7,979 research outputs found
Multi-mesh gear dynamics program evaluation and enhancements
A multiple mesh gear dynamics computer program was continually developed and modified during the last four years. The program can handle epicyclic gear systems as well as single mesh systems with internal, buttress, or helical tooth forms. The following modifications were added under the current funding: variable contact friction, planet cage and ring gear rim flexibility options, user friendly options, dynamic side bands, a speed survey option and the combining of the single and multiple mesh options into one general program. The modified program was evaluated by comparing calculated values to published test data and to test data taken on a Hamilton Standard turboprop reduction gear-box. In general, the correlation between the test data and the analytical data is good
Polaron effective mass from Monte Carlo simulations
A new Monte Carlo algorithm for calculating polaron effective mass is
proposed. It is based on the path-integral representation of a partial
partition function with fixed total quasi-momentum. Phonon degrees of freedom
are integrated out analytically resulting in a single-electron system with
retarded self-interaction and open boundary conditions in imaginary time. The
effective mass is inversely proportional to the covariance of total energy
calculated on an electron trajectory and the square distance between ends of
the trajectory. The method has no limitations on values of model parameters and
on the size and dimensionality of the system although large statistics is
required for stable numerical results. The method is tested on the
one-dimensional Holstein model for which simulation results are presented.Comment: 4 pages + 1 figure, RevTeX. Accepted for publication as a Rapid
Communication in Phys.Rev.
Doing evolution in economic geography
Evolutionary approaches in economic geography face questions about the relationships between their concepts, theories, methods, politics, and policy implications. Amidst the growing but unsettled consensus that evolutionary approaches should employ plural methodologies, the aims here are, first, to identify some of the difficult issues confronting those working with different frameworks. The concerns comprise specifying and connecting research objects, subjects, and levels; handling agency and context; engaging and integrating the quantitative and the qualitative; comparing cases; and, considering politics, policy, and praxis. Second, the purpose is to articulate a distinctive geographical political economy approach, methods, and illustrative examples in addressing these issues. Bringing different views of evolution in economic geography into dialogue and disagreement renders methodological pluralism a means toward improved understanding and explanation rather than an end in itself. Confronting such thorny matters needs to be embedded in our research practices and supported by greater openness; more and better substantiation of our conceptual, theoretical, and empirical claims; enhanced critical reflection; and deeper engagement with politics, policy, and praxis
On the Localization of One-Photon States
Single photon states with arbitrarily fast asymptotic power-law fall-off of
energy density and photodetection rate are explicitly constructed. This goes
beyond the recently discovered tenth power-law of the Hellwarth-Nouchi photon
which itself superseded the long-standing seventh power-law of the Amrein
photon.Comment: 7 pages, tex, no figure
Feasibility of Implementing Community Partnerships to Provide Diabetes Prevention Services to Youth
Type 2 diabetes (T2D) in youth has increased as a result of the obesity epidemic. Diabetes prevention programming is needed for youth, at risk for T2D, and their families. However, there is a lack of diabetes prevention services for this population. There is evidence for the benefit of lifestyle modification for decreasing diabetes risk, however there are barriers for youth to access these services in a traditional clinical setting. Our Youth Diabetes Prevention Clinic (YDPC) created partnerships within the community to increase access to diabetes prevention services for at risk youth. YDPC personnel approached community organizations who had the expertise and capacity to partner in needed areas. These partnerships allowed for the development and facilitation of a community-based diabetes prevention group. Youth and their families participated in a 12 week diabetes prevention group. We measured attendance and participant satisfaction with the program. Families attended an average of 5.1 sessions from January to October 2016. Participant satisfaction was collected five times. Physical activity was rated as “awesome” or “good” by 88% of the respondents. The nutrition activities were rated as “awesome” or “good” by 97% of respondents. Physicians and families express a desire for diabetes prevention services, however barriers make it difficult for families to fully participate. Creating partnerships within the community allows for increased access to diabetes prevention services for high-risk, underserved families
What not to do in facial infrared thermographic measurements: A post data enhancement
The accuracy of infrared thermographic measurements depends on several factors, including movement of target. In this study, accuracy of nose tip temperatures obtained in a mental workload assessment using a thermal imaging camera were impacted by participants’ movement and camera zooming/panning. To correct these measurement errors, we compared manual facial landmark identification techniques using data labelling software with an automated deep learning-based approach utilised for facial landmark tracking and evaluated both against the built-in tracking features of the thermal camera, Thermal Spot Tracking. Using the Manual Thermal Landmark Annotation measurements as the ground truth, our results show that the Automated Facial Feature Tracking approach, which is the AI based approach performed better than the Thermal Spot Tracking as it matched comparatively more spatial coordinates and temperature datapoints as well as showed comparatively lower mean relative error. The study highlights the potential of AI in enhancing the accuracy of thermographic measurements, particularly in applications involving facial temperature analysis
Classical Rules in Quantum Games
We consider two aspects of quantum game theory: the extent to which the
quantum solution solves the original classical game, and to what extent the new
solution can be obtained in a classical model.Comment: The previous title, "Quantum games are no fun (yet)", was too
whimsical for Physical Review. This is a comment on most, but not all, papers
on quantum game theor
Tunneling and Non-Universality in Continuum Percolation Systems
The values obtained experimentally for the conductivity critical exponent in
numerous percolation systems, in which the interparticle conduction is by
tunnelling, were found to be in the range of and about , where
is the universal conductivity exponent. These latter values are however
considerably smaller than those predicted by the available ``one
dimensional"-like theory of tunneling-percolation. In this letter we show that
this long-standing discrepancy can be resolved by considering the more
realistic "three dimensional" model and the limited proximity to the
percolation threshold in all the many available experimental studiesComment: 4 pages, 2 figure
Comparison of Methods for Determining the Composition of Pyrolysis Products from the Degradation of Ablative Composites. Status report.
Determining composition of pyrolysis products from degradation of ablative material
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