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Full-Text Articles in Engineering
A Two-Temperature Model For Selective Photothermolysis Laser Treatment Of Port Wine Stains, D. Li, Guo-Xiang Wang, Y. He, K. Kelly, W. Wu, Y. Wang, Z. Ying
A Two-Temperature Model For Selective Photothermolysis Laser Treatment Of Port Wine Stains, D. Li, Guo-Xiang Wang, Y. He, K. Kelly, W. Wu, Y. Wang, Z. Ying
Dr. Guo-Xiang Wang
Selective photothermolysis is the basic principle for laser treatment of vascular malformations such as port wine stain birthmarks (PWS). During cutaneous laser surgery, blood inside blood vessels is heated due to selective absorption of laser energy, while the surrounding normal tissue is spared. As a result, the blood and the surrounding tissue experience a local thermodynamic non-equilibrium condition. Traditionally, the PWS laser treatment process was simulated by a discrete-blood-vessel model that simplifies blood vessels into parallel cylinders buried in a multi-layer skin model. In this paper, PWS skin is treated as a porous medium made of tissue matrix and blood …
A Three-Temperature Model Of Selective Photothermolysis For Laser Treatment Of Port Wine Stain Containing Large Malformed Blood Vessels, D. Li, Guo-Xiang Wang, Y. He, W. Wu, B. Chen
A Three-Temperature Model Of Selective Photothermolysis For Laser Treatment Of Port Wine Stain Containing Large Malformed Blood Vessels, D. Li, Guo-Xiang Wang, Y. He, W. Wu, B. Chen
Dr. Guo-Xiang Wang
As congenital vascular malformations, port wine stain (PWS) is composed of ectatic venular capillary blood vessels buried within healthy dermis. In clinic, pulsed dye laser (PDL) in visible band (e.g. 585 nm) together with cryogen spray cooling (CSC) have become the golden standard for treatment of PWS. However, due to the limited energy deposition of the PDL in blood, large blood vessels are likely to survive from the laser irradiation. As a result, complete clearance of the lesions is rarely achieved. Assuming the local thermal non-equilibrium in skin tissue during the laser surgery, a three-temperature model is proposed to treat …
Theoretical Modelling Of Momentum Transfer Function Of Bi-Disperse Porous Media
Theoretical Modelling Of Momentum Transfer Function Of Bi-Disperse Porous Media
Faculty of Engineering University of Malaya
The aim of this paper is to obtain the momentum transfer coefficient between the two phases, denoted by f and p, occupying a bi-disperse porous medium by mapping the available experimental data to the theoretical model proposed by Nield and Kuznetsov [1]. Data pertinent to plate-fin heat exchangers, as bi-disperse porous media, were used. The measured pressure drops for such heat exchangers are then used to give the overall permeability which is linked to the porosity and permeability of each phase as well as the interfacial momentum transfer coefficient between the two phases. Accordingly, numerical values are obtained for the …
Validity Of The One-Dimensional Limp Model For Porous Media, Olivier Doutres, Nicolas Dauchez, Jean-Michel Génevaux, Olivier Dazel
Validity Of The One-Dimensional Limp Model For Porous Media, Olivier Doutres, Nicolas Dauchez, Jean-Michel Génevaux, Olivier Dazel
Olivier Doutres Ph.D.
A straightforward criterion for determining the validity of the limp model validity for porous materials is addressed here. The limp model is an “equivalent fluid” model which gives a better description of porous behavior than the well known “rigid frame” model. It is derived from the poroelastic Biot model, assuming that the frame has no bulk stiffness. A criterion is proposed for identifying the porous materials for which the limp model can be used. It relies on a new parameter, the Frame Stiffness Influence FSI, based on porous material properties. The critical values of FSI under which the limp model …