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Search Results: 1 - 10 of 147 matches for " Sands "
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Preliminary Geophysical Investigation to Delineate the Groundwater Conductive Zones in the Coastal Region of Akwa Ibom State, Southern Nigeria, around the Gulf of Guinea  [PDF]
George N. Jimmy, Akpan A. Otu, Umoh A. Asuquo
International Journal of Geosciences (IJG) , 2013, DOI: 10.4236/ijg.2013.41011
Abstract:

This paper presents the first work of its kind within the confines of the study area. It unravels the distribution of the layers of conductive sand and their depths of interaction between freshwater from fresh sands and saltwater within the conductive layers in the coastal region of Akwa Ibom State (Nigeria) around the Gulf of Guinea. Vertical electrical sounding (VES) data whose fidelity was achieved by constraining the data by the available nearby logged borehole information during interpretation was the method applied. In the western region of the study area, the ferruginized and saline water layer is found within the depth range of 22 to 75 m deep. In the northern zone, conductive sandy layer is found within 50 to 210 m and in the eastern zone, the saline and ferruginized sandy layer is found within the depth of 88.5 m and above. Generally, the horizontal and vertical cross sections of the subsoil and the flow regime from water table depths have been delineated. With these information, water can be tapped in the area with caution and the flow direction determined can be used as input parameter in detailed contamination study.

The Study of Green Compression Strength of a Green Sand Mould Using Statistical Approach  [PDF]
Aondona Paul Ihom, Aniekan Offiong
Materials Sciences and Applications (MSA) , 2014, DOI: 10.4236/msa.2014.512089
Abstract: The study of green compression strength of a green sand mould using statistical approach has been undertaken. Empirically generated data in National Metallurgical Development Centre, Jos Sand Testing Laboratory were used for the study. Coefficient of correlation, coefficients of determination and coefficient of multiple determinations were used to explain the relationship existing between the two independent variables of clay and moisture content and green compression strength, the dependent variable. The study showed that the coefficient of determination for Ys: X1 was 0.88 while the coefficient of correlation was 0.94, coefficient of determination for Ys: X2 was 0.90 while the coefficient of correlation was 0.95 and the coefficient of multiple determination was 0.72; these coefficients assisted tremendously in the study of green compression strength. A mathematical model was developed for the prediction of green compression strength; it was tested and proved to be a good estimation tool for estimating green compression strength values on the foundry shop floor. The study has clearly shown that statistical approach is a good tool for studying green compression strength of green sand moulds.
Removal of Pb(II) from Aqueous Solutions by Zeolites, Porcelanite and Sands: Correlation of Morphology and Chemical Composition to Batch Removal Efficiency  [PDF]
Fawwaz Jumean, Lucia Pappalardo, Hani Khoury
American Journal of Analytical Chemistry (AJAC) , 2015, DOI: 10.4236/ajac.2015.64028
Abstract: Chemical compositions of natural zeolites, porcelanite (opal-CT) and local sands were determined by X-ray fluorescence (XRF) and correlated with their Pb(II) removal efficiencies. Zeolites and porcelanite were from the Mikawer, Aritain and Hannon areas in Jordan. Sands (white, red and yellow) were from the United Arab Emirates (UAE). The effect of Pb(II) concentration and zeolite dosage on removal efficiency was investigated at 25.0°C using the batch equilibrium method. Commercial kaolinite, silica and alumina were also studied for comparison. Removal efficiencies, in mg Pb(II)/g adsorbent, were: 76.9, 52.7 and 42.1 for Hannon, Mikawer and Aritain zeolites, respectively; 58.2 for porcelanite; 29.7, 11.0 and 8.5 for yellow, red and white sand, respectively; 7.2, 3.3 and 1.3 for kaolinite, silica and alumina, respectively. XRF data indicate that adsorbents with intermediate molar ratios of Si/Al, in the range 2.70 - 2.93, are most efficient in Pb(II) removal. Scanning electron microscope (SEM) images of adsorbents suggest that morphology, in addition to chemical composition, plays a key role. In particular, a combination of factors, including shapes and sizes of crystals, channels in zeolites and pores in porcelanite, appear to favor removal of Pb(II).
The Reduction in the Swelling Potential of the Foundation Ground of Togblécopé in Togo by the Stabilization with Binders and Sands  [PDF]
Kossi Bolanigni Amey, Komi Mawutodzi Sounsah, Komla A. S. Amoussou, Koumah Neglo
Open Journal of Civil Engineering (OJCE) , 2018, DOI: 10.4236/ojce.2018.82017
Abstract: The present study aims at helping to search for preventive solutions to pathologies of constructions in Togblécopé in Togo, by the reduction in the withdrawal and swelling of foundation grounds through their stabilization. Togblécopé’s clay taken from 1 m, 2 m and 3 m deep, and mixed with four binding materials (cement, sea sand, silty sand and lime). Tests of identification and free swelling with odometer are carried out on pure and stabilized materials. What emerges from these tests is that the limits of liquidity and plasticity are rising along with the rate of stabilizers while the index of plasticity is falling. Cement and lime cause a reduction in the index value of plasticity by almost 50%. The more the sand’s grain size, the more the reduction in the plasticity index. The swelling potential is reduced by 60% for cement and lime, 30% for sea sand and 20% for silty sand. The present study is a contribution to the reduction in deflations from 20% to 60% of some parts of constructions in order to limit cracks.
Mineralogical Characterization of Aeolian Sands from Inner Mongolia, China  [PDF]
Brian Nzuki, Liqun Luo, Pengfei Zhou, Christophe Niyonzima, Xu Tu
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2019, DOI: 10.4236/jmmce.2019.73007
Abstract: Aeolian sand sample from Tengger desert, located in the southern part of Inner Mongolia (China) was characterized for major elemental composition and mineralogy by EPMA, XRF and XRD methods. The objective of this research was to provide data which would be a guide to aid future beneficiation of this sand, especially for the economic exploitation of feldspar and quartz which have a wide range of applications in various industries like plastic, paint, ceramics and glass industries. The elemental analysis of the sample was carried out by X-ray fluorescence spectrometer and chemical analysis while the minerals present were identified by an X-ray diffraction analyzer. The sand was discovered to contain basically SiO2 (82.43%), Al2O3 (7.68%), Na2O + K2O (4.37%) and TiO2 and Fe2O3 as the main impurities. It was also discovered that grinding of the sand is required to enhance the liberation of the minerals and the separation methods recommended are magnetic separation and flotation. It was therefore concluded that aeolian sand is a suitable source of quartz and feldspar for use in the industry.
Arena como dosímetro termoluminiscente para dosis terapéuticas
Ricaurte,Daniel; Salcedo,Juana; Cogollo,Rafael;
Ingeniería y Ciencia , 2010,
Abstract: this work describes the characteristic thermoluminiscent of sand coming from cove?as beaches, for its use as therapeutic dose dosimeter. the selected samples, annealed at 400°c during 1 hour, were irradiated to different doses using an unit of 60co theratron 780c in air to ambient temperature. the reading was carried out in a harshaw tld 4500. the main dosimetric properties of the material (glow curve, response reproducibility, reutilization, linearity and thermal decay) have been studied in detail. the glow curve of the sand samples presents a peaks tl at about 145°c. the results show that the material has a linear response to the dose from 50 cgy until 1000 cgy. the studied sand samples can be used as thermoluminescent dosimeters for applications in different areas. the importance of this work is that the sand is a natural substance available in large quantities, low cost and can be used in clinical physics to evaluate the dose received by the patient during medical treatment.
The diffusion of sulphur from moulding sand to cast and methods of its elimination
M. Hosadyna,ST. M. Dobosz,P. Jelinek
Archives of Foundry Engineering , 2009,
Abstract: The care of high quality castings requires taking into account the possible negative influence of decomposition products of moulding and core sands on the structure of castings produced. Such products are emitted both from the sands of I generation, meaning sands bound by bentonite, especially those containing carbon forming additives, as well as from the sands of II generation, meaning the sands with the binding materials or even the sands without any binders, such as the forms produced by using the LOST FOAM technology. The literature often refers to the negative effects of nitrogen emitted from the sands with the urea resins on the tendency to create surface defects. That is why the aim of this study was to assess the degree of sulphur diffusion to the ferroalloy castings and the proposal of its limitation.
Evolution of technogenic landscapes by the example of apatite-nepheline ore concentration wastes  [PDF]
Vladimir N. Pereverzev, Galina A. Evdokimova, Irina V. Zenkova, Maria V. Korneykova, Vera V. Redkina
Natural Science (NS) , 2010, DOI: 10.4236/ns.2010.26075
Abstract: A primary soil-forming process can take place on the concentration waste of apatite-nepheline ores, whose biological recultivation was carried out more than 40 years ago. This process is characterized by the following features: forming of a thin litter with the content of organic carbon at the level of 8-12%, accumulation of humic substances in the sub-litter layer and the change of рН values. Microorganisms are biocatalysts of primary soil formation processes and one of the main factors that determine the specificity of this process. The prokaryotic complex of the newly formed soils, generated from nepheline sands, is considerably different from that of zonal soils on moraine sediments. The former ones are dominated by gram-positive bacteria, mainly actinobacteria, as well as by their filamentous forms (actinomycetes), whereas the latter ones are dominated by gram-negative bacteria. A common feature of invertebrate’s complexes in nepheline sands is the low species diversity, small-size and quickly development of microfauna and mesofauna representatives and the dependence of succession of microarthropods pioneer groups on the succession of bacteria and fungi.
Bayesian Data Fusion (BDF) of Monitoring Data with a Statistical Groundwater Contamination Model to Map Groundwater Quality at the Regional Scale  [PDF]
Samuel Mattern, Walid Raouafi, Patrick Bogaert, Dominique Fasbender, Marnik Vanclooster
Journal of Water Resource and Protection (JWARP) , 2012, DOI: 10.4236/jwarp.2012.411109
Abstract: Groundwater contamination by nitrate within an unconfined sandy aquifer was mapped using a Bayesian Data Fusion (BDF) framework. Groundwater monitoring data was therefore combined with a statistical groundwater contamination model. In a first step, nitrate concentrations, measured at 99 monitoring stations irregularly distributed within the study area, were spatialized using ordinary kriging. Secondly, a statistical regression tree model of nitrate contamination in groundwater was constructed using land use, depth to the water table, altitude and slope as predictor variables. This allowed the construction of a regression tree based contamination map. In a third step, BDF was used to combine optimally the kriged nitrate contamination map with the regression tree based model into one single map, thereby weighing the kriged and regression tree based contamination maps in terms of their estimation uncertainty. It is shown that BDF allows integrating different sources of information about contamination in a final map, allowing quantifying the expected value and variance of the nitrate contamination estimation. It is also shown that the uncertainty in the final map is smaller than the uncertainty from the kriged or regression tree based contamination map.
Comparative Study of Gold Concentration by Elutriation from Different Precious Metal Bearing Ores  [PDF]
Martín A. Encinas-Romero, Guillermo Tiburcio-Munive, Jesús L. Valenzuela-García
International Journal of Nonferrous Metallurgy (IJNM) , 2013, DOI: 10.4236/ijnm.2013.24018
Abstract:

Conventional methods for precious metals gravimetric concentration involve equipment such as shaking tables, centrifuging concentrators, jigs, trommels, or a combination of those. A less commonly used technique is elutriation, which represents an efficient, safe and low-cost method of separation. The goal of the present investigation was to make a comparative study of gold concentration by elutriation from different precious metal bearing ores: an oxide ore, a mineral consisting of a sulfide matrix, a mineral in which the precious metals are free and disseminated and a slimy and clayey black sand material. The best recoveries of precious metals by elutriation were attained for the free disseminated ore and for the black sands, obtaining gold recoveries of 70% and 96% respectively, with appreciable ratios of concentration as well.

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