Scattering of coastal-trapped waves by irregularities in coastline and topography

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1988A study is conducted of the scattering of freely-propagating subinertial frequency coastal-trapped waves (CTWS) by large variations in coastline and topography using analytical and numerical techniques. Particular attention is paid to the role of stratification because, as shown, the introduction of even modest stratification can eliminate backscattered free-waves with large wavenumbers which occur, theoretically, in a barotropic ocean. An analytical solution is presented for the scattering of barotropic waves incident upon a discontinuity in shelf width. Discussion of solutions relying on backscattered free-waves is avoided by considering only the range of parameters over which energy transmission is nearly 100%. The solution shows there is a substantial transfer of energy to modes other than that of the incident wave. The transmitted mode most readily excited is that which has the across-shelf structure most closely coinciding with that of the incident wave. For a widening shelf, energy is therefore readily transferred to higher modes. The resultant presence of multiple modes produces a strong modulation in flow intensity and phase progression downstream of the scattering region which may affect the interpretation of shelf wave observations. A non-dispersive shelf wave 'pulse' of limited a10ngshelf extent scatters into a train of similarly shaped waves of all allowable modes, each propagating at its own free-wave speed. To overcome limitations of the analytical study a numerical model which accomodates arbitrary density stratification, bathymetry, and coastline, is employed. Numerical simulations are conducted of the scattering of CTWs by a set of topographic and coastline variations which are representative of many continental shelves. The strength of the scattering observed is found to be proportional to a topographic warp factor which estimates the severity of the topographic irregularities. The scattering is amplified by density stratification. A comparison of the effects of widening and narrowing topographies shows that the gross scattering effects of 'reciprocal' topographies are qnite similar. Within the scattering region itself, the strengths of the scattered-wave-induced currents exhibit substantial variation over short spatial scales. On both widening and narrowiag shelves, there is generally a marked intensification of the flow within the scattering region, and significant differences in the directions of the currents at points separated by a few tens of kilometers indicate the occurence of rapid variations ia phase. On narrowing shelves, the influence of the scattering can extend upstream into the region of uniform topography even when no freely-propagating backscattered waves exist. A simulation is condncted of CTW scattering at a site on the East Coast of Australia where observations suggest the presence of scattered freely-propagating CTWs. The success of the model simulation in reproducing features of observations confirms that realistic shelf geometries can scatter significant levels of CTW energy, and that the scattered waves can have an appreciable signal in current-meter observations made on the continental shelf. This demonstrates that along irregular coastlines it is necessary to account for the possibility that CTW scattering processes filay be in effect if oceanographic observations are to be interpreted correctly.This research was supported by the National Science Foundation under grants OCE8417769 and OCE85-21837, and by the WHOI Education Program

G.T.O.

Photograph of G.T.O. with Ronny & \u27the Daytona\u27s\u27https://scholarsjunction.msstate.edu/cht-sheet-music/2513/thumbnail.jp

Evaluation of Salmon (<i>Salmo salar</i>) and Rainbow Trout (<i>Oncorhynchus mykiss</i>) pin bones using textural analysis and micro X-ray computational tomography

Industrially, common problems arise with the deboning pin bone process, where Atlantic Salmon (Salmo salar) and Rainbow Trout (Oncorhynchus mykiss) fillets, post rigor, are subjected to a pulling process to remove the pin bones from the fillet. This study measured the length of pin bones from two species of fish and two different industrial graded weights, and then used a texture analyser and lCT X-ray to measure the pulling force, break point and volume of the pin bones of both species of fish. Results showed that salmon pin bones required significantly higher pulling force to remove pin bones from the fish fillet when compared with Trout pin bones. Interestingly Trout pin bones were significantly longer and stronger than Salmon pin bones, but had significantly lower volume. This research has progressed the issues surrounding pin boning industrially, however, more studies are required in order to understand if these differences affect the overall deboning pin bone process

The effect of collagenase, water and calcium chloride on the removal of <i>Salmo salar</i> (salmon) and <i>Oncorhynchus mykiss</i> (trout) pin bones

The aim of this study was to determine the influence of the fillet structure on the deboning force required to remove salmon and trout pin bones. Salmon and trout fillets with differing fillet structure were used, in order to study the importance of the fillet structure on the deboning process. In the first test naturally gaping and non-gaping fillets were compared. To confirm the role that the collagen plays within the fillet structure, the fillets underwent series of treatments. Fillets were put into (i) a collagenase solution to remove the collagen in the fillet (ii) a calcium chloride solution to determine if collagen was the main influential factor. Both treated salmon and trout fillets were again compared to untreated fillets from the same batch. The results indicate that collagenase and calcium chloride have a large interaction on deboning force compared to water or no treatments

Meanings of the Library Today

This essay on the mission of libraries examines the way that the manifestation of library work changes while the roles or functions abide. It treats four areas: curation, engagement with research and learning, publishing, and "library as place."Ope

Using the World-Wide Web to Deliver Complex Electronic Documents: Implications for Libraries

Explores the benefits and limitations of the World Wide Web in the context of projects taking place at the University of Virginia Library and the university's Institute for Advanced Technology in the Humanities. A gateway between the Web and PAT, a text retrieval program based on SGML (Standard Generalized Markup Language), is described

Transmission and Commoditisation of Medicinal Plant Knowledge in the Marketplaces of Oruro, Bolivia

This thesis analyses how Andean people’s knowledge of medicinal plants and the relationship between environment and health is represented, transmitted and commoditised in the marketplaces of the department of Oruro, Bolivia. Considering the increase in urban population and their dependence on marketplaces for medicinal plant remedies, this thesis examines the role of marketplaces and the importance of specialist stallholders in the transmission of knowledge. The central research site of Oruro is a multi-cultural city located on the Andean plateau in southwest Bolivia, a population of Spanish, Quechua and Aymara speakers with a pluralistic medical system. Fieldwork was carried out over 18 months with market stallholders in Oruro combining quantitative and qualitative methods with ethnographic documentation of knowledge transmission events. This thesis found that medicinal plant marketplaces in Oruro are highly regulated social systems that incorporate Andean socio-economic mechanisms, including ritual performance for the transmission of cultural knowledge, and the regulation of resource distribution and use. The development of a ‘chemical landscape’ model demonstrated that social exchange and trade between ecosystems and altitudinal zones broadens the spectrum of medicinal compounds available, contributes to the complexity of herbal mixtures and can limit exploitation of local plant populations. The market stallholders use specialist classifications that identify chemical properties, toxicity and variations between plant species and ecological regions. Plant classifications varied with the context and location in which they were used, and humoral classification enabled the selection and combination of plants in mixtures and justified remedy efficacy for specialists and non-specialists. Andean cultural beliefs including complementary opposites enabled transmission of knowledge on the medicinal properties of plants between highland consumers and lowland producers, and defined traditional Andean mixture efficacy. These findings demonstrate that, although state intervention and identity politics are redefining perceptions of medicinal knowledge, the market exchange system centred in Oruro city creates localised specialist knowledge and continuity of cultural knowledge transmission

Sensory and affective response to chocolate differing in cocoa content:a TDS and facial electromyography approach

Existing research has offered insight into facial activities and their associations with hedonic liking during the consumption of basic food samples and suggests facial changes during consumption are linked to the hedonic evaluation of tastes and, thus related to the taster's perception rather than the tastes themselves. This study tests whether, during the consumption of commercially available dark chocolate, a complex food product, which can be high in bitterness but expectedly so, how facial activities are linked to the bitterness levels and the hedonic liking of the samples. To do this we carried out two studies with untrained consumers, the first of which captured temporally dynamic sensory perception during the consumption of dark chocolate samples of 36% and 85% cocoa content, using the Temporal Dominance of Sensations (TDS) approach. The second study captured facial EMG over the corrugator and zygomaticus muscles during the consumption of dark chocolate samples (36%, 70%, and 85% cocoa). Specifically, the aim of this research was to investigate whether corrugator activity had a greater association with bitterness perception, linked to cocoa, or hedonic evaluation. Capturing the dynamic sensory profile of chocolate samples allowed an investigation into the time points most evident of sensory variation related to the bitterness and sweetness of the taste, allowing insight into whether facial activities also deviated during this time. These data offer evidence to suggest that corrugator was associated with hedonic evaluation during consumption of the samples, with the most liked samples (being those with 70% and 36% cocoa) eliciting similar corrugator activities and less activity than the least liked 85% cocoa content sample; however, there was also evidence to suggest a significant variation in participants' corrugator activity during the period of oral processing when bitterness was most evident in the 85% cocoa sample and sweetness was most evident in the 36% cocoa sample (i.e., the time when bitterness and sweetness were most divergent) Further investigation showed a variation in facial activities elicited during consumption of the 36% cocoa sample based on whether individuals were part of the group who favoured the 85% cocoa sample or the group favouring the 36% cocoa sample. The findings, therefore, suggest facial EMG, specifically over the corrugator, appears to be related to the hedonic evaluation of a complex food product and not the taste itself. Furthermore, being aware of the time points where sensory variations are most apparent between samples can allow for targeted investigation into facial EMG and its ability to distinguish food samples. [Abstract copyright: Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.

Towards an Understanding of Valence in E-Government Services

The Australian government, to remind job seekers of appointments with employment services providers in order to cut costs and free up human resources, is using technologies such as Short Messaging Services (SMS). However, the technologies in-use are but one side of this equation – the specifics of how these technologies are used is the other side, and these specifics are highly undertheorized, particularly in regard to the views of the people to which these technologies are directed. The purpose of this paper is to provide a theoretical framing for this phenomenon as well as to introduce an emerging methodological direction that may allow for a better understanding of demographic-specific values and thereby better valence framing. The paper also theorizes reactions to information that could be applicable elsewhere, not just in e-government or with SMS, thereby contributing to discussions surrounding the ‘Big Data’ debat