Mathematical Scienceshttp://hdl.handle.net/10468/882017-10-23T22:33:30Z2017-10-23T22:33:30ZThe influence of process parameters on the physical characteristics of ceramic microneedles, evaluated using a factorial designCarracedo-Taboada, MartaO'Sullivan, KathleenMcAuliffe, Michael A. P.Vucen, SonjaO'Sullivan, Carolinehttp://hdl.handle.net/10468/48512017-10-10T11:00:39Z2017-10-05T00:00:00ZThe influence of process parameters on the physical characteristics of ceramic microneedles, evaluated using a factorial design
Carracedo-Taboada, Marta; O'Sullivan, Kathleen; McAuliffe, Michael A. P.; Vucen, Sonja; O'Sullivan, Caroline
Salguero, Jorge; Ares, Enrique
The paper presents the application of the factorial Design of Experiments (DoE) to evaluate the influence of process parameters on the physical characteristics of ceramic microneedles (CMN). In this study, an understanding of the fabrication process was achieved by performing a DoE based on varying two levels of five parameters. Statistical analyses were performed on the data to investigate whether the process parameters have a significant effect on the production of a patch of 25 microneedles (MN) with sharp tips. The study showed that four out of five main effects as well as an interaction between two parameters were significant.
2017-10-05T00:00:00ZThe constrained optimisation of small linear arrays of heaving point absorbers. Part I: The influence of spacingMcGuinness, Justin P. L.Thomas, Garethhttp://hdl.handle.net/10468/48392017-10-05T18:00:22Z2017-07-18T00:00:00ZThe constrained optimisation of small linear arrays of heaving point absorbers. Part I: The influence of spacing
McGuinness, Justin P. L.; Thomas, Gareth
This paper describes the optimisation of small arrays of Wave Energy Converters (WECs) of point absorber type. The WECs are spherical in shape and operate in heave alone and a linear array of five devices is considered. Previous work is extended by considering the constrained performance of the array members, where an uaniper limit on WEC displacements is enforced. Two opimisations are performed. In each case, the objective function is defined as the mean of the averaged interaction factor ovehe non-dimensional length of the array. The first considers the array layout fixed at a geometry previously identified as optimal in an unconstrained regime and optimises the displacements of the WECs subject to constraints. The second allows both the WEC positions and displacements to vary as optimisation variables. It is shown that the optimal layout of the constrained arrays is different from the unconstrained case. Applying constrained motions results in optimal layouts that are more separated, with less grouping of WECs and this will have practical considerations. The effect of the constraints varies depending on the incident wave angle. In some cases, performance is reduced drastically and stability of performance is improved, while in other cases there is a degradation of performance. Thus, a trade-off between performance and stability of performance is seen when displacement constraints are applied.
2017-07-18T00:00:00ZModeling cortical spreading depression induced by the hyperactivity of interneuronsDesroches, MathieuFaugeras, OlivierKrupa, MartinMantegazza, Massimohttp://hdl.handle.net/10468/40182017-05-24T18:00:57Z2017-05-10T00:00:00ZModeling cortical spreading depression induced by the hyperactivity of interneurons
Desroches, Mathieu; Faugeras, Olivier; Krupa, Martin; Mantegazza, Massimo
Cortical spreading depression (CSD) is a wave of transient intense neuronal firing leading to a long lasting depolarization block of neuronal activity. It is a proposed pathological mechanism of migraine with aura. Some molecular/cellular mechanisms of migraine with aura and of CSD have been identified studying a rare mendelian form: familial hemiplegic migraine (FHM). FHM type 1 & 2 are caused by mutations of the CaV2.1 Ca2+ channel and the glial Na+ / K+ pump, respectively, leading to facilitation of CSD in mouse models mainly because of increased glutamatergic transmission/extracellular glutamate build-up. FHM type 3 mutations of the SCN1A gene, coding for the voltage gated sodium channel NaV1.1, cause gain of function of the channel and hyperexcitability of GABAergic interneurons. This leads to the counterintuitive hypothesis that intense firing of interneurons can cause CSD ignition. To test this hypothesis in silico, we developed a computational model of an E-I pair (a pyramidal cell and an interneuron), in which the coupling between the cells in not just synaptic, but takes into account also the effects of the accumulation of extracellular potassium caused by the activity of the neurons and of the synapses. In the context of this model, we show that the intense firing of the interneuron can lead to CSD. We have investigated the effect of various biophysical parameters on the transition to CSD, including the levels of glutamate or GABA, frequency of the interneuron firing and the efficacy of the KCC2 co-transporter. The key element for CSD ignition in our model was the frequency of interneuron firing and the related accumulation of extracellular potassium, which induced a depolarization block of the pyramidal cell. Our model can be used to study other types of activities in microcircuits and of couplings between excitatory and inhibitory neurons.
2017-05-10T00:00:00ZSpectral data for simply periodic solutions of the sinh-Gordon equationKlein, Sebastianhttp://hdl.handle.net/10468/48212017-10-02T18:00:16Z2017-04-04T00:00:00ZSpectral data for simply periodic solutions of the sinh-Gordon equation
Klein, Sebastian
This note summarizes results that were obtained by the author in his habilitation thesis concerning the development of a spectral theory for simply periodic, 2-dimensional, complex-valued solutions u of the sinh-Gordon equation. Spectral data for such solutions are defined for periodic Cauchy data on a line (following Hitchin and Bobenko) and the space of spectral data is described by an asymptotic characterization. Using methods of asymptotic estimates, the inverse problem for the spectral data of such Cauchy data is answered. Finally a Jacobi variety for the spectral curve is constructed, and this is used to study the asymptotic behavior of the spectral data corresponding to actual simply periodic solutions of the sinh-Gordon equation on strips of positive height.
2017-04-04T00:00:00Z