bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi-Scale Modeling of Texture Evolution in Beryllium and Zirconium during Equal Channel Angular Extrusion
Authors: Beyerlein Irene J. , Capolungo Laurent , Yapici G.G. , Tomé Carlos N. , Karaman Ibrahim
Published: December 2009

This work studies the deformation mechanisms active in two pure hexagonal close packed metals, beryllium (Be) and zirconium (Zr), during equal channel angular extrusion processing. An experimental-theoretical approach is employed to assess their relative contributions through measurement and calculation of texture evolution. A new multi-scale constitutive model, incorporating thermally activated dislocation density based hardening, is shown to effectively predict texture evolution as a function of processing route, number of passes (up to four), initial texture, pressing rate, and processing temperature. Texture predictions are shown to be in very good agreement with experimental measurements. Also, it is found that the two most active deformation modes in Be are basal slip and prismatic slip, where the predominant one is interestingly found to depend on die angle. Deformation in Zr during the first pass is predicted to be accommodated not only by its easiest mode, prismatic slip, but by basal slip and tensile twinning.
Processing Age-Hardenable Alloys by Equal-Channel Angular Pressing at Room Temperature: Strategies and Advantages
Authors: Chinh Nguyen Q. , Gubicza Jenő , Czeppe Tomasz , Lendvai János , Langdon Terence G.
Published: December 2009

The effect of the combination of natural aging and severe plastic deformation (SPD) produced by Equal-Channel Angular Pressing (ECAP) on the microstructure, the strength, as well as the ductility of age-hardenable AlZnMg alloys was investigated. A strategy is proposed for the processing of these “difficult-to-work” alloys at room temperature. Several advantages such as strengthening, precipitation-accelerating and ductility-improving effects of ECAP at room temperature are also shown and discussed in this work.
Crack Blunting through Lattice Dislocation Slip in Nanocrystalline and Ultrafine-Grained Materials
Authors: Ovidko Ilya A. , Sheinerman A.G.
Published: December 2009

The grain size effect on blunting of cracks in nanocrystalline and ultrafine-grained materials (UFG) is theoretically described. Within our description, lattice dislocations emitted from cracks are stopped at grain boundaries. The stress fields of these dislocations suppress further dislocation emission from cracks in nanocrystalline and UFG materials, and the suppression depends on grain size. The dependences of the number of dislocations emitted by a crack on grain size (ranging from 10 to 300 nm) in Cu and 3C-SiC (the cubic phase of silicon carbide) are calculated which characterize the grain size effect on crack blunting that crucially influences ductility of these materials.
Processing Dense Hetero-Nanostructured Metallic Materials for Improved Strength/Ductility Balance through High Strain Deformation and Electrical Current Assisted Sintering (ECAS)
Authors: Grosdidier Thierry , Llorca-Isern Núria
Published: December 2009

This paper has examined some recent findings concerning the processing of fully dense hetero-nanostructured materials (i.e. consisting of nano, ultrafine and micrometric grains) which can be produced by using the interplay between heavy deformation and recrystallization. By plastic deformation of bulk materials, an improved strength/ductility balance can be obtained directly by imparting high strain deformation (by ECAE) until the occurrence of recrystallization. Using a powder metallurgy route, the strong potential of electric field assisted sintering (ECAS) for producing multi-scale microstructures when a milled powder is used is also demonstrated. In this case, in addition to modify the classic processing parameters (time/temperature of ECAS), altering the nature of the milled powder - by Y2O3 addition during the milling stage - is also a good way to delay the onset of recrystallization and, thereby, increase the fraction of ultrafine grains.
Structure Refinement and Electropulse Current Effect on Mechanical Properties of Shape Memory TiNi Alloy
Authors: Stolyarov Vladimir V.
Published: December 2009

The paper presents data on structure refinement and electropulse current effects on deformability, strength and ductility of shape memory TiNi alloy, processed different severe plastic deformation techniques including equal channel angular pressing and electroplastic rolling. It was found that deformability and elongation to failure decreases with grain refinement but they can be enhanced by electropulse current.
Effect of Grain Size on Defects Density and Internal Stresses in Sub-Microcrystals
Authors: Koneva Nina , Kozlov Eduard , Popova N.A. , Fedorischeva M.V.
Published: December 2009

The paper is devoted to research of an influence of average grains size on scalar dislocation density, fraction of geometrically necessary dislocations, internal stresses and bending- torsion of crystal lattice. Polycrystals of submicrocrystalline copper produced by torsion under hydrostatic pressure were investigated by TEM method.
In Situ Transmission Electron Microscopy Investigation of the Deformation Behavior of Cu with Nanoscale Twins
Authors: Wang Y. B. , Sui M.L.
Published: December 2009

This paper reviews our recent studies on the effect of twin boundary (TB) on the deformation behavior in Cu with nanoscale growth twins. In situ straining transmission electron microscopy investigations on TB migration, TBs and twin ends acting as dislocation emission sources, and the interactions between dislocations and TBs are highlighted. Results provide some useful understanding of why Cu with nanoscale twins leads to a combination of ultrahigh strength and high ductility.
Room-Temperature Mechanical Characterization of Bulk Glassy and Partially Crystallized Zr63Al9.7Ni9.7Cu14.6Nb3 Alloys
Authors: Li F.W. , Qiang Jian Bing , Quan S.G. , Wang Qing , Dong Chuang , Wang Ying Min
Published: December 2009

The microstructures and mechanical behavior of the as-cast and isothermally annealed Zr63Al9.7Ni9.7Cu14.6Nb3 bulk metallic glasses (BMGs) were studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM), and room temperature uniaxial compression. The as-cast BMG alloy shows a wide undercooled liquid span of 73 K at a constant heating rate of 40 K/min. Composite microstructures containing nanometer scaled icosahedral quasicrystals (i-phase) were produced upon annealing at 705 K. Under uniaxial room-temperature compression at a strain rate of 510-4 s-1, the as-cast BMG alloy exhibits a elastic deformation εy ~ 1.95%, a yield stress σy ~ 1650 MPa, and a Young’s modulus E ~ 84.5 GPa. The alloy shows a plastic strain εp ~ 8.0 % in a serrated plastic deformation process. Annealing induced embrittlement was observed in the relaxed BMG alloys. Comparing with the as-cast alloy, the relaxed and the composite alloys show negligible changes in elastic strain and Young’s modulus. The partially crystallized alloys are macroscopically brittle. Well developed vein patterns were observed in the fracture surfaces of all these alloys. The present work revealed that the dispersion of nanometer scaled i-phase particles is not effective as a barrier against shear localization in these partially quasicrystallized alloys.
Influence of HVOF Thermal Spray Process on the Microstructures and Properties of Fe-Based Amorphous / Nano Metallic Coatings
Authors: Liu X.Q. , Zheng Y.G. , Chang X.C. , Hou W.L. , Wang Jian Qiu
Published: December 2009

A new Fe-based amorphous / nano metallic coating with a good combination of high microhardness and excellent erosion corrosion resistance was produced by high velocity oxygen fuel (HVOF). The coating microstructure, amorphous phase content and properties under different HVOF processes were evaluated. It was found that they are very sensitive to the powder feed rate, stand-off distance and oxygen flow. This high performance amorphous / nano metallic coating could be applied as a good alternative material in erosion and corrosion environments.
Strain Enhanced High Strength Cu–Ag–Zr Conductors
Authors: Lyubimova Julia , Freudenberger Jens , Gaganov Alexandere , Klauss Hansjörg , Schultz Ludwig
Published: December 2009

Recovery, recrystallisation and grain growth processes as well as the formation of a solid solution and the phase separation of a homogeneous material into a heterogeneous one are observed for Cu-Ag-Zr alloys heat-treated at different temperatures by means of mechanical, electrical and microstructural analyses. Heat treatments are shown to be an effective tool to enhance the strain to failure. If applied between several deformation steps the heat treatment causes an increase of both strain and strength limits.
Structural, Magnetic and Transport Properties of Ni-Fe-Al Alloys
Authors: Kaul S.N. , Abhyankar A.C. , Sridhar Rao D.V. , Muraleedharan K. , Nigam A.K. , Fernández Barquín L.
Published: December 2009

Melt spun ribbons (MSR) of the Ni55Fe20Al25 alloy exhibit a first-order martensitic transition (MT) in the vicinity of a second-order ferromagnetic-to-paramagnetic phase transition. Contrasted with a sharp, complete and thermoelastic MT in MSR, a partial, sluggish and non-thermoelastic MT occurs in annealed Ni55Fe20Al25 alloy that possesses a much higher degree of atomic order. However, the annealed samples have stronger local magnetocrystalline anisotropy and higher Curie temperature (TC) than MSR. Negative magnetoresistance, || / , is two times larger in MSR than in the annealed case. || /  vs. H isotherms in MSR change curvature from concave-upwards to concave-downwards as the temperature is raised through TC whereas concave-downward curvature persists over the entire temperature range in the annealed counterpart.
Recent Developments in Ni-Mn-Ga Foam Research
Authors: Müllner Peter , Zhang Xue Xi , Boonyongmaneerat Yuttanant , Witherspoon Cassie , Chmielus Markus , Dunand David C.
Published: December 2009

Grain boundaries hinder twin boundary motion in magnetic shape-memory alloys and suppress magnetic-field-induced deformation in randomly textured polycrystalline material. The quest for high-quality single crystals and the associated costs are a major barrier for the commercialization of magnetic shape-memory alloys. Adding porosity to polycrystalline magnetic-shape memory alloys presents solutions for (i) the elimination of grain boundaries via the separation of neighboring grains by pores, and (ii) the reduction of production cost via replacing the directional solidification crystal growth process by conventional casting. Ni-Mn-Ga foams were produced with varying pore architecture and pore fractions. Thermo-magnetic training procedures were applied to improve magnetic-field-induced strain. The cyclic strain was measured in-situ while the sample was heated and cooled through the martensitic transformation. The magnetic field-induced strain amounts to several percent in the martensite phase, decreases continuously during the transformation upon heating, and vanishes in the austenite phase. Upon cooling, cyclic strain appears below the martensite start temperature and reaches a value larger than the initial strain in the martensite phase, thereby confirming a training effect. For Ni-Mn-Ga single crystals, external constraints imposed by gripping the crystal limit lifetime and/or magnetic-field-induced deformation. These constraints are relaxed for foams.
Evaluation of Magnetostriction of the Single-Variant Ni-Mn-Ga Martensite
Authors: L'vov Victor A. , Glavatskyy Ilya , Glavatska Nadiya
Published: December 2009

The temperature dependence of ordinary magnetostriction of the axially compressed Ni–Mn–Ga alloy with the low values of shear elastic modulus C'(T) ~ 1 – 10 GPa has been evaluated theoretically in the framework of Landau theory. The computations showed that the compression with 50 MPa stress reduces the ordinary magnetostriction by factor 3 at room temperature. Nevertheless, the magnetostriction of compressed alloy exceeds the value of 10–4 in the whole temperature range of martensitic phase stability, strongly depends on the temperature in the vicinity of martensitic transformation (MT), and is practically constant well below MT temperature. Therefore, the purposeful search for the alloy with the low value of shear elastic modulus and high MT temperature (well above 300 K) may result in the discovery of good magnetostrictive material. This material will posses the temperature-independent magnetostriction value about of 10–4 –10–3 and rather low electric conductivity enabling the technical applications of this material in dynamic regimes.
Recent Progress in FSMA Microactuator Developments
Authors: Kohl Manfred , Reddy Y. Srinivasa , Khelfaoui Fadila , Krevet Berthold , Backen A. , Fähler S. , Eichhorn Tobias , Jakob Gerhard , Mecklenburg A.
Published: December 2009

The giant magneto-strain effect is particularly attractive for actuator applications in micro- and nanometer dimensions as it enables contact-less control of large deformations, which can hardly be achieved by other actuation principles in small space. Two different approaches are being pursued to develop ferromagnetic shape memory (FSMA) microactuators based on the magnetically induced reorientation of martensite variants: (1) the fabrication of free-standing epitaxial Ni-Mn-Ga thin film actuators in a bottom-up manner by magnetron sputtering, substrate release and integration technologies and (2) the top-down approach of thickness reduction of bulk Ni-Mn-Ga single crystals to foil specimens of decreasing thicknesses (200 – 40 μm) and subsequent integration. This review describes the fabrication technologies, procedures for thermo-mechanical training adapted to the quasi-two-dimensional geometries of film and foil specimens as well as the performance characteristics of state-of-the art actuators after processing and training.
Structural and Magnetic Properties of Epitaxial Ni2MnGa Thin Films
Authors: Eichhorn Tobias , Jakob Gerhard
Published: December 2009

We report on the preparation and investigation of epitaxial thin films of the magnetic shape memory alloy Ni2MnGa. For samples close to the stoichiometric composition we find that the phase transformation temperature is affected by the crystallographic orientation. Changes in the crystal structure due to the transformation are observed using temperature-dependent X-ray diffraction. Films with higher manganese content are in the martensitic state at room temperature. Those samples on Al2O3(11-20) reveal the 7-layered orthorhombic structure that allows strains up to 10 %. To avoid blocking of magnetostrictive effects by the substrate, free-standing films are prepared using water-soluble NaCl(100) single crystals as substrate.
Thermodynamic Modelling of Ferromagnetic Shape Memory Actuators
Authors: Krevet Berthold , Kohl Manfred
Published: December 2009

We present a thermodynamic Gibbs free energy model for the finite element simulation of the coupled thermo-magneto-mechanical behavior of ferromagnetic shape memory alloys (FSMAs). Starting from a free energy model for the conventional shape memory effect, additional terms are included to take into account the magnetic anisotropy and the geometry-dependent magnetostatic energy. Different functions are considered for the strain dependence of the anisotropy energy in order to describe the experimentally found strong dependence of the anisotropy energy on the ratio of short and long crystallographic axis c/a. The resulting energy landscape is used to calculate the transition probabilities between three martensite variants and the austenite state under applied stress and external magnetic field. The magnetic shape memory effect is simulated for different loading conditions and sample geometries. We demonstrate the influence of the c/a dependence of the anisotropy energy as well as the influence of twinning strain and elastic modulus on the transition between martensite variants. The model calculations are compared with experimental results on Ni-Mn-Ga single crystals.
Twinning Behaviour of Textured Polycrystalline Ni-Mn-Ga Alloy after Hot Extrusion
Authors: Chulist Robert , Böhm Andrea , Lippmann Thomas , Skrotzki Werner , Drossel Welf Guntram , Neugebauer Reimund
Published: December 2009

Up to now most of the research on Ni-Mn-Ga alloys was concentrated on single crystals. However, there is a great interest in polycrystals for technical applications. Recently, polycrystalline Ni50Mn29Ga21 rods of 25 mm diameter and 400 mm length were prepared by hot extrusion. The <100> <110> double fibre texture of the extruded rods was measured with high-energy synchrotron radiation. The microstructure after hot extrusion was analyzed with electron backscatter diffraction. Within the recrystallized grains all three martensitic variants have developed during cooling. Variants with twin boundaries preferentially aligned along the extrusion direction predominate.
Structural, Thermal and Magnetic Properties of Ga Excess Ni-Mn-Ga
Authors: Singh Sanjay , Bhardwaj S. , Panda A.K. , Ahire V.K. , Mitra Amitava , Awasthi A.M. , Barman S.R.
Published: December 2009

The martensitic transition and the ferro- to paramagnetic transition have been studied in a series of Ga excess Ni-Mn-Ga specimens [Ni2-xMnGa1+x (0.4≤ x≤ 0.9)] by differential scanning calorimetry and magnetization measurements. The martensitic transition exhibits a hysteresis whose width is similar to Ni2MnGa, indicating that the transition is thermoelastic. The latent heat of transformation is comparable with other Ni-Mn-Ga alloys. A substantial increase in the martensitic transition temperature is observed due to Ga doping. Interestingly, the x-ray diffraction pattern of all the compositions studied show a modulated martensitic structure in the martensitic phase.
Positron Annihilation Spectroscopy Study of NiMnGa Modulated and Non-Modulated Martensitic Phases
Authors: Merida David , García Jose Angel , Apiñaniz Estibalitz , Plazaola Fernando , Sánchez-Alarcos Vicente , Pérez-Landazábal José Ignacio , Recarte Vicente
Published: December 2009

We have studied by means of positron lifetime measurements the role that vacancy type defects play in the martensitic transformation in magnetic Ni-Mn-Ga shape memory alloys. The measurements presented in this work have been performed in two ternary alloys transforming to modulate and non-modulated martensitic phases. Positron experiments have been realized at room temperature after subsequent isochronal heating at different temperatures up to a maximum temperature of 600°C. Positron results show a large variation of the average lifetime value with the isochronal annealing temperature in non-modulated samples. However, the response in the modulated samples is quite different. These results obtained in both samples are discussed in term of different type of positrons trapping defects and their evolution with the annealing temperature. They have also been compared with Differential Scanning Calorimetry experiments performed in the same samples. The work states the clear influence of the vacancy concentration on the martensitic transformations of these alloys.
Domain Structures across the Martensitic Transformation in Ni2+xMn1-xGa
Authors: Jain Deepti , Banik Soma , Sharath Chandra L.S. , Barman S.R. , Nath R. , Ganesan V.
Published: December 2009

Evolution of domain structures across the martensitic transition (Tm) in the ferromagnetic shape memory alloy system Ni-Mn-Ga is studied using an optical microscope with a temperature variation. Compositions chosen have Tm < Tc, Tm = Tc and Tm > Tc, (Tc=Curie temperature) so that one can compare the nature of martensitic domains. There are no appreciable domain structures when Tm < Tc as compared to the one with Tm > Tc. However, giant morphological changes in the form of appearance of well-developed domains that are propagating with different directions are seen for the composition in which Tm=Tc. The results are discussed in the light of Magnetic Force Microscopy observations as well as giant entropy changes known to occur on samples with co-occurrence of Tm and Tc.
Annealing Effect on Martensitic Transformation and Magneto-Structural Properties of Ni-Mn-In Melt Spun Ribbons
Authors: Sánchez T. , Sánchez Llamazares José Luis , Hernando B. , Santos J.D. , Sánchez M.L. , Perez M.J. , Suñol Joan Josep , Sato Turtelli Reiko , Grössinger Roland
Published: December 2009

We report the effect of a short-time vacuum annealing (1073 K during 10 minutes) on structural phase transition temperatures and magneto-structural properties of as-quenched ribbons of the Heusler alloy Ni50.6Mn34.5In14.9. This alloy crystallizes in a single phase cubic B2-type austenite with a Curie point of TCA=284 K that with the lowering in temperature transforms into a martensite with TCM185 K. The direct and reverse martensitic phase transition temperatures were MS=257 K, Mf = 221 K, AS = 239 K, and Af = 266 K. After annealing austenite shows the highly ordered L21-type structure while the average chemical composition as well as the structural and magnetic transition temperatures were shifted to Ni50.2Mn34.3In15.5 and MS = 253 K, Mf = 238 K, AS = 257 K, Af = 265 K, ΔT = 13 K, TCA = 299 K and TCM207 K. In the annealed samples the magnetization changes associated to the magnetic and structural transitions are more abrupt and magnetization isotherms in both the austenitic and martensitic existence region show higher initial magnetic susceptibility and faster approach to saturation. Field-cooled hysteresis loops at 10 K were shifted along the negative H-axis for both samples, but a significant anomaly was evident on the left side of the hysteresis loop for as-quenched ribbons.
Preparation of Proteins and Peptides for Mass Spectrometry Analysis in a Bottom‐Up Proteomics Workflow
Authors: Gundry Rebekah L. , White Melanie Y. , Murray Christopher I. , Kane Lesley A. , Fu Qin , Stanley Brian A. , Van Eyk Jennifer E.
Published: December 2009

This unit outlines the steps required to prepare a sample for MS analysis following protein separation or enrichment by gel electrophoresis, liquid chromatography, and affinity capture within the context of a bottom‐up proteomics workflow in which the protein is first broken up into peptides, either by chemical or enzymatic digestion, prior to MS analysis. Also included are protocols for enrichment at the peptide level, including phosphopeptide enrichment and reversed‐phase chromatography for sample purification immediately prior to MS analysis. Finally, there is a discussion regarding the types of MS technologies commonly used to analyze proteomics samples, as well as important parameters that should be considered when analyzing the MS data to ensure stringent and robust protein identifications and characterization. Curr. Protoc. Mol. Biol. 88:10.25.1‐10.25.23. © 2009 by John Wiley & Sons, Inc.
In Vitro Selection of RNA Aptamers to a Protein Target by Filter Immobilization
Authors: Hall Bradley , Arshad Seyed , Seo Kyunghyun , Bowman Catherine , Corley Meredith , Jhaveri Sulay D. , Ellington Andrew D.
Published: December 2009

This unit describes the selection of aptamers from a pool of single‐stranded RNA by binding to a protein target. Aptamers generated from this selection experiment can potentially act as protein function inhibitors, and may find applications as therapeutic or diagnostic reagents. A pool of dsDNA is used to generate an ssRNA pool, which is mixed with the protein target. Bound complexes are separated from unbound reagents by filtration, and the RNA:protein complexes are amplified by a combination of reverse transcription, PCR, and in vitro transcription.Curr. Protoc. Mol. Biol. 88:24.3.1‐24.3.27. © 2009 by John Wiley & Sons, Inc.
Evaluation of the Mitochondrial Respiratory Chain and Oxidative Phosphorylation System Using Blue Native Gel Electrophoresis
Authors: Díaz Francisca , Barrientos Antoni , Fontanesi Flavia
Published: December 2009

The oxidative phosphorylation (OXPHOS) system consists of five multimeric complexes embedded in the mitochondrial inner membrane. They work in concert to drive the aerobic synthesis of ATP. Mitochondrial and nuclear DNA mutations affecting the accumulation and function of these enzymes are the most common cause of mitochondrial diseases and have also been associated with neurodegeneration and aging. For this reason, several approaches for the assessment of the OXPHOS system enzymes have been progressively developed. Based on methods described elsewhere, the use of blue native gel electrophoresis (BNGE) techniques to routinely assess the OXPHOS system and screen for enzymatic defects in homogenates or mitochondrial preparations from tissues or cultured cells is described here. Curr. Protoc. Hum. Genet. 63:19.4.1‐19.4.12. © 2009 by John Wiley & Sons, Inc.
Measurement of Molecular Mobility with Fluorescence Correlation Spectroscopy
Authors: Vámosi György , Damjanovich Sándor , Szöllősi János , Vereb György
Published: December 2009

Fluorescence correlation spectroscopy (FCS) is a fluctuation method established three decades ago, whose application to cellular systems became popular in the last decade. Fluctuations of fluorescence emission are observed from a small, femtoliter to sub‐femtoliter, usually confocal volume at high time resolution. A time‐dependent autocorrelation function is generated and evaluated to obtain time constants of photophysical and photochemical reactions, as well as of molecular diffusion and in the observation volume. Molecules in various subcellular compartments—including the nucleus, the cytoplasm, and the membrane—can be observed after labeling them with antibodies, ligands, or fluorescent proteins. The anomaly of diffusion, the local concentration, and the average fluorescence per diffusing particle can also be determined, all of which can be characteristic of molecular interactions. A two‐color version of FCS, fluorescence cross‐correlation spectroscopy, can also be applied to observe co‐diffusion, i.e., stable association of two distinct molecular species in their cellular environment. Curr. Protoc. Cytom. 50:2.15.1‐2.15.19. © 2009 by John Wiley & Sons, Inc.
Total Internal Reflection Fluorescence (TIRF) Microscopy
Authors: Fish Kenneth N.
Published: December 2009

Total internal reflection fluorescence (TIRF) microscopy (TIRFM) is an elegant optical technique that provides for the excitation of fluorophores in an extremely thin axial region (“optical section”). The method is based on the principle that when excitation light is totally internally reflected in a transparent solid (e.g., coverglass) at its interface with liquid, an electromagnetic field, called the evanescent wave, is generated in the liquid at the solid‐liquid interface and is the same frequency as the excitation light. Since the intensity of the evanescent wave exponentially decays with distance from the surface of the solid, only fluorescent molecules within a few hundred nanometers of the solid are efficiently excited. This unit will briefly review the history, optical theory, and different hardware configurations used in TIRFM. In addition, it will provide experimental details and methodological considerations for studying receptors at the plasma membrane in neurons. Curr. Protoc. Cytom. 50:12.18.1‐12.18.13. © 2009 by John Wiley & Sons, Inc.
Introduction to Measurement Theory and Philosophy
Authors: Finkelstein Ludwik
Published: December 2009

The article presents an informal definition of measurement and discusses the concepts on which the definition is based. It outlines the historical development of the theory of measurement from its origins to the present day. It discusses the nature and properties of measurement, which give it its power and usefulness, and compares and contrasts measurement with other forms of description.
Signals, Information and Knowledge, and Meaning
Authors: Yang Qing Ping
Published: December 2009

As the purpose of measurement is acquisition of information and knowledge about the observed system, measurement may be viewed as part of a human cognition process. It involves both human and machine perceptions through direct and indirect experiences. This article examines basic elements and processes of measurement, that is, signal, data, information, and knowledge. It further discusses relevant cognitive issues, and relationships between human and machine perceptions and between direct and indirect experiences.
Models of the Sensor Interface
Authors: Yang Qing Ping
Published: December 2009

Models are increasingly used as important tools for understanding, description, analysis and design of the measurement system interface. This section examines different approaches and types of models and their characteristics. Practical aspects of sensor interface modeling are discussed, together with theoretical issues, for example, set theoretical expression, semiotics, and level of abstraction.
Nature and Scope of Closed‐loop Systems
Authors: Sydenham Peter H.
Published: December 2009

Measuring sensors are important in the formation of closed‐loop control applications; they often use feedback in their own internal operation. Control engineering techniques are also used to improve the response time of actuators and sensors. Whereas most of modern control is implemented in the digital signal domain the underlying principles and methods used are still those originally developed for analog signal systems. This article deals with a brief history of feedback control; an intuitive study of a controller; how a mathematical model is developed for a closed‐loop system; how some common control systems limitation are handled; and the nature of closed‐loop setups in measuring systems.
Principles of Epistemology as Related to Measurement
Authors: Ferris Timothy Lindsay John
Published: December 2009

Epistemology is the branch of philosophy that is devoted to the study of the nature of knowing and knowledge. Concerns of epistemology include how it is possible to know anything, and to have certainty that what one apprehends is as it appears to be. Epistemology differs from ontology in that ontology concerns understanding what things are rather than how they are experienced and known. Epistemology is relevant to the study of measurement because measurement is the process of gaining knowledge of some aspect of things or phenomena through application of appropriate instruments.
Signals in the Time Domain
Authors: Woschni Eugen Georg
Published: December 2009

Signals can be mathematically described either in the frequency or in the time domain. Principal methods using the time domain are described here. Beginning with mean values, the generalization of the mean square value—known as
correlation function
—is introduced. This function is related to the power density function of the Wiener–Chinchine theorem. Practical investigations with examples of mean value and correlation functions are provided.
Statistical Signal Representations
Authors: Woschni Eugen Georg
Published: December 2009

All nondeterministic signals, which means stochastic signals, can be described by means of statistical characteristics. In this article, as well as in the fundamental definitions, for instance, probability functions as the relations to mean values, practical applications and examples are treated.
Systems in the Frequency Domain
Authors: Woschni Eugen Georg
Published: December 2009

Systems can be described either in the time or in the frequency domains. Here methods using the frequency domain are treated, namely, frequency response, their representations as well as their relationships to the differential equation and the logarithmic characteristics of these leading to the Bode plot representation, transfer function, poles and zeros, and root locus representation. A typical simple example is given.
Modulation Theory
Authors: Woschni Eugen Georg
Published: December 2009

An introductory survey on the purposes and methods of modulation and demodulation are given. Two important examples from applied measurement practice are discussed to illustrate practical realization and aspects of the spectra at various places in the system.
Characteristics of Data, Information, Knowledge, and Wisdom
Authors: Ferris Timothy Lindsay John
Published: December 2009

This article provides a definition and a discussion about each of data, information, knowledge, and wisdom in the application of each term to measurement systems. The distinction between these elements in the representation of things is valuable because it assists one's thinking about the nature of the representation of observed phenomena that is available when the representation is available at one of these levels of a hierarchy of representation. The last section discusses the relationship between these elements. The purpose of this article is to enhance the reader's understanding of the issues introduced by the distinction between the elements, and thereby to improve the thinking of the reader when applying that understanding to particular cases.
Terminology and Classification of Measurement Systems
Authors: Sydenham Peter H.
Published: December 2009

This article is the starting point for those unsure about how to get started with a search. It discusses the difficulties that are faced when seeking published materials on measurement‐related topics. An example is given, showing how a topic can be placed in different places in the literature. Also given are lists of synonyms for ‘measuring’, keywords, Dewey index numbers where measurement will be found, and journal names for commonly seen measurement reports.
Cracking Process
Authors:   Technical Staff
Published: December 2009

Thermal Cracking

Fluid Catalytic Cracking

Hydrocracking

Editor's Addendum
Quinolines and Isoquinolines
Authors: Finley K. Thomas
Published: December 2009

Comparative Properties

Quinoline

Isoquinoline
Rare‐Earth Elements and Metals
Authors: Gschneidner K. A. , Evans B.
Published: December 2009

Metallurgical Uses

Occurrence
Genetically Engineered Phage Fibers and Coatings for Antibacterial Applications
Authors: Mao Joan Y. , Belcher Angela M. , Van Vliet Krystyn J.
Published: December 2009

Multifunctionality can be imparted to protein‐based fibers and coatings via either synthetic or biological approaches. Here, potent antimicrobial functionality of genetically engineered, phage‐based fibers and fiber coatings, processed at room temperature, is demonstrated. Facile genetic engineering of the M13 virus (bacteriophage) genome leverages the well‐known antibacterial properties of silver ions to kill bacteria. Predominant expression of negatively charged glutamic acid (E3) peptides on the pVIII major coat proteins of M13 bacteriophage enables solution‐based, electrostatic binding of silver ions and subsequent reduction to metallic silver along the virus length. Antibacterial fibers of micrometer‐scale diameters are constructed from such an E3‐modified phage via wet‐spinning and glutaraldehyde‐crosslinking of the E3‐modified viruses. Silverization of the free‐standing fibers is confirmed via energy dispersive spectroscopy and inductively coupled plasma atomic emission spectroscopy, showing ∼0.61 µg cm−1 of silver on E3–Ag fibers. This degree of silverization is threefold greater than that attainable for the unmodified M13–Ag fibers. Conferred bactericidal functionality is determined via live–dead staining and a modified disk‐diffusion (Kirby–Bauer) measure of zone of inhibition (ZoI) against Staphylococcus epidermidis and Escherichia coli bacterial strains. Live–dead staining and ZoI distance measurements indicate increased bactericidal activity in the genetically engineered, silverized phage fibers. Coating of Kevlar fibers with silverized E3 phage exhibits antibacterial effects as well, with relatively smaller ZoIs attributable to the lower degree of silver loading attainable in these coatings. Such antimicrobial functionality is amenable to rapid incorporation within fiber‐based textiles to reduce risks of infection, biofilm formation, or odor‐based detection, with the potential to exploit the additional electronic and thermal conductivity of fully silverized phage fibers and coatings.
Modeling of partial oxidation in gas–solids downer reactors
Authors: Vaishali S. , Roy Shantanu , Mills Patrick l.
Published: December 2009

Selective partial oxidations represent an important class of reactions in the process industry. Of particular interest is the partial oxidation of n‐butane to maleic anhydride (MAN), which is arguably the largest commercialized alkane partial oxidation process. Partial oxidation of n‐butane, which uses vanadium phosphorous oxide (VPO) as a heterogeneous catalyst, is believed to operate through a unique mechanism in which lattice oxygen oxidizes n‐butane selectively to MAN. Past work has shown that performing partial oxidation reactions in gas–solids riser configuration is realizable and commercially viable, which has lead to commercialization of this technology in the last decade. Though the riser configuration allows optimal and independent control of the oxidation and reduction steps, the riser unit suffers from solid backmixing at walls, which in turn result into lower conversion, nonoptimal selectivity and diminished overall yield of desired product. In recent years, there has been growing interest in downers involving cocurrent downflow of both solids and gas phases, hence offering relatively uniform flow characteristics. In this contribution, we explore through modeling the implications of effecting partial oxidation reactions in a downer (gas–solids cocurrent downflow) compared to that in a conventional riser reactor (gas–solids cocurrent up flow) operated under equivalent operating conditions. Further, we explore the operational space of downers for these reactions, suggesting ways for improving the productivity of downer for partial oxidation applications. © 2009 American Institute of Chemical Engineers AIChE J, 2010
Treatment‐induced diabetic neuropathy: A reversible painful autonomic neuropathy
Authors: Gibbons Christopher H. , Freeman Roy
Published: December 2009

Objective

To describe the natural history, clinical, neurophysiological, and histological features, and outcomes of diabetic patients presenting with acute painful neuropathy associated with glycemic control, also referred to as insulin neuritis.

Methods

Sixteen subjects presenting with acute painful neuropathy had neurological and retinal examinations, laboratory studies, autonomic testing, and pain assessments over 18 months. Eight subjects had skin biopsies for evaluation of intraepidermal nerve fiber density.

Results

All subjects developed severe pain within 8 weeks of intensive glucose control. There was a high prevalence of autonomic cardiovascular, gastrointestinal, genitourinary, and sudomotor symptoms in all subjects. Orthostatic hypotension and parasympathetic dysfunction were seen in 69% of subjects. Retinopathy worsened in all subjects. Reduced intraepidermal nerve fiber density (IENFD) was seen in all tested subjects. After 18 months of glycemic control, there were substantial improvements in pain, autonomic symptoms, autonomic test results, and IENFD. Greater improvements were seen after 18 months in type 1 versus type 2 diabetic subjects in autonomic symptoms (cardiovascular p < 0.01; gastrointestinal p < 0.01; genitourinary p < 0.01) and autonomic function tests (p < 0.01, sympathetic and parasympathetic function tests).

Interpretation

Treatment‐induced neuropathy is characterized by acute, severe pain, peripheral nerve degeneration, and autonomic dysfunction after intensive glycemic control. The neuropathy occurred in parallel with worsening diabetic retinopathy, suggesting a common underlying pathophysiological mechanism. Clinical features and objective measures of small myelinated and unmyelinated nerve fibers can improve in these diabetic patients despite a prolonged history of poor glucose control, with greater improvement seen in patients with type 1 diabetes. ANN NEUROL 2010;67:534–541
Genetically Engineered Mesenchymal Stem Cells: The Ongoing Research for Bone Tissue Engineering
Authors: Hong Dun , Chen Hai‐Xiao , Ge Renshan , Li Ji‐Cheng
Published: December 2009

Bone grafting is crucial in the surgical treatment of bone defects and nonunion fractures. Autogenous bone, allogenous bone, and biomaterial scaffold are three main sources of bone grafts. The biomaterial scaffold, both natural and synthetic, is widely accessible but weak in osteogenic potential. One approach to solve this problem is cell‐based bone tissue engineering (BTE), established by growing living osteogenic cells on scaffold in vitro to build up its osteoinducitive capability. Mesenchymal stem cell (MSC) is suitable for use in cell‐based BTE, but it remains a considerable challenge to induce MSCs to form solely bone and while preventing MSCs from differentiating into fats, muscles, and possibly neural elements in vivo. Recently, there is a drastic rise in use of genetically engineered MSCs, which can secrete growth factors or alter the transcription level, leading to osteoblast lineage commitment, bone formation, fracture repair, and spinal fusion. In this article, we reviewed the literatures regarding applications of genetically engineered MSCs in BTE. We addressed the currently applicable genes and candidate genes for MSCs modification, transduction efficiency and safety issues of the transfect vectors, and administration routes, and we briefly described in vivo tracking and potential clinical application of the genetically modified MSCs in BTE. Anat Rec, 2010. © 2009 Wiley‐Liss, Inc.
A choice prediction competition: Choices from experience and from description
Authors: Erev Ido , Ert Eyal , Roth Alvin E. , Haruvy Ernan , Herzog Stefan M. , Hau Robin , Hertwig Ralph , Stewart Terrence , West Robert , Lebiere Christian
Published: December 2009

Erev, Ert, and Roth organized three choice prediction competitions focused on three related choice tasks: One shot decisions from description (decisions under risk), one shot decisions from experience, and repeated decisions from experience. Each competition was based on two experimental datasets: An estimation dataset, and a competition dataset. The studies that generated the two datasets used the same methods and subject pool, and examined decision problems randomly selected from the same distribution. After collecting the experimental data to be used for estimation, the organizers posted them on the Web, together with their fit with several baseline models, and challenged other researchers to compete to predict the results of the second (competition) set of experimental sessions. Fourteen teams responded to the challenge: The last seven authors of this paper are members of the winning teams. The results highlight the robustness of the difference between decisions from description and decisions from experience. The best predictions of decisions from descriptions were obtained with a stochastic variant of prospect theory assuming that the sensitivity to the weighted values decreases with the distance between the cumulative payoff functions. The best predictions of decisions from experience were obtained with models that assume reliance on small samples. Merits and limitations of the competition method are discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Optimal designs for estimating the parameters in weighted power‐mean‐mixture models
Authors: Coetzer R. L. J. , Focke W. W.
Published: December 2009

In the mixing of fluids, a mixture may be viewed conceptually as a hypothetical collection of fluid clusters. In this context, a mixture model is defined by prescriptions for (a) estimating fluid cluster properties and (b) combining them to yield an overall mixture property. A particular flexible form is obtained from using generalized weighted‐power‐means with the weighting based on global mole fractions${{x}_{i}, 0 \leq {{x}}_{{i}} \leq 1, \sum_{{i}} {{x}}_{{i}}=1, {{i}}=1,2,\ldots,{{q}}}$. Optimal designs for estimating the parameters in SchefféS‐ andK‐polynomials are well known. In this paper, we present optimal designs for estimating the parameters in the generalized weighted‐power‐mean mixture models, which may be nonlinear in the pure and binary interaction parameters. We illustrate the practical value of applying optimal designs for mixture variables through design efficiencies. The designs are derived for modeling viscosity from three‐component mixtures. Copyright © 2009 John Wiley & Sons, Ltd.
PPh3‐Catalyzed Reactions of Alkyl Propiolates with N‐Tosylimines: A Facile Synthesis of Alkyl 2‐[aryl(tosylimino)methyl]acrylate and an Insight into the Reaction Mechanism
Authors: Liu Huimin , Zhang QiongMei , Wang Limin , Tong Xiaofeng
Published: December 2009

A new PPh3‐catalyzed synthesis of alkyl 2‐[aryl(tosylimino)methyl]acrylates from propiolate and N‐tosylimine has been developed. Deuterium‐labelling experiments show that the reaction mechanism involves several hydrogen‐transfer processes, which are not the turnover‐limiting step and strongly rely on the nature of the reaction media. The stable phosphonium–enamine zwitterion, which was proven to play an important role in the catalytic cycle, has been isolated and characterised by X‐ray analysis.
Plasma N‐Terminal Protype‐B Natriuretic Peptide and Restrictive Mitral Flow to Risk‐stratify Patients with Stage B Heart Failure
Authors: Dini Frank L. , Whalley Gillian , Poppe Katrina , Fontanive Paolo , Rosa Gian Marco , Doughty Robert N. , Bello Vitantonio Di
Published: December 2009

Background

The prognostic role of echocardiography is well established in patients with previous or current symptoms of heart failure (HF). Less is understood about patients with stage B HF, who have structural heart disease but no symptoms at any stage. This study investigated the role of plasma N‐terminal protype‐B natriuretic peptide (NT‐proBNP) and Doppler‐echo parameters of diastolic and systolic function for risk stratification in stage B HF patients.

Hypothesis

We investigated whether plasma NT‐proBNP and Doppler‐echo parameters of diastolic and systolic function have a role in risk stratification of stage B HF patients.

Methods

Doppler echocardiography was performed in 155 outpatients with asymptomatic left ventricular (LV) dysfunction (ejection fraction [EF] < 50%) and comprised conventional diastolic variables, including pulsed‐Doppler mitral E‐wave deceleration time (EDT). Plasma NT‐proBNP was assessed at the time of the echocardiogram. The prespecified end point was cardiac death or HF hospitalization or any new HF episode requiring a change in medication.

Results

Mean EF was 35% ± 7%. Median NT‐proBNP was 745 pg/mL (interquartile range [IQR], 442–1672). Patients with events at follow‐up (n = 46) had higher prevalence of risk factors for developing HF. Plasma NT‐proBNP, EDT, and EF were independently associated with cardiac events at multivariable analysis and receiver operating characteristic curves were used to determine the optimal prognostic cut points for each: NT‐proBNP ≥ 831 pg/mL, EDT < 145 msec, and EF < 37%. When used in combination, event‐free survival was incrementally worse with each additional abnormality.

Conclusion

Plasma NT‐proBNP, EDT, and EF are independently useful for prognostic stratification of stage B HF patients and suggest an incremental prognostic deficit is associated with the combination of each. This study supports the complementary role of comprehensive echocardiography and natriuretic peptide assay in asymptomatic LV dysfunction. Copyright © 2009 Wiley Periodicals, Inc.