A simple formula for shape and depth determination from residual gravity anomalies     

Khalid S. Essa 《Acta Geophysica》2007,55(2):182-190

This paper presents a simple method for shape and depth determination of a buried structure from residual gravity anomalies along profile. The method utilizes the anomaly values of the origin and characteristic points of the profile to construct a relationship between the shape factor and depth of the causative source. For fixed points, the depth is determined for each shape factor. The computed depths are then plotted against the shape factor representing a continuous monotonically increasing curve. The solution for the shape and depth of the buried structure is then read at the common intersection point of the depth curves. This method is applied to synthetic data with and without random errors. Finally, the validity of the method is tested on two field examples from the USA.  相似文献   

基于Photomod 3.11制作数字正射影像     

陈晓玲  江万寿  郝中豫  吴忠宜 《测绘信息与工程》2007,32(5):27-29

介绍了俄罗斯的数字摄影测量系统Photomod 3.11,分析了采用比例尺为1∶20 000的航片制作数字正射影像的流程,试验表明其能满足1∶5 000地形图的精度要求.  相似文献   

An efficient Co-ZSM-5 catalyst for the abatement of volatile organics in air: effect of the synthesis protocol     

A. Aziz  M. Sajjad  M. Kim  K. S. Kim 《International Journal of Environmental Science and Technology》2018,15(4):707-718

Co supported on ZSM-5 (Co-ZSM-5) catalysts was synthesized by wet ion exchange (WIE), impregnation (IM), and in situ hydrothermal (IHT) methods. Their adsorptive catalytic activities for the removal of VOC’s [Benzene, Toluene, Ethylbenzene and Toluene (BTEX)] in air were tested. The physicochemical properties were investigated by XRD, FTIR, SEM, XPS, and low-temperature N₂ adsorption. The results indicate that the catalytic performance of Co-ZSM-5 for VOC’s abatement is effective and the synthesis methods reasonably influence the catalytic activity of Co-ZSM-5. Among three samples prepared by three different methods, the catalyst synthesized by the hydrothermal method possesses the highest adsorptive catalytic activity for BTEX oxidation. The optimized contact time was 60 min. The catalytic activities of the prepared catalysts are varied in the order of IHT > IM > WIE based on the combined removal capacity 59.24 > 34.46 > 23.82 (mg/g). For the Co-ZSM-5 WIE catalysts, the procedure has an evident effect on their catalytic performance. For example, the WIE catalysts prepared with cobalt chloride (II) by ion exchange have a higher acidity and surface area than the catalyst prepared with cobalt chloride (II) by impregnation method but less cobalt content. The excellent performance of IHT catalysts may be endorsed to the better availability of the oxidized form (Co³⁺), due to high content, higher surface area and acidity. Moreover, the Co-ZSM-5 catalyst synthesized by the IHT method shows high stability after being used.  相似文献   

Free vibration of functionally graded beams resting on Winkler-Pasternak foundation     

Mehmet Avcar  Waleed Khalid Mohammed Mohammed 《Arabian Journal of Geosciences》2018,11(10):232

In the present study, the free vibration of functionally graded beams resting on two parameter elastic foundation was examined. The properties of the functionally graded materials were presumed to vary continuously along the thickness direction. The foundation medium was assumed to be linear, homogeneous, and isotropic, and it was modeled by the Winkler-Pasternak model with two parameters for describing the reaction of the elastic foundation on the beam. The functionally graded beam was modeled with classical beam theory. The governing equation including the effects of functionally graded material properties, Winkler-Pasternak elastic foundation was solved using separation of variables. The eigenvalues of yielding fundamental equation versus clamped-clamped, clamped-free, clamped-simply supported, and simply supported-simply supported boundary conditions were found. To corroborate the results, comparisons were carried out with available results for homogeneous and functionally graded beams. The effects of Winkler-Pasternak type elastic foundation and functionally graded material properties on the values of dimensionless frequency parameter of beams were discussed. Briefly, it was found that the dimensionless frequency parameters of beam change according to material properties, presence of elastic foundation, and boundary conditions; moreover, the separate effects of these quantities on each other are interesting.  相似文献   

Cadmium (Cd) concentration in wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis>) grown in Cd-spiked soil varies with the doses and biochar feedstock     

Muhammad Zia ur Rehman  Muhammad Rizwan  Shafaqat Ali  Muhammad Irfan Sohail  Amjad Hussain  Muhammad Farooq Qayyum  Hinnan Khalid  Muhammad Zeeshan  Naveeda Majid 《Arabian Journal of Geosciences》2018,11(21):685

Biochar is considered a promising amendment for the reduction of metal concentration in plants; however, the effects of biochar in terms of dose and feedstock on metal uptake by plants remain widely unclear. In the current study, three individual biochars were prepared at 450 °C from different feedstocks (wheat straw, sukh chain (Pongamia pinnata), and cotton sticks). The main aim was to evaluate their ability to remediate cadmium (Cd)-spiked soil in terms of growth response and Cd uptake by wheat (Triticum aestivum) tissues. Biochars were separately applied at 0, 1, and 2% (w/w) in Cd-spiked soil and wheat was grown until maturity in pots and then morphological and physiological parameters and Cd concentrations in grains, roots, and shoots were determined. The post-harvest soil was analyzed for extractable Cd concentrations. Plants grown in Cd-spiked soil treated with biochars had higher seed germination, lengths of roots, shoots, and spikes, grains per spike and leaf relative water contents, chlorophyll contents, and dry weight of roots, shoots, and grains as compared to the untreated control. Biochar treatments significantly decreased the Cd concentrations in shoots, roots, and grains as well as total Cd uptake by grains. Soil extractable Cd concentrations were significantly decreased with biochar treatments. The application of 2.0% wheat straw biochar was the most efficient treatment in increasing grain yield and decreasing Cd in grains as well as soil extractable Cd than the other two biochars and doses applied.  相似文献   

The Genesis,Classification, Problems and Prospects of Microbial Carbonates:Implications from the Cambrian Carbonate of North China Platform     

Long Wang  Latif Khalid  Riaz Muhammad  Xiaoye Liu 《地球科学进展》2018,33(10):1005-1023

Currently, sedimentologists focus on the challenging issue of microbial carbonates, which are regarded as "one of the sedimentary rocks most difficult to study", having complicated sedimentary fabric. Their characteristic features closely related to microbial activity, distributed over a long period of geological time, and formed in diversified sedimentary environments. The main research concentrations are the calcified microbial mats and biofilms in geological records as the products of lithification and diagenesis. Starting from the origin, this paper systematically reviewed and explained the processes dwelling within two types of microbial communities, the thinner biofilm and the thicker microbial mat, which enabled them to convert into microbial carbonates through biomineralization and lithification. This study proposed that the existence of multiple microbial mats was another important cause for the diversification and complexity of microbial carbonates in addition to its complex depositional process. Moreover, the sedimentary characteristics and classification of different types of microbial carbonates were reviewed, exemplifying the Cambrian microbial carbonates in the North China Platform. These microbial carbonates are suggested to be placed under "bindstone" after Embry and Kloven, which can be further divided into 5 types, stromatolites, thrombolites, oncolites, laminites and leiolites. Dendrolite is not categorized as a separate class, instead attributed to thrombolites. The microbial carbonates may possess good source rock potential because of the enriched organic content, and may also serve as hydrocarbon reservoirs because of certain microbial textures and fabrics leading to significant porosity and permeability. Because of their biomineralization processes related to microbial activity, the microbial carbonates are not only an important window to understand the evolution of the earth's surface environment, but also capable of forming large-scale reservoirs, and their scientific and economic values are self-evident.  相似文献   

Assessment of dune migration hazards against landuse northwest Al-lith City,Saudi Arabia,using multi-temporal satellite imagery     

Khalid Al-Ghamdi  ElSayed Hermas 《Arabian Journal of Geosciences》2015,8(12):11007-11018

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Effects of di-ammonium phosphate on hydraulic,compaction, and shear strength characteristic of sand and clay soils     

Mohamed Galal A. Eltarabily  Abdelazim M. Negm  Oliver C. Saavedra Valeriano  Khalid E. Gafar 《Arabian Journal of Geosciences》2015,8(12):10419-10432

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Determination of possible responses of Radon-222, magnetic effects,and total electron content to earthquakes on the North Anatolian Fault Zone,Turkiye: an ARIMA and Monte Carlo Simulation     

Mohammed  Dawar Hama Khalid  Külahcı  Fatih  Muhammed  Ahmad 《Natural Hazards》2021,108(3):2493-2512

Natural Hazards - Around the world, earthquake forecasting studies have become very important nowadays due to the increase in number of fatal earthquakes annually. This paper proposes to achieve a...  相似文献   

Smooth particle hydrodynamics modelling of liquid-sediment system and coastal wave breaker     

Ng  Fei Chong  Zawawi  Mohd Hafiz  Azman  Aqil  Abas  Aizat  Razak  Norizham Abdul  Aziz  Nurhanani A.  Zahari  Nazirul Mubin 《Ocean Dynamics》2022,72(2):99-114

Ocean Dynamics - In this paper, a two-phase coastal liquid-sediment system and a wave breaker were numerically simulated using a particle-based smooth particle hydrodynamics (SPH). To verify the...  相似文献