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Search Results: 1 - 10 of 13222 matches for " immiscible systems. "
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STUDY OF THE Fe-75%Ag SYSTEM OBTAINED BY MECHANICAL ALLOYING
Bonyuet,D; González,G; Ochoa,J; Gonzalez-Jimenez,F; D′Onofrio,L;
Revista Latinoamericana de Metalurgia y Materiales , 2002,
Abstract: mechanical alloying (ma) is a powder processing technique, which allows us to induce solid state reactions in binary systems immiscible in equilibrium. fe and ag have a mutually repulsive nature that makes them completely immiscible under thermodynamically stable conditions. the ball milling process being a non-equilibrium technique seems promising in obtaining at least a partial solid solution in this system. mixtures of fe and ag powders with 75 wt% ag were studied by x-ray diffraction (xrd), scanning electron microscopy (sem) and transmission electron microscopy (tem). we have found that it is possible to obtain a small mutual solid solution in this system by ma. this is also confirmed by m?ssbauer spectroscopy.
Síntesis y caracterización de Fe40Ni40Ag20 y (FeNi)80Ag20 mecánicamente aleados
BONYUET,D; GONZáLEZ,G; OCHOA,J; GONZáLEZ-JIMéNEZ,F; D′ONOFRIO,L;
Revista de la Facultad de Ingeniería Universidad Central de Venezuela , 2006,
Abstract: mechanical alloying (ma) is a process that has shown to be a versatile tool to produce nanostructured composites and alloys from normally immiscible elements. it has the advantage that the parameters of the process can be varied in order to control the grade of the alloy and the microstructure characteristics. in this form, it is possible to produce magnetic materials with new properties. the phase diagrams of ni-ag and fe ag show that mutual solubility is very low in the liquid state as in the solid state. however, it has been able to obtain partial solid solutions in these systems by mechanical alloying and other techniques. because the ball milling process is a non equilibrium technique, it is possible to force the mixture of immiscible elements. in this work we present a study of the ternary system fe-ag-ni, preparing by mechanical alloying fe40ni40ag20 and (feni)80ag20 in a spex 8000 mixer/mill. then we characterized the samples by x-ray diffraction (xrd), transmission electron microscopy (tem) and m?ssbauer spectroscopy. the nanometric size grain is confirmed by xrd. m?ssbauer spectroscopy indicates the grade of alloying after different milling times.
STUDY OF THE Fe-75%Ag SYSTEM OBTAINED BY MECHANICAL ALLOYING
D Bonyuet,G González,J Ochoa,F Gonzalez-Jimenez
Revista Latinoamericana de Metalurgia y Materiales , 2002,
Abstract: Mechanical alloying (MA) is a powder processing technique, which allows us to induce solid state reactions in binary systems immiscible in equilibrium. Fe and Ag have a mutually repulsive nature that makes them completely immiscible under thermodynamically stable conditions. The ball milling process being a non-equilibrium technique seems promising in obtaining at least a partial solid solution in this system. Mixtures of Fe and Ag powders with 75 wt% Ag were studied by x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). We have found that it is possible to obtain a small mutual solid solution in this system by MA. This is also confirmed by M ssbauer spectroscopy. Aleación Mecánica (AM) es una técnica de procesamiento de polvos, la cual nos permite inducir reacciones de estado sólido en sistemas binarios inmiscibles en el equilibrio. Fe y Ag tienen una naturaleza mutuamente repulsiva que las hace completamente inmiscibles bajo condiciones termodinámicamente estables. El proceso de molienda por bolas, siendo una técnica fuera del equilibrio, parece prometedor para obtener al menos una solución sólida parcial en este sistema. Mezclas de polvos de Fe y Ag con 75 % en peso de Ag fueron estudiados mediante difracción de rayos x (DRX), microscopía electrónica de barrido (MEB), y microscopía electrónica de transmisión (MET). Hemos encontrado que es posible obtener una peque a solución sólida parcial en este sistema mediante AM. Esto es confirmado mediante espectroscopia M ssbauer.
Rheological Properties of Polymers: Structure and Morphology of Molten Polymer Blends  [PDF]
Oluranti Sadiku-Agboola, Emmauel Rotimi Sadiku, Adesola Taoreed Adegbola, Olusesan Frank Biotidara
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.21005
Abstract: The article reviews a brief literature on the rheological properties of polymer melts and blends. Experimental results on polymer blends are summarized. Technically, vital types of multi-phase polymers such as compounds and blends are discussed. The importance of the rheological properties of polymer mixtures in the development of the phase structure is discussed. And the importance of considering the stress and/or strain history of a material sample in a rheological investigation is discussed. Finally, the outlook on the past, present and future developments in the field of polymer rheology are given. The review concludes with a brief discussion on the opportunities and challenges in the field of polymer blends and blend rheology.
Pressure/Saturation System for Immiscible Two-Phase Flow: Uniqueness Revisited  [PDF]
Koffi B. Fadimba
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.25071
Abstract: We give a sufficient condition for uniqueness for the pressure/saturation system. We establish this condition through analytic arguments, and then construct "mobilities" (or mobility-like functions) that satisfy the new condition (when the parameter is 2). For the constructed "mobilities", we do graphical experiments that show, empirically, that this condition could be satisfied for other values of . These empirical experiments indicate that the usual smoothness condition on the fractional flow function (and on the total mobility), for uniqueness and convergence, might not be necessary. This condition is also sufficient for the convergence of a family of perturbed problems to the original pressure/saturation problem.
LATTICE BOLTZMANN METHOD SIMULATION ON THE FLOW OF TWO IMMISCIBLE FLUIDS IN COMPLEX GEOMETRY

Fang Hai-ping,Wan Rong-zheng,Fan Le-wen,

中国物理 B , 2000,
Abstract:
Cuette flow of two immiscible fluids between two permeable beds
T. V. A. P. Sastry,M. Venkata Krishna,S. Sreenadh,M. V. Ramanamurthy
Journal of Engineering and Applied Sciences , 2010,
Abstract: Couette flow of two viscous, incompressible, immiscible fluids in a channel bounded by permeable beds is investigated. The lower bed is of finite thickness with high permeability and the upper bed is of infinite thickness with low permeability. The flow in the lower permeable bed is described by Brinkman equation whereas the flow in the upper permeable bed is described by Darcy’s law. The flow between the two beds is governed by Navier-Stokes equations. The velocity field and the mass flow rate are obtained. It is observed that the velocity is in increasing trend with the increment in the Reynolds number.
Mhd flow and heat transfer of two immiscible fluids with induced magnetic field effects
Stamenkovi? ?ivojin M.,Nikodijevi? Dragi?a D.,Koci? Milo? M.,Nikodijevi? Jelena D.
Thermal Science , 2012, DOI: 10.2298/tsci120430172s
Abstract: The paper investigates the magnetohydrodynamic flow of two immiscible, electrically conducting fluids between isothermal and insulated moving plates in the presence of an applied electric and inclined magnetic field with the effects of induced magnetic field. Partial differential equations governing the flow and heat transfer and magnetic field conservation are transformed to ordinary differential equations and solved exactly in both fluid regions, under physically appropriate boundary and interface conditions. Closed-form expressions are obtained for the non-dimensional velocity, non-dimensional induced magnetic field and nondimensional temperature. The analytical results for various values of the Hartmann number, the angle of magnetic field inclination, loading parameter and the ratio of plates’ velocities are presented graphically to show their effect on the flow and heat transfer characteristics. [Projekat Ministarstva nauke Republike Srbije, br. TR 35016]
Laboratory Experiments on Enhanced Oil Recovery with Nitrogen Injection
S. Siregar,A. D. Hidayaturobbi,B. A. Wijaya,S.N. Listiani
ITB Journal of Engineering Science , 2007,
Abstract: Based on previous studies, nitrogen injection could recover oil up to 45-90% of initial reserves. Although this method has a very good ability to produce oil, sometimes the operation pressure is higher than leak off formation pressure. In this study, operation pressure used a low pressure to solve this problem under immiscible process. Objective of this study is to determine the effect of injection pressure and displacement rate on oil recovery performance of continuous one dimensional nitrogen gas injection with a slim tube apparatus. The effect of nitrogen gas-oil contact on the gas composition was investigated using Gas Chromatograph Mass Spectrometer apparatus. In the experiments, nitrogen gas was injected into an oil sample of 38.5 oAPI gravity at various rates: 20 cc/hr, 30 cc/hr and 36.66/hr under 1500 psi pressure, and then at 20 cc/hr undr 2500 psi pressure. The results showed that an increase in injection rate increased oil recovery factor. The recovery factor lies between 40-54% of original oil in place. Gas analysis before injection and at the injection outlet showed a change of composition. when oil was contacted by nitrogen, indicating that some molecular mass transfer had taken place.
Transient Magnetohydrodynamic flow of two immiscible Fluids through a horizontal channe
Abdul Mateen
International Journal of Engineering Research , 2014,
Abstract: An analysis is made for transient Magnetohydrodynamic (MHD) flow of two immiscible fluids thorough a horizontal channel. The flow above the interface is assumed to be electrically conducting while the other fluid and the channel walls are assumed to be electrically insulating. The partial differential equations governing the flow are solved analytically using two-term periodic and non-periodic functions in both the regions of the channels. Velocity profiles are analyzed for various physical parameters such as viscosity ratio, frequency parameter and Hartmann number.
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