23,419 research outputs found
Fully Turbulent Mean Velocity Profile for Purely Viscous non-Newtonian Fluids
No full textThe characteristic near wall behavior of turbulent flow of purely-viscous non-Newtonian fluids is discussed for both power-law (P.-L.) and Herschel-Bulkley (H.-B.) rheological models. A proper scaling is presented for H.-B. fluids to establish an analogy with power-law fluids with same flow index. To provide reference data for turbulent flow of non-Newtonian fluids, DNS simulations of power-law fluids are conducted in a rectangular channel for a large range of power-law indices ( = 0.5, 0.69, 0.75, 0.9, 1, 1.2). The DNS data show that the mean velocity profile in the viscous and logarithmic layers follow expressions of the form and respectively, where shows a logarithmic dependency on the flow index.Comparison with some experimental data shows the above formulation to be valid for Reynolds numbers (based on shear velocity) as high as 1000
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
Análisis bibliométrico de la actividad científica de los investigadores del CSIC en tres áreas, Biología y Biomedicina, Ciencia de los Materiales y Recursos Naturales : una aproximación metodológica a nivel micro (Web of Science, 1994-2004)
Get PDFRelations between x-ray timing features and spectral parameters of galactic black hole x-ray binaries
Get PDFWe present a study of correlations between spectral and timing parameters for a sample of black hole X-ray binary candidates. Data are taken from GX
339-4, H 1743-322, and XTE J1650-500, as the Rossi X-ray Timing Explorer
(RXTE) observed complete outbursts of these sources. In our study we investigate outbursts that happened before the end of 2009 to make use of the high-energy coverage of the HEXTE detector and select observations that
show a certain type of quasi-periodic oscillations (type-C QPOs). The spectral parameters are derived using the empirical convolution model simpl to model the Comptonized component of the emission together with a disc blackbody for the emission of the accretion disc. Additional spectral features, namely a reflection component, a high-energy cut-off, and excess emission at 6.4 keV, are taken into account. Our investigations confirm the known positive
correlation between photon index and centroid frequency of the QPOs and reveal an anti-correlation between the fraction of up-scattered photons and the QPO frequency. We show that both correlations behave as expected in the “sombrero”
geometry. Furthermore, we find that during outburst decay the correlation between photon index and QPO frequency follow a general track, independent of individual outbursts
Los indios tarahumaras de Chihuahua, México.. Anales del Museo Nacional de Arqueología, Historia y Etnografía. Num. 27 Tomo II (1935) Quinta Época (1934-1938)
No full textBancroft, H. N. - Vols. 1-5, 15-16.Bartlett's Personal Narratives. - Vols. 1 y 2.Basauri, Carlos. - Monografía de los Tarahumaras.Holmes, Ensayos Antropológicos de.Hughes, Doniphan's Expedition.Keane, The World's Peoples.Lumholtz, Carl, Unknown Mexico.Publicaciones de la Universidad de California sobre Arqueología y Etnología Americana. - Vol. 17.Spense, Mexico of the Mexicans.Spinden, H. J. - Ancient Civilizations of Mexico and Central America.Starr, Frederic. - In Indian Mexico.Thomas, W. I. - Sourcebook for Social Origins.University of California Publications In History. - Vol. l
Educational Probe for Developing Online Education: A Case of Online Problem-Based Learning in Design Education in India
Get PDFThe COVID-19 pandemic brought challenges and opportunities for higher education and one of the important areas was online education. Especially in design field, Online Problem-Based Learning has emerged as a promising method. This paper explores the potential of online-PBL and how it can be developed through a prototype approach. An action research in Indian HEI shows insights regarding the potentiality of online-PBL and application of a prototype approach to educational development activities. A concept of educational probes was proposed as a method to design educational program. © The Author(s), 2022
Turbulence statistics of turbulent boundary layer flow following injection of drag-reducing surfactant solution
No full textTo investigate streamwise variations of turbulence statistics in the wide range of the drag reduction ratio for the zero-pressure-gradient turbulent boundary layer flow due to the injection of drag-reducing nonionic surfactant solutions, we performed the laser-Doppler velocimetry (LDV) measurement at a new experimental apparatus with the larger size than previous one. The drag reduction ratio up to 76% could be obtained, at which the mean velocity in wall-units was beyond the Virk's ultimate for polymer solutions
A molecular dynamics study of N-A-S-H gel with various Si/Al ratios
No full textThe understanding of sodium aluminosilicate hydrate (N-A-S-H) gel is still limited due to its complex and amorphous structure. Recently, molecular dynamics simulation has provided a unique opportunity to better understand the structure of N-A-S-H gel from nanoscale. In this work, the N-A-S-H gel structure was obtained by simulating the polymerization of Si and Al monomers by molecular dynamics. The simulated polymerization process is in good agreement with the experimental results especially in terms of the reaction rate of Si and Al species. The atomic structural features of the N-A-S-H gel were analyzed in terms of bond length and bond angle information, simulated X-ray diffraction (XRD) and Qn distribution. A significant finding is the existence of pentacoordinate Al in all simulated N-A-S-H structures, indicating that pentacoordinate Al in geopolymer does not only come from raw material. Besides, the results show that a smaller Si/Al ratio led to a more crosslinked and compacted structure of N-A-S-H gel
Historia de la muerte y glorioso martyrio del sancto Innocente, que llaman de la Guardia, natural de la ciudad de Toledo ... : con otros tractados de mucha doctrina y preouecho, que son los de la plana siguiente
Get PDFEl pie de imp. consta en colofón, en v. de h. 78 y de h. 96 de la primera secuencia de fol.Colofón en v. de h. 43 y de h. 88 de la segunda secuencia de fol.Sign.: ¶\p10\s, A-M\p8\s, ¶\p4\s ; A-L\p8\s, O\p3\s.Ports. con grab xil.Ilustraciones xil.Contiene: Tractado y platica de la ciudad de Toledo a sus vezinos afligidos .../author el maestro Alexio Venegas de Busto ; corregido por ... Rodrigo de Yepes ..., de h. 79 a 96 de la primera secuencia de fol. ; Tractado y descripcion breue y c¯opendiosa de la tierra sancta de Palestina ..., h. 1-43 de de la segunda secuencia de fol., con port. propia ; Tractado de la peregrinacion que Iesu Christo ... hizo en este mundo, h. 44-88 de la segunda secuencia de fol
A comparative study of the Finnish 4-H organization and the Wisconsin 4-H organization
Get PDFPlan BThe education of today’s youth, tomorrow’s future, is the focus of the 4-H organization. The aim of the 4-H program is to develop life skills in youth using hands-on learning. 4-H began in the heartland of America in the early 1900’s and soon stretched around the globe. 4-H or a partner organization of 4-H can be found in over 63 countries in the world (V. Gobeli, personal communication, February 25, 2002). The programming, structure, and principles of 4-H programs around the world are all based on the program that began in the United States, but the methods used are different in every country. It is even different among states in the United States. Each program has unique ideas used in the education of youth, but little communication exists to share these ideas among countries. The purpose of this study is to compare another country’s 4-H program to the program that has been long established in Wisconsin. The goal of the study is to show the similarities and difference of two programs that have been created using the same theme, “learning by doing.” Due to the scope of this research, the researcher chose to look only at one country. The country of Finland was chosen for comparison because of its location, similar structure, and its well-established example of European youth programming. The researcher looked at the history of the two programs to help establish the similarities and difference that might exist. The Finnish 4-H Federation began after two men visited the United States and observed the success of club work administered by the United States Department of Agriculture. The program ideas were changed to fit the needs of the Finnish people, with the key concept of life skill development remaining the same. The researcher also found that many articles have been written to show an importance in international programming and international travel. The research was done using ethnographic research along with a qualitative written survey and various interviews. The written survey was used to gain basic information before ethnographic research began. The research revealed that although the programs have the same basic goal, the two programs are very different. The largest differences were seen in projects offered, staff roles, leaders participation, and competition. It was found that both 4-H programs contained ideas of superior quality. If these ideas were shared, it could help to improve the program in the other country. The research not only compared the two programs, but also recommended further programs or studies that could be established based on the research performed
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