1,196 research outputs found

    Methodology for evaluating the safety level of current accepted design solutions for limiting fire spread between buildings

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    External fire spread between buildings is internationally considered as a major concern for buildings in dense urban environments. While design guidelines differ between countries, the fundamental methods currently used for limiting the risk of fire spread between buildings are generally limited to specifying the minimum required separation distance for a given unprotected façade area, or conversely, limiting the maximum allowable unprotected façade area for a given separation distance. The safety level associated with the current design guidelines is however unknown, making the implementation of innovative, safer and more cost-effective design solutions difficult. In order to assess the safety target implicitly incorporated in currently accepted design solutions, a methodology is developed for evaluating the annual probability of reaching unacceptable radiation intensities at the opposite façade. As a case study, the methodology is applied to a design which is in agreement with the current UK requirements specified in BR 187. This case study exposes inconsistencies in the current design guidelines, indicating the need for developing explicit safety targets

    Inter-CubeSat Communication with V-band "Bull's eye" antenna

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    We present the study of a simple communication scenario between two CubeSats using a V-band “Bull's eye” antenna that we designed for this purpose. The return loss of the antenna has a -10dB bandwidth of 0.7 GHz and a gain of 15.4dBi at 60 GHz. Moreover, the low-profile shape makes it easily integrable in a CubeSat chassis. The communication scenario study shows that, using 0.01W VubiQ modules and V-band “Bull’s eye” antennas, CubeSats can efficiently transmit data within a 500 MHz bandwidth and with a 10-6 BER while being separated by up to 98m, under ideal conditions, or 50m under worst case operating conditions (5° pointing misalignment in E- and H-plane of the antenna, and 5° polarisation misalignment)

    An internet of laboratory things

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    By creating “an Internet of Laboratory Things” we have built a blend of real and virtual laboratory spaces that enables students to gain practical skills necessary for their professional science and engineering careers. All our students are distance learners. This provides them by default with the proving ground needed to develop their skills in remotely operating equipment, and collaborating with peers despite not being co-located. Our laboratories accommodate state of the art research grade equipment, as well as large-class sets of off-the-shelf work stations and bespoke teaching apparatus. Distance to the student is no object and the facilities are open all hours. This approach is essential for STEM qualifications requiring development of practical skills, with higher efficiency and greater accessibility than achievable in a solely residential programme

    Experience With Remote Laboratories For On-Campus Engineering Degrees

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    Simplified model of interconnect layers under a spiral inductor

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    We demonstrate the feasibility of using effective medium theory to reduce the computational complexity of full-wave models of inductors that are placed over interconnects. Placing inductors over interconnects is one way that designers can tackle the problem of reducing overall chip size, however this has heretofore been a difficult option to evaluate because of the prohibitive memory requirements and run times for detailed simulations of the inductor. Here we replace the interconnects with a homogeneous equivalent layer that mimics their impact on the inductor to within 2% error, but reducing runtime and memory use by 90% or more

    Performance analysis of an orbital angular momentum multiplexed amplify-and-forward radio relay chain with inter-modal crosstalk

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    The end-to-end spectral efficiency and bit error rate (BER) of an amplify-and-forward (AF) radio relay chain employing orbital angular momentum (OAM) multiplexing is presented. The inherent divergence of a beam carrying OAM is overcome by means of a lens. Modelled and measured inter-modal crosstalk levels are incorporated into the analysis. The results show that an end-to-end spectral efficiency of up to 8 bits s−1 Hz−1 is achievable using four OAM modes to multiplex four parallel data streams over 20 hops, provided that the detrimental effects of inter-modal crosstalk are mitigated. The spectral efficiency is expected to scale further by using more OAM modes. The BER profile along the relay chain is analysed for each of the four OAM modes

    Syntheses of some silicate mineral structures containing MnÂłâș ;Groundwater requiring protective landscaping\ua0: model trials at Dalrymple, North Queensland ;\ua0Natural supply of phosphorus from basalt controlled by rejuvenated landscapes along the Burdekin River, Queensland

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    Contents1. Syntheses of some silicate mineral structures containing Mn3+D.J. DRYSDALE ---\ua0P.1-52. Groundwater requiring protective landscaping: model trials at Dalrymple, North QueenslandE.J. HEIDECKER ---\ua0P.6-183. Natural supply of phosphorus from basalt controlled by rejuvenated landscapes along the Burdekin River, QueenslandE.J. HEIDECKER ---\ua0P.19-2

    Possibilities of Fabricating Copper-based RFID Tags with Photonic-sintered Inkjet Printing and Thermal Transfer Printing

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    This letter studies the possibilities of manufacturing copper-based passive UHF RFID tags using inkjet and thermal printing on two substrate materials, polyimide (Kapton) and a polyester based substrate (Flexcon THERMLfilm). Both printing methods are tested to fabricate different tag designs, and the performance of successfully printed tags is evaluated using wireless measurements. Measurement results show that both the printing methods, while using copper material, can be used to effectively fabricate passive UHF RFID tag antennas on selected substrates

    V-band Bull's eye antenna for multiple discretely steerable beams

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    We present a new approach to designing V-band Bull’s eye antenna so as to produce multiple beams, which are either fixed or discretely steerable. Bull’s eye antennas comprise concentric rings around a subwavelength aperture. Beam deflection is accomplished by adjusting the effective spacing of the rings, which we explain in terms of the coupling angle to free space and surface waves. We show that multiple beams can be obtained from a single antenna, with the deflection of each beam being controlled independently by the relevant portion of the ring pattern. We demonstrate the principle through rigorous full-wave simulations of two-beam antennas with symmetrical and asymmetrical shifts, and give experimental results for a prototype milled in aluminium, with two separate fixed beams each deflected 16° to either side of the broadside. We also propose means to obtain up to six different beam arrangements during operation by mechanically rotating a plate containing a special six-sector ring pattern. Our simulated example gives three patterns, a single broadside beam or two beams each deflected by 8° or 15°. The radiation efficiency of the antenna is 97%, and the gain of a single undeflected beam is 18.1dBi
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