Higher dimensional inhomogeneous cosmological models in Lyra geometry

We have presented in homogeneous cosmological models within the framework of Lyra geometry. We have considered an inhomogeneous spherically symmetric higher dimensional model in presence of a mass less scalar field whose potential has a flat part. The scalar field is considered to be inhomogeneous. Also an inhomogeneous cosmological model is derived in a Kaluza-Klein type of space time. The matter field is taken as an inhomogeneous distribution of fluid. It is observed that there is no singularity at finite past in our model and the desirable feature of dimensional reduction is also possible for the extra space. This revised version was published online in July 2006 with corrections to the Cover Date.     

Mobility and impact of trace metals in Barapukuria coal mining area, Northwest Bangladesh

Trace metals were analyzed in water and sediment samples from Barapukuria coal mine area of Bangladesh in order to evaluate their mobility and possible environment consequences. Cadmium is the most mobile element with an average partition coefficient (log K _d ) of 2.95 L/kg, while V is the least mobile element with a mean log K _d of 5.50 L/kg, and their order of increasing mobility is: V < As < Pb < Fe < Cr < Se < Mn < Ni < Zn < Cu < Ba < Sr < Cd. Contents of organic carbon in sediment samples shows strong positive correlations with most trace metals as revealed by the multivariate geostatistical analysis. The overall variation in concentration is mainly attributed to the discharge of effluents originating from the coal mining activities around the study area. Compared to their background, Ni and Cu are the most enriched while significant enrichment of As, Mn, Ba, Sr, Cr, and Pb is also observed in the sediments. Geoaccumulation indices (I _geo ) suggest sediments are moderately to heavily polluted with respect to Ni and Cu. The metal pollution index (MPI) varied from 91.91 to 212.01 and the highest value is found at site CM03 that is close to discharge point. The sediment quality guideline index (SQG-I _Intervention ) values (0.56–1.52) suggest that the sediments at the study area have moderate to high ecotoxicological risk.     

Hawking non-thermal and thermal radiations of Reissner Nordström anti-de Sitter black hole by Hamilton-Jacobi method

We have investigated Hawking non-thermal and purely thermal Radiations of Reissner Nordström anti-de Sitter (RNAdS) black hole by massive particles tunneling method. The spacetime background has taken as dynamical, incorporate the self-gravitation effect of the emitted particles the imaginary part of the action has derived from Hamilton-Jacobi equation. We have supposed that energy and angular momentum are conserved and have shown that the non-thermal and thermal tunneling rates are related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum. The results for RNAdS black hole is also in the same manner with Parikh and Wilczek’s opinion and explored the new result for Hawking radiation of RNAdS black hole.     

A simple and inexpensive method for muddy shore profiling

There are several well-established methods for obtaining beach profiles, and more accurate and precise high-tech methods are emerging. Traditional low-cost methods requiring minimal user skill or training are still popular among professionals, scientists, and coastal zone management practitioners. Simple methods are being developed with a primary focus on sand and gravel beaches. This paper describes a simple, low-cost, manual field method for measuring profiles of beaches, which is particularly suitable for muddy shores. The equipment is a type of flexible U-tube manometer that uses liquid columns in vertical tubes to measure differences in elevation; the supporting frame is constructed from wooden poles with base disks, which hold measuring scales and a PVC tube. The structure was trialed on a mudflat characterized by a 20~0-cm-thick surface layer of silt and clay, located at the Kutubdia Island, Bangladesh. The study results are discussed with notes on the method＇s applicability, advantages and limitations, and several optional modifications for different scenarios for routine profiling of muddy shores. The equipment can be used by one person or two people, and the accuracy of the method is comparable to those in other methods. The equipment can also be used on sandy or gravel beaches.     

Uptake and Accumulation of Arsenic in Different Organs of Carrot Irrigated with As‐Rich Water

Irrigation with arsenic (As)‐rich water in agricultural soil may increase high levels of As in crops and cause food chain contamination. In this study, a greenhouse experiment was established using Spanish agricultural soil (Valladolid and Segovia provinces), that are extensively cultivated for carrot plant, to investigate the process of As uptake, bioaccumulation, and translocation of As from root to shoot and leaves in carrot plant. Arsenic concentrations in different organs of carrot plant, rhizosphere soil, and soil solutions were determined by hydride generation atomic absorption spectrometry (AAS). High concentrations of As in irrigation water, and the alkaline and sandy character of this soil enhanced As uptake in carrot plants indicating the potential health risk from consumption of carrots cultivated in these areas. Bioaccumulation of As into the leaves and roots increased with increase of As concentration in irrigation water. Both roots and leaves demonstrated a higher accumulation rate of As at an As concentration of 41 than 131 µg L^?1 in the soil solution. The ratios of As_root/As_leaves showed no statistically significant differences for the different irrigation treatments, and had an average value of 0.36 indicating the high magnitude of As translocation from roots to leaves in carrot plants. The leaves of carrots had a higher affinity for As than roots did. The correlation between As uptake by leaves or roots of carrots and the soluble As in rhizosphere soil did not demonstrate a linear or a plateau curve, indicating a slow but continuous constant As absorption which could be prolonged over time with high potential environmental risks.     

Comparison of ordinary kriging and artificial neural network for spatial mapping of arsenic contamination of groundwater

In this technical note, we investigate the hypothesis that ‘non-linearity matters in the spatial mapping of complex patterns of groundwater arsenic contamination’. The spatial mapping pertained to data-driven techniques of spatial interpolation based on sampling data at finite locations. Using the well known example of extensive groundwater contamination by arsenic in Bangladesh, we find that the use of a highly non-linear pattern learning technique in the form of an artificial neural network (ANN) can yield more accurate results under the same set of constraints when compared to the ordinary kriging method. One ANN and a variogram model were used to represent the spatial structure of arsenic contamination for the whole country. The probability for successful detection of a well as safe or unsafe was found to be atleast 15% larger than that by kriging under the country-wide scenario. The probability of false hopes, which is a serious issue in public health monitoring was found to be significantly lower (by more than 10%) than that by kriging.     

Characterization and advanced oxidation treatment of dyeing effluent by Fenton’s reagent

Textile effluent from dyeing process has been a serious environmental threat for years. This study was intended to evaluate the performance of Fenton’s process for the removal of chemical oxygen demand (COD), colour and turbidity. Experiments were conducted by laboratory-scale reactors fed with cotton dyeing effluent. The Fenton process employs ferrous ions and hydrogen peroxide H₂O₂ under acidic pH conditions. The experimental variables studied include doses of iron salts and hydrogen peroxide, oxidation time, pH for oxidation and coagulation. The COD, color and turbidity removal reached a maximum of 97.2, 96.8 and 84.8% respectively at a reaction time of 20 min under optimum doses of H₂O₂ and Fe²⁺. Hydrogen peroxide dose ranging from 0.5 to 2.0 mL/500 mL and FeSO₄ · 7H₂O in the range of 0.5–4.0 gm/500 mL were selected to be examined at different reaction times between 10 and 30 min. Optimum dose of hydrogen peroxide and ferrous sulphate were 2.0 mL and 1.0 gm respectively for 500 mL of sample. In this study optimized pH 4.0 and 6.0 was found effective for oxidation and coagulation respectively.     

Mineral potential mapping in Central Iran using fuzzy ordered weighted averaging method

The aim of this work is to introduce the application of the fuzzy ordered weighted averaging method as a straightforward knowledge‐driven approach to explore porphyry copper deposits in an airborne prospect. In this paper, the proposed method is applied to airborne geophysical (potassium radiometry, magnetometry, and frequency‐domain electromagnetic) data, geological layers (fault and host rock zones), and various extracted alteration layers from remote sensing images. The central Iranian volcanic–sedimentary belt in Kerman province of Iran that is located within the Urumieh–Dokhtar (Sahand–Bazman) magmatic arc is chosen for this study. This region has high potential of mineral occurrences, especially porphyry copper, containing some active world‐class copper mines such as Sarcheshmeh. Two evidential layers, including the downward continued map and the analytic signal of such filtered magnetic data, are generated to be used as geophysical plausible traces of porphyry copper occurrences. The low values of the resistivity layer acquired from airborne frequency‐domain electromagnetic data are also used as an electrical criterion in this study. Four remote sensing evidential layers, including argillic, phyllic, propylitic, and hydroxyl alterations, are extracted from Advanced Spaceborne Thermal Emission and Reflection Radiometer images in order to map the altered areas associated with porphyry copper deposits. The Enhanced Thematic Mapper plus images are used to map iron oxide layer. Since potassium alteration is the mainstay of copper alteration, the airborne potassium radiometry data are used. Here, the fuzzy ordered weighted averaging method uses a wide range of decision strategies in order to generate numerous mineral potential/prospectivity maps. The final mineral potential map based upon desired geo‐data set indicates adequately matching of high‐potential zones with previous working mines and copper deposits.     

海洋沉积土动剪切模量与阻尼比的试验研究

动剪切模量和阻尼比是工程场地地震安全性评价及地基动力反应分析的重要动力学参数。为评价某海域海洋土的动力学特性,对10.3～84.2 m深度范围内的海底淤泥质粉质黏土、粉砂及细砂开展共振柱试验。利用双对数模型建立了最大动剪切模量随上覆压力的递增关系。研究发现,现有规范的剪切模量比与阻尼比的推荐取值并不适用于海洋沉积土,即使考虑借鉴以往研究成果也必须将其限制在一定的应变范围,并应考虑土体的天然应力状态取值。利用马丁-达维登科夫（Martin- Davidenkov）模型及阻尼比与剪应变的经验关系建立了剪切模量比和阻尼比随剪应变的变化规律,并由此提出了适用于海洋沉积土的5×10-6～10-3应变范围内剪切模量比及阻尼比的推荐值。研究成果可为海洋工程场地的设计、施工及抗震分析提供技术参考依据。     

A numerical investigation of rock pillar failure mechanism in underground openings

The study of rock pillar failure mechanisms is an issue that is faced routinely in mining and civil industries. In mining operation, the establishment of several mining levels is often necessary to ensure adequate production. This result in the formation of pillars that must be recovered under often high stress conditions at later stages of excavation. It is, therefore, beneficial to develop guidelines that can be used in the design of rock pillars. The aim of this paper is to delve into the mechanisms involved in pillar failure as well as to investigate the non-linear behavior of rock pillars. An extensive numerical analysis was carried out to study the pillar deformation and failure process under natural loading conditions. Effects of pillar geometry and pillar strength parameters on pillar behavior were investigated for hard rock material typical of Canadian mining conditions. Numerical data were compared against field data recorded in Canadian mines. A fairly good match was achieved between numerical and field data and the conducted analysis can be used as a qualitative guideline in the design of rock pillars in underground structures.