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1.
A discussion of the effects of soil-structure interaction on the dynamic response of linear structures which respond as single-degree-of-freedom systems in their fixed-base condition is presented. The structures are presumed to be supported at the surface of a homogeneous, elastic halfspace and to be excited at the base. The free-field ground motions investigated include a harmonic motion, a relatively simple pulse-type excitation and an actual earthquake record. Comprehensive response spectra are presented for a range of the parameters defining the problem, and the results are used to assess the accuracy of a simple, approximate method of analysis in which the system is represented by a viscously damped, simple oscillator. Special attention is given to defining the conditions under which the interaction effect is of sufficient importance to warrant consideration in design. The method of analysis used to obtain the numerical data reported herein is reviewed only briefly, the emphasis of the paper being on the interpretation of the results. 相似文献
2.
A. Filippidis A. Georgakopoulos A. Kassoli-Fournaraki P. Misaelides P. Yiakkoupis J. Broussoulis 《International Journal of Coal Geology》1996,29(4):219-234
Drill core samples of three lignite seams from the central part of the Drama lignite deposit and their corresponding 1000°C ash samples were analyzed for their trace element contents by Instrumental Neutron Activation (INAA) and Inductively Coupled Plasma (ICP) analyses. Compared to crustal abundances, the lignite samples are enriched in As, Br, Mo and Sb, while Ba, Co, Cr, Cs, Eu, Hf, La, Lu, Rb, Sc, Sm, Tb, Yb, Zn, Zr and Au are depleted. While Br is negatively correlated with the ash content of the lignite samples, Ce, Co, Cr, La, Sc, Sm and Yb are positively correlated. Elements from the sorrounding rocks and mineralizations of the Drama Basin have influenced the inorganic constituents of the lignite. 相似文献
3.
Factors affecting the distribution of potentially toxic elements in surface soils around an industrialized area of northwestern Greece 总被引：2，自引：0，他引：2
Alexandra Petrotou Konstantinos Skordas Georgios Papastergios Anestis Filippidis 《Environmental Earth Sciences》2012,65(3):823-833
In order to investigate the factors influencing the distribution of 32 potentially toxic elements in the Ptolemais–Kozani
basin, northwestern Greece, 38 soil samples were collected and analyzed. Concentrations of Al, Ca, Fe, K, Mg, Mn, Na, P, Ti,
Ba, Co, Cr, Cu, La, Li, Ni, Pb, Sc, Sr, V, Y, and Zn were determined by ICP-AES and concentrations of As, Bi, Cd, Cs, Mo,
Rb, Sb, Th, Tl, and U by ICP-MS. Bivariate analysis, principal component analysis, and geostatistical analysis were employed
to investigate the factors influencing the distribution of the elements determined in the study area. The results indicate
that the distribution of the majority of elements determined, especially for Cr, Ni, and associated elements, is greatly influenced
by the geology and geomorphology of the study area. Principal component analysis has yielded four factors that explain over
77% of the total variance in the data. These factors are as follows: lithophilic elements that are associated with Al silicates
minerals of K (factor I: 29.4%), ultramafic rocks (factor II: 20.5%), elements that are coprecipitated with Fe and Mn oxides
(factor III: 18.0%), and anthropogenic activities (factor IV: 9.3%). The anthropogenic activities that influence the distribution
of several potentially toxic elements (i.e., Cd, Cu, Pb, Zn) are agricultural practices and the deposition of fly ash in the
vicinity of the local power stations. 相似文献
4.
Today Greece produces and exports raw bauxite and alumina, concentrates of galena and sphalerite and ferronickel. The indicated reserves of bauxite, located in the Mt Helikon-Mt Parnassus-Mt Giona-Mt Iti zone, are estimated at approximately 100 mt and those of aluminum 2.5 mt. The probable and indicated reserves of lead and zinc from Chalkidiki are approximately 3.125 mt. The total production of concentrates of galena and sphalerite is approximately 220,000 tpa. The proven reserves of nickel are approximately 1.392 mt and the production of ferronickel is approximately 18,500 tpa. Production of copper, silver and gold is pending in 2015. The probable and indicated reserves of copper from Skouries Chalkidiki are approximately 1.943 mt. In the Prefecture Units of Chalkidiki and Evros the probable and indicated reserves of gold are approximately 19.37 million ounces and those of silver 131.6 million ounces. Chromium, manganese and molybdenum present good prospects of exploitation. Calculated at current prices, the total gross value of the probable and indicated reserves of the metallic minerals of Greece is ?79.4 billion. 相似文献
5.
Anestis Filippidis Georgios Papastergios Nikolaos Kantiranis Kleopas Michailidis Athanasios Chatzikirkou Kostas Katirtzoglou 《Chemie der Erde / Geochemistry》2012,72(1):71-76
The possibility of using the species Silene compacta Fischer (Caryophyllaceae) as a plant indicator for Zn, Fe and Cu is discussed in this paper. Rock and plant samples were collected from an area near Essimi, north-eastern Greece, which is known for its Cu–Pb–Zn mineralization and analyzed for their content in 14 elements (Fe, Mn, Ag, As, Cd, Co, Cu, Mo, Ni, Pb, Sb, Sn, Zn and V). The data illustrate positive linear correlation between the concentrations of Zn, Fe and Cu in plant ash and rock samples. In particular, these correlations are 0.99 for Zn, 0.97 for Fe and 0.97 for Cu and are significant at the 99.9% confidence level. Therefore, S. compacta could be used as a plant indicator for Zn, Fe and Cu mineralization. 相似文献
6.
Anestis J. Romaides Christopher Jekeli Donald H. Eckhardt Charles L. Taylor 《Journal of Geodesy》1991,65(4):230-242
An experiment was conducted in 1987 in search for a possible non-Newtonian component to gravity. The test compared accurately measured gravity values on a 600 m tower with upward continued surface gravity. The results indicated a dominant attractive non-Newtonian force that asymptotically approached -540 µGal at the top of the tower. An exhaustive search of possible error sources led to the discovery that our surface data did not accurately represent some of the local topographic features. The surface survey was supplemented by gravity data to remove some of the biases that were caused by the misrepresentation. In addition, a rigorous terrain correction was applied to the surface data resulting in terrain-corrected Bouguer anomalies. These anomalies were then upward continued using two independent techniques. The terrain effect was added back to the predicted values at altitude. With this procedure almost the entire non-Newtonian effect was explained. Currently we find no conclusive evidence for a non-Newtonian force over the range of several hundred meters. 相似文献
7.
A recently proposed procedure for interrelating the steady-state and transient responses of multi-degree-of-freedom, classically damped linear systems is extended to non-classically damped systems. The extension is formulated for baseexcited systems, and it is illustrated by simple examples. 相似文献
8.
A. Filippidis A. Georgakopoulos A. Kassoli-Fournaraki 《International Journal of Coal Geology》1996,30(4):303-314
Two samples of Pliocene lignites from the Ptolemais basin of Greece, one from the upper and one from the lower lignite seams, were heated and dried in air at 50°C intervals from 50 to 1200°C. The two lignite samples initially contained the same minerals, namely calcite, dolomite, quartz, kaolinite, illite, pyrite and gypsum, but in different proportions. The lignite sample from the upper lignite seam is rich in Fe2O3, CaO and SO3, while that from the lower lignite seam is rich in SiO2 and Al2O3.Hematite, periclase, melilites, calcium ferrite and brownmillerite are constituents of the 1200°C lignite ash from both samples. The heating conditions and the chemistry of the samples lowered the formation temperatures of brownmillerite, which appeared in both samples at 950°C. In the Fe2O3, CaO- and SO3-rich sample, magnesioferrite is present from 850 to 1100°C and hematite appears at 300°C. In the SiO2- and Al2O3-rich sample, magnesioferrite was not detected at any temperature and hematite appeared at 600°C.Anhydrite, which normally decomposes in air at 1638°C, is the main constituent at 1150°C, on heating the lignite sample that was rich in Fe2O3, CaO and SO3. Anhydrite diminishes at 1200°C. In the SiO2- and Al2O3-rich lignite sample, anhydrite is main constituent at 1100°C, but diminishes considerably at 1150°C and decomposes at 1200°C. 相似文献
9.
After reviewing briefly a recently proposed procedure for evaluating the dynamic transient response of a classically damped linear system from its corresponding steady-state response, a modified procedure is presented which also appears to be highly efficient for non-classically damped systems of the type encountered in studies of soil-structure interaction. The concepts involved are developed by reference to viscously damped single-degree-of-freedom systems, and numerical solutions are included to illustrate the accuracy and efficiency of the proposed procedure and its superiority over the classical Discrete Fourier Transform approach. 相似文献
10.
A comprehensive analysis is made of the harmonic response of vertically excited, massless, rigid ring foundations supported at the surface of an homogeneous elastic halfspace. The parameters considered include the thickness to radius ratio for the ring, the frequency of the exciting force and of the resulting steady-state response, and Poisson's ratio for the supporting medium. The response quantities examined include the stiffness and damping coefficients of the system in an equivalent spring–dashpot representation of the supporting medium, the displacements of the foundation and of points on the ground surface away from the foundation, and the normal pressure at the foundation–medium interface. The results in each case are compared with those obtained for a solid disk having the same radius as the outer radius of the ring, and a simple approximate model is used to interpret the results and to provide insight into the action of the system. The reported data are computed by a method of analysis that takes due account of the mixed boundary conditions at the surface of the halfspace, and are believed to be of high accuracy. 相似文献