On a three-dimensional lattice approach for modelling corrosion induced cracking and its influence on bond between reinforcement and concrete

The present work involves the discrete modelling of corrosion induced cracking and its influence on the bond between reinforcement and concrete. A lattice approach is used to describe the mechanical interaction of a corroding reinforcement bar, the surrounding concrete and the interface between steel reinforcement and concrete. The cross-section of the ribbed reinforcement bar is taken to be circular, assuming that the interaction of the ribs of the deformed reinforcement bar and the surrounding concrete is included in a cap-plasticity interface model. The expansion of the corrosion product is represented by an eigenstrain in the lattice elements forming the interface. The lattice modelling approach is applied to the analysis of corrosion induced cracking and its influence of the bond strength. The model capabilities are assessed by comparing results of analyses with those from unconfined pull-out tests reported in the literature. Future work will investigate the influence of the stiffness of interface elements and the effect of lateral confinement on corrosion induced cracking.Comment: Preprint of conference paper for Fracture Mechanics of Concrete and Concrete Structures, South Korea, 201

Strength Regain of Clay Slurry using Additives

This report provides a comprehensive account of the data and observations gained from the research work carried out at the Department of Civil Engineering, Glasgow University on this 4-month contract funded by Technip UK Ltd from December 1st, 2009 to March 31st, 2010. The principal objective of the project was to determine by experiment which, if any, of a group of chemical additives were effective in accelerating the regain of strength of a marine clay following gross disturbance/remoulding by injection of water (and consequent increase in water content). The results of the test programme suggest that dosing with Calcium Hydroxide yields very promising results, and these results are presented at length. Other results are reported in the appendices and only briefly discussed herein.<p></p> Towards the end of the contract, further testing of the effect of the Calcium Hydroxide additive was undertaken at lower water contents than originally specified. In addition, some long-term tests (up to one year), which fall outside the scope of the contract, are currently being undertaken to establish whether the observed strength gain is permanent.<p></p&gt

Incorporating creativity into teachers practice and self-concept of professional identity

The study explores what happens to teachers practice and ’ professional identity when they adopt a collaborative action research approach to teaching and involve external creative partners and a university mentor. The teachers aim to nurture and develop the creative potential of their learners through empowering them to make decisions for themselves about their own progress and learning directions. The teachers worked creatively and collaboratively designing creative teaching and learning methods in support of pupils with language and communication difficulties. The respondents are from an English special school, primary school and girls secondary school. A mixed methods methodology is adopted. Gains in teacher confidence and capability were identified in addition to shifts in values that impacted directly on their self-concept of what it is to be an effective teacher promoting effective learning. The development of their professional identities within a team ethos included them being able to make decisions about learning that are based on the educational potential of learners that they proved resulted in elevated standards achieved by this group of learners. They were able to justify their actions on established educational principles. Tensions however were revealed between what they perceived as their normal required professionalism imposed by external agencies and the enhanced professionalism experienced working through the project where they were able to integrate theory and practice

Out there and in here: design for blended scientific inquiry learning

One of the benefits of mobile technologies is to combine ‘the digital’ (e.g., data, information, photos) with ‘field’ experiences in novel ways that are contextualized by people’s current located activities. However, often cost, mobility disabilities and time exclude students from engaging in such peripatetic experiences. The Out There and In Here project, is exploring a combination of mobile and tabletop technologies in support for collaborative learning. A system is being developed for synchronous collaboration between geology students in the field and peers at an indoor location. The overarching goal of this research is to develop technologies that support people working together in a suitable manner for their locations. There are two OTIH project research threads. The first deals with disabled learner access issues: these complex issues are being reviewed in subsequent evaluations and publications. This paper will deal with issues of technology supported learning design for remote and co-located science learners. Several stakeholder evaluations and two field trials have reviewed two research questions: 1. What will enhance the learning experience for those in the field and laboratory? 2. How can learning trajectories and appropriate technologies be designed to support equitable co-located and remote learning collaboration? This paper focuses on describing the iterative linked development of technologies and scientific inquiry pedagogy. Two stages within the research project are presented. The 1st stage details several pilot studies over 3 years with 21 student participants in synchronous collaborations with traditional technology and pedagogical models. Findings revealed that this was an engaging and useful experience although issues of equity in collaboration needed further research. The 2nd stage, in this project, has been to evaluate data from over 25 stakeholders (academics, learning and technology designers) to develop pervasive ambient technological solutions supporting orchestration of mixed levels of pedagogy (i.e. abstract synthesis to specific investigation). Middleware between tabletop ‘surface’ technologies and mobile devices are being designed with Microsoft and OOKL (a mobile software company) to support these developments. Initial findings reveal issues around equity, ownership and professional identity

Modelling and creativity in design and technology

Recent OFSTED reviews of inspection findings emphasise that whilst pupils at all key stages are enthusiastic and well-motivated when engaged in design and technology, confidence and competence vary with the effectiveness of teaching, the degree of challenge of the task and the opportunities given to be creative and to work independently. This paper will present the work done in the early stages of development of a PhD research programme concerned with examining the role of creativity in the teaching and learning of design and technology. Design activity generally is characterised by attempts to solve ill-defined problems based on an understanding of the present world, not the one for which the solution to the problem is expected to meet. Consequently, some form of 'creative leap' on the part of the designer is required to produce solutions that are never right or wrong, only better or worse. In the classroom, the careful framing of problems and the persuasiveness and positive leadership offered by the teacher can promote growth in the sophistication of pupils' models and responses to situations encountered. The paper will explore the range of factors likely to influence the achievement of success: a) by designers; b) by teachers and learners working on design problems; through the construction of, and interplay, between expressed and mental models

Applications and interpretation of krypton 81m ventilation/technetium 99m macroaggregate perfusion lung scanning in childhood

Radionuclide ventilation perfusion lung scans now play an important part in the investigation of paediatric lung disease, providing a safe, noninvasive assessment of regional lung function in children with suspected pulmonary disease. In paediatric practice the most suitable radionuclides are Krypton 81m (Kr81m) and Technetium 99m (Tc99m), which are jointly used in the Kr81m ventilation/Tc99m macroaggregate perfusion lung scan (V/Q lung scan). The Kr81m ventilation scan involves a low radiation dose, requires little or no subject cooperation and because of the very short half life of Kr81m (13 seconds) the steady state image acquired during continuous inhalation of the radionuclide is considered to reflect regional distribution of ventilation. It is now the most important noninvasive method available for the investigation of the regional abnormalities of ventilation characteristic of many congenital and acquired paediatric respiratory diseases, such as diaphragmatic hernia, pulmonary sequestration, bronchopulmonary dysplasia, foreign body inhalation and bronchiectasis. It improves diagnostic accuracy, aids clinical decision making and is used to monitor the progress of disease and response to therapy. Theoretical analysis of the steady state Kr81m ventilation image suggests that it may only reflect regional ventilation when specific ventilation (ventilation per unit volume of lung) is within or below the normal adult range (1-3 L/L/min). At higher values such as those seen in neonates and infants (8-15 L/L/min) Kr81m activity may reflect regional lung volume rather than ventilation, a conclusion supported by the studies of Ciofetta et al. There is some controversy on this issue as animal studies have demonstrated that the Kr81m image reflects ventilation over a much wider range of specific ventilation (up to 13 L/L/min). A clinical study of sick infants and very young children is in agreement with this animal work and suggests that the steady state Kr81m image still reflects regional ventilation in this age group. The doubt cast on the interpretation of the Kr81m steady state image could limit the value of V/Q lung scans in following regional lung function through childhood, a period when specific ventilation is falling rapidly as the child grows. Therefore the first aim of this study was to examine the application of this theoretical model to children and determine whether the changing specific ventilation seen through childhood significantly alters the interpretation of the steady state Kr81m image. This is a necessary first step before conducting longitudinal studies of regional ventilation and perfusion in children. The effect of posture on regional ventilation and perfusion in the adult human lung has been extensively studied. Radiotracer studies have consistently shown that both ventilation and perfusion are preferentially distributed to dependent lung regions during tidal breathing regardless of posture. There is little published information concerning the pattern in children yet there are many differences in lung and chest wall mechanics of children and adults which, along with clinical observation, have led to the hypothesis that the pattern of regional ventilation observed in adults may not be seen in children. Recent reports of regional ventilation in infants and very young children have provided support for this theory. The paper of Heaf et al demonstrated that these differences may in certain circumstances be clinically important. It is not clear however at what age children adopt the "adult pattern of ventilation". In addition to the problems referred to above, attenuation of Kr81m activity as it passes through the chest wall and the changing geometry of the chest during tidal breathing have made quantitative analysis of the image difficult although fractional ventilation and perfusion to each lung can be calculated from the steady state image. In clinical practise, therefore, ventilation and perfusion are usually assessed by inspection of the steady state image. The aims of the present study were therefore: 1. To critically assess Kr81m ventilation and Tc99m MAA perfusion images in children. 2. To derive fractional ventilation and perfusion to each lung in children with normal chest radiography and homogeneous distribution of the radionuclides. 3. To conduct further studies into the effects of gravity on regional lung function. 4. To apply the technique in clinical practise. 5. To attempt to improve quantitation of the Kr81m ventilation image

Data Journalism Classes in Australian Universities: Educators Describe Progress to Date

This article examines the extent to which data journalism (DJ) is being taught in Australian universities. It presents the results of interviews with 35 journalism academics about how they are incorporating data journalism into their courses. It includes details about the types of data journalism skills they are teaching, the resources they are using and the hindrances that have met or are making it difficult to teach data journalism. These hindrances include low and varied levels of quantitative literacy and math aversion among students, lack of time for upskilling and limited room in their courses for new material. The study found that at least nine Australian universities have semester-long units dedicated to data journalism and that at least a further nine are teaching it via some lectures and activities. Almost all respondents thought more should be done to incorporate data journalism into the curricula. This article lays a foundation for future exploration of how data journalism could be incorporated into journalism programmes where the staff requires upskilling

Modelling and Optimising of a Light-Weight Rockfall Catch Fence System

Rockfall catch fence is a mechanical barrier system that is used at the foot of cliffs to stop and retain falling rocks from reaching nearby infrastructures. A typical system comprises of a high tensile strength wire mesh that is anchored to the ground by rigid posts and strengthened to the lateral and upslope sides by anchoring tension cables. Additional components, such as shock absorbers, might be added to improve the system capacity to dissipate energy. This multi-component system characterises by geometrical complexity and high nonlinear response to impact loads. A light-weight catch fence system is a simple system that can be easily installed in a time efficient manner using manpower rather than heavy machinery, which makes it ideal for railways located in mountainous and difficult terrain regions where there is difficulty in accessing sites with limited workspaces and restricted installation times. However, this should be combined with a proper design to ensure that the system provides the required protection to impede falling rocks from reaching the train lines. In this paper, a parametric study based on finite element analysis is developed to optimise the design of a light-weight catch fence system that has an energy absorption capacity of up to 100 kJ