A continental shelf bottom boundary layer model : the effects of waves, currents, and a movable bed

Submitted in partial fulfillment of the requirements for the degree of Doctor of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution January 1983A simple model for the bottom boundary layer on the continental shelf is presented. The governing equations are developed for a stratified, turbulent Ekman layer in a combined wave and current flow over a moveable sediment bed. An eddy diffusivity closure scheme that includes the effect of suspended sediment, temperature, and salinity induced stratification on the vertical turbulent diffusion of mass and momentum couples the resulting unsteady conservation equations for fluid momentum, fluid mass, and suspended sediment mass. The wave velocity, current velocity, and suspended sediment concentration profiles predicted by the simultaneous solution of the conservation equations require the physical bottom roughness and a sediment reference concentrati on to be specified as boundary conditions. The physical bottom roughness associated with biologically generated bedforms, wave generated ripples, and near bed sediment transport are calculated as functions of the flow and sediment conditions. Using expressions for the height of sediment transporting layer and the sediment velocity, an expression for the sediment reference concentration is developed by matching laboratory measurements of sediment transport rates in oscillatory flow. The model predicts that the bottom flow field is highly dependent on (1) the nonlinear wave and current interaction, which increases the boundary shear stress and enhances vertical turbulent diffusion, (2) the effect of the boundary shear stress on a moveable sediment bed, which determines the physical bottom roughness and the amount of sediment in suspension, and (3) the effect of stable stratification, which inhibits vertical turbulent transport and couples the flow to the suspended sediment and fluid density profiles. The validity of the theoretical approach is supported by model predictions that are in excellent agreement with high quality data collected during two continental shelf bottom boundary layer experiments for a wide range of flow and bottom conditions.Funding for the work resulting in this Thesis has been provided by the American Gas Association (Project No. PR-153-126), the National Science Foundation (Grant No. OCE~8014930), and NOAA-Sea Grant (NA-79AA-D-0010l; NA 79AA-D-00102)

Puritan Revolution and the Law of Contracts

The revolutionary political, economic, and religious changes in England from the time of Henry VIII through the execution of Charles I accompanied the creation of the modern law of contracts. Most legal historians have ignored the impact of the Protestant Reformation and the rise of Puritanism on the development of the common law. Only a few historians have considered the influence of Puritanism on the law but have come to conflicting conclusions. This paper considers the question of Puritanism\u27s impact on three aspects of the common law of contracts: the rise of the writ of assumpsit, the rationalization of the doctrine of consideration, and the independence of promissory conditions. The Authors conclude that Puritan theology was irrelevant to assumpsit and consideration but could have influenced the framework of analysis of the application of virtually absolute liability in Paradine v. Jane. 1 Second, the Puritan emphasis on discipline-personals, ocial, and ecclesiastical- represents an independent source of influence on the development of the common law of contracts. The disciplined life grew in cultural significance with the Reformation and the subsequent process of confessionalization. Of the three confessional traditions arising from the Reformation, the Reformed, which included the Puritans, implemented discipline to the greatest extent. The Puritan tools of discipline-self-examination, literacy, catechizing, and local ecclesiastical implementation-proved effective. The emerging modern state valued a disciplined citizenry and eventually co-opted the social gains produced by Puritanism. The particular forms of Puritan theology and discipline were contributing factors to the English Civil War. The Civil War both precipitated the monopolization of judicial power in the common law courts and exacerbated the need for the imposition of social order from above. These factors also underlay the decision in Paradine v. Jane.2 Thus, the Authors believe that Puritan social practice influenced the common law of contracts

Alternative Sample Loading Preparation for Thermal Ionization Mass Spectrometry

This contribution describes a new sample loading method for Thermal Ionization Mass Spectrometry (TIMS), which is used in nuclear safeguards and non-proliferation efforts worldwide and is known as the “gold standard” in isotopic ratio measurements of plutonium. TIMS analysis is used to determine grades of nuclear material and the extent of enrichment at production sites. The current sample loading method for TIMS analysis is known as “bead-loading”. While it provides the lowest detection limit of any known method for plutonium analysis, bead-loading is a difficult, time consuming, and expensive method that results in up to 20% sample loss. The major encumbrance of the method is the need to manually place a small polymer bead (~40 μm diameter) containing the plutonium sample onto a narrow and fragile ionization filament. We have developed an alternative sample loading method that eliminates the difficult and time-consuming steps by pre-coating the ionization filaments with a thin polymer film. Sample loading times have been reduced from hours to minutes. The films remain stably anchored to the filament, thus preventing sample loss. Ongoing TIMS measurements are testing our hypothesis that the method will increase overall measurement efficiency/sensitivity by isolating the sample in close proximity to the filament