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From impact to action:An inverse dynamics approach for estimating total ankle forces in outdoor running using inertial sensors
No full textRunning is one of the most popular sports activities in the world and provides physical and mental health benefits. However, running is also associated with a high incidence of (overuse) injuries. Given its global popularity, monitoring runners and understanding the aetiology of injuries is essential for injury prevention. To understand the repetitive character of running, impact-related parameters such as peak tibial acceleration (PTA) are commonly used. However, these reflect only external impact forces and not total joint force, which also includes muscle contributions. Because tissue fatigue life is strongly influenced by active (muscle) forces, these may be more relevant than impact measures only. Incorporating active (muscle) forces is therefore important for a comprehensive understanding of running-related injuries, especially in an outdoor, sports-specific setting.Inverse dynamics is a method for estimating joint forces and moments, which typically requires gold standard measurement systems. However, these systems are impractical in outdoor settings. Inertial measurement units (IMUs) provide a feasible alternative due to their ease of use in real-world scenarios. The aim of this thesis is to advance motion analysis methods in sports-specific settings using IMUs, allowing a more comprehensive analysis of both impact and active (muscle) forces during outdoor running.Chapter 2 focuses on PTA and tibial impulse, by using a standardised IMU-based method to obtain impact-acceleration only. Chapter 3 demonstrates that a top-down inverse dynamics approach using IMUs can accurately estimate knee moments. Chapter 4 introduces a method to estimate anteroposterior CoP from a single tibial IMU, enabling accurate sagittal ankle moment and total ankle force estimation with only three IMUs. Chapter 5 combines these methods outdoors, showing increases in impact measures during fatigue while active forces remained stable, highlighting their distinct behaviours.This dissertation contributes to the growing interest in using IMUs in uncontrolled settings. These studies provide a foundation for research into running-related injuries, where the interaction between impact and active (muscle) forces at the ankle joint can be estimated and evaluated using a simple three-IMU setup in an outdoor environment
Chemisorption of H radical generated volatile Si hydrides on Ru films
No full textIn this work, we investigate how Ru thin film surfaces adsorb Si by exposure to H radicals (H*) in a vacuum system containing solid Si. H* effectively reduce the native oxide of Ru and etch Si, forming volatile SiHx. We demonstrate that Ru without native oxide catalyzes dissociation of SiH4 near room temperature (in the absence of H*) with a SiH4 sticking probability of ∼ 5·10−7 and an adsorption limit of ∼ 1 monolayer (ML), due to saturation of reactive Ru sites. In the presence of H*, gas phase reactions are supposed to convert SiH4 to SiHx* radicals. SiHx*, formed in this way, has a sticking probability of ≥ 0.5 and an adsorption limit of ∼ 2.6 ML on Ru. This adsorption limit exceeds the adsorption limit of 1 ML for catalytic SiH4 dissociation. Interaction of SiHx* and Ru leads to a thermodynamically favorable Si and Ru intermixing and formation of RuxSiy with a Si surface layer. Observations suggest that SiHx* species only chemisorb to Ru surface sites, making the adsorption self-limiting.</p
Multiscale Modeling of Heat Transfer in Graphene-Copper Nanocomposites
No full textThis study investigates the thermal properties of graphene-copper metal-matrix composites, resolving nanoscale structures through Non-Equilibrium Molecular Dynamics (NEMD) simulations and developing a continuum-upscaled model using homogenization. The continuum model is based on the NEMD findings and aims to predict the thermal properties of graphene-copper powders, which serve as feedstock material for Additive Manufacturing (AM).Recent advances in AM have created new opportunities for realizing composite materials and novel parts with unique structures and properties. Here, the combination of graphene, a highly conductive two-dimensional material with an in-plane conductivity in the range of [3000-5000] W/mK, with copper is studied for its mechanical and heat transfer properties. However, accurately predicting the thermal and mechanical characteristics of the resulting material is challenging as the nanoscale interactions between the constituent elements on atomistic scales need to be translated to macroscopic material properties.We have performed NEMD using LAMMPS to simulate the anisotropic thermal conductivity and interface resistance of graphene-copper nano-structures. Since research has shown that the thermal properties of interfaces are structure- and size-dependent, we have performed these simulations for various configurations. These are reference Representative Elementary Volumes (RVEs) on which upscaling should be based. We aim to establish a reliable mesoscale model based on nanoscale heat transport properties extracted from the RVEs of graphene-copper structures. Our poster presents findings from the heat transfer model, informed by nanoscale data, and features of the approach to a 3D reconstruction of the manufactured graphene-copper material
Unlocking Silver Expertise:Redefining Workforce Training Development in Purchasing for Industry 4.0
No full textThis study addresses the challenges of an ageing workforce in purchasing and supply management (PSM), driven by demographic shifts like rising retirement ages and declining birth rates. It focuses on “Silver Workers” (employees aged 50+), highlighting their value and the need for tailored training to meet the demands of Industry 4.0 using survey data from PSM professionals. The research contributes by deepening the understanding of the ‘Silver Workers’ concept, evaluating training methods tailored to their needs, and assessing the effectiveness of professional training programs. These insights support workforce adaptability, inclusivity, and innovation, ensuring organisations can fully leverage the expertise of a multigenerational workforce while addressing skill shortages and technological challenges
E-auction research in the era of industry 4.0 and AI:A systematic review and research agenda
No full textIn Purchasing and Supply Management (PSM), electronic auctions (e-auctions) are vital tools for cost savings, efficiency, and transforming supplier-buyer relationships. This paper offers a comprehensive literature review on e-auctions in SCM, highlighting future research calls over the past two decades and the potential impacts of Industry 4.0, AI, and Blockchain. By reviewing historical and contemporary e-auctions research on antecedents, consequences, and design recommendations, this study identifies existing knowledge and research gaps. It underscores the transformative potential of e-auctions, particularly with Industry 4.0, AI, and blockchain, and complements a recent review of e-auctions in marketing
From drought to aridification: land‐cover fingerprints of a drying Chile
No full textChile has endured a decade‐long “mega‐drought,” yet it remains unclear whether this represents a temporary climate anomaly or the onset of long‐term aridification. While droughts are typically temporary events, persistent or recurrent droughts can indicate a transition toward aridification, that is, a gradual shift to drier conditions. We assessed how temporal changes in water supply and demand at multiple time scales affect vegetation productivity and land cover changes in continental Chile to diagnose the region's climate trajectory from drought to aridification. Since 2000, much of the region has seen a continuous decrease in water supply alongside a rise in atmospheric water demand. Further, in water‐limited ecoregions, evapotranspiration, likely reflecting reduced transpiration or vegetation cover, has declined over time, with this trend intensifying over longer time scales. A long‐term decline in water availability and shifting demand have led to declining vegetation productivity, especially in the Chilean Matorral and the Patagonia Steppe ecoregions. We discovered a link between these declines and drought indices related to soil moisture and actual evapotranspiration at time scales of up to 12 months. Further, our results indicate that the trends in drought indices account for up to 78% of shrubland and 40% of forest area changes across all ecoregions. The most important variable explaining cropland changes is the burned area. Our findings suggest that Chile is undergoing a transition from episodic drought to aridification, underscoring the need for adaptation strategies aligned with this emerging baseline
Real-time bundle adjustment for ultra-high-resolution UAV imagery using adaptive patch-based feature tracking
No full textReal-time processing of UAV imagery is crucial for applications requiring urgent geospatial information, such as disaster response, where rapid decision-making and accurate spatial data are essential. However, processing high-resolution imagery in real time presents significant challenges due to the computational demands of feature extraction, matching, and bundle adjustment (BA). Conventional BA methods either downsample images, sacrificing important details, or require extensive processing time, making them unsuitable for time-critical missions. To overcome these limitations, we propose a novel real-time BA framework that operates directly on fullresolution UAV imagery without downsampling. Our lightweight, onboard-compatible approach divides each image into user-defined patches (e.g., NxN grids, default 150×150 pixels) and dynamically tracks them across frames using UAV GNSS/IMU data and a coarse, globally available digital surface model (DSM). This ensures spatial consistency for robust feature extraction and matching between patches. Overlapping relationships between images are determined in real time using UAV navigation system, enabling the rapid selection of relevant neighbouring images for localized BA. By limiting optimization to a sliding cluster of overlapping images, including those from adjacent flight strips, the method achieves real-time performance while preserving the accuracy of global BA. The proposed algorithm is designed for seamless integration into the DLR Modular Aerial Camera System (MACS), supporting largearea mapping in real time for disaster response, infrastructure monitoring, and coastal protection. Validation on MACS datasets with 50MP images demonstrates that the method maintains precise camera orientations and high-fidelity mapping across multiple strips, running full bundle adjustment in under 2 seconds without GPU acceleration
Commissioning-based framework to enhance asset life cycles in manufacturing environments
No full textProduction environments and their constituent assets often deviate from their original design intent because of design assumptions, variability in materials and processes, and external stressors. Furthermore, assets are not always used as intended, requiring mechanisms to validate their performance over time. Traditionally, commissioning ensures compliance with client requirements before operational deployment but is typically treated as a one-time event. This study extends the concept of commissioning to support ongoing validation throughout the entire asset lifecycle using a commissioning-based framework. This framework enables the assessment of current configurations and exploration of future scenarios, allowing for context-aware (re)commissioning by balancing a priori and a posteriori activities. Commissioning thereby shifts to an integral and iterative process that facilitates alignment between evolving requirements and actual system behaviour, supporting better-informed decision-making