In this study, the influence of production-related gaps on the shear tension strength and fatigue performance was investigated for resistance spot welded TRIP steel HCT690, Furthermore, the local ...strain distribution in shear tension test was calculated by the digital image correlation technique (DIG), The static shear tension strength was found to be almost independent of gaps up to 3 mm, The maximum local strain in the spot weld region however decreases depending on which sample side (deformed or undeformed) is considered, In addition, it has been ascertained that gaps of 3 mm lead to a significant drop in fatigue life compared to gap-free shear tension samples, This fact could be attributed to decreased stiffness, higher transverse vibration and higher rotation (0) between the sheets as well as increased local stress calculated by 2-dimensional FE simulation.
Animal models have been proven to be a crucial tool for investigating the physiological mechanisms underlying bariatric surgery in general and individual techniques in particular. By using a ...translational approach, most of these studies have been performed in rodents and have helped to understand how bariatric surgery may or may not work. However, data from studies using animal models should always be critically evaluated for their transferability to the human physiology. It is, therefore, the aim of this review to summarize both advantages and limitations of data generated by animal based experiments designed to investigate and understand the physiological mechanisms at the root of bariatric surgery.
Deep learning models have shown remarkable performances in egocentric video-based action recognition (EAR), but rely heavily on a large quantity of training data. In specific applications with only ...limited data available, eye movement data may provide additional valuable sensory information to achieve accurate classification performances. However, little is known about the effectiveness of gaze data as a modality for egocentric action recognition. We, therefore, propose the new Peripheral Vision-Based HMM (PVHMM) classification framework, which utilizes context-rich and object-related gaze features for the detection of human action sequences. Gaze information is quantified using two features, the object-of-interest hit and the object–gaze distance, and human action recognition is achieved by employing a hidden Markov model. The classification performance of the framework is tested and validated on a safety-critical medical device handling task sequence involving seven distinct action classes, using 43 mobile eye tracking recordings. The robustness of the approach is evaluated using the addition of Gaussian noise. Finally, the results are then compared to the performance of a VGG-16 model. The gaze-enhanced PVHMM achieves high classification performances in the investigated medical procedure task, surpassing the purely image-based classification model. Consequently, this gaze-enhanced EAR approach shows the potential for the implementation in action sequence-dependent real-world applications, such as surgical training, performance assessment, or medical procedural tasks.
Self-healing polymer coatings are a type of smart material aimed for advanced corrosion protection of metals. This paper presents the synthesis and characterization of two new UV-cure self-healing ...coatings based on acrylated polycaprolactone polyurethanes. On a macroscopic scale, the cured films all show outstanding mechanical properties, combining relatively high Young’s modulus of up to 270 MPa with a strain at break above 350%. After thermal activation the strained films recover up to 97% of their original length. Optical and electron microscopy reveals the self-healing properties of these coatings on hot dip galvanized steel with scratches and microindentations. The temperature-induced closing of such defects restores the corrosion protection and barrier properties of the coating as shown by electrochemical impedance spectroscopy and scanning vibrating electrode technique. Therefore, such coatings are a complementary option for encapsulation-based autonomous corrosion protection systems.
The Zinc level in many 6000 Al alloys (Al-Mg-Si-type) was set to a maximum of 0.03 wt% as common industrial practice. Concentrations above 0.03 wt% can modify the alkaline etching mechanism causing ...the surface to go from a desired smooth look associated with a grain boundary attack (GBA), into an undesired speckled appearance due to preferential grain etching (PGE), visible after anodizing. This significantly limits the ambition of reducing the carbon footprint of Aluminum by increasing the amount of recycled material in the production process. Because Cu has been reported to counteract this negative effect of Zn, the present study is dedicated to contribute to the understanding of this interaction and is focused on Zn and Cu in peak aged AlMgSi alloys. The chemical composition of the various precipitates formed in two Al6063 alloys was studied by means of TEM and EDX, whereby Zn was found in the Q phase (AlMgSiCu) grain boundary precipitates. Two alloys, with different content of Cu and Zn were studied. The Zn/Cu ratio in the bulk was similar for both alloys, but the level of Zn in the Cu containing Q particles in the grain boundaries was different. The increased Zn concentration in Q phase precipitates is believed to decrease the potential of the precipitates with respect to the surrounding matrix. Thus, the Cu/Zn ratio in these alloys is extremely important as it defines the potential differences that in turn cause either GBA or PGE.
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•Zinc accumulates in Q phase (AlMgSiCu) grain boundary precipitates (GBPs).•Increasing the Zn level in the alloy, increases the Zn content in the GBPs.•The interaction of Zn and Cu has and effect on the alkaline etching behavior of Al-Mg-Si alloys.
Im Mittelpunkt des vorliegenden Bandes steht die Untersuchung des Selbstverständnisses der praktischen Wissenschaften, wie es sich im 13. und 14. Jahrhundert im Umkreis der Höheren Fakultäten der ...Universität sowie insbesondere innerhalb der Philosophie artikuliert. Die Frage nach der Wissenschaftsfähigkeit des überlieferten juristischen und medizinischen Wissens sowie jene nach dem wissenschaftlichen Anspruch der Praktischen Philosophie, insbesondere der philosophischen Ethik, und der Theologie, verstanden als einer "scientia practica", beschreiben die Herausforderung, mit der sich die hier behandelten Autoren und Texte des Mittelalters beschäftigen. Insbesondere werden in den in diesem Band versammelten Einzeluntersuchungen die Beiträge von Albert dem Großen, Thomas von Aquin, Johannes Duns Scotus und Wilhelm von Ockham zur Frage einer philosophischen Begründung des Status des menschlichen Handlungswissens und der praktischen Wissenschaften gewürdigt.
•An in-depth study of the electrochemical behaviour of plasma coatings for the protection of PCBs was carried out.•Combination of surface-averaged and local techniques provides a better insight into ...the behaviour of plasma coatings.•The protection performance level of the different types of plasma coatings was defined based on the obtained results.•Improvement of the protection behaviour using stacked plasma coatings was observed.
Printed Circuit Boards (PCB) are the backbone of electronic devices and communication technology. The corrosion of copper tracks in PCBs is the main reliability issue in case of exposure to humidity. To overcome this, several surface finishing methods have been introduced in the industry such as plasma coatings. In this study, several electrochemical characterisation methods are explored on blank and plasma-coated PCBs to identify reliable measurement techniques and to get insight in the protective properties of the coatings on an overall macroscopic visual scale, a dedicated surface-average scale, as well as on a localised microscopic scale. The macroscopic visual corrosion behaviour was evaluated by standard salt-spray exposure tests. Odd Random Phase multisine Electrochemical Impedance Spectroscopy (ORP-EIS) provided insight into the average barrier properties of the coatings. Scanning Vibrating Electrode Technique (SVET) and Scanning Kelvin Probe Force Microscopy (SKPFM) were used to evaluate the samples’ reactivity on a local scale. Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) analysis was used as a complementary surface analysis method to characterise the coatings. Blank PCBs were studied as reference substrates, and their behaviour was compared to three plasma-coated PCB variants, based on fluorinated organic precursor chemistry. The salt-spray tests illustrated the protective behaviour of the coatings but did not allow to differentiate between the different coatings. With ORP-EIS, it was observed that the coatings act as a barrier against the electrolyte. This is confirmed on the local scale, where no activities were seen on the surface of the coated samples using SVET, except after 10 days of immersion when single layer plasma coatings showed higher activities. SKPFM revealed much higher surface potentials for the coated PCBs compared to the blank PCB allowing to differentiate between the various coated samples.
This paper investigates the impact of a ministry's budget size on the choice between auditing a (Niskanen)bureau and employing competitive bidding in the provision of a publicly funded good. The ...ministry's marginal expected payoff increases fastest with budget size for auctioning as opposed to auditing. However, the ministry is shown to switch from a purely public provision to a competitive provision as the budget size increases even if expected fixed costs favor the audit. The study contributes to the literature by extending the Niskanen framework and by endogenizing the institutional arrangements for the provision of public sector goods.
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