A note on tsunamis: their generation and propagation in an ocean of uniform depth

The waves generated in a two-dimensional fluid domain of infinite lateral extent and uniform depth by a deformation of the bounding solid boundary are investigated both theoretically and experimentally. An integral solution is developed for an arbitrary bed displacement (in space and time) on the basis of a linear approximation of the complete (nonlinear) description of wave motion. Experimental and theoretical results are presented for two specific deformations of the bed; the spatial variation of each bed displacement consists of a block section of the bed moving vertically either up or down while the time-displacement history of the block section is varied. The presentation of results is divided into two sections based on two regions of the fluid domain: a generation region in which the bed deformation occurs and a downstream region where the bed position remains stationary for all time. The applicability of the linear approximation in the generation region is investigated both theoretically and experimentally; results are presented which enable certain gross features of the primary wave leaving this region to be determined when the magnitudes of parameters which characterize the bed displacement are known. The results indicate that the primary restriction on the applicability of the linear theory during the bed deformation is that the total amplitude of the bed displacement must remain small compared with the uniform water depth; even this restriction can be relaxed for one type of bed motion. Wave behaviour in the downstream region of the fluid domain is discussed with emphasis on the gradual growth of nonlinear effects relative to frequency dispersion during propagation and the subsequent breakdown of the linear theory. A method is presented for finding the wave behaviour in the far field of the downstream region, where the effects of nonlinearities and frequency dispersion have become about equal. This method is based on the use of a model equation in the far field (which includes both linear and nonlinear effects in an approximate manner) first used by Peregrine (1966) and more recently advocated by Benjamin, Bona & Mahony (1972) as a preferable model to the more commonly used equation of Korteweg & de Vries (1895). An input-output approach is illustrated for the numerical solution of this equation where the input is computed from the linear theory in its region of applicability. Computations are presented and compared with experiment for the case of a positive bed displacement where the net volume of the generated wave is finite and positive; the results demonstrate the evolution of a train of solitary waves (solitons) ordered by amplitude followed by a dispersive train of oscillatory waves. The case of a negative bed displacement in which the net wave volume is finite and negative (and the initial wave is negative almost everywhere) is also investigated; the results suggest that only a dispersive train of waves evolves (no solitons) for this case

The Korteweg-de Vries equation and water waves. Part 2. Comparison with experiments

The Korteweg-de Vries (KdV) equation is tested experimentally as a model for moderate amplitude waves propagating in one direction in relatively shallow water of uniform depth. For a wide range of initial data, comparisons are made between the asymptotic wave forms observed and those predicted by the theory in terms of the number of solitons that evolve, the amplitude of the leading soliton, the asymptotic shape of the wave and other qualitative features. The KdV equation is found to predict accurately the number of evolving solitons and their shapes for initial data whose asymptotic characteristics develop in the test section of the wave tank. The accuracy of the leading-soliton amplitudes computed by the KdV equation could not be conclusively tested owing to the viscous decay of the measured wave amplitudes; however, a procedure is presented for estimating the decay in amplitude of the leading wave. Computations suggest that the KdV equation predicts the amplitude of the leading soliton to within the expected error due to viscosity (12%) when the non-decayed amplitudes are less than about a quarter of the water depth. Indeed, agreement to within about 20% is observed over the entire range of experiments examined, including those with initial data for which the non-decayed amplitudes of the leading soliton exceed half the fluid depth

Sex-Related Color Patterns in Elytral Vittae of \u3ci\u3eDiabrotica Virgifera Virgifera\u3c/i\u3e (Coleoptera: Chrysomelidae)

We evaluated the color patterns of elytral vittae by sex in adults of Diabrotica virgifera virgifera leConte. Our study examined \u3e1000 beetles taken from a field population, a laboratory colony, and a reference collection containing 712 specimens from 15 of the United States and from the province of Ontario, Canada. The humeral and sutural vittae of each beetle\u27s elytra were classified as being separate, partially confluent, or totally confluent with each other. The distribution of these elytral patterns was not independent of sex. Males tended to have confluent or partially confluent vittae, whereas females largely had separate vittae. Nonetheless, all three patterns of elytral vittae were found in both sexes of D. v. virgifera, and many beetles of each sex had partially confluent vittae. This data shows that sexing D. v. virgifera beetles by simple examination of elytral vittae alone is unreliable

BCVoice Newsletter Creation and Evaluation: The Effect of Subject Line and Internal Links on Open Rate and Click-Through Rate for a College Newsletter

This study focused on understanding the effect of subject line on open rate and internal link placement on click-through rate in a newsletter that supported a newspaper at Bridgewater College, a small, private liberal arts college in Virginia in order to increase student engagement with and awareness of campus news. No significant difference was found in open rates between a generic and specific subject line. Similarly, no significant difference was found in click-through rate among six different types of internal link placements. Due to the high open and overall click-through rate, it is recommended that the newsletter continues

The Clean Air Act: Taking a Stick to the States

In order to evaluate the effectiveness of the Clean Air Act of 1970, this Note will first examine how one heavily industrialized state has responded to having a stick taken to it. Additionally, the federal-state relations which have resulted from the shift in emphasis from state to federal control, and industry\u27s onslaught on the courts for judicial review of actions taken by both federal and state agencies will be examined. In particular, the central role which the sulfur dioxide standards have played will serve to illustrate some of the areas in which the Clean Air Act has encountered difficulties. Sulfur dioxide is the primary pollutant emitted by the burning of coal, and the nation\u27s increased dependence on coal has created a serious test of Congress\u27 technology-forcing policy embodied in the 1970 Amendments. This is so because the control of this particular pollutant has demanded technological innovation and costly improvements to new and existing plants. As a result, industry and particularly the electric utilities, have made a concerted effort to delay implementation and undermine the deadlines established by Congress. The latter portion of this Note will consider their success rate in view of the proposed amendments to the Clean Air Act to be voted upon by the 95th Congress

Linear theory of wave generation by a moving bottom

The computation of long wave propagation through the ocean obviously depends on the initial condition. When the waves are generated by a moving bottom, a traditional approach consists in translating the ``frozen'' sea bed deformation to the free surface and propagating it. The present study shows the differences between the classical approach (passive generation) and the active generation where the bottom motion is included. The analytical solutions presented here exhibit some of the drawbacks of passive generation. The linearized solutions seem to be sufficient to consider the generation of water waves by a moving bottom.Comment: 9 pages, 2 figure

Turning Miranda Right Side Up: Post-Waiver Invocations and the Need to Update the Miranda Warnings

The article discusses the Miranda rights that is used as warnings to crime suspects who arrested by police. It informs that the full intention of the Miranda rights are not provided to suspect and are unfair, especially to suspects who have waived their rights, because they provide no guidance regarding how to invoke one\u27s right. It informs that an amendment is to be made for the warnings so that it can be effective

Rheological Investigations of Latex-Surfactant-Associative Thickener Aqueous Systems

Surfactants and Thickeners are both additives used in fully-formulated waterborne coatings to provide colloidal stability, thickening, and other functionality. The behavior of each ingredient in a coating must be understood and controlled to maintain colloidal stability as well as balance other desired properties of the liquid coating and the dry paint film. In this work, quaternary systems of Water-Latex-Thickener-Surfactant were investigated to further the understanding of their behavior in coatings. The thickener used was a well characterized, hydrophobically-modified, ethoxylated urethane (HEUR) with two C18 terminal hydrophobes and 795 average repeat units of ethylene oxide as the hydrophilic spacer. Two latexes, a hydrophobic butyl acrylate/styrene and a hydrophilic butyl acrylate/methyl methacrylate, each containing a small amount of methacrylic acid monomer were used. Six different surfactants, three non-ionic and three-anionic, were used. By maintaining the concentrations of latex and HEUR thickener as constants and varying the surfactant concentration, effects of the surfactant loading on rheology were determined. As concentration of surfactant increases, a characteristic shear-thickening maximum associated with bridging of latex particles by the HEUR thickener was seen to shift to higher shear rates; surfactants at all concentrations studied, except SDS, lowered the viscosities within the low shear rate region. Dynamic viscoelastic measurements shed further light into the behavior of the mixtures. The results will be explained based on surfactant and latex surface polarities and the competitive adsorption between the v surfactant and HEUR hydrophobes, and other interactions between surfactants and thickeners

Turning Miranda Right Side Up: Post-Waiver Invocations and the Need to Update the Miranda Warnings

The article discusses the Miranda rights that is used as warnings to crime suspects who arrested by police. It informs that the full intention of the Miranda rights are not provided to suspect and are unfair, especially to suspects who have waived their rights, because they provide no guidance regarding how to invoke one\u27s right. It informs that an amendment is to be made for the warnings so that it can be effective