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1.
Maria Alp Barbara L. Peckarsky Stefano M. Bernasconi Christopher T. Robinson 《Aquatic Sciences - Research Across Boundaries》2013,75(4):595-606
Stable isotopes (13C and 15N) are widely applied in studies of trophic links. We used this method to investigate the contribution of aquatic and terrestrial prey to the diet of riparian predatory arthropods in two mountain headwater streams in Colorado, USA. Aquatic and terrestrial prey and riparian predators were collected during summer 2009. To evaluate the reliability of conclusions based on stable isotope ratios, we compared the isotopic signatures of aquatic larval and terrestrial adult stages of three abundant stream insect species and assessed variation in mixing model estimates for spider diet composition under varying assumptions for trophic fractionation. Adult isotopic signatures of some aquatic prey species were indistinguishable from those of prey species with exclusively terrestrial life histories (stoneflies: 13C and 15N, chironomids: 13C). Other prey had distinctly aquatic isotopic signatures as both larvae and adults (a mayfly and a caddisfly). There was no evidence that prey with aquatic isotopic signatures contributed to the diet of the spiders near one stream. For the other stream, mixing model analysis suggested that chironomids were included in the diets of lycosid, linyphiid and liocranid spiders. Reliable estimates of the contributions of prey sources were compromised by the sensitivity of mixing models to assumptions on trophic fractionation and the presence of “isotopically cryptic” prey. This study emphasizes the importance of supporting isotope-based studies on cross-boundary trophic links with data on isotopic shifts in prey with complex life cycles and assessment of fractionation rates specific to the study system. 相似文献
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Yılmaz Muhammet Alp Harun Tosunoğlu Fatih Aşıkoğlu Ömer Levend Eriş Ebru 《Natural Hazards》2022,110(2):1039-1060
Natural Hazards - Environmental changes have led to non-stationary flood risks in coastal cities. How to quantitatively characterize the future change trend and effectively adapt is a critical... 相似文献
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In this study, the removal of free cyanide from aqueous solutions by activated carbon was investigated. Effects of metal impregnation (Cu and Ag), aeration, and concentrations of adsorbent and cyanide on the rate and extent of the removal of cyanide were studied. The results have shown that the capacity of activated carbon for the removal of cyanide can be significantly improved (up to 6.3-fold) via impregnation of activated carbon with metals such as copper and silver. Silver-impregnated activated carbon was found to be the most effective at the reduction of cyanide level in solution. This appeared to be coupled with its comparatively high metal content after impregnation process where silver (5.07%) could be more readily loaded on activated carbon than copper (0.43%). Kinetics and equilibrium data for cyanide removal by plain and metal-impregnated activated carbons were determined to be consistent with the pseudo second-order kinetics and the Langmuir adsorption isotherms, respectively. Aeration (0.27 l/min) was found to exert a profound effect on the process leading to a 5.5–49.1% enhancement in the performances of plain and metal-impregnated activated carbons. This enhancement could be attributed to the increase in the availability of active sites on activated carbon for adsorption and the catalytic oxidising activity of activated carbon in the presence of oxygen. Practical limiting capacity of plain, copper- and silver-impregnated activated carbons for the removal of cyanide were experimentally determined to be 19.7, 22.4 and 29.6 mg/g, respectively. 相似文献
4.
Comparison of fundamental properties of new types of fiber‐mesh‐reinforced seismic isolators with conventional isolators 
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下载免费PDF全文 New types of fiber‐reinforced rubber‐based seismic isolators have been a research interest for a number of engineers in the past decade. These new types of isolators can have similar seismic performances compared with the conventional ones. In most of the previous researches, the fiber‐reinforced rubber‐based isolators is usually manufactured with placing fiber sheets between precut rubber layers with the use of a bonding agent. This research differs from the previous researches in terms of manufacturing process, use of fiber mesh instead of fiber sheets, and use of lead in the core for some of the bearings. The aim of this research is to provide comparisons in fundamental seismic response properties of the new type of fiber mesh reinforced isolators and conventional isolators. In this scope, four pairs of fiber mesh reinforced elastomeric bearings and four pairs of steel‐reinforced elastomeric bearings are subjected to various levels of compression stresses and cyclic shear strains under constant vertical pressure. The tested types of isolators are fiber mesh reinforced elastomeric bearing, fiber mesh reinforced elastomeric bearing with lead core, steel‐reinforced elastomeric bearings, and steel‐reinforced elastomeric bearings with lead core. In this research, steel‐reinforced bearings are called conventional isolators. The major advantage for fiber mesh reinforced bearings observed during the tests is that these isolators can develop a considerable low horizontal stiffness compared with the conventional isolators. The damping characteristics of the new and conventional types are similar to each other. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Asude Hanedar Kadir Alp Burcak Kaynak Jaemeen Baek Edip Avsar M. Talat Odman 《Atmospheric Research》2011,99(3-4):391-399
The chemical mass balance model was applied to atmospheric Polycyclic Aromatic Hydrocarbons (PAHs) in Istanbul, Turkey. A total of 326 airborne samples were collected and analyzed for 16 PAHs and Total Suspended Particles (TSP) in the September 2006–December 2007 period at three monitoring stations: Yildiz, DMO (urban sites) and Kilyos (rural site). The total average PAH concentrations were 100.66 ± 61.26, 84.63 ± 46.66 and 25.12 ± 13.34 ng m?3 and the TSP concentrations were 101.16 ± 53.22, 152.31 ± 99.12, 49.84 ± 18.58 μg m?3 for Yildiz, DMO and Kilyos stations respectively. At all the sites, the lighter compounds were the most abundant, notably Nap, AcPy and PA. The average correlation values between TSP and total heavier PAH were greater than 0.5 for Yildiz and DMO stations. The patterns of PAH and TSP concentrations showed spatial and temporal variations. PAH concentrations were evaluated for the PAH contribution from four sources (diesel engines, gasoline engines, natural gas combustion, and coal + wood burning). Vehicle emissions appear to be the major source with contributions of 61.2%, 63.3% and 54.1% for Yildiz, DMO and Kilyos stations respectively. Seasonal and yearly variations had different trends for all sites. 相似文献
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D. Civile E. Lodolo H. Alp Z. Ben-Avraham A. Cova L. Baradello D. Accettella M. Burca J. Centonze 《Marine Geophysical Researches》2014,35(1):37-53
Within the central Mediterranean, the northwestern sector of the Sicily Channel is the unique area where two independent tectonic processes can be analyzed: the building of the Sicilian–Maghrebian Chain occurred in Late Miocene and the continental lithospheric rifting of the northern African margin occurred since Early Pliocene. These two geodynamic processes generated a peculiar structural style that is largely recognizable in the Adventure Plateau. This plateau is the shallowest part of the Sicily Channel, where water depths do not generally exceed 150 m. It hosts several areas of geomorphic relief, which in some cases rise up to less than 20 m beneath sea-level. A series of submarine magmatic manifestations occur in this area, mainly associated with the extensional phase which produced the rift-related depressions of Pantelleria, Malta and Linosa. Seismic-stratigraphic and structural analyses, based on a large set of multichannel seismic reflection profiles and well information acquired mostly for commercial purposes in the 1970s and 1980s, have allowed us to reconstruct the Triassic-Quaternary sedimentary succession of the Adventure Plateau and define its structural setting. A broad lithological distinction can be made between the successions ranging from Triassic to Paleogene, predominantly carbonate, and the successions ranging from Miocene to Quaternary, predominantly siliciclastic. Three main structural belts have been identified within the Adventure Plateau: (1) the northern belt, affected during Late Miocene time by ESE-verging thrusts belonging to the External Thrust System orogenic domain, which represents the lowermost structural level of the Sicilian–Maghrebian Orogen; (2) the Apenninic–Maghrebian domain of the Sicilian–Maghrebian Orogen, which occupies the northwestern sector of the Adventure Plateau, and that is overthrusted on the External Thrust System orogenic domain during the Late Miocene; (3) the extensional belt of the southwestern sector of the Adventure Plateau, affected by broad NW-trending, high-angle normal faults associated with the Early Pliocene continental rifting phase. The eastern boundary of the Adventure Plateau corresponds to a broadly N–S trending lithospheric transfer zone separating two sectors of the Sicily Channel characterized by a different tectonic evolution. 相似文献
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Hakan Alp 《Geo-Marine Letters》2014,34(5):447-455
A total of 42 km of high-resolution seismic reflection and bathymetric data were collected for the first time to document stratigraphic and structural features of the uppermost 5 m of the Holocene sedimentary infill of Küçükçekmece Lagoon along the Marmara Sea coast of Turkey. The lagoon gradually deepens from 1 m off the northern coast to a maximum of 20 m in the southern basin. Stratigraphically, the uppermost seismic unit is characterized by a generally parallel reflection configuration, indicating deposition under low-energy conditions. In the southern basin of the lagoon, the sub-bottom is locally characterized by frequency attenuated and chaotic reflections interpreted as gas-charged sediments. Structurally, the soft sediment of the first 5 m below the lagoon floor is locally deformed by active strike-slip fault zones, here named FZ1, FZ2, and FZ3. These fault zones are NW–SE oriented and follow the long axis of the lagoon, compatible with the geographic alignment of the lagoon, the onland drainage pattern, and the scarps of the surrounding terrain. Moreover, the fault zones in Küçükçekmece Lagoon are well correlated with active offshore faults mapped during previous studies. This suggests that the FZ1, FZ2, and FZ3 fault zones are not merely local fault systems deforming the Küçükçekmece Lagoon bottom, but that they may be part of a regional fault zone extending both north and southward to merge with the northern branch of the North Anatolian Fault Zone (NAFZ) in the Ç?narc?k Basin. This, however, needs to be confirmed by further structural and seismological studies around Küçükçekmece Lagoon in order to more firmly establish its link with the NAFZ in the Marmara Sea, and to highlight potential seismic risks for the densely populated Istanbul metropolitan area. 相似文献
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C. Gokceoglu M.C. Tunusluoglu T. Gorum H. Tur E. Gokasan A.B. Tekkeli F. Batuk H. Alp 《Engineering Geology》2009,106(3-4):133-153
Seismic and multi-beam bathymetric data from the northern shelf and slope of the Cinarcik Basin, which is generated by the North Anatolian Fault Zone (NAFZ) located in the easternmost basin in the Marmara Sea, were re-interpreted to better understand the future sub-marine landslide susceptibility. Seismic data indicate that upper surface of the sub-marine extension of the Paleozoic rocks has an NNE–SSW oriented basin and a ridge type morphology controlled by the secondary faults of the NAFZ. Basins are fulfilled by Plio-Quaternary sediments, which are cut by strike-slip faults on the shelf and slope. The thickness of basin deposits reaches up to 130 m toward the linear northern slope of the Cinarcik Basin. A relatively recent sub-marine landslide, the Tuzla Landslide, cuts the slope of the Cinarcik Basin. The detailed morphological investigation indicates that the Tuzla Landslide is a deep-seated rotational landslide, which was likely triggered by activity of the NAFZ. Morphological analyses also indicate that the thick Plio-Quaternary deposits on the Paleozoic basement slid during the Tuzla Landslide event. This landslide is considered as a key event to understand the dynamics of the potential landslides on the northern shelf and slope of the Cinarcik Basin. Two areas locating on the eastern and the western sides of the Tuzla Landslide are considered as the potential areas for future sliding due to similarities of geological and geomorphological features with the Tuzla Landslide such as similar thick Plio-Quaternary deposits, similar slope morphology, and similar fault activity cutting the sediments. Considering this information, the purposes of the present study are to determine the dynamics of the possible landslide areas and to discuss their effects on the sub-marine morphology. In the light of the interpretations, the amounts of possible displaced material are obtained. Three different landslide scenarios due to possible slide surfaces for future landslides are developed and assessed. The first scenario is sliding of the sediments at the shelf break. The third scenario is a mass movement of almost whole basin deposits on the Paleozoic rocks. The latter one is evaluated as less important because of the volume of the displaced material, and the latter one is accepted as lowest possible event. Among the scenarios, the second scenario is accepted as the most critical and possible because of the amount of the slipped material and existence of faults rupture, which is considered as further sliding surfaces. These landslides will result in important changes in shelf, slope and basin floor in the study area. 相似文献
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High-resolution seismic data shed light on latest Pleistocene and Holocene sedimentation beneath the Büyükçekmece Bay, northern shelf area of the Marmara Sea, Turkey. Discontinuous fluvio-marine and marine deposits overlying the erosional truncation surface of Oligocene–Lower Miocene deposits are as thick as 30 m and preserved preferentially within the incised valleys that were controlled by some old faults. A series of prograding shoreline, laterally passing to the latest Pleistocene–Holocene valley-fill deposits, are thought to have accumulated mainly during times of shoreline transgression and sea-level rise. The overall morphology and stratigraphic setting observed in the Büyükçekmece Bay and at the southern outlet of the Bosphorus Strait have nearly same characteristics, implying that similar hydrodynamic conditions, erosional and depositional processes were mainly under the control of strong northerly flows during the Late Quaternary. These flows were less powerful in the Büyükçekmece region with decreased sediment input and smaller accommodation space. 相似文献