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Literatura académica sobre el tema "Radio 3 (Spain)"

Autor: Grafiati

Publicado: 4 de junio de 2021

Última modificación: 14 de febrero de 2022

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Artículos de revistas sobre el tema "Radio 3 (Spain)"

Sovers, O. J., C. D. Edwards, C. S. Jacobs, G. E. Lanyi y R. N. Treuhaft. "The JPL 1986–3 Extragalactic Reference Frame". Symposium - International Astronomical Union 133 (1988): 461–64. http://dx.doi.org/10.1017/s0074180900140021.

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Intercontinental dual-frequency radio interferometric measurements were carried out during 1978 to 1985 between NASA's Deep Space Network stations in California, Spain, and Australia. Analysis of 6800 pairs of delay and delay rate observations made during 51 sessions produced a catalog of positions of 106 extragalactic radio sources, fairly uniformly distributed over the celestial sphere between −45° and +85° declination. Almost all of the resulting source positions have formal uncertainties between 0.5 and 3 milliarcseconds, with their distributions peaking somewhat below 1 mas. Root-mean-square uncertainties are 2.1 and 2.0 mas for RA and declination, respectively. Evidence is found for a long-term drift of the Earth's rotation axis in inertial space, relative to the 1984 IAU precession and nutation models. Tests for time variability of positions of 32 frequently observed sources place limits at the 1 mas/yr level. Comparisons with independently determined source catalogs of comparable quality show differences of positions of common sources that amount to a few mas, and may indicate the level of systematic errors in VLBI source position measurements.

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Blanco, Juan Carlos, Yolanda Cortés y Emilio Virgós. "Wolf response to two kinds of barriers in an agricultural habitat in Spain". Canadian Journal of Zoology 83, n.º 2 (1 de febrero de 2005): 312–23. http://dx.doi.org/10.1139/z05-016.

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We examined the effect of two kinds of barriers on an expanding gray wolf, Canis lupus L., 1758, population in an agricultural habitat in north-central Spain. The barriers were (i) a four-lane fenced highway along a flat area without wildlife-crossing facilities, and (ii) the River Duero Artery (RDA), comprising the river itself (50–100 m wide) and several small infrastructures along it. From March 1997 to October 2001, all 4 radio-collared wolves living <15 km from the highway (1 adult territorial male, 1 territorial breeder female, 1 dispersing male, and 1 female in 3 periods of her life (territorial immature, disperser, and territorial breeder) crossed it on between 4% and 33% of 45–163 monitoring days via vehicle bridges. Moreover, 4 more highways that we monitored in areas without radio-collared wolves have not delayed expansion of the increasing wolf population, suggesting that these highways are not an important barrier for wolves in our study area. In contrast, only 3 of 8 wolves radio-collared <5 km from the RDA were detected crossing it, and 2 of those 3 started to cross it only after severe habitat disturbance; in addition, the RDA seems to have delayed wolf expansion for some 15 years, which suggests that it is a semipermeable barrier for wolves. We discuss the likely consequences of the RDA on the recovery of the Iberian wolf population.

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Despois, D., T. Forveille, J. Schraml, D. Bockelée-Morvan, J. Crovisier y E. Gérard. "Observations of the HCN Molecule in Comet Halley". Symposium - International Astronomical Union 120 (1987): 429–30. http://dx.doi.org/10.1017/s0074180900154439.

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We report here the detection of the J 1-0 rotational line at 88.6 GHz of hydrogen cyanide in comet Halley. Six observational runs were made in the Nov. 19-Dec. 3 1985 period with the IRAM 30-m millimetre radio telescope at Pico Veleta (Spain), when the comet was at rh ~ 1.56 AU from the Sun and Δ ~ 0.63 AU from the Earth.

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Fajula, Anna, Mariluz Barbeito, Estrella Barrio, Ana Maria Enrique y Juan José Perona. "Feminist Stereotypes and Women’s Roles in Spanish Radio Ads". Media and Communication 9, n.º 2 (23 de marzo de 2021): 39–51. http://dx.doi.org/10.17645/mac.v9i2.3762.

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This article takes a quantitative approach to Spanish radio advertising and the stereotypes and female roles that it broadcasts in a medium that has traditionally had high female audience rates in our country. From content analysis of 679 radio ads extracted from the 3 main general Spanish radio stations and collected 10 years apart, the study attempts to show the evolution (or regression) of how radio advertising portrays women. The radio in Spain has always been a medium anchored in the real world that has also provided some degree of space to broadcast social movement. #MeToo, as a phenomenon promoting female empowerment, was no exception. Therefore, this longitudinal study aims to demonstrate whether the social movements that led to increased female activism have been reflected in a change of roles and stereotypes projected by radio advertising messages. The work presented here looks at the concept of role from a dual perspective: firstly, it focuses on the role played by female voices in radio advertising items. Secondly, it works on the concept of role by assimilating it into the female image projected in radio advertising items. The results obtained between the two samples are remarkably similar, demonstrating a clear tendency to polarise the female image and confirming that women are still being portrayed in significantly traditional roles.

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Vázquez, R., L. F. Miranda, J. M. Torrelles, C. Eiroa y J. A. López. "Radio continuum and long-slit optical spectroscopy of the Planetary Nebulae Cn 3-1 and M 3-27". Symposium - International Astronomical Union 180 (1997): 283. http://dx.doi.org/10.1017/s0074180900131006.

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Long-slit optical spectroscopy and VLA-B radio continuum (λ = 3.6 cm) observations toward the compact planetary nebulae Cn 3-1 and M 3-27 are presented. Optical spectra were taken at different position angles (PAs) with the 2.2 m telescope at Calar Alto (Spain), covering the range from 6549 to 6751 Å. The radio and optical data show that the ionized shell of Cn 3-1 is an ellipsoid (size ≃ 6″ × 5″, PA ≃ 72°) containing a bright ring-like equatorial zone (size ≃ 2″.6, expansion velocity ≃ 14 km s–1) and two bright point-symmetric arcs, extending from the equator towards the polar regions of the ellipsoid (Fig. 1). These arcs seem to be filamentary structures embedded in the ellipsoid. An ionized stellar wind has been detected through faint extended wings in the Hα (≃ 660 km s–1) and [N II] (≃ 460 km s–1) emission lines. M 3-27 is unresolved at 3.6 cm (size ≤ 0″6). The detected [N II] and [S II] emission lines arise in a compact (≤ 1″4) probably non-spherical region which is identified with the ionized shell of M 3-27. The Hα emission from M 3-27 is dominated by strong emission from an ionized stellar wind and exhibits a Type III P Cygni profile with very extended wings (≃ 3000 km s–1). The estimated kinematic age and ionized mass of Cn 3-1 (≃ 1300 yr, 4 × 10–2 M⊙) and M 3-27 (≤ 530 yr, ≃ 3 × 10–4 M⊙) indicate that both objects are young planetary nebulae. Extended halos (size ≃ 36″ in Cn 3-1, ≃ 24″ in M 3-27) have been spectroscopically detected in both objects. An analysis of the kinematic and emission properties shows that both halos are reflection nebulosities and suggests that the distribution of neutral material in them probably is largely isotropic. The results suggest that the halos correspond to isotropic mass ejections occurred in the last ≃ 2 × 104 yr of the AGB phase of the Cn 3-1 and M 3-27 progenitors.

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Gómez Martín, J. C., J. Blahins, U. Gross, T. Ingham, A. Goddard, A. S. Mahajan, A. Ubelis y A. Saiz-Lopez. "In situ detection of atomic and molecular iodine using resonance and off-resonance fluorescence by lamp excitation: ROFLEX". Atmospheric Measurement Techniques Discussions 3, n.º 4 (25 de agosto de 2010): 3803–49. http://dx.doi.org/10.5194/amtd-3-3803-2010.

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Abstract. We demonstrate a new instrument for in situ detection of atmospheric iodine atoms and molecules based on atomic and molecular resonance and off-resonance ultraviolet fluorescence excited by lamp emission. The instrument combines the robustness, light weight, low power consumption and efficient excitation of radio-frequency discharge light sources with the high sensitivity of the photon counting technique. Calibration of I2 fluorescence is achieved via quantitative detection of the molecule by incoherent broad band cavity-enhanced absorption spectroscopy. Atomic iodine fluorescence signal is calibrated by controlled broad band photolysis of known I2 concentrations in the visible spectral range at atmospheric pressure. The instrument has been optimised in laboratory experiments to reach detection limits of 1.2 pptv for I atoms and 20 pptv for I2, for S/N=1 and 10 min of integration time. The ROFLEX system has been deployed in a field campaign in Northern Spain, representing the first concurrent observation of ambient mixing ratios of iodine atoms and molecules in the 1–350 pptv range.

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Dietrich, M., P. T. O’Brien y K. M. Leighly. "First Results of Optical Monitoring of 3C 390.3". International Astronomical Union Colloquium 159 (1997): 163–64. http://dx.doi.org/10.1017/s0252921100039889.

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In late autumn 1994, the International AGN Watch started a multiwavelength monitoring campaign on 3C 390.3, the first radio-loud AGN to be selected for high temporal-resolution monitoring from the radio domain to X-ray energies. This AGN is is of particular interest since significant variations have been observed on both short and long time scales in both the line fluxes and line profiles (Barr et al. 1980, Veilleux & Zheng 1991).In the optical, spectroscopic data and broad-band flux measurements in B, V, R, and I were obtained. The brightness of 3C 390.3 was calculated relative to the stars in the field. The R magnitudes are based on observations recorded at Calar Alto, Spain, in 1994 December. Generally, AGN spectra are intercalibrated using narrow forbidden emission lines since these lines can be taken as constant on time scales of decades (Peterson 1993). Since the [O III] λλ4959, 5007 flux is variable on time scales of several months (Zheng et al. 1995), these lines were studied in detail. We found that they were constant within ~2% during 1995 (Dietrich et al. 1996). The spectra were therefore intercalibrated by using the narrow forbidden emission lines. 3C 390.3 was also observed with IUE for 14 months (O’Brien et al. 1996) and with ROSAT for nine months in 1995 (Leighly et al. 1996). Radio data were also obtained during a 3-month MERLIN campaign.

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Pović, Mirjana. "Development in astronomy in Ethiopia and East-Africa through nuclear activity in galaxies". Proceedings of the International Astronomical Union 15, S356 (octubre de 2019): 3–8. http://dx.doi.org/10.1017/s174392132000246x.

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AbstractIn this paper we summarise the research that is currently going on in Ethiopia and East-Africa in extragalactic astronomy and physics of active galaxies and active galactic nuclei (AGN). The study is focused on some of the still open questions such as: what are the stellar ages and populations of ultra hard X-ray detected AGN and connection between AGN and their host galaxies?, what are the properties of AGN in galaxy clusters and the role that environment has in triggering nuclear activity?, what are the morphological properties of AGN and how precisely we can deal with morphological classification of active galaxies?, what are the properties of galaxies in the green valley and the role of AGN in galaxy evolution?, and what are the properties of radio-loud and radio-quiet quasars (QSO) and dichotomy between the two?. Each of these questions has been developed under one specific project that will be briefly introduced. These projects involve 6 PhD and 3 MSc students and collaborations between Ethiopia, Rwanda, South Africa, Uganda, Tanzania, Spain, Italy, and Chile. With all projects we aim: first, to contribute to our general knowledge about AGN, and second, to contribute to the development in astronomy and science in Ethiopia and East-Africa.

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Llasat, M. C., T. Rigo, M. Ceperuelo y A. Barrera. "Estimation of convective precipitation: the meteorological radar versus an automatic rain gauge network". Advances in Geosciences 2 (2 de mayo de 2005): 103–9. http://dx.doi.org/10.5194/adgeo-2-103-2005.

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Abstract. The estimation of convective precipitation and its contribution to total precipitation is an important issue both in hydrometeorology and radio links. The greatest part of this kind of precipitation is related with high intensity values that can produce floods and/or damage and disturb radio propagation. This contribution proposes two approaches for the estimation of convective precipitation, using the β parameter that is related with the greater or lesser convective character of the precipitation event, and its time and space distribution throughout the entire series of the samples. The first approach was applied to 126 rain gauges of the Automatic System of Hydrologic Information of the Internal Basins of Catalonia (NE Spain). Data are series of 5-min rain rate, for the period 1996-2002, and a long series of 1-min rain rate starting in 1927. Rainfall events were classified according to this parameter. The second approach involved using information obtained by the meteorological radar located near Barcelona. A modified version of the SCIT method for the 3-D analysis and a combination of different methods for the 2-D analysis were applied. Convective rainfall charts and β charts were reported. Results obtained by the rain gauge network and by the radar were compared. The application of the β parameter to improve the rainfall regionalisation was demonstrated.

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Querol, Xavier, Andrés Alastuey, Gotzon Gangoiti, Noemí Perez, Hong K. Lee, Heeram R. Eun, Yonghee Park et al. "Phenomenology of summer ozone episodes over the Madrid Metropolitan Area, central Spain". Atmospheric Chemistry and Physics 18, n.º 9 (8 de mayo de 2018): 6511–33. http://dx.doi.org/10.5194/acp-18-6511-2018.

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Abstract. Various studies have reported that the photochemical nucleation of new ultrafine particles (UFPs) in urban environments within high insolation regions occurs simultaneously with high ground ozone (O3) levels. In this work, we evaluate the atmospheric dynamics leading to summer O3 episodes in the Madrid air basin (central Iberia) by means of measuring a 3-D distribution of concentrations for both pollutants. To this end, we obtained vertical profiles (up to 1200 m above ground level) using tethered balloons and miniaturised instrumentation at a suburban site located to the SW of the Madrid Metropolitan Area (MMA), the Majadahonda site (MJDH), in July 2016. Simultaneously, measurements of an extensive number of air quality and meteorological parameters were carried out at three supersites across the MMA. Furthermore, data from O3 soundings and daily radio soundings were also used to interpret atmospheric dynamics. The results demonstrate the concatenation of venting and accumulation episodes, with relative lows (venting) and peaks (accumulation) in O3 surface levels. Regardless of the episode type, the fumigation of high-altitude O3 (arising from a variety of origins) contributes the major proportion of surface O3 concentrations. Accumulation episodes are characterised by a relatively thinner planetary boundary layer (< 1500 m at midday, lower in altitude than the orographic features), light synoptic winds, and the development of mountain breezes along the slopes of the Guadarrama Mountain Range (located W and NW of the MMA, with a maximum elevation of > 2400 m a.s.l.). This orographic–meteorological setting causes the vertical recirculation of air masses and enrichment of O3 in the lower tropospheric layers. When the highly polluted urban plume from Madrid is affected by these dynamics, the highest Ox (O3+ NO2) concentrations are recorded in the MMA. Vertical O3 profiles during venting episodes, with strong synoptic winds and a deepening of the planetary boundary layer reaching > 2000 m a.s.l., were characterised by an upward gradient in O3 levels, whereas a reverse situation with O3 concentration maxima at lower levels was found during the accumulation episodes due to local and/or regional production. The two contributions to O3 surface levels (fumigation from high-altitude strata, a high O3 background, and/or regional production) require very different approaches for policy actions. In contrast to O3 vertical top-down transfer, UFPs are formed in the planetary boundary layer (PBL) and are transferred upwards progressively with the increase in PBL growth.

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Libros sobre el tema "Radio 3 (Spain)"

United States. Delegation to the World Administrative Radio Conference, 1992, Málaga-Torremolinos, Spain. World Administrative Radio Conference for Dealing with Frequency Allocations in Certain Parts of the Spectrum (WARC-92): Malaga-Torremolinos, Spain, February 3-March 3, 1992 : United States Delegation report. [Washington, D.C.]: U.S. Dept. of State, Bureau of the Coordinator for International Communication and Information Policy, 1992.

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US GOVERNMENT. Maritime matters: Agreement between the United States of America and Ukraine, signed at Washington December 3, 1992. Washington, D.C: Dept. of State, 1993.

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US GOVERNMENT. Joint financing of certain air navigation services in Greenland and Faroe Islands: Protocol between the United States of America and other governments, amending the agreement of September 25, 1956, as amended, done at Montreal November 3, 1982. Washington, D.C: Dept. of State : For sale by the Supt. of Docs., U.S. G.P.O., 1993.

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US GOVERNMENT. Investment treaty with Zaire: Message from the President of the United States transmitting the treaty between United States of America and the Republic of Zaire concerning the reciprocal encouragement and protection of investment, with protocol, signed at Washington, August 3, 1984. Washington: U.S. G.P.O., 1986.

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Sanchez, Mariano F. Radio 3: Rescate de Un Recuerdo. Espejo de Tinta, 2004.

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Radio 3: 20 años : una crónica de la cultura popular en España. Valencia: Ed. La Mascara, 1998.

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Radio emission from the stars and the sun: A conference held at the University of Barcelona, Barcelona, Spain, 3-7 July 1995. San Francisco, Calif: Astronomical Society of the Pacific, 1996.

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Capítulos de libros sobre el tema "Radio 3 (Spain)"

Pfenninger, Susanne, Herman Cho, Jörg Forrer y Arthur Schweiger. "Radio Frequency Driven Electron Spin Echo Envelope Modulation". En 25th Congress Ampere on Magnetic Resonance and Related Phenomena, 443–44. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-76072-3_230.

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Adekunle, Carl B. y Steve Schneider. "Detecting Feature Interactions in the Terrestrial Trunked Radio (TETRA) Network Using Promela and Xspin". En Theoretical and Practical Aspects of SPIN Model Checking, 136–51. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/3-540-48234-2_10.

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Sakai, H., T. Wakui, M. Hatano, A. Tamii y T. Uesaka. "Spin polarized solid proton target for experiments by the radio-isotope beam". En Exotic Nuclei and Atomic Masses, 487–88. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-642-55560-2_176.

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Geithner, W., S. Franchoo, S. Kappertz, K. Marinova y R. Neugart. "Nuclear spin and moments of 73Kr and odd—even staggering in the radii of light krypton isotopes". En Exotic Nuclei and Atomic Masses, 89. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-642-55560-2_29.

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Hawrylak, Peter J., George Louthan, Jeremy Daily, John Hal y Mauricio Papa. "Attack Graphs and Scenario Driven Wireless Computer Network Defense". En Situational Awareness in Computer Network Defense, 284–301. IGI Global, 2012. http://dx.doi.org/10.4018/978-1-4666-0104-8.ch016.

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This chapter describes how to use attack graphs to evaluate the security vulnerabilities of an embedded computer network and provides example cases of this technique. Attack graphs are powerful tools available to system administrators to identify and manage vulnerabilities. Attack graphs describe the steps an adversary could take to reach a desired goal and can be analyzed to quantify risk. The systems investigated in this chapter are embedded systems that span hardware, software, and network communication. The example cases studied will be (1) radio frequency identification (RFID), (2) vehicle networks, and (3) the Smart Grid (the next generation power and distribution network in the USA).

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"Conservation, Ecology, and Management of Catfish: The Second International Symposium". En Conservation, Ecology, and Management of Catfish: The Second International Symposium, editado por GREGORY T. GELWICKS y GREGORY A. SIMMONS. American Fisheries Society, 2011. http://dx.doi.org/10.47886/9781934874257.ch37.

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Abstract.—A radio-telemetry study was initiated in August 2004 to determine extent and timing of flathead catfish Pylodictis olivaris movements in the Iowa River, Iowa. Between 2004 and 2007, 56 flathead catfish were radio-tagged in the Iowa River between the Mississippi River and the lowermost dam at Iowa City, Iowa. Fish tagged for this study were collected during prespawn/spawn (mid-April to mid-July) and summer/fall (late-July to mid-October) periods at three sites. Radio-tagged fish were tracked through September 2009; fish included in our analyses were located 3–31 times and were tracked for 92–1,554 d. While some fish remained near original tagging locations, others made long distance movements associated with overwintering and spawning. Total linear range varied from 0.5 to 120 km with a mean of 42.4 ± 6.1 (mean ± SE) km, and there were no significant correlations between total linear range and fish length or age. There was no significant difference in total linear range of fish related to tagging period. However, seasonal movement patterns indicated that timing of sampling may affect population characteristics observed at the reach level in the Iowa River. Fish tracked for multiple years exhibited a high degree of fidelity for seasonal locations, particularly during summer/fall and overwintering periods. In addition to telemetry results, harvest of radio-tagged fish in the English and Mississippi rivers indicates that a larger scale than the reach, or Iowa River main stem, should be considered in management of flathead catfish in the Iowa River.

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Actas de conferencias sobre el tema "Radio 3 (Spain)"

Aldawood, Ali, Ibrahim Hoteit, Abdulrahman Alshuhail y Abdullatif Al-Shuhail. "Enhancing the signal-to-noise ratio of sonic waveforms by Interferometric stacking". En International Conference and Exhibition, Barcelona, Spain, 3-6 April 2016. Society of Exploration Geophysicists and American Association of Petroleum Geologists, 2016. http://dx.doi.org/10.1190/ice2016-6440588.1.

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Repko, Timothy W., Andrew C. Nix y James D. Heidmann. "A Parametric Numerical Study of the Effects of Freestream Turbulence Intensity and Length Scale on Anti-Vortex Film Cooling Design at High Blowing Ratio". En ASME 2013 Heat Transfer Summer Conference collocated with the ASME 2013 7th International Conference on Energy Sustainability and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/ht2013-17255.

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An advanced, high-effectiveness film-cooling design, the anti-vortex hole (AVH) has been investigated by several research groups and shown to mitigate or counter the vorticity generated by conventional holes and increase film effectiveness at high blowing ratios and low freestream turbulence levels. [1, 2] The effects of increased turbulence on the AVH geometry were previously investigated and presented by researchers at West Virginia University (WVU), in collaboration with NASA, in a preliminary CFD study [3] on the film effectiveness and net heat flux reduction (NHFR) at high blowing ratio and elevated freestream turbulence levels for the adjacent AVH. The current paper presents the results of an extended numerical parametric study, which attempts to separate the effects of turbulence intensity and length-scale on film cooling effectiveness of the AVH. In the extended study, higher freestream turbulence intensity and larger scale cases were investigated with turbulence intensities of 5, 10 and 20% and length scales based on cooling hole diameter of Λx/dm = 1, 3 and 6. Increasing turbulence intensity was shown to increase the centerline, span-averaged and area-averaged adiabatic film cooling effectiveness. Larger turbulent length scales were shown to have little to no effect on the centerline, span-averaged and area-averaged adiabatic film-cooling effectiveness at lower turbulence levels, but slightly increased effect at the highest turbulence levels investigated.

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Zhao, Qingjun, Huishe Wang, Fei Tang, Xiaolu Zhao y Jianzhong Xu. "Influence of Hot Streak/Airfoil Count Ratios on High Pressure Stage of a Vaneless Counter-Rotating Turbine". En ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-50542.

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In order to reveal the effects of the hot streak/airfoil count ratio on the heating patterns of high pressure turbine rotor blades in a Vaneless Counter-Rotating Turbine, three-dimensional unsteady Navier-Stokes simulations have been performed. In these simulations, the ratio of the number of hot streaks to the number of the high pressure turbine vanes and rotors is 1:3:3, 1:2:2, 2:3:3 and 1:1:1, respectively. The numerical results show that the migration characteristics of the hot streak in the high pressure turbine rotor are predominated by the combined effects of secondary flow and buoyancy. The combined effects induce the high temperature fluid migrate towards the hub in the high pressure turbine rotor. And the combined effects become more intensified when the hot streak/airfoil count ratio increases. The results also indicate that the peak temperature of the hot streak is dissipated as the hot streak goes through the high pressure turbine vane or the rotor. The dissipated extent of the peak temperature in the high pressure turbine stator and the rotor is increased as the hot streak-to-airfoil ratio increases. And the increase of the hot streak/airfoil count ratio trends to increase the relative Mach number at the high pressure turbine outlet. The relative flow angle from 23% to 73% span at the high pressure turbine outlet decreases as the hot streak-to-airfoil ratio increases. The results also indicate that the isentropic efficiency of the Vaneless Counter-Rotating Turbine is decreased as the hot streak/airfoil count ratio increases.

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Mirzaei, Farhad. "An Extension to “Allowable Design Factor” Method for Free Span Calculation of Sub Sea Pipelines". En ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-13184.

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Using the design factors is a traditional method in solid mechanics design. This method is still also the base of some design standards in the world [1,2].In this paper, a modification has been performed to traditional Von Misses stress check method for the calculation of sub sea pipeline free spanning. The DNV OS F101 which is a well known standard for sub sea pipelines has been used for calibration [3]. A spread sheet type program for free span calculation has been developed for "Force Model" which facilitates the evaluation of the free span length based on the latest DNV proposed method as well as traditional Von Misses stress check. The method statement is the calculation of maximum allowable sub sea pipeline free span, by DNV proposed method and consequently evaluation of allowable stress to result the same free span length in Von Misses traditional method. The design factors which are the Stress Factors (SF) will be calculated by the ratio of existing equivalent Von Misses stress to yield strength of the pipeline material (fy).

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Bai, Jiang-Tao, Hui-ren Zhu y Cun-liang Liu. "Film Cooling Characteristic of Double-Fan-Shaped Film Cooling Holes". En ASME Turbo Expo 2009: Power for Land, Sea, and Air. ASMEDC, 2009. http://dx.doi.org/10.1115/gt2009-59318.

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The film cooling performance downstream of a single row of double-fan-shaped film cooling holes in a flat plate have been investigated by experimental measurements and numerical simulation. The entrance and exit of double-fan-shaped holes are comprised of a lateral expansion of 15° from the original simple cylindrical shape with stream-wise inclination of 45°. The width of the exit face to cylinder diameter ratio is 1.5; the length-to-diameter ratio is 4.24 and the pitch-to-diameter ratio is 3. The experimental method used to obtain the adiabatic film cooling effectiveness values and the heat transfer coefficient is a transient narrow band liquid crystal technique. Both film cooling effectiveness and heat transfer coefficient are measured at three momentum ratios (I = 0.5, 1, 2) at constant Reynolds number (Re = 10000) and free stream turbulence (Tu = 2%). The film cooling effectiveness, heat transfer coefficient and Net Heat Flux Reduction (NHFR) are presented for detailed distribution and span-wise averaged values. Discharge coefficients are also measured in the experiment. A commercial package is used to numerically simulate the flow and heat transfer of double-fan-shaped holes; simple cylindrical holes are also simulated for comparison. Numerical simulation use RNG turbulence model with a standard wall function for near wall region. Experimental and Numerical simulation results show that: 1) the double-fan-shaped holes present higher discharge coefficient than simple cylindrical holes at respective momentum ratio; 2) the numerical simulation film cooling effectiveness results of double-fan-shaped holes accord well with the experimental results; 3) at measured three momentum ratios, the double-fan-shaped holes demonstrate better film cooling performance (higher NHFR) than simple cylindrical holes, better film cooling expansion on span-wise; 4) the best momentum ratio of double-fan-shaped holes is 0.5.

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Rafeeq, Mudassir Ahmed M., Quamber H. Nagpurwala y Subbaramu Shivaramaiah. "Numerical Studies on the Effect of Gurney Flap on Aerodynamic Performance and Stall Margin of a Transonic Axial Compressor Rotor". En ASME 2014 Gas Turbine India Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gtindia2014-8130.

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Numerical studies have been carried out on the effectiveness of trailing edge Gurney flap on a transonic axial compressor rotor. The baseline geometry of the rotor blade was modified at the trailing edge by introducing Gurney flaps of varying depth and span-wise length, viz. 1 mm, 2 mm and 3 mm depth with 20% span length of Gurney flap from tip (designated as GF1-20, GF2-20 and GF3-20 respectively), and 1 mm depth with 50% and 100% span length (designated as GF1-50 and GF1-100 respectively). Geometric models of the compressor rotor without and with Gurney flaps were generated using CATIA V5 software and CFD simulations at 100% design rotor speed were carried out using ANSYS CFX software. Results have shown that the compressor total pressure ratio increased with increase in both depth and spanwise length of Gurney flap. Peak pressure ratio increased from 1.51 for baseline case to 1.58 for rotor GF1-100. However, the peak isentropic efficiency remained almost constant for various Gurney flap configurations, except for GF1-100 which showed a tendency for improvement in efficiency. The stall margin reduced with the introduction of Gurney flap and was lowest for configuration GF1-100 which gave highest peak pressure ratio. Higher blade loading with Gurney flap was responsible for lowering the stall margin. Analysis of the flow through the blade passages has shown clear formation of trailing end vortex structure in the presence of Gurney flap that resulted in bending of the streamlines towards suction surface of the rotor blade, with consequent reduction in flow deviation and increased flow deflection, and hence increased total pressure ratio.

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Hwang, E. S., M. T. Hwang, D. Y. Kim y K. J. Park. "Proposed evaluation methods for vibration serviceability of long span cable bridges". En IABSE Congress, Christchurch 2021: Resilient technologies for sustainable infrastructure. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2021. http://dx.doi.org/10.2749/christchurch.2021.0327.

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Vibration serviceability becomes more important considerations in design and maintenance, especially for slender and flexible structures such as long span cable bridges. In this study, various evaluation methods for vibration serviceability for long span cable bridges are proposed. These methods are based on short and long-term monitoring data such as accelerations and displacements of bridges. Proposed methods include (1) method of evaluating vibration amplitude based on Reiher-Meister curves, (2) method of evaluating variations in natural frequencies and damping ratio,(3) method of weighted rms(root-mean-square) acceleration based on ISO 2631-1, and (4) probabilistic analysis using long-term monitoring data. These methods are applied to example cable bridge and cases of normal traffic, heavy traffic, windy condition and sudden abnormal vibration are considered. The results of this study are expected to be implemented to real bridge monitoring system for real-time and periodic evaluation of vibration serviceability.

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Morton, Chris y Serhiy Yarusevych. "Vortex Shedding From Low Aspect Ratio Dual Step Cylinders". En ASME 2012 Fluids Engineering Division Summer Meeting collocated with the ASME 2012 Heat Transfer Summer Conference and the ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/fedsm2012-72178.

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A low aspect ratio dual-step cylinder is comprised of two cylinders of different diameters (D and d). The large diameter cylinder (D) with low aspect ratio (L/D) is attached to the mid-span of a small diameter cylinder (d). This geometry is relevant to many engineering applications, e.g., finned-tube heat exchangers, underwater cables, and cylindrical support structures. The present study investigates the effect of Reynolds number (ReD) and L/D on dual step cylinder wake development for 1050 ≤ ReD ≤ 2100, D/d = 2, and 0.2 < L/D ≤ 3. Experiments have been performed in a water flume facility utilizing flow visualization, Laser Doppler Velocimetry (LDV), and Particle Image Velocimetry (PIV). The results show that vortex shedding occurs from the large and small diameter cylinders at distinct frequencies for L/D ≥ 1 & ReD = 2100 and L/D ≥ 2& ReD = 1050. At these higher aspect ratios investigated, large cylinder vortices predominantly form closed vortex loops in the wake and small cylinder vortices form half-loop vortex connections. In contrast, at lower aspect ratios, vortex shedding from the large cylinder ceases, with the dominant frequency centred-activity in the large cylinder wake attributed to the passage of vortex filaments connecting small cylinder vortices. The presence of the large cylinder distorts the vortex filaments causing cyclic vortex dislocations accompanied by the formation of half-loop vortex connections. Increasing L/D decreases the frequency of occurrence of vortex dislocations and increases the dominant frequency in the large cylinder wake. The results also show that the Reynolds number has a substantial effect on wake vortex shedding frequency, which is more profound than that expected for a uniform cylinder.

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Boyle, Robert J., Pritheesh Gnanaselvam, Ankur H. Parikh, Ali A. Ameri, Jeffrey P. Bons y Vinod K. Nagpal. "Design of Stress Constrained SiC/SiC Ceramic Matrix Composite Turbine Blades". En ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-15067.

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Abstract The structural and aerodynamic performance of a a low aspect ratio SiC/SiC CMC High Pressure Turbine blade was determined. The application was a NASA notional single aisle aircraft engine to be available in the N+3, beyond 2030, time frame. The notional rpm was maintained, and to satisfy stress constraints the annulus area was constrained. This led to a low span blade. For a given clearance low span blade are likely to have improved efficiency when shrouded. The efficiency improvement due to shrouding was found to strongly depend on the axial gap between the shroud and casing. Axial gap, unlike clearance or reaction, is not a common parameter used to correlate the efficiency improvement due to shrouding. The zero clearance stage efficiency of the low aspect ratio turbine was 0.920. Structural analyses showed that the rotor blade could be shrouded without excessive stresses. The goal was to have blade stresses less than 100 MPa (14.5 ksi) for the unshrouded blade. Under some not very restrictive circumstances, such as blade stacking, a one-dimensional radial stress equation accurately predicted area averaged Von Mises stress at the blade hub. With appropriate stacking radial and Von Mises stresses were similar.

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Evans, Simon, Junsok Yi, Sean Nolan, Liselle Joseph, Michael Ni y Sameer Kulkarni. "Modeling of Axial Compressor With Large Tip Clearances". En ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-14496.

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Abstract In the drive for lower fuel consumption through increased bypass ratio and increased overall pressure ratio (OPR), engine designs for the next generation of single-aisle aircraft will require core sizes below 3 lb/s and OPRs above 50. Traditionally, these core sizes are the domain of centrifugal compressors, but materials limit pressure ratio in these machines to well below 50. An all-axial high pressure compressor (HPC) at this core size, however, comes with limitations associated with the small blade spans at the back of the HPC, as clearances, fillets and leading edges do not scale with the core size. The result is a substantial efficiency penalty, driven primarily by the tip leakage flow produced by the larger clearance-to-span ratio, which negates the cycle efficiency benefits of the high OPR. In order to enable small-core, high-OPR, all-axial compressors mitigating technologies need to be developed and implemented to reduce the large clearance-to-span efficiency penalty. However, for this technology development to be successful, it is imperative that predictive design tools accurately model the overall flow physics and trends of the technologies developed. In this paper we describe an effort to determine whether different modeling standards are required for a large clearance-to-span ratio, and if so, identify criteria for an appropriate solver and/or mesh. Multiple models are run and results compared with data collected in the NASA Glenn Research Center’s Low-Speed Axial Compressor. These comparisons show that steady Reynolds-Averaged Navier-Stokes (RANS) solvers can predict the pressure-rise characteristic to an acceptable level of accuracy, if careful attention is paid to mesh topology in the tip region. However, unsteady tools are necessary to accurately capture radial profiles of blockage and total pressure. The Delayed-Detached Eddy Simulation model was also used to run this geometry, but did not resolve any additional features not captured by the unsteady RANS simulation near stall.

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MECHANICAL BEHAVIOR AND CATENARY ACTION OF RESTRAINED STEEL BEAM UNDER FIRE. The Hong Kong Institute of Steel Construction, septiembre de 2021. http://dx.doi.org/10.18057/ijasc.2021.17.3.8.

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To investigate the mechanical behavior and catenary action of restrained steel beam under fire, experiments were performed on five H-section restrained steel beams exposed to ISO-834 standard fire. At first, mechanical property tensile tests were performed on 3 room-temperature specimens and 8 high-temperature specimens, and variation laws of the material properties of steel materials with temperature rising were investigated by the high-temperature steady-state tests. Through the fire experiments, the temperature data, mid-span deflections and failure modes of all specimens were obtained. The experimental results show that: (1) a restrained steel beam is prone to in-plane buckling failure under fire; (2) the loading ratio n and axial restraint stiffness Kx have great influences on the catenary action of restrained steel beam under fire; (3) when the loading ratio n is constant, the greater the axial restraint stiffness Kx, the later the catenary action occurs; when the axial restraint stiffness Kx is constant, the greater the loading ratio n, the earlier the catenary action occurs.

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