bluuebunny/crossref_metadata_2025 huggingface dataset:
Inductive Proximity Sensor with Novel Structure of Ferrite Core
Authors: Mizuno Tsutomu , Fujii Takayuki , Mizuguchi Takahiro , Kishi Yoshio , Nakaya Katsuhiko , Kasai Masaki , Shimizu Atsushi
Published: December 2010

Inductive proximity sensors (proximity sensors) are noncontact sensing devices used to detect the approach of a target by an increase in coil impedance due to eddy current loss. Extending the operating distance of these sensors is demanded. The flux of a conventional proximity sensor has difficulty in reaching the target because of the presence of the center magnetic pole of ferrite core. Therefore, in this paper, we examine a proximity sensor using a novel structure of ferrite core without the center magnetic pole. In this novel structure, flux easily reaches the target because of the absence of the center magnetic pole. In addition, it is possible to reduce AC resistance due to the proximity effect for the use of a magnetoplated wire. As a result, the operating distance for the novel structure is 1.3-fold that for the conventional structure.
Non-Destructive Evaluation for Internal Defect of Metal Casting
Authors: Nagata Shoichiro , Kai Hisafumi , Enokizono Masato
Published: December 2010

An NDE measurement for internal defects of metal casting products is presented. An experimental system for ECT is developed in order to inspect internal defects of brass casting which have complicated and inaccurate shapes. In the measurement, artificial defect specimen made for fundamental experiments and brass casting specimens are evaluated by multi-frequency excitation and spectrogram (MFES) method. From the results, validity of our measurement system is discussed.
A Coupled System of a Magnet and Magnetic Fluid in a U-Tube under Reciprocating Traveling Magnetic Field
Authors: Ido Yasushi , Hayashi Koichi , Kunitomo Takahiro
Published: December 2010

A coupled system of a magnet and magnetic fluid is used as a piston in a U-tube. Applying reciprocating travelling magnetic field produces reciprocating motion of the coupled system. In this study, vibration properties of the coupled system are investigated experimentally. Three types of vibration mode of the coupled system appear and the mode depends on the frequency and intensity of travelling magnetic field and the shape of the magnet. Basically the coupled system follows the travelling magnetic field in the range of low frequency, while the system cannot follow the travelling field when the frequency of the travelling magnetic field is high. However, when the magnet is sphere or short cylinder, the other type of vibration appears in the range of low frequency and the coupled system intermittently tracks the travelling magnetic field.
Normal Flux Distribution at Step-Lap Joints of Si-Fe Wound Cores
Authors: Kefalas Themistoklis D. , Loizos George , Kladas Antonios G.
Published: December 2010

Even though, the flux distribution at joints of stacked type transformer cores has been investigated thoroughly many issues remain unclear in the case of wound transformer cores. The paper addresses this lack of information by longitudinal and normal flux measurements at step-lap joints of Si-Fe wound cores. Flux measurements are verified by an original finite element analysis where the necessary excitation is performed by means of a pseudo-source. The advantage of the proposed technique is the accurate estimation of the flux distribution at step-lap joints, with a two dimensional model of simple geometry and low computational cost, by using any commercial finite element code.
Magnetostatic Analysis of Multiple-Connected Problems by Boundary Integral Equations
Authors: Ishibashi Kazuhisa , Andjelic Zoran , Pusch David
Published: December 2010

It is studied how to analyze the magnetostatic problems by employing the boundary integral equations. There have been reported a lot of papers about the magnetostatic analysis by these equations. When the permeability is low, most of the magnetostatic problems are solved adequately. However, as the permeability becomes higher, the computed results become poorer especially in the case of the problems without air-gap (multiple-connected problem) or the problem with small air-gap. In order to overcome these difficulties, we derive two new kinds of the boundary integral equations and check their adequacy and effectiveness by solving the multiple-connected problem. Further we investigate their capability to solve the problems concerning the magnetic core with small air-gap.
Evaluation of Hexahedral Mesh Quality for Finite Element Method in Electromagnetics
Authors: Motooka Y. , Noguchi So , Igarashi H.
Published: December 2010

We have previously proposed an automatic hexahedral mesh generator. It is necessary to understand about the quality and characteristic of the generated mesh to perform hexahedral edge finite element analysis in electromagnetic. Therefore, we have compared high-quality meshes with poor-quality meshes, and investigated about the factors that affect the accuracy and the computation time. In addition, we investigated about the effect of the templates used in the proposed method. We will conclusively apply the result to improving the automatic hexahedral mesh generator.
Magneto-Elastic Bilayers for Sleep Apnea Monitoring
Authors: Traxler S. , Pfützner H. , Kaniusas E. , Futschik K.
Published: December 2010

Magneto-elastic bilayers (BLs), consisting of a magnetostrictive layer and a non-magnetic counter layer, show highest sensitivity with respect to bending. This paper describes a biomedical application in the field of sleep apnea screening. A multi-parametric detector fixed at the thorax contains two BLs. One BL yields a skin curvature sensor adjusting itself to curvature variations given by physiological activities. The second BL exhibits a free end thus working as a motion sensor. The two signals are fed into artificial neural networks for the detection of events like normal respiration and apneas, as well as body movements and position.
Effects of Partial Shading on the PV Module Characteristic Curves
Authors: Paraskevadaki Eva , Papathanassiou S. , Vokas Georgios
Published: December 2010

Photovoltaic system performance is influenced by a variety of factors such as irradiance, temperature, shading, degradation, mismatch losses, soiling, etc. Especially shading, complete or partial, can have a significant contribution to the reduction of power output, depending mainly on the PV array configuration, the shading pattern and the existence of bypass diodes incorporated in the PV module design. In order to obtain the maximum power from a PV generator, it is of great importance to evaluate the complex effects of shading on the P-V and I-V curves.
No-Load Loss Modelling of Wound-Core Transformers Using Support Vector Machines and Genetic Algorithms
Authors: Passadis K. , Loizos George , Kladas Antonios G.
Published: December 2010

Accurate estimation of no-load losses is crucial in the transformer design procedure. It saves engineering man-hours, reduces delivery cycle and optimizes the use of core materials. The aim of this paper is to show that Support Vector Machines (SVM) can be successfully used to estimate no load losses.
Construction of Development Technology of Next Generation Applied Electromagnetic Machinery in Japan
Authors: Enokizono Masato
Published: December 2010

The national project of the development technology of next generation applied electromagnetic machinery was founded in Oita as Oita Prefecture Innovative JST (Japan Science and Technology Agency) Research Program. In this paper, outline of this project is introduced and the basic technology which is based on vector magnetic property is described. Especially the vector magnetic properties in high flux density level of 1.9 T are shown. As the example results, the dynamic vector magnetic characteristic is applied to the surface permanent magnet motor.
Surface Induction Hardening Models Based on a Novel Computational Method of Artificial Change of Material Parameters
Authors: Musil Ladislav
Published: December 2010

The paper deals with a novel method suitable for modelling of surface induction hardening and other tasks, where the problem of discretisation of very thin eddy-currents surface layer is present. The method is based on artificial change of material parameters in the computer model. A methodology is suggested and limitations of its application are thoroughly tested. Odds and merits over other possible methods are also discussed.
Magnetization and Giant Negative Magneto-Resistance in Nano-Scale Ni3-δMn1+δ in Pulsed Magnetic Fields up to 25 T
Authors: Yamada Koji , Luo Jiao Lian , Shimoji Hiroyasu , Nakahata Yasusi , Borkowski Edmund Bartosz , Todaka Takashi , Enokizono Masato , Okazaki Teiko
Published: December 2010

Magneto-transport phenomena of slightly Mn-rich sample in the host Ni3-Mn system were investigated on giant-negative magneto-resistance of 15% in pulsed high magnetic fields up to 25 T. We prepared nano-scale crystals of Nin (0≤≤0.05) fabricated by rapid quenching method with a mono-role and by optimum annealing to obtain the maximum magneto-resistance effect in the longitudinal configuration of sample currents and magnetic fields. The negative magneto-resistance observed in this study was interpreted as the scattering decrease of conduction electrons by anti-parallel spin pairs composed of Mn-Mn deviated from the stoichiometry. This physical mechanism also reflects the coherent length change of itinerant electrons, caused by the scattering by the comparable short-range spin disorder of Mn-Mn pairs in the nano-scale crystal grain.
Exchange-Induced Magnetic Dipole Mechanism of Magnon Sideband
Authors: Eremin Mikhail V. , Deisenhofer Joachim , Fayzullin M.A. , Kant C. , Loidl Alois
Published: December 2010

We propose a new mechanism of exciton-magnon absorption in the 1D Heisenberg antiferromagnet KCuF3. It yields the correct description of the relative intensity of the spectral lines in both polarizations E c and E‖c. The magnon density of states has been calculated. The origin of the fine sideband structure in KCuF3 can be explained. The sharp magnon lines, observed in Ref. [1], correspond to the low energy singularities in the magnon density of states.
Magnetocaloric Effect of RCo5 Single Crystals in the Region of Spin-Reorientation Transitions
Authors: Koshkid’ko Y.S. , Skokov Konstantin , Pastushenkov Yury G. , Nikitin S.A. , Ivanova T.I.
Published: December 2010

Direct measurements of the magnetocaloric effect (MCE) in RCo5 single crystals in the region of spin-reorientation transitions (SRT) were carried out. It was shown that the values of MCE in the region of SRTs are comparable to the values of MCE in the vicinity of the Curie temperature. The anisotropy constants of the compounds were measured by the torque method. The anisotropic MCE calculation on the basis of anisotropy constants showed a good accordance with the experimental data.
Transition from Itinerant Electron Magnetism to Localized Spin Magnetism in Ni3Al1-YMny Alloys
Authors: Korolyov A.V. , Kourov N.I. , Nazarova S.Z. , Dorofeev Y.A. , Volkova N.V. , Belozerov E.V.
Published: December 2010

Magnetic properties of Ni3Al1-yMny alloys at y≤0.6 were investigated at T≤400 K in magnetic fields H≤4 MA/m. The concentration y dependencies of the spontaneous magnetic moment s, the effective magnetic moment eff, the Curie temperature ТС, the Weiss constant , and the temperature independent part of the magnetic susceptibility 0 were determined. The behavior of the Rhodes-Wohlfarth parameter р(y) in the transition region from the itinerant electron magnetism to the spin localized one is related to the increase in the spontaneous magnetic moment of Ni atoms inversely proportional to the average distance between Mn atoms with the highly localized magnetic moments.
Interlayer Coupling in Co/Ge/Co Trilayers
Authors: Kobyakov A.V. , Patrin G.S. , Turpanov I.A. , Li L.A. , Patrin K. G. , Yushkov V.I. , Petrakovskaya E.A. , Rautskii M.V.
Published: December 2010

The interlayer coupling in Co/Ge/Co trilayer films has been experimentally studied by the SQUID magnetometry and electron magnetic resonance. It has been found that the interlayer coupling is temperature-dependent. The values of the exchange constants have been determined.
Magnetic Properties of Plasma Electrolytic Iron-Containing Oxide Coatings on Aluminum and Simulation of Demagnetizing Process
Authors: Rudnev V. , Ustinov A. , Lukiyanchuk I. , Kharitonskii P. , Frolov A. , Morozova V. , Tkachenko I. , Adigamova M.
Published: December 2010

Magnetic properties of iron-containing coatings obtained on aluminum by plasma electrolytic oxidation were analyzed in this paper. Theoretical curves of demagnetization of these objects are obtained. It is shown that the magnetic states of the analyzed samples can be caused by the presence of several phases with very different magnetic properties.
Giant Drop of Magnetic Hysteresis with Decreasing Thickness of Cr-Buffer Layer of CoFe/Cu Superlattices
Authors: Milyaev M.A. , Naumova L.I. , Proglyado V.V. , Krinitsina T.P. , Bannikova N.S. , Ustinov V.V.
Published: December 2010

The effect of Cr-buffer-layer thickness on the structure, giant magnetoresistance, and coercivity of DC sputtered Cr(tCr)/[Co90Fe10(15Å)/Cu(23Å)]8/Cr(10Å) superlattices has been investigated. A drastic change of hysteresis in a short interval of the buffer layer thickness (15 ÷ 20 Å) has been revealed. It has been shown that in superlattices with low coercivity the (111) texture is present, whereas superlattices without texture demonstrate a large coercivity and high GMR ratio.
Determination of Selective Concentration Profile and Depth Resolved Partial Atomic Distributions for Multilayer Nanoheterostructures
Authors: Babanov Yu.A. , Salamatov Yu.A. , Mukhamedzhanov E. Kh.
Published: December 2010

A new method for studying multilayer structure using angle resolved XAFS measurements is proposed. The integral equation describing the relation between the fluorescence intensity for selective spectrum, the incident beam energy, the incident angle and a selective concentration profile, depth-dependent EXAFS has been derived. This integral Fredholm equation of the first kind belongs to the class of ill-posed problems and for the solution it needs special methods. We use the regularization Tikhonov method. The effectiveness of the proposed method was tested using the numerical simulations for trilayer system Cr-Fe-Cr. Some first experimental results for the thin films of pure Cr are also presented.
Size Effect in Nix(MgO)100-X Nanocomposites
Authors: Grebennikov A.A. , Stognei O.V.
Published: December 2010

The possibility of obtaining a nanostructured composite in the Ni-Mg-O system by ion-beam sputtering has been investigated. The structural, magnetic and magnetoresistive properties of obtained samples have been investigated in a wide concentration range. The presence of the nanostructure in the obtained samples with Ni nanogranules (2-3 nm) has been confirmed by transmission electron microscopy. There is no observation of any magnetic or magnetoresistive properties at room temperature in the Nix(MgO)100-x composites. These properties were observed at 77 K. The obtained data mean that Curie temperature of the Ni nanogranules is lower then 298 K. This is due to small size of nickel granules and low value of exchange interaction energy in nickel.
Magnetocaloric Effect in Sm0.55Sr0.45MnO3 Manganite
Authors: Zashchirinskii D.M. , Morozov A.S. , Koroleva L.I. , Balbashov A.M.
Published: December 2010

Magnetocaloric effect (T-effect) was studied by direct method on three samples of Sm0.55Sr0.45MnO3 manganite: ceramic (C) sample and two single crystals, annealed in oxygen (O) or in air atmosphere (A). The temperature dependence of T-effect T(T) of all the samples has maximum at Tmax equal to 143.3 K for A-sample, 244 K for O-sample, and 143 K for C-sample. In these maxima T values are 0.8 K, 0.41 K, and 0.4 K for A-, O- and C-samples respectively. In addition, the T(T) curve of A-sample has minimum at Tmin = 120 K and T-value in minimum is equal to - 0.1 K. The maximum value of T-effect increases with H up to the maximum field of measurement 14.2 kOe. When this takes place the rate of this increasing is higher at H > 8 kOe than at H < 8 kOe. The above listed peculiarities of T-effect are explained by the presence in the samples of ferromagnetic, antiferromagnetic A-type and antiferromagnetic CE-type clusters.
Magnetic Properties of New Diluted Magnetic Semiconductors Pb1-X-YMgXYbYTe
Authors: Zvereva E.A. , Savelieva O.A. , Ibragimov S. , Titov Y. , Slynko E.I. , Slyn’ko V.
Published: December 2010

We have studied the magnetic susceptibility, magnetization and electron paramagnetic resonance (EPR) in the diluted magnetic semiconductor Pb1-x-yMgxYbyTe. The magnetic susceptibility of this system is a superposition of the matrix diamagnetism, the paramagnetic contribution of electrons localized in the ytterbium band, and the Curie-Weiss paramagnetism provided by Yb3+ ions. The concentration of Yb3+ ions monotonically increases with the ytterbium content, while a significant fraction of ytterbium ions remains in a nonmagnetic Yb2+ state. A pronounced hyperfine structure was revealed in the EPR spectra. It was ascribed to the interaction between the electron magnetic moment of an unfilled electron shell of Yb3+ ions and nuclear magnetic moment of the 173Yb isotope. The estimated values of the effective g-factor (g1.997 0.002) and the hyperfine-interaction constant (173A=0,56 cm-1) were found to be almost independent of both alloy composition and temperature.
Magnetic Properties and Temperature Stability of Nanocrystalline Fe-Based Soft Magnetic Alloys
Authors: Noskova N.I. , Shulika V.V. , Potapov A.P.
Published: December 2010

The effect of the nanocrystallization conditions on the structure, magnetic characteristics and temperature stability of the Fe73.5Cu1Nb3Si13.5B9, Fe73.5Cu1Nb1.5Мo1.5Si13.5B9, Fe69Cu1Nb1.5Мo1.5Si13.5B9Co4.5, and (Fe0.6Co0.4)86Hf7B6Cu1 nanocrystalline soft magnetic alloys has been analyzed. The samples were nanocrystallized in the absence of a field, in a dc or ac magnetic field. It has been shown that the Fe73.5Cu1Nb1.5Мo1.5Si13.5B9 alloy has unique magnetic properties and a high temperature-time stability. It has been found that nanocrystallization of the (Fe0.6Co0.4)86Hf7B6Cu1 amorphous alloy in an ac magnetic field considerably improves its static and dynamic magnetic properties.
Phase Transformations in Ferromagnetic Nanostructured FePd Alloy under Severe Plastic Deformation and Annealing
Authors: Vlasova N.I. , Gaviko V.S. , Popov A.G. , Shchegoleva N.N. , Stashkova L.A. , Gunderov Dmitriy , Sauvage Xavier
Published: December 2010

Equiatomic FePd alloy in the ordered state has been processed by means of high-pressure torsion deformation (HPTD) and then annealed. X-ray diffraction (XRD), transmission electron microscopy (TEM), and magnetic measurements have been carried out. HPTD results in an order-disorder transformation of the initial ordered L10-phase (s.g. P4/mmm) into a disordered fcc phase (s.g. Fm-3m) through the body-centered tetragonal (bct) phase (s.g. I4/mmm). Subsequent annealing restores the L10-phase.
Ferromagnetism in the Highly-Correlated Hubbard Model
Authors: Irkhin Valentin Yu. , Zarubin Alexander V.
Published: December 2010

The Hubbard model with strong correlations is treated in the many-electron representation of the Hubbard's operators. The regions of stability of saturated and non-saturated ferromagnetism in the n–U plane for the square and simple cubic lattices are calculated. The role of the singularities of bare density of states for the magnetic phase diagram is discussed. A comparison with the results of previous works is performed.
Electronic Transport in Itinerant Metamagnets with Strong Static Disorder
Authors: Burkov A.T. , Nakama T. , Yagasaki K.
Published: December 2010

We report on electronic transport in nearly magnetic conductors with strong structural disorder. The initial motivation for this work was a large positive magnetoresistance (MR) found in magnetically ordered ground state of (Y1-xGdx)Co2 alloys. This was a surprising result since a large positive MR is not expected in a system with strong static magnetic or structural disorder. Contemporary theory of magnetotransport and common sense agree that an external magnetic field should suppress magnetic fluctuations, resulting in a negative MR. On the contrary; a positive MR suggests that an external magnetic field enhances static magnetic disorder. It was shown that unusual MR of (Y1-xGdx)Co2 alloys is related to a combination of structural disorder and metamagnetic instability of itinerant Co-3d electrons. The new mechanism of MR is common of a broad class of materials featuring a static magnetic disorder and itinerant metamagnetism. Such systems display a number of unusual properties, among them strong pressure and magnetic field dependencies of resistivity and thermopower, Non-Fermi-Liquid (NFL) behavior of resistivity and, possibly, of thermopower. We review the relevant experimental data, mostly the properties of RCo2-based alloys, and discuss the theoretical model developed for the interpretation of the experimental results. This model includes new mechanism of magnetoresistivity in structurally disordered itinerant magnetic alloys.
Optical Properties and Electronic Structure of LaNi5-XCux (x=0–1.2) Intermetallic System
Authors: Knyazev Yu.V. , Kuz’min Y.I. , Lukoyanov A.V. , Kuchin Anatoly G.
Published: December 2010

Optical properties of the LaNi5-xCux (x = 0, 0.6, 1, 1.2) compounds were studied. It was shown that substitution of copper for nickel led to noticeable changes in the optical conductivity spectra. Calculations of the electronic structure of compounds with x = 0, 1, 2 were performed using a generalized gradient approximation. The interband optical conductivity of these intermetallics was calculated. The optical ellipsometrical measurements and theoretical calculations testify to the appearance of a broad absorption structure associated with the Cu 3d  Ni 3d electron transitions and increasing with the growth of copper content.
The Features of TKE and FMR in Nanocomposite-Semiconductor Multilayers
Authors: Buravtsova Victoria , Gan'shina E.A. , Lebedeva E. , Syr’ev N. , Trofimenko I. , Vyzulin S. , Shipkova I. , Phonghirun S. , Kalinin Y. , Sitnikov A.V.
Published: December 2010

Magnetic and magneto-optical properties of multilayers based on the (Co45Fe45Zr10)Z(Al2O3)100-Z composite and amorphous hydrogenated silicon with various thicknesses both of magnetic and semiconductor layers have been investigated. The nonlinear dependence of magnetic and MO characteristics of the nanostructures on the thickness of layers was found. The interface formed on the boundary of two phases (the ferromagnetic granules and the semiconductor ones) strongly influences the magnetic and MO properties of the structures with thin Si layers.
Collective Magnetic Moment Relaxation in an Assembly of Ferromagnetic Nanoparticles
Authors: Henner V.K. , Raikher Yu.L. , Kharebov P.V.
Published: December 2010

The idea of establishing coherent relaxation in an assembly of magnetic moments by placing it in a passive resonator [1, 2] is applied to the case of single-domain ferromagnetic nanoparticles. The magnetodynamics of a particle is governed by the Landau-Lifshitz equation modified by adding the resonator feedback field. The particle uniaxial magnetic anisotropy and the interparticle dipole-dipole interactions are taken into account.
Autoresonance Excitation of Nonlinear Oscillations of Magnetization and Domain Walls in Ferromagnets
Authors: Kharisov A.T. , Kalyakin L.A. , Shamsutdinov M.A.
Published: December 2010

We investigate the conditions of capturing into resonance and exciting nonlinear ferromagnetic resonance in a ferromagnetic film with the anisotropic easy plane, as well as autoresonance excitation of nonlinear oscillations of the domain wall in uniaxial ferromagnets. The investigations demonstrate that in easy-plane ferromagnets with a narrow resonance line nonlinear oscillations of magnetization in the autoresonance mode can be generated. This autoresonance takes place if the resonance field grows slowly and pumping frequency is the constant which is equal to the frequency of linear resonance. It has been established that effectively exciting nonlinear oscillations of the domain wall in uniaxial ferromagnets and controlling the wall dynamics by low-amplitude alternating fields with the slow variation of the planar field in the autophasing mode are possible in the case of weak dissipation.
Correlation of Copper Interaction, Copper‐Driven Aggregation, and Copper‐Driven H2O2 Formation with Aβ40 Conformation
Authors: Yang Chia-Anne , Chen Yung-Han , Ke Shyue-Chu , Chen Yi-Ru , Huang Hsien-Bin , Lin Ta-Hsien , Chen Yi-Cheng
Published: December 2010

The neurotoxicity of Aβ is associated with the formation of free radical by interacting with redox active metals such as Cu2+. However, the relationship between ion‐interaction, ion‐driven free radical formation, and Aβ conformation remains to be further elucidated. In the present study, we investigated the correlation of Cu2+ interaction and Cu2+‐driven free radical formation with Aβ40 conformation. The Cu2+‐binding affinity for Aβ40 in random coiled form is 3‐fold higher than that in stable helical form. Unexpectedly but interestingly, we demonstrate in the first time that the stable helical form of Aβ40 can induce the formation of H2O2 by interacting with Cu2+. On the other hand, the H2O2 generation is repressed at Aβ/Cu2+ molar ratio ≥1 when Aβ40 adopts random coiled structure. Taken together, our result demonstrates that Aβ40 adopted a helical structure that may play a key factor for the formation of free radical with Cu2+ ions.
A Factor Analytic Approach to Symptom Patterns in Dementia
Authors: Gustafson Lars , Erikson Catarina , Warkentin Siegbert , Brun Arne , Englund Elisabet , Passant Ulla
Published: December 2010

Previous publications have shown a high diagnostic sensitivity and specificity of three short clinical rating scales for Alzheimer′s disease (AD), frontotemporal dementia (FTD), and vascular dementia (VaD) validated against neuropathological (NP) diagnoses. In this study, the aim was to perform an exploratory factor analysis of the items in these clinical rating scales. The study included 190 patients with postmortem diagnoses of AD (n = 74), VaD (n = 33), mixed AD/VaD (n = 31), or FTD (n = 52). The factor analysis produced three strong factors. Factor 1 contained items describing cerebrovascular disease, similar to the Hachinski Ischemic Score. Factor 2 enclosed major clinical characteristics of FTD, and factor 3 showed a striking similarity to the AD scale. A fourth symptom cluster was described by perception and expression of emotions. The factor analyses strongly support the construct validity of the diagnostic rating scales.
A Longitudinal Study of the Family Physical Activity Environment and Physical Activity among Youth
Authors: Cleland Verity , Timperio Anna , Salmon Jo , Hume Clare , Telford Amanda , Crawford David
Published: December 2010

Purpose.

Although the family environment is a potentially important influence on children's physical activity (PA), prospective data investigating these associations are lacking. This study aimed to examine the longitudinal relationship between the family environment and PA among youth.

Design.

A 5-year prospective cohort study.

Setting.

Nineteen randomly selected public schools in Melbourne, Australia.

Subjects.

Families of 5- to 6-year-old (n = 190) and 10- to 12-year-old (n = 350) children.

Measures.

In 2001, parents reported their participation in PA, family-based PA, and support and reinforcement for their child's PA. In 2001, 2004, and 2006, moderate to vigorous intensity PA (MVPA) was assessed among youth using accelerometers. Weekend and “critical window” (after school until 6:00 P.M.) MVPA were examined because we hypothesized that the family environment would most likely influence these behaviors.

Analysis.

Generalized estimating equations predicted average change in MVPA over 5 years from baseline family environment factors.

Results.

Maternal role modeling was positively associated with boys' critical window and weekend (younger boys) MVPA. Paternal reinforcement of PA was positively associated with critical window and weekend MVPA among all boys, and paternal direct support was positively associated with weekend MVPA (older boys). Among girls, maternal coparticipation in PA predicted critical window MVPA, and sibling coparticipation in PA was directly associated with weekend MVPA (younger girls).

Conclusions.

Longitudinal relationships, although weak in magnitude, were observed between the family environment and MVPA among youth. Interventions promoting maternal role modeling, paternal reinforcement of and support for PA, and maternal and sibling coparticipation in PA with youth are warranted. (Am J Health Promot 2011;25[3]:159–167.)
A Sequence of Critical Thinking Tasks
Authors: BEAUMONT JOHN
Published: December 2010

Critical thinking skills remain at the forefront of educational discussions. These higher order thinking processes, including but not limited to reflection, inference, and synthesizing information, enable individuals to make reasoned judgments not only in the classroom but in everyday life. School systems demand that critical thinking be incorporated into curricula, and standardized testing increasingly assesses it. However, there remains the question of how English language teachers include the development and practice of these important skills in their lessons. To this end, this article presents a sequence of seven critical thinking tasks, a flexible framework that acts as a practical tool for planning and developing level‐appropriate classroom materials that encourage and advance critical thinking. The sequence of tasks, originated by Carol Numrich at Columbia University, guides teachers in scaffolding critical thinking and English language skills so that critical thinking may be practiced at any language proficiency level.
High‐Stakes Testing and English Language Learners: Using Culturally and Linguistically Responsive Literacy Practices in the High School English Classroom
Authors: GIOUROUKAKIS VICKY , HONIGSFELD ANDREA
Published: December 2010

This multicase study investigated the impact of high‐stakes testing on the literacy practices of teachers of high school English language learners (ELLs) in three Long Island, New York, school districts, in one of the most racially and socioeconomically segregated regions of the United States. The goal of the study was to explore what kinds of literacy tasks and materials were implemented in order to develop ELLs' literacy skills and prepare them to be successful on the state's high‐stakes English exam. Findings indicate that all four teachers participating in the study engaged in (a) instructional activities and materials that directly prepared students for the state's high‐stakes exam (teaching to the test) and (b) culturally and linguistically responsive practices. It is also apparent from the data that teachers were addressing the duality of helping students succeed on the exam and preparing them to become lifelong learners by reflecting on the impact of high‐stakes testing on students' diverse needs.
Teaching the concept of management: Perspectives from ‘six honest serving men’
Authors: McDonald Paul
Published: December 2010

Management as a body of knowledge is dynamic such that management educators face continual challenges to achieve realism and relevance in the classroom. The emerging knowledge economy, in parallel with accelerating changes in technology, globalization and societal values, make these challenges more acute than ever before. The purpose of this article is to provide personal insights using a framework for analyzing and teaching management that draws on Rudyard Kipling's ‘six honest serving men’—what, why, when, how, where and who. These ‘honest serving men’ trigger discrete perspectives with which we can analyze, revise and recalibrate the teaching of management to ensure that it remains relevant to modern business. Teaching propositions are advanced as to management's definition.
Teaching organizational power and politics through a critical pedagogical approach
Authors: Duarte Fernanda
Published: December 2010

Re-visiting the ideas of some key educational thinkers and critical management theorists, this paper re-affirms the need for a critical pedagogy of organizational power and politics to foster deeper levels of reflection and ethical attitudes among undergraduate management students. While prescriptive pedagogical approaches can impart knowledge that may be useful to future managers, they often encourage a shallow and instrumental view of power in which profits are placed above ethics, and expediency above morality. As argued here, a critical pedagogy will encourage a more productive analysis of power-related phenomena in organizations, and will nurture attitudes and behaviours that can humanize management practice. The first part of the paper examines the key theoretical concepts of the proposed approach, the second discusses a set of themes emerging from a critical analysis of organizational power and politics in a management subject, and the third discusses common challenges encountered by academics committed to critical approaches.
Reduction-in-force (RIF) – New developments and a brief historical analysis of a business strategy
Authors: Gandolfi Franco , Hansson Magnus
Published: December 2010

After nearly three decades of corporate restructurings and reorganizations, the modern firm has continued to resort to reduction-in-force (RIF) strategies. This article presents an overview and a brief historical analysis of some of the most popular RIF concepts that have been adopted by companies and governmental agencies on a global scale since the late 1970s. The research found that most RIF tools have their root in the core-periphery model. While some of the more ‘classic’ RIF strategies have remained popular, the paper showcases two contemporary practices, the traditional (non-selective) layoffs and stealth layoffs, that currently impact the corporate landscape. A discussion of modern-day restructuring and RIF practices is timely given the high levels of layoffs currently occurring in the global automotive, retail, and finance-related industries. In this paper, a particular focus is placed on presenting practical implications of the conduct of RIF for the firm, the managers, and the individual employees.
Physical properties of iodate solutions and the deliquescence of crystalline I2O5 and HIO3
Authors: Kumar R. , Saunders R. W. , Mahajan A. S. , Plane J. M.C. , Murray B. J.
Published: December 2010

Abstract. Secondary aerosol produced from marine biogenic sources in algal-rich coastal locations will initially be composed of iodine oxide species, most likely I2O5, or its hydrated form HIO3, formed as a result of iodine gas-phase chemistry. At present, there is no quantitative hygroscopic data for these compounds and very little data available for iodate solutions (HIO3 and I2O5 share a common aqueous phase). With increased interest in the role of such aerosol in the marine atmosphere, we have conducted studies of (i) the deliquescence behaviour of crystalline HIO3 and I2O5 at 273–303 K, (ii) the efflorescence behaviour of aqueous iodate solution droplets, and (iii) properties (water activity, density, and viscosity) of subsaturated and saturated iodate solutions. The deliquescence of I2O5 crystals at 293 K was observed to occur at a relative humidity (DRH) of 80.8±1.0%, whereas for HIO3, a DRH of 85.0±1.0% was measured. These values are consistent with measured water activity values for saturated I2O5 and HIO3 solutions at 293 K of 0.80±0.01 and 0.84±0.01 respectively. At all temperatures, DRH values for HIO3 crystals were observed to be higher than for those of I2O5. The temperature-dependent DRH data, along with solubility and water activity data were used to evaluate the enthalpy of solution (ΔHsol) for HIO3 and I2O5. A ΔHsol value of 8.3±0.7 kJ mol−1 was determined for HIO3 which is consistent with a literature value of 8.8 kJ mol−1. For I2O5, we report for the first time its solubility at various temperatures and ΔHsol = 12.4±0.6 kJ mol−1. The measured water activity values confirm that aqueous iodate solutions are strongly non-ideal, consistent with previous reports of complex ion formation and molecular aggregation.
Measurements of HONO during BAQS-Met
Authors: Wentzell J. J. B. , Schiller C. L. , Harris G. W.
Published: December 2010

Abstract. Measurements of nitrous acid (HONO) were performed as part of the 2007 Border Air Quality and Meteorology Study (BAQS-Met) at the Harrow, Ontario, Canada supersite between 20 June and 10 July 2007. Nitrous acid is an important precursor of the hydroxyl radical and understanding its chemistry is important to understanding daytime oxidation chemistry. The HONO measurements were made using a custom built Long Path Absorption Photometer (LOPAP). The goal of this work was to shed light on sources of daytime HONO in the border region. During the course of the campaign HONO mixing ratios consistently exceeded expected daytime values by more than a factor of 6. Mean daytime mixing ratios of 61 pptv were observed. While HONO decay began at sunrise, minimum HONO values were measured during the late afternoon. There was little difference between the daytime (mean = 1.5%) and night-time (mean = 1.7%) ratios of HONO/NO2, thus there was a very strong daytime source of HONO which is consistent with other recent studies. Correlations of daytime HONO production with a variety of chemical and meteorological parameters indicate that production is dependent on UV radiation, NO2 and water vapour but is not consistent with a simple gas phase process. Apparent rate constants for the production of HONO from photolyticaly excited NO2 and water vapour vary from 2.8–7.8×10−13 cm3 molec−1 s−1, during the campaign. These results appear to be consistent with the heterogeneous conversion of NO2 enhanced by photo-excitation.
Investigation of Energy Transfer in Organic Photovoltaic Cells and Impact on Exciton Diffusion Length Measurements
Authors: Luhman Wade A. , Holmes Russell J.
Published: December 2010

This work demonstrates an approach for measuring the Förster radius of energy transfer between electron donating and accepting materials commonly used in organic photovoltaic cells (OPVs). While energy transfer processes are surprisingly common in OPVs, they are often incorrectly ignored in measurements of the exciton diffusion length and in models of device performance. Here, the efficiency of energy transfer between an emissive donor and an absorptive acceptor is investigated through complementary experimental and theoretical techniques. This is accomplished by spatially separating the donor and acceptor materials using a wide‐energy‐gap spacer layer to suppress direct charge transfer and tracking donor photoluminescence as a function of spacer layer thickness. Fitting experimental data obtained for a variety of donor materials allows for the extraction of Förster radii that are in good agreement with predicted values. The impact of donor–acceptor excitonic energy transfer on device performance and on measurements of the exciton diffusion length is also investigated using the archetypical small molecule donor material boron subphthalocyanine chloride (SubPc). An average exciton diffusion length of 7.7 nm is extracted from photoluminescence quenching experiments using SubPc. This value is independent of the quenching material when the role of energy transfer is properly modeled.
Nanoparticles: Correlation Between Surface Chemistry and Electrocatalytic Properties of Monodisperse PtxNi1‐x Nanoparticles (Adv. Funct. Mater. 1/2011)
Authors: Wang Chao , Chi Miaofang , Wang Guofeng , van der Vliet Dennis , Li Dongguo , More Karren , Wang Hsien‐Hau , Schlueter John A. , Markovic Nenad M. , Stamenkovic Vojislav R.
Published: December 2010

Monodisperse and homogeneous PtxNi1‐x alloy nanoparticles of various compositions are synthesized via an organic solution approach in order to reveal the correlation between surface chemistry and their electrocatalytic properties. Atomic‐level microscopic analysis of the compositional profile and modeling of nanoparticle structure are combined to follow the dependence of Ni dissolution on the initial alloy composition and formation of the Pt‐skeleton nanostructures. The developed approach and acquired knowledge about surface structure‐property correlation can be further generalized and applied towards the design of advanced functional nanomaterials.
Photovoltaic Devices: High‐Performance Organic Solar Cells with Spray Coated Hole‐Transport and Active Layers (Adv. Funct. Mater. 1/2011)
Authors: Girotto Claudio , Moia Davide , Rand Barry P. , Heremans Paul
Published: December 2010

In this study, we report high performance organic solar cells with spray coated hole‐transport and active layers. With optimized ink formulations we are able to deposit films with controlled thickness and very low surface roughness (<10 nm).

Specifically we deposit smooth and uniform 40 nm thick films of poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as well as films composed of a mixture of poly(3‐hexyl thiophene) (P3HT) and the C60‐derivative (6,6)‐phenyl C61‐butyric acid methyl ester (PCBM) with thicknesses in the range 200–250 nm.

To control film morphology, formation and thickness, the optimized inks incorporate two solvent systems in order to take advantage of surface tension gradients to create Marangoni flows that enhance the coverage of the substrate and reduce the roughness of the film.

Notably, we achieve fill factors above 70% and attribute the improvement to an enhanced P3HT crystallization, which upon optimized post‐drying thermal annealing results in a favorable morphology. As a result, we could extend the thickness of the layer to several hundreds of nanometers without noticing a substantial decrease of the transport properties of the layer.

By proper understanding of the spreading and drying dynamics of the inks we achieve spray coated devices with power conversion efficiency of 3.75%, with fill factor, short circuit current and open circuit voltage of 70%, 9.8 mA cm−2 and 550 mV, respectively.
On the Manifestation and nature of macroinstabilities in stirred vessels
Authors: Doulgerakis Zacharias , Yianneskis Michael , Ducci Andrea
Published: December 2010

The flow variations or macroinstabilities (MIs) occurring in a vessel stirred by a pitched blade turbine (PBT) are studied through particle image velocimetry (PIV) experiments. Proper orthogonal decomposition and fast Fourier transform techniques are applied to the PIV velocity data at one vertical and nine horizontal planes below the impeller, to identify and characterize the flow structures present in the vessel. It is shown that the PBT MI is manifested as a precessional movement around the impeller axis and an oscillation in the direction of the axial mean stream around the shaft axis. The identified flow structures are similar to those previously observed in vessels stirred by Rushton impellers and are characterized by two dominant frequencies, equal to one‐tenth and one‐fifth of the impeller rotational speed. The nature and extent of these structures and their interaction with the trailing vortices emanating from the turbine blades are discussed. © 2011 American Institute of Chemical Engineers AIChE J, 2011
Control and enhancement of permselectivity of membrane‐based microcapsules for favorable biomolecular transport and immunoisolation
Authors: Ranganath Sudhir H. , Ling Tan Ai , He Fang , Wang Chi‐Hwa , Krantz William B.
Published: December 2010

The success of membrane‐based, cell‐encapsulating microcapsules depends on the membrane permselectivity that provides efficient inward transport of nutrients, therapeutic protein egress, and complete exclusion of immunoglobulins. Microcapsules with a calcium crosslinked alginate core and a genipin‐crosslinked chitosan alginate (GCA) were prepared with good control over size, membrane thickness and density. Importantly, in this study, we report a novel approach of using three relevant biomolecules and investigating the effects of the membrane characteristics (thickness and density) and microcapsule size on biomolecular mass transport across the GCA microcapsules using mathematical models based on a balance of the chemical potential. Scaling analysis was used to interrelate the membrane thickness, chitosan–alginate reaction rate constant, and diffusion coefficient. The resistance to diffusion of the three biomolecules increased with membrane density and thickness. Interestingly, swelling in the large microcapsules resulted in an increase in permeability, allowing larger biomolecules (immunoglobulin and carbonic anhydrase) to diffuse more readily. In the case of the smaller biomolecule, vitamin B12, a shorter diffusion path length in smaller microcapsules allowed better ingress. When compared with other microcapsules, the GCA microcapsules possess improved permselectivity for them to allow diffusion of small nutrient molecules and proteins, whereas completely excluding antibodies. Also, these results elucidate the importance of membrane properties and microcapsule size to realize favorable transport of biomolecules. © 2011 American Institute of Chemical Engineers AIChE J, 2011
Numerical simulation of three‐dimensional gas‐solid particle flow in a horizontal pipe
Authors: Kartushinsky A. I. , Michaelides E. E. , Rudi Y. A. , Tisler S. V. , Shcheglov I. N.
Published: December 2010

A three‐dimensional model of particulate flows using the Reynolds Averaged Navier‐Stokes method is presented. The governing equations of the gas–solids flow are supplemented with appropriate closure equations to take into account all the relevant forces exerted on the solid particles, such as particle‐turbulence interactions, turbulence modulation, particle–particle interactions, particle–wall interactions, as well as gravitational, viscous drag, and lift forces. A finite volume numerical technique was implemented for the numerical solution of the problem. The method has been validated by comparing its results with the limited number of available experimental data for the velocity and turbulence intensity of the gas–particle flow. The results show that the presence of particles in the flow has a significant effect on all the flow variables. Most notably, the distribution of all the parameters becomes asymmetric, because of the gravitational effect on the particles and particle sedimentation. © 2011 American Institute of Chemical Engineers AIChE J, 2011
Kinetic theory of aggregation in granular flow
Authors: Liu L.
Published: December 2010

This article presents a mathematical formulation of the aggregation kinetics in granular flow. The traditional kinetic theory and its generalized application to granular flow does not allow for particle size to change with time thus cannot be used to describe particle flow with aggregation taking place. In this article, a collision success factor, quantifying the completely inelastic collision of particles, is introduced into the evaluation of collision rate. The kinetic transport equations are then transformed to include source terms that account for the effects of particle size and aggregation. The analytical solution of the collision success factor is obtained by integrating the relative velocity distribution function over its velocity domain from 0 to a critical value, which corresponds a balance between the repulsion and attraction forces in a collision. The factor has been found to depend on the mixture granular energy and the critical relative collision energy. © 2011 American Institute of Chemical Engineers AIChE J, 2011