Open Access. Powered by Scholars. Published by Universities.®

Physics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 8 of 8

Full-Text Articles in Physics

On The Transition From Diffusion-Limited To Kinetic-Limited Regimes Of Alloy Solidification, Sergey Sobolev Oct 2013

On The Transition From Diffusion-Limited To Kinetic-Limited Regimes Of Alloy Solidification, Sergey Sobolev

Sergey Sobolev

An abrupt transition from diffusion-limited solidification to diffusionless, kinetic-limited solidification with complete solute trapping is explained as a critical phenomenon which arises due to local non-equilibrium diffusion effects in the bulk liquid. The transition occurs when the interface velocityVpasses through the critical pointV=VD, where V=VDis the bulk liquid diffusive velocity. Analytical expressions are developed for velocity–temperature and velocity–undercooling functions, using local non-equilibrium partition coeffi-cient based on the Jackson et al. kinetic model and the local non-equilibrium diffusion model of Sobolev. The calculated functions dem-onstrate a sharp break in the velocity–undercooling and velocity–temperature relationships at the critical pointV=VD. At this point …


Laminar Flow Of Two Miscible Fluids In A Simple Network, Casey Karst, Brian Storey, John B. Geddes Sep 2013

Laminar Flow Of Two Miscible Fluids In A Simple Network, Casey Karst, Brian Storey, John B. Geddes

Brian Storey

When a fluid comprised of multiple phases or constituents flows through a network, nonlinear phenomena such as multiple stable equilibrium states and spontaneous oscillations can occur. Such behavior has been observed or predicted in a number of networks including the flow of blood through the microcirculation, the flow of picoliter droplets through microfluidic devices, the flow of magma through lava tubes, and two-phase flow in refrigeration systems. While the existence of nonlinear phenomena in a network with many inter-connections containing fluids with complex rheology may seem unsurprising, this paper demonstrates that even simple networks containing Newtonian fluids in laminar flow …


Systems Of Navier-Stokes Equations On Cantor Sets Jun 2013

Systems Of Navier-Stokes Equations On Cantor Sets

Xiao-Jun Yang

We present systems of Navier-Stokes equations on Cantor sets, which are described by the local fractional vector calculus. It is shown that the results for Navier-Stokes equations in a fractal bounded domain are efficient and accurate for describing fluid flow in fractal media.


Laminar Flow Of Two Miscible Fluids In A Simple Network, Casey Karst, Brian Storey, John Geddes Mar 2013

Laminar Flow Of Two Miscible Fluids In A Simple Network, Casey Karst, Brian Storey, John Geddes

John B. Geddes

When a fluid comprised of multiple phases or constituents flows through a network, nonlinear phenomena such as multiple stable equilibrium states and spontaneous oscillations can occur. Such behavior has been observed or predicted in a number of networks including the flow of blood through the microcirculation, the flow of picoliter droplets through microfluidic devices, the flow of magma through lava tubes, and two-phase flow in refrigeration systems. While the existence of nonlinear phenomena in a network with many inter-connections containing fluids with complex rheology may seem unsurprising, this paper demonstrates that even simple networks containing Newtonian fluids in laminar flow …


Local Nonequilibrium Solute Trapping Model For Non-Planar Interface, Sergey Sobolev Jan 2013

Local Nonequilibrium Solute Trapping Model For Non-Planar Interface, Sergey Sobolev

Sergey Sobolev

A generalized solute trapping model was proposed incorporating the dependency on interfacial normal velocity along the dendrite side, as an extension of the continuous growth model modified by Sobolev with the local nonequilibrium diffusion model (LNDM). The present model predicts that the transition to diffusionless solidification is not sharp, but occurs in a range of velocities. Analysis indicates that for local nonequilibrium solute diffusion in bulk liquid the effect of the interfacial normal velocity dependency on solute partitioning is considerable.


Mechaniczny Rozdział Faz Proj., Wojciech M. Budzianowski Jan 2013

Mechaniczny Rozdział Faz Proj., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.


Challenges And Prospects Of Processes Utilising Carbonic Anhydrase For Co2 Separation, Patrycja Szeligiewicz, Wojciech M. Budzianowski Jan 2013

Challenges And Prospects Of Processes Utilising Carbonic Anhydrase For Co2 Separation, Patrycja Szeligiewicz, Wojciech M. Budzianowski

Wojciech Budzianowski

This article provides an analysis of processes for separation CO2 by using carbonic anhydrase enzyme with particular emphasis on reactive-membrane solutions. Three available processes are characterised. Main challenges and prospects are given. It is found that in view of numerous challenges practical applications of these processes will be difficult in near future. Further research is therefore needed for improving existing processes through finding methods for eliminating their main drawbacks such as short lifetime of carbonic anhydrase or low resistance of reactive membrane systems to impurities contained in flue gases from power plants.


Determination Of Kinetic Parameters From The Thermogravimetric Data Set Of Biomass Samples, Karol Postawa, Wojciech M. Budzianowski Dec 2012

Determination Of Kinetic Parameters From The Thermogravimetric Data Set Of Biomass Samples, Karol Postawa, Wojciech M. Budzianowski

Wojciech Budzianowski

This article describes methods of the determination of kinetic parameters from the thermogravimetric data set of biomass samples. It presents the methodology of the research, description of the needed equipment, and the method of analysis of thermogravimetric data. It describes both methodology of obtaining quantitative data such as kinetic parameters as well as of obtaining qualitative data like the composition of biomass. The study is focused mainly on plant biomass because it is easy in harvesting and preparation. Methodology is shown on the sample containing corn stover which is subsequently pyrolysed. The investigated sample show the kinetic of first order …