Geothermal heating in the Panama Basin. Part II: abyssal water mass transformation

Diabatic upwelling of abyssal waters is investigated in the Panama Basin employing the water mass transformation framework of Walin [1982]. We find that, in large areas of the basin, the bottom boundary layer is very weakly stratified and extends hundreds of meters above the sea floor. Within the weakly stratified bottom boundary layer (wsBBL) neutral density layers intercept the bottom of the basin. The area of these density layer incrops increases gradually as the abyssal waters become lighter. Large incrop areas are associated with strong diabatic upwelling of abyssal water, geothermal heating being the largest buoyancy source. While a significant amount of water mass transformation is due to extreme turbulence downstream of the Ecuador Trench, the only abyssal water inflow passage, water mass transformation across the upper boundary of abyssal water layer is accomplished almost entirely by geothermal heating

Viabilidade econômica agrícola e responsabilidade ambiental em unidades rurais de produção orgânica e convencional em Mundo Novo, MS.

bitstream/item/69064/1/099-recalde-viabilidade.pdfPublicado também no Cadernos de Agroecologia, v. 7, n.2, 2012

Geothermal heating in the Panama Basin. Part I: hydrography of the basin

The Panama Basin serves as a laboratory to investigate abyssal water upwelling. The basin has only a single abyssal water inflow pathway through the narrow Ecuador Trench. The estimated critical inflow through the Trench reaches 0.34 ± 0.07 m s−1, resulting in an abyssal water volume inflow of 0.29 ± 0.07 Sv. The same trench carries the return flow of basin waters that starts just 200 m above the bottom and is approximately 400 m deeper than the depth of the next possible deep water exchange pathway at the Carnegie Ridge Saddle. The curvature of temperature‐salinity diagrams is used to differentiate the effect of geothermal heating on the deep Panama Basin waters that was found to reach as high as 2200 m depth, which is about 500 m above the upper boundary of the abyssal water layer

Passive acoustic monitoring of baleen whales in Geographe Bay, Western Australia

Baleen whales were monitored in Geographe Bay, Western Australia between 2008 and 2011 using passive acoustics. We aimed to monitor migratory timing through Geographe Bay, characterise whale vocalizations, and estimate detection ranges of vocalising whales in different background noise conditions. The results indicated that humpback and blue whales migrated through Geographe Bay every year, however the frequency and timing of their vocalisations varied among years. Humpback whale songs changed in composition among years, but most energy was consistently between 200-500 Hz. Blue whale calls were those of the eastern Indian Ocean pygmy blue whale with low quasi-tonal sounds with harmonics ranging from 20-100 Hz and variable down-sweep impulses with frequencies decreasing from ~100 Hz to ~20 Hz. No significant changes in calls were observed among years. Based on a range independent propagation model, the detection range for vocalising pygmy blue whales was estimated to be between 6-8 km, and for humpback whales ~20-30 km. The prevalence of high levels of noise from vessel traffic affected the detection range significantly for passive acoustic monitoring, and would have also affected the capacity for whales to communicate and perceive important cues in their environment

Adaptive MPC of wind turbine with aero-elastically tailored blades

The use of aero-elastically tailored blades (ATB) for large wind turbines has shown the benefit of mitigating blade loads with the design of bend twist coupling (BTC) along the blades. In this work, to include the ATB effect into the turbine model for control, a twofold modeling for ATB characteristics is proposed. First a static BTC distribution is added to the turbine aerodynamics to account for the blade’s pre-bend-twist design, next a second order transfer function is introduced to approximate the blade structural dynamic response to wind speed variations. The nonlinear model of the whole ATB wind turbine is built up in Simulink, linearized and discretized into a state-space form. An adaptive model predictive controller (MPC) is developed, the control performance is compared to the gain-scheduling baseline controller

Model predictive control of wind turbine with aero-elastically tailored blades

The use of aero-elastically tailored blades (ATB) for large wind turbines has shown the benefit of mitigating blade loads, in a passive adaptive manner, with the design of bend-twist coupling (BTC) along the blades. The BTC design makes the blades torsionally flexible and capable of adapting to different wind speeds. However, such increased flexibility makes the turbine modeling computationally demanding and the real-time controller design more challenging. In this work, to include the ATB effect into the turbine model for control, a twofold modeling for ATB characteristics is proposed. First a static BTC distribution is added to the turbine aerodynamics to account for the blade’s pre-bend-twist design, next a second order transfer function is introduced to approximate the blade structural dynamic response to wind speed variations. The nonlinear model of the whole ATB wind turbine is built up in Simulink, linearized and discretized into a state-space form. A model predictive controller (MPC) is developed with the actuator constraints considered. Simulation studies are conducted on a 5MW ATB wind turbine at a selected above-rated wind speed. The use of the simplified model for control is assessed and the performance of MPC is compared to the gain-scheduling baseline controller

Restricted structure non-linear generalized minimum variance control of a 2-link robot arm

The objective of this paper is to propose a restricted structure non-linear generalized minimum variance (RS-NGMV) controller for a two-link robot arm. The NGMV control is a useful method for offering control solutions for nonlinear systems. The motivation is to provide the advantages of NGMV control inside a low-order controller structure with an intention to enable design simplicity and easy implementation for engineers with classical training. The result will be an optimal controller with simple tuning variables. Simulations of the RS-NGMV controller are presented using Matlab/Simulink

Análisis de las Negociaciones de Mercado de Carbono en la Bolsa de Valores en Ecuador

El presente ensayo  apunta, en primera instancia, a describir el funcionamiento y razón de ser del mercado de carbono, realizando un análisis de las implicaciones del Protocolo de Kioto mediante sus   tres mecanismos, cuyo objetivo principal es ofrecer medios para recortar los Gases de Efecto Invernadero, responsables del Cambio Climático; estos mecanismos son: Mecanismo para un Desarrollo Limpio (MDL), Mecanismo de Implementación Conjunta (IC) y el Comercio de Derechos de Emisión. A continuación, se realiza una descripción simplificada de cada uno de ellos, con el fin de conocer sus alcances, limitaciones y aplicabilidad en el Ecuador.   Finalmente, se analizará la Bolsa de Valores de Quito, su importancia, caracterí­sticas, quienes participan y su función económica.Con los elementos analizados anteriormente, se realizará entonces un análisis del Mercado de Carbono en la Bolsa de Valores de Ecuador así­   como la creación de un mercado de valores que promueva la Responsabilidad Social Empresarial (RSE), describiendo claramente lo que es el mercado de valores social y ambientalmente responsable, la estrategia de la Bolsa de Valores en el marco de la RSE, así­ como la promoción del Mercado de Carbono en Ecuador con todas y cada una de las estrategias a seguir.En otras palabras, la idea central de este ensayo  es analizar la   posibilidad de aprovechamiento de compraventa de certificados de carbono por medio de la Bolsa de Valores, motivando a las empresas del Ecuador para que participen en los procesos de negociación en los mercado de carbono y así­ generar una seguridad jurí­dica, lo que nos permite tener una visión más amplia de un emprendiendo en el   desarrollo social y económico del paí­s y al   mismo tiempo apostar a tecnologí­as limpias lo que conlleva a una gradual transición hacia una economí­a pos petrolera