Flexural Wrinkling Behaviour of Lightly Profiled Sandwich Panels

In Australia, sandwich panels are commonly made of flat or lightly profiled steel faces and expanded polystyrene foam cores. Flexural wrinkling is often the governing criterion in the design of these panels. The use of lightly profiled faces is expected to increase the flexural wrinkling stress considerably whereas the presence of joints between the polystyrene foam slabs in the transverse direction introduces a reduction to the flexural wrinkling stress. Therefore a series of full scale experiments and finite element analyses were conducted to evaluate the effects of lightly profiled faces and transverse joints on the flexural wrinkling stress of panels subjected to a lateral pressure loading. This paper presents the details of this investigation, the results and comparison with available theoretical and design solutions

Modelling the influence of the process inputs on the removal of surface contaminants from Ti-6Al-4V linear friction welds

The linear friction welding (LFW) process is finding increasing interest from industry for the fabrication of near-net-shape, titanium alloy Ti–6Al–4V, aerospace components. Currently, the removal of surface contaminants, such as oxides and foreign particles, from the weld interface into the flash is not fully understood. To address this problem, two-dimensional (2D) computational models were developed using the finite element analysis (FEA) software DEFORM and validated with experiments. The key findings showed that the welds made with higher applied forces required less burn-off to completely remove the surface contaminants from the interface into the flash; the interface temperature increased as the applied force was decreased or the rubbing velocity increased; and the boundary temperature between the rapid flash formation and negligible material flow was approximately 970 °C. An understanding of these phenomena is of particular interest for the industrialisation of near-net-shape titanium alloy aerospace components.EPSRC, Boeing Company, Welding Institut

The catalysts and constraints of castle-building in Suffolk c.1066-1200.

Twenty-seven Suffolk castles were built between 1066 and 1200. This thesis summarises the modern multi-disciplinary surveys of six of them, with the objective of identifying their location, morphology, form and function. The majority of Suffolk castles were built between the late 11th and mid-H-century and reached their largest number during the civil wars cA 135-54. However, a few remained operational after c.1200 and those that did are characterised as either royal or baronial caput castles. Moreover, almost all Suffolk castles were originally earth and timber, whereas the surviving examples were rebuilt in stone before c.1300. Therefore, those castles that survived beyond or were established after c.1200 are unrepresentative. Instead this thesis focuses on the period 1066 to 1200, when the more common sub-baronial, earth and timber Suffolk castles were evidenced. Chapter one identifies the key issues. Chapter two critiques each of the current models in castle studies before rejecting them in favour of a modified Annates model. Chapter three identifies the constraints of the tongue duree, identified as the environmental factors, defined as the climate, topography, geology, hydrology and timber supply in the vicinity of the castle. Chapter four identifies societal constraints, which are sub-divided into structural, social and cultural, and focuses on the Abbey of St Edmund's, its cult, viceroyship, ecclesiastical autonomy and barony, its relationship with the new elite and how it influenced castle building. Chapter five focuses on three of the six surveyed castle earthworks to establish the evenement level of the model, which identifies the castle building agents and the specific historical and political context in which these castles were built. Chapter six brings the different sources and levels of data together to offer a new model, a more nuanced definition of a castle and a comprehensive assessment of the conflicting demands of the catalysts and constraints operating upon the construction of castles in Suffolk. In this it is supported by over two hundred figures and plans, numerous tables, a comprehensive set of appendices and an extensive bibliography

Managing wild oat in tame oat through the seeding date and seeding rate of tame oat

Non-Peer Reviewe

Modelling of the workpiece geometry effects on Ti–6Al–4V linear friction welds

Linear friction welding (LFW) is a solid-state joining process that is finding increasing interest from industry for the fabrication of titanium alloy (Ti–6Al–4V) preforms. Currently, the effects of the workpiece geometry on the thermal fields, material flow and interface contaminant removal during processing are not fully understood. To address this problem, two-dimensional (2D) computational models were developed using the finite element analysis (FEA) software DEFORM and validated with experiments. A key finding was that the width of the workpieces in the direction of oscillation (in-plane width) had a much greater effect on the experimental weld outputs than the cross-sectional area. According to the validated models, a decrease of the in-plane width increased the burn-off rate whilst decreasing the interface temperature, TMAZ thickness and the burn-off required to remove the interface contaminants from the weld into the flash. Furthermore, the experimental weld interface consisted of a Widmanstätten microstructure, which became finer as the in-plane width was reduced. These findings have significant, practical benefits and may aid industrialisation of the LFW process.The authors would like to thank the Engineering and Physical Sciences Research Council (EPSRC), The Boeing Company and The Welding Institute (TWI) for funding the research presented in this paper

Zero-minimum tillage seeding and fertilizer placement techniques for zero-tillage

Non-Peer ReviewedPreliminary results from the field evaluation of zero and minimum tillage seeding machines, as well as fertilizer placement techniques for zero-tillage are presented. Narrow hoe opener (Noble 2000), conventional double-disc (Haybuster 1206), as well as two modified double-disc press drills have been compared for their seeding performance and effects on crop yields in a continuous zero-till wheat test. Further, an air-seeder, a discer and a conventional hoe press-drill have been field evaluated both on cultivated fallow and stubble situations. Deep banding and side banding (approximately 2.5 cm from seed) of fertilizer using both disc and hoe press-drills have been compared to seed-placed fertilizer application

Tablet PCs in schools: Case study report: A report for Becta by the Open University

The publication provides an analysis of twelve case studies involving schools in England that were using Tablet PCs. The analysis is complemented by brief individual reports describing aspects of how each of these schools was using Tablet PCs

The Jefferson Lab Frozen Spin Target

A frozen spin polarized target, constructed at Jefferson Lab for use inside a large acceptance spectrometer, is described. The target has been utilized for photoproduction measurements with polarized tagged photons of both longitudinal and circular polarization. Protons in TEMPO-doped butanol were dynamically polarized to approximately 90% outside the spectrometer at 5 T and 200--300 mK. Photoproduction data were acquired with the target inside the spectrometer at a frozen-spin temperature of approximately 30 mK with the polarization maintained by a thin, superconducting coil installed inside the target cryostat. A 0.56 T solenoid was used for longitudinal target polarization and a 0.50 T dipole for transverse polarization. Spin-lattice relaxation times as high as 4000 hours were observed. We also report polarization results for deuterated propanediol doped with the trityl radical OX063.Comment: 11 pages, 12 figures, preprint submitted to Nuclear Instruments and Methods in Physics Research, Section