1,990 research outputs found
Localised states in an extended Swift-Hohenberg equation
Recent work on the behaviour of localised states in pattern forming partial
differential equations has focused on the traditional model Swift-Hohenberg
equation which, as a result of its simplicity, has additional structure --- it
is variational in time and conservative in space. In this paper we investigate
an extended Swift-Hohenberg equation in which non-variational and
non-conservative effects play a key role. Our work concentrates on aspects of
this much more complicated problem. Firstly we carry out the normal form
analysis of the initial pattern forming instability that leads to
small-amplitude localised states. Next we examine the bifurcation structure of
the large-amplitude localised states. Finally we investigate the temporal
stability of one-peak localised states. Throughout, we compare the localised
states in the extended Swift-Hohenberg equation with the analogous solutions to
the usual Swift-Hohenberg equation
Optimum hybrid vehicle configurations for heavy duty applications
Increased concern about the fuel economy of and emissions from automobiles has led to interest in the use of hybrid electric powertrains and the introduction of several production vehicles in both heavy-duty and light-duty applications. Hybrid electric vehicles (HEVs) use a combination of electric motor(s) and another power source such as an internal combustion engine (ICE) or fuel cell. While these vehicles show great potential for use in a wide variety of driving situations, the optimization of components and control strategies is quite complex.;In this thesis, Class 2B, Class 6, and Class 8 vehicles are determined by averaging a variety of actual vehicles from each class and are simulated in Microsoft Excel over a variety of driving cycles to attempt to optimize their design and control. The drive cycles are modified to represent realistic expectations of the dynamic performance of vehicles from each class. Two types of hybrid powertrains are simulated. The series HEV is propelled solely by electric motors with energy coming from batteries and an alternator driven by an ICE. The parallel HEV is propelled by both electric motors and an ICE with charging-while-driving capabilities. The model is based on power requirements for each vehicle class and addresses concerns such as engine, battery, and driveline efficiencies. The control strategy forces the engine to run at a fixed percentage of the power required at the wheels plus or minus a battery state of charge correction factor.;Fuel economy increases of 100 to 150 percent were seen for Class 6 and 8 vehicles on transient cycles while 10 to 20 percent increases were seen on more constant speed cycles. The Yard cycle, a low average demand, highly transient cycle, was shown to be particularly suited to HEVs
Master of Science
thesisAnkle sprains in an athletic setting are considered one of the most common injuries sustained. Cryokinetics is commonly used in the treatment of these injuries. Recent literature suggests dynamic balance rehabilitation is influential for faster return to functional activity. Limited research has been published on the influence Cold-Water- Immersion (CWI) has on dynamic balance performance at the ankle. We evaluate CWI influence on a modified y-balance test and postural sway. We anticipated no significant differences between a treatment and control. Alpha was set at ≤ 0.05. A crossover design was utilized with a randomized treatment and control day along with randomized reach direction. Data collection was performed in a research laboratory setting with thirty subjects (female=15 male=15, age= 24±1.5 years, ht =172.75 cm±8.0, mass=70.8±12.8 kg). Study took place over two separate data collection days consisting of treatment and control. Treatment included subjects placing the nondominant lower leg into a container of cold water (maintained between 0 - 5 °C) for a minimum of 10 minutes and maximum of 15 minutes along with self reported numbness. Post treatment, subjects were asked to perform a modified y-balance test on a force plate. If numbness was lost during testing, the subject placed the lower leg back into the container for a minimum of 5 minutes and self-reported numbness. Normalized reach direction in the anterior (ANT), posteromedial (PM), and posterolateral (PL) were recorded with an intratester reliability of (0.67-0.96). Center of Pressure (COP) excursions of means velocity squared via forceplate was calculated with anterior/posterior (R=0.86) and medial/lateral (R=0.81) values. Normalized reach and COP measures were compared using RMANOVA. There was no significant within-subject interaction on all variables [Wilks' Λ=0.70, F (df) = 0.999, p = 0.471]. ANT reach presented closest to significance and largest effect size [F=2.51, p = 0.123, effect size = 0.33]. However, subjects self-reported an increased difficulty during testing. Measures indicate no significant difference in performance of the dynamic balance task. This may reinforce earlier dynamic balance rehabilitation of acute ankle sprains. With a faster introduction to rehabilitative exercises, athletes may minimize the long-lasting effects experienced from acute ankle sprains. Further research should evaluate the effect dynamic balance has on an injured population
Robust Singular Smoothers For Tracking Using Low-Fidelity Data
Tracking underwater autonomous platforms is often difficult because of noisy,
biased, and discretized input data. Classic filters and smoothers based on
standard assumptions of Gaussian white noise break down when presented with any
of these challenges. Robust models (such as the Huber loss) and constraints
(e.g. maximum velocity) are used to attenuate these issues. Here, we consider
robust smoothing with singular covariance, which covers bias and correlated
noise, as well as many specific model types, such as those used in navigation.
In particular, we show how to combine singular covariance models with robust
losses and state-space constraints in a unified framework that can handle very
low-fidelity data. A noisy, biased, and discretized navigation dataset from a
submerged, low-cost inertial measurement unit (IMU) package, with ultra short
baseline (USBL) data for ground truth, provides an opportunity to stress-test
the proposed framework with promising results. We show how robust modeling
elements improve our ability to analyze the data, and present batch processing
results for 10 minutes of data with three different frequencies of available
USBL position fixes (gaps of 30 seconds, 1 minute, and 2 minutes). The results
suggest that the framework can be extended to real-time tracking using robust
windowed estimation.Comment: 9 pages, 9 figures, to be included in Robotics: Science and Systems
201
Solvable Leibniz algebras with triangular nilradical
A classification exists for Lie algebras whose nilradical is the triangular
Lie algebra . We extend this result to a classification of all solvable
Leibniz algebras with nilradical . As an example we show the complete
classification of all Leibniz algebras whose nilradical is .Comment: arXiv admin note: text overlap with arXiv:1307.844
Criminal Courts of Justice, Dublin
The newly completed Criminal Courts of Justice (CCJ) at Parkgate Street in Dublin 8 is the largest courts project undertaken in the history of the Irish State. The design of the heating, ventilation and air conditioning (HVAC) systems was based on computer simulated modelling of the build ing to determine the optimum plant selection and operation based on the contract conditions and energy targets. The report will analyse the computer simulated energy targets versus the actual energy consumption and assess the benefit of engineering solutions such as twin-skin facades and heat recovery based on real data. The report will draw conclusions on the real benefit of such systems with in the built environment. In addition to the energy targets, the report will discuss the commission ing processes involved in delivering the energy targets required and the importance of designing metering strategies to enable the data to be collected and analysed
Increasing the labour epidural rate in a state hospital in South Africa: challenges and opportunities
Background: A 2012 audit on labour epidural analgesia rates in Tygerberg Hospital (TBH) revealed that only 2.2% of labouring parturients received epidural analgesia. This unacceptably low number necessitated a dedicated epidural service that was subsequently initiated in June 2014 by the Department of Anaesthesiology and Critical Care to improve the quality of care in labouring patients.Methods: A retrospective follow-up audit was conducted from June 2014 to December 2015 and included data on epidural rates, indications, complications and patient satisfaction. Comparison was made with the 2012 data to evaluate the impact of change on care provided and to recommend future changes.Results: Labour epidural rates improved to 5.16% for the audit period, with 2014 and 2015 rates of 7.44% and 3.89% respectively. Daytime epidurals doubled in 2014/2015 and complication rates decreased from 32.3% in 2012 to 16%. Primary indications for epidural analgesia included pre-eclampsia, morbid obesity, primigravidity and cardiac conditions. Although 99.8% of the complications were minor and transient, one fatality was reported during the audit period. This mortality emphasises the importance of team training in every aspect of epidural analgesia, so that the desired increase in epidural rate is associated with safe practice.Conclusions: An important increase in epidural rates as well as a decrease in minor complications was observed. The fatality indicates that the expansion of the service should be accompanied by in-depth training of the entire team, so that the process becomes routine and complications are reduced. A fatal drug error, a ‘never event’, should not occur.Keywords: analgesia, audit, complications, epidural, labou
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