at 600 °C. The TEM images of the composite show rod shape morphology of LaPO 4 in which yttria is acquiring near spherical shape. Phase identification of the composite as well as the phase stability up to 1300 °C was carried out using X-ray diffraction technique. With the phases being stable at higher temperatures, the composite synthesized should be a potential material for high temperature applications like thermal barrier coatings and metal melting applications.

  13. Nitrate removal by Fe0/Pd/Cu nano-composite in groundwater.

    Science.gov (United States)

    Liu, Hongyuan; Guo, Min; Zhang, Yan

    2014-01-01

    Nitrate pollution in groundwater shows a great threat to the safety of drinking water. Chemical reduction by zero-valent iron is being considered as a promising technique for nitrate removal from contaminated groundwater. In this paper, Fe0/Pd/Cu nano-composites were prepared by the liquid-phase reduction method, and batch experiments of nitrate reduction by the prepared Fe0/Pd/Cu nano-composites under various operating conditions were carried out. It has been found that nano-Fe0/Pd/Cu composites processed dual functions: catalytic reduction and chemical reduction. The introduction of Pd and Cu not only improved nitrate removal rate, but also reduced the generation of ammonia. Nitrate removal rate was affected by the amount of Fe0/Pd/Cu, initial nitrate concentration, solution pH, dissolved oxygen (DO), reaction temperature, the presence of anions, and organic pollutant. Moreover, nitrate reduction by Fe0/Pd/Cu composites followed the pseudo-first-order reaction kinetics. The removal rate of nitrate and total nitrogen were about 85% and 40.8%, respectively, under the reaction condition of Fe-6.0%Pd-3.0%Cu amount of 0.25 g/L, pH value of 7.1, DO of 0.42 mg/L, and initial nitrate concentration of 100 mg/L. Compared with the previous studies with Fe0 alone or Fe-Cu, nano-Fe-6%Pd-3%Cu composites showed a better selectivity to N2.

  14. Cooperative cytotoxic activity of Zn and Cu in bovine serum albumin-conjugated ZnS/CuS nano-composites in PC12 cancer cells

    International Nuclear Information System (INIS)

    Wang, Hua-Jie; Yu, Xue-Hong; Wang, Cai-Feng; Cao, Ying

    2013-01-01

    Series of self-assembled and mono-dispersed bovine serum albumin (BSA)-conjugated ZnS/CuS nano-composites with different Zn/Cu ratios had been successfully synthesized by a combination method of the biomimetic synthesis and ion-exchange strategy under the gentle conditions. High-resolution transmission electron microscopy observation, Fourier transform infrared spectra and zeta potential analysis demonstrated that BSA-conjugated ZnS/CuS nano-composites with well dispersity had the hierarchical structure and BSA was a key factor to control the morphology and surface electro-negativity of final products. The real-time monitoring by atomic absorption spectroscopy and powder X-ray diffraction revealed that the Zn/Cu ratio of nano-composites could be controlled by adjusting the ion-exchange time. In addition, the metabolic and morphological assays indicated that the metabolic proliferation and spread of rat pheochromocytoma (PC12) cells could be inhibited by nano-composites, with the high anti-cancer activity at a low concentration (4 ppm). What were more important, Zn and Cu in nano-composites exhibited a positive cooperativity at inhibiting cancer cell functions. The microscope observation and biochemical marker analysis clearly revealed that the nano-composites-included lipid peroxidation and disintegration of membrane led to the death of PC12 cells. Summarily, the present study substantiated the potential of BSA-conjugated ZnS/CuS nano-composites as anti-cancer drug

  15. Thermal and mechanical properties of palm oil-based polyurethane acrylate/ clay nano composites prepared by in-situ intercalative method and electron beam radiation

    International Nuclear Information System (INIS)

    Salih, A.M.; Mansor Ahmad; Nor Azowa Ibrahim; Rida Tajau; Wan Mohd Zin Wan Yunus

    2013-01-01

    Full-text: Palm oil based-polyurethane acrylate (POBUA)/ clay nano composites were prepared via in-situ intercalative polymerization using epoxidized palm oil acrylate (EPOLA) and 4,4 ' methylene diphenyl diisocyante (MDI). Organically modified Montmorillonite (ODA-MMT) was incorporated in EPOLA (1, 3 and 5 % wt), and then subjected to polycondensation reaction with MDI. Nano composites solid films were obtained successfully by electron beam radiation induced free radical polymerization (curing). FTIR results reveal that the prepolymer was obtained successfully, with nano clay dispersed in the matrix. The intercalation of the clay in the polymer matrix was investigated by XRD and the interlayer spacing of clay was found to be increased up to 37 Angstrom, while the structure morphology of the nano composites was investigated by TEM and SEM. The nano composites were found to be a mixture of exfoliated and intercalated morphologies. The thermal stability of the nano composites was significantly increased by incorporation of nano clay into the polymer matrix. DSC results reveal that the T g was shifted to higher values, gradually with increasing the amount of filler in the nano composites. Tensile strength and Young's modulus of the nano composites showed remarkable improvement compared to the neat POBUA. (author)

  16. Cooperative cytotoxic activity of Zn and Cu in bovine serum albumin-conjugated ZnS/CuS nano-composites in PC12 cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hua-Jie, E-mail: wanghuajie972001@163.com; Yu, Xue-Hong; Wang, Cai-Feng; Cao, Ying, E-mail: caoying1130@sina.com [Henan Normal University, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, College of Chemistry and Chemical Engineering (China)

    2013-11-15

    Series of self-assembled and mono-dispersed bovine serum albumin (BSA)-conjugated ZnS/CuS nano-composites with different Zn/Cu ratios had been successfully synthesized by a combination method of the biomimetic synthesis and ion-exchange strategy under the gentle conditions. High-resolution transmission electron microscopy observation, Fourier transform infrared spectra and zeta potential analysis demonstrated that BSA-conjugated ZnS/CuS nano-composites with well dispersity had the hierarchical structure and BSA was a key factor to control the morphology and surface electro-negativity of final products. The real-time monitoring by atomic absorption spectroscopy and powder X-ray diffraction revealed that the Zn/Cu ratio of nano-composites could be controlled by adjusting the ion-exchange time. In addition, the metabolic and morphological assays indicated that the metabolic proliferation and spread of rat pheochromocytoma (PC12) cells could be inhibited by nano-composites, with the high anti-cancer activity at a low concentration (4 ppm). What were more important, Zn and Cu in nano-composites exhibited a positive cooperativity at inhibiting cancer cell functions. The microscope observation and biochemical marker analysis clearly revealed that the nano-composites-included lipid peroxidation and disintegration of membrane led to the death of PC12 cells. Summarily, the present study substantiated the potential of BSA-conjugated ZnS/CuS nano-composites as anti-cancer drug.

  17. Design and Fabrication of Al2O3-(W, TiC-TiN-Mo-Ni Nano-composite Cermet Tool Materials with Graded Structures

    Directory of Open Access Journals (Sweden)

    NI Xiu-ying

    2018-02-01

    Full Text Available Based on the analysis on temperature and stress distributions, as well as fatigue crack propagation in cutting tools, a model for designing compositional distribution and microstructure with graded characteristics was proposed. The addition of ductile phase and the introduction of the graded structure are beneficial to slow down the fatigue crack propagation rate and improve tool life.Al2O3-(W,TiC-TiN-Mo-Ni nano-composite tool material with graded structures was fabricated via two stage hot pressing sintering process, and the microstructure and mechanical properties were studied. The results show that the surface hardness, fracture toughness of inner layer and bending strength of the cermet with sintered gradient structure reach 19.258GPa, 10.015MPa·m1/2 and 1017.475MPa,respectively.The performance requirements to cutting tools were met. The dimple cleavage and torn edge of the binding phase in the fracture surfaces can be beneficial to the improvement of the fracture toughness and bending strength,so the resistance to fatigue crack propagation of tools is improved.

  18. Preparation of new series of poly(amide-imide) reinforced layer silicate nano composite containing N-trimellitimide-L-alanine

    International Nuclear Information System (INIS)

    Faghihi, K.; Soleimani, M.; Shabanian, M.

    2011-01-01

    A new poly(amide-imide)-montmorillonite series were generated through solution intercalation technique. Cloisite 20A was used as a modified montmorillonite for ample compatibility with the poly(amide-imide) (PAI) matrix. The PAI 5 chains were synthesized by the direct polycondensation reaction of N-trimellitylimido-L-alanine (3) with 4,4'-diamino diphenyl ether (4) in the presence of tryphenyl phosphites (TPP), CaCl 2 , pyridine and N-methyl-2-pyrrolidone (NMP). Morphology and structure of the resulting PAI-nano composite films 5a-5d with (5-20 Wt%) silicate particles were characterized by Ftir spectroscopy, X-ray diffraction and scanning electron microscopy. The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nano composites films were investigated by using UV-Vis spectroscopy, thermogravimetric analysis and water uptake measurements. (Author)

  19. Preparation of new series of poly(amide-imide) reinforced layer silicate nano composite containing N-trimellitimide-L-alanine

    Energy Technology Data Exchange (ETDEWEB)

    Faghihi, K.; Soleimani, M. [Polymer Research Laboratory, Department of Chemistry, Faculty of Science, Islamic Azad University, Arak Branch, Arak (Iran, Islamic Republic of); Shabanian, M., E-mail: k-faghihi@araku.ac.ir [Young Researches Club, Islamic Azad University, Arak Branch, Arak (Iran, Islamic Republic of)

    2011-07-01

    A new poly(amide-imide)-montmorillonite series were generated through solution intercalation technique. Cloisite 20A was used as a modified montmorillonite for ample compatibility with the poly(amide-imide) (PAI) matrix. The PAI 5 chains were synthesized by the direct polycondensation reaction of N-trimellitylimido-L-alanine (3) with 4,4'-diamino diphenyl ether (4) in the presence of tryphenyl phosphites (TPP), CaCl{sub 2}, pyridine and N-methyl-2-pyrrolidone (NMP). Morphology and structure of the resulting PAI-nano composite films 5a-5d with (5-20 Wt%) silicate particles were characterized by Ftir spectroscopy, X-ray diffraction and scanning electron microscopy. The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nano composites films were investigated by using UV-Vis spectroscopy, thermogravimetric analysis and water uptake measurements. (Author)

  20. Flow-induced crystallization of a nano composite of poly(butylene adipate-co-terephthalate)/montmorillonite

    International Nuclear Information System (INIS)

    Bonel, Alan B.; Rego, Bruna T.; Beatrice, Cesar A.G.; Marini, Juliano; Bretas, Rosario E.S.

    2011-01-01

    Poly(butylene adipate-co-terephthalate) (PBAT) with 5wt% of an organically modified montmorillonite with polar surfactant was prepared by melt blending in a co-rotational twin-screw extruder at 160 degree C. 100rpm and 1 kg/h. Both pure polymer and nano composite were characterized by wide measurements. The study of the flow-induced crystallization was also done by rheological measurements, monitoring the viscosity as a function of time. The nano clay's lamellas were intercalated in the polymer m loss moduli of the nano composite, at low frequencies, showed that the particles of the nano clay were well dispersed and distributed thru the PBAT matrix. Finally, the presence of the nano clay's particles reduced the induction tim crystals growth, due to the strong interactions with the PBAT chains. (author)

  1. Preparation and Characterization of Graphene-Based Magnetic Hybrid Nano composite

    International Nuclear Information System (INIS)

    Jashiela Wani Jusin; Madzlan Aziz

    2016-01-01

    Graphene-based magnetic hybrid nano composite has the advantage of exhibiting better performance as platform or supporting materials to develop novel properties of composite by increasing selectivity of the targeted adsorbate. The hybrid nano material was prepared by mixing and hydrolysing iron (II) and iron (III) salt precursors in the presence of GO dispersion through coprecipitation method followed by in situ chemical reduction of GO. The effect of weight loading ratio of Fe to GO (4:1, 2.5:1, 1:1 and 1:4) on structural properties of the hybrid nano materials was investigated. The presence of characteristic peaks in FTIR spectra indicated that GO has been successfully oxidized from graphite while the decrease in oxygenated functional groups and peaks intensity evidenced the formation of hybrid nano materials through the subsequent reduction process. The presence of characteristic peaks in XRD pattern denoted that magnetite nanoparticles disappeared at higher loading of GO. TEM micrograph showed that the best distribution of iron oxide particles on the surface of hybrid nano material occurred when the loading ratio of Fe to GO was fixed at 2:5 to 1. The reduced graphene oxide (RGO) sheets in the hybrid materials showed less wrinkled sheet like structure compared to GO due to exfoliation and reduction process during the synthesis. The layered morphology of GO degrades at higher concentrations of iron oxide. (author)

  2. Solution processed ternary blend nano-composite charge regulation layer to enhance inverted OLED performances

    Science.gov (United States)

    Kaçar, Rifat; Mucur, Selin Pıravadılı; Yıldız, Fikret; Dabak, Salih; Tekin, Emine

    2018-04-01

    Inverted bottom-emission organic light emitting diodes (IBOLEDs) have attracted increasing attention due to their exceptional air stability and applications in active-matrix displays. For gaining high IBOLED device efficiencies, it is crucial to develop an effective strategy to make the bottom electrode easy for charge injection and transport. Charge selectivity, blocking the carrier flow towards the unfavourable side, plays an important role in determining charge carrier balance and accordingly radiative recombination efficiency. It is therefore highly desirable to functionalize an interfacial layer which will perform many different tasks simultaneously. Here, we contribute to the hole-blocking ability of the zinc oxide/polyethyleneimine (ZnO:PEI) nano-composite (NC) interlayer with the intention of increasing the OLED device efficiency. With this purpose in mind, a small amount of 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBi) was added as a hole-blocking molecule into the binary blend of ZnO and PEI solution. The device with a ternary ZnO:PEI:TPBi NC interlayer achieved a maximum current efficiency of 38.20 cd A-1 and a power efficiency of 34.29 lm W-1 with a luminance of 123 200 cd m-2, which are high performance parameters for inverted device architecture. The direct comparisons of device performances incorporating ZnO only, ZnO/PEI bilayers, and ZnO:PEI binary NC counterparts were also performed, which shed light on the origin of device performance enhancement.

  3. Mechanical and microstructure of reinforced hydroxyapatite/calcium silicate nano-composites materials

    International Nuclear Information System (INIS)

    Beheri, Hanan H.; Mohamed, Khaled R.; El-Bassyouni, Gehan T.

    2013-01-01

    Highlights: ► Nano sized of HA and CS powders were prepared. ► Mechanical of HACS composites enhanced with content of CS. ► The apatite formation onto the composites is proved. -- Abstract: In this study, the nano sized hydroxyapatite (HA) and calcium silicate (CS) powders prepared by both chemical precipitation and sol–gel methods respectively. Biphasic nano-composites materials containing different ratios of HA and CS were fabricated and assessed using X-ray diffraction (XRD), Fourier transmission infrared reflectance (FT-IR), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques. The effect of variation of ratios between HA and CS on mechanical properties, microstructure and in vitro study was studied. The results proved that the mechanical properties were enhanced with increasing the CS ratio in the composite. In vitro study proved the formation and nucleation of apatite onto composites surfaces which contain low content of CS after one week of immersion. Finally, it is concluded that the HACS composites containing high HA content at the expense of CS content will be promising for bone substitute’s applications, especially in load bearing sites.

  4. Fabrication and mechanical evaluation of hydroxyapatite/oxide nano-composite materials.

    Science.gov (United States)

    Mohamed, Khaled R; Beherei, Hanan H; El Bassyouni, Gehan T; El Mahallawy, Nahed

    2013-10-01

    In the current study, the semiconducting metal oxides such as nano-ZnO and SiO2 powders were prepared via sol-gel technique and conducted on nano-hydroxyapatite (nHA) which was synthesized by chemical precipitation. The properties of fabricated nano-structured composites containing different ratios of HA, ZnO and SiO2 were examined using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM) and transmission electron microscope (TEM) techniques. The effect of the variation of ratios between the three components on mechanical, microstructure and in-vitro properties was assessed to explore the possibility of enhancing these properties. The results proved that the mechanical properties exhibited an increment with increasing the ZnO content at the extent of HA. In-vitro study proved the formation and nucleation of apatite onto the surface of the fabricated composites after one week of immersion. It is concluded that HA composites containing SiO2 or SiO2/ZnO content had a suitable mechanical properties and ability to form apatite particles onto the composite surface. Based on bioactivity behavior, Si-HA is more bioactive than pure hydroxyapatite and nano-arrangements will provide an interface for better bone formation. Therefore, these nano-composites will be promising as bone substitutes especially in load bearing sites. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Functional properties of extruded nano composites based on cassava starch, polyvinyl alcohol and montmorillonite

    International Nuclear Information System (INIS)

    Debiagi, Flavia; Matsuda, Daniel K.M.; Marengo, Vitor A.; Vercelheze, Ana Elisa S.; Mali, Suzana

    2011-01-01

    The objectives of this work were to produce biodegradable trays based on cassava starch (native or modified by acid), sugarcane fibers and nano clay (sodium montmorillonite) and also to characterize the produced trays according to their density, tensile strength, X-ray diffraction and biodegradability. The trays were obtained by thermoforming into a hydraulic press coupled to a Teflon mold (18 x 23 cm) at 130 degree C/ 20 min and 100 bars of pressure. The peak related to the nano clay (2 = 7.1 o ) were not observed in XRD patterns of the trays, suggesting the formation of an exfoliated structure in the nano composite. The addition of modified starch increased tensile strength and density of the samples, and the addition of fibers and nano clays decreased the tensile strength of native and modified starch trays. The weight loss of trays was not affected by the starch type, however the addition of fibers increased the biodegradation and the addition of nano clays decreased. (author)

  6. An Overview on the Improvement of Mechanical Properties of Ceramics Nano composites

    International Nuclear Information System (INIS)

    Silvestre, J.; Brito, J. D.; Silvestre, N.

    2015-01-01

    Due to their prominent properties (mechanical, stiffness, strength, thermal stability), ceramic composite materials (CMC) have been widely applied in automotive, industrial and aerospace engineering, as well as in biomedical and electronic devices. Because monolithic ceramics exhibit brittle behaviour and low electrical conductivity, CMC_s have been greatly improved in the last decade. CMC_s are produced from ceramic fibres embedded in a ceramic matrix, for which several ceramic materials (oxide or non-oxide) are used for the fibres and the matrix. Due to the large diversity of available fibres, the properties of CMC_s can be adapted to achieve structural targets. They are especially valuable for structural components with demanding mechanical and thermal requirements. However, with the advent of nanoparticles in this century, the research interests in CMC_s are now changing from classical reinforcement (e.g., microscale fibres) to new types of reinforcement at nano scale. This review paper presents the current state of knowledge on processing and mechanical properties of a new generation of CMC_s: Ceramics Nano composites (CNC_s)

  7. Graphene–Noble Metal Nano-Composites and Applications for Hydrogen Sensors

    Directory of Open Access Journals (Sweden)

    Sukumar Basu

    2017-10-01

    Full Text Available Graphene based nano-composites are relatively new materials with excellent mechanical, electrical, electronic and chemical properties for applications in the fields of electrical and electronic devices, mechanical appliances and chemical gadgets. For all these applications, the structural features associated with chemical bonding that involve other components at the interface need in-depth investigation. Metals, polymers, inorganic fibers and other components improve the properties of graphene when they form a kind of composite structure in the nano-dimensions. Intensive investigations have been carried out globally in this area of research and development. In this article, some salient features of graphene–noble metal interactions and composite formation which improve hydrogen gas sensing properties—like higher and fast response, quick recovery, cross sensitivity, repeatability and long term stability of the sensor devices—are presented. Mostly noble metals are effective for enhancing the sensing performance of the graphene–metal hybrid sensors, due to their superior catalytic activities. The experimental evidence for atomic bonding between metal nano-structures and graphene has been reported in the literature and it is theoretically verified by density functional theory (DFT. Multilayer graphene influences gas sensing performance via intercalation of metal and non-metal atoms through atomic bonding.

  8. Thermal Properties, Structure and Morphology of Graphene Reinforced Polyethylene Terephthalate/ Polypropylene Nano composites

    International Nuclear Information System (INIS)

    Inuwa, I.M.; Hassan, A.; Shamsudin, S.A.

    2014-01-01

    In this work the thermal properties, structure and morphology of a blend of polyethylene terephthalate (PET) and polypropylene (PP) reinforced with graphene nano platelets (GNP) were investigated. A blend of PET/ PP (70/ 30 weight percent) compatibilized with styrene-ethylene-butylene-styrene grafted maleic anhydride triblock copolymer (10 phr) were fabricated by melt extrusion process in a twin screw extruder. The effective thermal conductivity of the nano composites increased as a function of the GNP concentration. More than 80 % increase in effective thermal conductivity was observed for the 7 phr reinforced sample compared to the neat blend. This observation was attributed to the development interconnected GNP sheets which formed heat conductive bridges that are suitable for maximum heat transfer. However, in the case of thermal stability which is a function of dispersibility of GNP in polymer matrix, the maximum increase was observed at 3 phr GNP loading which could be attributed to the uniform dispersion of GNPs in the matrix. It is explained that the GNP nano fillers migrated to the surface of matrix forming an effective oxygen barrier due to char formation. Morphological studies revealed uniform dispersion graphene in the polymer matrix at 3 phr GNP loading along with isolated instances of exfoliation of the graphene layers. (author)

  9. Effect of Addition of Colloidal Silica to Films of Polyimide, Polyvinylpyridine, Polystyrene, and Polymethylmethacrylate Nano-Composites

    OpenAIRE

    Abdalla, Soliman; Al-Marzouki, Fahad; Obaid, Abdullah; Gamal, Salah

    2016-01-01

    Nano-composite films have been the subject of extensive work for developing the energy-storage efficiency of electrostatic capacitors. Factors such as polymer purity, nanoparticle size, and film morphology drastically affect the electrostatic efficiency of the dielectric material that forms the insulating film between the conductive electrodes of a capacitor. This in turn affects the energy storage performance of the capacitor. In the present work, we have studied the dielectric properties of...

  10. Effect of Alumina Addition to Zirconia Nano-composite on Low Temperature Degradation Process and Biaxial Strength

    Directory of Open Access Journals (Sweden)

    Moluk Aivazi

    2016-12-01

    Full Text Available Ceramic dental materials have been considered as alternatives to metals for dental implants application. In this respect, zirconia tetragonal stabilized with %3 yttrium, is of great importance among the ceramic materials for endosseous dental implant application. Because of its good mechanical properties and color similar to tooth. The aim and novelty of this study was to design and prepare Y-TZP nano-composite to reduce the degradation process at low temperature by alumina addition and maintaining submicron grain sized. Also, flexural strength of nano-composite samples was evaluated. Toward this purpose, alumina-Y-TZP nano-composites containing 0–30 vol% alumina (denoted as A-Y-TZP 0-30 were fabricated using α-alumina and Y-TZP nano-sized by sintering pressure less method. The synthesized samples were characterized using x-ray diffraction, field emission scanning electron microscopy equipped with energy dispersive x-ray spectroscopy techniques. Nano-composite samples with high density (≥96% and grain sized of ≤ 400 nm was obtained by sintering at 1270 °C for 170 min. After low temperature degradation test (LTD, A-Y-TZP20 and A-Y-TZP30 not showed monoclinic phase and the flexural strength in all of samples were higher than A-Y-TZP0. It was concluded that the grains were remained in submicron sized and A-Y-TZP20 and A-Y-TZP30 did not present biaxial strength reduction after LTD test.

  11. Interference of processing variables on the mechanical behavior of nano composites HDPE/clay; Interferencia das variaveis de processamento no comportamento mecanico de nanocompositos PEAD/argila

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, R. [Universidade Federal do Piaui, Teresina, PI (Brazil); Souza, D.D.; Nobrega, K.C.; Araujo, E.M.; Melo, T.J. [Universidade Federal de Campina Grande - UAEMa Campina Grande, PB (Brazil)

    2010-07-01

    Nano composites were processed using the technique of melt intercalation, starting from a concentrated polar compatibilizer / organo clay (PE-g-MA / organo clay) prepared in an internal mixer. The concentrate was incorporated into the matrix of PEAD by two methods: (I) twin screw contrarrotational extruder and (II) twin screw corrotational extruder, using two thread profiles (ROS and 2KB90), after extrusion, the specimens of the extruded composites were injection molded. The diffraction of X-ray was used to analyze the degree of expansion of the clays prepared, and the degree of exfoliation of nano composites developed. The interference of processing variables on mechanical properties was studied by the behavior of the modulus and tensile strength of nano composite systems. Observed similar behavior in the use of thread (or 2KB90 ROS) of the nano composites, with a reduction in modulus and tensile strength. (author)

  12. Polypropylene Nano composites Obtained by In Situ Polymerization Using Metallocenes Catalyst: Influence of the Nanoparticles on the Final Polymer Morphology

    International Nuclear Information System (INIS)

    Zapata, P.; Quijada, R.

    2012-01-01

    Polypropylene nano composites containing silica nanospheres based on the sol-gel methods were produced via in situ polymerization using a rac-Et(Ind) 2 ZrCl 2 /methylaluminoxane (MAO) system. Two different routes were used depending on the interaction between the silica nanoparticles with the catalytic system. In route 1 the nanoparticles were added together with the catalytic system (rac-Et(Ind) 2 ZrCl 2 )/(MAO) directly into the reactor, and in route 2 the metallocenes rac-Et(Ind) 2 ZrCl 2 was supported on silica nanospheres pretreated with (MAO). SEM images show that when the nanospheres were added by both routes, they were replicated in the final polymer particle morphology; this phenomenon was more pronounced for PP obtained by route 2. The polypropylene (PP) nano composites obtained by both routes had a slightly higher percent crystallinity and crystallinity temperatures than pure PP. Transmission electron microscopy (TEM) images show that the nanospheres were well dispersed into the polypropylene matrix, particularly in the nano composites obtained by the support system (route 2).

  13. Nano-composite of PtRu alloy electrocatalyst and electronically conducting polymer for use as the anode in a direct methanol fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Jongho Choi; Kyungwon Park; Hyekyung Lee; Youngmin Kim; Jaesuk Lee; Yungeun Sung [Kwangju Inst. of Science and Technology, Dept. of Materials Science and Engineering, Gwangju (Korea)

    2003-08-15

    Nano-composites comprised of PtRu alloy nanoparticles and an electronically conducting polymer for the anode electrode in direct methanol fuel cell (DMFC) were prepared. Two conducting polymers of poly(N-vinyl carbazole) and poly(9-(4-vinyl-phenyl)carbazole) were used for the nano-composite electrodes. Structural analyses were carried out using Fourier transform nuclear magnetic resonance spectroscopy, AC impedance spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Electrocatalytic activities were investigated by voltammetry and chronoamperometry in a 2 M CH{sub 3}OH/{sub 0.5} M H{sub 2}SO{sub 4} solution and the data compared with a carbon-supported PtRu electrode. XRD patterns indicated good alloy formation and nano-composite formation was confirmed by TEM. Electrochemical measurements and DMFC unit-cell tests indicate that the nano-composites could be useful in a DMFC, but its performance would be slightly lower than that of a carbon-supported electrode. The interfacial property between the PtRu-polymer nano-composite anode and the polymer electrolyte was good, as evidenced by scanning electron microscopy. For better performance in a DMFC, a higher electric conductivity of the polymer and a lower catalyst loss are needed in nano-composite electrodes. (Author)

  14. Work Hard / Play Hard

    OpenAIRE

    Burrows, J.; Johnson, V.; Henckel, D.

    2016-01-01

    Work Hard / Play Hard was a participatory performance/workshop or CPD experience hosted by interdisciplinary arts atelier WeAreCodeX, in association with AntiUniversity.org. As a socially/economically engaged arts practice, Work Hard / Play Hard challenged employees/players to get playful, or go to work. 'The game changes you, you never change the game'. Employee PLAYER A 'The faster the better.' Employer PLAYER B

  15. Fabrication and mechanical evaluation of hydroxyapatite/oxide nano-composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, Khaled R., E-mail: Kh_rezk1966@yahoo.com [Biomaterials Dept., National Research Centre, El-Behoos St., Cairo (Egypt); Beherei, Hanan H. [Biomaterials Dept., National Research Centre, El-Behoos St., Cairo (Egypt); Physics Dept., Faculty of Science, El-Taif University (Saudi Arabia); El Bassyouni, Gehan T. [Biomaterials Dept., National Research Centre, El-Behoos St., Cairo (Egypt); Medical Physics Dept., Faculty of Medicine, El-Taif University (Saudi Arabia); El Mahallawy, Nahed [Design and Production Engineering Department, Faculty of Engineering, Ain Shams University on secondment to the German University in Cairo (Egypt)

    2013-10-15

    In the current study, the semiconducting metal oxides such as nano-ZnO and SiO{sub 2} powders were prepared via sol–gel technique and conducted on nano-hydroxyapatite (nHA) which was synthesized by chemical precipitation. The properties of fabricated nano-structured composites containing different ratios of HA, ZnO and SiO{sub 2} were examined using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM) and transmission electron microscope (TEM) techniques. The effect of the variation of ratios between the three components on mechanical, microstructure and in-vitro properties was assessed to explore the possibility of enhancing these properties. The results proved that the mechanical properties exhibited an increment with increasing the ZnO content at the extent of HA. In-vitro study proved the formation and nucleation of apatite onto the surface of the fabricated composites after one week of immersion. It is concluded that HA composites containing SiO{sub 2} or SiO{sub 2}/ZnO content had a suitable mechanical properties and ability to form apatite particles onto the composite surface. Based on bioactivity behavior, Si-HA is more bioactive than pure hydroxyapatite and nano-arrangements will provide an interface for better bone formation. Therefore, these nano-composites will be promising as bone substitutes especially in load bearing sites. - Graphical abstract: Nano-structures of (a) HA, (b) ZnO and (c) SiO{sub 2} powders. Highlights: • The nano-structured composites containing different ratios of HA, ZnO and SiO{sub 2} were prepared. • ZnO helps improve the mechanical properties of HA composites. • SiO{sub 2} helps improve the bioactivity of HA composites.

  16. Investigation on Nano composite Membrane of Multi walled Carbon Nano tube Reinforced Polycarbonate Blend for Gas Separation

    International Nuclear Information System (INIS)

    Kausar, A.

    2016-01-01

    Carbon nano tube has been explored as a nano filler in high performance polymeric membrane for gas separation. In this regard, nano composite membrane of polycarbonate (PC), poly(vinylidene fluoride-co-hexafluoropropylene) (PVFHFP), and multi walled carbon nano tube (MWCNT) was fabricated via phase inversion technique. Poly (ethylene glycol) (PEG) was employed for the compatibilization of the blend system. Two series of PC/PVFHFP/PEG were developed using purified P-MWCNT and acid functional A-MWCNT nano filler. Scanning and transmission electron micrographs have shown fine nano tube dispersion and wetting by matrix, compared with the purified system. Tensile strength and Young s modulus of PC/PVFHFP/PEG/MWCNT-A 1-5 were found to be in the range of 63.6-72.5 MPa and 110.6-122.1 MPa, respectively. The nano composite revealed 51% increase in Young s modulus and 28% increase in tensile stress relative to the pristine blend. The A-MWCNT was also effective in enhancing the perm selectivity αCO 2 /N 2 (31.2-39.9) of nano composite membrane relative to the blend membrane (21.6). The permeability ρCO 2 of blend was 125.6 barrer; however, the functional series had enhancedρCO 2 values ranging from 142.8 to 186.6 barrer. Moreover, A-MWCNT loading improved the gas diffusivity of PC/PVFHFP/PEG/MWCNT-A 1-5; however, filler content did not significantly influence the CO 2 and N 2 solubility.

  17. Gold surface supported spherical liposome-gold nano-particle nano-composite for label free DNA sensing.

    Science.gov (United States)

    Bhuvana, M; Narayanan, J Shankara; Dharuman, V; Teng, W; Hahn, J H; Jayakumar, K

    2013-03-15

    Immobilization of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) liposome-gold nano-particle (DOPE-AuNP) nano-composite covalently on 3-mercaptopropionic acid (MPA) on gold surface is demonstrated for the first time for electrochemical label free DNA sensing. Spherical nature of the DOPE on the MPA monolayer is confirmed by the appearance of sigmoidal voltammetric profile, characteristic behavior of linear diffusion, for the MPA-DOPE in presence of [Fe(CN)(6)](3-/4-) and [Ru(NH(3))(6)](3+) redox probes. The DOPE liposome vesicle fusion is prevented by electroless deposition of AuNP on the hydrophilic amine head groups of the DOPE. Immobilization of single stranded DNA (ssDNA) is made via simple gold-thiol linkage for DNA hybridization sensing in the presence of [Fe(CN)(6)](3-/4-). The sensor discriminates the hybridized (complementary target hybridized), un-hybridized (non-complementary target hybridized) and single base mismatch target hybridized surfaces sensitively and selectively without signal amplification. The lowest target DNA concentration detected is 0.1×10(-12)M. Cyclic voltammetry (CV), electrochemical impedance (EIS), differential pulse voltammetry (DPV) and quartz crystal microbalance (QCM) techniques are used for DNA sensing on DOPE-AuNP nano-composite. Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), Atomic Force Microscopy (AFM), Dynamic Light Scattering (DLS) and Ultraviolet-Visible (UV) spectroscopic techniques are used to understand the interactions between the DOPE, AuNP and ssDNA. The results indicate the presence of an intact and well defined spherical DOPE-AuNP nano-composite on the gold surface. The method could be applied for fabrication of the surface based liposome-AuNP-DNA composite for cell transfection studies at reduced reagents and costs. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Omega-3 PUFA concentration by a novel PVDF nano-composite membrane filled with nano-porous silica particles.

    Science.gov (United States)

    Ghasemian, Samaneh; Sahari, Mohammad Ali; Barzegar, Mohsen; Ahmadi Gavlighi, Hasan

    2017-09-01

    In this study, polyvinylidene fluoride (PVDF) and nano-porous silica particle were used to fabricate an asymmetric nano-composite membrane. Silica particles enhanced the thermal stability of PVDF/SiO 2 membranes; increasing the decomposition temperature from 371°C to 408°C. Cross sectional morphology showed that silica particles were dispersed in polymer matrix uniformly. However, particle agglomeration was found at higher loading of silica (i.e., 20 by weight%). The separation performance of nano-composite membranes was also evaluated using the omega-3 polyunsaturated fatty acids (PUFA) concentration at a temperature and pressure of 30°C and 4bar, respectively. Silica particle increased the omega-3PUFA concentration from 34.8 by weight% in neat PVDF to 53.9 by weight% in PVDF with 15 by weight% of silica. Moreover, PVDF/SiO 2 nano-composite membranes exhibited enhanced anti-fouling property compared to neat PVDF membrane. Fouling mechanism analysis revealed that complete pore blocking was the predominant mechanism occurring in oil filtration. The concentration of omega-3 polyunsaturated fatty acids (PUFA) is important in the oil industries. While the current methods demand high energy consumptions in concentrating the omega-3, membrane separation technology offers noticeable advantages in producing pure omega-3 PUFA. Moreover, concentrating omega-3 via membrane separation produces products in the triacylglycerol form which possess better oxidative stability. In this work, the detailed mechanisms of fouling which limits the performance of membrane separation were investigated. Incorporating silica particles to polymeric membrane resulted in the formation of mixed matrix membrane with improved anti-fouling behaviour compared to the neat polymeric membrane. Hence, the industrial potential of membrane processing to concentrate omega-3 fatty acids is enhanced. Copyright © 2017. Published by Elsevier Ltd.

  19. Correlation between nanostructural and electrical properties of barium titanate-based glass-ceramic nano-composites

    Energy Technology Data Exchange (ETDEWEB)

    Al-Assiri, M.S., E-mail: msassiri@kku.edu.sa [Department of Physics, King Khaled University, P.O. Box 9003, Abha (Saudi Arabia); El-Desoky, M.M., E-mail: mmdesoky@gmail.com [Department of Physics, King Khaled University, P.O. Box 9003, Abha (Saudi Arabia); Department of Physics, Faculty of Science, Suez Canal University, Suez (Egypt)

    2011-09-08

    Highlights: > Glasses have been transformed into nanomaterials by annealing at crystallization temperature. > Glass-ceramic nano-composites are important because of their new physical. > Grain sizes are the most significant structural parameter in electronic nanocrystalline phases. > These phases are very high electrical conductivity. > Hence, glass-ceramic nanocrystals are expected to be used, as gas sensors. - Abstract: Glasses in the system BaTiO{sub 3}-V{sub 2}O{sub 5}-Bi{sub 2}O{sub 3} have been transformed into glass-ceramic nano-composites by annealing at crystallization temperature T{sub cr} determined from DSC thermograms. After annealing they consist of small crystallites embedded in glassy matrix. The crystallization temperature T{sub cr} increases with increasing BaTiO{sub 3} content. XRD and TEM of the glass-ceramic nano-composites show that nanocrystals were embedded in the glassy matrix with an average grain size of 25 nm. The resulting materials exhibit much higher electrical conductivity than the initial glasses. It was postulated that the major role in the conductivity enhancement of these nanomaterials is played by the developed interfacial regions between crystalline and amorphous phases, in which the concentration of V{sup 4+}-V{sup 5+} pairs responsible for electron hopping, has higher than values that inside the glassy matrix. The experimental results were discussed in terms of a model proposed in this work and based on a 'core-shell' concept. From the best fits, reasonable values of various small polaron hopping (SPH) parameters were obtained. The conduction was attributed to non-adiabatic hopping of small polaron.

  20. Preparation and characterization of functionalized cellulose nano crystals with methyl adipoyl chloride used to prepare chitosan grafting nano composite

    International Nuclear Information System (INIS)

    Mesquita, Joao Paulo de; Teixeira, Ivo F.; Donnici, Claudio L.; Pereira, Fabiano V.

    2011-01-01

    Cellulose nano crystals (CNCs) were prepared from eucalyptus pulp and functionalized with methyl adipoyl chloride. The nano materials were characterized by different techniques including FTIR, 1H NMR and XRD which showed that the functionalization occurs only on the surface of the nano structures without change in crystalline structure of the nanoparticles. The new-functionalized CNCs were used as reinforcement in the preparation of a nano composite with chitosan, through the formation of a covalent bond between the nano filler and matrix. Preliminary results of mechanical tests indicate an improvement in tensile strength and increase in deformation of chitosan. (author)

  1. Magnetic nanoparticles based nano-composites: synthesis, contribution of the fillers dispersion and the chains conformation on the reinforcement properties

    International Nuclear Information System (INIS)

    Robbes, Anne-Sophie

    2011-01-01

    The mechanical properties of polymeric nano-composite films can be considerably enhanced by the inclusion of inorganic nanoparticles due to two main effects: (i) the local structure of fillers dispersion and (ii) the potential modification of the chains conformation and dynamics in the vicinity of the filler/polymer interface. However, the precise mechanisms which permit to correlate these contributions at nano-metric scale to the macroscopic mechanical properties of the materials are actually poorly described. In such a context, we have synthesized model nano-composites based on magnetic nanoparticles of maghemite γ-Fe 2 O 3 (naked or grafted with a polystyrene (PS) corona by radical controlled polymerization) dispersed in a PS matrix, that we have characterized by combining small angle scattering (X-Ray and neutron) and transmission electronic microscopy. By playing on different parameters such as the particle size, the concentration, or the size ratio between the grafted chains and the ones of the matrix in the case of the grafted fillers, we have obtained nano-composite films a large panel of controlled and reproducible controlled filler structures, going from individual nanoparticles or fractal aggregates up to the formation of a connected network of fillers. By applying an external magnetic field during the film processing, we succeeded in aligning the different structures along the direction of the field and we obtained materials with remarkable anisotropic reinforcement properties. The conformation of the chains of the matrix, experimentally determined thanks to the specific properties of neutron contrast of the system, is not affected by the presence of the fillers, whatever their confinement, the dispersion the fillers or their chemical state surface. The alignment of the fillers along the magnetic field has allowed us to describe precisely the evolution of the reinforcement modulus of the materials with the structural reorganization of the fillers and

  2. P(AN-MMA)/TiO_2 Nano-composite Polymer Electrolyte by in-situ Polymerization

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Introduction With the development of portable electric devices,polymer lithium ion batteries (PLiBs) have been widely used as the power sources because of their high energy density and safe property[1].P(AN-MMA) copolymer is a kind of cheap macromolecules easily dissolving in the polar solvents such as carbonate,it has been applied as gel polymer electrolyte in PLiBs.Here we prepare a kind of highly conductive nano-composite polymer electrolytes using the P(AN-MMA) copolymer incorporated with TiO2 nan...

  3. Removal of Dibenzothiophene Using Activated Carbon/γ-Fe2O3 Nano-Composite: Kinetic and Thermodynamic Investigation of the Removal Process

    Directory of Open Access Journals (Sweden)

    Maryam Fayazi

    2015-12-01

    Full Text Available In the present study, removal of dibenzothiophene (DBT from model oil (n-hexane was investigated using magnetic activated carbon (MAC nano-composite adsorbent. The synthesized nano-composite was characterized by FT-IR, FE-SEM, BET and VSM techniques. The MAC nano-composite exhibited a nearly superparamagnetic property with a saturation magnetization (Ms of 29.2 emu g-1, which made it desirable for separation under an external magnetic field. The magnetic adsorbent afforded a maximum adsorption capacity of 38.0 mg DBT g-1 at the optimized conditions (adsorbent dose, 8 g l-1; contact time, 1 h; temperature, 25 °C. Langmuir, Freundlich and Temkin isotherm models were used to fit equilibrium data for MAC nano-composite. Adsorption process could be well described by the Langmuir model. Kinetic studies were carried out and showed the sorption kinetics of DBT was best described by a pseudo-second-order kinetic model. In addition, the MAC nano-composite exhibited good capability of recycling to adsorb DBT in gasoline deep desulfurization.

  4. Structural and magnetic characteristics of PVA/CoFe{sub 2}O{sub 4} nano-composites prepared via mechanical alloying method

    Energy Technology Data Exchange (ETDEWEB)

    Rashidi, S.; Ataie, A., E-mail: aataie@ut.ac.ir

    2016-08-15

    Highlights: • Single phase CoFe{sub 2}O{sub 4} nano-particles synthesized in one step by mechanical alloying. • PVA/CoFe{sub 2}O{sub 4} magnetic nano-composites were fabricated via mechanical milling. • FTIR confirmed the interaction between PVA and magnetic CoFe{sub 2}O{sub 4} particles. • Increasing in milling time and PVA amount led to well dispersion of CoFe{sub 2}O{sub 4}. - Abstract: In this research, polyvinyl alcohol/cobalt ferrite nano-composites were successfully synthesized employing a two-step procedure: the spherical single-phase cobalt ferrite of 20 ± 4 nm mean particle size was synthesized via mechanical alloying method and then embedded into polymer matrix by intensive milling. The results revealed that increase in polyvinyl alcohol content and milling time causes cobalt ferrite particles disperse more homogeneously in polymer matrix, while the mean particle size and shape of cobalt ferrite have not been significantly affected. Transmission electron microscope images indicated that polyvinyl alcohol chains have surrounded the cobalt ferrite nano-particles; also, the interaction between polymer and cobalt ferrite particles in nano-composite samples was confirmed. Magnetic properties evaluation showed that saturation magnetization, coercivity and anisotropy constant values decreased in nano-composite samples compared to pure cobalt ferrite. However, the coercivity values of related nano-composite samples enhanced by increasing PVA amount due to domain wall mechanism.

  5. Synthesis and characterization of water-soluble and conducting sulfonated polyaniline/para-phenylenediamine-functionalized multi-walled carbon nanotubes nano-composite

    International Nuclear Information System (INIS)

    Xu Jun; Yao Pei; Li Xuan; He Fei

    2008-01-01

    Water-soluble and conducting sulfonated polyaniline (SPAN)/phenylamine groups contained MWNTs (p-MWNTs) nano-composite were synthesized by in situ oxidation polymerization followed by sulfonation and hydrolysis. TEM, Raman spectroscopy, FTIR, XPS, TGA and standard four-probe methods were employed to characterize morphology, chemical structure and performance of the nano-composite. The results show that phenylamine groups are grafted on the surface of p-MWNTs via amide bond and oxidized phenylamine groups initiate polyaniline polymerized on the surface of p-MWNTs. SPAN chains covalently attached to p-MWNTs render p-MWNTs compatibility with SPAN matrix and lead to SPAN/p-MWNTs nano-composite highly soluble and stable in water. Improved thermal stability illuminate existence of a new phase in the nano-composite where there is chemical interaction between p-MWNTs and SPAN coatings. Owing to incorporation of p-MWNTs conductivity of the nano-composite at room temperature is increased by about two orders of magnitude over neat SPAN

  6. Novel Preparation of Nano-Composite CuO-Cr2O3 Using Ctab-Template Method and Efficient for Hydrogenation of Biomass-Derived Furfural

    Science.gov (United States)

    Yan, Kai; Wu, Xu; An, Xia; Xie, Xianmei

    2013-02-01

    A simple route to fabricate nano-composite oxides CuO-Cr2O3 using hexadecyltrimethylammonium bromide (CTAB)-templated Cu-Cr hydrotalcite as the precursor is presented. This novel method is based on CTAB-templating effect for mesostructure directing and using the cheap metal nitrate, followed by removal of CTAB. It was indicated that the nano-composite CuO-Cr2O3 was formed during the removal of CTAB. X-ray diffraction (XRD) and transitional electronic microscopy (TEM) revealed nice nano-composite oxides CuO-Cr2O3 were formed with high crystallinity. N2 adsorption and desorption indicated that a high surface area of 170.5 m2/g with a pore size of 2.7 nm of the nano-composite CuO-Cr2O3 was facilely resulted. The as-synthesized nano-composite oxides CuO-Cr2O3 display good catalytic activities for hydrogenation of furfural to furfuryl alcohol, whereas 86% selectivity was achieved at 75% conversion of furfural.

  7. One-Pot Hydrothermal Synthesis of Magnetite Prussian Blue Nano-Composites and Their Application to Fabricate Glucose Biosensor

    Directory of Open Access Journals (Sweden)

    Ezzaldeen Younes Jomma

    2016-02-01

    Full Text Available In this work, we presented a simple method to synthesize magnetite Prussian blue nano-composites (Fe3O4-PB through one-pot hydrothermal process. Subsequently, the obtained nano-composites were used to fabricate a facile and effective glucose biosensor. The obtained nanoparticles were characterized using transmission electron microscopy, scanning electron microscopy, Fourier-transform infrared spectroscopy, UV-vis absorbance spectroscopy, cyclic voltammetry and chronoamperometry. The resultant Fe3O4-PB nanocomposites have magnetic properties which could easily controlled by an external magnetic field and the electro-catalysis of hydrogen peroxide. Thus, a glucose biosensor based on Fe3O4-PB was successfully fabricated. The biosensor showed super-electrochemical properties toward glucose detection exhibiting fast response time within 3 to 4 s, low detection limit of 0.5 µM and wide linear range from 5 µM to 1.2 mM with sensitivity of 32 µA∙mM−1∙cm−2 and good long-term stability.

  8. Digital selective fabrication of micro/nano-composite structured TiO2 nanorod arrays by laser direct writing

    Science.gov (United States)

    Jiang, Wei; He, Xiaoning; Liu, Hongzhong; Yin, Lei; Shi, Yongsheng; Ding, Yucheng

    2014-11-01

    In this article, we report on the digital selective fabrication of micro/nano-composite structured TiO2 nanorod arrays by laser direct writing. The pattern of TiO2 nanorod arrays can be easily designed and fabricated by laser scanning technology integrated with a computer-aided design system, which allows a high degree of freedom corresponding to the various pattern design demands. The approach basically involves the hydrothermal growth of TiO2 nanorod arrays on a transparent conductive substrate, the micropattern of TiO2 nanorod arrays and surface fluorination treatment. With these micro/nano-composite TiO2 nanorod array based films, we have demonstrated superhydrophilic patterned TiO2 nanorod arrays with rapid water spreading ability and superhydrophobic patterned TiO2 nanorod arrays with an excellent droplet bouncing effect and a good self-cleaning performance. The dynamic behaviours of the water droplets observed on the patterned TiO2 nanorod arrays were demonstrated by experiments and simulated by a finite element method. The approaches we will show are expected to provide potential applications in fields such as self-cleaning, surface protection, anticrawling and microfluidic manipulation.

  9. Significantly Elevated Dielectric and Energy Storage Traits in Boron Nitride Filled Polymer Nano-composites with Topological Structure

    Science.gov (United States)

    Feng, Yefeng; Zhang, Jianxiong; Hu, Jianbing; Li, Shichun; Peng, Cheng

    2018-03-01

    Interface induced polarization has a prominent influence on dielectric properties of 0-3 type polymer based composites containing Si-based semi-conductors. The disadvantages of composites were higher dielectric loss, lower breakdown strength and energy storage density, although higher permittivity was achieved. In this work, dielectric, conductive, breakdown and energy storage properties of four nano-composites have been researched. Based on the cooperation of fluoropolymer/alpha-SiC layer and fluoropolymer/hexagonal-BN layer, it was confirmed constructing the heterogeneous layer-by-layer composite structure rather than homogeneous mono-layer structure could significantly reduce dielectric loss, promote breakdown strength and increase energy storage density. The former worked for a larger dielectric response and the latter layer acted as a robust barrier of charge carrier transfer. The best nano-composite could possess a permittivity of 43@100 Hz ( 3.3 times of polymer), loss of 0.07@100 Hz ( 37% of polymer), discharged energy density of 2.23 J/cm3@249 kV/cm ( 10 times of polymer) and discharged energy efficiency of 54%@249 kV/cm ( 5 times of polymer). This work might enlighten a facile route to achieve the promising high energy storage composite dielectrics by constructing the layer-by-layer topological structure.

  10. The Degradation of Mechanical Properties in Halloysite Nano clay-Polyester Nano composites Exposed in Seawater Environment

    International Nuclear Information System (INIS)

    Saharudin, M.S.; Saharudin, M. Sh.; Wei, J.; Shyha, I.; Inam, F.

    2016-01-01

    Polyester based polymers are extensively used in aggressive marine environments; however, inadequate data is available on the effects of the seawater on the polyester based nano composites mechanical properties. This paper reports the effect of seawater absorption on the mechanical properties degradation of halloysite nano clay-polyester nano composites. Results confirmed that the addition of halloysite nano clay into polyester matrix was found to increase seawater uptake and reduce mechanical properties compared to monolithic polyester. The maximum decreases in microhardness, tensile and flexural properties, and impact toughness were observed in case of 1 wt% nano clay. The microhardness decreased from 107 HV to 41.7 HV (61% decrease). Young s modulus decreased from 0.6 GPa to 0.4 GPa (33% decrease). The flexural modulus decreased from 0.6 GPa to 0.34 GPa (43% decrease). The impact toughness dropped from 0.71 kJ/m"2 to 0.48 kJ/m"2 (32% decrease). Interestingly, the fracture toughnessκ_1C increased with the addition of halloysite nano clay due to the plasticization effect of the resin matrix. SEM images revealed the significant reduction in mechanical properties in case of 1 wt% reinforcement which is attributed to the degradation of the nano clay-matrix interface influenced by seawater absorption and agglomeration of halloysite nano clay.

  11. Effect of stacking sequence and surface treatment on the thermal conductivity of multilayered hybrid nano-composites

    Science.gov (United States)

    Papanicolaou, G. C.; Pappa, E. J.; Portan, D. V.; Kotrotsos, A.; Kollia, E.

    2018-02-01

    The aim of the present investigation was to study the effect of both the stacking sequence and surface treatment on the thermal conductivity of multilayered hybrid nano-composites. Four types of multilayered hybrid nanocomposites were manufactured and tested: Nitinol- CNTs (carbon nanotubes)- Acrylic resin; Nitinol- Acrylic resin- CNTs; Surface treated Nitinol- CNTs- Acrylic resin and Surface treated Nitinol- Acrylic resin- CNTs. Surface treatment of Nitinol plies was realized by means of the electrochemical anodization. Surface topography of the anodized nitinol sheets was investigated through Scanning Electron Microscopy (SEM). It was found that the overall thermal response of the manufactured multilayered nano-composites was greatly influenced by both the anodization and the stacking sequence. A theoretical model for the prediction of the overall thermal conductivity has been developed considering the nature of the different layers, their stacking sequence as well as the interfacial thermal resistance. Thermal conductivity and Differential Scanning Calorimetry (DSC) measurements were conducted, to verify the predicted by the model overall thermal conductivities. In all cases, a good agreement between theoretical predictions and experimental results was found.

  12. Fe{sub 2}O{sub 3}-Poly-pyrrole hybrid nano-composite materials for super-capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Mallouki, M.; Tran-Van, F.; Sarrazin, C.; Chevrot, C. [Cergy-Pontoise Univ., Lab. de Physicochimie des Polymeres et des Interfaces (LPPI), EA 2528 95 (France); Fauvarque, J.F. [CNAM, Lab. d' Electrochimie Industrielle, 75 - Paris (France); Simon, P. [Universite Paul Sabatier, CIRIMAT-LCMIE, UMR 5085, 31 - Toulouse (France); De, A. [Saha Institute of Nuclear Physics, Calcutta (India)

    2004-07-01

    Fe{sub 2}O{sub 3}-Poly-pyrrole hybrid nano-composite materials chemically synthesized from colloid particles of iron oxide in aqueous solution have been processed to realize electrode materials for super-capacitor applications. The performances have been evaluated by cyclic voltammetry and galvano-static techniques in a three-electrode cell. The capacitance of Fe{sub 2}O{sub 3}-PPy hybrid nano-composite doped with para-toluene-sulfonate reaches 47 mAh/g in PC/NEt{sub 4}BF{sub 4} with a good stability during cycling (loss of 3% after 1000 cycles). Transmission Electronic Microscopy indicates a porous nano-structure with spherical particles in a range of 400-500 nm which ensures a good accessibility of the electrolyte in the bulk of the electro-active hybrid material. Preliminary studies with room temperature ionic liquid show promising results since the specific capacitance reaches 427 F/g in 1- ethyl-3-methyl-imidazolium bis((tri-fluoro-methyl)sulfonyl)amide (EMITFSI). (authors)

  13. Iron oxide functionalized graphene nano-composite for dispersive solid phase extraction of chemical warfare agents from aqueous samples.

    Science.gov (United States)

    Chinthakindi, Sridhar; Purohit, Ajay; Singh, Varoon; Tak, Vijay; Goud, D Raghavender; Dubey, D K; Pardasani, Deepak

    2015-05-15

    Present study deals with the preparation and evaluation of graphene based magnetic nano-composite for dispersive solid phase extraction of Chemical Weapons Convention (CWC) relevant chemicals from aqueous samples. Nano-composite, Fe3O4@SiO2-G was synthesized by covalently bonding silica coated Fe3O4 onto the graphene sheets. Nerve agents (NA), Sulfur mustard (SM) and their non-toxic environmental markers were the target analytes. Extraction parameters like amount of sorbent, extraction time and desorption conditions were optimized. Dispersion of 20 milligram of sorbent in 200mL of water sample for 20min. followed by methanol/chloroform extraction produced average to good recoveries (27-94%) of targeted analytes. Recoveries of real agents exhibited great dependency upon sample pH and ionic strength. Sarin produced maximum recovery under mild acidic conditions (56% at pH 5) while VX demanded alkaline media (83% at pH 9). Salts presence in the aqueous samples was found to be advantageous, raising the recoveries to as high as 94% for SM. Excellent limits of detection (LOD) for sulphur mustard and VX (0.11ngmL(-1) and 0.19ngmL(-1) respectively) proved the utility of the developed method for the off-site analysis of CWC relevant chemicals. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Functional properties of extruded nano composites based on cassava starch, polyvinyl alcohol and montmorillonite; Propriedades funcionais de nanocompositos extrusados de amido de mandioca, alcool polivinilico e montmorilonita

    Energy Technology Data Exchange (ETDEWEB)

    Debiagi, Flavia; Mali, Suzana [Departamento de Bioquimica e Biotecnologia, Universidade Estadual de Londrina, PR (Brazil)

    2011-07-01

    The objectives of this work were to produce expanded nano composites (foams) based on starch, PVA and sodium montmorillonite and characterize them according to their expansion index (EI), density, water absorption capacity (WSC), mechanical properties and X-ray diffraction. The nano composites were prepared in a single-screw extruder using different starch contents (97.6 - 55.2 g/100 g formulation), PVA (0 - 40 g/100 g formulation), unmodified nano clay - Closite - Na (0 - 4. 8 g/100 g formulation) and glycerol (20 g/100 g formulation) as plasticizer. The addition of montmorillonite and PVA resulted in an increase of EI and a decrease of density of the samples, and reduced WSC and increased the mechanical strength of the foams. Through the analysis of X-ray diffraction can be observed that the addition of montmorillonite led to production of intercalated nano composites in all samples. (author)

  15. Synthesis of Silica Nanoparticles by Sol-Gel: Size-Dependent Properties, Surface Modification, and Applications in Silica-Polymer Nano composites-A Review

    International Nuclear Information System (INIS)

    Ismail, A.R.; Vejayakumaran, P.

    2012-01-01

    Application of silica nanoparticles as fillers in the preparation of nano composite of polymers has drawn much attention, due to the increased demand for new materials with improved thermal, mechanical, physical, and chemical properties. Recent developments in the synthesis of monodispersed, narrow-size distribution of nanoparticles by sol-gel method provide significant boost to development of silica-polymer nano composites. This paper is written by emphasizing on the synthesis of silica nanoparticles, characterization on size-dependent properties, and surface modification for the preparation of homogeneous nano composites, generally by sol-gel technique. The effect of nano silica on the properties of various types of silica-polymer composites is also summarized.

  16. Hard electronics; Hard electronics

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    Hard material technologies were surveyed to establish the hard electronic technology which offers superior characteristics under hard operational or environmental conditions as compared with conventional Si devices. The following technologies were separately surveyed: (1) The device and integration technologies of wide gap hard semiconductors such as SiC, diamond and nitride, (2) The technology of hard semiconductor devices for vacuum micro- electronics technology, and (3) The technology of hard new material devices for oxides. The formation technology of oxide thin films made remarkable progress after discovery of oxide superconductor materials, resulting in development of an atomic layer growth method and mist deposition method. This leading research is expected to solve such issues difficult to be easily realized by current Si technology as high-power, high-frequency and low-loss devices in power electronics, high temperature-proof and radiation-proof devices in ultimate electronics, and high-speed and dense- integrated devices in information electronics. 432 refs., 136 figs., 15 tabs.

  17. Characterization of Ni-P-SiO2 nano-composite coating on magnesium

    Science.gov (United States)

    Sadreddini, S.; Salehi, Z.; Rassaie, H.

    2015-01-01

    In this study, the effects of SiO2 nanoparticles added to the electroless Ni-P coating were studied. The surface morphology, corrosion behavior, hardness and porosity of Ni-P-SiO2composite were investigated. The related microstructure was investigated through field emission scanning electron microscopy (FESEM) and the amount of SiO2 was examined by Energy Dispersive Analysis of X-ray (EDX). The corrosion behavior was evaluated through electrochemical impedance spectroscopy (EIS) and polarization techniques. The results illustrated that with increasing the quantity of the SiO2 nanoparticles, the corrosion rate decreased and the hardness increased.

  18. Microfluidic active mixers employing ultra-high aspect-ratio rare-earth magnetic nano-composite polymer artificial cilia

    International Nuclear Information System (INIS)

    Rahbar, Mona; Gray, Bonnie L; Shannon, Lesley

    2014-01-01

    We present a new micromixer based on highly magnetic, flexible, high aspect-ratio, artificial cilia that are fabricated as individual micromixer elements or in arrays for improved mixing performance. These new cilia enable high efficiency, fast mixing in a microchamber, and are controlled by small electromagnetic fields. The artificial cilia are fabricated using a new micromolding process for nano-composite polymers. Cilia fibers with aspect-ratios as high as 8:0.13 demonstrate the fabrication technique's capability in creating ultra-high aspect-ratio microstructures. Cilia, which are realized in polydimethylsiloxane doped with rare-earth magnetic powder, are magnetized to produce permanent magnetic structures with bidirectional deflection capabilities, making them highly suitable as mixers controlled by electromagnetic fields. Due to the high magnetization level of the polarized nano-composite polymer, we are able to use miniature electromagnets providing relatively small magnetic fields of 1.1 to 7 mT to actuate the cilia microstructures over a very wide motion range. Mixing performances of a single cilium, as well as different arrays of multiple cilia ranging from 2 to 8 per reaction chamber, are characterized and compared with passive diffusion mixing performance. The mixer cilia are actuated at different amplitudes and frequencies to optimize mixing performance. We demonstrate that more than 85% of the total volume of the reaction chamber is fully mixed after 3.5 min using a single cilium mixer at 7 mT compared with only 20% of the total volume mixed with passive diffusion. The time to achieve over 85% mixing is further reduced to 70 s using an array of eight cilia microstructures. The novel microfabrication technique and use of rare-earth permanently-magnetizable nano-composite polymers in mixer applications has not been reported elsewhere by other researchers. We further demonstrate improved mixing over other cilia micromixers as enabled by the high

  19. Graphene nano-devices and nano-composites for structural, thermal and sensing applications

    Science.gov (United States)

    Yavari, Fazel

    In this dissertation we have developed graphene-based nano-devices for applications in integrated circuits and gas sensors; as well as graphene-based nano-composites for applications in structures and thermal management. First, we have studied the bandgap of graphene for semiconductor applications. Graphene as a zero-bandgap material cannot be used in the semiconductor industry unless an effective method is developed to open the bandgap in this material. We have demonstrated that a bandgap of 0.206 eV can be opened in graphene by adsorption of water vapor molecules on its surface. Water molecules break the molecular symmetries of graphene resulting in a significant bandgap opening. We also illustrate that the lack of bandgap in graphene can be used to our advantage by making sensors that are able to detect low concentrations of gas molecules mixed in air. We have shown that 1-2 layers of graphene synthesized by chemical vapor deposition enables detection of trace amounts of NO 2 and NH3 in air at room temperature and atmospheric pressure. The gas species are detected by monitoring changes in electrical resistance of the graphene film due to gas adsorption. The sensor response time is inversely proportional to the gas concentration. Heating the film expels chemisorbed molecules from the graphene surface enabling reversible operation. The detection limits of ~100 parts-per-billion (ppb) for NO2 and ~500 ppb for NH3 obtained using this device are markedly superior to commercially available NO2 and NH3 detectors. This sensor is fabricated using individual graphene sheets that are exquisitely sensitive to the chemical environment. However, the fabrication and operation of devices that use individual nanostructures for sensing is complex, expensive and suffers from poor reliability due to contamination and large variability from sample-to-sample. To overcome these problems we have developed a gas sensor based on a porous 3D network of graphene sheets called graphene foam

  20. Effect of Addition of Colloidal Silica to Films of Polyimide, Polyvinylpyridine, Polystyrene, and Polymethylmethacrylate Nano-Composites

    Directory of Open Access Journals (Sweden)

    Soliman Abdalla

    2016-02-01

    Full Text Available Nano-composite films have been the subject of extensive work for developing the energy-storage efficiency of electrostatic capacitors. Factors such as polymer purity, nanoparticle size, and film morphology drastically affect the electrostatic efficiency of the dielectric material that forms the insulating film between the conductive electrodes of a capacitor. This in turn affects the energy storage performance of the capacitor. In the present work, we have studied the dielectric properties of four highly pure amorphous polymer films: polymethyl methacrylate (PMMA, polystyrene, polyimide and poly-4-vinylpyridine. Comparison between the dielectric properties of these polymers has revealed that the higher breakdown performance is a character of polyimide (PI and PMMA. Also, our experimental data shows that adding colloidal silica to PMMA and PI leads to a net decrease in the dielectric properties compared to the pure polymer.

  1. SYNTHESIS AND CORROSION PROTECTION BEHAVIOR OF EPOXYTiO2-MICACEOUS IRON OXIDE NANO - COMPOSITE COATING ON St-37

    Directory of Open Access Journals (Sweden)

    M. R. Khorram

    2016-03-01

    Full Text Available The micro layers micaceous iron oxide and nano-TiO 2 were incorporated into the epoxy resin by mechanical mixing and sonication process. Optical micrographs showed that the number and diameter size of nanoparticle agglomerates were decreased by sonication. The structure and composition of the nanocomposite was determined using transmission electron microscopy which showed the presence of dispersed nano-TiO 2 in the polymer matrix. The anticorrosive properties of the synthesized nano-composites coating were investigated using salt spray, electrochemical impedance spectroscopy and polarization measurement. The EIS results showed that coating resistance increased by addition of micaceous iron oxide micro layers and nano-TiO 2 particles to the epoxy coatings. It was observed that higher corrosion protection of nanocomposite coatings obtained by the addition of 3 %wt micaceous iron oxide and 4%wt nano-TiO 2 into epoxy resin.

  2. SiO2@FeSO4 nano composite: A recoverable nano-catalyst for eco-friendly synthesis oximes of carbonyl compounds

    Directory of Open Access Journals (Sweden)

    Mostafa Karimkoshteh

    2016-01-01

    Full Text Available Various aldoximes and ketoximes synthesis of corresponding aldehydes and ketones in the presence of SiO2@FeSO4 nano composite as recoverable nano catalyst and NH2OH·HCl. The SiO2@FeSO4 nano composite system was carried out between 10 to 15 min in oil bath (70-80 °C under solvent-free condition in excellent yields in addition this protocol can be used for industrial scales. This method offers some advantages in term of clean reaction conditions, easy work-up procedure, short reaction time, applied to convert α-diketones to α-diketoximes (as longer than other carbonyl compounds, α,β-unsaturated aldehydes and ketones to corresponding oximes and suppression of any side product. So we think that NH2OH•HCl/SiO2@FeSO4 nano composite system could be considered a new and useful addition to the present methodologies in this area. Structure of products and nano composite elucidation was carried out by 1H NMR, 13C NMR, FT-IR, scanning electron microscopy (SEM.

  3. Sintering of Cu–Al2O3 nano-composite powders produced by a thermochemical route

    Directory of Open Access Journals (Sweden)

    MARIJA KORAC

    2007-11-01

    Full Text Available This paper presents the synthesis of nano-composite Cu–Al2O3 powder by a thermochemical method and sintering, with a comparative analysis of the mechanical and electrical properties of the obtained solid samples. Nano-crystalline Cu–Al2O3 powders were produced by a thermochemical method through the following stages: spray-drying, oxidation of the precursor powder, reduction by hydrogen and homogenization. Characterization of powders included analytical electron microscopy (AEM coupled with energy dispersive spectroscopy (EDS, differenttial thermal and thermogravimetric (DTA–TGA analysis and X-ray diffraction (XRD analysis. The size of the produced powders was 20–50 nm, with a noticeable presence of agglomerates. The composite powders were characterized by a homogenous distribution of Al2O3 in a copper matrix. The powders were cold pressed at a pressure of 500 MPa and sintered in a hydrogen atmosphere under isothermal conditions in the temperature range from 800 to 900 °C for up to 120 min. Characterization of the Cu–Al2O3 sintered system included determination of the density, relative volume change, electrical and mechanical properties, examination of the microstructure by SEM and focused ion beam (FIB analysis, as well as by EDS. The obtained nano-composite, the structure of which was, with certain changes, presserved in the final structure, provided a sintered material with a homogenеous distribution of dispersoid in a copper matrix, with exceptional effects of reinforcement and an excellent combination of mechanical and electrical properties.

  4. In situ intercalative polymerization of poly (ε-caprolactone)/ 12-amino lauric acid-modified clay nano composites

    International Nuclear Information System (INIS)

    Reyes, Larry; Monserate, Juvy J.; Sumera, Florentino

    2013-01-01

    Polymer/layered silicate nano composites were prepared by in situ intercalative polymerization method from from ε-caprolactone (ε-CL) and 12-amino lauric acid modified montmorillonite (AMMT). The organo-modified clay was investigated for its capacity to facilitate ring-opening polymerization of ε-caprolactone within its silicate layers. The effect of varying the organo-modified clay loading (5%, 10% and 15% by weight) on the molecular weight of the poly (ε-caprolactone) (PCL) product was assessed by gel-permeation chromatography. The molecular weight of the polymer with different clay loadings ranged from ∼30,000 g/mo to ∼70,000 g/mol, where the 10% loading produced the highest molecular weight. Fourier Transform infrared (FTIR), and 1 H and 13 C Nuclear Magnetic Resonance (NMR) Spectroscopy were conducted to probe the composition of the polymer and the catalytic activity of AMMT to polymerize ε-CL. FTIR analyses showed two medium intensity and narrow CO-O stretching vibrations for the PCL products at around 1240 cm-1 and 1160 cm-1, which are attributed to ester skeletal backbone. 1 HNMR spectroscopic analysis revealed signals at 4.07 ppm and 3.66 ppm which can be attributed to εmethylene of caprolactone and methyl of ending ester group, respectively. The formation of the nano composites were assessed by X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM), XRD analyses showed a broadening and disappearance of diffraction peak of AMMT in the nana composite which may indicate the formation of the intercalated and partially exfoliated PCVL/AMMT nana composites. TEM observations corroborated the presence of intercalated and exfoliated layers of AMMT after polymerization. The present work demonstrates that AMMT can be used as an alternative g reen catalyst's for the production of biodegradable polymers, where the in situ intercalative polymerization was employed as a direct method of preparing polymer/layered silicates (author)

  5. Copper nano composites functionalized by bis-benzimidazole diamide ligand: Effect of size, co-anion dependent conductivity and band gap studies

    International Nuclear Information System (INIS)

    Singla, Manisha; Mohapatra, Subash Chandra; Ahmad, Sharif

    2012-01-01

    Copper (I) and copper (II) nano composites capped with a bis-benzimidazole diamide ligand were prepared by reverse micelle method and characterized using CHNS, FTIR, 1 H NMR, TEM and DLS studies. All particles were spherical ranging between 10 and 70 nm. They displayed a quasi reversible redox wave due to the Cu (II)/Cu (I) reduction process. The E g1 ′ values shift anodically as NO 3 − − − . Electrochemical HOMO and LUMO band gap (E g1 ′ ) for the nano composites were +1.80 (NO 3 − ), +2.80 (Cl − ) and +4.10 (SCN − ) eV, respectively. However, the optical band gap (E g1 ) for the nano composites was calculated from their absorption edges and lie between 1.77 and 4.13 eV. Fluorescence studies reveal that nano composites in themselves behave as an enhancer and quencher in respect to ligand, Quantum yield (φ) is varying from 0.008 to 0.02 photon. The activation energies range from 34 to 54 kJ mol −1 and are quite low in comparison to that of the free bis-benzimidazole diamide ligand (137 kJ mol −1 ). The lower activation energies further re-emphasize the nano size of these composites. At room temperature, the dc conductivity lies between 1 × 10 −4 –9.33 × 10 −4 S cm −1 [NO 3 − > SCN − > Cl − ] indicating them to be on the semiconductor insulator interface. The dielectric constant, dielectric loss and the ac conductivity were measured for all nano at room temperature and below the room temperature for the nano composite containing nitrate as co-anion. The conductivity was found to follow the correlated barrier hopping (CBH) mechanism; the exponent factor (s) varies from 0.5 to 1. -- Highlights: ► Nano composites of copper, capped by bis benzimidazole diamide ligand. ► Such copper nano composites have not been used in conductivity studies before. ► Conductance studies for these thus make this work unique. ► The dc conductivity of these composites is much higher than normal.

  6. Characterization of Ni–P–SiO{sub 2} nano-composite coating on magnesium

    Energy Technology Data Exchange (ETDEWEB)

    Sadreddini, S., E-mail: sina.sadreddini1986@gmail.com [Department of Materials Science and Engineering, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Salehi, Z. [Department of Chemical Science and Technology, Tor Vergata University, Rome (Italy); Rassaie, H. [Department of Materials Science and Engineering, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2015-01-01

    Highlights: • The enhancement of SiO{sub 2} nanoparticles in the bath up to 12.5 g/l, increased the amount of coating particles to 4.62 wt%. • Better corrosion resistance and lower porosity could be obtained by expansion prevention of corrosion cavity with deposition of nanoparticles in the coating. • Microhardness increases with increasing the SiO{sub 2} particles concentration. - Abstract: In this study, the effects of SiO{sub 2} nanoparticles added to the electroless Ni–P coating were studied. The surface morphology, corrosion behavior, hardness and porosity of Ni–P–SiO{sub 2}composite were investigated. The related microstructure was investigated through field emission scanning electron microscopy (FESEM) and the amount of SiO{sub 2} was examined by Energy Dispersive Analysis of X-ray (EDX). The corrosion behavior was evaluated through electrochemical impedance spectroscopy (EIS) and polarization techniques. The results illustrated that with increasing the quantity of the SiO{sub 2} nanoparticles, the corrosion rate decreased and the hardness increased.

  7. Characterization of Ni–P–SiO2 nano-composite coating on magnesium

    International Nuclear Information System (INIS)

    Sadreddini, S.; Salehi, Z.; Rassaie, H.

    2015-01-01

    Highlights: • The enhancement of SiO 2 nanoparticles in the bath up to 12.5 g/l, increased the amount of coating particles to 4.62 wt%. • Better corrosion resistance and lower porosity could be obtained by expansion prevention of corrosion cavity with deposition of nanoparticles in the coating. • Microhardness increases with increasing the SiO 2 particles concentration. - Abstract: In this study, the effects of SiO 2 nanoparticles added to the electroless Ni–P coating were studied. The surface morphology, corrosion behavior, hardness and porosity of Ni–P–SiO 2 composite were investigated. The related microstructure was investigated through field emission scanning electron microscopy (FESEM) and the amount of SiO 2 was examined by Energy Dispersive Analysis of X-ray (EDX). The corrosion behavior was evaluated through electrochemical impedance spectroscopy (EIS) and polarization techniques. The results illustrated that with increasing the quantity of the SiO 2 nanoparticles, the corrosion rate decreased and the hardness increased

  8. Gamma radiation effects on nano composites of Ag nanoparticles in Zn O matrices; Efectos de la radiacion gamma en nanocompositos de nanoparticulas de Ag en matrices de ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Villasenor C, L. S.

    2015-07-01

    The study of gamma radiation effects in nano composites of silver nanoparticles in a Zn O matrix has been performed in this work. First, silver nanoparticles (AgNPs) were synthesized by colloidal methods, with two different mean average sizes, 48 nm and 24 nm respectively. These nanoparticles were characterized by transmission electron microscopy (Tem) and UV-Vis spectroscopy (UV-Vis). Then, with the synthesized AgNPs, nano composites in a matrix of Zn O were prepared. The first nano composite was prepared with the 48 nm AgNPs at 9.5 weight % of silver (Ag) and the second nano composite with the 24 nm nanoparticles at 1.0 weight % of Ag. Both nano composites were analyzed by scanning electron microscopy (Sem). The formation of the Zn O phase in the nano composite was corroborated through X-ray diffraction analysis. It was observed that the presence of AgNPs during the formation of the AgNPs/Zn O nano composite modified the size and morphology of the structures obtained compared to those of the pure Zn O without nanoparticles, however both exhibit a radial structure. Then, the nano composite at 9.5 weight % of Ag was irradiated with gamma rays at doses of 1, 20 and 50 kGy. Samples were analyzed by Sem and the Bet technique, before and after being irradiated, in order to determine the effect of gamma radiation in the morphology, porosity and surface area of the studied material. Even when there are changes in porosity and Surface area, this difference is not very significant for some applications, however it will have to be considered during the design of a specific application of the nano composites. On the other hand, no morphology modifications were identified on the samples irradiated at the studied doses, with the electron microscopy techniques used. (Author)

  9. Nano-composite powders Ag-SnO2 prepared by reactive milling sintering and microstructural evolution

    International Nuclear Information System (INIS)

    Lorrain, Nathalie

    2000-01-01

    This work aims at controlling the synthesis and the sintering of nano-composite powders Ag-SnO 2 in order to obtain a dense and nano-structured material for electrical contact as a substitute of the toxic compound Ag - CdO. The powder is prepared by reactive milling from silver oxide (Ag 2 O) and silver bronze (Ag 3 Sn) powders. This process leads to a fine dispersion of silver and tin oxide nanometer sized particles. We first studied the mechanisms of reaction promoted by milling in vacuum and in air. A two-stage oxidation of tin in Ag 3 Sn occurs: during forced contact with Ag 2 O, tin oxidises in SnO, then in SnO 2 . In air, gaseous oxygen also participates to the oxidation of tin in SnO 2 but the reaction is slower because of the formation of silver carbonates from a reaction of Ag 2 O with CO 2 .Then the sintering behaviour of the nano-composite powder as a function of the compacting pressure and of the heating rate has been studied. We show: (i) a diffusion of pure silver towards porosity and free surfaces (exo-diffusion) which destroys the nano-structure and (ii) a severe de-densification. We show that the origin of these phenomena is due to carbonates on to the Ag 2 O starting powder, which are incorporated, in the milled Ag-SnO 2 powder in course of milling; during sintering, decomposition gases generate internal stresses. Low stresses lead to a diffusional creep with exo-diffusion whereas high stresses induce an intensive de-densification by local plastic deformation but no exo-diffusion. A modelling shows that exo-diffusion is limited by heating very quickly a strongly compacted powder that contains a high quantity of carbonates. The experimental results confirm the predictions of the model. Finally, we propose solutions allowing a full densification and a process for decreasing the tin oxide concentration. (author) [fr

  10. Polyethylene ionomer-based nano-composite foams prepared by a batch process and MuCell injection molding

    International Nuclear Information System (INIS)

    Hayashi, Hidetomo; Mori, Tomoki; Okamoto, Masami; Yamasaki, Satoshi; Hayami, Hiroshi

    2010-01-01

    To understand the correlation between foamability and melt rheology of polyethylene-based ionomers having different degrees of the neutralization and corresponding nano-composites, we have conducted the foam processing via a batch process in an autoclave and microcellular foam injection molding (FIM) process using the MuCell technology. We have discussed the obtainable morphological properties in both foaming processes. All cellular structures were investigated by using field emission scanning electron microscopy. The competitive phenomenon between the cell nucleation and the cell growth including the coalescence of cell was discussed in light of the interfacial energy and the relaxation rate as revealed by the modified classical nucleation theory and rheological measurement, respectively. The FIM process led to the opposite behavior in the cell growth and coalescence of cell as compared with that of the batch process, where the ionic cross-linked structure has significant contribution to retard the cell growth and coalescence of cell. The mechanical properties of the structural foams obtained by FIM process were discussed.

  11. Design of thermoelectrically highly efficient Heusler compounds using phase separations and nano-composites under an economic point of view

    Science.gov (United States)

    Balke, Benjamin

    Half-Heusler (HH) compounds are one of the most promising candidates for thermoelectric materials for automotive and industrial waste heat recovery applications. In this talk, I will give an overview about our recent investigations of phase separations in HH thermoelectrics, focusing on the ternary system TiNiSn-ZrNiSn-HfNiSn. I will show how we adapted this knowledge to design a p-type HH compound which exhibits a ZT that is increased by 130% compared to the best published bulk p-type Heusler. I will also present how we used the phase separation to design thermoelectric highly efficient nano-composites of different single-phase materials. Since the price for Hafnium doubled within the last year, our research focused on the design of HH compounds without Hafnium. I will present a very recent calculation on ZT per Euro and efficiency per Euro for various materials followed by our latest very promising results for n-type Heusler compunds without Hafnium resulting in 20 times higher ZT/Euro values. These results strongly underline the importance of phase separations as a powerful tool for designing highly efficient materials for thermoelectric applications that fulfill the industrial demands for a thermoelectric converter. The author gratefully acknowledges financial support by the thermoHEUSLER2 Project (Project No. 19U15006F) of the German Federal Ministry of Economics and Technology (BMWi).

  12. High photocatalytic degradation activity of the polyvinyl chloride (PVC)-vitamin C (VC)-TiO{sub 2} nano-composite film

    Energy Technology Data Exchange (ETDEWEB)

    Yang Changjun; Gong Chuqing; Peng Tianyou [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Deng Kejian [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, South-Central University for Nationalities, Wuhan 430074 (China); Zan Ling, E-mail: irlab@whu.edu.cn [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China)

    2010-06-15

    A novel photodegradable polyvinyl chloride (PVC)-vitamin C (VC)-TiO{sub 2} nano-composite film was prepared by embedding VC modified nano-TiO{sub 2} photocatalyst into the commercial PVC plastic. The solid-phase photocatalytic degradation behavior of PVC-VC-TiO{sub 2} nano-composite film under UV light irradiation was investigated and compared with those of the PVC-TiO{sub 2} film and the pure PVC film, with the aid of UV-Vis spectroscopy, scanning electron microscopy (SEM), weight loss monitoring, and X-ray diffraction spectra (XRD). The results show that PVC-VC-TiO{sub 2} nano-composite film has a high photocatalytic activity; the photocatalytic degradation rate of it is two times higher than that of PVC-TiO{sub 2} film and fifteen times higher than that of pure PVC film. The optimal mass ratio of VC to TiO{sub 2} is found to be 0.5. The mechanism of enhancing photocatalytic activity is attributed to the formation of a Ti{sup IV}-VC charge-transfer complex with five-member chelate ring structure and a rapid photogenerated charge separation is thus achieved.

  13. Corrosion Behavior and Microhardness of Ni-P-SiO2-Al2O3 Nano-composite Coatings on Magnesium Alloy

    Science.gov (United States)

    Sadreddini, S.; Rahemi Ardakani, S.; Rassaee, H.

    2017-05-01

    In the present work, nano-composites of Ni-P-SiO2-Al2O3 were coated on AZ91HP magnesium alloy. The surface morphology of the nano-composite coating was studied by field emission scanning electron microscopy (FESEM). The amount of SiO2 in the coating was determined by energy-dispersive analysis of x-ray (EDX), and the crystalline structure of the coating was examined by x-ray diffractometer (XRD). All the experiments concerning the corrosion behavior of the coating carried out in 3.5 wt.% NaCl solution and evaluated by electrochemical impedance spectroscopy (EIS) and polarization technique. The results showed that an incorporation of SiO2 and Al2O3 in Ni-P coating at the SiO2 concentration of 10 g/Land 14 g/LAl2O3 led to the lowest corrosion rate ( i corr = 1.3 µA/cm2), the most positive E corr and maximum microhardness (496 VH). Furthermore, Ni-P-SiO2-Al2O3 nano-composite coating possesses less porosity than that in Ni-P coating, resulting in improving corrosion resistance.

  14. Synthesis of LiFePO4/Graphene Nano composite and Its Electrochemical Properties as Cathode Material for Li-Ion Batteries

    International Nuclear Information System (INIS)

    Ma, X.; Chen, G.; Liu, Q.; Zeng, G.; Wu, T.

    2014-01-01

    LiFePO 4 /graphene nano composite was successfully synthesized by rheological phase method and its electrochemical properties as the cathode materials for lithium ion batteries were measured. As the iron source in the synthesis, FeOOH nano rods anchored on graphene were first synthesized. The FeOOH nano rods precursors and the final LiFePO 4 /graphene nano composite products were characterized by XRD, SEM, and TEM. While the FeOOH precursors were nano rods with 5-10 nm in diameter and 10-50 nm in length, the LiFePO 4 were nanoparticles with 20-100 nm in size. Compared with the electrochemical properties of LiFePO 4 particles without graphene nano sheets, it is clear that the graphene nano sheets can improve the performances of LiFePO 4 as the cathode material for lithium ion batteries. The as-synthesized LiFePO 4 /graphene nano composite showed high capacities and good cyclabilities. When measured at room temperature and at the rate of 0.1 C (1 C = 170 mA g -1 ), the composite showed a discharge capacity of 156 mA h g -1 in the first cycle and a capacity retention of 96% after 15 cycles. The improved performances of the composite are believed to be the result of the three-dimensional conducting network formed by the flexible and planar graphene nano sheets.

  15. High photocatalytic degradation activity of the polyvinyl chloride (PVC)-vitamin C (VC)-TiO2 nano-composite film

    International Nuclear Information System (INIS)

    Yang Changjun; Gong Chuqing; Peng Tianyou; Deng Kejian; Zan Ling

    2010-01-01

    A novel photodegradable polyvinyl chloride (PVC)-vitamin C (VC)-TiO 2 nano-composite film was prepared by embedding VC modified nano-TiO 2 photocatalyst into the commercial PVC plastic. The solid-phase photocatalytic degradation behavior of PVC-VC-TiO 2 nano-composite film under UV light irradiation was investigated and compared with those of the PVC-TiO 2 film and the pure PVC film, with the aid of UV-Vis spectroscopy, scanning electron microscopy (SEM), weight loss monitoring, and X-ray diffraction spectra (XRD). The results show that PVC-VC-TiO 2 nano-composite film has a high photocatalytic activity; the photocatalytic degradation rate of it is two times higher than that of PVC-TiO 2 film and fifteen times higher than that of pure PVC film. The optimal mass ratio of VC to TiO 2 is found to be 0.5. The mechanism of enhancing photocatalytic activity is attributed to the formation of a Ti IV -VC charge-transfer complex with five-member chelate ring structure and a rapid photogenerated charge separation is thus achieved.

  16. Fabrication of CDs/CdS-TiO2 ternary nano-composites for photocatalytic degradation of benzene and toluene under visible light irradiation

    Science.gov (United States)

    Wang, Meng; Hua, Jianhao; Yang, Yaling

    2018-06-01

    An efficient cadmium sulfide quantum-dots (CdS QDs) and carbon dots (CDs) modified TiO2 photocatalyst (CdS/CDs-TiO2) was successfully fabricated. The as-prepared ternary nano-composites simultaneously improved the photo-corrosion of CdS and amplified its photocatalytic activity. The introduction of CdS QDs and CDs could enhance more absorbance of light, prevent the undesirable electron/hole recombination, and promote charge separation, which was important for the continuous formation of rad OH and rad O2- radicals. When the optimal mass ratio of CdS QDs to CDs was 3:1, above 90% degradation efficiencies were achieved for benzene within 1 h and toluene in 2 h, while that of pure TiO2 (P25), CdS QDs-TiO2, CDs-TiO2 nano-composites was around 15%. Owing to the symmetric structure and conjugation of methyl with benzene ring, the degradation of toluene was more difficult than benzene to carry on. The new fabricated nano-composites showed good prospective application of cleaning up refractory pollutants and the resource utilization.

  17. Dielectric relaxation and ac conduction in γ-irradiated UHMWPE/MWCNTs nano composites: Impedance spectroscopy analysis

    International Nuclear Information System (INIS)

    Maqbool, Syed Asad; Mehmood, Malik Sajjad; Mukhtar, Saqlain Saqib; Baluch, Mansoor A.; Khan, Shamim; Yasin, Tariq; Khan, Yaqoob

    2017-01-01

    The dielectric behavior of γ-irradiated ultra-high molecular weight polyethylene (UHMWPE) and its nano composites (NCs) with γ-ray modified multi wall carbon nano tubes (γ-MWCNTs) and MWCNTs had been studied using impedance spectroscopy. The study had been carried out in the frequency range of 20–2 MHz at room temperature. All samples (pure and NCs) were prepared in the form of sheets and irradiated with γ-dose of 50 kGy and 100 kGy, respectively. The comprehensive analysis of results revealed that resistivity of UHMWPE for conduction decreased on irradiation and incorporation of MWCNTs (whether γ ray modified or un-modified) due to the radiation induced damage and conductive networks induced by MWCNTs. At low frequency range a significant increase in the dielectric constant had been observed because of irradiation and addition of MWNCTs. The trend of loss tangent and ac conductivity for each investigated sample depended on resistivity offered and had a decreasing trend as a function of frequency. Moreover, dissipation factor increased with the incorporation of MWNCTs and irradiation from 0.12 to 0.22. In addition to this, non-frequency dependent static dielectric constant was also found to increase with irradiation and incorporation of MWCNTs. The relaxation time was found to increase from 1.2 to 4.3 ms due to hindrance offered by radiation induced mutual cross linking of PE chains and polymer-MWNCTs bindings. - Highlights: • The resistivity for conduction in pristine UHMWPE is decreased with γ-irradiation. • Conduction in PE/MWCNTs nanocomposites increased due to MWCNTs addition. • Static dielectric constant of UHMWPE increased with γ-irradiation. • Static dielectric constant of UHMWPE increased due to MWCNTs incorporation.

  18. An in vivo evaluation of PLLA/PLLA-gHA nano-composite for internal fixation of mandibular bone fractures.

    Science.gov (United States)

    Peng, Weihai; Zheng, Wei; Shi, Kai; Wang, Wangshu; Shao, Ying; Zhang, Duo

    2015-11-09

    Internal fixation of bone fractures using biodegradable poly(L-lactic-acid) (PLLA)-based materials has attracted the attention of many researchers. In the present study, 36 male beagle dogs were randomly assigned to two groups: PLLA/PLLA-gHA (PLLA-grafted hydroxyapatite) group and PLLA group. PLLA/PLLA-gHA and PLLA plates were embedded in the muscular bags of the erector spinae and also implanted to fix mandibular bone fractures in respective groups. At 1, 2, 3, 6, 9, and 12 months postoperatively, the PLLA/PLLA-gHA and PLLA plates were evaluated by adsorption and degradation tests, and the mandibles were examined through radiographic analysis, biomechanical testing, and histological analysis. The PLLA/PLLA-gHA plates were non-transparent and showed a creamy white color, and the PLLA plates were transparent and faint yellow in color. At all time points following surgery, adsorption and degradation of the PLLA/PLLA-gHA plates were significantly less than those of the PLLA plates, and the lateral and longitudinal bending strengths of the surgically treated mandibles of the beagle dogs in the PLLA/PLLA-gHA group were significantly greater than those of the PLLA group and reached almost the value of intact mandibles at 12 months postoperatively. Additionally, relatively rapid bone healing was observed in the PLLA/PLLA-gHA group with the formation of new lamellar bone tissues at 12 months after the surgery. The PLLA/PLLA-gHA nano-composite can be employed as a biodegradable material for internal fixation of mandibular bone fractures.

  19. An in vivo evaluation of PLLA/PLLA-gHA nano-composite for internal fixation of mandibular bone fractures

    International Nuclear Information System (INIS)

    Peng, Weihai; Shi, Kai; Wang, Wangshu; Shao, Ying; Zhang, Duo; Zheng, Wei

    2015-01-01

    Internal fixation of bone fractures using biodegradable poly(L-lactic-acid) (PLLA)-based materials has attracted the attention of many researchers. In the present study, 36 male beagle dogs were randomly assigned to two groups: PLLA/PLLA-gHA (PLLA-grafted hydroxyapatite) group and PLLA group. PLLA/PLLA-gHA and PLLA plates were embedded in the muscular bags of the erector spinae and also implanted to fix mandibular bone fractures in respective groups. At 1, 2, 3, 6, 9, and 12 months postoperatively, the PLLA/PLLA-gHA and PLLA plates were evaluated by adsorption and degradation tests, and the mandibles were examined through radiographic analysis, biomechanical testing, and histological analysis. The PLLA/PLLA-gHA plates were non-transparent and showed a creamy white color, and the PLLA plates were transparent and faint yellow in color. At all time points following surgery, adsorption and degradation of the PLLA/PLLA-gHA plates were significantly less than those of the PLLA plates, and the lateral and longitudinal bending strengths of the surgically treated mandibles of the beagle dogs in the PLLA/PLLA-gHA group were significantly greater than those of the PLLA group and reached almost the value of intact mandibles at 12 months postoperatively. Additionally, relatively rapid bone healing was observed in the PLLA/PLLA-gHA group with the formation of new lamellar bone tissues at 12 months after the surgery. The PLLA/PLLA-gHA nano-composite can be employed as a biodegradable material for internal fixation of mandibular bone fractures. (paper)

  20. Creatinine and urea biosensors based on a novel ammonium ion-selective copper-polyaniline nano-composite.

    Science.gov (United States)

    Zhybak, M; Beni, V; Vagin, M Y; Dempsey, E; Turner, A P F; Korpan, Y

    2016-03-15

    The use of a novel ammonium ion-specific copper-polyaniline nano-composite as transducer for hydrolase-based biosensors is proposed. In this work, a combination of creatinine deaminase and urease has been chosen as a model system to demonstrate the construction of urea and creatinine biosensors to illustrate the principle. Immobilisation of enzymes was shown to be a crucial step in the development of the biosensors; the use of glycerol and lactitol as stabilisers resulted in a significant improvement, especially in the case of the creatinine, of the operational stability of the biosensors (from few hours to at least 3 days). The developed biosensors exhibited high selectivity towards creatinine and urea. The sensitivity was found to be 85 ± 3.4 mAM(-1)cm(-2) for the creatinine biosensor and 112 ± 3.36 mAM(-1)cm(-2) for the urea biosensor, with apparent Michaelis-Menten constants (KM,app), obtained from the creatinine and urea calibration curves, of 0.163 mM for creatinine deaminase and 0.139 mM for urease, respectively. The biosensors responded linearly over the concentration range 1-125 µM, with a limit of detection of 0.5 µM and a response time of 15s. The performance of the biosensors in a real sample matrix, serum, was evaluated and a good correlation with standard spectrophotometric clinical laboratory techniques was found. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. FeOOH-loaded MnO2 nano-composite: An efficient emergency material for thallium pollution incident.

    Science.gov (United States)

    Chen, Meiqing; Wu, Pingxiao; Yu, Langfeng; Liu, Shuai; Ruan, Bo; Hu, Haihui; Zhu, Nengwu; Lin, Zhang

    2017-05-01

    A FeOOH-loaded MnO 2 nano-composite was developed as an emergency material for Tl(I) pollution incident. Structural characterizations showed that FeOOH successfully loaded onto MnO 2 , the nanosheet-flower structure and high surface area (191 m 2  g -1 ) of material contributed to the excellent performance for Tl(I) removal. FeOOH-loaded MnO 2 with a Fe/Mn molar ratio of 1:2 exhibited a noticeable enhanced capacity for Tl(I) removal compared to that of pure MnO 2 . The outstanding performance for Tl(I) removal involves in extremely high efficiency (achieved equilibrium and drinking water standard within 4 min) and the large maximum adsorption capacity (450 mg g -1 ). Both the control-experiment and XPS characterization proved that the removal mechanism of Tl(I) on FeOOH-loaded MnO 2 included adsorption and oxidation: the oxidation of MnO 2 played an important role for Tl(I) removal, and the adsorption of FeOOH loaded on MnO 2 enhanced Tl(I) purification at the same time. In-depth purification of Tl(I) had reach drinking water standards (0.1 μg L -1 ) at pH above 7, and there wasn't security risk produced from the dissolution of Mn 2+ and Fe 2+ . Moreover, the as-prepared material could be utilized as a recyclable adsorbent regenerated by using NaOH-NaClO binary solution. Therefore, the synthesized FeOOH-loaded MnO 2 in this study has the potential to be applied as an emergency material for thallium pollution incident. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. One-step solution combustion synthesis of Fe{sub 2}O{sub 3}/C nano-composites as anode materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li, Peiyang; Deng, Jiachun; Li, Ying [Nano-Energy Inorganic Materials Laboratory, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Liang, Wei, E-mail: liangwei@tyut.edu.cn [Nano-Energy Inorganic Materials Laboratory, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Wang, Kun [Nano-Energy Inorganic Materials Laboratory, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Kang, Litao, E-mail: kangltxy@gmail.com [Nano-Energy Inorganic Materials Laboratory, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Zeng, Shaozhong; Yin, Shanhui; Zhao, Zhigang [Chery Automobile Co. Ltd., Wuhu 241006 (China); Liu, Xuguang; Yang, Yongzhen [College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Gao, Feng [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China)

    2014-03-25

    Highlights: • Fe{sub 2}O{sub 3}/C composite anode materials were prepared by a solution combustion process. • The carbon content could be adjusted by regulating the ratio of oxidizer/fuel. • The Fe{sub 2}O{sub 3}/C composite showed capacity 470 mA h g{sup −1} at the 80th cycle at 125 mA g{sup −1}. -- Abstract: This article describes a one-step solution combustion route (within 30 min at 350 °C in air) to prepare Fe{sub 2}O{sub 3} anode materials for lithium ion batteries (LIBs) from Fe(NO{sub 3}){sub 3}⋅9H{sub 2}O solution with citric acid. XRD, SEM-EDX and TEM showed that the product consisted a mixture of nano-sized α-Fe{sub 2}O{sub 3} and γ-Fe{sub 2}O{sub 3} crystals that agglomerated into porous particles. Significantly, in situ formed carbon could be introduced into the product (i.e., Fe{sub 2}O{sub 3}/C nano-composites) by simply increasing the dosage of citric acid in the precursor solution. The as-prepared Fe{sub 2}O{sub 3}/C nano-composite exhibited high reversible capacities of 470 and 419 mA h g{sup −1} at the 80th and 200th cycles with a current density of 125 mA g{sup −1}, which are much higher than those of counterparts without carbon (i.e., Fe{sub 2}O{sub 3} nano-particles). Comparison experiments correlated with the performance improvement of Fe{sub 2}O{sub 3}/C nano-composites with in situ formed carbon, well-developed mesopores and relatively high specific surface areas.

  3. Characterizing reactive oxygen generation and bacterial inactivation by a zerovalent iron-fullerene nano-composite device at neutral pH under UV-A illumination

    International Nuclear Information System (INIS)

    Erdim, Esra; Badireddy, Appala Raju; Wiesner, Mark R.

    2015-01-01

    Highlights: • We synthesized a novel ZVI/nC 60 nano-composite device for multi-ROS generation. • O 2 · − (UV-A independent) and 1 O 2 (UV-A dependent) are generated at neutral pH. • At low Fe concentration, ZVI/nC 60 device is a better ROS generator than ZVI alone. • C 60 mediates electron transfer from ZVI surface to dissolved O 2 to produce O 2 · − . • Bacteria are rapidly inactivated by O 2 · − even at low ZVI/nC 60 ratio. - Abstract: A nano-composite device composed of nano-scale zerovalent iron (ZVI) and C 60 fullerene aggregates (ZVI/nC 60 ) was produced via a rapid nucleation method. The device was conceived to deliver reactive oxygen species (ROS) generated by photosensitization and/or electron transfer to targeted contaminants, including waterborne pathogens under neutral pH conditions. Certain variations of the nano-composite were fabricated differing in the amounts of (1) ZVI (0.1 mM and 2 mM) but not nC 60 (2.5 mg-C/L), and (2) nC 60 (0–25 mg-C/L) but not ZVI (0.1 mM). The generation of ROS by the ZVI/nC 60 nano-composites and ZVI nanoparticles was quantified using organic probe compounds. 0.1 mM ZVI/2.5 mg-C/L C 60 generated 3.74-fold higher O 2 · − concentration and also resulted in an additional 2-log inactivation of Pseudomonas aeruginosa when compared to 0.1 mM ZVI (3-log inactivation). 2 mM ZVI/2.5 mg-C/L nC 60 showed negligible improvement over 2 mM ZVI in terms of O 2 · − generation or inactivation. Further, incremental amounts of nC 60 in the range of 0–25 mg-C/L in 0.1 mM ZVI/nC 60 led to increased O 2 · − concentration, independent of UV-A. This study demonstrates that ZVI/nC 60 device delivers (1) enhanced O 2 · − with nC 60 as a mediator for electron transfer, and (2) 1 O 2 (only under UV-A illumination) at neutral pH conditions

  4. A comparative study of gelatin and starch-based nano-composite films modified by nano-cellulose and chitosan for food packaging applications.

    Science.gov (United States)

    Noorbakhsh-Soltani, S M; Zerafat, M M; Sabbaghi, S

    2018-06-01

    Environmental concerns have led to extensive research for replacing polymer-based food packaging with bio-nano-composites. In this study, incorporation of nano-cellulose into gelatin and starch matrices is investigated for this purpose. Chitosan is used to improve mechanical, anti-fungal and waterproof properties. Experiments are designed and analyzed using response surface methodology. Nano-Cellulose is synthesized via acid hydrolysis and incorporated in base matrices through wet processing. Also, tensile strength test, food preservation, transparency in visible and UV and water contact angle are performed on the nano-composite films. DSC/TGA and air permeability tests are also performed on the optimal films. The results show that increasing nano-cellulose composition to 10% leads to increase the tensile strength at break to 8121 MN/m 2 and decrease the elongation at break. Also, increasing chitosan composition from 5% to 30% can enhance food preservation up to 15 days. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Effect of high energy electron beam (10 MeV) on specific heat capacity of low-density polyethylene/hydroxyapatite nano-composite

    Energy Technology Data Exchange (ETDEWEB)

    Soltani, Z., E-mail: zhr_soltani@yahoo.com [Health Physics and Radiation Dosimetry Research Laboratory, Department of Energy Engineering and Physics, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Ziaie, F. [Radiation Application Research School, Nuclear Science & Technology Research Institute, Tehran (Iran, Islamic Republic of); Ghaffari, M. [Polymer Group, Golestan University, Golestan (Iran, Islamic Republic of); Beigzadeh, A.M. [Radiation Application Research School, Nuclear Science & Technology Research Institute, Tehran (Iran, Islamic Republic of)

    2017-02-01

    In the present work, thermal properties of low density polyethylene (LDPE) and its nano composites are investigated. For this purpose LDPE reinforced with different weight percents of hydroxyapatite (HAP) powder which was synthesized via hydrolysis method are produced. The samples were irradiated with 10 MeV electron beam at doses of 75 to 250 kGy. Specific heat capacity measurement have been carried out at different temperatures, i.e. 25, 50, 75 and 100 °C using modulated temperature differential scanning calorimetry (MTDSC) apparatus and the effect of three parameters include of temperature, irradiation dose and the amount of HAP nano particles as additives on the specific heat capacity of PE/HAP have been investigated precisely. The MTDSC results indicate that the specific heat capacity have decreased by addition of nano sized HAP as reinforcement for LDPE. On the other hand, the effect of radiation dose is reduction in the specific heat capacity in all materials including LDPE and its nano composites. The HAP nano particles along with cross-link junctions due to radiation restrain the movement of the polymer chains in the vicinity of each particle and improve the immobility of polymer chains and consequently lead to reduction in specific heat capacity. Also, the obtained results confirm that the radiation effect on the specific heat capacity is more efficient than the reinforcing effect of nano-sized hydroxyapatite.

  6. Silane effects on the surface morphology and abrasion resistance of transparent SiO2/UV-curable resin nano-composites

    International Nuclear Information System (INIS)

    Hsiang, Hsing-I.; Chang, Yu-Lun; Chen, Chi-Yu; Yen, Fu-Su

    2011-01-01

    Transparent ultraviolet curable nano-composite coatings consisting of nano-sized SiO 2 and acrylate resin have been developed to improve the abrasion resistance of organic polymers. The nano-sized SiO 2 particles were surface-modified using various amounts of 3-methacryloxypropyltrimethoxysilane. The 3-methacryloxypropyltrimethoxysilane concentration effects on the surface morphology and abrasion resistance of the transparent SiO 2 /ultraviolet-curable resin nano-composites were investigated using scanning electron microscopy, atomic force microscopy, and ultraviolet-visible spectrophotometer. The results showed that as the 3-methacryloxypropyltrimethoxysilane/SiO 2 weight ratio increased from 0.2 to 0.6, the dispersion, compatibility and cross-linking density between the 3-methacryloxypropyltrimethoxysilane-modified SiO 2 particles and acrylate resin were improved, leading to an increase in abrasion resistance. However, as the 3-methacryloxypropyltrimethoxysilane/SiO 2 weight ratio was increased to 1.5, the additional 3-methacryloxypropyltrimethoxysilane may exceed that needed to fill the pores with the probability of SiO 2 nano-particles existing on the coating surface was lower than that for samples with a 3-methacryloxypropyltrimethoxysilane/SiO 2 weight ratio of 0.6. This produced a decrease in abrasion resistance.

  7. Preparation of EVA/silica nano composites characterized with solid state nuclear magnetic resonance; Obtencao de nanocomposito de EVA/SILICA e caracterizacao por ressonancia magnetica nuclear no estado solido

    Energy Technology Data Exchange (ETDEWEB)

    Passos, Adriano A; Tavares, Maria I.B.; Neto, Roberto C.P.; Moreira, Leonardo A; Ferreira, Antonio G., E-mail: mibt@ima.ufrj.br [Centro de Tecnologia, Instituto de Macromoleculas Professora Eloisa Mano, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil)

    2011-07-01

    Nano composites of poly(ethylene-co-vinyl acetate)/silica (SiO{sub 2}) with dimensions of ca. 40 nm were prepared via solution intercalation employing chloroform as a solvent. They were mainly characterized with nuclear magnetic resonance spectroscopy (NMR) employing carbon-13 (polymeric matrix), silicon-29 (nanoparticles) and through the determination of the proton spin-lattice relaxation time in the rotating frame (T{sub 1{rho}H}) (polymer matrix). From the NMR results it was inferred that up to 5% of silica in mass a well dispersed nano composite was obtained, owing to a strong interaction between silica and the EVA matrix. (author)

  8. Solvent-Mediated Eco-Friendly Synthesis and Characterization of Monodispersed Bimetallic Ag/Pd Nano composites for Sensing and Raman Scattering Applications

    International Nuclear Information System (INIS)

    Sathiyadevi, G.; Loganathan, B.; Karthikeyan, B.; Karthikeyan, B.

    2014-01-01

    The solvent-mediated eco-friendly monodispersed Ag/Pd bimetallic nano composites (BNCs) having thick core and thin shell have been prepared through novel green chemical solvent reduction method. Reducing solvent, dimethyl formamide (DMF) is employed for the controlled green synthesis. Characterization of the synthesized Ag/Pd BNCs has been done by x-ray diffraction (XRD) studies, high-resolution scanning electron microscopy (HR-SEM), energy-dispersive X-ray analysis (EDX), and high-resolution transmission electron microscopy (HR-TEM) with selected area electron diffraction (SAED) pattern. The nature of the interaction of L-cysteine with Ag/Pd BNCs has been studied by using surface plasmon spectroscopy, Fourier transform-infrared spectroscopy (FT-IR), cyclic voltammetry (CV), and theoretical methods.

  9. Microstructure, mechanical response and fractography of AZ91E/Al2O3 (p nano composite fabricated by semi solid stir casting method

    Directory of Open Access Journals (Sweden)

    Sameer Kumar D.

    2017-03-01

    Full Text Available The present study confers to the fabrication and its characterization of magnesium alloy (AZ91E based nano composites with nano Al2O3 particulate reinforcements. A novel Semi Solid stir casting technique was adopted for the fabrication of the composite. An average particle size of 50 nm was used as reinforcement to disperse in matrix. The effects of change in weight fraction of reinforcements on the distribution of particles, particle–matrix interfacial reactions, physical as well as mechanical properties were reported. The SEM and EDS analysis has shown the uniform distribution of particles in the composite along with the presence of elements. The mechanical properties of reinforced and unreinforced composite were evaluated and presented. Fractography of tensile specimens was also discussed.

  10. Microstructures and mechanical properties of Al/Al2O3 surface nano-composite layer produced by friction stir processing

    International Nuclear Information System (INIS)

    Shafiei-Zarghani, A.; Kashani-Bozorg, S.F.; Zarei-Hanzaki, A.

    2009-01-01

    In this study, a new processing technique, friction stir processing (FSP) was attempted to incorporate nano-sized Al 2 O 3 into 6082 aluminum alloy to form particulate composite surface layer. Samples were subjected to various numbers of FSP passes from one to four, with and without Al 2 O 3 powder. Microstructural observations were carried out by employing optical and scanning electron microscopy (SEM) of the cross sections both parallel and perpendicular to the tool traverse direction. Mechanical properties include microhardness and wear resistance, were evaluated in detail. The results show that the increasing in number of FSP passes causes a more uniform in distribution of nano-sized alumina particles. The microhardness of the surface improves by three times as compared to that of the as-received Al alloy. A significant improvement in wear resistance in the nano-composite surfaced Al is observed as compared to the as-received Al

  11. Room-temperature solution-processed and metal oxide-free nano-composite for the flexible transparent bottom electrode of perovskite solar cells

    Science.gov (United States)

    Lu, Haifei; Sun, Jingsong; Zhang, Hong; Lu, Shunmian; Choy, Wallace C. H.

    2016-03-01

    The exploration of low-temperature and solution-processed charge transporting and collecting layers can promote the development of low-cost and large-scale perovskite solar cells (PVSCs) through an all solution process. Here, we propose a room-temperature solution-processed and metal oxide-free nano-composite composed of a silver nano-network and graphene oxide (GO) flawless film for the transparent bottom electrode of a PVSC. Our experimental results show that the amount of GO flakes play a critical role in forming the flawless anti-corrosive barrier in the silver nano-network through a self-assembly approach under ambient atmosphere, which can effectively prevent the penetration of liquid or gaseous halides and their corrosion against the silver nano-network underneath. Importantly, we simultaneously achieve good work function alignment and surface wetting properties for a practical bottom electrode by controlling the degree of reduction of GO flakes. Finally, flexible PVSC adopting the room-temperature and solution-processed nano-composite as the flexible transparent bottom electrode has been demonstrated on a polyethylene terephthalate (PET) substrate. As a consequence, the demonstration of our room-temperature solution-processed and metal oxide-free flexible transparent bottom electrode will contribute to the emerging large-area flexible PVSC technologies.The exploration of low-temperature and solution-processed charge transporting and collecting layers can promote the development of low-cost and large-scale perovskite solar cells (PVSCs) through an all solution process. Here, we propose a room-temperature solution-processed and metal oxide-free nano-composite composed of a silver nano-network and graphene oxide (GO) flawless film for the transparent bottom electrode of a PVSC. Our experimental results show that the amount of GO flakes play a critical role in forming the flawless anti-corrosive barrier in the silver nano-network through a self

  12. Characterizing reactive oxygen generation and bacterial inactivation by a zerovalent iron-fullerene nano-composite device at neutral pH under UV-A illumination

    Energy Technology Data Exchange (ETDEWEB)

    Erdim, Esra [Center for the Environmental Implications of NanoTechnology, Duke University, Durham, NC 27708 (United States); Environmental Engineering Department, Marmara University, Istanbul 34469 (Turkey); Badireddy, Appala Raju [Center for the Environmental Implications of NanoTechnology, Duke University, Durham, NC 27708 (United States); Department of Civil and Environmental Engineering, Duke University, Durham, NC 27708 (United States); Wiesner, Mark R., E-mail: wiesner@duke.edu [Department of Civil and Environmental Engineering, Duke University, Durham, NC 27708 (United States); Department of Civil and Environmental Engineering, Duke University, Durham, NC 27708 (United States)

    2015-02-11

    Highlights: • We synthesized a novel ZVI/nC{sub 60} nano-composite device for multi-ROS generation. • O{sub 2}·{sup −} (UV-A independent) and {sup 1}O{sub 2} (UV-A dependent) are generated at neutral pH. • At low Fe concentration, ZVI/nC{sub 60} device is a better ROS generator than ZVI alone. • C{sub 60} mediates electron transfer from ZVI surface to dissolved O{sub 2} to produce O{sub 2}·{sup −}. • Bacteria are rapidly inactivated by O{sub 2}·{sup −} even at low ZVI/nC{sub 60} ratio. - Abstract: A nano-composite device composed of nano-scale zerovalent iron (ZVI) and C{sub 60} fullerene aggregates (ZVI/nC{sub 60}) was produced via a rapid nucleation method. The device was conceived to deliver reactive oxygen species (ROS) generated by photosensitization and/or electron transfer to targeted contaminants, including waterborne pathogens under neutral pH conditions. Certain variations of the nano-composite were fabricated differing in the amounts of (1) ZVI (0.1 mM and 2 mM) but not nC{sub 60} (2.5 mg-C/L), and (2) nC{sub 60} (0–25 mg-C/L) but not ZVI (0.1 mM). The generation of ROS by the ZVI/nC{sub 60} nano-composites and ZVI nanoparticles was quantified using organic probe compounds. 0.1 mM ZVI/2.5 mg-C/L C{sub 60} generated 3.74-fold higher O{sub 2}·{sup −} concentration and also resulted in an additional 2-log inactivation of Pseudomonas aeruginosa when compared to 0.1 mM ZVI (3-log inactivation). 2 mM ZVI/2.5 mg-C/L nC{sub 60} showed negligible improvement over 2 mM ZVI in terms of O{sub 2}·{sup −} generation or inactivation. Further, incremental amounts of nC{sub 60} in the range of 0–25 mg-C/L in 0.1 mM ZVI/nC{sub 60} led to increased O{sub 2}·{sup −} concentration, independent of UV-A. This study demonstrates that ZVI/nC{sub 60} device delivers (1) enhanced O{sub 2}·{sup −} with nC{sub 60} as a mediator for electron transfer, and (2) {sup 1}O{sub 2} (only under UV-A illumination) at neutral pH conditions.

  13. Graphene/Gold Nano composites-Based Thin Films as an Enhanced Sensing Platform for Voltammetric Detection of Cr(VI) Ions

    International Nuclear Information System (INIS)

    Santhosh, Ch.; Saranya, M.; Ramachandran, R.; Felix, S.; Velmurugan, V.; Grace, A.N.

    2014-01-01

    A highly sensitive and selective Cr(VI) sensor with graphene-based nano composites film as an enhanced sensing platform is reported. The detection of chromium species is a challenging task because of the different possible oxidation states in which the element can occur. The sensing film was developed by homogeneously distributing Au nanoparticles (AuNPs) onto the two-dimensional (2D) graphene nano sheet matrix by electrochemical method. Such nano structured composite film platforms combine the advantages of AuNPs and graph ene nano sheets because of the synergistic effect between them. This effect greatly facilitates the electron-transfer processes and the sensing behavior for Cr(VI) detection, leading to a remarkably improved sensitivity and selectivity. The interference from other heavy metal ions is studied in detail. Such sensing elements are very promising for practical environmental monitoring applications.

  14. Production of Al2O3–SiC nano-composites by spark plasma sintering

    International Nuclear Information System (INIS)

    Mansour Razavi; Ali Reza Farajipour; Mohammad Zakeri; Mohammad Reza Rahimipour; Ali Reza Firouzbakht

    2017-01-01

    In this paper, Al2O3–SiC composites were produced by SPS at temperatures of 1600°C for 10min under vacuum atmosphere. For preparing samples, Al2O3 with the second phase including of micro and nano-sized SiC powder were milled for 5h. The milled powders were sintered in a SPS machine. After sintering process, phase studies, densification and mechanical properties of Al2O3–SiC composites were examined. Results showed that the specimens containing micro-sized SiC have an important effect on bulk density, hardness and strength. The highest relative density, hardness and strength were 99.7%, 324.6 HV and 2329MPa, respectively, in Al2O3–20wt% SiCmicro composite. Due to short time sintering, the growth was limited and grains still remained in nano-meter scale. [es

  15. Investigations of Relaxation Dynamics and Observation of Nearly Constant Loss Phenomena in PEO_2_0-LiCF_3SO_3-ZrO_2 Based Polymer Nano-Composite Electrolyte

    International Nuclear Information System (INIS)

    Dam, Tapabrata; Tripathy, Satya N.; Paluch, Marian; Jena, Sidhartha S.; Pradhan, Dillip K.

    2016-01-01

    Highlights: • Ion conduction mechanism is studied using broad band dielectric spectroscopy. • Existence and cause of Nearly Constant Loss is explored. • The crossover between UDR to NCL phenomena is investigated. • Effect of filler concentration on ion transport using scaling approach is discussed. - Abstract: The conduction mechanism of polymer nano-composite electrolytes are studied using broadband dielectric spectroscopy over a wide range of frequency and temperature. The polymer nano-composites consisting of polyethylene oxide as polymer host, lithium trifluoromethanesulfonate as salt, and nano-crystalline zirconia as filler are prepared using solution casting method. Formation of polymer salt complex and nano-composites are confirmed from x-ray diffraction studies. The electrical conductivity and relaxation phenomena of the polymer salt complex as well as the composites are studied using broadband dielectric spectroscopy. At room temperature, the dc conductivity of the polymer nano-composites are found higher by two orders of magnitude than that of corresponding polymer salt complex. Temperature dependence of dc conductivity is following Vogel-Tamman-Fulcher trend, suggesting strong coupling between ionic conductivity and segmental relaxation in polymer electrolytes. Relaxation phenomena are studied with dielectric and modulus formalism. Frequency dependent ac conductivity show universal dielectric response and nearly constant loss features at high and low temperature regions respectively. The origin of universal dielectric response and nearly constant loss are analysed and discussed using different approaches. Kramer - Krönig approach suggests the origin of nearly constant loss is due to caged ion dynamics feature.

  16. Synthesis and properties of Ag/ZnO/g-C3N4 ternary micro/nano composites by microwave-assisted method

    Science.gov (United States)

    Zhang, Zijie; Li, Xuexue; Chen, Haitao; Shao, Gang; Zhang, Rui; Lu, Hongxia

    2018-01-01

    Ag/ZnO/g-C3N4 ternary micro/nanocomposites, as novel visible-light-driven photocatalysts, were prepared by a simple and convenient microwave-assisted method. The resulting ternary structure micro/nano composites were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy, ultraviolet-visible diffuse reflectance spectroscopy and infrared radiation techniques to examine its phase structure, valence state, morphological, thermal and optical properties. Well crystallized Ag/ZnO/g-C3N4 ternary micro/nano composites were synthesized under microwave-radiation for 15 min with the output of 240 W. Further experiments indicated Ag(5.0mol%)/ZnO/g-C3N4 photocatalyst in degradation of methylene blue exhibited an outstanding photocatalytic activity and its reaction rate constant (k, 0.0084 min-1) is 7.5, 2.4 2.9 and 3.5 times higher than that of monolithic ZnO (k, 0.0011 min-1), ZnO/g-C3N4(k, 0.0035 min-1), Ag(5 mol%)/ZnO(k, 0.0029 min-1) and Ag(5mol%)/g-C3N4 (k, 0.0024 min-1) respectively. Finally, a possible photocatalytic mechanism of Ag/ZnO/g-C3N4 photocatalyst in degradation process was proposed. This work provides a feasible strategy to synthesize an efficient ZnO-based photocatalyst which combines structure and properties of different dimensional components and made this ternary system an exciting candidate for sunlight-driven photocatalytic water treatment.

  17. Strengthening analyses and mechanical assessment of Ti/Al{sub 2}O{sub 3} nano-composites produced by friction stir processing

    Energy Technology Data Exchange (ETDEWEB)

    Shafiei-Zarghani, Aziz, E-mail: ashafiei@ut.ac.ir [Center of Excellence for Surface Engineering and Corrosion Protection of Industries, School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Kashani-Bozorg, Seyed Farshid, E-mail: fkashani@ut.ac.ir [Center of Excellence for Surface Engineering and Corrosion Protection of Industries, School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Gerlich, Adrian P., E-mail: adrian.gerlich@uwaterloo.ca [Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo (Canada)

    2015-04-17

    The present work investigates strengthening mechanisms and mechanical assessment of Ti/Al{sub 2}O{sub 3} nano-composites produced by friction stir processing of commercially pure titanium using nano-sized Al{sub 2}O{sub 3} with different volume fractions and particle sizes. Microstructural analyses were conducted to characterize the grain size of matrix, size and dispersion of reinforcing particles. The mean grain size of the composites ranged from ~0.7 to 1.1 μm that is much lower than 28 μm of the as-received material. Reduction of grain size was found to be in agreement with Rios approach (based on energy dissipated during the motion of an interface through particle dispersion), and showed deviation from Zener pinning model. Scanning and transmission electron microscopies revealed a near uniform dispersion of Al{sub 2}O{sub 3} nano-particles, with only a small fraction of widely spaced clusters. The maximum compression yield strength of the fabricated nano-composite (Ti/3.9%vol of 20 nm-Al{sub 2}O{sub 3}) was found to be ~494 MPa that is ~1.5 times higher than that of the as-received material. Strengthening analyses based on grain refining (Hall–Petch approach), load transfer from matrix to reinforcements, Orowan looping, and enhanced dislocation density due to thermal mismatch effects were carried out considering Al{sub 2}O{sub 3} reinforcement with different volume fractions and sizes. However, Hall–Petch approach was found to be the dominant mechanism for the enhancement of yield strength.

  18. Preparation of Ag@mSiO{sub 2} and Pt@mSiO{sub 2}nano composites using trioctylmethyl ammonium hydrogen phthalate (TOMAHP) ionic liquid as reaction medium

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Sujoy, E-mail: sujoyb@barc.gov.in [Chemical Engineering Group, Bhabha Atomic Research Centre, Mumbai 400085 (India); Dasgupta, Kinshuk [Materials Group, Bhabha Atomic Research Centre, Mumbai 400085 (India); Bahadur, Jitendra [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Tewari, Raghavendra [Materials Group, Bhabha Atomic Research Centre, Mumbai 400085 (India); Mazumder, Subhasish [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2016-09-15

    A novel one step green chemistry approach utilizing trioctylmethyl ammonium hydrogen phthalate (TOMAHP), task specific ionic liquid has been attempted for synthesis of Ag and Pt nanoparticles supported on silica (Ag@mSiO{sub 2} and Pt@mSiO{sub 2}). Structure, size distribution and morphology of these nano-composite particles were evaluated using X-ray diffraction (XRD), transmission electron microscopy (TEM), small angle neutron scattering (SANS) as well as small angle X-ray scattering (SAXS) techniques. The XRD results show that Ag/Pt metal nanoparticles deposited on to SiO{sub 2} surface are face center cubic (fcc) in nature. The TEM and SAXS/SANS results show the morphology and size distributions of Ag and Pt nanoparticles loaded on to the surface of SiO{sub 2}. It has been found that Ag nanoparticles are well dispersed on to the SiO{sub 2} surface and are quite monodisperse in size, whereas Pt nanoparticles are quite polydisperse in size and forms aggregate or chain like structure on SiO{sub 2} surface containing primary nanoparticles of typical size range 3–7 nm. The stability of nanoparticles, which controls its dispersion on SiO{sub 2} substrate, has been discussed. - Graphical abstract: Mechanism for Ag@mSiO{sub 2} and Pt@mSiO{sub 2} nano composites in TOMAHP ionic liquid medium. - Highlights: • Novel methods for preparation of Pt@SiO{sub 2} and Ag@SiO{sub 2} nano composite in functionalized ionic liquid. • Pt@SiO{sub 2} and Ag@SiO{sub 2} nano composite are characterized using XRD, TEM as well as small angle x-ray scattering techniques. • The sizes of nano composite is <10 nm in size. • The method is simple one step, green chemical reduction method to prepare SiO{sub 2} support nano catalyst.

  19. Standard hardness conversion tables for metals relationship among brinell hardness, vickers hardness, rockwell hardness, superficial hardness, knoop hardness, and scleroscope hardness

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 Conversion Table 1 presents data in the Rockwell C hardness range on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, Knoop hardness, and Scleroscope hardness of non-austenitic steels including carbon, alloy, and tool steels in the as-forged, annealed, normalized, and quenched and tempered conditions provided that they are homogeneous. 1.2 Conversion Table 2 presents data in the Rockwell B hardness range on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, Knoop hardness, and Scleroscope hardness of non-austenitic steels including carbon, alloy, and tool steels in the as-forged, annealed, normalized, and quenched and tempered conditions provided that they are homogeneous. 1.3 Conversion Table 3 presents data on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, and Knoop hardness of nickel and high-nickel alloys (nickel content o...

  20. Hard coatings

    International Nuclear Information System (INIS)

    Dan, J.P.; Boving, H.J.; Hintermann, H.E.

    1993-01-01

    Hard, wear resistant and low friction coatings are presently produced on a world-wide basis, by different processes such as electrochemical or electroless methods, spray technologies, thermochemical, CVD and PVD. Some of the most advanced processes, especially those dedicated to thin film depositions, basically belong to CVD or PVD technologies, and will be looked at in more detail. The hard coatings mainly consist of oxides, nitrides, carbides, borides or carbon. Over the years, many processes have been developed which are variations and/or combinations of the basic CVD and PVD methods. The main difference between these two families of deposition techniques is that the CVD is an elevated temperature process (≥ 700 C), while the PVD on the contrary, is rather a low temperature process (≤ 500 C); this of course influences the choice of substrates and properties of the coating/substrate systems. Fundamental aspects of the vapor phase deposition techniques and some of their influences on coating properties will be discussed, as well as the very important interactions between deposit and substrate: diffusions, internal stress, etc. Advantages and limitations of CVD and PVD respectively will briefly be reviewed and examples of applications of the layers will be given. Parallel to the development and permanent updating of surface modification technologies, an effort was made to create novel characterisation methods. A close look will be given to the coating adherence control by means of the scratch test, at the coating hardness measurement by means of nanoindentation, at the coating wear resistance by means of a pin-on-disc tribometer, and at the surface quality evaluation by Atomic Force Microscopy (AFM). Finally, main important trends will be highlighted. (orig.)

  1. Production of Al2O3–SiC nano-composites by spark plasma sintering

    Directory of Open Access Journals (Sweden)

    Mansour Razavi

    2017-07-01

    Full Text Available In this paper, Al2O3–SiC composites were produced by SPS at temperatures of 1600 °C for 10 min under vacuum atmosphere. For preparing samples, Al2O3 with the second phase including of micro and nano-sized SiC powder were milled for 5 h. The milled powders were sintered in a SPS machine. After sintering process, phase studies, densification and mechanical properties of Al2O3–SiC composites were examined. Results showed that the specimens containing micro-sized SiC have an important effect on bulk density, hardness and strength. The highest relative density, hardness and strength were 99.7%, 324.6 HV and 2329 MPa, respectively, in Al2O3–20 wt% SiCmicro composite. Due to short time sintering, the growth was limited and grains still remained in nano-meter scale.

  2. Production of Al2O3–SiC nano-composites by spark plasma sintering; Producción de nano-composites – SiC–Al2O3 por spark plasma sinterizado

    Energy Technology Data Exchange (ETDEWEB)

    Mansour Razavi; Ali Reza Farajipour; Mohammad Zakeri; Mohammad Reza Rahimipour; Ali Reza Firouzbakht

    2017-11-01

    In this paper, Al2O3–SiC composites were produced by SPS at temperatures of 1600°C for 10min under vacuum atmosphere. For preparing samples, Al2O3 with the second phase including of micro and nano-sized SiC powder were milled for 5h. The milled powders were sintered in a SPS machine. After sintering process, phase studies, densification and mechanical properties of Al2O3–SiC composites were examined. Results showed that the specimens containing micro-sized SiC have an important effect on bulk density, hardness and strength. The highest relative density, hardness and strength were 99.7%, 324.6 HV and 2329MPa, respectively, in Al2O3–20wt% SiCmicro composite. Due to short time sintering, the growth was limited and grains still remained in nano-meter scale. [Spanish] En este trabajo se muestran compuestos de Al2O3-SiC producidos por SPS, en vacío, a 1.600 °C durante 10 min. Para la preparación de muestras, se molieron polvos de Al2O3 durante 5 h con la segunda fase de micro-y-nano polvo de SiC. Posteriormente, estos polvos molidos se sinterizaron mediante SPS. Después del proceso de sinterización, se realizaron estudios de fase, densificación y propiedades mecánicas de los compuestos de Al2O3-SiC obtenidos. Los resultados mostraron que micro-SiC en las muestras tiene un efecto importante en su densidad aparente, dureza y resistencia. La mayor densidad relativa, dureza y resistencia fueron respectivamente del 99,7%, 324,6 HV y 2.329 MPa para Al2O3 con un 20% en peso micro-SiC. Debido al corto tiempo de sinterización, el crecimiento los granos fue limitado y se mantuvieron en escala nanométrica.

  3. Flow-induced crystallization of a nano composite of poly(butylene adipate-co-terephthalate)/montmorillonite; Cinetica de cristalizacao induzida por fluxo de nanocomposito de poli(butileno adipato-co-tereftalato)/montmorilonita

    Energy Technology Data Exchange (ETDEWEB)

    Bonel, Alan B [Universidade Federal de Sao Carlos. UFSCar, Departamento de Engenharia de Materiais DEMa, SP (Brazil); Rego, Bruna T; Beatrice, Cesar A.G.; Marini, Juliano; Bretas, Rosario E.S., E-mail: bretas@ufscar.br [Universidade Federal de Sao Carlos. UFSCar, Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais, SP (Brazil)

    2011-07-01

    Poly(butylene adipate-co-terephthalate) (PBAT) with 5wt% of an organically modified montmorillonite with polar surfactant was prepared by melt blending in a co-rotational twin-screw extruder at 160 degree C. 100rpm and 1 kg/h. Both pure polymer and nano composite were characterized by wide measurements. The study of the flow-induced crystallization was also done by rheological measurements, monitoring the viscosity as a function of time. The nano clay's lamellas were intercalated in the polymer m loss moduli of the nano composite, at low frequencies, showed that the particles of the nano clay were well dispersed and distributed thru the PBAT matrix. Finally, the presence of the nano clay's particles reduced the induction tim crystals growth, due to the strong interactions with the PBAT chains. (author)

  4. Combinatorial study of low-refractive Mg-F-Si-O nano-composites deposited by magnetron co-sputtering from compound targets

    Science.gov (United States)

    Mertin, Stefan; Länzlinger, Tony; Sandu, Cosmin S.; Scartezzini, Jean-Louis; Muralt, Paul

    2018-03-01

    Deposition of nano-composite Mg-F-Si-O films on optical grade silica glass was studied employing RF magnetron co-sputtering from magnesium fluoride (MgF2) and fused silica (SiO2) targets. The aim was to obtain a stable and reliable sputtering process for optical coatings exhibiting a refractive index lower than the one of quartz glass (1.46 at 550 nm) without adding gaseous fluorine to the deposition process. The two magnetrons were installed in a confocal way at 45° off-axis with respect to a static substrate, thus creating a lateral gradient in the thin-film composition. The deposited Mg-F-Si-O coatings were structurally analysed by electron dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The obtained films consist of MgF2 nanocrystals embedded in a SiO2-rich amorphous matrix. Spectroscopic ellipsometry and spectrophotometry measurements showed that they are highly transparent exhibiting a very-low extinction coefficient k and a refractive index n in the desired range between the one of MgF2 (1.38) and SiO2 (1.46). Films with n = 1.424 and 1.435 at 550 nm were accomplished with absorption below the detection threshold.

  5. The antifungal effects and mechanical properties of silver bromide/cationic polymer nano-composite-modified Poly-methyl methacrylate-based dental resin.

    Science.gov (United States)

    Zhang, Yu; Chen, Yin-Yan; Huang, Li; Chai, Zhi-Guo; Shen, Li-Juan; Xiao, Yu-Hong

    2017-05-08

    Poly-methyl methacrylate (PMMA)-based dental resins with strong and long-lasting antifungal properties are critical for the prevention of denture stomatitis. This study evaluated the antifungal effects on Candida albicans ATCC90028, the cytotoxicity toward human dental pulp cells (HDPCs), and the mechanical properties of a silver bromide/cationic polymer nano-composite (AgBr/NPVP)-modified PMMA-based dental resin. AgBr/NPVP was added to the PMMA resin at 0.1, 0.2, and 0.3 wt%, and PMMA resin without AgBr/NPVP served as the control. Fungal growth was inhibited on the AgBr/NPVP-modified PMMA resin compared to the control (P  0.05) between the experimental and control groups. These data indicate that the incorporation of AgBr/NPVP conferred strong and long-lasting antifungal effects against Candida albicans to the PMMA resin, and it has low toxicity toward HDPCs, and its mechanical properties were not significantly affected.

  6. Improved dehydriding property of polyvinylpyrrolidone coated Mg-Ni hydrogen storage nano-composite prepared by hydriding combustion synthesis and wet mechanical milling

    Directory of Open Access Journals (Sweden)

    Linglong Yao

    2018-02-01

    Full Text Available In this work, polyvinylpyrrolidone (PVP coated Mg95Ni5 nano-composites were prepared by hydriding combustion synthesis (HCS plus wet mechanical milling (WM with tetrahydrofuran (THF and donated as WM-x wt% PVP (x = 1, 3, 5 and 7 respectively. The phase compositions, microstructures and dehydriding property, as well as the co-effect of PVP and THF were investigated in detail. XRD results showed that the average crystal size of MgH2 in the milled Mg95Ni5 decreased from 23 nm without PVP to 18 nm with 1 wt% PVP. The peak temperature of dehydrogenation of MgH2 in the milled Mg95Ni5 decreased from 293.0 °C without THF to 250.4 °C with THF. The apparent activation energy for decomposition of MgH2 in WM-7 wt% PVP was estimated to be 66.94 kJ/mol, which is 37.70 kJ/mol lower than that of milled Mg95Ni5 without THF and PVP. PVP and THF can facilitate the refinement of particle size during mechanical milling process. Attributed to small particle sizes and synergistic effect of PVP and THF, the composites exhibit markedly improved dehydriding properties. Keywords: Mg-Ni-PVP, Composite, Mg-based alloy, Wet mechanical milling, Dehydriding temperature

  7. In vitro secretion of TNF-{alpha} from bone marrow mononuclear cells incubated on amino group modified TiO{sub 2} nano-composite under ultrasound irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Furuzono, T., E-mail: furuzono@ri.ncvc.go.jp [Department of Bioengineering, Advanced Medical Engineering Center, National Cardiovascular Center Research Institute, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565 (Japan); Masuda, M. [Department of Bioengineering, Advanced Medical Engineering Center, National Cardiovascular Center Research Institute, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565 (Japan); Nitta, N.; Kaya, A.; Yamane, T. [Institute for Human Science and Biomedical Engineering, National Institute of Advanced Industrial Science and Technology, 1-2-1 Namiki, Tsukuba, Ibaraki, 305-8564 (Japan); Okada, M. [Department of Bioengineering, Advanced Medical Engineering Center, National Cardiovascular Center Research Institute, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565 (Japan)

    2010-10-15

    It is recently known that titanium dioxide (TiO{sub 2}) can be excited by ultrasound and release of OH radicals on the surface. In this study, secretion of an indirect angiogenic factor, tumor necrosis factor-{alpha} (TNF-{alpha}), from bone marrow mononuclear cells (BM-MNC) incubated on amino group modified TiO{sub 2} nano-particles covalently coated on polyester fabric (TiO{sub 2}/PET) under ultrasonic irradiation was examined in vitro. The cell viability and TNF-{alpha} secretion were measured under ultrasound irradiation condition with 255 mW/cm{sup 2} of intensity, which is below the highest output (1 W/cm{sup 2}) specified in the safety standard for a medical ultrasonic diagnostic apparatus. The living cell number on the TiO{sub 2}/PET and original PET with/without continuous ultrasound irradiation was unchanged statistically by ANOVA test. TNF-{alpha} secretion level from BM-MNC remarkably increased on the TiO{sub 2}/PET under ultrasonic irradiation without cell damage. It was, therefore, thought that the high level of TNF-{alpha} secretion on the TiO{sub 2} nano-composite by ultrasound irradiation was due to oxidative stress induced from OH radicals on TiO{sub 2}.

  8. Chitosan mediated synthesis of core/double shell ternary polyaniline/Chitosan/cobalt oxide nano composite-as high energy storage electrode material in supercapacitors

    International Nuclear Information System (INIS)

    Vellakkat, Mini; Hundekkal, Devendrappa

    2016-01-01

    Nanostructured ternary composite of polyaniline (PANI), Co 3 O 4 nanoparticles, and Chitosan (CS) has been prepared by an in situ chemical oxidation method, and the nanocomposites (CPAESCO) were used as supercapacitor electrodes. The Co 3 O 4 nanoparticles are uniformly coated with CS and PANI layers in it. Different techniques (Fourier transform infrared spectrophotometry, x-ray diffraction, thermal gravimetric analysis, UV−visible spectroscopy, scanning electron microscopy, transmission electron microscopy and electro chemical analysis-cyclic voltammetry, galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy) were used to analyse the optical, structural, thermal, chemical and supercapacitive aspects of the nanocomposites. Core/double shell ternary composite electrode exhibits significantly increased specific capacitance than PANI/Co 3 O 4 or PANI/CS binary composites in supercapacitors. The ternary nanocomposite with 40% nanoparticle exhibits a highest specific capacitance reaching 687 F g −1 , Energy density of (95.42 Wh kg −1 at 1 A g −1 ) and power density of (1549 W kg −1 at 3 A g −1 ) and outstanding cycling performance, with, 91% capacitance retained over 5000 cycles. It is found that this unique bio compatible nano composite with synergy is a new multifunctional material which will be useful in the design of supercapacitor electrodes and other energy conversion devices too. (paper)

  9. Highly efficient inverted organic light emitting diodes by inserting a zinc oxide/polyethyleneimine (ZnO:PEI) nano-composite interfacial layer

    Science.gov (United States)

    Kaçar, Rifat; Pıravadılı Mucur, Selin; Yıldız, Fikret; Dabak, Salih; Tekin, Emine

    2017-06-01

    The electrode/organic interface is one of the key factors in attaining superior device performance in organic electronics, and inserting a tailor-made layer can dramatically modify its properties. The use of nano-composite (NC) materials leads to many advantages by combining materials with the objective of obtaining a desirable combination of properties. In this context, zinc oxide/polyethyleneimine (ZnO:PEI) NC film was incorporated as an interfacial layer into inverted bottom-emission organic light emitting diodes (IBOLEDs) and fully optimized. For orange-red emissive MEH-PPV based IBOLEDs, a high power efficiency of 6.1 lm W-1 at a luminance of 1000 cd m-2 has been achieved. Notably, the external quantum efficiency (EQE) increased from 0.1 to 4.8% and the current efficiency (CE) increased from 0.2 to 8.7 cd A-1 with rise in luminance (L) from 1000 to above 10 000 cd m-2 levels when compared to that of pristine ZnO-based devices. An identical device architecture containing a ZnO:PEI NC layer has also been used to successfully fabricate green and blue emissive IBOLEDs. The significant enhancement in the inverted device performance, in terms of luminance and efficiency, is attributed to a good energy-level alignment between the cathode/organic interface which leads to effective carrier balance, resulting in efficient radiative-recombination.

  10. Investigation of dosimetric characteristics of a core-shell quantum dots nano composite (CdTe/CdS/PMMA): fabrication of a new gamma sensor

    Science.gov (United States)

    Feizi, Shahzad; Zare, Hakimeh; Hoseinpour, Masoumeh

    2018-06-01

    CdTe/CdS-PMMA nanocomposite was prepared using dispersion of CdTe/CdS core-shell quantum dots (QDs) in poly methyl methacrylate (PMMA) polymer matrix. High-quality CdTe/CdS core/shell quantum dots were synthesized in aqueous solution and were transferred from water to chloroform using ligand-exchange process in the presence of 1-dodecanethiol (1-DDT). Transmission electron microscopy analysis reveals that the obtained nano-particles are highly crystalline nature with mean diameter of 3.6 nm. To prepare an ohmic contact detector, a conductive cell with two silver coated walls was designed and fabricated for exploring gamma detecting properties of the nano composite. New detector was assessed for the linearity of doserate response, angular dependence, sensitivity and repeatability. The results show that the dose rate response of the prepared sensor is linear in the dose rate range of 50-145 mGy/min. So this nanocomposite can be utilized as a potential gamma sensor in the medical radiation device design.

  11. Hydrogen storage and hydrolysis properties of core-shell structured Mg-MFx (M=V, Ni, La and Ce) nano-composites prepared by arc plasma method

    Science.gov (United States)

    Mao, Jianfeng; Zou, Jianxin; Lu, Chong; Zeng, Xiaoqin; Ding, Wenjiang

    2017-10-01

    In this work, core-shell structured Mg-MFx (M = V, Ni, La and Ce) nano-composites are prepared by using arc plasma method. The particle size distribution, phase components, microstructures, hydrogen sorption properties of these composites and hydrolysis properties of their corresponding hydrogenated powders are carefully investigated. It is shown that the addition of MFx through arc plasma method can improve both the hydrogen absorption kinetics of Mg and the hydrolysis properties of corresponding hydrogenated powders. Among them, the Mg-NiF2 composite shows the best hydrogen absorption properties at relatively low temperatures, which can absorb 3.26 wt% of H2 at 373 K in 2 h. Such rapid hydrogen absorption rate is mainly due to the formation of Mg2Ni and MgF2 on Mg particles during arc evaporation and condensation. In contrast, measurements also show that the hydrogenated Mg-VF3 composite has the lowest peak desorption temperature and the fastest hydrolysis rate among all the hydrogenated Mg-MFx composites. The less agglomeration tendency of Mg particles and VO2 covered on MgH2 particles account for the reduced hydrogen desorption temperature and enhanced hydrolysis rate.

  12. In vitro secretion of TNF-α from bone marrow mononuclear cells incubated on amino group modified TiO2 nano-composite under ultrasound irradiation

    International Nuclear Information System (INIS)

    Furuzono, T.; Masuda, M.; Nitta, N.; Kaya, A.; Yamane, T.; Okada, M.

    2010-01-01

    It is recently known that titanium dioxide (TiO 2 ) can be excited by ultrasound and release of OH radicals on the surface. In this study, secretion of an indirect angiogenic factor, tumor necrosis factor-α (TNF-α), from bone marrow mononuclear cells (BM-MNC) incubated on amino group modified TiO 2 nano-particles covalently coated on polyester fabric (TiO 2 /PET) under ultrasonic irradiation was examined in vitro. The cell viability and TNF-α secretion were measured under ultrasound irradiation condition with 255 mW/cm 2 of intensity, which is below the highest output (1 W/cm 2 ) specified in the safety standard for a medical ultrasonic diagnostic apparatus. The living cell number on the TiO 2 /PET and original PET with/without continuous ultrasound irradiation was unchanged statistically by ANOVA test. TNF-α secretion level from BM-MNC remarkably increased on the TiO 2 /PET under ultrasonic irradiation without cell damage. It was, therefore, thought that the high level of TNF-α secretion on the TiO 2 nano-composite by ultrasound irradiation was due to oxidative stress induced from OH radicals on TiO 2 .

  13. Fabrication of Al/Graphite/Al2O3 Surface Hybrid Nano Composite by Friction Stir Processing and Investigating The Wear and Microstructural Properties of The Composite

    Directory of Open Access Journals (Sweden)

    A. Mostafapour

    2012-10-01

    Full Text Available Friction stir processing was applied for fabricating an aluminum alloy based hybrid nano composite reinforced with nano sized Al2O3 and micro sized graphite particles. A mixture of Al2O3 and graphite particles was packed into a groove with 1 mm width and 4.5 mm depth, which had been cut in 5083 aluminum plate of 10 mm thick. Packed groove was subjected to friction stir processing in order to implement powder mixture into the aluminum alloy matrix. Microstructural properties were investigated by means of optical microscopy and scanning electron microscopy (SEM. It was found that reinforcement particle mixture was distributed uniformly in nugget zone. Wear resistance of composite was measured by dry sliding wear test. As a result, hybrid composite revealed significant reduction in wear rate in comparison with Al/AL2O3 composite produced by friction stir processing. Worn surface of the wear test samples were examined by SEM in order to determine wear mechanism.

  14. Characterization of dispersion of a nano composites PP/TiO{sub 2} non modified; Caracterizacao da dispersao dos nanocompositos de PP/TiO{sub 2} nao modificados

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Igor L.; Tavares, Maria I.B.; Silva, Vanessa A. da; Legramanti, Cintia, E-mail: igorl@ima.ufrj.br [Universidade Federal do Rio de Janeiro - UFRJ, Instituto de Macromoleculas - IMA (Brazil); Luetkmeyer, Leandro [Universidades Federais do Mato Grosso - UFMT, Escritorio de Inovacao Tecnologica - EIT (Brazil)

    2011-07-01

    Polymeric nano composites are composite materials where an inorganic particle, which has a dimension in the nanometer range, is dispersed in a polymer matrix. Nano composites, using polypropylene (PP) as matrix polymer and titanium dioxide (TiO{sub 2}) as filler, have great versatility in marketing applications, this factor is inherent in the PP and the inherent ability photo degraded TiO{sub 2} particles. This combination can lead to a widely used material and a degradation time after discharge reduced, there by becoming, a residue of low environmental impact. This study aimed to evaluate the dispersion and particle distribution of TiO{sub 2}, non modified, in PP matrix, using the process of preparation by melt extrusion pathway and characterization of the materials obtained: on the molecular dynamics, using low field NMR solid state, measures the relaxation time spin-network (T{sub 1}H); morphology using XRD technique, and thermal analysis technique with the TGA of pure PP and nano composites PP/TiO{sub 2}. (author)

  15. Preparation and characterization of green-nano-composite material based on polyaniline, multiwalled carbon nano tubes and carboxymethyl cellulose: For electrochemical sensor applications.

    Science.gov (United States)

    Gautam, Vineeta; Singh, Karan Pratap; Yadav, Vijay Laxmi

    2018-06-01

    In this paper, we are presenting the preparation and characterization of "polyaniline/multiwalled carbon nanotubes/carboxymethyl cellulose" based novel composite material. It's morphological, thermal, structural, and electrochemical properties were investigated by using different instrumental techniques. During the in-situ chemical polymerization of aniline in the aqueous suspension of CMC and MWCNTs, the particle size change in two different ways "top to bottom" (low molecular weight oligomers grows in size) and "bottom to top" (long fibers of CMC fragmented in the reaction mixture). The combination of these two processes facilitated the fabrication of an integrated green-nano-composite material. In addition, a little amount of conductive nanofillers (MWCNTs) boosts the electrical and electrocatalytic properties of the material. Electron-rich centers of benzenoid rings exhibited π-π stacking with sp 2 carbon of MWCNTs. CMC dominantly impact on the properties of PANI, negatively charged carboxylate group of CMC ionically bonded with protonated amine/imine. FTIR and Raman analysis confirmed that the material has dominated quinoid units and effective charge transfer. Hydroxyl and carboxyl groups and bonded water molecules of CMC results in a network of hydrogen bonds (which induced directional property). PANI/MWCNTs/CMC have nanobead-like structures (TEM analysis), large surface area, large pore volume, small pore diameter (BET and BJH studies) and good dispersion ability in the aqueous phase. Nanostructures of aligned PANI exhibited excellent electrochemical properties have attracted increasing attention. Modified carbon paste electrode was used for electrocatalytic detection of ascorbic acid (as a model analyte). The sensor exhibited a linear range 0.05 mM-5 mM, sensitivity 100.63 μA mM -1  cm -2 , and limit of detection 0.01 mM. PANI/MWCNTs/CMC is suitable nanocomposite material for apply electroactive/conducting ink and membrane (which could be

  16. Nano-composite stainless steel

    Science.gov (United States)

    Dehoff, Ryan R.; Blue, Craig A.; Peter, William H.; Chen, Wei; Aprigliano, Louis F.

    2015-07-14

    A composite stainless steel composition is composed essentially of, in terms of wt. % ranges: 25 to 28 Cr; 11 to 13 Ni; 7 to 8 W; 3.5 to 4 Mo; 3 to 3.5 B; 2 to 2.5 Mn; 1 to 1.5 Si; 0.3 to 1.7 C; up to 2 O; balance Fe. The composition has an austenitic matrix phase and a particulate, crystalline dispersed phase.

  17. Dual Delivery of BMP-2 and bFGF from a New Nano-Composite Scaffold, Loaded with Vascular Stents for Large-Size Mandibular Defect Regeneration

    Directory of Open Access Journals (Sweden)

    Hang Zhao

    2013-06-01

    Full Text Available The aim of this study was to investigate the feasibility and advantages of the dual delivery of bone morphogenetic protein-2 (BMP-2 and basic fibroblast growth factor (bFGF from nano-composite scaffolds (PLGA/PCL/nHA loaded with vascular stents (PLCL/Col/nHA for large bone defect regeneration in rabbit mandibles. Thirty-six large bone defects were repaired in rabbits using engineering bone composed of allogeneic bone marrow mesenchymal stem cells (BMSCs, bFGF, BMP-2 and scaffolds composed of PLGA/PCL/nHA loaded with PLCL/Col/nHA. The experiments were divided into six groups: BMSCs/bFGF/BMP-2/scaffold, BMSCs/BMP-2/scaffold, BMSCs/bFGF/scaffold, BMSCs/scaffold, scaffold alone and no treatment. Sodium alginate hydrogel was used as the carrier for BMP-2 and bFGF and its features, including gelling, degradation and controlled release properties, was detected by the determination of gelation and degradation time coupled with a controlled release study of bovine serum albumin (BSA. AlamarBlue assay and alkaline phosphatase (ALP activity were used to evaluate the proliferation and osteogenic differentiation of BMSCs in different groups. X-ray and histological examinations of the samples were performed after 4 and 12 weeks post-implantation to clarify new bone formation in the mandible defects. The results verified that the use of sodium alginate hydrogel as a controlled release carrier has good sustained release ability, and the combined application of bFGF and BMP-2 could significantly promote the proliferation and osteogenic differentiation of BMSCs (p < 0.05 or p < 0.01. In addition, X-ray and histological examinations of the samples exhibited that the dual release group had significantly higher bone formation than the other groups. The above results indicate that the delivery of both growth factors could enhance new bone formation and vascularization compared with delivery of BMP-2 or bFGF alone, and may supply a promising way of repairing large

  18. Dual mode emission and harmonic generation in ZnO-CaO-Al{sub 2}O{sub 3}: Er{sup 3+} nano-composite

    Energy Technology Data Exchange (ETDEWEB)

    Verma, R.K. [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005 (India); Kumar, K. [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005 (India); Nano-technology Application Centre, University of Allahabad, Allahabad (India); Rai, S.B., E-mail: sbrai49@yahoo.co.i [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005 (India)

    2011-05-15

    Er{sup 3+} doped ZnO-CaO-Al{sub 2}O{sub 3} nano-composite phosphor has been synthesized through combustion method and its emission and harmonic generation properties have been studied. The X-ray diffraction and thermal analysis techniques have been used to prove the dual phase (ZnO and CaO-Al{sub 2}O{sub 3}) nature of the phosphor. The phosphor has shown up-conversion emission on near-infra-red (976 nm) excitation and down-conversion emission on 355 nm excitation in presence of Er{sup 3+} and thus behaves as a dual mode phosphor. On excitation with 976 nm diode laser, material shows color tunability (calcination of composite material at different temperatures). Formation of ZnO nanocrystals on heat treatment of as-synthesized sample has shown its characteristic emission at 388 nm and also the energy transfer from ZnO to Er{sup 3+} ions. The low temperature emission measurements have been carried out and the results have been discussed. Phosphor has shown strong second harmonic generation (SHG) at 532 nm on 1064 nm and at 266 nm on 532 nm excitation. - Research highlights: {yields} We have synthesized Er{sup 3+} doped composite material by combustion method. The two phases of composites are ZnO and CaO-Al{sub 2}O{sub 3}. {yields} The phosphor has shown up-conversion emission on near-infra-red (976 nm) excitation and down-conversion emission on 355 nm excitation in presence of Er{sup 3+} and thus behaves as a dual mode phosphor. This material also shows colour tenability on excitation of 976 nm diode laser at different temperature calcinations (i.e., As-synthesized to calcinated at 1473 K). {yields} Low temperature effects on Er{sup 3+} as well as ZnO emission have been carried out. We observed that at low temperature the efficiency of Er{sup 3+} increases while in the case of ZnO its intensity increases and also 12 nm shifting observed. {yields} Composite material has shown strong second harmonic generation (SHG) at 532 nm on 1064 nm and at 266 nm on 532 nm

  19. Preparation and characterization of functionalized cellulose nano crystals with methyl adipoyl chloride used to prepare chitosan grafting nano composite; Preparacao e caracterizacao de nanocristais de celulose funcionalizados com CMA utilizados na preparacao de nanocomposito de quitosana reticulado

    Energy Technology Data Exchange (ETDEWEB)

    Mesquita, Joao Paulo de; Teixeira, Ivo F; Donnici, Claudio L; Pereira, Fabiano V [Universidade Federal de Minas Gerais - UFMG, Belo Horizonte, MG (Brazil)

    2011-07-01

    Cellulose nano crystals (CNCs) were prepared from eucalyptus pulp and functionalized with methyl adipoyl chloride. The nano materials were characterized by different techniques including FTIR, 1H NMR and XRD which showed that the functionalization occurs only on the surface of the nano structures without change in crystalline structure of the nanoparticles. The new-functionalized CNCs were used as reinforcement in the preparation of a nano composite with chitosan, through the formation of a covalent bond between the nano filler and matrix. Preliminary results of mechanical tests indicate an improvement in tensile strength and increase in deformation of chitosan. (author)

  20. Synthesis and characterization of poly-o-anisidine Sn(IV tungstate: A new and novel ‘organic–inorganic’ nano-composite material and its electro-analytical applications as Hg(II ion-selective membrane electrode

    Directory of Open Access Journals (Sweden)

    Asif A. Khan

    2012-07-01

    Full Text Available An organic–inorganic nano-composite poly-o-anisidine Sn(IV tungstate was chemically synthesized by sol–gel mixing of the incorporation of organic polymer o-anisidine into the matrices of inorganic ppt of Sn(IV tungstate in different mixing volume ratios. This composite material has been characterized using various analytical techniques like XRD (X-ray diffraction, FTIR (Fourier transform infrared, SEM (Scanning electron microscopy, TEM (Transmission electron microscopy and simultaneous TGA (Thermogravimetric analysis studies. On the basis of distribution studies, the material was found to be highly selective for Hg(II. Using this nano-composite cation exchanger as electro-active material, a new heterogeneous precipitate based on ion-sensitive membrane electrode was developed for the determination of Hg(II ions in solutions. The membrane electrode was mechanically stable, with a quick response time, and can be operated within a wide pH range. The electrode was also found to be satisfactory in electrometric titrations.

  1. The study of structural properties of carbon nanotubes decorated with NiFe₂O₄ nanoparticles and application of nano-composite thin film as H₂S gas sensor.

    Science.gov (United States)

    Hajihashemi, R; Rashidi, Ali M; Alaie, M; Mohammadzadeh, R; Izadi, N

    2014-11-01

    Nano-composite of multiwall carbon nanotube, decorated with NiFe2O4 nanoparticles (NiFe2O4-MWCNT), was synthesized using the sol-gel method. NiFe2O4-MWCNTs were characterized using different methods such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM) and vibrating sample magnetometer (VSM). The average size of the crystallites is 23.93 nm. The values of the saturation magnetization (MS), coercivity (HC) and retentivity (MR) of NiFe2O4-MWCNTs are obtained as 15 emu g(-1), 21Oe and 5 emu g(-1), respectively. In this research, NiFe2O4-MWCNT thin films were prepared with the spin-coating method. These thin films were used as the H2S gas sensor. The results suggest the possibility of the utilization of NiFe2O4-MWCNT nano-composite, as the H2S detector. The sensor shows appropriate response towards 100 ppm of H2S at 300°C. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Cobalt ferrite nano-composite coated on glass by Doctor Blade method for photo-catalytic degradation of an azo textile dye Reactive Red 4: XRD, FESEM and DRS investigations.

    Science.gov (United States)

    Habibi, Mohammad Hossein; Parhizkar, Janan

    2015-11-05

    Cobalt ferrite nano-composite was prepared by hydrothermal route using cobalt nitrate, iron nitrate and ethylene glycol as chelating agent. The nano-composite was coated on glass by Doctor Blade method and annealed at 300 °C. The structural, optical, and photocatalytic properties have been studied by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV-visible spectroscopy (UV-Vis DRS). Powder XRD analysis confirmed formation of CoFe2O4 spinel phase. The estimated particle size from FESEM data was 50 nm. The calculated energy band gaps, obtained by Tauc relation from UV-Vis absorption spectra was 1.3 eV. Photocatalytic degradation of Reactive Red 4 as an azo textile was investigated in aqueous solution under irradiation showed 68.0% degradation of the dye within 100 min. The experimental enhanced activity compare to pure Fe2O3 can be ascribed to the formation of composite, which was mainly attributable to the transfer of electron and hole to the surface of composite and hinder the electron hole recombination. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Effect of annealing temperature on optical properties of binary zinc tin oxide nano-composite prepared by sol-gel route using simple precursors: structural and optical studies by DRS, FT-IR, XRD, FESEM investigations.

    Science.gov (United States)

    Habibi, Mohammad Hossein; Mardani, Maryam

    2015-02-25

    Binary zinc tin oxide nano-composite was synthesized by a facile sol-gel method using simple precursors from the solutions consisting of zinc acetate, tin(IV) chloride and ethanol. Effect of annealing temperature on optical and structural properties was investigated using X-ray diffraction (XRD), diffuse reflectance spectra (DRS), field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). XRD results revealed the existence of the ZnO and SnO2 phases. FESEM results showed that binary zinc tin oxide nano-composites ranges from 56 to 60 nm in diameter at 400°C and 500°C annealing temperatures respectively. The optical band gap was increased from 2.72 eV to 3.11 eV with the increasing of the annealing temperature. FTIR results confirmed the presence of zinc oxide and tin oxide and the broad absorption peaks at 3426 and 1602 cm(-1) can be ascribed to the vibration of absorptive water, and the absorption peaks at 546, 1038 and 1410 cm(-1) are due to the vibration of Zn-O or Sn-O groups in binary zinc tin oxide. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Extremely fine structured cathode for solid oxide fuel cells using Sr-doped LaMnO3 and Y2O3-stabilized ZrO2 nano-composite powder synthesized by spray pyrolysis

    Science.gov (United States)

    Shimada, Hiroyuki; Yamaguchi, Toshiaki; Sumi, Hirofumi; Nomura, Katsuhiro; Yamaguchi, Yuki; Fujishiro, Yoshinobu

    2017-02-01

    A solid oxide fuel cell (SOFC) for high power density operation was developed with a microstructure-controlled cathode using a nano-composite powder of Sr-doped LaMnO3 (LSM) and Y2O3-stabilized ZrO2 (YSZ) synthesized by spray pyrolysis. The individual LSM-YSZ nano-composite particles, formed by crystalline and amorphous nano-size LSM and YSZ particles, showed spherical morphology with uniform particle size. The use of this powder for cathode material led to an extremely fine microstructure, in which all the LSM and YSZ grains (approximately 100-200 nm) were highly dispersed and formed their own network structures. This microstructure was due to the two phase electrode structure control using the powder, namely, nano-order level in each particle and micro-order level between particles. An anode-supported SOFC with the LSM-YSZ cathode using humidified H2 as fuel and ambient air as oxidant exhibited high power densities, such as 1.29 W cm-2 under a voltage of 0.75 V and a maximum power density of 2.65 W cm-2 at 800 °C. Also, the SOFC could be stably operated for 250 h with no degradation, even at a high temperature of 800 °C.

  5. Formulation and characterization of polyethylenes and organo-clays. Barrier properties of the obtained nano-composites; Formulation et caracterisation de polyethylenes charges avec des argiles. Proprietes barriere des nanocomposites obtenus

    Energy Technology Data Exchange (ETDEWEB)

    Wache, R

    2004-10-01

    The particularity of polymer layered silicate nano-composites is based on the exfoliation of the clay platelets in the polymer matrix. Therefore properties may be dramatically modified with very low clay loading. In this work polyethylene and organo-clay have been melt blended. Due to a lack of polarity, the polymer chains do not intercalate the clay stacking. However exfoliation is achieved using maleate polyethylene. We used this polymer as a compatibilizer to promote clay exfoliation in the polyethylene matrix. Partial exfoliation is obtained. Barrier properties of these materials have been characterized. Permeability is higher for the clay reinforced products than their matrix. To understand the poor permeability results a tortuosity model has been developed. The quality of the interface seems to be involved. Several organo-clays and compatibilizers have been tested to improve it. But for the concentrations of these products used polyethylene clay interactions always exist and lead to an increase of diffusion. (author)

  6. Comparative studies of microstructural, tribological and corrosion properties of Zn-TiO2 and Zn-TiO2-WO3 nano-composite coatings

    Directory of Open Access Journals (Sweden)

    A.A. Daniyan

    Full Text Available Nano sized composites of Zn-TiO2 and Zn-TiO2-WO3 were produced via electrocodeposition on plain carbon steel. The effect of input current on the microstructure, mechanical strengthening and corrosion properties were compared. The morphological features of the composite coatings were characterized by scanning electron microscope (SEM equipped with energy dispersive spectrometer (EDS; mechanical properties were carried out using a diamond base Dura Scan hardness tester and CERT UMT-2 multi-functional tribological tester. The corrosion properties were investigated by potentiodynamic studies in 3.5% NaCl. The result showed that the coatings exhibited good stability and the particle loading of WO3 greatly enhanced the microstructural properties, hardness behaviour and corrosion resistance of the coatings. Keywords: Zn-TiO2, Zn-TiO2-WO3, Electrocodeposition, Microstructure, Composite, Stability and coatings

  7. Comprehensive hard materials

    CERN Document Server

    2014-01-01

    Comprehensive Hard Materials deals with the production, uses and properties of the carbides, nitrides and borides of these metals and those of titanium, as well as tools of ceramics, the superhard boron nitrides and diamond and related compounds. Articles include the technologies of powder production (including their precursor materials), milling, granulation, cold and hot compaction, sintering, hot isostatic pressing, hot-pressing, injection moulding, as well as on the coating technologies for refractory metals, hard metals and hard materials. The characterization, testing, quality assurance and applications are also covered. Comprehensive Hard Materials provides meaningful insights on materials at the leading edge of technology. It aids continued research and development of these materials and as such it is a critical information resource to academics and industry professionals facing the technological challenges of the future. Hard materials operate at the leading edge of technology, and continued res...

  8. Induced spherococcoid hard wheat

    International Nuclear Information System (INIS)

    Yanev, Sh.

    1981-01-01

    A mutant has been obtained - a spheroccocoid line -through irradiation of hard wheat seed with fast neutrons. It is distinguished by semispherical glumes and smaller grain; the plants have low stem with erect leaves but with shorter spikes and with lesser number of spikelets than those of the initial cultivar. Good productive tillering and resistance to lodging contributed to 23.5% higher yield. The line was superior to the standard and the initial cultivars by 14.2% as regards protein content, and by up to 22.8% - as to flour gluten. It has been successfully used in hybridization producing high-yielding hard wheat lines resistant to lodging, with good technological and other indicators. The possibility stated is of obtaining a spherococcoid mutant in tetraploid (hard) wheat out of the D-genome as well as its being suited to hard wheat breeding to enhance protein content, resistance to lodging, etc. (author)

  9. Hard probes 2006 Asilomar

    CERN Multimedia

    2006-01-01

    "The second international conference on hard and electromagnetic probes of high-energy nuclear collisions was held June 9 to 16, 2006 at the Asilomar Conference grounds in Pacific Grove, California" (photo and 1/2 page)

  10. Hard coal; Steinkohle

    Energy Technology Data Exchange (ETDEWEB)

    Loo, Kai van de; Sitte, Andreas-Peter [Gesamtverband Steinkohle e.V., Herne (Germany)

    2013-04-01

    The year 2012 benefited from a growth of the consumption of hard coal at the national level as well as at the international level. Worldwide, the hard coal still is the number one energy source for power generation. This leads to an increasing demand for power plant coal. In this year, the conversion of hard coal into electricity also increases in this year. In contrast to this, the demand for coking coal as well as for coke of the steel industry is still declining depending on the market conditions. The enhanced utilization of coal for the domestic power generation is due to the reduction of the nuclear power from a relatively bad year for wind power as well as reduced import prices and low CO{sub 2} prices. Both justify a significant price advantage for coal in comparison to the utilisation of natural gas in power plants. This was mainly due to the price erosion of the inexpensive US coal which partly was replaced by the expansion of shale gas on the domestic market. As a result of this, the inexpensive US coal looked for an outlet for sales in Europe. The domestic hard coal has continued the process of adaptation and phase-out as scheduled. Two further hard coal mines were decommissioned in the year 2012. RAG Aktiengesellschaft (Herne, Federal Republic of Germany) running the hard coal mining in this country begins with the preparations for the activities after the time of mining.

  11. Soft and hard pomerons

    International Nuclear Information System (INIS)

    Maor, Uri; Tel Aviv Univ.

    1995-09-01

    The role of s-channel unitarity screening corrections, calculated in the eikonal approximation, is investigated for soft Pomeron exchange responsible for elastic and diffractive hadron scattering in the high energy limit. We examine the differences between our results and those obtained from the supercritical Pomeron-Regge model with no such corrections. It is shown that screening saturation is attained at different scales for different channels. We then proceed to discuss the new HERA data on hard (PQCD) Pomeron diffractive channels and discuss the relationship between the soft and hard Pomerons and the relevance of our analysis to this problem. (author). 18 refs, 9 figs, 1 tab

  12. Hard exclusive QCD processes

    Energy Technology Data Exchange (ETDEWEB)

    Kugler, W.

    2007-01-15

    Hard exclusive processes in high energy electron proton scattering offer the opportunity to get access to a new generation of parton distributions, the so-called generalized parton distributions (GPDs). This functions provide more detailed informations about the structure of the nucleon than the usual PDFs obtained from DIS. In this work we present a detailed analysis of exclusive processes, especially of hard exclusive meson production. We investigated the influence of exclusive produced mesons on the semi-inclusive production of mesons at fixed target experiments like HERMES. Further we give a detailed analysis of higher order corrections (NLO) for the exclusive production of mesons in a very broad range of kinematics. (orig.)

  13. Hard-hat day

    CERN Multimedia

    2003-01-01

    CERN will be organizing a special information day on Friday, 27th June, designed to promote the wearing of hard hats and ensure that they are worn correctly. A new prevention campaign will also be launched.The event will take place in the hall of the Main Building from 11.30 a.m. to 2.00 p.m., when you will be able to come and try on various models of hard hat, including some of the very latest innovative designs, ask questions and pass on any comments and suggestions.

  14. Investigation of microstructural and physical characteristics of nano composite tin oxide-doped Al3+ in Zn2+ based composite coating by DAECD technique

    Science.gov (United States)

    Anawe, P. A. L.; Fayomi, O. S. I.; Popoola, A. P. I.

    In other to overcome the devastating deterioration of mild steel in service, Zn-based embedded Al/SnO2 composite coatings have been considered as reinforcing alternative replacements to the more traditional deposition for improved surface properties by using Dual Anode Electrolytic Co-deposition (DAECD) technique from chloride bath. The structural characterization of the starting materials and deposited coating are evaluated using scanning electron microscopy (SEM), equipped with energy dispersive X-ray spectroscopy (EDX) elemental analysis and atomic force microscope (AFM). The hardness behaviour, wear and intermetallic distribution was examined by diamond based microhardness tester, CETR reciprocating sliding test rig and X-ray diffractometer (XRD) respectively. The corrosion properties of the developed coating were examined in 3.5% NaCl. The microstructure of the deposited sample obtained at 7% SnO2, revealed fine-grains deposit of the Al/SnO2 on the mild steel surface. The results showed that the Al/SnO2 strengthening alloy plays a significant role in impelling the wear and corrosion behaviour of Zn-Al/SnO2 coatings in an aggressive saline environment. Interestingly Zn-30Al-7Sn-chloride showed the highest wear and improved corrosion resistance due to Al/SnO2 oxide passive film that forms during anodic polarization. This work established that co-deposition of mild steel with Al/SnO2 is auspicious in increasing the anti-wear and corrosion progression.

  15. Hard times; Schwere Zeiten

    Energy Technology Data Exchange (ETDEWEB)

    Grunwald, Markus

    2012-10-02

    The prices of silicon and solar wafers keep dropping. According to market research specialist IMS research, this is the result of weak traditional solar markets and global overcapacities. While many manufacturers are facing hard times, big producers of silicon are continuing to expand.

  16. Hardness of Clustering

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Hardness of Clustering. Both k-means and k-medians intractable (when n and d are both inputs even for k =2). The best known deterministic algorithms. are based on Voronoi partitioning that. takes about time. Need for approximation – “close” to optimal.

  17. Rock-hard coatings

    OpenAIRE

    Muller, M.

    2007-01-01

    Aircraft jet engines have to be able to withstand infernal conditions. Extreme heat and bitter cold tax coatings to the limit. Materials expert Dr Ir. Wim Sloof fits atoms together to develop rock-hard coatings. The latest invention in this field is known as ceramic matrix composites. Sloof has signed an agreement with a number of parties to investigate this material further.

  18. Rock-hard coatings

    NARCIS (Netherlands)

    Muller, M.

    2007-01-01

    Aircraft jet engines have to be able to withstand infernal conditions. Extreme heat and bitter cold tax coatings to the limit. Materials expert Dr Ir. Wim Sloof fits atoms together to develop rock-hard coatings. The latest invention in this field is known as ceramic matrix composites. Sloof has

  19. Hardness and excitation energy

    Indian Academy of Sciences (India)

    It is shown that the first excitation energy can be given by the Kohn-Sham hardness (i.e. the energy difference of the ground-state lowest unoccupied and highest occupied levels) plus an extra term coming from the partial derivative of the ensemble exchange-correlation energy with respect to the weighting factor in the ...

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

    Science.gov (United States)

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

    2018-05-01

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

  1. Novel organo soluble poly imides and polyimide nano composites based on 1,4-bis(4-aminophenyl)-1,3,4-oxadiaz olyl)benzene, BAOB, via BAOB-modified organo clay

    International Nuclear Information System (INIS)

    Mansoori, Y.; Darvishi, K.

    2014-01-01

    New, thermally stable poly imides (PI) containing a 1,3,4-oxadiazole ring in the polymer backbone based on 1,4-bis((4-aminophenyl)-1,3,4-oxadiaz olyl)benzene, BAOB, were synthesized. The prepared polymers were soluble in polar and aprotic solvents. The obtained results reveal that within the prepared polymers, polyimide which has been obtained from BAOB and 4,4-oxy diphthalic dianhydride, ODPA, has the most improved thermal properties. In the next part, thermally stable organophilic clay was obtained via cation exchange reaction between sodium montmorillonite (Na-MMT) and the hydrochloride salt of BAOB. Then, a series of PI/clay nano composite materials (PCNs) were synthesized from the in situ polymerization reaction of BAOB and ODPA via thermal imidization, BAOB-MMT was used as the filler at different concentrations. Intercalation of polymer chains within the organo clay galleries was confirmed by W XRD. The glass transition temperature is increased with respect to pristine PI for PCNs 1-3 wt %. At high clay loadings, the aggregation of organo clay particles results in a decrease in T g . In the Sem images of the pure polymer too many micro-cracks were observed in the background, while surface homogeneity of PCN 1 wt % is increased and micro-cracks are reduced. (Author)

  2. Novel organo soluble poly imides and polyimide nano composites based on 1,4-bis(4-aminophenyl)-1,3,4-oxadiaz olyl)benzene, BAOB, via BAOB-modified organo clay

    Energy Technology Data Exchange (ETDEWEB)

    Mansoori, Y.; Darvishi, K., E-mail: ya_mansoori@yahoo.com [University of Mohaghegh Ardabili, Faculty of Science, Department of Applied Chemistry, Daneshgah, Ardabil (Iran, Islamic Republic of)

    2014-10-01

    New, thermally stable poly imides (PI) containing a 1,3,4-oxadiazole ring in the polymer backbone based on 1,4-bis((4-aminophenyl)-1,3,4-oxadiaz olyl)benzene, BAOB, were synthesized. The prepared polymers were soluble in polar and aprotic solvents. The obtained results reveal that within the prepared polymers, polyimide which has been obtained from BAOB and 4,4-oxy diphthalic dianhydride, ODPA, has the most improved thermal properties. In the next part, thermally stable organophilic clay was obtained via cation exchange reaction between sodium montmorillonite (Na-MMT) and the hydrochloride salt of BAOB. Then, a series of PI/clay nano composite materials (PCNs) were synthesized from the in situ polymerization reaction of BAOB and ODPA via thermal imidization, BAOB-MMT was used as the filler at different concentrations. Intercalation of polymer chains within the organo clay galleries was confirmed by W XRD. The glass transition temperature is increased with respect to pristine PI for PCNs 1-3 wt %. At high clay loadings, the aggregation of organo clay particles results in a decrease in T{sub g}. In the Sem images of the pure polymer too many micro-cracks were observed in the background, while surface homogeneity of PCN 1 wt % is increased and micro-cracks are reduced. (Author)

  3. Hard Copy Market Overview

    Science.gov (United States)

    Testan, Peter R.

    1987-04-01

    A number of Color Hard Copy (CHC) market drivers are currently indicating strong growth in the use of CHC technologies for the business graphics marketplace. These market drivers relate to product, software, color monitors and color copiers. The use of color in business graphics allows more information to be relayed than is normally the case in a monochrome format. The communicative powers of full-color computer generated output in the business graphics application area will continue to induce end users to desire and require color in their future applications. A number of color hard copy technologies will be utilized in the presentation graphics arena. Thermal transfer, ink jet, photographic and electrophotographic technologies are all expected to be utilized in the business graphics presentation application area in the future. Since the end of 1984, the availability of color application software packages has grown significantly. Sales revenue generated by business graphics software is expected to grow at a compound annual growth rate of just over 40 percent to 1990. Increased availability of packages to allow the integration of text and graphics is expected. Currently, the latest versions of page description languages such as Postscript, Interpress and DDL all support color output. The use of color monitors will also drive the demand for color hard copy in the business graphics market place. The availability of higher resolution screens is allowing color monitors to be easily used for both text and graphics applications in the office environment. During 1987, the sales of color monitors are expected to surpass the sales of monochrome monitors. Another major color hard copy market driver will be the color copier. In order to take advantage of the communications power of computer generated color output, multiple copies are required for distribution. Product introductions of a new generation of color copiers is now underway with additional introductions expected

  4. Hard Electromagnetic Processes

    International Nuclear Information System (INIS)

    Richard, F.

    1987-09-01

    Among hard electromagnetic processes, I will use the most recent data and focus on quantitative test of QCD. More specifically, I will retain two items: - hadroproduction of direct photons, - Drell-Yan. In addition, I will briefly discuss a recent analysis of ISR data obtained with AFS (Axial Field Spectrometer) which sheds a new light on the e/π puzzle at low P T

  5. Final Report - Recovery Act - Development and application of processing and process control for nano-composite materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, Claus [ORNL; Armstrong, Beth L [ORNL; Maxey, L Curt [ORNL; Sabau, Adrian S [ORNL; Wang, Hsin [ORNL; Hagans, Patrick [A123 Systems, Inc.; Babinec, Sue [A123 Systems, Inc.

    2013-08-01

    parameters such as slurry quality and equipment optimization were examined. Removal of particles and gels by filtering, control of viscosity by %solids and mixing adjustments, removal of trapped gas in the slurry and modification of coater speed and slot die gap were all found to be important for producing uniform and flaw-free coatings. Second, an in-line Hi-Pot testing method has been developed specifically for NCS that will enable detection of coating flaws that could lead to soft or hard electrical shorts within the cell. In this way flawed material can be rejected before incorporation into the cell thus greatly reducing the amount of scrap that is generated. Improved battery safety is an extremely important benefit of NCS. Evaluation of battery safety is usually accomplished by conducting a variety of tests including nail penetration, hot box, over charge, etc. For these tests entire batteries must be built but the resultant temperature and voltage responses reveal little about the breakdown mechanism. In this report is described a pinch test which is used to evaluate NCS quality at various stages including coated anode and cathode as well as assembled cell. Coupled with post-microscopic examination of the damaged pinch point test data can assist in the coating optimization from an improved end-use standpoint. As a result of this work two invention disclosures, one for optimizing drying methodology and the other for an in-line system for flaw detection, have been filed. In addition, 2 papers are being written for submission to peer-reviewed journals.

  6. CRADA Final Report for NFE-08-01826: Development and application of processing and processcontrol for nano-composite materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, C.; Armstrong, B.; Maxey, C.; Sabau, A.; Wang, H.; Hagans, P. (A123 Systems, Inc.); and Babinec, S. (A123 Systems, Inc.)

    2012-12-15

    parameters such as slurry quality and equipment optimization were examined. Removal of particles and gels by filtering, control of viscosity by %solids and mixing adjustments, removal of trapped gas in the slurry and modification of coater speed and slot die gap were all found to be important for producing uniform and flaw-free coatings. Second, an in-line Hi-Pot testing method has been developed specifically for NCS that will enable detection of coating flaws that could lead to soft or hard electrical shorts within the cell. In this way flawed material can be rejected before incorporation into the cell thus greatly reducing the amount of scrap that is generated. Improved battery safety is an extremely important benefit of NCS. Evaluation of battery safety is usually accomplished by conducting a variety of tests including nail penetration, hot box, over charge, etc. For these tests entire batteries must be built but the resultant temperature and voltage responses reveal little about the breakdown mechanism. In this report is described a pinch test which is used to evaluate NCS quality at various stages including coated anode and cathode as well as assembled cell. Coupled with post-microscopic examination of the damaged ‘pinch point’ test data can assist in the coating optimization from an improved end-use standpoint. As a result of this work two invention disclosures, one for optimizing drying methodology and the other for an in-line system for flaw detection, have been filed. In addition, 2 papers are being written for submission to peer-reviewed journals.

  7. Development and characterization of nano structured hard coatings for high performance tools by using PVD technique

    International Nuclear Information System (INIS)

    Irfan, M.; Alam, S.; Hassan, Z.; Iftikhar, F.; Khadim, S.

    2006-01-01

    No doubt hard coatings nave major applications in high performance cutting tools in order to improve tribological and mechanical properties of these tools since last years. The actual top development in this regard is the development of PVD based AlTiN coatings and their supplementation with nano. layers. In present these nano coatings are replaced by nano composites along with an additional development of Multilayer Nano structured coatings. This PVD based nano structured coating development optimized by process parameters, crystalline structure and deposition in multilayer. These coating are definitely produced by combination of ARC and Sputtering with filtration of arc droplets. It is studied that the properties like oxidation resistance, wear resistance and resistance against chemical reaction may be obtained by alloying additions of different elements. This paper presents different development stages and Process parameters for- producing high performance Nanostructure coatings and including adhesion test by using Kalomax system for determination of adhesion strength of these coatings and coating thickness measurements by using image analyzer system. Results and conclusions are showing the optimum values for better coatings for different applications. (author)

  8. Revisiting the definition of local hardness and hardness kernel.

    Science.gov (United States)

    Polanco-Ramírez, Carlos A; Franco-Pérez, Marco; Carmona-Espíndola, Javier; Gázquez, José L; Ayers, Paul W

    2017-05-17

    An analysis of the hardness kernel and local hardness is performed to propose new definitions for these quantities that follow a similar pattern to the one that characterizes the quantities associated with softness, that is, we have derived new definitions for which the integral of the hardness kernel over the whole space of one of the variables leads to local hardness, and the integral of local hardness over the whole space leads to global hardness. A basic aspect of the present approach is that global hardness keeps its identity as the second derivative of energy with respect to the number of electrons. Local hardness thus obtained depends on the first and second derivatives of energy and electron density with respect to the number of electrons. When these derivatives are approximated by a smooth quadratic interpolation of energy, the expression for local hardness reduces to the one intuitively proposed by Meneses, Tiznado, Contreras and Fuentealba. However, when one combines the first directional derivatives with smooth second derivatives one finds additional terms that allow one to differentiate local hardness for electrophilic attack from the one for nucleophilic attack. Numerical results related to electrophilic attacks on substituted pyridines, substituted benzenes and substituted ethenes are presented to show the overall performance of the new definition.

  9. Hard and Soft Governance

    DEFF Research Database (Denmark)

    Moos, Lejf

    2009-01-01

    of Denmark, and finally the third layer: the leadership used in Danish schools. The use of 'soft governance' is shifting the focus of governance and leadership from decisions towards influence and power and thus shifting the focus of the processes from the decision-making itself towards more focus......The governance and leadership at transnational, national and school level seem to be converging into a number of isomorphic forms as we see a tendency towards substituting 'hard' forms of governance, that are legally binding, with 'soft' forms based on persuasion and advice. This article analyses...... and discusses governance forms at several levels. The first layer is the global: the methods of 'soft governance' that are being utilised by transnational agencies. The second layer is the national and local: the shift in national and local governance seen in many countries, but here demonstrated in the case...

  10. Zirconium nitride hard coatings

    International Nuclear Information System (INIS)

    Roman, Daiane; Amorim, Cintia Lugnani Gomes de; Soares, Gabriel Vieira; Figueroa, Carlos Alejandro; Baumvol, Israel Jacob Rabin; Basso, Rodrigo Leonardo de Oliveira

    2010-01-01

    Zirconium nitride (ZrN) nanometric films were deposited onto different substrates, in order to study the surface crystalline microstructure and also to investigate the electrochemical behavior to obtain a better composition that minimizes corrosion reactions. The coatings were produced by physical vapor deposition (PVD). The influence of the nitrogen partial pressure, deposition time and temperature over the surface properties was studied. Rutherford backscattering spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and corrosion experiments were performed to characterize the ZrN hard coatings. The ZrN films properties and microstructure changes according to the deposition parameters. The corrosion resistance increases with temperature used in the films deposition. Corrosion tests show that ZrN coating deposited by PVD onto titanium substrate can improve the corrosion resistance. (author)

  11. Janka hardness using nonstandard specimens

    Science.gov (United States)

    David W. Green; Marshall Begel; William Nelson

    2006-01-01

    Janka hardness determined on 1.5- by 3.5-in. specimens (2×4s) was found to be equivalent to that determined using the 2- by 2-in. specimen specified in ASTM D 143. Data are presented on the relationship between Janka hardness and the strength of clear wood. Analysis of historical data determined using standard specimens indicated no difference between side hardness...

  12. Graphene reinforced alumina nano-composites

    Czech Academy of Sciences Publication Activity Database

    Porwal, H.; Tatarko, Peter; Grasso, S.; Khaliq, J.; Dlouhý, Ivo; Reece, M.J.

    2013-01-01

    Roč. 64, NOV (2013), s. 359-369 ISSN 0008-6223 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 EU Projects: European Commission(XE) 264526 - GLACERCO Institutional support: RVO:68081723 Keywords : fracture toughness determination * ceramic-matrix composites * carbon nanotubes Subject RIV: JI - Composite Materials Impact factor: 6.160, year: 2013

  13. Cirrus Dopant Nano-Composite Coatings

    Science.gov (United States)

    2014-11-01

    coatings without alteration to the existing plating process. Glen Slater, Cirrus Materials | Stephen Flint, Auckland UniServices Ltd Report...ADDRESS(ES) University of Auckland ,Cirrus Materials, Auckland , New Zealand, 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY...JiA/ g THE UNIVERSITY ’-" OF AUCKLAND NEW ZEALAND Te Whare Wanan a o Thmaki Makaurau ~"""’ • ........,." ... Southwest Pacific Basin . p

  14. 2TB hard disk drive

    CERN Multimedia

    This particular object was used up until 2012 in the Data Centre. It slots into one of the Disk Server trays. Hard disks were invented in the 1950s. They started as large disks up to 20 inches in diameter holding just a few megabytes (link is external). They were originally called "fixed disks" or "Winchesters" (a code name used for a popular IBM product). They later became known as "hard disks" to distinguish them from "floppy disks (link is external)." Hard disks have a hard platter that holds the magnetic medium, as opposed to the flexible plastic film found in tapes and floppies.

  15. Hard processes. Vol. 1

    International Nuclear Information System (INIS)

    Ioffe, B.L.; Khoze, V.A.; Lipatov, L.N.

    1984-01-01

    Deep inelastic (hard) processes are now at the epicenter of modern high-energy physics. These processes are governed by short-distance dynamics, which reveals the intrinsic structure of elementary particles. The theory of deep inelastic processes is now sufficiently well settled. The authors' aim was to give an effective tool to theoreticians and experimentalists who are engaged in high-energy physics. This book is intended primarily for physicists who are only beginning to study the field. To read the book, one should be acquainted with the Feynman diagram technique and with some particular topics from elementary particle theory (symmetries, dispersion relations, Regge pole theory, etc.). Theoretical consideration of deep inelastic processes is now based on quantum chromodynamics (QCD). At the same time, analysis of relevant physical phenomena demands a synthesis of QCD notions (quarks, gluons) with certain empirical characteristics. Therefore, the phenomenological approaches presented are a necessary stage in a study of this range of phenomena which should undoubtedly be followed by a detailed description based on QCD and electroweak theory. The authors were naturally unable to dwell on experimental data accumulated during the past decade of intensive investigations. Priority was given to results which allow a direct comparison with theoretical predictions. (Auth.)

  16. Hard coal; Steinkohle

    Energy Technology Data Exchange (ETDEWEB)

    Loo, Kai van de; Sitte, Andreas-Peter [Gesamtverband Steinkohle e.V. (GVSt), Herne (Germany)

    2015-07-01

    International the coal market in 2014 was the first time in a long time in a period of stagnation. In Germany, the coal consumption decreased even significantly, mainly due to the decrease in power generation. Here the national energy transition has now been noticable affected negative for coal use. The political guidances can expect a further significant downward movement for the future. In the present phase-out process of the German hard coal industry with still three active mines there was in 2014 no decommissioning. But the next is at the end of 2015, and the plans for the time after mining have been continued. [German] International war der Markt fuer Steinkohle 2014 erstmals seit langem wieder von einer Stagnation gekennzeichnet. In Deutschland ging der Steinkohlenverbrauch sogar deutlich zurueck, vor allem wegen des Rueckgangs in der Stromerzeugung. Hier hat sich die nationale Energiewende nun spuerbar und fuer die Steinkohlennutzung negativ ausgewirkt. Die politischen Weichenstellungen lassen fuer die Zukunft eine weitere erhebliche Abwaertsbewegung erwarten. Bei dem im Auslaufprozess befindlichen deutschen Steinkohlenbergbau mit noch drei aktiven Bergwerken gab es 2014 keine Stilllegung. Doch die naechste steht zum Jahresende 2015 an, und die Planungen fuer die Zeit nach dem Bergbau sind fortgefuehrt worden.

  17. Melting of polydisperse hard disks

    NARCIS (Netherlands)

    Pronk, S.; Frenkel, D.

    2004-01-01

    The melting of a polydisperse hard-disk system is investigated by Monte Carlo simulations in the semigrand canonical ensemble. This is done in the context of possible continuous melting by a dislocation-unbinding mechanism, as an extension of the two-dimensional hard-disk melting problem. We find

  18. Structural, dielectric and ferroelectric studies of (x) Mg{sub 0.25}Cu{sub 0.25}Zn{sub 0.5}Fe{sub 2}O{sub 4} + (1-x) BaTiO{sub 3} magnetoelectric nano-composites

    Energy Technology Data Exchange (ETDEWEB)

    Khader, S. Abdul, E-mail: khadersku@gmail.com; Sankarappa, T., E-mail: sankarappa@rediffmail.com [Department of Physics, Gulbarga University, Gulbarga-585106, Karnataka (India); Muneeswaran, M.; Giridharan, N. V. [Department of Physics, National Institute of Technology, Tiruchirapalli-620015 (India)

    2016-05-06

    The Particulate nano-composites of ferrite and ferroelectric phases having the general formula (x) Mg{sub 0.25}Cu{sub 0.25}Zn{sub 0.5}Fe{sub 2}O{sub 4} + (1-x) BaTiO{sub 3} (x=15%, 30% and 45%) were synthesized by sintering mixtures of highly ferroelectric BaTiO{sub 3} (BT) and highly magneto-strictive magnetic component Mg{sub 0.25}Cu{sub 0.25}Zn{sub 0.5}Fe{sub 2}O{sub 4}(MCZF). The presence of constituent phases of ferrite, ferroelectric and their composites were probed and confirmed by X-ray diffraction (XRD) studies. Surface morphology of the samples has been investigated using Field Emission Scanning Electron Microscope (FESEM). The variation of dielectric constant and dissipation factor as a function of frequency from 100 Hz to 1 MHz at room temperature were carried out using a Hioki LCR Hi-Tester. The dielectric constant and dielectric loss were found to decrease rapidly in the low frequency region and became almost constant in the high frequency region. The electrical conductivity deduced from the measured dielectric data has been thoroughly analyzed and found that the conduction mechanism in these composites is in conformity with small polaron hopping model. The ferroelectric properties of synthesized magneto-electric nano-composites were measured using P-E loop tracer.

  19. Hardness variability in commercial technologies

    International Nuclear Information System (INIS)

    Shaneyfelt, M.R.; Winokur, P.S.; Meisenheimer, T.L.; Sexton, F.W.; Roeske, S.B.; Knoll, M.G.

    1994-01-01

    The radiation hardness of commercial Floating Gate 256K E 2 PROMs from a single diffusion lot was observed to vary between 5 to 25 krad(Si) when irradiated at a low dose rate of 64 mrad(Si)/s. Additional variations in E 2 PROM hardness were found to depend on bias condition and failure mode (i.e., inability to read or write the memory), as well as the foundry at which the part was manufactured. This variability is related to system requirements, and it is shown that hardness level and variability affect the allowable mode of operation for E 2 PROMs in space applications. The radiation hardness of commercial 1-Mbit CMOS SRAMs from Micron, Hitachi, and Sony irradiated at 147 rad(Si)/s was approximately 12, 13, and 19 krad(Si), respectively. These failure levels appear to be related to increases in leakage current during irradiation. Hardness of SRAMs from each manufacturer varied by less than 20%, but differences between manufacturers are significant. The Qualified Manufacturer's List approach to radiation hardness assurance is suggested as a way to reduce variability and to improve the hardness level of commercial technologies

  20. On scale dependence of hardness

    International Nuclear Information System (INIS)

    Shorshorov, M.Kh.; Alekhin, V.P.; Bulychev, S.I.

    1977-01-01

    The concept of hardness as a structure-sensitive characteristic of a material is considered. It is shown that in conditions of a decreasing stress field under the inventor the hardness function is determined by the average distance, Lsub(a), between the stops (fixed and sessile dislocations, segregation particles, etc.). In the general case, Lsub(a) depends on the size of the impression and explains the great diversity of hardness functions. The concept of average true deformation rate on depression is introduced

  1. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Research results of hard photon technology have been summarized as a part of novel technology development highly utilizing the quantum nature of photon. Hard photon technology refers to photon beam technologies which use photon in the 0.1 to 200 nm wavelength region. Hard photon has not been used in industry due to the lack of suitable photon sources and optical devices. However, hard photon in this wavelength region is expected to bring about innovations in such areas as ultrafine processing and material synthesis due to its atom selective reaction, inner shell excitation reaction, and spatially high resolution. Then, technological themes and possibility have been surveyed. Although there are principle proposes and their verification of individual technologies for the technologies of hard photon generation, regulation and utilization, they are still far from the practical applications. For the photon source technology, the laser diode pumped driver laser technology, laser plasma photon source technology, synchrotron radiation photon source technology, and vacuum ultraviolet photon source technology are presented. For the optical device technology, the multi-layer film technology for beam mirrors and the non-spherical lens processing technology are introduced. Also are described the reduction lithography technology, hard photon excitation process, and methods of analysis and measurement. 430 refs., 165 figs., 23 tabs.

  2. Hard diffraction and rapidity gaps

    International Nuclear Information System (INIS)

    Brandt, A.

    1995-09-01

    The field of hard diffraction, which studies events with a rapidity gap and a hard scattering, has expanded dramatically recently. A review of new results from CDF, D OE, H1 and ZEUS will be given. These results include diffractive jet production, deep-inelastic scattering in large rapidity gap events, rapidity gaps between high transverse energy jets, and a search for diffractive W-boson production. The combination of these results gives new insight into the exchanged object, believed to be the pomeron. The results axe consistent with factorization and with a hard pomeron that contains both quarks and gluons. There is also evidence for the exchange of a strongly interacting color singlet in high momentum transfer (36 2 ) events

  3. Initiative hard coal; Initiative Steinkohle

    Energy Technology Data Exchange (ETDEWEB)

    Leonhardt, J.

    2007-08-02

    In order to decrease the import dependence of hard coal in the European Union, the author has submitted suggestions to the director of conventional sources of energy (directorate general for energy and transport) of the European community, which found a positive resonance. These suggestions are summarized in an elaboration 'Initiative Hard Coal'. After clarifying the starting situation and defining the target the presupposition for a better use of hard coal deposits as raw material in the European Union are pointed out. On that basis concrete suggestions for measures are made. Apart from the conditions of the deposits it concerns thereby also new mining techniques and mining-economical developments, connected with tasks for the mining-machine industry. (orig.)

  4. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    For the application of photon to industrial technologies, in particular, a hard photon technology was surveyed which uses photon beams of 0.1-200nm in wavelength. Its features such as selective atom reaction, dense inner shell excitation and spacial high resolution by quantum energy are expected to provide innovative techniques for various field such as fine machining, material synthesis and advanced inspection technology. This wavelength region has been hardly utilized for industrial fields because of poor development of suitable photon sources and optical devices. The developmental meaning, usable time and issue of a hard photon reduction lithography were surveyed as lithography in ultra-fine region below 0.1{mu}m. On hard photon analysis/evaluation technology, the industrial use of analysis, measurement and evaluation technologies by micro-beam was viewed, and optimum photon sources and optical systems were surveyed. Prediction of surface and surface layer modification by inner shell excitation, the future trend of this process and development of a vacuum ultraviolet light source were also surveyed. 383 refs., 153 figs., 17 tabs.

  5. Evaluation of hard fossil fuel

    International Nuclear Information System (INIS)

    Zivkovic, S.; Nuic, J.

    1999-01-01

    Because of its inexhaustible supplies hard fossil fuel will represent the pillar of the power systems of the 21st century. Only high-calorie fossil fuels have the market value and participate in the world trade. Low-calorie fossil fuels ((brown coal and lignite) are fuels spent on the spot and their value is indirectly expressed through manufactured kWh. For the purpose of determining the real value of a tonne of low-calorie coal, the criteria that help in establishing the value of a tonne of hard coal have to be corrected and thus evaluated and assessed at the market. (author)

  6. Calorimeter triggers for hard collisions

    International Nuclear Information System (INIS)

    Landshoff, P.V.; Polkinghorne, J.C.

    1978-01-01

    We discuss the use of a forward calorimeter to trigger on hard hadron-hadron collisions. We give a derivation in the covariant parton model of the Ochs-Stodolsky scaling law for single-hard-scattering processes, and investigate the conditions when instead a multiple- scattering mechanism might dominate. With a proton beam, this mechanism results in six transverse jets, with a total average multiplicity about twice that seen in ordinary events. We estimate that its cross section is likely to be experimentally accessible at avalues of the beam energy in the region of 100 GeV/c

  7. Hardness of ion implanted ceramics

    International Nuclear Information System (INIS)

    Oliver, W.C.; McHargue, C.J.; Farlow, G.C.; White, C.W.

    1985-01-01

    It has been established that the wear behavior of ceramic materials can be modified through ion implantation. Studies have been done to characterize the effect of implantation on the structure and composition of ceramic surfaces. To understand how these changes affect the wear properties of the ceramic, other mechanical properties must be measured. To accomplish this, a commercially available ultra low load hardness tester has been used to characterize Al 2 O 3 with different implanted species and doses. The hardness of the base material is compared with the highly damaged crystalline state as well as the amorphous material

  8. Chemical hardness and density functional theory

    Indian Academy of Sciences (India)

    Unknown

    RALPH G PEARSON. Chemistry Department, University of California, Santa Barbara, CA 93106, USA. Abstract. The concept of chemical hardness is reviewed from a personal point of view. Keywords. Hardness; softness; hard & soft acids bases (HSAB); principle of maximum hardness. (PMH) density functional theory (DFT) ...

  9. Seismic signals hard clipping overcoming

    Science.gov (United States)

    Olszowa, Paula; Sokolowski, Jakub

    2018-01-01

    In signal processing the clipping is understand as the phenomenon of limiting the signal beyond certain threshold. It is often related to overloading of a sensor. Two particular types of clipping are being recognized: soft and hard. Beyond the limiting value soft clipping reduces the signal real gain while the hard clipping stiffly sets the signal values at the limit. In both cases certain amount of signal information is lost. Obviously if one possess the model which describes the considered signal and the threshold value (which might be slightly more difficult to obtain in the soft clipping case), the attempt of restoring the signal can be made. Commonly it is assumed that the seismic signals take form of an impulse response of some specific system. This may lead to belief that the sine wave may be the most appropriate to fit in the clipping period. However, this should be tested. In this paper the possibility of overcoming the hard clipping in seismic signals originating from a geoseismic station belonging to an underground mine is considered. A set of raw signals will be hard-clipped manually and then couple different functions will be fitted and compared in terms of least squares. The results will be then analysed.

  10. Hard equality constrained integer knapsacks

    NARCIS (Netherlands)

    Aardal, K.I.; Lenstra, A.K.; Cook, W.J.; Schulz, A.S.

    2002-01-01

    We consider the following integer feasibility problem: "Given positive integer numbers a 0, a 1,..., a n, with gcd(a 1,..., a n) = 1 and a = (a 1,..., a n), does there exist a nonnegative integer vector x satisfying ax = a 0?" Some instances of this type have been found to be extremely hard to solve

  11. Stress in hard metal films

    NARCIS (Netherlands)

    Janssen, G.C.A.M.; Kamminga, J.D.

    2004-01-01

    In the absence of thermal stress, tensile stress in hard metal films is caused by grain boundary shrinkage and compressive stress is caused by ion peening. It is shown that the two contributions are additive. Moreover tensile stress generated at the grain boundaries does not relax by ion

  12. Hard processes in hadronic interactions

    International Nuclear Information System (INIS)

    Satz, H.; Wang, X.N.

    1995-01-01

    Quantum chromodynamics is today accepted as the fundamental theory of strong interactions, even though most hadronic collisions lead to final states for which quantitative QCD predictions are still lacking. It therefore seems worthwhile to take stock of where we stand today and to what extent the presently available data on hard processes in hadronic collisions can be accounted for in terms of QCD. This is one reason for this work. The second reason - and in fact its original trigger - is the search for the quark-gluon plasma in high energy nuclear collisions. The hard processes to be considered here are the production of prompt photons, Drell-Yan dileptons, open charm, quarkonium states, and hard jets. For each of these, we discuss the present theoretical understanding, compare the resulting predictions to available data, and then show what behaviour it leads to at RHIC and LHC energies. All of these processes have the structure mentioned above: they contain a hard partonic interaction, calculable perturbatively, but also the non-perturbative parton distribution within a hadron. These parton distributions, however, can be studied theoretically in terms of counting rule arguments, and they can be checked independently by measurements of the parton structure functions in deep inelastic lepton-hadron scattering. The present volume is the work of Hard Probe Collaboration, a group of theorists who are interested in the problem and were willing to dedicate a considerable amount of their time and work on it. The necessary preparation, planning and coordination of the project were carried out in two workshops of two weeks' duration each, in February 1994 at CERn in Geneva andin July 1994 at LBL in Berkeley

  13. Hard-to-fill vacancies.

    Science.gov (United States)

    Williams, Ruth

    2010-09-29

    Skills for Health has launched a set of resources to help healthcare employers tackle hard-to-fill entry-level vacancies and provide sustainable employment for local unemployed people. The Sector Employability Toolkit aims to reduce recruitment and retention costs for entry-level posts and repare people for employment through pre-job training programmes, and support employers to develop local partnerships to gain access to wider pools of candidates and funding streams.

  14. Pushing hard on the accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1987-09-15

    The quest for new techniques to drive future generations of particle accelerators has been pushed hard in recent years, efforts having been highlighted by workshops in Europe, organized by the European Committee for Future Accelerators, and in the US. The latest ECFA Workshop on New Developments in Particle Acceleration Techniques, held at Orsay from 29 June to 4 July, showed how the initial frantic search for innovation is now maturing.

  15. CMS results on hard diffraction

    CERN Document Server

    INSPIRE-00107098

    2013-01-01

    In these proceedings we present CMS results on hard diffraction. Diffractive dijet production in pp collisions at $\\sqrt{s}$=7 TeV is discussed. The cross section for dijet production is presented as a function of $\\tilde{\\xi}$, representing the fractional momentum loss of the scattered proton in single-diffractive events. The observation of W and Z boson production in events with a large pseudo-rapidity gap is also presented.

  16. Playing Moderately Hard to Get

    Directory of Open Access Journals (Sweden)

    Stephen Reysen

    2013-12-01

    Full Text Available In two studies, we examined the effect of different degrees of attraction reciprocation on ratings of attraction toward a potential romantic partner. Undergraduate college student participants imagined a potential romantic partner who reciprocated a low (reciprocating attraction one day a week, moderate (reciprocating attraction three days a week, high (reciprocating attraction five days a week, or unspecified degree of attraction (no mention of reciprocation. Participants then rated their degree of attraction toward the potential partner. The results of Study 1 provided only partial support for Brehm’s emotion intensity theory. However, after revising the high reciprocation condition vignette in Study 2, supporting Brehm’s emotion intensity theory, results show that a potential partners’ display of reciprocation of attraction acted as a deterrent to participants’ intensity of experienced attraction to the potential partner. The results support the notion that playing moderately hard to get elicits more intense feelings of attraction from potential suitors than playing too easy or too hard to get. Discussion of previous research examining playing hard to get is also re-examined through an emotion intensity theory theoretical lens.

  17. CMOS optimization for radiation hardness

    International Nuclear Information System (INIS)

    Derbenwick, G.F.; Fossum, J.G.

    1975-01-01

    Several approaches to the attainment of radiation-hardened MOS circuits have been investigated in the last few years. These have included implanting the SiO 2 gate insulator with aluminum, using chrome-aluminum layered gate metallization, using Al 2 O 3 as the gate insulator, and optimizing the MOS fabrication process. Earlier process optimization studies were restricted primarily to p-channel devices operating with negative gate biases. Since knowledge of the hardness dependence upon processing and design parameters is essential in producing hardened integrated circuits, a comprehensive investigation of the effects of both process and design optimization on radiation-hardened CMOS integrated circuits was undertaken. The goals are to define and establish a radiation-hardened processing sequence for CMOS integrated circuits and to formulate quantitative relationships between process and design parameters and the radiation hardness. Using these equations, the basic CMOS design can then be optimized for radiation hardness and some understanding of the basic physics responsible for the radiation damage can be gained. Results are presented

  18. Impact of aging on radiation hardness

    International Nuclear Information System (INIS)

    Shaneyfelt, M.R.; Winokur, P.S.; Fleetwood, D.M.

    1997-01-01

    Burn-in effects are used to demonstrate the potential impact of thermally activated aging effects on functional and parametric radiation hardness. These results have implications on hardness assurance testing. Techniques for characterizing aging effects are proposed

  19. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... Quitting drugs is hard because addiction is a brain disease. Your brain is like a control tower that sends out ... and choices. Addiction changes the signals in your brain and makes it hard to feel OK without ...

  20. Liquid phase surface melting of AA8011 aluminum alloy by addition of Al/Al{sub 2}O{sub 3} nano-composite powders synthesized by high-energy milling

    Energy Technology Data Exchange (ETDEWEB)

    Sohi, M. Heydarzadeh [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Hojjatzadeh, S.M.H., E-mail: Hojatzadeh@yahoo.com [Department of Welding, Science and Research Branch, Azad University, Tehran (Iran, Islamic Republic of); Moosavifar, Sh. S.; Heshmati-Manesh, S. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

    2014-09-15

    Highlights: • Aluminum matrix composite layers reinforced with alumina particles were fabricated. • Non milled powders caused porosity in the microstructures because of poor wettability. • The ball milling of powders was significantly improved the wettability of nano ceramic particles. • The micro hardness of the layers was approximately 3 times greater than that of the base metal. - Abstract: Poor wettability of particles is an obstacle in formation of sound composite layer via surface melting. Pre-coating of particles with metallic material by different techniques, such as ball milling may enhance the wettability of the particles with molten metal. In this study, composite surface layers containing Al{sub 2}O{sub 3} particles were fabricated on the surface of AA8011 aluminum substrates by tungsten inert gas (TIG) surface melting using preplaced layers of Al/Al{sub 2}O{sub 3} powder mixtures in two different forms: (1) a mixture of 40 wt% Al and 60 wt% of 50 nm Al{sub 2}O{sub 3} powders and (2) a mixture obtained by mechanical alloying of 40 wt% Al and 60 wt% of 60 μm Al{sub 2}O{sub 3} powders. Morphology evolution of powders during ball milling and the microstructure of the fabricated composite layers were studied through conventional characterization techniques, such as optical microscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). Microhardness measurements were also performed across the alloyed zone. The results indicated that the layer fabricated by the second route showed a defect free structure with a more uniform distribution of Al{sub 2}O{sub 3} particles in comparison with the layer obtained by the first route. It was also noticed that the uniform dispersion of Al{sub 2}O{sub 3} particles in the fabricated layer increased the hardness to 133 HV which was over 3 times of that of the base metal.

  1. The hard problem of cooperation.

    Directory of Open Access Journals (Sweden)

    Kimmo Eriksson

    Full Text Available Based on individual variation in cooperative inclinations, we define the "hard problem of cooperation" as that of achieving high levels of cooperation in a group of non-cooperative types. Can the hard problem be solved by institutions with monitoring and sanctions? In a laboratory experiment we find that the answer is affirmative if the institution is imposed on the group but negative if development of the institution is left to the group to vote on. In the experiment, participants were divided into groups of either cooperative types or non-cooperative types depending on their behavior in a public goods game. In these homogeneous groups they repeatedly played a public goods game regulated by an institution that incorporated several of the key properties identified by Ostrom: operational rules, monitoring, rewards, punishments, and (in one condition change of rules. When change of rules was not possible and punishments were set to be high, groups of both types generally abided by operational rules demanding high contributions to the common good, and thereby achieved high levels of payoffs. Under less severe rules, both types of groups did worse but non-cooperative types did worst. Thus, non-cooperative groups profited the most from being governed by an institution demanding high contributions and employing high punishments. Nevertheless, in a condition where change of rules through voting was made possible, development of the institution in this direction was more often voted down in groups of non-cooperative types. We discuss the relevance of the hard problem and fit our results into a bigger picture of institutional and individual determinants of cooperative behavior.

  2. The hard problem of cooperation.

    Science.gov (United States)

    Eriksson, Kimmo; Strimling, Pontus

    2012-01-01

    Based on individual variation in cooperative inclinations, we define the "hard problem of cooperation" as that of achieving high levels of cooperation in a group of non-cooperative types. Can the hard problem be solved by institutions with monitoring and sanctions? In a laboratory experiment we find that the answer is affirmative if the institution is imposed on the group but negative if development of the institution is left to the group to vote on. In the experiment, participants were divided into groups of either cooperative types or non-cooperative types depending on their behavior in a public goods game. In these homogeneous groups they repeatedly played a public goods game regulated by an institution that incorporated several of the key properties identified by Ostrom: operational rules, monitoring, rewards, punishments, and (in one condition) change of rules. When change of rules was not possible and punishments were set to be high, groups of both types generally abided by operational rules demanding high contributions to the common good, and thereby achieved high levels of payoffs. Under less severe rules, both types of groups did worse but non-cooperative types did worst. Thus, non-cooperative groups profited the most from being governed by an institution demanding high contributions and employing high punishments. Nevertheless, in a condition where change of rules through voting was made possible, development of the institution in this direction was more often voted down in groups of non-cooperative types. We discuss the relevance of the hard problem and fit our results into a bigger picture of institutional and individual determinants of cooperative behavior.

  3. Hard electroproduction of hybrid mesons

    International Nuclear Information System (INIS)

    Anikin, I.V.; LPT Universite Paris-Sud, Orsay; Szymanowski, L.; Teryaev, O.V.; ); Wallon, S.

    2005-01-01

    We estimate the sizeable cross section for deep exclusive electroproduction of an exotic J PC = 1 -+ hybrid meson in the Bjorken regime. The production amplitude scales like the one for usual meson electroproduction, i.e. as 1/Q 2 . This is due to the non-vanishing leading twist distribution amplitude for the hybrid meson, which may be normalized thanks to its relation to the energy momentum tensor and to the QCD sum rules technique. The hard amplitude is considered up to next-to-leading order in as and we explore the consequences of fixing the renormalization scale ambiguity through the BLM procedure. (author)

  4. Hard Identity and Soft Identity

    Directory of Open Access Journals (Sweden)

    Hassan Rachik

    2006-04-01

    Full Text Available Often collective identities are classified depending on their contents and rarely depending on their forms. Differentiation between soft identity and hard identity is applied to diverse collective identities: religious, political, national, tribal ones, etc. This classification is made following the principal dimensions of collective identities: type of classification (univocal and exclusive or relative and contextual, the absence or presence of conflictsof loyalty, selective or totalitarian, objective or subjective conception, among others. The different characteristics analysed contribute to outlining an increasingly frequent type of identity: the authoritarian identity.

  5. Aespoe hard rock laboratory Sweden

    International Nuclear Information System (INIS)

    1992-01-01

    The aim of the new Aespoe hard rock laboratory is to demonstrate state of the art of technology and evaluation methods before the start of actual construction work on the planned deep repository for spent nuclear fuel. The nine country OECD/NEA project in the Stripa mine in Sweden has been an excellent example of high quality international research co-operation. In Sweden the new Aespoe hard rock laboratory will gradually take over and finalize this work. SKB very much appreciates the continued international participation in Aespoe which is of great value for the quality efficiency, and confidence in this kind of work. We have invited a number of leading experts to this first international seminar to summarize the current state of a number of key questions. The contributions show the great progress that has taken place during the years. The results show that there is a solid scientific basis for using this knowledge on site specific preparation and work on actual repositories. (au)

  6. Development of radiation hard scintillators

    International Nuclear Information System (INIS)

    Markley, F.; Woods, D.; Pla-Dalmau, A.; Foster, G.; Blackburn, R.

    1992-05-01

    Substantial improvements have been made in the radiation hardness of plastic scintillators. Cylinders of scintillating materials 2.2 cm in diameter and 1 cm thick have been exposed to 10 Mrads of gamma rays at a dose rate of 1 Mrad/h in a nitrogen atmosphere. One of the formulations tested showed an immediate decrease in pulse height of only 4% and has remained stable for 12 days while annealing in air. By comparison a commercial PVT scintillator showed an immediate decrease of 58% and after 43 days of annealing in air it improved to a 14% loss. The formulated sample consisted of 70 parts by weight of Dow polystyrene, 30 pbw of pentaphenyltrimethyltrisiloxane (Dow Corning DC 705 oil), 2 pbw of p-terphenyl, 0.2 pbw of tetraphenylbutadiene, and 0.5 pbw of UVASIL299LM from Ferro

  7. Soft And Hard Skills of Social Worker

    OpenAIRE

    HANTOVÁ, Libuše

    2011-01-01

    The work deals with soft and hard skills relevant to the profession of social worker. The theoretical part at first evaluates and analyzes important soft and hard skills necessary for people working in the field of social work. Then these skills are compared. The practical part illustrates the use of soft and hard skills in practice by means of model scenes and deals with the preferences in three groups of people ? students of social work, social workers and people outside the sphere, namely ...

  8. Theory of hard diffraction and rapidity gaps

    International Nuclear Information System (INIS)

    Del Duca, V.

    1995-06-01

    In this talk we review the models describing the hard diffractive production of jets or more generally high-mass states in presence of rapidity gaps in hadron-hadron and lepton-hadron collisions. By rapidity gaps we mean regions on the lego plot in (pseudo)-rapidity and azimuthal angle where no hadrons are produced, between the jet(s) and an elastically scattered hadron (single hard diffraction) or between two jets (double hard diffraction). (orig.)

  9. Theory of hard diffraction and rapidity gaps

    International Nuclear Information System (INIS)

    Del Duca, V.

    1996-01-01

    In this talk we review the models describing the hard diffractive production of jets or more generally high-mass states in presence of rapidity gaps in hadron-hadron and lepton-hadron collisions. By rapidity gaps we mean regions on the lego plot in (pseudo)-rapidity and azimuthal angle where no hadrons are produced, between the jet(s) and an elastically scattered hadron (single hard diffraction) or between two jets (double hard diffraction). copyright 1996 American Institute of Physics

  10. Advances in hard nucleus cataract surgery

    Directory of Open Access Journals (Sweden)

    Wei Cui

    2013-11-01

    Full Text Available Security and perfect vision and fewer complications are our goals in cataract surgery, and hard-nucleus cataract surgery is always a difficulty one. Many new studies indicate that micro-incision phacoemulsification in treating hard nucleus cataract is obviously effective. This article reviews the evolution process of hard nuclear cataract surgery, the new progress in the research of artificial intraocular lens for microincision, and analyse advantages and disadvantages of various surgical methods.

  11. 30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Distinctively colored hard hats, or hard caps... STANDARDS-UNDERGROUND COAL MINES Miscellaneous § 75.1720-1 Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

  12. 30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Distinctively colored hard hats or hard caps... Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color from those worn by experienced miners shall be worn at...

  13. Hard disks with SCSI interface

    CERN Document Server

    Denisov, O Yu

    1999-01-01

    The testing of 20 models of hard SCSI-disks is carried out: the Fujitsu MAE3091LP; the IBM DDRS-39130, DGHS-318220, DNES-318350, DRHS-36V and DRVS-18V; the Quantum Atlas VI 18.2; the Viking 11 9.1; the Seagate ST118202LW, ST118273LW, ST118273W, ST318203LW, ST318275LW, ST34520W, ST39140LW and ST39173W; and the Western Digital WDE9100-0007, WDE9100-AV0016, WDE9100-AV0030 and WDE9180-0048. All tests ran under the Windows NT 4.0 workstation operating system with Service Pack 4, under video mode with 1024*768 pixel resolution, 32- bit colour depth and V-frequency equal to 85 Hz. The detailed description and characteristics of SCSI stores are presented. Test results (ZD Winstone 99 and ZD WinBench 99 tests) are given in both table and diagram (disk transfer rate) forms. (0 refs).

  14. Development of a hard microcontroller

    International Nuclear Information System (INIS)

    Measel, P.R.; Sivo, L.L.; Quilitz, W.E.; Davidson, T.K.

    1976-01-01

    The applicability of commercially available microprocessors to certain systems requiring radiation survival was assessed. A microcontroller was designed and built to perform a monitor and control function of military operational ground equipment, and demonstrated to exceed the radiation hardness goal. The preparation of the microcontroller module required hardware and software design, selection of LSI and other piece part types, development of piece part and module electrical and radiation test techniques, and the performance of radiation tests on the LSI piece parts and the completed module. The microcontroller has a 16-bit central processor unit, a 4096 word read only memory, and a 256 word read-write memory. The module has circumvention circuitry, including a PIN diode radiation detector. The processor device used was the MMI 6701 T 2 L Schottky bipolar 4-bit slice. Electrical exerciser circuits were developed for in-situ electrical testing of microprocessors and memories during irradiation. A test program was developed for a Terradyne J283 microcircuit tester for more complete electrical characterization of the MMI 6701 microprocessor. A simple self-test algorithm was used in the microcontroller for performance testing during irradiation. For the operational demonstration of the microcontroller a TI 960A minicomputer was used to provide the required complex inputs to the module and verify the module outputs

  15. Complex technique for materials hardness measurement

    Energy Technology Data Exchange (ETDEWEB)

    Krashchenko, V P; Oksametnaya, O B

    1984-01-01

    A review of existing methods of measurement of material hardness in national and foreign practice has been made. A necessity of improving the technique of material hardness measurement in a wide temperature range and insuring load change with indenting, continuity of imprint application, smooth changing of temperatures along a sample length, and deformation rate control has been noted.

  16. Hard scattering and a diffractive trigger

    International Nuclear Information System (INIS)

    Berger, E.L.; Collins, J.C.; Soper, D.E.; Sterman, G.

    1986-02-01

    Conclusions concerning the properties of hard scattering in diffractively produced systems are summarized. One motivation for studying diffractive hard scattering is to investigate the interface between Regge theory and perturbative QCD. Another is to see whether diffractive triggering can result in an improvement in the signal-to-background ratio of measurements of production of very heavy quarks. 5 refs

  17. ERRATUM: Work smart, wear your hard hat

    CERN Multimedia

    2003-01-01

    An error appeared in the article «Work smart, wear your hard hat» published in Weekly Bulletin 27/2003, page 5. The impact which pierced a hole in the hard hat worn by Gerd Fetchenhauer was the equivalent of a box weighing 5 kg and not 50 kg.

  18. 7 CFR 201.57 - Hard seeds.

    Science.gov (United States)

    2010-01-01

    ... REGULATIONS Germination Tests in the Administration of the Act § 201.57 Hard seeds. Seeds which remain hard at the end of the prescribed test because they have not absorbed water, due to an impermeable seed coat... percentage of germination. For flatpea, continue the swollen seed in test for 14 days when germinating at 15...

  19. Thermal spray coatings replace hard chrome

    International Nuclear Information System (INIS)

    Schroeder, M.; Unger, R.

    1997-01-01

    Hard chrome plating provides good wear and erosion resistance, as well as good corrosion protection and fine surface finishes. Until a few years ago, it could also be applied at a reasonable cost. However, because of the many environmental and financial sanctions that have been imposed on the process over the past several years, cost has been on a consistent upward trend, and is projected to continue to escalate. Therefore, it is very important to find a coating or a process that offers the same characteristics as hard chrome plating, but without the consequent risks. This article lists the benefits and limitations of hard chrome plating, and describes the performance of two thermal spray coatings (tungsten carbide and chromium carbide) that compared favorably with hard chrome plating in a series of tests. It also lists three criteria to determine whether plasma spray or hard chrome plating should be selected

  20. Correlating particle hardness with powder compaction performance.

    Science.gov (United States)

    Cao, Xiaoping; Morganti, Mikayla; Hancock, Bruno C; Masterson, Victoria M

    2010-10-01

    Assessing particle mechanical properties of pharmaceutical materials quickly and with little material can be very important to early stages of pharmaceutical research. In this study, a wide range of pharmaceutical materials were studied using atomic force microscopy (AFM) nanoindentation. A significant amount of particle hardness and elastic modulus data were provided. Moreover, powder compact mechanical properties of these materials were investigated in order to build correlation between the particle hardness and powder compaction performance. It was found that the materials with very low or high particle hardness most likely exhibit poor compaction performance while the materials with medium particle hardness usually have good compaction behavior. Additionally, the results from this study enriched Hiestand's special case concept on particle hardness and powder compaction performance. This study suggests that the use of AFM nanoindentation can help to screen mechanical properties of pharmaceutical materials at early development stages of pharmaceutical research.

  1. Analysis of Hard Thin Film Coating

    Science.gov (United States)

    Shen, Dashen

    1998-01-01

    MSFC is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using electron cyclotron resonance chemical vapor deposition (ECRCVD) to deposit hard thin film an stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

  2. Double hard scattering without double counting

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, Markus [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Gaunt, Jonathan R. [VU Univ. Amsterdam (Netherlands). NIKHEF Theory Group; Schoenwald, Kay [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2017-02-15

    Double parton scattering in proton-proton collisions includes kinematic regions in which two partons inside a proton originate from the perturbative splitting of a single parton. This leads to a double counting problem between single and double hard scattering. We present a solution to this problem, which allows for the definition of double parton distributions as operator matrix elements in a proton, and which can be used at higher orders in perturbation theory. We show how the evaluation of double hard scattering in this framework can provide a rough estimate for the size of the higher-order contributions to single hard scattering that are affected by double counting. In a numeric study, we identify situations in which these higher-order contributions must be explicitly calculated and included if one wants to attain an accuracy at which double hard scattering becomes relevant, and other situations where such contributions may be neglected.

  3. Hard X-ray Photoelectric Polarimeter

    Data.gov (United States)

    National Aeronautics and Space Administration — Our objective is to determine the gas mixtures and pressures that would enable a sensitive, hard X-ray polarimeter using existing flight components with the goal of...

  4. Methane in German hard coal mining

    International Nuclear Information System (INIS)

    Martens, P.N.; Den Drijver, J.

    1995-01-01

    Worldwide, hard coal mining is being carried out at ever increasing depth, and has, therefore, to cope with correspondingly increasing methane emissions are caused by coal mining. Beside carbon dioxide, chloro-fluoro-carbons (CFCs) and nitrogen oxides, methane is one of the most significant 'greenhouse' gases. It is mainly through the release of such trace gases that the greenhouse effect is brought about. Reducing methane emissions is therefore an important problem to be solved by the coal mining industry. This paper begins by highlighting some of the fundamental principles of methane in hard coal mining. The methane problem in German hard coal mining and the industry's efforts to reduce methane emissions are presented. The future development in German hard coal mining is illustrated by an example which shows how large methane volumes can be managed, while still maintaining high outputs at increasing depth. (author). 7 tabs., 10 figs., 20 refs

  5. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... it free Find out why Close Why Are Drugs So Hard to Quit? National Institute on Drug Abuse (NIDA/NIH) Loading... Unsubscribe from National Institute on Drug Abuse (NIDA/NIH)? Cancel Unsubscribe Working... Subscribe Subscribed ...

  6. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... YouTube Red. Working... Not now Try it free Find out why Close Why Are Drugs So Hard ... hotline to help you or a loved one find treatment. For more information, visit http://www.easyread. ...

  7. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... So Hard to Quit? National Institute on Drug Abuse (NIDA/NIH) Loading... Unsubscribe from National Institute on Drug Abuse (NIDA/NIH)? Cancel Unsubscribe Working... Subscribe Subscribed Unsubscribe ...

  8. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... Feb 7, 2012 Quitting drugs is hard because addiction is a brain disease. Your brain is like ... out signals to direct your actions and choices. Addiction changes the signals in your brain and makes ...

  9. Why Are Drugs So Hard to Quit?

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    Full Text Available ... Drugs So Hard to Quit? National Institute on Drug Abuse (NIDA/NIH) Loading... Unsubscribe from National Institute on Drug Abuse (NIDA/NIH)? Cancel Unsubscribe Working... Subscribe Subscribed Unsubscribe ...

  10. Why Are Drugs So Hard to Quit?

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    Full Text Available ... in your brain and makes it hard to feel OK without the drug. This video from NIDA ... Advertise Developers +YouTube Terms Privacy Policy & Safety Send feedback Test new features Loading... Working... Sign in to ...

  11. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... has been rented. This feature is not available right now. Please try again later. Published on Feb 7, 2012 Quitting drugs is hard because addiction is a brain disease. Your brain is like a control tower ...

  12. A theoretical overview on single hard diffraction

    International Nuclear Information System (INIS)

    Wuesthoff, M.

    1996-01-01

    The concept of the Pomeron structure function and its application in Single Hard Diffraction at hadron colliders and in diffractive Deep Inelastic Scattering is critically reviewed. Some alternative approaches are briefly surveyed with a focus on QCD inspired models

  13. Double hard scattering without double counting

    International Nuclear Information System (INIS)

    Diehl, Markus; Gaunt, Jonathan R.

    2017-02-01

    Double parton scattering in proton-proton collisions includes kinematic regions in which two partons inside a proton originate from the perturbative splitting of a single parton. This leads to a double counting problem between single and double hard scattering. We present a solution to this problem, which allows for the definition of double parton distributions as operator matrix elements in a proton, and which can be used at higher orders in perturbation theory. We show how the evaluation of double hard scattering in this framework can provide a rough estimate for the size of the higher-order contributions to single hard scattering that are affected by double counting. In a numeric study, we identify situations in which these higher-order contributions must be explicitly calculated and included if one wants to attain an accuracy at which double hard scattering becomes relevant, and other situations where such contributions may be neglected.

  14. Hard scattering and gauge/string duality

    International Nuclear Information System (INIS)

    Polchinski, Joseph; Strassler, Matthew J.

    2002-01-01

    We consider high-energy fixed-angle scattering of glueballs in confining gauge theories that have supergravity duals. Although the effective description is in terms of the scattering of strings, we find that the amplitudes are hard (power law). This is a consequence of the warped geometry of the dual theory, which has the effect that in an inertial frame the string process is never in the soft regime. At small angle we find hard and Regge behaviors in different kinematic regions

  15. Soft skills, hard skills, and individual innovativeness

    DEFF Research Database (Denmark)

    Hendarman, Achmad Fajar; Cantner, Uwe

    2018-01-01

    of Indonesian firms from different industries are used from an online survey on manager and worker perceptions related to individual innovation performance on the one hand and individual skills on the other hand. The results show that soft skills and hard skills are significantly and positively associated...... with individual level innovativeness. However, no complementarity (positive interaction effect) is found between soft skills and hard skills....

  16. Hard template synthesis of metal nanowires

    OpenAIRE

    Kawamura, Go; Muto, Hiroyuki; Matsuda, Atsunori

    2014-01-01

    Metal nanowires (NWs) have attracted much attention because of their high electron conductivity, optical transmittance, and tunable magnetic properties. Metal NWs have been synthesized using soft templates such as surface stabilizing molecules and polymers, and hard templates such as anodic aluminum oxide, mesoporous oxide, carbon nanotubes. NWs prepared from hard templates are composites of metals and the oxide/carbon matrix. Thus, selecting appropriate elements can simplify the production o...

  17. Radiation-Hard Quartz Cerenkov Calorimeters

    International Nuclear Information System (INIS)

    Akgun, U.; Onel, Y.

    2006-01-01

    New generation hadron colliders are going to reach unprecedented energies and radiation levels. Quartz has been identified as a radiation-hard material that can be used for Cerenkov calorimeters of the future experiments. We report from the radiation hardness tests performed on quartz fibers, as well as the characteristics of the quartz fiber and plate Cerenkov calorimeters that have been built, designed, and proposed for the CMS experiment

  18. Radiation hard memory cell and array thereof

    International Nuclear Information System (INIS)

    Gunckel, T.L. II; Rovell, A.; Nielsen, R.L.

    1978-01-01

    A memory cell configuration that is implemented to be relatively hard to the adverse effects of a nuclear event is discussed. The presently disclosed memory cell can be interconnected with other like memory cells to form a high speed radiation hard register file. Information is selectively written into and read out of a memory cell comprising the register file, which memory cell preserves previously stored data without alteration in the event of exposure to high levels of nuclear radiation

  19. Standard test methods for rockwell hardness of metallic materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 These test methods cover the determination of the Rockwell hardness and the Rockwell superficial hardness of metallic materials by the Rockwell indentation hardness principle. This standard provides the requirements for Rockwell hardness machines and the procedures for performing Rockwell hardness tests. 1.2 This standard includes additional requirements in annexes: Verification of Rockwell Hardness Testing Machines Annex A1 Rockwell Hardness Standardizing Machines Annex A2 Standardization of Rockwell Indenters Annex A3 Standardization of Rockwell Hardness Test Blocks Annex A4 Guidelines for Determining the Minimum Thickness of a Test Piece Annex A5 Hardness Value Corrections When Testing on Convex Cylindrical Surfaces Annex A6 1.3 This standard includes nonmandatory information in appendixes which relates to the Rockwell hardness test. List of ASTM Standards Giving Hardness Values Corresponding to Tensile Strength Appendix X1 Examples of Procedures for Determining Rockwell Hardness Uncertainty Appendix X...

  20. Standard test methods for rockwell hardness of metallic materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 These test methods cover the determination of the Rockwell hardness and the Rockwell superficial hardness of metallic materials by the Rockwell indentation hardness principle. This standard provides the requirements for Rockwell hardness machines and the procedures for performing Rockwell hardness tests. 1.2 This standard includes additional requirements in annexes: Verification of Rockwell Hardness Testing Machines Annex A1 Rockwell Hardness Standardizing Machines Annex A2 Standardization of Rockwell Indenters Annex A3 Standardization of Rockwell Hardness Test Blocks Annex A4 Guidelines for Determining the Minimum Thickness of a Test Piece Annex A5 Hardness Value Corrections When Testing on Convex Cylindrical Surfaces Annex A6 1.3 This standard includes nonmandatory information in appendixes which relates to the Rockwell hardness test. List of ASTM Standards Giving Hardness Values Corresponding to Tensile Strength Appendix X1 Examples of Procedures for Determining Rockwell Hardness Uncertainty Appendix X...

  1. Novel hard compositions and methods of preparation

    Science.gov (United States)

    Sheinberg, H.

    1983-08-23

    Novel very hard compositions of matter are prepared by using in all embodiments only a minor amount of a particular carbide (or materials which can form the carbide in situ when subjected to heat and pressure); and no strategic cobalt is needed. Under a particular range of conditions, densified compositions of matter of the invention are prepared having hardnesses on the Rockwell A test substantially equal to the hardness of pure tungsten carbide and to two of the hardest commercial cobalt-bonded tungsten carbides. Alternately, other compositions of the invention which have slightly lower hardnesses than those described above in one embodiment also possess the advantage of requiring no tungsten and in another embodiment possess the advantage of having a good fracture toughness value. Photomicrographs show that the shapes of the grains of the alloy mixture with which the minor amount of carbide (or carbide-formers) is mixed are radically altered from large, rounded to small, very angular by the addition of the carbide. Superiority of one of these hard compositions of matter over cobalt-bonded tungsten carbide for ultra-high pressure anvil applications was demonstrated. 3 figs.

  2. Modification of bentonite clay and application on polypropylene nano composites

    International Nuclear Information System (INIS)

    Oliveira, Akidauana D.B.; Rodrigues, Andre W.B.; Agrawal, Pankaj; Araujo, Edcleide M.; Melo, Tomas J.A.

    2009-01-01

    This work consisted on the modification of Brasgel PA clay with ionic surfactant Praepagen WB and its incorporation into polypropylene. The results of infrared and DR-X was showed that the intercalation of surfactant in the clay and the incorporation of organoclay in PP matrix resulted in the formation of an intercalated structure. The impact strength of PP increased with the incorporation of organoclay. (author)

  3. Fast Reacting Nano Composite Energetic Materials: Synthesis and Combustion Characterization

    Science.gov (United States)

    2015-08-24

    nanoenergetic composites finding extensive use in ordnance and industrial applications, because of its high heat of combustion (~32 kJ/g) (S. H. Fischer ...2011. Farley, Cory. "Reactions of Aluminum with Halogen Containing Oxides." Dissertation. Lubbock, TX, May 2013. Gesner, Jeff , Michelle Pantoya, and...characteristics of novel hybrid nanoenergetic formulations." Combustion and Flame 158 (2011): 964- 978. S. H. Fischer , M. C. Grubelich. "Theoretical

  4. Fullerene and dendrimer based nano-composite gas separation membranes

    NARCIS (Netherlands)

    Sterescu, D.M.

    2007-01-01

    This thesis describes the development of new materials for membrane based gas separation processes. Long-term stable, loosely packed (high free volume) amorphous polymer films were prepared by introduction of super-molecular pendant groups, which possess hardsphere properties to avoid dense

  5. Ecoefficiency indicators for development of nano-composites

    DEFF Research Database (Denmark)

    Olsen, Stig Irving; Laurent, Alexis

    nanocomposites (5 wt%-nanofiller) were investigated; PU/CNT (in-situ polymerization), PP/CNT (in-situ polymerization), PU/clay (bulk polymerization), and PP/clay nanocomposites (bulk polymerization). Due to of lack of information, only the material stages (extraction of materials) and the production...

  6. Novel Nano composite Optical Plastics: Dispersion of Titanium in Polyacrylates

    International Nuclear Information System (INIS)

    Suri, G.; Tyagi, M.; Seshadri, G.; Khandal, R.K.; Verma, G.L.

    2010-01-01

    Polyacrylates have become the preferred materials for optical applications replacing the conventionally used glass due to their superior optical clarity. The major disadvantage with polyacrylates is their low (1.40-1.50) refractive index besides their poor impact resistance. The improvements in refractive index as well as mechanical properties can be achieved by way of incorporation of metals or metal compounds in the matrix. A novel methodology for the incorporation of high refractive index metals into low refractive index polymeric materials to improve the refractive index and impact resistance of the latter has been developed. With the in-situ formation of nanoparticles of TiO 2 , the refractive index of polyacrylates improved from 1.45 to 1.53 and the Abbe number increased from 40 to 57. One of the interesting dimension of this study pertains to the possibility of tailor-making of the two key optical properties of materials by way of varying the amount of TiO 2 being formed in-situ. Thermal stability and impact resistance of nano dispersed (4.3% by wt. of Ti) polyacrylates are found to be better than the neat polyacrylates. Moreover, TiO 2 -containing polyacrylate is of light weight. TEM, SEM, and IR analysis confirms the in-situ formation of nanoparticles of TiO 2 . Gamma irradiation has been used as an eco-friendly technique for polymerization. The developed compositions can be cast polymerized into clear and bubble free material for optical applications.

  7. Multifunctional polymer nano-composite based superhydrophobic surface

    Science.gov (United States)

    Maitra, Tanmoy; Asthana, Ashish; Buchel, Robert; Tiwari, Manish K.; Poulikakos, Dimos

    2014-11-01

    Superhydrophobic surfaces become desirable in plethora of applications in engineering fields, automobile industry, construction industries to name a few. Typical fabrication of superhydrophobic surface consists of two steps: first is to create rough morphology on the substrate of interest, followed by coating of low energy molecules. However, typical exception of the above fabrication technique would be direct coating of functional polymer nanocomposites on substrate where superhydrophobicity is needed. Also in this case, the use of different nanoparticles in the polymer matrix can be exploited to impart multi-functional properties to the superhydrophobic coatings. Herein, different carbon nanoparticles like graphene nanoplatelets (GNP), carbon nanotubes (CNT) and carbon black (CB) are used in fluropolymer matrix to prepare superhydrophobic coatings. The multi-functional properties of coatings are enhanced by combining two different carbon fillers in the matrix. The aforementioned superhydrophobic coatings have shown high electrical conductivity and excellent droplet meniscus impalement resistance. Simultaneous superhydrophobic and oleophillic character of the above coating is used to separate mineral oil and water through filtration of their mixture. Swiss National Science Foundation (SNF) Grant 200021_135479.

  8. NanoComposite Polymers for High Resolution Near Infrared Detectors

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop nanocomposite materials with tuned refractive index in the near infra red spectral range as an index-matched immersion lens for high resolution infra-red...

  9. Advanced Nano-Composites for Increased Energy Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-05-01

    This factsheet describes a research project whose goal is to increase energy efficiency and operating lifetime of wear-intensive industrial components and systems by developing and commercializing a family of ceramic-based monolithic composites that have shown remarkable resistance to wear in laboratory tests.

  10. Polypropylene Nano-composites at High Strain Rate Impacts ...

    African Journals Online (AJOL)

    KBHEEMA

    2017-12-25

    Dec 25, 2017 ... ... requires appropriate selection of performance properties of different ... For example, (Shariatpanahi et al., 2009) revealed improvements of 15% and .... What is important to note is that the directional trend of data points to ...

  11. Carbon Nano-Composite Ablative Rocket Nozzles, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The constantly evolving science of nanotechnology keeps coming around to old ideas re-tooled with new technologies. Though much work has been done examining the...

  12. Structure, production and properties of high-melting compounds and systems (hard materials and hard metals)

    International Nuclear Information System (INIS)

    Holleck, H.; Thuemmler, F.

    1979-07-01

    The report contains contributions by various authors to the research project on the production, structure, and physical properties of high-melting compounds and systems (hard metals and hard materials), in particular WC-, TaC-, and MoC-base materials. (GSCH) [de

  13. Analytical Modeling of Hard-Coating Cantilever Composite Plate considering the Material Nonlinearity of Hard Coating

    Directory of Open Access Journals (Sweden)

    Wei Sun

    2015-01-01

    Full Text Available Due to the material nonlinearity of hard coating, the coated structure produces the nonlinear dynamical behaviors of variable stiffness and damping, which make the modeling of hard-coating composite structure become a challenging task. In this study, the polynomial was adopted to characterize this material nonlinearity and an analytical modeling method was developed for the hard-coating composite plate. Firstly, to relate the hard-coating material parameters obtained by test and the analytical model, the expression of equivalent strain of composite plate was derived. Then, the analytical model of hard-coating composite plate was created by energy method considering the material nonlinearity of hard coating. Next, using the Newton-Raphson method to solve the vibration response and resonant frequencies of composite plate and a specific calculation procedure was also proposed. Finally, a cantilever plate coated with MgO + Al2O3 hard coating was chosen as study case; the vibration response and resonant frequencies of composite plate were calculated using the proposed method. The calculation results were compared with the experiment and general linear calculation, and the correctness of the created model was verified. The study shows the proposed method can still maintain an acceptable precision when the material nonlinearity of hard coating is stronger.

  14. Erosion testing of hard materials and coatings

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, Jeffrey A.

    2005-04-29

    Erosion is the process by which unconstrained particles, usually hard, impact a surface, creating damage that leads to material removal and component failure. These particles are usually very small and entrained in fluid of some type, typically air. The damage that occurs as a result of erosion depends on the size of the particles, their physical characteristics, the velocity of the particle/fluid stream, and their angle of impact on the surface of interest. This talk will discuss the basics of jet erosion testing of hard materials, composites and coatings. The standard test methods will be discussed as well as alternative approaches to determining the erosion rate of materials. The damage that occurs will be characterized in genera1 terms, and examples will be presented for the erosion behavior of hard materials and coatings (both thick and thin).

  15. Aespoe Hard Rock Laboratory. Annual Report 1993

    International Nuclear Information System (INIS)

    1994-06-01

    The Aespoe Hard Rock Laboratory is being constructed in preparation for the deep geological repository of spent fuel in Sweden. This Annual Report 1993 for the Aespoe Hard Rock Laboratory contains an overview of the work conducted. Present work is focused on verification of pre-investigation methods and development of the detailed investigation methodology. Construction of the facility and investigation of the bedrock are carried out in parallel. As of December 1993, 2760 m of the tunnel had been excavated to a depth of 370 m below the surface. An important and integral part of the work is further refinement of conceptual and numerical models for groundwater flow and radionuclide migration. Detailed plans have been prepared for several experiments to be conducted after the end of the construction work. Eight organizations from seven countries are now participating in the work at the Aespoe Hard Rock Laboratory and are contributing in different ways to the results being achieved

  16. Hard template synthesis of metal nanowires

    Directory of Open Access Journals (Sweden)

    Go eKawamura

    2014-11-01

    Full Text Available Metal nanowires (NWs have attracted much attention because of their high electron conductivity, optical transmittance and tunable magnetic properties. Metal NWs have been synthesized using soft templates such as surface stabilizing molecules and polymers, and hard templates such as anodic aluminum oxide, mesoporous oxide, carbon nanotubes. NWs prepared from hard templates are composites of metals and the oxide/carbon matrix. Thus, selecting appropriate elements can simplify the production of composite devices. The resulting NWs are immobilized and spatially arranged, as dictated by the ordered porous structure of the template. This avoids the NWs from aggregating, which is common for NWs prepared with soft templates in solution. Herein, the hard template synthesis of metal NWs is reviewed, and the resulting structures, properties and potential applications are discussed.

  17. Hard template synthesis of metal nanowires

    Science.gov (United States)

    Kawamura, Go; Muto, Hiroyuki; Matsuda, Atsunori

    2014-11-01

    Metal nanowires (NWs) have attracted much attention because of their high electron conductivity, optical transmittance and tunable magnetic properties. Metal NWs have been synthesized using soft templates such as surface stabilizing molecules and polymers, and hard templates such as anodic aluminum oxide, mesoporous oxide, carbon nanotubes. NWs prepared from hard templates are composites of metals and the oxide/carbon matrix. Thus, selecting appropriate elements can simplify the production of composite devices. The resulting NWs are immobilized and spatially arranged, as dictated by the ordered porous structure of the template. This avoids the NWs from aggregating, which is common for NWs prepared with soft templates in solution. Herein, the hard template synthesis of metal NWs is reviewed, and the resulting structures, properties and potential applications are discussed.

  18. Liquid agents for dispersion of hard alloys

    International Nuclear Information System (INIS)

    Putintseva, M.N.

    2006-01-01

    Effects of dispersant properties on granulometric, chemical, and phase composition of the products of WC hard alloy electroerosion are considered. It is established that an increase of liquid dispersant permittivity results in enhanced powder dispersity, and an increase of boiling temperature and kinematic viscosity of a hydrocarbon liquid promotes a carbon loss from WC and intensifies pyrolysis of the liquid.On electroerosion of WC base hard alloy in oil a powder particle consists of b-WC+W 2 C phases, in kerosine - of a-WC+b-WC, in distilled water - of W+W 2 C. The viscosity of liquid dispersants practically has no effect on powder particle size [ru

  19. Induction surface hardening of hard coated steels

    DEFF Research Database (Denmark)

    Pantleon, Karen; Kessler, Olaf; Hoffmann, Franz

    1999-01-01

    The deposition of hard coatings with CVD-processes is commonly used to improve the wear resistance e.g. of tool steels in forming. The advantages of CVD are undisputed (high deposition rates with simple equipment, excellent coating properties). Nevertheless, the disadvantage of the CVD-process is......The deposition of hard coatings with CVD-processes is commonly used to improve the wear resistance e.g. of tool steels in forming. The advantages of CVD are undisputed (high deposition rates with simple equipment, excellent coating properties). Nevertheless, the disadvantage of the CVD...

  20. Rad Hard Active Media For Calorimeters

    CERN Document Server

    Norbeck, E; Möller, A; Onel, Y

    2006-01-01

    Zero-degree calorimeters have limited space and extreme levels of radiation. A simple, low cost, radiation hard design uses tungstenmetal as the absorber and a suitable liquid as the ˇCerenkov radiator. In other applications a PPAC (Parallel Plate Avalanche Counter) operatingwith a suitable atmosphericpressure gas is an attractive active material for a calorimeter. It can be made radiation hard and has sufficient gain in the gas that no electronic components are needed near the detector. It works well even with the highest concentration of shower particles. For this pressure range, R134A (used in auto air conditioners) has many desirable features.

  1. Hardness of basaltic glass-ceramics

    DEFF Research Database (Denmark)

    Jensen, Martin; Smedskjær, Morten Mattrup; Estrup, Maja

    2009-01-01

    The dependence of the hardness of basaltic glass-ceramics on their degree of crystallisation has been explored by means of differential scanning calorimetry, optical microscopy, x-ray diffraction, and Vickers indentation. Different degrees of crystallisation in the basaltic glasses were achieved...... by varying the temperature of heat treatment. The predominant crystalline phase in the glass was identified as augite. It was found that the hardness of the glass phase decreased slightly with an increase in the degree of crystallisation, while that of the augite phase drastically decreased....

  2. Effects of explosions in hard rocks

    International Nuclear Information System (INIS)

    Heuze, F.E.; Walton, O.R.; Maddix, D.M.; Shaffer, R.J.; Butkovich, T.R.

    1993-01-01

    This work relates to explosions in hard rocks (ex: basalt, granite, limestone...). Hard rock masses typically have a blocky structure created by the existence of geologic discontinuities such as bedding contacts, faults, and joints. At very high pressure - hundreds of kilobars and above - these discontinuities do not act separately, and the rock appears to be an equivalent continuous medium. At stress of a few tens of kilobars and below, the geologic discontinuities control the kinematics of the rock masses. Hence, the simulation of rock dynamics, anywhere but in the very-near source region, should account for those kinematics

  3. Novel Aspects of Hard Diffraction in QCD

    International Nuclear Information System (INIS)

    Brodsky, Stanley J.

    2005-01-01

    Initial- and final-state interactions from gluon-exchange, normally neglected in the parton model have a profound effect in QCD hard-scattering reactions, leading to leading-twist single-spin asymmetries, diffractive deep inelastic scattering, diffractive hard hadronic reactions, and nuclear shadowing and antishadowing--leading-twist physics not incorporated in the light-front wavefunctions of the target computed in isolation. I also discuss the use of diffraction to materialize the Fock states of a hadronic projectile and test QCD color transparency

  4. Radiation hardness of undoped BGO crystals

    International Nuclear Information System (INIS)

    Sahu, S.K.; Peng, K.C.; Huang, H.C.; Wang, C.H.; Chang, Y.H.; Hou, W.S.; Ueno, K.; Chou, F.I.; Wei, Y.Y.

    1997-01-01

    We measured the radiation hardness of undoped BGO crystals from two different manufacturers. Such crystals are proposed to be used in a small-angle calorimeter of the BELLE detector of the KEK B-factory. Transparency and scintillation light output of the crystals were monitored to see the effect of radiation damage. The crystals show considerable radiation hardness up to 10.2 Mrad equivalent dose, which is much higher than the maximum expected dosage of 500 krad per year of running at BELLE. (orig.)

  5. Hardness of carbides, nitrides, and borides

    International Nuclear Information System (INIS)

    Schroeter, W.

    1981-01-01

    Intermetallic compounds of metals with non-metals such as C, N, and B show different hardness. Wagner's interaction parameter characterizes manner and extent of the interaction between the atoms of the substance dissolved and the additional elements in metallic mixed phases. An attempt has been made to correlate the hardness of carbides, nitrides, and borides (data taken from literature) with certain interaction parameters and associated thermodynamic quantities (ΔH, ΔG). For some metals of periods 4, 5, and 6 corresponding relations were found between microhardness, interaction parameters, heat of formation, and atomic number

  6. Diffusion corrections to the hard pomeron

    CERN Document Server

    Ciafaloni, Marcello; Müller, A H; Ciafaloni, Marcello; Taiuti, Martina

    2001-01-01

    The high-energy behaviour of two-scale hard processes is investigated in the framework of small-x models with running coupling, having the Airy diffusion model as prototype. We show that, in some intermediate high-energy regime, the perturbative hard Pomeron exponent determines the energy dependence, and we prove that diffusion corrections have the form hinted at before in particular cases. We also discuss the breakdown of such regime at very large energies, and the onset of the non-perturbative Pomeron behaviour.

  7. Analysis of the development and performance of hard disks

    OpenAIRE

    Novak, Davorin

    2010-01-01

    With the emergence of new technologies in the field of hard drives we can witness a significant increase of surface density and transfer rate of interfaces which, as a result, enables greater performance and reliability of hard disks. The reason for this are increasing needs for higher capacities and data transfer rate to or from the hard disk. This thesis presents the structure of hard drives, features, performance and reliability of hard drives and alternative data storage technologies. Par...

  8. Possible connections between hard and soft processes

    International Nuclear Information System (INIS)

    Blankenbecler, R.

    1977-10-01

    Three topics in constituent hadron models are reviewed: the connection between fixed angle and Regge behavior, the validity of the hard scattering expansion and restrictions on the effects of the transverse momentum of constituents, and the x distribution in the fragmentation region at low transverse momentum. 6 figures

  9. Parallel Narrative Structure in Paul Harding's "Tinkers"

    Science.gov (United States)

    Çirakli, Mustafa Zeki

    2014-01-01

    The present paper explores the implications of parallel narrative structure in Paul Harding's "Tinkers" (2009). Besides primarily recounting the two sets of parallel narratives, "Tinkers" also comprises of seemingly unrelated fragments such as excerpts from clock repair manuals and diaries. The main stories, however, told…

  10. Registration of 'Prevail' hard red spring wheat

    Science.gov (United States)

    Grower and end-user acceptance of new Hard Red Spring Wheat (HRSW; Triticum aestivum L.) cultivars is largely contingent upon satisfactory agronomic performance, end-use quality potential, and disease resistance levels. Additional characteristics, such as desirable plant height, can also contribute...

  11. Hard x-ray telescope mission

    DEFF Research Database (Denmark)

    Gorenstein, P.; Worrall, D.; Joensen, K.D.

    1996-01-01

    The Hard X-Ray Telescope was selected for study as a possible new intermediate size mission for the early 21st century. Its principal attributes are: (1) multiwavelength observing with a system of focussing telescopes that collectively observe from the UV to over 1 MeV, (2) much higher sensitivity...

  12. Systematic hardness studies on lithium niobate crystals

    Indian Academy of Sciences (India)

    Unknown

    crystals with different growth origins, and a Fe-doped sample. The problem of load ... The true hardness of LiNbO3 is found to be 630 ± 30 kg/mm2. .... Experimental. Pure lithium ... the index of d strikes at this simple and meaningful defini-.

  13. "Work smart, wear your hard hat"

    CERN Multimedia

    2003-01-01

    Falling objects and collisions are frequent occurrences in work sites and hazardous areas. Hard hats can help prevent many types of accident and can even save lives. Just imagine an 800 g spanner falling from a 13 m high scaffold onto the head of someone standing below - a nightmare scenario! The impact to the head is equivalent to that of a 5 kg weight falling from 2 metres. That is just what happened to Gerd Fetchenhauer when he was working on the UA1 experiment. Fortunately, he was wearing a hard hat at the time. "That hat saved my life," he explains. "It punched a hole right through the hat and I was a bit dazed for a couple of hours but otherwise I was OK." Since that day, Gerd Fetchenhauer, now working on CMS, is never seen on a work site without his hard hat on. Work sites have proliferated at CERN with the construction of the LHC and its detectors, and the wearing of hard hats is compulsory (not to mention life-saving). In the underground caverns and experiment halls, where gantry cranes and other h...

  14. Cobalt allergy in hard metal workers

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, T; Rystedt, I

    1983-03-01

    Hard metal contains about 10% cobalt. 853 hard metal workers were examined and patch tested with substances from their environment. Initial patch tests with 1% cobalt chloride showed 62 positive reactions. By means of secondary serial dilution tests, allergic reactions to cobalt were reproduced in 9 men and 30 women. Weak reactions could not normally be reproduced. A history of hand eczema was found in 36 of the 39 individuals with reproducible positive test reactions to cobalt, while 21 of 23 with a positive initial patch test but negative serial dilution test had never had any skin problems. Hand etching and hand grinding, mainly female activities and traumatic to the hands, were found to involve the greatest risk of cobalt sensitization. 24 individuals had an isolated cobalt allergy. They had probably been sensitized by hard metal work, while the individuals, all women, who had simultaneous nickel allergy had probably been sensitized to nickel before their employment and then became sensitized to cobalt by hard metal work. A traumatic occupation, which causes irritant contact dermatitis and/or a previous contact allergy or atopy is probably a prerequisite for the development of cobalt allergy.

  15. Sustaining Transformation: "Resiliency in Hard Times"

    Science.gov (United States)

    Guarasci, Richard; Lieberman, Devorah

    2009-01-01

    The strategic, systemic, and encompassing evolution of a college or university spans a number of years, and the vagaries of economic cycles inevitably catch transforming institutions in mid-voyage. "Sustaining Transformation: Resiliency in Hard Times" presents a study of Wagner College as it moves into its second decade of purposeful…

  16. Induction surface hardening of hard coated steels

    Energy Technology Data Exchange (ETDEWEB)

    Pantleon, K.; Kessler, O.; Hoffann, F.; Mayr, P. [Stiftung Inst. fuer Werkstofftechnik, Bremen (Germany)

    1999-11-01

    The properties of hard coatings deposited using CVD processes are usually excellent. However, high deposition temperatures negatively influence the substrate properties, especially in the case of low alloyed steels. Therefore, a subsequent heat treatment is necessary to restore the properties of steel substrates. Here, induction surface hardening is used as a method of heat treatment after the deposition of TiN hard coatings on AISI 4140 (DIN42CrMo4) substrates. The influences of the heat treatment on both the coating and the substrate properties are discussed in relation to the parameters of induction heating. Thereby, the heating time, heating atmosphere and the power input into the coating-substrate compounds are varied. As a result of induction surface hardening, the properties of the substrates are improved without losing good coating properties. High hardness values in the substrate near the interface allow the AISI 4140 substrates to support TiN hard coatings very well. Consequently, higher critical loads are measured in scratch tests after the heat treatment. Also, compressive residual stresses in the substrate are generated. In addition, only a very low distortion appears. (orig.)

  17. Hard scattering in γp interactions

    International Nuclear Information System (INIS)

    Ahmed, T.; Andreev, V.; Andrieu, B.

    1992-10-01

    We report on the investigation of the final state in interactions of quasi-real photons with protons. The data were taken with the H1 detector at the HERA ep collider. Evidence for hard interactions is seen in both single particle spectra and jet formation. The data can best be described by inclusion of resolved photon processes as predicted by QCD. (orig.)

  18. Soft gluon contributions to hard processes

    International Nuclear Information System (INIS)

    Ciafaloni, M.

    1981-10-01

    The main concern of this paper is in trying to elucidate the origin of large QCD perturbative corrections and explain how to deal with them to all orders. They come essentially from the phase space regions close to the kinematical boundary of a hard process, in which one or many gluons become soft

  19. Hard Pseudocompact Spaces | Ghosh | Quaestiones Mathematicae

    African Journals Online (AJOL)

    ... which was absent in the literature. Finally, under smallness restrictions on hyper-real remainder of the Stone Cech compactification of a Tychonoff space we have achieved in producing a representation for hard pseudocompact space. Keywords: Compactification, Hewitt realcompactification, pseudocompact, realcompact

  20. Diffractive hard scattering and the SSC

    International Nuclear Information System (INIS)

    Berger, E.L.; Collins, J.C.; Soper, D.E.; Sterman, G.

    1986-01-01

    Events in high energy hadron collisions are discussed that contain a hard scattering, in the sense that very heavy quarks or high P/sub T/ jets are produced, yet are diffractive, in the sense that one of the incident hadrons is scattered with only a small energy loss. 12 refs., 6 figs

  1. Effect of gum hardness on chewing pattern.

    Science.gov (United States)

    Plesh, O; Bishop, B; McCall, W

    1986-06-01

    Chewing rhythms are set by a putative central pattern generator whose output is influenced by sensory feedback. In this study we assessed how an altered feedback imposed by changing the hardness of a gum bolus modifies the timing of chewing, the maximal gape, and the activity in the masseter muscle on the chewing side. Ten adult subjects with no orofacial dysfunction chewed a standard piece of soft or hard gum for at least 3 min in random order. Vertical jaw movements were recorded with a kinesiograph and activity of the masseter muscle was recorded and integrated from surface EMG electrodes. The subjects sat in a dental chair and viewed a video lecture to distract their attention from chewing; they were instructed to chew on the right molars. Cycle-by-cycle analysis showed that 9 of the 10 subjects chewed the hard gum more slowly than the soft with no significant change in gape. The increases in cycle duration were due to changes in the duration of the opening and occlusal phases. The duration of closing was not significantly changed even though the duration and level of masseter activity were both significantly increased. We conclude that gum hardness by altering proprioceptive feedback modifies the output of the masticatory central pattern generator in such a way that the temporal aspects of chewing and the output of the masseteric motor pool are affected.

  2. Decision-theoretic troubleshooting: Hardness of approximation

    Czech Academy of Sciences Publication Activity Database

    Lín, Václav

    2014-01-01

    Roč. 55, č. 4 (2014), s. 977-988 ISSN 0888-613X R&D Projects: GA ČR GA13-20012S Institutional support: RVO:67985556 Keywords : Decision-theoretic troubleshooting * Hardness of approximation * NP-completeness Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 2.451, year: 2014

  3. Remember Hard but Think Softly: Metaphorical Effects of Hardness/Softness on Cognitive Functions

    Directory of Open Access Journals (Sweden)

    Jiushu Xie

    2016-09-01

    Full Text Available Previous studies have found that bodily stimulation, such as hardness, biases social judgment and evaluation via metaphorical association; however, it remains unclear whether bodily stimulation also affects cognitive functions, such as memory and creativity. The current study used metaphorical associations between hard and rigid and between soft and flexible in Chinese, to investigate whether the experience of hardness affected cognitive functions requiring either rigidity (memory or flexibility (creativity. In Experiment 1, we found that Chinese-speaking participants performed better at recalling previously memorized words while sitting on a hard-surface stool (the hard condition than a cushioned one (the soft condition. In Experiment 2, participants sitting on a cushioned stool outperformed those sitting on a hard-surface stool on a Chinese riddle task, which required creative/flexible thinking, but not on an analogical reasoning task, which required both rigid and flexible thinking. The results suggest the hardness experience affects cognitive functions that are metaphorically associated with rigidity and flexibility. They support the embodiment proposition that cognitive functions and representations could be grounded via metaphorical association in bodily states.

  4. Hard Distraction and Deep Inelastic Scattering

    International Nuclear Information System (INIS)

    BJORKEN, J.D.

    1994-01-01

    Since the advent of hard-collision physics, the study of diffractive processes- 'shadow physics' - has been less prominent than before. However, there is now a renewed interest in the subject, especially in that aspect which synthesizes the short-distance, hard-collision phenomena with the classical physics of large rapidity-gaps. This is especially stimulated by the recent data on deep-inelastic scattering from HERA, as well as the theoretical work which relates to it. The word 'diffraction' is sometimes used by high-energy physicists in a loose way. So I here begin by defining what I mean by the term: A diffractive process occurs if and only if there is a large rapidity gap in the produced-particle phase space which is not exponentially suppressed. Here a rapidity gap means essentially no hadrons produced into the rapidity gap (which operates in the 'lego' phase-space of pseudo-rapidity and azimuthal angle). And non-exponential suppression implies that the cross-section for creating a gap with width Δη does not have a power-law decrease with increasing sub energy Δη, but behaves at most like some power of pseudorapidity Δη∼ logs. The term 'hard diffraction' shall simply refer to those diffractive processes which have jets in the final-state phase-space. We may also distinguish, if desired, two subclasses, as suggested by Ingelman i) Diffractive hard processes have jets on only one side of the rapidity gap. ii) Hard diffractive processes have jets on both sides of the rapidity gap

  5. Thermodynamic perturbation theory for fused hard-sphere and hard-disk chain fluids

    International Nuclear Information System (INIS)

    Zhou, Y.; Hall, C.K.; Stell, G.

    1995-01-01

    We find that first-order thermodynamic perturbation theory (TPT1) which incorporates the reference monomer fluid used in the generalized Flory--AB (GF--AB) theory yields an equation of state for fused hard-sphere (FHS) chain fluids that has accuracy comparable to the GF--AB and GF--dimer--AC theories. The new TPT1 equation of state is significantly more accurate than other extensions of the TPT1 theory to FHS chain fluids. The TPT1 is also extended to two-dimensional fused hard-disk chain fluids. For the fused hard-disk dimer fluid, the extended TPT1 equation of state is found to be more accurate than the Boublik hard-disk dimer equation of state. copyright 1995 American Institute of Physics

  6. Hard diffraction and small-x

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    In the United States, phrases such as ''small-x evolution'', ''the BFKL Pomeron'', ''deep-inelastic rapiditygap events'' and ''hard-diffraction'' do not generate the same intensity of discussion amongst high-energy physicists that they do in Europe. However, for three days in the fall such discussion filled the air at Fermilab. The ''2nd Workshop on Small-x and Diffractive Physics at the Tevatron'' was a review of the rapid theoretical and experimental progress taking place in this field. Although Quantum Chromo-dynamics (QCD) has been established as the theory of strong interactions for twenty years, as yet neither perturbative high-energy calculations nor low-energy non-perturbative techniques have been successfully extended to the mixture of high energy and low transverse momenta which characterize traditional ''soft'' diffractive processes. The simplest soft diffractive process is elastic scattering. In this case it is easiest to accept that there is an exchanged ''pomeron'', which can be pictured as a virtual entity with no electric charge or strong charge (colour), perhaps like an excitation of the vacuum. The same pomeron is expected to appear in all diffractive processes. Understanding the pomeron in QCD is a fundamental theoretical and experimental challenge. In the last two or three years the ''frontier'' in this challenging area of QCD has been pushed back significantly in both theory and experiment. Progress has been achieved by studying the evolution of hard collisions to relatively smaller constituent momenta (small x) and by studying ''hard'' diffractive collisions containing simultaneous signatures of diffraction and hard perturbative processes. The hard processes have included high transverse momentum jet production, deep inelastic lepton scattering, and (most recently) W

  7. Microbiological quality of soft, semi-hard and hard cheeses during the shelf-life

    Directory of Open Access Journals (Sweden)

    Josip Vrdoljak

    2016-03-01

    Full Text Available Cheeses as ready-to-eat food should be considered as a potential source of foodborne pathogens, primarily Listeria monocytogenes. The aim of present study was to determine the microbiological quality of soft, semi-hard and hard cheeses during the shelf-life, with particular reference to L. monocytogenes. Five types of cheeses were sampled at different timepoints during the cold storage and analyzed for presence of Salmonella and L. monocytogenes, as well as lactic acid bacteria, Escherichia coli, coagulase-positive staphylococci, yeasts, molds, sulfite-reducing clostridia and L. monocytogenes counts. Water activity, pH and NaCl content were monitored in order to evaluate the possibility of L. monocytogenes growth. Challenge test for L. monocytogenes was performed in soft whey cheese, to determine the growth potential of pathogen during the shelf-life of product. All analyzed cheeses were compliant with microbiological criteria during the shelf-life. In soft cheeses, lactic acid bacteria increased in the course of the shelf-life period (1.2-2.6 log increase, while in semi-hard and hard cheeses it decreased (1.6 and 5.2 log decrease, respectively. Soft cheeses support the growth of L. monocytogenes according to determined pH values (5.8-6.5, water activity (0.99-0.94, and NaCl content (0.3-1.2%. Challenge test showed that L. monocytogenes growth potential in selected soft cheese was 0.43 log10 cfu/g during 8 days at 4°C. Water activity in semi-hard and hard cheeses was a limiting factor for Listeria growth during the shelf-life. Soft, semi-hard and hard cheeses were microbiologically stable during their defined shelf-life. Good manufacturing and hygienic practices must be strictly followed in the production of soft cheeses as Listeria-supporting food and be focused on preventing (recontamination.

  8. Bond-orientational analysis of hard-disk and hard-sphere structures.

    Science.gov (United States)

    Senthil Kumar, V; Kumaran, V

    2006-05-28

    We report the bond-orientational analysis results for the thermodynamic, random, and homogeneously sheared inelastic structures of hard-disks and hard-spheres. The thermodynamic structures show a sharp rise in the order across the freezing transition. The random structures show the absence of crystallization. The homogeneously sheared structures get ordered at a packing fraction higher than the thermodynamic freezing packing fraction, due to the suppression of crystal nucleation. On shear ordering, strings of close-packed hard-disks in two dimensions and close-packed layers of hard-spheres in three dimensions, oriented along the velocity direction, slide past each other. Such a flow creates a considerable amount of fourfold order in two dimensions and body-centered-tetragonal (bct) structure in three dimensions. These transitions are the flow analogs of the martensitic transformations occurring in metals due to the stresses induced by a rapid quench. In hard-disk structures, using the bond-orientational analysis we show the presence of fourfold order. In sheared inelastic hard-sphere structures, even though the global bond-orientational analysis shows that the system is highly ordered, a third-order rotational invariant analysis shows that only about 40% of the spheres have face-centered-cubic (fcc) order, even in the dense and near-elastic limits, clearly indicating the coexistence of multiple crystalline orders. When layers of close-packed spheres slide past each other, in addition to the bct structure, the hexagonal-close-packed (hcp) structure is formed due to the random stacking faults. Using the Honeycutt-Andersen pair analysis and an analysis based on the 14-faceted polyhedra having six quadrilateral and eight hexagonal faces, we show the presence of bct and hcp signatures in shear ordered inelastic hard-spheres. Thus, our analysis shows that the dense sheared inelastic hard-spheres have a mixture of fcc, bct, and hcp structures.

  9. Remember Hard But Think Softly: Metaphorical Effects of Hardness/Softness on Cognitive Functions

    Science.gov (United States)

    Xie, Jiushu; Lu, Zhi; Wang, Ruiming; Cai, Zhenguang G.

    2016-01-01

    Previous studies have found that bodily stimulation, such as hardness biases social judgment and evaluation via metaphorical association; however, it remains unclear whether bodily stimulation also affects cognitive functions, such as memory and creativity. The current study used metaphorical associations between “hard” and “rigid” and between “soft” and “flexible” in Chinese, to investigate whether the experience of hardness affects cognitive functions whose performance depends prospectively on rigidity (memory) and flexibility (creativity). In Experiment 1, we found that Chinese-speaking participants performed better at recalling previously memorized words while sitting on a hard-surface stool (the hard condition) than a cushioned one (the soft condition). In Experiment 2, participants sitting on a cushioned stool outperformed those sitting on a hard-surface stool on a Chinese riddle task, which required creative/flexible thinking, but not on an analogical reasoning task, which required both rigid and flexible thinking. The results suggest the hardness experience affects cognitive functions that are metaphorically associated with rigidity or flexibility. They support the embodiment proposition that cognitive functions and representations can be grounded in bodily states via metaphorical associations. PMID:27672373

  10. Hard-on-hard lubrication in the artificial hip under dynamic loading conditions.

    Directory of Open Access Journals (Sweden)

    Robert Sonntag

    Full Text Available The tribological performance of an artificial hip joint has a particularly strong influence on its success. The principle causes for failure are adverse short- and long-term reactions to wear debris and high frictional torque in the case of poor lubrication that may cause loosening of the implant. Therefore, using experimental and theoretical approaches models have been developed to evaluate lubrication under standardized conditions. A steady-state numerical model has been extended with dynamic experimental data for hard-on-hard bearings used in total hip replacements to verify the tribological relevance of the ISO 14242-1 gait cycle in comparison to experimental data from the Orthoload database and instrumented gait analysis for three additional loading conditions: normal walking, climbing stairs and descending stairs. Ceramic-on-ceramic bearing partners show superior lubrication potential compared to hard-on-hard bearings that work with at least one articulating metal component. Lubrication regimes during the investigated activities are shown to strongly depend on the kinematics and loading conditions. The outcome from the ISO gait is not fully confirmed by the normal walking data and more challenging conditions show evidence of inferior lubrication. These findings may help to explain the differences between the in vitro predictions using the ISO gait cycle and the clinical outcome of some hard-on-hard bearings, e.g., using metal-on-metal.

  11. Developing very hard nanostructured bainitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Amel-Farzad, H., E-mail: hh_amel@yahoo.com [Department of Materials Engineering and Metallurgy, Faculty of Engineering, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of); Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Faridi, H.R., E-mail: faridihr@yahoo.com [Department of Materials Engineering and Metallurgy, Hamedan University of Technology, Hamedan (Iran, Islamic Republic of); Rajabpour, F.; Abolhasani, A.; Kazemi, Sh.; Khaledzadeh, Y. [Department of Materials Engineering and Metallurgy, Faculty of Engineering, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of)

    2013-01-01

    Novel nanostructured high carbon high silicon, carbide-free bainitic steels with very high strength and good ductility have been developed in the recent decade. In this work, an alloy with a high carbon content and no manganese was designed and cast. The prepared samples were heat treated through an austempering process in the range 200-350 Degree-Sign C. Optical and scanning electron microscopes and XRD were used to analyze the microstructures precisely. Bainitic ferrite plates of just a few tens of nanometer thickness were obtained with the hardness of 697{+-}6 HV. It is reasonable to say that the unprecedented hardness values obtained in this work are mostly caused by the extraordinary carbon content of the alloy.

  12. Nanoindentation hardness of banded Australian sedimentary opal

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, P S; Smallwood, A S; Ray, A S [Department of Chemistry, Material and Forensic Science, University of Technology Sydney, PO Box 123, Broadway, NSW 2007 (Australia); Briscoe, B J; Parsonage, D [Department of Chemical Engineering and Chemical Technology, Imperial College of Science, Technology and Medicine, London, SW7 2AZ (United Kingdom)], E-mail: paul.thomas@uts.edu.au

    2008-04-07

    Nanoindentation hardness data in continuous stiffness mode are reported for banded potch and play of colour opals sourced from Lightning Ridge in New South Wales and Andamooka in South Australia. Despite the significant visible heterogeneities observed and the significant differences in origin and microstructures, as observed by SEM, and subtle differences in the elemental distributions between bands within specimens, little difference was observed in the mechanical properties. Specimens were found to be mechanically homogeneous and values of the hardness and moduli were found to be similar between samples. The creep behaviour of the specimens was also observed to be similar. It was concluded that the similarities in mechanical properties were due to the similarities in the silica morphology of the specimens, formed in similar geological environments, as differences in microstructure and trace element distribution were found not to significantly influence the observed bulk mechanical properties.

  13. The underlying event in hard scattering processes

    International Nuclear Information System (INIS)

    Field, R.

    2002-01-01

    The authors study the behavior of the underlying event in hard scattering proton-antiproton collisions at 1.8 TeV and compare with the QCD Monte-Carlo models. The underlying event is everything except the two outgoing hard scattered jets and receives contributions from the beam-beam remnants plus initial and final-state radiation. The data indicate that neither ISAJET or HERWIG produce enough charged particles (with p T > 0.5 GeV/c) from the beam-beam remnant component and that ISAJET produces too many charged particles from initial-state radiation. PYTHIA which uses multiple parton scattering to enhance the underlying event does the best job describing the data

  14. Biological and ecological aspects of hard ticks

    Directory of Open Access Journals (Sweden)

    Diana Nayibe Polanco Echeverry

    2016-01-01

    Full Text Available Hard ticks are blood-sucking ectoparasites of Ixodidae family. These mites have been always considered disrupting agents of livestock systems, where they are recognized as the cause of economic and production losses. However, their ecological role is important for the dynamic equilibrium of the production systems bovine meat or milk. Knowing their biolog y and ecolog y can shed light on the sanitary decisions made in relation to these organisms. This review article presents issues related to classification, characteristics, and life cycle of hard ticks and relations vector-parasite-host. In addition, it addresses the control of ectoparasites on conventional livestock systems and the implica-tions that these models of intervention might have on agro-ecosystem.

  15. Fixed target electroweak and hard scattering physics

    International Nuclear Information System (INIS)

    Brock, R.; Brown, C.N.; Montgomery, H.E.; Corcoran, M.D.

    1990-02-01

    The possibilities for future physics and experiments involving weak and electromagnetic interactions, neutrino oscillations, general hard scattering and experiments involving nuclear targets were explored. The studies were limited to the physics accessible using fixed target experimentation. While some of the avenues explored turn out to be relatively unrewarding in the light of competition elsewhere in the world, there are a number of positive conclusions reached about experimentation in the energy range available to the Main Injector and Tevatron. Some of the experiments would benefit from the increased intensity available from the Tevatron utilizing the Main Injector, while some require this increase. Finally, some of the experiments would use the Main Injector low energy, high intensity extracted beams directly. A program of electroweak and hard scattering experiments at fixed target energies retains the potential for important contributions to physics. The key to major parts of this program would appear to be the existence of the Main Injector. 115 refs, 17 figs

  16. SURFACES OF HARD-SPHERE SYSTEMS

    Directory of Open Access Journals (Sweden)

    Dietrich Stoyan

    2014-07-01

    Full Text Available In various situations surfaces appear that are formed by systems of hard spheres. Examples are porous layers as surfaces of sand heaps and biofilms or fracture surfaces of concrete. The present paper considers models where a statistically homogeneous system of hard spheres with random radii is intersected by a plane and the surface is formed by the spheres with centers close to this plane. Formulae are derived for various characteristics of such surfaces: for the porosity profile, i.e. the local porosity in dependence on the distance from the section plane and for the geometry of the sphere caps that look above the section plane.It turns out that these characteristics only depend on the first-order characteristics of the sphere system, its sphere density and the sphere radius distribution.Comparison with empirically studied biofilms shows that the model is realistic.

  17. Aespoe hard rock laboratory. Annual report 1992

    International Nuclear Information System (INIS)

    1993-04-01

    The Aespoe hard rock laboratory is being constructed in preparation for the deep geological repository of spent fuel in Sweden. This Annual report 1992 for the Aespoe hard rock laboratory contains an overview of the work conducted. Present work is focused on verification of pre-investigation methods and development of the detailed investigation methodology. Construction of the facility and investigation of the bedrock are being carried out in parallel. December 1992 1925 m of the tunnel has been excavated to a depth of 255 m below surface. An important and integrated part of the work is further refinement of conceptual and numerical models for groundwater flow and radionuclide migration. This work is carried out in cooperation with seven organizations from six countries that participate in the project. (25 refs.)

  18. Hard Spheres on the Primitive Surface

    Science.gov (United States)

    Dotera, Tomonari; Takahashi, Yusuke

    2015-03-01

    Recently hierarchical structures associated with the gyroid in several soft-matter systems have been reported. One of fundamental questions is regular arrangement or tiling on minimal surfaces. We have found certain numbers of hard spheres per unit cell on the gyroid surface are entropically self-organized. Here, new results for the primitive surface are presented. 56/64/72 per unit cell on the primitive minimal surface are entropically self-organized. Numerical evidences for the fluid-solid transition as a function of hard sphere radius are obtained in terms of the acceptance ratio of Monte Carlo moves and order parameters. These arrangements, which are the extensions of the hexagonal arrangement on a flat surface, can be viewed as hyperbolic tiling on the Poincaré disk with a negative Gaussian curvature.

  19. Microfabrication of hard x-ray lenses

    DEFF Research Database (Denmark)

    Stöhr, Frederik

    This thesis deals with the development of silicon compound refractive lenses (Si-CRLs) for shaping hard x-ray beams. The CRLs are to be fabricated using state of the art microfabrication techniques. The primary goal of the thesis work is to produce Si-CRLs with considerably increased structure...... and characterized with respect to their shape. Their optical performances were tested at the European Synchrotron Radiation Facility (ESRF). Two 1D-focusing Si-CRLs suitable as condensers in hard-XRM were developed utilizing the aforementioned two different strategies. The first Si-condenser showed focusing of a 56...... of space for sample surroundings and ensure low-divergent and wide x-ray beams with narrow waists. Both results are substantial improvements to what was available at the start of this thesis work. The challenge of making x-ray objectives in silicon by interdigitation of lenslets alternately focusing...

  20. Anomalous structural transition of confined hard squares.

    Science.gov (United States)

    Gurin, Péter; Varga, Szabolcs; Odriozola, Gerardo

    2016-11-01

    Structural transitions are examined in quasi-one-dimensional systems of freely rotating hard squares, which are confined between two parallel walls. We find two competing phases: one is a fluid where the squares have two sides parallel to the walls, while the second one is a solidlike structure with a zigzag arrangement of the squares. Using transfer matrix method we show that the configuration space consists of subspaces of fluidlike and solidlike phases, which are connected with low probability microstates of mixed structures. The existence of these connecting states makes the thermodynamic quantities continuous and precludes the possibility of a true phase transition. However, thermodynamic functions indicate strong tendency for the phase transition and our replica exchange Monte Carlo simulation study detects several important markers of the first order phase transition. The distinction of a phase transition from a structural change is practically impossible with simulations and experiments in such systems like the confined hard squares.

  1. The hardness test: a real mechanical test

    International Nuclear Information System (INIS)

    Rezakhanlou, R.

    1993-02-01

    During the service life, the mechanical properties of the PWR components change. It is necessary to determine precisely this evolution, but it is not always possible to draw a sample with the adequate size for the characterization. For this latter case we intend to calculate the stress-strain curve of a material from a hardness test results, because it is appropriate for testing on site and do not need any particular sample shape. This paper is the first bibliographical part of a larger study on the relation between the values measured during a hardness test (applied load, indentation diameter) and the mechanical properties of a solid obtained by a traction test. We have treated the problem within the general setting of two solids in contact. Thus, we expose general elastic, elasto-plastic and plastic models describing the indentation of a solid by a rigid indenter

  2. Magnetic hyperthermia with hard-magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kashevsky, Bronislav E., E-mail: bekas@itmo.by [A.V Luikov Heat and Mass Transfer Institute, Belarus Academy of Sciences, P. Brovka str. 15, Minsk 220072 (Belarus); Kashevsky, Sergey B.; Korenkov, Victor S. [A.V Luikov Heat and Mass Transfer Institute, Belarus Academy of Sciences, P. Brovka str. 15, Minsk 220072 (Belarus); Istomin, Yuri P. [N. N. Alexandrov National Cancer Center of Belarus, Lesnoy-2, Minsk 223040 (Belarus); Terpinskaya, Tatyana I.; Ulashchik, Vladimir S. [Institute of Physiology, Belarus Academy of Sciences, Akademicheskaya str. 28, Minsk 220072 (Belarus)

    2015-04-15

    Recent clinical trials of magnetic hyperthermia have proved, and even hardened, the Ankinson-Brezovich restriction as upon magnetic field conditions applicable to any site of human body. Subject to this restriction, which is harshly violated in numerous laboratory and small animal studies, magnetic hyperthermia can relay on rather moderate heat source, so that optimization of the whole hyperthermia system remains, after all, the basic problem predetermining its clinical perspectives. We present short account of our complex (theoretical, laboratory and small animal) studies to demonstrate that such perspectives should be related with the hyperthermia system based on hard-magnetic (Stoner–Wohlfarth type) nanoparticles and strong low-frequency fields rather than with superparamagnetic (Brownian or Neél) nanoparticles and weak high-frequency fields. This conclusion is backed by an analytical evaluation of the maximum absorption rates possible under the field restriction in the ideal hard-magnetic (Stoner–Wohlarth) and the ideal superparamagnetic (single relaxation time) systems, by theoretical and experimental studies of the dynamic magnetic hysteresis in suspensions of movable hard-magnetic particles, by producing nanoparticles with adjusted coercivity and suspensions of such particles capable of effective energy absorption and intratumoral penetration, and finally, by successful treatment of a mice model tumor under field conditions acceptable for whole human body. - Highlights: • Hard-magnetic nanoparticles are shown superior for hyperthetmia to superparamagnetic. • Optimal system parameters are found from magnetic reversal model in movable particle. • Penetrating suspension of HM particles with aggregation-independent SAR is developed. • For the first time, mice with tumors are healed in AC field acceptable for human body.

  3. Mining technology development for hard rock excavation

    International Nuclear Information System (INIS)

    Hustrulid, W.; Cudnick, R.; Trent, R.; Holmberg, R.

    1980-01-01

    A research facility has been established in the granitic gneiss of the CSM Experimental Mine at Idaho Springs, Colorado, for the purpose of evaluating/developing mining, geologic and geotechnical procedures appropriate for use in establishing nuclear waste repositories in hard rock. An experimental room has been excavated using careful blasting procedures. The extent and magnitude of blast damage is being evaluated. Structural geology is being mapped to assess continuity

  4. Hard-tip, soft-spring lithography.

    Science.gov (United States)

    Shim, Wooyoung; Braunschweig, Adam B; Liao, Xing; Chai, Jinan; Lim, Jong Kuk; Zheng, Gengfeng; Mirkin, Chad A

    2011-01-27

    Nanofabrication strategies are becoming increasingly expensive and equipment-intensive, and consequently less accessible to researchers. As an alternative, scanning probe lithography has become a popular means of preparing nanoscale structures, in part owing to its relatively low cost and high resolution, and a registration accuracy that exceeds most existing technologies. However, increasing the throughput of cantilever-based scanning probe systems while maintaining their resolution and registration advantages has from the outset been a significant challenge. Even with impressive recent advances in cantilever array design, such arrays tend to be highly specialized for a given application, expensive, and often difficult to implement. It is therefore difficult to imagine commercially viable production methods based on scanning probe systems that rely on conventional cantilevers. Here we describe a low-cost and scalable cantilever-free tip-based nanopatterning method that uses an array of hard silicon tips mounted onto an elastomeric backing. This method-which we term hard-tip, soft-spring lithography-overcomes the throughput problems of cantilever-based scanning probe systems and the resolution limits imposed by the use of elastomeric stamps and tips: it is capable of delivering materials or energy to a surface to create arbitrary patterns of features with sub-50-nm resolution over centimetre-scale areas. We argue that hard-tip, soft-spring lithography is a versatile nanolithography strategy that should be widely adopted by academic and industrial researchers for rapid prototyping applications.

  5. Hard Diffraction - from Blois 1985 to 2005

    Energy Technology Data Exchange (ETDEWEB)

    Gunnar, Ingelman [Uppsala Univ., High Energy Physics (Sweden)

    2005-07-01

    The idea of diffractive processes with a hard scale involved, to resolve the underlying parton dynamics, was presented at the first Blois conference in 1985 and experimentally verified a few years later. Today hard diffraction is an attractive research field with high-quality data and new theoretical models. The trend from Regge-based pomeron models to QCD-based parton level models has given insights on QCD dynamics involving perturbative gluon exchange mechanisms. In the new QCD-based models, the pomeron is not part of the proton wave function, but diffraction is an effect of the scattering process. Models based on interactions with a colour background field provide an interesting approach which avoids conceptual problems of pomeron-based models, such as the pomeron flux, and provide a basis for common theoretical framework for all final states, diffractive gap events as well as non-diffractive events. Finally, the new process of gaps between jets provides strong evidence for the BFKL dynamics as predicted since long by QCD, but so far hard to establish experimentally.

  6. Hard diffraction and deep inelastic scattering

    International Nuclear Information System (INIS)

    Bjorken, J.D.

    1994-04-01

    Since the advent of hard-collision physics, the study of diffractive processes - shadow physics - has been less prominent than before. However, there is now a renewed interest in the subject, especially in that aspect which synthesizes the short-distance, hard-collision phenomena with the classical physics of large rapidity-gaps. This is especially stimulated by the recent data on deep-inelastic scattering from HERA, as well as the theoretical work which relates to it. The word diffraction is sometimes used by high-energy physicists in a loose way. The author defines this term to mean: A diffractive process occurs if and only if there is a large rapidity gap in the produced-particle phase space which is not exponentially suppressed. Here a rapidity gap means essentially no hadrons produced into the rapidity gap (which operates in the open-quotes legoclose quotes phase-space of pseudo-rapidity and azimuthal angle). And non-exponential suppression implies that the cross-section for creating a gap with width Δη does not have a power-law decrease with increasing subenergy s=e Δη , but behaves at most like some power of pseudorapidity Δη∼log(s). The term hard diffraction shall simply refer to those diffractive process which have jets in the final-state phase-space

  7. Hard and soft acids and bases: atoms and atomic ions.

    Science.gov (United States)

    Reed, James L

    2008-07-07

    The structural origin of hard-soft behavior in atomic acids and bases has been explored using a simple orbital model. The Pearson principle of hard and soft acids and bases has been taken to be the defining statement about hard-soft behavior and as a definition of chemical hardness. There are a number of conditions that are imposed on any candidate structure and associated property by the Pearson principle, which have been exploited. The Pearson principle itself has been used to generate a thermodynamically based scale of relative hardness and softness for acids and bases (operational chemical hardness), and a modified Slater model has been used to discern the electronic origin of hard-soft behavior. Whereas chemical hardness is a chemical property of an acid or base and the operational chemical hardness is an experimental measure of it, the absolute hardness is a physical property of an atom or molecule. A critical examination of chemical hardness, which has been based on a more rigorous application of the Pearson principle and the availability of quantitative measures of chemical hardness, suggests that the origin of hard-soft behavior for both acids and bases resides in the relaxation of the electrons not undergoing transfer during the acid-base interaction. Furthermore, the results suggest that the absolute hardness should not be taken as synonymous with chemical hardness but that the relationship is somewhat more complex. Finally, this work provides additional groundwork for a better understanding of chemical hardness that will inform the understanding of hardness in molecules.

  8. Visual inspection technology in the hard disc drive industry

    CERN Document Server

    Muneesawang, Paisarn

    2015-01-01

    A presentation of the use of computer vision systems to control manufacturing processes and product quality in the hard disk drive industry. Visual Inspection Technology in the Hard Disk Drive Industry is an application-oriented book borne out of collaborative research with the world's leading hard disk drive companies. It covers the latest developments and important topics in computer vision technology in hard disk drive manufacturing, as well as offering a glimpse of future technologies.

  9. Determining the Effect of Material Hardness During the Hard Turning of AISI4340 Steel

    Science.gov (United States)

    Kambagowni, Venkatasubbaiah; Chitla, Raju; Challa, Suresh

    2018-05-01

    In the present manufacturing industries hardened steels are most widely used in the applications like tool design and mould design. It enhances the application range of hard turning of hardened steels in manufacturing industries. This study discusses the impact of workpiece hardness, feed and depth of cut on Arithmetic mean roughness (Ra), root mean square roughness (Rq), mean depth of roughness (Rz) and total roughness (Rt) during the hard turning. Experiments have been planned according to the Box-Behnken design and conducted on hardened AISI4340 steel at 45, 50 and 55 HRC with wiper ceramic cutting inserts. Cutting speed is kept constant during this study. The analysis of variance was used to determine the effects of the machining parameters. 3-D response surface plots drawn based on RSM were utilized to set up the input-output relationships. The results indicated that the feed rate has the most significant parameter for Ra, Rq and Rz and hardness has the most critical parameter for the Rt. Further, hardness shows its influence over all the surface roughness characteristics.

  10. Development of method for evaluating cell hardness and correlation between bacterial spore hardness and durability

    Directory of Open Access Journals (Sweden)

    Nakanishi Koichi

    2012-06-01

    Full Text Available Abstract Background Despite the availability of conventional devices for making single-cell manipulations, determining the hardness of a single cell remains difficult. Here, we consider the cell to be a linear elastic body and apply Young’s modulus (modulus of elasticity, which is defined as the ratio of the repulsive force (stress in response to the applied strain. In this new method, a scanning probe microscope (SPM is operated with a cantilever in the “contact-and-push” mode, and the cantilever is applied to the cell surface over a set distance (applied strain. Results We determined the hardness of the following bacterial cells: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and five Bacillus spp. In log phase, these strains had a similar Young’s modulus, but Bacillus spp. spores were significantly harder than the corresponding vegetative cells. There was a positive, linear correlation between the hardness of bacterial spores and heat or ultraviolet (UV resistance. Conclusions Using this technique, the hardness of a single vegetative bacterial cell or spore could be determined based on Young’s modulus. As an application of this technique, we demonstrated that the hardness of individual bacterial spores was directly proportional to heat and UV resistance, which are the conventional measures of physical durability. This technique allows the rapid and direct determination of spore durability and provides a valuable and innovative method for the evaluation of physical properties in the field of microbiology.

  11. Determination of Formula for Vickers Hardness Measurements Uncertainty

    International Nuclear Information System (INIS)

    Purba, Asli

    2007-01-01

    The purpose of formula determination is to obtain the formula of Vickers hardness measurements uncertainty. The approach to determine the formula: influenced parameters identification, creating a cause and effect diagram, determination of sensitivity, determination of standard uncertainty and determination of formula for Vickers hardness measurements uncertainty. The results is a formula for determination of Vickers hardness measurements uncertainty. (author)

  12. CO2 laser milling of hard tissue

    Science.gov (United States)

    Werner, Martin; Ivanenko, Mikhail; Harbecke, Daniela; Klasing, Manfred; Steigerwald, Hendrik; Hering, Peter

    2007-02-01

    Drilling of bone and tooth tissue belongs to recurrent medical procedures (screw- and pin-bores, bores for implant inserting, trepanation etc.). Small round bores can be in general quickly produced with mechanical drills. Problems arise however by angled drilling, by the necessity to fulfill the drilling without damaging of sensitive soft tissue beneath the bone, or by the attempt to mill precisely noncircular small cavities. We present investigations on laser hard tissue "milling", which can be advantageous for solving these problems. The "milling" is done with a CO2 laser (10.6 μm) with pulse duration of 50 - 100 μs, combined with a PC-controlled galvanic beam scanner and with a fine water-spray, which helps to avoid thermal side-effects. The damaging of underlying soft tissue can be prevented through control of the optical or acoustical ablation signal. The ablation of hard tissue is accompanied with a strong glowing, which is absent during the laser beam action on soft tissue. The acoustic signals from the diverse tissue types exhibit distinct differences in the spectral composition. Also computer image analysis could be a useful tool to control the operation. Laser "milling" of noncircular cavities with 1 - 4 mm width and about 10 mm depth is particularly interesting for dental implantology. In ex-vivo investigations we found conditions for fast laser "milling" of the cavities without thermal damage and with minimal tapering. It included exploration of different filling patterns (concentric rings, crosshatch, parallel lines and their combinations), definition of maximal pulse duration, repetition rate and laser power, optimal position of the spray. The optimized results give evidences for the applicability of the CO2 laser for biologically tolerable "milling" of deep cavities in the hard tissue.

  13. Exact sampling hardness of Ising spin models

    Science.gov (United States)

    Fefferman, B.; Foss-Feig, M.; Gorshkov, A. V.

    2017-09-01

    We study the complexity of classically sampling from the output distribution of an Ising spin model, which can be implemented naturally in a variety of atomic, molecular, and optical systems. In particular, we construct a specific example of an Ising Hamiltonian that, after time evolution starting from a trivial initial state, produces a particular output configuration with probability very nearly proportional to the square of the permanent of a matrix with arbitrary integer entries. In a similar spirit to boson sampling, the ability to sample classically from the probability distribution induced by time evolution under this Hamiltonian would imply unlikely complexity theoretic consequences, suggesting that the dynamics of such a spin model cannot be efficiently simulated with a classical computer. Physical Ising spin systems capable of achieving problem-size instances (i.e., qubit numbers) large enough so that classical sampling of the output distribution is classically difficult in practice may be achievable in the near future. Unlike boson sampling, our current results only imply hardness of exact classical sampling, leaving open the important question of whether a much stronger approximate-sampling hardness result holds in this context. The latter is most likely necessary to enable a convincing experimental demonstration of quantum supremacy. As referenced in a recent paper [A. Bouland, L. Mancinska, and X. Zhang, in Proceedings of the 31st Conference on Computational Complexity (CCC 2016), Leibniz International Proceedings in Informatics (Schloss Dagstuhl-Leibniz-Zentrum für Informatik, Dagstuhl, 2016)], our result completes the sampling hardness classification of two-qubit commuting Hamiltonians.

  14. Seismic loads in modularized and unmodularized large pools located on hard or intermediate hard sites

    Energy Technology Data Exchange (ETDEWEB)

    Dong, R G [California Univ., Livermore (USA). Lawrence Livermore Lab.

    1977-12-01

    To augment the present capacity of pools for storing spent nuclear fuel elements, pools larger than those in current use are being planned. These pools may or may not be modularized into cells. Because of the large size of the pools, seismic loads are of significant interest. In particular, the effects of modularization and site hardness are of concern. The study presented in this paper reveals that modularization is generally unfavourable, because it creates the option of leaving one or more cells empty which in turn results in higher structural loads. The wall which separates a filled cell from an empty cell, or the wall which bears against earth on one side and faces an empty cell on the other, becomes very highly stressed. For the particular pool geometries examined, a hard site is generally preferred over an intermediate hard site in terms of structural loads.

  15. Hard production of exotic hybrid mesons

    Energy Technology Data Exchange (ETDEWEB)

    Anikin, I.; Teryaev, O.V. [Bogoliubov Lab. of Theoretical Physics, JINR, Dubna (Russian Federation); Pire, B.; Anikin, I. [Ecole Polytechnique, CPHT, 91 - Palaiseau (France); Szymanowski, I. [Soltan Institute for Nuclear Studies, Warsaw (Poland); Liege Univ. (Belgium); Anikin, I.; Wallon, S. [Paris-11 Univ., Lab. de Physique Theorique, 91 - Orsay (France)

    2005-07-01

    Exotic hybrid mesons H, with quantum numbers J{sup PC} = 1{sup -+} may be copiously produced in the hard exclusive processes {gamma}{sup *}(Q{sup 2}){gamma} {yields} H and {gamma}{sup *}(Q{sup 2})P(p) {yields} HP(p') because they have a leading twist distribution amplitude with a sizable coupling constant f{sub H}, which may be estimated through QCD sum rules. The reaction rates scale in the same way as the corresponding rates for usual mesons. (authors)

  16. Hardness and Approximation for Network Flow Interdiction

    OpenAIRE

    Chestnut, Stephen R.; Zenklusen, Rico

    2015-01-01

    In the Network Flow Interdiction problem an adversary attacks a network in order to minimize the maximum s-t-flow. Very little is known about the approximatibility of this problem despite decades of interest in it. We present the first approximation hardness, showing that Network Flow Interdiction and several of its variants cannot be much easier to approximate than Densest k-Subgraph. In particular, any $n^{o(1)}$-approximation algorithm for Network Flow Interdiction would imply an $n^{o(1)}...

  17. Nonvolatile Rad-Hard Holographic Memory

    Science.gov (United States)

    Chao, Tien-Hsin; Zhou, Han-Ying; Reyes, George; Dragoi, Danut; Hanna, Jay

    2001-01-01

    We are investigating a nonvolatile radiation-hardened (rad-hard) holographic memory technology. Recently, a compact holographic data storage (CHDS) breadboard utilizing an innovative electro-optic scanner has been built and demonstrated for high-speed holographic data storage and retrieval. The successful integration of this holographic memory breadboard has paved the way for follow-on radiation resistance test of the photorefractive (PR) crystal, Fe:LiNbO3. We have also started the investigation of using two-photon PR crystals that are doubly doped with atoms of iron group (Ti, Cr, Mn, Cu) and of rare-earth group (Nd, Tb) for nonvolatile holographic recordings.

  18. Hard target LIDAR calibration for SO2

    CSIR Research Space (South Africa)

    Du Plessis, A

    2006-01-01

    Full Text Available calibration for SO2 A du Plessis, DE Roberts CSIR National Laser Centre, Pretoria Slide 2 © CSIR 2006 www.csir.co.za Project background • Las-R-MAP: Laser – Remote – Measurement of Atmospheric Pollutants • Mobile laser system....csir.co.za Hard target backscatter ∫ = − R dRRn p e R RcE RS 0 )(2 2 )()( λσ λ β S R Slide 10 © CSIR 2006 www.csir.co.za Las-R-MAP hardware: laser system Slide 11 © CSIR 2006 www.csir.co.za Las-R...

  19. Tomography for amplitudes of hard exclusive processes

    International Nuclear Information System (INIS)

    Polyakov, M.V.

    2008-01-01

    We discuss which part of information about hadron structure encoded in the Generalized Parton Distributions (GPDs) [part of total GPD image] can be restored from the known amplitude of a hard exclusive process. The physics content of this partial image is analyzed. Among other things, we show that this partial image contains direct information about how the target hadron responses to the (string) quark-antiquark operator of arbitrary spin J. Explicit equations relating physics content of the partial image of GPDs directly to the data are derived. Also some new results concerning the dual parametrization of GPDs are presented

  20. Design of Vickers Hardness Loading Controller

    Directory of Open Access Journals (Sweden)

    Sihai Zhao

    2014-09-01

    Full Text Available Traditionally Vickers testing needs manual works, as a result, it will induce low precision and automatization. So this paper design a new type of loading controlling system, it is based on single chip computer 89S52, used PZT as the force generator in micro Vickers hardness testing. It primarily includes the designing of hardware, software of collecting data and PZT signals by AD667. This article has given the sketch of electrical circuit and controlling software, it also offers the experiment data. The experiments have showed that using this system can exactly control the loading results, and the average tolerance is less than 0.43 %.

  1. Hard diffraction at HERA and Tevatron

    International Nuclear Information System (INIS)

    Kaidalov, A.B.

    2001-01-01

    A relation between hard diffraction at HERA and Tevatron is discussed. A model, which takes into account unitarity effects is developed for interaction of high-energy virtual photons with nucleons. It is shown that this model gives a good description of HERA data on both total γ* p total cross section and diffractive dissociation of virtual photons in a broad region of Q 2 . It is shown how to describe the CDF data on diffractive jet production at Tevatron using an information on distribution of partons in the Pomeron from HERA experiments

  2. Sorption of radionuclides on hard rocks

    International Nuclear Information System (INIS)

    Berry, J.A.; Bourke, P.J.; Green, A.; Littleboy, A.K.

    1987-09-01

    Methods for measuring sorption on hard rocks, particularly of strontium, caesium, neptunium and americium on Darley Dale sandstone and Welsh slate have been investigated. The methods tried included batch tests with crushed rock and tests of simultaneous diffusion and convection with sorption on intact rock. High pressures (800m H 2 O) were used in the convective tests to pump water quickly through the rock samples and to measure high sorptivities in times shorter than those needed in the diffusive methods with intact samples. (author)

  3. Burning actinides in very hard spectrum reactors

    International Nuclear Information System (INIS)

    Robinson, A.H.; Shirley, G.W.; Prichard, A.W.; Trapp, T.J.

    1978-01-01

    The major unresolved problem in the nuclear industry is the ultimate disposition of the waste products of light water reactors. The study demonstrates the feasibility of designing a very hard spectrum actinide burner reactor (ABR). A 1100 MW/sub t/ ABR design fueled entirely with actinides reprocessed from light water reactor (LWR) wastes is proposed as both an ultimate disposal mechanism for actinides and a means of concurrently producing usable power. Actinides from discharged ABR fuel are recycled to the ABR while fission products are routed to a permanent repository. As an integral part of a large energy park, each such ABR would dispose of the waste actinides from 2 LWRs

  4. Studying Hardness Meter Spring Strength to Understand Hardness Distribution on Body Surfaces.

    Science.gov (United States)

    Arima, Yoshitaka

    2017-10-01

    For developing a hardness multipoint measurement system for understanding hardness distribution on biological body surfaces, we investigated the spring strength of the contact portion main axis of a biological tissue hardness meter (product name: PEK). We measured the hardness of three-layered sheets of six types of gel sheets (90 mm × 60 mm × 6 mm) constituting the acupuncture practice pads, with PEK measurements of 1.96 N, 2.94 N, 3.92 N, 4.90 N, 5.88 N, 6.86 N, 7.84 N, 8.82 N, and 9.81 N of the main axis spring strength. We obtained measurements 10 times for the gel sheets and simultaneously measured the load using a digital scale. We measured the hardness distribution of induration embedded and breast cancer palpation models, with a main axis with 1.96 N, 4.90 N, and 9.81 N spring strengths, to create a two-dimensional Contour Fill Chart. Using 4.90 N spring strength, we could obtain measurement loads of ≤3.0 N, and the mean hardness was 5.14 mm. This was close to the median of the total measurement range 0.0-10.0 mm, making the measurement range the largest for this spring strength. We could image the induration of the induration-embedded model regardless of the spring strength. Overall, 4.90 N spring strength was best suited for imaging cancer in the breast cancer palpation model. Copyright © 2017. Published by Elsevier B.V.

  5. Genetic analysis of kernel texture (grain hardness) in a hard red spring wheat (Triticum aestivum L.) bi-parental population

    Science.gov (United States)

    Grain hardness is a very important trait in determining wheat market class and also influences milling and baking traits. At the grain Hardness (Ha) locus on chromosome 5DS, there are two primary mutations responsible for conveying a harder kernel texture among U.S. hard red spring wheats: (1) the P...

  6. Study of Cu-Al-Zn alloys hardness temperature dependence

    International Nuclear Information System (INIS)

    Kurmanova, D.T.; Skakov, M.K.; Melikhov, V.D.

    2001-01-01

    In the paper the results of studies for the Cu-Al-Zn ternary alloys hardness temperature dependence are presented. The method of 'hot hardness' has been used during study of the solid state phase transformations and under determination of the hot stability boundaries. Due to the samples brittleness a hardness temperature dependence definition is possible only from 350-400 deg. C. Sensitivity of the 'hot hardness' method is decreasing within high plasticity range, so the measurements have been carried out only up to 700-800 deg. C. It is shown, that the alloys hardness dependence character from temperature is close to exponential one within the certain structure modification existence domain

  7. Hard And Soft QCD Physics In ATLAS

    Directory of Open Access Journals (Sweden)

    Adomeit Stefanie

    2014-04-01

    Full Text Available Hard and soft QCD results using proton-proton collisions recorded with the ATLAS detector at the LHC are reported. Charged-particle distributions and forward-backward correlations have been studied in low-luminosity minimum bias data taken at centre-of-mass energies of √s = 0.9, 2.36 and 7 TeV. Recent measurements on underlying event characteristics using charged-particle jets are also presented. The results are tested against various phenomenological soft QCD models implemented in Monte-Carlo generators. A summary of hard QCD measurements involving high transverse momentum jets is also given. Inclusive jet and dijet cross-sections have been measured at a centre-of-mass energy of 7 TeV and are compared to expectations based on NLO pQCD calculations corrected for non-perturbative effects as well as to NLO Monte Carlo predictions. Recent studies exploiting jet substructure techniques to identify hadronic decays of boosted massive particles are reported.

  8. Hard processes in photon-photon interactions

    International Nuclear Information System (INIS)

    Duchovni, E.

    1985-03-01

    In this thesis, the existence of hard component in two-photon collisions is investigated. Due to the relative simplicity of the photon, such processes can be exactly calculated in QCD. Untagged (low Q 2 ) two-photon events are used. This leads to relatively high statistics, but to severe background problem due mainly to e + e - annihilation. The background contamination is reduced to a tolerable level using a special set of cuts. Moreover, the remaining contamination is shown to be calculable with a small systematic error. A large number of events of the hard ''γγ'' type is found. An attempt to explain these events using the simplest QCD diagram (the Born term) is done. This process is found to be capable of explaining only a 1/4 of the data. Other options like the constituent intercharge model, integer charged quarks, and higher order diagrams are therefore also discussed. The large cross-section for the production of ρ 0 ρ 0 pairs in ''γγ'' collisions has not been understood yet. Inorder to look at closely related processes, a search for φρ 0 and φφ was initiated. The cross-section for θπ + π - was found to be sizeable. Only upper limits for the production of φρ 0 and φφ are obtained

  9. Exotic hybrid mesons in hard electroproduction

    International Nuclear Information System (INIS)

    Anikin, I.V.; Pire, B.; Szymanowski, L.; Teryaev, O.V.; Wallon, S.

    2005-01-01

    We estimate the sizeable cross section for deep exclusive electroproduction of an exotic J PC =1 -+ hybrid meson in the Bjorken regime. The production amplitude scales like the one for usual meson electroproduction, i.e., as 1/Q 2 . This is due to the nonvanishing leading twist distribution amplitude for the hybrid meson, which may be normalized thanks to its relation to the energy-momentum tensor and to the QCD sum rules technique. The hard amplitude is considered up to next-to-leading order in α S and we explore the consequences of fixing the renormalization scale ambiguity through the Brodsky-Lepage-Mackenzie (BLM) procedure. We study the particular case where the hybrid meson decays through a πη meson pair. We discuss the πη generalized distribution amplitude and then calculate the production amplitude for this process. We propose a forward-backward asymmetry in the production of π and η mesons as a signal for the hybrid meson production. We briefly comment on hybrid electroproduction at very high energy, in the diffractive limit where a QCD Odderon exchange mechanism should dominate. The conclusion of our study is that hard electroproduction is a promising way to study exotic hybrid mesons, in particular, at JLAB, HERA (HERMES), or CERN (Compass)

  10. [Computer-assisted phacoemulsification for hard cataracts].

    Science.gov (United States)

    Zemba, M; Papadatu, Adriana-Camelia; Sîrbu, Laura-Nicoleta; Avram, Corina

    2012-01-01

    to evaluate the efficiency of new torsional phacoemulsification software (Ozil IP system) in hard nucleus cataract extraction. 45 eyes with hard senile cataract (degree III and IV) underwent phacoemulsification performed by the same surgeon, using the same technique (stop and chop). Infiniti (Alcon) platform was used, with Ozil IP software and Kelman phaco tip miniflared, 45 degrees. The nucleus was split into two and after that the first half was phacoemulsificated with IP-on (group 1) and the second half with IP-off (group 2). For every group we measured: cumulative dissipated energy (CDE), numbers of tip closure that needed manual desobstruction the amount of BSS used. The mean CDE was the same in group 1 and in group 2 (between 6.2 and 14.9). The incidence of occlusion that needed manual desobstruction was lower in group 1 (5 times) than in group 2 (13 times). Group 2 used more BSS compared to group 1. The new torsional software (IP system) significantly decreased occlusion time and balanced salt solution use over standard torsional software, particularly with denser cataracts.

  11. Statistical physics of hard optimization problems

    International Nuclear Information System (INIS)

    Zdeborova, L.

    2009-01-01

    Optimization is fundamental in many areas of science, from computer science and information theory to engineering and statistical physics, as well as to biology or social sciences. It typically involves a large number of variables and a cost function depending on these variables. Optimization problems in the non-deterministic polynomial (NP)-complete class are particularly difficult, it is believed that the number of operations required to minimize the cost function is in the most difficult cases exponential in the system size. However, even in an NP-complete problem the practically arising instances might, in fact, be easy to solve. The principal question we address in this article is: How to recognize if an NP-complete constraint satisfaction problem is typically hard and what are the main reasons for this? We adopt approaches from the statistical physics of disordered systems, in particular the cavity method developed originally to describe glassy systems. We describe new properties of the space of solutions in two of the most studied constraint satisfaction problems - random satisfy ability and random graph coloring. We suggest a relation between the existence of the so-called frozen variables and the algorithmic hardness of a problem. Based on these insights, we introduce a new class of problems which we named ”locked” constraint satisfaction, where the statistical description is easily solvable, but from the algorithmic point of view they are even more challenging than the canonical satisfy ability.

  12. Recent developments in hard magnetic materials

    International Nuclear Information System (INIS)

    Asti, G.

    1989-01-01

    Hard magnetic materials find ever-increasing uses in modern technology. Their importance is mainly in the domain of permanent magnets, but a variety of other applications is being offered to this class of materials, especially for what regards the areas of information storage, telecommunications and special electronic devices. These developments are connected to the emphasis that is more and more given to thin films having high magnetic anisotropy. The recent advancement in the field of hard magnetic materials is among the best examples where technology depends to a great extent upon the continuous progress in the scientific knowledge. The research activity is characterized by the introduction of new classes of materials and continuous improvements in the preparation techniques both for what regards industrial processing and method for obtaining high quality materials in form of crystals, films or amorphous specimens. In this respect a special place must be reserved to rare earth transition metal compounds, a class of materials that attracted enormeous attention after the discovery by Hoffer and Strnat in 1966 of the large uniaxial magnetocrystalline anisotropy of the compound YCo 5 . Beside the so called 1:5 phase, other compositions of technical importance are the 2:17 and the recently discovered Nd 2 Fe 14 B, which is a real new ternary phase having tetragonal crystal structure. Great efforts have been done to gain a better understanding of the magnetic anisotropy and its relationship to the coercivity is of leading importance for a further development in this important area of magnetism. (orig.)

  13. Statistical physics of hard optimization problems

    International Nuclear Information System (INIS)

    Zdeborova, L.

    2009-01-01

    Optimization is fundamental in many areas of science, from computer science and information theory to engineering and statistical physics, as well as to biology or social sciences. It typically involves a large number of variables and a cost function depending on these variables. Optimization problems in the non-deterministic polynomial-complete class are particularly difficult, it is believed that the number of operations required to minimize the cost function is in the most difficult cases exponential in the system size. However, even in an non-deterministic polynomial-complete problem the practically arising instances might, in fact, be easy to solve. The principal the question we address in the article is: How to recognize if an non-deterministic polynomial-complete constraint satisfaction problem is typically hard and what are the main reasons for this? We adopt approaches from the statistical physics of disordered systems, in particular the cavity method developed originally to describe glassy systems. We describe new properties of the space of solutions in two of the most studied constraint satisfaction problems - random satisfiability and random graph coloring. We suggest a relation between the existence of the so-called frozen variables and the algorithmic hardness of a problem. Based on these insights, we introduce a new class of problems which we named 'locked' constraint satisfaction, where the statistical description is easily solvable, but from the algorithmic point of view they are even more challenging than the canonical satisfiability (Authors)

  14. Statistical physics of hard optimization problems

    Science.gov (United States)

    Zdeborová, Lenka

    2009-06-01

    Optimization is fundamental in many areas of science, from computer science and information theory to engineering and statistical physics, as well as to biology or social sciences. It typically involves a large number of variables and a cost function depending on these variables. Optimization problems in the non-deterministic polynomial (NP)-complete class are particularly difficult, it is believed that the number of operations required to minimize the cost function is in the most difficult cases exponential in the system size. However, even in an NP-complete problem the practically arising instances might, in fact, be easy to solve. The principal question we address in this article is: How to recognize if an NP-complete constraint satisfaction problem is typically hard and what are the main reasons for this? We adopt approaches from the statistical physics of disordered systems, in particular the cavity method developed originally to describe glassy systems. We describe new properties of the space of solutions in two of the most studied constraint satisfaction problems - random satisfiability and random graph coloring. We suggest a relation between the existence of the so-called frozen variables and the algorithmic hardness of a problem. Based on these insights, we introduce a new class of problems which we named "locked" constraint satisfaction, where the statistical description is easily solvable, but from the algorithmic point of view they are even more challenging than the canonical satisfiability.

  15. Hard-Boiled for Hard Times in Leonardo Padura Fuentes's Detective Fiction

    Science.gov (United States)

    Song, H. Rosi

    2009-01-01

    Focusing on Leonardo Padura Fuentes's hard-boiled fiction, this essay traces the origin and evolution of the genre in Cuba. Padura Fuentes has challenged the officially sanctioned socialist "literatura policial" that became popular in the 1970s and 1980s. creating a new model of criticism that is not afraid to confront the island's socio-economic…

  16. Optical fiber composition and radiation hardness

    International Nuclear Information System (INIS)

    Wall, J.A.; Loretz, T.J.

    1982-01-01

    Germanium phosphosilicate and germanium borosilicate fibers doped with cerium were fabricated and tested for their responses to steady-state Co-60 radiation at -55 C, +20 C and +125 C. A fiber with germanium, boron and phosphorous in the silicate core and doped with antimony in the core and clad was similarly tested. All of the fibers showed significant improvements in radiation hardness at 20 C compared to undoped fibers of the same base composition. At -55 C, however, all except the cerium doped germanium phosphosilicate were very radiation sensitive and also showed increases in the rate of induced loss at +125 C. The cerium doped germanium phosphosilicate fiber showed virtually no change in radiation sensitivity at the temperature extremes and could prove useful in applications requiring relatively short lengths of fiber

  17. Imaging the hard/soft tissue interface.

    Science.gov (United States)

    Bannerman, Alistair; Paxton, Jennifer Z; Grover, Liam M

    2014-03-01

    Interfaces between different tissues play an essential role in the biomechanics of native tissues and their recapitulation is now recognized as critical to function. As a consequence, imaging the hard/soft tissue interface has become increasingly important in the area of tissue engineering. Particularly as several biotechnology based products have made it onto the market or are close to human trials and an understanding of their function and development is essential. A range of imaging modalities have been developed that allow a wealth of information on the morphological and physical properties of samples to be obtained non-destructively in vivo or via destructive means. This review summarizes the use of a selection of imaging modalities on interfaces to date considering the strengths and weaknesses of each. We will also consider techniques which have not yet been utilized to their full potential or are likely to play a role in future work in the area.

  18. Controlling grass weeds on hard surfaces

    DEFF Research Database (Denmark)

    Rask, Anne Merete; Kristoffersen, Palle; Andreasen, Christian

    2012-01-01

    An experiment was conducted on a specially designed hard surface to study the impact of time interval between flaming treatments on the regrowth and flower production of two grass weeds. The goal of this experiment was to optimize the control of annual bluegrass and perennial ryegrass, both species...... that are very difficult to control without herbicides. Aboveground biomass from 72 plants per treatment was harvested and dry weights were recorded at regular intervals to investigate how the plants responded to flaming. Regrowth of the grasses was measured by harvesting aboveground biomass 2 wk after......, as they did not increase the reduction of aboveground biomass compared with the 7-d treatment interval. Knowledge on the regrowth of grass weeds after flaming treatments provided by this study can help improve recommendations given to road keepers and park managers for management on these weeds. Nomenclature...

  19. Aespoe Hard Rock Laboratory. Annual Report 2011

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-03-15

    The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. Aespoe HRL is located in the Simpevarp area in the municipality of Oskarshamn. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create opportunities for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its research, as well as in the development and demonstration tasks. A summary of the work performed at Aespoe HRL during 2011 is given below.

  20. Aespoe hard rock laboratory. Annual report 2010

    Energy Technology Data Exchange (ETDEWEB)

    2011-02-15

    The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. Aespoe HRL is located in the Simpevarp area in the municipality of Oskarshamn. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create opportunities for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its research, as well as in the development and demonstration tasks. A summary of the work performed at Aespoe HRL during 2010 is given below

  1. Hard Probes in Heavy-Ion Physics

    CERN Document Server

    Renk, Thorsten

    2012-01-01

    The aim of ultrarelativistic heavy ion physics is to study collectivity and thermodynamics of Quantum Chromodynamics (QCD) by creating a transient small volume of matter with extreme density and temperature. There is experimental evidence that most of the particles created in such a collision form indeed a thermalized system characterized by collective response to pressure gradients. However, a numerically small subset of high transverse momentum ($P_T$) processes takes place independent of the bulk, with the outgoing partons subsequently propagating through the bulk medium. Understanding the modification of such 'hard probes' by the bulk medium is an important part of the efforts to determine the properties of hot and dense QCD matter. In this paper, current developments are reviewed.

  2. Aespoe Hard Rock Laboratory. Annual Report 2011

    International Nuclear Information System (INIS)

    2012-03-01

    The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. Aespoe HRL is located in the Simpevarp area in the municipality of Oskarshamn. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create opportunities for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its research, as well as in the development and demonstration tasks. A summary of the work performed at Aespoe HRL during 2011 is given below

  3. Blazars in Hard X-rays

    Science.gov (United States)

    Ghisellini, Gabriele

    2009-05-01

    Although blazars are thought to emit most of their luminosity in the γ-ray band, there are subclasses of them very prominent in hard X-rays. These are the best candidates to be studied by Simbol-X. They are at the extremes of the blazar sequence, having very small or very high jet powers. The former are the class of TeV emitting BL Lacs, whose synchrotron emission often peaks at tens of keV or more. The latter are the blazars with the most powerful jets, have high black hole masses accreting at high (i.e. close to Eddington) rates. These sources are predicted to have their high energy peak even below the MeV band, and therefore are very promising candidates to be studied with Simbol-X.

  4. Static structure of active Brownian hard disks

    Science.gov (United States)

    de Macedo Biniossek, N.; Löwen, H.; Voigtmann, Th; Smallenburg, F.

    2018-02-01

    We explore the changes in static structure of a two-dimensional system of active Brownian particles (ABP) with hard-disk interactions, using event-driven Brownian dynamics simulations. In particular, the effect of the self-propulsion velocity and the rotational diffusivity on the orientationally-averaged fluid structure factor is discussed. Typically activity increases structural ordering and generates a structure factor peak at zero wave vector which is a precursor of motility-induced phase separation. Our results provide reference data to test future statistical theories for the fluid structure of active Brownian systems. This manuscript was submitted for the special issue of the Journal of Physics: Condensed Matter associated with the Liquid Matter Conference 2017.

  5. Aespoe hard rock laboratory. Annual report 2010

    International Nuclear Information System (INIS)

    2011-02-01

    The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. Aespoe HRL is located in the Simpevarp area in the municipality of Oskarshamn. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create opportunities for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its research, as well as in the development and demonstration tasks. A summary of the work performed at Aespoe HRL during 2010 is given below

  6. Nanomechanics of hard films on compliant substrates.

    Energy Technology Data Exchange (ETDEWEB)

    Reedy, Earl David, Jr. (Sandia National Laboratories, Albuquerque, NM); Emerson, John Allen (Sandia National Laboratories, Albuquerque, NM); Bahr, David F. (Washington State University, Pullman, WA); Moody, Neville Reid; Zhou, Xiao Wang; Hales, Lucas (University of Minnesota, Minneapolis, MN); Adams, David Price (Sandia National Laboratories, Albuquerque, NM); Yeager,John (Washington State University, Pullman, WA); Nyugen, Thao D. (Johns Hopkins University, Baltimore, MD); Corona, Edmundo (Sandia National Laboratories, Albuquerque, NM); Kennedy, Marian S. (Clemson University, Clemson, SC); Cordill, Megan J. (Erich Schmid Institute, Leoben, Austria)

    2009-09-01

    a result, our understanding of the critical relationship between adhesion, properties, and fracture for hard films on compliant substrates is limited. To address this issue, we integrated nanomechanical testing and mechanics-based modeling in a program to define the critical relationship between deformation and fracture of nanoscale films on compliant substrates. The approach involved designing model film systems and employing nano-scale experimental characterization techniques to isolate effects of compliance, viscoelasticity, and plasticity on deformation and fracture of thin hard films on substrates that spanned more than two orders of compliance magnitude exhibit different interface structures, have different adhesion strengths, and function differently under stress. The results of this work are described in six chapters. Chapter 1 provides the motivation for this work. Chapter 2 presents experimental results covering film system design, sample preparation, indentation response, and fracture including discussion on the effects of substrate compliance on fracture energies and buckle formation from existing models. Chapter 3 describes the use of analytical and finite element simulations to define the role of substrate compliance and film geometry on the indentation response of thin hard films on compliant substrates. Chapter 4 describes the development and application of cohesive zone model based finite element simulations to determine how substrate compliance affects debond growth. Chapter 5 describes the use of molecular dynamics simulations to define the effects of substrate compliance on interfacial fracture of thin hard tungsten films on silicon substrates. Chapter 6 describes the Workshops sponsored through this program to advance understanding of material and system behavior.

  7. Shock compression synthesis of hard materials

    Energy Technology Data Exchange (ETDEWEB)

    Willson, C.G. [Univ. of Texas, Austin, TX (United States). Dept. of Chemistry

    1999-03-01

    The purpose of this research was to adapt the high explosives technology that was developed in conjunction with nuclear weapons programs to subjecting materials to ultra-high pressures and to explore the utility of this technique for the synthesis of hard materials. The research was conducted in collaboration with researchers at the University of Texas, Texas Tech University and Pantex (Mason and Hanger Corp.). The group designed, modeled, built, and tested a new device that allows quantitative recovery of grams of material that have been subjected to unprecedented pressures. The modeling work was done at Texas Tech and Pantex. The metal parts and material samples were made at the University of Texas, and Pantex machined the explosives, assembled the devices and conducted the detonations. Sample characterization was carried out at the University of Texas and Texas Tech.

  8. Radiation hardness assurances categories for COTS technologies

    International Nuclear Information System (INIS)

    Hash, G.L.; Shaneyfelt, M.R.; Sexton, F.W.; Winokur, P.S.

    1997-01-01

    A comparison of the radiation tolerance of three commercial, and one radiation hardened SRAM is presented for four radiation environments. This work has shown the difficulty associated with strictly categorizing a device based solely on its radiation response, since its category depends on the specific radiation environment considered. For example, the 3.3-V Paradigm SRAM could be considered a radiation-tolerant device except for its SEU response. A more useful classification depends on the methods the manufacturer uses to ensure radiation hardness, i.e. whether specific design and process techniques have been used to harden the device. Finally, this work has shown that burned-in devices may fail functionally as much as 50% lower in total dose environments than non-burned-in devices. No burn-in effect was seen in dose-rate upset, latchup, or SEE environments. The user must ensure that total dose lot acceptance testing was performed on burned-in devices

  9. Toxicity removal from hard board wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Nawar, S.S.; El Kamah, H.

    1984-01-01

    The rapid growth of industry in Egypt in recent years has made industrial pollution an important issue. During the past decade fish production in some canals and lakes have virtually ceased due to the discharge of industrial and agricultural wastewater. The alternatives under study include effluent treatment before discharge to receiving water. Highly polluted waste from a hard board mill was treated using the activated sludge process. Factors affecting the efficiency of the treatment were detention time and organic loading rate. The results indicated that BOD and phenol reduction reached 82% and 94% respectively, when the organic loading rate was 0.1 (kg BOD/kg SS). The process proved to be successful in completely eliminating the toxicity effect of the waste on Nile fish (Tilapia nilotica). 14 references, 1 figure, 3 tables.

  10. Hard exclusive meson production to constrain GPDs

    Energy Technology Data Exchange (ETDEWEB)

    Wolbeek, Johannes ter; Fischer, Horst; Gorzellik, Matthias; Gross, Arne; Joerg, Philipp; Koenigsmann, Kay; Malm, Pasquale; Regali, Christopher; Schmidt, Katharina; Sirtl, Stefan; Szameitat, Tobias [Physikalisches Institut, Albert-Ludwigs-Universitaet Freiburg, Freiburg im Breisgau (Germany); Collaboration: COMPASS Collaboration

    2014-07-01

    The concept of Generalized Parton Distributions (GPDs) combines the two-dimensional spatial information, given by form factors, with the longitudinal momentum information from the PDFs. Thus, GPDs provide a three-dimensional 'tomography' of the nucleon. Furthermore, according to Ji's sum rule, the GPDs H and E enable access to the total angular momenta of quarks, antiquarks and gluons. While H can be approached using electroproduction cross section, hard exclusive meson production off a transversely polarized target can help to constrain the GPD E. At the COMPASS experiment at CERN, two periods of data taking were performed in 2007 and 2010, using a longitudinally polarized 160 GeV/c muon beam and a transversely polarized NH{sub 3} target. This talk introduces the data analysis of the process μ + p → μ' + p' + V, and recent results are presented.

  11. Aespoe hard rock laboratory. Annual report 2010

    Energy Technology Data Exchange (ETDEWEB)

    2011-02-15

    The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. Aespoe HRL is located in the Simpevarp area in the municipality of Oskarshamn. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create opportunities for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its research, as well as in the development and demonstration tasks. A summary of the work performed at Aespoe HRL during 2010 is given below

  12. Gloss evaluation from soft and hard metrologies.

    Science.gov (United States)

    Wang, Zihao; Xu, Lihao; Hu, Yu; Mirjalili, Fereshteh; Luo, Ming Ronnier

    2017-09-01

    Recent advances in bidirectional reflectance distribution function (BRDF) acquisitions have provided a novel approach for appearance measurement and analysis. In particular, since gloss appearance is dependent on the directional reflective properties of surfaces, it is reasonable to leverage the BRDF for gloss evaluation. In this paper, we investigate gloss appearance from both soft metrology and hard metrology. A psychophysical experiment was conducted for the gloss assessment of 47 neutral-color samples. In the evaluation of gloss perception from gloss meter measurements, we report several ambiguous correspondences in the medium gloss range. In order to analyze and explain this phenomenon, the BRDF was acquired and examined using a commercial BRDF measuring device. With an improved correlation-to-visual perception, we propose a two-dimensional gloss model by combining a parameter, the standard deviation of the specular lobe, from Ward's BRDF model with measured gloss values.

  13. MAGNESIUM, DRINKING WATER HARDNESS AND CARDIOVASCULAR DISEASE

    Directory of Open Access Journals (Sweden)

    Dragana Nikic

    2006-01-01

    Full Text Available Many different countries suggest and justify an integrated laboratory and epidemiological research program with an aim to reject or accept the magnesium – CVD (cardiovascular disease hypothesis. The studies shown in this paper that have investigated the relationship between water hardness, especially magnesium and CVD indicate that, even though there has been an ongoing research for nearly half a century (1957-2004, it has not been completed yet. Different study designs (obductional, clinical, ecological, case-control and cohort restrict an adequate comparison of their results as well as the deduction of results applicable on each territorial level.The majority of researchers around the world, using populational and individual studies, have found an inverse (protective association between mortality and morbidity from CVD and the increase in water hardness, especially the increase in the concentration of magnesium. The most frequent benefit of the water with an optimal mineral composition is the reduction of mortality from ischemic heart disease.It was suggested that Mg from water is a supplementary source of Mg of high biological value, because magnesium from water is absorbed around 30% better than Mg in a diet. The vast majority of studies consider lower concentrations of Mg in the water, in the range of 10% of the total daily intake of Mg.Future research efforts must give better answers to low Mg concentrations in the drinking water, before any concrete recommendations are given to the public. Moreover, the researchers must also determine which chemical form of Mg is most easily absorbed and has the greatest impact.Additional research is necessary in order to further investigate the interrelation between different water and food components as well as individual risk factors in the pathogenesis of CVD.

  14. Coendangered hard-ticks: threatened or threatening?

    Directory of Open Access Journals (Sweden)

    Cozma Vasile

    2011-05-01

    Full Text Available Abstract The overwhelming majority of animal conservation projects are focused on vertebrates, despite most of the species on Earth being invertebrates. Estimates state that about half of all named species of invertebrates are parasitic in at least one stage of their development. The dilemma of viewing parasites as biodiversity or pest has been discussed by several authors. However, ticks were omitted. The latest taxonomic synopses of non-fossil Ixodidae consider valid 700 species. Though, how many of them are still extant is almost impossible to tell, as many of them are known only from type specimens in museums and were never collected since their original description. Moreover, many hosts are endangered and as part of conservation efforts of threatened vertebrates, a common practice is the removal of, and treatment for external parasites, with devastating impact on tick populations. There are several known cases when the host became extinct with subsequent coextinction of their ectoparasites. For our synoptic approach we have used the IUCN status of the host in order to evaluate the status of specifically associated hard-ticks. As a result, we propose a number of 63 coendangered and one extinct hard-tick species. On the other side of the coin, the most important issue regarding tick-host associations is vectorial transmission of microbial pathogens (i.e. viruses, bacteria, protozoans. Tick-borne diseases of threatened vertebrates are sometimes fatal to their hosts. Mortality associated with pathogens acquired from ticks has been documented in several cases, mostly after translocations. Are ticks a real threat to their coendangered host and should they be eliminated? Up to date, there are no reliable proofs that ticks listed by us as coendangered are competent vectors for pathogens of endangered animals.

  15. Germanium content in Polish hard coals

    Directory of Open Access Journals (Sweden)

    Makowska Dorota

    2016-01-01

    Full Text Available Due to the policy of the European Union, it is necessary to search for new sources of scarce raw materials. One of these materials is germanium, listed as a critical element. This semi-metal is widely used in the electronics industry, for example in the production of semiconductors, fibre optics and solar cells. Coal and fly ash from its combustion and gasification for a long time have been considered as a potential source of many critical elements, particularly germanium. The paper presents the results of germanium content determination in the Polish hard coal. 23 coal samples of various coal ranks were analysed. The samples were collected from 15 mines of the Upper Silesian Coal Basin and from one mine of the Lublin Coal Basin. The determination of germanium content was performed with the use of Atomic Absorption Spectrometry with Electrothermal Atomization (GFAAS. The investigation showed that germanium content in the analysed samples was at least twice lower than the average content of this element in the hard coals analysed so far and was in the range of 0.08 ÷ 1.28 mg/kg. Moreover, the content of Ge in the ashes from the studied coals does not exceed 15 mg/kg, which is lower than the average value of Ge content in the coal ashes. The highest content of this element characterizes coals of the Lublin Coal Basin and young coals type 31 from the Vistula region. The results indicate a low utility of the analysed coal ashes as a source of the recovery of germanium. On the basis of the analyses, the lack of the relationship between the content of the element and the ash content in the tested coals was noted. For coals of the Upper Silesian Coal Basin, the relationship between the content of germanium in the ashes and the depth of the seam was observed.

  16. 3D Bioprinting Technologies for Hard Tissue and Organ Engineering

    Science.gov (United States)

    Wang, Xiaohong; Ao, Qiang; Tian, Xiaohong; Fan, Jun; Wei, Yujun; Hou, Weijian; Tong, Hao; Bai, Shuling

    2016-01-01

    Hard tissues and organs, including the bones, teeth and cartilage, are the most extensively exploited and rapidly developed areas in regenerative medicine field. One prominent character of hard tissues and organs is that their extracellular matrices mineralize to withstand weight and pressure. Over the last two decades, a wide variety of 3D printing technologies have been adapted to hard tissue and organ engineering. These 3D printing technologies have been defined as 3D bioprinting. Especially for hard organ regeneration, a series of new theories, strategies and protocols have been proposed. Some of the technologies have been applied in medical therapies with some successes. Each of the technologies has pros and cons in hard tissue and organ engineering. In this review, we summarize the advantages and disadvantages of the historical available innovative 3D bioprinting technologies for used as special tools for hard tissue and organ engineering. PMID:28773924

  17. 3D Bioprinting Technologies for Hard Tissue and Organ Engineering

    Directory of Open Access Journals (Sweden)

    Xiaohong Wang

    2016-09-01

    Full Text Available Hard tissues and organs, including the bones, teeth and cartilage, are the most extensively exploited and rapidly developed areas in regenerative medicine field. One prominent character of hard tissues and organs is that their extracellular matrices mineralize to withstand weight and pressure. Over the last two decades, a wide variety of 3D printing technologies have been adapted to hard tissue and organ engineering. These 3D printing technologies have been defined as 3D bioprinting. Especially for hard organ regeneration, a series of new theories, strategies and protocols have been proposed. Some of the technologies have been applied in medical therapies with some successes. Each of the technologies has pros and cons in hard tissue and organ engineering. In this review, we summarize the advantages and disadvantages of the historical available innovative 3D bioprinting technologies for used as special tools for hard tissue and organ engineering.

  18. 3D Bioprinting Technologies for Hard Tissue and Organ Engineering.

    Science.gov (United States)

    Wang, Xiaohong; Ao, Qiang; Tian, Xiaohong; Fan, Jun; Wei, Yujun; Hou, Weijian; Tong, Hao; Bai, Shuling

    2016-09-27

    Hard tissues and organs, including the bones, teeth and cartilage, are the most extensively exploited and rapidly developed areas in regenerative medicine field. One prominent character of hard tissues and organs is that their extracellular matrices mineralize to withstand weight and pressure. Over the last two decades, a wide variety of 3D printing technologies have been adapted to hard tissue and organ engineering. These 3D printing technologies have been defined as 3D bioprinting. Especially for hard organ regeneration, a series of new theories, strategies and protocols have been proposed. Some of the technologies have been applied in medical therapies with some successes. Each of the technologies has pros and cons in hard tissue and organ engineering. In this review, we summarize the advantages and disadvantages of the historical available innovative 3D bioprinting technologies for used as special tools for hard tissue and organ engineering.

  19. Factorization and non-factorization in diffractive hard scattering

    International Nuclear Information System (INIS)

    Berera, Arjun

    1997-01-01

    Factorization, in the sense defined for inclusive hard scattering, is discussed for diffractive hard scattering. A factorization theorem similar to its inclusive counterpart is presented for diffractive DIS. For hadron-hadron diffractive hard scattering, in contrast to its inclusive counterpart, the expected breakdown of factorization is discussed. Cross section estimates are given from a simple field theory model for non-factorizing double-pomeron-exchange (DPE) dijet production with and without account for Sudakov suppression

  20. Development of Composite Grinding Wheels for Hard and Soft Metals

    OpenAIRE

    Pruti, Faruk

    2012-01-01

    This research investigates the performance of grinding wheel in terms of its internal granular particles and their effect on the surface finish for both soft and hard metals subjected to both dry and wet conditions of use. The study considers the properties of materials of construction including hardness of the granular particles and their size and distributions that affects the grinding wheel efficiency in abrading of soft and hard metal surfaces. Furthermore, in order to improve grinding pe...

  1. 3D Bioprinting Technologies for Hard Tissue and Organ Engineering

    OpenAIRE

    Wang, Xiaohong; Ao, Qiang; Tian, Xiaohong; Fan, Jun; Wei, Yujun; Hou, Weijian; Tong, Hao; Bai, Shuling

    2016-01-01

    Hard tissues and organs, including the bones, teeth and cartilage, are the most extensively exploited and rapidly developed areas in regenerative medicine field. One prominent character of hard tissues and organs is that their extracellular matrices mineralize to withstand weight and pressure. Over the last two decades, a wide variety of 3D printing technologies have been adapted to hard tissue and organ engineering. These 3D printing technologies have been defined as 3D bioprinting. Especial...

  2. Soft is hard and hard is easy: learning technologies and social media

    Directory of Open Access Journals (Sweden)

    Jon Dron

    2013-03-01

    Full Text Available Questo articolo riguarda principalmente la natura delle tecnologie per apprendere, con una particolare attenzione ai social media. Muovendo dalla definizione fornita da W. Brian Arthur delle tecnologie come un insieme di fenomeni orchestrati per un qualche uso, l’articolo amplia la teoria di Arthur ridefinendo e allargando la distinzione comunemente accettata tra tecnologie soft e hard, laddove le tecnologie soft sono intese come quelle che richiedono l’orchestrazione di fenomeni da parte degli esseri umani, mentre le tecnologie hard sono quelle per le quali l’orchestrazione è predeterminata o incorporata. Le tecnologie per apprendere sono quelle in cui le pedagogie (anch’esse tecnologie sono parte dell’insieme. Le conseguenze di questa prospettiva vengono esplorate nel quadro di diversi modelli pedagogici e in relazione agli approcci basati sul social learning in una varietà di contesti, dai corsi per corrispondenza ai MOOC.

  3. How to estimate hardness of crystals on a pocket calculator

    International Nuclear Information System (INIS)

    Simunek, Antonin

    2007-01-01

    A generalization of the semiempirical microscopic model of hardness is presented and applied to currently studied borides, carbides, and nitrides of heavy transition metals. The hardness of OsB, OsC, OsN, PtN, RuC, RuB 2 , ReB 2 , OsB 2 , IrN 2 , PtN 2 , and OsN 2 crystals in various structural phases is predicted. It is found that none of the transition metal crystals is superhard, i.e., with hardness greater than 40 GPa. The presented method provides materials researchers with a practical tool in the search for new hard materials

  4. Flour quality and kernel hardness connection in winter wheat

    Directory of Open Access Journals (Sweden)

    Szabó B. P.

    2016-12-01

    Full Text Available Kernel hardness is controlled by friabilin protein and it depends on the relation between protein matrix and starch granules. Friabilin is present in high concentration in soft grain varieties and in low concentration in hard grain varieties. The high gluten, hard wheat our generally contains about 12.0–13.0% crude protein under Mid-European conditions. The relationship between wheat protein content and kernel texture is usually positive and kernel texture influences the power consumption during milling. Hard-textured wheat grains require more grinding energy than soft-textured grains.

  5. Micro-hardness of non-irradiated uranium dioxide

    International Nuclear Information System (INIS)

    Kim, Sung-Sik; Takagi, Osamu; Obata, Naomi; Kirihara, Tomoo.

    1983-01-01

    In order to obtain the optimum conditions for micro-hardness measurements of sintered UO 2 , two kinds of hardness tests (Vickers and Knoop) were examined with non-irradiated UO 2 of 2.5 and 5 μm in grain size. The hardness values were obtained as a function of the applied load in the load range of 25 -- 1,000 g. In the Vickers test, cracks were generated around the periphery of an indentation even at lower load of 50 g, which means the Vickers hardness is not suitable for UO 2 specimens. In the Knoop test, three stages of load dependence were observed for sintered pellet as well as for a single crystal by Bates. Load dependence of Knoop hardness and crack formation were discussed. In the range of applied load around 70 -- 100 g there were plateau region where hardness values were nearly unchanged and did not contain any cracks in the indentation. The plateau region represents a hardness of a specimen. From a comparison between the hardness values of 2.5 μm and those of 5 μm UO 2 , it was approved that the degree of sintering controls the hardness in the plateau region. (author)

  6. Hard X-ray studies on the Castor tokamak

    International Nuclear Information System (INIS)

    Mlynar, J.

    1990-04-01

    The electron runaway processes in tokamaks are discussed with regard to hard X radiation measurements. The origin and confinement of runaway electrons, their bremsstrahlung spectra and the influence of lower hybrid current drive on the distribution of high-energy electrons are analyzed for the case of the Castor tokamak. The hard X-ray spectrometer designed for the Castor tokamak is also described and preliminary qualitative results of hard X-ray measurements are presented. The first series of integral measurements made it possible to map the azimuthal dependence of the hard X radiation

  7. Hard and soft acids and bases: structure and process.

    Science.gov (United States)

    Reed, James L

    2012-07-05

    Under investigation is the structure and process that gives rise to hard-soft behavior in simple anionic atomic bases. That for simple atomic bases the chemical hardness is expected to be the only extrinsic component of acid-base strength, has been substantiated in the current study. A thermochemically based operational scale of chemical hardness was used to identify the structure within anionic atomic bases that is responsible for chemical hardness. The base's responding electrons have been identified as the structure, and the relaxation that occurs during charge transfer has been identified as the process giving rise to hard-soft behavior. This is in contrast the commonly accepted explanations that attribute hard-soft behavior to varying degrees of electrostatic and covalent contributions to the acid-base interaction. The ability of the atomic ion's responding electrons to cause hard-soft behavior has been assessed by examining the correlation of the estimated relaxation energies of the responding electrons with the operational chemical hardness. It has been demonstrated that the responding electrons are able to give rise to hard-soft behavior in simple anionic bases.

  8. Hard metal lung disease: a case series.

    Science.gov (United States)

    Mizutani, Rafael Futoshi; Terra-Filho, Mário; Lima, Evelise; Freitas, Carolina Salim Gonçalves; Chate, Rodrigo Caruso; Kairalla, Ronaldo Adib; Carvalho-Oliveira, Regiani; Santos, Ubiratan Paula

    2016-01-01

    To describe diagnostic and treatment aspects of hard metal lung disease (HMLD) and to review the current literature on the topic. This was a retrospective study based on the medical records of patients treated at the Occupational Respiratory Diseases Clinic of the Instituto do Coração, in the city of São Paulo, Brazil, between 2010 and 2013. Of 320 patients treated during the study period, 5 (1.56%) were diagnosed with HMLD. All of those 5 patients were male (mean age, 42.0 ± 13.6 years; mean duration of exposure to hard metals, 11.4 ± 8.0 years). Occupational histories were taken, after which the patients underwent clinical evaluation, chest HRCT, pulmonary function tests, bronchoscopy, BAL, and lung biopsy. Restrictive lung disease was found in all subjects. The most common chest HRCT finding was ground glass opacities (in 80%). In 4 patients, BALF revealed multinucleated giant cells. In 3 patients, lung biopsy revealed giant cell interstitial pneumonia. One patient was diagnosed with desquamative interstitial pneumonia associated with cellular bronchiolitis, and another was diagnosed with a hypersensitivity pneumonitis pattern. All patients were withdrawn from exposure and treated with corticosteroid. Clinical improvement occurred in 2 patients, whereas the disease progressed in 3. Although HMLD is a rare entity, it should always be included in the differential diagnosis of respiratory dysfunction in workers with a high occupational risk of exposure to hard metal particles. A relevant history (clinical and occupational) accompanied by chest HRCT and BAL findings suggestive of the disease might be sufficient for the diagnosis. Descrever aspectos relacionados ao diagnóstico e tratamento de pacientes com doença pulmonar por metal duro (DPMD) e realizar uma revisão da literatura. Estudo retrospectivo dos prontuários médicos de pacientes atendidos no Serviço de Doenças Respiratórias Ocupacionais do Instituto do Coração, localizado na cidade de S

  9. Aespoe Hard Rock Laboratory. Annual report 1997

    International Nuclear Information System (INIS)

    1998-05-01

    The Aespoe Hard Rock Laboratory has been constructed as part of the preparations for the deep geological repository for spent nuclear fuel in Sweden. The surface and borehole investigations and the research work performed in parallel with construction have provided a thorough test of methods for investigation and evaluation of bedrock conditions for construction of a deep repository. The Tracer Retention Understanding Experiments are made to gain a better understanding of radionuclide retention in the rock and create confidence in the radionuclide transport models that are intended to be used in the licensing of a deep repository for spent fuel. The experimental results of the first tracer test with sorbing radioactive tracers have been obtained. These tests have been subject to blind predictions by the Aespoe Task Force on groundwater flow and transports of solutes. The manufacturing of the CHEMLAB probe was completed during 1996, and the first experiments were started early in 1997. During 1997 three experiments on diffusion in bentonite using 57 Co, 114 Cs, 85 Sr, 99 Tc, and 131 I were conducted. The Prototype Repository Test is focused on testing and demonstrating repository system function. A full scale prototype including six deposition holes with canisters with electric heaters surrounded by highly compacted bentonite will be built and instrumented. The characterization of the rock mass in the area of the prototype repository is in progress. The objectives of the Demonstration of Repository Technology are to develop, test, and demonstrate methodology and equipment for encapsulation and deposition of spent nuclear fuel. The demonstration of handling and deposition will be made in a new drift. The Backfill and Plug Test includes tests of backfill materials and emplacement methods and a test of a full scale plug. The backfill and rock will be instrumented with about 230 transducers for measuring the thermo-hydro-mechanical processes. The Retrieval Test is

  10. Aespoe Hard Rock Laboratory Annual Report 1999

    International Nuclear Information System (INIS)

    2000-08-01

    The Aespoe Hard Rock Laboratory has been constructed as part of the preparations for the deep geological repository for spent nuclear fuel in Sweden. The Tracer Retention Understanding Experiments are made to gain a better understanding of radionuclide retention in the rock and create confidence in the radionuclide transport models that are intended to be used in the licensing of a deep repository for spent fuel. The TRUE -1 experiment including tests with sorbing radioactive tracers in a single fracture over a distance of about 5 m has been completed. Diffusion and sorption in the rock matrix is the dominant retention mechanism over the time scales of the experiments. The main objective of the TRUE Block Scale Experiment is to increase understanding and our ability to predict tracer transport in a fracture network over spatial scales of 10 to 50 m. In total six boreholes have been drilled into the experimental volume located at the 450 m level. The Long-Term Diffusion Experiment is intended as a complement to the dynamic in-situ experiments and the laboratory experiments performed in the TRUE Programme. Diffusion from a fracture into the rock matrix will be studied in situ. The REX project focuses on the reduction of oxygen in a repository after closure due to reactions with rock minerals and microbial activity. Results show that oxygen is consumed within a few days both for the field and laboratory experiments. A new site for the CHEMLAB experiments was selected and prepared during 1999. All future experiment will be conducted in the J niche at 450 m depth. The Prototype Repository Test is focused on testing and demonstrating repository system function. A full-scale prototype including six deposition holes with canisters with electric heaters surrounded by highly compacted bentonite will be built and instrumented. Characterisation of the rock mass in the area of the Prototype repository is completed and the six deposition holes have been drilled. The Backfill and

  11. Non-hard sphere thermodynamic perturbation theory.

    Science.gov (United States)

    Zhou, Shiqi

    2011-08-21

    A non-hard sphere (HS) perturbation scheme, recently advanced by the present author, is elaborated for several technical matters, which are key mathematical details for implementation of the non-HS perturbation scheme in a coupling parameter expansion (CPE) thermodynamic perturbation framework. NVT-Monte Carlo simulation is carried out for a generalized Lennard-Jones (LJ) 2n-n potential to obtain routine thermodynamic quantities such as excess internal energy, pressure, excess chemical potential, excess Helmholtz free energy, and excess constant volume heat capacity. Then, these new simulation data, and available simulation data in literatures about a hard core attractive Yukawa fluid and a Sutherland fluid, are used to test the non-HS CPE 3rd-order thermodynamic perturbation theory (TPT) and give a comparison between the non-HS CPE 3rd-order TPT and other theoretical approaches. It is indicated that the non-HS CPE 3rd-order TPT is superior to other traditional TPT such as van der Waals/HS (vdW/HS), perturbation theory 2 (PT2)/HS, and vdW/Yukawa (vdW/Y) theory or analytical equation of state such as mean spherical approximation (MSA)-equation of state and is at least comparable to several currently the most accurate Ornstein-Zernike integral equation theories. It is discovered that three technical issues, i.e., opening up new bridge function approximation for the reference potential, choosing proper reference potential, and/or using proper thermodynamic route for calculation of f(ex-ref), chiefly decide the quality of the non-HS CPE TPT. Considering that the non-HS perturbation scheme applies for a wide variety of model fluids, and its implementation in the CPE thermodynamic perturbation framework is amenable to high-order truncation, the non-HS CPE 3rd-order or higher order TPT will be more promising once the above-mentioned three technological advances are established. © 2011 American Institute of Physics

  12. Aespoe Hard Rock Laboratory. Annual report 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-05-01

    The Aespoe Hard Rock Laboratory has been constructed as part of the preparations for the deep geological repository for spent nuclear fuel in Sweden. The surface and borehole investigations and the research work performed in parallel with construction have provided a thorough test of methods for investigation and evaluation of bedrock conditions for construction of a deep repository. The Tracer Retention Understanding Experiments are made to gain a better understanding of radionuclide retention in the rock and create confidence in the radionuclide transport models that are intended to be used in the licensing of a deep repository for spent fuel. The experimental results of the first tracer test with sorbing radioactive tracers have been obtained. These tests have been subject to blind predictions by the Aespoe Task Force on groundwater flow and transports of solutes. The manufacturing of the CHEMLAB probe was completed during 1996, and the first experiments were started early in 1997. During 1997 three experiments on diffusion in bentonite using {sup 57}Co, {sup 114}Cs,{sup 85}Sr, {sup 99}Tc, and {sup 131}I were conducted. The Prototype Repository Test is focused on testing and demonstrating repository system function. A full scale prototype including six deposition holes with canisters with electric heaters surrounded by highly compacted bentonite will be built and instrumented. The characterization of the rock mass in the area of the prototype repository is in progress. The objectives of the Demonstration of Repository Technology are to develop, test, and demonstrate methodology and equipment for encapsulation and deposition of spent nuclear fuel. The demonstration of handling and deposition will be made in a new drift. The Backfill and Plug Test includes tests of backfill materials and emplacement methods and a test of a full scale plug. The backfill and rock will be instrumented with about 230 transducers for measuring the thermo-hydro-mechanical processes. The

  13. Aespoe Hard Rock Laboratory Annual Report 1999

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-08-01

    The Aespoe Hard Rock Laboratory has been constructed as part of the preparations for the deep geological repository for spent nuclear fuel in Sweden. The Tracer Retention Understanding Experiments are made to gain a better understanding of radionuclide retention in the rock and create confidence in the radionuclide transport models that are intended to be used in the licensing of a deep repository for spent fuel. The TRUE -1 experiment including tests with sorbing radioactive tracers in a single fracture over a distance of about 5 m has been completed. Diffusion and sorption in the rock matrix is the dominant retention mechanism over the time scales of the experiments. The main objective of the TRUE Block Scale Experiment is to increase understanding and our ability to predict tracer transport in a fracture network over spatial scales of 10 to 50 m. In total six boreholes have been drilled into the experimental volume located at the 450 m level. The Long-Term Diffusion Experiment is intended as a complement to the dynamic in-situ experiments and the laboratory experiments performed in the TRUE Programme. Diffusion from a fracture into the rock matrix will be studied in situ. The REX project focuses on the reduction of oxygen in a repository after closure due to reactions with rock minerals and microbial activity. Results show that oxygen is consumed within a few days both for the field and laboratory experiments. A new site for the CHEMLAB experiments was selected and prepared during 1999. All future experiment will be conducted in the J niche at 450 m depth. The Prototype Repository Test is focused on testing and demonstrating repository system function. A full-scale prototype including six deposition holes with canisters with electric heaters surrounded by highly compacted bentonite will be built and instrumented. Characterisation of the rock mass in the area of the Prototype repository is completed and the six deposition holes have been drilled. The Backfill and

  14. Aespoe Hard Rock Laboratory Annual Report 1994

    International Nuclear Information System (INIS)

    1995-04-01

    The Aespoe Hard Rock Laboratory is being constructed as part of the preparations for the deep geological repository of spent nuclear fuel in Sweden. The annual report 1994 contains an overview of the work conducted. Present work is focused on verification of pre-investigation methods and development of detailed investigation methodology which is applied during tunnel construction. Construction of the facility and detailed characterization of the bedrock are performed in parallel. Excavation of the main access tunnel was completed during 1994 and at the end of the year only minor excavation work remained. The last 400 m of the main tunnel, which has a total length of 3600 m, was excavated by a 5 m diameter boring machine. The tunnel reaches a depth of 450 m below ground. Preparations for the operating phase have started and detailed plans have been prepared for several experiments. Nine organizations, including SKB, from eight countries are now participating in the work at the laboratory. 50 refs, 28 figs

  15. Aespoe Hard Rock Laboratory. Annual Report 2006

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-06-15

    The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. Aespoe HRL is located in the Simpevarp area in the municipality of Oskarshamn. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create opportunities for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its research, as well as in the development and demonstration tasks. The work performed at Aespoe HRL during 2006 is in this report described in six chapters: Geo-science - experiments, analysis and modelling to increase the knowledge of the surrounding rock; Natural barriers - experiments, analysis and modelling to increase the knowledge of the repository barriers under natural conditions; Engineered barriers - demonstration of technology for and function of important engineered parts of the repository barrier system; Aespoe facility - operation, maintenance, data management, monitoring, public relations etc; Environmental research; and finally, International co-operation.

  16. Unraveling Quantum Annealers using Classical Hardness

    Science.gov (United States)

    Martin-Mayor, Victor; Hen, Itay

    2015-01-01

    Recent advances in quantum technology have led to the development and manufacturing of experimental programmable quantum annealing optimizers that contain hundreds of quantum bits. These optimizers, commonly referred to as ‘D-Wave’ chips, promise to solve practical optimization problems potentially faster than conventional ‘classical’ computers. Attempts to quantify the quantum nature of these chips have been met with both excitement and skepticism but have also brought up numerous fundamental questions pertaining to the distinguishability of experimental quantum annealers from their classical thermal counterparts. Inspired by recent results in spin-glass theory that recognize ‘temperature chaos’ as the underlying mechanism responsible for the computational intractability of hard optimization problems, we devise a general method to quantify the performance of quantum annealers on optimization problems suffering from varying degrees of temperature chaos: A superior performance of quantum annealers over classical algorithms on these may allude to the role that quantum effects play in providing speedup. We utilize our method to experimentally study the D-Wave Two chip on different temperature-chaotic problems and find, surprisingly, that its performance scales unfavorably as compared to several analogous classical algorithms. We detect, quantify and discuss several purely classical effects that possibly mask the quantum behavior of the chip. PMID:26483257

  17. Computational Modeling Develops Ultra-Hard Steel

    Science.gov (United States)

    2007-01-01

    Glenn Research Center's Mechanical Components Branch developed a spiral bevel or face gear test rig for testing thermal behavior, surface fatigue, strain, vibration, and noise; a full-scale, 500-horsepower helicopter main-rotor transmission testing stand; a gear rig that allows fundamental studies of the dynamic behavior of gear systems and gear noise; and a high-speed helical gear test for analyzing thermal behavior for rotorcraft. The test rig provides accelerated fatigue life testing for standard spur gears at speeds of up to 10,000 rotations per minute. The test rig enables engineers to investigate the effects of materials, heat treat, shot peen, lubricants, and other factors on the gear's performance. QuesTek Innovations LLC, based in Evanston, Illinois, recently developed a carburized, martensitic gear steel with an ultra-hard case using its computational design methodology, but needed to verify surface fatigue, lifecycle performance, and overall reliability. The Battelle Memorial Institute introduced the company to researchers at Glenn's Mechanical Components Branch and facilitated a partnership allowing researchers at the NASA Center to conduct spur gear fatigue testing for the company. Testing revealed that QuesTek's gear steel outperforms the current state-of-the-art alloys used for aviation gears in contact fatigue by almost 300 percent. With the confidence and credibility provided by the NASA testing, QuesTek is commercializing two new steel alloys. Uses for this new class of steel are limitless in areas that demand exceptional strength for high throughput applications.

  18. Exotic hybrid mesons in hard electroproduction

    CERN Document Server

    Anikin, I V; Szymanowski, L; Teryaev, O V; Wallon, S

    2005-01-01

    We estimate the sizeable cross section for deep exclusive electroproduction of an exotic $J^{PC}=1^{-+}$ hybrid meson in the Bjorken regime. The production amplitude scales like the one for usual meson electroproduction, i.e. as $1/Q^2$. This is due to the non-vanishing leading twist distribution amplitude for the hybrid meson, which may be normalized thanks to its relation to the energy momentum tensor and to the QCD sum rules technique. The hard amplitude is considered up to next-to-leading order in $\\alpha_{S}$ and we explore the consequences of fixing the renormalization scale ambiguity through the BLM procedure. We study the particular case where the hybrid meson decays through a $\\pi\\eta $ meson pair. We discuss the $\\pi\\eta$ generalized distribution amplitude and then calculate the production amplitude for this process. We propose a forward-backward asymmetry in the production of $\\pi$ and $\\eta$ mesons as a signal for the hybrid meson production. We briefly comment on hybrid electroproduction at very ...

  19. From hard thermal loops to Langevin dynamics

    International Nuclear Information System (INIS)

    Boedeker, Dietrich

    1999-01-01

    In hot non-Abelian gauge theories, processes characterized by the momentum scale g 2 T (such as electroweak baryon number violation in the very early universe) are non-perturbative. An effective theory for the soft (vertical bar p vertical bar ∼ g 2 T) field modes is obtained by integrating out momenta larger than than g 2 T. Starting from the hard thermal loop effective theory, which is the result of integrating out the scale T, it is shown how to integrate out the scale gT in an expansion in the gauge coupling g. At leading order in g, one obtains Vlasov-Boltzmann equations for the soft field modes, which contain a Gaussian noise and a collision term. The 2-point function of the noise and the collision term are explicitly calculated in a leading logarithmic approximation. In this approximation the Boltzmann equation is solved. The resulting effective theory for the soft field modes is described by a Langevin equation. It determines the parametric form of the hot baryon number violation rate as Γ = κg 10 log(1/g)gT 4 , and it allows for a calculation for κ on the lattice

  20. Integrated Planning: Why is it so hard?

    International Nuclear Information System (INIS)

    Hesser, A.

    1994-01-01

    In this paper, the Manager of Planning integration at DOE-Richland and the Program Manager for Hanford Mission Planning at Pacific Northwest Laboratory and Westinghouse Hanford Company describe some of the reasons why integrated planning is so hard and what can be done to correct the situation. The authors use experiences from the last three years at Hanford to illustrate some of the difficulties in site integrated planning. The authors argue that integrated planning was not a major part of the previous diverse Site missions, but the change of mission has not resulted in a corresponding change of attitude about the need for such planning. Moreover, the DOE-RL staff is not structured or manned for planning, and a site perspective is the exception, rather than the norm. Contributing to this situation is the compartmentalization of funding and decision making and the diffusion of responsibility. The decision-making process at DOE sites is often not clear because of the evolving role of stakeholders, and agencies outside the DOE, especially regulators, are co-decision makers. The regulatory process and the requirements of environmental impact statements contribute to the diffusion of authority

  1. Hard X ray lines from neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Polcaro, V.F.; Bazzano, A.; La Padula, C.; Ubertini, P.

    1982-01-01

    Experimental evidence is presented and evaluated concerning the features of the hard X-ray spectra detected in a number of cosmic X-ray sources which contain a neutron star. The strong emission line at cyclotron resonance detected in the spectrum of Her XI at an energy of 58 keV is evaluated and the implications of this finding are discussed. Also examined is the presence of spectral features in the energy range 20-80 keV found in the spectra of gamma-ray bursts, which have been interpreted as cyclotron resonance from interstellar-gas-accreting neutron stars. The less understood finding of a variable emission line at approximately 70 keV in the spectrum of the Crab Pulsar is considered. It is determined that several features varying with time are present in the spectra of cosmic X-ray sources associated with neutron stars. If these features are due to cyclotron resonance, it is suggested that they provide a direct measurement of neutron star magnetic fields on the order of 10 to the 11th-10 to the 13th Gauss. However, the physical condition of the emitting region and its geometry are still quite obscure.

  2. Aespoe Hard Rock Laboratory. Annual Report 2006

    International Nuclear Information System (INIS)

    2006-06-01

    The Aespoe Hard Rock Laboratory (HRL) is an important part of SKB's work with the design and construction of a deep geological repository for the final disposal of spent nuclear fuel. Aespoe HRL is located in the Simpevarp area in the municipality of Oskarshamn. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create opportunities for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. The underground part of the laboratory consists of a tunnel from the Simpevarp peninsula to the southern part of Aespoe where the tunnel continues in a spiral down to a depth of 460 m. Aespoe HRL has been in operation since 1995 and considerable international interest has been shown in its research, as well as in the development and demonstration tasks. The work performed at Aespoe HRL during 2006 is in this report described in six chapters: Geo-science - experiments, analysis and modelling to increase the knowledge of the surrounding rock; Natural barriers - experiments, analysis and modelling to increase the knowledge of the repository barriers under natural conditions; Engineered barriers - demonstration of technology for and function of important engineered parts of the repository barrier system; Aespoe facility - operation, maintenance, data management, monitoring, public relations etc; Environmental research; and finally, International co-operation

  3. Aespoe Hard Rock Laboratory Annual report 2003

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-09-01

    The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a deep geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site for a deep repository. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create an opportunity for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. Aespoe HRL has been in operation since 1995 and the associated research, development, and demonstration tasks, have so far attracted considerable interest. A summary of work performed at Aespoe HRL during 2003 is given below. Seven organisations from six countries participated in the co-operation at Aespoe HRL during 2003 in addition to SKB. Most of the organisations are interested in groundwater flow, radionuclide transport and rock characterisation. Several of the organisations are participating in the experimental work as well as in the Aespoe Task Force on Modelling of Groundwater Flow and Transport of Solutes. SKB is through Repository Technology co-ordinating three EC contracts and takes part in several EC projects of which the representation in five projects is channelled through Repository Technology. SKB takes also part in work within the IAEA framework.

  4. Traumatic Foot Fractures in Hard Working Donkeys

    Directory of Open Access Journals (Sweden)

    M.A. Semieka

    2012-10-01

    Full Text Available The present study was carried out on 45 hard working donkeys suffering from different types of traumatic foot fractures. These animals were selected from the clinical cases admitted to the Veterinary Teaching Hospital, Assiut University during the period of 2007-2010. Based on history, clinical signs and radiographic examination, various types of traumatic foot fractures were diagnosed and recorded. These fractures were affect metacarpal bones (N. =16, metatarsal bones (N. =9, proximal phalanx (N. = 13, middle phalanx (N. = 3, distal phalanx (N. = 2 and proximal sesamoid bones (N. = 2. It could be concluded that fractures of the large metacarpal bones are the most common types followed by fractures of the proximal phalanx of the thoracic limb then fractures of the metatarsal bones. Fractures of the middle phalanx, distal phalanx and proximal sesamoid bone are less common in donkeys. Single fractures of the metacarpal and metatarsal bones are more common than comminuted one, in addition diaphyseal fractures of these bones are more common than metaphyseal or epiphyseal fractures. In the proximal phalanx, comminuted fractures are more common than single fractures.

  5. Hard X-ray photoemission spectroscopy

    International Nuclear Information System (INIS)

    Kobayashi, Keisuke

    2009-01-01

    Except in the very early stage of the development of X-ray photoemission spectroscopy (XPS) by Kai Siegbahn and his coworkers, the excitation sources for XPS studies have predominantly been the Al Kα and Mg Kα emission lines. The advent of synchrotron radiation sources opened up the possibility of tuning the excitation photon energy with much higher throughputs for photoemission spectroscopy, however the excitation energy range was limited to the vacuum ultra violet and soft X-ray regions. Over the past 5-6 years, bulk-sensitive hard X-ray photoemission spectroscopy using high-brilliance high-flux X-rays from third generation synchrotron radiation facilities has been developed. This article reviews the history of HXPES covering the period from Kai Siegbahn and his coworkers' pioneering works to the present, and describes the fundamental aspects, instrumentation, applications to solid state physics, applied physics, materials science, and industrial applications of HXPES. Finally, several challenging new developments which have been conducted at SPring-8 by collaborations among several groups are introduced.

  6. Hazards of the 'hard cash': hypersensitivity pneumonitis.

    Science.gov (United States)

    Kupeli, Elif; Karnak, Demet; Sak, Serpil Dizbay; Kayacan, Oya

    2010-01-01

    Hypersensitivity pneumonitis (HP) is a nonimmunoglobulin E-related immune-mediated parenchymal lung disease. A 45-year-old woman who was a lifelong nonsmoker with a six-month history of frequent episodes of cough and dyspnea was admitted to hospital. She had been working as a money counter for 20 years at a central bank. Bibasilar crackles on lung auscultation, ground-glass opacities and a mosaic pattern on high-resolution computed tomography, restrictive abnormality on pulmonary function tests and mild hypoxemia were the prominent findings. Bronchoalveolar lavage fluid analysis revealed a predominance of CD4-positive T cells, and she tested positive on her natural challenge test. She was diagnosed with subacute HP based on established criteria. She was advised to discontinue counting fresh banknotes. Prednisolone was commenced, then tapered to discontinue in the ensuing six months. Clinical and radiological improvement was achieved within two months. To the authors' knowledge, the present report is the first to describe 'hard cash HP', possibly caused by chipping dust or printing dye.

  7. Radiation hardness of CMS pixel barrel modules

    CERN Document Server

    Rohe, T; Erdmann, W; Kästli, H C; Khalatyan, S; Meier, B; Radicci, V; Sibille, J

    2010-01-01

    Pixel detectors are used in the innermost part of the multi purpose experiments at LHC and are therefore exposed to the highest fluences of ionising radiation, which in this part of the detectors consists mainly of charged pions. The radiation hardness of all detector components has thoroughly been tested up to the fluences expected at the LHC. In case of an LHC upgrade, the fluence will be much higher and it is not yet clear how long the present pixel modules will stay operative in such a harsh environment. The aim of this study was to establish such a limit as a benchmark for other possible detector concepts considered for the upgrade. As the sensors and the readout chip are the parts most sensitive to radiation damage, samples consisting of a small pixel sensor bump-bonded to a CMS-readout chip (PSI46V2.1) have been irradiated with positive 200 MeV pions at PSI up to 6E14 Neq and with 21 GeV protons at CERN up to 5E15 Neq. After irradiation the response of the system to beta particles from a Sr-90 source w...

  8. Aespoe Hard Rock Laboratory Annual Report 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-04-01

    The Aespoe Hard Rock Laboratory is being constructed as part of the preparations for the deep geological repository of spent nuclear fuel in Sweden. The annual report 1994 contains an overview of the work conducted. Present work is focused on verification of pre-investigation methods and development of detailed investigation methodology which is applied during tunnel construction. Construction of the facility and detailed characterization of the bedrock are performed in parallel. Excavation of the main access tunnel was completed during 1994 and at the end of the year only minor excavation work remained. The last 400 m of the main tunnel, which has a total length of 3600 m, was excavated by a 5 m diameter boring machine. The tunnel reaches a depth of 450 m below ground. Preparations for the operating phase have started and detailed plans have been prepared for several experiments. Nine organizations, including SKB, from eight countries are now participating in the work at the laboratory. 50 refs, 28 figs.

  9. Aespoe Hard Rock Laboratory Annual report 2003

    International Nuclear Information System (INIS)

    2004-09-01

    The Aespoe Hard Rock Laboratory (HRL) constitutes an important part of SKB's work to design and construct a deep geological repository for spent nuclear fuel and to develop and test methods for characterisation of a suitable site for a deep repository. One of the fundamental reasons behind SKB's decision to construct an underground laboratory was to create an opportunity for research, development and demonstration in a realistic and undisturbed rock environment down to repository depth. Aespoe HRL has been in operation since 1995 and the associated research, development, and demonstration tasks, have so far attracted considerable interest. A summary of work performed at Aespoe HRL during 2003 is given below. Seven organisations from six countries participated in the co-operation at Aespoe HRL during 2003 in addition to SKB. Most of the organisations are interested in groundwater flow, radionuclide transport and rock characterisation. Several of the organisations are participating in the experimental work as well as in the Aespoe Task Force on Modelling of Groundwater Flow and Transport of Solutes. SKB is through Repository Technology co-ordinating three EC contracts and takes part in several EC projects of which the representation in five projects is channelled through Repository Technology. SKB takes also part in work within the IAEA framework

  10. Vapour-liquid equilibria of the hard core Yukawa fluid

    NARCIS (Netherlands)

    Smit, B.; Frenkel, D.

    1991-01-01

    Techniques which extend the range of applicability of the Gibbs ensemble technique for particles which interact with a hard core potential are described. The power of the new technique is demonstrated in a numerical study of the vapour-liquid coexistence curve of the hard core Yukawa fluid.

  11. Failure analysis and shock protection of external hard disk drive ...

    African Journals Online (AJOL)

    Technology for processing and storage of data in portable external storage hard disks has increasingly improved over the years. Currently, terabytes of data can be stored in one portable external storage hard disk drive. Storing such amount of data on a single disk on itself is a risk. Several instances of data lost by big ...

  12. Hard gap in epitaxial semiconductor-superconductor nanowires

    DEFF Research Database (Denmark)

    Chang, W.; Albrecht, S. M.; Jespersen, T. S.

    2015-01-01

    a continuum of subgap states---a situation that nullifies topological protection. Here, we report a hard superconducting gap induced by proximity effect in a semiconductor, using epitaxial Al-InAs superconductor-semiconductor nanowires. The hard gap, along with favorable material properties and gate...

  13. Hard facings used in welded joints. Industrial applications

    International Nuclear Information System (INIS)

    Delair, J.

    1998-01-01

    In this article, two industrial application cases of special hard facings used in offshore and nuclear fabrications are described into details. These hard facings concern more particularly 1)the heterogeneous joints of a martensitic steel on an ordinary carbon steel 2)the homogeneous joints of a high resistive low alloy carbon steel. (O.M.)

  14. Car sequencing is NP-hard: a short proof

    OpenAIRE

    B Estellon; F Gardi

    2013-01-01

    In this note, a new proof is given that the car sequencing (CS) problem is NP-hard. Established from the Hamiltonian Path problem, the reduction is direct while closing some gaps remaining in the previous NP-hardness results. Since CS is studied in many operational research courses, this result and its proof are particularly interesting for teaching purposes.

  15. Wheat Quality Council, Hard Spring Wheat Technical Committee, 2017 Crop

    Science.gov (United States)

    Nine experimental lines of hard spring wheat were grown at up to six locations in 2017 and evaluated for kernel, milling, and bread baking quality against the check variety Glenn. Wheat samples were submitted through the Wheat Quality Council and processed and milled at the USDA-ARS Hard Red Spring...

  16. Adaptation policy in hard coal mining. Die Anpassungspolitik im Steinkohlenbergbau

    Energy Technology Data Exchange (ETDEWEB)

    Brink, H J; Haas, H; Jochum, E; Muellendorff, R; Rolshoven, H

    1981-01-01

    The book points out the necessity of balancing the output of hard coal mines. Detailed analyses of marketing conditions serve as a decision aid for business policy. Production and sales trends in German hard coal mining, instruments of adaptation to quantitative changes in sales, and empirical investigations of adaptation instruments in the underground part of the Goettelborn mine are reviewed.

  17. failure analysis and shock protection of external hard disk drive

    African Journals Online (AJOL)

    user

    model its structural responses to free fall drop-impact shock and vibration. Secondly, the hard ... Keywords: Free fall, impact force, Shock, Vibration, Stress, Reliability, Modeling, Simulation External Hard disk drive. 1. ..... on the disk, it could initiate process which could .... [19] Katta, P.: MATLAB Guide to Finite Elements - An.

  18. Thermodynamics and vibrational modes of hard sphere colloidal systems

    NARCIS (Netherlands)

    Zargar, R.

    2014-01-01

    The central question that we address in this thesis is the thermodynamics of colloidal glasses. The thermodynamics of colloidal hard sphere glasses are directly related to the entropy of the system, since the phase behavior of hard sphere systems is dictated only by entropic contributions, and also

  19. Influence of skin hardness on dehydration kinetics of wine grapes.

    Science.gov (United States)

    Rolle, Luca; Caudana, Alberto; Giacosa, Simone; Gerbi, Vincenzo; Río Segade, Susana

    2011-02-01

    Knowledge of the influence of initial mechanical properties on the evolution of the weight loss of berries through the drying process is scarce. Therefore, the main purpose of this work was to investigate the effect of skin hardness at two different physiological stages of off-vine drying kinetics of grapes. Skin hardness was evaluated as the berry skin-break force parameter, measured by the texture analysis test. The decrease of berry weight as a function of the drying time was linear, indicating that the drying rates were constant within each cultivar studied (Moscato bianco and Erbaluce), and for each ripening stage and berry skin hardness. The drying rates decreased as berry skin hardness increased for the ripest grapes in the cultivars studied. The study allowed the assessment of the correlation between the skin hardness of fresh berries and the weight loss determined for different drying days. 2010 Society of Chemical Industry.

  20. A new, bright and hard aluminum surface produced by anodization

    Science.gov (United States)

    Hou, Fengyan; Hu, Bo; Tay, See Leng; Wang, Yuxin; Xiong, Chao; Gao, Wei

    2017-07-01

    Anodized aluminum (Al) and Al alloys have a wide range of applications. However, certain anodized finishings have relatively low hardness, dull appearance and/or poor corrosion resistance, which limited their applications. In this research, Al was first electropolished in a phosphoric acid-based solution, then anodized in a sulfuric acid-based solution under controlled processing parameters. The anodized specimen was then sealed by two-step sealing method. A systematic study including microstructure, surface morphology, hardness and corrosion resistance of these anodized films has been conducted. Results show that the hardness of this new anodized film was increased by a factor of 10 compared with the pure Al metal. Salt spray corrosion testing also demonstrated the greatly improved corrosion resistance. Unlike the traditional hard anodized Al which presents a dull-colored surface, this newly developed anodized Al alloy possesses a very bright and shiny surface with good hardness and corrosion resistance.

  1. Particle production at large transverse momentum and hard collision models

    International Nuclear Information System (INIS)

    Ranft, G.; Ranft, J.

    1977-04-01

    The majority of the presently available experimental data is consistent with hard scattering models. Therefore the hard scattering model seems to be well established. There is good evidence for jets in large transverse momentum reactions as predicted by these models. The overall picture is however not yet well enough understood. We mention only the empirical hard scattering cross section introduced in most of the models, the lack of a deep theoretical understanding of the interplay between quark confinement and jet production, and the fact that we are not yet able to discriminate conclusively between the many proposed hard scattering models. The status of different hard collision models discussed in this paper is summarized. (author)

  2. Sampling from a polytope and hard-disk Monte Carlo

    International Nuclear Information System (INIS)

    Kapfer, Sebastian C; Krauth, Werner

    2013-01-01

    The hard-disk problem, the statics and the dynamics of equal two-dimensional hard spheres in a periodic box, has had a profound influence on statistical and computational physics. Markov-chain Monte Carlo and molecular dynamics were first discussed for this model. Here we reformulate hard-disk Monte Carlo algorithms in terms of another classic problem, namely the sampling from a polytope. Local Markov-chain Monte Carlo, as proposed by Metropolis et al. in 1953, appears as a sequence of random walks in high-dimensional polytopes, while the moves of the more powerful event-chain algorithm correspond to molecular dynamics evolution. We determine the convergence properties of Monte Carlo methods in a special invariant polytope associated with hard-disk configurations, and the implications for convergence of hard-disk sampling. Finally, we discuss parallelization strategies for event-chain Monte Carlo and present results for a multicore implementation

  3. Synthesis, Structure, and Properties of Refractory Hard-Metal Borides

    Science.gov (United States)

    Lech, Andrew Thomas

    As the limits of what can be achieved with conventional hard compounds, such as tungsten carbide, are nearing reach, super-hard materials are an area of increasing industrial interest. The refractory hard metal borides, such as ReB2 and WB4, offer an increasingly attractive alternative to diamond and cubic boron nitride as a next-generation tool material. In this Thesis, a thorough discussion is made of the progress achieved by our laboratory towards understanding the synthesis, structure, and properties of these extremely hard compounds. Particular emphasis is placed on structural manipulation, solid solution formation, and the unique crystallographic manifestations of what might also be called "super-hard metals".

  4. Aespoe Hard Rock Laboratory. Annual report 1998

    International Nuclear Information System (INIS)

    1999-05-01

    The Aespoe Hard Rock Laboratory has been constructed as part of the preparations for the deep geological repository for spent nuclear fuel in Sweden. The Tracer Retention Understanding Experiments are made to gain a better understanding of radionuclide retention in the rock and create confidence in the radionuclide transport models that are intended to be used in the licensing of a deep repository for spent fuel. Experiments with sorbing radioactive tracers have been completed in a single fracture over a distance of about 5 m. These tests have been subject to blind predictions by the Aespoe Task Force on groundwater flow and transports of solutes. Breakthrough of sorbing tracers in the TRUE-I tests is retarded more strongly than would be expected based on laboratory data alone. Results are consistent for all tracers and tracer tests. The main objective of the TRUE Block Scale Experiment is to increase understanding and our ability to predict tracer transport in a fracture network over spatial scales of 10 to 50 m. The total duration of the project is approximately 4.5 years with a scheduled finish at the end of the year 2000. The REX project focuses on the reduction of oxygen in a repository after closure due to reactions with rock minerals and microbial activity. Results show that oxygen is consumed within a few days both for the field and laboratory experiments. The project Degassing of groundwater and two phase flow was initiated to improve our understanding of observations of hydraulic conditions made in drifts and interpretation of experiments performed close to drifts. The analysis performed so far shows that the experimentally observed flow reductions indeed are consistent with the degassing hypothesis. The Prototype Repository Test is focused on testing and demonstrating repository system function. A full-scale prototype including six deposition holes with canisters with electric heaters surrounded by highly compacted bentonite will be built and

  5. Aespoe Hard Rock Laboratory. Annual report 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-05-01

    The Aespoe Hard Rock Laboratory has been constructed as part of the preparations for the deep geological repository for spent nuclear fuel in Sweden. The Tracer Retention Understanding Experiments are made to gain a better understanding of radionuclide retention in the rock and create confidence in the radionuclide transport models that are intended to be used in the licensing of a deep repository for spent fuel. Experiments with sorbing radioactive tracers have been completed in a single fracture over a distance of about 5 m. These tests have been subject to blind predictions by the Aespoe Task Force on groundwater flow and transports of solutes. Breakthrough of sorbing tracers in the TRUE-I tests is retarded more strongly than would be expected based on laboratory data alone. Results are consistent for all tracers and tracer tests. The main objective of the TRUE Block Scale Experiment is to increase understanding and our ability to predict tracer transport in a fracture network over spatial scales of 10 to 50 m. The total duration of the project is approximately 4.5 years with a scheduled finish at the end of the year 2000. The REX project focuses on the reduction of oxygen in a repository after closure due to reactions with rock minerals and microbial activity. Results show that oxygen is consumed within a few days both for the field and laboratory experiments. The project Degassing of groundwater and two phase flow was initiated to improve our understanding of observations of hydraulic conditions made in drifts and interpretation of experiments performed close to drifts. The analysis performed so far shows that the experimentally observed flow reductions indeed are consistent with the degassing hypothesis. The Prototype Repository Test is focused on testing and demonstrating repository system function. A full-scale prototype including six deposition holes with canisters with electric heaters surrounded by highly compacted bentonite will be built and

  6. Radiation hardness of CMS pixel barrel modules

    International Nuclear Information System (INIS)

    Rohe, T.; Bean, A.; Erdmann, W.; Kaestli, H.-C.; Khalatyan, S.; Meier, B.; Radicci, V.; Sibille, J.

    2010-01-01

    Pixel detectors are used in the innermost part of the multi purpose experiments at the LHC and are therefore exposed to the highest fluences of ionising radiation, which in this part of the detectors consists mainly of charged pions. The radiation hardness of all detector components has been thoroughly tested up to the fluences expected at the LHC. In case of an LHC upgrade, the fluence will be much higher and it is not yet clear how long the present pixel modules will stay operative in such a harsh environment. The aim of this study was to establish such a limit as a benchmark for other possible detector concepts considered for the upgrade. As the sensors and the readout chip are the parts most sensitive to radiation damage, samples consisting of a small pixel sensor bump-bonded to a CMS-readout chip (PSI46V2.1) have been irradiated with positive 200 MeV pions at PSI up to 6x10 14 n eq /cm 2 and with 21 GeV protons at CERN up to 5x10 15 n eq /cm 2 . After irradiation the response of the system to beta particles from a 90 Sr source was measured to characterise the charge collection efficiency of the sensor. Radiation induced changes in the readout chip were also measured. The results show that the present pixel modules can be expected to be still operational after a fluence of 2.8x10 15 n eq /cm 2 . Samples irradiated up to 5x10 15 n eq /cm 2 still see the beta particles. However, further tests are needed to confirm whether a stable operation with high particle detection efficiency is possible after such a high fluence.

  7. Ethiopia: hard work for successful AIDS prevention.

    Science.gov (United States)

    1992-01-01

    An innovative AIDS control program targeting sex workers and clients in Ethiopia has shown that hard work and government support are essential for the success of a program. Serosurveys conducted in 1988 and 1989 had shown that certain groups were particularly vulnerable to HIV infection: women who engage in formal or informal prostitution and their clients -- often migrant workers or truck drivers. So in mid-1990, Ethiopia's Department of AIDS Control (DAC) launched an intervention effort targeting these high-risk groups, a program entitled the Multiple Partner Sexual Contact (MPSC) Female and Male Mobilization and Condom Promotion Project. The program had a 3-layer strategy: 1) establishing a "trickle down" training process, which would create a network of MPSC peer educators and organizers; 2) identifying MPSC men to serve as educators for other men; and 3) ensuring the widespread availability of condoms for both men and women. As site for its pilot project, DAC selected Nazareth, a trading city of more than 30% among MPSC females. After 6 months of operation, the program's effectiveness convinced DAC to expand the project to 9 additional sites. An evaluation of the project has revealed several important findings: 1) retraining and motivation sessions must be constantly maintained; 2) men's resistance to condom use may be diminished by targeting them with education at the same time as the women; 3) interventions that take into account the socioeconomic issues faced by MPSC women make the program more effective; 4) it is important to develop new educational materials periodically; and 5) involving the owners and managers of sex-related businesses makes the program more effective.

  8. Converting hard copy documents for electronic dissemination

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, F.

    1994-12-31

    Since the advent of computer systems, the goal of a paperless office, and even a paperless society, has been pursued. While the normal paper flow in an organization is far from totally automated, particularly for items requiring signatures or authorizations, electronic information dissemination is becoming an almost simple task. The reasons for providing on-line documents are many and include faster and easier access for everyone, elimination of printing costs, reduction of wasted shelf and desk space, and the security of having a centrally-located, always up-to-date document. New computer software even provides the user with the ability to annotate documents and to have bookmarks so that the old scribbled-in and dog-eared manual can be replaced without loosing this `customizability`. Moreover, new hypermedia capabilities mean that documents can be read in a non-linear fashion and can include color figures and photographs, audio, and even animation sequences, capabilities which exceed those of paper. The proliferation of network-based information servers, coupled with the growth of the Internet, has enticed academic, governmental, and even commercial organizations to provide increasing numbers of documents and data bases in electronic form via the network, not just to internal staff, but to the public as well. Much of this information, which includes everything from mundane company procedures to spiffy marketing brochures, was previously published only in hard copy. Converting existing documents to electronic form and producing only electronic versions of new documents poses some interesting challenges to the maintainer or author.

  9. Future Hard Disk Storage: Limits & Potential Solutions

    Science.gov (United States)

    Lambeth, David N.

    2000-03-01

    For several years the hard disk drive technology pace has raced along at 60-100products this year and laboratory demonstrations approaching what has been estimated as a physical thermal stability limit of around 40 Gbit/in2. For sometime now the data storage industry has recogniz d that doing business as usually will not be viable for long and so both incremental evolutionary and revolutionary technologies are being explored. While new recording head materials or thermal recording techniques may allow higher coercivity materials to be recorded upon, and while high sensitivity spin transport transducer technology may provide sufficient signals to extend beyond the 100 Gigabit/in2 regime, conventional isotropic longitudinal media will show large data retention problems at less than 1/2 of this value. We have recently developed a simple model which indicates that while thermal instability issues may appear at different areal densities, they are non-discriminatory as to the magnetic recording modality: longitudinal, perpendicular, magnetooptic, near field, etc. The model indicates that a strong orientation of the media tends to abate the onset of the thermal limit. Hence, for the past few years we have taken an approach of controlled growth of the microstructure of thin film media. This knowledge has lead us to believe that epitaxial growth of multiple thin film layers on single crystalline Si may provide a pathway to nearly perfect crystallites of various, highly oriented, thin film textures. Here we provide an overview of the recording system media challenges, which are useful for the development of a future media design philosophy and then discuss materials issues and processing techniques for multi-layered thin film material structures which may be used to achieve media structures which can easy exceed the limits predicted for isotropic media.

  10. Orientational Ordering and Phase Behaviour of Binary Mixtures of Hard Spheres and Hard Spherocylinders.

    Czech Academy of Sciences Publication Activity Database

    Wu, L.; Malijevský, Alexandr; Jackson, G.; Muller, E.A.; Avendano, C.

    2015-01-01

    Roč. 143, č. 4 (2015), s. 044906 ISSN 0021-9606 R&D Projects: GA ČR(CZ) GA13-02938S Grant - others:EPSRC(GB) GR/T17595; EPSRC(GB) GR/N35991; EPSRC(GB) EP/E016340; EPSRC(GB) EP/J014958; JREI(GB) GR/M94426 Institutional support: RVO:67985858 Keywords : phase behaviour * liquid crystals * hard spheres Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.894, year: 2015

  11. Specific Energy of Hard Coal Under Load

    Directory of Open Access Journals (Sweden)

    Bogusz Anna

    2015-03-01

    Full Text Available The article presents results of experimental tests of energy parameters of hard coals under loading, collected from research sites located within five main geologic structures of Upper Silesian Coal Basin (GZW - Main Trough, Main Anticline, Bytom Trough, Rybnik Trough and Chwałowice Trough. Coals from12 mines were analysed, starting with seams of group 200, through groups 400, 500, 600 and, finally, seams of group 700. Coal of each of the groups of seams underwent uniaxial compression stress of the energy parameters, in a servo-controlled testing machine MTS-810NEW, for the full range of strain of the tested coal samples. Based on the tests the dependence of different types of specific energy of longitudinal strain of coals on the value of uniaxial compression strength was determined. The dependence of the value of dissipated energy and kinetic energy of coals on the uniaxial compression strength was described with a linear function, both for coals which due to their age belong to various bed sand for various lithotypes of coal. An increase in the value of dissipated energy and in kinetic energy was observed, which was correlated with an increase in uniaxial compression strength of coal. The share of dissipated energy is dominant in the total energy of strain. Share of recoverable energy in the total energy of strain is small, independent of the compression strength of coals and is at most a few per cent high. In coals of low strength and dominant share of dissipated energy, share of recoverable energy is the biggest among the tested coals. It was shown that following an increase in compression strength the share of recoverable energy decreases, while the share of dissipated energy in the total energy increases. Further studies of specific energy of longitudinal strain of rocks in the full-range strain will be the next step inperfecting methodology of research into natural rock burst susceptibility of Carboniferous rock mass and changes in the

  12. Analysis of surface hardness of artificially aged resin composites

    Directory of Open Access Journals (Sweden)

    Denise Cremonezzi Tornavoi

    2012-02-01

    Full Text Available This study evaluated the effect of artificially accelerated aging (AAA on the surface hardness of eight composite resins: Filtek Z250, Filtek Supreme, 4 Seasons, Herculite, P60, Tetric Ceram, Charisma, and Filtek Z100. Sixteen specimens were made from the test piece of each material, using an 8.0 × 2.0 mm teflon matrix. After 24 hours, eight specimens from each material were submitted to three surface hardness readings using a Shimadzu Microhardness Tester for 5 seconds at a load of 50 gf. The other eight specimens remained in the artificially accelerated aging machine for 382 hours and were submitted to the same surface hardness analysis. The means of each test specimen were submitted to the Kolmogorov-Smirnov test (p > 0.05, ANOVA and Tukey test (p < 0.05. With regard to hardness (F = 86.74, p < 0.0001 the analysis showed significant differences among the resin composite brands. But aging did not influence the hardness of any of the resin composites (F = 0.39, p = 0.53. In this study, there was interaction between the resin composite brand and the aging factors (F = 4.51, p < 0.0002. It was concluded that notwithstanding the type of resin, AAA did not influence surface hardness. However, with regard to hardness there was a significant difference among the resin brands.

  13. Rotation of hard particles in a soft matrix

    Science.gov (United States)

    Yang, Weizhu; Liu, Qingchang; Yue, Zhufeng; Li, Xiaodong; Xu, Baoxing

    Soft-hard materials integration is ubiquitous in biological materials and structures in nature and has also attracted growing attention in the bio-inspired design of advanced functional materials, structures and devices. Due to the distinct difference in their mechanical properties, the rotation of hard phases in soft matrixes upon deformation has been acknowledged, yet is lack of theory in mechanics. In this work, we propose a theoretical mechanics framework that can describe the rotation of hard particles in a soft matrix. The rotation of multiple arbitrarily shaped, located and oriented particles with perfectly bonded interfaces in an elastic soft matrix subjected to a far-field tensile loading is established and analytical solutions are derived by using complex potentials and conformal mapping methods. Strong couplings and competitions of the rotation of hard particles among each other are discussed by investigating numbers, relative locations and orientations of particles in the matrix at different loading directions. Extensive finite element analyses are performed to validate theoretical solutions and good agreement of both rotation and stress field between them are achieved. Possible extensions of the present theory to non-rigid particles, viscoelastic matrix and imperfect bonding are also discussed. Finally, by taking advantage of the rotation of hard particles, we exemplify an application in a conceptual design of soft-hard material integrated phononic crystal and demonstrate that phononic band gaps can be successfully tuned with a high accuracy through the mechanical tension-induced rotation of hard particles. The present theory established herein is expected to be of immediate interests to the design of soft-hard materials integration based functional materials, structures and devices with tunable performance via mechanical rotation of hard phases.

  14. Hard X-ray imaging with a slat collimated telescope

    International Nuclear Information System (INIS)

    Lu Zhuguo; Kotov, Yu.D.; Suslov, A.Yu.

    1995-01-01

    Imaging experiments with a slat collimated hard X-ray telescope are described in this paper demonstrating the feasibility of the direct demodulation imaging method used in hard X-ray scanning modulation experiments. On 25 September 1993 an X-ray raster scan observation of Cyg X-1 was performed in a balloon flight with the hard X-ray telescope HAPI-4. An experiment to image radioactive X-ray sources was performed in the laboratory before. In both experiments the expected X-ray images were obtained, confirming the imaging capability of this method. (orig.)

  15. Dispersion representations for hard exclusive processes. Beyond the born approximation

    International Nuclear Information System (INIS)

    Diehl, M.; Ivanov, D.Yu.

    2007-07-01

    Several hard exclusive scattering processes admit a description in terms of generalized parton distributions and perturbative hard-scattering kernels. Both the physical amplitude and the hard-scattering kernels fulfill dispersion relations. We give a detailed investigation of their consistency at all orders in perturbation theory. The results shed light on the information about generalized parton distributions that can be extracted from the real and imaginary parts of exclusive amplitudes. They also provide a practical consistency check for models of these distributions in which Lorentz invariance is not exactly satisfied. (orig.)

  16. Electroerosion micro- and nanopowders for the production of hard alloys

    Science.gov (United States)

    Latypov, R. A.; Ageeva, E. V.; Kruglyakov, O. V.; Latypova, G. R.

    2016-06-01

    The shape and the surface morphology of the powder particles fabricated by the electroerosion dispersion of tungsten-containing wastes in illuminating oil are studied. The hard alloy fabricated from these powder particles is analyzed by electron-probe microanalysis. The powder synthesized by the electroerosion dispersion of the wastes of sintered hard alloys is found to consist of particles of a spherical or elliptical shape, an irregular shape (conglomerates), and a fragment shape. It is shown that W, Ti, and Co are the main elements in the hard alloy fabricated from the powder synthesized by electroerosion dispersion in illuminating oil.

  17. Excavation Technology for Hard Rock - Problems and Prospects

    International Nuclear Information System (INIS)

    Gillani, S.T.A.; Butt, N.

    2009-01-01

    Civil engineering projects have greatly benefited from the mechanical excavation of hard rock technology. Mining industry, on the other hand, is still searching for major breakthroughs to mechanize and then automate the winning of ore and drivage of access tunnels in its metalliferous sector. The aim of this study is to extend the scope of drag bits for road headers in hard rock cutting. Various factors that can impose limitations on the potential applications of drag bits in hard rock mining are investigated and discussed along with alternative technology options. (author)

  18. Performance ratio hardness characteristics polystyrene-metal composite materials

    International Nuclear Information System (INIS)

    Klepikov, V.F.; Prokhorenko, E.M.; Lytvynenko, V.V.; Zakharchenko, A.A.; Hazhmuradov, M.A.

    2015-01-01

    The methods of measuring the hardness of layered polystyrene-metallic composite materials. It is proposed to use powder-like tungsten and powder-like steel as radiation-protective layer. A measurement of the hardness of composites of different composition, and given its dependence on the particle size and their form. The possibility of increasing the hardness of the composites reinforced with metallic additives. Radiation-protective characteristics were calculated for the studied species of composite materials. Influence of the quantitative composition of the metal components is studied on the change of the absorbed dose of gamma radiation

  19. Application of hard coatings for blanking and piercing tools

    DEFF Research Database (Denmark)

    Podgornik, B.; Zajec, B.; Bay, Niels

    2011-01-01

    The aim of the present investigation was to examine the possibility of reducing lubrication and replacing expensive tungsten carbide material in blanking/piercing through introduction of hard tool coatings. Results show that hard PVD coatings can be successfully used in blanking/piercing...... critical value under dry friction conditions and leads to tool failure. Therefore, at present oxidation and temperature resistant hard coatings can give improved wear resistance of stamping tools, but elimination of lubricants in blanking and piercing processes is still not feasible....

  20. Micro-computer cards for hard industrial environment

    Energy Technology Data Exchange (ETDEWEB)

    Breton, J M

    1984-03-15

    Approximately 60% of present or future distributed systems have, or will have, operational units installed in hard environments. In these applications, which include canalization and industrial motor control, robotics and process control, systems must be easily applied in environments not made for electronic use. The development of card systems in this hard industrial environment, which is found in petrochemical industry and mines is described. National semiconductor CIM card system CMOS technology allows the real time micro computer application to be efficient and functional in hard industrial environments.