82 research outputs found
The electric field strength above atmospheric surface duct
The paper presents a method which allows the calculation of the atmospheric distortion of radar pules, provided that the influence of the atmosphere is to transfer the transmitted signal through a duct. The polarization of the primary sources, whose moment varies arbitrarily in time, is chosen in such a way that it allows the exact determination of the electric field strength at some field point above the duct layer. We can determinate the transient behavior of the electric field strength at any distance above the duct. Keywords: Electromagnetic field; Atmospheric surface duc
The Transient Electromagnetic Field above Atmospheric Surface Duct
The transient electromagnetic field generated by vertical electric dipole in evaluation duct is investigated theoretically. A vertical electric dipole in the surface layer is taken as the source of the electromagnetic field. We determine the electric field strength exactly at some fixed point in the duct layer expansion with time, the image of the primary source permits us to apply the method first for Cagnaird and later extended by De Hoop and Frankena to the cases .Hence, we can give a physically intuitive description of polarization dependence at the time of the electrical field strength. The distinction of different cases where the distances between the receiving and transmitting ends at greater or lesser than the total reflection distance is studied. Keywords: Electromagnetic field, Magnetic dipol
The Transient Electromagnetic Field above Atmospheric Surface Duct
The transient electromagnetic field generated by vertical electric dipole in evaluation duct is investigated theoretically. A vertical electric dipole in the surface layer is taken as the source of the electromagnetic field. We determine the electric field strength exactly at some fixed point in the duct layer expansion with time, the image of the primary source permits us to apply the method first for Cagnaird and later extended by De Hoop and Frankena to the cases .Hence, we can give a physically intuitive description of polarization dependence at the time of the electrical field strength. The distinction of different cases where the distances between the receiving and transmitting ends at greater or lesser than the total reflection distance is studied. Keywords: Electromagnetic field, Magnetic dipol
The response of a vertical dipole above a conducting earth
An exact representation for the electromagnetic field above a conducting earth is investigated theoretically. The time domain response of a vertical magnetic dipole above a conducting half-space is of a crucial importance in the interpretation of air borne electromagnetic data. The classical approach in finding a solution is to apply Fourier inversion to the formal time harmonic solution, leading to a representation in the form of a double infinite integral. Keywords: electromagnetic field, anisotropic and isotropic
The wave functions of conduction electrons in metallic lithium
The aim of this work has been to evaluate fairly reliable wavefunctions for electrons in the conduction band of lithium, mainly with the aim of bringing some light to the question of whether or not there is a marked variation of the wavefunction throughout k-space.An approximately self-consistent potential was constructed, based on the Hartree-Fock-Slater equations and the atomic wavefunctions given by Holoien. The one-electron equation describing the electrons in the conduction band was solved by the method of orthogonalized plane waves, using up to 70-80 waves. The solutions were determined at the four points of highest symmetry in the Brillouin zone and at 14 other points on axes of symmetry. In effect, 126 points throughout the Brillouin zone were thus considered. The eigenvalues are in fair agreement with those obtained by previous calculations, despite the use of a somewhat different potential. It should be stressed that the potential employed was an approximation to the true self-consistent potential in the metal, and not a "pseudopotential". The main conclusions to he derived from the calculated wavefunctions are: 1: Outside the region of the atomic cores the electrons behave essentially as free; near the nuclei the wavefunct-ions behave as a combination of s and p atomic functions. 2: The form of the wavefunctions does not change much throughout the occupied part of the Brillouin zone. This is particularly true for points with the same magnitude of k.The Fermi surface is found to be distorted from a sphere, in the 110 direction. However, it does not touch the zone face, as previously predicted.<p
Removal of Methylene Blue Dyes from Aqueous System Using Composite Polymeric-Apatite Resins
Removal of cationic dyes from industrial effluents is still a big and challenging subject in the field of environmental purification. Millions of tons of cationic dyes are consumed by the textile, rubber, paper, and plastic industries. These dyes have thousands of different chemical structures. Most of them have special properties, such as high hydrophilicity and stability to light or heat. Adsorption is commonly used as a technique for removing dyes. Removal of cationic dyes by adsorption is a promising approach because of its low performance cost and easy technical access. The amount adsorbed of the dye onto the polymeric resin is studied with time for estimating the adsorption mechanism. The adsorption of dye with time shows that mixing period of 10 min is optimum for attaining equilibrium with respect to R1 and R2, while attaining equilibrium with R3 takes 60 min. This findings represent a rapid kinetic for adsorption of MB, particularly R1, on the prepared resins. Different kinetic models were applied on the obtained results and the kinetic parameters were determined. The kinetic models correlate the amount adsorbed of dye with time. The values of calculated adsorption capacity qe and the linear regression coefficient clarify that the studied kinetic model could not fit with the experimental results for adsorption of MB onto R1, R2, and R3. The results of the studied kinetic model clarify that the experimental results for adsorption of MB onto R1, R2, and R3 could be described by kinetic model supporting chemical adsorption. The sorption of MB could be favorably described by the pseudo-second-order kinetic model onto the composite resins. This finding refers to the participation of chemical adsorption within the adsorption mechanism for MB onto R1, R2, and R3
Repair of PCCP By The Gunnite Method
Repair an affected pipes with mortar coating delaminating using the Gunnite method, where the method applied on the affected pipes which the surface area of affected Coating delaminating reach up to entire pipe body, this method applied on more than 480 affected pipes in Man-Made River Project in desert of Libya
Potential antidiabetic effect of ethanolic and aqueous-ethanolic extracts of Ricinus communis leaves on streptozotocin-induced diabetes in rats
Recently, herbal drugs and their bioactive compounds have gained popularity in the management of diabetes mellitus (DM), which has become an epidemic disease all over the world and is especially prevalent in the Kingdom of Saudi Arabia (KSA). This study aimed to investigate the antidiabetic effect of ethanolic and aqueous-ethanolic extracts of wild Ricinus communis (R. communis) leaves in streptozotocin (STZ) induced diabetic rats. Diabetic rats were administered orally with the mentioned extracts at doses of 300 and 600 mg/kg/BW for 14 days, and the obtained results of different biochemical parameters were compared with normal control, diabetic control and standard drug glibenclamide (5 mg/kg/BW). The obtained results revealed a remarkable and significantly (P < 0.05) reverse effect of the body weight loss, observed when diabetic rats were treated with ethanol and aqueous-ethanol extracts at 300 mg/kg/BW. Administration of the ethanol extract at 600 mg/kg/BW significantly (P < 0.05) reduced the blood glucose level. A significant increase in the AST, ALT and ALP levels (P < 0.05) was observed in the diabetic control and in the experimental groups with glibenclamide which was also significantly (P < 0.05) lowered after treatment with extracts at special doses. Total proteins, albumin, total bilirubin, direct bilirubin, creatinine and urea were also investigated and compared to the corresponding controls. We showed that administration of R. communis extract generally significantly (P < 0.05) ameliorated the biochemical parameters of diabetic rats. Also, the changes in serum electrolyte profile were assessed and the results demonstrate that administration of extracts at concentration of 600 mg/kg/BW generally inhibits the alteration maintain their levels. The obtained data imply the hypoglycemic effects of this plant, which may be used as a good alternative for managing DM and therefore validating its traditional usage in KSA
Pathogenicity of three genetically distinct and highly pathogenic Egyptian H5N8 avian influenza viruses in chickens
In late 2016, Egypt encountered multiple cases of the highly pathogenic avian influenza (HPAI) virus of the H5N8 subtype. In a previous study, three distinct genotypes, including A/common-coot/Egypt/CA285/2016 (H5N8) (CA285), A/duck/Egypt/SS19/2017 (H5N8) (SS19), and A/duck/Egypt/F446/2017 (H5N8) (F446), were isolated from wild birds, a backyard, and a commercial farm, respectively, during the first wave of infection. In this current study, we investigated the differences in the pathogenicity, replication and transmissibility of the three genotypes and A/chicken/Egypt/15S75/2015 (H5N1) (S75) was used as the control. The intravenous pathogenicity index was between 2.68 and 2.9. The chicken lethal dose 50 values of F446, SS19 and CA285 were 103.7, 103.7, an 104 with a natural route of infection, respectively. These strains took longer than S75 to cause death when infection was carried out through the natural route (HPAI H5N1). After inoculation with the original concentration of 105 and 106 egg infective dose 50 (EID50), F446 had a higher mortality rate with short mean death times of 4, and 7 days, respectively compared with the other H5N8 viruses. Chickens inoculated with F446 and contacted exposed chickens infected with F446 showed the highest viral titer with remarkable differences in all H5N8 tested swabs at 2-4 days postinfection (dpi) compared to S75 at 2 dpi. This indicates that F446 had a more efficient transmission and spread from contact exposed birds to other birds. All H5N8 viruses were able to replicate systematically in all organs (trachea, brain, lung, and spleen) of the chicken with high viral titer with significantly different and more pathological changes observed in F446 than in other H5N8 viruses at 2 and 4 dpi. Compared with H5N1, we recorded a significantly high viral titer in the samples obtained from the lung, brain and both cloacal and tracheal swabs at 2 and 4 dpi, respectively and in the samples obtained from the spleen at 2 and 4 dpi among the experimental chicken. The comparative pathogenesis study revealed that in comparison with the other HPAI H5N8 viruses, the genotype F446 was more pathogenic, and showed more efficient viral replication and transmissibility in chickens in Egypt. The genotype F446 also showed a high viral titer than HPAI H5N1 and short mean death time at the third day after inoculation with 106 and 105 EID50, which revealed a conservation of certain H5N8 genotypes and a decrease in the incidence of H5N1
Total photoproduction cross-section at very high energy
In this paper we apply to photoproduction total cross-section a model we have
proposed for purely hadronic processes and which is based on QCD mini-jets and
soft gluon re-summation. We compare the predictions of our model with the HERA
data as well as with other models. For cosmic rays, our model predicts
substantially higher cross-sections at TeV energies than models based on
factorization but lower than models based on mini-jets alone, without soft
gluons. We discuss the origin of this difference.Comment: 13 pages, 9 figures. Accepted for publication in EPJC. Changes
concern added references, clarifications of the Soft Gluon Resummation method
used in the paper, and other changes requested by the Journal referee which
do not change the results of the original versio
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