bluuebunny/crossref_metadata_2025 huggingface dataset:
Legal Status of the Budgetary Guarantees in Ukraine and Kazakhstan
Authors: Zykov Roman , Mulder Harm
Published: October 2006

This article contains the analysis of developments in the budgetary legislation, which occurred during the last decade in Ukraine and Kazakhstan. In essence, the article focuses on the matters of provision of guarantees by the local authorities. The authors take a look at the evolution of the constitutional, budgetary, financial, civil and administrative legislation in connection to the issues of the budgetary guarantees in the both countries. Employing a comparative approach, the authors draw parallels between two independently developing legal systems which share a common legislative past.
Neutron Techniques for Welding Project Methods Development in Nuclear/Traditional Industrial Applications
Authors: Rogante M. , Lebedev V.T. , Kralj S. , Rosta L. , Törö
Published: October 2006

This paper addresses important technical problems related with methodological limitations of welding project methods currently adopted, mostly regarding numerical modelling procedure of welding processes. The progress in high nano‐technologies give rise to the same approaches to be applied in traditional mechanics and material science, really concerning welding processes using various methods and techniques. Recent investigations of welded joints have shown the benefits related to the employment of neutron techniques, to obtain substantial information advancing quality and durability that cannot be found by using other means. Small Angle Neutron Scattering (SANS) and Neutron Diffraction (ND), in particular, consent materials characterization at atomic and nanoscale level, offering to the existing technologies the essential contribution of precise structural methods. The basic theoretical aspects are described, and some SANS investigations of weldments are reported. An experimental programme has been recently projected to develop welding processes, with quality assurance improvement, safety enhancement, life‐time management and cost effectiveness of the considered joints.
Mechanical and Microstructural Behaviour of 6061/AL
Authors: Cavaliere P.
Published: October 2006

The aim of the present paper was the study of mechanical and microstructural behaviour of 6061/Al2O3/20p metal matrix composite sheets joined by Friction Stir Welding. The material was welded into the form of sheets of 7 mm thickness after T6 treatment and was tested in tension and fatigue at room temperature. The mechanical behaviour of the material was found to depend strongly on the particles fracture across the weld. The tensile properties in longitudinal direction resulted higher respect to the transversal ones. The fatigue endurance (S‐N) curve of the welds was obtained by using a resonant electro‐mechanical testing machine under constant loading control up to 250 Hz sine wave loading. The cyclic fatigue tests were conducted in the axial total stress‐amplitude control mode with min max R = σ / σ The microstructure resulting from the FSW process was studied by employing optical and scanning electron microscopy.
A Computational Analysis of Detonation of Buried Mines
Authors: Grujicic M. , Pandurangan B. , Cheeseman B. A.
Published: October 2006

A nonlinear‐dynamics transient computational analysis of the explosion phenomena associated with detonation of 100g of C4 high‐energy explosive buried at different depths in sand is carried out using the AUTODYN computer program. The results obtained are compared with the corresponding experimental results obtained in Ref. [1]. To validate the computational procedure and the materials constitutive models used in the present work, a number of detonation‐related phenomena such as the temporal evolutions of the shape and size of the over‐burden sand bubbles and of the detonation‐products gas clouds, the temporal evolutions of the side‐on pressures in the sand and in air, etc. are determined and compared with their experimental counterparts. The results obtained suggest that the agreement between the computational and the experimental results is reasonable at short postdetonation times. At longer post‐detonation times, on the other hand, the agreement is less satisfactory primarily with respect to the size and shape of the sand crater, i.e. with respect to the volume of the sand ejected during explosion. It is argued that the observed discrepancy is, at least partly, the result of an inadequacy of the generic materials constitutive model for the sand which does not explicitly include the important effects of the sand particle size and the particle size distribution, as well as the effects of moisture‐level controlled inter‐particle friction and cohesion. It is further shown that by a relatively small adjustment of the present materials model for sand to include the potential effect of moisture on inter‐particle friction can yield a significantly improved agreement between the computed and the experimentally determined sand crater shapes and sizes.
Preparation of Various Aluminum Orthophosphates and Condensed Phosphates and their Catalytic Properties
Authors: Onoda Hiroaki , Kohno Masakazu , Tamaki Jun , Kojima Kazuo , Nariai Hiroyuki
Published: October 2006

Aluminum phosphate is useful catalyst for many reactions. There are a lot of reports about catalytic activities of aluminum phosphate, however little reports about the relationship among the preparation, composition, catalytic activity of this phosphate. Phosphates transform to various other phosphates with hydrolysis and dehydration reactions by heating. In this work, some aluminum orthophosphates and condensed phosphates were prepared, and their compositions were estimated. Furthermore, specific surface area, acid strength, the amount of acidic sites, and the catalytic activities for the decomposition of trifluoromethane of these salts were investigated. Aluminum ortho‐ and polyphosphates were prepared in the systems of ortho‐ and poly‐phosphates. The catalytic activity for decomposition of CHF3 was related with a certain degree of specific surface area, acid strength, and the amount of acidic sites. Aluminum orthophosphate with a small amount of sodium cation had higher catalytic activity at lower temperature.
Study on Relationship Between Cr/C and Properties of FE‐C‐CR High Chromium White Irons
Authors: Zhiping Sun , Baoluo Shen , Jun Wang , Haohuai Liu , Hongshan Yang
Published: October 2006

The relationship between Cr/C and properties of Fe‐C‐Cr high chromium white irons was studied by calculating the valence electron structure of austenite of Fe‐C‐Cr high chromium white irons with the empirical electron theory of solids and molecules (EET) and the equilibrium phase diagram of Fe‐C‐Cr system. Results show that the C‐Cr bond is the strongest bond of all bonds in alloying austenite in Fe‐C‐Cr high chromium white irons of industrial application and, thereby, causes partial aggregation of C‐Cr atomic groups. The weight of partial aggregation of C‐Cr atomic groups would be increased greatly and more austenite would be reserved to room temperature when Cr/>6. The Fe‐CCr high chromium white irons achieve best mechanical property when Cr/C=5.5‐6.5.
Design of a Turbine Blade with Multidisciplinary Design Optimization (MDO) Method
Authors: Hua Qing , He‐fu Jiang , Wei‐dong Wen , Chang‐bo Wu
Published: October 2006

In this paper, a turbine blade was optimized by multidisciplinary design optimization (MDO) method. This turbine blade optimization is based on the optimization frame software iSIGHT, in which four disciplines (aerodynamics, thermal dynamics, structural mechanics and structural dynamics) have been integrated. Two commercial discipline analysis soft wares, NUMECA and ANSYS, are coupled in the platform iSIGHT. The three dimensional (3‐D) model of a blade was firstly parameterized. And then a set of parameters are chosen to optimize the blade to obtain the better overall properties. The result shows that the overall performances of the turbine blade have been improved remarkably after it is optimized by using the MDO method.
Electrical Properties of Posistor Composite Materials Based on Polyethylene‐Graphite
Authors: Degtyar’ov A.V. , Tonkoshkur A.S. , Lyashkov A.Yu.
Published: October 2006

In this article the electric properties of conducting polymeric compounds with graphite filler was studied to obtain the information of its structural distinctions. It was defined, that the temperature dependences of the electrical resistivity of the investigated composite materials, which had different content of conductive filler, had the posistor properties. Their frequency dependences of dielectric permittivity were found dispersed at low‐frequency area. This phenomenon was explained based on the availability of “built‐in” charges at the boundary region to the particles of graphite of polymeric layer. It was determined by outflow of free charge carries from graphite to localized states in the polymeric matrix. The estimated thickness of “built‐in” charge, in the context of the model of concentric system of conductive particles in dielectric matrix is about a micron.
There is no Hero Without a Dragon: A Revisionist Interpretation of The Myth of St. George and the Dragon
Authors: Maré Estelle Alma
Published: September 2006

It is the purpose of this paper to interpret the legend of St. George and the Dragon in terms of alchemical symbolism. While the victory of the Christian hero over the Dragon is traditionally interpreted as symbolic of the triumph of good over evil, it is argued that both combatants represent the four alchemical elements: air, water, earth and fire. Instead of a duel of opposites their combat transmutes the coiled-up energy of the dragon into solar light, which manifests as the beautiful princess of the myth. The conclusion is drawn that there is a dialectical movement of force in the battle between St. George and the dragon. The hero releases the antithetical power of the dense, dark matter symbolised by the dragon so that the elements of a polarity do not remain contrasted but are resolved creatively.
'I am Christiaan Jordan, a White Man': Liberal Anxieties and the Politics of Transition in Sheila Fugard's The Castaways
Authors: Titlestad Michael , Kissack Michael
Published: September 2006

This article assesses the contribution that Sheila Fugard's short novel, The Castaways, makes towards an understanding of the dilemmas of white identity in South Africa during the apogee of white hegemony in the mid 1970s. The novel's protagonist, Christiaan Jordan, is emblematic of a white liberal individual, who acknowledges his/her complicity in the historical violence that has been inflicted on the defeated and colonised indigenous subjects of white rule. Such individuals sought a transition to a more just future, but dreaded the violence that might attend such a transformation. We examine Jordan's embrace of Buddhism as an attempt to evade the logic of violent confrontation, demonstrating the profound difficulties involved in the translation of Buddhist philosophy into political practice. We conclude with an affirmation of the value of secular liberal democracy for the minimization of violent political conflict, despite the imperfections and compromises that this perspective implies.
The Unbearable Lightness of Being, or: Problematising the Ethical
Authors: Payne Michael
Published: September 2006

The problem of time has captivated the attention of philosophers, theologians and poets for centuries. In the following article the author addresses the issue of time using the novel The Unbearable Lightness of Being by Milan Kundera as the lens through which to view humanity's experience of time and the variety of options available for making sense out of time. The central argument of the article is explore how nihilism as portrayed through the two central characters of Kundera's novel, Tomas and Tereza, provides a unique dilemma for making sense of one's life as a whole. In explicating this aporia the article reflects on the work of Augustine, Karl Barth and Oliver O'Donovan as well as taking a fresh look at the work of Nietzsche and Martin Heidegger. In addition, the poetry of T.S. Elliott is also examined as it too reflects a Christian attempt to make meaningful what otherwise appears as something destructive of meaning, namely, the cruel contingency of time itself. If time is a creation of God and is good then what are we to make of Kundera's Unbearable Lightness of Being?
God Images and Empathy Among a Group of Secondary School Pupils in South Africa
Authors: Robbins Mandy , Kerr Shirley , Francis Leslie
Published: September 2006

A sample of 258 secondary school pupils attending year 8, 9, 10, and 11 classes in South Africa completed the empathy scale of the Eysenck Junior Impulsiveness Questionnaire, a semantic differential index of God images, and the short-form Revised Junior Eysenck Personality Questionnaire. The data demonstrate a small but statistically significant correlation between positive God images and greater empathic capacity, after controlling for sex and for individual differences in personality.
El neosexismo y diferencias de género en las metas de trabajo
Authors: Lameiras Maria , Rodríguez Yolanda , Calado Maria
Published: September 2006

En este trabajo se analiza la relación entre las metas laborales y el neosexismo de una muestra de 448 estudiantes universitarios gallegos (65,2 % de mujeres y 34,1 % de hombres). Para ello se aplica la escala de Neosexismo y la escala de Objetivos de Trabajo. Los resultados muestran las divergencias a nivel de actitudes sexistas (los chicos tienen actitudes más sexistas que las chicas) y las convergencias a nivel de metas de trabajo (tanto para ellos como para ellas es muy importante compaginar trabajo con familia y el ser el mejor en el trabajo ya no es prioritario para ninguno de los dos). También aparecen unas claras diferencias entre sexos: ellas siguen dando más importancia a la necesidad de ayudar a los demás con su trabajo y a lograr el reconocimiento por un trabajo bien hecho, mientras que ellos quieren mayor flexibilidad laboral y más tiempo para ocio y viajes. En conclusión la promoción de actitudes más igualitarias entre los más jóvenes podría favorecer la convergencia entre sexos en sus motivaciones laborales y en consecuencia en sus elecciones profesionales.
Representaciones del impacto de la situación de desempleo en las prácticas familares
Authors: Afonso Rosa-Marina , Poeschl Gabrielle
Published: September 2006

Este trabajo pretende contribuir a la comprensión de los factores que explican la ausencia de cambios en las prácticas familiares tradicionales. Se presentan dos estudios. El primero examina las representaciones del empleo y desempleo. El segundo analiza el impacto que un indicador objetivo de disponibilidad y de recursos (el desempleo) provoca en las representaciones de las prácticas familiares y en el tipo de explicaciones evocadas para su justificación. Los resultados sugieren que: (a) se atribuye a los dos cónyuges una mayor participación en las tareas familiares y una menor participación en las decisiones familiares en la situación de desempleo; (b) los hombres recurren, más que las mujeres, a justificaciones relacionadas con las diferencias entre los sexos y con los papeles tradicionales de género para explicar el desempeño de los cónyuges desempleados; (c) la participación del cónyuge masculino desempleado es, sobretodo, explicada por razones de justicia y de satisfacción, que se relacionan con el bienestar de la familia y el bienestar personal; y la participación del cónyuge femenino desempleado es justificada por motivos de tiempo libre.
Empatía y conducta prosocial durante la adolescencia
Authors: Sánchez-Queija Inmaculada , Oliva Alfredo , Parra Águeda
Published: September 2006

Aunque la relación entre empatía y prosocialidad viene siendo estudiada desde hace años prevalece aún una importante indefinición conceptual e incluso de resultados. Este trabajo pretende aportar algo de luz a la relación entre ambos conceptos y otras variables del contexto social en una muestra de adolescentes. Un total de 513 adolescentes, 221 chicos y 292 chicas de edades comprendidas entre los 13 y los 19 años cumplimentaron un cuestionario que incluía medidas sobre empatía, conducta prosocial, y aspectos relacionados con las variables familiares y de relación con los iguales. Entre los resultados obtenidos podemos destacar la relación existente entre conducta prosocial y empatía disposicional, y entre estas dos variables y las relaciones con la familia y con el grupo de los iguales. Así mismo, y en concordancia con abundante literatura científica, hallamos mayores niveles de prosocialidad y empatía en las chicas que en los chicos.
Identidad e identidad étnica en el marco de los conflictos políticos: algunas reflexiones
Authors: Pérez-Sales Pau
Published: September 2006

Se plantean algunas reflexiones respecto al tema de la identidad en el marco de situaciones de conflicto a partir de varios ejemplos paradigmáticos (jóvenes desaparecidos y reencontrados en situaciones de guerra, procesos de enculturación forzada en sociedades originarias, o procesos de transformación persistente de la identidad tras situaciones extremas de violencia). Se plantean las identidades desde un modelo de construcción social de la realidad, como estructuras identificatorias dinámicas y múltiples. Desde ésta óptica se analiza la existencia de identidades en conflicto frente a identidades del conflicto, y la frecuente existencia de falsos dilemas por la consideración, con frecuencia impuesta por la dinámica del conflicto, de estas múltiples identidades como enfrentadas e incompatibles. Las personas y las comunidades (con o sin conflicto) ofrecen una realidad mucho más polisémica. Las identidades en general, y las identidades étnicas en particular, no se constituyen así como causantes de conflicto, sino como las primeras víctimas del mismo.
Ease of retrieval as a source of information in social change judgments
Authors: Arias Ana V. , Iglesias-Parro Sergio , Morales J. Francisco
Published: September 2006

Several authors have proposed two alternative sources of information in memory based judgments: the contents retrieved from memory and the ease with which the retrieval process is perceived. Schwarz and colleagues have made it clear that, in certain circumstances, people base their judgments on the subjective experience of ease with which the information is retrieved. The present work studies the extent to which the use of this heuristic could be generalized to judgments of social change (Study 1) and some of the factors that can affect the ability to diagnose the ease of retrieval as a source of information (Study 2). The results obtained confirm the ability to generalize this heuristic to judgments of social change and to establish some conditions that affect the diagnostic- city of this source of information.
El afecto producido por la comparación social y su influencia sobre el burnout
Authors: de la Fe Rodríguez María , Osca Amparo , Peiró José M.
Published: September 2006

El objetivo del presente trabajo es estudiar la relación entre el afecto producido por el uso de la comparación social y el burnout. Para ello se ha contado con una muestra de 357 soldados profesionales de las Fuerzas Armadas Españolas. Se ha utilizado la versión española de la escala de “Identificación y Contraste” de van der Zee, Buunk, Sanderman, Botke y van der Bergh (2000). Esta escala consta de cuatro dimensiones que evalúan el afecto positivo y negativo ante la comparación social ascendente y descendente. También se usa el MBI (Maslach Burnout Inventory; Schaufeli, Leiter, Maslach y Jackson, 1996).

Se han realizado diferentes ecuaciones de regresión jerárquica para probar la influencia de las cuatro dimensiones del afecto producido por comparación social, del conflicto y la ambigüedad de rol y sus interacciones sobre el burnout. Los resultados muestran, que los afectos tanto positivos como negativos que surgen de la comparación social ascendente predicen el cinismo y el agotamiento emocional, mientras que, en la predicción de la reducción de la eficacia profesional, resultan significativas las cuatro dimensiones del afecto. También se encuentran interacciones significativas, entre las dimensiones de la comparación social y la claridad de rol, en la predicción de las tres dimensiones de burnout.
¿Puede la valencia estimular alterar la asociación entre conceptos en el IAT?
Authors: Ortiz Mercedes , Ruiz Marcos
Published: September 2006

El Implicit Association Test (IAT; Greenwald, McGhee y Schwartz, 1998) es una técnica que pretende medir fuerza asociativa entre conceptos. Sin embargo, la valencia estimular utilizada puede alterar la magnitud o incluso el sentido de esta fuerza asociativa. En este trabajo, tras un balance de las aportaciones previas, se realizó un experimento con la Intensidad Actitudinal y la Valencia Estimular como variables, obteniéndose evidencia empírica de la influencia progresiva de la valencia independientemente de la fuerza asociativa entre conceptos. De esta manera, y sorprendentemente, se consigue una mayor preferencia por el exogrupo antes que por el endogrupo.
Stratosphere–Troposphere Coupling during Spring Onset
Authors: Black Robert X. , McDaniel Brent A. , Robinson Walter A.
Published: October 2006

The authors perform an observational study of the relation between stratospheric final warmings (SFWs) and the boreal extratropical circulation. SFW events are found to provide a strong organizing influence upon the large-scale circulation of the stratosphere and troposphere during the period of spring onset. In contrast to the climatological seasonal cycle, SFW events noticeably sharpen the annual weakening of high-latitude circumpolar westerlies in both the stratosphere and troposphere. A coherent pattern of significant westerly (easterly) zonal wind anomalies is observed to extend from the stratosphere to the earth’s surface at high latitudes prior to (after) SFW events, coinciding with the polar vortex breakdown. This evolution is associated with a bidirectional dynamical coupling of the stratosphere–troposphere system in which tropospheric low-frequency waves induce annular stratospheric circulation anomalies, which in turn, are followed by annular tropospheric circulation anomalies.

The regional tropospheric manifestation of SFW events consists of a North Atlantic Oscillation (NAO)-like phase transition in the near-surface geopotential height field, with height rises over polar latitudes and height falls over the northeast North Atlantic. This lower-tropospheric change pattern is distinct from the climatological seasonal cycle, which closely follows seasonal trends in thermal forcing at the lower boundary. Although broadly similar, the tropospheric anomaly patterns identified in the study do not precisely correspond to the canonical northern annular mode (NAM) and NAO patterns as the primary anomaly centers are retracted northward toward the pole. The results here imply that (i) high-latitude climate may be particularly sensitive to long-term trends in the annual cycle of the stratospheric polar vortex and (ii) improvements in the understanding and simulation of SFW events may benefit medium-range forecasts of spring onset in the extratropics.
Consolidation of Reactive Ultem®Powder-coated Carbon Fiber Tow for Space Structure Composites by Resistive Heating
Authors: Naskar Amit K. , Edie Dan D.
Published: October 2006

In this exploratory study, polyacrylonitrile (PAN)-based carbon fiber tows are coated with a commercial, heat-crosslinkable polyetherimide (Ultem®) powder. Then an electrical current is applied across the powder-coated fiber tows (towpreg) to melt the thermoplastic powder and form rigidized composites. These consolidated composite samples are characterized by scanning electron microscopy (SEM) and conventional tensile testing. Measuring the applied current and the degree of consolidation yielded the power requirement for successful wetting of the carbon fiber tows by Ultem melt, both on earth and in outer space. The results show that resistive heating is a feasible route for the rigidization of inflatable composite structures in space.
Utopia, Nostalgia and World War at the 1939-40 New York World’s Fair
Authors: Duranti Marco
Published: October 2006

This article explores the shift from the utopian theme of the 1939 New York World's Fair to the nostalgic theme of the 1940 New York World's Fair. It argues that both seasons offered narratives intended to neutralize the disturbing implications of world war in Europe. The World of Tomorrow theme, conceived in the mid-1930s, represented an attempt to reconstitute a national narrative of progress shattered by a traumatic past experience (the Great War), an unstable present (the Great Depression), and uncertain expectations for the future (the spectre of ascendant totalitarian ideologies and another world war). The abandonment of the World of Tomorrow in 1940 suggests the failure of this attempt to resurrect a coherent narrative of progress in the face of renewed violence in Europe.

Studies of the New York World's Fair have overlooked how the outbreak of war across the Atlantic fragmented the fairgoers' experience, challenging the promise of wholeness, continuity and coherence offered by both utopian trajectories and nostalgic returns. When the 1939 season opened, Fair officials contrasted a fractious Europe with a harmonious USA, the former representing the dark aspects of modernity, while the latter embodied modernity's promise. Fair-planners had intended the World of Tomorrow to be firmly anchored in the lessons of the past and the potential of the present. As the war broke out and entire nations disappeared off the map of Europe, however, the Fair's theme appeared increasingly a halcyon dreamworld disconnected from the realities of the bloody conflict abroad.

With the effects of war echoing in the empty spaces of the pavilions of 'orphan nations', silences and nostalgic motifs disrupted the original forward-looking theme of the Fair's planners. Towards the end of the Fair's first season, with the war unsettling the utopian premise of the World of Tomorrow, the exposition's organizers increasingly invoked nostalgic themes related to a harmonious pre-industrial past. As the organizers embraced ethnic folk traditions, the particularism characteristic of nostalgia replaced universalist assumptions of progress during the exposition's second season. Similarly, the 1940 Fair organizers rejected the universalistic blurring of ideological distinctions between democratic and totalitarian systems promoted during the first season. The spectre of war cast a growing shadow across the fairgrounds and in the consciousness of fair-goers. War-related discontinuities and anxieties allowed the more troubling aspects of modernity to emerge from the Fair's imaginative cocoon.
Charles de Gaulle, Jacques Rueff and French International Monetary Policy under Bretton Woods
Authors: Chivvis Christopher S.
Published: October 2006

This article examines conservative French economist Jacques Rueff's arguments for a return to the gold standard in the 1960s. It explains the intellectual background out of which his belief in the importance of 'real money' arose, assesses his influence on the international monetary policy pursued by President de Gaulle in the mid-1960s, and sketches the relationship of his views to broader French and international debates about the international monetary system in this period. Rueff's belief in the gold standard arose in large part from his belief in the importance of monetary stability to what he considered 'Western' civilization and its struggle against the totalitarian 'East'. De Gaulle saw gold as a means of avoiding excessive supranationalism in international economic arrangements. Their plans for a return to gold were defeated for more complex reasons than are traditionally given.
Synthesis and Characteristics of MAH-g-EPDM Compatibilized EPDM/NBR Rubber Blends
Authors: Botros S. H. , Tawfic M. L.
Published: October 2006

Maleated ethylene-propylene diene monomer rubber (MAH-g-EPDM) was prepared on a two-roll mill and tested as a compatibilizer for EPDM/NBR (butadiene-acrylonitrile rubber) blend. Intrinsic viscosity measurements and scanning electron microscopy revealed that MAH-g-EPDM improved the compatibility and morphology of EPDM/NBR blend. The uncompatibilized blend showed a negative deviation in the mechanical properties after aging, from the straight line of the additive rule. However, the compatibilized blend showed a positive deviation. Also, MAH-g-EPDM improved the co-curing of EPDM and NBR rubbers. The effect of blend ratio on the heat resistance and upon the stability against UV of the elastomer blend is discussed in terms of the mechanical properties.
Graft Copolymerization of Methyl Methacrylate on to Natural Rubber: Effect of Polymerization Conditions on Particle Morphology
Authors: George Benny , Maiti S. N. , Varma I. K.
Published: October 2006

This article describes the graft copolymerization of methyl methacrylate (MMA) on to natural rubber (NR) by emulsion polymerization using cumene hydroperoxide and tetraethylene pentamine as redox initiators in NR latex. The effect of surfactants, cross-link density of NR, NR/MMA ratio, and mode of addition of monomer on particle morphology is investigated by a transmission electron microscope (TEM). The percent grafting increases with the increasing MMA content while the grafting efficiency decreases. Secondary nucleation of poly(methyl methacrylate) (PMMA) is observed when oleic acid is used as a surfactant, while sodium dioctyl sulphosuccinate (SDSS) and nonionic nonyl phenol poly(ethylene oxide), give core-shell morphology. In all the samples, the smaller rubber particles are heavily coated with PMMA while the larger particles are coated only at higher MMA content. At a given feed rate of the monomer, higher cross-link density of NR results in a more uniform shell. Ultramicrotomed sections of the latex particles show an interpenetrating network-like structure.
A Novel Akermanite Bioceramic: Preparation and Characteristics
Authors: Wu Chengtie , Chang Jiang
Published: October 2006

Akermanite (Ca2MgSi2O7) ceramics are prepared by sintering akermanite powder compacts at 1370 C for 6 h. The sintering behavior and mechanical properties of akermanite ceramics are investigated. The bioactivity of akermanite ceramics is evaluated by soaking in simulated body fluid (SBF), and hydroxyapatite (HAp) formation on the surface of akermanite ceramics after soaking is characterized by X-ray diffraction (XRD), energy dispersive spectrometry (EDS), and scanning electron microscopy (SEM). The results show that the bending strength of akermanite ceramics can reach 176 MPa, the fracture toughness is 1.83 MPa m1/2, and akermanite ceramics can induce HAp formation on their surface when soaked in SBF. Our results indicate that akermanite ceramics are bioactive, and possess improved mechanical properties compared with those of HAp ceramics and may be used as bioactive implant materials.
Determination of Crystallinity and Crystal Structure of Hylamer™ Polyethylene after in vivo Wear
Authors: Visentin M. , Stea S. , De Clerico M. , Reggiani M. , Fagnano C. , Squarzoni S. , Toni A.
Published: October 2006

Hylamer™ polyethylene is a crystalline form of polyethylene of 70% crystallinity whereas conventional polyethylene (PE) has 50% crystallinity. Crystallinity is the percentage by weight of the crystalline phase present in the whole polymer, which comprises both amorphous and crystalline phases.

Clinical experience has shown that Hylamer™ components used in joint prostheses, if sterilized by gamma rays in the presence of oxygen, are easily affected by wear, which leads to osteolysis. The authors have analyzed the crystallinity of polyethylene liners removed from seven patients who had received Hylamer™ polyethylene implants sterilized by gamma rays in air and had suffered prosthetic loosening, using Raman spectroscopy coupled with partial least squares (PLS) analysis. The results have been compared to those of two controls who had received Hylamer™ polyethylene implants sterilized by gamma irradiation in a nitrogen atmosphere. The crystal structure of wear particles released into the tissues from the Hylamer™ liners sterilized by gamma rays in air is also studied. The materials undergoing two different types of sterilization methods show different crystallinity values (71.50 vs. 69.43), but the crystallinity do not change according to wear (worn and unworn liner region). Both monoclinic and orthorhombic phases are present in the liner, while in wear debris prevalently monoclinic crystals are found in both types of sterilized liners. Different crystallinity rates can explain different wear rates observed in vivo.
Dynamics of Subcutaneous Tissue Response to the Implantation of Tetracycline-Treated or Untreated Membrane of Demineralized Bovine Cortical Bone in Rats
Authors: de Oliveira Rodrigo Cardoso , Carneiro Everdan , Cestari Tânia Mary , Taga Rumio , Granjeiro José Mauro
Published: October 2006

This study aims to conduct a histological evaluation of tissue response to a membrane obtained from demineralized bovine cortical bone, associated or not, to tetracycline (TTC). TTC treated and untreated bovine membranes were implanted in the subcutaneous tissue of rats ( n = 120). The animals were killed 1, 3, 7, 15, 30, and 60 days after surgery. The tissue around the material was fixed in 10% buffered formalin for 24 h. Sections of 6 mm were stained with hematoxylin and eosin. In general, moderate to intense inflammatory response was observed in the initial periods (1 and 3 days), moderate response in the 7- and 15-day periods, and that was remarkably reduced at 30 and 60 days. Resorptions of the membranes by mononuclear cells (fibroblasts and macrophages) and multinucleated giant cells were observed 15 days after implantation. Only the remnants of the material could be detected in some animals in 60 days. Both membranes were tolerated by the tissue and were completely resorbed after 30-60 days. While the association of TTC apparently accelerated the biodegradability of the membrane substrate, no significant differences were found in the tissue response behavior between the two groups tested.
Fuzzy Control Method for Earthquake Mitigation Structures with Magnetorheological Dampers
Authors: Xu Zhao-Dong , Guo Ying-Qing
Published: October 2006

Magnetorheological (MR) damper has a potential use in the vibration control of large structures due to its lower energy input and fine earthquake mitigation ability. A key problem for controlling structure with MR dampers is choosing the control current quickly and accurately. In order to solve this problem, a new method by using fuzzy controller, namely fuzzy full-state control method, is proposed. Dynamic responses under different inputs of fuzzy controller are compared. At the same time, dynamic responses of the traditional bi-state (BS) controlled structure and the passive full-current (PFC) controlled structure under different earthquake waves are compared with those of fuzzy full-state controlled structure. Through a numerical example about a three-story reinforced concrete structure, it can be concluded that fuzzy control technique can realize choosing of currents of MR dampers quickly and accurately and have good control effect.
The Coupled Dynamic Behavior of Piezoelectric Sensors Bonded to Elastic Media
Authors: Wang X. D. , Huang G. L.
Published: October 2006

Surface-bonded piezoelectric sensors can be used to monitor the mechanical behavior of structures for damage detection. This article provides a comprehensive theoretical study of the dynamic coupling between a surface piezoelectric sensor and an elastic half-plane. Attention is focused on the transformation of mechanical deformation into electric signals under dynamic loads. The effect of the longitudinal stiffness of the sensor is included in the developed sensor model. The problem is then formulated by using Fourier transform and solving the resulting integral equations in terms of the interfacial stress. The accuracy of the developed sensor model is evaluated by comparing with results from the finite element analysis. Numerical simulation is conducted to study the relation between the sensor response and the deformation of the host medium under static and dynamic loads. The results indicate the significant effects of the geometry of the sensor, the material mismatch of the system, and the loading frequency upon the sensor response.
Sensitive Skin and the Relative Sensing System for Real-time Surface Monitoring of Crack in Civil Infrastructure
Authors: Zhang Benniu , Zhou Zhixiang , Zhang Kaihong , Yan Guo , Xu Zhouzhou
Published: October 2006

It is difficult for the existing point monitoring methods to find the initial crack on the civil infrastructure. In this article, by adopting the area monitoring method, the sensitive skin and the relative sensing system is proposed, which has the ability to real-time monitor the initial crack on the surface of civil infrastructure. The system is composed of three main parts: sensitive skin, secondary processor, and terminal processor. The concrete specimen experiments show that the system can monitor the structural surface crack with the width down to 0.02 mm and reflect the shape and length of the crack effectively. Because the whole circuit is digital and the most consumed sensitive skin is inexpensive, the system may have excellent performance in cost, accuracy, and sensitivity.
Performance Characterization of In-plane Electro-thermally Driven Linear Microactuators
Authors: Lai Yongjun , Bordatchev Evgueni V. , Nikumb Suwas K. , Hsu Wensyang
Published: October 2006

Static and dynamic electro-mechanical performance of a microactuator is a key factor in the functioning of an integrated microsystem composed of moving components such as optical shutters/switches, micropumps, microgrippers, and microvalves. Therefore, the development of such systems primarily focuses on the overall design and parameter optimization of an actuator as the major driving element with respect to the desired performance parameters, e.g., displacement, force, dimensional constraints, material, actuation principle, and method of fabrication. This study presents results on the static and dynamic electro-mechanical performance analysis of an in-plane electro-thermally driven linear microactuator. Each microactuator, having a width of 2220 mm and made of 25 mm thick nickel foil, consisted of a pair of cascaded structures. Connecting several actuation units in a series formed each cascaded structure. Several microactuators with a different number of actuation units were fabricated using the laser micromachining technology. The static performance of these microactuators was evaluated with respect to the maximum linear output displacements, actual resistance, applied current, and consumed electric power. The maximum displacements varied approximately from 3 to 44 mm, respectively, depending on the number of actuation units. The dynamic performance was studied as a response function on constant applied current with respect to the output displacements. In addition, the response time was evaluated for different applied currents and for actuators with 2, 4, and 6 actuation units. The microactuators’ performance results are promising for applications in MEMS/MOEMS, microfluidic, and microrobotic devices.
Orientation Dependence of Nonlinearity and Hysteresis in PZN-4.5%PT Single Crystals II: Bipolar Electromechanical Response
Authors: Liu Tieqi , Lynch Christopher S.
Published: October 2006

Relaxor ferroelectric single crystals exhibit orientation dependent hysteresis. In this study, combined bipolar electric field and compressive stress are applied to relaxor single crystals of [Pb(Zn1/3Nb2/3)O3]0.955-[PbTiO3]0.045 (PZN-4.5%PT) in a series of crystal orientations between h001i and h111i. The resulting bipolar electromechanical response is presented. The observed hysteresis and nonlinear phenomena related to polarization reorientation and phase transitions are discussed.
A Finite Strain Plastic-damage Model for High Velocity Impacts using Combined Viscosity and Gradient Localization Limiters: Part II - Numerical Aspects and Simulations
Authors: Voyiadjis George Z. , Abu Al-Rub Rashid K.
Published: October 2006

In this companion article, we present within the finite element context the numerical algorithms for the integration of the thermodynamically consistent formulation of geometrically nonlinear gradient-enhanced viscoinelasticity derived in the first part of the article. The proposed unified integration algorithms are extensions of the classical rate-independent return mapping algorithms to the rate-dependent problems. An operator split structure is used consisting of a trial state followed by the return map by imposing the generalized viscoplastic and visco-damage consistency conditions simultaneously. Furthermore, a trivially incrementally objective integration scheme is established for the rate constitutive relations. The proposed finite deformation scheme is based on hypoelastic stress-strain representations and the proposed elastic predictor and coupled viscoplastic-viscodamage corrector algorithm allows for the total uncoupling of geometrical and material nonlinearities. A simple and direct computational algorithm is also used for calculation of the higher-order gradients. This algorithm can be implemented in the existing finite element codes without numerous modifications as compared to the current numerical approaches for integrating gradient-dependent models. The nonlinear algebraic system of equations is solved by consistent linearization and the Newton-Raphson iteration. The proposed model is implemented in the explicit finite element code ABAQUS via the user subroutine VUMAT. Model capabilities are preliminarily illustrated for the dynamic localization of inelastic flow in adiabatic shear bands and the perforation of a 12 mm thick Weldox 460E steel plates by deformable blunt projectiles at various impact speeds. The simulated shear band results well illustrated the potential of the proposed model in dealing with the well-known mesh sensitivity problem. Consequently, the introduced implicit and explicit length-scale measures are able to predict size effects in localization failures. Moreover, good agreement is obtained between the numerical simulations and experimental results of the perforation problem.
Influence of Coating on the Thermal Fatigue Resistance of a Ni-based Superalloy
Authors: Mabru C. , Stephan N. , Chieragatti R.
Published: October 2006

In this article, the influence of a M-CrAlY polycrystalline coating on the thermal fatigue behavior of a nickel-base superalloy has been investigated. A special device using a rotating bending machine and two thermal sources has been used to perform thermomechanical tests. The two thermal sources have been set to obtain temperature variations between 750 and 1120 C in the central part of the specimens, with a frequency of 0.1 Hz. The results show a deleterious effect of the coating on the fatigue resistance. Numerical simulations have been carried out on SAMCEF to determine the thermomechanical field of the so-tested specimens. Calculated thermomechanical cycles of critical sites are associated with micro-structure evolution and damage by cracking observed on the specimens. Damage mechanisms related to the presence of the coating are discussed.
Treatment of Lupin Seed Using the Instantaneous Controlled Pressure Drop Technology to Reduce Alkaloid Content
Authors: Haddad J. , Muzquiz M. , Allaf K.
Published: October 2006

Despite their high protein content, lupin seeds are not as fully utilised as some other grain legumes. The drawback in their utilisation is mainly due to the presence of water soluble, poisonous alkaloids. In this study, an instantaneous controlled pressure drop (DIC) treatment followed by an aqueous extraction was performed on lupin seeds. Two species Lupinus albus and Lupinus mutabilis with different initial total alkaloid content of 0.025% and 5.5% (d.b.), respectively have been studied. Lupanine was the major alkaloid found in both lupin species. Experimental results proved the feasibility of using DIC treatment to reduce the alkaloid content of lupin seeds. Optimised DIC treatment combined with an adequate 2h soaking in water reduced the alkaloid content from 5.5% to 2.2% of L. mutabilis and from 0.025% to 0.0075% of L. albus.
Note: Effect of Different Cultures on Physico-chemical and Sensory Properties of Low-fat Herby Cheese
Authors: Tarakci Z. , Kucukoner E.
Published: October 2006

The effect of three commercially available traditional cultures namely yoghurt cultures ( Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus), cheese cultures ( Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris) and helveticus culture ( Lactobacillus helveticus) on the physico-chemical and sensorial characteristics of low-fat herby cheese were investigated during ripening for 90 days. Low-fat cheese and full-fat cheese without starter culture were also produced, for comparison. Results indicated that addition of the different starter cultures on low-fat cheeses had no significant (P 0.05) effect in compositional (moisture, fat in matter, titratable acidity and pH) and biochemical (water-soluble nitrogen (WSN)), trichloroacetic acid-soluble nitrogen (TCA-SN) and phosphotungstic acid-soluble nitrogen (PTA-SN) compounds in comparison with the low-fat control cheese. The low-fat cheeses made with the starter cultures had slightly greater scores for appearance and colour, body-texture, flavour and acceptability than the control low-fat cheese after 30, 60 and 90 days ripening but differences were not significant (P 0.05). Full-fat cheeses had greater sensory scores than low-fat cheeses.
Teaching style and learning in a quantitative classroom
Authors: Giles Jan , Ryan Daniel A. J. , Belliveau George , De Freitas Elizabeth , Casey Ryan
Published: October 2006

Education research over the last few decades has focused on the debate over which classroom pedagogies best encourage learning: teacher-centred or student-centred. Although research appears to support the philosophy that student-centred teaching provides for better learning, the supporting research is frequently limited to observational studies or limited in experimental design. Despite this, the trend has been to encourage teachers to adopt a more student-centred approach both in the teaching of the course material and as a model for future teachers. A pilot study was conducted in an introductory university statistics course using a Latin Square Design to experimentally collect both quantitative and qualitative data pertaining to student performance. The purpose of this study was to examine the impact of teaching style on learning, assess these approaches in quantitative courses, and establish protocols for such studies using a statistically controlled design.
The locus of power in UK universities
Authors: Lomas Laurie
Published: October 2006

This article identifies the increasing demands on United Kingdom universities brought about by the expanded government agenda and the entry of higher numbers of more diverse students. It analyses the changes in organizational structures and cultures and identifies a centralizing tendency in terms of power to meet these demands. There is a focus on directors of educational development centres to explore how they have responded to the challenge of implementing their universities’ teaching and learning strategies in a changing and uncertain environment. There is an examination of how they identify the locus of power, their priorities, the leadership skills they employ and the coalitions they build.