1,573 research outputs found
An investigation into unsteady base bleed for drag reduction in bluff two-box SUVs
No full textThis paper discusses a preliminary investigation into the use of base bleed on a production SUV using CFD analysis. The paper shows the methods used in creating the computational model and conducting the analysis, and present the findings to date. The paper shows that the reduction in drag increases as the mass flow rate of air is increased when the flow is deflected at the outlet. By controlling the turbulent wake to the rear of the vehicle, it is shown in the paper that mass flow rates of under 2kg/s can reduce drag coefficient by 8.2% with an outlet on the side of the vehicle, and that a mass flow rate of under 1.5kg/s can reduce the drag coefficient by 10.7% for an outlet on the upper section of the rear of the vehicle. The paper also discusses the feasibility of base bleed being applied to a production vehicle
Early sexual socialisation and sexuality education: parental perspectives: “How should we tell the children?”
No full textApplication of Advanced 2-D TDLAS diagnostics for the Optimization of Combustion in Steam Methane Reformers
No full textPaper from the AFRC 2013 conference titled Application of Advanced 2-D TDLAS diagnostics for the Optimization of Combustion in Steam Methane Reformers by Andrew Sappey.We present results from two separate demonstration installations of the ZoloBOSS TDLAS sensor system on Steam Methane Reformers. The ZoloBOSS provides two-dimensional information on temperature and species concentration distributions (O2, CO, and H2O) inside the operating SMR furnace. This unique data set allows the operator to balance the temperature distribution in the furnace as well as insuring that the desired distribution of O2 and fuel is realized. The value of such a system for operating SMRs includes contributions from improved efficiency, longer tube life, increased catalyst life, reduced emissions, remote monitoring, and safety. Results at both nominally well-run plants indicate that: 1) significant combustion profile imbalances were initially present in both furnaces upon installation, 2) the data provided by the ZoloBOSS can be used to improve balance by manually tuning burners, and 3) significant ROI will be realized as a result of long-term implementation and optimization
Weak measurements in solid state and optical systems
No full textThesis (Ph. D.)--University of Rochester. Dept. of Physics and Astronomy, 2011.
"Chapter two was co-authored with my adviser, Professor Andrew Jordan,
but I was the primary author ... Chapter three was co-authored with David J. Starling, P. Ben Dixon, Professor Andrew Jordan, and Professor John Howell. David J. Starling was the
primary author of this work and produced gures 3.1, 3.3, 3.4 and conducted the
experiment. Professor Andrew Jordan created the gure 3.2. My contribution to
this work consisted of consulting the experimental side on the theory ... Chapter four was also co-authored with my adviser, Professor Andrew Jordan, but I was the primary author of the work ... Chapter five was co-authored with David J. Starling, but I again was the
primary author ... Chapter six was co-authored with Professor Karyn Le Hur at Yale University as well as my adviser Professor Andrew Jordan. Again, I was the primary author"--Foreword.The work contained in this thesis is derived from five projects completed during my studies at the University of Rochester. The first chapter introduces general concepts useful in understanding the subsequent work. General measurement theory is discussed along with the idea of weak measurements and weak values. The second chapter discusses weak values in solid state systems and the relationship between these values and the Leggett-Garg Inequality. The calculations proceed with a quantum Bayesian approach to show the existence of the weak values, which can then be related to Leggett-Garg Inequalities through their similarities in measurement contexts. It is shown that violations of a Leggett-Garg Inequality occur if and only if a strange weak value can also be observed. The next chapter discusses a method of measuring a phase shift inspired by weak values with a sagnac interferometer. It is shown that one can measure an amplification of this phase shift with a sensitivity comparable to balanced homodyne detection, but with a much lower intensity incident on the detector. The fourth chapter presents an analysis of the entanglement dynamics of two qubits undergoing continuous parity measurement. Stochastic differential equations model the evolution and produce entanglement sudden death and genesis. Next, I detail a non-local protocol to correct for a random disturbance in amplitude or phase of an entangled pair of qubits. This correction regains part of the lost entanglement with the potential to improve quantum communication channels. The final chapter examines an aspect of quantum thermodynamics relevant at low temperatures. In these cases the coupling energy between system and environment is comparable to the system energy and can no longer be ignored as in classical thermodynamics. This can lead to violations of thermodynamical laws. An effective framework and redefinition of quantities is introduced to account for these violations
Temporal and spatial variability in speakers with Parkinson's Disease and Friedreich's Ataxia
No full textSpeech variability in groups of speakers with Parkinson's disease (PD) and with Friedreich's ataxia was compared with healthy controls. Speakers repeated the same phrase 20 times at one of two rates (fast or habitual). A non-linear analysis of variability was performed which used some of the principles behind the spatio-temporal index (STI). The STI usually employs variation in lip displacement over repetitions of the same utterance and a linear analysis of such signals is conducted to represent the combined variation in spatial and temporal control. When working with patients, audio measures (here we used speech energy) are preferred over kinematics ones as they are minimally disruptive to speech. Non-linear methods allow spatial variability to be estimated separately from temporal variability. The results are tentatively interpreted as showing that PD speakers were distinguished from healthy control speakers in spatial variability and ataxic speakers were distinguished from controls in temporal variability. These findings are consistent with the speech symptoms reported for these disorders. We conclude that the non-linear analysis using the speech energy measure is worth investigating further as it is potentially revealing of the differences underlying these two pathologies
0641: Warren D. Morrison Typescript, 1996
No full textThis collection is composed of a copy of a manuscript titled, ‘A branch of the Andrew Morrison family of Greenbrier County, (W) Virginia.’ It covers the families of Johnathan Howell Morrison (1825-1914), John Morrison (1802-1857), Andrew Morrison (1750s?-1840s?), and Nathaniel Morrison(1730?-1810?), and includes transcriptions or copies of wills and other documents related to the Morrisons
Education in post-Reformation Scotland : Andrew Melville and the University of St Andrews, 1560-1606
No full textAndrew Melville (1545-1622) was the leader of the Presbyterian wing of the Scottish
Kirk between 1574 and 1607, and he and his colleagues were a perpetual irritant to
James VI and I in his attempts to establish a royal and Episcopal dominance over the
Kirk. Yet much of Melville’s reputation has been based on the seventeenth-century
Presbyterian historical narratives written by the likes of James Melville (Andrew’s
nephew) and David Calderwood. These partisan accounts formed the basis of modern
historiography in Thomas M’Crie’s monumentally influential Life of Andrew Melville.
Modern historians broadly agree that Melville’s portrayal as a powerful and decisive
church leader in these narratives is greatly exaggerated, and that he was at best an
influential voice in the Kirk who was quickly marginalised by the adult James VI.
However, only James Kirk has commented at any length on Melville’s other role in
Jacobean Scotland—that of developing and reforming the Scottish universities.
Melville revitalised the near-defunct Glasgow University between 1574 and 1580, and
from 1580 to 1607 was principal of St Mary’s College, St Andrews, Scotland’s only
divinity college. He was also rector of the University of St Andrews between 1590
and 1597. This thesis provides a detailed account of Melville’s personal role in the
reform and expansion of the Scottish universities. This includes an analysis of his
direct work at Glasgow, but focuses primarily on St Andrews, using the untapped
archival sources held there and at the Scottish National Library and Archives to create
a detailed picture of the development of the University after the Reformation. This
thesis also evaluates the intellectual content of Melville’s reform programme, both as
it developed during his time in Paris, Poitiers and Geneva, and as we see it in action in
St Andrews
The kepler-10 planetary system revisited by harps-n : a hot rocky world and a solid neptune-mass planet
No full textKepler-10b was the first rocky planet detected by the Kepler satellite and confirmed with radial velocity follow-up observations from Keck-HIRES. The mass of the planet was measured with a precision of around 30%, which was insufficient to constrain models of its internal structure and composition in detail. In addition to Kepler-10b, a second planet transiting the same star with a period of 45 days was statistically validated, but the radial velocities were only good enough to set an upper limit of 20 M ⊕ for the mass of Kepler-10c. To improve the precision on the mass for planet b, the HARPS-N Collaboration decided to observe Kepler-10 intensively with the HARPS-N spectrograph on the Telescopio Nazionale Galileo on La Palma. In total, 148 high-quality radial-velocity measurements were obtained over two observing seasons. These new data allow us to improve the precision of the mass determination for Kepler-10b to 15%. With a mass of 3.33 ± 0.49 M ⊕ and an updated radius of R ⊕, Kepler-10b has a density of 5.8 ± 0.8 g cm–3, very close to the value predicted by models with the same internal structure and composition as the Earth. We were also able to determine a mass for the 45-day period planet Kepler-10c, with an even better precision of 11%. With a mass of 17.2 ± 1.9 M ⊕ and radius of R ⊕, Kepler-10c has a density of 7.1 ± 1.0 g cm–3. Kepler-10c appears to be the first strong evidence of a class of more massive solid planets with longer orbital periods
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Rare Insight Into the Origins of Type Ia Supernovae Progenitors From a Double Detonation
No full textAlthough Type Ia supernovae (SNe Ia) have been extensively studied, their progenitor systems and explosion mechanisms remain subjects of debate. The conventional model suggests that a white dwarf explodes in a thermonuclear runaway as it accretes mass from its companion and approaches the Chandrasekhar mass limit. However, decades ago, an alternative theory proposed that a white dwarf could explode by accumulating enough helium onto a sub-Chandrasekhar mass, triggering a full explosion in the core—a process known as double detonation. Initially, this scenario was not widely accepted because the predicted line blanketing in the blue regime did not match observations of SNe Ia. Here, I present two exceptionally rare supernovae that exhibit characteristics consistent with double detonation theories. According to the theory, the size of the helium shell around a sub-Chandrasekhar mass white dwarf significantly influences its observational characteristics. Models with thicker shells predict an early suppression in flux due to radioactive material in the remnants of the helium shell, leading to a pronounced reddish color as these remnants obscure spectral lines in the UV and blue parts of the spectrum. In contrast, thinner shell models replicate several conventional features typically associated with Type Ia supernovae around maximum light, although their early-time observables can differ significantly. My findings, which represent less than 1% of SNe Ia, have nearly doubled the sample size of these rare events in the literature, marking substantial progress in the field. Thin helium shell detonations might be the primary triggering mechanism for the majority of SNe Ia, making it even more critical to obtain early data for these supernovae. The use of artificial intelligence (AI) and upcoming surveys will be instrumental in quickly classifying and facilitating fast follow-up observations of these events. Future research is essential to determine whether this is an exotic triggering mechanism for around 1% of SNe Ia or if these events are simply the most evident examples of a mechanism that could be common to most, if not all, SNe Ia
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