Thermal Stress Modeling of the Freezing of Biological Tissue

1999 ◽  
Author(s):  
Yoed Rabin ◽  
Paul S. Steif
Keyword(s):  
Phase Transition ◽  
Biological Tissues ◽  
Mechanical Stresses ◽  
Temperature Gradients ◽  
Freezing Process ◽  
Freezing Front ◽  
Ongoing Research ◽  
Mechanical Boundary Condition ◽  
Repeated Freezing ◽  
Thawing Rate

Abstract The extent of injury of biological tissues by freezing is influenced by many factors such as the cooling rate, the thawing rate, the minimal temperature achieved, the number of repeated freezing thawing cycles, and the presence of cryoprotectants. The mechanisms of cryo-destruction may generally be separated into two groups; the first is related to the freezing process within the phase transition temperature range (typically between 0 and −22°C), while the second group is related to further destruction after phase transition has completed. Destruction mechanisms of the first group are related to heat transfer, mass transfer, and chemical equilibrium in the intracellular and extracellular solutions. Destruction mechanisms after the phase transition has been completed are related to mechanical stresses in the frozen state. Mechanical stresses develop when changes in density occur nonuniformly in the tissue, a consequence of the presence of temperature gradients. The current presentation gives an up-to-date report on ongoing research to model the freezing of biological tissues and to measure their physical properties. The mechanical boundary condition at the freezing front is emphasized in this presentation, and examples for typical cases of cryosurgery and cryopreservation are discussed.

Combined Solution of the Inverse Stefan Problem for Successive Freezing/Thawing in Nonideal Biological Tissues

1997 ◽  
Vol 119 (2) ◽  
pp. 146-152 ◽  
Author(s):  
Y. Rabin ◽  
A. Shitzer
Keyword(s):  
Phase Transition ◽  
Heat Generation ◽  
Thermal Effects ◽  
Blood Perfusion ◽  
Biological Tissues ◽  
Initial Condition ◽  
Freezing Front ◽  
Metabolic Heat ◽  
Metabolic Heat Generation ◽  
Combined Solution

A new combined solution of the one-dimensional inverse Stefan problem in biological tissues is presented. The tissue is assumed to be a nonideal material in which phase transition occurs over a temperature range. The solution includes the thermal effects of blood perfusion and metabolic heat generation. The analysis combines a heat balance integral solution in the frozen region and a numerical enthalpy-based solution approach in the unfrozen region. The subregion of phase transition is included in the unfrozen region. Thermal effects of blood perfusion and metabolic heat generation are assumed to be temperature dependent and present in the unfrozen region only. An arbitrary initial condition is assumed that renders the solution useful for cryosurgical applications employing repeated freezing/thawing cycles. Very good agreement is obtained between the combined and an exact solution of a similar problem with constant thermophysical properties and a uniform initial condition. The solution indicated that blood perfusion does not appreciably affect either the shape of the temperature forcing function on the cryoprobe or the location and depth of penetration of the freezing front in peripheral tissues. It does, however, have a major influence on the freezing/thawing cycle duration, which is most pronounced during the thawing stage. The cooling rate imposed at the freezing front also has a major inverse effect on the duration of the freezing/thawing.

scholarly journals Experimental Study on Freeze-Thaw Cycle Duration of Saturated Tuff

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Man Huang ◽  
Bin Tang ◽  
Jianliang Jiang ◽  
Renqiu Guan ◽  
Huajun Wang
Keyword(s):  
Phase Transition ◽  
Power Function ◽  
Melting Process ◽  
Freezing Process ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Initial Melting ◽  
Time Required ◽  
Ice Water

The freeze-thaw duration is one of the important factors affecting the change of rock properties. However, this factor has not formed a unified standard in the freeze-thaw cycle test. This study uses saturated tuff samples taken from eastern Zhejiang, China, as research objects to explore the change law of the time required for the rock to reach a full freeze-thaw cycle. Measured results show that the total duration of the freeze-thaw cycle presents an increasing power function with the increase in the number of freeze-thaw cycles. The freezing process is divided into three phases: initial freezing, water-ice phase transition, and deep freezing. The melting process is also divided into three phases: initial melting, ice-water phase transition, and deep melting. The time required for the ice-water phase change stage of the melting process does not change with the increase in the number of freeze-thaw cycles, while the other stages increase as a power function. The proportion of duration of each stage in the freezing process does not change with the increase in the number of cycles. By contrast, the duration proportion of the initial melting phase in the melting process decreases, and the deep melting phase increases. Experimental results of the freeze-thaw cycles of tuff demonstrate that the freeze-thaw duration of the freeze-thaw cycles within 40 times can be set to 9 h. The freezing and melting processes are 6 and 3 h, respectively.

scholarly journals Variation of thermal conductivity of DPPC lipid bilayer membranes around the phase transition temperature

2017 ◽  
Vol 14 (130) ◽  
pp. 20170127 ◽  
Author(s):  
Sina Youssefian ◽  
Nima Rahbar ◽  
Christopher R. Lambert ◽  
Steven Van Dessel
Keyword(s):  
Phase Transition ◽  
Thermal Conductivity ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Lipid Bilayer ◽  
Lipid Bilayers ◽  
Phase Transition Temperature ◽  
Temperature Gradients ◽  
Phase Behaviour ◽  
Gel Phase

Given their amphiphilic nature and chemical structure, phospholipids exhibit a strong thermotropic and lyotropic phase behaviour in an aqueous environment. Around the phase transition temperature, phospholipids transform from a gel-like state to a fluid crystalline structure. In this transition, many key characteristics of the lipid bilayers such as structure and thermal properties alter. In this study, we employed atomistic simulation techniques to study the structure and underlying mechanisms of heat transfer in dipalmitoylphosphatidylcholine (DPPC) lipid bilayers around the fluid–gel phase transformation. To investigate this phenomenon, we performed non-equilibrium molecular dynamics simulations for a range of different temperature gradients. The results show that the thermal properties of the DPPC bilayer are highly dependent on the temperature gradient. Higher temperature gradients cause an increase in the thermal conductivity of the DPPC lipid bilayer. We also found that the thermal conductivity of DPPC is lowest at the transition temperature whereby one lipid leaflet is in the gel phase and the other is in the liquid crystalline phase. This is essentially related to a growth in thermal resistance between the two leaflets of lipid at the transition temperature. These results provide significant new insights into developing new thermal insulation for engineering applications.

Freezing point and melting point of barnacle muscle fibers

1983 ◽  
Vol 61 (10) ◽  
pp. 1116-1121
Author(s):  
Jean-Pierre Caillé
Keyword(s):  
Phase Transition ◽  
Melting Point ◽  
Structural Component ◽  
Freezing Point ◽  
Muscle Fibers ◽  
Experimental Models ◽  
Freezing Process ◽  
Melting Points ◽  
Intact Muscle ◽  
Barnacle Muscle Fibers

The freezing point and the melting point of myoplasm were measured with two experimental models. In all samples, a supercooled stage was reached by lowering the temperature of the sample to approximately −7 °C, and the freezing of the sample was mechanically induced. The freezing process was associated with a phase transition in the interstices between the contractile filaments. In intact muscle fibers, the freezing point showed a structural component (0.43 °C), and the melting point indicated that the intracellular and the extracellular compartments are isotonic. When the sample of myoplasm, previously inserted in a cylindrical cavity was incubated in an electrolyte solution, the freezing point showed a structural component similar to that of the intact muscle fiber, but the melting point was lower than the freezing and the melting points of the embedding solution. This was interpreted as evidence that the counterions around the contractile filaments occupied a nonnegligible fraction of the intracellular compartment.

Thermodynamic Properties of Water during Phase Transition and Simulation on Freezing Process in Fractured Rock

2011 ◽  
Vol 328-330 ◽  
pp. 9-12 ◽  
Author(s):  
Yong Shui Kang ◽  
Quan Sheng Liu ◽  
Jie Yan
Keyword(s):  
Phase Transition ◽  
Temperature Field ◽  
Stress Field ◽  
Thermodynamic Properties ◽  
Fractured Rock ◽  
Freezing Process ◽  
Thermodynamic Equations

Thermodynamic properties of water during phase transition in fractured rock are discussed. Thermodynamic equations of water in fractured rock while freezing were analyzed, and an example was simulated by FLAC3D. The stress field as well as the temperature field is obtained. The results demonstrated mechanical and thermal influences on rock due to phase transition of water in fractures.

Simulation of Phase Transition During Cryosurgical Treatment of a Tumor Tissue Loaded With Nanoparticles Using Meshfree Approach

2014 ◽  
Vol 136 (12) ◽  
Author(s):  
Sonam Singh ◽  
R. Bhargava
Keyword(s):  
Phase Transition ◽  
Tumor Tissue ◽  
Numerical Technique ◽  
Freezing Process ◽  
Element Free Galerkin Method ◽  
Element Free Galerkin ◽  
Tumor Tissues ◽  
Efficacious Treatment ◽  
Element Free ◽  
Capacity Method

In medical world, the minimally invasive freezing therapy or cryosurgery is an efficacious treatment for complete and controlled eradication of tumor cells. Many difficulties are encountered in cryosurgery process such as inappropriate freezing may not completely destroy the target tumor tissue and excessive freezing may harm the surrounding healthy tissues due to release of high amount of cold from the freezing probe. In present study, the target tumor tissue is loaded with nanoparticles in order to improve the freezing capacity of probe and to regulate the orientation and size of ice-ball formed during cryosurgery. In this process, phase transformation occurs in the undesired tumor tissues. For simulation of phase transition in bio heat transfer equation, the fixed-domain, heat capacity method is used to take into account the latent heat of phase change. In this study, a meshfree numerical technique known as element free Galerkin method (EFGM) is employed to simulate the phase transition and temperature field for a biological tissue subjected to nanocryosurgery. The latest nanofluid model which includes the effects of particles size, concentration, and the interfacial layer at the particle/liquid interface is utilized and their impact on freezing process is investigated in detail.

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