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Bahaloo, H., Gren, P., Casselgren, J., Forsberg, F. & Sjödahl, M. (2024). Capillary Bridge in Contact with Ice Particles Can Be Related to the Thin Liquid Film on Ice. Journal of cold regions engineering, 38(1), Article ID 04023021.
Open this publication in new window or tab >>Capillary Bridge in Contact with Ice Particles Can Be Related to the Thin Liquid Film on Ice
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2024 (English)In: Journal of cold regions engineering, ISSN 0887-381X, E-ISSN 1943-5495, Vol. 38, no 1, article id 04023021Article in journal (Refereed) Published
Abstract [en]

We experimentally demonstrate the presence of a capillary bridge in the contact between an ice particle and a smooth aluminum surface at a relative humidity of approximately 50% and temperatures below the melting point. We conduct the experiments in a freezer with a controlled temperature and consider the mechanical instability of the bridge upon separation of the ice particle from the aluminum surface at a constant speed. We observe that a liquid bridge forms, and this formation becomes more pronounced as the temperature approaches the melting point. We also show that the separation distance is proportional to the cube root of the volume of the bridge. We hypothesize that the volume of the liquid bridge can be used to provide a rough estimate of the thickness of the liquid layer on the ice particle since in the absence of other driving mechanisms, some of the liquid on the surface must have been pulled to the bridge area. We show that the estimated value lies within the range previously reported in the literature. With these assumptions, the estimated thickness of the liquid layer decreases from nearly 56 nm at T = −1.7°C to 0.2 nm at T = −12.7°C. The dependence can be approximated with a power law, proportional to (TM − T)−β, where β < 2.6 and TM is the melting temperature. We further observe that for a rough surface, the capillary bridge formation in the considered experimental conditions vanishes.

Place, publisher, year, edition, pages
American Society of Civil Engineers (ASCE), 2024
National Category
Infrastructure Engineering
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-102441 (URN)10.1061/JCRGEI.CRENG-738 (DOI)2-s2.0-85175442634 (Scopus ID)
Note

Validerad;2023;Nivå 2;2023-11-15 (sofila);

Full text license: CC BY

Available from: 2023-11-13 Created: 2023-11-13 Last updated: 2023-11-15Bibliographically approved
Bahaloo, H., Forsberg, F., Casselgren, J., Lycksam, H. & Sjödahl, M. (2024). Mapping of density-dependent material properties of dry manufactured snow using μCT. Applied Physics A: Materials Science & Processing, 130, Article ID 16.
Open this publication in new window or tab >>Mapping of density-dependent material properties of dry manufactured snow using μCT
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2024 (English)In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 130, article id 16Article in journal (Refereed) Published
Abstract [en]

Despite the significance of snow in various cryospheric, polar, and construction contexts, more comprehensive studies are required on its mechanical properties. In recent years, the utilization of μ CT has yielded valuable insights into snow analysis. Our objective is to establish a methodology for mapping density-dependent material properties for dry manufactured snow within the density range of 400–600 kg/m 3 utilizing μ CT imaging and step-wise, quasi-static, mechanical loading. We also aim to investigate the variations in the structural parameters of snow during loading. The three-dimensional (3D) structure of snow is captured using μ CT with 801 projections at the beginning of the experiments and at the end of each loading step. The sample is compressed at a temperature of − 18 o C using a constant rate of deformation (0.2 mm/min) in multiple steps. The relative density of the snow is determined at each load step using binary image segmentation. It varies from 0.44 in the beginning to nearly 0.65 at the end of the loading, which corresponds to a density range of 400–600 kg/m 3 . The estimated modulus and viscosity terms, obtained from the Burger’s model, show an increasing trend with density. The values of the Maxwell and Kelvin–Voigt moduli were found to range from 60 to 320 MPa and from 6 to 40 MPa, respectively. Meanwhile, the viscosity values for the Maxwell and Kelvin–Voigt models varied from 0.4 to 3.5 GPa-s, and 0.3–3.2 GPa-s, respectively, within the considered density range. In addition, Digital Volume Correlation (DVC) was used to calculate the full-field strain distribution in the specimen at each load step. The image analysis results show that, the particle size and specific surface area (SSA) do not change significantly within the studied range of loading and densities, while the sphericity of the particles is increased. The grain diameter ranges from approximately 100 μ m to nearly 400 μ m, with a mode of nearly 200 μ m. The methodology presented in this study opens up a path for an extensive statistical analysis of the material properties by experimenting more snow samples.

Place, publisher, year, edition, pages
Springer Science and Business Media Deutschland GmbH, 2024
Keywords
Digital volume correlation, Image analysis, Material modeling, Micro tomography, Snow, Stress-strain response
National Category
Other Materials Engineering
Research subject
Experimental Mechanics; Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-103511 (URN)10.1007/s00339-023-07167-y (DOI)2-s2.0-85179360802 (Scopus ID)
Note

Full text license: CC BY

Available from: 2024-01-08 Created: 2024-01-08 Last updated: 2024-01-08
Bahaloohoreh, H., Forsberg, F., Lycksam, H., Casselgren, J. & Sjödahl, M. (2024). Material mapping strategy to identify the density-dependent properties of dry natural snow. Applied Physics A: Materials Science & Processing, 130(2), Article ID 141.
Open this publication in new window or tab >>Material mapping strategy to identify the density-dependent properties of dry natural snow
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2024 (English)In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 130, no 2, article id 141Article in journal (Refereed) Published
Abstract [en]

The mechanical properties of natural snow play a crucial role in understanding glaciers, avalanches, polar regions, and snow-related constructions. Research has concentrated on how the mechanical properties of snow vary, primarily with its density; the integration of cutting-edge techniques like micro-tomography with traditional loading methods can enhance our comprehension of these properties in natural snow. This study employs CT imaging and uniaxial compression tests, along with the Digital Volume Correlation (DVC) to investigate the density-dependent material properties of natural snow. The data from two snow samples, one initially non-compressed (test 1) and the other initially compressed (test 2), were fed into Burger’s viscoelastic model to estimate the material properties. CT imaging with 801 projections captures the three-dimensional structure of the snow initially and after each loading step at -18C, using a constant deformation rate (0.2 mm/min). The relative density of the snow, ranging from 0.175 to 0.39 (equivalent to 160–360 kg/m), is determined at each load step through binary image segmentation. Modulus and viscosity terms, estimated from Burger’s model, exhibit a density-dependent increase. Maxwell and Kelvin–Voigt moduli range from 0.5 to 14 MPa and 0.1 to 0.8 MPa, respectively. Viscosity values for the Maxwell and Kelvin–Voigt models vary from 0.2 to 2.9 GPa-s and 0.2 to 2.3 GPa-s within the considered density range, showing an exponent between 3 and 4 when represented as power functions. Initial grain characteristics for tests 1 and 2, obtained through image segmentation, reveal an average Specific Surface Area (SSA) of around 55 1/mm and 40 1/mm, respectively. The full-field strain distribution in the specimen at each load step is calculated using the DVC, highlighting strong strain localization indicative of non-homogeneous behavior in natural snow. These findings not only contribute to our understanding of natural snow mechanics but also hold implications for applications in fields such as glacier dynamics and avalanche prediction.

Place, publisher, year, edition, pages
Springer Nature, 2024
Keywords
Material mapping, Micro tomography, Compression test, Digital volume correlation, Snow and ice
National Category
Other Materials Engineering
Research subject
Experimental Mechanics; Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-104236 (URN)10.1007/s00339-024-07288-y (DOI)2-s2.0-85183678465 (Scopus ID)
Note

Validerad;2024;Nivå 2;2024-02-12 (joosat);

CC BY Full text license

Available from: 2024-02-12 Created: 2024-02-12 Last updated: 2024-02-12Bibliographically approved
Bahaloohoreh, H., Gren, P., Casselgren, J., Forsberg, F. & Sjödahl, M. (2023). Capillary bridge in contact of ice particles reveals the thin liquid film on ice.
Open this publication in new window or tab >>Capillary bridge in contact of ice particles reveals the thin liquid film on ice
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2023 (English)Manuscript (preprint) (Other academic)
National Category
Other Engineering and Technologies not elsewhere specified
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-94783 (URN)
Available from: 2022-12-08 Created: 2022-12-08 Last updated: 2022-12-09
Eriksson, R., Gren, P., Sjödahl, M. & Ramser, K. (2022). 3D spatial control and the spatial generation of stimulated Raman scattering in ethanol. In: : . Paper presented at ECONOS European Conference on Non-linear Optical Spectroscopy, September 25-28, 2022, Kiruna, Sweden.
Open this publication in new window or tab >>3D spatial control and the spatial generation of stimulated Raman scattering in ethanol
2022 (English)Conference paper, Oral presentation only (Other academic)
Keywords
Stimulated Raman scattering
National Category
Atom and Molecular Physics and Optics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-97135 (URN)
Conference
ECONOS European Conference on Non-linear Optical Spectroscopy, September 25-28, 2022, Kiruna, Sweden
Available from: 2023-05-12 Created: 2023-05-12 Last updated: 2023-09-05Bibliographically approved
Dembele, V., Wahl, J., Sjödahl, M. & Ramser, K. (2022). Correlation properties of a spatially quasi-incoherent imaging interferometer. Applied Optics, 61(19), 5806-5812
Open this publication in new window or tab >>Correlation properties of a spatially quasi-incoherent imaging interferometer
2022 (English)In: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 61, no 19, p. 5806-5812Article in journal (Refereed) Published
Abstract [en]

The depth-gating capacity of a spatially quasi-incoherent imaging interferometer is investigated in relation to the 3D correlation properties of diffraction field laser speckles. The system exploits a phase-stepped imaging Michelson-type interferometer in which spatially quasi-incoherent illumination is generated by passing an unexpanded laser beam through a rotating diffuser. Numerical simulations and optical experiments both verify that the depth-gating capacity of the imaging interferometer scales as 𝜆/2NA2𝑝λ/2NAp2, where 𝜆λ is the wavelength of the laser and NA𝑝NAp is the numerical aperture of the illumination. For a set depth gate of 150 µm, the depth-gating capacity of the interferometer is demonstrated by scanning a standard USAF target through the measurement volume. The results obtained show that an imaging tool of this kind is expected to provide useful capabilities for imaging through disturbing media and where a single wavelength is required.

Place, publisher, year, edition, pages
Optical Society of America, 2022
National Category
Atom and Molecular Physics and Optics Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-92225 (URN)10.1364/AO.459241 (DOI)000822017300038 ()36255816 (PubMedID)2-s2.0-85133659511 (Scopus ID)
Note

Validerad;2022;Nivå 2;2022-07-22 (sofila)

Available from: 2022-07-22 Created: 2022-07-22 Last updated: 2023-10-11Bibliographically approved
Dembele, V., Wahl, J., Sjödahl, M. & Ramser, K. (2022). Depth-resolved interferometric imaging utilizing a spatially quasi-incoherent light source. In: Proceedings Digital Holography and 3-D Imaging 2022: . Paper presented at Digital Holography and Three-Dimensional Imaging Topical Meeting, Cambridge, United Kingdom, August 1-4, 2022. Optica Publishing Group, Article ID W7A.1.
Open this publication in new window or tab >>Depth-resolved interferometric imaging utilizing a spatially quasi-incoherent light source
2022 (English)In: Proceedings Digital Holography and 3-D Imaging 2022, Optica Publishing Group , 2022, article id W7A.1Conference paper, Published paper (Refereed)
Abstract [en]

An interferometric technique that utilize a spatially quasi-incoherent light source to perform interferometric measurements involving diffusely scattering objects is presented. The proposed technique is demonstrated with settings that give a depth gate of 90 µm.

Place, publisher, year, edition, pages
Optica Publishing Group, 2022
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-94793 (URN)2-s2.0-85141463701 (Scopus ID)
Conference
Digital Holography and Three-Dimensional Imaging Topical Meeting, Cambridge, United Kingdom, August 1-4, 2022
Funder
The Kempe Foundations
Note

ISBN for host publication: 978-1-957171-12-8

Available from: 2022-12-12 Created: 2022-12-12 Last updated: 2023-09-05Bibliographically approved
Öhman, J., Gren, P., Sjödahl, M. & Lundström, S. (2022). Experimental investigation of face mask filtration in the 15–150 μm range for stationary flows. Journal of Applied Physics, 131(4), Article ID 044702.
Open this publication in new window or tab >>Experimental investigation of face mask filtration in the 15–150 μm range for stationary flows
2022 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 131, no 4, article id 044702Article in journal (Refereed) Published
Abstract [en]

The effectiveness of face masks for preventing airborne transmission has been debated heavily during the COVID-19 pandemic. This paper investigates the filtration efficiency for four different face mask materials, two professional and two homemade, for different airflow conditions using model experiments and artificially generated water droplets. The size range chosen represents particles with the largest volume that can be suspended in air. The particles are detected using double pulsed interferometric particle imaging, from which it is possible to estimate the positions, velocity, and size of individual particles. It is found that all the tested face masks are efficient in preventing particles from transmission through the mask material. In the presence of leakage, particles larger than approximately 100𝜇m are completely removed from the air stream. The filtration efficiency decreases with the decreasing particle size to approximately 80% for 15𝜇m particles. The size dependency in the leakage is mainly due to the momentum of the larger particles. The results show that even simple face mask materials with leakage prevent a large portion of the emitted particles in the 15–150 𝜇m range.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2022
National Category
Production Engineering, Human Work Science and Ergonomics
Research subject
Experimental Mechanics; Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-89473 (URN)10.1063/5.0077710 (DOI)000802533000005 ()2-s2.0-85123754250 (Scopus ID)
Funder
Swedish Research Council, 2020-05871
Note

Validerad;2022;Nivå 2;2022-03-14 (johcin)

Available from: 2022-03-14 Created: 2022-03-14 Last updated: 2022-07-06Bibliographically approved
Bahaloohoreh, H., Eidevåg, T., Gren, P., Casselgren, J., Forsberg, F., Abrahamsson, P. & Sjödahl, M. (2022). Ice sintering: Dependence of sintering force on temperature, load, duration, and particle size. Journal of Applied Physics, 131(2), Article ID 025109.
Open this publication in new window or tab >>Ice sintering: Dependence of sintering force on temperature, load, duration, and particle size
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2022 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 131, no 2, article id 025109Article in journal (Refereed) Published
Abstract [en]

We present experiments along with an approximate, semi-analytic, close-form solution to predict ice sintering force as a function of temperature, contact load, contact duration, and particle size during the primary stage of sintering. The ice sintering force increases nearly linear with increasing contact load but nonlinear with both contact duration and particle size in the form of a power law. The exponent of the power law for size dependence is around the value predicted by general sintering theory. The temperature dependence of the sintering force is also nonlinear and follows the Arrhenius equation. At temperatures closer to the melting point, a liquid bridge is observed upon the separation of the contacted ice particles. We also find that the ratio of ultimate tensile strength of ice to the axial stress concentration factor in tension is an important factor in determining the sintering force, and a value of nearly 1.1 MPa can best catch the sintering force of ice in different conditions. We find that the activation energy is around 41.4KJ/mol41.4KJ/mol, which is close to the previously reported data. Also, our results suggest that smaller particles are “stickier” than larger particles. Moreover, during the formation of the ice particles, cavitation and surface cracking is observed which can be one of the sources for the variations observed in the measured ice sintering force.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2022
National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-88792 (URN)10.1063/5.0073824 (DOI)000746515900007 ()2-s2.0-85123639304 (Scopus ID)
Note

Validerad;2022;Nivå 2;2022-01-17 (johcin)

Available from: 2022-01-17 Created: 2022-01-17 Last updated: 2022-12-09Bibliographically approved
Bahaloo, H., Eidevåg, T., Gren, P., Casselgren, J., Forsberg, F., Abrahamsson, P. & Sjödahl, M. (2022). Ice Sintering: Dependence of Sintering Force on Temperature, Load, Duration, and Particle Size. In: Pär Jonsén; Lars-Göran Westerberg; Simon Larsson; Erik Olsson (Ed.), Svenska Mekanikdagar 2022: . Paper presented at Svenska Mekanikdagarna 2022, Luleå, Sweden, June 15-16, 2022 . Luleå tekniska universitet
Open this publication in new window or tab >>Ice Sintering: Dependence of Sintering Force on Temperature, Load, Duration, and Particle Size
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2022 (English)In: Svenska Mekanikdagar 2022 / [ed] Pär Jonsén; Lars-Göran Westerberg; Simon Larsson; Erik Olsson, Luleå tekniska universitet, 2022Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Luleå tekniska universitet, 2022
National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-95068 (URN)
Conference
Svenska Mekanikdagarna 2022, Luleå, Sweden, June 15-16, 2022 
Note

Presentation of an earlier published article with DOI: 10.1063/5.0073824

Available from: 2022-12-29 Created: 2022-12-29 Last updated: 2024-02-12Bibliographically approved
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