An Experimental and Numerical Study of Ballistic Impacts on a Turbine Casing Material at Varying Temperatures

An experimental and numerical study of ballistic impacts on steel plates at various temperatures (700ºC, 400ºC and room temperature) has been carried out. The motivation for this work is the blade‐off event that may occur inside a jet engine turbine. However, as a first attempt to understand this complex loading process, a somewhat simpler approach is carried out in the present work. The material used in this study is the FV535 martensitic stainless steel, which is one of the most commonly used materials for turbine casings. Based on material test data, a Modified Johnson‐Cook (MJC) model was calibrated for numerical simulations using the LS‐DYNA explicit finite element code (see Figure 1). To check the mesh size sensitivity, 2D axisymmetric finite element models with three different mesh sizes and configurations were used for the various temperatures. Two fixed meshes with 64 and 128 elements over the 2mm thick plate and one mesh with 32 elements over the thickness with adaptive remeshing were used in the simulations. The formation of adiabatic shear bands in the perforation process has been found critical in order to achieve good results. Adiabatic shear bands are formed by the temperature rise due to the accumulation of plastic strain during impact (see Figure 2). The influence of the thermal softening in the plastic model has hence been analyzed for the room temperature impact tests, where the temperature gradient is highest

A data-globe and immersive virtual reality environment for upper limb rehabilitation after spinal cord injury

While a number of virtual data-gloves have been used in stroke, there is little evidence about their use in spinal cord injury (SCI). A pilot clinical experience with nine SCI subjects was performed comparing two groups: one carried out a virtual rehabilitation training based on the use of a data glove, CyberTouch combined with traditional rehabilitation, during 30 minutes a day twice a week along two weeks; while the other made only conventional rehabilitation. Furthermore, two functional indexes were developed in order to assess the patient’s performance of the sessions: normalized trajectory lengths and repeatability. While differences between groups were not statistically significant, the data-glove group seemed to obtain better results in the muscle balance and functional parameters, and in the dexterity, coordination and fine grip tests. Related to the indexes that we implemented, normalized trajectory lengths and repeatability, every patient showed an improvement in at least one of the indexes, either along Y-axis trajectory or Z-axis trajectory. This study might be a step in investigating new ways of treatments and objective measures in order to obtain more accurate data about the patient’s evolution, allowing the clinicians to develop rehabilitation treatments, adapted to the abilities and needs of the patients.

Biomimetismo entre los endemismos arquitectónicos y taxones en Cantabria

Es notoria la importancia de la naturaleza en la evolución de la arquitectura. Hasta la gran eclosión de la industria manufacturera y la mejora en las infraestructuras de comunicación, se podría decir que ambas corrían paralelas, para a partir de ahí dejar “congelada” la sabiduría popular y dar un salto a la globalidad, generando una situación de libertad arquitectónica prácticamente total, que independiza la construcción de su ubicación. "El biomimetismo es esencialmente un campo de investigación interdisciplinar, una serie de colaboraciones entre botánicos, físicos, matemáticos, ingenieros y zoólogos; donde la rígida división entre disciplinas «puras» cede lugar a un área de investigación que apunta a generar tecnología inteligente (smarttechnologies), utilizando materiales o procesos que sean de alguna manera sensibles al medio ambiente." (M. Weinstock, 1998). “La morfología de las plantas en los diferentes climas parece tener cierta analogía con la edificación, ya que algunas de las tensiones que inciden en su forma (tales como las variaciones de temperatura) corresponden de manera similar a las necesidades humanas.” (V. Olgyay 1963). En el presente trabajo se han estudiado las especies endémicas que nos rodean, para poder leer a través de ellas millones de años de supervivencia en este entorno, con el fin de mimetizar sus respuestas. También se han estudiado diferentes tipologías de arquitectura vernácula y su simulación energética, con el propósito de evaluar la demanda energética optima exigible. A partir de una ubicación específica, la orientación, compacidad, perforación y las características de la envolvente son los elementos que más influyen en la demanda energética de una edificación. Tanto la forma como los materiales pueden ser mimetizados con la naturaleza. En esta Tesis se han cuantificado los parámetros de diseño formales tomando como referencia las especies vegetales o la arquitectura vernácula, sin perder de vista los objetivos buscados por normativas o institutos en la reducción del consumo energético vinculado a la calefacción y ventilación. ABSTRACT The importance of the nature in the evolution of the architecture is well-known. Until the great burst of the manufacturing industry and the improvement in communication infrastructures, it would be possible to be said that both ran parallel, stops there from leaving “frozen” the popular wisdom and jump to the globalization, creating a situation almost complete architectural freedom, that it frees the construction of its location. "Biomimicry is essentially an interdisciplinary field of research, a series of collaborations among botanists, physicists, mathematicians, engineers and zoologists; where the rigid division between "pure" disciplines gives way to an area of research that aims to generate intelligent technology (smarttechnologies), using materials and processes that are in some environmentally sensitive manner. "(M. Weinstock, 1998). “The morphology of the plants in different climates seems to have some analogy with the building, as some of the tensions that affect their form (such as the temperature variations) are similar to the human necessities.” (V. Olgyay 1963). In the present work, the endemic species that surround to us have been studied, to be able to read through them millions of years of survival in this environment, in order to mimic their answers. Also different types or popular architecture and their energy simulation have been studied, in order to evaluate the rate of energy optimum demand. Orientation, compactness, perforation and characteristics of the envelope are the elements that influence more in the energy demand of a building. The shape and materials can be mimic with nature. Each of them has been quantified in this work by reference plant species or popular architecture, without losing sight of the objectives sought by regulations or institutes about reduction in energy consumption.

Physically-sound simulation of low-velocity impact on fiber reinforced laminates

A high-fidelity virtual tool for the numerical simulation of low-velocity impact damage in unidirectional composite laminates is proposed. A continuum material model for the simulation of intraply damage phenomena is implemented in a numerical scheme as a user subroutine of the commercially available Abaqus finite element package. Delaminations are simulated using of cohesive surfaces. The use of structured meshes, aligned with fiber directions allows the physically-sound simulation of matrix cracks parallel to fiber directions, and their interaction with the development of delaminations. The implementation of element erosion criteria and the application of intraply and interlaminar friction allow for the simulation of fiber splits and their entanglement, which in turn results in permanent indentation in the impacted laminate. It is shown that this simulation strategy gives sound results for impact energies bellow and above the Barely Visible Impact Damage threshold, up to laminate perforation conditions

Características físicas e químicas das águas superficiais e subterrâneas (nas proximidades do canal), dos ribeirões do Moquém e Água Clara (Médio Tietê Superior - SP), em função das variações hidrológicas

As teorias sobre o funcionamento dos sistemas lóticos evoluíram nos últimos anos, os condicionantes geológicos/geomorfológicos como também as regiões de transição têm recebido importância crescente. As regiões de transição merecem destaque uma vez que os sistemas lóticos estabelecem interações de fluxo com os ambientes vizinhos (atmosféricos, terrestres e subterrâneos) e a troca de materiais estabelecida entre esses sistemas é importante para a definição de suas características. As bacias hidrográficas dos ribeirões do Moquém e Água Clara, estudadas no presente trabalho, apresentam: proximidade geográfica além de semelhanças morfológicas e climáticas, porém diferem quanto aos aspectos geológicos e geomorfológicos. A partir desses aspectos, a presente pesquisa investigou as flutuações sazonais nas relações físicas, química e hidrológicas entre águas superficiais e subterrâneas (adjacências do canal), na região do baixo curso dos ribeirões já citados. Foram escolhidos dois trechos em cada ribeirão para a realização de: (1) inventário hidrológico mensal, a partir de medidas de velocidade de escoamento, vazão e do nível de água em poços instalados na região marginal dos rios nos trechos de estudo; (2) caracterização física e química de testemunhos da região marginal dos rios, onde foram utilizadas amostras obtidas durante a perfuração dos poços; (3) amostragens das águas superficiais subterrâneas no mesmo período do inventário para a determinação das características físicas e químicas das mesmas. Os resultados destacaram os seguintes itens. O fluxo de base garantiu vazões regulares e elevadas ao ribeirão Água Clara, ao mesmo tempo que as vazões foram quase insignificantes no ribeirão do Moquém, fato esse que apresenta importância ecológica. A química das águas dos ribeirões estudados é distinta, possivelmente, como resposta às características naturais das bacias. Nos dois trechos de estudo, as águas superficiais e subterrâneas apresentaram diferenças físicas e químicas, o que pode indicar que as trocas entre o canal do rio e suas adjacências são pequenas e/ou lentas. Com base nas observações desta pesquisa, recomenda-se que as características quantitativas e qualitativas, distintas, entre as águas dos ribeirões do Moquém e Água Clara devem ser avaliadas durante a tomada de decisões em processos de gestão de recursos hídricos.

I. Embroidered pocketbook, 1774

This series contains one rectangular, embroidered pocketbook with foldover flaps embroidered with wool thread in green, red, blue, purple, and cream colors. The interior is lined with pink silk and has cardboard inserts. "FISHER AMES 1774" is embroidered on one of the interior flaps of the wallet. This object was most likely made for Fisher Ames by a female member of his family or a friend, possibly to commemorate his graduation from Harvard in 1774. A child’s leather glove that was inserted in one of the pockets is also housed in HUM 96 Box 1.

Cellular slabs with and without insulation submitted to fire conditions

The wooden cellular slabs are lightweight structures, easy to assemble, and with excellent architectural features, as good thermal and acoustic conditions. The wooden cellular slabs with perforations are typical and very common engineering solutions, used in the ceiling or flooring to improve the acoustic absorption of compartments, and also have a good insulation and relevant architectonic characteristics. However, the high vulnerability of wooden elements submitted to fire conditions requires the evaluation of its structural behaviour with accuracy. The main objective of this work is to present a numerical model to assess the fire resistance of wooden cellular slabs with different perforations. Also the thermal behaviour of the wooden slabs will be compared considering material insulation inside the cavities. The time-temperature history and the residual cross-section of wooden slabs were numerically measured and analysed.

Wooden cellular slabs with and without insulation submitted to fire conditions

The wooden cellular slabs are lightweight structures, easy to assemble, and with excellent architectural features, as thermal and acoustic conditions. The wooden cellular slabs with perforations are typical and very common engineering solutions, used in the ceiling or flooring plates to improve the acoustic absorption of compartments, and also have a good insulation and relevant architectonic characteristics. However, the high vulnerability of wooden elements submitted to fire conditions requires the evaluation of its structural behavior with accurately. The main objective of this work is to present a numerical model to assess the fire resistance of wooden cellular slabs with different perforations. Also the thermal behavior of the wooden slabs will be compared considering material insulation inside the cavities

British manufactures.

[Vols. 4-6] are called "Series IV-VI."

An Economic report on the gloves and mittens industry in Puerto Rico /

Cover title.

Gun-shot wounds of the small intestines /

Printed wrappers.

Stories by American authors.

v. 6. The village convict, by C. H. White. The Denver express, by A. A. Hayes. The misfortunes of Bro' Thomas Wheatley, by Lina R. Fairfax. The heartbreak cameo, by L. W. Champney. Miss Eunice's glove, by A. Webster. Brother Sebastian's friendship, by H. Frederic.--v. 7. The bishop's vagabond, by Octave Thanet. Lost, by E. Bellamy. Kirby's coals of fire, by Louise Stockton. Passages from the journal of a social wreck, by Margaret Floyd. Stella Grayland, by J. T. McKay. The image of San Donato, by Virginia W. Johnson.--v. 8. The brigade commander, by J. W. De Forest. Split zephyr, by H. A. Beers. Zerviah Hope, by Elizabeth S. Phelps. The life-magnet, by A. A. Adee. Osgood's predicament, by Elizabeth D. B. Stoddard.--v. 9. Marse Chan, by T. N. Page. Mr. Bixby's Christmas visitor, by C. S. Gage. Eli, by C. H. White. Young Strong of "The Clarion," by Milicent W. Shinn. How old Wiggins wore ship, by Captain R. T. Coffin. "--mas has come," by L. Kip.--v. 10. Pancha, by T. A. Janvier. The ablest man in the world, by E. P. Mitchell. Young Moll's peevy, by C. A. Stephens. Manmat'ha, by C. De Kay. A daring fiction, by H. H. Boyesen. The story of two lives, by Julia Schayer.

Immigrants in industries. (In twenty-five parts).

--pt. 17-20 (v. 16) Copper mining and smelting. Iron ore mining. Anthracite coal mining. Oil refining.--pt. 21-22 (v. 17-18) Diversified industries; pt. 21, General tables; pt. 22, The floating immigrant labor supply.--pt. 23 (v. 19-20) Summary report on immigrants in manufacturing and mining.--pt. 24 (v. 21-22) Recent immigrants in agriculture.--pt. 25 (v.23-25) Japanese and other immigrant races in the Pacific coast and Rocky mountain states: v. 1, Japanese and East Indians; v. 2, Agriculture; v. 3, Diversified industries.

Microstructure and grain boundary microanalysis of X70 pipeline steel

Grain boundaries (GBs), particularly ferrite: ferrite GBs, of X70 pipeline steel were characterized using analytical electron microscopy (AEM) in order to understand its intergranular stress corrosion cracking (IGSCC) mechanism(s). The microstructure consisted of ferrite (alpha), carbides at ferrite GBs, some pearlite and some small precipitates inside the ferrite grains. The precipitates containing Ti, Nb, V and N were identified as complex carbo-nitrides and designated as (Ti, Nb, WC, N). The GB carbides occurred (1) as carbides along ferrite GBs, (2) at triple points, and (3) at triple points and extending along the three ferrite GBs. The GB carbides were Mn rich, were sometimes also Si rich, contained no micro-alloying elements (Ti, Nb, V) and also contained no N. It was not possible to measure the GB carbon concentration due to surface hydrocarbon contamination despite plasma cleaning and glove bag transfer from the plasma cleaner to the electron microscope. Furthermore, there may not be enough X-ray signal from the small amount of carbon at the GBs to enable measurement using AEM. However, the microstructure does indicate that carbon does segregate to alpha : alpha GBs during microstructure development. This is particularly significant in relation to the strong evidence in the literature linking the segregation of carbon at GBs to IGSCC. It was possible to measure all other elements of interest. There was no segregation at alpha : alpha GBs, in particular no S, P and N, and also no segregation of the micro-alloying elements, Ti, Nb and V. (C) 2003 Kluwer Academic Publishers.