Flow of liquids in pipes of circular and annular cross-sections

Cover title.Prepared as part of an investigation conducted by the Engineering Experiment Station, University of Illinois at Urbana-Champaign

CPT and Other Symmetries in String/M Theory

We initiate a search for non-perturbative consistency conditions in M theory. Some non-perturbative conditions are already known in Type I theories; we review these and search for others. We focus principally on possible anomalies in discrete symmetries. It is generally believed that discrete symmetries in string theories are gauge symmetries, so anomalies would provide evidence for inconsistencies. Using the orbifold cosmic string construction, we give some evidence that the symmetries we study are gauged. We then search for anomalies in discrete symmetries in a variety of models, both with and without supersymmetry. In symmetric orbifold models we extend previous searches, and show in a variety of examples that all anomalies may be canceled by a Green-Schwarz mechanism. We explore some asymmetric orbifold constructions and again find that all anomalies may be canceled this way. Then we turn to Type IIB orientifold models where it is known that even perturbative anomalies are non-universal. In the examples we study, by combining geometric discrete symmetries with continuous gauge symmetries, one may define non-anomalous discrete symmetries already in perturbation theory; in other cases, the anomalies are universal. Finally, we turn to the question of CPT conservation in string/M theory. It is well known that CPT is conserved in all string perturbation expansions; here in a number of examples for which a non-perturbative formulation is available we provide evidence that it is conserved exactly.Comment: 52 pages.1 paragraph added in introduction to clarify assumption

Three life views: that of Ecclesiastes, of Omar Khayyám, and of Robert Browning

Thesis (M.A.)--Boston University, 1929. This item was digitized by the Internet Archive

The Problem of Time and Quantum Black Holes

We discuss the derivation of the so-called semi-classical equations for both mini-superspace and dilaton gravity. We find that there is no systematic derivation of a semi-classical theory in which quantum mechanics is formulated in a space-time that is a solution of Einstein's equation, with the expectation value of the matter stress tensor on the right-hand side. The issues involved are related to the well-known problems associated with the interpretation of the Wheeler-deWitt equation in quantum gravity, including the problem of time. We explore the de Broglie-Bohm interpretation of quantum mechanics (and field theory) as a way of spontaneously breaking general covariance, and thereby giving meaning to the equations that many authors have been using to analyze black hole evaporation. We comment on the implications for the ``information loss" problem.Comment: 30 pages, COLO-HEP-33

Of CP and other Gauge Symmetries in String Theory

We argue that \CP is a gauge symmetry in string theory. As a consequence, \CP cannot be explicitly broken either perturbatively or non-pertubatively; there can be no non-perturbative \CP-violating parameters. String theory is thus an example of a theory where all $\theta$ angles arise due to spontaneous \CP violation, and are in principle calculable.Comment: 8 page

INVESTIGATING THE INTERACTIONS BETWEEN BIOPOLYMERS AND BLOOD VIA OPTICAL MICROSCOPY

Hydrophobically modified (hm) derivatives of biopolymers such as chitosan have been shown to convert liquid blood into an elastic gel. This interesting material property could make hm-chitosan (hmC) useful as a hemostatic agent in treating severe bleeding. In this work, we attempted to probe the mechanism of action of hmC by studies on mixtures of blood cells and hmC using optical microscopy. Our results show that the presence of hydrophobic tails on hmC induces significant clustering of blood cells. We show that clustering increases as the fraction of hydrophobic tails on hmC increases, length of the hydrophobic tails increases, and as concentration of hmC increases. Finally, clustering due to hmC could be reversed by the addition of the supramolecule a-cyclodextrin, which is known to capture hydrophobes in its binding pocket. The results from this work support the earlier mechanism, with a few important modifications