Application of Leeb Hardness Test in Prediction of Dynamic Elastic Constants of Sedimentary and Igneous Rocks

Geotechnical and Geological Engineering - The Leeb hardness test is a non-destructive and portable technique that can be used both in the laboratory and in-field applications. The main purpose of...     

Evaluation of Carcinogenic Risk Due to Accidental Ingestion of PAHs in Contaminated Soils

Polycyclic aromatic hydrocarbons (PAHs) are types of hazardous contaminants, which their ingestion could cause severe consequences on human health. Leakages from storage tanks, underground pipelines, and evaporation ponds are the main sources of soil and groundwater contaminations at the Tehran Oil Refinery area (TOR site), located in south of Tehran, Iran. In this study, soil samples were collected from different locations at and adjacent to a polluted stream in the south of the refinery. The samples were analyzed for two hazardous PAH compounds, namely benzo[a]anthracene and acenaphthene. The clean up levels due to the accidental ingestion of contaminated soils at the site were also investigated in accordance to the U.S.EPA guidelines. Comparing the soil analysis results indicated that the benzo[a]anthracene concentrations in the samples varied from 53 to 299 mg/kg, which were higher than the clean up level of 1.17 mg/kg. Thus, soil remediation is required for this contaminant. The acenaphthene analysis results denoted that the average concentration of this contaminant was below the clean up level of 116.67 mg/kg, indicating that no treatment for this contaminant is necessary at the TOR site. Also, because the slope of the ground extends to the south of the stream, which stimulates the migration of the contaminants in this direction due to advection and dispersion mechanisms, the average of benzo[a]anthracene concentrations in south samples was higher than north samples (i.e., C_avg(S) = 160 ppm, C_avg(N) = 113 ppm). Various treatment techniques such as thermal desorption, soil vapor extraction (SVE), and solidification/stabilization (S/S) were investigated for this site. Due to moderate to high plasticity and relatively low permeability of the soil and low volatility of benzo[a]anthracene, however S/S method is recommended as a practical approach for the remediation of the soil at the site.     

江西强冻雨天气形成特征分析

使用常规气象观测资料、气候资料、NCEP 2.5°×2.5°再分析资料和自动气象站等资料,对江西50年来出现的18次持续3天10站次以上冻雨天气过程的形成特征进行分析,结果表明:(1)地面冷高压、阻塞高压、副热带高压、南支槽、850hPa切变线、地面辐合线(准静止锋)、温度锋区、700 hPa急流与湿舌等是强冻雨天气的主要影响系统,具有明显的天气系统配置特征;(2)在有利的天气形势背景下,强冻雨天气过程具有前期候(旬)增温特征.当前期平均温度极大值和平均温度值接近或超过历史同期水平时.极易出现持续性冻雨天气过程,72%以上的强冻雨天气过程与此相关;(3)18次强冻雨天气过程都存在逆温层特征,逆温层高度在850～700 hPa间,平均逆温差为4～5℃,最大10℃,同时地面温度在0℃以下或接近0℃;(4)700～850 hPa平均温差图上有3个温差中心,表明700 hPa高度上有明显的暖湿气流存在,89%的冻雨天气过程与之相关.     

Structure of the Soresat Metamorphic Complex,North Sanandaj–Sirjan Zone,northwest Iran

The metasedimentary and granitoid rocks of the Soresat Metamorphic Complex occur along the northern margin of the Sanandaj–Sirjan Zone in northwest Iran. Four different deformational events (D1–D4) are recorded in the Soresat Metamorphic Complex. The D1 and D2 progressive deformation events resulted from north-northeast–south-southwest regional horizontal shortening due to the subduction of Neo-Tethys oceanic lithosphere beneath the Sanandaj–Sirjan Zone. Post-suturing convergence between Arabia and Iran, which resulted in a right lateral-reverse displacement along the suture caused the north-northwest–south-southeast horizontal shortening of D3. D4 is recorded by normal faulting. Andalusite, cordierite and sillimanite (fibrolite) record the thermal peak (with a geothermal gradient >30°C/km). Field and microscopic studies of intruded granitoid rocks in the Soresat Metamorphic Complex divide them into three major groups: (i) syn-deformation (syn-D2) granitic gneiss; (ii) late- to post-deformation (late- to post-D2) granites and granodiorites; and (iii) post-deformation (post-D2) alkali granites.     

Intermediate sulfidation epithermal Pb-Zn-Cu (±Ag-Au) mineralization at Cheshmeh Hafez deposit, Semnan province, Iran

The Cheshmeh Hafez epithermal base metal deposit is located in Troud-Chah Shirin mountain range in the Alborz magmatic belt of northern Iran. In this area, the Eocene volcanism and associated mineralization are controlled by NW-SE trending Anjilo and Troud major faults. Geological units are composed of porphyritic andesite, andesitic basalt, dacite, rhyodacite, trachyandesite and basalt, which are typically high-K igneous rocks transitional to shoshonites. Alteration in Cheshmeh Hafez area comprise of propylilitization, sericitization, argillization and silicification. Mineralization consists of three stages. Stage 1, quartz, carbonate with early pyrite I and chalcopyrite assemblages. Stage 2, the main stage of sulfide deposition, comprises early euhedral galena I followed by galena II and sphalerite, then galena III, chalcopyrite, tetrahedrite, pyrite II, bornite and digenite. Stage 3 involves the deposition of quartz and calcite barren veins with minor pyrite. The average assays from 12 channel samples of Cheshmeh Hafez veins are 0.15 g/t Au, 3.23 g/t Ag, 4.47 wt % Pb, 2.64 wt % Cu, and 1.73 wt % Zn. Fluid inclusion homogenization temperatures (Th) in quartz fall within the range of 140°-280°C with salinities ranging from 4.7 to 18 wt. % NaCl equivalent. Comparison of Th versus ice melting (Tm_ice) values indicates fluid dilution.     

Compressibility of calcium ferrite-type MgAl2O4

 In situ X-ray diffraction experiments of calcium ferrite-type MgAl₂O₄ have been carried out using a diamond anvil cell combined with synchrotron radiation and an imaging plate X-ray detector under hydrostatic pressures up to 9 GPa. The observed unit-cell volumes at various pressures were fitted to the Birch-Murnaghan equation of state, yielding a bulk modulus of K _{T 0}= 241(3) GPa when K′ _{T 0}=4 is assumed. This relatively large bulk modulus of calcium ferrite-type MgAl₂O₄ is consistent with that expected from the systematic relation between bulk modulus and molar volume for the most compounds possessing fcc oxygen packing. Received March 5, 1996/Revised, accepted October 15, 1996     

Rate of coastal transport along the southeastern mediterranean coast during storms using water hyacinth

The current study provides a potential method for measuring current velocities during storms. Water hyacinth debris, carried from the Nile outlet area by the offshore current, are washed ashore along the Israeli coasts after southwesterly winter storms. The impact of the offshore current and wind on the floating debris is such that storms of five days duration are sufficient to transport plants from the Nile to the Carmel coast, a distance of about 400 km. The available information indicates a high rate of transport in the southeastern Mediterranean.     

Generation of isoprenoid compounds,notably prist-1-ene,via photo- and autoxidative degradation of vitamin E

In order to mimic the photodegradation of vitamin E during phytoplankton senescence and study the behaviour of the resulting photoproducts during cell lysis, vitamin E dispersed in seawater was irradiated with solar light in the presence of hematoporphyrin as sensitizer. Under these conditions, singlet oxygen-mediated photooxidation and free radical oxidation (autoxidation) acted simultaneously on the substrate, affording 4,8,12-trimethyltridecanal, 4,8,12-trimethyltridecanoic acid, 6,10,14-trimethylpentadecan-2-one, α-tocopherylquinone, 4,8,12,16-tetramethylheptadecan-4-olide, 2,3-epoxy-α-tocopherylquinone and 5,6-epoxy-α-tocopherylquinone as minor products. Different mechanisms were proposed to explain the formation of these different isoprenoids. The main products (85% of the degraded substrate) appeared to be previously described diastereoisomeric trimeric oxidation products of vitamin E, whose pyrolysis during gas chromatography–mass spectrometry (GC–MS) afforded 2,6,10,14-tetramethylpentadec-1-ene (prist-1-ene). On the basis of their greater ability to produce prist-1-ene during pyrolysis than intact vitamin E and their highly favoured production in phytoplanktonic cells, these trimers are proposed as likely sources of this isoprenoid alkene, previously identified in many pyrolysates from immature kerogens.