2,643 research outputs found
Instability thresholds for flexible rotors in hydrodynamic bearings
Two types of fixed pad hydrodynamic bearings (multilobe and pressure dam) were considered. Optimum and nonoptimum geometric configurations were tested. The optimum geometric configurations were determined by using a theoretical analysis and then the bearings were constructed for a flexible rotor test rig. It was found that optimizing bearings using this technique produces a 100% or greater increase in rotor stability. It is shown that this increase in rotor stability is carried out in the absence of certain types of instability mechanisms such as aerodynamic crosscoupling. However, the increase in rotor stability should greatly improve rotating machinery performance in the presence of such forces as well
An evaluation of Te Rau Puawai workforce 100: Stakeholder perspectives
To evaluate the Te Rau Puawai programme, the Ministry of Health commissioned the
Maori and Psychology Research Unit of the University of Waikato in July 2001. The
overall aim of the evaluation was to provide the Ministry with a clearer understanding
of the programme including: the perceived critical success factors, the barriers if any
regarding Te Rau Puawai, the impact of the programme, the extent to which the
programme may be transferable, gaps in the programme, and suggested
improvements.
There are a number of stakeholders who do not have a direct role in the provision of
Te Rau Puawai. These people are not involved in the day to day running of Te Rau
Puawai (as do, for example, the coordinator, support team or academic mentors),
nevertheless they play an important role, contributing in a variety of ways to the
programme
On the definition and practical use of crystal-based azimuthal angles
A diffractometerâindependent definition of the azimuthal angle Ï of a Bragg reflection is proposed. After completion of intensity measurement, instrumentâdependent and partly redundant quantities such as orientation matrix and setting angles may be replaced by Ï, values without loss of information. Dataâtreatment software, such as absorptionâ and anisotropic extinctionâcorrection programs, become instrument independent and completely general. Formulae are given to compute Ï for equatorial and nonâequatorial diffraction geometries
Origin Gaps and the Eternal Sunshine of the Second-Order Pendulum
The rich experiences of an intentional, goal-oriented life emerge, in an
unpredictable fashion, from the basic laws of physics. Here I argue that this
unpredictability is no mirage: there are true gaps between life and non-life,
mind and mindlessness, and even between functional societies and groups of
Hobbesian individuals. These gaps, I suggest, emerge from the mathematics of
self-reference, and the logical barriers to prediction that self-referring
systems present. Still, a mathematical truth does not imply a physical one: the
universe need not have made self-reference possible. It did, and the question
then is how. In the second half of this essay, I show how a basic move in
physics, known as renormalization, transforms the "forgetful" second-order
equations of fundamental physics into a rich, self-referential world that makes
possible the major transitions we care so much about. While the universe runs
in assembly code, the coarse-grained version runs in LISP, and it is from that
the world of aim and intention grows.Comment: FQXI Prize Essay 2017. 18 pages, including afterword on
Ostrogradsky's Theorem and an exchange with John Bova, Dresden Craig, and
Paul Livingsto
Unspecified Verticality of Franck-Condon Transitions, Absorption and Emission Spectra of Cyanine Dyes, and a Classically Inspired Approximation
The computed vertical energy, Ev,a/f, from the equilibrium geometry of the initial electronic state is frequently considered as representative of the experimental excitation/emission energy, Eabs/fl = hc/λmax. Application of the quantum mechanical version of the FranckâCondon principle does not involve precise specification of nuclear positions before, after, or during an electronic transition. Moreover, the duration of an electronic transition is not experimentally accessible in spectra with resolved vibrational structure. It is shown that computed vibronic spectra based on TDDFT methods and application of quantum mechanical FC analysis predict Eabs = hc/λmax with a 10-fold improvement in accuracy compared to Ev,a for nine cyanine dyes. It is argued that part of the reason for accuracy when this FC analysis is compared to experiment as opposed to Ev,a/f is the unspecified verticality of transitions in the context of the quantum version of the FC principle. Classical FC transitions that preserve nuclear kinetic energy before and after an electronic transition were previously found to occur at a weighted average of final and initial electronic state molecular geometries known as the r-centroid. Inspired by this approach a qualitative method using computed vertical and adiabatic energies and the harmonic approximation is developed and applied yielding a 5-fold improvement in accuracy compared to Ev,a. This improvement results from the dominance of low frequency vibronic transitions in the cyanine dye major band. The model gives insight into the nature of the redshift when qPCR dye EvaGreen is complexed to λDNA and is applicable to the low frequency band of similar non cyanine dyes such as curcumin. It is found that the computed vibronic cyanine dye spectra from time-dependent FC analysis at 0 K and 298 K show decreased intensity at higher temperature suggestive of increased intensity with restricted motion shown when cyanine dyes are used in biomedical imaging. A 2-layer ONIOM model of the DNA minor groove indicates restricted motion of the TC-1 dye excited state in this setting indicative of enhanced fluorescence
Incentive Sensitization for Exercise Reinforcement to Increase Exercise Behaviors
Individuals can be sensitized to the reinforcing effects of exercise, although it is unknown if this process increases habitual exercise behavior. Sedentary men and women (body mass index: 25â35âkg/m2, Nâ=â52) participated in a 12-week aerobic exercise intervention. Exercise reinforcement was determined by how much work was performed for exercise relative to a sedentary alternative in a progressive ratio schedule task. Habitual physical activity was assessed via accelerometry. Post-intervention increases in exercise reinforcement predicted increases in physical activity bouts among those who expended over 2000 kcalâper week in exercise and who compensated for less than 50âpercent of their exercise energy expenditure
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