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Technical Applications (technical + application)
Selected AbstractsDesign of the Magnetic Properties of Fe-Rich, Glass-Coated Microwires for Technical Applications,ADVANCED FUNCTIONAL MATERIALS, Issue 5 2006A. Zhukov Abstract The magnetic anisotropy of Fe-rich, thin, amorphous wires is tailored by stress annealing (SA). In particular, the effect of conventional annealing (CA) and SA on the magnetic properties of Fe74B13Si11C2 glass-coated microwires is studied. CA treatment does not significantly change the character of the hysteresis loop. Under certain SA conditions (annealing temperature, Tann,>,300,°C; applied stress, ,,>,400,MPa), a transverse magnetic anisotropy is induced: a rectangular hysteresis loop transforms into an inclined one at magnetic-anisotropy fields above 1000,A,m,1. Under tensile stress, the rectangular hysteresis loop of microwires annealed using SA is recovered. Samples subjected to SA show noticeable magnetoimpedance and stress-impedance effects, despite their large magnetostriction. The samples obtained exhibit a high stress sensitivity of their giant magnetoimpedance (GMI) effect and hysteretic properties, allowing the use of the obtained samples in magnetoelastic sensors, and for designing stress-sensitive, tunable composite materials. By varying the time and temperature of such SA, we are able to tailor both the magnetic properties and the GMI of Fe-rich microwires. [source] Cyclopropyl Building Blocks for Organic Synthesis, 131.ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 15 2006Palladium-Catalyzed Bicyclization with Carbonyl Insertion of Alkenyl-Tethered Propargyl Carbonates Towards a Scalable Synthesis of Various 2-(Bicyclo[3.1.0]hex-1-yl)acrylates Abstract The Pd-catalyzed 5- exo-trig- 3 -exo-trig cascade cyclization of 1,6-enynes with a propargyl carbonate terminus offers the shortest synthetic route to variously substituted 2-(bicyclo[3.1.0]hex-1-yl)acrylates, a novel class of prospective monomers for low-shrinkage polymers. To apply this reaction to large-scale preparations of the said bicyclic acrylates, a flexible Pd catalyst system with tunable reactivity has been developed. The dependence of the product and diastereomer distribution on both the reaction conditions, including the type of palladium catalyst used, and on the nature of the substrate has been investigated. A variety of methyl 2-(bicyclo[3.1.0]hex-1-yl)acrylates and parent carboxylic acids as well as some of their derivatives of potential interest towards a technical application were prepared on a multigram scale. A general large-scale synthesis of the cyclization precursors bearing one or two carbonyl groups in the tether is also disclosed. [source] Catalytic Hydroxylation in Biphasic Systems using CYP102A1 MutantsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7-8 2005Steffen Abstract Cytochrome P450 monooxygenases are biocatalysts that hydroxylate or epoxidise a wide range of hydrophobic organic substrates. Their technical application is, however, limited to a small number of whole-cell processes. The use of the isolated P450 enzymes is believed to be impractical due to their low stability, stoichiometric need of the expensive cofactor NAD(P)H and low solubility of most substrates in aqueous media. We investigated the behaviour of an isolated bacterial monooxygenase (mutants of CYP102A1) in a biphasic reaction system supported by cofactor recycling with the NADP+ -dependent formate dehydrogenase from Pseudomonas sp 101. Using this experimental set-up cyclohexane, octane and myristic acid were hydroxylated. To reduce the process costs a novel NADH-dependent mutant of CYP102A1 was designed. For recycling of NADH an NAD+ -dependent FDH was used. The stability of the monooxygenase mutants under the reaction conditions in the biphasic system was quite high as revealed by total turnover numbers of up to 12,850 in the NADPH-dependent cyclohexane hydroxylation and up to 30,000 in the NADH-dependent myristic acid oxidation. [source] Production of a Polyester Degrading Extracellular Hydrolase from Thermomonospora fuscaBIOTECHNOLOGY PROGRESS, Issue 5 2002Mona K. Gouda The production of a polyester-degrading hydrolase from the thermophilic actinomycete Thermomonospora fusca was investigated with regard to its potential technical application. Only in the presence of a polyester (random aliphatic-aromatic copolyester from 1,4-butanediol, terephthalic acid, and adipic acid with around 40,50 mol % terephthalic acid in the acid component), the excretion of the extracellular enzyme could be achieved with an optimized synthetic medium using pectin and NH4Cl as nitrogen source. Compared to complex media, a significantly higher specific activity at comparable volumetric yields could be obtained, thus reducing the expenditure for purification. The activity profile in the medium is controlled by a complex process involving (1) induction of enzyme excretion, (2) enzyme adsorption on the hydrophobic polyester surface, (3) inhibition of enzyme generation by monomers produced by polyester cleavage, and (4) enzyme denaturation. Diafiltration with cellulose acetate membranes as the sole downstream processing step led to a product of high purity and with sufficient yield (60% of total activity). Scaling-up from shaking flasks to a fermentor scale of 100 L revealed no specific problems. However, the excretion of the hydrolase by the actinomycete turned out to be inhibited by the degradation products (monomers) of the aliphatic-aromatic copolyester used as inductor for the enzyme production. The crude enzyme exhibited generally similar properties (temperature and pH optimum) as the highly purified hydrolase described previously; however, the storage capability and thermal stability is improved when the crude enzyme solution is diafiltrated. [source] Self-Assembly and Self-Orientation of Truncated Octahedral Magnetite Nanocrystals,ADVANCED MATERIALS, Issue 18 2006K. Zheng Monodisperse magnetite nanoparticles (12,nm) in the shape of Wigner,Seitz crystals self-assemble into a body-centered cubic superlattice (see figure) in which the nanoparticles possess the same crystallographic orientations. Shape plays a critical role in controlling the orientation of the nanoparticles in self-assembly. Both self-assembly and self-orientation of nanoparticles are important for technical applications such as high-density magnetic storage. [source] Poly(vinyl chloride) on the way from the 19th century to the 21st centuryJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 3 2004D. Braun Abstract Despite all the technical and economic problems and the public discussions on the environmental dangers and hazards of chlorine chemistry, poly(vinyl chloride) (PVC) is the second most produced plastic (with a worldwide capacity of about 31 million tons), placing after polyolefins and before styrene polymers. Presently, PVC production worldwide is growing at a rate of more than 4% per year. The application of PVC was first described in a patent in 1913, but only after 1930 did a sustained interest in PVC arise in several industrial laboratories. The most remarkable milestones in PVC history and their importance to the development of macromolecular chemistry are briefly described, and some present PVC research and industrial applications, with respect to polymerization, stabilization, bulk property modification, and chemical and material recycling of PVC waste, are discussed. Some actual selected topics include the emulsion polymerization of vinyl chloride with polymeric surfactants and controlled free-radical polymerization with nitroxyls, whereas ionic and metal organic initiators have not found any technical applications. Chemical reactions offer many possibilities for the modification of PVC, but they have been not used on a technical scale yet. Much work has been done on stabilization with nontoxic or metal-free systems. The bulk properties of PVC can be influenced by impact modification through the addition of graft copolymers or by blending with other polymers. Also presented are some problems and recent developments in PVC recycling. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 578,586, 2004 [source] Temperature measurements in combustion,not only with CARS: a look back at one aspect of the European CARS WorkshopJOURNAL OF RAMAN SPECTROSCOPY, Issue 12 2003W. Stricker Abstract Temperature is perhaps the most important quantity in combustion research and technology. The potential and state of the art of various laser-based diagnostics used for the determination of temperature in laboratory flames and practical combustion devices are discussed and illustrated with a few representative examples from our laboratory. The emphasis is on coherent anti-Stokes Raman scattering (CARS), the main topic of the European CARS Workshop in the past. As a result, CARS is today the most matured and proven technique for technical applications. In addition to CARS, however, linear laser spectroscopic methods also deliver valuable and supplementary information on temperature in combustion. Copyright © 2003 John Wiley & Sons, Ltd. [source] Simultaneous Measurement of Particle Size and Particle Velocity by the Spatial Filtering Technique,PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 6 2002Dieter Petrak Abstract The objective of this study was to compare the measuring results of a fiber-optical probe based on a modified spatial filtering technique with given size distributions of different test powders and also with particle velocity values of laser Doppler measurements. Fiber-optical spatial filtering velocimetry was modified by fiber-optical spot scanning in order to determine simultaneously the size and the velocity of particles. The fiber-optical probe system can be used as an in-line measuring device for sizing of particles in different technical applications. Spherical test particles were narrow-sized glass beads in the range 30,100,,m and irregularly shaped test particles were limestone particles in the range 10,600,,m. Particles were dispersed by a brush disperser and the measurements were carried out at a fixed position in a free particle-laden air stream. Owing to the measurement of chord lengths and to the influence of diffraction and divergent angle, the probe results show differences from the given test particle sizes. Owing to the particle-probe collisions, the mean velocity determined by the probe is smaller than the laser Doppler mean velocity. [source] Temperature and frequency investigations of the electrical parameters in the TGS ferroelectric transitionPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 5 2010Ciceron Berbecaru Abstract Pure and D: alanina doped triglycin sulphate (TGS) crystals were grown from aqueous solutions. Fresh cleaved, polished and silver paste painted samples were temperature and frequency investigated. Pure crystals show nonreproducible values of the permittivity and dielectric loss crossing up and down the Curie point. More stable and much lower values of the permittivity and dielectric loss could be noticed for D: alanina doped crystals. Permittivity and loss values show different frequencies behavior related to polar or nonpolar state of crystals. Frequency dependence of permittivity and loss behavior could be related to the general picture of relaxation of different polarization mechanisms and their contributions to permittivity and loss values for dielectric materials. Much smaller and stable values of permittivity and loss, vs. temperature and frequency, were found for doped crystals. Experimental results point out for a more stable structure with dipoles mobility decreased of doped vs. pure TGS crystals. Thus, higher figure of merit of doped TGS crystals point to a major advantage for technical applications (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Chromogenic polymer gels for reversible transparency and color control with temperature at a constant volumePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 7 2002A. Seeboth Abstract The preparation and characterization of novel chromogenic materials has developed extremely rapid in the last years. Among them, thermotropic and thermochromic polymer gel networks have met with growing interest, because of their advanced properties. These novel polymer gels exhibit pronounced changes in transparency and/or color intensity in a practically relevant temperature range. For many future technical applications it is an essential condition, that the volume of the used gel materials is independent of temperature. A current overview of this field is given. Copyright © 2002 John Wiley & Sons, Ltd. [source] Damped vibrations of the beam systems in rotational transportationPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2009kiewskiArticle first published online: 5 MAR 2010 The major aim of this thesis is dynamical analysis of systems in rotational transportation with taking into consideration in the mathematical models the damping forces. The dissipation of energy in form of damping is inseparable connected with motion of analyzed systems. Up to now modelling of rod and beam systems in transportation was very often based on simplification and reduction of damping effect and on the other side the considerations very rarely apply to systems where the transportation effect was took into consideration. In this thesis the dynamical flexibility of the damped beam systems in transportation was presented. Analyzing systems were assumed as simple homogenous beam systems with symmetrical cross-section constant on whole length of the system. Most popular technical applications of such systems are put into use in propellers and sails of wind power plant, main, auxiliary rotors of helicopters, turbines, etc. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Amplitude- and temperature effects of filler-reinforced rubber: Experiments and ModellingPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2008Martin Rendek Rubber,like materials exhibit special mechanical properties in a wide range of technical applications. To achieve a desired behaviour of the end product, the materials are reinforced with active fillers like carbon black. In the focus of this paper are selected cyclic,monofrequent experiments with constant strain amplitudes. Special attention will be focused to the excitation with small dynamic amplitudes. The amplitude dependence of the storage and loss moduli is known as the Payne,effect. We study the amplitude, and temperature dependence of storage and loss modulus as well as dissipation effects. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Leading Business Improvement: a New Role for Statisticians and Quality ProfessionalsQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 3 2005Ronald D. Snee Abstract Following the successes of Motorola, Allied-Signal, General Electric and others, many companies are implementing the Six Sigma approach to business improvement. Millions of dollars are being saved in the process. Active leadership by management and others involved is integral to the method and critical to its success. This development provides a unique opportunity for statisticians and quality professionals to be leaders in their organizations. The leadership roles are discussed and it is shown how statisticians and quality professionals can assume leadership roles throughout the deployment process. As a result statisticians and quality professionals can expand their roles as internal trainers and consultants to include being leaders of business improvement. In the process their focus moves from facilitation of technical applications to the implementation of Six Sigma, skill deployment and delivery of bottom line business results. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||||||||