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41.
Atilla Bayram 《Ocean Engineering》2000,27(4)
The aim of this study was to evaluate the performance of a sloping float (or inclined pontoon) breakwater with respect to expected wave climate for protection of small commercial vessels and yatch marinas. A two-dimensional model study was carried out for regular waves in intermediate water depths. The experimental results showed that the transmission coefficient was relatively insensitive to wave height and that it consistently increased as the wave period decreased. The performance of this type of breakwater was found to be promising for intermediate water depths. 相似文献
42.
Nazan Atilla 《Marine Ecology》2000,21(1):69-83
Abstract. Artificial substrates were used to investigate the cryptic meiofauna of a Louisiana estuary. Three types of collectors were used as artificial habitats in colonization studies. Mesh collectors (composed of a plastic thread, approximately 74 m long, woven into a pad) and bottle brushes (with approximately 4400 plastic bristles per brush, each 2.5 mm long) were colonized equally well by meiofauna; Hester-Dendy plates with less structural complexity were colonized at a slower rate, especially by copepods. Nematodes and harpacticoid copepods were always the two most abundant meiofaunal taxa collected. Mesh collectors were retrieved in July and December after a 2-week colonization period to examine seasonal trends. Starting in December, a long-term colonization study was also performed to determine if an equilibrium abundance could be achieved; artificial substrates were collected after 2, 4 and 8 weeks. Meiofauna achieved high abundances (means ranged from 1000 – 20,000 individuals per collector) on artificial substrates regardless of season, and abundance was related to supply, water flow and capture efficiency of the substrates as well as behavior of the meiofauna. Copepod species diversity was low (6 species were observed in July and 11 in December). Diversity and evenness were significantly different between July and December, and among the three collections in the long-term study. The copepod species assemblage qualitatively differed between July and December. Our data suggest that an abundant and dynamic but understudied meiofaunal assemblage is present in this estuarine embayment. This assemblage is not associated with macroalgae but rather related to presence of hard substrates and seasonally abundant filamentous microalgae. 相似文献
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Havvanur K&#x;l&#x; Pelin Tohumcu
zener Atilla Ansal Mustafa Y&#x;ld&#x;r&#x;m Kutay
zayd&#x;n enol Adatepe 《Engineering Geology》2006,86(4):238-255
A microzonation study is performed as a part of the Zeytinburnu Pilot Project within the framework of the Earthquake Master Plan for Istanbul to determine the effects of local soil conditions on the earthquake forces that will act on structures. For this purpose, detailed geological and geotechnical studies are conducted at the site, a geological map which demonstrates the local geological features of the site is prepared, and the site is classified with respect to the dynamic behaviour based on the data gathered from the soil borings. In order to investigate the effects of local soil conditions on the dynamic behaviour, site response analyses are performed with the computer code EERA by utilizing the findings of field and laboratory investigations. The behaviour of the region during a probable earthquake is investigated through one dimensional response analyses and microzonation maps are prepared with respect to ground shaking intensity in accordance with the new microzonation manual [Ansal, A., Laue, J., Buchheister, J., Erdik, M., Springman, S., Studer, J., and Koksal, D., 2004. “Site characterization and site amplification for a seismic microzonation study in Turkey” 11th Int. Conference on Soil Dynamics and Earthquake Engineering and 3rd Earthquake Geotechnical Engineering, San Francisco; Studer, J. and Ansal, A., 2004. Belediyeler için Sismik Mikrobölgeleme El Kitabı, Araştırma Raporu, Afet İşleri Genel Müdürlüğü, Bayındırlık ve İskan Bakanlığı, Afet Risk Yönetimi Dünya Enstitüsü]. 相似文献
45.
Faults in porous sandstones occur in three forms: deformation bands about 1-mm thick and tens of m long and across which offsets are a few mm; zones of deformation bands constituted of many closely spaced deformation bands across which offsets are a few cm or dm; and slip surfaces, that is, distinct surfaces within zones of deformation bands across which offsets are a few m to a few tens of m. Deformation bands represent highly localized deformation; analogous localization within a field of homogeneous deformation is theoretically possible in inelastic materials with certain ranges of constitutive parameters. Crushing and consolidation of sandstone within a band cause the material there to become stiffer than the surrounding porous sandstone. A zone of deformation bands behaves mesoscopically much as a stiff inclusion in a soft matrix. According to the constitutive model assumed to investigate the formation of deformation bands, an instability can develop, and strain increments within the zone of deformation bands can become boundlessly large when the far-field stresses reach critical values. This instability is here associated with the formation of slip surfaces. 相似文献