scholarly journals Freeze/Thaw-Induced Embolism: Probability of Critical Bubble Formation Depends on Speed of Ice Formation

2012 ◽  
Vol 3 ◽  
Author(s):  
Sanna Sevanto ◽  
N. Michele Holbrook ◽  
Marilyn C. Ball
Keyword(s):  
Bubble Formation ◽  
Ice Formation ◽  
Freeze Thaw ◽  
Critical Bubble

A Model of Bubble Nucleation on a Micro Line Heater

1999 ◽  
Vol 121 (1) ◽  
pp. 220-225 ◽  
Author(s):  
S.-D. Oh ◽  
S. S. Seung ◽  
H. Y. Kwak
Keyword(s):  
Bubble Formation ◽  
Three Dimensional ◽  
Bubble Nucleation ◽  
Heat Diffusion ◽  
Nucleation Theory ◽  
Molecular Cluster ◽  
Heater Surface ◽  
Calculation Results ◽  
Critical Bubble ◽  
Superheat Limit

The bubble nucleation mechanism on a cavity-free micro line heater surface was studied by using the molecular cluster model. A finite difference numerical scheme for the three-dimensional transient conduction equation for the liquid was employed to estimate the superheated volume where homogeneous bubble nucleation could occur due to heat diffusion from the heater to the liquid. Calculation results revealed that bubble formation on the heater is possible when the temperature at the hottest point in the heater is greater than the superheat limit of the liquid by 6°C–12°C, which is in agreement with the experimental results. Also it was found that the classical bubble nucleation theory breaks down near the critical point where the radius of the critical bubble is below 100 nm.

scholarly journals Low Salinity and High-Level UV-B Radiation Reduce Single-Cell Activity in Antarctic Sea Ice Bacteria

2009 ◽  
Vol 75 (23) ◽  
pp. 7570-7573 ◽  
Author(s):  
Andrew Martin ◽  
Julie Hall ◽  
Ken Ryan
Keyword(s):  
Sea Ice ◽  
Metabolic Activity ◽  
Cell Activity ◽  
Ice Formation ◽  
Freeze Thaw ◽  
Low Salinity ◽  
Antarctic Sea Ice ◽  
Single Cell Activity ◽  
Fast Ice ◽  
High Level

ABSTRACT Experiments simulating the sea ice cycle were conducted by exposing microbes from Antarctic fast ice to saline and irradiance regimens associated with the freeze-thaw process. In contrast to hypersaline conditions (ice formation), the simulated release of bacteria into hyposaline seawater combined with rapid exposure to increased UV-B radiation significantly reduced metabolic activity.

Human geographies of sea ice: freeze/thaw processes around Cape Dorset, Nunavut, Canada

Polar Record ◽  
2008 ◽  
Vol 44 (1) ◽  
pp. 51-76 ◽  
Author(s):  
Gita J. Laidler ◽  
Pootoogoo Elee
Keyword(s):  
Sea Ice ◽  
Regional Scale ◽  
Open Water ◽  
Current Strength ◽  
Ice Formation ◽  
Future Research ◽  
Baffin Island ◽  
Freeze Thaw ◽  
Ice Conditions ◽  
Inuit Knowledge

ABSTRACTSea ice has been, and continues to be, an integral component of life in the Inuit community of Cape Dorset, Nunavut. Located on an island of the same name off the southwestern coast of Baffin Island, the strong Hudson Strait currents prevent extensive ice formation around the community. Nevertheless, sea ice remains an important travel and hunting platform, enabling access to Baffin Island, hunting and fishing grounds, and nearby communities. With the combined importance, dynamism, and continuous use of this frozen ocean environment, local Inuit elders and hunters have developed a detailed and nuanced understanding of sea ice conditions, freeze/thaw processes, and the influences of winds and currents on ice conditions. Working collaboratively with the community of Cape Dorset since October, 2003, we present the results of 30 semi-directed interviews, 5 sea ice trips, and 2 focus groups to provide a baseline understanding of local freezing processes (near-shore, open water, sea ice thickening, landfast ice, floe edge, and tidal cracks), melting processes (snow melt, water accumulation and drainage, break-up, and cracks/leads), wind influences on sea ice (wind direction and strength affecting sea ice formation, and movement), and current influences on sea ice (tidal variations and current strength affecting sea ice formation, movement, and polynya size/location). Strong emphasis is placed on Inuktitut terminology and spatial delineations of localised ice conditions and features. Therefore, this paper provides insights into local scale ice conditions and dynamics around Cape Dorset that are not captured in regional scale studies of Hudson Bay and/or Hudson Strait. Results have the potential to inform future research efforts on local/regional sea ice monitoring, the relationship between Inuit knowledge, language, and the environment, and addressing community interests through targeted studies.

scholarly journals DURABILITY OF HEAVY CONCRETE USING BOILER SLAGS WITH CIRCULATING FLUIDIZED BED

2018 ◽  
Vol 1 (50) ◽  
pp. 97-103
Author(s):  
V. O. Bondar ◽  
R. R. Akhmednabiyev
Keyword(s):  
Portland Cement ◽  
Fluidized Bed ◽  
Concrete Structure ◽  
Circulating Fluidized Bed ◽  
Ice Formation ◽  
Partial Replacement ◽  
Mathematical Planning ◽  
Ambient Temperatures ◽  
Freeze Thaw ◽  
Crushed Granite

The results of studying the influence of boiler ash slags with a circulating fluidized bed on the freeze-thaw resistance of heavy concretes are presented. The following materials were used in the studies: Portland cement PPC 500 N, sand with the fineness modulus Mf =1.05, crushed granite fraction 5-10 mm, boiler ashes with circulating fluidized bed, hyperplasticizer «Fluid Premia-196». The study was performed using mathematical planning of the experiment. It is proved that with the replacement of sand with ashes, the freeze-thaw resistance is somewhat reduced, but the hyperplasticizer compensates the reduction of freeze-thaw resistance by reducing the W/C ratio, resulting in the formation of super-fine pore structure of concrete. Fine pores in the concrete structure compensate the ice formation stress at low ambient temperatures. The optimal cement consumption has been established in terms of freeze-thaw resistance, both at full and partial replacement of sand with ash. It was also determined that the optimum should be considered the consumption of a hyperplasticizer in the amount of 1.2-1.4% of the cement mass.

Experimental Investigation of Freeze-Thaw Processes in Soils and Grouting Materials

2021 ◽  
Author(s):  
Jan Christopher Hesse ◽  
Jan-Henrik Kupfernagel ◽  
Markus Schedel ◽  
Bastian Welsch ◽  
Lutz Müller ◽  
...  
Keyword(s):  
Porous Media ◽  
P Wave ◽  
Ice Formation ◽  
Unfrozen Water ◽  
Pure Liquid ◽  
Detailed Knowledge ◽  
Strong Impact ◽  
Hydraulic Flow ◽  
Freeze Thaw ◽  
Grouting Materials

<p>Freezing and thawing in the subsurface is often related to complex technical handling of possible influences on the engineered structures (e.g. permafrost or geothermal heat pumps). Freeze-thaw processes in the vicinity of borehole heat exchangers can significantly impair the system. However, for groundwater protection and thermal efficiency, the hydraulic and thermal integrity of such systems must be permanently ensured for the complete operation time. Detailed knowledge on freeze-thaw processes in porous media, such as soils or geotechnical grouts, and the driven parameters, is still pending. Freezing in porous media does not occur as a sudden transition from pure liquid water to the ice phase, but rather within a freezing interval strongly depending on various boundary conditions such as soil type or pore water chemistry. As the content of frozen and unfrozen water has a strong impact on material properties, it is essential to have suitable information about the different factors influencing freezing processes as well as the thermo-hydraulic-mechanical (THM) effects on porous media due to phase change. Thus, a THM laboratory experiment was developed and built to gain more knowledge on freeze-thaw processes and their effects on soil and grouting materials. The experiment consists of a modified triaxial test, enabling for controlled temperature and hydraulic flow conditions, that is combined with an ultrasonic measurement device to determine the unfrozen water content.</p><p>In this contribution, results of the THM experiment are presented, whereas the following parameters were investigated: The freezing interval using P-wave velocity, freezing pressure as well as axial and radial volume expansion due to ice formation as well as the influence of hydraulic flow on the ice formation. First, benchmark experiments were conducted on well-characterized solid rock samples to avoid any influence of a variable sample pore structure during the experiments. Further experiments focused on the investigation of soil samples of different texture classes. For upscaling to real scale applications, the experimental findings will be implemented in numerical models.</p>

Human geographies of sea ice: freeze/thaw processes around Pangnirtung, Nunavut, Canada

Polar Record ◽  
2008 ◽  
Vol 44 (4) ◽  
pp. 335-361 ◽  
Author(s):  
Gita J. Laidler ◽  
Andrew Dialla ◽  
Eric Joamie
Keyword(s):  
Sea Ice ◽  
Regional Scale ◽  
Open Water ◽  
Current Strength ◽  
Ice Formation ◽  
Freeze Thaw ◽  
Ice Conditions ◽  
Cumberland Sound ◽  
Nuanced Understanding ◽  
Ocean Environment

ABSTRACTSea ice has been, and continues to be, an integral component of life in the Inuit community of Pangnirtung, Nunavut. Located in a fiord of the same name off the northeastern end of Cumberland Sound, extensive ice formation occurs within the fiord and the sound. This creates an important travel and hunting platform, and enables access to the coastlines of Cumberland Sound, hunting and fishing grounds, and nearby communities. With the combined importance, dynamism, and continuous use of this frozen ocean environment, local Inuit elders and hunters have developed a detailed and nuanced understanding of sea ice conditions, freeze/thaw processes, and the influences of winds and currents on ice conditions. Working collaboratively with the community of Pangnirtung since September 2003, we present the results of 30 semi-directed interviews, 5 sea ice trips, and 2 focus groups to provide a baseline understanding of local freezing processes (near-shore, open water, sea ice thickening, landfast ice, tidal cracks, and the floe edge), melting processes (snow melt, water accumulation and drainage, and break-up), wind influences on sea ice (wind direction and strength affecting sea ice formation and movement), and, current influences on sea ice (tidal variations and current strength affecting sea ice formation, movement, and polynya size/location). Strong emphasis is placed on Inuktitut terminology and spatial delineations of localised ice conditions and features. Therefore, this paper provides insights into local scale ice conditions and dynamics around Pangnirtung that are not captured in regional scale studies of Cumberland Sound and/or Davis Strait. As the third in a series of three papers on the same subject, but from different communities in the Qikiqtaaluk (Baffin) Region of Nunavut, this paper also provides a comparative summary of Inuktitut and scientific sea ice terminology along with an overview of the broader implications of results for collaborative science, education, and heritage initiatives.

scholarly journals Salt frost attack on concrete: the combined effect of cryogenic suction and chloride binding on ice formation

2021 ◽  
Vol 54 (5) ◽  
Author(s):  
Matthias Müller ◽  
Horst-Michael Ludwig ◽  
Marianne Tange Hasholt
Keyword(s):  
Cement Paste ◽  
Damage Mechanism ◽  
Concrete Surface ◽  
Model Material ◽  
Ice Formation ◽  
Hardened Cement ◽  
Hardened Cement Paste ◽  
Scanning Calorimetry ◽  
Freeze Thaw ◽  
Ice Content

AbstractScaling of concrete due to salt frost attack is an important durability issue in moderate and cold climates. The actual damage mechanism is still not completely understood. Two recent damage theories—the glue spall theory and the cryogenic suction theory—offer plausible, but conflicting explanations for the salt frost scaling mechanism. The present study deals with the cryogenic suction theory, which assumes that freezing concrete can take up unfrozen brine from a partly frozen deicing solution during salt frost attack. According to the model hypothesis, the resulting saturation of the concrete surface layer intensifies the ice formation in this layer and causes salt frost scaling. In this study an experimental technique was developed that makes it possible to quantify to which extent brine uptake can increase ice formation in hardened cement paste (used as a model material for concrete). The experiments were carried out with low temperature differential scanning calorimetry, where specimens were subjected to freeze–thaw cycles while being in contact with NaCl brine. Results showed that the ice content in the specimens increased with subsequent freeze–thaw cycles due to the brine uptake at temperatures below 0 °C. The ability of the hardened cement paste to bind chlorides from the absorbed brine at the same time affected the freezing/melting behavior of the pore solution and the magnitude of the ice content.

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