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Publications (10 of 107) Show all publications
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
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
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
Öhman, J., Gren, P., Lundström, T. & Sjödahl, M. (2022). Interferometric Measurements of Airborne Droplets in the 15-150 μM Range. 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 >>Interferometric Measurements of Airborne Droplets in the 15-150 μM Range
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
Signal Processing
Research subject
Fluid Mechanics; Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-95110 (URN)
Conference
Svenska Mekanikdagarna 2022, Luleå, Sweden, June 15-16, 2022
Available from: 2022-12-30 Created: 2022-12-30 Last updated: 2022-12-30Bibliographically approved
Eriksson, R., Gren, P., Sjödahl, M. & Ramser, K. (2022). Investigation of the Spatial Generation of Stimulated Raman Scattering Using Computer Simulation and Experimentation. Applied Spectroscopy, 26(11), 1307-1316
Open this publication in new window or tab >>Investigation of the Spatial Generation of Stimulated Raman Scattering Using Computer Simulation and Experimentation
2022 (English)In: Applied Spectroscopy, ISSN 0003-7028, E-ISSN 1943-3530, Vol. 26, no 11, p. 1307-1316Article in journal (Refereed) Published
Abstract [en]

Stimulated Raman scattering is a phenomenon with potential use in providing real-time molecular information in three-dimensions (3D) of a sample using imaging. For precise imaging, the knowledge about the spatial generation of stimulated Raman scattering is essential. To investigate the spatial behavior in an idealized case, computer simulations and experiments were performed. For the computer simulations, diffraction theory was used for the beam propagation complemented with nonlinear phase modulation describing the interaction between the light and matter. For the experiments, a volume of ethanol was illuminated by an expanded light beam and a plane inside the volume was imaged in transmission. For generating stimulated Raman scattering, a pump beam was focused into this volume and led to a beam dump after passing the volume. The pulse duration of the two beams were 6 ns and the pump beam energy ranged from 1 to 27 mJ. The effect of increasing pump power on the spatial distribution of the Raman gain and the spatial growth of the signal at different interaction lengths between the beam and the sample was investigated. The spatial width of the region where the stimulated Raman scattering signal was generated for experiments and simulation was 0.21 and 0.09 mm, respectively. The experimental and simulation results showed that most of the stimulated Raman scattering is generated close to the pump beam focus and the maximum peak of the Stokes intensity spatially comes shortly after the peak of the pump intensity.

Place, publisher, year, edition, pages
Sage Publications, 2022
Keywords
Stimulated Raman scattering, simulations, experiments, spatial distribution, spatial rate
National Category
Atom and Molecular Physics and Optics Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-90344 (URN)10.1177/00037028221123593 (DOI)000872145200003 ()36281542 (PubMedID)2-s2.0-85140561101 (Scopus ID)
Funder
Luleå University of TechnologyThe Kempe FoundationsSwedish Foundation for Strategic Research, ITM17-0056
Note

Validerad;2022;Nivå 2;2022-11-03 (sofila)

Available from: 2022-04-21 Created: 2022-04-21 Last updated: 2023-09-05Bibliographically approved
Eriksson, R., Gren, P., Sjödahl, M. & Ramser, K. (2021). 3D Spatial Control of Stimulated Raman Scattering Using a Phase Spatial Light Modulator. In: Proceedings OSA Imaging and Applied Optics Congress 2021 (3D, COSI, DH, ISA, pcAOP): . Paper presented at OSA Imaging and Applied Optics Congress 2021, Washington, DC, United States [Virtual], July 19-23, 2021. Optical Society of America, Article ID 3Th2D.4.
Open this publication in new window or tab >>3D Spatial Control of Stimulated Raman Scattering Using a Phase Spatial Light Modulator
2021 (English)In: Proceedings OSA Imaging and Applied Optics Congress 2021 (3D, COSI, DH, ISA, pcAOP), Optical Society of America, 2021, article id 3Th2D.4Conference paper, Published paper (Refereed)
Abstract [en]

Species specific 3D imaging requires control of where in the sample stimulated Raman gain is achieved. By using a phase spatial light modulator the signal position can be calculated, controlled and directly imaged in 3D.

 

Place, publisher, year, edition, pages
Optical Society of America, 2021
National Category
Atom and Molecular Physics and Optics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-87595 (URN)2-s2.0-85166464442 (Scopus ID)
Conference
OSA Imaging and Applied Optics Congress 2021, Washington, DC, United States [Virtual], July 19-23, 2021
Note

ISBN för värdpublikation: 978-1-943580-89-7

Available from: 2021-10-22 Created: 2021-10-22 Last updated: 2023-09-05Bibliographically approved
Tóth, P., Ögren, Y., Sepman, A., Gren, P. & Wiinikka, H. (2020). Combustion behavior of pulverized sponge iron as a recyclable electrofuel. Powder Technology, 373, 210-219
Open this publication in new window or tab >>Combustion behavior of pulverized sponge iron as a recyclable electrofuel
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2020 (English)In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 373, p. 210-219Article in journal (Refereed) Published
Abstract [en]

In this work, the combustion behavior of pulverized sponge iron (PSI), a practical-grade iron product that was proposed as a potential candidate in the metal fuel cycle, was observed directly using high-magnification shadowgraphy and other optical diagnostics techniques. The PSI was combusted in a laboratory-scale, McKenna flat-flame burner. Results suggest that, in agreement with theoretical models, PSI combusted heterogeneously, with most of the particle mass converting to an intact, solid oxide. However, in contrast with previous hypotheses, the formation of a microflame of combusting aerosol that was attached to the particle surface was observed. Results from quantitative shadowgraphy indicated near-instantaneous melting and complex behavior—we attempted to explain these based on the FeO phase diagram. The analysis of micron- and nano-sized combustion products confirmed that the PSI combusted heterogeneously and a gaseous sub-oxide was formed. Combustion under high excess oxygen was hypothesized to reduce the formation of these oxides.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Metal fuels, Metal combustion, Iron combustion, Energy carrier, Energy vector, Zero‑carbon
National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-79629 (URN)10.1016/j.powtec.2020.05.078 (DOI)000558909200020 ()2-s2.0-85087108013 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-07-07 (alebob)

Available from: 2020-06-16 Created: 2020-06-16 Last updated: 2020-08-31Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-8355-2414

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