1,786 research outputs found
Experimental Study of a Cascade of Low Pressure Turbine Blades with Upstream Periodic Stator Wakes
The objective of this study is to experimentally study film cooling flows. A closed-loop wind tunnel with a four passage linear cascade of US Air Force Research Laboratory (AFRL) ultra-high-lift L1A low pressure turbine (LPT) blades and upstream wake generator is used in conjunction with Particle Image Velocimetry (PIV) flow visualization technique to study turbulent film cooling flows due to the interaction between vanes and blades. Further post-processing in the form of Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD) modal analyses is performed to determine the relevant modes that characterize the coherent structures in the flow. An image patching algorithm is also implemented. The results obtained are used to characterize the periodic wake on the cascade flow. The periodic wake has been studied in detail near the leading edge of the suction side. The velocity data led to the mean velocity profile and maximum velocity deficit in the wake. The POD identified the most energetic modes representing the vortex shedding wavelength, and its harmonics, of the wake generator plates. The DMD confirmed the wake passage frequency. Implementation of the image patching algorithm with four domains was presented. The technique was successful in computing the average vector field. Further downstream of the leading edge, the POD modes are shown to become more chaotic and less energetic. The leading order mode pair loses close to half of their energy to lower order modes due to the cascading of turbulent kinetic energy to lower spatial scales and to viscous dissipation losses. When the wake is impinging on the leading edge, the boundary layer separates near the transition point. The boundary layer remains completely attached to the trailing edge when the wake is not impinging on the leading edge
Hemispheric differences in semantic cognition and their contribution to behaviour
This thesis investigated hemispheric differences in semantic cognition and their contribution to behaviour, using resting-state and task-based fMRI in conjunction with automated meta-analyses and cognitive decoding. The controlled semantic cognition framework proposes that distinct brain regions support the long-term representation of heteromodal conceptual knowledge and semantic control processes that retrieve currently-relevant aspects of knowledge. However, previous studies have not investigated whether these components have distinct patterns of lateralisation. Chapter 2 assessed intrinsic connectivity of four regions implicated in semantic cognition: anterior temporal lobe, angular gyrus, inferior frontal gyrus, and posterior middle temporal gyrus. Semantic sites in the left hemisphere showed connectivity with both control regions and default mode network, whilst their right hemisphere homotopes showed connectivity with control regions and visual and attentional systems. Semantic control regions showed the strongest lateralisation. Chapter 3 examined hemispheric specialisation of the anterior temporal lobes, strongly implicated in semantic representation. It assessed the relationship between differential intrinsic connectivity and behaviour outside the scanner on a semantic categorisation task previously shown to be sensitive to lateralisation. Graded differences in connectivity between left and right anterior temporal lobes, and from right anterior temporal cortex to the visual system related to semantic efficiency. Finally, Chapter 4 tested the specificity of the semantic control system and its relationship to domain-general control. Using a task known to engage domain-general inhibition, but introducing semantic content, this chapter yields evidence that regions implicated in semantic control are not sensitive to challenging tasks that require exercising controlled processing, and instead are specific to semantic processing. Together, these results constitute evidence for a component-process architecture in the semantic cognition system, with different patterns of lateralisation for the semantic representation and control systems. Within these systems, the results confirm the specific nature of semantic control, and fit with the graded-hub architecture of semantic representation
Políticas de apoyo a la productividad de la microempresa informal ¿dónde está México?
En forma tradicional se ha considerado, tanto desde la perspectiva teórica de las ciencias sociales como de su praxis política, a la microempresa informal como un lastre para el desarrollo. Sin embargo, desde hace algunos años, un sector de la literatura especializada ha presentado evidencia de que, a pesar de su baja productividad, la contribución de la economía informal 2 como generadora de empleo y de ingreso a la economía de los países menos desarrollados es significativa. Dado que otros países han comenzado a desarrollar políticas para incentivar la productividad en el sector informal, el propósito principal del presente trabajo es entender, a través de la revisión de los reglamentos de apoyo a las microempresas y nuevos decretos y reglamentación, la posición actual de México en este debate
SinEx DB: a database for single exon coding sequences in mammalian genomes
Indexación: Web of Science.Eukaryotic genes are typically interrupted by intragenic, noncoding sequences termed introns. However, some genes lack introns in their coding sequence (CDS) and are generally known as 'single exon genes' (SEGs). In this work, a SEG is defined as a nuclear, protein-coding gene that lacks introns in its CDS. Whereas, many public databases of Eukaryotic multi-exon genes are available, there are only two specialized databases for SEGs. The present work addresses the need for a more extensive and diverse database by creating SinEx DB, a publicly available, searchable database of predicted SEGs from 10 completely sequenced mammalian genomes including human. SinEx DB houses the DNA and protein sequence information of these SEGs and includes their functional predictions (KOG) and the relative distribution of these functions within species. The information is stored in a relational database built with My SQL Server 5.1.33 and the complete dataset of SEG sequences and their functional predictions are available for downloading. SinEx DB can be interrogated by: (i) a browsable phylogenetic schema, (ii) carrying out BLAST searches to the in-house SinEx DB of SEGs and (iii) via an advanced search mode in which the database can be searched by key words and any combination of searches by species and predicted functions. SinEx DB provides a rich source of information for advancing our understanding of the evolution and function of SEGs.https://academic.oup.com/database/article-lookup/doi/10.1093/database/baw09
Relación de las prácticas: preparación de suelo y lámina de agua en la presencia de arroz voluntario (Oriza sp) en la época de invierno en la Cooperativa Augusto César Sandino, Las Mangas - San Isidro ׀׀ Semestre 2016
El arroz voluntario (Oriza sp), es una especie de arroz considerada una amenaza
agronómica en la producción de semillas y siembras comerciales, debido a que se comporta
como una maleza que afecta la productividad del cultivo del arroz. La investigación se
realizó durante el ׀׀ Semestre 2016 en la Cooperativa Augusto César Sandino San Isidro
Matagalpa. Los objetivos fueron determinar las distintas prácticas de preparación de suelos
y láminas de agua utilizadas en la Cooperativa y su relación con la presencia de arroz
voluntario y el porcentaje encontrado. La investigación fue de naturaleza no experimental.
Las variables evaluadas fueron: preparación de suelo, lámina de agua, para evaluar estas
variables se empleó el instrumento de la encuesta y para la variables arroz voluntario se
procedió a realizar un muestreo el cual correspondía en seleccionar un punto al azar en al
lote seleccionado con una área de 1m², posteriormente se realizaba un transepto en forma
de W en la cual los puntos a muestrear estaban ubicados a 25m de distancia entre ellos, por
lote se establecieron 5 W realizando un total de 25 muestreos. Se determinaron 4 prácticas
de preparación de suelo en la Cooperativa y 2 distintos tipos de lámina de agua, teniendo
como resultado que la práctica con menor porcentaje de incidencia de arroz voluntario fue
la práctica 2 con el 1% de incidencia, mientras tanto el porcentaje total de los lotes
muestreados en la Cooperativa fue de un 3% de incidenci
Sketching for Real-time Control of Crowd Simulations
Controlling the behaviour of a crowd simulation typically involves tuning of a system's parameters through trial and error, a time-consuming process relying on knowledge of a potentially complex parameter set. Numerous graphical control approaches have been proposed to allow the user to interact with a simulation intuitively. This research investigates the use of a real-time sketch-based approach for crowd simulation control. This is done by modifying the environment of the simulation. Users can create entrances/exits, barriers and flow lines in real-time on top of an environment. This process requires a data structure to represent the environment and navigate the crowd through it. Two alternatives are presented: grid and navigation mesh. A detailed comparison shows that the navigation mesh is a more scalable approach since it uses less memory, has a similar pathfinding time, and is a better structure to represent the environment than the grid.
The thesis also presents extensions to the sketch-based approach in the form of novel control tools, including storyboards to define the journey of the crowd, a timeline interface to simulate events through the day, and a sketch-based group storyboard to link behaviours and paths to be followed by a group. These tools are used to create two complex scenarios to exemplify possible applications of the sketch-based approach. The work on timelines also raises a new problem for an approach that dynamically modifies an environment in real-time which is 'when does the crowd know about the change?' Some initial solutions to how this should be handled are presented.
The sketch-based system is evaluated by comparing it to a validated commercial system called MassMotion. The comparison takes into account the plausibility of the simulation and usability of the user interface. A user study is carried out to evaluate the graphical user interface of both systems. Formal evaluation methods are used to make the comparison: the benchmark suite 'steersuite', an adapted version of the Keystroke-Level Model (KLM) and the System Usability Scale (SUS). The results show that the sketch-based approach is faster and easier to use than MassMotion, but with fewer control options. An implementation of the sketching interface in a Virtual Reality environment is also considered. However, when compared to the desktop interface using a proposed adaptation to KLM for VR, the results show that sketching in a VR environment is slower and less accurate than the desktop version
El centro cívico como pieza urbana: Proyecto de centro cultural en el triángulo Bavaria
El siguiente documento tiene como finalidad mostrar el trabajo de investigación realizado durante el último año de la Maestría en Arquitectura de la Universidad Nacional. El documento presenta un proyecto arquitectónico sobre un centro cultural en el sector del Triángulo Bavaria, resuelto después de hacer un análisis de referentes urbanos y arquitectónicos para conseguir un producto final acorde a los análisis hechos. El documento está estructurado en tres secciones correspondientes a lo realizado durante los dos últimos semestres de la maestría. La primera sección corresponde al análisis del sitio y el planteamiento de un problema a resolver en un lugar determinado de Bogotá. La segunda sección presenta una serie de posibles soluciones que dependen de la exploración morfológica de un anteproyecto basado en las conclusiones de los análisis previos. La última sección dirigida a mostrar una solución resultado de los análisis y las morfologías experimentadas en el sitio, concluyendo con un proyecto arquitectónico. En consecuencia este documento sirve como muestra de lo aprendido en dos campos principales de la Maestría en Arquitectura. Primero con la investigación y análisis de referentes arquitectónicos, para identificar estrategias de diseño que serán utilizadas en la solución final. Y segundo en el proyecto arquitectónico poniendo a prueba lo identificado en la fase previa y confrontando lo analizado con el sitio y el problema, justificando todos los pasos realizados para conseguir el producto final. Finalmente este trabajo pretende mostrar las etapas realizadas durante la elaboración de un proyecto arquitectónico, creando estrategias que puedan ser replicadas sin importar el sitio o el proyecto a resolver. Palabras clave: industrial, centro cívico, reciclaje, cultural, equipamiento, vacío urbano.Abstract: The following document is intended to show the research work carried out during the last year of the master’s degree in architecture from the National University. The document presents an architectural project on a cultural center in the area of the triangle Bavaria, determined after making an analysis of references to get a final product according to analyses made architectural and urban. The document is structured into three sections corresponding to what has been done during the last two semesters of mastery. The first section corresponds to the site analysis and the approach of a problem to solve in a particular place in Bogota. The second section presents a series of possible solutions that rely on morphological scan of a first draft based on the conclusions of the previous analysis. The last section to show a result of the analysis solution and the morphologies experienced on the site, concluding with an architectural project. As a result this document serves as a demonstration of what they learned in two main fields architecture master’s degree. First with the research and analysis concerning architectural, to identify design strategies that will be used in the final solution. And second in the architectural project by testing identified in the previous phase and confronting it analyzed the site with the problem, justifying all made steps to achieve the final product. Finally this paper aims to show the stages performed during the development of an architectural project, creating strategies that can be replicated regardless of site or project to resolve. Keywords: industrial, civic center, recycling, culture, equipment, vacuum urban.Maestrí
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