bluuebunny/crossref_metadata_2025 huggingface dataset:
Automatic Recognition of Fabric Nature by Using the Approach of Texture Analysis
Authors: Kuo Chung-Feng Jeffrey , Tsai Cheng-Chih
Published: May 2006

This paper proposes an approach to texture analysis that could be used to recognize the fabric nature and type of the main weaving texture. First, the color scanner captures the fabric image and saves it as a digital image and then the wavelet transformation is used to display the image texture. The co-occurrence matrix is then be applied to calculate the texture characteristics, such as angular second moment, entropy, homogeneity, and contrast, and finally, the learning vector quantization networks (LVQN) are adopted as a classifier to categorize the fabric nature and the type of weaving texture. The experimental result showed that this approach could automatically and accurately classify the fabric nature, including woven fabric, knitted fabric and non-woven fabric, and the type of its main weaving texture, such as plain, twill or satin weave, single or double knitted and non-woven fabric.
Cognitive-Behavioral Therapy for Comorbid Generalized Anxiety Disorder and Panic Disorder With Agoraphobia
Authors: Labrecque Joane , Dugas Michel J. , Marchand André , Letarte Andrée
Published: May 2006

The goal of this study was to evaluate the efficacy of a cognitive-behavioral treatment package for comorbid generalized anxiety disorder (GAD) and panic disorder with agoraphobia (PDA). A single-case, multiple-baseline, across-subjects design was used with 3 primary GAD patients with secondary PDA. The efficacy of the treatment was evaluated with a structured interview, a battery of self-report questionnaires, and daily self-monitoring booklets. Results are promising: At posttreatment, 2 out of 3 participants achieved high endstate functioning and maintained this level at 3-, 6-, and 12-month follow-ups. The 3rd participant also improved but achieved moderate endstate functioning. The strengths and limitations of the treatment are discussed.
Effects of Behavior-Contingent and Fixed-Time Release Contingencies on Frequency and Duration of Therapeutic Restraint
Authors: Luiselli James K. , Pace Gary M. , Dunn Erin K.
Published: May 2006

Reducing therapeutic restraint is a desirable outcome for programs that serve individuals who exhibit challenging behaviors. This study investigated the effects of modifying the criterion for release from therapeutic restraint on frequency and duration.Release from restraint was changed from a behavior-contingent criterion (restraint terminated when a specified duration of calm behavior was demonstrated) to a fixed-time criterion (restraint terminated when a predetermined duration elapsed independent of behavior) with one child and two adolescents with acquired brain injury and difficult-to-manage behaviors. For all three students, the duration of time they were exposed to therapeuticrestraint decreased with the fixed-time release criterion,whereas the frequency of restraint did not change. Practical implications of these results and future research opportunities are discussed.
Using Food Aversion to Decrease Severe Pica by a Child With Autism
Authors: Ferreri Summer J. , Tamm Lori , Wier Kristin G.
Published: May 2006

Food aversion was shown to be effective in the reduction of plastic pica by a 4-year-old boy with autism. The participantwas sufferingfrom digestive complicationsdue to the ingestionof plastic from a variety of toys. The intervention was initially conducted in the child's preschool classroom during instructional periods and was systematically generalized to the entire preschool classroom, and eventually to both classrooms within the preschool and across 25 teachers. The success of the intervention in decreasing pica was enhanced by its achievement in not reducing interactions with toys, considering appropriate play skills were a target goal.
The Relationship of Comorbid Problem Behaviors to Social Skills in Persons With Profound Mental Retardation
Authors: Matson Johnny L. , Minshawi Noha F. , Gonzalez Melissa L. , Mayville Stephen B.
Published: May 2006

Research into behavior problems among individuals with mental retardation has been well developed. However, few studies have addressed the effect of multiple problem behaviors on social skills. In the present study, the authors examined the relationship between two problem behaviors, stereotypy and self-injury, and social skills among individuals with profound mental retardation. A total of 120 participants were divided into four groups based on the presence of stereotypic and self-injurious behavior. Persons with comorbid stereotypy and self-injury evinced more negative nonverbal social skills than did those with self-injury alone or no problem behaviors. In the past, researchers examined behavior problems as isolated phenomena. However, a recent shift in the conceptualization of problem behaviors has exposed the lack of research regarding the nature of social and adaptive skills in the face of multiple topographies of problem behaviors using broader conceptualizations.
Positive Versus Negative Perfectionism in Psychopathology
Authors: Flett Gordon L. , Hewitt Paul L.
Published: May 2006

This article reviews the concepts of positive and negative perfectionism and the dual process model of perfectionism outlined by Slade and Owens (1998). The authors acknowledge that the dual process model represents a conceptual advance in the study of perfectionism and that Slade and Owens should be commended for identifying testable hypotheses and future research directions. However, the authors take issue with the notion that there are two types of perfectionism, with one type of perfectionism representing a “normal” or “healthy” form of perfectionism. They suggest that positive perfectionism is motivated, at least in part, by an avoidance orientation and fear of failure, and recent attempts to define and conceptualize positive perfectionism may have blurred the distinction between perfectionism and conscientiousness. Research findings that question the adaptiveness of positive forms of perfectionism are highlighted, and key issues for future research are identified.
Commodity Cultures, Mesoamerica and Mexico's Changing Indigenous Economy
Authors: Cook Scott
Published: May 2006

A case is argued for the constitutive role of commodity value (use + exchange + symbolic), and its shifting triangulations, in Mesoamerican and Mexican indigenous culture. This role cross-cuts historical epochs but assumes more pervasive influence historically in proportion to the spread of integrative markets and monetization. Given their commodity value matrix, indigenous direct-producing subjects, yesterday and today, are assumed to economize, regardless of the nature and destination of their labor or products or the particular social relations organizing the latter's disposition. Particular forms of commodity value triangulation require empirical determination at specific spatial/temporal coordinates. Critical evaluations of work by Karl Marx, Guillermo Bonfil, Alejandro Marroquín, Manuel Gamio and Arturo Warman, together with ethnographic material, are used to support the case for the commodity value approach.
‘I Thought Horses Was the Best Thing Ever’
Authors: Wilson Tamar Diana
Published: May 2006

Tourism is a major source of income for the Irish economy: in 2002 there were 1.55 tourists per resident of the Republic. When high unemployment rates hit the country in the 1980s, a new niche in the tourist economy was opened in Dublin: jarveying, or taking tourists around the city by horse and carriage. Involving agency and entrepreneurship, the Dublin jarveys are of proletarian origins, coming from some of the poorest areas in the city. The fathers of many of the pioneers were carters during the petrol shortage of the Second World War and its aftermath, and sons thus had a knowledge of handling horses. They in turn trained sons and nephews and young wannabe jarveys in the trade. Conscious of their class origins, the jarveys are notable for their love of horses and their enjoyment of taking tourists on a routinized ‘walk’ around the city, while pointing out sites of historical or contemporary significance. They are entrepreneurs due to both need (labor market disadvantage) and desire, and have carved out for themselves a photogenic niche in Dublin's tourist economy.
The Kind of Writing
Authors: Doja Albert
Published: May 2006

In a now much-read critique, Derrida claimed to show the weakness and the supposed contradictions of Lévi-Strauss's interpretation of writing and his characterization of modern industrial society by the pathology of written communication. Lévi-Strauss is tweaked however for everything at odds with what is normally understood as Lévi-Straussian analysis. It is my contention in this article to argue that, by misconstruing Lévi-Strauss's actual theoretical and epistemological contribution to general knowledge, Derrida's reading of Tristes Tropiques is exemplary and influential in that it joins together all the essential didactic elements of ‘deconstructionist’ criticism, and seems to be what exactly ‘lit-crit’ deconstructionism is all about, which in the last analysis turns into an arrogant scholastics that only ignorance or deliberate misinformation could allow.
Scholarly Surrealism
Authors: Hervik Peter , Kahn Hilary E.
Published: May 2006

We imagine Mayanness as an enduring ‘pure’ substrate below surfaces of diversity that is constructed and maintained through surrealistic scholarship. Equipped with community studies, theories and methods, scholars surrealistically construct ideas of Mayanness, as do the millions of self-identified Mayan individuals from Guatemala, Mexico, Belize and beyond. We use Salvador Dalí's masterpiece, The Persistence of Memory, as a playful device for explaining how Mayanness is perpetuated in practice, within ethnographic contexts, and always in realms of power. Mayanist discourse is analogous to Surrealism in many, but not all, ways. Mayanist discourse is clearly surrealistic when we view it as emerging from discordance and paradox, but it differs from Surrealism when it masks and replaces the surreal with aesthetic, palatable and ‘pure’ images of coherence and rationality. By acknowledging our scholarly surrealism, we suggest that we may encounter a bit of academic iconoclasm and liberation. By embracing the inherent paradox, rather than concealing it, we contribute to polemical academic debates regarding constructed binary oppositions, geographic foundations of identity, alternative methodologies and means of representation, and issues of continuity and change in Mayan scholarship and lives.
Optimized Parallel Interrogation and Protection of Piezo-transducers in Electromechanical Impedance Technique
Authors: Hey Farrand , Bhalla Suresh , Soh Chee Kiong
Published: May 2006

This article presents some of the practical issues concerning the implementation of the electromechanical impedance (EMI) technique for structural health monitoring (SHM) using piezoelectric ceramic (PZT) transducers. New sensor interrogation algorithms utilizing the sensor multiplexing technique are proposed to reduce the time required in interrogating the PZT patches one-by-one for localizing damage. Environmental effects on the admittance signatures of the PZT patch are considered, and a simple and economical technique is proposed to protect the PZT patches. Finally, practical application of PZT transducers in the monitoring of concrete curing is demonstrated.
Modeling, Fabrication, and Testing of a SMA Hybrid Composite Jet Engine Chevron Concept
Authors: Turner Travis L. , Buehrle Ralph D. , Cano Roberto J. , Fleming Gary A.
Published: May 2006

This study presents a fabrication method, bench top test results, and numerical model validation for a novel adaptive jet engine chevron concept based upon embedding shape memory alloy (SMA) actuators in a composite laminate, termed a SMA hybrid composite (SMAHC). The approach for fabricating the adaptive SMAHC chevrons involves embedding prestrained Nitinol actuators on one side of the mid-plane of the composite laminate such that thermal excitation generates a thermal moment and deflects the structure. A rigorous and versatile test system for control and measurement of the chevron deflection performance is described. A recently commercialized constitutive model for SMA and SMAHC materials is used in the finite element code ABAQUS to perform nonlinear static analysis of the chevron specimens. Excellent agreement is achieved between the predicted and measured chevron deflection performance, thereby validating the numerical model and enabling detailed design of chevron prototype(s) and similar structures.
Experimental and Theoretical Behavior of Self-healing Bolted Joints
Authors: Antonios Charbel , Inman Daniel J. , Smaili Ahmad
Published: May 2006

This article focuses on improving the experimental behavior of a self-healing bolted joint using shape memory alloys (SMAs). Self-healing bolted joints are used to reduce the likelihood of failure of structures due to loosening of bolted joints. The clamping force (CF) in a bolted joint assembly plays an important role in maintaining the integrity of the structure. Controlling the preload in a bolted joint assembly by external heating activates the heat-to-recover (HTR) SMA washer. The SMA washer is initially in the martensitic state. When the bolt is loosened to a certain amount of preload, a heater enveloping the ring is activated allowing an axial constrained recovery of the SMA and a control of the preload in the bolt. Several experiments are conducted to ascertain the effect of heating rate, cooling rate, relaxation of assembly, and initial preload, on the preload-temperature relationship. Experimental results indicate that the use of SMA rings is promising for retightening and controlling preload in bolted joint assemblies. Two analytical models are established; one is based on the Liang-Rogers model (Liang, C. and Rogers, C.A. 1990. “One-dimensional Thermo-mechanical Constitutive Relations for Shape Memory Materials,” Journal of Intelligent Materials Systems and Structures, 1:207-234) and the other draws on the analogy between the cyclic stress-strain curves.
Investigations of the Nonlinear Behavior of Piezoceramic Hollow Cylinders
Authors: Laskewitz B. , Kamlah M. , Chen C.
Published: May 2006

This article deals with the investigation of the suitability of piezoceramic hollow cylinders for the exploration of electromechanical loading histories with multiaxial stress states. Analytical investigations give a first indication of a nonlinear distribution of the electric potential and, as a result, of an inhomogeneous electric field. These results motivate a deeper investigation by finite element calculations taking into account ferroelectric and ferroelastic hysteresis behavior. A phenomenological constitutive model representing these properties has been implemented into an open source finite element code and is used to simulate the poling process in the radial direction and mechanical loading in the axial direction. The results confirm inhomogeneous distributions of electric fields and stresses during and after poling. This limits the suitability of hollow cylinders for the investigation of the multiaxial electromechanical behavior of piezoceramics. A geometry variation is discussed to minimize the aforementioned effects.
A Trigonometric Recurrence Algorithm for Solving Nonlinear Problems in Structural Dynamics
Authors: Rosales Marta B. , Filipich Carlos P.
Published: May 2006

An analytical-numerical methodology for solving nonlinear problems governed by partial differential equations (PDE) is presented. The authors have previously used a method named WEM that consists essentially of the statement of extended trigonometric series of uniform convergence (UC). Theorems, demonstrated previously, ensure the UC of the essential functions and the exactness of the eigenvalues. WEM has been applied to nonlinear dynamic problems in two different ways: As a direct variational method and as a solution in the classical sense. The present tool is applied in the second fashion and starts from the statement of the extended trigonometric series for all the unknown functions and derivatives involved in the PDE. The nonlinearities are treated in the same way. The application of consistence conditions leads to recurrence relationships among the coefficients of the extended series. For the sake of comparison an initial conditions problem (the well-known Duffing oscillator) is numerically solved. Then a beam example is solved in detail: A linear (both material and geometrical) supported beam, with end springs of nonlinear analytical response, under the action of a dynamic distributed load and/or prescribed initial conditions, is studied. Two numerical examples are included.
Damping Capacity of Layered and Jointed Copper Structures
Authors: Nanda B. K.
Published: May 2006

This paper considers the mechanism of damping and its theoretical evaluation for layered copper cantilever structures jointed with a number of equispaced connecting bolts under an equal tightening torque. Extensive experiments have been conducted on a number of specimens for comparison with numerical results from the theory. Intensity of interface pressure, its distribution characteristics, dynamic slip ratio and kinematic coefficient of friction at the interfaces, relative spacing of the connecting bolts, and frequency and amplitude of excitation are all found to have an effect on the damping capacity of such structures. It is established that the damping capacity of copper structures jointed with connecting bolts can be improved considerably by increasing the number of layers while maintaining uniform intensity of pressure distribution at the interfaces.
Control of Sound Pressure in a Piston-Pipe System using Active Compression Damping Treatment
Authors: Chen T. , Chaiwanon P. , Baz A.
Published: May 2006

The sound pressure level in a one-dimensional piston-pipe enclosure is controlled using the Active Compression Damping (ACD) treatment. The ACD treatment, which is bonded directly to the driving piston, uses the compression and expansion deformations of visco-elastic material sandwiched between the electromagnet and a permanent magnet to dissipate the acoustic energy inside a piston-pipe system. ACD treatment is an active/passive hybrid controller. When the active part fails due to a malfunction of any element in the control circuits, the passive part still operates and gives acceptable control efforts.

The behavior of the system is evaluated by monitoring the sound pressure level at the closed end of the pipe with single tone, two-tone and broad band noise excitations. Proportional and Derivative feedback control are used to activate the electromagnetic actuator. The results obtained indicate significant attenuation of the acoustic energy inside the pipe.
Vibrations of Mindlin Sectorial Plates Using the Ritz Method Considering Stress Singularities
Authors: Huang C. S. , Chang M. J. , Leissa A. W.
Published: May 2006

This paper reports very accurate vibration frequencies of moderately thick sectorial plates with various boundary conditions and vertex angles (α=90°, 180°, 270°, 300°, 330°, and 355°) based on Mindlin plate theory, and provides the nodal patterns of their vibration modes for the first time in the published literature. Most of the extensive frequencies presented are exact to the four digits shown. The classical Ritz method is employed, using corner functions and algebraic trigonometric functions as the admissible functions. Because the corner functions properly describe the singularity behaviors of moments and shear forces in the vicinity of the vertex of a sectorial plate, they substantially enhance the convergence and accuracy of the numerical results, which is shown by convergence studies.
Control of Three-axis Stabilized Flexible Spacecraft Using Variable Structure Strategies Subject to Input Nonlinearities
Authors: Hu Qinglei , Ma Guangfu
Published: May 2006

This paper proposes a robust control algorithm for stabilization of a three-axis stabilized flexible spacecraft in the presence of model uncertainty, external disturbances and control input nonlinearities. This control algorithm is based on a variable structure output feedback control design technique, and explicitly accounts for the control input nonlinearities in the stability analysis. The proposed variable structure output feedback controller ensures the global reaching condition of the sliding mode of the spacecraft dynamics system. Moreover, in the sliding mode, the investigated dynamic system still retains the robustness with respect to the uncertainties and disturbances it possesses for a system with linear input. An attractive additional feature of the control method is that the structure of the controller is independent of the elastic mode dynamics of the spacecraft, since in practice the measurement of flexible modes is typically difficult or impractical. It is also shown that an adaptive version of the proposed controller can be achieved by removing the need to know the bounds of the uncertainties and perturbations in advance. Numerical simulations show that the precise attitude control and vibration suppression can be accomplished using the derived controller for both cases with and without adaptive control.
Calorimetry and Pressure-shift Freezing of Different Food Products
Authors: Zhu S. , Ramaswamy H. S. , Le Bail A.
Published: May 2006

Rapid depressurisation can create uniform, small and abundant ice nucleation during pressure-shift freezing (PSF) which can then protect the frozen food structure from cell damage. The amount of depressurisation-formed ice was evaluated using a high-pressure calorimeter for different food products (tylose, potato, salmon, pork and water). Experiments were conducted at an initial pressure of 62, 82, 112, 156, 180 and 196MPa, at temperatures set at −5, −7, −10, −15, −18 and −20°C, respectively (slightly above the phase diagram of water-ice I). Calorimetric thermograms recorded during PSF tests were used for computing the quantity of ice formed based on heat balance. A polynomial relationship was established for each product to compute the depressurisation-formed ice ratio as a function of the initial pressure applied. This model accurately predicted the maximum ice ratio for PSF at a given pressure (0.1 to 210MPa) or the minimum ice ratio for PSF at a given temperature (−22 to 0°C). Moisture content was the major factor affecting the sample-mass based (SMB) ice ratio with higher moisture yielding a higher SMB ice ratio. A general relationship between water-mass based (WMB) ice ratio ( R'ice-water) and initial pressure was found from the pooled data from all tested products: R'ice-water 0.114 P+0.00022 P2 (R2 0.94, n 47) which agreed well with relevant literature values for pure water.
Structure and Nanostructure of the Outer Tangential Epidermal Cell Wall in Vaccinium corymbosum L. (Blueberry) Fruits by Blanching, Freezing-Thawing and Ultrasound
Authors: Fava J. , Alzamora S. M. , Castro M. A.
Published: May 2006

The design of minimal technologies for blueberries preservation requires, among others, the knowledge of structural and ultrastructural cell changes during the processing. This work examined the main structural alterations that occurred in the outer tangential epidermal cell wall of fruits of Vaccinium corymbosum L. (blueberries) due to blanching, freezing-thawing and ultrasound. Light microscope (LM), environmental scanning electron microscope (ESEM), transmission electron microscope (TEM) and atomic force microscope (AFM) observations were analysed and discussed. Each treatment produced specific effects on the outer tangential epidermal cell wall of the epicarp: swelling and rupture of the inner and outer tangential cell wall by blanching; and cell wall shrinkage and rupture by ultrasound; and folding and compression of the epicarp by freezing-thawing. After treatments, a delimited transition between the cuticle, the cutinised layer and the cellulosic layer on the outer tangential epidermal cell wall was observed in all treated fruits.
Consumer Beliefs and Attitudes Towards Dry-cured Ham and Protected Designation of Origin Teruel Ham in Two Spanish Regions Differing in Product Knowledge
Authors: Cilla I. , Martínez L. , Guerrero L. , Guàrdia M. D. , Arnau J. , Altarriba J. , Roncalés P.
Published: May 2006

This work compared the responses of a consumer survey on beliefs and attitudes towards dry-cured ham and protected designation of origin (PDO) Teruel ham carried out in two Spanish regions differing in Teruel ham knowledge: Aragon (high knowledge) and Catalonia (lower knowledge). Results revealed that only small differences were found regarding dry-cured ham consumption habits. With regard to beliefs related to factors affecting ham quality, differences were even lesser; raw material and maturing process, as well as marbling, colour and flavour and proper saltiness were rated as the most important quality factors. Nevertheless, large significant differences were evident between both regions in knowledge, consumption, beliefs and attitudes towards PDO Teruel ham. However, there were no differences regarding the willingness to pay a higher price for PDO ham. Multiple correspondence analysis of all data revealed large effects of age, education, income level and size of the place of residence, independent from the region of origin of the consumer.
Evaluation of Two Quality Indices Related to Ice Storage and Sensory Analysis in Farmed Gilthead Seabream and Seabass
Authors: Tejada M. , Huidobro A. , Mohamed G. Fouad
Published: May 2006

Two farmed fish species of great importance in the European market, gilthead seabream ( Sparus aurata; GSB) and seabass ( Dicentrarchus labrax; SB) reared in different conditions were analysed to determine the best index to be used for calibration of a prototype designed for rapid measurement of freshness in ice stored fish. Sensory evaluation (quality index) was related to K-value (percent of the ratio of inosine plus hypoxanthine to adenosine-5-triphosphate (ATP) and breakdown products) and Torrymeter readings, chosen as indices that detect early changes in the ice stored fish. Higher K-values were obtained in SB than in GSB, however the degradation of ATP and derivatives followed the same pattern in the different lots in each species. No statistical differences in the evolution of K-value for the same storage time were observed, irrespective of the amount of ATP and breakdown products, muscle composition and rearing conditions of the fish. K-value correlated strongly with storage time and sensory evaluation measured in the raw fish, however, correlation of Torrymeter readings with storage time or sensory evaluation was much lower. This makes K-value a good index in these species for calibrating an apparatus designed to measure time-related changes in fish in response to chill storage.
Influence of Thermal Treatment and Soy Bean Protein Characteristics on Muscle Protein Emulsion Stability
Authors: Rodríguez M. P. , Regue C. , Bonaldo A. , Carrara C. , Santiago L. G.
Published: May 2006

The effects of heat treatment on the interaction of salt soluble muscle protein and soy protein isolate in model emulsions were studied. Three soy protein isolates (SPI) were used: a commercial one (CSPI) and two pilot plant samples: a native soy protein isolate (NSPI) and an acid treated soy protein isolate (ASPI). Emulsions were prepared with muscle protein (MP), NSPI, ASPI, CSPI and mixtures of MP and the different SPIs, and then treated at 20, 55, 70, 80 and 90°C. Coalescence, soluble protein and electrophoresis of the aqueous phase of the emulsions were evaluated for each temperature. At 20°C the more native soy protein (NSPI) was compatible with MP, producing a stable emulsion that became more stable during heat treatment. CSPI alone could not form a stable interfacial film through the temperature range, however emulsion stabilisation was achieved at 55°C and 70°C when adding MP. Emulsions prepared with MP ASPI were highly unstable at 20°C, while as the emulsion temperature increased, coalescence decreased abruptly and maintained low values at every temperature. MP, NSPI, ASPI and MP NSPI produced stable emulsions both at 20°C and higher temperatures.
Reducing Asymmetries in Intergenerational Justice
Authors: Karlsson Rasmus
Published: May 2006

Normally, contractual conceptions of intergenerational justice regard the responsibility held by each generation as symmetrical. This article argues that the late modern society has created an asymmetry because of its unprecendented instrumental and destructive capacity. Historically unique risks such as thermonuclear destruction, global ecological deprivation, and resource depletion all point at this asymmetry and unequal distribution of responsibility between generations. Extending one contractual device used by John Rawls in line with what Brian Barry has suggested, this article analyzes the roots of the asymmetry and presents two political strategies to end it. The first strategy resembles the traditional deep ecological programme whereas the second holds an imaginative vision of a human future in space. Both strategies seek to reduce the influence present generations exercise on the level of opportunity available to future generations. The key normative argument is that intergenerational justice requires spatial and temporal limits on political action.
Total Factor Productivity
Authors: Burkett Paul
Published: May 2006

Total factor productivity (TFP) is a central concept in the mainstream analysis of economic growth. Using aggregate production functions, economists estimate the shares of economic growth explained by increases in capital, labor, and (in some applications) natural resource inputs. The residual of unexplained growth is then ascribed to “disembodied” technological advance or TFP. This article develops a radical ecological-economic critique of TFP analysis. The critique uses Marxist theory to synthesize relevant nonmainstream perspectives including ecological economics (especially Georgescu-Roegen's critique of the aggregate production function and Daly's rejection of the mainstream “circular flow” vision of the economy), neo-Schumpetarian criticisms of disembodied technological change, and the “identification” critique which shows that TFP estimates merely capture the accounting identity between income and value added. From a Marxist perspective, TFP theory's false dematerialization of production technology reflects capitalism's alienation of workers and communities from necessary conditions of production.
Learning and Knowledge-building in Open-source Communities
Authors: Hemetsberger Andrea , Reinhardt Christian
Published: May 2006

Open-source communities are innovative online communities, some of which have recently attracted increasing attention. The study suggests that members of innovative online communities learn and build collective knowledge through the use of ‘technologies’ and the establishment of discursive practices that enable virtual re-experience. Theories of knowledge creation and learning have been reviewed and a social-experiential view of learning has been applied in order to examine the reflective inquiry processes and collective learning practices. The findings demonstrate that re-experience is enabled by code, transactive group memory, instructive content and discourse, and reflective discourse. The manifestations of learning processes lead to concrete experience, reflective observation, abstract conceptualization, and active experimentation at the individual level. Collective reflection, collective conceptualization, virtual experimentation, and participative practice are initiated at the social level. Empirical evidence is based on an interpretive investigation of the K Desktop Environment (KDE) community—an open-source software project that is administered online.
Human Resource Management as a Determining Factor in Organizational Learning
Authors: López Susana Pérez , Peón José Manuel Montes , Ordás Camilo José Vazquez
Published: May 2006

The role of human resource management in learning organizations has been discussed by a number of researchers. It is suggested that some of the more traditional personnel functions of HR practitioners may be tailored to encourage a focus on learning and thus to help achieve organizational goals. However, there is a lack of empirical studies that explore the relationship between human resource management and organizational learning. This article aims to address this shortcoming. More specifically, the purpose of this article is to analyse the relation between four human resources practices (hiring, training, compensation and decision-making) and organizational learning. The hypotheses proposed were tested on a sample of 195 Spanish companies using the structural equation modelling technique. The results support that selective hiring, strategic training and employee participation in decision-making positively influence organizational learning.
Recipe or performing art?
Authors: Fisher Kath , Phelps Renata
Published: May 2006

This article explores the tensions and incongruities between conventional thesis presentation and the principles of action research. Through the experiences of the authors alternative approaches to thesis structure are proposed which are argued to be more congruent with the epistemological, methodological and ethical aspects of action research. Consistent with our arguments, the article is presented as a play. Act I considers the tensions facing research students wishing to write up their action research in the context of conventional thesis writing requirements; Act II consists of four ‘scenes’, each of which illustrates a key learning arising from our own stories: writing in the researcher as central to the research; staying true to the unfolding research story; using metaphor; and finally, weaving literature throughout the thesis. Act III considers the challenges of examination in the face of breaking with tradition. We conclude with a ‘curtain call’ from the narrator that offers a reflexive engagement with the main themes of the article.
Positioning the practitioner-researcher
Authors: Ragland Betty B.
Published: May 2006

When I considered research in my practice as a supervisor of teachers working inside a juvenile correctional facility, I sought ways to explore aspects of my personal experience. Heeding Reason's (1994) call for ‘critical subjectivity’ in attending to the ground on which one stands, I suggest that it is possible, by craning my neck or standing on tiptoe, as it were, to change positions, if not to leave the ground entirely. In this article I seek to capture a moment in the process of action research – a moment that occurs before engaging with others in collaborative sense-making in our joint practice. I explore my experience in this moment through five different perspectives: subjective embodiment in the practice; reflection on the practice; frames of reference; relevant and emergent theories; and personal stakes in the matter. While this effort falls within the realm of firstperson inquiry as discussed by Reason and Marshall (2001), Torbert (2000), and Reason and Torbert (2001), it also has elements of second-person inquiry, as it is oriented toward the practice I share with others.
Critical reflection
Authors: Chiu Lai Fong
Published: May 2006

Critical reflection is commonly seen as central to social transformation in Participatory Action Research (PAR). However, the groundings and practice of the concept and its associated applications are seldom questioned or examined. The lack of a clear conceptual basis upon which reflective practice could be developed is manifested in the routinized presentations of ‘lessons learnt' in writings. This article inquires into the concept of critical reflection and its current practice in PAR, drawing on key contributors and current PAR writings. This exploration has prompted a construction of a conceptual framework grounded on the principle of extended epistemology (Heron, 1992), in which the role of reflection or critical reflection in the creation of different forms of knowledge can be clearly discerned. In addition, the framework explicitly incorporates first-, second and third-person research practice (Reason & Torbert, 1999) to allow for the different aspects of reflective practice to emerge. Examples from my own reflective practice are given to illustrate the various dimensions of the framework. I argue this framework provides a clearer conceptual basis upon which reflective practice can be developed, with important implications for the future development of PAR.
PLastic Films for Agricultural Applications
Authors: Espí E. , Salmerón A. , Fontecha A. , García Y. , Real A. I.
Published: May 2006

The most important agricultural applications of plastic films are greenhouse, walk-in tunnel and low tunnel covers, and mulching. The raw materials are usually low density polyethylene (LDPE) and ethylene-vinyl acetate (EVA) or ethylene-butyl acrylate (EBA) copolymers for the covers and linear low density polyethylene (LLDPE) for mulching. The market is explosively growing in China, and slowly growing in the rest of the world. The key properties for these applications are durability, optical (ultraviolet, visible, near infrared, and middle infrared) properties, and the antidrip or antifog effect. Recent developments in this area include UV-blocking, NIR-blocking, fluorescent, and ultrathermic films.
The Effect of Atmospheric Glow Discharge (APGD) Treatment on Polyetherimide, Polybutyleneterephthalate, and Polyamides
Authors: Ruddy A. C. , McNally G. M. , Nersisyan G. , Graham W. G. , Murphy W. R.
Published: May 2006

Polyamide 6, polyamide 12, polybutyleneterephthalate, and polyetherimide films are plasma treated in an APGD unit using various applied voltages, gas flow rates, frequencies, and dwell times. The results show changes in the surface chemistry (FTIR); the degree of change in dynamic contact angle is found to be dependent on the polymer type, dwell time, and electrical characteristics of the plasma.
The Effect of Metallocene-Catalyzed Polyethylene on the Physicomechanical Properties of Film Blends with Conventional Linear Low-Density Polyethylene
Authors: Cran Marlene J. , Bigger Stephen W.
Published: May 2006

Film blends of metallocene-catalyzed linear low-density polyethylenes (mLLDPEs) with conventional linear low-density polyethylene (LLDPE) – with both LLDPEs being made using hexene comonomer – were prepared and investigated. The addition of mLLDPE to conventional LLDPE significantly improves the dart impact strength but has little effect on the overall clarity of the resulting films. Conversely, the addition of a small amount of LLDPE to mLLDPE improves the optical properties of the latter.
Orientation,Structure and Properties of Double-Bubble Oriented Lldpe Films
Authors: Bobovitch A. L. , Elkoun S. , Ajji A.
Published: May 2006

Biaxially oriented linear low density polyethylene (LLDPE) films are produced using the double-bubble process with different machine direction (MD) orientation levels and the same transverse direction (TD) blow-up ratio. Their mechanical behavior is characterized in terms of the tensile strength and tear resistance. The microstructure and orientation are characterized using microscopy, x-ray diffraction (XRD), and Fourier transform infra red spectroscopy (FTIR). The results indicate that MD tensile strength increases with increasing MD stretching (draw) ratio while the TD tensile decreases. Tear resistance remains mainly constant in TD and decreases in MD with increases in draw ratio. Morphology analysis reveals that overstretching lamellae tend to align perpendicular to MD with an increase of their lamellar dimensions. c-axis orientation of lamellae in MD increases with draw ratio while a-and b-axes orient towards normal direction (ND) and TD respectively. A good correlation is observed between c-axis orientation and MD tear resistance and tensile strength.
Role of interphase precipitation in microalloyed hot strip steels
Authors: Kestenbach H.-J. , Campos S. S. , Morales E. V.
Published: May 2006

Transmission electron microscopy and microhardness measurements of individual ferrite grains were employed to investigate the state of interphase precipitation in commercial microalloyed steels. Interphase precipitation sheets tended to align parallel to the rolling plane, leading to frequent observation of particle row formation in longitudinal and transverse sample sections. As a rule, interphase precipitation occurred in some but not in all of the ferrite grains, thus limiting its contribution to the overall strength in comparison with carbonitride precipitation in austenite and dislocation hardening. In the particular case of a highly microalloyed Nb + Ti steel, interphase precipitation was present in about 50% of the ferrite grains. Interphase precipitation was also found to be associated with the loss of strength of as rolled steels due to normalising. In addition, arguments are presented to relate interphase precipitation to the effect of coiling temperature on as rolled strength.
Depth dependent hardness variation in Ni–P amorphous film under nanoindentation
Authors: Zhang B. , Wang W. , Zhang G. P.
Published: May 2006

The deformation behaviour and the depth dependent hardness variation in Ni–P amorphous alloy were investigated by nanoindentation. It was found that in addition to circular shear bands around the indent and on the indent surface, which have been previously observed, straight shear bands on the indent surface were also formed during nanoindentation. The indentation depth dependent hardness in the metallic glass is not modelled by the conventional dislocation based strain gradient theory for crystalline materials; instead it can be well described by a function of the inverse square root of the indentation depth. The structure evolution beneath the indentor is proposed to be the probable cause for the length scale dependent properties in metallic glass.
Electrochemical behaviour of chromium nitride coatings with various preferred orientations deposited on steel by unbalanced magnetron sputtering
Authors: Lee C. K.
Published: May 2006

Chromium nitride coatings Cr2N(111) and preferred orientations of CrN(111) and CrN(200) were successfully deposited on AISI 304 stainless steel by an unbalanced magnetron sputtering method. The electrochemical corrosion properties of the deposited films were studied in a 0·5M H2SO4 + 1M NaCl aqueous solution at ambient temperature by electrochemical measurements, including the corrosion potential Ecorr, linear polarisation, potentiodynamic polarisation and electrochemical impedance spectroscopy. The structural characterisation and surface morphology were investigated using X-ray diffraction, scanning electron microscopy and atomic force microscopy. The experimental results indicated that the CrN(200) coating possesses the best corrosion resistance property, followed by the CrN(111) coating, while the Cr2N coating has the least resistance among the three types of CrN(111), CrN(200) and Cr2N(111) coatings. The porosity, corresponding to the ratio of the polarisation resistance of the uncoated and the coated substrates, was higher in the Cr2N(111) coating than in the other CrN coatings. The CrN(200) coating had a dense microstructure almost without porosity. The void defects of CrN(111) and Cr2N(111) coatings are responsible for the decrease in corrosion protection.
Modelling the ‘universal’ dielectric response in heterogeneous materials using microstructural electrical networks
Authors: Bowen C. R. , Almond D. P.
Published: May 2006

The frequency dependent conductivity and permittivity of a ceramic composite are modelled using electrical networks consisting of randomly positioned resistors and capacitors. The electrical network represents a heterogeneous microstructure that contains both insulating (the capacitor) and conductive regions (the resistor). To validate model results, a model ceramic conductor–insulator composite was designed consisting of a porous lead zirconate titanate impregnated with different concentrations of water. Excellent agreement between experimental and model data was achieved with a strong correlation with many other ceramics, glasses and composites. It is proposed that the ‘universal’ dielectric response of many materials is a consequence of microstructural heterogeneity. The modelling approach could be used as a simple and effective method for microstructural design of ceramics and other materials with tailored dielectric properties.
Entropy generation analysis of turbulent transport in laser surface alloying process
Authors: Chatterjee D. , Chakraborty S.
Published: May 2006

A numerical formulation involving second law of thermodynamics is examined for analysis of three-dimensional surface tension driven turbulent transport during laser materials processing. A modified k– ϵ model is used to address turbulent melt pool convection in the presence of a continuously evolving phase change interface. Phase change aspects are addressed using a modified enthalpy–porosity technique. It is revealed that both energetic and exergetic efficiencies increase with increasing laser power, and remain insensitive to changes in powder feedrate over the range of parameters chosen. However, the energetic efficiency is found to increase with increasing laser scanning speed whereas the exergetic efficiency shows a reverse trend. Accordingly, a tradeoff in the laser scanning speed can be sought for while designing the process parameters, in order to ensure a maximum utilisation of the thermodynamic potential offered by the intense laser heat source.
Transmission electron microscopy study of copper–carbon nanocomposite
Authors: Carvalho P. A. , Fonseca I. , Marques M. T. , Correia J. B. , Vilar R.
Published: May 2006

A Cu–10C nanocomposite has been synthesised by high energy milling of elemental powders, followed by annealing at 873 K. Phase identification and microstructure characterisation have been carried out with transmission electron microscopy. Copper grain size ranged from 10 to 120 nm for the as milled material and from 10 to 150 nm after annealing. No graphite reflections could be detected by electron diffraction in either the as milled or annealed samples. Nevertheless, both conditions contain clusters of carbon of <10 nm, which could be of benefit for sliding wear applications. The lattice parameter measured after milling is compatible with a carbon solubility in the copper matrix ∼0·1 at.-%. The synthesised material showed excellent structural stability at 873 K, which is proposed to be dependent on solute drag effects resulting from boundary segregation. In fact, no grain boundary pinning by nanoparticles has been detected while a decrease in lattice parameter occurred during annealing.
Modelling flow stress behaviour of aluminium alloys during hot rolling
Authors: Serajzadeh S.
Published: May 2006

A mathematical model is proposed to predict the flow stress behaviour of aluminium alloys under hot rolling conditions. To do so, a dislocation model for evaluating flow stress during deformation is coupled with a finite element analysis to access metal behaviour under non-isothermal and variable strain rate conditions. Then, with the aid of the proposed model, a hot strip rolling process was simulated. In order to verify modelling results, flow stress behaviour of an aluminium alloy is studied employing hot compression tests in various temperatures and strain rates and the model was examined on this material. Non-isothermal hot rolling experiments were carried out and good agreement was found between predictions and experiments.