2,505 research outputs found
LONG-LASTING CRANIAL NERVE III PALSY AS A PRESENTING FEATURE OF CHRONIC INFLAMMATORY DEMYELINATING POLYNEUROPATHY
We describe a patient with chronic inflammatory demyelinating polyneuropathy (CIDP) in which an adduction deficit and ptosis in
the left eye presented several years before the polyneuropathy. A 52-year-old man presented with a 14-year history of unremitting
diplopia, adduction deficit, and ptosis in the left eye. At the age of 45 a mild bilateral foot drop and impaired sensation in the
four limbs appeared, with these symptoms showing a progressive course. The diagnostic workup included EMG/ENG which
demonstrated reduced conduction velocity with bilateral and symmetrical sensory and motor involvement. Cerebrospinal fluid
studies revealed a cytoalbuminologic dissociation.Aprolonged treatment with corticosteroids allowed a significant improvement of
the limbweakness. Diplopia and ptosis remained unchanged.This unusual formof CIDP presented as a long-lasting isolated cranial
nerve palsy. A diagnostic workup for CIDP should therefore be performed in those patients in which an isolated and unremitting
cranial nerve palsy cannot be explained by common causes
A Comparison of a Brain-Computer Interface and an Eye Tracker: Is There a More Appropriate Technology for Controlling a Virtual Keyboard in an ALS Patient?
The ability of people affected by amyotrophic lateral sclerosis (ALS), muscular dystrophy or spinal cord injuries to physically interact with the environment, is usually reduced. In some cases, these patients suffer from a syndrome known as locked-in syndrome (LIS), defined by the patient’s inability to make any move-ment but blinks and eye movements. Tech communication systems available for people in LIS are very limited, being those based on eye-tracking and brain-computer interface (BCI) the most useful for these patients. A comparative study between both technologies in an ALS patient is carried out: an eye tracker and a visual P300-based BCI. The purpose of the study presented in this paper is to show that the choice of the technology could depend on user´s preference. The evaluation of performance, workload and other subjective measures will allow us to determine the usability of the systems. The obtained results suggest that, even if for this patient the BCI technology is more appropriate, the technology should be always tested and adapted for each user.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech
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Student Research Projects With Industrial Impact
Abstract
This paper describes six final year undergraduate research projects supported by a collaboration between the Whittle Laboratory at the University of Cambridge and Reaction Engines (RE), a UK aerospace company. The collaboration is now in its fourth year of projects relating to RE's synergetic air breathing rocket engine (SABRE). The approach taken in these projects combines modern teaching pedagogy with a best practice methodology for industrial-academic collaboration and a well established framework for structuring research problems. This paper explains how the three methodologies are tailored and adapted for use with final year undergraduate research projects. The approach is mapped on to an annual project cycle which begins with the industry and academic partners deciding which topics to investigate and proceeds through student selection, the project work itself and concludes with student assessment and end-of-year reporting. The projects combine analytical, computational and experimental work and have covered counter-rotating turbomachinery, S-ducts in compressors and Helium Turbine design, all of which are topics of primary importance to the design of SABRE. Following descriptions of each of the six completed projects, the impact of the work and lessons learned are considered from the point of view of the students, the industrial partner and the academic supervisors. Overall, the students found the work extremely engaging and have all been encouraged to pursue careers in engineering, either in industry or through postgraduate study. For the industry partner the collaboration provides expertise and an approach which is not available in-house as well providing a “second look” at key technical questions. For the academics involved, the opportunity to lead research on a “real” problem with an industrial partner has proved highly motivating as well as providing opportunities for personal and career development.The student projects were funded by Reaction Engine
Rotor bar pre-fault detection in the squirrel cage induction motors
The paper deals with a diagnosis technique to detect and monitor incipient faults in the rotor bars of squirrel gage induction motors. The failure mode analysis is performed monitoring the motor axial vibrations. To accomplish the task, the authors present a mathematical model that allows relating the occurrence and the severity of the faults to the presence and the magnitude of some frequency components of the axial vibration spectrum. To validate the proposed approach, the results obtained by applying the mathematical model are compared with the ones obtained by experimental tests done on both healthy and faulty motors
Parallel Genetic Algorithms for calibrating Cellular Automata models: Application to lava flows
Cellular Automata are highly nonlinear dynamical systems which are suitable for simulating natural phenomena whose behaviour may be specified in terms of local interactions. The Cellular Automata model SCIARA, developed for the simulation of lava flows, demonstrated to be able to reproduce the behaviour of Etnean events. However, in order to apply the model for the prediction of future scenarios,
a thorough calibrating phase is required. This work presents the application of Genetic Algorithms,
general-purpose search algorithms inspired to natural selection and genetics, for the parameters optimisation of the modelSCIARA. Difficulties due to the elevated computational time suggested the adoption a Master-Slave Parallel Genetic Algorithm for the calibration of the model with respect to the 2001 Mt. Etna eruption. Results demonstrated the usefulness of the approach, both in terms of computing time and quality of performed simulations
Beam heat load analysis with COLDDIAG: a cold vacuum chamber for diagnostics
The knowledge of the heat intake from the electron beam is essential to design the cryogenic layout of superconducting insertion devices. With the aim of measuring the beam heat load to a cold bore and understanding the responsible mechanisms, a cold vacuum chamber for diagnostics (COLDDIAG) has been built. The instrumentation comprises temperature sensors, pressure gauges, mass spectrometers and retarding field analyzers, which allow to study the beam heat load and the influence of the cryosorbed gas layer. COLDDIAG was installed in the storage ring of the Diamond Light Source from September 2012 to August 2013. During this time measurements were performed for a wide range of machine conditions, employing the various measuring capabilities of the device. Here we report on the analysis of the measured beam heat load, pressure and gas content, as well as the low energy charged particle flux and
spectrum as a function of the electron beam parameters
Characterization of the parameters of interior permanent magnet synchronous motors for a loss model algorithm
The paper provides the results of a detailed experimental study on the variations of the characteristics of an interior permanent magnet synchronous motor, when load, speed and/or magnetization conditions vary. In particular, the characterization is carried out by assessing, for several working conditions, the motor parameters that influence its efficiency. From the knowledge of the variability of these parameters, it is possible to develop a dynamic model of the motor, which accurately describes its behaviour and allows estimating the power losses for whatever speed and load. In order to validate the model, the values of the power losses obtained by using the model are compared with the values measured with experimental tests. The study shows that it is possible to maximize the motor efficiency just acting on the direct axis current component and, therefore, it can be considered a first step towards the definition of a loss model algorithm for a control drive system able to minimize in real-time the power losses of the motor
Materials and technological processes for High-Gradient accelerating structures: new results from mechanical tests of an innovative braze-free cavity
Pure oxygen-free high-conductivity copper is a widely used material for manufacturing accelerating cavities working at room temperature. Several studies attempted to explain limitations associated with the maximum allowed field gradients and the behaviour of vacuum RF breakdown in copper accelerating structures through generation and movement of dislocations under stresses associated with RF electric and magnetic fields. Pure copper and also copper alloys undergo mechanical and thermal treatments to be hardened and strengthened during manufacturing, although their mechanical properties significantly change after heating above 590ˆC. High temperature brazing and diffusion bonding are assembly methods widely used to manufacture ultra-high vacuum accelerating devices. However, these processes, occurring at about 800-1000ˆC, significantly affect the mechanical properties of copper and copper alloys. We present here a novel Tungsten Inert Gas welding procedure, which is fast and keeps the high-gradient surfaces of the cavity and other components well below the copper annealing temperature. This process may be successfully used to manufacture copper-based accelerating components. This technology preserves the hardness and cleanliness of copper in order to achieve the maximum accelerating gradient
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