Application of piezoelectric transducers in simulated rainfall erosivity assessment     

Mohamed A. M. Abd Elbasit  Hiroshi Yasuda  Atte Salmi 《水文科学杂志》2013,58(1):187-194

Abstract

Rainfall simulators have often been used to mimic natural rainfall for studies of various land-surface and water interaction processes. The characteristics of the simulated rainfall are the main indicators used to judge the performance of the rainfall simulators. The aim of this study is to investigate the potential of piezoelectric transducers for measuring and evaluating a dripper-type simulated rainfall drop-size distribution (DSD) and kinetic energy (KE). The directly measured KE was significantly correlated with the estimated KE using the drop-size distribution and empirical rain drop fall velocity relationships. This result emphasizes the potential use of the piezoelectric sensor to directly measure and evaluate rainfall kinetic energy. Also, the relationship between rainfall intensity and KE showed good patterns of agreement between simulated rainfall and natural rainfall.

Citation Abd Elbasit, M. A. M., Yasuda, H. & Salmi, A. (2011) Application of piezoelectric transducers in simulated rainfall erosivity assessment. Hydrol. Sci. J. 56(1), 187–194.  相似文献   

Rogue wave in Titan’s atmosphere     

S. K. El-Labany  W. M. Moslem  N. A. El-Bedwehy  R. Sabry  H. N. Abd?El-Razek 《Astrophysics and Space Science》2012,338(1):3-8

Rogue wave in a collisionless, unmagnetized electronegative plasma is investigated. For this purpose, the basic set of fluid equations is reduced to the Korteweg-de Vries (KdV) equation. However, when the frequency of the carrier wave is much smaller than the ion plasma frequency then the KdV equation is also used to study the nonlinear evolution of modulationally unstable modified ion-acoustic wavepackets through the derivation of the nonlinear Schr?dinger (NLS) equation. In order to show that the characteristics of the rogue wave is influenced by the plasma parameters, the relevant numerical analysis of the NLS equation is presented. The relevance of our investigation to the Titan’s atmosphere is discussed.  相似文献   

Degradation and Leaching of Napropamide in BRIS Soil Amended with Chicken Dung and Palm Oil Mill Effluent     

Fardin Sadegh‐Zadeh  Abd Wahid Samsuri  Othman Radziah  Omar Dzolkhifli  Bahi Jalili Seh‐Bardan 《洁净——土壤、空气、水》2012,40(6):599-606

The degradation and leaching of napropamide were compared between Beach Ridges Interspersed with Swales (BRIS) soil samples, and the same soil samples amended with 20 mg ha^?1 of either chicken dung (CD) or palm oil mill effluent (POME). The effects of removing dissolved organic carbon (DOC) from the soil samples on napropamide degradation and leaching were also studied. The addition of CD and POME to BRIS soil increased the napropamide half‐life values to 69 and 49.5 days, respectively. Sterilization of the soil samples resulted in partial inhibition of napropamide degradation in all soil samples. The half‐lives of napropamide in BRIS soils receiving 0, 20, 100, and 200 mg kg^?1 of DOC derived from CD were 43, 46.2, 53.4, and 63 days, respectively. The napropamide half‐lives in soil samples treated with 0, 20, 100, and 200 mg kg^?1 of DOC derived from POME were 43, 49.2, 57.7, and 69 days, respectively. However, in the sterilized soil samples, there were no significant effects of adding DOC derived from either CD or POME on napropamide half‐lives. Incorporating either CD or POME decreased napropamide leaching and total amounts of napropamide remained in the soil columns after two pore volumes of water has been leached were higher in the amended than the non‐amended soil. The CD was more effective in decreasing napropamide leaching than the POME. There were no effects of DOC on napropamide leaching in all soil treatments.  相似文献   

Environmental and Health Impacts of Successive Mineral Fertilization in Egypt     

Ahmed A. Abdelhafez  Hassan H. Abbas  Rafat S. Abd‐El‐Aal  Nabil F. Kandil  Jianhua Li  Wahballah Mahmoud 《洁净——土壤、空气、水》2012,40(4):356-363

Excessive amounts of mineral fertilizers are unnecessarily applied to agricultural soils in Egypt to increase crop yield. The current study aims at assessing the impacts of fertilization with different mineral fertilizers for different cultivation periods on the accumulation of heavy metals in soils and plants grown thereon. In addition, human risks resulted due to the exposure to these metal ions through ingestion, and dermal routes were evaluated. Soil and plant samples were collected from several locations in El‐Behira Governorate, Egypt and their heavy metal contents were measured. The result indicated that there is a continuous accumulation of heavy metals in the soils and the plants grown thereon. Calculation of the hazard index (HI) revealed that humans, especially children, have a potential health risk for both Pb and Cd, which have levels greater than the safe level (1). Finally, the obtained results showed that the continuous application of mineral fertilizers containing high levels of heavy metals pose a potential health threat.  相似文献   

Aeromagnetic signature analysis of Gasus area and its surrounding,central eastern desert,Egypt     

O. A. Zaki  S. H. AbdAlnabi  S E. Abd El Wahab  A. A. Ismail  N. M. Soliman 《Arabian Journal of Geosciences》2017,10(14):310

This study presents analysis and interpretation of aeromagnetic data to construct subsurface structure maps and determine the depths to magnetic basement. Subsequent analysis steps are applied to the total magnetic intensity (TMI) data. These steps include Reduction to the Pole (RTP) map that was derived from the TMI map then subjected to spectral frequency analysis to isolate RTP map into high and low frequencies and determine pseudo-depth for each map from power spectrum in which there were two main average levels (interfaces) at depth 1.3 and 0.7 km for the deep-seated and near-surface magnetic structures, respectively. 3D Euler deconvolution technique is applied to calculate the depth to the magnetic contacts; the results show clustering of solutions, the shallow solutions are related to the outcrops less than 80 m from flight level, and the solutions which are related to sedimentary cover locations (Um al-Huweitat, Wasif, and Mohamed Rabah basins) are ranged between 200 and to more than 1100 m. Moreover, anomaly enhancement techniques such as tilt derivative (TD), horizontal tilt derivative (TDX), and source edge detect (SED) are applied to enhance shallow features, and determining structure element boundary for both shallow- and deep-seated anomalies and revealing possible faults such as 2D forward modeling are applied to selected profiles to adjust the interpreted structures and map the boundaries and basement relief of the three basins (Mohammed Rabah, Wasif, and Um al-Huweitat). The analysis shows that the study area is affected with network of dip–slip faults due to high shearing and compression stress which formed grabens and horsts at different depth levels in the study area. The trends of predominant faults related to deep-seated structures are NW–SE with depths ranged between 1 and 1.4 km and in regard to the shallow-seated structure, the predominant fault trends are NW–SE, NNW–SSE, and NNE–SSW with depths ranged between 0.3 and 0.8 km.  相似文献   

Impacts of karst phenomena on engineering properties of limestone foundation bed,Ar Riyadh,Saudi Arabia     

Ahmed K. Abd El-Aal  Alaa A. Masoud 《Arabian Journal of Geosciences》2017,10(15):347

Evaluation of mechanical and petrophysical properties of the karst limestone became essential to avoid future risks in the construction of new urban cities built on limestones. Therefore, this study aims to evaluate the impact of karsts phenomena on engineering properties of limestone foundation bed at Ar Riyadh in Saudi Arabia. Three hundred core plugs were obtained by rotary drilling at depths ranging from the ground surface to 20 m collected from 24 boreholes in two sites: (1) karst limestone (KL) at Al Aziziyah district and (2) massive hard limestone (HL) at Hittin district in Ar Riyadh city, Saudi Arabia. Petrographic, SEM, EDX, and XRD analyses are used to identify the mineralogical composition and microstructures of limestone samples. The petrophysical properties included the ovendry density, P-wave, and porosity where the mechanical properties covered the uniaxial compressive strength (UCS), point load strength index (PLI), and rock quality designation (RQD) for the karst and hard limestone samples. KL is characterized by 17.11% total porosity, 14.71% water absorption, 32.1 MPa UCS, 1.70 g/cm³ ovendry density (γ dry), 51% weathered RQD, 5.49 MPa medium shear strength, and low modulus of deformation of the plate loading test. HL showed 11.63% total porosity, 9.45% water absorption 43.1 MPa UCS, 2.50 g/cm³ ovendry density (γ dry), 78% hard to fresh rock affinity RQD, and 9.93 MPa high strength and high modulus of deformation of the plate loading test. For the water absorption (%), KL at Al Aziziyah district showed a range of 12.85–17.80% averaged 14.71%. HL at Hittin district varied between 7.04 and 11.29% with an average of 9.45%. KL proved to be dense with ovendry density (γ dry) averaged at 1.70 g/cm³ while HL showed very dense affinity of 2.50 g/cm³. KL clarified a UCS range from 22.5 to 40.1 MPa and an average of 32.1 MPa while HL showed a range from 35.4 t o 48.1 MPa with an average of 43.1 MPa. KL is moderately weathered with RQD average of 51% while HL showed a hard to fresh rock affinity of 78%. Point load test clarified a medium shear strength with 5.49 MPa for KL and high strength of 9.93 MPa for HL. Plate loading tests indicated low and high modulus of deformation for KL and HL, respectively. Results of petrographical analyses and XED of limestone samples showed that the strength parameters of samples mostly composed of micrite (mudstone/wackestone) and dolomite in hard limestone of Hittin district. In Al Aziziyah district (KL), the samples mostly consist of foraminifera and high amount of calcite as in karst limestone (wackestone/packstone). Rock mechanical tests with combination of fabric analyses have shown that strength parameters depend not only on the amount of karst but also on the amount of allochem. Major geomechanical differences between the two types of limestone provide the proper base for prioritizing areas to alleviate future risks and sustainable urban planning for decision makers. The karstic limestone, therefore, is considered as an acceptable foundation bed for light engineering structures. However, for heavy structures and buildings, improving the foundation bed strength by grouting, cement injection, and mat foundations is necessary to avoid future failure risks.  相似文献   

Ontogenetic changes in feeding and food preferences of the dog conch Laevistrombus canarium Linnaeus 1758 (Mollusca: Gastropoda) from Merambong shoal,Malaysia     

Husna  Wan Nurul Wan Hassan  Mazlan  Abd Ghaffar  Cob  Zaidi Che 《中国海洋湖沼学报》2017,35(5):1230-1238

Laevistrombus canarium is one of the marine gastropod mollusks that have high commercial value,particularly in the aquaculture sector in Malaysia.This study was conducted to determine the feeding and food items of L.canarium at dif ferent ontogenetic stages(juveniles,sub-adults and adults)from Merambong shoals,Malaysia.Field observations on feeding activity were conducted,followed by detailed laboratory analysis on the stomach content.Five-minutes observations on randomly selected individuals were conducted at the fi eld sampling site and their feeding activities were recorded with reference to age stage.Various shell sizes from each ontogenetic stage were randomly collected and quickly anaesthetized with ice and preserved in 10%formalin before being transported to the laboratory for stomach content analyses.Field observations showed that L.canarium mainly grazed on epiphytes occurring on seagrass(46.67%),followed by sediment surface(40%)and epiphytes occurring on macroalgae(13.33%).Stomach content analyses showed a signifi cant dif ference(P0.05)in gastro-somatic index(Gasi)between the juveniles(0.39±0.05),sub-adults(0.68±0.09)and adults(0.70±0.05)(P0.05).Food items found in the conch stomach include diatoms,detritus,foraminifera,seagrass and macroalgae fragments,sand particles and shell fragments.The Index of Relative Importance(%IRI)indicates three main types of food dominated the three ontogenetic stages namely diatoms,sand particles and detritus.However,no signifi cant diff erence(P0.05)was detected between the three main food items(diatoms,sand particles and detritus)among the ontogenetic stages.Therefore,feeding activity revealed the role of the dog conch in the marine food network.While,classifi cation of the types of food consumed by L.canarium through stomach content analysis determines the particular position of the gastropod in the food chain.Further studies are needed to provide a better insight between trophic relationships of L.canarium with marine ecosystem.  相似文献   

A Neural-Network Approach to the Determination of Aquifer Parameters   总被引：8，自引：0，他引：8  

Abd. Rashid Abd. Aziz  Kau-Fui Vincent Wong 《Ground water》1992,30(2):164-166

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Influence of the alteration processes on the origin of uranium and europium anomalies in trachyte, central Eastern Desert, Egypt     

Y. H. Dawood  H. H. Abd El-Naby  A. A. Sharafeldin 《Journal of Geochemical Exploration》2004,81(1-3):15-27

El Atshan mining area, central Eastern Desert, represents one of the uranium occurrences related to alkaline volcanic rocks in Egypt. Based on the plot of total alkali elements versus silica, these rocks are classified as trachytes. The U and Eu anomalies appear to be derived from trachyte exposed to a long period of alteration and rock–fluid interaction. The trachyte has been subjected to two phases of alteration. The pronounced chemical changes include the mobility of Si, Na, Fe, U, Zn and REE and the immobility of Mg, Th, Hf, Ta and Sc. The late stage hydrothermal solutions caused the breakdown of the feldspars by losing sodium, potassium and partially silica and eventually formation of argillic alteration products, dissolution of iron-bearing sulphides, formation of iron-oxy hydroxides and corrosion of primary uranium minerals forming uranyl oxide hydrates. The acidic water percolating through the fractured trachyte rock leached not only available major or trace elements, but also REE. Eu originally incorporated in feldspars as Eu⁺² has been oxidized to Eu⁺³ and subsequently leached away leaving a negative anomaly in the host rock. The leached U and Eu were then transported most probably as carbonate complexes. The second phase of alteration occurred at the near surface profile when the late stage hydrothermal fluids cool to the temperature of meteoric water and may have mixed with it, the pH of the fluids would shift to more alkaline values and at these conditions U and Eu were precipitated into the fracture system mainly by being adsorbed on the clay minerals and probably coprecipitated with iron oxy-hydroxides.  相似文献   

Sustainable development and international cooperation in the Eastern Nile Basin     

Salah El-Din Amer  Yacob Arsano  Atta El-Battahani  Osman El-Tom Hamad  Magdy Abd El-Moenim Hefny  Imeru Tamrat  Simon A. Mason 《Aquatic Sciences - Research Across Boundaries》2005,67(1):3-14

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