In this paper, an exact analytical propagation formula of Finite Olver-Gaussian Beams (FOGBs) passing through a paraxial ABCD optical system is developed and some numerical examples are performed. The propagation prop...In this paper, an exact analytical propagation formula of Finite Olver-Gaussian Beams (FOGBs) passing through a paraxial ABCD optical system is developed and some numerical examples are performed. The propagation properties of the FOGBs through general optical systems characterized by given ABCD matrix are studied on the basis of the generalized Huygens-Fresnel diffraction integral, which permits to show the behavior of this laser beams family and its properties de-pending of the laser parameters. This research is of interest to prove some investigations done in the past by other researchers.展开更多
In this work, we use the analytical expression of the propagation of Finite Olver-Gaussian beams (FOGBs) through a paraxial ABCD optical system to study the action of radiation forces produced by highly focused FOGBs ...In this work, we use the analytical expression of the propagation of Finite Olver-Gaussian beams (FOGBs) through a paraxial ABCD optical system to study the action of radiation forces produced by highly focused FOGBs on a Rayleigh dielectric sphere. Our numerical results show that the FOGBs can be employed to trap and manipulate particles with the refractive index larger than that of the ambient. The radiation force distribution has been studied under different beam widths. The trapping stability under different conditions is also analyzed.展开更多
In this paper, we introduce a new class of scalar nondiffracting Helmholtz-equation solution. We demonstrate that this novel wave-equation solution has some specific orders;among these ordinary Airy beams which are re...In this paper, we introduce a new class of scalar nondiffracting Helmholtz-equation solution. We demonstrate that this novel wave-equation solution has some specific orders;among these ordinary Airy beams which are regarded as the zeroth order. Moreover, a general expression of these novel beams, which are named Olver Beams and referred to OBs, is developed. The zeroth and the first high orders of the incident OBs are presented theoretically and numerically in this paper. Yet, based on a computer generated holograms method, the generation’s masks of the Finite OBs in first orders are given in this work. Also, the incident transverse intensity distribution in 1-D and 2-D of the first orders of OBs is performed.展开更多
Based on the Collins diffraction formula and by means of the expansion of a hard aperture function into a finite sum of complex Gaussian functions, two analytical approaches of the Finite Olver beams (FOBs) passing th...Based on the Collins diffraction formula and by means of the expansion of a hard aperture function into a finite sum of complex Gaussian functions, two analytical approaches of the Finite Olver beams (FOBs) passing through a paraxial ABCD optical system with a circular annular aperture or a rectangular one are developed in this paper. The propagation properties of the FOBs through an unapertured ABCD optical system or through this last with a circular (or rectangular) aperture or a circular (or rectangular) black screen are deduced, from the main results, as particular cases. Also, the characteristics of Finite ordinary Airy beam passing through the all considered optical systems are derived here that correspond to zeroth-order of the FOBs. According to the predicted formulas, computer simulation examples are given to deepen the understanding of the characteristics of the FOBs passing through some optical systems of annular aperture basis.展开更多
Clogging in the heat exchangers of the phosphoric acid concentration unit is a phenomenon which hinders the proper functioning of the installation. It results in the accumulation of undesirable solid deposits on the p...Clogging in the heat exchangers of the phosphoric acid concentration unit is a phenomenon which hinders the proper functioning of the installation. It results in the accumulation of undesirable solid deposits on the pipes and consequently a decrease of its performance. This deposit is mainly anhydrous or hemihydrate gypsum in addition to Na2SiF6. Phosphoric acid desulphation before its concentration step allows reducing this undesirable effect. Barium carbonate is used for the retention of sulphate ions using a simple experimental protocol which can easily be inserted into the phosphoric acid manufacturing. Four factors: quality of the phosphoric acid to be concentrated, amount of barium carbonate, temperature and time, were studied using design of experiment (DOE) methodology with two-level full factorial design strategy in order to assess their effects on desulphation. Only the first two factors have significant effects. Therefore, for effective sulphate removal, the validated statistical model (R2 = 99.96%) allows to predict the amount of barium carbonate to be used, depending on quality of the phosphoric acid to be concentrated and using the available temperature and time in the industrial process.展开更多
Objective:To study the chemical profile,antimicrobial properties,and synergistic effect with known antibiotics of essential oil extracted from the marine red macroalgae Centroceras clavulatum(C.Agardh)Montagne,collect...Objective:To study the chemical profile,antimicrobial properties,and synergistic effect with known antibiotics of essential oil extracted from the marine red macroalgae Centroceras clavulatum(C.Agardh)Montagne,collected in Morocco.Methods:The chemical composition of the oil was analyzed by gas chromatography-mass spectrometry.The oil was evaluated for antibacterial(Pseudomonas aeruginosa,Escherichia coli,Bacillus subtilis,Micrococcus luteus,Staphylococcus aureus,and Klebsiella pneumoniae),and antifungal activity(Candida albicans,Candida glabrata,Candida krusei,and Candida parapsilosis),by the disc diffusion method.The minimum inhibitory and minimum microbicidal concentrations of the oil were determined,as well as the synergistic effects of its application combined with the antibiotics ciprofloxacin and fluconazole,by the checkerboard method.Results:Thirty molecules were identified in the essential oil,comprising 96.27%of the total oil composition.Monoterpenes such as carvacrol(36.06%)were the most abundant compounds,followed by caryophyllene(14.67%),endo-borneol(9.04%),pyroterebic acid(3.23%)and caryophyllene oxide(3.13%).The oil exhibited a moderate antimicrobial activity with inhibition zone diameters ranging from 9.0 to 15.0 mm.The minimum inhibitory concentration values varied between 0.9 and 14.7 mg/mL,and Bacillus subtilis and Escherichia coli were the more sensitive bacteria with 0.9 and 1.9 mg/mL,respectively.The minimum microbicidal concentration values ranged from 0.4 to 14.7 mg/mL.A significant synergic action was observed when the oil was applied in combination with ciprofloxacin and fluconazole,with fractional inhibitory concentration index values ranging from 0.31 to 0.50.Synergy was found in 80%of the combinations and a 2 to 16-fold reduction of antibiotics MIC was observed.Conclusions:Our findings suggest that the essential oil of Centroceras clavulatum should be further appraised for its potential use in the management of multi-drug resistant microorganisms,with the purpose to restore the activity of standard antimicrobial drugs.展开更多
文摘In this paper, an exact analytical propagation formula of Finite Olver-Gaussian Beams (FOGBs) passing through a paraxial ABCD optical system is developed and some numerical examples are performed. The propagation properties of the FOGBs through general optical systems characterized by given ABCD matrix are studied on the basis of the generalized Huygens-Fresnel diffraction integral, which permits to show the behavior of this laser beams family and its properties de-pending of the laser parameters. This research is of interest to prove some investigations done in the past by other researchers.
文摘In this work, we use the analytical expression of the propagation of Finite Olver-Gaussian beams (FOGBs) through a paraxial ABCD optical system to study the action of radiation forces produced by highly focused FOGBs on a Rayleigh dielectric sphere. Our numerical results show that the FOGBs can be employed to trap and manipulate particles with the refractive index larger than that of the ambient. The radiation force distribution has been studied under different beam widths. The trapping stability under different conditions is also analyzed.
文摘In this paper, we introduce a new class of scalar nondiffracting Helmholtz-equation solution. We demonstrate that this novel wave-equation solution has some specific orders;among these ordinary Airy beams which are regarded as the zeroth order. Moreover, a general expression of these novel beams, which are named Olver Beams and referred to OBs, is developed. The zeroth and the first high orders of the incident OBs are presented theoretically and numerically in this paper. Yet, based on a computer generated holograms method, the generation’s masks of the Finite OBs in first orders are given in this work. Also, the incident transverse intensity distribution in 1-D and 2-D of the first orders of OBs is performed.
文摘Based on the Collins diffraction formula and by means of the expansion of a hard aperture function into a finite sum of complex Gaussian functions, two analytical approaches of the Finite Olver beams (FOBs) passing through a paraxial ABCD optical system with a circular annular aperture or a rectangular one are developed in this paper. The propagation properties of the FOBs through an unapertured ABCD optical system or through this last with a circular (or rectangular) aperture or a circular (or rectangular) black screen are deduced, from the main results, as particular cases. Also, the characteristics of Finite ordinary Airy beam passing through the all considered optical systems are derived here that correspond to zeroth-order of the FOBs. According to the predicted formulas, computer simulation examples are given to deepen the understanding of the characteristics of the FOBs passing through some optical systems of annular aperture basis.
文摘Clogging in the heat exchangers of the phosphoric acid concentration unit is a phenomenon which hinders the proper functioning of the installation. It results in the accumulation of undesirable solid deposits on the pipes and consequently a decrease of its performance. This deposit is mainly anhydrous or hemihydrate gypsum in addition to Na2SiF6. Phosphoric acid desulphation before its concentration step allows reducing this undesirable effect. Barium carbonate is used for the retention of sulphate ions using a simple experimental protocol which can easily be inserted into the phosphoric acid manufacturing. Four factors: quality of the phosphoric acid to be concentrated, amount of barium carbonate, temperature and time, were studied using design of experiment (DOE) methodology with two-level full factorial design strategy in order to assess their effects on desulphation. Only the first two factors have significant effects. Therefore, for effective sulphate removal, the validated statistical model (R2 = 99.96%) allows to predict the amount of barium carbonate to be used, depending on quality of the phosphoric acid to be concentrated and using the available temperature and time in the industrial process.
基金the Researchers Supporting Project number(RSP-2021/56)King Saud University,Riyadh,Saudi Arabia+2 种基金the Foundation for Science and Technology(FCT)the Portuguese National Budget for the UIDB/04326/2019 projectthe FCT Scientific Employment Stimulus(CEECIND/00425/2017).
文摘Objective:To study the chemical profile,antimicrobial properties,and synergistic effect with known antibiotics of essential oil extracted from the marine red macroalgae Centroceras clavulatum(C.Agardh)Montagne,collected in Morocco.Methods:The chemical composition of the oil was analyzed by gas chromatography-mass spectrometry.The oil was evaluated for antibacterial(Pseudomonas aeruginosa,Escherichia coli,Bacillus subtilis,Micrococcus luteus,Staphylococcus aureus,and Klebsiella pneumoniae),and antifungal activity(Candida albicans,Candida glabrata,Candida krusei,and Candida parapsilosis),by the disc diffusion method.The minimum inhibitory and minimum microbicidal concentrations of the oil were determined,as well as the synergistic effects of its application combined with the antibiotics ciprofloxacin and fluconazole,by the checkerboard method.Results:Thirty molecules were identified in the essential oil,comprising 96.27%of the total oil composition.Monoterpenes such as carvacrol(36.06%)were the most abundant compounds,followed by caryophyllene(14.67%),endo-borneol(9.04%),pyroterebic acid(3.23%)and caryophyllene oxide(3.13%).The oil exhibited a moderate antimicrobial activity with inhibition zone diameters ranging from 9.0 to 15.0 mm.The minimum inhibitory concentration values varied between 0.9 and 14.7 mg/mL,and Bacillus subtilis and Escherichia coli were the more sensitive bacteria with 0.9 and 1.9 mg/mL,respectively.The minimum microbicidal concentration values ranged from 0.4 to 14.7 mg/mL.A significant synergic action was observed when the oil was applied in combination with ciprofloxacin and fluconazole,with fractional inhibitory concentration index values ranging from 0.31 to 0.50.Synergy was found in 80%of the combinations and a 2 to 16-fold reduction of antibiotics MIC was observed.Conclusions:Our findings suggest that the essential oil of Centroceras clavulatum should be further appraised for its potential use in the management of multi-drug resistant microorganisms,with the purpose to restore the activity of standard antimicrobial drugs.