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21.
A good number of empirical formulae and methods dealing with the analysis of the effects of blast-induced ground vibrations have been developed. The most common approach suggested for estimating the attenuation of particle velocity on the ground is to scale the distance (scaled distance, SD). This approach makes it possible to estimate the peak particle velocity when the amount of explosive charge or the distance or both are altered.Many parameters known to have an influence on particle velocity have been used for particle velocity prediction equations. Some of these parameters are maximum charge per delay, the distance between the station and shot location, burden, inelastic attenuation factor and site factors. However, the impacts of the discontinuities existing on the benches where blasts are detonated on the propagation velocity of seismic waves have not been taken into consideration in these equations.This study aims to examine the impacts of the discontinuity frequency parameter derived through geological measurements carried out on the blasting benches or nearby in a quarry mine (Supren, Eskisehir) in Turkey on the propagation of blast-induced ground vibrations. Developed based on the geological observations carried out on the benches, the model was formed by adding discontinuity frequency parameter to the particle velocity prediction model suggested by Nicholls et al. [Nicholls HR, Johnson CF, Duvall WI. Blasting vibrations and their effects on structures. Bulletin no. 656. Washington, DC: US Bureau of Mines; 1971]. In order to research the effect of the discontinuity frequency in the bench on the blast-induced ground vibrations, the relationship between the recorded peak particle velocity, scaled distance and discontinuity frequency was statistically evaluated for the site. The established relationship and the results of the study are presented. 相似文献
22.
Hakan Sirin Miguel A. Mariño 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(4):551-565
The laboratory-scale ground water transport equation with nonequilibrium sorption reaction subjected to unsteady, nondivergence-free,
and nonstationary velocity fields is up-scaled to the field-scale by using the ensemble-averaged equations obtained from the
cumulant expansion ensemble-averaging method. It is found that existing ensemble-averaged equations obtained with the help
of the cumulant expansion method for the system of linear partial differential equations are not second-order exact. Although
the cumulant expansion methodology is designed for noncommuting operators, it is found that there are still commudativity
requirements that need to be satisfied by the functions and constants exist in the coefficient matrix of the system of ordinary/partial
differential equations. A reversibility requirement, which covers the commudativity requirements, is also proposed when applying
the cumulant expansion method to a system of partial differential equations/a partial differential equation. The significance
of the new velocity correction obtained in this study due to the applied second-order exact cumulant expansion is investigated
on a numerical example with a linear trend in the distribution coefficient. It is found that the effect of the new velocity
correction can be significant enough to affect the maximum concentration values and the plume center of mass in the case of
a trending distribution coefficient in a physically heterogeneous environment. 相似文献
23.
M. Selman Aydoan Hakan oban Mustafa Bozcu
mer Aknc 《Journal of Asian Earth Sciences》2008,33(3-4):155-176
The (late syn)- post-collisional magmatic activities of western and northwestern Anatolia are characterized by intrusion of a great number of granitoids. Amongst them, Baklan Granite, located in the southern part of the Muratdağı Region from the Menderes Massif (Banaz, Uşak), has peculiar chemical and isotopic characteristics. The Baklan rocks are made up by K-feldspar, plagioclase, quartz, biotite and hornblende, with accessory apatite, titanite and magnetite, and include mafic microgranular enclaves (MME). Chemically, the Baklan intrusion is of sub-alkaline character, belongs to the high-K, calc-alkaline series and displays features of I-type affinity. It is typically metaluminous to mildly peraluminous, and classified predominantly as granodiorite in composition. The spider and REE patterns show that the rocks are fractionated and have small negative Eu anomalies (Eu/Eu* = 0.62–0.86), with the depletion of Nb, Ti, P and, to a lesser extent, Ba and Sr. The pluton was dated by the K–Ar method on the whole-rock, yielded ages between 17.8 ± 0.7 and 19.4 ± 0.9 Ma (Early Miocene). The intrusion possesses primitive low initial 87Sr/86Sr ratios (0.70331–0.70452) and negative εNd(t) values (−5.0 to −5.6). The chemical contrast between evolved Baklan rocks (SiO2, 62–71 wt.%; Cr, 7–27 ppm; Ni, 5–11 ppm; Mg#, 45–51) and more primitive clinopyroxene-bearing monzonitic enclaves (SiO2, 54–59 wt.%; Cr, 20–310 ppm; Ni, 10–70 ppm; Mg#, 50–61) signifies that there is no co-genetic link between host granite and enclaves. The chemical and isotopic characteristics of the Baklan intrusion argue for an important role of a juvenile component, such as underplated mantle-derived basalt, in the generation of the granitoids. Crustal contamination has not contributed significantly to their origin. However, with respect to those of the Baklan intrusion, the generation of the (late syn)- post-collisional intrusions with higher Nd(t) values from the western Anatolia require a much higher amount of juvenil component in their source domains. 相似文献
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26.
Sloshing in a three-dimensional rectangular tank: Numerical simulation and experimental validation 总被引:1,自引:0,他引:1
Pressure variations and three-dimensional effects on liquid sloshing loads in a moving partially filled rectangular tank have been carried out numerically and experimentally. A numerical algorithm based on the volume of fluid (VOF) technique is used to study the non-linear behavior and damping characteristics of liquid sloshing. A moving coordinate system is used to include the non-linearity and avoid the complex boundary conditions of moving walls. The numerical model solves the complete Navier–Stokes equations in primitive variables by using of the finite difference approximations. In order to mitigate a series of discrete impacts, the signal computed is averaged over several time steps. In order to assess the accuracy of the method used, computations are compared with the experimental results. Several configurations of both baffled and unbaffled tanks are studied. Comparisons show good agreement for both impact and non- impact type slosh loads in the cases investigated. 相似文献
27.
Source apportionment of trace metals in surface waters of a polluted stream using multivariate statistical analyses 总被引:16,自引:0,他引:16
Surface water samples were collected from ten previously selected sites of the polluted Dil Deresi stream, during two field surveys, December 2001 and April 2002. All samples were analyzed using ICP-AES, and the concentrations of trace metals (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Pb, Sn and Zn) were determined. The results were compared with national and international water quality guidelines, as well as literature values reported for similar rivers. Factor analysis (FA) and a factor analysis-multiple regression (FA-MR) model were used for source apportionment and estimation of contributions from identified sources to the concentration of each parameter. By a varimax rotated factor analysis, four source types were identified as the paint industry; sewage, crustal and road traffic runoff for trace metals, explaining about 83% of the total variance. FA-MR results showed that predicted concentrations were calculated with uncertainties lower than 15%. 相似文献
28.
Istanbul Earthquake Rapid Response and the Early Warning System 总被引:13,自引:0,他引:13
M. Erdik Y. Fahjan O. Ozel H. Alcik A. Mert M. Gul 《Bulletin of Earthquake Engineering》2003,1(1):157-163
One hundred strong motion accelerometers have been placed in populated areas of Istanbul, within an area of approximately
50×30 km, to constitute a network that will enable rapid shake map and damage assessment after a damaging earthquake. After
triggered by an earthquake, each station will process the streaming strong motion to yield the spectral accelerations at specific
periods and will send these parameters in the form of SMS messages to the main data center through available GSM network services.
A shake map and damage distribution will be automatically generated. The shake and damage maps will be available on the Internet
and will also be pushed to several end users. For earthquake early warning information ten strong motion stations were located
as close as possible to the Marmara Fault. The continuous on-line data from these stations will be used to provide near-real
time warning for emerging potentially disastrous earthquakes.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
29.
Marine Geophysical Research - Predictive deconvolution is an effective way to suppress multiple reflections, especially short path multiples, in seismic data. However, the effectiveness of the... 相似文献
30.
Seasonal variations and distributions of dissolved carbohydrate concentrations at the İzmir Bay were investigated with salinity, chlorophyll a (Chl a), and dissolved organic carbon (DOC) levels to understand their relationships. Samples were collected from surface, subsurface and bottom depths at seven stations. DOC concentrations ranged from 32.2 to 244.2 μmol/L, and in general, DOC levels increased from winter to summer, then slightly decreased in autumn. Monosaccharide (MCHO), polysaccharide (PCHO) and total dissolved carbohydrate (TDCHO) levels were found between 0.7-8.3, 0.7-19.5, and 2.6-24.6 μmol/L. DOC, MCHO, PCHO and TDCHO levels were found higher in middle-inner bays, under the influence of anthropogenic inputs, compared to outer bay. Seasonal changes of MCHO/DOC, PCHO/DOC and TDCHO/DOC ratios were statistically significant (p<0.05) and the ratios showed decrease trends from winter to summer-autumn seasons. Distributions of TDCHO/DOC ratios at wide ranges (2.5%-42.3%) indicated the presence of newly forming and degrading fractions of DOM. According to results of factor analysis, Chl a, MCHO and TDCHO were explained in the same factor groups. In conclusion, the results showed that dissolved carbohydrate levels in the İzmir Bay might be influenced by biological processes and terrestrial/anthropogenic inputs. 相似文献