493 research outputs found
Knowledge creation through cooperative experimentation
No full textSi tratta dello sviluppo della conoscenza attraverso approcci di sperimentazione. Il focus è sul processo di generazione di nuova conoscenz
Preliminary pages
No full textpp. i-v, 1-6Title page, IAMSLIC Conference Series, Table of Contents, Group photo, Introduction, Dedication to Merrill Everett Manke, Dedication to Lois F. Winemiller
Detection of shorter-than-skin-depth acoustic pulses in a metal film via transient reflectivity
No full textShort acoustic pulses are generated in SrRuO[subscript 3] transducers and detected at the surface of gold films by transient reflectivity. Contrary to expectations, acoustic pulses that are shorter than the optical skin depth of gold are resolved. A comparison of gold detection films that were grown under different deposition conditions demonstrates that the microstructure of a detection film can impact the shape of the detected signal.United States. Dept. of Energy (Grant DE-FG0200ER15087)National Science Foundation (U.S.) (Graduate Research Fellowship
Implementation of a dipole constant directivity circular-arc array
No full textWe briefly present the theory for a broadband constant-beamwidth transducer (CBT) formed by a conformal circular-arc array of dipole elements previously developed in seminal works. This technical report considers a dipole CBT prototype with cosine amplitude shading of the source distribution. We show that this leads to a readily-ecjualizable response from about 1 OOHz to 1 OkHz with a far-field radiation pattern that remains constant above the cutoff frequency determined by the beam-width and arc radius of the array, and below the critical frequency determined by discrete element spacing at which spatial aliasing effects occur. Furthermore, we show that the shape of the radiation pattern is the same as the shading ftinction, and remains constant over a broad band of frequencies.Not peer reviewe
Constant directivity circular-arc arrays of dipole elements
No full textWe develop the theory for a broadband constant-beamwidth transducer (CBT) formed by a conformal circular-arc line array of dipole elements. Appropriate amplitude shading of the source distribution leads to a far-field radiation pattern that is constant above a cutoff frequency determined by the prescribed beam width and arc radius. We illustrate the theory with examples, including numerical simulations of magnitude responses, full-sphere radiation patterns and directivity index. Unlike a circular-arc array of monopole elements, a dipole CBT maintains directivity control at low frequency. We give an example of one such array that achieves just 1 dB variation in directivity index over all frequencies.Not peer reviewe
Uma metodologia de calculo para a simulação de mancais radiais submetidos a carregamento dinamico
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro TecnologicoA teoria da lubrificação hidrodinâmica, baseada na equação de reynolds, é utilizada na determinação das características operacionais de mancais radiais submetidos a carregamentos dinâmicos. A equação de reynolds, na sua forma bidimensional, é integrada numericamente através dos volumes finitos. A cavitação do filme de óleo é considerada, o que torna o modelo matemático um problema de fronteira livre, contornado pelo uso de malhas não-ortogonais adaptadas a fronteira. O comportamento dinâmico do mancal representado pela trajetória do eixo, é obtido através da resolução de um sistema de equações diferenciais, originárias do balanço de forças entre o carregamento e a força hidrodinâmica gerada no mancal a cada instante de tempo. A interação do problema hidrodinâmico do filme de óleo e o problema de dinâmica do eixo é responsável pela geração de um campo de pressões continuamente variável com o tempo. A partir do conhecimento deste campo de pressões, as características operacionais, tais como vazão de óleo e perdas, podem ser determinadas, permitindo a otimização dos mancais em análise. Os resultados obtidos neste trabalho são comparados com resultados numéricos e experimentais existentes na literatura, alcançando-se boa concordância entre os mesmos
[Photograph 2012.201.B1257.0058]
No full textPhotograph used for a newspaper owned by the Oklahoma Publishing Company. Caption: "Dr. James V. Parcher (left) , head of the OSU school of civil engineering, looks on as Dr. Phillip G. Manke receives the national Defense Executive Reserve Plaque from E. A. Sparks (right) , division engineer, Bureau of Public Roads, Oklahoma City.
Constant Directivity Circular-Arc Arrays of Dipole Elements
No full textWe devdop the theory for a broadband constant-beamwidth transducer (CBT) formed by a conformal circular-arc line array of dipole elements. Appropriate amplitude shading of the source distribution leads to a far-field radiation pattern that is constant above a cutoff frequency determined by the prescribed beam width and arc radius. We illustrate the theory with examples, including numerical simulations of magnitude responses, full-sphere radiation patterns and directivity index. Unlike a circular-arc array of monopole elements, a dipole CBT maintains directivity control at low
frequency. We give an example of one such array that achieves just 1 dB variation in directivity index over all frequencies.Not peer reviewe
Implementation of a Dipole Constant Directivity Circular-Arc Array
No full textWe briefly present the theory for a broadband constant-beamwidth transducer (CBT) formed by a conformal
circular-arc array of dipole elements previously developed in seminal works. This technical report considers a
dipole CBT prototype with cosine amplitude shading of the source distribution. We show that this leads to a
readily-ecjualizable response from about 1 OOHz to 1 OkHz with a far-field radiation pattern that remains constant
above the cutoff frequency determined by the beam-width and arc radius of the array, and below the critical
frequency determined by discrete element spacing at which spatial aliasing effects occur. Furthermore, we show
that the shape of the radiation pattern is the same as the shading ftinction, and remains constant over a broad band
of frequencies.Not peer reviewe
Histokemijska analiza kutikule rakov z barvilom alizarin rdeče S: uporaba v proučevanju ličink raka enakonožca vrste Porcellio scaber
No full textExoskeletal cuticle of crustaceans is a chitinous matrix, produced apically by epidermis and stiffened by sclerotization and calcification. Embryos of terrestrial isopod crustacean Porcellio scaber develop within the female brood pouch, marsupium, and after hatching larvae mancae continue their development in the marsupium for another week. This study was performed to reveal at the histochemical level whether the exoskeletal cuticle of marsupial mancae is already calcified. Fifteen different procedures of histochemical staining with alizarin red S (ARS), established for calcified tissue localization primarily in vertebrate histology, were evaluated on mancae and adult P. scaber specimens. The best differential staining of the the exoskeletal cuticle was obtained by neutral buffered formaldehyde fixation, followed by paraffin sections staining with ARS 1 (pH 9) or ARS 2 (pH 6.4) or ARS 3 (pH 4.8)solution. Clear differential staining was achieved also in cryosections of formaldehyde fixed samples, stained with ARS 1 solution (pH 9). Our results suggests that prominent calcification of exoskeletal cuticle is present during postembryonic development of P. scaber mancae in the marsupium. Exoskeleton hardening is likely important also for body movements, that we observed in mancae before they are released from marsupium. The proposed procedures of ARS method are presumed to be applicable for histochemical studies of other calcified chitinous matrices.Eksoskeletna kutikula rakov je hitinski matriks na apikalni strani epidermisa. Trdnost kutikule je posledica sklerotizacije in kalcifikacije organskega matriksa. Embriji kopenskega raka enakonožca Porcellio scaber se razvijajo v vrečastem valilniku samice, marzupiju, kjer po izleganju nadaljujejo svoj razvoj približno en teden tudi ličinke manke. S histokemijsko metodo smo ugotavljali, ali je eksoskeletna kutikula marzupijskih mank že kalcificirana. Na vzorcih mank in odraslih rakov P. scaber smo ovrednotili petnajst različnih postopkov histokemijske analize z barvilom alizarin rdeče S (ARS), ki se uporabljajo za lokalizacijo kalcificiranega tkiva v histologiji vretenčarjev. Eksoskeletna kutikula se je izrazito diferencialno obarvala v primeru fiksacije z nevtralno raztopino formaldehida, ki ji je sledilo barvanje parafinskih rezin z eno izmed raztopin ARS: ARS 1 (pH 9), ARS 2 (pH 6.4) ali ARS 3 (pH 4.8). Jasno lokalizacijo smo dosegli tudi z barvanjem zamrznjenih rezin vzorcev, fiksiranih v formaldehidu in barvanih z raztopino ARS 1 (pH 9). Rezultati kažejo na znatno kalcifikacijo eksoskeletne kutikule že v postembrionalnem razvoju mank P. scaber v marzupiju. Trdnost eksoskeleta je najverjetneje pomembna tudi za gibanje mank, ki smo ga opazili pred sprostitvijo iz valilnika. Pričakujemo, da bodopostopki, ki jih predlagamo, uporabni tudi za histokemijska proučevanja kalcifikacije drugih hitinskih matriksov
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