{ "types" : { "Bookmark" : { "pluralLabel" : "Bookmarks" }, "Publication" : { "pluralLabel" : "Publications" }, "GoldStandardPublication" : { "pluralLabel" : "GoldStandardPublications" }, "GoldStandardBookmark" : { "pluralLabel" : "GoldStandardBookmarks" }, "Tag" : { "pluralLabel" : "Tags" }, "User" : { "pluralLabel" : "Users" }, "Group" : { "pluralLabel" : "Groups" }, "Sphere" : { "pluralLabel" : "Spheres" } }, "properties" : { "count" : { "valueType" : "number" }, "date" : { "valueType" : "date" }, "changeDate" : { "valueType" : "date" }, "url" : { "valueType" : "url" }, "id" : { "valueType" : "url" }, "tags" : { "valueType" : "item" }, "user" : { "valueType" : "item" } }, "items" : [ { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/29b9ab52d022176450550e6b4f6ff7198/simtech", "tags" : [ "PN1","PN6","PN6-9","EXC2075","updated","PN1-10" ], "intraHash" : "9b9ab52d022176450550e6b4f6ff7198", "interHash" : "e18bf2d911e7a20e459e5086d0794c17", "label" : "The method of the approximate inverse for limited-angle CT", "user" : "simtech", "description" : "", "date" : "2026-04-22 12:58:21", "changeDate" : "2026-04-22 12:58:21", "count" : 4, "pub-type": "article", "journal": "Inverse Problems", "year": "2026", "url": "https://doi.org/10.1088/1361-6420/ae5844", "author": [ "Bernadette Hahn","Gael Rigaud","Richard Schmähl" ], "authors": [ {"first" : "Bernadette", "last" : "Hahn"}, {"first" : "Gael", "last" : "Rigaud"}, {"first" : "Richard", "last" : "Schmähl"} ], "abstract": "Limited-angle computerized tomography stands for one of the most difficult challenges in
imaging. Although it opens the way to faster data acquisition in industry and less
dangerous scans in medicine, standard approaches, such as the filtered backprojection
(FBP) algorithm or the widely used total-variation functional, often produce various
artefacts that hinder the diagnosis. With the rise of deep learning, many modern
techniques have proven themselves successful in removing such artefacts but at the cost of
large datasets. In this paper, we propose a new model-driven approach based on the
method of the approximate inverse, which could serve as new starting point for learning
strategies in the future. In contrast to FBP-type approaches, our reconstruction step
consists in evaluating linear functionals on the measured data using reconstruction kernels
that are precomputed as solution of an auxiliary problem. With this problem being
uniquely solvable, the derived limited-angle reconstruction kernel (LARK) is able to fully
reconstruct the object without the well-known streak artefacts, even for large limited
angles. However, it inherits severe ill-conditioning which leads to a different kind of
artefacts arising from the singular functions of the limited-angle Radon transform. The
problem becomes particularly challenging when working on semi-discrete (real or
analytical) measurements. We develop a general regularization strategy by combining
spectral filter, the method of the approximate inverse and custom edge-preserving
denoising in order to stabilize the whole process. We further derive and interpret error
estimates for the application on real, i.e. semi-discrete, data and we validate our approach
on synthetic and real data.", "doi" : "10.1088/1361-6420/ae5844", "bibtexKey": "Hahn_2026" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2efed0d451417420eda0b45da0e04ec35/simtech", "tags" : [ "PN1","PN1-2(II)","EXC2075","updated" ], "intraHash" : "efed0d451417420eda0b45da0e04ec35", "interHash" : "a3449ae4808eb44411e5aefc08f84acf", "label" : "PLIC-based contact line modeling for simulations of droplet impact onto smooth and structured surfaces", "user" : "simtech", "description" : "", "date" : "2026-04-13 09:11:43", "changeDate" : "2026-04-13 09:11:43", "count" : 3, "pub-type": "article", "journal": "International Journal of Multiphase Flow","publisher":"Elsevier BV", "year": "2026", "url": "http://dx.doi.org/10.1016/j.ijmultiphaseflow.2026.105725", "author": [ "Jonathan Wurst","Maximilian Dreisbach","Alexander Stroh","Jochen Kriegseis","Kathrin Schulte" ], "authors": [ {"first" : "Jonathan", "last" : "Wurst"}, {"first" : "Maximilian", "last" : "Dreisbach"}, {"first" : "Alexander", "last" : "Stroh"}, {"first" : "Jochen", "last" : "Kriegseis"}, {"first" : "Kathrin", "last" : "Schulte"} ], "volume": "200","pages": "105725", "issn" : "0301-9322", "doi" : "10.1016/j.ijmultiphaseflow.2026.105725", "bibtexKey": "Wurst_2026" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/20037f0af1b78120cd0be0826df5eeeb3/simtechpuma", "tags" : [ "PN1-4","PN1","PN1-4(II)","EXC2075","selected" ], "intraHash" : "0037f0af1b78120cd0be0826df5eeeb3", "interHash" : "04d3eaf4f8bdd579b4941220a61a0711", "label" : "Towards bespoke gas permeability by functionally graded structures in laser-based powder bed fusion of metals", "user" : "simtechpuma", "description" : "", "date" : "2026-02-16 15:04:58", "changeDate" : "2026-02-16 15:04:58", "count" : 8, "pub-type": "article", "journal": "Additive Manufacturing", "year": "2024", "url": "https://doi.org/10.1016/j.addma.2024.104466", "author": [ "Clemens Maucher","Yeonse Kang","Stefan Bechler","Matthias Ruf","Holger Steeb","Hans-Christian Möhring","Fabian Hampp" ], "authors": [ {"first" : "Clemens", "last" : "Maucher"}, {"first" : "Yeonse", "last" : "Kang"}, {"first" : "Stefan", "last" : "Bechler"}, {"first" : "Matthias", "last" : "Ruf"}, {"first" : "Holger", "last" : "Steeb"}, {"first" : "Hans-Christian", "last" : "Möhring"}, {"first" : "Fabian", "last" : "Hampp"} ], "doi" : "10.1016/j.addma.2024.104466", "bibtexKey": "Maucher2024AM" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/248d0994b3f91749b53dabdd1299eca13/simtechpuma", "tags" : [ "PN1-4","PN1","PN1-4(II)","misc","EXC2075" ], "intraHash" : "48d0994b3f91749b53dabdd1299eca13", "interHash" : "8b0f05df7202491fd1ae5ffdc41895db", "label" : "Direct and Indirect Measurement of Complex Poisson's Ratio - Direct Measurement in Tension", "user" : "simtechpuma", "description" : "", "date" : "2026-02-16 15:04:58", "changeDate" : "2026-02-16 15:04:58", "count" : 6, "pub-type": "misc", "year": "2024", "url": "", "author": [ "Dominik Fauser","Holger Steeb" ], "authors": [ {"first" : "Dominik", "last" : "Fauser"}, {"first" : "Holger", "last" : "Steeb"} ], "note": "Related to: D. Fauser, J. Rodriguez, H. Madadi, J. Haeberle, J. Renner, H. Steeb. 2024. Complex Poisson\u2019s Ratio for Viscoelastic Materials: Direct and IndirectMeasurement Methods and Their Correlation. To be submitted","abstract": "This data set contains directly determined complex Poisson's ratio from axial and transversal strain measurements. Here, the axial and transverse strains were measured locally with strain gauges (K-CXY3-0015-3-350-O, HBK, Darmstadt, Germany) on cylindric polymethyl methacrylate (PMMA, EH-Design, Wörrstadt, Germany) samples with a diameter of d = 5 mm. Frequency measurements were performed with a rheometer (MCR702, linear motor, Anton-Paar, Graz, Austria) in the range of 1 Hz to 100 Hz with an axial strain of 0.01 % at constant temperatures in the range of 15 °C to 105 °C. 500 periods were measured per frequency and recorded using a measuring amplifier (Universal Amplifier MX1615B, HBK, Darmstadt, Germany). Transversal and axial strain is then measured on the PMMA sample with strain gauges in tension mode.The material response in the time domain is transformed to the frequency domain using the Fast Fourier Transform. This gives the axial and transverse amplitude as well as the axial and transverse phase shift. With the variable from the frequency domain, the complex Poisson's ratio is calculated in post-processing.The data set contains the calculated complex Poisson's ratio of three measured PMMA samples.", "affiliation" : "Fauser, Dominik/University of Stuttgart, Institute of Applied Mechanics (CE), Steeb, Holger/University of Stuttgart, Institute of Applied Mechanics (CE) & SC SimTech", "orcid-numbers" : "Fauser, Dominik/0000-0001-7989-9159, Steeb, Holger/0000-0001-7602-4920", "doi" : "10.18419/darus-3588", "bibtexKey": "fauser2024direct" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2709005c72c6262b6ce4a9b34a84ea6a1/simtechpuma", "tags" : [ "PN1","misc","PN1-14","EXC2075" ], "intraHash" : "709005c72c6262b6ce4a9b34a84ea6a1", "interHash" : "5f00467a590eccf5fc9cb228e20d6d80", "label" : "Code for: Seasonal Dynamics of Gaseous CO2 Concentrations in a Karst Cave Correspond With Aqueous Concentrations in a Stagnant Water Column", "user" : "simtechpuma", "description" : "", "date" : "2026-02-16 15:04:58", "changeDate" : "2026-02-16 15:04:58", "count" : 7, "pub-type": "dataset", "publisher":"DaRUS", "year": "2023", "url": "https://darus.uni-stuttgart.de/citation?persistentId=doi:10.18419/darus-3276", "author": [ "Leon Keim","Holger Class","Larissa Schirmer","Bettina Strauch","Kai Wendel","Martin Zimmer" ], "authors": [ {"first" : "Leon", "last" : "Keim"}, {"first" : "Holger", "last" : "Class"}, {"first" : "Larissa", "last" : "Schirmer"}, {"first" : "Bettina", "last" : "Strauch"}, {"first" : "Kai", "last" : "Wendel"}, {"first" : "Martin", "last" : "Zimmer"} ], "abstract": "This dataset contains the DuMux code for the simulations in https://doi.org/10.3390/geosciences13020051 For the detailed list of software used, please have a look at the file install_class2023.sh.", "doi" : "10.18419/DARUS-3276", "bibtexKey": "https://doi.org/10.18419/darus-3276" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/22073e8b3218e3d5ee7981162c98ae063/simtechpuma", "tags" : [ "PN1-4","PN1","PN1-4(II)","EXC2075","selected" ], "intraHash" : "2073e8b3218e3d5ee7981162c98ae063", "interHash" : "5bd0466524169f8e4f735eaa4a7f78fb", "label" : "Modelling and simulation of natural hydraulic fracturing applied to experiments on natural sandstone cores", "user" : "simtechpuma", "description" : "", "date" : "2026-02-16 15:04:58", "changeDate" : "2026-02-16 15:04:58", "count" : 7, "pub-type": "article", "journal": "Acta Geotechnica", "year": "2024", "url": "https://doi.org/10.1007/s11440-024-02351-7", "author": [ "Junxiang Wang","Alixa Sonntag","Dongwon Lee","Giovanna Xotta","Valentina A. Salomoni","Holger Steeb","Arndt Wagner","Wolfgang Ehlers" ], "authors": [ {"first" : "Junxiang", "last" : "Wang"}, {"first" : "Alixa", "last" : "Sonntag"}, {"first" : "Dongwon", "last" : "Lee"}, {"first" : "Giovanna", "last" : "Xotta"}, {"first" : "Valentina A.", "last" : "Salomoni"}, {"first" : "Holger", "last" : "Steeb"}, {"first" : "Arndt", "last" : "Wagner"}, {"first" : "Wolfgang", "last" : "Ehlers"} ], "abstract": "Under in-situ conditions, natural hydraulic fractures (NHF) can occur in permeable rock structures as a result of a rapid decrease of pore water accompanied by a local pressure regression. Obviously, these phenomena are of great interest for the geo-engineering community, as for instance in the framework of mining technologies. Compared to induced hydraulic fractures, NHF do not evolve under an increasing pore pressure resulting from pressing a fracking fluid in the underground but occur and evolve under local pore-pressure reductions resulting in tensile stresses in the rock material. The present contribution concerns the question under what quantitative circumstances NHF emerge and evolve. By this means, the novelty of this article results from the combination of numerical investigations based on the Theory of Porous Media with a tailored experimental protocol applied to saturated porous sandstone cylinders. The numerical investigations include both pre-existing and evolving fractures described by use of an embedded phase-field fracture model. Based on this procedure, representative mechanical and hydraulic loading scenarios are simulated that are in line with experimental investigations on low-permeable sandstone cylinders accomplished in the Porous Media Lab of the University of Stuttgart. The values of two parameters, the hydraulic conductivity of the sandstone and the critical energy release rate of the fracture model, have turned out essential for the occurrence of tensile fractures in the sandstone cores, where the latter is quantitatively estimated by a comparison of experimental and numerical results. This parameter can be taken as reference for further studies of in-situ NHF phenomena and experimental results.", "issn" : "1861-1133", "doi" : "10.1007/s11440-024-02351-7", "bibtexKey": "Wang2024" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2f2224f7d19b31f8849f9792db3b5f351/simtechpuma", "tags" : [ "PN1","misc","PN1-14","EXC2075" ], "intraHash" : "f2224f7d19b31f8849f9792db3b5f351", "interHash" : "af21a060119af0fdc465a181f0c37891", "label" : "Replication Data for: Rayleigh invariance allows the estimation of effective CO2 fluxes due to convective dissolution into water-filled fractures", "user" : "simtechpuma", "description" : "", "date" : "2026-02-16 15:04:58", "changeDate" : "2026-02-16 15:04:58", "count" : 9, "pub-type": "dataset", "publisher":"DaRUS", "year": "2024", "url": "https://darus.uni-stuttgart.de/citation?persistentId=doi:10.18419/darus-4143", "author": [ "Leon Keim","Holger Class" ], "authors": [ {"first" : "Leon", "last" : "Keim"}, {"first" : "Holger", "last" : "Class"} ], "abstract": "This dataset features both data and code related to the research article titled \"Rayleigh Invariance Enables Estimation of Effective CO2 Fluxes Resulting from Convective Dissolution in Water-Filled Fractures.\" It includes raw data packaged in tarball format, including Python scripts used to derive the results presented in the publication. High-resolution raw data for contour plots is available upon request.", "doi" : "10.18419/DARUS-4143", "bibtexKey": "https://doi.org/10.18419/darus-4143" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2c091f0cf33ec38011d10b1cf1d23675d/simtechpuma", "tags" : [ "PN1","PN1-9","misc","EXC2075" ], "intraHash" : "c091f0cf33ec38011d10b1cf1d23675d", "interHash" : "a77ff59f6b35ff08d6fd1e5bf9199e23", "label" : "Weak-Strong Uniqueness and Relaxation Limit for a \nNavier-Stokes-Korteweg Model", "user" : "simtechpuma", "description" : "", "date" : "2026-02-16 15:04:58", "changeDate" : "2026-02-16 15:04:58", "count" : 5, "pub-type": "misc", "year": "2025", "url": "https://arxiv.org/abs/2512.09719", "author": [ "Nilasis Chaudhuri","Christian Rohde","Florian Wendt" ], "authors": [ {"first" : "Nilasis", "last" : "Chaudhuri"}, {"first" : "Christian", "last" : "Rohde"}, {"first" : "Florian", "last" : "Wendt"} ], "eprint" : "2512.09719", "archiveprefix" : "arXiv", "primaryclass" : "math.AP", "bibtexKey": "chaudhuri_rohde_wendt2025" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/28338cc80241800a30f9566c653fb6346/simtechpuma", "tags" : [ "PN1-4","PN1","PN1-4(II)","misc","EXC2075" ], "intraHash" : "8338cc80241800a30f9566c653fb6346", "interHash" : "c55dcd697f26b06f86ae4697fc1c7f14", "label" : "Data for: Formation of common preferential two-phase displacement pathways in porous media", "user" : "simtechpuma", "description" : "", "date" : "2026-02-16 15:04:58", "changeDate" : "2026-02-16 15:04:58", "count" : 5, "pub-type": "misc", "year": "2024", "url": "", "author": [ "Samaneh Vahid Dastjerdi","Nikolaos Karadimitriou","Holger Steeb" ], "authors": [ {"first" : "Samaneh", "last" : "Vahid Dastjerdi"}, {"first" : "Nikolaos", "last" : "Karadimitriou"}, {"first" : "Holger", "last" : "Steeb"} ], "note": "Related to: Vahid Dastjerdi, S.; Karadimitriou, N.; Hassanizadeh, S. M. & Steeb, H.: Formation of common preferential two-phase displacement pathways in porous media. Water Resources Research (Submitted Jan. 2024)","abstract": "With the use of optical microscopy, microfluidic experiments took place in quasi-2D artificial porous media for a variety of cyclic displacement processes and boundary conditions, four of which are shared here. This Dataset contains the data presented in the related publication Vahid Dastjerdi et. al. (2024). Each experiment is flow-controlled and has a different flow rate. Three of the experiments include 12, 21, or 24 sequential displacement events. The images and pressures recorded during the experiments are presented. Due to some technical issues, pressure values for experiment 2 are not available.", "affiliation" : "Vahid Dastjerdi, Samaneh/Institute for Applied Mechanics (CE) & SC SimTech, University of Stuttgart, Karadimitriou, Nikolaos/Institute for Applied Mechanics (CE) & SC SimTech, University of Stuttgart, Steeb, Holger/Institute for Applied Mechanics (CE) & SC SimTech, University of Stuttgart", "orcid-numbers" : "Vahid Dastjerdi, Samaneh/0000-0003-0315-4067, Karadimitriou, Nikolaos/0000-0002-9461-6214, Steeb, Holger/0000-0001-7602-4920", "doi" : "10.18419/darus-3358", "bibtexKey": "vahiddastjerdi2024formation" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2f9b30508ea3914aa79fe1d69241c33d9/simtechpuma", "tags" : [ "PN1-4","PN1","PN1-4(II)","misc","EXC2075" ], "intraHash" : "f9b30508ea3914aa79fe1d69241c33d9", "interHash" : "12d2e2effbd0d795f80f991795ba7686", "label" : "Direct and Indirect Measurement of Complex Poisson's Ratio - Indirect Measurement in Torsion and Tension", "user" : "simtechpuma", "description" : "", "date" : "2026-02-16 15:04:58", "changeDate" : "2026-02-16 15:04:58", "count" : 6, "pub-type": "misc", "year": "2024", "url": "", "author": [ "Dominik Fauser","José Alberto Rodríguez Agudo","Holger Steeb" ], "authors": [ {"first" : "Dominik", "last" : "Fauser"}, {"first" : "José Alberto", "last" : "Rodríguez Agudo"}, {"first" : "Holger", "last" : "Steeb"} ], "note": "Related to: D. Fauser, J. Rodriguez, H. Madadi, J. Haeberle, J. Renner, H. Steeb. 2024. Complex Poisson\u2019s Ratio for Viscoelastic Materials: Direct and IndirectMeasurement Methods and Their Correlation. To be submitted","abstract": "This data set contains indirectly calculated complex Poisson's ratio by determining the complex Young's E* and complex shear modulus G* from torsion and tension measurements. The measurements were performed on cylindric polymethyl methacrylate (PMMA, EH-Design, Wörrstadt, Germany) samples with a diameter of d = 3 mm. Frequency measurements were performed with a rheometer (MCR 702, linear motor, Anton-Paar, Graz, Austria) in a angular frequency range of 0.628 rad/s to 188 rad/s with an axial strain of epsilon = 0.01 % and shear strain of gamma = 0.01 % at constant temperatures in the range of 15 to 105 °C. The Elastic Viscoelastic Correspondence Principle (EVCP) is applied to calculate the complex Poisson's ratio.", "affiliation" : "Fauser, Dominik/University of Stuttgart, Institute of Applied Mechanics (CE), Rodríguez Agudo, José Alberto/Anton Paar Germany GmbH, Steeb, Holger/University of Stuttgart, Institute of Applied Mechanics (CE) & SC SimTech", "orcid-numbers" : "Fauser, Dominik/0000-0001-7989-9159, Rodríguez Agudo, José Alberto/0000-0003-0025-6252, Steeb, Holger/0000-0001-7602-4920", "doi" : "10.18419/darus-3590", "bibtexKey": "fauser2024direct" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/213b334fea9f09b1e300a4f272731e0ec/simtechpuma", "tags" : [ "PN1-4","PN1","PN1-4(II)","EXC2075","selected" ], "intraHash" : "13b334fea9f09b1e300a4f272731e0ec", "interHash" : "a500f1c4ce38f04de562be7fac81faa3", "label" : "On the macro- and micro-scale of dilute suspensions : A particle-based numerical investigation", "user" : "simtechpuma", "description" : "", "date" : "2026-02-16 15:04:58", "changeDate" : "2026-02-16 15:04:58", "count" : 6, "pub-type": "article", "journal": "European journal of mechanics. B, Fluids","publisher":"Elsevier", "year": "2024", "url": "", "author": [ "Nadine Kijanski","Holger Steeb" ], "authors": [ {"first" : "Nadine", "last" : "Kijanski"}, {"first" : "Holger", "last" : "Steeb"} ], "volume": "103","number": "January/February","pages": "208-222", "research-areas" : "Mechanics; Physics", "language" : "eng", "issn" : "0997-7546 and 1873-7390", "affiliation" : "Kijanski, N (Corresponding Author), Univ Stuttgart, Inst Appl Mech CE, Pfaffenwaldring 7, D-70569 Stuttgart, Germany.\n Kijanski, Nadine, Univ Stuttgart, Inst Appl Mech CE, Pfaffenwaldring 7, D-70569 Stuttgart, Germany.\n Stuttgart Ctr Simulat Sci, Pfaffenwaldring 5a, D-70569 Stuttgart, Germany.", "unique-id" : "WOS:001098249400001", "bibtexKey": "kijanski2024macro" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2634bfe0754d4f84b5ea80d92f8809d24/simtechpuma", "tags" : [ "PN1-4","PN1","PN1-4(II)","misc","EXC2075" ], "intraHash" : "634bfe0754d4f84b5ea80d92f8809d24", "interHash" : "211302c65f4fd76463c1b12070d98677", "label" : "Image processing code for characterization of multiphase flow in porous media", "user" : "simtechpuma", "description" : "", "date" : "2026-02-16 15:04:58", "changeDate" : "2026-02-16 15:04:58", "count" : 5, "pub-type": "misc", "year": "2024", "url": "", "author": [ "Samaneh Vahid Dastjerdi","Holger Steeb" ], "authors": [ {"first" : "Samaneh", "last" : "Vahid Dastjerdi"}, {"first" : "Holger", "last" : "Steeb"} ], "note": "Related to: Vahid Dastjerdi, S.; Karadimitriou, N.; Hassanizadeh, S. M. & Steeb, H.: Experimental evaluation of fluid connectivity in two-phase flow in porous media during drainage. Water Resources Research 58 (2022), e2022WR033451. doi: 10.1029/2022WR033451","abstract": "This work utilizes microfluidic experiments to gather data captured as snapshots during the experiments. These snapshots provide real-time information and undergo image processing to derive the required data. Image processing involves several steps tailored to the investigations: Making a reference image (mask): This process involves creating a reference image, or mask, to document the initial conditions. For instance, the porous domain is imaged when saturated with one phase to differentiate various areas containing different phases. Reading and cutting images: Images showing changes in fluid volume fraction are selectively chosen and processed. Each image is read into MATLAB, and the area of interest is extracted. Image segmentation: Labeling each pixel of the images is done via thresholding and edge detection. Measuring parameters: Parameters like saturation, interfacial length, area, contact angle, and curvature are measured. These parameters play a crucial role in analyzing the experiments. The interfacial area is calculated through various formulations. Calculating capillary pressure: Several forms of capillary pressure are calculated using information derived from the experiments. REV-Scale Quantities: Parameters are upscaled to represent Representative Elementary Volume (REV)-scale values essential for continuum theories. REV-scale capillary pressure is derived from pore-scale values using appropriate averaging techniques.", "affiliation" : "Vahid Dastjerdi, Samaneh/Institute of Applied Mechanics (CE) & SC SimTech, University of Stuttgart, Steeb, Holger/Institute of Applied Mechanics (CE) & SC SimTech, University of Stuttgart", "orcid-numbers" : "Vahid Dastjerdi, Samaneh/0000-0003-0315-4067, Steeb, Holger/0000-0001-7602-4920", "doi" : "10.18419/darus-4153", "bibtexKey": "vahiddastjerdi2024image" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/24f6272dacff0a8b7d70a21c5cab4bb0d/simtechpuma", "tags" : [ "PN1-4","PN1","PN1-4(II)","misc","EXC2075" ], "intraHash" : "4f6272dacff0a8b7d70a21c5cab4bb0d", "interHash" : "9ed24f75b1aa449f6d403b7ae80c2b77", "label" : "In situ micro-XRCT data set of an open-cell polyurethane foam sample under uniaxial compression load", "user" : "simtechpuma", "description" : "", "date" : "2026-02-16 15:04:58", "changeDate" : "2026-02-16 15:04:58", "count" : 6, "pub-type": "misc", "year": "2024", "url": "", "author": [ "Matthias Ruf","Holger Steeb" ], "authors": [ {"first" : "Matthias", "last" : "Ruf"}, {"first" : "Holger", "last" : "Steeb"} ], "note": "Related to: Ruf, M., Steeb, H., & Karadimitriou, N. (2023). Visualization of the uniaxial compression of open-cell foams. In Médici, E.F., & Otero, A.D. (eds.): Album of Porous Media, Springer International Publishing, Cham, Switzerland, 117-117. doi: 10.1007/978-3-031-23800-0_97","abstract": "This dataset contains seven micro X-Ray Computed Tomography (micro-XRCT) scan data sets (projection, reconstructed, and segmented images, respectively) of an open-cell reticulated Polyurethane (PUR) foam specimen with 10 pores per inch under different uniaxial deformation states. The initial diameter and length of the unloaded cylindrical sample are 52 mm and 50 mm. The sample was glued on two aluminum sample holders. Scans of the sample were performed for seven successive time steps (t0, t1, t2, t3, t4, t5, t6) under uniaxial displacements of 0, 5, 10, 15, 20, 25, 0 mm imposed at the bottom part of the sample (fixed upper sample holder). Before starting the image acquisition at the different deformation states, the sample was relaxed for 20 min each time. The relaxation curves (including relaxation during the scan) are provided in the files \"t*_utm_data.csv\". The scans were performed displacement-controlled.The image data sets are labeled according to the time step the micro-XRCT scan was performed (t0, t1, t2, t3, t4, t5, t6) followed by a specification of the image data set (\"_projections\", \"_reconstructed\", \"_segmented\"). Due to an eccentricity error between the upper and lower rotational table, compensation in the reconstruction was necessary. That was restricted to the foam part and not to the sample holders. Besides the projection images and the 3d reconstructed images, segmented images (into foam skeleton and void space) are provided. To reduce the data size, the foam sample was extracted by a cylinder of 52.36 diameter. Due to strong beam hardening in the aluminum sample holders, superimposed with cone-beam angle artifacts in those areas, and additional contaminated foam by the used glue in the transition region, only 44.26 mm in the axial direction of the foam sample at t0 (undeformed state) is given. For all other deformation states, the first and last slices of the segmented image stacks correspond roughly to them.After the image acquisition and a sufficiently long relaxation of the sample, a uniaxial compression test up to 30 mm maximum displacement was performed using the same sample. Loading/unloading was performed displacement controlled with |0.5| mm/s. The data is provided in the file \"utm_data.csv\".", "affiliation" : "Ruf, Matthias/University of Stuttgart, Institute of Applied Mechanics (CE), Steeb, Holger/University of Stuttgart, Institute of Applied Mechanics (CE) & SC SimTech", "orcid-numbers" : "Ruf, Matthias/0000-0003-0299-5921, Steeb, Holger/0000-0001-7602-4920", "doi" : "10.18419/darus-3010", "bibtexKey": "ruf2024microxrct" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2d42fc0ab5d6a88c0cffb25979392ae21/simtechpuma", "tags" : [ "PN1-4","PN1","PN1-4(II)","misc","EXC2075" ], "intraHash" : "d42fc0ab5d6a88c0cffb25979392ae21", "interHash" : "758ce45c4c73dff3eb736709714dc18f", "label" : "Primary drainage experiments and fractal dimensions", "user" : "simtechpuma", "description" : "", "date" : "2026-02-16 15:04:58", "changeDate" : "2026-02-16 15:04:58", "count" : 6, "pub-type": "misc", "year": "2024", "url": "", "author": [ "Nikolaos Karadimitriou","Dongwon Lee","Samaneh Vahid Dastjerdi","Holger Steeb" ], "authors": [ {"first" : "Nikolaos", "last" : "Karadimitriou"}, {"first" : "Dongwon", "last" : "Lee"}, {"first" : "Samaneh", "last" : "Vahid Dastjerdi"}, {"first" : "Holger", "last" : "Steeb"} ], "abstract": "The current repository contains raw data in the shape of images collected during a systematic laboratory study, examining the usability of the fractal dimension in the characterization of the flow regime. The study is presented in the paper by Karadimitriou et al., 2024. The two fluids were the wetting phase (WP), FluorinertTM, FC-43, and the non-wetting phase (NWP), deionized water mixed with ink, and occasionally with a specific amount of Glycerol. The wetting phase was initially introduced into the pore space of a Poly-Di-Methyl-Siloxane (PDMS) micromodel, fully saturating it. Then, primary drainage scenarios were realized with the introduction of the non-wetting phase under controlled-flux conditions. The objective of the study was to investigate the usability of the fractal dimension of various geometrical entities, like the interfaces between phases, and the bulk non-wetting phase occupancy of the pore space, in the characterization of the flow regime. Main data: The dataset is populated with the raw images acquired during a primary drainage process. Every drainage process took place under a fixed boundary volumetric flux, which is depicted in the title of each file, in terms of the corresponding capillary number. Additionally, the title of each file also includes the viscosity ratio between the invading and the defending phase. A typical file name is in the form Ca=***,M=***.tar. In the images, the non-wetting phase, namely water, shows as dark, and the wetting phase, namely Fluorinert, shows as transparent within the boundaries of the pore network. Flow takes place from right to left. Procedure followed for each constant Ca and M experiment: The term \u201Cexperiment\u201D pertains to the breakthrough of the non-wetting phase from its own inlet to the outlet, at a constant boundary flux. For every experiment, a fixed capillary number value, Cai, i = 1,2,3, is maintained, whereas the viscosity ratio between the invading and the defending phase remains the same through a single experiment. In order for the viscosity ratio to be fixed on demand, Glycerol was added to water at specific concentrations, so as to achieve the desired viscosity of water. The Ca used were 10-2, 10-3, 10-4, and 10-5. The viscosity ratios used were 0.2, 1, and 10. The flow network has overall dimensions of 15 by 20 millimeters, with a mean pore size of 410 microns, and a depth of 100 microns. It is an exact replication of the network used in the work of Sivanesapillai et al., 2018. The micromodel is initially saturated with the wetting phase. Then, the non-wetting phase is injected into the microfluidic pore network. The non-wetting phase is injected at a fixed volumetric flux to maintain a constant value of the capillary number, Ca, during the entire experiment. The wetting phase is getting passively displaced during this process. Even though the experiment, for the needs of the corresponding publication, concludes at breakthrough, some more images are acquired for future purposes.", "affiliation" : "Karadimitriou, Nikolaos/University of Stuttgart, Lee, Dongwon/University of Stuttgart, Vahid Dastjerdi, Samaneh/University of Stuttgart, Steeb, Holger/University of Stuttgart", "orcid-numbers" : "Karadimitriou, Nikolaos/0000-0002-9461-6214, Lee, Dongwon/0000-0003-4826-1632, Vahid Dastjerdi, Samaneh/0000-0003-0315-4067, Steeb, Holger/0000-0001-7602-4920", "doi" : "10.18419/darus-4114", "bibtexKey": "karadimitriou2024primary" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2b77a4e5af36a9c7edbb4c7a0157740f1/simtechpuma", "tags" : [ "PN1","misc","PN1-14","EXC2075" ], "intraHash" : "b77a4e5af36a9c7edbb4c7a0157740f1", "interHash" : "0236e13613439e60bc74e229afc65590", "label" : "Replication Code for: Rayleigh invariance allows the estimation of effective CO2 fluxes due to convective dissolution into water-filled fractures", "user" : "simtechpuma", "description" : "", "date" : "2026-02-16 15:04:58", "changeDate" : "2026-02-16 15:04:58", "count" : 9, "pub-type": "dataset", "publisher":"DaRUS", "year": "2024", "url": "https://darus.uni-stuttgart.de/citation?persistentId=doi:10.18419/darus-4089", "author": [ "Leon Keim","Holger Class" ], "authors": [ {"first" : "Leon", "last" : "Keim"}, {"first" : "Holger", "last" : "Class"} ], "abstract": "This dataset consists of software code associated with the publication titled \"Rayleigh Invariance Enables Estimation of Effective CO2 Fluxes Resulting from Convective Dissolution in Water-Filled Fractures.\" It includes a Dockerimage that contains the precompiled code for immediate use. For transparency, the Dockerfile is also provided.", "doi" : "10.18419/DARUS-4089", "bibtexKey": "https://doi.org/10.18419/darus-4089" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2ebb4f1f822fa2ffda0f700516148158e/simtechpuma", "tags" : [ "PN1-4","PN1","PN1-4(II)","EXC2075","selected" ], "intraHash" : "ebb4f1f822fa2ffda0f700516148158e", "interHash" : "9fd23811a166ae3c9914ebf859ae1c86", "label" : "Development of stochastically reconstructed 3D porous media micromodels using additive manufacturing: numerical and experimental validation", "user" : "simtechpuma", "description" : "", "date" : "2026-02-16 15:04:58", "changeDate" : "2026-02-16 15:04:58", "count" : 9, "pub-type": "article", "journal": "Scientific Reports", "year": "2024", "url": "https://doi.org/10.1038/s41598-024-60075-w", "author": [ "Dongwon Lee","Matthias Ruf","Nikolaos Karadimitriou","Holger Steeb","Mary Manousidaki","Emmanouil A. Varouchakis","Stelios Tzortzakis","Andreas Yiotis" ], "authors": [ {"first" : "Dongwon", "last" : "Lee"}, {"first" : "Matthias", "last" : "Ruf"}, {"first" : "Nikolaos", "last" : "Karadimitriou"}, {"first" : "Holger", "last" : "Steeb"}, {"first" : "Mary", "last" : "Manousidaki"}, {"first" : "Emmanouil A.", "last" : "Varouchakis"}, {"first" : "Stelios", "last" : "Tzortzakis"}, {"first" : "Andreas", "last" : "Yiotis"} ], "volume": "14","number": "1","pages": "9375--","abstract": "We propose an integrated methodology for the design and fabrication of 3D micromodels that are suitable for the pore-scale study of transport processes in macroporous materials. The micromodels, that bear the pore-scale characteristics of sandstone, such as porosity, mean pore size, etc, are designed following a stochastic reconstruction algorithm that allows for fine-tuning the porosity and the correlation length of the spatial distribution of the solid material. We then construct a series of 3D micromodels at very fine resolution (i.e. $$16\\,$$m) using a state-of-the-art 3D printing infrastructure, specifically a ProJet MJP3600 3D printer, that utilizes the Material Jetting technology. Within the technical constraints of the 3D printer resolution, the fabricated micromodels represent scaled-up replicas of natural sandstones, that are suitable for the study of the scaling between the permeability, the porosity and the mean pore size. The REV- and pore-scale characteristics of the resulting physical micromodels are recovered using a combination of X-ray micro-CT and microfluidic studies. The experimental results are then compared with single-phase flow simulations at pore-scale and geostatistic models in order to determine the effects of the design parameters on the intrinsic permeability and the spatial correlation of the velocity profile. Our numerical and experimental measurements reveal an excellent match between the properties of the designed and fabricated 3D domains, thus demonstrating the robustness of the proposed methodology for the construction of 3D micromodels with fine-tuned and well-controlled pore-scale characteristics. Furthermore, a pore-scale numerical study over a wider range of 3D digital domain realizations reveals a very good match of the measured permeabilities with the predictions of the Kozeny\u2013Carman formulation based on a single control parameter, $$k_0$$, that is found to have a practically constant value for porosities $$0.2$$. This, in turn, enables us to customize the sample size to meet REV constraints, including enlarging pore morphology while considering the Reynolds number. It is also found that at lower porosities there is a significant increase in the fraction of the non-percolating pores, thus leading to different $$k_0$$, as the porosity approaches a numerically determined critical porosity value, $$_c$$, where the domain is no longer percolating.", "issn" : "20452322", "refid" : "Lee2024", "doi" : "10.1038/s41598-024-60075-w", "bibtexKey": "lee2024development" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2b2352aa5e52e10e4f591b687a0de7509/simtechpuma", "tags" : [ "unclear","PN1-4","PN1","PN1-4(II)","EXC2075" ], "intraHash" : "b2352aa5e52e10e4f591b687a0de7509", "interHash" : "127815b12713770c0896858dcc0184f6", "label" : "Supraglacial lake drainage through gullies and fractures", "user" : "simtechpuma", "description" : "", "date" : "2026-02-16 15:04:58", "changeDate" : "2026-02-16 15:04:58", "count" : 6, "pub-type": "article", "publisher":"Copernicus GmbH", "year": "2024", "url": "http://dx.doi.org/10.5194/egusphere-egu24-16416", "author": [ "Angelika Humbert","Veit Helm","Ole Zeising","Niklas Neckel","Robert Salzano","Giulio Esposito","Matthias Braun","Holger Steeb","Julia Sohn","Matthias Bohnen","Ralf Müller","Martin Rückamp" ], "authors": [ {"first" : "Angelika", "last" : "Humbert"}, {"first" : "Veit", "last" : "Helm"}, {"first" : "Ole", "last" : "Zeising"}, {"first" : "Niklas", "last" : "Neckel"}, {"first" : "Robert", "last" : "Salzano"}, {"first" : "Giulio", "last" : "Esposito"}, {"first" : "Matthias", "last" : "Braun"}, {"first" : "Holger", "last" : "Steeb"}, {"first" : "Julia", "last" : "Sohn"}, {"first" : "Matthias", "last" : "Bohnen"}, {"first" : "Ralf", "last" : "Müller"}, {"first" : "Martin", "last" : "Rückamp"} ], "bemerkung" : "Journal fehlt", "doi" : "10.5194/egusphere-egu24-16416", "bibtexKey": "Humbert_2024" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/276c8ddcd8acc53b814a3853e4d061c66/simtechpuma", "tags" : [ "PN1-4","PN1","PN1-4(II)","EXC2075","selected" ], "intraHash" : "76c8ddcd8acc53b814a3853e4d061c66", "interHash" : "f7c904331215eb608e867a91b3e8b572", "label" : "Exploring carbonate rock dissolution dynamics and the influence of rock mineralogy in CO2 injection", "user" : "simtechpuma", "description" : "", "date" : "2026-02-16 15:04:58", "changeDate" : "2026-02-16 15:04:58", "count" : 9, "pub-type": "article", "journal": "Environmental Science & Technology","publisher":"American Chemical Society (ACS)", "year": "2024", "url": "http://dx.doi.org/10.1021/acs.est.3c06758", "author": [ "Javad Shokri","Matthias Ruf","Dongwon Lee","Saleh Mohammadrezaei","Holger Steeb","Vahid Niasar" ], "authors": [ {"first" : "Javad", "last" : "Shokri"}, {"first" : "Matthias", "last" : "Ruf"}, {"first" : "Dongwon", "last" : "Lee"}, {"first" : "Saleh", "last" : "Mohammadrezaei"}, {"first" : "Holger", "last" : "Steeb"}, {"first" : "Vahid", "last" : "Niasar"} ], "volume": "58","number": "6","pages": "2728\u20132738", "issn" : "1520-5851", "doi" : "10.1021/acs.est.3c06758", "bibtexKey": "Shokri_2024" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2db042439e6ca6e40efa9840e9ad333f2/simtechpuma", "tags" : [ "PN1-4","PN1","PN1-4(II)","EXC2075","selected" ], "intraHash" : "db042439e6ca6e40efa9840e9ad333f2", "interHash" : "d48cc1062240c4dbe26b2f875a2f6397", "label" : "Formation of Common Preferential Two-Phase Displacement Pathways in Porous Media", "user" : "simtechpuma", "description" : "", "date" : "2026-02-16 15:04:58", "changeDate" : "2026-02-16 15:04:58", "count" : 6, "pub-type": "article", "journal": "Water Resources Research", "year": "2024", "url": "https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2024WR037266", "author": [ "Samaneh Vahid Dastjerdi","Nikolaos Karadimitriou","S. Majid Hassanizadeh","Holger Steeb" ], "authors": [ {"first" : "Samaneh", "last" : "Vahid Dastjerdi"}, {"first" : "Nikolaos", "last" : "Karadimitriou"}, {"first" : "S. Majid", "last" : "Hassanizadeh"}, {"first" : "Holger", "last" : "Steeb"} ], "volume": "60","number": "12","pages": "e2024WR037266","note": "e2024WR037266 2024WR037266","abstract": "Abstract Including specific interfacial area and saturation of the percolating phase into two-phase porous media flow models, on the Darcy scale, enhances our ability to capture the physical properties of porous media flow more effectively. Using optical microscopy and microfluidic devices, we perform sequential drainage and imbibition experiments. The relevant processes, images, and boundary pressures are monitored, recorded, and logged at all times. For comparative purposes, two PDMS micromodels are used, one with an ortho-canonical, homogeneous, and the other with a periodic heterogeneous pore network, with similar macro- but different pore-scale properties. After processing the images, parameters like interfacial area belonging to percolating and non-percolating phases and the corresponding phase saturations are determined. Our experimental results show that the relation between specific interfacial area and saturation of the percolating invading phase is a linear relationship with interesting properties. Additionally, after a number of fluid displacement processes (drainage and imbibition), and for both pore networks, unique flow paths for both phases are formed. We speculate that this happens due to the establishment of an effective porous medium, meaning a hydro-dynamically active region within the pore space where the corresponding phase remains connected and flowing, where the capillary forces act as the guide for creating the \u201Cpath of least resistance\u201D in a highly viscous flow regime by keeping the non-percolating phases in place. As the results can be specific to our experiments, more work needs to be done toward the potential generalization of these findings, especially in 3D flow domains.", "eprint" : "https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2024WR037266", "doi" : "https://doi.org/10.1029/2024WR037266", "bibtexKey": "https://doi.org/10.1029/2024WR037266" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/21b6411b822157af141d8a76b780314b1/simtechpuma", "tags" : [ "PN1","PN1-9","misc","EXC2075" ], "intraHash" : "1b6411b822157af141d8a76b780314b1", "interHash" : "1ee6bc65d23f08ce49038b9319cfb27a", "label" : "Effective Equations for a Compressible Liquid-Vapor Flow \nModel with Highly Oscillating Initial Density", "user" : "simtechpuma", "description" : "", "date" : "2026-02-09 16:44:25", "changeDate" : "2026-02-09 16:44:25", "count" : 5, "pub-type": "misc", "year": "2025", "url": "https://arxiv.org/abs/2512.15535", "author": [ "Christian Rohde","Florian Wendt" ], "authors": [ {"first" : "Christian", "last" : "Rohde"}, {"first" : "Florian", "last" : "Wendt"} ], "eprint" : "2512.15535", "archiveprefix" : "arXiv", "primaryclass" : "math.AP", "bibtexKey": "EffectiveEquations25" } ] }