bluuebunny/crossref_metadata_2025 huggingface dataset:
Living technology today and tomorrow
Authors: Bedau Mark A
Published: November 2009

The concept of living technology can be applied to any technology that is powerful and useful specifically because it has some of the fundamental features of living systems. This article is a brief general overview of living technology's current state and projected future. After illustrating
living technology and discussing why it is complicated to define, I explain how it is related to so-called NBIC convergence (see below) and discuss some of the larger social, ethical and aesthetic issues that it raises.
Introduction: Living Buildings: Plectic Systems Architecture
Authors: Ascott Roy
Published: November 2009

The journal welcomes theorists and practitioners, working at the leading edge of their field, to guest-edit issues of the journal. In this present case, we are delighted to have secured the collaboration of Professor Neil Spiller and Doctor Rachel Armstrong of the Bartlett. I wish to
thank them both, and their selected authors, for the originality and scope of the articles here assembled.
Living buildings: plectic systems architecture
Authors: Armstrong Rachel
Published: November 2009

Modern building practices rely on Victorian construction methods founded on industrial technologies. This article asks how it may be possible to develop an alternative approach to the construction of our homes and cities that is more environmentally responsive, works with the natural
energy flows within matter and which is connected to natural systems, not insulated from them. The approach of plectic systems architecture suggests that it is possible to create living buildings by re-examining the dynamics of terrestrial matter through a new approach to materials science
and computation to engage in a fundamental re-visioning of what constitutes an architectural practice for the twenty-first century.
Fire Performance Testing of Building Element Interfaces and Connections
Authors: Parker Arthur J. , Iwankiw Nestor R.
Published: November 2009

The minimum fire-resistance ratings for vertical and horizontal assemblies and structural members are provided in the prescriptive requirements of the building codes. National and international test methods have been developed to provide a standardized means for evaluating the performance of these building elements. Building elements such as horizontal assemblies (floors), vertical assemblies (walls), and structural members (beams and columns) are generally tested as discrete elements. In an actual building, the walls intersect with the floors and beams and girders are connected to columns. In light of recent high-profile fire events, the fire community has been questioning if these connections and interfaces are being properly tested and evaluated. In an actual building, these building elements are interconnected, and their performance is affected by all elements that comprise the building structure during a real fire event. This paper will review common structural building interface and connection construction features, how they are currently being evaluated, and how their large-scale fire performance evaluations can be conducted. The results of the testing of a simulated wall/floor assembly interface assembly will be presented to highlight one potential means for testing these features along with the limitations mainly due to the available test equipment.
The Relationship Between General Population Suicide Rates and Educational Attainment: A Cross‐National Study
Authors: Shah Ajit , Bhandarkar Ritesh
Published: November 2009

Suicides are associated with both high and low levels of intelligence and educational attainment in both individual‐level and aggregate‐level studies. A cross‐national study examining the relationship between general population suicide rates (y) and educational attainment (x) was undertaken with the a priori hypothesis that the relationship would be curvilinear and follow a U‐shaped curve with the quadratic equation Y = A + BX + CX2, where A, B, and C are constants. Data on suicide rates and the Education Index (a proxy measure of educational attainment) were ascertained from the World Health Organization and the United Nations Web sites, respectively. The main finding was the predicted curvilinear relationship between general population suicide rates, in both sexes, and the Education Index fit the above quadratic equation. Given the cross‐sectional study design, a causal relationship cannot be assumed. The impact of educational attainment on general population suicide rates may occur through interaction with other factors, mediation of the effects of other factors, or by its effects being mediated by other factors, and require further study.
Mental Disorders and Socioeconomic Status: Impact on Population Risk of Attempted Suicide in Australia
Authors: Page Andrew , Taylor Richard , Hall Wayne , Carter Gregory
Published: November 2009

The population attributable risk (PAR) of mental disorders compared to indicators of socioeconomic status (SES) for attempted suicide was estimated for Australia. For mental disorders, the highest PAR% for attempted suicide was for anxiety disorders (males 28%; females 36%). For SES, the highest PAR% for attempted suicide in males was for occupation (males 31%; females 16%) and education level (males 19%; females 8%), following adjustment for age and mental disorders. The study results suggest that one third of suicide attempts in both males and females are attributable to anxiety disorders, the same proportion attributable to low educational or occupational status.
An Inquiry into Relationship Suicides and Reciprocity
Authors: Davis Mark S. , Callanan Valerie J. , Lester David , Haines Janet
Published: November 2009

Few theories on suicide have been grounded in the norm of reciprocity. There is literature on suicide, however, describing motivations such as retaliation and retreat which can be interpreted as modes of adaptation to the norm of reciprocity. We propose a reciprocity‐based theory to explain suicides associated with relationship problems. Employing a content analysis of suicide notes, we tested the theory, finding evidence of exploitation, exploiter guilt, retaliation, and retreat as motives for committing relationship‐based suicide. Reciprocity‐based note writers were more likely to have used alcohol or drugs in the hours prior to committing suicide, and they were also more likely to have made their intentions known beforehand. Implications for future research as well as for suicide prevention are discussed.
Comparing Cognitive Behavior Therapy, Problem Solving Therapy, and Treatment as Usual in a High Risk Population
Authors: Stewart Carment D. , Quinn Andrea , Plever Sally , Emmerson Brett
Published: November 2009

Cognitive behavior therapy (CBT), problem‐solving therapy (PST), or treatment as usual (TAU) were compared in the management of suicide attempters. Participants completed the Beck Hopelessness Scale, Beck Scale for Suicidal Ideation, Social Problem‐Solving Inventory, and Client Satisfaction Questionnaire at pre‐ and posttreatment. Both CBT and PST indicated significant improvements over time within the majority of measured variables; when compared to TAU, both groups showed significant differences on satisfaction. When PST was compared to TAU, results indicated significant differences on suicidal ideation, indicating overall efficacy of brief therapies with suicide attempters.
A Comparison of Suicide Note Writers with Suicides Who Did Not Leave Notes
Authors: Callanan Valerie J. , Davis Mark S.
Published: November 2009

There is disagreement in the suicide literature on the value of suicide notes as a data source, particularly regarding the extent to which suicide decedents who write notes differ from those who do not. Using 10 years of suicide cases from Summit County, Ohio, these two groups were compared on 40 variables including sociodemographic characteristics, reported affect before death, precipitating events, physical and mental health status and care, and method of suicide. The only differences found were that note writers were more likely to have lived alone and had made prior suicide threats. These findings suggest that for research purposes, suicide cases with and without notes are essentially similar.
Investigation of K to L shell/subshell vacancy transitions of Zn and Fe in Fe
x
Zn1-x
thin film alloys
Authors: Sögüt Ö.
Published: November 2009

The vacancy transfer probabilities from K-shell to L
2-, L
3- and L-shell/subshells were measured in Fe
x
Zn1-x
thin film alloys. The samples were excited by γ photons with energy 59.5 keV from a 50 mCi 241Am radioisotope source. The emitted K X-rays were detected by an Ultra-LEGe having a resolution of 150 eV at 5.9 keV. For comparison with experimental results, theoretical calculations have been made using radiative and nonradiative transition rates. The measured results are in good agreement with theoretically calculated values within experimental errors. Fe
x
Zn1-x
thin film alloys were electrochemically deposited on aluminum substrates from sulfate bath. In conclusion, it was found that the vacancy transfer probabilities changed in Fe
x
Zn1-x
thin films for different compositions of x.
Radiosynthesis of a novel potential adenosine A3 receptor ligand, 5-ethyl 2,4-diethyl-3-((2-[18F]fluoroethyl)sulfanylcarbonyl)-6-phenylpyridine-5-carboxylate ([18F]FE@SUPPY:2)
Authors: Haeusler Daniela , Mitterhauser Markus , Mien Leonhard-Key , Shanab K. , Lanzenberger Rupert , Schirmer E. , Ungersboeck J. , Nics L. , Spreitzer H. , Viernstein H. , Dudczak Robert , et al.
Published: November 2009

Since, to date very limited information on the distribution and function of the adenosine A3 receptor is available, the development of suitable radioligands is needed. Recently, we introduced [ 18F]FE@SUPPY (5-(2-[ 18F]fluoroethyl) 2,4-diethyl-3-(ethylsulfanylcarbonyl)-6-phenylpyridine-5-carboxylate) as the first PET-ligand for the A3R. Regarding the metabolic profile – this class of dialkylpyridines comprises two ester functions within one molecule, one carboxylic and one thiocarboxylic – one could expect carboxylesterases significantly contributing to cleavage and degradation. Therefore, our aim was the development of [ 18F]FE@SUPPY:2 (5-ethyl 2,4-diethyl-3-((2-[ 18F]fluoroethyl)sulfanylcarbonyl)-6-phenylpyridine-5-carboxylate), the functional isomer containing the label at the thiocarboxylic moiety.

For satisfactory yields in high scale radiosyntheses, a reaction temperature of 75 °C has to be applied for at least 20 min using 20 mg/mL of precursor. So far, 6 complete high-scale radiosyntheses were performed. Starting from an average of 51.2±21.8 GBq (mean±SD) [ 18F]fluoride, 5.8±4.1 GBq of formulated [ 18F]FE@SUPPY:2 (12.0±5.4%, based on [ 18F]fluoride, not corrected for decay) were prepared in 75±8 min.
Uranium, plutonium and neptunium co-recovery with high nitric acid concentration in extraction section by simplified solvent extraction process
Authors: Nakahara M. , Sano Y.
Published: November 2009

As a part of NEXT, the behavior of Np in a simplified solvent extraction process using TBP as an extractant for U, Pu and Np co-recovery was investigated. Two approaches to Np co-recovery with U and Pu in the irradiated fast reactor core fuel using a dissolver solution in a counter current were examined. One used a feed solution with a high HNO3 concentration, and the other used a scrubbing solution with a high HNO3 concentration. The leakages of Np to the raffinate were 1.1 and 4.7% using high HNO3 concentration feed and scrubbing solutions, respectively. Simulation results based on these experiments showed that high HNO3 concentration in the feed solution is advantageous for the Np extraction because Np oxidation progresses in the feed solution before being supplied into the centrifugal contactor, and there is less effect of HNO2 at the extraction section.
X-ray absorption spectroscopic study of trivalent and tetravalent actinides in solution at varying pH values
Authors: Brendebach Boris , Banik N. L. , Marquardt Christian M. , Rothe J. , Denecke M. , Geckeis H.
Published: November 2009

We perform X-ray absorption spectroscopy (XAS) investigations to monitor the stabilization of redox sensitive trivalent and tetravalent actinide ions in solution at acidic conditions in a pH range from 0 to 3 after treatment with holding reductants, hydroxylamine hydrochloride (NH2OHHCl) and Rongalite (sodium hydroxymethanesulfinate, CH3NaO3S). X-ray absorption near edge structure (XANES) measurements clearly demonstrate the stability of the actinide species for several hours under the given experimental conditions. Hence, structural parameters can be accurately derived by extended X-ray absorption fine structure (EXAFS) investigations. The coordination structure of oxygen atoms belonging to water ligands surrounding the actinide ions does not change with increasing pH value (approximately 11 O atoms at 2.42 Å in the case of U(IV) at pH 1, 9 O atoms at 2.52 Å for Np(III) at pH 1.5, and 10 O atoms at 2.49 Å for Pu(III) up to pH 3), indicating that hydrolysis reactions are suppressed under the given chemical conditions.
An Elusive Passage of the Earlier Funerary Literature in its Iconographic and Ritual Context
Authors: Goebs Katja
Published: November 2009

Pyr. 398c–399a, which describes the deceased king as seated “with his back to Geb”, is re-examined in relation to its co- and context within the Cannibal Spell, as well as being set against some hitherto overlooked iconographic and textual evidence from other sources. A new interpretation of the passage as relating to the rituals of royal legitimization is proposed.
A Depiction of Paris in Luxor Temple and the “eidolon” of Helen
Authors: Manassa Colleen
Published: November 2009

In the Ramesside court of Luxor Temple is a small depiction of a statue of Paris, placed intentionally opposite a statue of Nefertari, part of a colossus of Ramesses II. The image of Paris represents the only non-literary evidence for the Greek tradition of Helen being in Egypt during the Trojan War and suggests that Graeco-Roman tourists were aware of this alternate version of events. A consideration of this graffito within an art historical context suggests that it might relate to Euphranor’s lost statue of Paris.
A New Royal Name Sealing from Tell Edfu
Authors: Moeller Nadine
Published: November 2009

The recent excavations at Tell Edfu have led to the discovery of a new Middle Kingdom sealing which was found in an administrative building. It shows the standing figure of the king wearing the crown of Upper and Lower Egypt and has a small cartouche in front of his face that can be read as the throne name of Amenemhat III. This is the first time that such a motif has been discovered in a secure late Middle Kingdom context.
Is That a Rhetorical Question? Shipwrecked Sailor (pHermitage 1115), 150 Reconsidered
Authors: Scalf Foy
Published: November 2009

This article examines a difficult passage from the Tale of the Shipwrecked Sailor (pHermitage 1115, 150). Near the end of the story, the official relates the good deeds which will be performed on behalf of the divine snake if he allows the official to return home. The snake’s enigmatic response has provoked a variety of interpretations. It may be possible to resolve the questions surrounding this section of the tale by understanding the passage as a rhetorical question used by the snake to trump the official.
The Forms of the Coptic 2nd Person Feminine Singular Pronouns
Authors: Uljas Sami
Published: November 2009

The present article proposes a new analysis of the form and etymology of the Coptic 2nd person feminine singular suffix and prefix pronouns. It is suggested that in the tripartite conjugation and the conversions of the bipartite conjugation, the said person was expressed by using the bare pre-nominal conjugation base/converter (if such existed separately from the pre-pronominal form). Later, the bases and converters ending with re were reanalysed as consisting of a base + a suffix pronoun re. The rise of this new pronoun can be traced by studying manuscripts covering several centuries of language development. It is also proposed that the creation of the suffix motivated an analogous extension of re into the prefix of the 1st present and future, where the older form te gradually gave way to a new and clearly secondary form ter.
Nearly Constant Loss in Lithium and LiCl-doped Borate Glasses
Authors: Sidebottom D. L , Bassett M.
Published: November 2009

Measurements of the complex dielectric permittivity in (Li2O)x(B2O3)100-x and halide-doped (Li2O)x (LiCl)y(B2O3)100-x-y glasses conducted in the nearly constant loss (NCL) regime at low temperatures are reported. Scaling properties reveal that the NCL in (Li2O)x(B2O3)100-x is largely ionic in origin for these materials and increases in proportion to the Li2O content. However, at low Li2O content, the NCL becomes dominated by a non-ionic loss arising from the borate network or other impurity polarizations. Halide doping is seen to produce an additional enhancement of the NCL that is consistent with its known enhancement of the bulk conduction.
Models for Ion Transport in Amorphous Materials: Recent Advances
Authors: Dieterich Wolfgang , Maass Philipp
Published: November 2009

By the development and investigation of coarse-grained models for ion motion in disordered systems, important progress has been achieved in the past to explain a large variety of ion transport properties in amorphous materials. In this work we discuss recent theoretical advances, which allow one to better understand the nearly constant dielectric loss in disordered solid ionic conductors, the mixed glass former effect in glassy electrolytes, and certain effects of ion motion in polymer electrolytes.
Structural Elucidation of Alkali Fluorozirconate Glasses Using High-Resolution Solid State NMR
Authors: Araujo C. C. de , Bischoff C. , Eckert Hellmut , Buksak A. , Frischat G. H.
Published: November 2009

The structure of two compositional series of ZrF4-LaF3-BaF2-MF (M = Li or Na) glasses has been examined by 19F magic-angle spinning (MAS)-NMR spectroscopy. From a detailed lineshape analysis, the fractions of corner-bridging (CBF) and non-bridging fluoride (NBF) species were extracted. With increasing LiF (or NaF) content, the fraction of NBF increases significantly, producing an increased spectral contribution of the low-frequency lineshape components. 19F{7Li} rotational echo double resonance (REDOR) experiments reveal that this part of the MAS-NMR lineshape interacts most closely with the 7Li nuclei. The compositional dependence of the NBF fractions is discussed in the context of various scenarios, describing the transformation of CBF units into NBF units, and affecting the average coordination number of the Zr ions. The results indicate that the evolution of the NBF fraction cannot be described by a single scenario over the entire composition range.
Nonlinear Conductivity and Permittivity Spectra of Ion Conducting Glasses
Authors: Staesche Halgard , Murugavel Sevi , Roling Bernhard
Published: November 2009

We have measured third-order conductivity and permittivity spectra of a Li2O · Al2O3 · 4 SiO2 glass and of a 0.15 Na2O · 0.85 GeO2 glass by applying ac electric fields up to 100 kV cm−1. For the application of these high fields, the glass samples are interfaced with highly conductive liquid electrolyte solutions. In this field range, the electrical response due to ion dynamics in the bulk of a glass sample is weakly nonlinear, while the electrical reponse due to ion transport across the interface between glass sample and liquid electrolyte is strongly nonlinear. For both glasses, the real part of the third-order conductivity is characterised by a change in sign in a frequency range where the diffusive bulk ion dynamics passes over into the subdiffusive bulk ion dynamics. On the other hand, the real part of the third-order permittivity spectra is characterised by a change in sign at lower frequencies where ion transport across the glass / liquid electrolyte interface passes over into the bulk ion transport. We show that these changes in sign can be rationalised by considering an equivalent circuit for a disordered solid ion conductor interfaced with a highly conductive liquid. In this circuit, the bulk and interfacial resistances are assumed to decrease with increasing voltage.
Physical Chemistry of Solids – The Science behind Materials Engineering: Concepts, Models, Methods
Authors: Janek Jürgen , Martin Manfred , Becker K.D.
Published: November 2009

The role of Physical Chemistry of Solids as origin of many fundamental concepts for modern materials science as also the bridge between physics, chemistry and materials engineering is emphasized and exemplified. The model of the electrical double layer, the concept of point defects in crystals and transport phenomena and reactions in the solid state are discussed as examples.
Electrical Transport in Oxide Glasses Containing Gold Nanoparticles
Authors: Issa Ahmed , Küchler Reiner , Anavekar Rajan V. , Böhmer Roland , Kanert Otmar , Jain Himanshu
Published: November 2009

Gold doped ruby glasses are classical examples of metal-glass nanocomposites that have been investigated for their striking optical properties. For their multifunctional applications, we have explored the nature of the electrical response of two oxide glasses containing a small amount (<0.1mol%) of gold. Gold-doped lithium borate (LBO) and lanthanum borogermanate (LBGO) glasses are studied using ac conductivity as a function of frequency and temperature in relation to their structure as determined by electron microscopy. For ionically conducting LBO, Au doping produces a noticeable increase of the electrical conductivity. For poorly conducting LBGO, gold doping introduces a dielectric loss peak indicative of dipolar relaxation. The heat treatment of both glasses introduces a new mechanism of dc conduction or dipolar loss, which has about one third the activation energy of the untreated samples. This unexpected behavior is attributed to an ionic-to-electronic conductivity transition in gold doped glasses.
Determination of the Parameters that Control Oxidation Using Optical Interference, Applied to the Two Phase Oxide Scale on Copper
Authors: Gil Y. , Riess I.
Published: November 2009

The oxidation of a metal forming a transparent oxide allows it to be followed in situ by optical interference. The layer thickness is determined from the interference pattern. The method can be applied to any tarnishing process as long as the resulting layer stays transparent. Oxidation of copper is followed in air, at T = 230oC, making use of the three colors of a video camera. In this case a two phase, Cu2O|CuO scale is formed on Cu. An analysis of the rate of formation of two layers of two phases is presented. The rate constants are related to a surface reaction rate or to bulk diffusion and conductivity. It is shown that while the total amount of oxide increases with time the layer thickness of one of the phases can temporarily decrease. In the long time limit both layers follow the parabolic law i.e. increase as √time. The method can be applied also to the inverse process of reduction and decrease in the scale thickness.
Crystalline Cation Conductors with Rotational Anion Disorder: Results of Quasielastic Neutron Scattering Experiments on Orthophosphates
Authors: Wilmer Dirk , Meyer Hinrich-Wilhelm
Published: November 2009

Results and interpretations of several quasielastic neutron scattering measurements on samples of the isostructural high-temperature phases of Ag3PO4 and Na3PO4, prominent members of the group of fast cation conducting plastic phases are reported.Time-of-flight experiments reveal details on the phosphate reoriention in Ag3PO4: We find isotropic rotational diffusion. A consistent interpretation of the data suggests that silver ions are involved in the fast anion dynamics, a behaviour which is in line with the displacement of phosphorus detected in earlier neutron diffraction experiments. The reorientation activation energy of 0.17 eV is in the typical range found also in other ion conducting rotor phases.Na3PO4 was examined in time-of-flight and backscattering experiments, differing considerably in the time scale of the detected molecular dynamics. Anion reorientation, observed on the time scale of picoseconds and activated with 0.18 eV, appears as a predominantly circular diffusion with one P–O axis fixed. Our results suggest the involvement of sodium ions in the anion reorientation, i.e., a correlated motion of both types of ions in the picosecond regime.The much slower sodium jump diffusion in Na3PO4 was found to be thermally activated with 0.74 eV. Moreover, we find clear evidence for the predominance of jumps between tetrahedrally co-ordinated cation sites.Quasielastic neutron scattering reveals a wealth of dynamic details on the two high-temperature phases of Na3PO4 and Ag3PO4 which exhibit considerable differences (e.g., in the geometric details of anion dynamics) in spite of their structural similarities. Both plastic phases, however, give evidence of the involvement of cations in the anion dynamics, i.e., in a correlated reorientational motion of cations and anions on the picosecond time scale.
Space Charge Polarization Measurements as a Method to Determine the Temperature Dependence of the Number Density of Mobile Cations in Ion Conducting Glasses
Authors: Martin Steve W. , Yao Wenlong , Berg Kyle
Published: November 2009

A method is proposed using mean-field theories to help solve a long standing problem in the study of ionically solid electrolytes. While it has been long known that the ionic conductivity in solid electrolytes is comprised of two terms, the mobility and number of mobile charge carriers, there has been no accurate method developed to determine these two quantities independently. In this paper, we apply a mean-field method based upon low frequency a.c. impedance measurements of the limiting low frequency space charge polarization capacitance that develops as a result of the mobile carrier population diffusing to blocking electrodes. The space charge capacitance that develops is shown to be a simple function of the number of charge carriers and is found to be independent of the d.c. conductivity, but strongly dependent upon temperature. Measurements on two simple but well studied ion conducting glasses, LiPO3and NaPO3, suggest that the carrier population is thermally activated where only a small fraction of the cations are mobile in the glass. The activation energy for carrier creation in LiPO3is larger (49 kJ/mol) than that for NaPO3glass (44 kJ/mol) and is in agreement with models of activation energies in ion conducting glasses that associate the creation energy with the cation charge density.
The Solid Electrolyte Interphase – The Most Important and the Least Understood Solid Electrolyte in Rechargeable Li Batteries
Authors: Winter Martin
Published: November 2009

In this chapter, the Solid Electrolyte Interphase (SEI) concept is introduced and the different requirements on the electrolyte and on the SEI formation process in the presence of various anode materials (metallic lithium, graphitic carbons, and lithium storage metals/alloys), in particular, similarities and differences, are highlighted. The difficulties to understand and analyze the SEI characteristics and composition are discussed by examples.
A high-strength extruded Mg–Gd–Zn–Zr alloy with superplasticity
Authors: Wu Y.J. , Peng L.M. , Zeng X.Q. , Lin D.L. , Ding W.J.
Published: November 2009

This article presents an extruded Mg–Gd–Zn–Zr alloy produced by conventional ingot metallurgy, exhibiting high-strength and excellent ductility at room and elevated temperatures. The superplastic behavior was observed in the Mg–Gd–Zn (–Zr) alloy at elevated temperatures above 573 K. In the alloy, both the X phase in grain boundaries and the lamellae within matrix have the 14H-type long-period, stacking-ordered structure. It indicates that the X phase and the lamellae within matrix play important roles in the excellent mechanical properties.
Influence of stacking-fault energy on the accommodation of severe shear strain in Cu-Al alloys during equal-channel angular pressing
Authors: An Xianghai , Lin Qingyun , Qu Shen , Yang Gang , Wu Shiding , Zhang Zhe-Feng
Published: November 2009

X-ray diffraction (XRD) and transmission electron microscope (TEM) investigations have been carried out to decode the influence of stacking-fault energy (SFE) on the accommodation of large shear deformation in Cu-Al alloys subjected to one-pass equal-channel angular pressing. XRD results exhibit that the microstrain and density of dislocations initially increased with the reduction in the SFE, whereas they sharply decreased with a further decrease in SFE. By systematic TEM observations, we noticed that the accommodation mechanism of intense shear strain was gradually transformed from dislocation slip to deformation twin when SFE was lowered. Meanwhile, twin intersections and internal twins were also observed in the Cu-Al alloy with extremely low SFE. Due to the large external plastic deformation, microscale shear bands, as an inherent deformation mechanism, are increasingly significant to help carry the high local plasticity because low SFE facilitates the formation of shear bands.
Self-organized nanotubular layer on Ti–4Zr–22Nb–2Sn alloys formed in organic electrolytes
Authors: Liang Yanqin , Yang Xianjin , Cui Zhenduo , Zhu Shengli
Published: November 2009

Self-organized nanotubular layers are electrochemically fabricated on Ti–4Zr–22Nb–2Sn alloys in water/glycerol (volume ratio 1:1) mixtures containing 0.3 M NH4F. Highly ordered nanotubes with two distinct diameters of ∼203 ± 5 (large size) and 113 ± 5 nm (small size) were observed at the bottom of the layer, which may be ascribed to the different microstructure and composition in this alloy. On extended anodization, the small-size tubes gradually disappeared because of the increasing H+. After annealing for 1 h at 500 °C, the nanotube layer on the Ti–4Zr–22Nb–2Sn alloy was transformed from the amorphous phase to anatase. The nanotubes were connected to each other by spaced rings at the sidewalls, whereas the distance between neighboring rings increased with the amplitude of applied current density.
Numerical verification for instrumented spherical indentation techniques in determining the plastic properties of materials
Authors: Zhang Taihua , Jiang Peng , Feng Yihui , Yang Rong
Published: November 2009

Instrumented indentation tests have been widely adopted for elastic modulus determination. Recently, a number of indentation-based methods for plastic properties characterization have been proposed, and rigorous verification is absolutely necessary for their wide application. In view of the advantages of spherical indentation compared with conical indentation in determining plastic properties, this study mainly concerns verification of spherical indentation methods. Five convenient and simple models were selected for this purpose, and numerical experiments for a wide range of materials are carried out to identify their accuracy and sensitivity characteristics. The verification results show that four of these five methods can give relatively accurate and stable results within a certain material domain, which is defined as their validity range and has been summarized for each method.
Effects of homogeneous irradiation of electron beam with low potential on adhesive strength of polymethyl methacrylate composite sheet covered with nylon-6 film
Authors: Nishi Yoshitake , Sato Hironori , Iwata Keisuke , Nishi Yoshitake , Iwata Keisuke
Published: November 2009

By using homogeneous electron-beam (EB) irradiation, rapid adhesion between nylon-6 film and polymethyl methacrylate (PMMA) was successfully developed. Effects of homogeneous irradiation of electron beam with low potential (HIEBL) on adhesive strength of different polymers without glue were investigated. HIEBL less than 0.216MJ kg−1 (MGy) increased the adhesive strength and its strain of composites constructed with nylon-6 film and PMMA, although additional HIEBL at more than 0.432 MGy apparently decreased the adhesive strain. HIEBL less than 0.432 MGy also enhanced the elasticity (dσ/dε)o of composites. To evaluate the influence of HIEBL on the adhesive strength, electron spin resonance signals that relate to dangling bonds were observed. Because EB irradiation generated dangling bonds in polymethyl methacrylate and nylon-6, dangling bonds probably acted reactive and bonding sites to each polymer at interface. Therefore, HIEBL enhanced the adhesive strength as well as elasticity of the composites.
Critical shell thickness and emission enhancement of NaYF4:Yb,Er/NaYF4/silica core/shell/shell nanoparticles
Authors: Qian Li Peng , Yuan Du , Shun Yi Guang , Chow Gan Moog
Published: November 2009

Amorphous silica shells, used for functionalization of inorganic nanoparticles in bioapplications, were coated on chemically synthesized NaYF4:Yb,Er upconversion fluorescent nanoparticles via a reverse microemulsion method by using dual surfactants of polyoxyethylene (5) nonylphenylether and 1-hexanol, and tetraethyl orthosilicate as precursor. NaYF4:Yb,Er nanoparticles were equiaxed with a particle size of 11.1 ± 1.3 nm. The thickness of silica shell was ∼8 nm. NaYF4:Yb,Er/silica core/shell nanoparticles were well dispersed in solvents such as ethanol and deionized water. The emission intensities of NaYF4:Yb,Er/silica core/shell nanoparticles remained the same as that of uncoated nanoparticles after surface functionalization with an amine group using (3-aminopropyl)-trimethoxysilan. Silica, although providing a good barrier to the nonradiative relaxation between the upconversion nanoparticles and the environments, did not enhance the emission intensity of upconversion nanoparticles. To increase the emission intensity of NaYF4:Yb,Er/silica core/shell nanoparticles, an undoped NaYF4 shell (∼3-nm thick) was deposited on the upconversion nanoparticles before the silica coating. The total emission intensity of NaYF4:Yb,Er/NaYF4/silica core/shell/shell nanoparticles increased by 15 times compared to that without the intermediate NaYF4 shell. The critical shell thickness of NaYF4 was ∼3 nm, beyond which no further emission intensity enhancement was observed.
Volatilization of alkali ions and effects of molecular weight of polyvinylpyrrolidone introduced in solution-derived ferroelectric K0.5Na0.5NbO3 films
Authors: Wang Lingyan , Yao Kui , Goh Phoi Chin , Ren Wei
Published: November 2009

Ferroelectric K0.5Na0.5NbO3 (KNN) thin films were prepared by a chemical solution deposition approach with polyvinylpyrrolidone (PVP) of different molecular weights introduced in the precursor solutions. The volatilization of the alkali ions and the effects of the molecular weight of PVP were examined with x-ray diffraction (XRD), thermal analysis, mass spectrometry, and x-ray photoelectron spectroscopy (XPS). The results clearly showed that the volatilization of the alkali ions mainly happened at moderate temperatures before the crystallization of the KNN perovskite phase. Loss of Na was more significant than K ions during the heating process of KNN. The introduction of PVP with the appropriate molecular weight could effectively promote the crystallization of the KNN perovskite phase at reduced temperature and substantially suppress the loss of the alkali ions before crystallization. Therefore, a high dielectric constant, piezoelectric coefficient, and well saturated ferroelectric hysteresis loops were obtained in the KNN films in which PVP of the right molecular weight were introduced.
Analysis of soft impingement in nonisothermal precipitation
Authors: Fan Kai , Liu Feng , Yang Wei , Yang Gencang , Zhou Yaohe
Published: November 2009

The effects of soft impingement on precipitation are considered. A physically realistic analytical treatment of soft impingement has been developed for solid-state precipitation in a nonisothermal heating/cooling process following the basic assumptions (i.e., a two-stage transformation including site saturation of nucleation, isotropic growth and linear approximation for a concentration gradient in front of the precipitate/matrix interface). Furthermore, both one- and three-dimensional precipitations have been described using a compact expression which is analogous to Zener’s model but with a temperature-dependent growth coefficient. A detailed description for the model parameters has been given for the model application. Good agreement with published experimental data, for example, the decomposition of austenite in a 0.038–0.30wt%Mn plain carbon steel, has been achieved.
Enhancement of ductility in Mg–3Al–1Zn alloy with tilted basal texture by electropulsing
Authors: Guan Lei , Tang Guoyi , Chu Paul K. , Jiang Yanbin
Published: November 2009

The microstructure and texture evolution in a cold-rolled AZ31 magnesium alloy during electropulsing treatment (EPT) are investigated and correlated with the mechanical properties. The microstructure is effectively refined, and a tilted basal texture develops gradually during EPT. The yield stress in the treated samples is lower than that in the cold-rolled sample, indicating that texture softening is dominant over strengthening because of grain refinement. The phenomenon is primarily the result of the tilted basal texture. EPT improves the tensile ductility of the EPT samples significantly, albeit slightly compromising the tensile strength. The mechanism of the microstructure evolution during electropulsing is discussed from the viewpoint of grain-boundary motion. Moreover, the ductility enhancement is discussed in terms of the deformation mechanism and texture of the Mg alloy.
Relationship between layered crystal structure and mechanical properties of M3AlN (M = Zr and Hf): A first-principles investigation
Authors: Wang Jiemin , Wang Jingyang , Li Fangzhi , Zhou Yanchun
Published: November 2009

Bonding character, elastic mechanical parameters, ideal strengths, and atomistic shear deformation mechanisms of M3AlN (M = Zr and Hf) were studied by first-principles method. M3AlN exhibits layered chemical bonding character due to the alternately stacking of relatively soft Al–M and strong N–M covalent bonds. The second-order elastic constants and mechanical parameters of M3AlN were reported for the first time. The stress–strain relationships for different deformation modes were studied and the ideal shear and tensile strength were obtained. M3AlN ceramics are predicted to be “quasi-ductile” layered nitrides based on the low shear-modulus-to-bulk-modulus ratios, positive Cauchy pressure (c12–c44), and lower ideal shear strength compared to ideal tensile strength. Investigation of the atomistic shear deformation mechanism of Hf3AlN shows that stretching of soft Al–Hf bonds and relatively weak bridge N–Hf1 bonds dominate the shear deformation; while the rigid N–Hf2 bonds resist against the applied shear strain. Chemical bonding characteristics and shear deformation mechanism of M3AlN are similar with those of other “quasi-ductile” ceramics, such as MAX phases, LaPO4 monazite, and γ-Y2Si2O7. The results further suggest that M3AlN nitrides should be quasi-ductile and damage tolerant.
Near-threshold fatigue crack growth in bulk metallic glass composites
Authors: Boopathy Kombaiah , Hofmann Douglas C. , Johnson William L. , Ramamurty Upadrasta
Published: November 2009

A major drawback in using bulk metallic glasses (BMGs) as structural materials is their extremely poor fatigue performance. One way to alleviate this problem is through the composite route, in which second phases are introduced into the glass to arrest crack growth. In this paper, the fatigue crack growth behavior of in situ reinforced BMGs with crystalline dendrites, which are tailored to impart significant ductility and toughness to the BMG, was investigated. Three composites, all with equal volume fraction of dendrite phases, were examined to assess the influence of chemical composition on the near-threshold fatigue crack growth characteristics. While the ductility is enhanced at the cost of yield strength vis-à-vis that of the fully amorphous BMG, the threshold stress intensity factor range for fatigue crack initiation in composites was found to be enhanced by more than 100%. Crack blunting and trapping by the dendritic phases and constraining of the shear bands within the interdendritic regions are the micromechanisms responsible for this enhanced fatigue crack growth resistance.
Anisotropic design of a multilayered biological exoskeleton
Authors: Wang Lifeng , Song Juha , Ortiz Christine , Boyce Mary C.
Published: November 2009

Biological materials have developed hierarchical and heterogeneous material microstructures and nanostructures to provide protection against environmental threats that, in turn, provide bioinspired clues to improve human body armor. In this study, we present a multiscale experimental and computational approach to investigate the anisotropic design principles of a ganoid scale of an ancient fish,Polypterus senegalus,which possesses a unique quad-layered structure at the micrometer scale with nanostructured material constituting each layer. The anisotropy of the outermost prismatic ganoine layer was investigated using instrumented nanoindentations and finite element analysis (FEA) simulations. Nanomechanical modeling was carried out to reveal the elastic-plastic mechanical anisotropy of the ganoine composite due to its unique nanostructure. Simulation results for nanoindentation representing ganoine alternatively with isotropic, anisotropic, and discrete material properties are compared to understand the apparent direction-independence of the anisotropic ganoine during indentation. By incorporating the estimated anisotropic mechanical properties of ganoine, microindentation on a quad-layered FEA model that is analogous to penetration biting events (potential threat) was performed and compared with the quad-layered FEA model with isotropic ganoine. The elastic-plastic anisotropy of the outmost ganoine layer enhances the load-dependent penetration resistance of the multilayered armor compared with the isotropic ganoine layer by (i) retaining the effective indentation modulus and hardness properties, (ii) enhancing the transmission of stress and dissipation to the underlying dentin layer, (iii) lowering the ganoine/dentin interfacial stresses and hence reducing any propensity toward delamination, (iv) retaining the suppression of catastrophic radial surface cracking, and favoring localized circumferential cracking, and (v) providing discrete structural pathways (interprism) for circumferential cracks to propagate normal to the surface for easy arrest by the underlying dentin layer and hence containing damage locally. These results indicate the potential to use anisotropy of the individual layers as a means for design optimization of hierarchically structured material systems for dissipative armor.
The characterization of corrosion resistance in the Ti-6Al-4V alloy fusion zone using a gas tungsten arc welding process
Authors: Wang L.M. , Lin H.C.
Published: November 2009

The Ti-6Al-4V sheet alloys were welded by using a common gas tungsten arc welding process. In this work, we study the correlation of corrosion resistance and oxide layer structure produced after commonly used industrial heat treatments. We also study the oxide scales that were formed as a result of the heat-related treatment/aging process. The results indicate that better corrosion resistance of the Ti-6Al-4V alloy weldment can be obtained and significantly improved by a solution treatment plus an artificial aging (ST+AA) treatment, owing to the enhanced intensity of TiO2, V2O5, and Al2O3 oxides that compacted and grew on the surface of fusion zone. The newly found γ-TiAl and α2-Ti3Al particles that nucleated in the fusion zone due to different heat treatments do affect the composition of the oxide layer. The possible mechanism for this oxide layer formation in the fusion zone is discussed.
The origin of nuclei and the refinement mechanism for solidified superalloy IN718 under pulsed magnetic field
Authors: Ma Xiaoping , Li Yingju , Yang Yuansheng
Published: November 2009

The grain refinement effect of a pulsed magnetic field on superalloy IN718 was investigated. The experimental results show that fine equiaxed grains are acquired under the pulsed magnetic field. The refinement effect of the pulsed magnetic field is affected by the mold temperature. And the mixed grains are found in the solidified microstructures under the pulsed magnetic field. The origin of nuclei under the pulsed magnetic field is from the mold wall because of the rough mold surface, the undercooling, and the melt vibration, which all contribute to the refinement of solidified grains.
Defects in three-dimensional spherical assemblies of Ni-doped ZnO nanocrystals
Authors: Barick K.C. , Aslam M. , Wu Jinsong , Dravid Vinayak P. , Bahadur D.
Published: November 2009

Three-dimensional spherical assemblies of Ni-doped ZnO nanocrystals have been prepared by the solution phase synthesis process. It has been observed that transition metal ions (Zn, Ni) are uniformly distributed in the sample and exist in the +2 oxidation state. Detailed investigation of structural defects formed during the formation of spherical assemblies by oriented attachment of nanocrystals was carried out by high-resolution transmission electron microscope (HRTEM), Raman and photoluminescence (PL) spectroscopy. HRTEM analysis revealed the existence of various crystal defects, such as stacking faults, dislocations, etc. The incorporation of Ni2+ into ZnO structure strongly influences the vibrational and optical properties of the sample due to the increment of defect densities. Compared to the optical phonons of ZnO, additional mode observed at 538 cm−1 in Raman spectra of Ni-doped ZnO could be associated with the incorporation of Ni2+ in Zn2+ site. The increase in PL intensity of green emission with Ni2+ doping indicates the formation of a higher concentration of oxygen vacancy in doped nanostructures.
In situ observations on deformation behavior and stretching-induced failure of fine pitch stretchable interconnect
Authors: Hsu Yung-Yu , Gonzalez Mario , Bossuyt Frederick , Axisa Fabrice , Vanfleteren Jan , Wolf Ingrid De
Published: November 2009

Electronic devices capable of performing in extreme mechanical conditions such as stretching, bending, or twisting will improve biomedical and wearable systems. The required capabilities cannot be achieved with conventional building geometries, because of structural rigidity and lack of mechanical stretchability. In this article, a zigzag-patterned structure representing a stretchable interconnect is presented as a promising type of building block. In situ experimental observations on the deformed interconnect are correlated with numerical analysis, providing an understanding of the deformation and failure mechanisms. The experimental results demonstrate that the zigzag-patterned interconnect enables stretchability up to 60% without rupture. This stretchability is accommodated by in-plane rotation of arms and out-of-plane deformation of crests. Numerical analysis shows that the dominating failure cause is interfacial in-plane shear stress. The plastic strain concentration at the arms close to the crests, obtained by numerical simulation, agrees well with the failure location observed in the experiment.