From the position data of 23 drifters over the four years period, 1982 to 1985, the upper layer kinematics of the Northeast Pacific were investigated. The focus of this study was upon the topographic influence, wind forcing, and Rossby waves. The notions of homogeneity and stationarity were applied to both the Eulerian and Lagrangian analysis. A new computational scheme was proposed and tested in order to explicitly take into account the Lagrangian characteristics of the drifter data. The Eulerian analysis showed that the spatial and temporal distributions of the mean current and the mean wind stress were in good agreement. Three of the four eddy kinetic energy maxima found in the region geographically corresponded to topographic features. Also the velocity field of this region appeared to be strongly inhomogeneous, non-stationary, and anisotropic. The results from the Lagrangian analysis showed that the spectral slope for the periods shorter than 5 days followed the -2 law, and suggested that the direct wind forcing was a dominant mechanism for those periods. The spectrum of the eddy component of the velocity appeared to be white for the periods longer than 10 days. The results showed that the linear Rossby waves were not dominant mechanism for upper layer dynamics of this region. The rotary spectra illustrated some evidence of the rotational preference of the cyclonic over anti-cyclonic motions at a period of 10 days. The new scheme provided meaningful information about the eddy component of the velocity. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The purpose of this investigation was to determine the parameters of emitter drift and to suggest a mechanism for this phenomenon.

Magíster en Ciencias de la Ingeniería, Mención Eléctrica / Ingeniero Civil Eléctrico / Las simulaciones computacionales son un importante recurso para ayudar en el diseño y a entender el funcionamiento de dispositivos semiconductores de una forma rápida y económica, por lo que se han desarrollado diversas herramientas de simulación, tanto comerciales como libres. No obstante, diversos centros de investigación y universidades han optado por desarrollar programas propios, lo que les permite tener continuidad en el desarrollo, control y mayor entendimiento de los fenómenos simulados. Bajo esta misma idea, el presente trabajo tiene como objetivo desarrollar herramientas de simulación para materiales y dispositivos semiconductores, centrado principalmente en el problema en dos dimensiones, y que tenga la flexibilidad suficiente para propósitos prácticos de diseño y educacionales, sirviendo además como un punto de partida para trabajos futuros. Para cumplir el objetivo mencionado, se implementaron dos modelos clásicos de simulación: Arrastre-Difusión o DD (Drift-Diffusion) y Monte Carlo o MC (que resuelve la ecuacion de transporte de Boltzmann). Dichos modelos tienen diferentes grados de precisión, capacidades y costos computacionales, cubriendo así un gran rango de dispositivos y necesidades. Para ambos, se utilizó una malla no estructurada de Voronoi, para cuya generación se presenta un algoritmo basado en la triangulación de Delaunay, lo que permite la descripción de diversas topologías. Ambos modelos fueron incluidos en un mismo programa escrito en MATLAB, con una interfaz basada en archivos de texto de alto nivel que permite el uso casi indistinto entre uno u otro, característica que le da otorga una mayor flexibilidad y simpleza. La realización de distintas pruebas numéricas y comparaciones con la literatura y otras referencias, permitieron verificar el apropiado funcionamiento de los métodos y mostrar distintas características de éstos. En particular, para DD se constató la superioridad Newton-Raphson (NRM) sobre Gummel, y de el esquema de estabilización de Schaffeter-Gummel (SG) sobre Aguas Arriba. Para MC, se desarrollaron distintas técnicas para que el método fuese coherente con la malla no estructurada y topologías generalizadas. Además, se compararon DD y MC, mostrando sus diferencias en congruencia con la literatura. El modelo de DD implementado es resuelto usando Volumenes Finitos y el método de NRM, que otorga buenas características de convergencia. Para la estabilización, se utilizó la discretización de SG. Modelos básicos de movilidad, heterojunturas y condiciones de borde, fueron incluidos para extender la versatilidad del método y establecer ideas para futuras mejoras. El método de Monte Carlo implementado en esta instancia, incluye fuentes básicas de dispersión y utiliza bandas analíticas esféricas o elípticas con no-parabolicidad para electrones. En cambio, para huecos, sólo simples modelos parabólicos e isotrópicos fueron considerados. Finalmente, fueron señaladas las limitaciones más relevantes del programa y los posibles modelos para paliarlas. Esto, junto con el resto del trabajo, se espera que se constituyan como bases para futuros desarrollos y mejoras.

Wage increases received outside of central agreements in Sweden have been declining since the turn of the millennia and are now at an almost non existing level. These wage increases are called wage drift and this study focuses on explaining the variables that determine the wage drift. Through time and sectoral analyses this study contributes with new perspectives regarding the wage setting process in Sweden looked past in earlier research. Our findings suggest an existing robust relationship between wage drift and inflation as well as unemployment. Additionally, central agreements were shown to have a significant effect on the wage drift. Finally, the foreign direct investments also had a somewhat weaker but still impactful effect on the wage drift. Our time period of 2001-2019 includes a financial crisis that heavily affected many of our explanatory variables. Our study concludes that the unemployment as well as the foreign direct investment have had a relatively larger impact after the crisis compared to before. On the contrary the central agreements seem to have had a relatively smaller impact on the wage drift after the crisis compared to before. When considering potential differences within our sectors and their impact on wage drift we found significant differences, especially regarding the central agreements.

Für zahlreiche technische Prozesse ist die Kenntnis des Schlupfes bzw. des Drift-Fluxes in Zweiphasenströmungen notwendig. Beispiele sind die Bestimmung der Druckverluste sowie der Wärme- und Stoffübertragungsvorgänge in Verdampfern oder Kondensatoren, der Phasenverweilzeit in chemischen Reaktoren sowie der Moderatorwirkung des zweiphasigen Kühlmittels innerhalb des Kerns eines Siedewasserreaktors.

Icebergs calved from high-latitude glaciers and ice shelves pose a threat to vessels and offshore infrastructure at a time when Arctic shipping and resource exploration are increasing. Knowledge of the location of potential ice hazards is therefore critical to ensure safe and efficient operations in this remote region. The Canadian Ice Service (CIS; Environment and Climate Change Canada) provides information to stakeholders on the observed and predicted distribution of icebergs in Canadian waters by combining iceberg observations with forecasts from the North American Ice Service (NAIS) iceberg drift model. The NAIS model estimates the forces acting on an iceberg to predict its future position and velocity. It is widely used for the east coast of Canada but largely unproven in the Arctic and suffers from insufficient validation due to a paucity of reliable in-situ observations of iceberg drift. This study represents the first comprehensive validation of the NAIS iceberg drift model for the Canadian Arctic. A total of 133 hindcast simulations for the period 2009-2019 were performed against in-situ drift observations of 44 icebergs. These data, collated in an iceberg beacon database (compiled by Carleton University and CIS), includes observations collected by Cryologgers; novel iceberg tracking beacons designed as part of this study. Quantified comparisons of the distance error between observed and modelled drift tracks indicate that the NAIS model produces realistic simulations of iceberg drift in Baffin Bay. Root mean square error after 24-hours of simulated drift ranged from 18-22 km and increased at a daily rate of 11-13 km, which is typical of previous model verification and validation studies. Improved model performance was observed for longer (>250 m) and deeper-keeled (>100 m) icebergs, which appears to counteract the model’s tendency to overestimate drift by reducing the influence of stronger surface ocean currents acting on the iceberg. Ocean current direction, wind direction, and iceberg keel geometry were identified by a sensitivity analysis as the model parameters and environmental driving forces that have the greatest influence on modelled iceberg drift. These results emphasize the need for accurate environmental information and underscore the importance of properly representing the physical characteristics of icebergs in drift models.

New transgenic crops are currently being developed which will be tolerant to dicamba and 2,4-D herbicides. This technology could greatly benefit producers who are impacted by weed species that have developed resistance to other herbicides, like glyphosate-resistant Palmer Amaranth. Adoption of this new technology is likely to be rapid and widespread which will lead to an increase in the amount of dicamba and 2,4-D applied each season. It is well-documented that these herbicides are very injurious to soybeans, cotton, tomatoes, and most other broadleaf crops, and their increased use brings along increased chances of physical spray drift onto susceptible crops. Because of these risks, research is being conducted on new herbicide formulation/spray nozzle combinations to determine management options which may minimize physical spray drift.

No description available.

Dicamba drift is a common issue and has been known to cause injury and yield reduction in a wide range of susceptible crops. A study was established to evaluate the effects of a simulated drift on the plant growth and yield of two pumpkin varieties (Cucurbita pepo ‘Magic Wand’ and C. moschata ‘Autumn Buckskin’) during 2019 and 2020 at the Southern Illinois University Horticulture Research Center in Carbondale. Six rates of dicamba were applied to simulate a mid-post-emergence application made in soybean which drifted onto pumpkins at two growth stages, 8-leaf and 12-leaf. These two pumpkin growth stages would be the approximate size of pumpkins when a mid-post-emergence application would typically be made in soybean. The 12-leaf growth stage also corresponds with Simulated drift rates were targeted at 1/1026, 1/513, 1/256, 1/128, 1/64, 1/32 of a 0.56 kg ae ha-1 rate, corresponding to 0.00056, 0.00112, 0.00224, 0.00448, 0.00896, and 0.01792 kg ae ha-1. Actual dicamba deposition was measured used filter papers (surface area = 176.1 cm2) in each treatment and these measured exposure amounts were used in correlational analyses with pumpkin injury, growth, and yield responses. Pumpkin plants did not develop chlorosis or necrosis at any point of the growing season with any of the dicamba application treatments. However, some injury and stunting were observed on pumpkin plants, regardless of drift rate, although pumpkin plant growth and responses were minimal at the drift rates evaluated. Our results indicated that typical dicamba drift rates cause minimal dicamba injury on pumpkin plants at 8- and 12-leaf growth stages with negligible effects on resulting yields. Pumpkin plant injury and stunting would most likely be observed at dicamba drift rates > 1 μg per 176.1 cm2 of leaf area, which converts to 0.62 g per ha. Pumpkins receiving dicamba drift at different growth stages appear to be less sensitive than some other crops, but a drift event at higher rates than those evaluated in this study may impact plant growth and yield. It is important to note that other pumpkin varieties or other Cucurbita species not evaluated in this study may be more susceptible. Producers using dicamba in soybean rotations that are near pumpkin fields should spray under proper wind, temperature, and humidity conditions to best mitigate the occurrence of any drift events. Nomenclature: 3,6-dichloro-2-methloxybenzoic acid, Cucurbita pepo, C. moschata, dicamba, pumpkin.

No description available.