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71.
The relationship of heat flow to age of the basement rocks has been studied for USA and Canada, Australia and India. In areas of sedimentary basins the ages of the cores obtained from the metamorphic or igneous basement were used for such correlation. It is found that heat flow values for all continents studied show a definite correlation with age the relatively high heat flow being associated with younger basements. Such correlation when fully established will enable us to correlate heat flow values with geology and ages of tectonic events which have occurred in the earth’s crust. 相似文献
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73.
A neural network approach for attenuation relationships: An application using strong ground motion data from Turkey 总被引:1,自引:0,他引:1
This paper presents an application of neural network approach for the prediction of peak ground acceleration (PGA) using the strong motion data from Turkey, as a soft computing technique to remove uncertainties in attenuation equations. A training algorithm based on the Fletcher–Reeves conjugate gradient back-propagation was developed and employed for three sample sets of strong ground motion. The input variables in the constructed artificial neural network (ANN) model were the magnitude, the source-to-site distance and the site conditions, and the output was the PGA. The generalization capability of ANN algorithms was tested with the same training data. To demonstrate the authenticity of this approach, the network predictions were compared with the ones from regressions for the corresponding attenuation equations. The results indicated that the fitting between the predicted PGA values by the networks and the observed ones yielded high correlation coefficients (R2). In addition, comparisons of the correlations by the ANN and the regression method showed that the ANN approach performed better than the regression. Even though the developed ANN models suffered from optimal configuration about the generalization capability, they can be conservatively used to well understand the influence of input parameters for the PGA predictions. 相似文献
74.
M.S. Hamza 《Geochimica et cosmochimica acta》1974,38(5):669-681
The surface effect on the isotopic fractionation between CO2 and calcite, dolomite and witherite has been studied through gas-solid exchange experiments. Oxygen isotope fractionation between surface calcite and CO2 was found to be higher by 5–6%. than the fractionation between bulk calcite and CO2.Similar studies were made using dolomite and witherite. The dolomite-calcite and witheritecalcite fractionation evaluated through the surface exchange with CO2 were found to be close to values determined by other workers under controlled conditions in the laboratory. 相似文献
75.
Seismic hazard studies were conducted for Gaziantep city in the South Anatolia of Turkey. For this purpose, a new attenuation
relationship was developed using the data of Zaré and Bard and accelerations were predicted employing this new equation. Deterministic
approach, total probability theorem and GIS methodology were all together utilized for the seismic assessments. Seismic hazard
maps with 0.25° grid intervals considering the site conditions were produced by the GIS technique. The results indicated that
the acceleration values by the GIS hazard modelings were matched with the ones from the deterministic approach, however, they
were underestimated comparing with the total probability theorem. In addition, the GIS based seismic hazard maps showed that
the current seismic map of Turkey fairly yields conservative acceleration values for the Gaziantep region. Therefore, the
constructed GIS hazard models are offered as a base map for a further modification of the current seismic hazard map. 相似文献
76.
V. M. Hamza R. R. Cardoso C. F. Ponte Neto 《International Journal of Earth Sciences》2008,97(2):233-239
Pollack and Chapman, hereafter referred to as P&C, argue that: (1) errors arising from lack of quality control in the IHFC
database are not important and not properly documented, (2) resolution of spatial patterns in global heat flux distribution
should not be represented by spherical harmonics and (3) heat flow in young oceanic crust and global heat loss are better
represented by a contested 1-D cooling model than by the data. We disagree and provide additional information that may help
clear up such misunderstandings. We also mention briefly the results of a new improved thermal model of the lithosphere that
satisfactorily reproduces the main features identified in observational data sets of heat flow and ocean floor bathymetry.
Thus, there is no reason to invoke the ad hoc hypothesis of large-scale hydrothermal circulation in the ocean crust. 相似文献
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78.
We have investigated the fate of Staphylococcus aureus by starving the cells and maintaining them in natural seawater at 22 and 4 °C. At 22 °C, cells developed a long-term survival state where about 0.037% of the initial population remained culturable over more than 7 months, whereas at 4 °C, bacteria lost culturability and transiently entered into the viable but non-culturable state (VBNC). However, after 22 days of entry into the VBNC state, the number of viable cells detected via the direct viable count method decreased significantly. We show here that mutational inactivation of catalase (KatA) or superoxide dismutase (SodA) rendered strains hypersensitive to seawater stress at 4 °C and consequently, part of the seawater lethality on S. aureus at low temperature is mediated by reactive oxygen species (ROS) during microcosm-survival process. Shifting the temperature from 4 to 22 °C of totally non-culturable wild-type cells induced a partial recovery of the population. However, deficiencies in catalase or superoxide dismutase prevent resuscitation ability. 相似文献
79.
The paper is devoted to the study of uncertainties when studying buildings under seismic loading. These uncertainties are
related to the simplifications used when constructing the model (model uncertainties) and to the numerical data needed at
the computation stage (data uncertainties). It has been shown in previous papers that nonparametric models are able, in the
case of linear dynamics, to deal simultaneously with these two kinds of uncertainties. The paper presents an extension of
this kind of model by taking into account a “mixed” approach for concrete frame structures, which uses a nonparametric model
for the part of the structure which behaves linearly and a parametric approach for the parts of the structure (plastic hinges)
which behave non-linearly. A numerical application is presented in the case of a residential building. 相似文献
80.
S. M. Hamza Amimul Ahsan M. A. Imteaz T. A. Mohammad A. H. Ghazali A. R. M. Shariff 《Arabian Journal of Geosciences》2017,10(7):168
Safeguarding groundwater from pollution is largely a global political decision. These decisions are basically supported by DRASTIC (D=Depth to water, R=Recharge, A=Aquifer media, S=Soil media, T=Topography, I=Impact of vadose zone, C=Hydraulic conductivity) analysis. Furthermore, water quality index (WQI) is an effective tool for groundwater quality evaluation and management. This study identifies the relationship between these two indices [i.e., pollution vulnerability index (PVI) and WQI]. The DRASTIC index of the study area was found to be from 60.4 to 178 characterized by very low, low, medium high, and very high vulnerability constituting of 12.88, 24.38, 34.11, 21.99, and 6.63% of the study area, respectively. In addition, the WQI of the area according to the analyzed parameters is between 10.19 and 55.63. It was established that a good correlation (61%) was found to exist between the two indices; which may be an indication that most pollutants present in the groundwater are likely due to anthropogenic activities on the land surface. 相似文献