bluuebunny/crossref_metadata_2025 huggingface dataset:
Hardness Testing
Authors: Edwards Janice
Published: May 2012

Indentation hardness tests such as Brinell, Rockwell, Vickers, Knoop, and instrumented indentation are frequently used methods for determining hardness. The basic concept utilized in all of these tests is that a set force is applied to an indenter in order to determine the resistance of the material to penetration. If the material is hard, a relatively small or shallow indentation will result, whereas if the material is soft, a fairly large or deep indentation will result.

These tests are often classified in one of the following two ways: by the extent of the test force applied or the measurement method used. A “macro” test refers to a test where a load >1 kg is applied; similarly “micro” refers to a test where a load of ≤1 kg of force is applied. Additionally, some instruments are capable of conducting tests with loads as light as 0.01 g and are commonly referred to as ultralight or nanoindentation testers. Rockwell and Brinell testers fall into the macro category, whereas Knoop testers are used for microindentation tests. Vickers and instrumented indentation testers can be employed for both macro‐ and microindentation tests. The measurement methods available include a visual observation of the indentation or a depth measurement of the indentation. Rockwell and instrumented indentation testers are capable of determining the depth of the indentation, whereas Brinell, Knoop, and Vickers testers require an indentation diameter measurement. These visual measurements can be automated, as will be discussed later in this article.

Hardness is not a fundamental property of a material, yet hardness testing is considered a useful quality‐control tool. Many properties are predicted from hardness values when combined with additional information such as alloy composition. The following is a list of such properties: resistance to abrasives or wear, resistance to plastic deformation, modulus of elasticity, yield strength, ductility, and fracture toughness. Some of these properties, such as yield strength, have numerical relationships with hardness values, whereas others such as fracture toughness are based on observations of cracks surrounding the indentations. Data analysis and conversions will be discussed in greater detail later in this article.
Tribological and Wear Testing
Authors: Bayer Raymond G.
Published: May 2012

Tribology is the science of friction, wear, and lubrication. More fundamentally, tribology is concerned with the interaction of contacting surfaces in relative motion. Friction is the resisting tangential force that occurs between two surfaces in contact when they move or tend to move relative to one another. For solid surfaces the magnitude of this force is characterized by the coefficient of friction, defined as the dimensionless ratio of the magnitude of the friction force to the magnitude of the normal force. In the absence of an externally applied normal force, this tangential force is sometimes referred to as sticktion. Wear is damage to a solid surface due to the relative motion between that surface and a contacting substance or substances. It involves the progressive loss of material. Lubrication is the ability of an interposing material to reduce either the friction between or the wear of surfaces.

The tribological behavior that a material exhibits is dependent on both the properties of the material and the contact conditions. As a result, parameters used to characterize the friction, wear, and lubrication of a material are system properties of the material, not intrinsic properties such as an elastic modulus or coefficient of thermal expansion. The collection of all those elements that can influence tribological behavior is referred to as the tribosystem. The primary elements of a tribosystem are (1) materials, (2) shapes and contours, (3) surface roughness, (4) motions, (5) loading, (6) lubrication, and (7) environment.
Theory of Magnetic Phase Transitions
Authors: McHenry Michael E. , Laughlin David E.
Published: May 2012

This article discusses magnetic order and a class of physical phenomena that can be described as magnetic phase transitions. We describe the thermodynamics of magnetic ordering transitions, the order of the transitions, critical exponents, and thermodynamic variables. We further describe magnetic phase transitions within the framework of the mean field Landau theory of phase transitions with discussion of several magnetic equations of state. We end with an application to magnetocaloric materials.
Techniques to Measure Magnetic Domain Structures
Authors: Celotta R. J. , Unguris J. , Kelley M. H. , Pierce D. T.
Published: May 2012

Critical to understanding the magnetic properties and the technological application of magnetic materials is the ability to observe and measure magnetic domain structure. The measurement challenge is quite varied. Magnetic fluids can be used to decorate and make simple domain structures visible while highly sophisticated electron microscopy‐based methods may be needed to explore and image nanometer‐scale magnetic phenomena. No one method will solve all of the domain imaging problems. For that reason, the bases of the important methods and the practical implications of each are discussed.

For purposes of comparison, several important characteristics of each domain imaging technique are briefly summarized.

There are several general comments that apply to every domain imaging method discussed in this article. First, each method is related either to a sample's magnetization or to the magnetic field generated by that magnetization. The former observation is of great usefulness in understanding or developing new materials, and the latter is of practical importance in devices. Second, all of the methods are limited to the topmost few micrometers of the sample, and are therefore dominated by magnetic structure related to the surface. None provide the domain structure of the interior of a thick sample where bulk magnetic microstructure is fully developed. Third, all of the methods require smooth, clean, damage‐free surfaces. In general, the surfaces need to have at least the equivalent of a mirror polish, otherwise, topography and surface stress will affect the measurement to varying degrees. Fourth, correlations exist between several of the parameters in each technique we describe. For example, it may not be possible to achieve the ultimate sensitivity specified at the highest resolution possible. Finally, almost all of the techniques use digital signal acquisition and can benefit from the use of modern image processing tools.

Expanded discussions of the basis of each technique, its practical aspects, sample preparation required, possible sample modifications, and problems that are specific to the technique described are given. Each section contains references to more complete treatments of the technique and recent examples of its use.
The Quartz Crystal Microbalance in Electrochemistry
Authors: Arbuckle‐Keil Georgia A.
Published: May 2012

The quartz crystal microbalance (QCM) is based on the principle that a change in resonance frequency of a quartz crystal is directly proportional to a change in total mass (crystal and surface deposit). When one of the quartz crystal contacts is the working electrode of an electrochemical cell, the charge passed during an electrochemical process can be correlated with nanogram mass changes on the quartz crystal electrode. Other factors that influence overall frequency change include viscoelastic behavior of electrode deposit, surface roughness, entrapment of solvent or air in electrode deposit, nonuniform mass distribution, and ambient temperature changes. The ability to determine both the energy dissipation,
D
, and resonance frequency change,
f
r
, illustrates the use of QCM as both a gravimetric and viscoelastic probe of materials deposited onto the quartz crystal electrode surface.
Photoluminescence Spectroscopy
Authors: Aoki Takeshi
Published: May 2012

This article presents a brief introduction to photoluminescence (PL) spectroscopy in solid‐state physics and technology, known as fluorescence spectroscopy in chemistry and biology. Though PL spectroscopy is usually known as spectral‐resolved spectroscopy, time‐resolved PL spectroscopy containing information about recombination lifetime of photoexcited electrons and holes has now become essential to the PL study on various materials ranging from nanoparticles to living tissues. Since a variety of methods of PL spectroscopy exist, they are classified into three categories, namely, static or steady‐state PL spectroscopy, time‐resolved PL spectroscopy, and frequency‐resolved spectroscopy, each of which groups several methods, and, moreover, PL mapping and imaging are also addressed in the text.
Ultraviolet and Visible Absorption Spectroscopy
Authors: Tissue Brian M.
Published: May 2012

This article describes the principles and applications of absorption spectroscopy in the ultraviolet (UV), visible (Vis), and near‐infrared (NIR) regions of the electromagnetic spectrum. UV/Vis spectroscopy is used for (1) quantitative measurements of material components and precursors and (2) characterization of the optical and electronic properties of a material. Most measurements can be made with commercially available spectrophotometers and sampling accessories.
Nuclear Magnetic Resonance Imaging
Authors: Hornak Joseph P.
Published: May 2012

Nuclear magnetic resonance imaging (MRI) is a common imaging modality in clinical settings because of its excellent ability to discriminate between different soft tissues or matter. For this same reason, MRI is a useful analytical tool for characterizing materials. This article covers the theory and capabilities of MRI as applied to the studies of materials.
Cyclotron Resonance
Authors: Hilton, D. J. , Arikawa, T. , Kono J.
Published: May 2012

This article reviews the technique and phenomenon of cyclotron resonance (CR). CR is a method for measuring the effective masses of charge carriers in solids and is by far the most direct and accurate method for providing such information. In the 1950s, the first CR studies were carried out in germanium and silicon crystals, which, in conjunction with the effective mass theory, successfully determined the band‐edge parameters for these materials with unprecedented accuracy. Since then, CR has been investigated in a large number of elementary and compound materials and their alloys and heterostructures. Quantum mechanically, CR can be viewed as a transition between adjacent Landau levels. In real solids, Landau levels are generally not equally spaced since the energy dispersion relation is not generally given by a simple parabolic dispersion relation, and, thus, effective masses are energy dependent as well as direction dependent. A detailed comparison between theory and experiment on quantum CR can provide a critical test of the band theory of solids. As a secondary purpose, one can also use CR to study carrier scattering phenomena in solids by examining the scattering. As the frequency of scattering events increases, CR linewidth increases, and, eventually, CR becomes unobservable when scattering occurs too frequently. Temperature and magnetic field dependence of CR linewidth provides insight into dominant scattering mechanisms.
Mössbauer Spectrometry
Authors: Fultz Brent
Published: May 2012

Mössbauer spectrometry provides unique measurements of electronic, magnetic, and structural properties within materials. A Mössbauer spectrum is an intensity of γ‐ray absorption versus energy for a specific resonant nucleus such asor. Mössbauer spectrometry looks at materials from the “inside out,” where “inside” refers to the resonant nucleus. For one nucleus to emit a γ ray and a second nucleus to absorb it with efficiency, both nuclei must be embedded in solids, a phenomenon known as the “Mössbauer effect.”

Mössbauer spectra give quantitative information on “hyperfine interactions,” which are small energies from the interaction between the nucleus and its neighboring electrons. The three important hyperfine interactions originate from the electron density at the nucleus (the isomer shift), the gradient of the electric field (the nuclear quadrupole splitting), and the unpaired electron density at the nucleus (the hyperfine magnetic field). Over the years, methods have been refined for using these three hyperfine interactions to determine valence and spin at the resonant atom. Even when the hyperfine interactions are not easily interpreted, they can often be used reliably as “fingerprints” to identify the different local chemical environments of the resonant atom, usually with a good estimate of their fractional abundances. Mössbauer spectrometry is useful for quantitative phase analyses or determinations of the concentrations of resonant element in different phases, even when the phases are nanostructured or amorphous.

Most Mössbauer spectra are acquired with simple laboratory equipment and a radioisotope source, but the recent development of synchrotron instrumentation now allows for measurements on small 10‐μm samples, which may be exposed to extreme environments of pressure and temperature. Other capabilities include measurements of the vibrational spectra of resonant atoms, and coherent scattering and diffraction of nuclear radiation.

This article is not a review of the field, but an instructional reference that explains principles and practices, and gives the working materials scientist a basis for evaluating whether or not Mössbauer spectrometry may be useful for a research problem. A few representative materials studies are presented.
XAFSSpectroscopy
Authors: Heald Steve
Published: May 2012

The x‐ray absorption fine structure (XAFS) that is present near x‐ray absorption edges contains detailed information about the local structure and bonding of the absorbing atoms. With the advent of intense tunable sources of x‐rays using synchrotron radiation facilities, the application of x‐ray absorption spectroscopy has become widespread and routine. The XAFS is a local probe sensitive to the location and type of atoms surrounding the absorbing atom. As a local probe, it can be applied to many materials where diffraction‐based techniques would be impractical such as resolving the structure near highly dilute components and determining the local structure of atoms in nanoparticles, liquids, metalloproteins in solution, amorphous solids, and poorly crystalline materials. In addition to the direct structural information, the absorption edge position and shape can be used to determine the site symmetry and valence of the absorbing atoms. This chapter describes the physical principles that result in the fine structure, basic experimental techniques, and basic principles for the extraction of the information present in the spectra. It also touches on some of the unique aspects of performing measurements at a synchrotron radiation facility.
Scanning Tunneling Microscopy
Authors: Park Jeong Y.
Published: May 2012

Scanning tunneling microscopy (STM) is an instrument in which a sharp metallic probe raster scanned across the sample is employed to detect changes in surface structure on the atomic scale. STM enabled us to study surface structure, electronic structure, atomic manipulation, dynamics of molecules and atoms, and chemical properties of the surface at the atomic scale. During the last three decades, the field of scanning tunneling microscopy has advanced explosively. New experimental modes and theoretical models have been developed. In this chapter, the principle and practical aspects of the new methods associated with STM techniques are outlined. Variation of STM and scanning tunneling spectroscopy (STS) and their principles and examples are also shown here. Data analysis, sample preparations, and problems of various STM experiments are introduced as well.
Magnetic Neutron Scattering
Authors: Lynn Jeffrey W.
Published: May 2012

Neutron scattering is a powerful tool to investigate the magnetic structures and spin dynamics of materials. In this tutorial we provide examples of the application of magnetic neutron diffraction using polycrystalline materials, single crystals, thin films, and artificially grown multilayers, to determine the spatial arrangement and directions of the atomic magnetic moments, the atomic magnetization density of magnetic ions, and the ordered moments as a function of thermodynamic variables such as temperature, pressure, and applied magnetic field. We also present examples of the technique of inelastic scattering to determine the spin dynamics of systems. Both polarized and unpolarized neutron techniques are discussed.
Effect of Temperature on the Dynamic Mechanical Behaviors of Zr‐Based Metallic Glass Reinforced Porous Tungsten Matrix Composite
Authors: Chen Chen , Xue Yunfei , Wang Lu , Cheng Xingwang , Wang Fuchi , Wang Zhengbin , Zhang Haifeng , Wang Aiming
Published: May 2012

The dynamic mechanical behaviors of Zr‐based metallic glass reinforced porous tungsten matrix composite were investigated by a split Hopkinson pressure bar at different testing temperatures. The flow stress of the composite decreased, while the ductility increased with increasing testing temperature, which were attributed to that more microcracks were initiated in the tungsten phase as well as more microshear bands were induced in the metallic glass phase with increasing temperature. The failure mode of the composite is a mixture of shearing and axial splitting. The flow layer of the metallic glass phase in the shearing fracture surface at 473 K was longer and thinner than that at 223 K.
Epitaxial NiMnGa Films for Magnetic Shape Memory Alloy Microactuators
Authors: Backen Anja , Yeduru Srinivasa Reddy , Diestel Anett , Schultz Ludwig , Kohl Manfred , Fähler Sebastian
Published: May 2012

Active materials such as piezoelectrics are established in the field of microsystems application despite their low achievable strains which often require the integration of additional gear mechanisms. The ongoing search for new active materials has focused on magnetic shape memory (MSM) alloys such as NiMnGa since they combine macroscopic strains of up to 10% with a cycling frequency well above the frequencies of conventional thermal shape memory alloys. The present review focuses on preparation and analysis of NiMnGa films that can eventually be integrated in microsystems. Single crystal like films are prepared by epitaxial growth on suitable substrate materials. Since the magnetically induced reorientation of variants is blocked by a rigid substrate, we present different methods for releasing films from the substrates. We show that the sacrificial layer technology is the most promising approach. Further processing of the freestanding film requires a microtechnology which is adjusted to the film laminate structure. The properties of the freestanding films are compared with films on a rigid substrate. Although we observe stress‐induced twin boundary motion, the twinning stress is too high to be overcome by an external magnetic field. Therefore, it is necessary to develop suitable training methods to reduce the twinning stress below 2 MPa to enable the activation of the material by means of an external magnetic field.
Principle Design of Actuators Driven by Magnetic Shape Memory Alloys
Authors: Schlüter Kathrin , Holz Benedikt , Raatz Annika
Published: May 2012

Magnetic shape memory alloys (MSMA) are a promising material for actuation purposes as they provide relatively large strains and relatively high operation frequencies. In this paper three concepts of such actuators are introduced. The first part will describe a so called spring actuator, where the MSM element is working against a restore pre‐stress spring. The second concept uses two MSM elements working antagonistically to substitute the pre‐stress spring. A small sized actuator for valve or switching applications is shown in the third concept. Advantages and disadvantages are highlighted and show the potential of the comparatively new active material.
Revisited Storage and Dynamic Recovery of Dislocation Density Evolution Law: Toward a Generalized Kocks–Mecking Model of Strain‐Hardening
Authors: Bouaziz O.
Published: May 2012

The current work extends the well established approach of Kocks and Mecking by a more realistic description of strain‐hardening using an original dislocation density law with a revisited physical understanding of dynamic recovery, without new material parameters and keeping only one internal variable.
Efficient Synthesis of Heteroatom (N or S)‐Doped Graphene Based on Ultrathin Graphene Oxide‐Porous Silica Sheets for Oxygen Reduction Reactions
Authors: Yang Shubin , Zhi Linjie , Tang Kun , Feng Xinliang , Maier Joachim , Müllen Klaus
Published: May 2012

Heteroatom (N or S)‐doped graphene with high surface area is successfully synthesized via thermal reaction between graphene oxide and guest gases (NH3 or H2S) on the basis of ultrathin graphene oxide‐porous silica sheets at high temperatures. It is found that both N and S‐doping can occur at annealing temperatures from 500 to 1000 °C to form the different binding configurations at the edges or on the planes of the graphene, such as pyridinic‐N, pyrrolic‐N, and graphitic‐N for N‐doped graphene, thiophene‐like S, and oxidized S for S‐doped graphene. Moreover, the resulting N and S‐doped graphene sheets exhibit good electrocatalytic activity, long durability, and high selectivity when they are employed as metal‐free catalysts for oxygen reduction reactions. This approach may provide an efficient platform for the synthesis of a series of heteroatom‐doped graphenes for different applications.
Nano‐ and Mesoscale Structure of Na$_{1 \over 2}$Bi$_{1 \over 2}$TiO3: A TEM Perspective
Authors: Levin Igor , Reaney Ian M.
Published: May 2012

The room‐temperature structure of Na$_{1 \over 2}$Bi$_{1 \over 2}$TiO3 (NBT) ceramics was studied using several transmission electron microscopy (TEM) techniques. High‐angle annular dark field imaging in a scanning TEM confirmed an essentially random distribution of Bi and Na, while electron diffraction revealed significant disorder of the octahedral rotations and cation displacements. Diffraction‐contrast dark‐field and Fourier‐filtered high‐resolution TEM images were used to develop a model that reconciles local and average octahedral tilting in NBT. According to this model, NBT consists of nanoscale twin domains which exhibit a−a−c+ tilting. The coherence length of the in‐phase tilting, however, is limited to a few unit cells and is at least one order of magnitude shorter than that of anti‐phase tilting. Assemblages of such nanodomains are proposed to exhibit an average a−a−c− tilt system. Diffuse sheets of intensity in electron diffraction patterns are attributed to local cation displacements correlated along both 〈111〉 and 〈100〉 chains and suggest partial polar ordering of these displacements. Overall, the TEM data indicate significant chemical, cation‐displacement and tilt disorder of the NBT structure at the nano and mesoscale and support the premise that the Cc symmetry recently proposed from powder diffraction refinements is an averaged “best fit” cell.
A New View of Microcrystalline Silicon: The Role of Plasma Processing in Achieving a Dense and Stable Absorber Material for Photovoltaic Applications
Authors: Bugnon Grégory , Parascandolo Gaetano , Söderström Thomas , Cuony Peter , Despeisse Matthieu , Hänni Simon , Holovský Jakub , Meillaud Fanny , Ballif Christophe
Published: May 2012

To further lower production costs and increase conversion efficiency of thin‐film silicon solar modules, challenges are the deposition of high‐quality microcrystalline silicon (μc‐Si:H) at an increased rate and on textured substrates that guarantee efficient light trapping. A qualitative model that explains how plasma processes act on the properties of μc‐Si:H and on the related solar cell performance is presented, evidencing the growth of two different material phases. The first phase, which gives signature for bulk defect density, can be obtained at high quality over a wide range of plasma process parameters and dominates cell performance on flat substrates. The second phase, which consists of nanoporous 2D regions, typically appears when the material is grown on substrates with inappropriate roughness, and alters or even dominates the electrical performance of the device. The formation of this second material phase is shown to be highly sensitive to deposition conditions and substrate geometry, especially at high deposition rates. This porous material phase is more prone to the incorporation of contaminants present in the plasma during film deposition and is reported to lead to solar cells with instabilities with respect to humidity exposure and post‐deposition oxidation. It is demonstrated how defective zones influence can be mitigated by the choice of suitable plasma processes and silicon sub‐oxide doped layers, for reaching high efficiency stable thin film silicon solar cells.
Microwave‐Assisted Surface Synthesis of a Boron–Carbon–Nitrogen Foam and its Desorption Enthalpy
Authors: Paul Rajib , Voevodin Andrey A. , Zemlyanov Dimitry , Roy Ajit K. , Fisher Timothy S.
Published: May 2012

The modification of microporous carbon foam with boron and nitrogen through a facile microwave chemical treatment are reported. The resulting surfaces of the foam exhibit distinct B–N and carbon domains based on chemical and microscopic analysis, in keeping with theoretical predictions. The resultant materials are shown to exhibit exceptionally high methanol desorption enthalpy and thermal stability in comparison to untreated carbon foam and consequently are suggested as candidate materials for sorption cooling and thermal storage applications using methanol as the adsorbate.
Chemical and Topographical Effects on Cell Differentiation and Matrix Elasticity in a Corneal Stromal Layer Model
Authors: Wilson Samantha L. , Wimpenny Ian , Ahearne Mark , Rauz Saaeha , El Haj Alicia J. , Yang Ying
Published: May 2012

Control and maintenance of the keratocyte phenotype is vital to developing in vitro tissue engineered strategies for corneal repair. In this study the influence of topographical and chemical cues on the mechanical, phenotypical and genotypical behaviour of adult human derived corneal stromal (AHDCS) cells in three dimensional (3D) multi‐layered organised constructs is examined. Topographical cues are provided via multiple aligned electrospun nanofiber meshes, which are arranged orthogonally throughout the constructs and are capable of aligning individual cells and permitting cell migration between the layers. The influence of chemical cues is examined using different supplements in culture media. A non‐destructive indentation technique and optical coherence tomography are used to determine the matrix elasiticity (elastic modulus) and dimensional changes, respectively. These measurements were indicative of changes in cell phenotype from contractile fibroblasts to quiescent keratocytes over the duration of the experiment and corroborated by qPCR. Constructs containing nanofibers have a higher initial modulus, reduced contraction and organised cell orientation compared to those without nanofibers. Cell‐seeded constructs cultured in serum‐containing media increased in modulus throughout the culture period and underwent significantly more contraction than constructs cultured in serum‐free and insulin‐containing media. This implies that the growth factors present in serum promote a fibroblast‐like phenotype; qPCR data further validates these observations. These results indicate that the synergistic effect of nanofibers and serum‐free media plus insulin supplementation provide the most suitable topographical and chemical environment for reverting corneal fibroblasts to a keratocyte phenotype in a 3D construct.
Lateral Buckling of High Aspect Ratio Janus Nanowalls
Authors: Yoon Hyunsik , Ghosh Abhijit , Han Jung Yeon , Sung Seung Hyun , Lee Won Bo , Char Kookheon
Published: May 2012

In recent years, the fabrication of Janus materials and their potential applications has been of much interest in Materials Science. Here, we report the fabrication of an entirely novel structure–Janus nanowalls and the phenomenon of lateral buckling in them. Polymeric nanowalls were prepared with the replica molding technique and metal films, of comparable thicknesses, were then deposited on one side of the polymer nanowalls by vacuum process. During the metal deposition, the nanowalls themselves buckle laterally; this buckling is induced by the compressive residual stress in the metal film and geometric confining constraints. The feature of wrinkle patterns resulting from the lateral buckling was theoretically investigated using the scaling analysis. Theoretical results are in good agreement with the experimental observations.
Inorganic Nanoparticles Based Contrast Agents for X‐ray Computed Tomography
Authors: Jakhmola Anshuman , Anton Nicolas , Vandamme Thierry F.
Published: May 2012

Nanomaterials have gained considerable attention and interest in the development of new and efficient molecular probes for medical diagnosis and imaging. Heavy metal nanoparticles as such are excellent absorber of X‐rays and can offer excellent improvement in medical diagnosis and X‐ray imaging. Substantial progress has been made in the synthesis protocol and characterization studies of these materials but a major challenge still lies in the toxicological studies, which are rather incomplete. The worst known cases were those associated with Thorotrast (suspension of ThO2 nanoparticles) which resulted in many deaths over years. Properly protected nanomaterials conjugated or coated with biocompatible materials can be used for the fabrication of various functional systems with multimodality, targeting properties, reduced toxicity and proper removal from the body. This review aims mainly to provide the advances in the development of inorganic nanoparticle based X‐ray contrasting agents with an overview of methods of their preparation, functionalization and applications in medical diagnosis.
Elastic and Piezoelectric Properties of Zincblende and Wurtzite Crystalline Nanowire Heterostructures
Authors: Boxberg Fredrik , Søndergaard Niels , Xu H. Q.
Published: May 2012

The elastic and piezoelectric properties of zincblende and wurtzite crystalline InAs/InP nanowire heterostructures have been studied using electro‐elastically coupled continuum elasticity theory. A comprehensive comparison of strains, piezoelectric potentials and piezoelectric fields in the two crystal types of nanowire heterostructures is presented. For each crystal type, three different forms of heterostructures—core‐shell, axial superlattice, and quantum dot nanowire heterostructures—are considered. In the studied nanowire heterostructures, the principal strains are found to be insensitive to the change in the crystal structure. However, the shear strains in the zincblende and wurtzite nanowire heterostructures can be very different. All the studied nanowire heterostructures are found to exhibit a piezoelectric field along the nanowire axis. The piezoelectric field is in general much stronger in a wurtzite nanowire heterostructure than in its corresponding zincblende heterostructure. Our results are expected to be particularly important for analyzing and understanding the properties of epitaxially grown nanowire heterostructures and for applications in nanowire electronics, optoelectronics, and biochemical sensing.
Process monitoring using principal components in parallel coordinates
Authors: Dunia Ricardo , Edgar Thomas F. , Nixon Mark
Published: May 2012

Parallel coordinates is a recognized visualization technique in which data points, each defined by multiple coordinates, are represented by an unlimited number of adjoining parallel axes. This type of visualization technique is suitable for process monitoring applications in industrial facilities where a significant number of sensors are used to detect and identify abnormal operating conditions. This work makes use of principal component monitoring methods implemented in parallel coordinates plots, named PC2. The PC2 capabilities to visualize confidence regions of operations, evaluate models with different number of principal components, compare faulty events and determine the frequency of false alarms are here demonstrated. The monitoring visualization technology presented by PC2 was successfully used for early detection of compressor surge and column flooding using actual process data. © 2012 American Institute of Chemical Engineers AIChE J, 59: 445–456, 2013
(MnzFe1—z)yOx combined oxides as oxygen carrier for chemical‐looping with oxygen uncoupling
Authors: Azimi Golnar , Rydén Magnus , Leion Henrik , Mattisson Tobias , Lyngfelt Anders
Published: May 2012

Oxygen carrier particles with the composition (Mn0.8,Fe0.2)2O3 were found to readily release gas phase oxygen at 850°C, and were capable to oxidize CH4 completely and convert wood char rapidly to CO2 during experiments in a batch fluidized bed reactor. The particles were able to release oxygen corresponding to more than 3% of their mass in less than 40 s. Because of the low price and favourable environmental properties of manganese and iron oxides, this finding could be of great importance for the development of chemical‐looping combustion with oxygen uncoupling. © 2012 American Institute of Chemical Engineers AIChE J, 59: 582–588, 2013
Simulation and application of response surface methodology to a nylon‐6 hydrolytic polymerization in a semibatch reactor
Authors: Funai Vanessa Ito , Melo Delba Nisi Cosme , Lima Nádson Murilo Nascimento , Filho Rubens Maciel
Published: May 2012

This work presents an experimental design methodology combined with computational simulation to correlate the influence of operational conditions and reactants charge in the numeric average molecular weight (MWN) as well as on monomer conversion (XCL), for the hydrolytic polymerization of nylon‐6 in a semibatch reactor. It evaluated the reaction temperature, the pressure profile, and the proportion of reactants in the charge. Experimental design was used to screen the most statistically significant variables and to develop a reliable predictive model for each response. The combined use of the models can be applied for process optimization, by establishing MWN and maximum XCL as objective functions. Responses surface allowed the visualization of the responses behavior when changing the independent variables and therefore to identify the optimal tendencies. This work demonstrates that such methodology can be applied for optimization of complex processes like the hydrolytic polymerization of nylon‐6. This polymerization has many side reactions occurring at the same time, which are sensitive to different profiles of pressure and temperature that are applied. This evaluation is quite interesting as such profiles are necessary to perform the several polymerization steps and have a significant impact on product characteristics and therefore in its applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Edible starch sodium octenyl succinate film formation and its physical properties
Authors: Liu Zhaoli , Liu Xiudong , Cao Yafeng , Xie Weiyang , Ma Xiaojun , Yu Xingju
Published: May 2012

Edible starch sodium octenyl succinate (SSOS) films, with or without glycerol as plasticizer, were prepared by solution‐casting method. The effect of SSOS concentration, degree of substitution (DS) of octenyl group, as well as glycerol content, on the properties of SSOS films was studied including tensile strength, water vapor permeability (WVP), and oil permeability (OP). The results indicated that the tensile strength of SSOS film was up to 39.4 ± 1.9 MPa when the concentration of SSOS was 0.05 g/mL and DS was 0.05. The increase of glycerol content resulted in a decrease of film tensile strength. WVP of SSOS films was relatively low. Meanwhile, study in OP showed that SSOS films were oilproof. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Toughening of unmodified polyvinylchloride through the addition of nanoparticulate calcium carbonate and titanate coupling agent
Authors: Kemal I. , Whittle A. , Burford R. , Vodenitcharova T. , Hoffman M.
Published: May 2012

PVC/CaCO3 polymer nanocomposites of differing compositions were produced using a two‐roll mill and compression molding. In all formulations, 0.6 phr of titanate was incorporated to assist dispersion during processing. The morphology was observed using transmission electron microscopy, and the static and dynamic mechanical and fracture properties were determined. Fracture toughness examination was performed according to strain energy release test method. The presence of nanometer‐sized CaCO3 particles led to a slight decrease in the tensile strength but improved the impact energy absorption, storage modulus, and fracture toughness. The use of titanate coupling agent softened the polymer matrix and reduced the matrix's modulus. Fracture surface examinations by scanning electron microscopy showed that the coupling agent improved particle–matrix bonding and inhibited void formation around the particles. Finite element analysis suggested that the improved particle–matrix bonding reduced the matrix's plasticity around the particles, which decreased the toughening efficiency of the composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Viscosalines B1,2 and E1,2: Challenging New 3‐Alkyl Pyridinium Alkaloids from the Marine Sponge Haliclona viscosa
Authors: Schmidt Gesine , Timm Christoph , Grube Achim , Volk Christian A. , Köck Matthias
Published: May 2012

Four new 3‐alkyl pyridinium alkaloids, the viscosalines B1 (1 a), B2 (1 b), E1 (2 a), and E2 (2 b), were isolated from the Arctic sponge Haliclona viscosa. The structure elucidation of these isomeric compounds was challenging due to ambiguous fragments that derive during “standard” mass spectrometric fragmentation experiments. The final structure elucidation relied on the use of a combination of synthesis, liquid chromatography, and mass spectrometry. Three different mass spectrometers were used to differentiate between the synthetic structural isomers: a time‐of‐flight (TOF) mass spectrometer and two ion‐trap mass spectrometers with different ion‐transfer technologies (i.e., skimmer versus funnel optics). Although at first none of the spectrometers returned spectra that permitted structure elucidation, all three mass spectrometers provided analysis that successfully differentiated between the isomers after thorough method optimization. The use of in‐source collision‐induced dissociation (CID) with the ion trap and TOF instrument returned the most interesting results. The mode of fragmentation of the viscosalines under different experimental conditions is described herein. After successful optimization of the mass spectrometric method applied, the chromatographic method was improved to distinguish the previously inseparable isomers. Finally, both the liquid chromatography and mass spectrometric methods were applied to the natural products and the results compared to those from the synthetic compounds.
Surveillance of Invasive Bacterial Pathogens and Human Enteric Viruses in Wastewater Final Effluents and Receiving Water Bodies – a Case Study from Durban, South Africa
Authors: Olaniran Ademola O. , Naidoo Shalinee , Pillay Balakrishna
Published: May 2012

The physico‐chemical characteristics and microbial composition of the final effluents of two municipal wastewater treatment plants in South Africa were assessed between July and September 2009. The impact of the treated final effluents on the receiving water bodies was also evaluated. The temperature across all sampling points ranged between 14 and 22°C, while pH varied from 6.9 to 7.6. High levels of turbidity, chemical oxygen demand (COD), ammonia, nitrate, nitrite and orthophosphate (PO4) were observed in many cases. Turbidity of the samples was in the range of 2.2–288.6 NTU. The concentrations (mg/L) of other physico‐chemical parameters are as follows: COD (9.33–289); ammonia (0.000340–45.4); nitrate (0.062–539); nitrite (0.021–22.6); PO4 (5.3–33.2). The microbial quality of the effluents discharged from the plants did not comply with the limits set by the South African guidelines with respect to pathogens such as Salmonella, Shigella, Escherichia coli, total coliform, faecal coliform, enterococci, faecal streptococci, and viral particles for effluents intended for discharge into receiving watersheds. This study revealed an undesirable impact on the physico‐chemical and microbial qualities of the receiving water bodies as a result of the discharge of inadequately treated effluents from the wastewater treatment facilities. This poses a health risk to several rural communities which rely on the receiving water bodies primarily as their sources of domestic water and recreational purposes. There is therefore a need for the intervention of appropriate regulatory agencies in South Africa to ensure compliance of treatment facilities with wastewater effluent quality standards.
Growing Spirodela polyrrhiza in Swine Wastewater for the Production of Animal Feed and Fuel Ethanol: A Pilot Study
Authors: Xu Jiele , Cheng Jay J. , Stomp Anne‐M.
Published: May 2012

To evaluate the performance of Spirodela polyrrhiza grown in swine wastewater for protein and starch production under field conditions, a pilot‐scale duckweed culture pond was installed at Barham Farm, Zebulon, North Carolina and operated from May to November 2010. The anaerobically treated swine wastewater was fed to the duckweed pond intermittently to provide nutrients for the growth of duckweed, and the duckweed biomass was harvested regularly from the pond and prepared as a protein‐ or starch‐rich feedstock for the production of animal feed or fuel ethanol. Over the experimental period, the duckweed pond produced protein and starch at rates of 2.68 and 1.88 g m−2 day−1, respectively. During the same time, NH4–N and o‐PO4–P in the wastewater were, respectively, removed at rates of 92.9 and 2.90 mmol m−2 day−1.
Landfill Leachate Treatment: A Case Study for Istanbul City
Authors: Yaman Cevat , Ozcan Huseyin Kurtulus , Demir Goksel , Okten Hatice Eser , Yildiz Senol , Coban Asli , Balahorli Vahit
Published: May 2012

One of the most important problems arising from landfilling solid wastes is the leachate which contains high amount of pollution. Discharge of leachate without treatment causes negative effects on environmental and public health. In this study, parameters of chemical oxygen demand (COD), total nitrogen (TN), ammonia nitrogen (NH4‐N), and total phosphorus (TP) were examined in the samples taken from the influent and effluent of leachate treatment plant, where Odayeri landfill leachate is treated. Obtained results showed that the treatment plant, which consisted of preanoxic biological treatment system, ultrafiltration (UF) and nanofiltration (NF) units were operating with high efficiency. Among the examined parameters during study, COD, TN, NH4‐N, and TP were found to be treated at the rate of 99, 94.5, 99, and 93.8%, respectively. Landfilling is increasing rapidly in the world and this consequently brings the need of leachate treatment facilities. Therefore, this study is considered to be a guide for construction and operation stages of proposed new treatment plants.
Non‐thermal Effect of Atmospheric‐Pressure RF Cold Plasma on Photocatalytic Activity of As‐deposited TiO2 Film
Authors: Chang Da‐Lei , Li Xiao‐Song , Zhao Tian‐Liang , Yang Jin‐Hua , Zhu Ai‐Min
Published: May 2012

TiO2 film is deposited by atmospheric‐pressure (AP), radio‐frequency (RF), dielectric barrier discharge (DBD) plasma at a low power using titanium tetraisopropoxide (TTIP) and O2 as the precursors. The morphology, optical properties, and crystalline structure of the as‐deposited TiO2 film are investigated by using scanning electron microscopy (SEM), atomic force microscopy (AFM), ultraviolet‐visible (UV‐vis) absorption spectroscopy, and Raman spectroscopy. The as‐deposited TiO2 film show high photocatalytic activity in complete oxidation of HCHO to CO2 and degradation of stearic acid. The gas temperature in the RF‐DBD plasma is estimated to be at about 500 K by the rotational temperature via optical emission spectroscopy (OES). The experimental results of amorphous TiO2 film treated by the RF‐DBD plasma further exclude the likelihood of thermal effects derived from the plasma on crystallization of TiO2 film. It is confirmed that the non‐thermal effect of the RF‐DBD plasma on the high photocatalytic activity of the as‐deposited TiO2 film does exist.
The Multiple Ion Channel Blocker CPUY11018 Prevents Aconitine‐Induced Arrhythmias
Authors: Tang Yi‐Qun , Yu Peng , Zhao Na , Yang Qian , Yin Yue‐Miao , Le Xiao‐Yong , Guo Xiang , Wang Min‐Hui , Zhong Hao , You Qi‐Dong
Published: May 2012

Strategy, Management and Health Policy

Enabling Technology, Genomics, Proteomics
Preclinical Research
Preclinical Development Toxicology, Formulation Drug Delivery, Pharmacokinetics
Clinical Development Phases I‐III Regulatory, Quality, Manufacturing
Postmarketing Phase IV

In the present study, the potential antiarrhythmic activities of a new multiple ion channel blocker, CPUY11018 (Y18) were investigated. The effects of Y18 on ICa,L and INa were studied using whole‐cell patch clamp techniques in ventricular muscle cells from normal rats and guinea pigs. The antiarrhythmic effects were tested using a rat model of aconitine‐induced arrhythmias. The effects of Y18 on induction of QT prolongation and torsades de pointes (TdP) were investigated in anesthetized rabbits during stimulation with methoxamine. Y18 produced a concentration‐dependent inhibition of ICa,L and INa in rat ventricular myocytes with IC50 values of 88 μmol/l and 6.5 μmol/l, respectively. In the Y18 treatment group, the development of arrhythmias was significantly delayed. Doses of aconitine that induced ventricular fibrillation were decreased following treatment with 6 mg/kg Y18 (3.8 ± 0.4 μg/100 g vs 6.2 ± 1.3 μg/kg). A significant decrease in the occurrence of atrial fibrillation (100% to 33%; P < 0.05) occurred following Y18 administration. Y18 induction of TdP was significantly less than that seen with dofetilide and azimilide (Az). Thus, Y18 significantly inhibited the production of aconitine‐induced arrhythmias with a low potency for TdP induction. These results suggest that Y18 is a multiple channel blocker with promising antiarrhythmic potential.
The role of maternal stress during pregnancy, maternal discipline, and child COMT Val158Met genotype in the development of compliance
Authors: Kok Rianne , Bakermans‐Kranenburg Marian J. , van IJzendoorn Marinus H. , Velders Fleur P. , Linting Mariëlle , Jaddoe Vincent W.V. , Hofman Albert , Verhulst Frank C. , Tiemeier Henning
Published: May 2012

Maternal discipline is an important predictor of child committed compliance. Maternal stress can affect both parenting and child development. In a large population‐based cohort study (N = 613) we examined whether maternal discipline mediated the association between maternal stress during pregnancy and child compliance, and whether COMT or DRD4 polymorphisms moderated the association between maternal discipline and child compliance. Family‐related and general stress were measured through maternal self‐report and genetic material was collected through cord blood sampling at birth. Mother–child dyads were observed at 36 months in disciplinary tasks in which the child was not allowed to touch attractive toys. Maternal discipline and child compliance were observed in two different tasks and independently coded. The association between family stress during pregnancy and child committed compliance was mediated by maternal positive discipline. Children with more COMT Met alleles seemed more susceptible to maternal positive discipline than children with more COMT Val alleles. © 2012 Wiley Periodicals, Inc. Dev Psychobiol 55: 451–464, 2013