EXPERIMENTAL AND COMPUTATIONAL ACTIVITIES AT THE OREGON STATE UNIVERSITY NEES TSUNAMI RESEARCH FACILITY

A diverse series of research projects have taken place or are underway at the NEES Tsunami Research Facility at Oregon State University. Projects range from the simulation of the processes and effects of tsunamis generated by sub-aerial and submarine landslides (NEESR, Georgia Tech.), model comparisons of tsunami wave effects on bottom profiles and scouring (NEESR, Princeton University), model comparisons of wave induced motions on rigid and free bodies (Shared-Use, Cornell), numerical model simulations and testing of breaking waves and inundation over topography (NEESR, TAMU), structural testing and development of standards for tsunami engineering and design (NEESR, University of Hawaii), and wave loads on coastal bridge structures (non-NEES), to upgrading the two-dimensional wave generator of the Large Wave Flume. A NEESR payload project (Colorado State University) was undertaken that seeks to improve the understanding of the stresses from wave loading and run-up on residential structures. Advanced computational tools for coupling fluid-structure interaction including turbulence, contact and impact are being developed to assist with the design of experiments and complement parametric studies. These projects will contribute towards understanding the physical processes that occur during earthquake generated tsunamis including structural stress, debris flow and scour, inundation and overland flow, and landslide generated tsunamis. Analytical and numerical model development and comparisons with the experimental results give engineers additional predictive tools to assist in the development of robust structures as well as identification of hazard zones and formulation of hazard plans

Variable diffusivity homogeneous surface diffusion model and analysis of merits and fallacies of simplified adsorption kinetics equations

Adsorption and ion exchange phenomena are encountered in several separation processes, which in turn, are of vital importance across various industries. Although the literature on adsorption kinetics modeling is rich, the majority of the models employed are empirical, based on chemical reaction kinetics or oversimplified versions of diffusion models. In this paper, the fifteen most popular simplified adsorption kinetics equations are presented and discussed. A new versatile variable-diffusivity two-phase homogeneous diffusion model is presented and used to evaluate the analytical adsorption models. Aspects of ion exchange kinetics are also addressed

Using Subsystem MT2 for Complete Mass Determinations in Decay Chains with Missing Energy at Hadron Colliders

We propose to use the MT2 concept to measure the masses of all particles in SUSY-like events with two unobservable, identical particles. To this end we generalize the usual notion of MT2 and define a new MT2(n,p,c) variable, which can be applied to various subsystem topologies, as well as the full event topology. We derive analytic formulas for its endpoint MT2{max}(n,p,c) as a function of the unknown test mass Mc of the final particle in the subchain and the transverse momentum pT due to radiation from the initial state. We show that the endpoint functions MT2{max}(n,p,c)(Mc,pT) may exhibit three different types of kinks and discuss the origin of each type. We prove that the subsystem MT2(n,p,c) variables by themselves already yield a sufficient number of measurements for a complete determination of the mass spectrum (including the overall mass scale). As an illustration, we consider the simple case of a decay chain with up to three heavy particles, X2 -> X1 -> X0, which is rather problematic for all other mass measurement methods. We propose three different MT2-based methods, each of which allows a complete determination of the masses of particles X0, X1 and X2. The first method only uses MT2(n,p,c) endpoint measurements at a single fixed value of the test mass Mc. In the second method the unknown mass spectrum is fitted to one or more endpoint functions MT2{max}(n,p,c)(Mc,pT) exhibiting a kink. The third method is hybrid, combining MT2 endpoints with measurements of kinematic edges in invariant mass distributions. As a practical application of our methods, we show that the dilepton W+W- and tt-bar samples at the Tevatron can be used for an independent determination of the masses of the top quark, the W boson and the neutrino, without any prior assumptions.Comment: 47 pages, 9 figures. revised version, published in JHEP. Major addition: a new appendix with the complete set of formulas for the MT2 endpoints as functions of the upstream transverse momentum pT and test mass M

Micro-abrasion–corrosion of a Co–Cr/UHMWPE couple in Ringer's solution : an approach to construction of mechanism and synergism maps for application to bio-implants

In studies of tribo-corrosion, the degradation of bio-materials has become of increasing research interest in recent years. This is because, in many cases, the interactions of the tribological and corrosion component in biological environments are not well understood. Moreover, the wide range of variables involved in the tribo-corrosion process, and the variety of materials used in such conditions, means that there are few systematic studies where materials and operating conditions are optimized. In the total replacement of hip joints, the Co-Cr/UHMWPE couple has been used widely. However, the application of any replacement joint for biological conditions will depend on many factors including the activity of the patient and the overall load imposed on the artificial joint. This means evaluation of the tribo-corrosion behaviour over a multi parameter space is important in order to assess the degradation possible for many patient/activity and body mass categories.In this work, the performance of a Co-Cr/UHMWPE couple was evaluated in Ringer's solution in a tribological situation where micron size particles particles were entrained in the contact - micro-abrasion-corrosion. The effects of applied load and potential were investigated in the study. Micro-abrasion-corrosion maps were constructed for the material indicating the mechanism of degradation, the extent of wastage and of synergy/antagonism involved in the tribo-corrosion interaction

Apparent unitarity violation in high mass region of MbW from a “hidden” top partner at high energy colliders

Perturbative unitarity conditions have been playing an important role in estimating the energy scale of new physics, including the Higgs mass as the most important example. In this letter, we show that there is a possibility to see the hint of a new physics (top quark partner) indirectly by observing an “apparent” unitarity violation in the distribution of invariant mass of b-jet and W-boson (Mbw) well above the mass of a top quark in a process of a heavy resonance decaying into a pair of top quarks. © 2016 The Author(s011Nsciescopu

Structures for Interacting Composite Fermions: Stripes, Bubbles, and Fractional Quantum Hall Effect

Much of the present day qualitative phenomenology of the fractional quantum Hall effect can be understood by neglecting the interactions between composite fermions altogether. For example the fractional quantum Hall effect at $\nu=n/(2pn\pm 1)$ corresponds to filled composite-fermion Landau levels,and the compressible state at $\nu=1/2p$ to the Fermi sea of composite fermions. Away from these filling factors, the residual interactions between composite fermions will determine the nature of the ground state. In this article, a model is constructed for the residual interaction between composite fermions, and various possible states are considered in a variational approach. Our study suggests formation of composite-fermion stripes, bubble crystals, as well as fractional quantum Hall states for appropriate situations.Comment: 16 pages, 7 figure

Comments on AdS2 solutions of D=11 Supergravity

We study the supersymmetric solutions of 11-dimensional supergravity with a factor of $AdS_2$ made of M2-branes. Such solutions can provide gravity duals of superconformal quantum mechanics, or through double Wick rotation, the generic bubbling geometry of M-theory which are 1/16-BPS. We show that, when the internal manifold is compact, it should take the form of a warped U(1)-fibration over an 8-dimensional Kahler space.Comment: 11 pages, no figure, JHEP3.cl

Extensions of AdS_5 x S^5 and the Plane-wave Superalgebras and Their Realization in the Tiny Graviton Matrix Theory

In this paper we consider all consistent extensions of the AdS_5 x S^5 superalgebra, psu(2,2|4), to incorporate brane charges by introducing both bosonic and fermionic (non)central extensions. We study the Inonu-Wigner contraction of the extended psu(2,2|4) under the Penrose limit to obtain the most general consistent extension of the plane-wave superalgebra and compare these extensions with the possible BPS (flat or spherical) brane configurations in the plane-wave background. We give an explicit realization of some of these extensions in terms of the Tiny Graviton Matrix Theory (TGMT)[hep-th/0406214] which is the 0+1 dimensional gauge theory conjectured to describe the DLCQ of strings on the AdS_5 x S^5 and/or the plane-wave background.Comment: 27 pages, LaTe

Fluctuation-Induced Interactions between Rods on a Membrane

We consider the interaction between two rods embedded in a fluctuating surface. The modification of fluctuations by the rods leads to an attractive long-range interaction between them. We consider fluctuations governed by either surface tension (films) or bending rigidity (membranes). In both cases the interaction falls off with the separation of the rods as $1/R^4$. The orientational part of the interaction is proportional to $\cos^2\left[ \theta_1+\theta_2 \right]$ in the former case, and to $\cos^2\left[ 2\left(\theta_1+\theta_2\right) \right]$ in the latter, where $\theta_1$ and $\theta_2$ are angles between the rods and the line joining them. These interactions are somewhat reminiscent of dipolar forces and will tend to align collections of such rods into chains.Comment: REVTEX, 14 pages, with 2 Postscript figure