103 results match your criteria: "Karlsruhe University[Affiliation]"

Engineers, geomorphologists, and ecologists acknowledge the need for temporally and spatially resolved measurements of sediment clogging (also known as colmation) in permeable gravel-bed rivers due to its adverse impacts on water and habitat quality. In this paper, we present a novel method for non-destructive, real-time measurements of pore-scale sediment deposition and monitoring of clogging by using wire-mesh sensors (WMSs) embedded in spheres, forming a smart gravel bed (GravelSens). The measuring principle is based on one-by-one voltage excitation of transmitter electrodes, followed by simultaneous measurements of the resulting current by receiver electrodes at each crossing measuring pores.

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Remote assessment of physical fitness via videoconferencing: a systematic review.

BMC Sports Sci Med Rehabil

January 2025

Institute of Movement and Sport, Karlsruhe University of Education, Bismarckstraße 10, 76133, Karlsruhe, Germany.

Physical fitness is a critical marker of overall health across all age groups, influencing longevity and quality of life. This systematic review assessed the use of remote physical fitness assessments, a crucial adaptation during the COVID-19 pandemic that broadened access to health monitoring outside traditional settings. The review included 35 studies, covering various age groups and health conditions, and evaluated 48 physical fitness tests across eight physical fitness components.

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Wetting Phenomena: Line Tension and Gravitational Effect.

Phys Rev Lett

December 2024

Institute for Applied Materials - Microstructure Modelling and Simulation (IAM-MMS), Karlsruhe Institute of Technology (KIT), Strasse am Forum 7, 76131 Karlsruhe, Germany; Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany; and Institute of Digital Materials Science, Karlsruhe University of Applied Sciences, Moltkestrasse 30, 76133 Karlsruhe, Germany.

An apparent contact angle is formed when a droplet is deposited on a solid substrate. Young's law has been employed to describe the equilibrium contact angle. Often in experiments, the equilibrium contact angle deviates from Young's law and depends on the volume of the droplet, known as the line tension effect.

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Article Synopsis
  • The study aimed to compare the effectiveness and safety of two preventive treatments for chronic migraines: anti-calcitonin gene-related peptide (anti-CGRP) and botulinum neurotoxin (BoNT), involving 80 patients at King Fahad University Hospital.
  • Both treatments resulted in significant decreases in migraine pain scores and disability after 9 months, with anti-CGRP showing slightly better results, though not statistically significant.
  • Adverse effects were common in both groups, with "headache" being the most frequent; notably, more patients in the anti-CGRP group reported joint stiffness compared to those receiving BoNT.
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Exploration of contact angle hysteresis mechanisms: From microscopic to macroscopic.

J Chem Phys

November 2024

Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz Pl. 1, 76344 Eggenstein-Leopoldshafen, Germany.

Variations from equilibrium Young's angle, known as contact angle hysteresis (CAH), are frequently observed upon droplet deposition on a solid surface. This ubiquitous phenomenon indicates the presence of multiple local surface energy minima for the sessile droplet. Previous research primarily explains CAH via considering macroscopic roughness, such as topographical defects, which alter the effective interfacial energy between the fluid phase and the solid phase, thereby shifting the global surface energy minimum.

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Wetting phenomena of droplets and gas bubbles: Contact angle hysteresis based on varying liquid-solid and solid-gas interfacial tensions.

J Chem Phys

October 2024

Institute of Applied Materials-Microstructure Modelling and Simulation, Karlsruhe Institute of Technology, Straße am Forum 7, 76131 Karlsruhe, Germany.

Wetting phenomena have been widely observed in our daily lives, such as dew on lotus leaf, and applied in technical applications, e.g., ink-jet printing.

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Chemo-elasto-electro free energy of non-uniform system in the diffuse interface context.

J Phys Condens Matter

September 2024

Institute of Applied Materials-Microstructure Modelling and Simulation, Karlsruhe Institute of Technology (KIT), Straße am Forum 7, 76131 Karlsruhe, Germany.

Article Synopsis
  • Proposes a new method for deriving the free energy formulation of non-uniform systems, which offers a clearer understanding of energy contributions including entropy and internal energy.
  • Reformulates local composition within the interface region, leading to formal expressions for various energy types that depend on both composition and its gradients, integrating these to create a comprehensive free energy expression.
  • Addresses limitations in applying this approach to non-uniform fluids in contact with solid substrates by redefining wall free energy based on average composition, sidestepping issues with modeling composition variation across interfaces.
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Electric-field induced phase separation and dielectric breakdown in leaky dielectric mixtures: Thermodynamics and kinetics.

J Chem Phys

July 2024

Institute of Applied Materials-Microstructure Modelling and Simulation, Karlsruhe Institute of Technology, Straße am Forum 7, 76131 Karlsruhe, Germany.

Dielectric materials form the foundation of many electronic devices. When connected to a circuit, these materials undergo changes in microscopic morphology, such as the demixing of dielectric mixtures through phase separation and dielectric breakdown, resulting in the formation of micro-filaments. Consequently, the macroscopic properties and lifespan of the devices are significantly altered.

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Wetting Effect Induced Depletion and Adsorption Layers: Diffuse Interface Perspective.

Chemphyschem

July 2024

Institute of Applied Materials-Microstructure Modelling and Simulation, Karlsruhe Institute of Technology, Straße am Forum 7, 76131, Karlsruhe, Germany.

When a multi-component fluid contacts arigid solid substrate, the van der Waals interaction between fluids and substrate induces a depletion/adsorption layer depending on the intrinsic wettability of the system. In this study, we investigate the depletion/adsorption behaviors of A-B fluid system. We derive analytical expressions for the equilibrium layer thickness and the equilibrium composition distribution near the solid wall, based on the theories of de Gennes and Cahn.

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Wetting and Contact-Angle Hysteresis: Density Asymmetry and van der Waals Force.

Phys Rev Lett

March 2024

Institute for Applied Materials-Microstructure Modelling and Simulation (IAM-MMS), Karlsruhe Institute of Technology (KIT), Strasse am Forum 7, 76131 Karlsruhe, Germany; Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany and Institute of Digital Materials Science, Karlsruhe University of Applied Sciences, Moltkestrasse 30, 76133 Karlsruhe, Germany.

A droplet depositing on a solid substrate leads to the wetting phenomenon, such as dew on plant leaves. On an ideally smooth substrate, the classic Young's law has been employed to describe the wetting effect. However, no real substrate is ideally smooth at the microscale.

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Are realistic details important for learning with visualizations or can depth cues provide sufficient guidance?

Cogn Process

August 2024

Digital Education, Institute for Informatics and Digital Education, Karlsruhe University of Education, Bismarckstr. 10, 76133, Karlsruhe, Germany.

The optimal choice of the level of realism in instructional visualizations is a difficult task. Previous studies suggest that realism can overwhelm learners, but a growing body of research demonstrates that realistic details can enhance learning. In the first experiment (n = 107), it was assessed whether learning using realistic visualizations can be distracting and therefore particularly benefits from pre-training.

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Brownian motion of droplets induced by thermal noise.

Phys Rev E

February 2024

Institute of Applied Materials-Microstructure Modelling and Simulation, Karlsruhe Institute of Technology (KIT), Strasse am Forum 7, 76131 Karlsruhe, Germany.

Brownian motion (BM) is pivotal in natural science for the stochastic motion of microscopic droplets. In this study, we investigate BM driven by thermal composition noise at submicro scales, where intermolecular diffusion and surface tension both are significant. To address BM of microscopic droplets, we develop two stochastic multiphase-field models coupled with the full Navier-Stokes equation, namely, Allen-Cahn-Navier-Stokes and Cahn-Hilliard-Navier-Stokes.

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Revealing process and material parameter effects on densification via phase-field studies.

Sci Rep

March 2024

Institute for Manufacturing Technology of Ceramic Components and Composites, University of Stuttgart, Allmandring 7B, 70569, Stuttgart, Germany.

Sintering is an important processing step in both ceramics and metals processing. The microstructure resulting from this process determines many materials properties of interest. Hence the accurate prediction of the microstructure, depending on processing and materials parameters, is of great importance.

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In inkjet printing technology, one important factor influencing the printing quality and reliability of printed films is the interaction of the jetted ink with the substrate surface. This short-range interaction determines the wettability and the adhesion of the ink to the solid surface and is hence responsible for the final shape of the deposited ink. Here, we investigate wetting morphologies of inkjet-printed inks on patterned substrates by carefully designed experimental test structures and simulations.

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Internal Rotation Measurement of the Knee with Polymer-Based Capacitive Strain Gauges versus Mechanical Rotation Measurement Taking Gender Differences into Account: A Comparative Analysis.

Life (Basel)

January 2024

G.E.R.N. Tissue Replacement, Regeneration & Neogenesis, Department of Orthopedics and Trauma Surgery, Medical Center-Albert-Ludwigs-University of Freiburg, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Engesser Straße 4, 79108 Freiburg, Germany.

With the conventional mechanical rotation measurement of joints, only static measurements are possible with the patient at rest. In the future, it would be interesting to carry out dynamic rotation measurements, for example, when walking or participating in sports. Therefore, a measurement method with an elastic polymer-based capacitive measuring system was developed and validated.

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Evolution dynamics of thin liquid structures investigated using a phase-field model.

Soft Matter

February 2024

Institute for Applied Materials - Microstructure Modelling and Simulation (IAM-MMS), Karlsruhe Institute of Technology (KIT), Straße am Forum 7, Karlsruhe 76131, Germany.

Liquid structures of thin-films and torus droplets are omnipresent in daily lives. The morphological evolution of liquid structures suspending in another immiscible fluid and sitting on a solid substrate is investigated by using three-dimensional (3D) phase-field (PF) simulations. Here, we address the evolution dynamics by scrutinizing the interplay of surface energy, kinetic energy, and viscous dissipation, which is characterized by Reynolds number Re and Weber number We.

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Understanding the response of date palm ( L.) cultivars to salt stress is essential for the sustainable management of phoeniculture in Tafilalet, Morocco. It offers a promising avenue for addressing the challenges presented by the increasing salinity of irrigation waters, especially because farmers in these regions often lack the necessary knowledge and resources to make informed decisions regarding cultivar selection.

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The low-fouling propensity of commercially available polyethersulfone (PES) membranes was studied after modification of the membrane surface via coating with polymerizable bicontinuous microemulsion (PBM) materials. The PBM coating was polymerized within 1 min using ultraviolet (UV) light exposure. It was detected on the PES membrane surface via attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy.

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Line tension of sessile droplets: Thermodynamic considerations.

Phys Rev E

November 2023

Institute of Applied Materials-Microstructure Modelling and Simulation, Karlsruhe Institute of Technology (KIT), Strasse am Forum 7, Karlsruhe 76131, Germany.

We deduce a thermodynamically consistent diffuse interface model to study the line tension phenomenon of sessile droplets. By extending the standard Cahn-Hilliard model via modifying the free energy functional due to the spatial reflection asymmetry at the substrate, we provide an alternative interpretation for the wall energy. In particular, we find the connection of the line tension effect with the droplet-matrix-substrate triple interactions.

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Effect of wall free energy formulation on the wetting phenomenon: Conservative Allen-Cahn model.

J Chem Phys

October 2023

Institute for Applied Materials-Microstructure Modelling and Simulation (IAM-MMS), Karlsruhe Institute of Technology (KIT), Straße am Forum 7, Karlsruhe 76131, Germany.

Cahn introduced the concept of wall energy to describe the interaction between two immiscible fluids and a solid wall [J. W. Cahn, J.

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Identification of Lithium Compounds on Surfaces of Lithium Metal Anode with Machine-Learning-Assisted Analysis of ToF-SIMS Spectra.

ACS Appl Mater Interfaces

November 2023

Institute for Applied Materials - Microstructure Modelling and Simulation, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany.

Article Synopsis
  • Understanding contamination and surface treatment of lithium metal anodes is crucial for improving all-solid-state batteries.
  • Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a surface-sensitive method that analyzes LMA surfaces but can be complex to interpret manually.
  • This study utilizes machine learning, specifically logistic regression, to effectively identify lithium compounds from ToF-SIMS data, enhancing analysis and accuracy for both known and new samples.
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The use of saline water resources in agriculture is becoming a common practice in semi-arid and arid regions such as the Mediterranean. In the SmaCuMed project, the desalination of brackish groundwater (TDS = 2.8 g/L) for the irrigation of Argan trees in Essaouira, Morocco, to 2 g/L and 1 g/L (33% and 66% salt removal, respectively) using low-pressure reverse osmosis (LPRO) ( < 6 bar) and membrane capacitive deionization (MCDI) was tested at pilot scale.

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In view of the tremendous emissions of toxic gases and particulate matter (PM) by low-power firewood-fueled fireplaces, there is an urgent need for effective measures to lower emissions to keep this renewable and economical source for private home heating available in the future. For this purpose, an advanced combustion air control system was developed and tested on a commercial fireplace (HKD7, Bunner GmbH, Eggenfelden, Germany), complemented with a commercial oxidation catalyst (EmTechEngineering GmbH, Leipzig, Germany) placed in the post-combustion zone. Combustion air stream control of the wood-log charge combustion was realized by five different control algorithms to describe all situations of combustion properly.

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Sono-electrolysis performance based on indirect continuous sonication and membraneless alkaline electrolysis: Experiment, modelling and analysis.

Ultrason Sonochem

June 2023

National Higher School of Technology and Engineering, Department of Process Engineering, 23005 Annaba, Algeria; Center of Applied Research, Karlsruhe University of Applied Sciences, Moltkestr, 30, 76133 Karlsruhe, Germany.

In the present study, experiments of membraneless alkaline sono-electrolysis are combined to a mathematical model describing the performance of a sono-electrolyzer based on the electrochemical resistances and overpotentials (activation, Ohmic and concentration) and the oscillation of the acoustic cavitation bubble, and its related sono-physical and sonochemical effects, as a single unit and within population. The study aims to elucidate the mechanism of action of acoustic cavitation when coupled to alkaline electrolysis, using a membraneless H-cell configuration and indirect continuous sonication (40 kHz, 60 W). The calorimetric characterization constituted the bridge between experimental results and the numerical and simulation approach, while the quantification of the rate of produced hydrogen both experimentally and numerically highlighted the absence of the contribution of sonochemistry, and explained the role of ultrasounds by the action of shockwaves and microjets.

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Application of a Robust Thermoelectric Gas Sensor in Firewood Combustion Exhausts.

Sensors (Basel)

March 2023

Department of Functional Materials, Zentrum für Energietechnik (ZET), University of Bayreuth, D-95440 Bayreuth, Germany.

The quality of wood combustion processes can be effectively improved by achieving the automated control of the combustion air feed. For this purpose, continuous flue gas analysis using in situ sensors is essential. Besides the successfully introduced monitoring of the combustion temperature and the residual oxygen concentration, in this study, in addition, a planar gas sensor is suggested that utilizes the thermoelectric principle to measure the exothermic heat generated by the oxidation of unburnt reducing exhaust gas components such as carbon monoxide (CO) and hydrocarbons (CH).

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