1,456 research outputs found

    A Model for Viscoelastic Consolidation of Wood-Strand Mats. Part II: Static Stress-Strain Behavior of the Mat

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    A solid mechanics model is developed to predict the static stress-strain behavior of randomly formed wood-strand mats during pressing. The procedure includes a Monte Carlo simulation for reconstructing the mat structure. During the early stages of mat displacement, the model computes the cumulative stress development from strand bending. As consolidation continues, the overlapping strands form solid columns. Hooke's Law, modified by a nonlinear strain function, governs the stress development in a finite number of these imaginary columns comprising the mat. Experimental results showed good agreement with the predicted stress response

    A Model for Viscoelastic Consolidation of Wood-Strand Mats. Part I. Structural Characterization of the Mat Via Monte Carlo Simulation

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    A procedure using Monte Carlo simulation was developed to characterize the spatial structure of randomly formed, wood-strand mats. The simulation reproduces the number of strands in the centroids of imaginary strand columns of finite size. The vertical distances between the adjacent strands and the location of the column centroid relative to the constant length of each strand are also simulated. A data base was collected on realistic mats produced from strands of constant size and non-planar geometries (i.e., random bow, cup, and twist). The procedure can be used in a model for predicting the mechanical behavior of random strand mats during consolidation

    Reducing Moisture Swell of Densified Wood With Polycarboxylic Acid Resin

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    A water-soluble polycarboxylic acid (PCA) resin was assessed for ability to limit moisture swelling of densified wood. Aspen flakes were treated in 0 (control), 1, 5, 10, and 20% PCA resin solutions and drained for 1, 10, and 20-min time periods. Following treatments, flakes were compressed to roughly 50% strain at 170°C. The PCA content of flakes significantly increased with increasing concentration and drain time. Water absorption and thickness swell of flakes decreased with increasing PCA content. Both water absorption and thickness swell of untreated flakes were over 100%; but for PCA-treated flakes, water absorption and thickness swell as low as 45% and 16%, respectively, were achieved. Irreversible thickness swell decreased with increasing PCA content, while reversible thickness swell remained relatively constant. The swelling coefficient decreased with increasing PCA content, a behavior that often is associated with bulking agents for treated, uncompressed wood. However, dynamic mechanical analysis further suggested that PCA resin acts as a cross-linking agent to stabilize the position of the collapsed cell walls

    Fundamentals of Flakeboard Manufacture: Viscoelastic Behavior of the Wood Component

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    Theories of the viscoelastic behavior of amorphous polymers are reviewed and are used to describe the density gradient formation in flakeboard. This technique utilizes measured temperature and gas pressure at discrete locations inside a flake mat during hot pressing to predict the glass transition temperature of wood as a function of press time. The difference between the flake temperature and the predicted glass transition temperature is a relative indicator of the amount of flake deformation and stress relaxation at a location in the mat. A knowledge of the stress history imposed in the mat is then used to relate flake deformation and stress relaxation to the formation of a density gradient. This analysis allows for a significant portion of the density gradient to develop after the hot press has closed. Experimental data for various density gradients support the theories presented here

    Ethical issues in the use of in-depth interviews: literature review and discussion

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    This paper reports a literature review on the topic of ethical issues in in-depth interviews. The review returned three types of article: general discussion, issues in particular studies, and studies of interview-based research ethics. Whilst many of the issues discussed in these articles are generic to research ethics, such as confidentiality, they often had particular manifestations in this type of research. For example, privacy was a significant problem as interviews sometimes probe unexpected areas. For similar reasons, it is difficult to give full information of the nature of a particular interview at the outset, hence informed consent is problematic. Where a pair is interviewed (such as carer and cared-for) there are major difficulties in maintaining confidentiality and protecting privacy. The potential for interviews to harm participants emotionally is noted in some papers, although this is often set against potential therapeutic benefit. As well as these generic issues, there are some ethical issues fairly specific to in-depth interviews. The problem of dual role is noted in many papers. It can take many forms: an interviewer might be nurse and researcher, scientist and counsellor, or reporter and evangelist. There are other specific issues such as taking sides in an interview, and protecting vulnerable groups. Little specific study of the ethics of in-depth interviews has taken place. However, that which has shows some important findings. For example, one study shows participants are not averse to discussing painful issues provided they feel the study is worthwhile. Some papers make recommendations for researchers. One such is that they should consider using a model of continuous (or process) consent rather than viewing consent as occurring once, at signature, prior to the interview. However, there is a need for further study of this area, both philosophical and empirical

    Resist, comply or workaround? An examination of different facets of user engagement with information systems

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    This paper provides a summary of studies of user resistance to Information Technology (IT) and identifies workaround activity as an understudied and distinct, but related, phenomenon. Previous categorizations of resistance have largely failed to address the relationships between the motivations for divergences from procedure and the associated workaround activity. This paper develops a composite model of resistance/workaround derived from two case study sites. We find four key antecedent conditions derived from both positive and negative resistance rationales and identify associations and links to various resultant workaround behaviours and provide supporting Chains of Evidence from two case studies

    Toward a Social Practice Theory of Relational Competing

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    This paper brings together the competitive dynamics and strategy-aspractice literatures to investigate relational competition. Drawing on a global ethnography of the reinsurance market, we develop the concept of micro-competitions, which are the focus of competitors’ everyday competitive practices. We find variation in relational or rivalrous competition by individual competitors across the phases of a micro-competition, between competitors within a micro-competition, and across multiple micro-competitions. These variations arise from the interplay between the unfolding competitive arena and the implementation of each firm’s strategic portfolio. We develop a conceptual framework that makes four contributions to: relational competition; reconceptualizing action and response; elaborating on the awareness-motivation-capability framework within competitive dynamics; and the recursive dynamic by which implementing strategy inside firms shapes, and is shaped by, the competitive arena

    Producing persuasive findings: Demystifying ethnographic textwork in strategy and organization research

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    Despite the importance and proliferation of ethnography in strategy and organization research, the central issue of how to present ethnographic findings has rarely been discussed. Yet, the narratives we craft to share our experience of the field are at the heart of ethnographic papers and provide the primary basis for our theorizing. In this article, we explain the “textwork” involved in writing persuasive findings. We provide an illustrative example of ethnographic data as it is recorded within fieldnotes and explain the necessary conceptual and writing work that must be done to render such data persuasive, drawing on published exemplars of ethnographic articles. This allows us to show how such texts, through various forms of writing and data representation, are transformed from raw fieldnotes to comprehensible findings. We conclude by asserting the value of these specifically ethnographic ways of presenting evidence, which are at odds with the canonical methods of data presentation in management studies

    Reflections on a degree initiative: the UK's Birmingham Royal Ballet dancers enter the University of Birmingham

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    This paper provides an opportunity to share experiences and perceptions of the first 5 years of a degree programme for professional dancers. A partnership developed in the mid-1990s between the UK's Birmingham Royal Ballet and the University of Birmingham, Westhill (now School of Education), to provide a part-time, post-experience, flexible study programme for full-time Company dancers. This is the first 'company customised' higher education programme to dovetail studies around rehearsal, performance and touring schedules. Methodology is based on a narrative by the author, informed by ongoing internal and external evaluations, in-depth interviews with dancers and Company managers, documentation and secondary sources. Outcomes indicate that the programme has made a positive difference to the Company, to the dancers and to the wider education and dance/arts world

    Walking the walk: a phenomenological study of long distance walking

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    Evidence suggests that regular walking can elicit significant psychological benefits although little evidence exists concerning long distance walking. The purpose of this study was to provide detailed accounts of the experiences of long distance walkers. Phenomenological interviews were conducted with six long distance walkers. Data were transcribed verbatim before researchers independently analyzed the transcripts. Participants reported a cumulative effect with positive feelings increasing throughout the duration of the walk. Long distance walking elicited positive emotions, reduced the effects of life-stress, and promoted an increased sense of well-being and personal growth. Results are aligned to theories and concepts from positive psychology
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