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Arabian Journal of Geosciences - The increasing availability of 3D seismic data and well logs from Ash Shaer Area has provided fundamental new insights into the Miocene igneous activity and its... 相似文献
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Natural Hazards - Cut slope surfaces are affected by excavation activities and weathering agents. Disturbances on the surface can penetrate down to a certain depth. Slope stability analyses made on... 相似文献
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Taskin Kavzoglu Hasan Tonbul Merve Yildiz Erdemir Ismail Colkesen 《Journal of the Indian Society of Remote Sensing》2018,46(8):1297-1306
Object-based image analysis (OBIA) has attained great importance for the delineation of landscape features, particularly with the accessibility to satellite images with high spatial resolution acquired by recent sensors. Statistical parametric classifiers have become ineffective mainly due to their assumption of normal distribution, vast increase in the dimensions of the data and availability of limited ground sample data. Despite pixel-based approaches, OBIA takes semantic information of extracted image objects into consideration, and thus provides more comprehensive image analysis. In this study, Indian Pines hyperspectral data set, which was recorded by the AVIRIS hyperspectral sensor, was used to analyse the effects of high dimensional data with limited ground reference data. To avoid the dimensionality curse, principal component analysis (PCA) and feature selection based on Jeffries–Matusita (JM) distance were utilized. First 19 principal components representing 98.5% of the image were selected using the PCA technique whilst 30 spectral bands of the image were determined using JM distance. Nearest neighbour (NN) and random forest (RF) classifiers were employed to test the performances of pixel- and object-based classification using conventional accuracy metrics. It was found that object-based approach outperformed the traditional pixel-based approach for all cases (up to 18% improvement). Also, the RF classifier produced significantly more accurate results (up to 10%) than the NN classifier. 相似文献
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Genetic transformation is gaining importance for developing plant types suitable to metal accumulate and/or hyperaccumulate. In this study, the transgenic tobacco plant which transferred the ScMTII gene from Saccharomyces cerevisiae to wild type tobacco cultivar Petite Havana (SR1) was grown on soils with low and high cadmium (Cd) and zinc (Zn) concentrations in a growth chamber for 6 weeks and compared to wild type tobacco for Cd and Zn accumulation. Cadmium and Zn accumulations in the transgenic and wild type tobacco plants were increased with the increasing Cd and Zn concentrations. Unlike Zn, the transgenic plant accumulated significantly higher amount of Cd compared to the wild type control plants. Shoot Cd concentrations of transgenic tobacco in higher Cd dosages reached the above the hyperaccumulation threshold value of 100 mg Cd kg?1 in the dry weight (DW). Transgenic tobacco accumulated 354, 400, 372, and 457 mg Cd kg?1 DW, for 10, 20, 40, and 80 mg Cd kg?1 soil treatments, respectively. These values are 3.5–4.5‐fold higher than that of Cd hyperaccumulation threshold value. With 10 mg kg?1 Cd treatment, the bioconcentration factor (BCF) of transgenic tobacco plants for Cd reached up to 35 in which the threshold value for BCF should be at least 10. Our results showed that the transgenic tobacco may be used as a good Cd hyperaccumulator plant and for phytoextraction of Cd contaminated soils, but not for Zn. 相似文献
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Palaeo- and Neo-Tethyan-related magmatic and metamorphic units crop out in Konya region in the south central Anatolia. The Neotethyan assemblage is characterized by mélange and ophiolitic units of Late Cretaceous age. They tectonically overlie the Middle Triassic–Upper Cretaceous neritic to pelagic carbonates of the Tauride platform. The metamorphic sole rocks within the Konya mélange crop out as thin slices beneath the sheared serpentinites and harzburgites. The rock types in the metamorphic sole are amphibolite, epidote-amphibolite, garnet-amphibole schist, plagioclase-amphibole schist, plagioclase-epidote-amphibole schist and quartz-amphibole schist. The geochemistry of the metamorphic sole rocks suggests that they were derived from the alkaline (seamount) and tholeiitic (E-MORB, IAT and boninitic type) magmatic rocks from the upper part of the Neotethyan oceanic crust. Four samples from the amphibolitic rocks yielded 40Ar/39Ar isotopic ages, ranging from 87.04 ± .36 Ma to 84.66 ± .30 Ma. Comparison of geochemistry and geochronology for the amphibolitic rocks suggests that the alkaline amphibolite (seamount-type) cooled below 510 ± 25 °C at 87 Ma whereas the tholeiitic amphibolites at 85 Ma during intraoceanic thrusting/subduction. When all the evidence combined together, the intraoceanic subduction initiated in the vicinity of an off-axis plume or a plume-centered spreading ridge in the Inner Tauride Ocean at 87 Ma. During the later stage of the steady-state subduction, the E-MORB volcanics on the top of the down-going slab and the arc-type basalts (IAT/boninitic) detached from the leading edge of the overriding plate, entered the subduction zone after ~2 my and metamorphosed to amphibolite facies in the Inner Tauride Ocean. Duration of the intraoceanic detachment (~87 Ma) and ophiolite emplacement onto the Tauride-Anatolide Platform (Tav?anl? Zone), followed by subsequent HP/LT metamorphism (~82 Ma) spanned ~5 my in the western part of the Inner Tauride Ocean. 相似文献
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Merve Zeyrek Kadriye Ertekin Sibel Kacmaz Cemil Seyis Sedat Inan 《Geostandards and Geoanalytical Research》2010,34(1):67-77
A single-column suppressed ion chromatography technique was employed for the simultaneous determination of major and trace anions in sulfaterich groundwater samples. An analytical column, a self regenerating suppressor and sodium carbonate as the eluent were used to separate the anions. Method detection limits for the anions of interest were 10.4, 15.9, 36.8, 62, 60, 61 and 67 μg l−1 for F− , Cl− , NO2 − , Br− , NO3 − , PO4 3− and SO4 2− respectively. The precision of the method was tested at five different concentration levels for each anion reference sample to evaluate the effectiveness of the method for groundwater analysis. Recovery studies were performed between two successive months by adding reference samples to the geothermal groundwater and drinking water samples. Precision was also assessed as the relative standard deviation of both repeatability (within-day) and reproducibility (between-day and different concentrations) for groundwater samples. Standard deviation and RSD values of 220 groundwater samples acquired over 8 months were evaluated. The suppressed ion chromatography technique was found to be a suitable method for determining major anions in sulfate-rich geothermal water samples. 相似文献
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In this study, a beam-to-column connection in cold-formed steel structure has been examined using self-drilling screw. An experimental study is carried out for the full-scale specimens of the connection. The beam has different thickness to determine the structural behavior of the connection. The behavior of connections is represented by their moment–rotation curve. So, this study focuses on evaluating the moment–rotation curves and whose characteristic values. The aim of the work is also to provide failure mechanism for the connection whose fastener is self-drilling screws. The failures of the connected members and screws are observed in the knee joint configuration. This was performed through cantilever tests of full-scale beam-to-column joints. Experiment results were evaluated by comparing to the results of other experiments with different combination thickness. The experimental results showed that plastic and maximum deformation decreases while maximum moment and stiffness increases when the profile thickness of the beam increased. 相似文献
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Community structure of epiphytic algae on three different macrophytes at Acarlar floodplain forest （northern Turkey） 总被引：2，自引：2，他引：0
Hatice TUNCA Tugba ONGUN SEVINDIK Dilek Nur BAL Sevil ARABACI 《中国海洋湖沼学报》2014,32(4):845-857
The aim of this study was to determine the species composition, biodiversity and, relative abundance of epiphytic algae and their relationship with environmental variables on three different macrophytes( Nymphaea alba, Ceratophyllum demersum, Typha latifolia) at Acarlar Floodplain Forest(AFF). Epiphytic algae were gathered monthly by collecting aquatic plants between November 2011 and October 2012, except in winter when there were no plants. In this study, 67 taxa on N. alba, 66 taxa on C. demersum and 66 taxa on T. latifolia were identified as epiphytic algae. The mean value of species richness was 17, that of diversity was 1.5 and that of evenness was 0.54 for epiphytic algae on N. alba, 17, 1.1, and 0.39 on C. demersum, and 18, 1.64, and 0.56 on T. latifolia, respectively. Oscillatoria sp. and Komvophoron crassum(Vozzen) Anagnostidis and Komárek were the most abundant and consistent epiphytic algal species, occurring in high abundance on all macrophytes. Results show that species composition of epiphytic algae was different, but diversity values were similar on all the macrophytes. The hydrological pulse is one of the most important factors determining the physical and chemical environment of the epiphytic algal community. However, substrate type also affected the colonization by F. capucina, O. sancta, P. catenata, and L. truncicola more than the epiphytic algal seasonality. 相似文献
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Utkucu Murat Durmuş Hatice Nalbant Süleyman 《International Journal of Earth Sciences》2017,106(6):1841-1861
International Journal of Earth Sciences - Earthquake ruptures perturb stress within the surrounding crustal volume and as it is widely accepted now these stress perturbations strongly correlates... 相似文献