Actualmente en la ciudad de Lima existe un número limitado de edificios de gran altura. Por lo que no existe mucha literatura de este tipo de edificaciones en Perú. Los códigos peruanos se enfocan en edificios de mediana y baja altura. Por ello, se requiere realizar estudios más detallados para analizar y diseñar de forma más adecuada estas edificaciones altas según la realidad del país. En el presente artículo, se desarrollará el análisis modal pushover a 6 tipos de edificaciones de concreto armado de 35 niveles en la ciudad de Lima. Se plantea 3 modelos de edificación con distinto sistema estructural y con diferentes plantas (cuadrada y rectangular), siendo las áreas de 29m x 29m y 52m x 26m respectivamente. Estos sistemas estructurales son de núcleo rígido y pórticos con sistema de disipación de energía (amortiguadores de fluido viscoso y disipadores SLB) con objetivo de estudiar su comportamiento frente a solicitaciones sísmicas. Estas edificaciones se establecieron en función de los criterios y requerimientos de los códigos vigentes en el país, como también, distribución de la planta de edificaciones comúnmente usadas para oficinas y viviendas. Se encontró que los periodos naturales oscilan entre 2.6 a 3.3 segundos para edificios de núcleo rígido, se presenta un incremento para los edificios de amortiguamiento viscoso de 4.2 a 5.4 segundos y también para los de dispositivos SLB oscilan en un rango de 3.7 a 4.6 segundos. Se realizó, a su vez, un análisis no lineal estático modal para obtener las curvas de capacidad para cada tipo de edificación, las cuales fueron comparadas con las demandas sísmicas según las provisiones de diseño de la norma peruana sísmica E.030 y un promedio de espectros de registros de aceleraciones de eventos sísmicos severos en Perú y escalados en un rango de 0.2T a 1.5T. Finalmente, se determinó los puntos de desempeño para cada caso de edificación siguiendo las metodologías del ATC-40 encontrando que los edificios altos con núcleo rígido presentan aproximadamente el doble de rigidez que los edificios con sistema de disipación de energía, como también, presentan poca ductilidad a diferencia con los edificios con disipadores que presentan una larga ductilidad. / Currently in Lima city there is a limited number of high-rise buildings. So, there isn’t much literature on this type of building in Peru. Peruvian codes focus on medium and low-rise buildings. Therefore, more detailed studies are required to analyze and design these tall buildings more appropriately according to the reality of the country. In this thesis, the modal pushover analysis of 6 types of 35-story reinforced concrete buildings in Lima city will be developed. Three building models with different structural system and with different plan (square and rectangular) are proposed, being their areas of 29m x 29m and 52m x 26m respectively. These structural systems are rigid core and frames with an energy dissipation system (viscous fluid dampers and SLB dissipators) in order to study their behavior against seismic stresses. These buildings were established based on the criteria and requirements of the current codes in the country, as well as, the distribution of the floors of buildings commonly used for offices and homes. Natural periods were found to range from 2.6 to 3.3 seconds for rigid core buildings, there is an increase for viscous damping buildings from 4.2 to 5.4 seconds and also for SLB devices to range from 3.7 to 4.6 seconds. In turn, a modal static nonlinear analysis was performed to obtain the capacity curves for each type of building, which were compared with the seismic demands according to the design provisions of the Peruvian seismic code E.030 and an average of spectra of acceleration records of severe seismic events in Peru and scaled in a range of 0.2T to 1.5T. Finally, the performance points for each building case were determined following the ATC-40 methodologies, finding that tall buildings with a rigid core have approximately twice the stiffness of buildings with an energy dissipation system, as well as having low ductility. unlike buildings with dissipators that have long ductility. / Tesis

Die Anwendung von textilbewehrtem Beton ermöglicht vorgefertigte, filigrane und leichte Betonkonstruktionen von hoher Dauerhaftigkeit und Oberflächenqualität. Stand der Technik in der Anwendung sind hinterlüftete Fassadenplatten mit Dicken von 20-35 mm und Größen von bis zu 12,3 m², die aufgrund der geringen Querschnittssteifigkeiten nur mit metallischen oder monolithischen Aussteifungen realisierbar sind. Steife, tragfähige und dennoch leichte Querschnitte lassen sich mit Sandwichkonstruktionen erreichen, die große Spannweiten und zusätzliche Einsparpotentiale im Betoneinsatz und der Gesamtbauteilstärke ermöglichen. Insbesondere selbsttragende Sandwichkonstruktionen bieten ein hohes Anwendungspotenzial im Fassadenbereich. Der vorliegende Beitrag berichtet über Lastannahmen, Tragverhalten, Herstellung und Anwendung beim Hallenneubau des Instituts für Textiltechnik, RWTH Aachen.

Pour mieux comprendre et traiter les troubles musculosquelettiques présents à l’épaule, une meilleure connaissance de la contribution et de la fonction de chaque muscle de l’articulation glénohumérale est nécessaire. L’analyse des forces musculaires et articulaires est une étape importante pour comprendre les mécanismes de blessures et les pathologies. Ces forces musculaires peuvent être estimées de façon non invasive grâce à des modèles musculosquelettiques. Le défi est de prédire de façon physiologique les trajectoires musculaires et les bras de levier afin de s’assurer d’avoir une cohérence des forces musculaires dans les modèles musculosquelettiques. L’objectif de cette thèse était d’améliorer la géométrie musculaire des modèles musculosquelettiques de l’épaule en passant par plusieurs méthodes différentes d’implémentation des trajectoires musculaires. À cet égard, nos objectifs spécifiques étaient de : (1) améliorer la géométrie musculaire des modèles multicorps rigides grâce à l’implémentation de contraintes transverses; (2) évaluer la fiabilité d’un modèle éléments finis pour l’estimation des bras de levier et (3) tester la sensibilité de la prédiction des bras de levier aux incertitudes sur les zones d’insertions musculaires; (4) établir une base de données de bras de levier 3D pour des mouvements de grande amplitude; (5) quantifier de façon expérimentale les changements architecturaux des muscles entre l’état au repos et différents niveaux de contraction isométrique. (1) Deux modèles multicorps rigides de la coiffe des rotateurs ont été développés : un modèle classique intégrant une représentation des lignes d’action en 1D et un modèle possédant des contraintes transverses entre les lignes d’action permettant une représentation 2D. La représentation 2D avec des contraintes transverses permet une représentation plus physiologique des trajectoires musculaires et des bras de levier que les modèles classiques 1D. Toutefois, lors de mouvement allant au-delà de 90° d’élévation du bras, lorsque les points d’origine et d’insertion se rapprochent, les bras de levier et les longueurs musculaires sont mal estimés, car le modèle ne prend pas en compte les déformations du volume musculaire. (2) Un modèle éléments finis a été développé à partir de données d’imagerie médicale. Ce modèle permet une estimation des bras de levier fidèle aux données d’IRM. Contrairement aux modèles multicorps rigides, notre modèle élément finis rend compte du fait qu’un même muscle peut avoir plusieurs actions selon la position de sa ligne d’action par rapport au centre de rotation de l’articulation. (3) Le modèle a également servi à faire une étude de sensibilité des bras de levier : les zones d’insertion des différents muscles de la coiffe des rotateurs et du deltoïde ont été déplacées et les bras de levier associés calculés. Les résultats montrent qu’une variation de 10 mm des points d’insertion sur la tête humérale peut amener un muscle à changer de fonction (par exemple adduction plutôt que d’abduction). (4) Une collecte de données expérimentales effectuées sur quatre épaules a permis de collecter les bras de levier du deltoïde et des muscles de la coiffe des rotateurs pour des mouvements de grande amplitude. Ces résultats permettent de mieux comprendre le rôle des muscles de l’articulation glénohumérale lors de la réalisation de différents mouvements. Le deltoïde antérieur a une grande action en flexion et en adduction; le deltoïde moyen est un fort abducteur; le deltoïde postérieur agit en extension. Contrairement au deltoïde, l’infra-épineux et le petit rond ont principalement une fonction de rotateur externe. (5) Une collecte de données impliquant 14 sujets a été réalisée dans le but de quantifier les changements de géométrie musculaire et d’angle de pennation associés à la contraction pour les muscles du biceps, triceps et deltoïde. Les angles de pennation ont été obtenus grâce à un système d’échographie et les changements de géométrie externe des muscles ont été mesurés grâce à un capteur de structure. Les résultats montrent que les changements architecturaux pour les muscles étudiés se produisent principalement entre 0 et 25% de contraction maximale volontaire (aucune différence significative observée entre 25 et 50%). Le muscle le plus affecté par les changements architecturaux est le biceps. Cette thèse a évalué différentes approches de modélisation de la géométrie musculaire : l’approche la plus bio-fidèle étant finalement la modélisation par éléments finis, car elle permet de prendre en compte les interactions entre les structures et les déformations musculaires. De plus, nous avons montré l’importance d’estimer avec rigueur les paramètres d’entrée (zones d’insertions musculaires) des modèles et de bien évaluer la bio-fidèlité des modèles développés avant de les utiliser dans des contextes cliniques. Dans ce but, de nouvelles données ont été acquises en termes de déformations musculaires et d’angle de pennation pour permettre l’évaluation de modèle intégrant de l’activation musculaire. / Understanding and treating musculoskeletal disorders of the shoulder requires additional knowledge of the contribution and function of each muscle of the glenohumeral joint. The analysis of muscle and joint forces is an important step in understanding injury mechanisms and pathologies. These muscle forces can be estimated non-invasively using musculoskeletal models. The challenge is to physiologically predict muscle trajectories and moment arms to ensure consistency of muscle forces in musculoskeletal models. The aim of this thesis was to improve muscle geometry in musculoskeletal models of the shoulder by testing several different techniques for implementing muscle trajectories. Our specific objectives were to: (1) improve muscle geometry of rigid multibody models by using transverse constraints; (2) assess the reliability of a finite element model for estimating moment arms and (3) evaluate the sensitivity of moment arm predictions to uncertainties in muscle insertion areas; (4) create a database of 3D moment arms for movements with high ranges of motion; (5) experimentally quantify muscles’ architectural changes between resting state and different levels of isometric contractions. (1) Two rigid multibody models of the rotator cuff were developed: a classic model representing muscles with lines of action in 1D and a 2D model with transverse constraints between lines of action of a single muscle. The 2D model (with transverse constraints) gives a more physiological representation of muscle trajectories and moment arms than the classical 1D model. However, for arm movements beyond 90° of elevation, when the origin and insertion points get closer, moment arms and muscle lengths are misestimated due to the mode’s inability to account for muscle volume deformations. (2) A finite element model of the glenohumeral joint was developed based on medical imaging. Moment arms were computed and compared to the literature and MRI data. Our finite element model produces moment arms consistent with the literature and MRI data. Unlike rigid multibody models, our finite element model accounts for the fact that one muscle can have several actions depending on the position of its line of action relative to the centre of rotation of the joint. (3) The model was used to study moment arm sensitivity: insertion areas of rotator cuff muscles and the deltoid were moved, and associated moment arms have been computed. Results showed that a 10 mm variation in insertion points on the humeral head could cause a muscle to change function (for example performing adduction rather than abduction). (4) The 3D moment arms were assessed on four post-mortem human surrogates during movements with high ranges of motion. Results of the study gave us a better understanding of muscle functions during different movements. The main findings of the study were that the anterior deltoid was the largest flexor and had an adduction component, the median deltoid was a strong abductor, and the posterior deltoid acted in extension. Unlike the deltoid, the infraspinatus and teres minor were the largest external rotators of the shoulder. (5) Experimental measurements were performed on 14 subjects in order to quantify changes in muscle geometry and pennation angles associated with different levels of contraction for the biceps, triceps and deltoid. Pennation angles were measured on subjects using a portable ultrasound system. External muscle deformations were measured with an iPad equipped with a structure sensor. Changes in muscle architecture for the biceps, triceps and deltoid during isometric contractions occurred mostly between 0 and 25% of maximal voluntary contraction (no significant difference was observed between 25 and 50%). Changes were higher for the biceps than other muscles. This thesis evaluated different approaches to model muscle geometry: the approach leading to the most physiological result was the finite element model due to modeling of the interactions between structure and muscle deformations. Additionally, we demonstrated the importance of rigorously estimating input parameters (muscle insertion areas) and of properly evaluating the bio-fidelity of the models developed before using them in clinical contexts. New data was acquired regarding muscle deformations and pennation angles to evaluate models integrating muscle activation.

La cantidad de residuos se ha incrementado con el paso del tiempo, siendo actualmente una amenaza grave para el medio ambiente; tal es el caso del vidrio, además también el sector construcción aporta mucho a la contaminación ambiental, un sector que va a seguir en crecimiento constante. Uno de los sectores constructivos que va a crecer mucho más con el paso del tiempo son las vías. En nuestro país la mayoría de carreteras pavimentadas son de asfalto caliente, componente que contamina mucho y necesita mucho mantenimiento, es por eso que esta investigación planteo el uso masa común de los pavimentos rígidos, porque son más eco amigables, más resistentes y mucho más baratos a largo plazo, pero el inconveniente que se tiene con estos pavimento es su uso masivo de cemento componente que contamina mucho en su elaboración, es por eso que para hacer más sostenible con el medio ambiente se ha reemplazado parte del cemento y agregado fino para obtener un concreto ecológico que funciona adecuadamente para pavimentos rígidos, los reemplazos del cemento fueron de 20. 15 y 10%, del agregado fino fueron 15, 10 y 5% porcentajes obtenidos de la investigación de otros resultados, siendo estos los más favorables mecánicamente, los resultados obtenidos arrojan que un concreto con 15% de remplazo funciona correctamente, además reduce costos de realización y disminuye en un 11% la emisión de CO2 respecto de un concreto convencional. / The amount of waste has increased over time, currently being a serious threat to the environment; Such is the case of glass, and the construction sector also contributes a lot to environmental pollution, a sector that will continue to grow constantly. One of the construction sectors that will grow much more with the passage of time are the roads. In our country, most of the paved roads are made of hot asphalt, a component that pollutes a lot and needs a lot of maintenance, that is why this research proposed the common use of rigid pavements, because they are more eco-friendly, more resistant and much cheaper in the long term, but the disadvantage that these pavements have is their massive use of component cement that pollutes a lot in its preparation, that is why to make it more sustainable with the environment, part of the cement and fine aggregate have been replaced to obtain an ecological concrete that works adequately for rigid pavements, the cement replacements were 20, 15 and 10%, of the fine aggregate were 15, 10 and 5%, percentages obtained from the investigation of other results, these being the most favorable mechanically, the The results obtained show that a concrete with 15% replacement works correctly, also reduces production costs and reduces the e by 11%. CO2 mission compared to conventional concrete. / Tesis

<p>Pathogenic bacteria are evolving to drug resistant strains at alarming rates. The threat posed by drug resistant bacterial infections emphasize the need to establish new antimicrobial agents. Of immediate concern regarding the dangers of antibiotic resistance is the existence of intracellular bacteria, which find refuge from bactericidal devices by hiding within mammalian cells. Unfortunately, many therapeutics, such as vancomycin, do not possess membrane penetrating abilities to achieve efficacious eradication of bacteria at the subcellular level, allowing infections to persist. In an effort to target pathogens that thrive within mammalian cells, features of cell penetrating peptides (CPPs) and antimicrobial peptides (AMPs) were combined to develop a dual action antimicrobial CPP, cationic amphiphilic polyproline helices (CAPHs). CAPHs have proven to be an effective antimicrobial agent to combat an array of both Gram negative and Gram positive bacteria. </p> <p> </p> <p>Herein, to improve CAPHs activity, we have demonstrated how the incorporation of strategic modifications has resulted in increased cell uptake, alternative subcellular locations for CAPHs, and advanced antimicrobial potency. By simultaneously extending the helical length of CAPHs while incorporating different hydrophobic groups in place of the original isobutyl moiety that compose CAPHs we have created a <b>FL-P17-5R </b>series of peptides with five carbon aliphatic motifs: <b>Fl-P17-5B</b>, <b>Fl-P17-5C</b> and <b>Fl-P17-5L. </b>Through these modifications the peptides proved to be 2 to 5-fold more efficient in accumulating in macrophage cells than parent peptide Fl-P14LRR and where able to clear intracellular pathogenic bacteria, such as <i>Listeria</i>, from infected macrophages by 26 to 54%. </p> <p> </p> <p>In addition to making the <b>Fl-P17-5R</b> series of CAPHs to potentiate CAPHs activity, modifications to the cationic moiety of CAPHs were explored. By incorporating a new cationic monomer into the CAPHs sequence, a guanylated amino proline (GAP) residue, we produced <b>Fl-P14GAP</b>, a CAPHs peptide with an organized cationic charge display. This modification resulted in a 5-fold increase in cell uptake and a 2 to 16-fold decrease in minimum inhibitory concentration (MIC) values against strains of enteric and ESKAPE pathogens in comparison to Fl-P14LRR. <b>Fl-P14GAP</b> also executed superior clearance of intracellular pathogenic bacteria that resulted in the complete eradication of a drug resistant strain of <i>A. baumannii</i> from infected macrophage cells. Overall, our efforts with the <b>Fl-P17-5R</b> series of CAPHs and <b>Fl-P14GAP</b> have strengthened the therapeutic potential of CAPHs in the hopes of addressing the need for novel antibiotics with the propensity to eradicate intracellular pathogens.</p>

<p>Proteins are significant components of living cells. They perform a diverse range of biological functions such as cell shape and metabolism. The functions of proteins are determined by their three-dimensional structures. Cryogenic-electron microscopy (cryo-EM) is a technology known for determining the structure of large macromolecular structures including protein complexes. When individual atomic protein structures are available, a critical task in structure modeling is fitting the individual structures into the cryo-EM density map.</p> <p>In my research, I report a new computational method, MarkovFit, which is a machine learning-based method that performs simultaneous rigid fitting of the atomic structures of individual proteins into cryo-EM maps of medium to low resolution to model the three-dimensional structure of protein complexes. MarkovFit uses Markov random field (MRF), which allows probabilistic evaluation of fitted models. MarkovFit starts by searching the conformational space using FFT for potential poses of protein structures, computes scores which quantify the goodness-of-fit between each individual protein and the cryo-EM map, and the interactions between the proteins. Afterwards, proteins and their interactions are represented using a MRF graph. MRF nodes use a belief propagation algorithm to exchange information, and the best conformations are then extracted and refined using two structural refinement methods. </p> <p>The performance of MarkovFit was tested on three datasets; a dataset of simulated cryo-EM maps at resolution 10 Å, a dataset of high-resolution experimentally-determined cryo-EM maps, and a dataset of experimentally-determined cryo-EM maps of medium to low resolution. In addition to that, the performance of MarkovFit was compared to two state-of-the-art methods on their datasets. Lastly, MarkovFit modeled the protein complexes from the individual protein atomic models generated by AlphaFold, an AI-based model developed by DeepMind for predicting the 3D structure of proteins from their amino acid sequences.</p>

Internal combustion engines are used in many applications. The same engine type may have different components mounted to it depending upon its use. These engine mounted components need to be designed against fatigue in order to withstand the engine vibrations. Measured engine vibrations are commonly used as input data for fatigue estimation. The focus in this thesis is set on heavy-duty diesel engines, typically used in trucks, buses and industrial applications. All of the appended papers use engine vibration measurements to evaluate the proposed methods. In Paper A, the engine block motion is described with a seven degree of freedom kinematic model. These degrees of freedom consist of six rigid body modes and one assumed twisting degree of freedom. With this description, measured engine block vibrations can be used to accurately predict the vibration in positions that have not been measured. Relating the measured vibrations of an engine mounted component with the projected motion of the engine block at that same position, makes it possible to identify local dynamic phenomena. In Paper B, the kinematic model of Paper A is extended with three assumed bending deformation mode shapes. For the current engine type, all of the assumed deformation modes are ranked within the 10-300 Hz frequency range. The deformation mode of highest importance is the engine block twist. Including bending deformation increases the accuracy of the engine block vibration description but it also increases the demands on instrumentation. In Paper C, the possibility to modify measured engine vibration signals, for addition or removal of engine mounted components, is investigated. For this purpose, engine vibration measurements were performed with and without a 29 kg brake air compressor mounted to the engine. For the task of removing the effect that this engine mounted component has on the engine block, the two cases of knowing, and not knowing the vibration of the component are both considered. The proposed methodology successfully predicts the changes in engine vibration due to system modification. The proposed method can also be used to estimate the time response of a component's centre of gravity. In this study the component's dynamic properties are derived from measurements but they could also be produced using finite element analysis. This can be useful early in the design process to find critically stressed areas due to base excitation. / <p>QC 20171222</p>

[pt] As ligações estruturais desempenham um papel fundamental no comportamento global das estruturas de aço. Muitos ensaios experimentais desta ligações têm sido desenvolvidos para que se possa avaliar corretamente a influência dos parâmetros físicos e geométricos que influenciam no comportamento destas ligações. Hoje em dia, as ligações no eixo de menor inércia da coluna de pórticos contraventados são dimensionadas como flexíveis. Maiores problemas ocorrem quando este contraventamento não é possível e as ligações rígidas são utilizadas. Todavia, garantir que esta ligação tenha um comportamento rígido, principalmente no eixo de menor inércia, é algo um tanto quanto discutível. Sendo assim, a utilização de ligações semi-rígidas tornou-se viável porque tem um comportamento estrutural que melhor se aproxima da realidade e ainda possibilita uma diminuição do preço final da estrutura. Este trabalho apresenta uma avaliação do comportamento estrutural de ligações viga-coluna em estruturas de aço no eixo de menor inércia. Uma investigação dos modelos existentes de ligações semi- rígidas na literatura foi realizada e identificou dois modelos estruturais fundamentais para esta investigação: o de Kishi e Chen para o eixo de maior inércia e o de Teixeira Gomes para a menor inércia. Os sistemas de classificação de ligações existentes foram avaliadas mas ainda não se tem conhecimento de um sistema específico para o eixo de menor inércia ou da validade do uso dos sistemas de classificação gerados para maior inércia quando aplicados na menor inércia. Uma análise experimental onde três ensaios de ligação de aço viga x coluna, em escala real foi executada. Esta análise possibilitou a determinação da curva momento x rotação, resistência a flexão da ligação, evolução das tensões e deformações e possíveis modos de ruína. O presente trabalho também propõe um modelo preliminar de ligação semi-rígida com dupla cantoneira de alma e cantoneira de apoio, ou enrijecedor, no eixo de menor inércia visando sua utilização em edificações de estruturas de aço. Uma validação deste modelo preliminar foi realizada através de uma comparação com os resultados experimentais gerados. / [en] Connections perform a fundamental hole in the steel structure´s global behaviour. In order to evaluate the real influence of the physical and geometrical parameters that controls their behaviour, many experimental tests and analysis have been developed but a definitive answer to the problem in question still stands. Nowadays, the non-sway portal frame design still adopts bolted flexible connections in the column´s minor axis. Unfortunately, in the case of sway frames, the majority of connections are rigid, despite the fact that rigid connections have higher costs and rigid connections in the column minor axis have questionable true behaviour. To overcome these difficulties the use of semi-rigid connections can decrease the global structure cost, having an extra advantage of being closer to reality. This background served as motivation for the present investigation on the an evaluation of the structural behaviour of beam-column semi-rigid steel connections working in the column minor axis. A literature survey on the semi-rigid models currently in use in literature was accomplished. Two fundamental structural models were identified: the Kishi and Chen model for the bending on the column major axis and the model proposed by Gomes for the minor axis bending. A specific connection classification system developed for the major axis for the column minor axis was not found in the literature. The use of general classification for this task still deserves a validations study. An experimental programme consisting of three full scale tests of beam to column connections was carried out. This analysis enable the assessment of the moment versus rotation curve, moment capacity of the connection, stress patterns, strains and collapse mechanisms. This work also presents a preliminary semi-rigid model for the column´s minor axis, made with a double web angle and a support angle or a stiffner. A validation study of this preliminary model was accomplished through a comparison with the acquired experimental results. / [es] Las ligaduras extructurales desempeñam un papel fundamental en el comportamiento global de las extructuras de acero. Muchos ensayos experimentales han sido desarrollados para poder evaluar correctamente la influencia de los parámetros físicos y geométricos que influeyen en el comportamiento de estas ligaduras. Hoy en dia, las ligaduras en el eje de menor inercia de la columna de pórticos contraventados son dimensionadas como flexíbles. Mayores problemas ocurren cuando este contraventamento no es posible y se utilizan ligaduras rígidas. Pero garantizar que esta ligadura tenga un comportamiento rígido, principalmente en el eje de menor inercia, es algo bastante discutible. Así, la utilización de ligaduras semi-rígidas se hizo posible, porque tiene un comportamiento extructural que se aproxima mejor de la realidad y posibilita una diminuición del precio final de la extructura. Este trabajo presenta una evaluación del comportamiento extructural de ligaduras viga-columna en extructuras de acero en el eje de menor inercia. Se realizó una investigación de los modelos existentes de ligaduras semirígidas en la literatura y se identificó dos modelos extructurales fundamentales para esta investigación: el de Kishi y Chen para el eje de mayor inercia y el de Teixeira Gomes para el de menor inercia. Los sistemasde clasificación de ligaduras existentes fueron evaluados pero aún no se tiene conocimiento de un sistema específico para el eje de menor inercia o de la validad del uso de los sistemasde clasificación generados para mayor inercia cuando aplicados en menor inercia. Un análisis experimental donde tres ensayos de ligadura de acero viga x columna, en escala real fue ejecutada. Este análisis posibilitó la determinación de la curva momento x rotación, resistencia a la fexión de la ligadura, evolución de las tensiones y deformaciones y posibles modos de ruína. El presente trabajo propone un modelo preliminar de ligadura semirígida con dupla esquinera de alma y de apoyo, o enrijecedor, en el eje de menor inercia con el objetivo de utilizarlo en edificaciones de extructuras de acero. Una evaluación de este modelo preliminar fue realizada através de una comparación con los resultados experimentales generados.

CATD was not only adequate for analyzing the pursuit of erratically moving prey but also worked well when analyzing the pursuit of prey that remained stationary. It cannot be fully concluded that bats utilize the CATD strategy to successfully capture erratically flying prey. The angle remains relatively constant but does not exhibit a zero change in angle as by definition. The large forces experienced by the bat were seen when the bat began to rotate its body about its pitch axis or when the bat made a large turn. Moments were seen specifically when the bat began to bank into its last and final turn towards its target.; Digital recordings of three different species of bats were studied in this thesis to determine the forces and moments that were experienced throughout the bat's flight. The recordings were also studied to determine the pursuit strategies that were most effective for the bat to quickly capture its prey. A pursuit strategy is a strategic way to travel that will allow a pursuer to capture/approach their target the quickest. Therefore when a bat utilizes a particular pursuit strategy, it will adjust its position/ direction vector in a particular way that will allow it to approach its target very quickly. Data was collected directly from the video by manual collection utilizing Microsoft Visual Studio to extract frames, collect and record the data. This research was conducted to determine when throughout the flight the bat would experience significant forces and moments. The location and magnitude of the forces were reported along with an explanation of why the bat was experiencing a peak at each specific time. The forces and moments that the bat experienced thought-out the flight pursuit were calculated by relative velocity and acceleration calculations. In all four scenarios the bat experienced forces in relation to rotating its body about its center of mass. Forces were specifically seen when the bat periodically began to rotate its body before the final plunge to capture its prey. Prey avoidance and pursuit strategies were also studied and observed in this thesis which included the constant bearing and the constant absolute target direction. The intent was to determine which pursuit strategy bats use to quickly capture their prey. The constant bearing strategy is utilized to pursue prey moving along a smooth path, on the other hand the Constant Absolute Target Direction (CATD) pursuit strategy is utilized to capture erratically moving prey. For most of the bats analyzed, it was seen that the CATD strategy proved to be the preferred pursuit strategy.

No description available.