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111.
The subsurface shear-wave velocity (Vs) is considered to be a key parameter for site characterization and assessment of earthquake
hazard because of its great influence on local ground-motion amplification. Array microtremor measurements are widely used
for the estimation of shear-wave velocities. Compared to other methods such as frequency-wavenumber (f-k) methods, the spatial
autocorrelation (SPAC) method requires fewer sensors and thus is relatively easier to implement and gives robust estimations
of shear-wave velocity profiles for depths down to a few hundred meters. The quantity derived from observed data is the SPAC
coefficient, which is a function of correlation distance, frequency and phase velocity. Generally, estimation of Vs profiles
is a two stage process: Estimation of the dispersion data from the SPAC coefficients and inversion of the dispersion data
for shear-wave velocity structure. In this study, instead of inverting dispersion curves, a more practical approach is used;
that is, observed SPAC coefficients are directly inverted for the S-wave velocities. A synthetic case and a field data application
are presented to test the potential of the inversion algorithm. We obtain an iterative damped least-squares solution with
differential smoothing. The differential smoothing approach constrains the change in shear-wave velocities of the adjacent
layers and thus stabilizes the inversion. 相似文献
112.
In this study, the decolorization, dearomatization, and mineralization efficiencies of different advanced oxidation processes (AOPs; namely O3, O3/Fe(II), O3/Fe(II)/UVA, and O3/TiO2/UVA) were investigated for the azo dye C.I. Reactive Red 194 (RR194). The effects of pH (3–11), amount of TiO2 (0.05–1 g/L), and concentration of Fe(II) (0.1–1.6 mM) were investigated for the applied methods. The decolorization and mineralization efficiencies of the photocatalytic ozonation system (O3/TiO2/UVA) were increased by decreasing the pH of the dye solution in contrast to the ozonation system (O3). Decolorization of RR194 was increased in the photocatalytic ozonation system with an increasing amount of catalyst however, a decreasing was occurred for the homogeneous catalytic system (O3/Fe(II)) when increasing the concentration of catalyst. The decolorization efficiency of the homogeneous catalytic system (O3/Fe(II)) was enhanced when combined with UVA light. In our study, the most efficient method for dearomatization and mineralization was the O3/TiO2/UVA among the applied AOPs. 相似文献
113.
An on‐line solid phase extraction method for the preconcentration and determination of Cu(II) by flame atomic absorption spectrometry has been described. The procedure is based on the retention of Cu(II) ions at pH 6.0 on a minicolumn packed with Amberlite XAD‐1180 resin impregnated with chrome azurol S. After preconcentration, Cu(II) ions adsorbed on the impregnated resin were eluted by 1 mol L?1 HNO3 solution. Several parameters, such as pH, type of eluent, flow rates of sample and eluent solutions, amount of resin were evaluated. At optimized conditions, for 3.5 min of preconcentration time, the system achieved a detection limit of 1.0 µg L?1, and a relative standard deviation of 1.2% at 0.2 µg mL?1 copper. An enrichment factor of 56‐fold was obtained with respect to the copper determination. The proposed method was successfully validated by the analysis of standard reference material (TMDA 54.4 lake water) and recovery studies. The method was applied to the preconcentration of Cu(II) in natural water samples. 相似文献
114.
The teleseismic P receiver functions are customarily inverted to attain the seismic velocities beneath a seismic station. Surface wave dispersion
data are often added to reduce the effect of the non-uniqueness. The combination of P receiver function and surface wave works well in resolving the structures in the crust and uppermost mantle, but is less
effective in characterizing greater (lithosphere and asthenosphere) depths due to the interference from crustal multiples.
A solution to this problem is jointly to model teleseismic S receiver functions with surface wave and P receiver functions. This study adopts a fast, one-dimensional (1-D) inversion scheme. To avoid the effect of multidimensional
structures away from the seismic station, we eliminate multiples that reverberate between the surface and interfaces below
a restriction depth (RD), as well as S-to-P conversions below an inversion depth (ID). P-to-S conversions off the interfaces above the half-space and S-to-P conversions above the ID and multiples above the RD are properly modelled. This approach favours ray paths travelling close
to stations and is, therefore, more suitable for 1-D inversions. We perform numerical experiments with and without noise and
highlight the advantages of a joint receiver function and surface wave analysis. 相似文献
115.
Investigation of water quality on Gökçekaya dam lake using multivariate statistical analysis,in Eskişehir,Turkey 总被引:1,自引:0,他引:1
Gökçekaya Dam is one of the dams located on the Sakarya River (Eski?ehir) in Turkey and is approximately 38 years old. No study regarding to the water quality of the dam lake has been hitherto made. This study aimed at determining the seasonal variations with physical, chemical, and biological parameters of the water quality of the dam lake. Depth-wise water samples were taken from five selected stations, in seasonal periods during 2005–2008, and anlayzed. The quality of water was classified in accordance with the results and taking into consideration many parameters. At the same time, number and type diversities of dissolved heavy metals and algae population were analyzed. Using principal component analysis (PCA) and classification analysis (CA) methods, differences between these parameters and samples from stations have been determined . The analysis showed that Gökçekaya dam lake, formerly an oligotrophic lake, has become a mesotrophic lake. And according to the results thereof the Lake has mezotrophic characteristics due to the sudden changes (including household waste water inflow and opening the Sar?yar dam lake shutters) in certain periods and in some stations. Hierarchical clustering analysis, revealed no significant difference between the measured parameters. And according to the Water Pollution Control Regulations in Turkey (WPCR) Gökçekaya dam lake is in the first class quality in terms of anions, cations, heavy metals, temperature, and pH values. However, the is of first class quality presence of nitrite reduces the water quality in the lake and causes this lake to be classified in the fourth class quality. 相似文献
116.
Semir Över Aydın Büyüksaraç Özcan Bekta Ahmet Filazi 《Environmental Earth Sciences》2011,62(2):313-326
Antakya city is at risk because of strong earthquakes occurring in the area, and different soil conditions that can produce variation of the ground motion amplification. Microzonation of cities provides a basis for site-specific hazard analysis in urban settlements. In particular, seismic microzonation can be provided by means of detailed seismic assessment of the area, including earthquake recordings and geological studies. In this paper, we propose a preliminary microzonation map for the city of Antakya, based on the variation of the dominant periods and shear velocities of the sediments covering the area. The periods are retrieved from microtremor measurements conducted at 69 sites, using the horizontal-to-vertical spectral ratio technique. The results of microtremor analysis were compared with data obtained from refraction microtremor (ReMi) measurements at four profiles crossing the studied area. According to the classification of dominant periods, Antakya city can be divided into five zones, probably prone to different levels of seismic hazard. The shorter natural periods are in inner Antakya and both the sides of Asi River (i.e., northern and southern parts). The eastern and western parts of Antakya have maximum dominant periods. The V s 30 values were calculated by using the ReMi method along the profiles. Antakya city has V s 30 values in the range of category C of the national earthquake hazard reduction programme site classification. 相似文献
117.
Lake E?irdir is located in the Lakes District in southwestern Turkey and it is the second largest freshwater resource lake. Evaporation is an important parameter in hydrological and meteorological practical studies. This study has three objectives: (1) to develop models for the estimation of daily evaporation using measured data from the automated GroWeather meteorological station located near Lake E?irdir; (2) to compare the evaporation models with the classical Penman approach; (3) to evaluate the potential of each model. The comparisons are based on daily and monthly available data from 2001 and 2002. The evaporation estimation models (EEMs) developed in this paper have lower mean absolute errors and higher coefficient of determination R2 values than the Penman method. In order to evaluate the potential of the EEMs, daily evaporation values are calculated by the Priestley–Taylor, Brutsaert–Stricker, de Bruin, Makkink and Hamon methods. The EEMs are statistically indistinguishable from the classical methods on the basis of the parameters of mean, standard deviation, etc. In the evaluation of daily and monthly values, the relative error percentage for daily evaporation has lower values than for monthly evaporation. It can be seen that the EEMs help in calculating daily evaporation rather than monthly. Final evaluation and comparison indicate that there is a good agreement between the results of EEMs and the Penman approach than with the classical methods. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
118.
Journal of Seismology - By using P and S wave receiver functions and P and S wave travel time residuals, we have found velocity models for 16 seismograph stations in Eastern Anatolia. Our study is... 相似文献
119.
Ganju Eshan Kılıç Mustafa Prezzi Monica Salgado Rodrigo Parab Niranjan Chen Wayne 《Acta Geotechnica》2021,16(11):3489-3516
Acta Geotechnica - This paper presents the results and analyses of uniaxial compression experiments performed on three silica sands. The sands have comparable particle-size distributions, but their... 相似文献
120.