http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Salwa K. Hassan,Ahmeh A. El-Abssawy,Mamdouh I. Khoder 한국대기환경학회 2018 Asian Journal of Atmospheric Environment (AJAE) Vol.12 No.4
Formaldehyde (HCHO) is a carcinogenic pollutant, has an active role in tropospheric photochemistry, and can be affected by seasonal variations. To our knowledge, this is the first comprehensive study of the effect of seasonal variation on the levels and behaviours of HCHO in the atmosphere of a suburban area (15 May City) in Cairo. Daytime and nighttime measurements of HCHO were performed from March 2014 to February 2015. The highest average daily concentrations of HCHO were found in summer and the lowest in winter. The difference was statistically significant (p≤0.001). Daily average HCHO concentrations in spring, summer, autumn and winter were higher than the corresponding values in many polluted cities in the world. This was true for both weekdays and weekends. HCHO was higher in daytime than nighttime on weekdays and weekends, and the differences in mean concentrations were statistically significant (p ≤0.001), except during the autumn and winter on weekends. Therefore, the contribution of photochemical reactions in the observed levels of HCHO might be greater than that of traffic emissions. This was further proved by the significant positive correlation found between daytime HCHO concentrations and temperature. HCHO concentrations were higher on weekdays than weekends, the differences in mean concentrations were statistically significant (p≤0.001). This may be attributed to higher emission of HCHO from higher traffic intensity during daytime. Significant positive correlations (p≤0.001) were found between daytime and nighttime HCHO concentrations, both on weekdays and weekends suggesting that HCHO comes from the same sources.
Salwa Mohamed,Amr E. Assie,Nazira Mohamed,Mohamed A Eltaher 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.45 No.3
This article aims to investigate the static deflection and stress analysis of bi-directional functionally graded porous plate (BDFGPP) modeled by unified higher order kinematic theories to include the shear stress effects, which not be considered before. Different shear functions are described according to higher order models that satisfy the zero-shear influence at the top and bottom surfaces, and hence refrain from the need of shear correction factor. The material properties are graded through two spatial directions (i.e., thickness and length directions) according to the power law distribution. The porosities and voids inside the material constituent are described by different cosine functions. Hamilton’s principle is implemented to derive the governing equilibrium equation of bi-directional FG porous plate structures. An efficient numerical differential integral quadrature method (DIQM) is exploited to solve the coupled variable coefficients partial differential equations of equilibrium. Problem validation and verification have been proven with previous prestigious work. Numerical results are illustrated to present the significant impacts of kinematic shear relations, gradation indices through thickness and length, porosity type, and boundary conditions on the static deflection and stress distribution of BDFGP plate. The proposed model is efficient in design and analysis of many applications used in nuclear, mechanical, aerospace, naval, dental, and medical fields.
Unbalanced Magnetic Forces in Rotational Unsymmetrical Transverse Flux Machine
Salwa Baserrah,Keno Rixen,Bernd Orlik 대한전기학회 2012 Journal of Electrical Engineering & Technology Vol.7 No.2
The torque and unbalanced magnetic forces in permanent magnet machines are resultants of the tangential, axial and normal magnetic forces, respectively. Those are in general influenced by pole-teeth-winding configuration. A study of the torque and unbalanced magnetic forces of a small flux concentrating permanent magnet transverse flux machine (FCPM-TFM) in segmented compact structure is presented in this paper. By using FLUX3D software from Cedrat, Maxwell stress tensor has been solved. Finite element (FE-) magneto static study followed by transient analysis has been conducted to investigate the influence of unsymmetrical winding pattern, in respect to the rotor, on the performance of the FCPM-TFM. Calculating the magnetic field components in the air gap has required an introduction of a 2D grid in the middle of the air gap, whereby good estimations of the forces are obtained. In this machine, the axial magnetic forces reveal relatively higher amplitudes compared to the normal forces. Practical results of a prototype motor are demonstrated through the analysis.
PUBLIC EDUCATION SPENDING AND ECONOMIC GROWTH: THE GOVERNANCE THRESHOLD EFFECT
SALWA TRABELSI 중앙대학교 경제연구소 2018 Journal of Economic Development Vol.43 No.1
This paper aims to give reason to the mixed result between the public education spending and growth found largely by the empirical works and to confirm the nonlinear character of this relationship. Using cross countries data averaged during the period 1980-2013, and the structural threshold regression method STR (Kourtellos et al,. 2015) to investigate the heterogeneous effects of the public education spending on growth considering governance indicators as threshold variable, we obtain evidence that this expenditure contributes positively to the economic performance only if the country is above the threshold level and presents good governance otherwise the effect is negative.
Least squares estimator of fractional Ornstein–Uhlenbeck processes with periodic mean
Salwa Bajja,Khalifa Es-Sebaiy,Lauri Viitasaari 한국통계학회 2017 Journal of the Korean Statistical Society Vol.46 No.4
We first study the drift parameter estimation of the fractional Ornstein–Uhlenbeck process (fOU) with periodic mean for every 1/2 < H < 1. More precisely, we extend the consistency proved in Dehling et al. (2016) for 1/2 < H < 3 /4 to the strong consistency for any 1/2 < H < 1 on the one hand, and on the other, we also discuss the asymptotic normality given in Dehling et al. (2016). In the second main part of the paper, we study the strong consistency and the asymptotic normality of the fOU of the second kind with periodic mean for any 1/2 < H < 1.
Salwa Baserrah,Keno Rixen,Bernd Orlik 한국자기학회 2012 Journal of Magnetics Vol.17 No.2
Flux concentrated permanent magnet transverse flux machines, FCPM-TFMs, with segmented stators require multi-turn concentric saddle coils to replace the ring coils, which are normally utilized in conventional layeredphase TFM constructions. In this paper, we investigate the influence of the shape of saddle phase windings and their parameter variations on the output torque productivity. Non-meshed coils evaluated via a finite element method (FEM) to examine the effect of the coil’s location within one phase on machine performance. By using meshed coils, the analysis can be extended to inspect the distributions of magnetic field strength as well as current density in the coils. Throughout the study, the influence of design parameters on the output torque for two stator structures, i.e., a laminated and soft magnetic composite (SMC), are evaluated.
Salwa Khoddam,H. J. Hodges 한국중세근세영문학회 2016 중세르네상스 영문학 Vol.24 No.1
The article investigates the peach as symbol of the forbidden fruit in Milton’s Paradise Lost, Marvell’s “Garden,” and Eliot’s “Prufrock.” Milton focuses on the fruit’s appearance as “downy,” Marvell refers to the peach as “curious,” and Eliot worries that to “dare” to eat a peach could disturb the universe. Milton’s choice of “downy” fits the peach better than what we would now call an apple. Marvell’s choice of “curious” fits the Christian world’s long-held belief that curiosity was the vice that led Eve to try the forbidden fruit. Eliot’s choice of “dare” fits Eve’s having “dar’d” to eat the forbidden fruit in Paradise Lost, for daring to eat the fruit can disturb the universe, as, for example, Eve’s eating did. These three points are supported by context, analysis, explication, connections, etymology, and more. Noted in passing are a few brief references in art and literature to the peach as the forbidden fruit, and these are treated merely to show that such identification is not unheard of. More important are the connections drawn between the fruit in the three poems, for such connections are the focus of this paper.
Salwa Elmeligie,Azza T. Taher,Nadia A. Khalil,Ahmed H. El-said 대한약학회 2017 Archives of Pharmacal Research Vol.40 No.1
Novel series of 1,3,4-trisubstituted azetidin-2-one derivatives 8a–p were synthesized and proposed ascytotoxic agents acting via inhibition of tubulin at thecolchicine binding site. The design of the target compoundswas based upon modification in the structure of the vasculartargeting agent combretastatin A-4 (CA-4). The cisdouble bond linker in CA-4 was replaced with the azetidin-2-one ring aiming to prevent the cis/trans isomerizationthat suppresses the activity of CA-4, thereby enhancing itsantiproliferative activity. All new compounds were investigatedin vitro against MCF-7 and HCT-116 cell lines. Theinhibition of tubulin polymerization by four most potentcompounds 8g, 8j, 8n and 8o was also evaluated. Thesynthesis of the final targets was achieved adopting Staudingerreaction. Molecular modeling studies were performedto rationalize the biological results.