The issue of switching between non-freezing and freezing in soils

2020 ◽  
Author(s):  
Johanna Blöcher ◽  
Michal Kuraz
Keyword(s):  
Freezing Point ◽  
Pressure Head ◽  
Important Variable ◽  
Freezing Process ◽  
Total Water ◽  
Temperature Dependent ◽  
Freezing Front ◽  
Soil System ◽  
Clapeyron Equation ◽  
Natural Systems

<p>The freezing process in soils is important in many natural systems and, consequently, it is of great interest to model it accurately. <br>The freezing of water in soil is coupled to the heat equation as freezing releases latent heat and temperature is an important variable that determines whether water is in solid or liquid state. In soils, water can remain liquid under sub-zero temperatures (freezing-point depression). This effect is often modeled with the Clapeyron equation. With the Clapeyron equation, a temperature dependent pressure head definition for the total water content (liquid + frozen water) and the liquid water can be derived. When the temperature of the soil system falls below the freezing point, the system switches between the pressure head definitions. However, this switch can cause a discontinuity at the freezing front leading to numerical issues and unrealistic results.</p><p>To compensate for the discontinuity, we discuss the use of regularisation of the switching term on, both, synthetic and experimental data of case studies of freezing column experiments. </p>

Textural and mineralogical controls on temperature dependent SIP behavior during freezing and thawing

2021 ◽  
Author(s):  
Jonas K. Limbrock ◽  
Maximilian Weigand ◽  
Andreas Kemna
Keyword(s):  
Freezing Point ◽  
Pore Space ◽  
Thermal Characterization ◽  
Complex Frequency ◽  
Freezing And Thawing ◽  
Temperature Dependent ◽  
Measured Resistance ◽  
Ice Content ◽  
Water Saturated ◽  
Geoelectrical Methods

<p>Geoelectrical methods are increasingly being used for non-invasive characterization and monitoring of permafrost sites, since the electrical properties are sensitive to the phase change of liquid to frozen water. Here, electrical resistivity tomography (ERT) is most commonly applied, using resistivity as a proxy for various quantities, such as temperature or ice content. However, it is still challenging to distinguish between air and ice in the pore space of the rock based on resistivity alone due to their similarly low electrical conductivity. Meanwhile, geoelectrical methods that utilize electrical polarization effects to characterize permafrost are also being explored. For example, the usage of the spectral induced polarization (SIP) method, in which the complex, frequency-dependent impedance is measured, can reduce ambiguities in the subsurface conduction properties, considering the SIP signature of ice. These measurements seem to be suitable for the quantification of ice content (and thus the differentiation of ice and air), and for the improved thermal characterization of alpine permafrost sites. However, to improve the interpretation of SIP measurements, it is necessary to understand in more detail the electrical conduction and polarization properties as a function of temperature, ice content, texture, and mineralogy under frozen and partially frozen conditions.</p><p>In the study presented here, electrical impedance was measured continuously using SIP in the frequency range of 10 mHz to 45 kHz on various water-saturated solid rock and loose sediment samples during controlled freeze-thaw cycles (+20°C to -40°C). These measurements were performed on rock samples from different alpine permafrost sites with different mineralogical compositions and textures. For all samples, the resistance (impedance magnitude) shows a similar temperature dependence, with increasing resistance for decreasing temperature. Also, hysteresis between freezing and thawing behavior is observed for all measurements. During freezing, a jump within the temperature-dependent resistance is observed, suggesting a lowering of the freezing point to a critical temperature where an abrupt transition from liquid water to ice occurs. During thawing, on the other hand, there is a continuous decrease in the measured resistance, suggesting a continuous thawing of the sample. The spectra of impedance phase, which is a measure for the polarization, exhibit the same qualitative, well-known temperature-dependent relaxation behaviour of ice at higher frequencies (1 kHz - 45 kHz), with variations in shape and strength for different rock texture and mineralogy. At lower frequencies (1 Hz - 1 kHz), a polarization with a weak frequency dependence is observed in the unfrozen state of the samples. We interpret this response as membrane polarization, which likewise depends on the texture as well as on the mineralogy of the respective sample. This polarization response partially vanishes during freezing. Overall, the investigated SIP spectra do not only show a dependence on texture and mineralogy, but mainly a dependence on the presence of ice in the sample as well as temperature. This indicates the possibility of a thermal characterization, as well as a determination of the ice content, of permafrost rocks using SIP.</p>

Thermodynamic Theory and Experimental Validation of a Multiphase Isochoric Freezing Process

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Matthew J. Powell-Palm ◽  
Justin Aruda ◽  
Boris Rubinsky
Keyword(s):  
First Principles ◽  
Experimental Validation ◽  
Freezing Point ◽  
Physiological Saline ◽  
Physiological Solution ◽  
Freezing Process ◽  
Hypertonic Solution ◽  
Chemical Additives ◽  
Biological Matter ◽  
High Concentrations

Freezing of the aqueous solutions that comprise biological materials, such as isotonic physiological saline, results in the formation of ice crystals and the generation of a hypertonic solution, both of which prove deleterious to biological matter. The field of modern cryopreservation, or preservation of biological matter at subfreezing temperatures, emerged from the 1948 discovery that certain chemical additives such as glycerol, known as cryoprotectants, can protect cells from freeze-related damage by depressing the freezing point of water in solution. This gave rise to a slew of important medical applications, from the preservation of sperm and blood cells to the recent preservation of an entire liver, and current cryopreservation protocols thus rely heavily on the use of additive cryoprotectants. However, high concentrations of cryoprotectants themselves prove toxic to cells, and thus there is an ongoing effort to minimize cryoprotectant usage while maintaining protection from ice-related damage. Herein, we conceive from first principles a new, purely thermodynamic method to eliminate ice formation and hypertonicity during the freezing of a physiological solution: multiphase isochoric freezing. We develop a comprehensive thermodynamic model to predict the equilibrium behaviors of multiphase isochoric systems of arbitrary composition and validate these concepts experimentally in a simple device with no moving parts, providing a baseline from which to design tailored cryopreservation protocols using the multiphase isochoric technique.

Freezing Point Determination in Immature Stages of Insects

1964 ◽  
Vol 96 (1-2) ◽  
pp. 158-158 ◽  
Author(s):  
C. R. Sullivan ◽  
G. W. Green
Keyword(s):  
Cold Hardiness ◽  
Freezing Point ◽  
Visual Observation ◽  
Freezing Process ◽  
Immature Stages ◽  
Filter Paper Disc ◽  
Recording Potentiometer ◽  
Binocular Microscope ◽  
The Moment ◽  
Freezing Chamber

Conventional and modified methods of obtaining supercooling points of immature stages of insects have been utilized in studies of the cold-hardiness of the European pine shoot moth and the European pinesawfly. A method has been developed to permit visual observation of the freezing process of more than one specimen at a time. A freezing chamber consisting of a hole one inch in depth and one-half inch in diameter is located in the upper end of an aluminum rod partially submerged in a dry ice-alcohol mixture. A small filter paper disc, used as the insect platform, rests upon a #40 copper-constantan thermocouple located near the base of the freezing chamber. The thermocouple enters the chamber through a hole in the wall after several circuits around the circumference of the rod to prevent temperature anomalies attributable to thermal conduction within the wire. The thermocouple is connected to a sensitive recording potentiometer. The wall of the freezing chamber is blackened to prevent reflection of light from obscuring the view of the freezing process, through a binocular microscope mounted above the freezing chamber. The moment of freezing is readily recorded on the temperature trace provided by the potentiometer. At a cooling rate of approximately 5°F. per minute, a correction factor of 2.5°F. must be added to the indicated freezing point to obtain the actual temperature at the surface of the platform. When this correction is applied, the results provide data applicable to statistical analysis of freezing point determinations.

scholarly journals IPA (V1): A framework for agent-based modelling of soil water movement

2018 ◽  
Author(s):  
Benjamin Mewes ◽  
Andreas H. Schumann
Keyword(s):  
Water Movement ◽  
Soil Column ◽  
Nonlinear Behaviour ◽  
Soil System ◽  
New Approach ◽  
Agent Based ◽  
Natural Systems ◽  
Agent Based Modelling ◽  
Current State ◽  
Physical Laws

Abstract. In the last decade, agent-based modelling (ABM) became a popular modelling technique in social sciences, medicine, biology and ecology. ABM was designed to simulate systems that are highly dynamic and sensitive to small variations in their composition and their state. As hydrological systems, and natural systems in general, often show dynamic and nonlinear behaviour, ABM can be an appropriate way to model these systems. Nevertheless, only few studies have utilized ABM method for process-based modelling in hydrology. The percolation of water through the unsaturated soil is highly responsive to the current state of the soil system, small variations in composition lead to major changes in the transport system. Hence, we present a new approach for modelling the movement of water through a soil column: autonomous water agents that transport water through the soil while interacting with their environment as well as with other agents under physical laws.

scholarly journals Generalized enthalpy model of a high-pressure shift freezing process

2012 ◽  
Vol 468 (2145) ◽  
pp. 2744-2766 ◽  
Author(s):  
Nadia A. S. Smith ◽  
Stephen S. L. Peppin ◽  
Ángel M. Ramos
Keyword(s):  
High Pressure ◽  
Stokes Equations ◽  
Freezing Point ◽  
Food Samples ◽  
Navier Stokes ◽  
Freezing Process ◽  
Frozen Foods ◽  
Navier Stokes Equations ◽  
Pressure Shift ◽  
Pressure Shift Freezing

High-pressure freezing processes are a novel emerging technology in food processing, offering significant improvements to the quality of frozen foods. To be able to simulate plateau times and thermal history under different conditions, in this work, we present a generalized enthalpy model of the high-pressure shift freezing process. The model includes the effects of pressure on conservation of enthalpy and incorporates the freezing point depression of non-dilute food samples. In addition, the significant heat-transfer effects of convection in the pressurizing medium are accounted for by solving the two-dimensional Navier–Stokes equations. We run the model for several numerical tests where the food sample is agar gel, and find good agreement with experimental data from the literature.

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.

In situ measurements of moisture and salt movement in freezing soils

1986 ◽  
Vol 23 (5) ◽  
pp. 696-704 ◽  
Author(s):  
D. M. Gray ◽  
R. J. Granger
Keyword(s):  
Soil Moisture ◽  
Moisture Transfer ◽  
Freezing Point ◽  
Frozen Soil ◽  
Vapor Flow ◽  
Silty Clay ◽  
Upward Movement ◽  
Silt Loam ◽  
Freezing Front ◽  
Ice Content

The paper presents the results of field studies on the movement of moisture and salts during freezing of Prairie soils. It is shown that large fluxes of water can migrate to the freezing front and move upward into the frozen soil above. The fluxes are largest in light-textured soils (e.g., silt loam) having a water table at shallow depth. However, substantial amounts of soil moisture may also move in silty clay, silty clay loam, and clay soils under dryland farming provided there is sufficient water present to support capillary flow.The dynamics of soil moisture transfer under natural conditions as a result of freezing involves movement of water in both vapor and liquid phases. In the shallow surface layer of soil, to a depth of 300–400 mm, vapor flow predominates; in the depth below, water usually moves primarily as a liquid. It is demonstrated that the accumulation of ice with time increases because of the downward movement of the freezing front and the upward movement of water into the frozen soil above. In a silt loam with large fluxes, the ice content of the frozen zone rapidly reaches a level (80–85% pore saturation) where measurable migration ceases. Conversely, in a silty clay the movement of moisture into the frozen soil is observed to continue throughout most of the freezing period, and the ice content reaches 93% pore saturation. The greater movement in the finer grained soil is attributed to a higher freezing-point depression, a larger number of capillary pores, and a higher concentration of soluble salts in the liquid films.A close association is observed between changes in the ice content and electrical conductivity of a silt loam after freezing. In a silty clay the agreement is less clear, probably the result of the exchange of ions between the migrating liquid water and the clay particles. Maximum amounts of exchangeable ions moving into a 1 m depth of soil by the freezing action are estimated to be 11.9 t/ha in a silt loam and 15.7 t/ha in a silty clay loam.Data showing the redistribution of water and salts during thawing are also presented and discussed.

scholarly journals Modeling radiocarbon dynamics in soils: SoilR version 1.1

2014 ◽  
Vol 7 (3) ◽  
pp. 3161-3192 ◽  
Author(s):  
C. A. Sierra ◽  
M. Müller ◽  
S. E. Trumbore
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Transit Time ◽  
Mean Transit Time ◽  
Time Data ◽  
Soil System ◽  
Linear Dynamical Systems ◽  
Natural Systems ◽  
Radiocarbon Data ◽  
The Mean

Abstract. Radiocarbon is an important tracer of the global carbon cycle that helps to understand carbon dynamics in soils. It is useful to estimate rates of organic matter cycling as well as the mean residence or transit time of carbon in soils. We included a set of functions to model the fate of radiocarbon in soil organic matter within the SoilR package for the R environment for computing. Here we present the main system equations and functions to calculate the transfer and release of radiocarbon from different soil organic matter pools. Similarly, we present functions to calculate the mean transit time for different pools and the entire soil system. This new version of SoilR also includes a group of datasets describing the amount of radiocarbon in the atmosphere over time, data necessary to estimate the incorporation of radiocarbon in soils. Also, we present examples on how to obtain parameters of pool-based models from radiocarbon data using inverse parameter estimation. This implementation is general enough so it can also be used to trace the incorporation of radiocarbon in other natural systems that can be represented as linear dynamical systems.

scholarly journals Modeling the Influence of Temperature-dependent Thermal Properties on the Freezing Front

2019 ◽  
Vol 8 (6) ◽  
pp. 129
Author(s):  
Victor M. Chavarria
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Statistical Error ◽  
Analytical Models ◽  
Parameter Estimates ◽  
Temperature Dependent ◽  
Freezing Front ◽  
Model Accuracy ◽  
Medium Temperature ◽  
Wide Range

Although numerical methods enable comprehensive analyses of food freezing, a thorough quantification is lacking the effects on the process introduced by uncertainties in variable thermal properties. Analytical models are, however, more suitable tools to perform such calculations. We aim to quantify these effects by developing a solution to the freezing front (FF) problem subject to temperature-dependent thermal properties and one-dimensional convective cooling. The heat integral balance method, Kirchhoff's transformation, and Plank's cooled-surface temperature equation (as a seed function) enabled us to obtain an approximate solution to the FF penetration time. To optimize model accuracy, two adjustable parameters were correlated with the inputs via nonlinear regression referenced to numerical simulation FF data. The mapped sensitivities, generated by perturbations in the temperature-dependent thermal conductivity and effective heat capacity, undergo rapid nonlinear changes for Biot numbers below 6. Above this level, these sensitivities stabilize depending on the cooling medium temperature and a thermal conductivity parameter. The median thermal conductivity-driven sensitivity is 0.348 and its interquartile range (IQR) is 0.220 to 0.425, whereas the median latent heat-driven sensitivity is 0.967 (IQR: 0.877 to 0.985). Statistical error measures and a ten-split K-fold validation support the model accuracy and reliability of the parameter estimates. Together, the model allows for gaining insights into the nonlinear behavior and magnitude of the influence of variable properties on the FF for a wide range of conditions. Nonlinear methods and prior information enable practical modeling of transport phenomena in foods.

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.

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