5,305 research outputs found
Contra-rotating marine current turbines : single point tethered floating system - stabilty and performance
The Energy Systems Research Unit within the Department of Mechanical Engineering at the University of Strathclyde has developed a novel contra-rotating tidal turbine (CoRMaT). A series of tank and sea tests have led to the development and deployment of a small stand-alone next generation tidal turbine. Novel aspects of this turbine include its single point compliant mooring system, direct drive open to sea permanent magnet generator, and two contra-rotating sets of rotor blades. The sea testing of the turbine off the west coast of Scotland in the Sound of Islay is described; the resulting stability of a single-point tethered device and power quality from the direct drive generator is reported and evaluated. It is noted that reasonably good moored turbine stability within a real tidal stream can be achieved with careful design; however even quite small instabilities have an effect on the output electrical power quality. Finally, the power take-off and delivery options for a 250kW production prototype are described and assessed
Unexpected evolutionary proximity of eukaryotic and cyanobacterial enzymes responsible for biosynthesis of retinoic acid and its oxidation
Biosynthesis of retinoic acid from retinaldehyde (retinal) is catalysed by an aldehyde dehydrogenase (ALDH) and its oxidation by cytochrome P450 enzymes (CYPs). Herein we show by phylogenetic analysis that the ALDHs and CYPs in the retinoic acid pathway in animals are much closer in evolutionary terms to cyanobacterial orthologs than would be expected from the standard models of evolution
POL-LWIR Vehicle Detection: Convolutional Neural Networks Meet Polarised Infrared Sensors
For vehicle autonomy, driver assistance and situational awareness, it is
necessary to operate at day and night, and in all weather conditions. In
particular, long wave infrared (LWIR) sensors that receive predominantly
emitted radiation have the capability to operate at night as well as during the
day. In this work, we employ a polarised LWIR (POL-LWIR) camera to acquire data
from a mobile vehicle, to compare and contrast four different convolutional
neural network (CNN) configurations to detect other vehicles in video
sequences. We evaluate two distinct and promising approaches, two-stage
detection (Faster-RCNN) and one-stage detection (SSD), in four different
configurations. We also employ two different image decompositions: the first
based on the polarisation ellipse and the second on the Stokes parameters
themselves. To evaluate our approach, the experimental trials were quantified
by mean average precision (mAP) and processing time, showing a clear trade-off
between the two factors. For example, the best mAP result of 80.94% was
achieved using Faster-RCNN, but at a frame rate of 6.4 fps. In contrast,
MobileNet SSD achieved only 64.51% mAP, but at 53.4 fps.Comment: Computer Vision and Pattern Recognition Workshop 201
Automated analysis of non destructive evaluation data
Interpretation of NDE data can be unreliable and difficult due to the complex interaction
between the instrument, object under inspection and noise and uncertainties about the system or
data. A common method of reducing the complexity and volume of data is to use thresholds.
However, many of these methods are based on making subjective assessments from the data or
assumptions about the system which can be source of error. Reducing data whilst retaining
important information is difficult and normally compromises have to be made. This thesis has
developed methods that are based on sound mathematical and scientific principles and require
the minimum use of assumptions and subjective choices.
Optimisation has been shown to reduce data acquired from a multilayer composite panel and
hence show the ply layers. The problem can be ill-posed. It is possible to obtain a solution close
to optimum and obtain confidence on the result. Important factors are: the size of the search
space, representation of the data and any assumptions and choices made. Further work is
required in the use of model based optimisation to measure layer thicknesses from a metal
laminate panel. A number of important factors that must be addressed have been identified.
Two novel approaches to removing features from Transient Eddy-Current (TEC) data have been
shown to improve the visibility of defects. The best approach to take depends on the available
knowledge of the system.
Principal Value Decomposition (PVD) has been shown to remove layer interface reflections
from ultrasonic data. However, PVD is not suited to all problems such as the TEC data
described. PVD is best suited in the later stages of data reduction.
This thesis has demonstrated new methods and a roadmap for solving multivariate problems,
these methods may be applied to a wide range of data and problems
A contra-rotating marine current turbine on a flexible mooring : development of a scaled prototype
The contra-rotating marine current turbine concept developed by the Energy Systems Research Unit at the University of Strathclyde is aimed at extracting energy in a wide range of water depths by 'flying' a neutrally-buoyant device from a flexible, tensioned mooring. After successful proof of concept turbine trials, the development programme has moved on to investigate the performance of a scaled prototype of the complete system incorporating the turbine, submersible contra-rotating generator and mooring. The turbine/generator assembly has been tested in a towing tank, and the entire system is now undergoing sea trials. An investigation into turbine wake development (an area in which it is hoped that the contra-rotating turbine will have uniquely beneficial properties) has recently begun. Small single-rotor model turbines have been deployed in a flume. Trends observed so far are in accordance with those observed by other researchers
Synthesis of neutral nickel catalysts for ethylene polymerization – the influence of ligand size on catalyst stability
A facile synthesis of nickel salicylaldimine complexes with labile dissociating ligands is described. In addition to producing highly active ethylene polymerization catalysts, important insights into the effect of ligand size on catalyst stability and information on the mechanism of polymerization are provided
Contra-rotating marine current turbines : performance in field trials and power train developments
Development of a novel contra-rotating marine current turbine has been continuing at the University of Strathclyde. Continuous monitoring of blade bending loads during trials has enabled an investigation of blade-blade and blade-structure interactions. The former are a particular concern with a contra-rotating turbine, but there is now evidence to suggest that in normal operation these are relatively small. By contrast, blade-structure effects are clearly visible. A turbine complete with single-point mooring and submersible contra-rotating generator is presently being prepared for sea trials. Details of the machine and the test programme are described
CONCENTRATION ISSUES IN THE U.S. BEEF SUBSECTOR
Industrial Organization, Livestock Production/Industries,
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