ISSN / EISSN : 2161-7538 / 2161-7546
Current Publisher: Scientific Research Publishing, Inc. (10.4236)
Total articles ≅ 110
Latest articles in this journal
Geomaterials, Volume 11, pp 1-21; doi:10.4236/gm.2021.111001
The Gabal (G.) El-Niteishat area lies in the Central Eastern Desert of Egypt which is known for various mineral resources and geological structures. Umm Gheig, Umm Naggat, Umm Shaddad, Wadi (W.) Zeidun and Sigdit represent some important regions that contain mineral deposits in the study area. Various filters such as first vertical derivative (FVD), horizontal gradient magnitude (HGM), tilt derivative (TDR) and near-surface were applied to the airborne magnetic data for the study area to deduce the structural lineaments and magnetic source edges which were controlled by the presence of mineral deposits. Processed Landsat ETM+ images are used for delineating the rock unit boundaries that are exposed in the study area such as serpentinite, metagabbro, metavolcanics and metasediments. Also, band ratios, principal component analysis (PCA) and false-color composite image (Crosta alteration image) were applied to get specific results about the alteration zones. The structural lineaments analysis illustrated that the common trends that affected the study area were NW-SE, NE-SW, E-W and N-S. Integration of remote sensing and airborne magnetic data exhibited the relation between mineralization and structural lineaments.
Geomaterials, Volume 10, pp 105-117; doi:10.4236/gm.2020.104007
Kom Ombo temple is one of temples which were belted over high plateau close to the River Nile, near to Aswan in Egypt in the Greek-Roman period. The expected archaeological remains in the selected area are the hidden tunnels of the mummified crocodiles. The aim of the present work is to detect any of these tunnels by the application of the (GPR) and (SP) methods. The interpretation of the 10 GPR profiles revealed some locations of possible hidden tunnels. These locations show different contrasts and high amplitudes of the reflected signals, compared to the enclosing soil; also the scattering of the signals is higher than the bed layer in these locations, which may reveal the possible buried mummified crocodile tunnels in the study area. The depths of the possible targets range from 2.0 m to 2.5 m. The SP electric map shows that the study area possesses a range of about 135 mV of the potential differences between the measured stations. The positive response of the SP data is mainly concentrated at the central part of the study area. The relatively weak, negative SP anomalies may be related to moisture in the soil. The positive SP anomalies on the SP electric map display possible significant correlation between them and the inferred tunnel locations from the GPR data. The calculated depths from the SP profiles show significant agreement with that estimated from GPR data depths, which indicate that the SP electric method can be used as a successful tool in detecting buried archaeological remains in support of GPR.
Geomaterials, Volume 10, pp 56-65; doi:10.4236/gm.2020.103004
Raw rubber Latex contents, from 0% to 30% were used to stabilize lateritic samples to provide an alternative to cement stabilization. These samples were submitted to physical tests (water resistance test, absorption test) and mechanical tests (dry compressive strength test). The results indicate that samples made of latex content less than 15% dissolve completely into water. So it was impossible to make sample with these contents. Samples with 15% of raw rubber content or more are steady after water resistance test. The absorption rate of these samples decreases as the latex content increases. It goes from 14.45% for the samples at 15% to 5.87% for those at 30%. Therefore, the compressive strength test indicates that the resistance increases from 0.37 MPa for samples without latex to 3.15 MPa for those at 30% of latex content. Also, the rheological study shows that the samples pass from a brittle behaviour to a plastic behaviour when the latex content increases. The behaviour of the sample according to these different tests shows that this material can be used in several activity areas, such as construction, road building and sports area.
Geomaterials, Volume 10, pp 25-34; doi:10.4236/gm.2020.102002
Geomaterials, Volume 10, pp 35-55; doi:10.4236/gm.2020.103003
Geomaterials, Volume 10, pp 91-104; doi:10.4236/gm.2020.104006
Rock mechanics projects, excavations and rock mass monitoring are day-by-day concerns of professionals and scientists of rock engineer. Technological advances observed in the 20 and 21 centuries provided high precision equipment capable of establishing deformation and estimating the rock mass stress remotely and in real time. In addition, in order to confirm and study the data obtained with theses equipment, numerical programs of modeling became more accessible to schools, research centers and private companies. Monitoring an excavation requires, besides understanding fully the rock structure, precise definitions and goals: why, how, where. This article discusses concepts of monitoring, modeling and calibration, as well as presents examples of applications where these questions were successfully answered.
Geomaterials, Volume 10, pp 66-90; doi:10.4236/gm.2020.103005
It is shown that the ore-forming systems (OFS) of the Vendian-Riphean Greenstone belts (GSB) in the Transbaikalia region were formed in a wide age range: from the Riphean to the Cenozoic. They are grouped into 6 metallogenic types. The noble metal type is divided into 6 metallogenic subtypes differed in time duration intervals of functioning. OFS evolution wore multistage nature inherited from the composition of the GSB primary rocks, with a tendency of the ore generating processes remobilization and regeneration (dynamometamorphism) changing over time by rejuvenation (shoshonite latite and picrobasalt magmatism, mud volcanism).
Geomaterials, Volume 10, pp 1-23; doi:10.4236/gm.2020.101001
The new results of geologic-structural, petrographic and mineralogic-geochemical researches of Mykert-Sanzheevka ore field—the Uda-Vitim mineragenic zone South-West ending of West Transbaikalia are given. Its main ore-controlling structure, represented by losange, consisting of rhombohedral and tetrahedral blocks-duplexes mosaic clusters, which are separated by narrow tectonic sutures, is specified. It is clarified that polycomponent ores clusters are confined with these small-block sutures, made by subvolcanic dykes of shoshonite-latite volcano-plutonic association (233 - 188 million years), apodyke dynamometamorphites (breccias, cataclasite, mylonites) and also mechanometasomatites. Four stages of the dynamometamorphites formation characterized by different species compositions of ore minerals appeared as a result of mechanochemical reactions are determined. A carbonyl model of mineral microaggregates formation with films containing noble metal nanoparticles is proposed. Ore-forming system features of Mykert-Sanzheevka field are considered.
Geomaterials, Volume 9, pp 40-53; doi:10.4236/gm.2019.91004
Earth bricks could contribute to alleviate the housing shortage in the world, thanks to their low cost, easy production, and low environmental impact. However, to manufacture bricks with required properties, many raw soils must be ameliorated. In Central and Eastern Africa, the waste water of the cassava processing is used to improve earth brick mechanical properties. This technique is interesting, because it is sustainable, low-cost and easy to implement. But, studies on this stabilization method are scarce, in particular on the drying kinetics of these bricks. Now, it is important to know the drying duration, because the earth brick’s strength is strongly correlated to its moisture content. Thus, this study aims to quantify and to model the effect of adding cassava flour gel and amylopectin on the drying kinetics of earth bricks. Depending on the soil nature, the drying duration decreases from 7% to 25% for a stabilizer content of 20%. For the five models used, the coefficient of determination is superior to 0.997 and the chi square is inferior to 3 × 10−4. In average, the best model is Khazaei, followed in order by Avrami-Page, diffusion, Yong and Peleg. The effective coefficient of diffusion of water is about 4 × 10−5 m⋅s−2. The parameter T of the Khazaei’s model is strongly correlated to the drying duration and the stabilizer content, and their relationships have been deduced.
Geomaterials, Volume 9, pp 29-39; doi:10.4236/gm.2019.91003
The agate dyeing industry has been commonly seen as a high-pollution industry. Dyeing wastewater treatment is considered one of the most important categories for water-pollution control, because of its intense colour and the high concentration of organic contaminants. Most dyes used in the process present minimal biodegradability due to aromatic organic compounds in their structure. Using a photocatalytic reactor, experiments were carried out to study the decolorization of a water solution containing 8% ethylic alcohol and 200 mg L−1 of the dye Rhodamine B (RhB), the most difficult colorant to degrade among the used by the agate industry. The best conditions were further applied to treat the same agate water/ethyl alcohol solution containing a mixture of 200 mg L−1 of Rhodamine B (RhB), Crystal Violet (CV), Brilliant Green (BG), and Blood Red (BR). All the experiments were performed in a 2 L reactor equipped with ultraviolet (UV) lamps, at a wavelength of 365 nm, with powdered TiO2 or ZnO as the catalyst. The results indicated that the optimal decolorization conditions were attained with 2.5 g L−1 of the catalyst at pH 10 and an irradiation time of 80 min. The process resulted in complete degradation of CV, BG and 80% - 90% degradation of RhB and BR. The catalyst ZnO presented a performance somewhat better than TiO2. It is possible to conclude that the process of heterogeneous photocatalysis is effective for decolorization of water streams from the agate industry.