Physical Sciences and Mathematics Commons^™

Toy Blocks And Rotational Physics, Gabriele U. Varieschi, Isabel R. Jully

Gabriele Varieschi

Have you ever observed a child playing with toy blocks? A favorite game is to build towers and then make them topple like falling trees. To the eye of a trained physicist this should immediately look like an example of the physics of “falling chimneys,” when tall structures bend and break in mid-air while falling to the ground. The game played with toy blocks can actually reproduce well what is usually seen in photographs of falling towers, such as the one that appeared on the cover of the September 1976 issue of The Physics Teacher.1 In this paper we describe …

Toy Models For The Falling Chimney, Gabriele U. Varieschi, Kaoru Kamiya

Gabriele Varieschi

In this paper we review the theory of the ‘‘falling chimney,’’ which deals with the breaking in mid-air of tall structures when they fall to the ground. We show that these ruptures can be caused by either shear forces typically developing near the base, or by the bending of the structure which is caused primarily by the internal bending moment. In the latter case the breaking is more likely to occur between one-third and one-half of the height of the chimney. Small scale toy models are used to reproduce the dynamics of the falling chimney. By examining photos taken during …

Existence Of The Mandelbrot Set In The Parameter Planes Of Certain Rational Functions, Alexander Jay Mitchell

Theses and Dissertations

In complex dynamics we compose a complex valued function with itself repeatedly and

observe the orbits of values of that function. Particular interest is in the orbit of critical

points of that function (critical orbits). One famous, studied example is the quadratic

polynomial Pc(z) = z^2 +c and how changing the value of c makes a difference to the orbit of the critical point z = 0. The set of c values for which the critical orbit is bounded is called

the Mandelbrot set.

This paper studies rational functions of the form Rn;a;c(z) = z^n + a/z^n + c and …

Ecohydrology And Groundwater Dynamics In A Salt Marsh Island, Andrea L. H. Hughes

Theses and Dissertations

Tidal salt marshes are extraordinarily productive and valuable ecosystems that provide via groundwater a not insignificant portion of coastal solute and nutrient budgets. Among the many goods and services they provide are habitat for diverse wildlife, protection for coastal communities during storms, and protection for coastal surface waters by filtering anthropogenic pollutants. One threat to the health of tidal salt marshes along the East Coast have been episodes of Acute Marsh Dieback (AMD) from 1999 to 2001. Dieback was observed at North Inlet salt marsh from 2000 to 2001. Since salt marsh hydrology is dominated by the local tidal regime, …

No-Slip Billiards, Christopher Lee Cox

Arts & Sciences Electronic Theses and Dissertations

We investigate the dynamics of no-slip billiards, a model in which small rotating disks may exchange linear and angular momentum at collisions with the boundary. A general theory of rigid body collisions in is developed, which returns the known dimension two model as a special case but generalizes to higher dimensions. We give new results on periodicity and boundedness of orbits which suggest that a class of billiards (including all polygons) is not ergodic. Computer generated phase portraits demonstrate non-ergodic features, suggesting chaotic no-slip billiards cannot easily be constructed using the common techniques for generating chaos in standard billiards. However, …

Predictability And Dynamics Of Warm-Core Mesoscale Vortex Formation With The 8 May 2009 "Super Derecho" Event, Caleb Todd Grunzke

Theses and Dissertations

The predictability and dynamics of the warm-core mesovortex associated with the northern-flank of the 8 May 2009 “Super Derecho” event are examined by coupling the Advanced Research Weather Forecasting Model with the Data Assimilation Research Testbed facility. A 50-member convection-allowing EnKF ensemble was produced with 6 hourly-cycled analysis and assimilated observations. Cycled analysis started five days prior to 1200 UTC 7 May 2009, at which time the 36 h ensemble forecasts were launched.

The ensemble forecasts all attempted to produce a mesoscale convective system (MCS) but only fourteen percent produced a warm-core mesovortex-like feature similar to the intensity of the …

Random Field Disorder At An Absorbing State Transition In One And Two Dimensions, Hatem Barghathi, Thomas Vojta

Physics Faculty Research & Creative Works

We investigate the behavior of nonequilibrium phase transitions under the influence of disorder that locally breaks the symmetry between two symmetrical macroscopic absorbing states. In equilibrium systems such "random-field" disorder destroys the phase transition in low dimensions by preventing spontaneous symmetry breaking. In contrast, we show here that random-field disorder fails to destroy the nonequilibrium phase transition of the one- and two-dimensional generalized contact process. Instead, it modifies the dynamics in the symmetry-broken phase. Specifically, the dynamics in the one-dimensional case is described by a Sinai walk of the domain walls between two different absorbing states. In the two-dimensional case, …

Yoyo Lab (Prelab), David Abbott

Handouts

No abstract provided.

Yoyo Lab (In-Lab), David Abbott

Handouts

No abstract provided.

Nonlinear Model And Qualitative Analysis For Coupled Axial/Torsional Vibrations Of Drill String, Fushen Ren, Baojin Wang, Suli Chen, Zhigang Yao, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

A nonlinear dynamics model and qualitative analysis are presented to study the key effective factors for coupled axial/torsional vibrations of a drill string, which is described as a simplified, equivalent, flexible shell under axial rotation. Here, after dimensionless processing, the mathematical models are obtained accounting for the coupling of axial and torsional vibrations using the nonlinear dynamics qualitative method, in which excitation loads and boundary conditions of the drill string are simplified to a rotating, flexible shell. The analysis of dynamics responses is performed by means of the Runge-Kutta-Fehlberg method, in which the rules that govern the changing of the …

Rate Kinetics And Molecular Dynamics Of The Structural Transitions In Amyloidogenic Proteins, Timothy Michael Steckmann

FIU Electronic Theses and Dissertations

Amyloid fibril aggregation is associated with several horrific diseases such as Alzheimer’s, Creutzfeld-Jacob, diabetes, Parkinson’s and others. The process of amyloid aggregation involves forming myriad different metastable intermediate aggregates. Amyloid fibrils are composed of proteins that originate in an innocuous α-helix or random-coil structure. The α-helices convert their structure to β-strands that aggregate into β-sheets, and then into protofibrils, and ultimately into fully formed amyloid fibrils. On the basis of experimental data, I have developed a mathematical model for the kinetics of the reaction pathways and determined rate parameters for peptide secondary structural conversion and aggregation during the entire fibrillogenesis …