400 research outputs found
Utilizing Modal Testing for Monitoring the Structural Health of Wind Tunnel Facility Hardware
The 10- by 10-Foot Abe Silverstein Supersonic Wind Tunnel (1010) is the largest and fastest wind tunnel facility at NASAs Glenn Research Center(GRC) and is specifically designed to test supersonic propulsion components from inlets and nozzles to full-scale jet and rocket engines[1]. Recently, a critical part of the wind tunnel failed and required a redesign before reintegrating into the facility. The design requirements of this new component required that clearances between large metallic components exist, which have the potential for undesirable nonlinear dynamics to occur, in particular rattling. Rattling is feared to occur when the wind tunnel is being operated in certain flow regimes that induce cyclic aero loads on the new component near its natural frequencies. This paper describes the approach taken to better understand and resolve this vibration problem using modal testing. A modal test was developed and executed by GRCs Structural Dynamics Lab to quantify the modal parameters of the structure, namely which specific excitation frequencies caused the structure to rattle. These results were shared with facility operators as frequency ranges that should be avoided to ensure maximum lifespan of the new structure. Additional means of structural health monitoring (SHM) as well as Vortex shedding are briefly discussed in this paper
Combined Qualification Vibration Testing and Fixed Base Modal Testing Utilizing a Fixed Based Correction Method
Vibration testing spaceflight hardware is a vital, but time consuming and expensive endeavor. Traditionally modal tests are performed at the component, subassembly, or system level, preferably free-free with mass loaded interfaces or fixed base on a seismic mass to identify the fundamental structural dynamic (modal) characteristics. Vibration tests are then traditionally performed on single-axis slip tables at qualification levels that envelope the maximum predicted flight environment and workmanship in order to verify the spaceflight hardware can survive its flight environment. These two tests currently require two significantly different test setups, facilities, and ultimately reconfiguration of the spaceflight hardware. The vision of this research is to show how traditional fixed-base modal testing can be accomplished using vibration qualification testing facilities, which not only streamlines testing and reduces test costs, but also opens up the possibility of performing modal testing to untraditionally high excitation levels that provide for test-correlated finite element models to be more representative of the spaceflight hardware's response in a flight environment. This paper documents the first steps towards this vision, which is the comparison of modal parameters identified from a traditional fixed-based modal test performed on a modal floor and those obtained by utilizing a fixed based correction method with a large single-axis electrodynamic shaker driving a slip table supplemented with additional small portable shakers driving on the slip table and test article. To show robustness of this approach, the test article chosen is a simple linear weldment, whose mass, size, and modal parameters couple well with the dynamics of the shaker/slip table. This paper will show that all dynamics due to the shaker/slip table were successfully removed resulting in true fixed-base modal parameters, including modal damping, being successfully extracted from a traditional style base-shake vibration test setup
Análisis de uniones de materiales compuestos en estructuras navales
El tfg consistirá en 2 fases que la detallaremos a continuación. la primera fase será el aprendizaje de la herramienta de cálculo que se utilizará a lo largo del proyecto. para ello se realizarán modelos sencillos, de los que se conozca la solución analítica, para poder compararlos con los resultados obtenidos con el programa de elementos finitos. en esta primera fase también se estudiará la base teórica sobre la que se fundamenta el programa de cálculo. en la segunda fase se analizarán numéricamente el comportamiento de las uniones de materiales compuestos. el material base a unir corresponde a un laminado de fibra de vidrio con una matriz de viniléster. la unión a analizar es encolada por solape. los resultados numéricos se compararán con resultados experimentales. esta comparación permitirá validar los modelos numéricos realizados. finalmente, se procederá a la redacción y la defensa del trabajo final de grado, que contendrá tanto la base teórica en la que se sustenta, como los distintos análisis numéricos realizados para analizar el comportamiento de las uniones estudiadas
Acompañamiento a la extensión rural: ganadería doble propósito en el municipio del Páramo, Santander.
El objetivo general de esta pasantía fue desarrollar un proceso integral desde lo técnico, social y ambiental, enfocado en la ganadería, con el propósito de adquirir destrezas en el área de extensión rural a través de FORUM LTDA en el municipio del Páramo Santander. Durante este proceso de pasantía, se tuvo interacción con el mundo laboral, con la población del sector agropecuario y profesionales del área; en cuanto a la comunidad, es satisfactorio trasmitir los conocimientos, al igual que también se obtiene un amplio aprendizaje de los productores agropecuarios a partir de su experiencia, que si bien en ocasiones pueden ir en contravía a los conceptos técnico, es necesario enriquecer el conocimiento a partir de las discrepancias, dado que, el conocimiento obtenido en la academia es importante, pero también lo es el que se obtiene del contacto diario con los escenarios y contextos reales que viven los productores, de modo que se buscó la manera de llegar a un empalme que integrara el conocimiento académico y el empírico, buscando siempre satisfacer las necesidades de la mejor manera, y llevando a cada finca no solo el conocimiento de las nuevas técnicas productivas que existen y las soluciones a diferentes problemas. El resultado de estos procesos de mejoramiento en ganadería se observa a largo plazo, y se espera que las asesorías y la inducción a la implementación de tecnología y nuevas prácticas permitan que se optimicen los sistemas que desarrollan los ganaderos, y se vean reflejados en un tiempo. A través del proceso diagnóstico, se logró identificar diversas problemáticas que
fueron atendidas, de igual modo, hubo un amplio enfoque en la asesoría respecto a la incorporación de mejores genéticas, la inseminación artificial y las buenas prácticas en la alimentación de los animales; al cierre del proceso, los beneficiados se mostraron agradecidos y satisfechos con el acompañamiento.Universidad Libre Seccional Socorro - Facultad de Ingenierías y Ciencias AgropecuariasThe general objective of this internship was to develop a comprehensive technical, social and environmental process, focused on livestock, with the purpose of acquiring skills in the rural extension area through FORUM LTDA in the municipality of Páramo Santander. During this internship process, there was interaction with the world of work, with the population of the agricultural sector and professionals in the area; Regarding the community, it is satisfactory to transmit knowledge, as well as extensive learning from agricultural producers based on their experience, which although sometimes may go against technical concepts, it is necessary to enrich the knowledge based on the discrepancies, since the knowledge obtained in the academy is important, but so is the knowledge obtained from the daily contact with the real scenarios and contexts that the producers live, so that a way was sought to arrive at a joint that will integrate academic and empirical knowledge, always seeking to satisfy the needs in the best way, and bringing to each farm not only the knowledge of the new productive techniques that exist and the solutions to different problems. The result of these improvement processes in livestock is observed in the long term, and it is expected that the advice and induction to the implementation of technology and new practices will optimize the systems developed by farmers, and will be reflected in time . Through the diagnostic process, it was possible to identify various problems that
They were attended, in the same way, there was a broad focus on advice regarding the incorporation of better genetics, artificial insemination and good practices in animal feeding; At the end of the process, the beneficiaries were grateful and satisfied with the accompaniment
Effects of the Brain Derived Neurotrophic Factor Val66met Polymorphism on the Structural and Functional Architecture of the Human Brain
Brain Derived Neurotrophic Factor (BDNF) is an important neurotrophin enabling
synaptogenesis at the dendrites of neurons. Several studies have implicated the Val66Met single nucleotide polymorphism of the BDNF gene as a factor affecting cortical thickness and resting-state functional connectivity (RSFC) of the human brain. In this thesis, I investigated the effects of Val66Met on cortical thickness and RSFC among individual cortical regions and at the level of large-scale functional networks in all genotype groups (Val/Val, Val/Met, Met/Met, and Met carriers). Cutting-edge techniques were used to individually localize anatomical and functional brain regions in a large sample of healthy young adults from the Human Connectome Project. A comprehensive series of analyses revealed no significant group differences in cortical thickness or RSFC across the brain. These results suggest that, contrary to previous reports, the Met allele does not confer differences in structural or functional integrity of the healthy young adult brain
Effects of the Brain Derived Neurotrophic Factor Val66met Polymorphism on the Structural and Functional Architecture of the Human Brain
Brain Derived Neurotrophic Factor (BDNF) is an important neurotrophin enabling
synaptogenesis at the dendrites of neurons. Several studies have implicated the Val66Met single nucleotide polymorphism of the BDNF gene as a factor affecting cortical thickness and resting-state functional connectivity (RSFC) of the human brain. In this thesis, I investigated the effects of Val66Met on cortical thickness and RSFC among individual cortical regions and at the level of large-scale functional networks in all genotype groups (Val/Val, Val/Met, Met/Met, and Met carriers). Cutting-edge techniques were used to individually localize anatomical and functional brain regions in a large sample of healthy young adults from the Human Connectome Project. A comprehensive series of analyses revealed no significant group differences in cortical thickness or RSFC across the brain. These results suggest that, contrary to previous reports, the Met allele does not confer differences in structural or functional integrity of the healthy young adult brain
SRG110 Stirling Generator Dynamic Simulator Vibration Test Results and Analysis Correlation
The U.S. Department of Energy (DOE), Lockheed Martin (LM), and NASA Glenn Research Center (GRC) have been developing the Stirling Radioisotope Generator (SRG110) for use as a power system for space science missions. The launch environment enveloping potential missions results in a random input spectrum that is significantly higher than historical radioisotope power system (RPS) launch levels and is a challenge for designers. Analysis presented in prior work predicted that tailoring the compliance at the generator-spacecraft interface reduced the dynamic response of the system thereby allowing higher launch load input levels and expanding the range of potential generator missions. To confirm analytical predictions, a dynamic simulator representing the generator structure, Stirling convertors and heat sources were designed and built for testing with and without a compliant interface. Finite element analysis was performed to guide the generator simulator and compliant interface design so that test modes and frequencies were representative of the SRG110 generator. This paper presents the dynamic simulator design, the test setup and methodology, test article modes and frequencies and dynamic responses, and post-test analysis results. With the compliant interface, component responses to an input environment exceeding the SRG110 qualification level spectrum were all within design allowables. Post-test analysis included finite element model tuning to match test frequencies and random response analysis using the test input spectrum. Analytical results were in good overall agreement with the test results and confirmed previous predictions that the SRG110 power system may be considered for a broad range of potential missions, including those with demanding launch environments
Chitosan and nematophagous fungi for sustainable management of nematode pests
Plants are exposed to large number of threats caused by herbivores and pathogens which cause important losses on crops. Plant pathogens such as nematodes can cause severe damage and losses in food security crops worldwide. Chemical pesticides were extendedly used for nematode management. However, due to their adverse effects on human health and the environment, they are now facing strong limitations by regulatory organisations such as EFSA (European Food Safety Authority). Therefore, there is an urgent need for alternative and efficient control measures, such as biological control agents or bio-based plant protection compounds. In this scenario, chitosan, a non-toxic polymer obtained from seafood waste mainly, is becoming increasingly important. Chitosan is the N-deacetylated form of chitin. Chitosan is effective in the control of plant pests and diseases. It also induces plants defence mechanisms. Chitosan is also compatible with some biocontrol microorganisms mainly entomopathogenic and nematophagous fungi. Some of them are antagonists of nematode pests of plants and animals. The nematophagous biocontrol fungus Pochonia chlamydosporia has been widely studied for sustainable management of nematodes affecting economically important crops and for its capability to grow with chitosan as only nutrient source. This fungus infects nematode eggs using hyphal tips and appressoria. Pochonia chlamydosporia also colonizes plant roots endophytically, stimulating plant defences by induction of salicylic and jasmonic acid biosynthesis and favours plant growth and development. Therefore, the combined use of chitosan and nematophagous fungi could be a novel strategy for the biological control of nematodes and other root pathogens of food security crops.This research was funded by PID2020-119734RB-I00 Project from the Spanish Ministry of Science and Innovation and by European Project H2020 MUSA no. 727624
Putative LysM Effectors Contribute to Fungal Lifestyle
Fungal LysM effector proteins can dampen plant host–defence responses, protecting hyphae from plant chitinases, but little is known on these effectors from nonpathogenic fungal endophytes. We found four putative LysM effectors in the genome of the endophytic nematophagous fungus Pochonia chlamydosporia (Pc123). All four genes encoding putative LysM effectors are expressed constitutively by the fungus. Additionally, the gene encoding Lys1—the smallest one—is the most expressed in banana roots colonised by the fungus. Pc123 Lys1, 2 and 4 display high homology with those of other strains of the fungus and phylogenetically close entomopathogenic fungi. However, Pc123 Lys3 displays low homology with other fungi, but some similarities are found in saprophytes. This suggests evolutionary divergence in Pc123 LysM effectors. Additionally, molecular docking shows that the NAcGl binding sites of Pc123 Lys 2, 3 and 4 are adjacent to an alpha helix. Putative LysM effectors from fungal endophytes, such as Pc123, differ from those of plant pathogenic fungi. LysM motifs from endophytic fungi show clear conservation of cysteines in Positions 13, 51 and 63, unlike those of plant pathogens. LysM effectors could therefore be associated with the lifestyle of a fungus and give us a clue of how organisms could behave in different environments.This research was funded by European Project H2020 MUSA, Grant Number 727624
Eficacia del rimadyl® en el control del dolor y la recuperación postquirúrgica después de una cirugía por dislocación abomasal
Se han estudiado los efectos de la aplicación de Rimadyl® (carprofeno 50 mg/ml) sobre la concentración de cortisol, temperatura rectal, frecuencia respiratoria, frecuencia cardiaca y motilidad ruminal, con el objetivo evaluar su eficacia en el control del dolor y la recuperación postquirúrgica, al aplicarlo antes de la cirugía por dislocación abomasal. Se seleccionaron 24 vacas de características similares que iban a someterse a cirugía por dislocación abomasal y se asignaron al azar a uno de los dos tratamientos experimentales: Rimadyl® o suero salino fisiológico. La aplicación de Rimadyl® disminuye (P=0,006) la concentración plasmática de cortisol (11,3 ng/mL vs 22,13 ng/mL). Con el tiempo se reducen (P=0,024) los niveles de cortisol plasmático. Esta reducción es más acusada (P=0,0003) con Rimadyl® a las 6 horas de su aplicación. La producción de leche postcirugía fue mayor en los animales que recibieron Rimadyl® en comparación con los que se les aplicó suero salino fisiológic
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