2,947 research outputs found
Shelley Stokes-Hammond interview, 15 September 2017
No full textShelley Stokes-Hammond is the oldest daughter of Louis Stokes. She is a graduate of The Ohio State University and Goucher College. She is a historic preservationist, author and public relations manager at Howard University. This 2017 interview was collected as part of a yearlong, community-wide commemoration of the 50th anniversary of Carl Stokes\u27 election as mayor of Cleveland
Shelley Stokes-Hammond interview, 15 September 2017
No full textShelley Stokes-Hammond is the oldest daughter of Louis Stokes. She is a graduate of The Ohio State University and Goucher College. She is a historic preservationist, author and public relations manager at Howard University. This 2017 interview was collected as part of a yearlong, community-wide commemoration of the 50th anniversary of Carl Stokes\u27 election as mayor of Cleveland
Large-time behavior of the weak solution to 3D Navier-Stokes equations
No full textThe weak solution to the Navier–Stokes equations in a bounded domain D ⊂ R[superscript 3] with a smooth boundary is proved to be unique provided that it satisfies an additional requirement. This solution exists for all t ≥ 0. In a bounded domain D the solution decays exponentially
fast as t → ∞if the force term decays at a suitable rat
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Simplified Navier-Stokes equations (SNSE)
No full textTen kinds of the simplified Navier-Stokes equations (SNSE) are reviewed and also used to calculate the Jeffery-Hamel flow as well as to analyze briefly the seven kinds of flows to which the exact solutions of the complete Navier-Stokes equations (CNSE) have been found. Analysis shows that the actual differences among the solutions of the different SNSE can go beyond the range of the order of magnitude of Re-1/2 and result even in different flow patterns, therefore, how to choose the viscous terms included in the SNSE is worthy of notice where Re=S∞u∞ L/μ∞ is the Reynolds numbers. For the aforesaid eight kinds of flows, the solutions to the inner-outer-layer-matched SNSE and to the thin-layer-2-order SNSE agree completely with the exact solutions to CNSE. But the solutions to all the other SNSE are not completely consistent with the exact solutions to CNSE and not a few of them are actually the solutions of the classical boundary layer theory. The innerouter-layer-matched SNSE contains the shear stress causing angular displacement of the inormal axis with respect to the streamwise axis and the normal stress causing expansion-contraction in the direction of the normal axis and the viscous terms being of the order of magnitude of the normal stress; and it can also reasonably treat the inertial terms as well as the relation between the viscous and inertial terms. Therefore, it seems promising in respects of both mechanics and mathematics
The Development of a Partially Averaged Navier-Stokes KSKL Model
No full textA new partially averaged Navier-Stokes (PANS) closure is derived based on the k-kL (KSKL) model. The aim of this new model is to incorporate the desirable features of the KSKL model, compared to the k-ω shear stress transport model, into the PANS framework. These features include reduced eddy-viscosity levels, a lower dependency on the cell height at the wall, well-defined boundary conditions, and improved iterative convergence. As well as the new model derivation, the paper demonstrates that these desirable features are indeed maintained, for a range of modeled-to-total turbulence kinetic energy ratios (fk), and even for multiphase flow.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Ship Hydromechanics and Structure
Elementary Portuguese: A First Semester Course
No full textAn OER text to support POR101 at Dutchess Community College. Designed by Professor Craig Stokes, it takes inspiration from and modifies the OER text Bate-Papo by Eduardo Viana da Silva.NASUNY DutchessN/
Stimulated terahertz emission due to electronic Raman scattering in silicon
No full textSilicon-based semiconductors are intensively investigated over the past years as promising candidates for optoelectronic devices at terahertz (THz) frequencies [1]. Optically pumped intracenter silicon lasers, realized in the past decade in the THz range, are based on direct optical transitions between shallow levels of different shallow donors [2]. Recently, terahertz Raman laser emission has been demonstrated in silicon doped by antimony [3] and phosphorus [4].
We report on realization of terahertz lasers based on intracenter electronic Raman scattering in silicon doped by arsenic (Si:As, frequency range 4.8 – 5.1 THz and 5.9 – 6.5 THz) and silicon doped by bismuth (Si:Bi, 4.6 – 5.9 THz) under optical excitation by infrared frequency-tunable free electron laser at low lattice temperatures. The Stokes shift of the observed laser emission is equal to the Raman-active donor electronic transition between the ground 1s(A1) and the excited 1s(E) donor states. Raman terahertz gain of the lasers is similar to those observed for the donor-type terahertz silicon donor lasers
Strong solutions for the Navier–Stokes–Voigt equations with non-negative density
No full textThe aim of this work is to study the Navier–Stokes–Voigt equations that govern flows with non-negative density of incompressible fluids with elastic properties. For the associated nonlinear initial-and boundary-value problem, we prove the global-in-time existence of strong solutions (velocity, density and pressure). We also establish some other regularity properties of these solutions and find the conditions that guarantee the uniqueness of velocity and density. The main novelty of this work is the hypothesis that, in some subdomain of space, there may be a vacuum at the initial moment, that is, the possibility of the initial density vanishing in some part of the space domain.All authors were supported by the Grant No. AP19676624 Ministry of Science and Higher Education of the Republic of Kazakhstan
(Kazakhstan). The first author was also partially supported by CIDMA under the Portuguese Foundation for Science and Technology MultiAnnual Financing Program for R & D Units (FCT, https://ror.org/00snfqn58).publishe
Poisson kernel and blow-up of the second derivatives near the boundary for Stokes equations with Navier boundary condition
No full textWe derive the explicit Poisson kernel of Stokes equations in the half space with nonhomogeneous Navier boundary condition (BC) for both infinite and finite slip length. By using this kernel, for any , we construct a finite energy solution of Stokes equations with Navier BC in the half space, with bounded velocity and velocity gradient, but having unbounded second derivatives in locally near the boundary. While the Caccioppoli type inequality of Stokes equations with Navier BC is true for the first derivatives of velocity, which is proved by us in [CPAA 2023], this example shows that the corresponding inequality for the second derivatives of the velocity is not true. Moreover, we give an alternative proof of the blow-up using a shear flow example, which is simple and is the solution of both Stokes and Navier--Stokes equations
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