Structure evolution in tribological interfaces studied by multilayer model alloys
Structure evolution in tribological interfaces studied by multilayer model alloys

Author: Cihan, Ebru

Publisher: KIT Scientific Publishing

Published: 2020-10-21

Total Pages: 194

ISBN-13: 3731509997

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Recent studies of deformation mechanisms of metals and alloys pioneer the better investigation of the friction and wear behavior of materials with well-defined initial microstructures. Within this scope, in this work, the effect of sub-surface deformations on the resulting friction and wear behavior has been searched by means of a systematic experimental study on Au-Ni metallic multilayer model alloy system.

Multiscale Modeling of Curing and Crack Propagation in Fiber-Reinforced Thermosets
Multiscale Modeling of Curing and Crack Propagation in Fiber-Reinforced Thermosets

Author: Schöller, Lukas

Publisher: KIT Scientific Publishing

Published: 2024-03-15

Total Pages: 230

ISBN-13: 3731513404

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During the production of fiber-reinforced thermosets, the resin material undergoes a reaction that can lead to damage. A two-stage polymerization reaction is modeled using molecular dynamics and evaluations of the system including a fiber surface are performed. In addition, a phase-field model for crack propagation in heterogeneous systems is derived. This model is able to predict crack growth where established models fail. Finally, the model is used to predict crack formation during curing.

Dynamic Model-based Analysis of Oxygen Reduction Reaction in Gas Diffusion Electrodes
Dynamic Model-based Analysis of Oxygen Reduction Reaction in Gas Diffusion Electrodes

Author: Röhe, Maximilian

Publisher: KIT Scientific Publishing

Published: 2024-01-09

Total Pages: 178

ISBN-13: 3731512343

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In this work, the first simulation model of oxygen depolarized cathodes (ODC), which are silver catalyst-based gas diffusion electrodes, is presented that considers the phase equilibrium of the gas-liquid interface and structure-related inhomogeneities in electrolyte distribution. By means of the model it has been identified that mass transport of water and ions in the liquid phase is a crucial factor for electrode performance and how it is influenced by the electrode structure.

Modeling transport properties and electrochemical performance of hierarchically structured lithium-ion battery cathodes using resistor networks and mathematical half-cell models
Modeling transport properties and electrochemical performance of hierarchically structured lithium-ion battery cathodes using resistor networks and mathematical half-cell models

Author: Birkholz, Oleg

Publisher: KIT Scientific Publishing

Published: 2022-10-05

Total Pages: 246

ISBN-13: 373151172X

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Hierarchically structured active materials in electrodes of lithium-ion cells are promising candidates for increasing gravimetric energy density and improving rate capability of the system. To investigate the influence of cathode structures on the performance of the whole cell, efficient tools for calculating effective transport properties of granular systems are developed and their influence on the electrochemical performance is investigated in specially adapted cell models.

Phase-field Modeling of Phase Changes and Mechanical Stresses in Electrode Particles of Secondary Batteries
Phase-field Modeling of Phase Changes and Mechanical Stresses in Electrode Particles of Secondary Batteries

Author: Zhang, Tao

Publisher: KIT Scientific Publishing

Published: 2021-09-27

Total Pages: 224

ISBN-13: 3731510022

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Most storage materials exhibit phase changes, which cause stresses and, thus, lead to damage of the electrode particles. In this work, a phase-field model for the cathode material NaxFePO4 of Na-ion batteries is studied to understand phase changes and stress evolution. Furthermore, we study the particle size and SOC dependent miscibility gap of the nanoscale insertion materials. Finally, we introduce the nonlocal species concentration theory, and show how the nonlocality influences the results.

Application of Data Mining and Machine Learning Methods to Industrial Heat Treatment Processes for Hardness Prediction
Application of Data Mining and Machine Learning Methods to Industrial Heat Treatment Processes for Hardness Prediction

Author: Lingelbach, Yannick

Publisher: KIT Scientific Publishing

Published: 2024-07-24

Total Pages: 278

ISBN-13: 3731513528

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This work presents a data mining framework applied to industrial heattreatment (bainitization and case hardening) aiming to optimize processes and reduce costs. The framework analyses factors such as material, production line, and quality assessment for preprocessing, feature extraction, and drift corrections. Machine learning is employed to devise robust prediction strategies for hardness. Its implementation in an industry pilot demonstrates the economic benefits of the framework. - This work presents a data mining framework applied to industrial heattreatment (bainitization and case hardening) aiming to optimize processes and reduce costs. The framework analyses factors such as material, production line, and quality assessment for preprocessing, feature extraction, and drift corrections. Machine learning is employed to devise robust prediction strategies for hardness. Its implementation in an industry pilot demonstrates the economic benefits of the framework.

On the Electro-Chemo-Mechanical Coupling in Solid State Batteries and its Impact on Morphological Interface Stability
On the Electro-Chemo-Mechanical Coupling in Solid State Batteries and its Impact on Morphological Interface Stability

Author: Ganser, Markus

Publisher: KIT Scientific Publishing

Published: 2021-03-09

Total Pages: 272

ISBN-13: 3731510472

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Solid state batteries with a lithium metal electrode are considered the next generation of high energy battery technology. Unfortunately, lithium metal is prone to harmful protrusion or dendrite growth which causes dangerous cell failure. Within this work the problem of protrusion growth is tackled by deriving a novel electro-chemo-mechanical theory tailored for binary solid state batteries which is then used to discuss the impact of mechanics on interface stability by numerical studies.

Consequences of hydroxyl generation by the silica/water reaction - Part II: Global and local Swelling - Part III: Damage and Young's Modulus
Consequences of hydroxyl generation by the silica/water reaction - Part II: Global and local Swelling - Part III: Damage and Young's Modulus

Author: Fett, Theo

Publisher: KIT Scientific Publishing

Published: 2022-07-11

Total Pages: 226

ISBN-13: 3731511592

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Water diffusing into silica surfaces gives rise for several effects on diffusion behaviour and mechanical properties. In a preceding booklet, we focused on diffusion and fiber strengths and deformations which were obtained by water soaking under external loading. In the present booklet we deal with results and interpretations of strength increase in the absence of applied stresses.

Consequences of hydroxyl generation by the silica/water reaction - Part I: Diffusion and Swelling
Consequences of hydroxyl generation by the silica/water reaction - Part I: Diffusion and Swelling

Author: Fett, Theo

Publisher: KIT Scientific Publishing

Published: 2022-07-11

Total Pages: 226

ISBN-13: 3731511487

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Water diffusing into silica surfaces gives rise for several effectson diffusion behaviour and mechanical properties. Water added to silica glass increases its specific volume so that the silica expands near the surface. Mechanical boundary conditions give rise for compressive “swelling stresses”. This fact provides a tool for the interpretation of many experimental observations from literature.

Development of NbN based Kinetic Inductance Detectors on sapphire and diamond substrates for fusion plasma polarimetric diagnostics
Development of NbN based Kinetic Inductance Detectors on sapphire and diamond substrates for fusion plasma polarimetric diagnostics

Author: Mazzocchi, Francesco

Publisher: KIT Scientific Publishing

Published: 2022-07-01

Total Pages: 212

ISBN-13: 3731511819

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This work aimed at designing, studying and producing the first prototypes of KIDs tailored for fusion plasma polarimetric diagnostics. Diamond was considered for the first time as substrate material for low-temperature superconducting detectors given its unmatched optical, radiation hardness and thermal qualities, properties necessary for working environments potentially saturated with radiation. This work represents a first step toward the optimization and final application of this technology.