Wilberforce University is a private, coed, liberal arts historically black university located in Wilberforce, Ohio. Affiliated with the African Methodist Episcopal Church, it was the first college to be owned and operated by African Americans. It participates in the United Negro College Fund.The founding of the college was unique as a collaboration in 1856 by the Cincinnati, Ohio Conference of the Methodist Episcopal Church and the African Methodist Episcopal Church . They planned a college to provide classical education and teacher training for black youth. Leaders of both races made up the first board members.When the number of students fell due to the American Civil War and financial losses closed the college in 1863, the AME Church purchased the institution to ensure its survival. Its first president, AME Bishop Daniel A. Payne, was one of the original founders. Prominent supporters and the US government donated funds for rebuilding after a fire in 1865. When the college added an industrial department in the late 19th century, state legislators could sponsor scholarship students.The college attracted the top professors of the day, including W. E. B. Du Bois. In the 19th century, it enlarged its mission to include students from South Africa. The university supports the national Association of African American Museums to broaden the reach of its programs and assist smaller museums with professional standards. Wikipedia.
Ivanov P.B.,RAS Lebedev Physical Institute |
Papaloizou J.C.B.,Wilberforce University |
Chernov S.V.,RAS Lebedev Physical Institute
Monthly Notices of the Royal Astronomical Society | Year: 2013
We determine the response of a uniformly rotating star to tidal perturbations due to a companion. General periodic orbits and parabolic flybys are considered. We evaluate energy and angular momentum exchange rates as a sum of contributions from normal modes allowing for dissipative processes. We consider the case when the response is dominated by the contribution of an identifiable regular spectrum of low-frequency modes, such as rotationally modified gravity modes.We evaluate this response in the limit of very weak dissipation, where individual resonances can be significant and also when dissipative effects are strong enough to prevent wave reflection from the neighbourhood of either the stellar surface or stellar centre, making radiation conditions more appropriate. The former situation may apply to Sun-like stars with radiative cores and convective envelopes and the latter to more massive stars with convective cores and radiative envelopes.We provide general expressions for transfer of energy and angular momentum that can be applied to an orbit with any eccentricity. Detailed calculations require knowledge of the mode spectrum and evaluation of the mode overlap integrals that measure the strength of the tidal interaction. These are evaluated for Sun-like stars in the slow rotation regime where centrifugal distortion is neglected in the equilibrium and the traditional approximation is made for the normal modes. We use both a Wentzel-Kramers-Brillouin-Jeffreys (WKBJ) procedure and a direct numerical evaluation which are found to be in good agreement for regimes of interest. The former is used to provide expressions for the mode spectrum and overlap integrals as a function of mode frequency and stellar rotation rate. These can be used to find the tidal energy and angular momentum exchange rates and hence the orbital evolution. Finally we use our formalism to determine the evolution time scales for an object, in an orbit of small eccentricity, around a Sun-like star in which the tidal response is assumed to occur. Systems with either no rotation or synchronous rotation are considered. Only rotationally modified gravity modes are taken into account under the assumption that wave dissipation proceeds close to the stellar centre. It is noted that inertial waves excited in the convective envelope may produce a comparable amount of tidal dissipation in the latter case for sufficiently large orbital periods. © 2013 The Author Published by Oxford University Press on behalf of the Royal Astronomical Society.
TAKAGI D.,Wilberforce University |
BALMFORTH N.J.,University of British Columbia
Journal of Fluid Mechanics | Year: 2011
A model is derived for long peristaltic waves propagating steadily down a fluid-filled, axisymmetric tube. The waves are driven by imposing a radial force of prescribed form on the tube. The resulting deformation of the tube wall is modelled using linear elasticity and the internal flow using the lubrication approximation. Numerical solutions for periodic wave trains and solitary waves are presented, along with asymptotic solutions at both small and large forcing amplitudes. Large-amplitude periodic waves are characterized by narrow blisters adjoining long occluded sections of the tube, whereas a solitary wave of strong contraction produces a long inflated bow wave that propels a large quantity of fluid. A measure of pumping efficacy is given by the ratio of the net fluid displacement to the power input, and is highest for a large-amplitude solitary wave.
Richardson K.J.,Wilberforce University |
Proctor M.R.E.,Wilberforce University
Geophysical and Astrophysical Fluid Dynamics | Year: 2010
We investigate the interaction of a fluctuating α-effect with large-scale shear in a simple nonlinear one-dimensional dynamo wave model. We firstly extend the calculations of Proctor [Effects of fluctuation on αΩ dynamo models. Mon. Not. R. Astron. Soc. 2007, 41, L39-L42] to include spatial variation of the fluctuations, and find that there can be a mechanism for magnetic field generation, even when the mean α is zero, provided the spatiotemporal spectrum of the fluctuations has an appropriate form. We investigate mean-field dynamo action when the new term arising from the fluctuations is non-zero, and present results concerning the stability and frequency of the solutions and parity selection in the nonlinear regime. The relation between the asymptotic theory and explicit simulation of a traditional mean-field model with a fluctuating function for the α-effect term is discussed. © 2010 Taylor & Francis.
WARNKE L.,Wilberforce University
Combinatorics Probability and Computing | Year: 2015
Concentration inequalities are fundamental tools in probabilistic combinatorics and theoretical computer science for proving that functions of random variables are typically near their means. Of particular importance is the case where f(X) is a function of independent random variables X = (X 1, . . ., Xn ). Here the well-known bounded differences inequality (also called McDiarmid's inequality or the Hoeffding–Azuma inequality) establishes sharp concentration if the function f does not depend too much on any of the variables. One attractive feature is that it relies on a very simple Lipschitz condition (L): it suffices to show that |f(X) − f(X′)| ⩽ ck whenever X, X′ differ only in Xk . While this is easy to check, the main disadvantage is that it considers worst-case changes ck , which often makes the resulting bounds too weak to be useful. In this paper we prove a variant of the bounded differences inequality which can be used to establish concentration of functions f(X) where (i) the typical changes are small, although (ii) the worst case changes might be very large. One key aspect of this inequality is that it relies on a simple condition that (a) is easy to check and (b) coincides with heuristic considerations as to why concentration should hold. Indeed, given an event Γ that holds with very high probability, we essentially relax the Lipschitz condition (L) to situations where Γ occurs. The point is that the resulting typical changes ck are often much smaller than the worst case ones. To illustrate its application we consider the reverse H-free process, where H is 2-balanced. We prove that the final number of edges in this process is concentrated, and also determine its likely value up to constant factors. This answers a question of Bollobás and Erdős. Copyright © Cambridge University Press 2015
Nam D.H.,Wilberforce University
WMSCI 2015 - 19th World Multi-Conference on Systemics, Cybernetics and Informatics, Proceedings | Year: 2015
A prediction model of the efficient measurement for air foil self-noise data using the system reduction processing is presented. The prediction model is built by data reduction techniques based on the data set of the total noise produced when an airfoil encounters smooth non-turbulent inflow with diminishing the original parameters. Each subset of parameters is selected using the various multivariate analysis techniques. Applying the reduced data, the comparison between the prediction results of multivariate analysis techniques are presented in this paper. The model performance by different algorithms with reduced parameter metrics is measured by the neurofuzzy systems with applying the Adaptive Neuro-Fuzzy Inference System. In addition, the estimated results are examined to find the best fitting technique through the comparison of the various statistical criteria.
LETZTER S.,Wilberforce University
Combinatorics Probability and Computing | Year: 2015
Answering a question raised by Dudek and Prałat, we show that if pn → ∞, w.h.p., whenever G = G(n, p) is 2-edge-coloured there is a monochromatic path of length (2/3 + o(1))n. This result is optimal in the sense that 2/3 cannot be replaced by a larger constant. As part of the proof we obtain the following result. Given a graph G on n vertices with at least (Formula presented.) edges, whenever G is 2-edge-coloured, there is a monochromatic path of length at least (Formula presented.). This is an extension of the classical result by Gerencsér and Gyárfás which says that whenever Kn is 2-coloured there is a monochromatic path of length at least 2n/3. Copyright © Cambridge University Press 2015
Teyssandier J.,CNRS Paris Institute of Astrophysics |
Terquem C.,CNRS Paris Institute of Astrophysics |
Papaloizou J.C.B.,Wilberforce University
Monthly Notices of the Royal Astronomical Society | Year: 2013
We study the dynamics of a planet on an orbit inclined with respect to a disc. If the initial inclination of the orbit is larger than some critical value, the gravitational force exerted by the disc on the planet leads to a Kozai cycle in which the eccentricity of the orbit is pumped up to large values and oscillates with time in antiphase with the inclination. On the other hand, both the inclination and the eccentricity are damped by the frictional force that the planet is subject to when it crosses the disc. We show that, by maintaining either the inclination or the eccentricity at large values, the Kozai effect provides a way of delaying alignment with the disc and circularization of the orbit. We find the critical value to be characteristically as small as about 20°. Typically, Neptune orlower mass planets would remain on inclined and eccentric orbits over the disc lifetime, whereas orbits of Jupiter or higher mass planets would align and circularize. This could play a significant role in planet formation scenarios. © 2012 The Authors.
Molecular statics and molecular dynamics simulations of the critical stress for motion of a/3 〈 1 1 2 ̄ 0 〉 screw dislocations in α-Ti at low temperatures using a modified embedded atom method potential
Rao S.I.,UES, Inc. |
Venkateswaran A.,Wilberforce University |
Acta Materialia | Year: 2013
Molecular statics and molecular dynamics, and constant temperature, constant volume (NVT) simulations, were performed to determine the core structure and critical stress for motion of a/3〈112̄0〉 screw dislocations in α-Ti at temperatures ranging from 0 to 50 K using a modified embedded atom method (MEAM) potential. Five different core structures were obtained for the a/3〈112̄0〉 screw dislocations in α-Ti, one completely spread on the prism plane, three others partially spread on the prism plane and partially spread on the pyramidal and basal planes, and one with predominantly Shockley partial splitting on the basal plane. The core completely spread on the prism plane is found to be the lowest energy structure. The Peierls stress for the minimum energy structure completely spread on the prism plane at 0 K is found to be a high value of 6.875 × 10-3 μ, where μ is the shear modulus and is independent of the orientation of the applied stress. It is shown that this high Peierls stress at 0 K is a consequence of the angular interactions in the MEAM potential. The kink-pair formation energy at zero applied stress is found to be low and equal to 0.16 eV. NVT molecular dynamics simulations show that the minimum stress required to move the screw dislocations by kink-pair formation at temperatures ranging from 5 to 50 K is significantly lower than the 0 K Peierls stress value. A classical phenomenological kink-pair model is fitted to the molecular dynamics data and used to correct for the significantly lower strain rate of deformation present in experiments as compared to molecular dynamics simulations. The corrected simulation data are in reasonable agreement with low-temperature experimental observations of yield stress in single-crystal α-Ti oriented for a/3〈112̄0〉 prism slip. The developed kink-pair model for prism slip in α-Ti will be useful in higher length scale crystal plasticity models for the deformation behavior of α-Ti. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Kudryashova N.,Wilberforce University
WWW 2014 Companion - Proceedings of the 23rd International Conference on World Wide Web | Year: 2014
Internet search market of key words attracts much attention in conjunction with the legal proceedings against Google. It has been recognized that legal argumentation alone may not be sufficient to disentangle the complexity of the case. An approach that includs mathematical modeling is needed, to distinguish the effects of the factors intrinsic to the market and the consequences of anticompetitive practices. This paper proposes a modeling framework based on explicit treatment of users' switching between the search platforms in the environment set by the platforms' strategic decisions, and demonstrates some of its applications. © Copyright 2014 by the International World Wide Web Conferences Steering Committee.
News Article | October 29, 2016
Carl E. Moyler’s new book, On Freedom and Revolt: A Comparative Investigation, ($18.49, paperback, 9781498435208; $9.99, e-book, 9781498435215) compares the writings and thoughts of two Nobel Prize winners – Albert Camus and Martin Luther King, Jr. – concerning tyranny, injustice, war, racism, poverty, exploitation and war as these oppress the peace and welfare of people. Moyler shows how these two leaders from different cultural and racial backgrounds, possibly unknown to one another – one a humanitarian agnostic and the other a seminary trained preacher – find common ground in addressing the critical issues of their time – many of the same issues being faced by some societies today. As Moyler uncovers in his riveting investigation, Camus and King were born, reared and lived as personal witnesses to many deplorable and unfair issues in society. He reveals how neither man was willing to stand in the face of those issues and do nothing. Therefore their response, based on their calling, was a revolt for freedom. This book will prove why today, they are both among the heroes who are well remembered around the world. “I hope readers will take away the thoughts, actions, and means that could bring about what both men identified as a world community of hope and caring and being ‘my brother’s keeper,’” states the author. Carl E. Moyler was born in Newport News, Virginia – one of eight children. He currently resides in Dayton, Ohio. He was a graduate of West Virginia State University in 1954 with a major in foreign languages. He holds a Masters degree in French from Case Wester Reserve University in Cleveland, Ohio. He holds a Ph.D. Comparative Literature from the Union Institute/University in Cincinnati, Ohio. He was a high school teacher of foreign languages, and a professor and an administrator at Urbana University and Wilberforce University. He is also a small business founder and president/CEO. Xulon Press, a division of Salem Media Group, is the world’s largest Christian self-publisher, with more than 15,000 titles published to date. Retailers may order On Freedom and Revolt: A Comparative Investigation through Ingram Book Company and/or Spring Arbor Book Distributors. The book is available online through xulonpress.com/bookstore, amazon.com, and barnesandnoble.com.