Performance of Oil Pumping Rings: An Analytical and Experimental Study

A steady-state design computer program was developed to predict the performance of pumping rings as functions of geometry, applied loading, speed, ring modulus, and fluid viscosity. Additional analyses were developed to predict transient behavior of the ring and the effects of temperature rises occurring in the hydrodynamic film between the ring and shaft. The analysis was initially compared with previous experimental data and then used to design additional rings for further testing. Tests were performed with Rulon, carbon-graphite, and babbit rings. The design analysis was used to size all of the rings and to select the ranges of clearances, thickness, and loading. Although full quantitative agreement was lacking, relative agreement existed in that rings that were predicted to perform well theoretically, generally performed well experimentally. Some causes for discrepanices between theory and experiment are believed to be due to starvation, leakage past the secondary seal at high pressures, and uncertainties in the small clearances and local inlet temperatures to the pumping ring. A separate preliminary analysis was performed for a pumping Leningrader seal. This anlaysis can be used to predict the film thickness and flow rate thr ough the seal as a function of pressure, speed, loading, and geometry

Intergroup Dynamics in Speech Perception: Interaction Among Experience, Attitudes and Expectations

Experience, attitudes, and expectations have been identified as separate influences on speech perception and comprehension across groups. In this study, we investigate the interaction among these three variables. 58 Australia-born participants completed an online survey and a vowel categorization task. The survey examined participants’ experience with Vietnamese-accented English and their attitudes towards Asians. The vowel categorization task examined participants’ recovery of a Vietnamese-accented speaker’s intended vowels. Half of the participants were told to expect a Vietnamese accent whereas the other half were not. Results indicated that the relationship between listener expectations and group attitudes varied according to whether or not participants had experience with the Vietnamese accent. This interaction was most clearly reflected on the ‘book’ vowel. Compared to participants who did not expect a Vietnamese accent, had no experience with the Vietnamese accent, but positive attitudes towards the Vietnamese group, those who expected a Vietnamese accent showed a decrease in accuracy on ‘book’ categorization. A decrease in ‘book’ categorization accuracy was also found for those having experience with the accent but negative attitudes. In contrast, an increase in accuracy was found for those having no experience with the Vietnamese accent and negative attitudes towards the Vietnamese group, and those having experience with the accent and positive attitudes. We concluded that expectations, experience and attitudes interact in their relationship with speech perception

Heat flow and calculus on metric measure spaces with Ricci curvature bounded below - the compact case

We provide a quick overview of various calculus tools and of the main results concerning the heat flow on compact metric measure spaces, with applications to spaces with lower Ricci curvature bounds. Topics include the Hopf-Lax semigroup and the Hamilton-Jacobi equation in metric spaces, a new approach to differentiation and to the theory of Sobolev spaces over metric measure spaces, the equivalence of the L^2-gradient flow of a suitably defined "Dirichlet energy" and the Wasserstein gradient flow of the relative entropy functional, a metric version of Brenier's Theorem, and a new (stronger) definition of Ricci curvature bound from below for metric measure spaces. This new notion is stable w.r.t. measured Gromov-Hausdorff convergence and it is strictly connected with the linearity of the heat flow.Comment: To the memory of Enrico Magenes, whose exemplar life, research and teaching shaped generations of mathematician

Reduced basis catalogs for gravitational wave templates

We introduce a reduced basis approach as a new paradigm for modeling, representing and searching for gravitational waves. We construct waveform catalogs for non-spinning compact binary coalescences, and we find that for accuracies of 99% and 99.999% the method generates a factor of about $10-10^5$ fewer templates than standard placement methods. The continuum of gravitational waves can be represented by a finite and comparatively compact basis. The method is robust under variations in the noise of detectors, implying that only a single catalog needs to be generated.Comment: Minor changes in some of the phrasing to match the version as published in PR

Eccrine porocarcinoma of the head: An important differential diagnosis in the elderly patient

Background: Eccrine porocarcinoma is a rare malignant tumor of the sweat gland, characterized by a broad spectrum of clinicopathologic presentations. Surprisingly, unlike its benign counterpart eccrine poroma, eccrine porocarcinoma is seldom found in areas with a high density of eccrine sweat glands, like the palms or soles. Instead, eccrine porocarcinoma frequently occurs on the lower extremities, trunk and abdomen, but also on the head, resembling various other skin tumors, as illustrated in the patients described herein. Observations: We report 5 cases of eccrine porocarcinoma of the head. All patients were initially diagnosed as having epidermal or melanocytic skin tumors. Only after histopathologic examination were they classified as eccrine porocarcinoma, showing features of epithelial tumors with abortive ductal differentiation. Characteristic clinical, histopathologic and immunohistochemical findings of eccrine porocarcinomas are illustrated. Conclusion: Eccrine porocarcinomas are potentially fatal adnexal malignancies, in which extensive metastatic dissemination may occur. Porocarcinomas are commonly overlooked, or misinterpreted as squamous or basal cell carcinomas as well as other common malignant and even benign skin tumors. Knowledge of the clinical pattern and histologic findings, therefore, is crucial for an early therapeutic intervention, which can reduce the risk of tumor recurrence and serious complications. Copyright (c) 2008 S. Karger AG, Basel

ACANTHEPEIRA STELLATA (WALCKENAER, 1805) (ARANEAE: ARANEIDAE), ENEMIGO NATURAL DE ESPECIES DE PHYLLOPHAGA (COLEOPTERA: MELOLONTHIDAE) EN CHIAPAS, MÉXICO

The behavior of the nocturnal spider Acanthepeira stellata (Walckenaer, 1805) as predator of chafer beetles in an agricultural parcel located in the south of San Cristobal de Las Casas, Chiapas is described

Static condensation optimal port/interface reduction and error estimation for structural health monitoring

Having the application in structural health monitoring in mind, we propose reduced port spaces that exhibit an exponential convergence for static condensation procedures on structures with changing geometries for instance induced by newly detected defects. Those reduced port spaces generalize the port spaces introduced in [K. Smetana and A.T. Patera, SIAM J. Sci. Comput., 2016] to geometry changes and are optimal in the sense that they minimize the approximation error among all port spaces of the same dimension. Moreover, we show numerically that we can reuse port spaces that are constructed on a certain geometry also for the static condensation approximation on a significantly different geometry, making the optimal port spaces well suited for use in structural health monitoring