An Investigation into the Physics of Blowing Polysilicon Fuses

The semi-conductor fuses in this research are fabricated on a submicron process. A voltage potential is applied across the fuse, in order to achieve a blow. This current peaks with a short pulse in the order of tens of milliamps which has a long decrease to zero current flow, resulting in a blown fuse. A fuse blows due to the pinching together of electrically insulating material which initially surrounds the conducting pathway. The pinch cuts across the conductor, and so halts the current flow. In small-geometry fuses a cavity also forms during the blowing process. The company wishes to understand the fuse blow process mathematically in order to develop a model that can accurately simulate the blowing of the fuses. This report records the thermal, electrical, solid and fluid mechanics of the blowing process that was discussed at the Study Group, with remarks on possible future research for modelling the process

A theory for the impact of a wave breaking onto a permeable barrier with jet generation

We model a water wave impact onto a porous breakwater. The breakwater surface is modelled as a thin barrier composed of solid matter pierced by channels through which water can flow freely. The water in the wave is modelled as a finite-length volume of inviscid, incompressible fluid in quasi-one-dimensional flow during its impact and flow through a typical hole in the barrier. The fluid volume moves at normal incidence to the barrier. After the initial impact the wave water starts to slow down as it passes through holes in the barrier. Each hole is the source of a free jet along whose length the fluid velocity and width vary in such a way as to conserve volume and momentum at zero pressure. We find there are two types of flow, depending on the porosity, ß , of the barrier. If ß : 0 = ß < 0.5774 then the barrier is a strong impediment to the flow, in that the fluid velocity tends to zero as time tends to infinity. But if ß : 0.5774 = ß = 1 then the barrier only temporarily holds up the flow, and the decelerating wave water passes through in a finite time. We report results for the velocity and impact pressure due to the incident wave water, and for the evolving shape of the jet, with examples from both types of impact. We account for the impulse on the barrier and the conserved kinetic energy of the flow. Consideration of small ß gives insight into the sudden changes in flow and the high pressures that occur when a wave impacts a nearly impermeable seawall

Some mathematics for splashes: sea-wave impact on coastal structures

Structures built on the sea shore, such as harbour walls and breakwaters, are prone to damage by breaking waves. Such structures often need costly repairs especially after winter storms. The consulting company H.R. Wallingford gives ad- vice to clients who design, build and repair seawalls. H.R. continually seek theories, models and simulations to predict the wave loads on coastal structures. Mathematics helps account for the surprisingly large forces exerted by sea waves hitting seawalls. A case is made for solving Laplace’s equation, with mixed boundary conditions, to treat wave impact. Based on Euler’s equations of fluid dynamics, the theory accounts for the high accelerations and pressures during the brief time of impact. We predict a sudden change in the water-velocity field in the impacting wave. Also there is an impulsive pressure field: the pressure-impulse is a useful concept and variable for an engineer to understand the loads on a structure when hit by a breaking wave. Solv- ing mathematical problems can unveil the mystery and drama of breaking waves and splashes

Self-access language learning in museums: a materials development project

This paper reports on a project carried out at The University of Nottingham to create and evaluate English for Speakers of Other Languages (ESOL) materials with the aim of exploiting the self-access language learning possibilities that museums offer. A series of thematic resources were produced and trialed with ESOL learners in the Lincolnshire area. Feedback from the learners indicated that museums could have an important role to play in providing flexible language learning opportunities for ESOL students. The authors conclude by suggesting that other public facilities such as libraries, art galleries, botanical gardens and even football stadia could be exploited for this purpose

Arterial distribution of the human aorta: An examination of the evolutionary, developmental, and physiological bases of asymmetry.

The study of anatomy contends that “form follows function”; a disciplinary theme purporting that anatomical structures (i.e., cells, tissues, and organs) have a shape that serves its proper function. With this in mind, it is unclear why human arterial distribution off the aortic arch is asymmetrical, while the corresponding venous anatomy is symmetrical. We investigated the evolutionary, developmental, and physiological bases for the asymmetry of aortic arch branches in humans. First, we investigated the cardiovascular anatomy of ancestral species to determine if, and at what level, anatomical divergence (from aortic symmetry to asymmetry) occurs. Second, we examined the formation of the aortic arch and its branches during fetal development in order to determine if the asymmetry has an ontogenetic justification. Third, we considered the clinical implications associated with abnormal cases of aortic symmetry in humans. Based on our preliminary research, we hypothesize that while aortic arch asymmetry is likely beholden to several factors, the primary reason may likely be most attributable to the presence of other anatomical structures also located in the mediastinum (e.g., esophagus). That is, the aortic arch asymmetry has no self-serving functional purpose but is important in the proper functioning of neighboring anatomical structures