A sufficient Competence to make them Independent: Attitudes towards Authority, Improvement and Independence in the Carolina-Virginia Backcountry, 1760-1800

One theme largely neglected by backcountry scholars to this point is the process of integration which allowed the interior as a region to fuse with the larger social and cultural ways of the rest of the South during the latter part of the eighteenth century. This study will examine, through a series of vignettes, this process of integration and ordering which allowed the backcountry to lose a number of its distinct characteristics and fostered the emergence of more clearly American and Southern values by early in the nineteenth century. At a point of departure, this dissertation will rely on the ideas of independence and improvement which drove the colonization process of British North American form the seventeenth through the nineteenth century. Though the notion of independence in Colonial American has received far more examination as a political construct because of Thomas Jefferson and the rhetoric of the American Revolution, it carried important social and economic meanings as well. In societies that included dependent women, children, servants and slaves, personal independence offered European men freedom from the will of others and autonomy in both public and private affairs. Though complete independence through land and labor acquisition remained largely an ideal, the increased possibility of attaining such status in North America encouraged many to immigrate to the eastern seaboard in the seventeenth century and multitudes to push inward from the coast during the eighteenth and nineteenth centuries

How open ocean dynamics affects coastal sea level, an investigation of the influence of the continental shelf and slope

Large scale, annual to decadal period motions in the deep ocean drive large scale gradients in dynamic sea level that are important as baseline levels with the potential to amplify short term sea level fluctuations from extreme events such as storm surges. Model projections assessing flood risk therefore depend on accurately simulating both short and long term variability. The decreasing depth of the bathymetry from the deep ocean to the shallow coastal zone tends to produce an insulating effect between the deep ocean and the coast. Nevertheless, studies show coherence between signals on- and off-shore over vast distances, implying that remote driving of the coastal sea level by deep ocean forcing is important. Western boundaries of ocean basins are of particular interest as the rotation and curvature of the Earth result in the intensification of currents and sea level gradients adjacent to the coastal zone. This thesis seeks to develop an improved physical understanding of how coastal sea level along a western boundary is related to the open ocean and to what extent this relationship depends on bottom topography h, the effects of the Coriolis parameter f, and friction. To investigate these questions, a hierarchy of idealized models is developed. Analytic and numerical solutions are sought for the linearised problem, while an idealized configuration of the NEMO General Ocean Circulation Model is developed to probe more realistic scenarios in the North Atlantic. For a homogeneous ocean layer above sloping topography that is uniform alongshore, the β-effect and bottom topography result in the mean dynamic sea level tending to follow h/f contours. The inclusion of friction allows sea level to cross these contours, with steeper topography and a larger friction parameter promoting penetration to the coast. This leads to the equatorward displaced and attenuated coastal sea level (relative to the open ocean) that is seen in observations. Fluctuations in the open ocean are shown to generate a new type of leaky Slope wave that transmits energy equatorward and dissipates locally on the slope and via the radiation of short Rossby waves into the interior ocean. Coastal sea level is explicitly related to poleward and open ocean sea level in terms of coastally trapped boundary waves and it is shown how the β-effect and friction result in enhanced wave decay that promotes signal penetration from ocean to coast. Steeper topography “kills-off” the boundary waves and also promotes penetration, tending towards the vertical sidewall solution in the steep limit. The inclusion of realistic bathymetry and non-linearity, which allows for the advection of potential vorticity, is not found to significantly alter the character of the solution. In particular, hot spots of off-slope sea level variability are found to excite waves that exert control over equatorward coastal latitudes, demonstrating the poleward control of coastal sea level along western boundaries. It is concluded that shelf seas are vulnerable to on and off-shelf variability originating many degrees of latitude further poleward, and that the representation of friction and bottom topography are important for numerical simulations to faithfully capture the effect of the open ocean on the coastal sea level

Use of Viscoelastic Changes to Demonstrate the Relationship Between Drying Parameters – A Preliminary Study

Dynamic mechanical thermal analysis (DMTA) is routinely used for mechanical analysis by the polymer industry to provide information on the viscoelastic properties of a material. This report reveals how DMTA has been used to further previous studies by providing insight into the differences between post-tanned leathers (chromium and chromium-free). It demonstrates the potential to correlate the results with an industrial application such as optimization of the drying conditions during cell rotary conditioning (CRC). DMTA can indicate leather fiber response to changes in atmospheric humidity and temperature, potentially facilitating real-time adaptation of conditions during leather drying. Initial DMTA results show that post-tanning, particularly fatliquoring, changes the rate of drying and allows scientists to advise on optimal leather drying conditions based on viscoelastic changes

Sulfide unhairing: rethinking the received wisdom

Content: The removal of hair from a hide or skin by dissolving it with a mixture of lime and sulfide is a fundamentally understood feature of leather technology. Or is it? For a long time, it has been accepted within the leather literature that, in water, sulfide may be present as either hydrogen sulfide (H2S), hydrosulfide (HS-) or sulfide (S2-), depending on the pH. pH 12 H2S(aq) ⇌ HS-(aq) ⇌ S2-(aq) The generally accepted mechanism of hair burning is sulfide attack at the cystine disulfide linkages in keratin. Also, it is believed that the unhairing reaction only proceeds at an appreciable rate in the presence of the dianionic S2- species, because that fits with the technological observation that unhairing reactions only proceed at pH greater than 12. However, recent publications have provided substantive proof that the S2- species does not exist in aqueous media at any pH: researchers were unable to observe any evidence of the S2- species in a solution of Na2S dissolved in hyper-concentrated NaOH and CsOH using Raman spectroscopy. The assigned second pKa for removal of the second proton has now been estimated to be 19, making the concentration of S2-(see below) vanishingly small. HS- ⇋ S2- + H+ There is a clear contradiction between the currently accepted mechanism for sulfide unhairing with the evidenced speciation of sulfide species in aqueous environment. Here the implications for this important process are discussed and possible alternative mechanisms postulated that fit with the new knowledge. Take-Away: It is a truism that we must understand the mechanistic principles of a process in order to control it. Here, we have a big change in thinking for ‘sulfide unhairing’, so it is vital that we understand the implications for leather science and leather technology of that change

Investigating the Cell Rotary Conditioning Mechanism Using Dynamic Mechanical Thermal Analysis

Jeyapalina et al. established that dynamic mechanical thermal analysis (DMTA) can be used to gauge the progression of leather drying. This work has now been advanced in order to understand the mechanism surrounding sorption/desorption of moisture during cell conditioning, e.g., cell rotary conditioning (CRC). This paper will demonstrate how the use of DMTA could be used to monitor changes in leather stiffness. A gravimetric moisture analysis was performed on identical leather samples to gauge the progression of desorption. The change in storage modulus (E’) was coupled to the moisture content (leather moisture and atmospheric relative humidity) to obtain a better understanding of the physical properties (specifically stiffness) of leather during a drying process. The research presented illustrates how DMTA can indicate leather fiber response to changes in atmospheric humidity and facilitate real-time adaptation of drying conditions during leather dehydration. The use of a cell conditioning system allows a tanner to control the flexibility of the material through the tension applied and the drying conditions. DMTA shows that the favorable conditions inside a CRC unit result in detectable changes to the leather fiber, similar to findings by Abrahamson and Williams-Wynn. Using this technique a researcher can dry chromium-containing and chromium-free leathers in a manner that is highly customizable to produce desired physical properties. Difficulties experienced in chromium-free leathers can also be investigated in detail using this technique

Targeted modulation of tropoelastin structure and assembly

Tropoelastin, as the monomer unit of elastin, assembles into elastic fibers that impart strength and resilience to elastic tissues. Tropoelastin is also widely used to manufacture versatile materials with specific mechanical and biological properties. The assembly of tropoelastin into elastic fibers or biomaterials is crucially influenced by key submolecular regions and specific residues within these domains. In this work, we identify the functional contributions of two rarely occurring negatively charged residues, glutamate 345 in domain 19 and glutamate 414 in domain 21, in jointly maintaining the native conformation of the tropoelastin hinge, bridge and foot regions. Alanine substitution of E345 and/or E414 variably alters the positioning and interactive accessibility of these regions, as illustrated by nanostructural studies and detected by antibody and cell probes. These structural changes are associated with a lower propensity for monomer coacervation, cross-linking into morphologically and functionally atypical hydrogels, and markedly impaired and abnormal elastic fiber formation. Our work indicates the crucial significance of both E345 and E414 residues in modulating specific local structure and higher-order assembly of human tropoelastin

Leaky slope waves and sea level: unusual consequences of the beta-effect along western boundaries with bottom topography and dissipation

Coastal Trapped Waves (CTWs) carry the ocean’s response to changes in forcing along boundaries, and are important mechanisms in the context of coastal sea level and the meridional overturning circulation. Motivated by the western boundary response to high latitude and open ocean variability, we investigate how the latitude dependence of the Coriolis parameter (β-effect), bottom topography, and bottom friction, modify the evolution of western boundary CTWs and sea level using a linear, barotropic model. For annual and longer period waves, the boundary response is characterized by modified Shelf Waves and a new class of leaky Slope Waves that propagate alongshore, typically at an order slower than Shelf Waves, and radiate short Rossby waves into the interior. Energy is not only transmitted equatorward along the slope, but also eastward into the interior, leading to the dissipation of energy locally and offshore. The β-effect and friction result in Shelf and Slope Waves that decay alongshore in the direction of the equator, decreasing the extent to which high latitude variability affects lower latitudes, and increasing the penetration of open ocean variability onto the shelf - narrower continental shelves and larger friction coefficients increase this penetration. The theory is compared against observations of sea level along the North American east coast and qualitatively reproduces the southward displacement and amplitude attenuation of coastal sea level relative to the open ocean. The implications are that the β-effect, topography, and friction are important in determining where along the coast sea level variability hot spots occur

Idealised modelling of offshore-forced sea level hot spots and boundary waves along the North American East Coast

Hot spots of sea level variability along the North American East Coast have been shown to shift in latitude repeatedly over the past 95 years and connections with a number of forcing phenomena, including the North Atlantic Oscillation (NAO) and Atlantic Meridional Overturning Circulation (AMOC), have been suggested. Using a barotropic 1/12° NEMO model of the North American East Coast (to represent the upper ocean and a homogeneous shelf), we investigate the coastal sea level response to remote sea surface height (SSH) variability along the upper continental slope. Hilbert transform Complex EOF analysis is used to investigate the responses to interannual changes in the strength of the mean winds and an idealised NAO. Variability in the mean winds produces in-phase coastal sea level variability along the entire coastline and is driven by a SSH anomaly in the subpolar gyre. Variability due to the NAO forcing is in phase along the coast south of Cape Hatteras. Interannual coastal sea level variability at a given latitude is found to be driven by off-shore SSH anomalies originating many degrees of latitude (100s km) further north, and linear barotropic trapped wave theory is used to explain the mechanism. A comparison of the results from an analytical model with those from the numerical model is used to suggest that the boundary wave mechanism is also relevant for understanding the coastal response to interior sea level change over longer time periods. Nonlinear effects are found not to significantly modify the character of the linear solution

Ice Nucleation in Sulfuric Acid and Ammonium Sulfate Particles

Cirrus clouds are composed of ice particles and are expected to form in the upper troposphere when highly dilute sulfate aerosols cool and become supersaturated with respect to ice. In the laboratory we have used Fourier transform infrared spectroscopy to monitor ice nucleation from sulfate particles for relevant compositions of sulfuric acid/water and ammonium sulfate/water aerosols. Measured freezing temperatures are presented as a function of aerosol composition, and results are compared to existing aerosol data. We find that sulfuric acid solution aerosol exhibits greater supercooling than ammonium sulfate solution aerosol of similar weight percent. Ice saturation ratios based on these measurements are also reported. We find that ammonium sulfate solution aerosol exhibits a relatively constant ice saturation of S∼1.48 for ice nucleation from 232 to 222 K, while sulfuric acid solution aerosol shows an increase in ice saturation from S∼1.53 to S∼1.6 as temperature decreases from 220 K to 200 K. These high-saturation ratios imply selective nucleation of ice from sulfate aerosols

Shallow katabatic flow on a non-uniformly cooled slope

We examine katabatic flow driven by a non-uniformly cooled slope surface but unaffected by Coriolis acceleration. A general formulation is given, valid for non-uniform surface buoyancy distributions over a down-slope length scale L≫δ0, where δ0=ν/(Nsinα)1/2 is the slope-normal Prandtl depth, for a kinematic viscosity ν, buoyancy frequency N and slope angle α. We demonstrate that the similarity solution of Shapiro and Fedorovich (J Fluid Mech 571:149–175, 2007) can remain quantitatively relevant local to the end of a non-uniformly cooled region. The usefulness of the steady similarity solution is determined by a spatial eigenvalue problem on the L length scale. Broadly speaking, there are also two modes of temporal instability; stationary down-slope aligned vortices and down-slope propagating waves. By considering the limiting inviscid stability problem, we show that the origin of the vortex mode is spatial oscillation of the buoyancy profile normal to the slope. This leads to vortex growth in a region displaced from the slope surface, at a point of buoyancy inflection, just as the propagating modes owe their existence to an inflectional velocity. Non-uniform katabatic flows that detrain fluid to the ambient are shown to further destabilise the vortex mode whereas entraining flows lead to weaker vortex growth rates. Rayleigh waves dominate in general, but the vortex modes become more significant at small slope angles and we quantify their relative growth rates