Internal Wave Interaction with Broad Topography in the Presence of a Near-Bottom Stratification

This thesis considers the impact of internal waves on the transport of suspended matter across the bottom boundary layer. High resolution two- and three-dimensional direct numerical simulations of fully nonlinear, laboratory-scale internal solitary waves propagating over broad topography with a near-bottom stratified layer are presented. A near-bottom stratification is used to represent a nepheloid layer, or a layer of previously suspended material found near the bottom. The three-dimensional, mapped coordinate, spectral allocation method employed in the simulations allows for accurate modelling of the near-boundary dynamics. Noise of two amplitudes are used to initialize the three-dimensional simulations, as the natural world has a broad range of naturally occurring ``noise". Both waves of depression and elevation are considered and the formation of the two distinct types of instabilities that result is discussed. The prograde jet at the back of the wave of depression rolls up at the hill crest, with subsequent vortex production. When a near-bottom stratification is present, the resulting vortex structures are smaller, less energetic and more confined to the hill when compared to an unstratified bottom. However, the instabilities still provide a means for transport across the bottom boundary layer in a significant geographical area. In the case of a wave of elevation, a novel type of gravity current forms in the near-bottom region as the wave moves over the topography. There is intense mixing of fluid in the leading edge of the current that moves along with the wave and also provides a means for transport across the bottom boundary layer. The effects of the two noise amplitudes are considered for each type of wave. Finally, a very brief extension of the results to the field-scale is presented

COVID-19 in the West Indies: Trinidad and Tobago Experience

Trinidad and Tobago (T+T) is a small twin-island state in the Caribbean, eight miles off the coast of Venezuela. It has an area of approximately 5431 square kilometres and population of 1.4 million. At the present time, there are 116 coronavirus disease (COVID-19) cases and eight deaths, with no new cases or deaths for the last 21 days (May 17, 2020). Its COVID-19 story is one of the prompts, with early control and great success. There has beenno such instance where the health services were stretched or unable to cope. Even before the first case was identified, the T+T Government restricted entry to travelers from China, Japan, Singapore, South Korea and several European countries.The first case of COVID-19 identified in T+T was on March 12, 2020. The patient had returned from Switzerland. The next day, a second positive case was a person who had returned from USA

Giant cystic pheochromocytoma with low risk of malignancy: A case report and literature teview

Giant pheochromocytomas are rare silent entities that do not present with the classical symptoms commonly seen in catecholamine-secreting tumors. In many cases they are accidentally discovered. The algorithm to diagnose a pheochromocytoma consists of biochemical evaluation and imaging of a retroperitoneal mass. The female patient in this case report presented with a palpable abdominal mass and was cured with surgical resection. She suffered no recurrence or complications on follow-up. The left retroperitoneal mass measured 27 × 18 × 12 cm and weighed 3,315 grams. Biochemical, radiological, and pathological examinations confirmed the diagnosis of a pheochromocytoma. In this paper, we report on our experience treating this patient and provide a summary of all giant pheochromocytomas greater than 10 cm reported to date in English language medical journals. Our patient’s giant cystic pheochromocytoma was the fourth heaviest and fifth largest maximal diameter identified using our literature search criteria. Additionally, this tumor had the largest maximal diameter of all histologically confirmed benign/low metastatic risk pheochromocytomas. Giant cystic pheochromocytomas are rare entities requiring clinical suspicion coupled with strategic diagnostic evaluation to confirm the diagnosis

A case of distal extrahepatic cholangiocarcinoma with two positive resection margins

Cholangiocarcinoma is an uncommon primary malignancy of the biliary tract that is challenging to diagnose and treat effectively due to its relatively silent and late clinical presentation. The present study reports a case of a 60-year-old male with distal extrahepatic cholangiocarcinoma with a 3-week history of painless obstructive jaundice symptoms and subjective weight loss. Imaging revealed an obstructing lesion in the common bile duct, just distal to the entrance of the cystic duct. Pathology revealed moderately differentiated cholangiocarcinoma with two positive proximal resection margins. The two positive resection margins presented a challenge during surgery and points to an urgent need for further studies to better illuminate diagnostic and therapeutic options for patients with similar clinicopathological presentation

A Rheological Model for Cupuassu (Theobroma grandiflorum) Pulp at Different Concentrations and Temperatures

This work was made aiming at studying the best model for the rheological properties of Cupuassu (Theobroma grandiflorum, Schum) pulps with 14 (in nature), 17, 19, 23 and 25°Brix of total soluble solids (TSS) which were me asured at 20, 30, 40, 50 and 60°C temperature using a conc entric cylinder rheometer. The results were adjusted to the following nine models: Ostwald-de-Waele (power law), Bingham, Casson, Generalized Casson, Heinz–Casson, Herschel–Bulkley, Mizrahi–Berk, Schulmann–Haroske–Reher and Windhab. The parameters of the best model were correlated with pulp temperature and TSS by polynomial regression analysis and were kept in the regression equation only those parameters that contributed more than 1% to the variation of the independent variable. The results indicate that the rheological behavior of Cupuassu pulp in different concentrations and temperatures can be modeled by the Windhab model, although other models can be used in a narrower band of shear stress

Observations of nonlinear internal waves at a persistent coastal upwelling front

We collected high-resolution observations of nonlinear internal waves (NLIWs) at a persistent upwelling front in the shallow coastal environment (~20 m) of northern Monterey Bay, CA. The coastal upwelling front forms between recently upwelled waters and warmer stratified waters that are trapped in the bay (upwelling shadow). The front propagates up and down the coast in the along-shore direction as a buoyant plume front due to modulation by strong diurnal wind forcing. The evolution of the coastal upwelling front, and the subsequent modulation of background environmental conditions, is examined using both individual events and composite day averages. We demonstrate that regional-scale upwelling and local diurnal wind forcing are key components controlling local stratification and the formation of internal wave guides that allow for high-frequency internal wave activity. Finally, we discuss the ability of theoretical models to describe particularly large-amplitude internal waves that exist in the presence of a strong background shear and test a fully nonlinear model (i.e., the Dubreil–Jacotin–Long equation)

Measurement & analysis of energy-saving optimization systems for vending machines

The purpose of this report was to examine the functionality of load managing devices in the form of vending misers and snack misers and quantify any energy savings which could be achieved if there is full implementation of these devices on the UBC campus vending machines. Three types of machines were evaluated: a conventional chilled beverage vending machine, an Energy Star rated chilled beverage vending machine and an unrefrigerated snack machine. A watt-meter was used to gather baseline data on power and energy while an IR thermometer was used to obtain temperature readings. Thereafter, the VM-170 and SM-170 misers were installed on the vending and snack machines respectively. Surveys were issued to customers and post-miser installation data was obtained followed by data evaluation and comparative analysis on the two sets of data. It was found that the load managing devices saved 41.0%, 9.7% and 43.1% of energy on a conventional chilled beverage vending machine, an Energy Star rated chilled beverage vending machine and an unrefrigerated snack machine respectively. Based on the above percentages and payback period after a cost-benefit analysis, it was determined that the best suitable machines for misers in a full scale analysis, were conventional machines which had estimated cost savings of $73.77/year, energy savings of 126,264kWh/year and a payback period of 3.3 years (without rebate). It was found, as well, that although the average temperature of chilled beverages rose by 0.6°C, 65.7% of survey respondents were unable to distinguish a change in temperature. Through behavioural assessment, there was no need for a customer educational campaign relating to how vending machines work with vending misers since devices did not power down the machines until after closing hours when there was no occupancy. Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report.”Applied Science, Faculty ofUnreviewedGraduat

Brachial Artery Injury Accompanying Closed Elbow Dislocations

Introduction: Brachial artery injuries from elbow dislocations are uncommon, but they may lead to disastrous consequences if the diagnosis is delayed. Presentation of case: We report a case of a patient who sustained a fall onto the elbow, with dislocation and brachial artery injury, despite an ipsilateral radial pulse being palpable. Discussion: Clinicians should maintain a high index of suspicion for brachial injury when patients present with a fall onto the elbow coupled with signs suggestive of fracture-dislocation, nerve injury and/or signs of limb ischemia. Frank ischamia, however, is uncommon as there is a rich collateral anastomosis in the upper limb. Conclusion: A high index of suspicion should be maintained in order to make the diagnosis early. Exploration with excision of the injured segment and reverse vein interposition grafting is the treatment of choice in these cases