59 resultados para dihedral corner reflector
Resumo:
Community arts can take many forms, including murals, installations, festivals and performances. The work can be produced by artists solely, by artists working with community groups, or by community groups. Community arts can be on a grand-scale covering whole streets, parks or even towns, or small- scale, such as a mosaic in the corner of a play area. It can be extremely impacting and a permanent fixture, or fragile and small and designed to blow away in the wind. But, common to all these different forms of community arts are the criteria that community arts are made in, for and/or by, the local community.
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A travel article about the Aland Islands, Finland, that discusses the mix of Swedish, Finnish, and Russian cultural influences in the area. On the map, Finland seems to end in fragments. The gods have stomped their heels on the southwestern corner, and between the cities of Helsinki and Turku it is jagged, rocky islands that form the final landmarks...
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Biofuel produced by fast pyrolysis from biomass is a promising candidate. The heart of the system is a reactor which is directly or indirectly heated to approximately 500°C by exhaust gases from a combustor that burns pyrolysis gas and some of the by-product char. In most of the cases, external biomass heater is used as heating source of the system while internal electrical heating is recently implemented as source of reactor heating. However, this heating system causes biomass or other conventional forms of fuel consumption to produce renewable energy and contributes to environmental pollution. In order to overcome these, the feasibility of incorporating solar energy with fast pyrolysis has been investigated. The main advantages of solar reactor heating include renewable source of energy, comparatively simpler devices, and no environmental pollution. A lab scale pyrolysis setup has been examined along with 1.2 m diameter parabolic reflector concentrator that provides hot exhaust gas up to 162°C. The study shows that about 32.4% carbon dioxide (CO2) emissions and almost one-third portion of fuel cost are reduced by incorporating solar heating system. Successful implementation of this proposed solar assisted pyrolysis would open a prospective window of renewable energy.
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The mean shift tracker has achieved great success in visual object tracking due to its efficiency being nonparametric. However, it is still difficult for the tracker to handle scale changes of the object. In this paper, we associate a scale adaptive approach with the mean shift tracker. Firstly, the target in the current frame is located by the mean shift tracker. Then, a feature point matching procedure is employed to get the matched pairs of the feature point between target regions in the current frame and the previous frame. We employ FAST-9 corner detector and HOG descriptor for the feature matching. Finally, with the acquired matched pairs of the feature point, the affine transformation between target regions in the two frames is solved to obtain the current scale of the target. Experimental results show that the proposed tracker gives satisfying results when the scale of the target changes, with a good performance of efficiency.
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The mathematical model of a steadily propagating Saffman-Taylor finger in a Hele-Shaw channel has applications to two-dimensional interacting streamer discharges which are aligned in a periodic array. In the streamer context, the relevant regularisation on the interface is not provided by surface tension, but instead has been postulated to involve a mechanism equivalent to kinetic undercooling, which acts to penalise high velocities and prevent blow-up of the unregularised solution. Previous asymptotic results for the Hele-Shaw finger problem with kinetic undercooling suggest that for a given value of the kinetic undercooling parameter, there is a discrete set of possible finger shapes, each analytic at the nose and occupying a different fraction of the channel width. In the limit in which the kinetic undercooling parameter vanishes, the fraction for each family approaches 1/2, suggesting that this selection of 1/2 by kinetic undercooling is qualitatively similar to the well-known analogue with surface tension. We treat the numerical problem of computing these Saffman-Taylor fingers with kinetic undercooling, which turns out to be more subtle than the analogue with surface tension, since kinetic undercooling permits finger shapes which are corner-free but not analytic. We provide numerical evidence for the selection mechanism by setting up a problem with both kinetic undercooling and surface tension, and numerically taking the limit that the surface tension vanishes.
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The structures of the 1:1 co-crystalline adduct C8H6BrN3S . C7H5NO4 (I) and the salt C8H7BrN3S+ C7H3N2O7- (II) from the interaction of 5-(4-bromophenyl)-1,3,4-thiadiazol-2-amine with 4-nitrobenzoic acid and 3,5-dinitrosalicylic acid, respectively, have been determined. The primary inter-species association in both (I) and (II) is through duplex R2/2(8) (N-H...O/O-H...O) or (N-H...O/N-H...O) hydrogen bonds, respectively, giving heterodimers. In (II), these are close to planar [dihedral angles between the thiadiazole ring and the two phenyl rings are 2.1(3)deg. (intra) and 9.8(2)deg. (inter)], while in (I) these angles are 22.11(15) and 26.08(18)deg., respectively. In the crystal of (I), the heterodimers are extended into a one-dimensional chain along b through an amine N-...N(thiadiazole) hydrogen bond but in (II), a centrosymmetric cyclic heterotetramer structure is generated through N-H...O hydrogen bonds to phenol and nitro O-atom acceptors and features, together with the primary R2/2(8) interaction, conjoined R4/6(12), R2/1(6) and S(6) ring motifs. Also present in (I) are pi--pi interactions between thiadiazole rings [minimum ring centroid separation, 3.4624(16)deg.] as well as short Br...O(nitro) interactions in both (I) and (II) [3.296(3)A and 3.104(3)A, respectively].
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The research reported here addresses the problem of detecting and tracking independently moving objects from a moving observer in real-time, using corners as object tokens. Corners are detected using the Harris corner detector, and local image-plane constraints are employed to solve the correspondence problem. The approach relaxes the restrictive static-world assumption conventionally made, and is therefore capable of tracking independently moving and deformable objects. Tracking is performed without the use of any 3-dimensional motion model. The technique is novel in that, unlike traditional feature-tracking algorithms where feature detection and tracking is carried out over the entire image-plane, here it is restricted to those areas most likely to contain-meaningful image structure. Two distinct types of instantiation regions are identified, these being the “focus-of-expansion” region and “border” regions of the image-plane. The size and location of these regions are defined from a combination of odometry information and a limited knowledge of the operating scenario. The algorithms developed have been tested on real image sequences taken from typical driving scenarios. Implementation of the algorithm using T800 Transputers has shown that near-linear speedups are achievable, and that real-time operation is possible (half-video rate has been achieved using 30 processing elements).
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This thesis is concerned with two-dimensional free surface flows past semi-infinite surface-piercing bodies in a fluid of finite-depth. Throughout the study, it is assumed that the fluid in question is incompressible, and that the effects of viscosity and surface tension are negligible. The problems considered are physically important, since they can be used to model the flow of water near the bow or stern of a wide, blunt ship. Alternatively, the solutions can be interpreted as describing the flow into, or out of, a horizontal slot. In the past, all research conducted on this topic has been dedicated to the situation where the flow is irrotational. The results from such studies are extended here, by allowing the fluid to have constant vorticity throughout the flow domain. In addition, new results for irrotational flow are also presented. When studying the flow of a fluid past a surface-piercing body, it is important to stipulate in advance the nature of the free surface as it intersects the body. Three different possibilities are considered in this thesis. In the first of these possibilities, it is assumed that the free surface rises up and meets the body at a stagnation point. For this configuration, the nonlinear problem is solved numerically with the use of a boundary integral method in the physical plane. Here the semi-infinite body is assumed to be rectangular in shape, with a rounded corner. Supercritical solutions which satisfy the radiation condition are found for various values of the Froude number and the dimensionless vorticity. Subcritical solutions are also found; however these solutions violate the radiation condition and are characterised by a train of waves upstream. In the limit that the height of the body above the horizontal bottom vanishes, the flow approaches that due to a submerged line sink in a $90^\circ$ corner. This limiting problem is also examined as a special case. The second configuration considered in this thesis involves the free surface attaching smoothly to the front face of the rectangular shaped body. For this configuration, nonlinear solutions are computed using a similar numerical scheme to that used in the stagnant attachment case. It is found that these solution exist for all supercritical Froude numbers. The related problem of the cusp-like flow due to a submerged sink in a corner is also considered. Finally, the flow of a fluid emerging from beneath a semi-infinite flat plate is examined. Here the free surface is assumed to detach from the trailing edge of the plate horizontally. A linear problem is formulated under the assumption that the elevation of the plate is close to the undisturbed free surface level. This problem is solved exactly using the Wiener-Hopf technique, and subcritical solutions are found which are characterised by a train of sinusoidal waves in the far field. The nonlinear problem is also considered. Exact relations between certain parameters for supercritical flow are derived using conservation of mass and momentum arguments, and these are confirmed numerically. Nonlinear subcritical solutions are computed, and the results are compared to those predicted by the linear theory.
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In July 2014, Melbourne hosted the 20th International AIDS Conference. The event opened, paying tribute to the late Dutch HIV/AIDS researcher Professor Joep Lange, with his image projected onto a screen, with the accompanying quotation: ‘If we can bring a bottle of Coke to every corner of Africa, we should be able to also deliver antiretroviral drugs.’
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Steel columns in frame structure always carry heavy upcoming compressive forces. As a consequence, axial shortening becomes a common phenomenon in a multistoried steel structure. A 100 storied steel structure is analyzed in SAP2000 to study the magnitude overall effects of column shortening. It was found from the study that the maximum axial shortening occurs at the columns of top storey of the steel structure and at the columns of bottom storey, the axial deformation is negligible. The increasing rate of axial shortening is significant at the initial levels. However, at the upper levels, the amount of axial shortening in steel columns differs insignificantly. In the selected rigid frame structure, the axial shortening of adjacent steel columns is found to influence significantly the differential shortening of the structure. The consequent effect of differential shortening leads to develop excessive stress in the corner joints which ultimately hamper the normal behavior of the structural systems. The results are discussed elaborately in the paper.
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Based on protein molecular dynamics, we investigate the fractal properties of energy, pressure and volume time series using the multifractal detrended fluctuation analysis (MF-DFA) and the topological and fractal properties of their converted horizontal visibility graphs (HVGs). The energy parameters of protein dynamics we considered are bonded potential, angle potential, dihedral potential, improper potential, kinetic energy, Van der Waals potential, electrostatic potential, total energy and potential energy. The shape of the h(q)h(q) curves from MF-DFA indicates that these time series are multifractal. The numerical values of the exponent h(2)h(2) of MF-DFA show that the series of total energy and potential energy are non-stationary and anti-persistent; the other time series are stationary and persistent apart from series of pressure (with H≈0.5H≈0.5 indicating the absence of long-range correlation). The degree distributions of their converted HVGs show that these networks are exponential. The results of fractal analysis show that fractality exists in these converted HVGs. For each energy, pressure or volume parameter, it is found that the values of h(2)h(2) of MF-DFA on the time series, exponent λλ of the exponential degree distribution and fractal dimension dBdB of their converted HVGs do not change much for different proteins (indicating some universality). We also found that after taking average over all proteins, there is a linear relationship between 〈h(2)〉〈h(2)〉 (from MF-DFA on time series) and 〈dB〉〈dB〉 of the converted HVGs for different energy, pressure and volume.
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On arriving at the University of Queensland, I walked from where the taxi dropped me off towards the Great Court. As I walked I could see the carvings in the sandstone on the façade of the building in front of me. The carvings depict images of land, flora, fauna, settlers, and us. In the corner of my right sight of vision, I could see Mayne Hall. My mind flicked back in what was an instant to a time 30 plus years ago. I remember putting on some of my best clothes when my family would travel form the suburb of Inala to the Alumni book fair held in the Hall. We needed to act ‘discrete’ and like we were ‘meant to be there’. Members of my family would work hard to save money to buy the books that had far more substance than the books at our local community or school library. This was my first interaction with the University of Queensland. On the first day of Courting Blakness, I walked towards and then into the Great Court. I began to explore and engage with the artworks and allow them to engage with me. I was conscious of being in the University of Queensland as I had been on all my past visits. I was conscious of the public and the private aspects of the artworks along with the public observance and surveillance of the viewers of the artworks. The contradictions and struggles that Aboriginal and Torres Strait Islander people experience are everywhere when moving in spaces and places, including universities. They contain prevailing social, political and economic values in the same way that other places do. The symbols of place and space within universities are never neutral, and they can work to either marginalise and oppress Aboriginal and Torres Strait Islander people, or demonstrate that they are included and engaged. The artworks in the Great Court were involved in this matrix of mixed messages and the weaves of time contained the borders of the Court and within the minds of those present.
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Three-dimensional (3D) hierarchical nanoscale architectures comprised of building blocks, with specifically engineered morphologies, are expected to play important roles in the fabrication of 'next generation' microelectronic and optoelectronic devices due to their high surface-to-volume ratio as well as opto-electronic properties. Herein, a series of well-defined 3D hierarchical rutile TiO2 architectures (HRT) were successfully prepared using a facile hydrothermal method without any surfactant or template, simply by changing the concentration of hydrochloric acid used in the synthesis. The production of these materials provides, to the best of our knowledge, the first identified example of a ledgewise growth mechanism in a rutile TiO2 structure. Also for the first time, a Dye-sensitized Solar Cell (DSC) combining a HRT is reported in conjunction with a high-extinction-coefficient metal-free organic sensitizer (D149), achieving a conversion efficiency of 5.5%, which is superior to ones employing P25 (4.5%), comparable to state-of-the-art commercial transparent titania anatase paste (5.8%). Further to this, an overall conversion efficiency 8.6% was achieved when HRT was used as the light scattering layer, a considerable improvement over the commercial transparent/reflector titania anatase paste (7.6%), a significantly smaller gap in performance than has been seen previously.
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ABORIGINAL people in urbanised Australia experience violence on a daily basis. This violence ranges from the psychological (the covert hostility of the corner shop, the denial of the Aboriginality of fair-skinned or urban Blacks) through to the physical brutality of the criminal justice system. For Aboriginal women and children this daily violence is not only public but also has a private, B1ack-on-B1ack dimension. The Aboriginal home may be some refuge from the slights of white Australia but this is cold comfort to women for whom being 'flogged up' by their partners is so ordinary an event as to be unremarkable.