Past Industrial and Interdisciplinary Workshops

24 January 2014
10:00
Tim Aitken
Abstract
<!-- PRE { direction: ltr; color: rgb(0, 0, 10); }PRE.cjk { font-family: "Droid Sans Fallback",monospace; }PRE.ctl { font-family: "Lohit Hindi",monospace; }P { margin-bottom: 0.21cm; direction: ltr; color: rgb(0, 0, 10); }P.western { font-family: "Times New Roman",serif; font-size: 12pt; }P.cjk { font-family: "Droid Sans Fallback"; font-size: 12pt; }P.ctl { font-family: "Lohit Hindi"; font-size: 12pt; }A:link { } --> <pre class="western"><span style="font-family: Times New Roman,serif;"><span style="font-size: x-small;">The problem is based on real time computation for 4D (3D+time) trajectory planning for unmanned vehicles (UVs). The ability to quickly predict a 4D trajectory/path enables safe, flexible, efficient use of UVs in a collaborative space is a key objective for autonomous mission and task management. </span></span> <span style="font-family: Times New Roman,serif;"><span style="font-size: x-small;">The problem/topic proposal will consist of 3 challenges: </span></span><br /><span style="font-family: Times New Roman,serif;"><span style="font-size: x-small;">1. A single UV 4D path planning problem.</span></span><br /><span style="font-family: Times New Roman,serif;"><span style="font-size: x-small;">2. Multi UV 4D path planning sharing the same space and time.</span></span><br /><span style="font-family: Times New Roman,serif;"><span style="font-size: x-small;">3. Assignment of simultaneous tasks for multiple UVs based on the 4D path finding solution.</span></span>
  • Industrial and Interdisciplinary Workshops
15 November 2013
10:00
Philip Pidsley, Thales Underwater Systems
Abstract
A projectile travelling supersonically in air creates a shock wave in the shape of a cone, with the projectile at the tip of the Mach cone. When the projectile travels over an array of microphones the shock wave is detected with different times of arrival at each microphone. Given measurements of the times of arrival, we are trying to calculate the azimuth direction of travel of the projectile. We have found a solution when the speed of the projectile is known. However the solution is ambiguous, and can take one of two possible values. Therefore we are seeking a new mathematical approach to resolve the ambiguity and thus find the azimuth direction of travel.
  • Industrial and Interdisciplinary Workshops
8 November 2013
10:00
Philip Roberts (Sharp)
Abstract
<p> <div class="O"><span>Sharp Labs of Europe is interested in understanding the kinetics of ice on the inside of a rectangular channel through which water is flowing.&nbsp;The channel can be considered to be a long hole milled into a metal block. The block is maintained at a fixed temperature (&lt;0°C).&nbsp;Nucleation is provided by ultrasonication.&nbsp;We are interested in:</span></div> <div class="O"><span>- The position along the channel that ice begins to form / block the channel.&nbsp;</span></div> <div class="O"><span>- The ice profile (thickness) along the length of the channel as it grows.&nbsp;</span></div> <div class="O"><span>- The effect of channel size and profile (straight, fan shaped etc) on the ice profile.</span></div> <div class="O"><span>- Effect of flow speed on ice formation.</span></div> </p>
  • Industrial and Interdisciplinary Workshops
14 June 2013
09:45
to
11:00
TBA
Abstract
Note early start to avoid a clash with the OCCAM group meeting.
  • Industrial and Interdisciplinary Workshops
7 June 2013
10:00
Abstract
Collective behaviours of coupled linear or nonlinear resonators have been of interest to engineers as well as mathematician for a long time. In this presentation, using the example of coupled resonant nano-sensors (which leads to a Linear pencil with a Jacobian matrix), I will show how previously feared and often avoided coupling between nano-devices along with their weak nonlinear behaviour can be used with inverse eigenvalue analysis to design multiple-input-single-output nano-sensors. We are using these matrices in designing micro/Nano electromechanical systems, particularly resonant sensors capable for measuring very small mass for use as environmental as well as biomedical monitors. With improvement in fabrication technology, we can design and build several such sensors on one substrate. However, this leads to challenges in interfacing them as well as introduces undesired parasitic coupling. More importantly, increased nonlinearity is being observed as these sensors reduce in size. However, this also presents an opportunity to experimentally study chains or matrices of coupled linear and/or nonlinear structures to develop new sensing modalities as well as to experimentally verify theoretically or numerically predicted results. The challenge for us is now to identify sensing modalities with chain of linear or nonlinear resonators coupled either linearly or nonlinearly. We are currently exploring chains of Duffing resonators, van der Pol oscillators as well as FPU type lattices.
  • Industrial and Interdisciplinary Workshops
31 May 2013
10:00
to
11:15
Abstract

In order to reduce cost, the MOD are attempting to reduce the number of array types fitted to their assets. There is also a requirement for the arrays to increase their frequency coverage. A wide bandwidth capability is thus needed from a single array. The need for high sensitivity and comparatively high frequencies of operation has led to the view that 1 3 composites are suitable hydrophones for this purpose. These hydrophones are used widely in ultra-sonics, but are not generally used down to the frequency of the new arrays.

Experimental work using a single hydrophone (small in terms of wavelengths) has shown that the sensitivity drops significantly as the frequency approaches the bottom of the required band, and then recovers as the frequency reduces further. Complex computer modelling appears to suggest the loss in sensitivity is due to a "lateral mode" where the hydrophone "breathes" in and out. In order to engineer a solution, the mechanics of the cause of this problem and the associated parameters of the materials need to be identified (e.g. is changing the 1 3 filler material the best option?). In order to achieve this understanding, a mathematical model of the 1 3 composite hydrophone (ceramic pegs and filler) is required that can be used to explain why the hydrophone changes from the simple compression and expansion in the direction of travel of the wave front to a lateral "breathing" mode.

More details available from gower@maths.ox.ac.uk

  • Industrial and Interdisciplinary Workshops
24 May 2013
10:00
to
11:15
Richard Todd
Abstract
“Flash sintering” is a process reported by R Raj and co-workers in which very rapid densification of a ceramic powder compact is achieved by the passage of an electrical current through the specimen. Full density can be achieved in a few seconds (sintering normally takes several hours) and at furnace temperatures several hundred Kelvin below the temperatures required with conventional sintering. The name of the process comes from a runaway power spike that is observed at the point of sintering. Although it is acknowledged by Raj that Joule heating plays a role in the process, he and his co-authors claim that this is of minor importance and that entirely new physical effects must also be involved. However, the existence and possible relevance of these other effects of the electric field/current remains controversial. The aim of this workshop is to introduce the subject and to stimulate discussion of how mathematics could shed light on some the factors that are difficult to measure and understand experimentally.
  • Industrial and Interdisciplinary Workshops

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