233 resultados para Viscoelastic Bi-Materials


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Large communities built around social media on the Internet offer an opportunity to augment analytical customer relationship management (CRM) strategies. The purpose of this paper is to provide direction to advance the conceptual design of business intelligence (BI) systems for implementing CRM strategies. After introducing social CRM and social BI as emerging fields of research, the authors match CRM strategies with a re-engineered conceptual data model of Facebook in order to illustrate the strategic value of these data. Subsequently, the authors design a multi-dimensional data model for social BI and demonstrate its applicability by designing management reports in a retail scenario. Building on the service blueprinting framework, the authors propose a structured research agenda for the emerging field of social BI.

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Our micro structural characterisation of Y-Ba-Cu-O quenched partial melts shows that the BaCuO2 (BC1) phase is crystalline at temperatures as high as 1100°C, and that the partial melt self-establishes a micro structural gradient from the surface towards the interior of the samples, which can be associated with a gradient in an equivalent partial pressure of O2 (pO2). The extension of the Y2BaCuO5-YBa2Cu3O7-x (Y211-Y123) tie-line intersects the primary crystallisation field of BC1 first. The actual peritectic reaction that takes place is Y2BaCuO5(s) + BaCuO2(s) + 2BaCu2O2(L) + 1/2O2 → 2YBa2Cu3O6(s). Two schematic representations which allow an analysis of the pO2 dependence are given. The gradient in micro structure self-established by the sample acts as a driving force for texturing. With this new perspective gained about the actual peritectic reaction and mechanisms of melt-texturing of Y123, it is possible to explain most of the aspects about partial melt-texturing. In addition, it seems possible to devise heat treatments that may allow for the production of well-oriented single domains with very large diameters. © 1999 Elsevier Science B.V.

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Layers (about 60-100 μm thick) of almost pure BaCuO2 (BC1), as determined using X-ray diffractometry (XRD) and scanning electron microscopy (SEM), coat the surfaces of YBa2Cu3O7-x (Y123) samples partial melt processed using a single-zone vertical furnace. The actual Cu/Ba ratio of the BC1 phase is 1.2-1.3 as determined using energy dispersive X-ray spectrometry (EDS). The nominally BC1 phase displays an exsolution of BC1.5 or BC2 in the form of thin plates (about 50-100 nm thick) along {100}-type cleavage planes or facets. The exsolved phase also fills cracks within the BC1 layer that require it to be in a molten state at some stage of processing. The samples were influenced by Pt contamination from the supporting wire, which may have stabilised the BC1.5 phase. Many of the Y123 grains have the same morphology as the exsolution domains, and run nearly parallel to the thin plates of the exsolved phases, strongly indicating that Y123 nucleation took place at the interface between the BC1 and the BC1.5 or BC2 exsolved phases. The network of nearly parallel exsolved 'channels' provides a matrix and a mechanism through which a high degree of local texture can be initiated in the material.

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Y123 samples with varying amounts of added Y211, PtO 2 and CeO 2 have been melt processed and quenched from temperatures between 960°C and 1100°C. The microstructures of the quenched samples have been characterized using a combination of x-ray diffractometry, optical microscopy, scanning electron microscopy, microprobe analysis, energy-dispersive x-ray spectroscopy and wavelength-dispersive x-ray spectroscopy. The Ba-Cu-O-rich melt undergoes complex changes as a function of temperature and time. A region of stability of BaCuO 2 (BC1) and BaCu 2O 2 (BC2) exists below 1040°C in samples of Y123 + 20 mol% Y211. Ba 2Cu 3O 5 is stabilized by rapid quenching but appears to separate into BC1 and BC2 at lower quenching rates. PtO 2 and CeO 2 additions affect the distribution and volume fractions of the two Ba-Cu-oxide phases.

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The microstructures of the quenched melts of samples of Y123 and Y123+15-20 mol% Y211 with PtO2 and CeO2 additives have been examined with optical microscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectrometry (EDS) and X-ray Diffractometry (XRD). Significantly higher temperatures are required for the formation of dendritic or lamellar eutectic patterns throughout the samples with PtO2 and CeO2 additives as compared to samples without additives. The BaCuO2 (BCl) phase appears first in solid form and, instead of rapidly melting, is slowly dissolving or decomposing in the oxygen depleted melt. PtO2 and CeO2 additives slow down or shift to higher temperatures the dissolution or decomposition process of BCl. A larger fraction of BCl in solid form explains why samples with additives have higher viscosities and hence lower diffusivities than samples without additives. There is also a reduction in the Y solubility to about half the value in samples without additives. The mechanism that limits the Ostwald ripening of the Y211 particles is correlated to the morphology of the quenched partial melt. It is diffusion controlled for a finely mixed morphology and interface-controlled when the melt quenches into dendritic or lamellar eutectic patterns. The change in the morphology of the Y211 particles from blocky to acicular is related to an equivalent undercooling of the Y-Ba-Cu-O partial melt, particularly through the crystallization of BCl.

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High temperature superconductor precursor billets (feed rods) have been developed for loading into silver tubes. The billets are loaded prior to rolling or drawing operations in PIT wire manufacture. Investigations have shown that wires and tapes prepared from feed rod loaded tubes show enhanced uniformity of electrical transport properties when compared with conventional powder packing, especially in wires drawn to long lengths. Analysis on production feed rods have shown carbon content to be as low as 110 ppm. © 1999 IEEE.

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The chemically reversible solid−solid phase transformation of a TCNQ-modified glassy carbon, indium tin oxide, or metal electrode into Co\[TCNQ]2(H2O)2 material in the presence of Co2+(aq) containing electrolytes has been induced and monitored electrochemically. Voltammetric data reveal that the TCNQ/Co\[TCNQ]2(H2O)2 interconversion process is independent of electrode material and identity of cobalt electrolyte anion. However, a marked dependence on electrolyte concentration, scan rate, and method of electrode modification (drop casting or mechanical attachment) is found. Cyclic voltammetric and double potential step chronoamperometric measurements confirm that formation of Co\[TCNQ]2(H2O)2 occurs through a rate-determining nucleation and growth process that initially involves incorporation of Co2+(aq) ions into the reduced TCNQ crystal lattice at the TCNQ|electrode|electrolyte interface. Similarly, the reverse (oxidation) process, which involves transformation of solid Co\[TCNQ]2(H2O)2 back to parent TCNQ crystals, also is controlled by nucleation−growth kinetics. The overall chemically reversible process that represents this transformation is described by the reaction:  2TCNQ0(s) + 2e- + Co2+(aq) + 2H2O \[Co(TCNQ)2(H2O)2](s). Ex situ SEM images illustrated that this reversible TCNQ/Co\[TCNQ]2(H2O)2 conversion process is accompanied by drastic size and morphology changes in the parent solid TCNQ. In addition, different sizes of needle-shaped nanorod/nanowire crystals of Co\[TCNQ]2(H2O)2 are formed depending on the method of surface immobilization.

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The formation of readily recoverable and reusable organic semiconducting Cu- and AgTCNQ (TCNQ=7,7,8,8-tetracyanoquinodimethane) microstructures decorated with Pt and Pd metallic nanoparticles is described for the effective reduction of CrVI ions in aqueous solution at room temperature using both formic acid and an environmentally friendly thiosulfate reductant. The M-TCNQ (M=metal) materials were formed by electrocrystallisation onto a glassy carbon surface followed by galvanic replacement in the presence of H2PtCl6 or PdCl2 to form the composite material. It was found that loading of the surface with nanoparticles could easily be controlled by changing the metal salt concentration. Significantly, the M-TCNQ substrates facilitated the formation of well-isolated metal nanoparticles on their surfaces under appropriate galvanic replacement conditions. The semiconductor–metal nanoparticle combination was also found to be critical to the catalyst performance, wherein the best-performing material was CuTCNQ modified by well-isolated Pt nanoparticles with both formic acid and thiosulfate ions as the reductant.

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A battery electrode for a lithium ion battery comprising an elec. conductive substrate having an electrode layer applied thereto, characterized in that the electrode layer includes an org. material having high alky., or an org. material which can be dissolved in org. solvents, or an org. material having an imide group(s) and aminoacetal group(s), or an org. material that chelates with or bonds with a metal substrate or that chelates with or bonds with an active material in the electrode layer. The org. material may be guanidine carbonate. [on SciFinder(R)]

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Bi-2212 thick film on silver tapes are seen as a simple and low cost alternative to high temperature superconducting wires produced by the Powder In Thbe (PIT) technique, particularly in react and wind applications. A rig for the continuous production of Bi-2212 tapes for use in react and wind component manufacture has been developed and commissioned. The rig consists of several sections, each fully automatic, for task specific duties in the production of HTS tape. The major sections are: tape coating, sintering and annealing. High temperature superconducting tapes with engineering critical current densities of 10 kA/cm2 (77 K, self field), and lengths of up to 100 m have been produced using the rig. Properties of the finished tape are discussed and results are presented for current density versus bend radius and applied strain. Depending on tape content and thickness, irreversible strain tirrm varies between 0.04 and 0.1 %. Cyclic bending tests when applied strain does not exceed Eirrm showed negligible reduction in J c along the length of the tape.

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Bi-2212 tapes were fabricated using a powder-in-tube method and their superconducting properties were measured as a function of heat treatment. The tapes were heated to temperature, T1 (884-915 °C), and kept at that temperature for 20 min to induce partial (incongruent) melting. The samples were cooled to T2 with a ramp rate of 120 °C h-1 and then slowly cooled to T3 with a cooling rate, R2, and from T3 to T4 with a cooling rate, R3. The tapes were kept at the temperature T4 for P1 hours and then cooled to room temperature. Both R1 and R2 were chosen between 2 and 8 °C h-1. It was found that the structure and Jc of the tapes depend on the sintering conditions, i.e. T1-4, R1-3 and P1. The highest Jc of 5800 Å cm-2 was obtained at 77 K in a self-field with heat treatment where T1 = 894 and 899 °C, R1 = R2 = 5 °C h-1 and P1 = 6 h were employed. When 0.7% of bend strain, which is equivalent to a bend radius of 5 mm, was applied to the tape, 80% of the initial Jc was sustained.

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A novel composite material based on deposition of nanosized zero-valent iron (nZVI) particles on acid-leached diatomite was synthesised for the removal of a chlorinated contaminant in water. The nZVI /diatomite composites were characterized by X-ray diffraction, scanning electron microscopy, elemental analysis, transmission electron microscopy and X-ray photoelectron spectroscopy. Compared with the pure nZVI particles, better dispersion of nZVI particles on the surface or inside the pores of diatom shells was observed. The herbicide simazine was selected as the model chlorinated contaminant and the removal efficiency by nZVI /diatomite composite was compared with that of the pristine nZVI and commercial iron powder. It was found that the diatomite supported nZVI composite material prepared by centrifugation exhibits relatively better efficient activity in decomposition of simazine than commercial Fe, lab synthesized nZVI and composite material prepared via rotary evaporation, and the optimum experimental conditions were obtained based on a series of batch experiments. This study on immobilizing nZVI particles onto diatomite opens a new avenue for the practical application of nZVI and the diatomite-supported nanosized zero-valent iron composite materials have potential applications in environmental remediation.

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The common goal of tissue engineering is to develop substitutes that can closely mimic the structure of extracellular matrix (ECM). However, similarly important is the intensive material properties which have often been overlooked, in particular, for soft tissues that are not to bear load assumingly. The mechanostructural properties determine not only the structural stability of biomaterials but also their physiological functionality by directing cellular activity and regulating cell fate decision. The aim here is to emphasize that cells could sense intensive material properties like elasticity and reside, proliferate, migrate and differentiate accordinglyno matter if the construct is from a natural source like cartilage, skin etc. or of synthetic one. Meanwhile, the very objective of this work is to provide a tunable scheme for manipulating the elasticity of collagen-based constructs to be used to demonstrate how to engineer cell behavior and regulate mechanotransduction. Articular cartilage was chosen as it represents one of the most complex hierarchical arrangements of collagen meshwork in both connective tissues and ECM-like biomaterials. Corona discharge treatment was used to produce constructs with varying density of crosslinked collagen and stiffness accordingly. The results demonstrated that elastic modulus increased up to 33% for samples treated up to one minute as crosslink density was found to increase with exposure time. According to the thermal analysis, longer exposure to corona increased crosslink density as the denaturation enthalpy increased. However the spectroscopy results suggested that despite the stabilization of the collagen structure the integrity of the triple helical structure remained intact. The in vitro superficial culture of heterologous chondrocytes also determined that the corona treatment can modulate migration with increased focal adhesion of cells due to enhanced stiffness, without cytotoxicity effects, and providing the basis for reinforcing three-dimensional collagen-based biomaterials in order to direct cell function and mediate mechanotransduction.

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Computer generated materials are ubiquitous and we encounter them on a daily basis, even though most people are unaware that this is the case. Blockbuster movies, television weather reports and telephone directories all include material that is produced by utilising computer technologies. Copyright protection for materials generated by a programmed computer was considered by the Federal Court and Full Court of the Federal Court in Telstra Corporation Limited v Phone Directories Company Pty Ltd. The court held that the White and Yellow pages telephone directories produced by Telstra and its subsidiary, Sensis, were not protected by copyright because they were computer-generated works which lacked the requisite human authorship. The Copyright Act 1968 (Cth) does not contain specific provisions on the subsistence of copyright in computer-generated materials. Although the issue of copyright protection for computer-generated materials has been examined in Australia on two separate occasions by independently-constituted Copyright Law Review Committees over a period of 10 years (1988 to 1998), the Committees’ recommendations for legislative clarification by the enactment of specific amendments to the Copyright Act have not yet been implemented and the legal position remains unclear. In the light of the decision of the Full Federal Court in Telstra v Phone Directories it is timely to consider whether specific provisions should be enacted to clarify the position of computer-generated works under copyright law and, in particular, whether the requirement of human authorship for original works protected under Part III of the Copyright Act should now be reconceptualised to align with the realities of how copyright materials are created in the digital era.