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排序方式: 共有161条查询结果,搜索用时 31 毫秒
91.
Magar Hend Samy Abbas Mohammed Nooredeen Ali Mounir Ben Ahmed Mona A. 《Journal of Solid State Electrochemistry》2020,24(3):723-737
Journal of Solid State Electrochemistry - Analysis of saliva is a potential diagnostic tool in the management of human diseases. Analysis of saliva in healthy individuals is vital to comparison in... 相似文献
92.
Khalid Sbiaai Adil Eddiai Yahia Boughaleb M’hammed Mazroui Jean-Yves Raty Mounir Meddad Abdelkader Kara 《Optical and Quantum Electronics》2014,46(1):15-22
A semi-empirical potential according to the embedded atom, has been applied to investigate the diffusion of trimers by computing the energy barriers for different mechanisms. Our attention was more focused on the leapfrog process which is likely to occur on missing row surfaces. The activation barriers of this mechanism are calculated using drag method at 0K. These barriers are found to be 0.64 and 0.68 eV for hopping out the channel for $\mathrm{Cu }_{3}/\mathrm{Ag }(110) \mathrm{and Ag }_{3}/\mathrm{Cu }$ (110) respectively. While for hopping down at the other side they are about 0.42 and 0.32 eV. Moreover, a deep metastable position is observed during leapfrog diffusion leading to some spectacular trimer motion. At high temperature and essentially for $\mathrm{Cu }_{3}/\mathrm{Ag }$ (110), we also observed a competition between leapfrog process and concerted jump mechanism with a deformation of trimer geometry. Implications of these findings are briefly discussed. 相似文献
93.
We introduce an axiomatic formalism for the concept of the center of a set in a Euclidean space. Then we explain how to exploit possible symmetries and possible cyclicities in the set in order to localize its center. Special attention is paid to the determination of centers in cones of matrices. Despite its highly abstract flavor, our work has a strong connection with convex optimization theory. In fact, computing the so-called “incenter” of a solid closed convex cone is a matter of solving a nonsmooth convex optimization program. On the other hand, the concept of the incenter of a solid closed convex cone has a bearing on the complexity analysis and design of algorithms for convex optimization programs under conic constraints. 相似文献
94.
95.
Mounir Hajli 《Mathematische Nachrichten》2015,288(14-15):1622-1633
Motivated by the work of Abreu and Freitas 1 , we study the invariant spectrum of the Laplace operator associated to hermitian line bundles endowed with invariant metrics over . 相似文献
96.
Mounir B. Ibrahim 《Applied Scientific Research》1987,44(3):287-302
A one-equation low-Reynolds number turbulence model has been applied successfully to the flow and heat transfer over a circular cylinder in turbulent cross flow. The turbulence length-scale was found to be equal 3.7y up to a distance 0.05 and then constant equal to 0.185 up to the edge of the boundary layer (wherey is the distance from the surface and is the boundary layer thickness).The model predictions for heat transfer coefficient, skin friction factor, velocity and kinetic energy profiles were in good agreement with the data. The model was applied for Re 250,000 and Tu0.07.Nomenclature
µ,C
D
Constants in the turbulence kinetic energy equation
-
C
1,C
2
Constants in the turbulence length-scale equation
-
Skin friction coefficient
atx
-
D
Cylinder diameter
-
F
Dimensionless flow streamwise velocityu/u
e
-
k
Turbulence kinetic energy =1/2 the sum of the squared three fluctuating velocities
-
K
Dimensionless turbulence kinetic energyk/u
e
/2
-
I
Dimensionless temperature (T–T
w
)/(T
–T
w
)
-
l
Turbulence length-scale
-
l
e
Turbulence length-scale at outer region
- Nu
D
Nusselt number
-
p
Pressure
- Pr
Prandtl number
- Pr
t
Turbulent Prandtl number
- Pr
k
Constant in the turbulence kinetic energy equation
-
R
Cylinder radius
- Re
D
Reynolds number
u
D/µ
- Re
x
Reynolds number
u
x/µ
- R
K
Reynolds number of turbulence
-
T
Mean temperature
-
T
Mean temperature at ambient
-
T
s
Mean temperature at surface
- Tu
Cross flow turbulence intensity,
-
u
Mean flow streamwise velocity
-
u
Fluctuating streamwise velocity
-
u
e
Mean flow velocity at far field distance
-
u
Mean flow velocity at ambient
-
u*
Friction velocity
-
v
Mean velocity normal to surface
-
V
Dimensionless mean velocity normal to surface
-
x,x
1
Distance along the surface
-
y
Distance normal to surface
-
Dimensionless pressure gradient parameter
-
Boundary layer thickness atu=0.9995u
e
-
Transformed coordinate iny direction
-
Fluid molecular viscosity
-
t
Turbulent viscosity
-
eff
+
t
- µ
Fluid molecular viscosity at ambient
-
Kinematic viscosity/
-
Density
-
Density at ambient
-
w
Wall shear stress
-
w,0
Wall shear stress at zero free stream turbulence 相似文献
97.
MANSOURI Said MAJDOUBI Hicham HADDAJI Younesse TAMRAOUI Youssef EL ACHABY Mounir MANOUN Bouchaib ABOURRICHE Abdelkrim HANNACHE Hassan OUMAM Mina 《高等学校化学研究》2020,36(6):1339-1347
This paper discusses the elaboration of adsorbents from oil shale. The experimental designs a response surface methodology(RSM), which has been applied to optimize the significant preparation factors, such as temperature, time, and the activating agent percentage. The results obtained from central composite design(CCD) revealed that the interaction between the factors was significant for the maximum quantity of adsorption(response). Planned results have shown that a maximum quantity of adsorption for methylene blue is 65 mg/g, which could be achieved with a temperature of 275℃ over 2 h and a percentage of the activating agent of 45%. The predicted values agreed with the experimental finding, with a determination coefficient(R2) of 0.96. The model has been validated by experiments after conditions optimization. The new material(RHO) was characterized by cation exchange capacity, zero charge pH, surface functions, X-ray fluorescence, specific surface area, and electron microscopy analysis. Phenol adsorption was determined using Langmuir, Freundlich and Temkin, which were used to describe the adsorption isotherms. The adsorption capacity of the material was about 263 mg/g, and the kinetic studies showed rapid adsorption. 相似文献
98.
This work proposes a new numerical method for determining the shear stress, which does not need any preassumption about the
exact behavior of the fluid to achieve absolute data using a parallel-plate measuring system. The ability for representing
different behaviors along the entire shear-rate range makes this method particularly interesting for the study of magnetorheological
(MR) fluids. In this work, the conversion factors used by the rheometer for concentric-cylinder, cone-plate, and parallel-plate
measuring systems are first analyzed. This analysis shows that the software used by the rheometer is not appropriate for the
quantitative characterization of non-Newtonian fluids using the parallel-plate measuring system. Therefore, a new method for
conversion of the parameters measured by the rheometer to the rheological parameters of the fluid is proposed; simultaneously,
this new method is compared with other correction methods proposed in the literature: the Rabinowitsch-type method and the
single-point method. Finally, the proposed method is applied for the quantitative characterization of an MR fluid. 相似文献
99.
100.
Masao Fukushima Mounir Haddou Hien Van Nguyen Jean-Jacques Strodiot Takanobu Sugimoto Eiki Yamakawa 《Computational Optimization and Applications》1996,5(1):5-37
In this paper, we propose a parallel decomposition algorithm for solving a class of convex optimization problems, which is broad enough to contain ordinary convex programming problems with a strongly convex objective function. The algorithm is a variant of the trust region method applied to the Fenchel dual of the given problem. We prove global convergence of the algorithm and report some computational experience with the proposed algorithm on the Connection Machine Model CM-5. 相似文献