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1.
Modulus of subgrade reaction is one of the required design parameters in any structural analyses of shallow foundations. However, the constant values of modulus of subgrade reaction that are determined from either from literature studies or the results of plate load tests, regardless of magnitude of soil’s displacement under design loads, have been used in structural designs of foundations. In this study, the results of 43 published full-scale field plate load tests in cohesionles soils were gathered to expose any variation in the values of modulus of subgrade reaction as soil’s displacement increases. Extensive finite element (FE) analyses were carried out while the results of FE analyses were compared with actual measured results of field load tests. The results of analyses indicated that both the modulus of subgrade reaction decrease with increase in magnitude of displacement of soils and internal forces of a design of structural frame is higher with the values of modulus of subgrade reaction that are sensitive to soil’s displacement are implemented into analyses. Therefore, structural dimensions of any structure with the constant values of modulus of subgrade reaction would not be a precise engineering solution. 相似文献
2.
Izmir Bay is one of the most polluted estuaries in the whole Mediterranean Sea. The inner part of the Bay (Inner Bay) is heavily
affected by domestic and industrial discharge. As a result of these loads, strong eutrophication occurs in the Inner Bay,
which is temporally anaerobic. The ecologically sensitive approach of the local authorities during the last decade has given
rise to a wide variety of monitoring and research studies on this bay. On the other hand, the municipality of Izmir started
to operate wastewater treatment facilities since January 2000. The Institute of Marine Sciences and Technology — Izmir (IMST)
with its research vessel R/V K Piri Reis has been conducting an intensive monitoring program since 1988 and especially during
the recent few years. These investigations provide an opportunity for the evaluation of the performance of the wastewater
treatment plant in terms of the change in the optical properties of Izmir Bay water in a positive manner. The turbidity values
measured in these monitoring studies indicate that the values have changed drastically after January 2000. Their spatial variation
indicates that the values decrease from the Inner Bay towards the Aegean Sea. The turbidity (light transmission) values are
measured with an automatic CTD (conductivity, temperature and depth) system during each cruise. The seiche disc depth measurement
is carried out only occasionally. The accuracy of the seiche disc depth is dependent on certain daylight conditions and depends
on the operator. The seiche disc depth (D
s) is an important parameter to estimate primary production of organic matter (hereafter called production). A relation between
light transmission (turbidity) value and seiche disc depth (D
s) is found with very good agreement. The correlations are very high (approximately 0.94) with slight seasonal variation. 相似文献
3.
This paper presents probable effects of climate change on soil moisture availability in the Southeast Anatolia Development Project (GAP) region of Turkey. A series of hypothetical climate change scenarios and GCM-generated IPCC Business-as-Usual scenario estimates of temperature and precipitation changes were used to examine implications of climate change for seasonal changes in actual evapotranspiration, soil moisture deficit, and soil moisture surplus in 13 subregions of the GAP. Of particular importance are predicted patterns of enhancement in summer soil moisture deficit that are consistent across the region in all scenarios. Least effect of the projected warming on the soil moisture deficit enhancement is observed with the IPCC estimates. The projected temperature changes would be responsible for a great portion of the enhancement in summer deficits in the GAP region. The increase in precipitation had less effect on depletion rate of soil moisture when the temperatures increase. Particularly southern and southeastern parts of the region will suffer severe moisture shortages during summer. Winter surplus decreased in scenarios with increased temperature and decreased precipitation in most cases. Even when precipitation was not changed, total annual surplus decreased by 4 percent to 43 percent for a 2°C warming and by 8 percent to 91 percent for a 4°C warming. These hydrologic results may have significant implications for water availability in the GAP as the present project evaluations lack climate change analysis. Adaptation strategies – such as changes in crop varieties, applying more advanced dry farming methods, improved water management, developing more efficient irrigation systems, and changes in planting – will be important in limiting adverse effects and taking advantage of beneficial changes in climate. 相似文献
4.
Spectral and Spatial Quality Analysis in Pan Sharpening Process 总被引：1，自引：0，他引：1
Image fusion is a process to obtain new images containing more information by combining images obtained same or different sensors. With most of the earth observation satellites, high spatial resolution panchromatic images and low spatial resolution multispectral images are obtained. As an example of image fusion ??pan sharpening?? is a process of combining of high spatial resolution panchromatic images and low spatial resolution multispectral images. At the end of the fusion process both high spatial and spectral resolution new images are obtained. In this study, panchromatic and multispectral images gathered from Ikonos were used. Panchromatic and multispectral images belonging to the same sensor were combined by using different image fusion methods. As pan sharpening methods Brovey transform, Modified IHS, Principal Component Analysis (PCA), Wavelet PC transform and Wavelet A Trous transformation methods were used. Quality of fused products was evaluated from the point of view of both visual and statistical criteria. While wavelet based methods are succesfull in terms of protection of spectral quality of original multispectral images, the colorbased and statistical methods are giving better results within the improvement of spatial content. 相似文献
5.
In this study, it was aimed to determine the effect of various aeration rates on composting to supply the optimum aeration rate for a successful and economic composting. For this aim, vegetable–fruit wastes (VFW) were composted at various aeration rates (0.37, 0.49, 0.62, 0.74, 0.86, and 0.99 L/min kg VS) and moisture, temperature, pH, electrical conductivity, C/N, and cellulose were investigated. Moistures of the reactor that had the highest aeration were generally lower than those of the others. Reactor that had the lowest aeration reached thermophilic phase earlier than the others and stayed more days. This situation was opposite for the reactor that had the highest aeration. pH variations with aeration rates were not significant. Although electrical conductivity did not differ significantly with aeration rates, at the beginning of the thermophilic phase it generally increased with the increase in aeration. The highest C/N reduction was observed in the reactor that had an aeration of 0.62 L/min kg VS. The final cellulose contents were close to each other. It could be said that aeration rates used were efficient on composting of VFW. Taking the C/N into account which is the parameter of the indicator of the stabilization in composting, it could be said that the optimum aeration rate for forced aerobic composting of VFW was 0.62 L/min kg VS. 相似文献
6.
M. E. Ayhan 《Journal of Geodesy》1997,71(6):362-369
In the analyses of 2D real arrays, fast Hartley (FHT), fast T (FTT) and real-valued fast Fourier transforms are generally
preferred in lieu of a complex fast Fourier transform due to the advantages of the former with respect to disk storage and
computation time. Although the FHT and the FTT in one dimension are identical, they are different in two or more dimensions.
Therefore, first, definitions and some properties of both transforms and the related 2D FHT and FTT algorithms are stated.
After reviewing the 2D FHT and FTT solutions of Stokes' formula in planar approximation, 2D FHT and FTT methods are developed
for geoid updating to incorporate additional gravity anomalies. The methods are applied for a test area which includes a 64×64
grid of 3′×3′ point gravity anomalies and geoid heights calculated from point masses. The geoids computed by 2D FHT and FTT are found to
be identical. However, the RMS value of the differences between the computed and test geoid is ±15 mm. The numerical simulations
indicate that the new methods of geoid updating are practical and accurate with considerable savings on storage requirements.
Received: 15 February 1996; Accepted: 22 January 1997 相似文献
7.
uayip Küpeli M. Muzaffer Karadag Ahmet Ayhan Adnan Dyen Fetullah Ar&#x;k 《Chemie der Erde / Geochemistry》2007,67(4):313-322
The Attepe district consists of Precambrian, Lower–Middle Cambrian, Upper Cambrian–Lower Ordovician and Mesozoic formations. It contains several iron deposits and occurrences. Three types of iron-mineralizations can be distinguished in the area; (i) Sedimentary Fe-sulfide in Precambrian bituminous metapelitic rocks, and Fe-oxides in Precambrian metasandstones (SISO), (ii) vein-type Fe-carbonate and oxides composed of mainly siderite, ankerite and hematite including barite in Lower–Middle Cambrian metacarbonates of the Çaltepe Formation (HICO), (iii) karstic Fe-oxides and hydroxides essentially in the Lower–Middle Cambrian metacarbonates and the unweathered Fe-carbonates (KIO). The latter type is more widespread and located at the upper parts of the most important mineable iron deposits like Attepe deposit.
Oxygen-, carbon-, sulfur- and strontium-isotope studies have been performed on siderites and barites in the vein-type ores, and on calcites in the recrystallized Çaltepe Limestones to investigate the sources and formation mechanism of primary ore-forming constituents. The δ13C values of siderites and calcites in limestones of the Çaltepe Formation range from −10.10‰ to −8.20‰, and from −0.8‰ to 2.30‰. Both carbonate minerals show δ18O values between 17.50–18.30‰ and 16.20–23.00‰, respectively. The δ13C and δ18O isotopic variations do not indicate any direct or linear relations between siderites and limestones. However, it is possible that the carbon and oxygen isotopic compositions of carbonate minerals could be changed to some extent, when limestones were subjected to hydrothermal processes or thermal alterations during metamorphism.
The isotopic values of barites display 32.40–38.30‰ for δ34S and 12.20–14.70‰ for δ18O. The strontium isotope ratios (0.717169–0.718601) of barites and the sulfur isotope compositions of barites and pyrites suggest that there are no direct linkages of ore-forming compounds neither with a magmatic source nor with sedimentary pyrite formations in the Precambrian bituminous shales of the Attepe formation.
According to the field observations and the stable isotope data, siderites and ankerites should be formed by interaction between iron-rich hydrothermal fluids and Çaltepe limestones, whereas isotope ratios of barites indicate that they were formed by mixing of sulfur-rich meteoric waters and deeply circulated hydrothermal solutions. 相似文献
8.
Ayhan Gurbuz 《Environmental Earth Sciences》2011,64(3):883-892
A new simplified method based on one-dimensional displacement theory and 2-D finite element (FE) analysis was developed to
predict the vertical displacement behavior of a concrete-faced rockfill dam. The FE analyses were carried out at the end of
construction (EOC) and the end of first filling of reservoir. The proposed method was calibrated by using continuously monitored
vertical displacement of the dam’s body to determine the mobilized modulus of elasticity of the rockfills at the EOC. The
prediction capability of the method was demonstrated using field measurements against the findings from the 2-D FE analysis
simulating characteristics of construction stages of the dam. The validity of the method was also examined on another membrane-faced
rockfill dam by comparing the geodetic measurements of vertical displacement measurements of the dam’s body with the calculated
vertical displacements from 2-D FE analysis at the EOC. 相似文献
9.
Dicle Bal Akkoca Melek Yιlgιn Melek Ural Hasan Akçin Ayhan Mergen 《Geochemistry International》2013,51(6):495-504
The clinoptilolite rich zeolite from Bigadiç which was formed from alteration of volcanic glass were treated with acidic (HCl, H3BO3, H3PO4), alkaline (KOH, NaOH) solutions. Hydrothermally treated and untreated samples were heat treated at 400, 550 and 700°C. XRD, ICP-MS and N2 gas adsorption were used for physicochemical characterization of zeolites. Considering the Si/Al > 4 and Na+K/Ca+Mg < 1 ratios, zeolite sample is included to earth alkali clinoptilolite class (Heu II) which is also revealed by thermal treatments. Since zeolite structure contains low alkalies it was at collapsed 550°C. The removal of oxide elements efficiency of acids and alkalies were in the order of HCl > H3PO4 > HBO3 > KOH > NaOH. XRD analysis indicated that the structure of zeolite was not altered with acids and alkali treatments. The structure of zeolite treated with HCl and other acids started to deform at 400 and 550°C respectively. In treatment with HCl, Si/Al ratio increases with significant a decrease in K content which resulted in a decrease in the heat stability of zeolite. No change was observed in the structure and thermal stability of clinoptilolite after alkali treatments. The fact that although significant amount of Na is removed with H3BO3 acid and Na is increased with NaOH but the thermal stability remains the same indicates that Na cation is not an important parameter as much as K. HCl and H3PO4 acid treatments increased the surface area depending on the dissolution of amorphous material and H3PO4 was found to be more effective. However, the total pore size decreased due to formation of new micropores. 相似文献
10.
Seismic hazard analysis of Sinop province,Turkey using probabilistic and statistical methods 总被引：1，自引：0，他引：1
Recai Feyiz Kartal Günay Beyhan Ayhan Keskinsezer 《Journal of Earth System Science》2014,123(3):565-579
Using 4.0 and greater magnitude earthquakes which occurred between 1 January 1900 and 31 Dec 2008 in the Sinop province of Turkey this study presents a seismic hazard analysis based on the probabilistic and statistical methods. According to the earthquake zonation map, Sinop is divided into first, second, third and fourth-degree earthquake regions. Our study area covered the coordinates between 40.66°– 42.82°N and 32.20°– 36.55°E. The different magnitudes of the earthquakes during the last 108 years recorded on varied scales were converted to a common scale (Mw). The earthquake catalog was then recompiled to evaluate the potential seismic sources in the aforesaid province. Using the attenuation relationships given by Boore et al. (1997) and Kalkan and Gülkan (2004), the largest ground accelerations corresponding to a recurrence period of 475 years are found to be 0.14 g for bedrock at the central district. Comparing the seismic hazard curves, we show the spatial variations of seismic hazard potential in this province, enumerating the recurrence period in the order of 475 years. 相似文献