A simple apparatus to study the effect of lithology,permeability, and wettability on spontaneous imbibition     

Omar A. Almisned  Abdulrahman A. Alquraishi  Khalaf A. Al-Otaibi 《Arabian Journal of Geosciences》2018,11(10):235

The spontaneous imbibition phenomenon is an important process in hydrocarbon recovery. Laboratory study of imbibition is affected by many parameters including, rock characteristics, boundary conditions, length of the sample, variable interfacial tension, and sample heterogeneity. Investigating spontaneous imbibition enhances our understanding of the imbibition mechanism and, hence, helps improve waterflooding used in the oil industry. A simple apparatus has been developed to resemble naturally fractured reservoirs. Using the developed apparatus, the effects of lithology, permeability, and wettability on spontaneous imbibition have been experimentally investigated. Some encountered unexpected technical problems during the experiments are overcome and reported in this paper. Details of the developed apparatus are shown and spontaneous imbibition results are presented. First, the effect of permeability on the oil recovery rate is presented. In addition, obtained curves of oil recovery by water spontaneous imbibition using different lithology are presented. Finally, results of oil recovery from Berea sandstone core sample before and after wettability alteration are shown.  相似文献   

Estimating of water erosion in semiarid regions using RUSLE equation under GIS environment   总被引：1，自引：0，他引：1  

Omar Djoukbala  Mohamed Mazour  Mahmoud Hasbaia  Oussama Benselama 《Environmental Earth Sciences》2018,77(9):345

Water erosion is one of the main forms of land degradation in Algeria, with a serious repercussion on agricultural productivity. The purpose of this study is to estimate the soil loss of Wadi El-Ham watershed in the center of Algeria, this study aims also to evaluate the effectiveness and reliability of the use of the Revised Universal Soil Loss Equation (RUSLE) under a Geographic Information System in this field. The RUSLE model involves the main factors of erosion phenomena, namely, rain aggressiveness, soil erodibility, topographic factor, land cover index and the anti-erosive practices factor. Using this approach, the specific erosion in Wadi El-Ham watershed is estimated as 5.7 (t/ha/yr) in the entire watershed area. This result is compared to the measured suspended sediment at the Rocade-Sud gauging station situated outlet the watershed. These data consist of 1293 instantaneous measures of the water discharge and the suspended sediment concentration recorded during 21 years. Through this comparison, the used approach of RUSLE under GIS estimates the soil loss in Wadi El-Ham in Hodna region of Algeria with an error of 7.5%. Consequently, the results obtained in cartographic format make it possible to target the areas requiring priority action for a larger scale analysis to find appropriate solutions to combat erosion and to protect the natural environment.  相似文献   

Correction to: Accurate Ocean Bottom Seismometer Positioning Method Inspired by Multilateration Technique     

Omar Benazzouz  Luis M. Pinheiro  Luis M. A. Matias  Alexandra Afilhado  Daniel Herold  Seth S. Haines 《Mathematical Geosciences》2018,50(5):607-607

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Perspectives for Distributed Observations of Near-Earth Space Using a Russian–Cuban Observatory     

D. V. Bisikalo  I. S. Savanov  S. A. Naroenkov  M. A. Nalivkin  A. S. Shugarov  N. S. Bakhtigaraev  P. A. Levkina  M. A. Ibragimov  E. Yu. Kil’pio  M. E. Sachkov  A. P. Kartashova  A. M. Fateeva  Marta R. Rodriguez Uratsuka  Ramses Zaldivar Estrada  Antonio Alonsa Diaz  Omar Pons Rodríguez  Fidel Hernandes Figuera  Maritza Garcia Garcia 《Astronomy Reports》2018,62(6):367-377

The creation of a specialized network of large, wide-angle telescopes for distributed observations of near-Earth space using a Russian–Cuban Observatory is considered. An extremely important goal of routine monitoring of near-Earth and near-Sun space is warding off threats with both natural and technogenic origins. Natural threats are associated with asteroids or comets, and technogenic threats with man-made debris in near-Earth space. A modern network of ground-based optical instruments designed to ward off such threats must: (a) have a global and, if possible, uniform geographic distribution, (b) be suitable for wide-angle, high-accuracy precision survey observations, and (c) be created and operated within a single network-oriented framework. Experience at the Institute of Astronomy on the development of one-meter-class wide-angle telescopes and elements of a super-wide-angle telescope cluster is applied to determine preferences for the composition of each node of such a network. The efficiency of distributed observations in attaining maximally accurate predictions of the motions of potentially dangerous celestial bodies as they approach the Earth and in observations of space debris and man-made satellites is estimated. The first estimates of astroclimatic conditions at the proposed site of the future Russian–Cuban Observatory in the mountains of the Sierra del Rosario Biosphere Reserve are obtained. Special attention is given to the possible use of the network to carry out a wide range of astrophysical studies, including optical support for the localization of gravitational waves and other transient events.  相似文献   

Regional setting and characteristics of the Neoproterozoic Wadi Hamama Zn–Cu–Ag–Au prospect: evidence for an intra-oceanic island arc-hosted volcanogenic hydrothermal system     

Yasser Abd El-Rahman  Adel A. Surour  Abdel Hamid W. El-Manawi  Abdel-Monem A. El-Dougdoug  Sayed Omar 《International Journal of Earth Sciences》2015,104(3):625-644

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Origin of disc lopsidedness in the Eridanus group of galaxies     

R. A. Angiras †  C. J. Jog †  A. Omar †  K. S. Dwarakanath † 《Monthly notices of the Royal Astronomical Society》2006,369(4):1849-1857

The H  i surface density maps for a sample of 18 galaxies in the Eridanus group are Fourier analysed. This analysis gives the radial variation of the lopsidedness in the H  i spatial distribution. The lopsidedness is quantified by the Fourier amplitude A ₁ of the m = 1 component normalized to the average value. It is also shown that in the radial region where the stellar disc and H  i overlap, their A ₁ coefficients are comparable. All the galaxies studied show significant lopsidedness in H  i . The mean value of A ₁ in the inner regions of the galaxies (1.5–2.5 scalelengths) is ≥ 0.2. This value of A ₁ is twice the average value seen in the field galaxies. Also, the lopsidedness is found to be smaller for late-type galaxies; this is opposite to the trend seen in the field galaxies. These two results indicate a different physical origin for disc lopsidedness in galaxies in a group environment compared to the field galaxies. Further, a large fraction (∼30 per cent) shows a higher degree of lopsidedness ( A ₁≥ 0.3). It is also seen that the disc lopsidedness increases with the radius as demonstrated in earlier studies, but over a radial range that is two times larger than done in the previous studies. The average lopsidedness of the halo potential is estimated to be ∼10 per cent, assuming that the lopsidedness in H  i disc is due to its response to the halo asymmetry.  相似文献   

Cenozoic denudation in the Marrakech High Atlas,Morocco: insight from apatite fission‐track thermochronology     

Yves Missenard  Omar Saddiqi  Jocelyn Barbarand  Pascale Leturmy  Geoffrey Ruiz  Fatima‐Zahra El Haimer  Dominique Frizon de Lamotte 《地学学报》2008,20(3):221-228

In North Africa, the High Atlas belt culminates at more than 4000 m. In Morocco, recent work shows that a lithospheric thinning explains about 1000 m of the mean topography, the remaining topography being related to crustal shortening. We combine regional geology with new apatite fission‐track (AFT) ages to constrain the timing of these events in the Marrakech High Atlas (MHA). In the inner belt, 10 AFT ages are comprised between 9 ± 1 and 27 ± 3 Ma. These Neogene ages indicate that the MHA underwent significant denudation during that time. In the southern foreland domain of the belt, three samples give scattered AFT ages between 27 ± 2 and 87 ±5 Ma. Geological evidences allow us to constrain the age of a major denudation event during Middle Miocene age. We propose that it is linked to the thermal doming highlighted in the whole Moroccan Atlas domain.  相似文献   

Assessment of heavy metals contamination in deposited street dusts in different urbanized areas in the city of Ma’an, Jordan   总被引：2，自引：1，他引：1  

Omar Ali Al-Khashman 《Environmental Earth Sciences》2013,70(6):2603-2612

190 Street dust samples were collected from nine different localities including high traffic (desert highway), moderate traffic (city center), light traffic (minor streets), residential streets, school gardens, hospital and health centers, industrial sites, parks and background sites (control) of Ma’an area. The concentrations of Fe, Zn, Ni, Pb, Mn, Cu and Cd were analyzed by flame atomic absorption spectrophotometer to assess and to compare road dust contamination levels of metals among the different types of urban environment. The results showed that dust samples from the urban and industrial site contained significant levels of the metals studied compared to the values obtained from the background site. The variation in concentration of the heavy metals determined from different locations was in the decreasing order as: industrial > high traffic > parks > moderate traffic > hospital and health centers > school gardens > light traffic > background sites. The mean concentrations of the metals were in the order of C _Fe > C _Zn > C _Ni > C _Pb > C _Mn > C _Cu > C _Cd where C is the concentration of these metals in solution. Enrichment factor calculations indicated that Cd, Pb, Zn and Ni were highly enriched. Fossil fuel combustion, wear of brake lining materials, traffic emissions and several industrial processes are considered the main sources of these metals. Assessment of the contamination level in dust sample was estimated based on the geoaccumulation index (I _geo), the pollution index, and integrated pollution index (IPI). The values of IPI are in the following order: Pb > Zn > Cu > Ni > Cd > Mn. All the indices for the metals under consideration were either low or corresponded to middle level of contamination. The use of factor analysis showed that anthropogenic activities seem to be the responsible source of contamination for metals in dust samples.  相似文献   

Landslide susceptibility mapping using certainty factor, index of entropy and logistic regression models in GIS and their comparison at Mugling�CNarayanghat road section in Nepal Himalaya     

Krishna Chandra Devkota  Amar Deep Regmi  Hamid Reza Pourghasemi  Kohki Yoshida  Biswajeet Pradhan  In Chang Ryu  Megh Raj Dhital  Omar F. Althuwaynee 《Natural Hazards》2013,65(1):135-165

Landslide susceptibility maps are vital for disaster management and for planning development activities in the mountainous country like Nepal. In the present study, landslide susceptibility assessment of Mugling?CNarayanghat road and its surrounding area is made using bivariate (certainty factor and index of entropy) and multivariate (logistic regression) models. At first, a landslide inventory map was prepared using earlier reports and aerial photographs as well as by carrying out field survey. As a result, 321 landslides were mapped and out of which 241 (75?%) were randomly selected for building landslide susceptibility models, while the remaining 80 (25?%) were used for validating the models. The effectiveness of landslide susceptibility assessment using GIS and statistics is based on appropriate selection of the factors which play a dominant role in slope stability. In this case study, the following landslide conditioning factors were evaluated: slope gradient; slope aspect; altitude; plan curvature; lithology; land use; distance from faults, rivers and roads; topographic wetness index; stream power index; and sediment transport index. These factors were prepared from topographic map, drainage map, road map, and the geological map. Finally, the validation of landslide susceptibility map was carried out using receiver operating characteristic (ROC) curves. The ROC plot estimation results showed that the susceptibility map using index of entropy model with AUC value of 0.9016 has highest prediction accuracy of 90.16?%. Similarly, the susceptibility maps produced using logistic regression model and certainty factor model showed 86.29 and 83.57?% of prediction accuracy, respectively. Furthermore, the ROC plot showed that the success rate of all the three models performed more than 80?% accuracy (i.e. 89.15?% for IOE model, 89.10?% for LR model and 87.21?% for CF model). Hence, it is concluded that all the models employed in this study showed reasonably good accuracy in predicting the landslide susceptibility of Mugling?CNarayanghat road section. These landslide susceptibility maps can be used for preliminary land use planning and hazard mitigation purpose.  相似文献   

Application of the Linkam TS1400XY heating stage to melt inclusion studies   总被引：1，自引：0，他引：1  

Rosario Esposito  Rita Klebesz  Omar Bartoli  Yury I. Klyukin  Daniel Moncada  Angela L. Doherty  Robert J. Bodnar 《Central European Journal of Geosciences》2012,4(2):208-218

Melt inclusions (MI) trapped in igneous phenocrysts provide one of the best tools available for characterizing magmatic processes. Some MI experience post-entrapment modifications, including crystallization of material on the walls, formation of a vapor bubble containing volatiles originally dissolved in the melt, or partial to complete crystallization of the melt. In these cases, laboratory heating may be necessary to return the MI to its original homogeneous melt state, followed by rapid quenching of the melt to produce a homogeneous glass phase, before microanalyses can be undertaken. Here we describe a series of heating experiments that have been performed on crystallized MI hosted in olivine, clinopyroxene and quartz phenocrysts, using the Linkam TS1400XY microscope heating stage. During the experiments, we have recorded the melting behaviors of the MI up to a maximum temperature of 1360°C. In most of the experiments, the MI were homogenized completely (without crystals or bubbles) and remained homogeneous during quenching to room temperature. The resulting single phase MI contained a homogeneous glass phase. These tests demonstrate the applicability of the Linkam TS1400XY microscope heating stage to homogenize and quench MI to produce homogeneous glasses that can be analyzed with various techniques such as Electron Microprobe (EMP), Secondary Ion Mass Spectrometry (SIMS), Laser ablation Inductively Coupled Plasma Mass Spectrometry (LA ICP-MS), Raman spectroscopy, FTIR spectroscopy, etc. During heating experiments, the optical quality varied greatly between samples and was a function of not only the temperature of observation, but also on the amount of matrix glass attached to the phenocryst, the presence of other MI in the sample which are connected to the outside of the crystal, and the existence of mineral inclusions in the host.  相似文献