bluuebunny/crossref_metadata_2025 huggingface dataset:
Wheelset skid in railway bogies
Authors: Handoko Y , Dhanasekar M
Published: July 2007

Skid of wheelsets leads to uncontrolled severe dynamics of bogies including derailment potential and damage to the running surfaces of the wheel and railhead. Simulation of wheelset skid would enhance the understanding of the skid mechanism and improve the level of safety. To effectively simulate bogie skid, the wheelsets should be modelled incorporating pitch degree of freedom. Such a model, based on a fixed inertial frame reference system, has been recently developed by the first author and is used in this paper to examine the skid of a simplified bogie containing two wheelsets and a bogie frame connected through spring-damper system. The current model accepts braking/traction torque as a primary input and calculates the longitudinal speed profile, acceleration, and distance travelled as a natural process. The calculated results have been validated using VAMPIRE where possible. The ability of the current model in predicting lateral dynamics while subjected to longitudinal skid is demonstrated through numerical examples - a feature that could not readily be predicted by most commercial wagon dynamics packages.
Microstructural evolution in sintered ice particles containing NaCl observed by low-temperature scanning electron microscope
Authors: Blackford J R , Jeffree C E , Noake D F J , Marmo B A
Published: July 2007

Ice particles containing NaCl were made by spraying 0.043 M salt solution into liquid nitrogen. The ice particles were packed into capsules and annealed at -8 °C for 168 h and -25 °C for 20 h. This material can be considered as a model material for sintered snow containing impurities. The capsules were fractured open inside the low-temperature scanning electron microscope, which minimized the artefacts caused by cryofixation. The morphology of the sintered structure was observed with low-temperature scanning electron microscope. The microstructure of the sintered material consists of ice grains with a liquid meniscus containing NaCl between the grains. This structure is similar to the equilibrium morphology of water-filled veins in polycrystalline ice and liquid phase sintered metallic materials. The combined effect of the surface energies between the solid, liquid, and vapour governs the morphology of the microstructure. A dihedral angle where the brine intersects a grain boundary in ice of 8.0 ± 2.6°, and a contact angle for brine on ice at the interface with vapour of 5.0 ± 1.3° were measured, for samples quenched from -8 °C. Using the dihedral angle measurement, a surface energy value for ice-brine of 32.6 ± 0.1 mJ/m2 was calculated.
Advanced thermal spray coatings for tribological applications
Authors: Bartuli C , Valente T , Casadei F , Tului M
Published: July 2007

Thermal spray coating is one of the most common procedures to improve the tribological properties of materials. Ceramic and cermet coatings, especially those based on oxides (alumina, chromium oxide, etc.) and carbides, are widely used for wear protection. Improvements under investigations are related to the possible use of nanostructured coatings and to the potential application of hybrid techniques. As a possible alternative, solid lubrication is proposed as integration or replacement of the traditional liquid lubrication in the case of severe operative conditions when there is the possibility of a lack of lubricant or when environmental problems can arise from waste disposal. In the present paper, results from experimental activities on different types of abrasion-resistant thermal spray coatings are presented: graded coating systems, specifically designed for titanium-based alloys, obtained by reactive plasma spraying and physical vapour deposition of titanium nitrides; nanostructured WC-Co coatings deposited by high velocity oxy-fuel; plasma-sprayed ceramic coatings based on oxides containing nanophases either from nanostructured precursors or postprecipitated by purposely designed thermal treatments; self-lubricant coatings deposited by plasma spray with the inclusion of graphite.
Mechanical behaviour and superplastic forming capabilities of extra-low interstitial grade Ti-6Al-4V wire alloy with numerical verification
Authors: Naughton M D , Tiernan P
Published: July 2007

In this paper, the behaviour of extra-low interstitial (ELI) grade Ti-6Al-4V wire alloy has been extensively studied at varying strain rates in the range of 10-5-102 s-1 at temperatures ranging between 750 °C and 1050 °C using processing maps and experimental data to determine the material's mechanical and superplastic forming capabilities. From the slope of a log plot of strain rate versus flow stress, the strain-rate sensitivity index, m, was determined. A plot of m versus the log of strain rate was produced in order to identify the key strain rates in which ELI grade Ti-6Al-4V exhibits its superplastic regime. It was determined that this alloy is most sensitive to superplastic forming within a narrow strain-rate band of 10-4-10-3 s-1 and has a maximum strain-rate sensitivity index, m = 0.45. At strain rates below and above this range, the material exhibited negligible levels of superplasticity. The key temperature for superplastic forming was determined to be 950 °C. The effect of temperature on flow stress and flow stability was analysed using the Zener-Holloman parameter. The experimentally determined results showed excellent agreement with Guo and Ridley's activation mathematical model.
A Green Chemical Synthesis of 2-Alkylbenzimidazoles from 1,2-Phenylenediamine and Propylene Glycol, or Alcohols Mediated by Ag–TiO2/Clay Composite Photocatalyst
Authors: Selvam K , Swaminathan M
Published: July 2007

Benzimidazole derivatives were synthesized in good yield from 1,2-phenylenediamine (PD) and various alcohols by photocatalytic cyclization with TiO2/acidic clay composite catalyst using UV–A and solar light. Doping silver on TiO2 enhances product yield and selectivity of the photocatalytic synthesis of benzimidazoles. The higher efficiency of nano-Ag-doped TiO2 in solar light makes this synthesis a green chemical process.
A Novel Process to Prepare Magnetic Polymer Microspheres
Authors: Yang Jian , Bi CaiXia , Su ZhiGuo , Ma GuangHui
Published: July 2007

A new process for preparation of magnetic microspheres was investigated. In this process, the formation and the encapsulation of magnetic nanoparticles were accomplished in one step. The magnetic polymer microspheres exhibited superparamagnetic property and had a spherical shape with a smooth surface. This method can be used to prepare inorganic and organic composite particle when the inorganic particles can be prepared by chemical coprecipitation reaction.
Removal of Toxic Pollutants from Aqueous Solutions by Adsorption onto an Organobentonite
Authors: Jacobo-Azuara Araceli , Leyva-Ramos Roberto , Padilla-Ortega Erika , Aragón-Piña Antonio , Guerrero-Coronado Rosa Maria , Mendoza-Barron Jovita
Published: July 2007

An organobentonite was prepared by adsorbing the cationic surfactant hexadecyltrimethylammonium bromide (HDTMA) onto the surface of a calcium bentonite. The adsorption capacity of the organobentonite towards 2,4-dichlorophenoxyacetic acid (2,4-D), phenol and the dichromate ion (HCrO−4) from aqueous solutions was investigated. The Langmuir isotherm gave a reasonable fit to the experimental data for the sorption of 2,4-D, phenol and the HCrO−4 ion onto the organobentonite. The adsorption equilibrium data for 2,4-D demonstrated bimodal adsorption for equilibrium concentrations of 2,4-D greater than 650 mg/l. The capacity of the organobentonite for sorbing 2,4-D, phenol and the HCrO−4 ion was considerably higher than that of the bentonite. This capacity was compared to that of a commercial activated carbon (F-400), from which it was concluded that modification of the bentonite substantially enhanced its adsorption capacity whereas the capacity of the organobentonite was lower than that of the F-400 carbon.
Physicochemical Properties of the Co3O4/Al2O3, Ag2O/Al2O3 and Ag2O-Co3O4/Al2O3 Systems and Their Catalytic Activities towards Acid-Base and Redox Reactions
Authors: El-Sharkawy E.A. , Al-Shihry Shar S. , Youssef A.M.
Published: July 2007

A Co3O4/Al2O3 catalyst containing 0.20 mol% Co3O4 and an Ag2O/Al2O3 catalyst containing 0.2 mol% Ag2O were prepared using the impregnation method. Co3O4–Ag2O/Al2O3 samples containing 0.2 mol% Co3O4 and varying small molar percentages of Ag2O were also prepared. Portions from the catalysts thus obtained were calcined at 773, 973 and 1173 K.

The textural properties of the catalysts were determined from the adsorption of N2 at 77 K, while their structural properties were investigated using TG, DTA, XRD and TPR techniques. The surface acidities of the catalysts were determined via titration with n-butylamine in a non-aqueous medium. The conversion of propan-2-ol at 573 K was followed using the micro-catalytic pulse technique, whereas the decomposition of H2O2 at 298–313 K was followed by determining the volume of oxygen released with time.

Solid-solid interactions between the components of the systems resulted in the formation of Co3O4 and CoAl2O4, their ratio depending on the chemical composition and heat-treatment temperature employed with Ag in its metallic form. The textural properties of the investigated catalysts also depended on the chemical composition and calcination temperature. The surface acidity of the catalysts is an important factor in determining their catalytic activity towards the conversion of propan-2-ol whereas the redox-reactive ion-pairs formed between Ag and Co determine their activity towards H2O2 decomposition.
Globalization of Food Retailing and Transformation of Supply Networks: Consequences for Small-scale Agricultural Producers in Southeastern Mexico
Authors: Biles James J. (James John) , Brehm Kevin , Enrico Amanda , Kiendl Cheray , Morgan Emily , Teachout Alexandra , Vasquez Katie
Published: July 2007

The previous decade has witnessed an unprecedented expansion and consolidation of supermarket chains on a global scale. Notwithstanding a wealth of recent research on the global expansion of multinational food retailers, the existing literature largely overlooks the transformation of supply networks and resulting impacts on firms, workers and regions in host countries, where international supermarket chains procure the vast majority of food products for local markets. In addition, the bulk of previous research has been carried out in developed nations, ignoring one of the most striking trends of the past decade – the rapid and unfettered expansion of international retailers in developing countries, especially Asia and Latin America. This paper provides an assessment of the impacts of the globalization of retailing on supply-network linkages between food retailers, intermediaries and small-scale agricultural producers in Yucatán, Mexico. In the context of a global production networks (GPN) framework, this case study reveals that the transformation of supply networks, and concomitant implications for small-scale producers, is mediated by locally contingent relationships among national and international food retailers, intermediaries, state government officials, and agricultural and livestock producers, as well as global economic processes. Durante la última década hemos sido testigos a la expansión y consolidación de cadenas de supermercados a una escala global. No obstante los numerosos estudios recientes enfocados en la expansión global de las tiendas de autoservicio, ha pasado casi desapercibido la transformación de las redes de distribución y las consecuencias para las empresas, trabajadores, y regiones en países receptores, donde los supermercados multinacionales surten la gran mayoría de sus productos para los mercados locales. Además, se ha realizado la gran mayoría de los trabajos de investigación anteriores en países desarrollados, sin tomar en cuenta una de las tendencias más sobresalientes de la última década – la proliferación desbordada de las cadenas multinacionales en países en vías de desarrollo, especialmente Asia y América Latina. En este trabajo se analizan los impactos de la globalización entre las tiendas de autoservicio, los intermediarios y los pequeños productores agropecuarios en Yucatán, México. En el contexto del marco conceptual GPN (redes de producción globales), este estudio de caso revela que la transformación de las redes de producción, y las consecuencias para los pequeños productores, surge tanto de las relaciones locales entre las cadenas de autoservicio, los intermediarios, funcionarios del gobierno estatal, y los productores mismos, como de los procesos económicos globales.
Mexican Smallholders Adrift: The Urgent Need for a New Social Contract in Rural Mexico
Authors: Gravel Nathalie
Published: July 2007

In the new Mexican rural economy, unfavorable market conditions for agricultural products and the lack of support to small-scale productive activities act as incentives to cease operations and leave for the city, or even the U.S. Why is it becoming increasingly difficult for smallholders to live off agricultural production in Mexico? In attempting to answer this question, the impacts of NAFTA and trade liberalization on the capacity of small Mexican producers to market their crops cannot be ignored. Nevertheless, the opening up of the Mexican economy since 1982 is not solely to blame for the hardships they experience. Mexican rural socio-economic marginalization will be explored as it relates to a differentiated access to productive resources. Results of an inquiry in the state of Querétaro, central Mexico, provide insight into the asset portfolios of rural households and the life options and economic strategies of their members. Among these strategies are a growing agricultural disintensification and a diversification of rural household economic activities, including a new dependence on migration remittances. En la nueva economía rural mexicana, las condiciones de mercado desfavorables tal como la falta de apoyo a las actividades productivas de pequeña escala en el campo son motivaciones para los minifundistas para emprender migraciones hacia la ciudad o los EE.UU. ¿Porque se está volviendo cada vez más difícil vivir de la pequeña producción agrícola en México? No se pueden ignorar los impactos negativos del Tratado de Libre Comercio de América del Norte (TLCAN) (1994) sobre la capacidad de los pequeños productores para comercializar sus cosechas. Sin embargo, la apertura de la economía mexicana a partir de 1982 no es la única responsable de las privaciones experimentadas por muchos de los minifundistas. La estructura de la marginalización socioeconómica rural mexicana será analizada en cuanto a su vínculo con el acceso a los recursos productivos agrícolas. Los resultados de una encuesta en el estado de Querétaro, en el centro de México, presentan carpetas de recursos de los hogares rurales e opciones de vida como estrategias económicas de sus integrantes. Dentro de esas estrategias se encuentran la desintensificación agrícola y una creciente diversificación de las actividades económicas, incluyendo una nueva dependencia sobre las remesas.
Globalization of Food Retailing in Guadalajara, Mexico: Changes in Access Equity and Social Engagement
Authors: Harner John
Published: July 2007

Globalization and neoliberal reforms affect the form and spatial distribution of commercial food retailing in Guadalajara since the early 1990s. I examine the equity of access to commercial food vendors for the urban poor and discuss the changing social relations that come about with increased economic rationalization. Equity is evaluated by calculating indices that compare access to public markets versus supermarkets for both the poor and non-poor populations. The index is calculated for both 1990 and 2000 to measure change across the decade. Equally important are the socio-cultural changes that come with new food consumption behaviors. This paper suggests that Mexico should not forsake traditional retail food outlets for globalized forms of retailing, but should seek a better articulation between the two. La globalización y las reformas neoliberales afectan la forma y la distribución territorial del comercio al detal en Guadalajara desde principios de los años noventa. En esta investigación examino la equidad de acceso de la población pobre a los vendedores de alimentos, y las relaciones sociales cambiantes que surgen con el incremento de la racionalización económica. Se calcula la equidad con índices que comparan el acceso a los mercados públicos y a los supermercados para las poblaciones pobres y no-pobres. El índice calculado abarca el periodo 1990 y 2000 y se utiliza para medir los cambios entre las dos fechas. También son de singular importancia los cambios socio-culturales que vienen acompañados de una nueva actitud de consumo. Este ensayo sugiere que México no debe abandonar los mercados tradicionales por opciones extranjeras de globalización, sino buscar una mejor articulación entre ambos tipos de comercio.
Persistence of the U. S.-Mexico Border: Expansion of Medical-Tourism amid Trade Liberalization
Authors: Judkins Gabriel
Published: July 2007

Recent free-trade rhetoric asserts that political and economic trade liberalization agreements diminish the effect of international borders and result in widespread land-use and land-cover change. Some suggest that this trend portends the minimization of distance and geography as factors influencing change in human-environment relations. This research questions these assertions through an examination of the burgeoning border trade in medical-tourism. Trade based on medical-tourism is defined primarily by a persistence of the border as an economic and social barrier, allowing the juxtaposition of difference in geographic proximity. The rapid growth of medical-tourism along the U.S.-Mexico border indicates that in spite of decades of free-trade agreements including NAFTA, the border remains intact with regard to the medical services industry. The function, reach and urban land-use changes related to this trade are explored through a case study approach of Los Algodones, Mexico. Ciertas discusiones recientes sobre libre comercio argumentan que la liberalización política y económica disminuye el efecto de las fronteras internacionales y provoca grandes cambios tanto en uso como en cobertura de suelo. Algunos investigadores sugieren que esta tendencia presagia la reducción de la distancia y la geografía como factores que influencian el cambio en las relaciones ser humano-ambiente.  La presente investigación cuestiona tales enunciados mediante un análisis del creciente comercio trans-fronterizo asociado con el turismo de servicios médicos.  La actividad comercial generada por el turismo de servicios médicos se define principalmente por la existencia de la frontera como barrera social y económica, permitiendo la yuxtaposición de la diferencia en la proximidad geográfica. El rápido crecimiento del turismo de servicios médicos en la frontera México-Estados Unidos indica que, sin importar décadas de tratados de libre comercio entre los que figura el TLCAN, la frontera permanece intacta en lo que respecta a la industria de servicios médicos.  La función, alcance y cambios en uso de suelo urbano relacionados con este comercio son explorados a través de un caso de estudio en Los Algodones, Baja California, México.
Economic Globalization and Bolivia's Regional Divide
Authors: Schroeder Kathleen
Published: July 2007

Bolivia provides an example of the immense complexity of local responses to globalization. This paper emphasizes the regional differences that influence how Bolivians react to economic globalization and in particular to the terms of sale of natural gas. Some highland indigenous communities contest aspects of the neo-liberal global economy while many in the lowland mestizo class embrace opportunities that come from participation in the global economy. The election of Evo Morales in 2006 has brought many of these differences to the forefront because he has vowed to favor domestic consumption of natural gas over export and take seriously the state's responsibilities to the poor. El caso de Bolivia sirve como muestra de la inmensa complejidad que existe en las respuestas locales a la globalización. Este trabajo se enfoca en las diferencias regionales que influyen en la reacción de los bolivianos a la globalización económica, especialmente con respecto a las condiciones para la venta del gas natural. Algunas comunidades indígenas de las tierras altas disputan ciertas características de la economía global neoliberal, mientras que muchos grupos de las tierras bajas, donde predomina la clase mestiza, están a favor de las oportunidades que surgen de la participación en la economía global. La elección de Evo Morales en 2006 hace resaltar muchas de estas diferencias debido a su decisión de cumplir con las responsabilidades del estado hacía los pobres y su compromiso de promover el consumo doméstico, y no la exportación, del gas natural.
Beyond the Crisis: Economic globalization and informal work in urban Argentina
Authors: Whitson Risa
Published: July 2007

During the economic crisis in Argentina that peaked in 2002, rates of informal work rose to levels higher than those at any other time during the previous 60 years. Drawing on interviews with informal workers conducted in 2002, I address the connection of this informal work not only to the crisis conditions in the country at the time, but also to broader shifts in the nature of work in Argentina. In particular, I argue that a lack of availability of formal work, an increase in probationary employment, and an increase in contractual arrangements were all crucial components of the dependence on informal work seen during the crisis of 2002. Making sense of the experience of contemporary informal work in Argentina thus requires an acknowledgement of history of globalization of the Argentine economy, which was brought about in large part through the implementation of neoliberal policies that began in the 1980s and continue today. Durante la crisis económica en Argentina en el año 2002, la tasa de participación en el trabajo informal creció hasta el punto más alto que en los últimos 60 años. Usando datos de entrevistas realizadas en el 2002, en este artículo analizo la relación entre este trabajo informal y tanto las condiciones de crisis en el país durante este tiempo, como los cambios más amplios en el carácter del trabajo en Argentina. En particular, sostengo que la falta de disponibilidad del trabajo formal, un aumento en los contratos de prueba, y un aumento en la contratación de trabajadores independientes, fueron todos componentes críticos de la dependencia del trabajo informal durante la crisis del 2002. Para entender las experiencias actuales del trabajo informal en Argentina, se necesita un reconocimiento de la historia de la globalización de la economía argentina, que fue facilitado por la implementación de las políticas neoliberales que empezó en los 80 y que continúa hoy en día.
(Re-)Staging Love's Labour's Lost
Authors: Carroll William C.
Published: July 2007

Michael Kahn, director of the Love's Labour's Lost for the Shakespeare Theatre Company (Washington, D.C.) in 2006, was invited by the Royal Shakespeare Company to bring his production to Stratford-upon-Avon as part of its program staging all of Shakespeare's plays. Kahn set the play in India in the 1960s, alluding to the Beatles' visit to the Maharishi Mahesh Yogi, and invoked several other markers of that time period. The production was a considerable commercial success, both in England and the U.S., and was generally praised for its originality and energy. What no reviewer noticed, however, was that Kahn had offered exactly the same production in 1968 at the American Shakespeare Theatre in 1968. All the publicity for the 2006 production, as well as Kahn's own comments on the company's website, implied or stated that this was a new production. This essay reviews the details of Kahn's production and attendant publicity and the theoretical issues raised by its concealed repetition, and then considers other productions of the play in the 1960-80 period, from China to Bulgaria, that depict the play in more political terms.
Locating the Bard: Adaptation and Authority in Michael Radford's The Merchant of Venice
Authors: Pittman L. Monique
Published: July 2007

This article analyzes Michael Radford's The Merchant of Venice (2004) starring Al Pacino and Jeremy Irons. Engaging with W.B. Worthen's approach to Shakespearean performance studies, the article is concerned with the ways in which Radford utilises a return to period setting and costuming - after roughly a decade of radicalized adaptative strategies - in order to legitimize his film, particularly from the perspective of its treatment of race. The study is primarily concerned with the way in which this emphasis on historical accuracy marks an attempt on Radford's part to articulate connections that harmonize cultural differences and point to human commonality that transcends time periods, while also striving to absolve Shakespeare of the racism and ethnic prejudices that underpinned the culture in which he was writing. Through focusing on specific moments and characters (the film's context-laden opening sequence, the sympathetic and dangerously unproblematic portrayals of Shylock and Portia), the essay illuminates Radford's attempts to offer viewers a sanitized and "correct" version of Shakespeare's play, demonstrating how he thus misses out on the far richer possibilities of a text that dramatizes prejudice in a range of registers and that in its unsettling ambiguity problematizes the very notions of absolute authority that the film chases with such vigor. Ultimately, the essay seeks to demonstrate how through an emphasis on authorial intention and a simultaneous ignorance of the complexity of the source text, Radford's film appropriates Shakespeare too insistently for an uncomplicated vision of religious and ethnic tolerance.
The Forgotten Hamlet
Authors: Terris Olwen
Published: July 2007

The article examines critical reception to the television adaptation by Peter Brook of his staging of Hamlet with Paul Scofield in the title role. Transmitted on 27 February 1956 by Associated Television (ATV), this was the first broadcast of a Shakespeare play franchised by the Independent Television Authority, the newly formed and first UK commercial television company. The article also considers the impact of television advertising during the transmission of the play and comments on the friction between culture and commercialism in the very early days of television broadcasting.
Numerical Analysis of Rectangular Plate with Symmetric Edge Cracks and Edge Half-Circular Hole Cracks in Tension
Authors: Yan Xiangqiao
Published: July 2007

This paper is concerned with the stress intensity factors (SIFs) of a rectangular plate with symmetric edge cracks and edge half-circular-hole cracks in tension (see Figs. 1 and 2) by using the displacement discontinuity method with crack-tip elements (a boundary element method) proposed recently by the author. It is found that the boundary element method is simple, yet accurate for calculating the SIFs of complex crack problems not only in infinite plate [1] but also in finite plate [2]. Specifically, detail solutions of the SIFs of the two plane elastic crack problems are given, which can reveal the effect of H/W on the SIFs. By comparing the calculated SIFs of the symmetric edge half-circular-hole cracks (Fig. 2) with those of the symmetric edge cracks (Fig. 1); in addition, a shielding effect of the half-circular hole on the SIFs of the symmetric edge half-circular-hole cracks are discussed in detail.
Methodology for Evaluating Candidate Geometric Reference Scaffolds
Authors: Dunkers Joy P. , Leigh Stefan D. , Dean David , Cooke Malcolm N. , Ketcham Richard A. , Cicerone Marcus T.
Published: July 2007

Along with the ASTM Division IV subcommittee on Tissue Engineered Medical Products, the National Institute of Standards and Technology is developing a geometric reference scaffold. This paper describes the methodology applied to the three different types of candidate reference scaffolds to quantify their structure and rank them according to quality metrics. In this work, we detail this methodology using the candidate reference scaffold produced by stereolithography. We perform X-ray micro-computed tomography on three of the manufactured scaffolds and compute total porosity, pore size distribution, and pore length for each. We compare these quantities to those of the model scaffold using statistical measures of variational distance, relative uncertainty, and uniformity. Through this evaluation, we find that the scaffold produced by stereolithography agrees well with its model and merits further consideration as a reference scaffold.
Measurement of Strain Distribution and Material Flow in Bulk Deformation by the Screw Method
Authors: Zhang J. , Yuan S. J. , He Z. B.
Published: July 2007

A new method for the observation of material flow and measurement of plastic strain in deformed parts is proposed. First, a specimen with machined threaded holes containing threaded bolts was deformed and then sectioned along the mid-section of the bolts. The deformed screw interfaces at the section were observed and measured by a microscope. The plastic strain on the screw interfaces was calculated by the change of screw pitch. The experimental results and numerical simulation show good agreement. In contrast to other physical modeling methods, this method utilizes the actual metal for sensor and workpiece, rather than using substitute materials. Furthermore, the proposed method can be used to observe and measure material flow and plastic strain inside the specimen without splitting it before deformation. It can be used to study material flow and predict strain distribution in general bulk metal forming processes such as upsetting, extrusion, die forging, etc.
On a class of extremal solutions of the nondegenerate matricial Carathéodory problem
Authors: Fritzsche Bernd , Kirstein Bernd , Lasarow Andreas
Published: July 2007

The main theme of this paper is a thorough study of a parametrized family (Ω
Improved Grazing Management Increases Terrestrial Invertebrate Inputs that Feed Trout in Wyoming Rangeland Streams
Authors: Saunders W. Carl , Fausch Kurt D.
Published: July 2007

Research in forest and grassland ecosystems worldwide indicates that terrestrial invertebrates can be a significant source of prey for fish, providing about 50% of their annual energy. We examined whether input of terrestrial invertebrates to rangeland streams in western Wyoming provides an important prey resource for brown trout Salmo trutta and brook trout Salvelinus fontinalis and how it is modified by livestock grazing. During summers of 2004 and 2005 we sampled falling invertebrate input and trout diets in five pairs of streams that had riparian zones under two different grazing systems: High‐density, short‐duration (HDSD) grazing versus season‐long (SL) grazing. The biomass of riparian vegetation and the input of terrestrial invertebrates were two to three times greater in reaches with riparian zones under HDSD than under SL grazing management. Likewise, the afternoon diets of individual trout in HDSD reaches had, on average, about twice as much terrestrial invertebrate biomass during summer than those of trout in SL reaches, but this was statistically significant only during late summer due to high variability. Overall, 57% of the afternoon diets of trout in reaches under both grazing systems consisted of terrestrial prey. Diel diet sampling during August 2005 showed that fish in HDSD reaches also had consumed more aquatic invertebrate prey, primarily at night. Total trout biomass in HDSD reaches was more than twice that in SL reaches. These results suggest that in rangeland streams of the western United States, both terrestrial and aquatic invertebrates are important prey resources for trout and that improved grazing management has the potential to influence fish populations through multiple food web pathways.
Briefing: Web-conferencing boosts participation in ICE events
Authors: Armstrong Richard
Published: July 2007

Last year, ICE started using a state-of-the-art web-conferencing system to enhance communications with members and to increase the accessibility of its learned society events. Technical support manager Richard Armstrong provides an update.
A clearer vision for pedestrian guardrails
Authors: Stewart Douglas
Published: July 2007

Pedestrian guardrails have been used increasingly on Britain's streets since the 1930s, but their value is now being questioned by planners in the light of the new trend of reducing street furniture. This paper disputes claims that guardrail removal enhances safety by presenting evidence of the large reductions in casualties after erection of guardrails, particularly those that do not block visibility. Chronic lack of research is highlighted, with particular reference to visibility and its inadequate treatment in design standards. Deterrence of diagonal crossing is identified as a prime reason why guardrails are so successful in preventing pedestrian accidents, which clarifies how they can be used most effectively. Recent work to improve the design of guardrails is also outlined.
A triaxial investigation of kinematic yielding in sand
Authors: Kuwano R. , Jardine R. J.
Published: July 2007

The elastic-plastic behaviour of a reconstituted sand is considered under triaxial conditions, covering a wide range of strains. Monotonic probing tests are used to identify two types of kinematic yield surface for samples with loose and dense initial states, under drained and undrained conditions and after different patterns of consolidation. Plastic strain development and global stiffness degradation are found to be closely interrelated, and the interpretation involves decoupling the elastic and plastic strain components. The sizes and the shapes of the loci are strongly affected by effective stress states and histories, including any periods allowed for creep and ageing. A tentative qualitative micromechanical explanation is offered for the phenomena observed.
Static equilibrium bays in coast protection
Authors: Herrington S. P. , Li B. , Brooks S.
Published: July 2007

As part of the 2004 Hythe to Folkestone Harbour coast protection scheme, two static equilibrium bays were formed using rock headland structures and shingle imported as part of the beach renourishment phase of the scheme. The development of this element of the scheme and the appraisal process that led to these bay forms being chosen as the most appropriate form of coast protection are discussed. The performance of the bays has been continually monitored since their construction and the measured plan-shape of each bay has been compared with the theoretical predictions. This has shown that there is good agreement between the crenular planforms predicted by the mathematical models and the theoretical methods, which are founded on the log-spiral curve that has been shown to represent the crenular planform of naturally formed bays. Observations based on the survey data collected over the 20 months since the completion of the scheme have shown that the measured planform is in relatively good agreement with the theoretical predictions. The bays do, however, exhibit distinct yet small differences from the theoretical form, but nevertheless are approaching an equilibrium state
Planning supply transport in port works
Authors: Moura Berodia J. L. , dell'Olio L. , Portilla A. Ibeas
Published: July 2007

Normally public works carried out on ports have a huge impact on the surrounding area due to the transportation of large quantities of raw material. The impact is even greater if the works are carried out in an urban area resulting in serious traffic congestion as well as pollution, dust and noise. This paper proposes a model for the management of such works and is applied to a case study based on the new port at Laredo (Spain). The model optimises the distribution of loads between lorries and barges with the aim of minimising the total economic, social and environmental costs. The total cost of the system was calculated from the costs used in operating the lorries and barges as well as from a social cost represented by the costs to private transport users caused by the increased congestion due to the activity of lorries on the road network. All of this is limited by environmental restrictions aimed at keeping the emissions of both private and works vehicles within the established pollution and noise standards. Finally, a series of interesting conclusions are presented for the correct planning of the transport system that was analysed.
Analysing eyewitness reports of the 2004 Asian tsunami
Authors: Spence R. , Palmer J. , Petal M. , Kelman I. , Saito K.
Published: July 2007

On 26 December 2004, one of the largest earthquakes of the last 100 years occurred off the Indonesian coast, causing ground shaking over a wide region, and triggering a massive and destructive tsunami, which devastated the coasts bordering the Indian Ocean causing huge loss of life. Many parts of this coastline are popular holiday destinations and a large number of European tourists were in the region at the time, and as many as 4000 of these tourists may have been UK citizens. To find out more about the experiences of these tsunami eyewitnesses, supplementing data on the event assembled by reconnaissance teams, a study was carried out to locate and interview eyewitnesses. During the course of the research some 87 eyewitness accounts were obtained, and these have been assembled into a database from which some preliminary analysis has been made. This paper contains a summary of the project. It describes the methods used, gives extracts from the eyewitness accounts, provides some cross-regional analysis of the database and discusses the findings and their significance.
Comparison of velocity measurements by high temperature anemometer and laser-doppler anemometer with results of CFD-simulation
Authors: Zimmel M. , Rath J. , Staudinger G. , Simpson B. , Brown M. , Balmer J.
Published: July 2007

In the present work, results of gas velocity measurements with a newly developed vane anemometer (HTA - High Tem per a ture Anemometer) are compared with re sults of measurements obtained from Laser-Doppler Anemometer (LDA). The measurements were carried out at the combustion test rig of ALSTOM Combustion Services Ltd. in Derby/UK, and demonstrate the usability and accuracy of the HTA under severe conditions. The test rig was provided with a triple register low NOx coal burner firing pulverised Colombian blended coal at a constant thermal load of 30 MW. Although the environment was both very hot (up to 1350 ?C) and dust laden, the vane anemometer worked with an accuracy comparable to the reference LDA measurement. Since the anemometer represents a relatively simple to use and low cost option compared with LDA, it is seen as aviable alternative for gas velocity measurements in difficult environments. The measurement results are also demonstrated to compare favourably with the results from CFD calculations of the flow in the combustion chamber of the test rig.
In-situ laser spectroscopy of CO, Ch4, and H2O in a particle laden laboratory-scale fluidized bed combustor
Authors: Lackner Maximilian , Totschnig Gerhard , Loeffler Gerhard , Hofbauer Hermann , Winter Franz
Published: July 2007

The pyrolysis, devolatilization and char combustion of bituminous coal and biomass (beechwood, firwood) were investigated in a laboratory-scale fluidized bed combustor by tunable diode laser spectroscopy. Individual fuel particles were suspended in the freeboard of the unit. The bed temperature was 800 ?C, the oxygen partial pressure 0 to 20 kPa (0-10 vol.%). Two Fabry Perot type tunable near infrared diode lasers were deployed for quantitative in-situ species concentration measurements. CH4 and CO were measured simultaneously during devolatilization and char combustion in-situ 10 mm above the surface of the fuel particles as well as H2O using laser spectroscopy. Sand particles were passing the probing laser beam path. Besides the resonant absorption of the laser light by CO, CH4 and H2O severe and strongly transient non-resonant attenuation by partial blocking of the beam and beam steering effects occurred. By wavelength tuning the two laser sources, species concentrations could be determined. The measured absorbances had to be corrected for the real temperature measured at the position of the probing laser beam. In addition, CO, CO2 and O2 were determined ex-situ by con ventional methods. A spatial profile inside the FBC of major species (CH4, CO, CO2, O, H, OH) was calculated using a chemical kinetics program for a single fuel particle in a plug flow reactor geometry. The results were compared to the experimental findings. Good agreement was found. Tunable diode laser spectroscopy was found to be an apt method of determining quantitative species concentrations of multiple gases in a high temperature multi phase environment.
Agglomeration of bed material: Influence on efficiency of biofuel fluidized bed boiler
Authors: Ryabov Georgy , Litoun Dmitry , Dik Eduard
Published: July 2007

The successful design and operation of a fluidized bed combustor requires the ability to control and mitigate ash-related problems. The main ash-related problem of biomass filing boiler is agglomeration. The fluidized bed boiler with steam capacity of 66 t/h (4 MPa, 440 ?C) was started up at the Arkhangelsk Paper-Pi dp-Plant in 2001. This boiler was manufactured by the Russian companies "Energosofin" and "Belenergomash" and installed instead of the existing boiler with mechanical grate. Some constructional elements and steam drum of existing boiler remained unchanged. The primary air fan was installed past the common air fan, which supply part of the air into 24 secondary airports. First operating period shows that the bed material is expanded and then operator should increase the primary air rate, and the boiler efficiency dramatically decreases. Tills paper presents some results of our investigations of fuel, bed and fly ash chemical compositions and other characteristics. Special experiments were carried out to optimize the bed drain flow rate. The influence of secondly air supply improvement on mixing with the main flow and boiler efficiency are given.
Quasi-equilibrium channel model of an constant current arc
Authors: Gerasimov Alexander , Kirpichnikov Alexander
Published: July 2007

The rather simple method of calculation of electronic and gas temperature in the channel of arc of plasma generator is offered. This method is based on self-consistent two-temperature channel model of an electric arc. The method proposed enables to obtain radial allocation of gas and electronic temperatures in a non-conducting zone of an constant current arc, for prescribed parameters of discharge (current intensity and power of the discharge), with enough good precision. The results obtained can be used in model and engineering calculations to estimate gas and electronic temperatures in the channel of an arc plasma generator.
FBC utilization prospects in decentralized cogeneration units in Caucasus region countries
Authors: Skodras George , Amarantos Panayiotis , Kakaras Emmanuel
Published: July 2007

Great differences are encountered among Caucasus region countries with respect to energy resources reserves and economic conditions. Thermal power plants consist of obsolete and inefficient units, while the Soviet-type large heating systems in the area collapsed after 1992 and their reconstruction is considered uneconomic. Renovation needs of the power and heat sector, and the potential of Fluidised Bed Combustion implementations in decentralized cogeneration units were investigated, since operating oil and gas power plants exhibit high fuel consumption, low efficiency and poor environmental performance. Results showed significant prospects of Fluidised Bed Combustion utilization in decentralized cogeneration units in the Caucausus region heat and power sector. Their introduction constitutes an economically attractive way to cover power and heat demands and promotes utilization of domestic energy resources in all of three countries, provided that financial difficulties could be confronted.
Fluidized bed combustion with the use of Greek solid fuels
Authors: Kakaras Emmanuel , Grammelis Panagiotis , Skodras George , Vourliotis Panagiotis
Published: July 2007

The paper is an overview of the results obtained up to date from the combustion and co-combustion activities with Greek brown coal in different installations, both in semi-industrial and laboratory scale. Combustion tests with Greek lignite were realized in three different Circulating Fluidized Bed Combustion (CFBC) facilities. Low rank lignite was burned in a pilot scale facility of approx. 100kW thermal capacity, located in Athens (NTUA) and a semi-industrial scale of 1.2 MW thermal capacity, located at RWE's power station Niederaussem in Germany. Co-combustion tests with Greek xylitic lignite and waste wood were carried out in the 1 MWth CFBC installation of AE&E, in Austria. Lab-scale co-combustion tests of Greek pre-dried lignite with biomass were accomplished in a bubbling fluidized bed in order to investigate ash melting problems. The obtained results of all aforementioned activities showed that fluidized bed is the appropriate combustion technology to efficiently exploit the low quality Greek brown coal either alone or in conjunction with biomass species.
On the evolution of laminar to turbulent transition and breakdown to turbulence
Authors: Jovanovic Jovan , Pashtrapanska Mira
Published: July 2007

Starting from the basic conservation laws of fluid flow, we investigated transition and breakdown to turbulence of a laminar flat plate boundary layer exposed to small, statistically stationary, two-component, three-dimensional disturbances. The derived equations for the statistical properties of the disturbances are closed using the two-point correlation technique and invariant theory. By considering the equilibrium solutions of the modeled equations, the transition criterion is formulated in terms of a Reynolds number based on the intensity and the length scale of the disturbances. The deduced transition criterion determines conditions that guarantee maintenance of the local equilibrium between the production and the viscous dissipation of the disturbances and therefore the laminar flow regime in the flat plate boundary layer. The experimental and numerical databases for fully developed turbulent channel and pipe flows at different Reynolds numbers were utilized to demonstrate the validity of the derived transition criterion for the estimation of the onset of turbulence in wall-bounded flows.
The main natural lows of high-rate coal pyrolysis
Authors: Chemyavsky Nikola
Published: July 2007

The importance of coal pyrolysis studies for the development of energy technologies is evident, since pvrolysis is the first stage of any process of coal thermal conversion. In combustion, pyrolysis determines conditions of coal ignition and the rate of char after-burning, in gasification, pyrolysis determines total yield of gasification products. It must be noted that in modern energy technologies pyrolysis occurs at high late of coal particle heating (=10 K/s for different fluidized bed, or FB-technologies) or super-high-rate (>10**5 K/s for entrained-flow gasification), and in some of them at high pressure. In CETI during last 12 years the detailed study of pyrolysis in FB laboratory-scale PYROLYSIS-D plant and entramed-flow pilot-scale GSP-01 plant, was carried out. In this paper main results of mentioned investigations are given. Kinetic constants for bituminous coals and anthracite high heating rates in entrained flow for high temperatures (>1500 ?C and >1900 ?C), and in fluidized bed conditions in temperature range 972-1273 K. In order to describe data obtained in fluidized bed conditions, G--model based method of calculation of devolatization dynamics was suited to FB heating conditions. Calculated and experimental kinetic data are in good agreement. The result proves that at FB-pvrolysis conditions intrinsic mass-transfer limitations are negligible and devolatilization is really kinetic-controlled.