Collision induced rotational excitation of AlF (X 1Σ+) by para-H2 (j=0)     

Nadjinangar Gotoum  Kamel Hammami  L. C. Owono?Owono  Nejm-Eddine Jaidane 《Astrophysics and Space Science》2012,337(2):553-561

Rotational excitation cross sections and rate coefficients of AlF collisions with para-H₂ are computed at low temperature, i.e., for T≤70 K. Prior to collisional calculations, a four-dimensional (4D) potential energy surface (PES) for the AlF-H₂ system is calculated at the ab initio Coupled-Cluster level of the theory with an aug-cc-pVQZ Gaussian basis set. This 4D-PES is further reduced to a two-dimensional (2D) PES based on the considerations related to collisional studies with para-H₂. The [Al-F] and [H-H] bond lengths are frozen at their experimental equilibrium value r _e =1.654369 bohr and r _e =1.4011 bohr respectively. The interaction energy presents a global minimum located ∼63 cm⁻¹ below the AlF-H₂ dissociation limit. With this PES, cross sections are determined in the Close-Coupling (CC) approach and rate coefficients are inferred by averaging the cross sections over a Maxwell-Boltzman distribution of kinetic energies. These quantities are significantly magnified in comparison with their AlF-He counterparts. The already observed propensity towards ΔJ=1 transitions for AlF-He remains.  相似文献   

A fast topographic characterization of seismic station locations in Iran through integrated use of digital elevation models and GIS     

Sadra Karimzadeh  Masakatsu Miyajima  Batoul Kamel  Vera Pessina 《Journal of Seismology》2015,19(4):949-967

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Effect of Stress-Strain Conditions on Physical Precursors and Failure Stages Development in Rock Samples     

Kamel Baddari  Anatoly D. Frolov  Victor Tourtchine  Fayçal Rahmoune  Said Makdeche 《Acta Geophysica》2015,63(1):62-102

Precursory stages of failure development in large rock samples were studied and simultaneous observations of the space-time variation of several physical fields were carried out under different stress-strain states. The failure process was studied in detail. A hierarchical structure of discreet rock medium was obtained after loading. It was found that the moisture reduced the rock strength, increased the microcrack distribution and influenced the shape of the failure physical precursors. The rise in temperature up to 400 °C affected the physical precursors at the intermediate and final stages of the failure. Significant variations were detected in the acoustic and electromagnetic emissions. The coalescence criterion was slightly depending on the rock moisture and temperature effect. The possibility of identifying the precursory stage of failure at different strain conditions by means of a complex parameter derived from the convolution of physical recorded data is shown. The obtained results point out the efficiency of the laboratory modelling of seismic processes.  相似文献   

Geochemical assessment,mixing behavior and environmental impact of thermal waters in the Guelma geothermal system,Algeria     

Bouaicha  Foued  Dib  Hénia  Bouteraa  Oualid  Manchar  Nabil  Boufaa  Kamel  Chabour  Nabil  Demdoum  Abdeslam 《中国地球化学学报》2019,38(5):683-702

A study of thirteen geothermal springs located in the geothermal field of Guelma, northeastern Algeria, was conducted. Samples were collected during the period between January 2014 and February 2016. Geochemical processes responsible for the chemical composition of thermal and mineralized water were evaluated. The hydrochemical analysis shows that the thermal waters are characterized by the presence of two different chemical facies, the first type SO₄–Ca in the east, west and south of Guelma, the second type HCO₃–Ca in the south. This analysis also attributed to sodium, chlorides, and sulfates to an evaporitic terrigenous origin by the molar ratio Sr²⁺/Ca²⁺. The thermal spring waters from Guelma geothermal system have a meteoric origin, and all samples are immature with strong mixing between hot and shallow waters with 19–38.5% rate of mixing. The silica geothermometer shows that these thermal waters have a temperature varying from 84 to 122 °C and that the water came from a depth of 2100–3000 m through a fault system that limits the pull-apart basin of Guelma. Potential environmental effluent from thermal spas could pollute in both the irrigation and drinking waters, and which imposes danger on the health of the inhabitants of the region.

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Third-order Uranus-Neptune theory by Hori's method     

Osman M. Kamel 《Earth, Moon, and Planets》1989,45(2):127-137

We construct a U-N secular canonical planetary theory of the third order with respect to planetary masses. The Hori-Lie procedure is adopted to solve the problem. Expansions have been carried out by hand, neglecting powers higher than the second with respect to the eccentricity-inclination. We take into account the principal as well as the indirect part of the planetary disturbing function. The theory is expressed in terms of the Poincaré canonical variables, referring to the Jacobi-Radau set of origins. We assume that the 1:2 U-N critical terms and its multiples are the only periodic terms.  相似文献   

Second order secular planetary theory for the four major planets     

Osman M. Kamel  Abdel Aziz Bakry 《Earth, Moon, and Planets》1984,31(2):123-134

We generalize our results of a second order Jupiter-Saturn planetary theory to be applicable for the case of the four major planets.We use the Von Zeipel method and we neglect powers higher than the third with respect to the eccentricities and sines of the inclinations in our expansions. We consider the critical terms as the only periodic terms.  相似文献   

The establishment of the national gravity standard base net of Egypt (N.G.S.B.N.-77)     

H. Kamel  A. Nakhla 《Journal of Geodynamics》1987,7(3-4)

The earliest gravity measurements in Egypt were carried out by the Anglo-Egyptian Oil Company using Holweck-Lejay pendulum in the period 1937–1940.The measurement comprised few stations (about 41) in restricted areas along both the Western and Eastern coasts of the Gulf of Suez.During the period 1950–1951 Prof. G. Woolard made 21 gravimetric measurements in Egypt as a part of the world-wide gravity base net. Thi was refeered to Potsdam absolute value which was considered as the World Gravity Datum.In 1974, a new world-wide gravity net was published (I.G.S.N.71) which introduced a new concept for the world gravity reference datum, and consequently has replaced the Potsdam System. Since then, it was recommended that a national gravimetric network of base stations in Egypt on the basis of the I.G.S.N.-71 be established within the frame of establishing a gravity map of Egypt.In the period from January 1975, The General Petroleum Company carried out 624 gravity observations throughout the country. These measurements have been combined with the I.G.S.N.-71 values to form 65 gravity base points which in turn from the N.G.S.B.N. (Fig. 1).  相似文献   

Assessing seasonal variations and aquifer vulnerability in coastal aquifers of semi-arid regions using a multi-tracer isotopic approach: the case of Grombalia (Tunisia)     

Siwar Kammoun  Viviana Re  Rim Trabelsi  Kamel Zouari  Salvatore Daniele 《Hydrogeology Journal》2018,26(8):2575-2594

The Grombalia aquifer (NE Tunisia) is an example of an important source of water supply for regional and national development, where the weak controls over abstraction, fertilizer application and waste disposal, coupled with limited knowledge of aquifer dynamics, is causing aquifer over-exploitation and water quality degradation. Assessing the key role of groundwater in water-resources security is therefore of paramount importance to support new actions to preserve water quality and quantity in the long-run. This study presents one of the first investigations targeted at a complete assessment of aquifer dynamics in the Grombalia aquifer. A multi-tracer hydrogeochemical and isotopic (δ²H, δ¹⁸O and ³H) approach was used to study the influence of seasonal variation on piezometric levels, chemical and isotopic compositions, and groundwater recharge. A total of 116 samples were collected from private wells and boreholes during three periods in a 1 year monitoring campaign (February–March 2014, September 2014 and February 2015). Results revealed the overall unsuitability of groundwater for drinking and irrigation purposes (NO₃?>?50 mg/L in 51% of the wells; EC >1,000 μS/cm in 99% of the wells). Isotopic balance coupled to piezometric investigation indicated the contribution of the shallow aquifer to deep groundwater recharge. The study also revealed the weakness of ‘business as usual’ management practices, highlighting possible solutions to tackle water-related challenges in the Grombalia region, where climate change, population growth and intensive agricultural activities have generated a large gap between demand and available water reserves, hence becoming a possible driver for social insecurity.  相似文献   

The elimination of the critical terms of a first order Uranus-Neptune theory through Hori's method     

Osman M. Kamel 《Earth, Moon, and Planets》1982,27(4):407-415

An outline for the elimination of the critical terms of a first order Uranus-Neptune theory is presented with a stress on the application of Hori's procedure to the problem.  相似文献