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1.
The present study aims to compute the temporal and spatial distribution of road traffic induced noise pollution in an urban environment by monitoring and mapping. The study area was the entire Asansol city of West Bengal, India. A total of 35 locations were selected for collection of data, classified as industrial, commercial, residential, sensitive and mixed areas according to the national regulatory standards. Noise recordings were conducted during morning and night hours. Day time Leq level ranged between 51.2 and 89.0 dB(A), whereas it ranged between 43.5 and 81.9 dB(A) during night. The average Ldn value was 73.28 ±8.51 dB(A) (Range: 55.1–87.3); The traffic noise index was 80.62 ± 15.88 dB(A) (Range: 49.4–115.8). The computed data were mapped by utilization of Geographic information system methodology that allowed the visualization and identification of the extent and distribution of sound pollution across the study area. This proves to be an ideal tool for carrying out noise impact assessments in urban settings. The study reveals that present noise level in all the locations exceeds the prescribed limit. Based on the finding, it can be mentioned that the population in this industrial town are exposed to significantly high noise level, which is caused mostly due to road traffic. The study reveals that vulnerable establishments like schools and hospitals are subjected to significantly high noise level throughout the day and immediate mitigatory measures are required to alleviate the problem.  相似文献   

2.
The main purpose of the study is to develop a general prediction model and to investigate the relationships between sound level produced during drilling and physical properties such as uniaxial compressive strength, tensile strength and percentage porosity of sedimentary rocks. The results were evaluated using the multiple regression analysis taking into account the interaction effects of various predictor variables. Predictor variables selected for the multiple regression model are drill bit diameter, drill bit speed, penetration rate and equivalent sound level produced during rotary drilling (L eq). The constructed models were checked using various prediction performance indices. Consequently, it is possible to say that the constructed models can be used for practical purposes.  相似文献   

3.
Strong tectonic earthquakes within the crust always occur on already existing faults, and they have the property of a shear rupture. Such earthquakes with surface-wave magnitudes M < 7 obviously have a geometric similarity. Because of this similarity and the validity of the Gutenberg and Richter's energy—magnitude relation, the expression M = 2 log10 L + const., with L = focal length, is valid.The expression LmaxL* for the maximum focal length, is also valid if L* is the length of the rectilinear extent of the seismic line on which the maximum earthquake occurs. The bounds of L* may be given by sharp bends and/or by traversing deep faults. Thus the maximum imaginable earthquake on a seismic line with the length L* has the magnitude Mmax = 2 log10 L* + const.For the investigated region — the Alps and adjacent areas — from the data of recent and historical strong earthquakes, it follows that Mmax = 2 log10 L* + 1.7, if L* is measured in kilometres. These limiting values lie in the centre-field of the magnitude range for maximum earthquakes, published by Shebalin in 1970. By the aid of this equation it is also possible to assess the upper limiting value of the accompanying maximum scale intensity.  相似文献   

4.
This paper investigates the effect of model scale and particle size distribution on the simulated macroscopic mechanical properties, unconfined compressive strength (UCS), Young’s modulus and Poisson’s ratio, using the three-dimensional particle flow code (PFC3D). Four different maximum to minimum particle size (d max/d min) ratios, all having a continuous uniform size distribution, were considered and seven model (specimen) diameter to median particle size ratios (L/d) were studied for each d max/d min ratio. The results indicate that the coefficients of variation (COVs) of the simulated macroscopic mechanical properties using PFC3D decrease significantly as L/d increases. The results also indicate that the simulated mechanical properties using PFC3D show much lower COVs than those in PFC2D at all model scales. The average simulated UCS and Young’s modulus using the default PFC3D procedure keep increasing with larger L/d, although the rate of increase decreases with larger L/d. This is mainly caused by the decrease of model porosity with larger L/d associated with the default PFC3D method and the better balanced contact force chains at larger L/d. After the effect of model porosity is eliminated, the results on the net model scale effect indicate that the average simulated UCS still increases with larger L/d but the rate is much smaller, the average simulated Young’s modulus decreases with larger L/d instead, and the average simulated Poisson’s ratio versus L/d relationship remains about the same. Particle size distribution also affects the simulated macroscopic mechanical properties, larger d max/d min leading to greater average simulated UCS and Young’s modulus and smaller average simulated Poisson’s ratio, and the changing rates become smaller at larger d max/d min. This study shows that it is important to properly consider the effect of model scale and particle size distribution in PFC3D simulations.  相似文献   

5.
The effect of coal composition, particularly the organic fraction, upon gas sorption has been investigated for Bowen Basin and Sydney Basin, Australia coals. Maceral composition influences on gas retention and release were investigated using isorank pairs of hand-picked bright and dull coal in the rank range of high volatile bituminous (0.78% Ro max) to anthracite (3.01% Ro max). Adsorption isotherm results of dry coals indicated that Langmuir volume (VL) for bright and dull coal types followed discrete, second-order polynomial trends with increasing rank. Bright coals had a minimum VL at 1.72% Ro max and dull coals had a minimum VL at 1.17% Ro max. At low rank, VL was greater in bright coal by about 10 cm3/g, but as rank increased, the bright and dull trends converged and crossed at 1.65% Ro max. At ranks higher than 1.65% Ro max, both bright and dull coals followed similar trends. These competing trends mean that the importance of maceral composition on VL varies according to rank. In high volatile bituminous coals, increases in vitrinite content are associated with increases in adsorption capacity. At ranks higher than medium to low volatile bituminous, changes in maceral composition may exert relatively little influence on adsorption capacity. The Langmuir pressure (PL) showed a strong relationship of decreasing PL with increasing rank, which was not related to coal type. It is suggested that the observed trend is related to a decrease in the heterogeneity of the pore surfaces, and subsequent increased coverage by the adsorbate, as coal rank increases. Desorption rate studies on crushed samples show that dull coals desorb more rapidly than bright coals and that desorption rate is also a function of rank. Coals of lower rank have higher effective diffusivities. Mineral matter was found to have no influence on desorption rate of these finely crushed samples. The evolution of the coal pore structure with changing rank is implicated in diffusion rate differences.  相似文献   

6.
Evaluation of the hydraulic conductivity of aquifers with piles   总被引:2,自引:0,他引:2  
Distributed piles are often installed in the foundation pit in sandy soil before dewatering. Hydraulic conductivity should be estimated considering the block effect of piles on groundwater seepage. Research shows that the effective medium theory (EMT) could be used to calculate the equivalent hydraulic conductivity (k eq) of a heterogeneous medium with other material inclusions. In order to verify the applicability of EMT in an aquifer with piles, an experimental investigation is conducted. In this experiment, a sandy soil is considered as an aquifer and polyvinylchloride pipes are adopted as piles. Piles are distributed in rectangular and triangular layouts. The relationship between k eq of the aquifer and the volume replacement ratio is plotted for these two layouts. The results indicate that EMT could well predict k eq for the cases with the rectangular layout; however, for triangular layouts, the prediction becomes poor. To provide a better prediction of k eq of the aquifer with piles distributed in a triangular layout, a modified EMT (MEMT) is proposed, in which a correction factor is adopted considering different layouts of piles. The MEMT can provide better k eq predictions for an aquifer with piles in the triangular layout pattern than those obtained using the EMT.  相似文献   

7.
Summary The high-alumina metapelites and the orthogneisses of the lower tectonic unit of East Rhodope underwent high P/T metamorphism followed by partial reequilibration during decompression under epidote-amphibolite/amphibolite facies to greenschist facies conditions. The high P/T mineral paragenesis in the orthogneisses is: quartz + albite + microcline + phengite (Simax = 7 atoms p.f.u.) + biotite and in the high alumina metapelites: garnet + chloritoid + chlorite + phengite (Simax. = 6.85 atoms p.f u.) + paragonite + quartz. Pressures between 14 and 15.5 kbar, for Tmin = 550°C, are estimated for the high P/T metamorphism. During continuing uplift, staurolite + chlorite, staurolite + biotite and finally andalusite + Fe-ripidolite are grown at the expense of chloritoid in metapelites, while in the orthogneisses oligoclase, still coexisting with albite, is formed; in both rock types the Si content of white K-mica decreases considerably from almost pure phengite to pure muscovite.
Hochdruck-Metamorphose in Gneisen und pelitischen Schiefern der östlichen RhodopeZone, Nord-Griechenland
Zusammenfassung Die Aluminium-reichen Metapelite und die Orthogneise der unteren tektonischen Einheit der östlichen Rhodope-Zone wurde unter hohen Drucken und Temperaturen metamorphosiert. Darauf folgte eine teilweise Reequilibration unter Druck-Entlastung bei Bedingungen der Epidot-Amphibolit/Amphibolit bis Grünschiefer Fazies. Die Hoch-P/T Mineral-Assoziation in den Orthogneisen besteht aus: Quarz + Albit + Mikroklin + Phengit (Simax = 7 atoms p.f.u.) + Biotit und in den Aluminium-reichen Metapeliten: Granat + Chloritoid + Chlorit + Phengit (Simax = 6.85 atoms p.f.u.) + Paragonit + Quarz. Drucke zwischen 14 and 15.5 kbar für Tmin = 550°C wurden für die Hoch- P/T Metamorphose berechnet. Während andauernder Anhebung bildeten sich Staurolit + Chlorit, Staurolit + Biotit und schließlich Andalusit + Fe-Ripidolit auf Kosten von Chloritoid in den Metapeliten, während in den Orthogneisen Oligoklas der noch mit Albit koexistiert, gebildet wurde; in beiden Gesteinstypen nimmt der Si-Gehalt heller Kaliglimmer von fast reinem Phengit bis zu reinem Muskowit ab.
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8.
In situ stress measurements by hydraulic fracturing were carried out in the 617 m deep borehole specially drilled in the epicentral zone of the 1993 Latur earthquake for the purpose of research. The stress measurements carried out at 592 m depth in this borehole are the deepest of all such measurements made so far in the Indian shield. The maximum and minimum principal horizontal stresses (S H max andS h min) have been derived from the hydrofracture data using the classical method. TheS H max andS h min are found to be 16.5 and 9.6 MPa at 373 m depth, and 25.0 and 14.1 MPa at 592 m depth, indicating that the vertical gradients ofS hmax andS hmin in the epicentral zone are 39 MPa/km and 21 MPa/km respectively. The principal horizontal stresses in the epicentral zone are comparable with those at Hyderabad and 30% higher than in most other comparable intra-continental regions. Analysis of the results indicate that the stresses in the focal region of the 1993 Latur earthquake have not undergone any significant change following its occurrence and this is in agreement with a similar inference drawn from the seismic data analysis. It appears that the Latur earthquake was caused due to rupturing of the overpressured fault segment at the base of the seismogenic zone.  相似文献   

9.

The Naozhi Au–Cu deposit is located on the continental margin of Northeast China, forming part of the West Pacific porphyry–epithermal gold–copper metallogenic belt. In this paper, we systematically analyzed the compositions, homogenization temperatures, and salinity of fluid inclusions as well as their noble gas isotopic and Pb isotopic compositions from the deposit. These new data show that (1) five types of fluid inclusions were identified as pure gas inclusions (V-type), pure liquid inclusions (L-type), gas–liquid two-phase inclusions (W-type, as the main fluid inclusions (FIs)), CO2-bearing inclusions (C-type), and daughter-mineral-bearing polyphase inclusions (S-type); (2) W-type FIs in quartz crystals of early, main, and late stage are homogenized at temperatures of 324.7–406.7, 230–338.8, and 154.6–308 °C, with salinities of 2.40–7.01 wt% NaCleq, 1.73–9.47 wt% NaCleq, and 6.29 wt% NaCleq, respectively. S-type FIs in quartz crystals of early stage are homogenized at temperatures of 328.6–400 °C, with salinities of 39.96–46.00 wt% NaCleq; (3) Raman analysis results reveal that the vapor compositions of early ore-forming fluids consisted of CO2 and H2O, with H2O gradually increasing and CO2 being absent at the late mineralization stage; (4) fluid inclusions in pyrite and chalcopyrite have 3He/4He ratios of 0.03–0.104 Ra, 20Ne/22Ne ratios of 9.817–9.960, and 40Ar/36Ar ratios of 324–349. These results indicate that the percentage of radiogenic 40Ar* in fluid inclusions varies from 8.8 to 15.5 %, containing 84.5–91.2 % atmospheric 40Ar; (5) the 206Pb/204Pb, 207Pb/204Pb, and 206Pb/204Pb ratios of sulfides are 18.1822–18.3979, 15.5215–15.5998, and 38.1313–38.3786, respectively. These data combined with stable isotope data and the chronology of diagenesis and metallogenesis enable us suppose that the ore-forming fluids originated from the melting of the lower crust, caused by the subduction of an oceanic slab, whereas the mineralized fluids were exsolved from the late crystallization stage and subsequently contaminated by crustal materials/fluids during ascent, including meteoric water, and the mineral precipitation occurred at a shallow crustal level.

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10.
Carbonate minerals and water (or geofluids) reactions are important for modeling of geochemical processes and have received considerable attention over the past decades. The calcite dissolution rates from 50℃ to 250℃ at 10 MPa in deionized water with a flow rate varying from 0.2 to 5 mL/min were experimentally measured in a continuous flow column pressure vessel reactor. The dissolution began near the equilibrium with c/ceq 〉 0.3 and finally reached the equilibrium at 100℃-250℃, so the corresponding solubility was also determined as 1.87, 2.02, 2.02 and 1.88×10^-4.mol/L at 100℃, 150℃, 200℃ and 250℃ respectively, which was first increasing and then switching to decreasing with temperature and the maximum value might occur between 150℃ and 200℃. The experimental dissolution rate not only increased with temperature, but also had a rapid increase between 150℃ and 200℃ at a constant flow rate of 4 mL/min. The measured dissolution rates can be described using rate equations of R = k(1-c/ceq)n or R = kc-n. In these equations the reaction order n changed with temperature, which indicates that n was a variable rather than a constant, and the activation energy was 13.4 kJ/mol calculated with R = k(1-c/ceq)n or 18.0 kJ/mol with R = kc^-n, which is a little lower than the surface controlled values. The varied reaction order and lower activation energy indicates that calcite dissolution in this study is a complex interplay of diffusion controlled and surface controlled processes.  相似文献   

11.
Noise exposure has become one of the most important factors in determining the quality of life in indoor environments. This paper assesses and analyzes noise exposure levels at school and preschool classrooms with different indoor environments. The sound level [A-weighting equivalent steady sound level L Aeq (dBA)] was measured using a CEL-63× digital sound level meter. The noise level measurements were performed inside two preschools at three classrooms (an activity room, classroom KG1 and classroom KG2) and three schools at different classrooms, starting from grade 1 to grade 12. The logarithmic average noise levels (L Aeq avg) and the 8-h average noise exposure level (L EX, 8-h) were estimated for each classroom. Furthermore, health risk issues associated with the exposure to high noise levels were investigated using a questionnaire and an interview with more than 250 teachers at the preschools and the schools. Then, the results were analyzed using different statistical tools and were compared with the World Health Organization, Occupational Health and Safety and National Institute for Occupational Safety and Health standards. Also, the results were compared with those from different countries worldwide. The study results show that the 8-h average noise exposure level exceeded the allowable limits in some schools, which indicates that students and teachers can face a serious health effects from noise exposure. The comparisons show that the values of noise levels in Kuwait are higher than those in different countries. The maximum value of noise levels was found in secondary schools. The health problems found during the survey are potentially associated with issues related to hearing, voice, headache and the physiological function of teachers.  相似文献   

12.
On the formation of granulites   总被引:23,自引:0,他引:23  
The tectonic settings for the formation and evolution of regional granulite terranes and the lowermost continental crust can be deduced from pressure–temperature–time (P–T–time) paths and constrained by petrological and geophysical considerations. P–T conditions deduced for regional granulites require transient, average geothermal gradients of greater than 35°C km?1, implying minimum heat flow in excess of 100 mWm?2. Such high heat flow is probably caused by magmatic heating. Tectonic settings wherein such conditions are found include convergent plate margins, continental rifts, hot spots and at the margins of large, deep-seated batholiths. However, particular P–T–time paths do not allow specific tectonic settings to be distinguished at this time. Under different conditions, both clockwise, CW (Pmax attained before Tmax), and anticlockwise, ACW (Pmax attained slightly after Tmax), paths are possible in the same tectonic setting. Both CW and ACW end-member paths can yield nearly isobaric cooling, IBC, paths. Such cooling paths are clearly not an artefact of thermobarometry, but can be constrained by solid–solid and devolatilization equilibria and geophysical modelling. In terms of understanding the evolution of the deep crust, a potentially significant group of regional granulite terranes are those that show evidence for ACW-IBC paths. Such paths are the likely result of: (i) episodic igneous activity resulting in intrusions within all levels of the crust, (ii) thickening of the crust by magmatic underplating, (iii) slow uplift as a result of the formation of a deep, garnet-rich crustal root and (iv) excavation resulting from a later tectonic event unrelated to that resulting in the formation of the granulites. The later event might be triggered by the delamination of the garnet-rich, lowermost crust.  相似文献   

13.
Hg in hydrothermal systems is generally thought to be transported as Hg-S complexes. However, the abundance of Hg0vap, in geothermal emissions suggests that Hg0eq, is present in the liquid phase of geothermal systems. Calculations for reducing fluids (HS? dominant over SO=4) in equilibrium with cinnabar indicate that Hg0eq, can be quite abundant relative to other species at temperatures above 200°C. Increasing pH and temperature, and decreasing total S, ionic strength, and pO2 all promote the abundance of Hg0eq. When a vapor phase develops from a geothermal liquid, Hg partitions strongly into the vapor as Hg0vap. Vapor transport at shallow level then results in the formation of Hg halos around shallow aquifers as well as in a flux of Hg to the atmosphere. Hg deposition may occur in response to mixing with oxidizing or acidic water, turning Hg0eq, into Hg++, with subsequent cinnabar precipitation. When pyrite is the stable Fe-sulfide, cinnabar solubility is at its lowest, so cinnabar + pyrite assemblages are common. Cinnabar + hematite ± pyrite can precipitate from more oxidized or S-poor water. Hg0liq, can occur as a primary mineral, in coexistence with all common Fe-sulfides and oxides. Cinnabar ± Hg0liq cannot coexist with pyrrhotite or magnetite at temperatures between 100° and 250°C. Evidence from Hg deposits indicates that many formed from dilute hydrothermal fluids in which Hg probably occurred as Hg0eq. In S-rich systems, Hg may occur as Hg-S complexes, and in saline waters it can occur as Hg-Cl complexes.  相似文献   

14.
靖远黄土剖面磁性地层的初步研究   总被引:23,自引:3,他引:23       下载免费PDF全文
曹岘黄土剖面位于甘肃省靖远县,系黄河中游六级阶地黄土堆积,厚约505m,含33层古土壤,系黄土-古土壤系列,是目前已知世界上最厚的黄土剖面。作者对该剖面进行了古地磁学研究,结果表明:曹岘黄土剖面含布容正极性时和松山反极性时,B/M 界线位于L8中部,加拉米洛正极性亚时位于L10—L13,位置。曹岘黄土堆积始于1.40MaB.P.,该黄土剖面可以与兰州、洛川和蓝田等黄土剖面对比。  相似文献   

15.
Raman spectroscopy was used as a supplementary method to characterise the thermal maturity of Ediacaran organic matter (OM) from the East European Craton. Because this method is based on organic particles measurement, it appears to be a good supplementary method in addition to the acquisition of biomarker data, which is based on extractable organic matter and may be affected by potential contamination. Raman spectroscopy seems to be particularly useful for lower Palaeozoic rocks, which do not contain vitrinite. Here, we compared C31 22S/(S + R) homohopane ratio results (obtained using gas chromatography – mass spectrometry), with various Raman parameters including: G_STA, Gmax position, Dmax/Gmax, FWHMG, RAR, D_STA, and PDmax. Close correlations were observed between C31 22S/(S + R) and G_STA, Gmax position, Dmax/Gmax, and FWHMG, reaching values of R2 = 0.5‒0.6, whereas no correlation existed between homohopane ratio and the RAR, D_STA, and PDmax parameters. Raman spectroscopy results divided Ediacaran samples into two distinctive groups: (i) immature (Russian, Lithuanian, and Belarusian), characterised by relatively higher values of G_STA, Dmax/Gmax, and FWHMG and relatively lower values of PGmax, and (ii) mature (Polish and Ukrainian), with relatively lower values of G_STA, Dmax/Gmax, and FWHMG and relatively higher values of PGmax. Within each group no statistically confirmed differences were found. However, significant discrepancies were observed between the hopane ratio and Raman parameters in Lithuanian samples, in relation to other samples from the group (i). Values of the C31 22S/(S + R) ratio for Lithuanian samples are close to those for the group (ii) and significantly higher than those for the group (i). However, all Raman parameters are the same as those of the rest samples from the group (i), indicating the immature character of OM from Lithuanian rocks. We interpret this discrepancy as representing contamination of the cores with drilling fluids, resulting in increased values for the C31 22S/(S + R) ratio. In this case, Raman spectroscopy is a useful tool for detecting extract contamination and appears to be an effective and decisive method in the case of rocks suspected of contamination.  相似文献   

16.
In many rock engineering applications such as foundations, slopes and tunnels, the intact rock properties are not actually determined by laboratory tests, due to the requirements of high quality core samples and sophisticated test equipments. Thus, predicting the rock properties by using empirical equations has been an attractive research topic relating to rock engineering practice for many years. Soft computing techniques are now being used as alternative statistical tools. In this study, artificial neural network models were developed to predict the rock properties of the intact rock, by using sound level produced during rock drilling. A database of 832 datasets, including drill bit diameter, drill bit speed, penetration rate of the drill bit and equivalent sound level (Leq) produced during drilling for input parameters, and uniaxial compressive strength (UCS), Schmidt rebound number (SRN), dry density (ρ), P-wave velocity (Vp), tensile strength (TS), modulus of elasticity (E) and percentage porosity (n) of intact rock for output, was established. The constructed models were checked using various prediction performance indices. Goodness of the fit measures revealed that recommended ANN model fitted the data as accurately as experimental results, indicating the usefulness of artificial neural networks in predicting rock properties.  相似文献   

17.
A microthermometric study of inclusions in granites and pegmatites in the Proterozoic Harney Peak Granite system identified four types of inclusions. Type 1 inclusions are mixtures of CO2 and H2O and have low salinities, on average 3.5 wt.% NaCleq; type 2 inclusions are aqueous solutions of variable salinities, from 0 to 40% wt.% NaCleq; type 3 inclusions are carbonic, dominated by CO2, with no detectable water; and type 4 inclusions consist of 20 to 100% solids, with the remaining volume occupied by a CO2-H2O fluid. Many inclusions have a secondary character; however, a primary character can be unambiguously established in several occurrences of the type 1 inclusions. These inclusions were trapped above the solidus and represent the exsolved magmatic fluid. The secondary populations of types 1, 2, and 3 probably formed as a result of reequilibration and unmixing of the type 1 fluid that progressively changed composition and density with decreasing temperature and pressure and was finally trapped along healed microfractures under subsolidus conditions. Type 4 inclusions are primary and are interpreted to be trapped, fluid-bearing, complex silicate melts that subsequently solidified or underwent other posttrapping changes.It is demonstrated that primary type 1 fluid inclusions that coexist with crystallized melt inclusions in the complex, Li-bearing Tin Mountain pegmatite were trapped along the two-fluid phase boundary in the system CO2-H2O-NaCleq. Consequently, the temperature and pressure conditions of trapping are identical to the bulk homogenization conditions—on average 340°C and 2.7 kbar. These conditions indicate that this Li-, Cs-, Rb-, P-, and B-rich pegmatite crystallized at some of the lowest known temperatures for a silicate melt in the crust. An internally consistent, empirical solvus surface in P-T-XCO2 coordinates was generated for the pseudobinary CO2-(H2O-4.3 wt.% NaCleq) pegmatite fluid system. Distribution coefficients for the major species CO2, H2O, NaCl, and CH4 between the immiscible CO2-rich and H2O-rich fluid phases as a function of pressure and temperature were extracted from data for the two cogenetic fluid inclusions types.  相似文献   

18.
This study was designed to survey the reservoir sediment properties, assess the phosphorus (P) sorption isotherm, and analyze the relationship between sediment properties and sorption parameters. Physicochemical analysis indicated that sediment from the FUSHI reservoir in Zhejiang Province, China, has similar physical and chemical properties and has been contaminated by P. Sorption isotherm experiments showed that the sorption process could be described by Langmuir and Freundlich models. The parameters of Q max (Phosphorus sorption maximum) and K (Freundlich adsorption isotherm constant) ranged from 618.98 to 825.70?mg?kg?1 and 114.18 to 170.74?l?kg?1, respectively. EPC0 (zero P equilibrium concentration) ranged from 0.14 to 0.24?mg?l?1, more than the total P concentration in the water of the reservoir. Thus, the reservoir sediment releases P into the water and acts as a ??P resource??. The clay, Feo, Alt, and Fet?+?Alt content were the main active components in P sorption. Q max had a highly significant positive relationship with some properties and could be estimated by a combination of these.  相似文献   

19.
Some of the rocks and soil-originated materials used in building construction are the serious natural radiation sources. Soil-originated bricks and roof-tiles and their raw material in the Salihli-Turgutlu area were tested in situ for natural radiation levels using a gamma-ray spectrometer. The concentrations of the radioelements 40K, 238U and 232Th and air-absorbed radiation rates were measured for soil, raw material heaps, brick and roof-tile stacks and waste brick heaps. The radium-equivalent activity Raeq of the raw material varied between 187.9 and 216.4 Bq kg?1. The external radiation hazard index Hex values ranged between 0.51 and 0.58. For building material and its products, recommended Raeq and Hex levels are 370 Bq kg-1 and 1.0, respectively. On the other hand, both Raeq and Hex values for waste brick heaps, containing broken brick pieces, coal pieces and ash, were higher than the recommended levels, i.e. Raeq values varied from 473.8 to 651.0 Bq kg-1 and Hex values were within the range 1.15–1.76. The annual dose rate and radium-equivalent activity values of the brick and roof-tiles were below the level of criteria. Annual dose rate ranged between 0.42 and 0.62 mSv y?1 and radium equivalent activity was in the range 172.9–245.2 Bq kg?1. The external and internal radiation hazard indices were all below the value of 1.0 for the Salihli-Turgutlu area bricks and roof-tiles. Results of this study were compared with results of previous studies. Natural radiation levels of construction raw material of study area are generally higher than of those of previous studies.  相似文献   

20.
洛川剖面的午城黄土是可以在野外进行细分的,洛川的午城黄土含有18层古土壤和18层黄土。其中,S15~S23的土壤组合与前人划分的WS1相当,L24与WL1相当,S24~S28与WS2相当,L29与WL2相当,S29~S32与WS3相当,L33与WL3相当。黄土高原的两个粉砂层L9和L15,虽然形成于第四纪的冷期,但并非代表了第四纪时期最为干冷的气候条件。笔者的解释是:其形成与这两个时期青藏高原及其周边山体的快速隆升导致的沙漠和黄土物源的快速增加有关。特别是1.1MaB.P.前后(L15)的隆起,使中国黄土记录对全球变化的响应显著增强,也正是在这次运动之后,中国黄土古气候记录可以与深海氧同位素很好对比,而此前的午城黄土与深海对比困难  相似文献   

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