bluuebunny/crossref_metadata_2025 huggingface dataset:
Chineseness at the crossroads
Authors: Meerwald Agnes May Lin
Published: February 2009

This article interrogates the practices of Chineseness in the lives of women with Chinese backgrounds living in Australia. It suggests that these women are living in a space of ethnic liminality but that this condition is not limited to diasporic communities. It examines the experiences of migrant women and explores how this borderland space of blurred boundaries functions in the translation of diasporic ethnic subjectivities. It focuses on the processes of subjectification that produce ethnicities that are new but familiar, as the past interweaves with the present to create new but familiar versions of Chineseness. Within multicultural Australia, the production of hybrid ethnic subjectivities is in an increasing state of flux as the boundaries that segregate ethnicities become blurred, as experienced by many in postcolonial locations. This liminal limbo acknowledges the conflictual encounters of diasporic subjects as they negotiate what it means for them to be women with Chinese backgrounds in Australia.
‘Coming home’
Authors: Fortier Anne-Marie
Published: February 2009

This article proposes an examination of recent interventions in queer studies that project queer culture and politics within a diasporic framework. Drawing on written narratives of what may be termed ‘queer migrations’, I seek to map the intersections of queer memories and diasporic spaces as they are uttered in terms of ‘home’. By following the movement of queer subjects between homes, I examine how ‘home’, migration and belonging relate to each other in multiple ways. First, I discuss narratives of queer migration as homecoming, where ‘home’ is a destination rather than an origin. I explore the connection between exile, displacement and migration-as-homecoming found in some discussions on queer diaspora. How do the ‘homes’ people move towards relate to those that are ‘left behind’? How does the movement toward some ‘homes’ operate through the fixing of others? Second, I consider the movement back home, how home is reimagined or reconstituted through memories that challenge the assumed idea of home-as-familiarity. Drawing on autobiographical renditions of queer migrations and remembrances of home, I discuss Elspeth Probyn’s argument about movement, desire and childhood as ‘suspended beginnings’. If one can never return ‘home’, as Probyn argues, what are the effects of coming home again and again on definitions of home? Third, I wonder how memories of home can relocate queerness within the home without reinstating home as originary moment. Is it possible to conceive of being ‘at home’ in a way that already encounters/engenders queerness, but without deploying an originary narrative of ‘home’? Running through this discussion is a reflection about identity narratives that seek to reconfigure spaces of belonging shaped through both movement and attachment. Can we consider differential movements of subjects as not simply about thinking about home as mobile – not simply about the undoing of home as stasis – but as the re-forming of the very bounded spatiality of homes?
A fascinating spectacle of inconsistencies
Authors: Marschik Matthias
Published: February 2009

Much has been written about the `production' of sexuality in Nazi Germany; the specific ways of constructing male heroes and frail (but also strong) women coming together in a cold and distant way in the service of eugenics and a new society. Thus it was a national and political concept of sexuality in the narrow sense whereby sexuality was inextricably linked with the benefit of `Volk, Reich und Vaterland'. But an analysis of private photographs and the `unpolitical' sections of the newspapers of the period reveals elements of love and eroticism which indicate that, even in the Nazi context, the notion of an essential sexuality can be questioned. The article, on the one hand, discusses sexuality in the Nazi era from official and private photographs and, on the other hand, makes observations about the actuality of the Nazi concept even in (post)modern societies. The aim of the article is to look at a specific aspect of normality to obtain a more precise understanding of the Nazi era.
Reflections on cultural studies of technoscience
Authors: Reinel Birgit
Published: February 2009

This article argues for cultural studies of technoscience through the trajectory of public technoscience. Two key questions are addressed: why has there been relatively little cultural studies research on technoscience so far and how might this be explained? What may cultural studies contribute to the recently emerging, heterogeneous field of cultural studies of technoscience? To substantiate a cultural studies approach to public technoscience a ‘differentiating perspective on popularization’ is elaborated through the revised appropriation of Habermas’s work on the ‘public sphere’ and through the concept of ‘mediations’. Then a conceptualization of technoscience as ‘public story-telling and more’ is proposed, which draws on through the concepts of story-telling, myth and discourse inspired by the works of Donna Haraway, Roland Barthes and Michel Foucault respectively. Throughout the article the political significance of the symbolic dimensions of technoscience is highlighted.
Beauty and the beast
Authors: Béres Laura
Published: February 2009

This article examines the romantic portrayal of men’s control of women in such popular cultural texts as Beauty and the Beast and Bram Stoker’s Dracula. The author of this article has provided counselling services to abused women for many years. She describes the development of her concern in the meaning-making behaviours of abused women who engage with texts that romanticize abuse. A theoretical terrain is discussed, allowing for an unfixed positioning of both the writer and reader of the article, while considering the complex world of audience-text-academic.
The Discursive Construction of Professional Self Through Narratives of Personal Experience
Authors: DYER JUDY , KELLER-COHEN DEBORAH
Published: February 2009

Although the role played by narratives and particularly by narratives of personal experience in the construction of identity has been widely investigated, the presence and contribution of such narratives in institutional discourse has received comparatively little attention. Our study focuses on two narratives in university lectures, which show that such narratives are a means of textually constructing not only personal but also professional identities. Analysis reveals that the professors position themselves as experts, exploiting the use of pronouns and other referring expressions in addition to self and other evaluation, in order to distance themselves from non-expert others. In doing so, they make little use of the technical terminology often found in representations of professional selves. In offsetting self-aggrandizement with self-mockery, the professors' narratives display an ideological dilemma typical of the expert in current North American culture, which involves see-sawing between expressions of expertise and equality.
The Voice of Authority: The Local Accomplishment of Authoritative Discourse in Live News Broadcasts
Authors: RAYMOND GEOFFREY
Published: February 2009

Ever since language has been examined as a vehicle for action, scholars have been interested in its authorized use (Austin, 1962). Typically described under the rubric of `felicity conditions', the authorized use of language involves, among other conditions, the right or authority of a member to engage in, or deploy, some named action. This paper begins by examining how participants authorize the discourse of a co-interactant in one specialized setting: a live news broadcast. I argue that the successful exploitation by a reporter of his/her right to authoritatively describe a scene all are witnessing rests in part on the displayed mutual orientation of his or her co-interactants to that right through the local, contingently achieved deployment of complex discursive practices. After exploring the special case of live news broadcasts, I link this study to other studies of mass media that have explored the link between discursive practices in news broadcasts and reportorial authority. Finally, I argue that the resources I have identified have a more general provenance than live news broadcasts, and reflect on the relation between these findings and recent discussions that explore the authorized use of language.
Popping the question: questions and modality in written dating advertisements
Authors: Marley Carol
Published: February 2009

At the centre of the genre of dating advertisements is a tension between speech and writing, process and product, interaction and transaction. In this article I investigate some of the interpersonal resources available to writers of advertisements to achieve the goal of interacting in writing with a potential partner. I first consider the ways in which advertisers use questions and answers to enact and project speech-like interactional roles for themselves and their readers, in order to encourage an overt response to their textual initiations and open a conversation with a suitable partner. I then consider their use of modality to engage potential partners and negotiate mutual suitability. I conclude by comparing the generic function of these two areas of interpersonal resource and suggest a relationship of agnation between them.
Interpersonal metadiscourse: an indicator of interaction and identity
Authors: Abdi Reza
Published: February 2009

By using genre analysis, this study investigates the way writers use interpersonal metadiscourse to partly reveal their identity and examines their selected mode of interaction in two major academic fields: the social sciences (SS) and natural sciences (NS). A total of 55 academic research articles from the SS and NS were selected as the corpus of this study. A comparison of the two disciplines was made, based on the use of interpersonal metadiscourse through `hedges', `emphatics' and `attitude markers'. The analysis showed that the SS writers employed interpersonal metadiscourse more frequently than the NS writers. One-to-one comparison further showed that they varied significantly in their use of hedges and attitude markers but there was little difference in their use of emphatics. However, the use of hedges and emphatics was significantly different within each discipline. A qualitative in-depth analysis revealed that the choice of validity markers was closely related to the type of article being studied.
Resisting the incitement to talk in child counselling: aspects of the utterance `I don't know'
Authors: Hutchby Ian
Published: February 2009

Data from naturally occurring child counselling sessions are used to explore how counsellors seek to elicit therapeutically relevant talk in the face of resistance, or non-cooperation, from children. Focusing on a case in which a 6-year-old child persistently avoids collaborating in the kind of counselling talk that the counsellor is evidently aiming to produce, the analysis focuses both on the child's resistance strategies and on the counsellor's techniques for attempting to combat resistance and work towards a therapeutically relevant outcome. The article makes a contribution both to our understanding of the social and communicative competencies of children, especially in institutional settings, and to our understanding of the practices, discursive techniques and competencies of child counsellors.
“Are you losing your culture?”: poetics, indexicality and Asian American identity
Authors: Reyes Angela
Published: February 2009

This article examines a school district conference panel discussion to illustrate how `culture' is interactionally emergent and how `identity' is performatively achieved through struggles to position the self and other in socially meaningful ways. Analyzing an interaction between a panel of Asian American teens and an audience of teachers, advisors and administrators, the author traces how the term `culture' emerges as two constructs: `culture as historical transmission' and `culture as emblem of ethnic differentiation'. This is accomplished, in part, through emergent poetic and indexical patterning which shape categories and trajectories of personae to which speech event participants are recruited. It is argued that these two schemas of culture are not merely static essences, but dynamically linked to distinct participation frameworks which achieve particular performative effects. These schemas, which are brought into circulation, reveal how metalevel constructs, such as `identity politics' and `multiculturalism', are played out rather vividly in microlevel interaction.
Right and wrong: from philosophy to everyday discourse
Authors: Wierzbicka Anna
Published: February 2009

One of the most interesting phenomena in the history of the English language is the remarkable rise of the word right, in its many interrelated senses and uses. This article tries to trace the changes in the meaning and use of this word, as well as the rise of new conversational routines based on right, and raises questions about the cultural underpinnings of these semantic and pragmatic developments. It explores the hypothesis that the `discourse of truth' declined in English over the centuries; that the use of `right' and `wrong' as parallel concepts (and opposites) increased; and it notes that the use of right as an adjective increased enormously in relation to the use of true . Originally, right meant `straight', as in a right line (straight line). Figuratively, perhaps, this right in the sense `straight' was also used in an evaluative sense: `good', with an additional component building on the geometrical image: `clearly good'. Spoken of somebody else's words, “right” was linked (implicitly or explicitly) with `true'. But in the course of the 17th and 18th centuries right appears to have begun to be used more and more with reference to thinking rather than speaking. The association of right with thinking seems to have spread in parallel with a contrastive use of right and wrong — a trend apparently encouraged by the influence of the Reformation, especially within its Calvinist wing. Another interesting development is that over the last two centuries or so the discourse of `right' and `wrong' appears to have found a competitor in a discourse of `cooperation' and mutual concessions. Judging by both the frequency and range of its use, the word right flourished in this atmosphere, whereas wrong was increasingly left behind. This article traces the transition from the Shakespearean response “Right.”, described by the OED as `you are right; you speak well', to the present-day “Right.” of non-committal acknowledgement and it links the developments in semantics and discourse patterns with historical phenomena such as Puritanism, British empiricism, the Enlightenment and the growth of democracy.
Argumentation studies and discourse analysis: the French situation and global perspectives
Authors: Plantin Christian
Published: February 2009

This article focuses on the development of argumentation studies in France and their complex relations with discourse analysis. First, the meanings of the basic word `argument' in French and in American English are discussed and contrasted. Second, a brief historical section summarizes the complex history of rhetorical argumentation in France up until the late 1980s and the Perelmanian revival. Third, Grize `natural logic' and Anscombre and Ducrot `argumentation within language' are briefly discussed from the discourse analysis point of view. These programmes have restored argumentation study to favour in France, where it is currently the research paradigm most referred to in recent work. The fourth section examines the present situation in France which is characterized by a strong new interest in argumentation in all disciplines; this is fuelling a tendency towards the use of argumentation theories — classical or modern — for practical, short-term analysis purposes. Fifth, a proposal is made for a better integration of argumentation studies in discourse analysis, based on the conception of argumentation as opposite points of view, either in face-to-face disputes or in written arguments, sometimes lasting for several centuries. This article is based on the premise that research into the history of rhetoric and argumentation, as well as in specific discourse analytic trends that emerged in France during the 1970s, has some permanent value in that a better understanding of an academic discipline's historical development can be a good introduction to its current problems.
Accepting and rejecting advice as competent peers: caller dilemmas on a warm line
Authors: Pudlinski Christopher
Published: February 2009

This article examines caller responses to advice on three peer-run social support telephone lines for community mental health clients in the northeastern United States. Straightforward rejection of advice involves reports on past or current activities, known only to the caller, as a way of demonstrating one's competence in thinking up similar options. Straightforward acceptance of advice involves a report on activities the caller might do to adopt the advisable option. The most common responses, minimal acknowledgements, can potentially signify rejection, mere recipiency, and/or acceptance of the advice. Contrary to previous studies, minimal acknowledgements can display hesitant acceptance when subsequently accompanied by descriptions of additional details about a present or future action tied to the advisable option. These methods for accepting and rejecting advice help callers balance their needs for assistance, friendship and autonomy.
Using Sydney H. Gould's formalization of kin terminologies
Authors: Kronenfeld David B.
Published: February 2009

Parts of the formalism recently developed by Sydney H. Gould (Gould, 2000) are used to explore three interrelated problems relating to kinship terminologies. (1) What insights into the role of kinship in a modern society may be gained from a comparison of terminological variants in use within that society. (2) How we are to understand the relationship between skewed and unskewed variants of a terminology such as Fanti. (3) What may be some of the practical formal and cognitive constraints that affect possible transitions from one terminological type to another. Gould's algebraic definitions of the different system types is utilized – as is the graphic device, called a ‘kingraph’, which he developed to render the structure of the different types clear and to enable the easy tracing out of the terminological categories to which different relatives belong.
Marking theory and kinship analysis
Authors: Hage Per
Published: February 2009

The concept of marking was discovered in phonology by Trubetzkoy and generalized to morphology and grammar by Jakobson. In a fundamental application to anthropology, Greenberg integrated a generalized concept of marking into a cognitivelinguistic theory of kinship universals. Greenberg's theory is important for three reasons: (1) it leads to the discovery and explanation of cross-cultural universals in kinship classification; (2) it predicts the order in which kin terms evolve and establishes, thereby, criteria for evaluating alternative, competing reconstructions of kinship systems; (3) it provides a means for inferring features of prehistoric social organization. This paper illustrates these applications and points out the typological and cognitive implications of marking effects in kinship systems. The analysis demonstrates that a formal deductive approach to kinship can yield results not obtainable by more usual informal and inductive methods.
Aspects of a formalist theory of kinship
Authors: Lehman F. K.
Published: February 2009

I shall assume the general relevance of genealogy for kinship on the basis of my earlier paper (Lehman, 1993). I shall then proceed, first, to examine some further important formal properties of social structure that genealogy imposes on kinship categories. In particular, I shall argue that these make kinship the unique case of a truly ascribed, rather than achieved social structure. In that connection, I shall also show that the structure of the space of kin categories is therefore especially apt for purely formal analysis. I shall, furthermore, extend my earlier work on the category theoretical relation between the two spaces, demonstrating additional algebraic properties that follow from the way genealogical space provides the ground for the instantiation of kin categories, i.e. defining the notion of (possible) kin category occupancy. This, in turn, will involve specifying in detail the way (populations of) actual or supposed individuals are brought into the picture, and especially the way that conceptual/semantic features, derived from properties of persons, and how expectations about relations between them, are brought into and made part of the meaning of kin categories and their terminology. This is intended to be a further corrective critique of, for example, Schneider’s ‘cultural account’ theory of kinship theory, a critique founded upon the crucial requirement of keeping the notions of relational position and personal occupancy of that position analytically distinct.

At the same time I am also concerned to go beyond the question of the relation of genealogical space to kinship category spaces, and to pursue, however briefly, the more general point that kinship (and its associate relational system, marriage) are indeed algebraic spaces. To that extent I feel it important to argue that more encompassing questions about these domains are best addressed through the application of algebraic methods of analysis; that, in fact, the theory of such matters must itself, in the final analysis, be a mathematical object. To that end, though only in my conclusions, I shall present a preliminary demonstration of how such methods go far toward making sense of such larger problems concerning kinship and marriage – in this instance, a hitherto recalcitrant and misconstrued problem in the theory of marriage alliance, that of the systems of patrilateral marriage alliance.
Transforming Peoples and Subverting States
Authors: Feldman Alice
Published: February 2009

Recent debates underscore an increasing shift away from static conceptions of ethnicity and identity to an emphasis upon their more fluid and deconstructive qualities. The following examination of the international indigenous peoples’ movement demonstrates how the dynamic re-construction of indigenous identity and the discourses emanating from it are fundamental elements to successful mobilization. It also explores the ways in which the epistemologies underlying them are theoretically valuable and pragmatically transformative, and how they serve as the basis for developing a critical cultural pedagogy. It is argued that such a perspective would contribute to the development of a transformative and process-oriented approach to the conceptualization and study of ethnocultural mobilizations necessary for overcoming the constraints of western liberal thought and current preoccupations with ‘authenticity’ and typologies in related scholarship and practice.
National identities and representations of citizenship
Authors: Phalet Karen , Swyngedouw Marc
Published: February 2009

Postwar migration to European cities has led to the progressive decoupling of civil, social and political rights from national membership. With its linguistic divide and its intricate institutional architecture, the city of Brussels is a strategic research context for a critical test of the limits of prevailing national integration models and the emergence of post- or transnational forms of citizenship. The Brussels Minorities Survey was set up to compare identifications and representations of citizenship in random samples of Turkish and Moroccan minorities, and in a matched comparison sample of working-class Belgians. First, a comparison of Turkish, Moroccan and Belgian self-categorizations reveals the multiplication of ethnopolitical identities, along with the continuing importance of formal national membership for identity construction. Second, in the absence of formal political rights for non-EU citizens, Turkish and Moroccan experiences of citizenship are closely linked to their informal participation in ethnic and cross-ethnic organizations. Typically, ethnic and cross-ethnic forms of participation go hand in hand, with a common emphasis on cross-ethnic and conventional types of organization. Finally, Turkish and Moroccan representations of (dual) citizenship are multidimensional, allowing for multiple and selective combinations of participative, normative and identity dimensions across national contexts. While Turks and Moroccans share with Belgians a social contract type of citizenship in Belgium, they also adhere to a communal type of long distance citizenship in Turkey and Morocco which centres on a close linkage of national and religious attachments. We conclude that multiplicity is a key feature of minority perspectives on citizenship, so that active participation in the national context of residence is complemented by enduring ethnoreligious identification in the national context of origin.
Exploration and exploitation: internal variety and environmental dynamism
Authors: Kim Tohyun , Rhee Mooweon
Published: February 2009

This article proposes that specific features of environmental dynamism and the notion of internal variety should be taken into consideration in response to caveats in prior research on choice or balance between exploration and exploitation and its implications for organizational performance. The study extends March's exploration—exploitation model by (1) conceptualizing and varying two dimensions — amplitude and frequency — of environmental dynamism and (2) articulating the notion of internal variety in an organization. Results from the simulation models show how a combination of organizational practices shapes internal variety, which in turn influences an organization's level of knowledge over time amid a changing environment.The study's findings suggest that the level of internal variety, along with the mechanisms by which each practice influences internal variety, affect adaptations of organizational knowledge. Managing internal variety through a combination of strong complementary practices, rather than anchoring on moderate levels of those practices, can achieve the balance between exploration and exploitation.
Perceptions of Family of Origin Among Lonely Adult Filipino Males With Schizophrenia: A Qualitative Analysis
Authors: Porinchu Tharayil Davis
Published: February 2009

This study explored the perceived family life experiences in the family of origin among 35 hospitalized lonely adult (range 27 to 44 years) Filipino males with schizophrenia during a period of remission of their overt psychotic features. Open-ended interview, checklists, and projective techniques were used to collect data. Together with an in-depth analysis of narratives, the responses of the lonely and the loneliest participants were compared by Mann—Whitney U nonparametric test of comparison. It was predicted in this study that individuals with schizophrenia with higher level of loneliness would be more likely to perceive their family life experiences negatively than the less lonely individuals with schizophrenia. Results showed that the degree of negative family experiences among the loneliest participants was significantly higher than the lonely participants. Moreover, a few participants regardless of the degree of loneliness positively viewed their family as united and close, interactive, affectionate and loving, kind and good, trustworthy, religious, morally good, complete, and supportive.
Toxoplasma gondii glycosylphosphatidylinositols up-regulate major histocompatibility complex (MHC) molecule expression on primary murine macrophages
Authors: Debierre-Grockiego Françoise , Molitor Nicole , Schwarz Ralph T. , Lüder Carsten G.K.
Published: February 2009

Toxoplasma gondii is an obligatory intracellular parasite able to block the IFN-γ-induced up-regulation of major histocompatibility complex (MHC) class I and class II molecules. This facilitates parasite-mediated evasion of T-cell responses. Glycosylphosphatidylinositols (GPIs) are involved in the pathogenicity of protozoan parasites and we investigated if GPIs are responsible for inhibition of MHC expression on macrophages. In contrast to the blockade observed in cells infected with viable tachyzoites, T. gondii GPIs up-regulated MHC class I and class II molecules on the surface of both unstimulated and IFN-γ-stimulated primary murine macrophages. This effect was correlated to the ability of GPIs to increase the antigen presentation to CD8+ lymphocytes. T. gondii GPIs did not activate STAT1, one of the factors involved in the transcription of MHC class I and class II genes. However, the GPI-induced MHC class I up-regulation was abrogated by SN50, a specific NF-KB inhibitor. Up-regulation of surface MHC molecules by GPIs may lead to the elimination of non-infected cells of the host immune system, contributing to the immune escape strategy of T. gondii.
Synthetic peptides representing the N-terminal segment of surfactant protein C modulate LPS-stimulated TNF-α production by macrophages
Authors: Garcia-Verdugo Ignacio , Garcia de Paco Elvira , Espinassous Quentin , Gonzalez-Horta Azucena , Synguelakis Monique , Kanellopoulos Jean , Rivas Luis , Chaby Richard , Perez-Gil Jesús
Published: February 2009

Surfactant protein C (SP-C) consists of a hydrophobic α-helix inserted in pulmonary surfactant membranes, and a more polar N-terminal palmitoylated segment exposed to the aqueous phase. Previously, we showed that SP-C inserted in lipid vesicles interacts with bacterial lipopolysaccharide (LPS) and reduces LPS-elicited responses. As the N-terminal segment of SP-C was the most likely region responsible for these effects, a set of synthetic analogs of this stretch (SPC(1-13) ) were studied. Binding studies showed that SPC(1-13) binds LPS to the same extent as porcine SP-C under lipid-free conditions. In the absence of serum, both, palmitoylated and non-palmitoylated analogs enhanced the binding of tritiated LPS to macrophages as well as the LPS-induced production of TNF-α by these cells. These effects were reversed in the presence of serum; the analogs reduced the production of TNF-α in LPS-stimulated macrophages, probably by interfering with the formation of LPS/CD14/LBP complexes as suggested by analysis of the fluorescence emitted by a FITC derivative of Re-LPS. Our data indicate that water-soluble analogs of the N-terminal segment of SP-C can reduce LPS effects in the presence of serum, and thus might help in the design of new derivatives to fight endotoxic shock and pro-inflammatory events.
Parametric approach to positional fault detection in short arc welding
Authors: Li X. , Simpson S. W.
Published: February 2009

This work investigates a parametric technique for short arc welding fault detection. The independent component analysis algorithm is applied to split welding voltage and current signals into arcing and short circuiting regions. A series of parameters including means, medians and normalised inner products are calculated by processing the different sections of welding electrical data. Out of position welds in overlap joints are studied with investigation of the connection between parameters and short arc welding features. The effect of changing shielding gas is also illustrated. Figures of merit to quantify the change in various parameters between faulty and good welds are compared and discussed. It is shown that the data separation into two regions with independent component analysis is useful in providing various parameters that can assist in short arc welding fault detection under different conditions.
Metallographic and OIM study of weld cracking in GTA weld build-up of polycrystalline, directionally solidified and single crystal Ni based superalloys
Authors: Sidhu R. K. , Ojo O. A. , Richards N. L. , Chaturvedi M. C.
Published: February 2009

The repair of gas turbine components is of importance both commercially and scientifically to ensure cost effective repair schemes that will extend the lives of hot end components such as blades and stators. The present communication reports the results of a metallographic and orientation imaging microscopy study of weld cracking observed in the gas tungsten arc repair welds of a polycrystalline (IN738LC), a directionally solidified (Rene 80) and a proprietary single crystal (SX) alloy. The three alloys were welded with low, intermediate and high strength weld fillers, using a weld build-up approach rather than a conventional weld repair of a through thickness crack. This procedure would be applicable for example to worn area on the tips of turbine blades. Inhomogeneous initial microstructures and those from solidification processes led to extensive heat affected zone microfissuring in the IN738LC alloy, associated with MC carbide liquation, liquation of gamma prime ( γ′), segregation of boron and strain effects from precipitation of γ′ in both single and double pass welds. As observed previously in a V shaped weld preparation, the extent of microfissuring in alloy IN738LC increased substantially from the use of the low and intermediate strength weld fillers, to extensive heat affected zone microfissuring by using the high strength IN738 filler. In the directionally solidified Rene 80 welds, due to the reduction in grain boundary area per unit volume, only minor heat affected zone cracking was observed, while the SX alloy did not crack at all. The absence of any cracks in the SX alloy welds despite the presence of stray grains in the fusion zone appears to be related to reduced stress levels in the welds due to the choice of welding technique and the welding parameters.
Estimate of maximum pore size in keyhole laser welding of carbon steel
Authors: Beretta S. , Previtali B.
Published: February 2009

Porosity is easily formed in welded joints during high power laser welding due to keyhole instability. Large pores have detrimental effects on the fatigue resistance of a component and cause many failures in welded parts. This paper is aimed at predicting the maximum pore dimension in long laser welded joints, starting from the sampling of large pores in shorter joints. Two sampling strategies and, consequently, two estimating techniques, both belonging to the statistics of extremes, were explored. The first approach, extreme value type, is used to estimate the size of the maximum pore in each of a series of steel samples. In each sample, the larger single pore or two large pores which are very close are the measured maximum pore. The second approach, threshold value type, is used to estimate the size of pores larger than a critical threshold in a single sample of steel. Both approaches lead to good estimates of the largest pore distribution in short laser welded joints. However, the first one is more adequate to describe the largest pore distribution, because it allows the synergetic effect of two adjacent pores to be considered. In particular, the Gumbel distribution adequately fits the experimental data even in the case of welded joints 10 times longer than the investigated bead length.
Residual stress engineering in friction stir welds by roller tensioning
Authors: Altenkirch J. , Steuwer A. , Withers P. J. , Williams S. W. , Poad M. , Wen S. W.
Published: February 2009

The authors investigate the efficacy of applying rolling pressure along the weld line in thin butt welds produced using friction stir welding (FSW) as a means of controlling the welding residual stresses. Two cases are examined and in each case, comparison is made against the as welded condition. First, for FSW of AA 2024 aluminium alloy, roller tensioning was applied during welding using two rollers placed behind and either side of the FSW tool. Very little effect was seen for the down forces applied (0, 50, 75 kN). Second, for FSW AA 2199 aluminium alloy, post-weld roller tensioning was applied using a single roller placed directly on the FS weld line. In this case, significant effects were observed with increased loading, causing a marked reduction in the longitudinal tensile residual stress. Indeed, a load of just 20 kN was sufficient to reverse the sign of the weld line residual stress. Only slight differences in Vickers hardness were observed between the different applied loads. Furthermore, unlike some methods, this method is cheap, versatile and easy to apply.
Application of rotating arc system to horizontal narrow gap welding
Authors: Yang C. L. , Guo N. , Lin S. B. , Fan C. L. , Zhang Y. Q.
Published: February 2009

A rotating arc system for narrow gap horizontal welding was developed for solving the problem that the molten pool sagged due to the gravity. The characteristic of the system was that the synchronous rotation of nozzle and wire was generated by eccentric sleeve driven by motor. This process not only may reduce welding effective heat input due to an increase in the welding instantaneous velocity but also may disperse arc force which could counteract the gravity of upper side of molten metal. Both the two aspects were beneficial for horizontal weld formation. Experimental results indicated that shapely horizontal joint could be obtained in appropriate rotating parameters. The asymmetry of joint formation indicated that the heat affected zone width and microstructure in upper side were larger than that in lower side. The effective heat input difference near each side caused by the instantaneous velocity difference was the main reason why the formation characteristics occurred.
Improved process stability during friction stir welding of 5 cm thick copper canisters through shoulder geometry and parameter studies
Authors: Cederqvist L. , Sorensen C. D. , Reynolds A. P. , Öberg T.
Published: February 2009

The spent nuclear fuel from Swedish power plants will be placed in copper canisters that are sealed with friction stir welding and the stability and robustness of this process is now being optimised in three steps: first, the shoulder geometry was identified that produced the most stable weld cycle, then the welding parameters were optimised for that geometry with regards to stability, and finally, the chosen geometry and welding parameters were verified and evaluated during multiple weld cycles. The shoulder study showed that stable welds could be produced repeatedly with a convex scroll geometry which proved more stable than various concave and flat scroll geometries. In the subsequent parameter study, not only were the most stable values for the welding parameters derived, but a clear relationship was shown between power input and tool temperature. This relationship can be used to more accurately control the process within the parameter windows, not only for this application but for other applications where the welding temperature needs to be kept within a specified range. Similarly, the potential of the convex scroll shoulder geometry for use in applications with other metals and thicknesses is evident.
Mathematical modelling of superalloy remelting operations
Authors: Jardy A. , Ablitzer D.
Published: February 2009

In order to produce Ni base superalloys for a critical use, it is necessary to control the whole processing route, and especially to master the solidification process. Thus, an essential step is the consumable electrode remelting operation (electroslag remelting or vacuum arc remelting) which produces the solidified ingot. Both processes are characterised by a fair control of the melting rate and a high cooling rate, even for large diameter ingots. Studies based on mathematical modelling and numerical simulation enable one to link the local solidification conditions to the operating parameters. The present paper discusses the use and validation of numerical models for secondary melting. It is shown that modelling is a valuable tool for superalloy producers to prevent features such as white spot formation and to predict freckling tendency.
A multicomponent diffusion model for prediction of microstructural evolution in coated Ni based superalloy systems
Authors: Karunaratne M. S. A. , Ogden S. L. , Kenny S. D. , Thomson R. C.
Published: February 2009

A multicomponent model which can simulate the microstructural evolution of a coated Ni based superalloy system has been developed. The model consists of a one-dimensional finite difference diffusion solver to calculate the component distribution, a power law based model for predicting surface oxidation and a thermodynamic calculation routine for determining the phase evolution. Apart from forecasting concentration and phase profiles after a given thermal history, the model can estimate the losses due to oxidation and the remaining life of a coating based on a concentration and/or phase fraction dependent failure criteria. The phase constitution and concentration profiles predicted by the model have been compared with an experimental NiCoCrAlY coated CMSX-4 system, aged for times up to 10 000 h between 850 and 1050°C, and many experimental features can be predicted successfully by the model. The model is expected to be useful for assessing microstructural evolution of coated turbine blade systems.
Developments in superalloy castability and new applications for advanced superalloys
Authors: Harris K. , Wahl J. B.
Published: February 2009

Increasing emphasis is being paid to optimising castability of cast superalloys to absolutely minimise defects which impact casting yield and alloy performance and to improve structural weldability of weld repairable alloys. The objective is to maximise casting yield and quality and minimise any rectification costs. To accomplish these aims the controls on deleterious elements such as [N], [O], S, P and Si at the ppm level, including accurate measurement, are critical. Conversely, the addition of highly reactive elements, La and Y at the ppm level, in conjunction with very low (1 ppm or less) sulphur content has dramatically improved bare oxidation resistance (for unshrouded blade tip life) and thermal barrier coating (TBC) adherence and life including prime reliant applications. This technology has been applied to the following new or improved cast superalloys: CM 939 Weldable®, CMSX-486® and CMSX-4® (SLS) [La+Y] (Cannon-Muskegon Corporation). In this paper, the role (both positive and negative) and control of critical elements at the ppm level as it applies to many advanced superalloys will be examined and discussed.
Microstructural aspects of high temperature deformation of monocrystalline nickel base superalloys: Some open problems
Authors: Mughrabi H.
Published: February 2009

Some open questions concerning the microstructural mechanisms which govern the high temperature strength of monocrystalline nickel base superalloys will be reviewed in the context of previous work. Emphasis will be laid on microstructural effects observed in microyielding, creep, isothermal and thermomechanical fatigue and on the role of the γ/ γ′ lattice misfit with respect to γ/ γ′ rafting. The conditions for cutting of the γ′ rafts will be stated in a simplified two-dimensional dislocation model. Effects of the connectivity of the coarsened γ/ γ′ microstructure and of the orientation of γ/ γ′ rafts on the strength properties will be discussed, and potentially beneficial effects of a positive lattice misfit will be addressed. Attention will be drawn to counteracting alloying effects which modify both the lattice mismatch and the diffusion kinetics. The main conclusion is that the optimisation of superalloy properties can only be sought in improving the most important properties without deterioration of other desirable properties.
Measurement and estimation of thermophysical properties of nickel based superalloys
Authors: Quested P. N. , Brooks R. F. , Chapman L. , Morrell R. , Youssef Y. , Mills K. C.
Published: February 2009

Thermophysical properties for the solid and liquid phases of several Ni based superalloys (CMSX-4, CMSX-10, CM186LC, IN 738 and Rene 80) have been measured. The following properties were measured: heat capacity and enthalpy, thermal expansion coefficient and density, thermal diffusivity, viscosity and surface tension. Analysis of these measurements showed that that γ′ phase (Ni3Al) affected the values for the following properties; Cp, enthalpy, electrical resistivity, thermal diffusivity and conductivity. Relationships have been identified between properties and the γ′ phase content (which can be represented by mass% Al in the alloy). These relations were then used to calculate property values of the alloys from chemical composition. Other relations were developed to estimate the viscosities and surface tensions of Ni based superalloys. The predicted property values were found to be in good agreement with the measured values.
On oxidation behaviour of platinum aluminide coated nickel based superalloy CMSX-4
Authors: Reed R. C. , Wu R. T. , Hook M. S. , Rae C. M. F. , Wing R. G.
Published: February 2009

The effects of platinum modification on the isothermal oxidation performance of a chemical vapour deposition aluminide coating are examined. Platinum was electrodeposited to varying thicknesses (to a maximum of 16 μm) onto the CMSX-4 single crystal superalloy, before applying a high temperature/low activity aluminisation process. The oxidation performance at 1100°C improved monotonically with increasing Pt thickness; this was confirmed by thermal gravimetric analysis. The degree of rumpling of the alumina scale was also decreased with increasing platinum. The superior oxidation resistance of platinum modified aluminide coatings is a consequence of the β-NiAl formed during aluminisation containing an enhanced Al/Ni ratio, reduced levels of Co and Ti and decreased concentrations of the refractory elements Re, W and Ta. This seems to be due at least in part to the microstructural effects caused by the prior diffusion of platinum into the surface, which causes the generation of a γ-(Ni,Pt)/ γ′-(Ni,Pt)3Al microstructure; the upper portion of the Pt diffused coating comprises predominantly the γ′-(Ni,Pt)3Al phase which is rich in Pt and Al and depleted in Co and the refractory elements W and Re. The ramifications of our findings for the design of bond coats required for thermal barrier coating systems are discussed.
Coupled modelling of solidification and solution heat treatment of advanced single crystal nickel base superalloy
Authors: Warnken N. , Larsson H. , Reed R. C.
Published: February 2009

Two numerical models to simulate microsegregation and phase formation during directional solidification and subsequent solution heat treatment of an advanced experimental ruthenium containing single crystal nickel base superalloy are tested and compared. The first method is based on a one-dimensional front tracking for the primary solidification and a homogenisation method for the final stages of solidification as well as for the solution heat treatment. Calculations for this model are carried out in one-dimension using cylindrical coordinates. The second is based upon the phase field method, applied to solidification and subsequent solution heat treatment, where calculations are carried out in two-dimension. Both models are coupled to thermodynamic and kinetics databases modelled according to the CALPHAD method. A concept of computer based optimisation of solution heat treatments is proposed. The results show that both methods are capable of handling the complexity of contemporary superalloys, and realistic results are obtained from both models.
Comparison of empirical and physical deformation maps for Nimonic 90
Authors: Harrison G. F. , Evans W. J. , Winstone M. R.
Published: February 2009

The paper presents a brief overview of the Graham and Walles creep modelling concept and of its application to the wrought nickel alloy Nimonic 90. Creep rupture data of up to 50 000 h duration together with a reduced set of steady state creep data are used to demonstrate how these data can be used to construct a creep deformation map within which specific sets of model parameters operate. It is then shown how the map can be matched directly to the underlying physical processes.