Regeneration efficiency of composites containing two‐sized capillaries

The aim of this work is to develop a composite material containing a regeneration system and to demonstrate its self‐healing properties. For this purpose, we will study the self‐healing behavior of composites that are fabricated with a regeneration system consisting of two‐sized capillaries filled with epoxy resin and hardener. Composites with restorative systems containing identical microtube diameters can be found in the literature, but until now no comparative studies with multiple diameter structures have been published. We will prove that a regeneration system containing two types of capillaries with diameters of 100 and 50 μm is more efficient (68% recovery of bending strength and Young's modulus after third regeneration) than a regeneration system containing capillaries with the same diameter (44% recovery of bending strength and 44% recovery of Young's modulus after third regeneration). POLYM. COMPOS. 37:1223–1230, 2016. © 2014 Society of Plastics Engineers     

Thermoluminescence features of alumina-mixed borophosphate glasses with Tb3+ ions for dosimetric applications

Amorphous barium borophosphate materials doped with small quantity of terbium ions and with the addition of some amounts of alumina were prepared. Thermoluminescence (TL) characteristics of these glasses were investigated after irradiating them with different doses of γ-rays (in the range 0.5-8.0 kGy). The TL emission exhibited a dosimetric peak at about 210°C. The TL output under this glow peak is observed to increase with the γ-ray dose. For any fixed γ-ray dose, the TL output is increased with increase in Al₂O₃ content up to 3.0 mol%, and beyond this concentration, quenching of TL is visualized. The dose response of TL output of these glasses exhibited linear behavior in the dose range 0.5-4.0 kGy. The mechanisms responsible for TL emission and the variation of TL output with the concentration of Al₂O₃ are quantitatively discussed in terms of structural defects induced during γ-ray irradiation. Finally, it is concluded that these glasses are potential materials for dosimetry applications in the dose range 0.5-4.0 kGy.     

Comparative study of the hydrolytic degradation of glycolide/L‐lactide/ε‐caprolactone terpolymers initiated by zirconium(IV) acetylacetonate or stannous octoate

A series of copolymers have been synthesized by the ring‐opening polymerization of glycolide, L ‐lactide, and ?‐caprolactone with zirconium(IV) acetylacetonate [Zr(Acac)₄] or stannous octoate [Sn(Oct)₂] as the catalyst. The resulting terpolymers have been characterized by analytical techniques such as proton nuclear magnetic resonance, size exclusion chromatography, and differential scanning calorimetry. Data have confirmed that Sn(Oct)₂ leads to less transesterification of polymer chains than Zr(Acac)₄ under similar conditions. The various copolymers have been compression‐molded and allowed to degrade in a pH 7.4 phosphate buffer at 37°C. The results show that the degradation rate depends not only on the copolymer composition but also on the chain microstructure, the Sn(Oct)₂‐initiated copolymers degrading less rapidly than Zr(Acac)₄‐initiated ones with more random chain structures. The caproyl component appears the most resistant to degradation as its content increases in almost all cases. Moreover, caproyl units exhibit a protecting effect on neighboring lactyl or glycolyl units. The glycolyl content exhibits different features: it decreases because of faster degradation of glycolyl units, which are more hydrophilic than caproyl and lactyl ones, remains stable in the case of abundant C? G? C sequences, which are very resistant to degradation, or even increases because of the formation of polyglycolide crystallites. Terpolymers can crystallize during degradation if the block length of one of the components is sufficiently long, even though they are amorphous initially. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Fire Experiment Inside a Very Large and Open-Plan Compartment: x-ONE

Fire Technology - The traditional design fires commonly considered in structural fire engineering, like the standard fire and Eurocode parametric fires, were developed several...     

Albumin–Hyaluronan Interactions: Influence of Ionic Composition Probed by Molecular Dynamics

The lubrication mechanism in synovial fluid and joints is not yet fully understood. Nevertheless, intermolecular interactions between various neutral and ionic species including large macromolecular systems and simple inorganic ions are the key to understanding the excellent lubrication performance. An important tool for characterizing the intermolecular forces and their structural consequences is molecular dynamics. Albumin is one of the major components in synovial fluid. Its electrostatic properties, including the ability to form molecular complexes, are closely related to pH, solvation, and the presence of ions. In the context of synovial fluid, it is relevant to describe the possible interactions between albumin and hyaluronate, taking into account solution composition effects. In this study, the influence of Na⁺, Mg²⁺, and Ca²⁺ ions on human serum albumin–hyaluronan interactions were examined using molecular dynamics tools. It was established that the presence of divalent cations, and especially Ca²⁺, contributes mostly to the increase of the affinity between hyaluronan and albumin, which is associated with charge compensation in negatively charged hyaluronan and albumin. Furthermore, the most probable binding sites were structurally and energetically characterized. The indicated moieties exhibit a locally positive charge which enables hyaluronate binding (direct and water mediated).     

Numerical analysis of shock induced separation delay by air humidity

In this paper numerical calculations of the dry and humid air flows in the nozzle are presented. The dry air flow (adiabatic flow) and the humid air flow (flow with homogeneous condensation, diabatic flow) are modeled with the use of Reynolds Averaged Navier-Stokes (RANS) equations. The comparison of these two types of flow is carried out. The influence of the air humidity on the shock wave location and its interaction with the boundary layer is examined. Obtained numerical results present a first numerical approach of the condensation and evaporation process in transonic flow of humid air. The phenomena considered here are very complex and complicated and need further in-depth numerical analysis.     

Optimization technology for nonlinear microwave circuits integrating electromagnetic simulations

We review relevant concepts, formulations, and algorithms for microwave circuit optimization. Emphasis is given to recent advances in the state of the art: Automated electromagnetic (EM) design, Space Mapping, Huber optimization, an integrated CAD environment, and parallel computation. We address integration of previously disjoint simulation technologies for automated EM optimization of linear and nonlinear microwave circuits. We incorporate EM analyses of passive microstrip structures and SPICE models of active devices into harmonic balance optimization of nonlinear circuits, even for yield-driven design. Designs of a Class B frequency doubler, a broadband small-signal amplifier, and an attenuator illustrate the integrated approach. © 1997 John Wiley & Sons, Inc. Int J Microwave Millimeter-Wave CAE 7: 6–28, 1997.     

Java enabling collaborative education,health care,and computing

Web technologies – in particular linked Java servers and clients – allow new dynamic collaborative environments linking people and computers. We describe the architecture of a system, TANGOsim, that combines a Java collaborative environment with an executive providing general message filters, and an event-driven simulator. The initial application is to command and control, but we describe how this approach can also be used in other areas, such as health care, scientific visualization and (distance) education. © 1997 John Wiley & Sons, Ltd.     

Large-scale phenotypic analysis—the pilot project on yeast chromosome III

In 1993, a pilot project for the functional analysis of newly discovered open reading frames, presumably coding for proteins, from yeast chromosome III was launched by the European Community. In the frame of this programme, we have developed a large-scale screening for the identification of gene/protein functions via systematic phenotypic analysis. To this end, some 80 haploid mutant yeast strains were constructed, each carrying a targeted deletion of a single gene obtained by HIS3 or TRP1 transplacement in the W303 background and a panel of some 100 growth conditions was established, ranging from growth substrates, stress to, predominantly, specific inhibitors and drugs acting on various cellular processes. Furthermore, co-segregation of the targeted deletion and the observed phenotype(s) in meiotic products has been verified. The experimental procedure, using microtiter plates for phenotypic analysis of yeast mutants, can be applied on a large scale, either on solid or in liquid media. Since the minimal working unit of one 96-well microtiter plate allows the simultaneous analysis of at least 60 mutant strains, hundreds of strains can be handled in parallel. The high number of monotropic and pleiotropic phenotypes (62%) obtained, together with the acquired practical experience, have shown this approach to be simple, inexpensive and reproducible. It provides a useful tool for the yeast community for the systematic search of biochemical and physiological functions of unknown genes accounting for about a half of the 6000 genes of the complete yeast genome. © 1997 John Wiley & Sons, Ltd.