排序方式： 共有9条查询结果，搜索用时 31 毫秒
1
1.
Geo-Characterization at selected accelerometric stations in Crete (Greece) and comparison of earthquake data recordings with EC8 elastic spectra 总被引：1，自引：0，他引：1
A. Savvaidis B. Margaris N. Theodoulidis V. Lekidis Ch. Karakostas C. Loupasakis D. Rozos P. Soupios M. -D. Mangriotis U. Dikmen Par. Tsangaratos E. Kokinou A. Vafidis Th. Rondoyanni I. Kalogeras S. Koutrakis A. Sarris N. Papadopoulos 《Central European Journal of Geosciences》2014,6(1):88-103
To estimate the seismic response according to Eurocode (EC8) and almost all other national codes, site conditions have to be properly characterized so that soil amplification and the corresponding peak ground motion can be calculated. In this work, different geophysical and geotechnical methods are combined in order to define the detailed ground conditions in selected sites of the Hellenic Accelerometric Network (HAN) in Crete. For this purpose, the geological information of the sites and shear wave velocity, calculated from surface wave measurements, is used. Additionally, ground acceleration data recorded through HAN have been utilized from intermediate depth earthquakes in the broader area of South Aegean Sea. Using the recorded ground motion data and the procedure defined in EC8, the corresponding elastic response spectrum is calculated for the selected sites. The resulting information is compared to the values defined in the corresponding EC8 spectrum for the seismic zone that includes the island of Crete. The comparison shows that accurate definition of ground type through geological, geotechnical and geophysical investigations is important. However, our current comparison focuses on the distribution of values rather than the absolute values of EC8-prescribed spectra, and the results should be considered in this context. 相似文献
2.
Sedef Cakir Mikdat Kadioglu Nihat Cubukcu 《Theoretical and Applied Climatology》2013,111(3-4):703-711
The ensemble method has long been used to reduce the errors that are caused by initial conditions and/or parameterizations of models in forecasting problems. In this study, neural network (NN) simulations are applied to ensemble weather forecasting. Temperature forecasts averaged over 2 weeks from four different forecasts are used to develop the NN model. Additionally, an ensemble mean of bias-corrected data is used as the control experiment. Overall, ensemble forecasts weighted by NN with feed forward backpropagation algorithm gave better root mean square error, mean absolute error, and same sign percent skills compared to those of the control experiment in most stations and produced more accurate weather forecasts. 相似文献
3.
4.
The effectiveness of coagulation (at pH values of 6, 7.5, and 9), flocculation (at pH 9), and coagulation plus flocculation (at pH 9) on turbidity removal from natural stone (travertine) processing wastewaters (NSPW) were examined by applying classical sedimentation tests. FeCl3·6 H2O, AlCl3, and Al2(SO4)3·16 H2O were used as coagulants and a polyacrylamide based anionic polymer was used as the flocculant. In this way, it was found that the coagulation method alone was not sufficient to purify NSPW, whereas flocculation and coagulation plus flocculation methods provided superior purification. Among the coagulants used, AlCl3 gave the best result in terms of turbidity removal by coagulation from NSPW at pH 6 and 9, whereas the turbidity removal performances of the three coagulants were almost identical at pH 7.5. In addition, relatively low pH (i. e., pH 6) improved the purification performance of all coagulants. During coagulation of NSPW at pH 6, a charge neutralization mechanism played a decisive role in turbidity removal. However, in neutral (pH 7.5) and slightly basic (pH 9) media, a sweep coagulation mechanism was predominant. For flocculation of NSPW, the basic mechanism comprised of polymer bridging. 相似文献
5.
Arif Mert Eker Mehmet Dikmen Selim Cambazoğlu Şebnem H.B. Düzgün 《International journal of geographical information science》2013,27(1):132-158
The purpose of this study was to investigate the capabilities of different landslide susceptibility methods by comparing their results statistically and spatially to select the best method that portrays the susceptibility zones for the Ulus district of the Bart?n province (northern Turkey). Susceptibility maps based on spatial regression (SR), linear discriminant analysis (LDA), quadratic discriminant analysis (QDA), logistic regression (LR) method, and artificial neural network method (ANN) were generated, and the effect of each geomorphological parameter was determined. The landslide inventory map digitized from previous studies was used as a base map for landslide occurrence. All of the analyses were implemented with respect to landslides classified as rotational, active, and deeper than 5 m. Three different sets of data were used to produce nine explanatory variables (layers). The study area was divided into grids of 90 m × 90 m, and the ‘seed cell’ technique was applied to obtain statistically balanced population distribution over landslide inventory area. The constructed dataset was divided into two datasets as training and test. The initial assessment consisted of multicollinearity of explanatory variables. Empirical information entropy analysis was implemented to quantify the spatial distribution of the outcomes of these methods. Results of the analyses were validated by using success rate curve (SRC) and prediction rate curve (PRC) methods. Additionally, statistical and spatial comparisons of the results were performed to determine the most suitable susceptibility zonation method in this large-scale study area. In accordance with all these comparisons, it is concluded that ANN was the best method to represent landslide susceptibility throughout the study area with an acceptable processing time. 相似文献
6.
Effects of Rock Properties on Specific Cutting Energy in Linear Cutting of Sandstones by Picks 总被引：4，自引：2，他引：4
Summary. Specific cutting energy (SE) has been widely used to assess the rock cuttability for mechanical excavation purposes. Some
prediction models were developed for SE through correlating rock properties with SE values. However, some of the textural
and compositional rock parameters i.e. texture coefficient and feldspar, mafic, and felsic mineral contents were not considered.
The present study is to investigate the effects of previously ignored rock parameters along with engineering rock properties
on SE. Mineralogical and petrographic analyses, rock mechanics, and linear rock cutting tests were performed on sandstone
samples taken from sites around Ankara, Turkey. Relationships between SE and rock properties were evaluated using bivariate
correlation and linear regression analyses.
The tests and subsequent analyses revealed that the texture coefficient and feldspar content of sandstones affected rock cuttability,
evidenced by significant correlations between these parameters and SE at a 90% confidence level. Felsic and mafic mineral
contents of sandstones did not exhibit any statistically significant correlation against SE. Cementation coefficient, effective
porosity, and pore volume had good correlations against SE. Poisson’s ratio, Brazilian tensile strength, Shore scleroscope
hardness, Schmidt hammer hardness, dry density, and point load strength index showed very strong linear correlations against
SE at confidence levels of 95% and above, all of which were also found suitable to be used in predicting SE individually,
depending on the results of regression analysis, ANOVA, Student’s t-tests, and R2 values. Poisson’s ratio exhibited the highest correlation with SE and seemed to be the most reliable SE prediction tool in
sandstones. 相似文献
7.
Bojana Petrovic Stefano Parolai Giovanna Pianese S. Umit Dikmen Bolot Moldobekov Sagynbek Orunbaev Roberto Paolucci 《Bulletin of Earthquake Engineering》2018,16(2):613-641
In this study, the joint deconvolution is applied to recordings of three test cases located in the cities of Bishkek, Kyrgyzstan, Istanbul, Turkey, and Mexico City, Mexico. Each test case consists of a building equipped with sensors and a nearby borehole installation in order to investigate different cases of coupling (impedance contrasts) between the building and the soil by analyzing the wave propagation through the building-soil-layers, and hence resolving the soil–structure-interactions. The three installations considering different dynamic characteristics of buildings and soil, and thus, different building-soil couplings, are investigated. The seismic input (i.e., the part of the wave field containing only the up-going waves after removing all down-going waves) and the part of the wave field that is associated with the waves radiated back from the building are separated by using the constrained deconvolution. The energy being radiated back from the building to the soil has been estimated for the three test cases. The values obtained show that even at great depths (and therefore distances), the amount of wave field radiated back by the building to the soil is significant (e.g., for the Bishkek case, at 145 m depth, 10% of the estimated real input energy is expected to be emitted back from the building; for Istanbul at 50 m depth, the value is also 10–15% of the estimated real input energy while for Mexico City at 45 m depth, it is 25–65% of the estimated real input energy). Such results confirm the active role of buildings in shaping the wave field. 相似文献
8.
The Geoelectrical Structure of Northwestern Anatolia,Turkey 总被引：1，自引：0，他引：1
E. U. Ulugergerli G. Seyitoğlu A. T. Başokur C. Kaya U. Dikmen M. E. Candansayar 《Pure and Applied Geophysics》2007,164(5):999-1026
The magnetotelluric method has been employed to generate a geoelectrical model that will reveal the rich geological pattern and dynamic character of western and northwestern Anatolia, Turkey. Magnetotelluric data were collected from 53 sites along a profile of 290 km from the Dardanelles to the Ala?ehir Graben. Magnetotelluric data were in the range of 0.00055 Hz to 320 Hz. The models were obtained through 2-D joint inversion of transverse electric and transverse magnetic modes. Lateral changes in geoelectrical models are verified by using gravity and magnetic data. In addition, some of the seismological data presented here agree with proposed models that suggest a brittle-ductile structure boundary at a depth of 20 km. Generally speaking, a regional extensional regime caused reduction in the thickness of the crust and consequent uplift towards the south. The constructed model delineates the western part of the North Anatolian Fault Zone along the Biga Peninsula. The current patterns of volcanic activity on the Biga Peninsula and at Kula are related to conductive spots presented in the models. The border of the Gördes Basin, located between the Izmir - Ankara suture zone and the Menderes Massif, is also well delineated. The North Anatolian Fault Zone presents a pattern in which density and susceptibility anomalies attain relatively high values. Fillings covering most of the surface have lower density and susceptibility values than those of underlying structures. 相似文献
9.
1