Experimental studies of lipped channel beams subject to web crippling under two-flange load cases

Lipped channel beams (LCBs) are commonly used as flexural members such as floor joists and bearers in the construction 6 industry. These thin-walled LCBs are subjected to specific buckling and failure modes, one of them being web crippling. Despite considerable 7 research in this area, some recent studies have shown that the current web crippling design rules are unable to predict the test capacities under 8 end-two-flange (ETF) and interior-two-flange (ITF) load conditions. In many instances, web crippling predictions by the available design 9 standards such as AISI S100, AS/NZS 4600 and Eurocode 3 Part 1-3 are inconsistent, i.e., unconservative in some cases, although they 10 are conservative in other cases. Hence, experimental studies consisting of 36 tests were conducted in this research to assess the web crippling 11 behavior and capacities of high-strength LCBs under two-flange load cases (ETF and ITF). Experimental results were then compared with the 12 predictions from current design rules. Comparison of the ultimate web crippling capacities from tests showed that the design equations are 13 very unconservative for LCB sections under the ETF load case and are conservative for the ITF load case. Hence, improved equations were 14 proposed to determine the web crippling capacities of LCBs based on the experimental results from this study. Current design equations do 15 not provide the direct strength method (DSM) provisions for web crippling. Hence, suitable design rules were also developed under the DSM 16 format using the test results and buckling analyses using finite-element analyses.

Experimental and numerical studies of hollow flange channel beams subject to web crippling under ETF and ITF load cases

This paper presents the details of experimental and numerical studies on the web crippling behaviour of hollow flange channel beams, known as LiteSteel beams (LSB). The LSB has a unique shape of a channel beam with two rectangular hollow flanges, made using a unique manufacturing process. Experimental and numerical studies have been carried out to evaluate the behaviour and design of LSBs subject to pure bending actions, predominant shear actions and combined actions. To date, however, no investigation has been conducted into the web crippling behaviour and strength of LSB sections under ETF and ITF load conditions. Hence experimental studies consisting of 28 tests were first conducted in this research to assess the web crippling behaviour and strengths of LSBs under two flange load cases (ETF and ITF). Experimental web crippling capacity results were then compared with the predictions from AS/NZS 4600 and AISI S100 design rules, which showed that AS/NZS 4600 and AISI S100 design equations are very unconservative for LSBs under ETF and ITF load cases. Hence improved equations were proposed to determine the web crippling capacities of LSBs. Finite element models of the tested LSBs were then developed, and used to determine the elastic buckling loads of LSBs under ETF and ITF load cases. New equations were proposed to determine the corresponding elastic buckling coefficients of LSBs. Finally suitable design rules were also developed under the Direct Strength Method format using the test results and buckling analysis results from finite element analyses.

Numerical modelling of rivet fastened rectangular hollow flange channel beams subject to shear

The intermittently rivet fastened Rectangular Hollow Flange Channel Beam (RHFCB) is a new cold-formed hollow section proposed as an alternative to welded hollow flange beams. Many experimental and numerical studies have been carried out in the past to investigate the shear behaviour of lipped channel beams. However, no research has been undertaken on the shear behaviour of rivet fastened RHFCBs. Therefore experimental and numerical studies were undertaken to investigate the shear behaviour and strength of rivet fastened RHFCBs. In this research finite element models of rivet fastened RHFCBs were developed to investigate their nonlinear shear behaviour including their buckling characteristics and ultimate shear strength. This paper presents the details of the finite element models of rivet fastened RHFCBs and the results. Both finite element analysis and experimental results showed that the current design rules are very conservative for the shear design of rivet fastened RHFCBs. Appropriate improvements have been proposed for the design rules of shear strength of rivet fastened RHFCBs within the Direct Strength Method format.

Many disciplines-common approach: Experiences in the development and delivery of an interprofessional health subject

In 2004, the Faculty of Health Sciences at La Trobe University in Victoria, Australia, introduced a new, final-year subject ‘Interdisciplinary Professional Practice’. The subject is taught to all students enrolled in the 11 allied health and human service disciplines at La Trobe University across metropolitan and rural campuses. The delivery is online to overcome timetabling barriers and to provide time and geographic flexibility. The subject is presented using an enquiry-based learning model. Students are exposed to the concepts of interdisciplinary teamwork through shared learning across professional boundaries to enable a collaborative workforce. An outline of the background development and design of this subject, and its implementation and content areas is presented. A discussion of relevant literature and an analysis of the subject evaluations and focus groups that have guided subject development to enhance student learning over eight cohorts is included.

Which Narrative? The Case of the Narrative Subject in Fifteenth-Century Altarpieces

The development of the altarpiece towards the end of the late medieval period added a new decorous and conspicuously visual element to the church interior. The altarpiece became the prime location for iconic – i.e. non-narrative – images, but almost from the beginning narrative images were part of the altarpiece in the form of small-scale pictures placed underneath or next to an iconic image in the centre. In the fifteenth century the format of the altarpiece gradually changed, and simultaneously with the development of the unified picture field some new narrative subjects began to appear on the central panel as the main subject of the altarpiece. During the course of the fifteenth century, narrative subjects became increasingly frequent and accepted subjects for altarpieces. In this article I will focus on the problem of the narrative altarpiece, a seeming contradiction of terms. As narrative subjects were transferred from their usual location to the central field of the altarpiece, traditionally reserved for the iconic image, the narrative was included in a new context and expected to assume the function of the altarpiece. How did a narrative image function in this context, and what kind of audience did it serve? Since the questions involved in the issue are complex, I will focus on the biblical narrative of The Visitation as a case study, and use two well-known Florentine altarpieces from the fifteenth century as examples of the interpretative choices open to the viewers of these altarpieces.

Subject Teacher Training and Teaching in English

The purpose of this Master s thesis is on one hand to find out how CLIL (Content and Language Integrated Learning) teachers and English teachers perceive English and its use in teaching, and on the other hand, what they consider important in subject teacher education in English that is being planned and piloted in STEP Project at the University of Helsinki Department of Teacher Education. One research question is also what kind of language requirements teachers think CLIL teachers should have. The research results are viewed in light of previous research and literature on CLIL education. Six teachers participate in this study. Two of them are English teachers in the comprehensive school, two are class teachers in bilingual elementary education, and two are subject teachers in bilingual education, one of whom teaches in a lower secondary school and the other in an upper secondary school. One English teacher and one bilingual class teacher have graduated from a pilot class teacher program in English that started at the University of Helsinki in the middle of the 1990 s. The bilingual subject teachers are not trained in English but they have learned English elsewhere, which is a particular focus of interest in this study because it is expected that a great number of CLIL teachers in Finland do not have actual studies in English philology. The research method is interview and this is a qualitative case study. The interviews are recorded and transcribed for the ease of analysis. The English teachers do not always use English in their lessons and they would not feel confident in teaching another subject completely in English. All of the CLIL teachers trust their English skills in teaching, but the bilingual class teachers also use Finnish during lessons either because some teaching material is in Finnish, or they feel that rules and instructions are understood better in mother tongue or students English skills are not strong enough. One of the bilingual subject teachers is the only one who consciously uses only English in teaching and in discussions with students. Although teachers good English skills are generally considered important, only the teachers who have graduated from the class teacher education in English consider it important that CLIL teachers would have studies in English philology. Regarding the subject teacher education program in English, the respondents hope that its teachers will have strong enough English skills and that it will deliver what it promises. Having student teachers of different subjects studying together is considered beneficial. The results of the study show that acquiring teaching material in English continues to be the teachers own responsibility and a huge burden for the teachers, and there has, in fact, not been much progress in the matter since the beginning of CLIL education. The bilingual subject teachers think, however, that using one s own material can give new inspiration to teaching and enable the use of various pedagogical methods. Although it is questionable if the language competence requirements set for CLIL teachers by the Finnish Ministry of Education are not adhered to, it becomes apparent in the study that studies in English philology do not necessarily guarantee strong enough language skills for CLIL teaching, but teachers own personality and self-confidence have significance. Keywords: CLIL, bilingual education, English, subject teacher training, subject teacher education in English, STEP

Media Education in the Finnish School System : A Conceptual Analysis of the Subject Didactic Dimension of Media Education

The aim of the doctoral dissertation was to further our theoretical and empirical understanding of media education as practised in the context of Finnish basic education. The current era of intensive use of the Internet is recognised too. The doctoral dissertation presents the subject didactic dimension of media education as one of the main results of the conceptual analysis. The theoretical foundation is based on the idea of dividing the concept of media education into media and education (Vesterinen et al., 2006). As two ends of the dimension, these two can be understood didactically as content and pedagogy respectively. In the middle, subject didactics is considered to have one form closer to content matter (Subject Didactics I learning about media) and another closer to general pedagogical questions (Subject Didactics II learning with/through media). The empirical case studies of the dissertation are reported with foci on media literacy in the era of Web 2.0 (Kynäslahti et al., 2008), teacher reasoning in media educational situations (Vesterinen, Kynäslahti - Tella, 2010) and the research methodological implications of the use of information and communication technologies in the school (Vesterinen, Toom - Patrikainen, 2010). As a conclusion, Media-Based Media Education and Cross-Curricular Media Education are presented as two subject didactic modes of media education in the school context. Episodic Media Education is discussed as the third mode of media education where less organised teaching, studying and learning related to media takes place, and situations (i.e. episodes, if you like) without proper planning or thorough reflection are in focus. Based on the theoretical and empirical understanding gained in this dissertation, it is proposed that instead of occupying a corner of its own in the school curriculum, media education should lead the wider change in Finnish schools.

Freezing of a colloidal liquid subject to shear flow

A nonequilibrium generalization of the density-functional theory of freezing is proposed to investigate the shear-induced first-order phase transition in colloidal suspensions. It is assumed that the main effect of a steady shear is to break the symmetry of the structure factor of the liquid and that for small shear rate, the phenomenon of a shear-induced order-disorder transition may be viewed as an equilibrium phase transition. The theory predicts that the effective density at which freezing takes place increases with shear rate. The solid (which is assumed to be a bcc lattice) formed upon freezing is distorted and specifically there is less order in one plane compared with the order in the other two perpendicular planes. It is shown that there exists a critical shear rate above which the colloidal liquid does not undergo a transition to an ordered (or partially ordered) state no matter how large the density is. Conversely, above the critical shear rate an initially formed bcc solid always melts into an amorphous or liquidlike state. Several of these predictions are in qualitative agreement with the light-scattering experiments of Ackerson and Clark. The limitations as well as possible extensions of the theory are also discussed.

The politics of forest bureaucracy as a subject of comparative studies.

XVIII IUFRO World Congress, Ljubljana 1986.

Guessing and compression subject to distortion

The problem of guessing a random string is revisited. The relation-ship between guessing without distortion and compression is extended to the case when source alphabet size is countably in¯nite. Further, similar relationship is established for the case when distortion allowed by establishing a tight relationship between rate distortion codes and guessing strategies.

Optimal maintenance policies for machines subject to deterioration and intermittent breakdowns

Optimal preventive maintenance policies, for a machine subject to deterioration with age and intermittent breakdowns and repairs, are derived using optimal control theory. The optimal policies are shown to be of bang-bang nature. The extension to the case when there are a large number of identical machines and several repairmen in the system is considered next. This model takes into account the waiting line formed at the repair facility and establishes a link between this problem and the classical ``repairmen problem.''

Optimal maintenance policy of a machine subject to failure

Optimal maintenance policies for a machine with degradation in performance with age and subject to failure are derived using optimal control theory. The optimal policies are shown to be, normally, of bang-coast nature, except in the case when probability of machine failure is a function of maintenance. It is also shown, in the deterministic case that a higher depreciation rate tends to reverse this policy to coast-bang. When the probability of failure is a function of maintenance, considerable computational effort is needed to obtain an optimal policy and the resulting policy is not easily implementable. For this case also, an optimal policy in the class of bang-coast policies is derived, using a semi-Markov decision model. A simple procedure for modifying the probability of machine failure with maintenance is employed. The results obtained extend and unify the recent results for this problem along both theoretical and practical lines. Numerical examples are presented to illustrate the results obtained.

Structure and deformation correlation of closed-cell aluminium foam subject to uniaxial compression

We report the results of an experimental and numerical study conducted on a closed-cell aluminium foam that was subjected to uniaxial compression with lateral constraint. X-ray computed tomography was utilized to gain access into the three-dimensional (3-D) structure of the foam and some aspects of the deformation mechanisms. A series of advanced 3-D image analyses are conducted on the 3-D images aimed at characterizing the strain localization regions. We identify the morphological/geometrical features that are responsible for the collapse of the cells and the strain localization. A novel mathematical approach based on a Minkowski tensor analysis along with the mean intercept length technique were utilized to search for signatures of anisotropy across the foam sample and its evolution as a function of loading. Our results show that regions with higher degrees of anisotropy in the undeformed foam have a tendency to initiate the onset of cell collapse. Furthermore, we show that strain hardening occurs predominantly in regions with large cells and high anisotropy. We combine the finite element method with the tomographic images to simulate the mechanical response of the foam. We predict further deformation in regions where the foam is already deformed. Crown Copyright (C) 2012 Published by Elsevier Ltd. on behalf of Acta Materialia Inc. All rights reserved.

Performance of inherently compensated flat pad aerostatic bearings subject to dynamic perturbation forces

The importance of air bearing design is growing in engineering. As the trend to precision and ultra precision manufacture gains pace and the drive to higher quality and more reliable products continues, the advantages which can be gained from applying aerostatic bearings to machine tools, instrumentation and test rigs is becoming more apparent. The inlet restrictor design is significant for air bearings because it affects the static and dynamic performance of the air bearing. For instance pocketed orifice bearings give higher load capacity as compared to inherently compensated orifice type bearings, however inherently compensated orifices, also known as laminar flow restrictors are known to give highly stable air bearing systems (less prone to pneumatic hammer) as compared to pocketed orifice air bearing systems. However, they are not commonly used because of the difficulties encountered in manufacturing and assembly of the orifice designs. This paper aims to analyse the static and dynamic characteristics of inherently compensated orifice based flat pad air bearing system. Based on Reynolds equation and mass conservation equation for incompressible flow, the steady state characteristics are studied while the dynamic state characteristics are performed in a similar manner however, using the above equations for compressible flow. Steady state experiments were also performed for a single orifice air bearing and the results are compared to that obtained from theoretical studies. A technique to ease the assembly of orifices with the air bearing plate has also been discussed so as to make the manufacturing of the inherently compensated bearings more commercially viable. (c) 2012 Elsevier Inc. All rights reserved.

Subject independent human action recognition using spatio-depth information and meta-cognitive RBF network

In this paper, we present a machine learning approach for subject independent human action recognition using depth camera, emphasizing the importance of depth in recognition of actions. The proposed approach uses the flow information of all 3 dimensions to classify an action. In our approach, we have obtained the 2-D optical flow and used it along with the depth image to obtain the depth flow (Z motion vectors). The obtained flow captures the dynamics of the actions in space time. Feature vectors are obtained by averaging the 3-D motion over a grid laid over the silhouette in a hierarchical fashion. These hierarchical fine to coarse windows capture the motion dynamics of the object at various scales. The extracted features are used to train a Meta-cognitive Radial Basis Function Network (McRBFN) that uses a Projection Based Learning (PBL) algorithm, referred to as PBL-McRBFN, henceforth. PBL-McRBFN begins with zero hidden neurons and builds the network based on the best human learning strategy, namely, self-regulated learning in a meta-cognitive environment. When a sample is used for learning, PBLMcRBFN uses the sample overlapping conditions, and a projection based learning algorithm to estimate the parameters of the network. The performance of PBL-McRBFN is compared to that of a Support Vector Machine (SVM) and Extreme Learning Machine (ELM) classifiers with representation of every person and action in the training and testing datasets. Performance study shows that PBL-McRBFN outperforms these classifiers in recognizing actions in 3-D. Further, a subject-independent study is conducted by leave-one-subject-out strategy and its generalization performance is tested. It is observed from the subject-independent study that McRBFN is capable of generalizing actions accurately. The performance of the proposed approach is benchmarked with Video Analytics Lab (VAL) dataset and Berkeley Multimodal Human Action Database (MHAD). (C) 2013 Elsevier Ltd. All rights reserved.