A Mid-Infrared Galaxy Atlas (MIGA)

A mid-infrared atlas of part of the Galactic plane ($75^\circ < l < 148^\circ, b = \pm6^\circ$) has been constructed using HIRES processed infrared data to provide a mid-infrared data set for the Canadian Galactic Plane Survey (CGPS). The addition of this data set to the CGPS will enable the study of the emission from the smallest components of interstellar dust at an angular resolution comparable to that of the radio, millimetre, and far-infrared data in the CGPS. The Mid-Infrared Galaxy Atlas (MIGA) is a mid-infrared (12 $\mu$m and 25 $\mu$m) counterpart to the far-infrared IRAS Galaxy Atlas (IGA), and consists of resolution enhanced ($\sim 0.5'$ resolution) HIRES images along with ancillary maps. This paper describes the processing and characteristics of the atlas, the cross-beam simulation technique used to obtain high-resolution ratio maps, and future plans to extend both the IGA and MIGA.Comment: 38 pages (including 15 tables), 13 figures (8 dithered GIF and 5 EPS). Submitted to Astrophysical Journal Supplement Series. A preprint with higher resolution figures is available at http://www.cita.utoronto.ca/~kerton/publications.htm

Structural studies of titanyl and zirconyl sulphate hydrates

The aim of this thesis was to use a combination of computer simulations and experimental methods to gain insight into the unknown structure of the material titanyl sulphate dihydrate, TiOSO4*2H2O.Samples of TiOSO4*2H2O, along with TiOSO4*H2O, were produced and analysed using X-ray and neutron diffraction at both laboratory and synchrotron facilities. Both ex-situ and in-situ experiments were performed in order to analyse both the structure and growth of the crystals. The diffraction data resulting from these experiments was then used in various structure determination programs. A unit cell was able to be determined from the synchrotron X-ray diffraction patterns, and the first neutron diffraction pattern of a TiOSO4*2D2O sample was produced. In-situ synchrotron X-ray diffraction studies showed that the formation of the crystals followed a single step process, and indicated the possibility of meta-stable phases being present in the sample.In parallel with the experimental studies, computer modelling was used to develop and create candidate TiOSO4*2H2O structures. Initially both forcefield and first principles techniques were validated against a series of test cases. These included the first such calculations for the TiOSO4 and TiOSO4*H2O structures. The candidate structures of TiOSO4*2H2O thus produced were then used as input into the structural determination step.Structure determination was attempted with multiple approaches, using the determined unit cell and a variety of space group settings. Despite a thorough treatment and validation of the method using the diffraction data and known structure of TiOSO4*H2O, the structure was unable to be solved. However, structural motifs consistent with a layered, needle-like morphology, as observed in experimental studies, were commonly found to be present in solutions offered by these approaches. Future use of techniques such as the substitution of isotopic titanium in neutron diffraction may provide enough information to more accurately determine atomic positions

A computationally-efficient numerical model to characterize the noise behavior of metal-framed walls

Architects, designers, and engineers are making great efforts to design acoustically-efficient metal-framed walls, minimizing acoustic bridging. Therefore, efficient simulation models to predict the acoustic insulation complying with ISO 10140 are needed at a design stage. In order to achieve this, a numerical model consisting of two fluid-filled reverberation chambers, partitioned using a metal-framed wall, is to be simulated at one-third-octaves. This produces a large simulation model consisting of several millions of nodes and elements. Therefore, efficient meshing procedures are necessary to obtain better solution times and to effectively utilise computational resources. Such models should also demonstrate effective Fluid-Structure Interaction (FSI) along with acoustic-fluid coupling to simulate a realistic scenario. In this contribution, the development of a finite element frequency-dependent mesh model that can characterize the sound insulation of metal-framed walls is presented. Preliminary results on the application of the proposed model to study the geometric contribution of stud frames on the overall acoustic performance of metal-framed walls are also presented. It is considered that the presented numerical model can be used to effectively visualize the noise behaviour of advanced materials and multi-material structures

Numerical modelling of the lobes of radio galaxies in cluster environments – III. Powerful relativistic and non-relativistic jets

We present results from two suites of simulations of powerful radio galaxies in poor cluster environments, with a focus on the formation and evolution of the radio lobes. One suite of models uses relativistic hydrodynamics and the other relativistic magnetohydrodynamics; both are set up to cover a range of jet powers and velocities. The dynamics of the lobes are shown to be in good agreement with analytical models and with previous numerical models, confirming in the relativistic regime that the observed widths of radio lobes may be explained if they are driven by very light jets. The ratio of energy stored in the radio lobes to that put into the intracluster gas is seen to be the same regardless of jet power, jet velocity or simulation type, suggesting that we have a robust understanding of the work done on the ambient gas by this type of radio source. For the most powerful jets, we at times find magnetic field amplification by up to a factor of 2 in energy, but mostly the magnetic energy in the lobes is consistent with the magnetic energy injected. We confirm our earlier result that for jets with a toroidally injected magnetic field, the field in the lobes is predominantly aligned with the jet axis once the lobes are well developed, and that this leads to radio flux anisotropies of up to a factor of about two for mature sources. We reproduce the relationship between 151 MHz luminosity and jet power determined analytically in the literature.Peer reviewe

Tissue Inhibitor of Metalloproteinase–3 (TIMP-3) induces FAS dependent apoptosis in human vascular smooth muscle cells

Over expression of Tissue Inhibitor of Metalloproteinases-3 (TIMP-3) in vascular smooth muscle cells (VSMCs) induces apoptosis and reduces neointima formation occurring after saphenous vein interposition grafting or coronary stenting. In studies to address the mechanism of TIMP-3-driven apoptosis in human VSMCs we find that TIMP-3 increased activation of caspase-8 and apoptosis was inhibited by expression of Cytokine response modifier A (CrmA) and dominant negative FAS-Associated protein with Death Domain (FADD). TIMP-3 induced apoptosis did not cause mitochondrial depolarisation, increase activation of caspase-9 and was not inhibited by over-expression of B-cell Lymphoma 2 (Bcl2), indicating a mitochondrial independent/type-I death receptor pathway. TIMP-3 increased levels of the First Apoptosis Signal receptor (FAS) and depletion of FAS with shRNA showed TIMP-3-induced apoptosis was FAS dependent. TIMP-3 induced formation of the Death-Inducing Signalling Complex (DISC), as detected by immunoprecipitation and by immunofluorescence. Cellular-FADD-like IL-1 converting enzyme-Like Inhibitory Protein (c-FLIP) localised with FAS at the cell periphery in the absence of TIMP-3 and this localisation was lost on TIMP-3 expression with c-FLIP adopting a perinuclear localisation. Although TIMP-3 inhibited FAS shedding, this did not increase total surface levels of FAS but instead increased FAS levels within localised regions at the cell surface. A Disintegrin And Metalloproteinase 17 (ADAM17) is inhibited by TIMP-3 and depletion of ADAM17 with shRNA significantly decreased FAS shedding. However ADAM17 depletion did not induce apoptosis or replicate the effects of TIMP-3 by increasing localised clustering of cell surface FAS. ADAM17-depleted cells could activate caspase-3 when expressing levels of TIMP-3 that were otherwise sub-apoptotic, suggesting a partial role for ADAM17 mediated ectodomain shedding in TIMP-3 mediated apoptosis. We conclude that TIMP-3 induced apoptosis in VSMCs is highly dependent on FAS and is associated with changes in FAS and c-FLIP localisation, but is not solely dependent on shedding of the FAS ectodomain

Investigation into the numerical model behaviour of Belleville washers in cold roll forming

With the steadily increase in demand for roll formed products due to their application for fields such as automotive, construction, architecture, etc., roll forming companies are challenge with rising customer demands. Companies are struggling to bring a product through from design to manufacture at improved rates, whilst achieving tighter tolerances. The roll forming process may also induce undesirable forming defects such as twist, distortion and straightness problems.Traditionally these issues would be resolved through an empirical approach which heavily relies on the designer's expertise and intuition. This approach can increase undesired development costs due to materials wasted and time delayed. Over the years, numerical simulations have been deployed to try and geometrically validate these defects and ultimately reduce the development phase of a product. The designer has the capability to virtually investigate changes in specific parameters without the risk of expensive tooling costs. The industry partner of this project, Hadley Group, Birmingham, implement Belleville washers into the roll tool configuration. The purpose of these washers is to apply pressure to the strip during roll forming in order to drive material through each forming station. They are also used to adjust the gap between the top and bottom forming rolls, since the incoming material gauge can vary by the nominal tolerance values from coil to coil. For the purpose of this paper, an investigation is carried out focusing on an individual parameter within the finite element analysis (FEA) of the cold roll forming process, i.e. the 'unknown' spring acting on the top roll during the forming process due to the implementation of Belleville washers in the pillar set up. The work explained in this paper shows the eects of the pressure applied to the forming process on the geometric attributes of the section being formed. The outcome will determine the viability of this parameter, which may ultimately require the numerical design methodology of roll formed products to be amended accordingly

Design optimisation for cold rolled steel beam sections with complex stiffeners considering cold working effects

This paper presents the analysis and design optimization of the cold rolled steel sections for flexural strength considering the effect of cold working exerted on the section during the roll forming process. The sections included channel and zed shapes with complex longitudinal web and flange stiffeners. Nonlinear Finite Element (FE) modelling was developed to model the flexural strength of the channel and zed beams and validated against the four-point bending experiments for these sections. The material properties of steel at the section’s flat parts, corners, and stiffener bends were obtained from tensile tests and were incorporated into the FE simulations to account for the true material properties at these regions. The section strength was then optimized using FE modelling results based on the Design of Experiments (DOE) and response surface methodology. Optimal designs for the channel and zed sections with maximum strength in distortional buckling could be obtained while changing the stiffeners’ position, shape, sizes, and considering material properties at section corners and stiffener bends. It revealed that, the optimal designs provided up to 13% and 17% increase in flexural strength for the channel and zed sections, respectively; however, when the true material properties at the section corner and the stiffener’s bend regions was included, the increase in flexural strength increased up to 20% and 23%, respectively

Validation of a finite element model of the cold roll forming process on the basis of 3D geometric accuracy

Cold roll forming is an incremental sheet metal forming process used to supply products to numerous industries such as automotive, architecture and construction, etc. In recent years there has been an increase in the demand by customers for high value products, through the forming of high strength materials, or complex profiles. Such demands increase the challenges faced by the tooling designer to bring a successful product through from design to manufacture, on time and within specification. Finite element (FE) simulations are increasingly applied in industry due to the desired advantage of reducing design iterations by allowing the designer to investigate the effects of parameter changes, without the risk of expensive tooling costs. Some successful validation of the numerical modelling of the cold roll forming process can be found in literature, in particular when analysing the strain distribution across the material or comparing the final rolled profile geometry. However, cold roll forming is a continuous process and no one has published work on the measurement of the profile on a pass to pass basis, in particular, the three dimensional geometry of the profile. Experimental trials were carried out to obtain a 3D point cloud model of the top surface of a roll formed section. This investigation aimed to quantify how accurate FE simulation may be in relation to physical data

Design of new cold rolled purlins by experimental testing and Direct Strength Method

New cold roll formed channel and zed sections for purlins, namely UltraBEAM™2 and UltraZED™2, have been developed by Hadley Industries plc using a combined approach of experimental testing, finite element modelling and optimisation techniques. The new sections have improved strength to weight ratio by increasing the section's strength through the use of stiffeners in the section webs. The European standard, Eurocode 3 [1], uses the traditional Effective Width Method to determine the strength of a cold formed steel member. However, the design of the new sections UltraBEAM™2 and UltraZED™2 using this method is very complicated in calculating the effective section properties as these sections contain complex folded-in stiffeners. In addition, the incorporation of competing buckling modes such as distortional buckling of these sections can be difficult to analyse. To overcome difficulties of using Eurocode 3 or such a standard with the Effective Width Method for determining the strength of these sections, the Direct Strength Method is adopted in this paper. Four-point beam bending tests were carried out to determine the buckling and ultimate bending capacities of the UltraBEAM™2 and UltraZED™2 sections. Results from both experimental testing and Finite Element analysis were initially used as validation for the design using the Direct Strength Method. The Direct Strength Method's results were then compared with the experimental test results for a broader data in which the UltraBEAM™2 and UltraZED™2 sections had a range of different width-to-thickness ratios. It showed an excellent agreement between test and Direct Strength design values suggesting that the Direct Strength Method is a powerful tool for the design and optimisation of the new cold roll formed channel and zed purlins.N/