Calibration and validation represent crucial but often-overlooked ingredients in the successful application of discrete element method (DEM) simulations. Without rigorous calibration/validation protocols, the results of DEM simulations can be imprecise or even unphysical, yet all too often the methods used by practitioners are at best cursory, and at worst entirely absent. As the particle-handling industries show an increasing interest in DEM, it is vital that this issue be resolved lest a potentially powerful tool be written off by industry as unreliable. In this work, we provide a concise overview of contemporary methods used in the calibration and validation of DEM simulations of powder flows, providing practical insights into their strengths and weaknesses, and ideas for manners in which they may be improved and/or rendered more easily adoptable in the future.
{"title":"Calibration of DEM simulations for dynamic particulate systems","authors":"C. Windows-Yule, A. Neveu","doi":"10.4279/pip.140010","DOIUrl":"https://doi.org/10.4279/pip.140010","url":null,"abstract":"Calibration and validation represent crucial but often-overlooked ingredients in the successful application of discrete element method (DEM) simulations. Without rigorous calibration/validation protocols, the results of DEM simulations can be imprecise or even unphysical, yet all too often the methods used by practitioners are at best cursory, and at worst entirely absent. As the particle-handling industries show an increasing interest in DEM, it is vital that this issue be resolved lest a potentially powerful tool be written off by industry as unreliable. In this work, we provide a concise overview of contemporary methods used in the calibration and validation of DEM simulations of powder flows, providing practical insights into their strengths and weaknesses, and ideas for manners in which they may be improved and/or rendered more easily adoptable in the future.","PeriodicalId":19791,"journal":{"name":"Papers in Physics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47293040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Among granular matter, one type of particle has special properties. Upon being assembled in disordered configurations, these particles interlock, hook, almost braid, and – surprisingly, considering their relatively low packing fractions – show exceptional shear strength.Such is the case of non-convex particles. They have been used in the shapes of tetrapods, ‘L’, ‘Z’, stars, and many others, to protect coasts or build self-standing structures requiring no binders or external supports. Although these structures are often designed without a comprehensive mechanical characterization, they have already demonstrated great potential as highly resistant construction materials. Nevertheless, it is natural to attempt to find the most appropriate non-convex shapes for any given application. Can a particle shape be tuned to obtain a desired mechanical behavior? Although this question cannot be answered yet, current technological, simulation, and experimental developments strongly suggest that it can be resolved in the next decade. A clear understanding of the relationships between particle shapes, mechanical response, and packing properties will be key to providing insights into the behavior of these materials. Such work should stand on 1) robust and general shape descriptors that encode the complexity of non-convex shapes (i.e., the number of arms, the symmetries, and asymmetries of the bodies, the presence of holes, etc.), 2) the analysis of the response of assemblies under different loading conditions, and 3) the disposition and reliability of non-convex shapes to ensure durability. The manufacturing process and an efficient use of resources are additional elements that could further help to optimize particle shape. In the quest of designing bespoke non-convex particles, this paper consolidates the challenges that remain unresolved. It also outlines some routes to explore based on the latest developments in technology and research.
{"title":"Bespoke particle shapes in granular matter","authors":"D. Cantor, Manuel Cárdenas-Barrantes, L. Orozco","doi":"10.4279/pip.140007","DOIUrl":"https://doi.org/10.4279/pip.140007","url":null,"abstract":"Among granular matter, one type of particle has special properties. Upon being assembled in disordered configurations, these particles interlock, hook, almost braid, and – surprisingly, considering their relatively low packing fractions – show exceptional shear strength.Such is the case of non-convex particles. They have been used in the shapes of tetrapods, ‘L’, ‘Z’, stars, and many others, to protect coasts or build self-standing structures requiring no binders or external supports. Although these structures are often designed without a comprehensive mechanical characterization, they have already demonstrated great potential as highly resistant construction materials. Nevertheless, it is natural to attempt to find the most appropriate non-convex shapes for any given application. Can a particle shape be tuned to obtain a desired mechanical behavior? Although this question cannot be answered yet, current technological, simulation, and experimental developments strongly suggest that it can be resolved in the next decade. A clear understanding of the relationships between particle shapes, mechanical response, and packing properties will be key to providing insights into the behavior of these materials. Such work should stand on 1) robust and general shape descriptors that encode the complexity of non-convex shapes (i.e., the number of arms, the symmetries, and asymmetries of the bodies, the presence of holes, etc.), 2) the analysis of the response of assemblies under different loading conditions, and 3) the disposition and reliability of non-convex shapes to ensure durability. The manufacturing process and an efficient use of resources are additional elements that could further help to optimize particle shape. In the quest of designing bespoke non-convex particles, this paper consolidates the challenges that remain unresolved. It also outlines some routes to explore based on the latest developments in technology and research.","PeriodicalId":19791,"journal":{"name":"Papers in Physics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41428644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Barés, Manuel Cárdenas-Barrantes, D. Cantor, M. Renouf, É. Azéma
Softer than soft, squishy granular matter is composed of grains capable of significantly changing their shape (typically a deformation larger than 10%) without tearing or breaking. Because of the difficulty to test these materials experimentally and numerically, such a family of discrete systems remains largely ignored in the granular matter physics field despite being commonly found in nature and industry. Either from a numerical, experimental, or analytical point of view, the study of highly deformable granular matter involves several challenges covering, for instance: (i) the need to include a large diversity of grain rheology, (ii) the need to consider large material deformations, and (iii) analysis of the effects of large body distortion on the global scale. In this article, we propose a thorough definition of these squishy granular systems and we summarize the upcoming challenges in their study.
{"title":"Softer than soft: Diving into squishy granular matter","authors":"J. Barés, Manuel Cárdenas-Barrantes, D. Cantor, M. Renouf, É. Azéma","doi":"10.4279/pip.140009","DOIUrl":"https://doi.org/10.4279/pip.140009","url":null,"abstract":"Softer than soft, squishy granular matter is composed of grains capable of significantly changing their shape (typically a deformation larger than 10%) without tearing or breaking. Because of the difficulty to test these materials experimentally and numerically, such a family of discrete systems remains largely ignored in the granular matter physics field despite being commonly found in nature and industry. Either from a numerical, experimental, or analytical point of view, the study of highly deformable granular matter involves several challenges covering, for instance: (i) the need to include a large diversity of grain rheology, (ii) the need to consider large material deformations, and (iii) analysis of the effects of large body distortion on the global scale. In this article, we propose a thorough definition of these squishy granular systems and we summarize the upcoming challenges in their study.","PeriodicalId":19791,"journal":{"name":"Papers in Physics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41601042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Schroter, Chenghao Lyu, Jiayun Huang, Kai Huang
In this perspective article, we discuss the challenges of imaging assemblies of particles in three dimensions. Starting from a brief motivation for the investigation of particulate materials, we provide an overview of experimental approaches developed for imaging particles. We list the challenges and existing solutions associated with X-ray tomography, one of the standard methods to study statics. Subsequently, we discuss challenges and opportunities arising from emerging new techniques such as radar tracking and ‘smart’ tracers for exploring granular dynamics. We close with a tentative view on the outstanding problems and potential solutions in the future.
{"title":"Challenges of 'imaging' particulate materials in three dimensions","authors":"M. Schroter, Chenghao Lyu, Jiayun Huang, Kai Huang","doi":"10.4279/pip.140015","DOIUrl":"https://doi.org/10.4279/pip.140015","url":null,"abstract":"In this perspective article, we discuss the challenges of imaging assemblies of particles in three dimensions. Starting from a brief motivation for the investigation of particulate materials, we provide an overview of experimental approaches developed for imaging particles. We list the challenges and existing solutions associated with X-ray tomography, one of the standard methods to study statics. Subsequently, we discuss challenges and opportunities arising from emerging new techniques such as radar tracking and ‘smart’ tracers for exploring granular dynamics. We close with a tentative view on the outstanding problems and potential solutions in the future.","PeriodicalId":19791,"journal":{"name":"Papers in Physics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49450409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thermophysical properties of compound forming binary liquid mercury-lead alloy at temperature 600 K have been reported as a function of concentration by considering HgPb2 complex using different modelling equations. The thermodynamic properties such as the Gibbs free energy, enthalpy of mixing, chemical activity of each component, and microscopic properties such as concentration fluctuation in long-wavelength limit and Warren-Cowley short range order parameter of the alloy are studied by quasi-chemical approximation. This research paper places additional emphasis on the interaction energy parameters between the atoms of the alloy. The theoretical and experimental data are compared to determine the model’s validity. Compound formation model, statistical mechanical technique, and improved derivation of the Butler equation have all been used to investigate surface tension. The alloy’s viscosity is investigated using the Kozlov-Ronanov-Petrov equation, the Kaptay equation, and the Budai-Benko-Kaptay model. The study depicts a weak interaction of the alloy, and the theoretical thermodynamic data derived at 600 K are in good agreement with the experimental results. The surface tension is slightly different in the compound formation model than in the statistical mechanical approach and the Butler equation at greater bulk concentrations of lead. The estimated viscosities in each of the three models are substantially identical.
{"title":"Thermophysical behavior of mercury-lead liquid alloy","authors":"N. Panthi, I. Bhandari, I. Koirala","doi":"10.4279/pip.140005","DOIUrl":"https://doi.org/10.4279/pip.140005","url":null,"abstract":"Thermophysical properties of compound forming binary liquid mercury-lead alloy at temperature 600 K have been reported as a function of concentration by considering HgPb2 complex using different modelling equations. The thermodynamic properties such as the Gibbs free energy, enthalpy of mixing, chemical activity of each component, and microscopic properties such as concentration fluctuation in long-wavelength limit and Warren-Cowley short range order parameter of the alloy are studied by quasi-chemical approximation. This research paper places additional emphasis on the interaction energy parameters between the atoms of the alloy. The theoretical and experimental data are compared to determine the model’s validity. Compound formation model, statistical mechanical technique, and improved derivation of the Butler equation have all been used to investigate surface tension. The alloy’s viscosity is investigated using the Kozlov-Ronanov-Petrov equation, the Kaptay equation, and the Budai-Benko-Kaptay model. The study depicts a weak interaction of the alloy, and the theoretical thermodynamic data derived at 600 K are in good agreement with the experimental results. The surface tension is slightly different in the compound formation model than in the statistical mechanical approach and the Butler equation at greater bulk concentrations of lead. The estimated viscosities in each of the three models are substantially identical.","PeriodicalId":19791,"journal":{"name":"Papers in Physics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71011083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Prijil Mathew, Sajith T Mathews, Paul Issac, P. Kurian
Through experiments and theoretical analysis, we investigated the similarity of gas discharge in low-pressure Argon gaps between two plane-parallel electrodes. We found that the breakdown voltages depended not only on gap length and the product of gas pressureand gap length but also on the aspect ratio of the gap, i.e. Ub = f (pd, d/r). When we considered similar discharge gaps, the radius r, gap length d, and gas pressure p fulfilled the conditions of p1 r1 = p2 r2 and p1d1 = p2 d2. In this situation, the reduced field E/p was also constant. The voltage-current characteristic curves of similar gaps were approximately the same, which is a novel experimental result. Comparison of the discharge physical parameters of the scaled-down gap and prototype gap shows that the proportional relations can be derived from the similarity law. Our experimental results provide some instructions on extrapolating two similar gaps and their discharge properties. Application of the similarity law is straightforward when we scale the discharges up or down if they are too small or large.
{"title":"Experimental study on the similarity of gas discharge in low-pressure Argon gaps","authors":"Prijil Mathew, Sajith T Mathews, Paul Issac, P. Kurian","doi":"10.4279/pip.140004","DOIUrl":"https://doi.org/10.4279/pip.140004","url":null,"abstract":"Through experiments and theoretical analysis, we investigated the similarity of gas discharge in low-pressure Argon gaps between two plane-parallel electrodes. We found that the breakdown voltages depended not only on gap length and the product of gas pressureand gap length but also on the aspect ratio of the gap, i.e. Ub = f (pd, d/r). When we considered similar discharge gaps, the radius r, gap length d, and gas pressure p fulfilled the conditions of p1 r1 = p2 r2 and p1d1 = p2 d2. In this situation, the reduced field E/p was also constant. The voltage-current characteristic curves of similar gaps were approximately the same, which is a novel experimental result. Comparison of the discharge physical parameters of the scaled-down gap and prototype gap shows that the proportional relations can be derived from the similarity law. Our experimental results provide some instructions on extrapolating two similar gaps and their discharge properties. Application of the similarity law is straightforward when we scale the discharges up or down if they are too small or large.","PeriodicalId":19791,"journal":{"name":"Papers in Physics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44264364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Granular materials are found throughout nature and industry: in landslides, avalanches, and river beds, and also in pharmaceutics, food, and mineral processing. Many behaviors of these materials, including the ways in which they pack, deform, flow, and transmit energy, can be fully understood only in the context of inter-particle forces. However, we lack techniques for measuring 3D inter-particle force evolution at subsecond timescales due to technological limitations. Measurements of 3D force chain evolution at subsecond timescales would help validate and extend theories and models that explicitly or implicitly consider force chain dynamics in their predictions. Here, we discuss open challenges associated with force chain evolution on these timescales, challenges limiting such measurements, and possible routes for overcoming these challenges in the coming decade.
{"title":"Challenges and opportunities in measuring time-resolved force chain evolution in 3D granular materials","authors":"R. Hurley, C. Zhai","doi":"10.4279/pip.140003","DOIUrl":"https://doi.org/10.4279/pip.140003","url":null,"abstract":"Granular materials are found throughout nature and industry: in landslides, avalanches, and river beds, and also in pharmaceutics, food, and mineral processing. Many behaviors of these materials, including the ways in which they pack, deform, flow, and transmit energy, can be fully understood only in the context of inter-particle forces. However, we lack techniques for measuring 3D inter-particle force evolution at subsecond timescales due to technological limitations. Measurements of 3D force chain evolution at subsecond timescales would help validate and extend theories and models that explicitly or implicitly consider force chain dynamics in their predictions. Here, we discuss open challenges associated with force chain evolution on these timescales, challenges limiting such measurements, and possible routes for overcoming these challenges in the coming decade.","PeriodicalId":19791,"journal":{"name":"Papers in Physics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44161684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cerium oxide $text{CeO}_2$, or ceria, has gained increasing interest owing to its excellent catalytic applications. Under the framework of density functional theory (DFT), this contribution demonstrates the effect that introducing the element nickel (Ni) into the ceria lattice has on its electronic, structural, and optical characteristics. Electronic density of states (DOSs) analysis shows that Ni integration leads to a shrinkage of Ce 4$f$ states and improvement of Ni 3$d$ states in the bottom of the conduction band. Furthermore, the calculated optical absorption spectra of an Ni-doped $text{CeO}_2$ system shifts towards longer visible light and infrared regions. Results indicate that Ni-doping a $text{CeO}_2$ system would result in a decrease of the band gap. Finally, Mulliken's charge transfer of the $text{Ce}_{1-x}text{Ni}_xtext{O}_2$ system exhibits an ionic bond between Ce or Ni and O, and covalent bonds between Ce and Ni atoms. The analysis of absorption spectra demonstrates that Ni-doped $text{CeO}_2$ is a material with potential use in photocatalytic, photovoltaic, and solar panels.
{"title":"Electronic and optical properties of nickel-doped ceria: A computational modelling study","authors":"H. Miran, Zainab N. Jaf","doi":"10.4279/pip.140002","DOIUrl":"https://doi.org/10.4279/pip.140002","url":null,"abstract":"Cerium oxide $text{CeO}_2$, or ceria, has gained increasing interest owing to its excellent catalytic applications. Under the framework of density functional theory (DFT), this contribution demonstrates the effect that introducing the element nickel (Ni) into the ceria lattice has on its electronic, structural, and optical characteristics. Electronic density of states (DOSs) analysis shows that Ni integration leads to a shrinkage of Ce 4$f$ states and improvement of Ni 3$d$ states in the bottom of the conduction band. Furthermore, the calculated optical absorption spectra of an Ni-doped $text{CeO}_2$ system shifts towards longer visible light and infrared regions. Results indicate that Ni-doping a $text{CeO}_2$ system would result in a decrease of the band gap. Finally, Mulliken's charge transfer of the $text{Ce}_{1-x}text{Ni}_xtext{O}_2$ system exhibits an ionic bond between Ce or Ni and O, and covalent bonds between Ce and Ni atoms. The analysis of absorption spectra demonstrates that Ni-doped $text{CeO}_2$ is a material with potential use in photocatalytic, photovoltaic, and solar panels.","PeriodicalId":19791,"journal":{"name":"Papers in Physics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49641262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Parisi, Germán A. Patterson, Lucio Pagni, Agustina Osimani, Tomas Bacigalupo, Juan Godfrid, Federico M. Bergagna, Manuel Rodriguez Brizi, Pedro Momesso, Fermin L. Gomez, Jimena Lozano, Juan Baader, Ignacio Ribas, Facundo P. Astiz Meyer, Miguel Di Luca, Nicol'as E. Barrera, Ezequiel M. Keimel Álvarez, Maite M. Herran Oyhanarte, Pedro R. Pingarilho, Ximena Zuberbuhler, Felipe Gorostiaga
In the present work we study how the number of simulated customers (occupancy) affects social distance in an ideal supermarket, considering realistic typical dimensions and processing times (product selection and checkout). From the simulated trajectories we measure social distance events of less than 2 m, and their duration. Among other observables, we define a physical distance coefficient that informs how many events (of a given duration) each agent experiences.
{"title":"Physical distance characterization using pedestrian dynamics simulation","authors":"D. Parisi, Germán A. Patterson, Lucio Pagni, Agustina Osimani, Tomas Bacigalupo, Juan Godfrid, Federico M. Bergagna, Manuel Rodriguez Brizi, Pedro Momesso, Fermin L. Gomez, Jimena Lozano, Juan Baader, Ignacio Ribas, Facundo P. Astiz Meyer, Miguel Di Luca, Nicol'as E. Barrera, Ezequiel M. Keimel Álvarez, Maite M. Herran Oyhanarte, Pedro R. Pingarilho, Ximena Zuberbuhler, Felipe Gorostiaga","doi":"10.4279/pip.140001","DOIUrl":"https://doi.org/10.4279/pip.140001","url":null,"abstract":"In the present work we study how the number of simulated customers (occupancy) affects social distance in an ideal supermarket, considering realistic typical dimensions and processing times (product selection and checkout). From the simulated trajectories we measure social distance events of less than 2 m, and their duration. Among other observables, we define a physical distance coefficient that informs how many events (of a given duration) each agent experiences.","PeriodicalId":19791,"journal":{"name":"Papers in Physics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44765520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Frosted glass is a common, low cost material. Its roughness can be used to control how it is wet by water. In this paper, the wetting properties of silicone oil and water are investigated. For the oil, wetting is total since the oleophilic character of the glass is enhanced by its roughness. Due to the remarkable optical properties of frosted glass, the spreading of oil droplets on its surface was recorded over three months. Frosted glass is a parahydrophilic surface because of its large contact angle hysteresis (up to 80° ). The behaviour of oil and water droplets was compared on a long piece of inclined frosted glass. The trajectories (and the spreading) of the droplets were studied and phenomenological laws were deduced to describe the dependence of the droplet speed on the initial volume of the droplet and the angle of inclination. Such dependences of speed at long travel distances (100 times the capillary length) were deduced and rationalised with a simple model that takes into account the thickness of the wake. Moreover, we analysed the flow inside the wake of water droplets sliding on inclined frosted glass. Suggestions are given on how to exploit drainage of the water droplet wake and the high hysteresis of water within the framework of open microfluidics.
{"title":"The wetting properties of frosted glass","authors":"S. Dorbolo","doi":"10.4279/pip.130006","DOIUrl":"https://doi.org/10.4279/pip.130006","url":null,"abstract":"Frosted glass is a common, low cost material. Its roughness can be used to control how it is wet by water. In this paper, the wetting properties of silicone oil and water are investigated. For the oil, wetting is total since the oleophilic character of the glass is enhanced by its roughness. Due to the remarkable optical properties of frosted glass, the spreading of oil droplets on its surface was recorded over three months. Frosted glass is a parahydrophilic surface because of its large contact angle hysteresis (up to 80° ). The behaviour of oil and water droplets was compared on a long piece of inclined frosted glass. The trajectories (and the spreading) of the droplets were studied and phenomenological laws were deduced to describe the dependence of the droplet speed on the initial volume of the droplet and the angle of inclination. Such dependences of speed at long travel distances (100 times the capillary length) were deduced and rationalised with a simple model that takes into account the thickness of the wake. Moreover, we analysed the flow inside the wake of water droplets sliding on inclined frosted glass. Suggestions are given on how to exploit drainage of the water droplet wake and the high hysteresis of water within the framework of open microfluidics.","PeriodicalId":19791,"journal":{"name":"Papers in Physics","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44709216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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