Ethnic residential shifts: The Greek population of Akron, Ohio, 1930–2005     

Stavros T. Constantinou 《GeoJournal》2007,68(2-3):253-265

The purpose of this paper is to apply the framework of transnationalism to the study of the Akron, Ohio Greek community through the spatio-temporal changes in the residential patterns. Church records for the period 1930 to 2005 form the basis of the study. The first Greek immigrants arrived in Akron, Ohio in the latter part of the nineteenth century and settled around the commercial zone in the central city. Additional immigrants, mostly young males with little education, arrived during the early decades of the twentieth century to seek employment in the growing industries, especially the tire factories. The establishment of a sizable colony made it possible to form a parish church in close proximity to the place of work. In addition to the place of worship, ethnic stores, and coffee houses became foci of ethnic life. Although this central city cluster was undergoing minor residential shifts to the suburbs, it was identifiable until the early 1970s. By then most of its immigrant residents as well as their American born children moved to the suburbs, especially in the northwestern part of the city, because of economic improvement. Post-1965 immigrants bypassed the central city cluster and settled in the suburbs. Anecdotal information suggests that these immigrants, individually and collectively as a group, maintain a variety of economic, social, and cultural connections with their place of origin as well as the Akron Greek community. Thus, transnationalism is an appropriate framework to study recent immigrants who maintain concurrent connections to the United States and Greece.  相似文献   

Estimated SLR station position and network frame sensitivity to time-varying gravity   总被引：1，自引：1，他引：0  

Nikita P. Zelensky  Frank G. Lemoine  Douglas S. Chinn  Stavros Melachroinos  Brian D. Beckley  Jennifer Wiser Beall  Oleg Bordyugov 《Journal of Geodesy》2014,88(6):517-537

This paper evaluates the sensitivity of ITRF2008-based satellite laser ranging (SLR) station positions estimated weekly using LAGEOS-1/2 data from 1993 to 2012 to non-tidal time-varying gravity (TVG). Two primary methods for modeling TVG from degree-2 are employed. The operational approach applies an annual GRACE-derived field, and IERS recommended linear rates for five coefficients. The experimental approach uses low-order/degree $4\times 4$ coefficients estimated weekly from SLR and DORIS processing of up to 11 satellites (tvg4x4). This study shows that the LAGEOS-1/2 orbits and the weekly station solutions are sensitive to more detailed modeling of TVG than prescribed in the current IERS standards. Over 1993–2012 tvg4x4 improves SLR residuals by 18 % and shows 10 % RMS improvement in station stability. Tests suggest that the improved stability of the tvg4x4 POD solution frame may help clarify geophysical signals present in the estimated station position time series. The signals include linear and seasonal station motion, and motion of the TRF origin, particularly in Z. The effect on both POD and the station solutions becomes increasingly evident starting in 2006. Over 2008–2012, the tvg4x4 series improves SLR residuals by 29 %. Use of the GRGS RL02 $50\times 50$ series shows similar improvement in POD. Using tvg4x4, secular changes in the TRF origin Z component double over the last decade and although not conclusive, it is consistent with increased geocenter rate expected due to continental ice melt. The test results indicate that accurate modeling of TVG is necessary for improvement of station position estimation using SLR data.  相似文献   

Upper bound analysis of tunnel face stability in layered soils   总被引：3，自引：3，他引：0  

Xiao-Wu Tang  Wei Liu  Bettina Albers  Stavros Savidis 《Acta Geotechnica》2014,9(4):661-671

The working face of tunnel constructions has to be kept stable during tunneling to prevent large soil deformations or fatal failure. In layered soils with lower cohesion, failures happen more often and more abrupt than in cohesive soils. Therefore, the maintenance of a proper support pressure at the tunnel working face is of high importance. In this paper, an upper bound analysis is introduced to investigate the minimum support pressure for the face stability in layered soils. A three-dimensional kinematically admissible mechanism for the upper bound analysis is improved to model potential failure within different soil layers. An analytical solution for the support pressure assessment is achieved. The influence of the crossing and cover soil on the face stability is analyzed, respectively. This solution provides an analytical estimation of the minimum support pressure for the face stability. It may be used as a reference for projects under similar conditions.  相似文献   

Dynamic stresses in an elastic half-space     

Winfried Schepers  Stavros Savidis  Eduardo Kausel 《Soil Dynamics and Earthquake Engineering》2010,30(9):833-843

This paper deals with the problem of time-varying point loads applied onto the surface of an elastic half-space and the stresses that such loads elicit within that medium. The emphasis is on the evaluation of the isobaric contours for all six of the stress components at various frequencies of engineering interest and for a full range of Poisson’s ratios. The extensive set of pressure bulbs presented herein may be of help in predicting the severity of dynamic effects in common practical situations in engineering—or even the lack thereof.  相似文献   

Accidental design eccentricity: Is it important for the inelastic response of buildings to strong earthquakes?     

Kyriakos G. Stathopoulos  Stavros A. Anagnostopoulos 《Soil Dynamics and Earthquake Engineering》2010,30(9):782-797

To deal with earthquake-induced torsion in buildings due to some uncertain factors, difficult to account for directly in design, modern codes have introduced the so-called accidental design eccentricity (ADE). This provision has been based primarily on elastic investigations with special classes of multi-story buildings or with simplified, one-story inelastic models. In the present paper, the effectiveness of this provision is investigated using inelastic models, both of the typical one-story, 3-DOF type, and the more sophisticated MDOF, frame idealizations of the plastic hinge type. One, three and five story, realistic, frame buildings with different natural eccentricities were designed for different ADEs, including those specified by the EC8 and IBC codes. The evaluation is made using mean peak ductility factors of the edge frames as measures of their inelastic response, obtained from dynamic analyses for ten pairs of semi-artificial earthquake motions. The simplified models indicate that the accidental design eccentricity is very effective in reducing ductility demands, especially for very stiff systems. However, this is not confirmed by the more accurate and detailed plastic hinge building models, which show that designs accounting for accidental eccentricity do not exhibit any substantial reduction or better distribution of ductility demands, compared to designs in which accidental eccentricity has been entirely ignored. These findings suggest that the ADE provisions in codes, especially the more complicated ones as in the IBC, should be re-examined, by weighting their importance against the additional computational work they impose on designers. In the cases examined herein this importance can be characterized as marginal. Obviously additional studies are required, to include more building types and earthquake motions, in order to arrive at firm conclusions and recommendations for code modifications.  相似文献   

Fast water infiltration: a mechanism for fracture formation during land subsidence     

Isaac Martinez  Reinhard Hinkelmann  Stavros Savidis 《Hydrogeology Journal》2013,21(4):761-771

A mechanism for fracture generation and for triggering land subsidence is presented. Infiltration through a pre-existing fracture zone into a two-layered system, as well as the deformation of unconsolidated sediments on the land surface, was numerically investigated. The numerical simulation of infiltration is based on a two-phase flow-model concept for porous media, and for the deformation, it is based on a Mohr-Coulomb model concept. Different studies with variations of the fracture parameter and infiltration conditions have been carried out. The infiltration results show that fast infiltration in a partially saturated aquifer leads to land subsidence, extension of pre-existing fractured zones and the generation of new cracks. If the water column is only on the fracture, the clay layer acts like a barrier and inhibits the infiltration through the fracture. If the water column covers the entire surface, the barrier effect is overcome; the infiltration intensity depends on the height of the water column, the fracture permeability and the fracture width. The deformation results show that a strong rainfall event of 2 h leads to deformations that are about 30 % of the vertical and 70 % of the horizontal annual land-subsidence rates.  相似文献   

Geochemistry and genesis of sulphide ore deposits in Sharosh Village,Qandil Series,Kurdistan Region,NE Iraq     

Tola A. Mirza  Stavros P. Kalaitzidis  Sarkhel H. Mohammed  Saman Gh. Rashid  Xenia Petrou 《Arabian Journal of Geosciences》2017,10(19):428

The low-grade base metal sulphide Cu–Zn–Pb and Fe mineralization of Qandil Series develop in shear zones that occur in formations of the north-western part of the Zagros Orogen. This sulphide mineralization occurs either as quartz vein type or disseminated type associated with metamorphic rocks (marbles and phyllites). This study aims to characterize these sulphide-rich ores by means of their mineralogical and geochemical features, including also the features of the corresponded host formations and those of marbles (calcitic and dolomitic) and phyllites. Petrographical data indicate the presence of Cu, Zn, Pb and Fe sulphides in hydrothermal quartz (±calcite) veins of different generations. Geochemical data of surface samples indicate enrichment of Cu and Fe in shear zones with low concentrations in Zn and Pb. The REE data indicate that the genesis of these sulphide ores took place in a hydrothermal system and was generally attributed to high temperature (> 250 °C).The mineralization seems to be fault-controlled, which is favoured by the significant tectonic deformation of the area.  相似文献   

Influence of the Sedimentary Cover in the Cologne Area on the Shape of Response Spectra     

J. Röhner  S. A. Savidis 《Natural Hazards》2006,38(1-2):215-227

For the greater area of the city of Cologne a microzonation from an earthquake engineering perspective was introduced. The area has been divided into eight subregions with approximately uniform soil profile. For all regions the influence of the sediments on simulated earthquakes has been investigated by three well known methods: 2-layer solution, SHAKE 91, HASKELL matrix algorithm. The transfer functions and response spectra were computed and compared to the elastic acceleration response spectra of the German building code E-DIN 4149. Two different methods for the generation of synthetic accelerograms and the three wave propagation analysis procedures have been compared and a series of issues relevant to the practical application of them were discussed.  相似文献   

Revision of the EU Bathing Water Directive: economic costs and benefits     

Georgiou S  Bateman IJ 《Marine pollution bulletin》2005,50(4):430-438

The European Union (EU) Bathing Water Directive of 1976 ([Commission of the European Communities, 1976. Council Directive of 8th December 1975 Concerning the Quality of Bathing Water (76/160/EEC). Official Journal of the European Community. 5th February 1976, L31/1, Brussels]) sets out standards for designated bathing waters which should be complied with by all member states. Intervening advances in pollution science, related technology and managerial expertise have allowed the European Commission to consider revision of EU environmental legislation where appropriate. As a result, a number of revisions to the 1976 Directive have been proposed ([Commission of the European Communities, 1994. Commission Proposal for a Council Directive Concerning the Quality of Bathing Water. Communication from the Commission to the European Parliament and the Council, COM (94) 36 Final, Brussels; Commission of the European Communities, 2000. Developing a New Bathing Water Policy, Communication from the Commission to the European Parliament and the Council, COM (2000) 860 Final, 21/12/200, Brussels; Commission of the European Communities, 2002. Commission Proposal for a Directive of the European Parliament and of the Council Concerning the Quality of Bathing Water, COM (2002) 581 Final, 24/10/2002, Brussels]). This paper considers these revisions in terms of the economic costs and benefits associated with any change in policy. The focus is on the public's willingness to pay for a revised Directive and the consequent public health benefits afforded to individuals and society. These economic benefits are compared to the costs of implementing changes to bring bathing waters up to the required standard.  相似文献   

Humic and Fulvic Acids as Potentially Toxic Metal Reducing Agents in Water          下载免费PDF全文

Stavros Lalas  Vasilios Athanasiadis  Vassilis G. Dourtoglou 《洁净——土壤、空气、水》2018,46(2)

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