139,835 research outputs found
In-situ stress at the northern portion of the Chelungpu fault, Taiwan, estimated on boring cores recovered from a 2-km-deep hole of TCDP
No full textProcessing and fluid flow characteristics of hot isostatically pressed porous alumina for aerostatic bearing applications
Full text linkDespite their well known superior load and stiffness characteristics, the wide-spread
use of porous aerostatic bearings in preference to other bearing types has been
hampered by difficulties in controlling the permeability of the porous material during
manufacture and machining, in addition to instability problems caused by the additional
volume of air trapped amongst the pores. Recent development in porous aerostatic
bearings centres around the use of a thin dense surface layer to overcome the stability
problem.
The production of single and two-layered porous ceramic structures for aerostatic
bearing applications have been investigated using the free-capsule hot isostatic pressing
process, and in conjunction with slip and tape castings. The influence of various
process parameters on open porosity, and the empirical relationships between porosity,
particle size and the resulting fluid flow and structural properties were determined from
experimental data. The measurement accuracy and uniformity of temperature within
the furnace are identified as the most important factors affecting consistency and
predictability of the permeability of the porous substrate.
Prototype bearings were produced and tested, based on the above materials. The
single-layer bearing was, not unexpectedly, found to be unstable over a wide operating
range. The use of a two-layeredb earingm ateriale liminatedth e stabilityp roblem.
Initial measurements of the slip coefficient of the porous material in air and at small
gaps indicated significant deviation from the Beavers' theory. The effect of velocity
slip was found to be significant in both test bearings, and was allowed for by the
addition of an equivalent clearance to the bearing gap. The value of the equivalent
clearance was deduced from experimental data. The static load characteristics and the
pressure profile of both test bearings agreed well with published theories, once the
above-mentioned correction for slip was applied
Spatially-localized time dependent solutions including turbulence and their interactions in 2D Kolmogorov flow
No full textIn 2D Kolmogorov flow in small aspect ratio domains, spatially-localized solutions such as kink, traveling or time-dependent kink-antikink pars coexist. However, the conservation of the flow rate in the y direction strongly restrict combination of localized solutions and their positioning. We find that by adding a homogeneous flow U y their positioning is controlled and each of localized solutions including a spatially-localized chaos is isolated. Numerical results suggest that these isolated solutions can be elements constructing a whole flow
Characteristics of overlap region in high-Reynolds number turbulent channel flow
No full textDirect numerical simulation of the fully developed turbulent channel flows have been carried out at the Reynolds number based on the friction velocity and the channel half width, 2000, 4000 and 8000. A hybrid 10th order accurate finite difference scheme in the stream and spanwise directions, and a second-order scheme in the wall-normal direction is adapted as the spatial discretization method. We observed the plateau profiles in the indicator function corresponded to the von Karman constant. Furthermore, second peak of streamwise pre-multiplied spectra were appeared in the same wall normal height, 300 < y+ < 600, in case of Re = 4000. Nevertheless, the effects of the lager than the channel half height scale on the streamwise turbulent intensity are fixed contributions without dependence on Reynolds number. These results suggested that the new streamwise vortexes are formed between buffer layer and outer layer with increasing of Reynolds number
MOMENT OF FORCE AND MECHANICAL POWER IN GIANT SWING ON THE HORIZONTAL BAR
Full text linkIntroduction
In the giant swing backwards, frictional force acts upon the grip and air resistance acts upon the whole body (Hay, 1978; and Kreighbaum and Barthels, 1981). These resistive forces affect the rotation of the body and cause a loss of mechanical energy. Therefore in order to complete the rotation, the gymnast has to offset these energy losses using muscular work (Hay, 1978). It has been reported that changes in mechanical energy occur during the backward giant swing. The total energy of the body is decreased during the second half of the downswing and almost recovered in the first half of the upswing. These results suggest that muscular work is done in the first half of the upswing to offset the loss of mechanical energy in the last half of the downswing (Okamoto, Sakurai, Ikegami and Yabe)
Electron microscopic, immunofluorescent and virological studies on a rhabdomyosarcoma in epidermodysplasia verruciformis
No full textA subcutaneous tumor of a patient with epidermodysplasia verruciformis
was studied by the light microscopy, the electronmicroscopy and
the immunofluorescent test. The tumor cells were histologically pleomorphic
and electronmicroscopically contained varying amounts of cytoplasmic filaments without Z-band formation. The antimyosin serum stained the tumor cells, showing their myogenic origin. No virus or virus-like particles were observed in the tumor. Tumor antigens stainable by the
patient's serum were not detected. Hamsters inoculated with the tumor extract at birth developed no noticeable diseases.</p
Comparación de dos índices de reabsorción de agua en tres poblaciones de Capromys Pilorides (Rodentia : Capromyidae)
Full text linkThe objective of this work was to analyze three populations of hutia conga (Capromys pilorides) comparatively in different habitat (swamp and forest) by means of two indexes of retention of water (reabsorption index) using the index proposed by YABE (1983) and a index proposed by the first authors, where is related the renal thickness of marrow to head trunk length (HTL) in order to eliminate the effect of HTL, in two trimester of the year. The three populations were analyzed from february, marz to april (FMA) and August, september and october (ASO). All the animal captured were adult. The measures used was head trunk length (HTL) and renal thickness of marrow (RTM) and cortex (RTC) in mm, measured with tape measure (HTL) and caliper (RTN and RTC). The index proposed by YABE (1983), which measures the renal thickness of marrow in relation to thickness of the kidney, and the renal index relative to long proposed by the first authors (IRRl), where compared. The index IRRL contributed to differentiate the population of mangrove habitat of forest habitat with high discrimination values and consistent, independent of the season effects, this result was not evidenced in the index of YABE (1983) neither in the absolute value of renal thickness of marrow.El objetivo de este trabajo fue analizar comparativamente tres poblaciones de jutía conga (Capromys pilorides) en diferentes hábitat (manglar y bosque) mediante dos índices de retención de agua (índice de reabsorción) utilizando el índice propuesto por YABE (1983) y un índice propuesto por los autores, donde se relaciona el grosor de la médula con una medida lineal que elimine el posible efecto del tamaño (LCT), en dos trimestres del año. Las tres poblaciones se analizaron para los trimestre febrero, marzo y abril (FMA) y agosto, septiembre y octubre (ASO). Todos los ejemplares capturados fueron adultos. Las variables utilizadas largo cabeza tronco (LCT), grosor de la médula (GM) y corteza renal (GC) fueron expresadas en milímetro (mm) y medidas con una cinta métrica para el LCT y un pie de rey para las variables GM y GC. Se compararon el índice renal propuesto por YABE (IRRY), el cual mide el grosor de la médula renal relativa al grosor del riñón y el índice propuesto por el primer autor, que mide el grosor de la médula renal relativo al largo cabeza tronco (IRRL). El índice renal relativo al largo (IRRL) contribuyó a diferenciar las poblaciones de hábitat manglar de las poblaciones de hábitat bosque con un alto valor discriminativo y consistente, independiente del efecto estacional, resultados que no se evidenció en el índice de YABE (1983) ni en el grosor de la médula renal como variable absoluta
La 'circunstancia' de 'Herederos y Pretendientes
Full text linkIn June 2010, the Ortega y Gasset Foundation hosted a Conference about the “Spanish Philosophical Transition” in order to debate the book of Francisco Vázquez, La filosofía española. Herederos y Pretendientes. Una lectura sociológica (1963-1990), recently published. This paper is the author’s response to criticism raised in the Conference and to published reviews received by this book. First, the author summarized the argument of Herederos y pretendientes. Secondly he responds and takes into account the most important objections against the book’s hypothesis and methodology. Finally the author evaluates the favorable judgments received by the book and suggests the limits of the historian’s task.Fundación Ortega y Gasset-Marañó
Comparación de dos índices de reabsorción de agua en tres poblaciones de Capromys Pilorides (Rodentia: Capromyidae)
No full textEl objetivo de este trabajo fue analizar comparativamente tres poblaciones dejutía conga (Capromys pilorides) en diferentes hábitat (manglar y bosque)mediante dos índices de retención de agua (índice de reabsorción) utilizando elíndice propuesto por YABE (1983) y un índice propuesto por los autores, dondese relaciona el grosor de la médula con una medida lineal que elimine elposible efecto del tamaño (LCT), en dos trimestres del año. Las trespoblaciones se analizaron para los trimestre febrero, marzo y abril (FMA) yagosto, septiembre y octubre (ASO). Todos los ejemplares capturados fueronadultos. Las variables utilizadas largo cabeza tronco (LCT), grosor de la médula(GM) y corteza renal (GC) fueron expresadas en milímetro (mm) y medidas conuna cinta métrica para el LCT y un pie de rey para las variables GM y GC. Secompararon el índice renal propuesto por YABE (IRRY), el cual mide el grosorde la médula renal relativa al grosor del riñón y el índice propuesto por el primerautor, que mide el grosor de la médula renal relativo al largo cabeza tronco(IRRL). El índice renal relativo al largo (IRRL) contribuyó a diferenciar laspoblaciones de hábitat manglar de las poblaciones de hábitat bosque con unalto valor discriminativo y consistente, independiente del efecto estacional,resultados que no se evidenció en el índice de YABE (1983) ni en el grosor dela médula renal como variable absoluta.</jats:p
Author self-citation in orthodontics is associated with author origin and gender.
Full text linkBACKGROUND
The aims of this bibliometric study were to determine author self-citation trends in high-impact orthodontic literature and to investigate possible association between self-citation and publication characteristics.
METHODS
Six orthodontic journals with the highest impact factor as ranked by 2017 Journal Citation Reports were screened for a full publication year (2018) for original research articles, reviews, and case reports. Eligible articles were scrutinized for article and author characteristics and citation metrics. Univariable and multivariable negative binomial regression was used to examine associations between self-citation incidence and publication characteristics.
RESULTS
Medians for author self-citation rate of the most self-citing authors and self-citations were 3.03% (range 0-50) and 1 (range 0-19), respectively. In the univariable analysis, there was no association between self-citation counts and study type (P = 0.41), article topic (P = 0.61), number of authors (P = 0.62), and rank of authors (P = 0.56). Author origin (P = 0.001), gender (P = 0.001) and journal (P = 0.05) were associated with self-citation counts and in the multivariable analysis only origin and gender remained strong self-citation predictors. Asian authors and females self-cited significantly less often than all other regions and male authors.
CONCLUSIONS
Authors in orthodontics do not self-cite at a frequency that suggests potential citation manipulation. Author origin and gender were the only variables associated with citations counts. More bibliometric research is necessary to draw solid conclusions about author self-citation trends in orthodontic literature
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