排序方式： 共有35条查询结果，搜索用时 15 毫秒
21.
It is important to know the distribution and transfer of radionuclides such as uranium, thorium, and potassium, which exist naturally in the environment we live in. For this reason, measurements of these natural radionuclides have been carried out for 15 gravel samples collected from Konyaalt? Beach, Antalya. In order to measure the natural activity concentrations of potassium-40, uranium-238, and thorium-232 radionuclides, we performed the measurements by applying a gamma spectrometry method with a “3?×?3” NaI(Tl) detector, which is a multichannel analytical detector in the Suleyman Demirel University gamma spectrometry laboratory. The minimum, maximum, and mean values for the 226Ra activity concentration were measured as 19.74 Bq/kg, 37.03 Bq/kg, and 31.64 Bq/kg, respectively. The minimum, maximum, and mean values for the 232Th activity concentration were measured as 12.76 Bq/kg, 34.32 Bq/kg, and 26.67 Bq/kg, respectively. The minimum, maximum, and mean values for the 40K activity concentration were measured as 196.37 Bq/kg, 421.13 Bq/kg, and 350.42 Bq/kg, respectively. Dose parameters and radiation damage indices were calculated using experimentally measured activity results and the resulting dose and hazard index values were compared with the determined limit values. It can be concluded that no risk may threat in terms of the hazard index values. In addition, all results obtained in terms of calculated dose values except for annual gonadal dose are below the recommended limit values. 相似文献
22.
23.
Arabian Journal of Geosciences - The uniaxial compressive and tensile strength of rocks are crucial parameters in the design stage of geotechnical structures. However, direct determination of these... 相似文献
24.
Colour origin of upper cretaceous pelagic red sediments within the Eastern Pontides, northeast Turkey 总被引：3，自引：0，他引：3
Characteristic samples of Upper Cretaceous pelagic red sediments from different parts of the Eastern Pontides (NE Turkey)
have been investigated by X-ray diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy coupled with
energy dispersive analyses (SEM/EDAX). The red sediments are composed of limestone and muddy limestone, and characterized
by abundant planktonic foraminifers. Hematite content ranges from 0.5 to 3.0 wt.%. Electron microscope observations suggest
that the hematite pigment has a diagenetic origin. The red colour is due to presence of hematite pigment, and indicates oxidizing
conditions during early diagenesis in a relatively deep marine environment.
Received: 4 January 1999 / Accepted: 8 July 1999 相似文献
25.
K��r?ad Kadir Eri? M. N. ?a?atay Sena Ak?er Luca Gasperini Yosi Mart 《Geo-Marine Letters》2011,31(1):1-18
The late glacial to Holocene sedimentary record of the northern shelf of the Sea of Marmara (SoM) has been documented by detailed
seismo-, chrono-, and biostratigraphic analyses using sub-bottom (Chirp) profiles and sediment cores. During MIS 3 and the
main part of MIS 2 (60–15 14C ka b.p.), disconnection from the Mediterranean and Black seas together with a dry climate resulted in a regression in the SoM, when
the Sea was transformed into a brackish lake. The river incisions below 105 m water depth along the northern shelf took place
during the last glacial maximum, when the lake level was modulated by stillstands at −98 and −93 m. The post-glacial freshwater
transgressive stage of the Marmara ‘Lake’ occurred between 15 and 13.5 14C ka b.p., leading to a rise in water level to −85 m by 13.0 14C ka b.p., as evidenced by broad wave-cut terraces along the northern shelf. Since 12 14C ka b.p., high-frequency sea-level fluctuations have been identified at the SoM entrance to the Strait of İstanbul (SoI). Thus, wave-cut
terraces have been recorded at water depths of −76 and −71 m that, according to an age model for core MD04-2750, have ages
of 11.5 and 10.5 14C ka b.p., respectively. Ancient shoreline at −65 m along the northern shelf presumably formed soon after the Younger Dryas (YD) at
ca. 10.1 14C ka b.p. Moreover, there is compelling evidence of Holocene outflow from the Sea of Marmara to the Black Sea. At the SoM entrance
to the SoI, the existence of bioherms on the reflector surface together with abundant Brizalina spathulata and Protoglobulimina pupoides in a core suggests a return to higher salinities due to strong Mediterranean water incursion into the SoM at ∼8.8 14C ka b.p. This finding is consistent with earlier suggestions that, after the YD, the Black Sea was flooded by outflow from the SoM
as a result of global sea-level rise. 相似文献
26.
A new Local Ocean Tide Model, has been produced for the Exclusive Economic Zone (EEZ) of Malaysia, which incorporates some of the latest TOPEX/POSEIDON data for the years 1992 to 1998. Local tide gauge data are used as a comparison, along with another leading Global Ocean Tide Model, Ori96. The leading diurnal and semidiurnal constituents M2, S2, N2, K1, O1, P1 and Q1 are reproduced using TOPEX/POSEIDON Sea Surface Heights (SSH) in a response analysis type least squares derivation following Munk and Cartwright (1966). 相似文献
27.
Kadir Dirik 《Geodinamica Acta》2013,26(1-3):147-158
AbstractCentral Anatolia has undergone complex Neotectonic deformation since Late Miocene-Pliocene times. Many faults and intracontinental basins in this region were either formed, or have been reactivated, during this period. The eastern part of central Anatolia is dominated by a NE-SW-trending, left lateral transcurrent structure named the Central Anatolian fault zone located between Sivas in the northeast and west of Mersin in the southwest. Around the central part, it is characterized by transtensional depressions formed by left stepping and southward bending of the fault zone. Pre-Upper Miocene basement rocks of the region consist of the central Anatolian crystalline complex and a sedimentary cover of Tertiary age. These rock units were strongly deformed by N-S con- vergence. The entire area emerged to become the site of erosion and formed a vast plateau before the Late Miocene. A NE-SW- trending extensional basin developed on this plateau in Late Miocene-Early Pliocene times. Rock units of this basin are characterized by a thick succession of pyroclastic rocks intercalated with calcalkaline-alkaline volcanics. The volcanic sequence is uncon- formably overlain by Pliocene lacustrine-fluviatile deposits interrelated with ignimbrites and tuffs. Thick, coarse grained alluvial/colluvial fan deposits of marginal facies and fine grained elastics and carbonates of central facies display characteristic synsedimentary structures with volcanic intercalations. These are the main lines of evidence for development of a new transtensional H?rka— k?zd?rmak basin in Pliocene times. Reactivation of the main segment of the Central Anatolian fault zone has triggered development of depressions around the left stepping and southward bending of the central part of this sinistral fault zone in the ignimbritic plateau during Late Pliocene-Quaternary time. These transtensional basins are named the Tuzla Gölü and Sultansazl??? pull-apart basins. The Sultansazl??? basin has a lazy S to rhomboidal shape and displays characteristic morphologic features including a steep and stepped western margin, large alluvial and colluvial fans, and a huge composite volcano (the Erciyes Da??).The geometry of faulting and formation of pull-apart basins can be explained within the framework of tectonic escape of the wedgelike Anatolian block, bounded by sinistral East Anatolian fault zone and dextral North Anatolian transform fault zone. This escape may have been accomplished as lateral continental extrusion of the Anatolian Plate caused by final collision of the Arabian Plate with the Eurasian Plate. © 2001 Éditions scientifiques et médicales Elsevier SAS 相似文献
28.
Chu Ling Heng Ong Hock Peng Paul Ponar Sinjeng Askury Ab. Kadir Kamuradin Md. Slar Sharifah Chu Ismail 《Journal of Asian Earth Sciences》1997,15(6):477
Medium- to coarse-grained leucocratic granitic bodies containing more than 60% feldspar and less than 10% mafic minerals are found to be appropriate and potential source materials of local feldspar. Out of the 72 granite quarries/outcrops studied in Peninsular Malaysia, 31 have been identified as “ideal” sources of feldspar conforming to the “preferred” feldspar specification of >18% Al2O3, >11% (Na2O+K2O) and <0.3% Fe2O3. A feldspar recovery efficiency exceeding 60% was achieved in this study. Despite the positive and encouraging indication that the extracted feldspar samples of different chemical composition are found to be suitable for the general purpose of making ceramic bodies and glaze, the chemical content of the feldspar, nevertheless, could be critical for the manufacture of specific end products. At 1250°C all extracted feldspar samples were fused; however, at the lower temperature of 1170°C feldspar samples extracted from some “Central Belt granites” remained unfused. The Eastern Province granites generally yielded feldspars which show better fusion characteristics i.e. (unblemished) than those extracted from the Main Range Province. A valuable by-product of the feldspar extraction process is silica sand. 相似文献
29.
Rapid analysis of risk assessment using developed simulation of chemical industrial accidents software package 总被引：1，自引：0，他引：1
M. El Harbawi Ph.D. S. Mustapha Ph.D. T. S. Y. Choong Ph.D. S. Abdul Rashid Ph.D. S. A. S. A. Kadir Ph.D. Z. Abdul Rashid M.Sc. 《International Journal of Environmental Science and Technology》2008,5(1):53-64
The environmental consequences are defined as consequences of accidental release of hazardous substances to the natural environment. This release can lead to many hazards depending on the material stored. The consequences of these hazards to the environment are widespread and have significant importance to human communities living in the surroundings. The mathematical models are extremely useful tools to predict the impacts of chemical process accidents. The objective of this paper is to develop a software package for accident simulation and damage potential estimation. The software is coded in visual basic and is compatible with windows working environments. The software is called Simulation of chemical industrial accident. This application is a comprehensive software package which can be integrated with geographical information system to predict and display the consequence of chemical hazards. The software is a user-friendly and effective tool for evaluating the consequences of major chemical accidents, process decision making for land-use planning, namely locating suitable hazardous installations, hazardous waste disposal areas and emergency response plan. 相似文献
30.
M. Arif Gurel R. Kadir Pekgokgoz Feridun Cili 《Bulletin of Earthquake Engineering》2012,10(2):587-613
In this paper, the seismic resistance of unreinforced masonry (URM) cylindrical columns is investigated with an equivalent
static analysis procedure. To this end, an existing numerical model developed for the stability analysis of masonry elements
with rectangular cross-section is utilized and modified for the cylindrical columns. In the numerical model which takes into
account the cracking of the sections and the second-order effects, the columns are divided ideally into sufficiently high
number of elements, each having uniform curvature. The columns are modeled as prismatic cantilevers undergoing their own weights,
eccentric vertical loads and distributed and concentrated static horizontal loads equivalent to the inertia actions. By considering
two examples of columns, firstly a reference column and secondly a column from a real building, lateral seismic coefficient
versus top drift level curves are obtained. On the basis of these curves, lateral load behavior of the columns is interpreted
and maximum seismic load values which can be resisted by each column are determined. Implementing parametric analyses on the
reference column, sensitivity of the seismic resistance to parameters such as column slenderness, magnitude and eccentricity
of vertical top load, and the flexibility parameter is determined. The influence of some structural imperfections such as
the deviation from vertical on the seismic resistance is also discussed in the paper. 相似文献