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In a secure biometric verification system, users authenticate themselves by submitting their encrypted biometric data to the application server. Such systems must be able to defend against 1) malicious clients that try to gain unauthorized access to the system; and 2) malicious servers that aim to identify the users’ plaintext biometric data. To this end, our work introduces an efficient biometric verification protocol that is provably secure against both a malicious client and a malicious server. We formally prove the security of our scheme in the random oracle model and also present results from a proof-of-concept implementation. Our results demonstrate that the protocol is very efficient, incurring just 880 ms of computational overhead and 99 KB of communication cost.

Study Region: This study investigates the on- and offshore fresh to saline groundwater distribution as well as the submarine groundwater discharge within a coastal karstic aquifer system in Antalya (Türkiye). Study Focus: Groundwater acts as a critical link between on- and offshore environments, connecting freshwater systems to the saline oceans. With an increasing population along coastlines, understanding coastal groundwater interactions is essential. In this study we utilize on- and offshore hydrogeophysical techniques to image variations in subsurface porewater salinities. Offshore continuous resistivity profiling and hydroacoustic measurements are complemented by land based electromagnetic measurements. New hydrological insights for the region: Our findings show how groundwater discharges into the sea through coastal and submarine freshwater springs while simultaneously facing the risk of saltwater intrusions nearby. Diffuse groundwater flow dominates along the main beach area of Antalya, while channelized flow occurs primarily along the cliff coastline where submarine springs occur. The springs create distinct salinity anomalies in the water column and remove the sediment cover from the carbonate aquifer, exposing hard rock on the seafloor and creating different habitats. The multi-method geophysical approach provides a detailed picture of freshwater-saltwater interactions and highlights regions of varying groundwater discharge into the sea. Our findings contribute valuable insights for water management strategies in Antalya, with implications for safeguarding freshwater resources and mitigating the risk of saltwater intrusions.

This study presents a comprehensive ultrasound image dataset for Non-Alcoholic Fatty Liver Disease (NAFLD), addressing the critical need for standardized resources in AI-assisted diagnosis. The dataset comprises 10,352 high-resolution ultrasound images from 384 patients collected at King Saud University Medical City and National Guard Health Affairs in Saudi Arabia. Each image is meticulously annotated with NAFLD Activity Score (NAS) fibrosis staging and steatosis grading based on corresponding liver biopsy results. Unlike other datasets that rely on bounding boxes, we opted for full-image labelling based on biopsy findings, which link to histopathological results, ensuring more precise representation of liver conditions. Rigorous pre-processing ensures high-quality image preservation, including expert radiologist assessment, DICOM to PNG conversion, and standardization to 768 × 1024 pixels. This resource supports various computer vision tasks, enabling the development of AI algorithms for accurate NAFLD diagnosis and staging. A large, diverse, and well-annotated dataset like ours is essential for enhancing model performance and generalization, providing a valuable resource for researchers to develop robust AI models in medical imaging.

Abstract Natural seafloor depressions, known as pockmarks, are common subaqueous geomorphological features found from the deep ocean trenches to shallow lakes. Pockmarks can form rapidly or over millions of years and have a large variety of shapes created and maintained by a large variety of mechanisms. In the sandy sediments of the southeastern North Sea, abundant shallow pockmarks are ubiquitous and occur at shallow water depths (

This research is related to the structural performance of a shell-type system made of hollow glass units (HGU) that utilizes glass as the primary structural material. The efficient structural function of the proposed shell-type system is designed using Polyhedral Graphic Statics to achieve a system geometry that maximizes in-plane compression and limits the presence of tension. The large-scale shell structure is constructed using a modular assembly of individual hollow glass units. To date, the research team has completed studies on individual HGU strength and stiffness, and the performance of the interface material necessary to transmit the high in-plane compression forces between neighboring HGUs. As well, the feasibility of the proposed modular system has also been demonstrated through the successful assembly and disassembly of a 3 m span prototype pedestrian bridge known as Tortuca. Tortuca is comprised of 13 individual interlocking HGUs assembled into a compression-dominant form supported on steel abutments. In the current research study, the physical performance of Tortuca is experimentally investigated under controlled laboratory testing and using an extensive assortment of displacement and strain sensors. Significant findings related to experimental testing of Tortuca will be reported.

Thermally toughened safety glass must meet safety requirements in the building industry. Here, destructive tests are defined in the product standards, which must be carried out on small, standardized format (360 mm x 1100 mm) glass elements to determine the fracture pattern and bending strength. This is costly and not in the interests of sustainability. As part of the quality control of optical anisotropy effects in tempered glass, isochromatic scans that can provide information on the edge stress are acquired. The evaluation of the isochromatics and retardations at the edge with deduction of the edge stress and transfer to bending strength and fracture pattern could provide essential findings for assuring the safety requirements of tempered glass. In this experimental investigation, the surface and edge stress were measured on standardized format thermally toughened safety glass, with different edge processing and glass thicknesses from three different suppliers. Afterwards, the fracture pattern is controlled, or the bending strength is analyzed in a destructive four-point bending test. Conclusively, the results from the photoelastic and destructive tests are compared to determine whether the photoelastic measurement methods used to measure surface and edge stress can be employed as quality control.

Introduction. Biometric verification for controlling access to digital devices has become ubiquitous for its ease-of-use but often relies on notoriously data-hungry supervised machine learning. Additionally, biometric data is privacy-sensitive, and a comprehensive review from a data set perspective is missing. This survey provides detailed insights into data acquisition and Additionally, it offers a thorough discussion of related applications and state-of-the-art performance. Methodology. We present a comprehensive and structured review of multimodal face data sets containing RGB color and other channels such as infrared or depth. This follows a trend to use such additional modalities to improve the robustness and reliability of biometric verification systems. Starting with around 1,000 papers, retrieved based on search queries and forward-/backward-referencing, we selected 200 papers in this survey following our inclusion and exclusion criteria. We discuss around 150 multimodal data sets. Principal Findings. Multimodal data opens the path to many additional applications, such as 3D face reconstruction (e.g., to create avatars for VR/AR environments), detection, registration, alignment, and recognition systems, emotion detection, anti-spoofing, etc. Our findings show that multimodal data can boost performance and robustness in many applications. However, consistent concerns include cross-domain generalization problems due to biases in ethnicity, age, and gender, and class imbalances that may lead to mispredictions or underrepresentation of minorities. We believe that the latter point deserves future research, not only to represent minorities accurately but also to tackle societal and infrastructural biases and to ensure that work based on such data sets remains fair and equitable.

Shallow, semi-enclosed coastal systems are particularly prone to eutrophication. Depending on local site conditions and historical nutrient legacies, sea-based measures might be necessary in addition to land-based nutrient removal. In this study, C:N:P ratios were combined with open-source bathymetric information and linked with the prevailing geomorphological and sedimentological regimes to gain insights into nutrient hotspots and understand their sources and fate in coastal waters. Land-based sediment samples were taken behind outlets at three sites in Eckernförde Bay (Baltic Sea), and complemented with ship-based sampling at locations approximately 8 m and 12 m water depth. The total carbon, nitrogen and phosphorus concentrations in surface sediments increased at deeper sites. This suggests that an increased downslope particle transport and deposition regime, based on local geomorphology, might influence nutrient hotspots to a larger extent than proximity to sources (e.g., outlets). Overall, the recorded C:N ratios (mean = 28.12) were closer to the ratio of terrestrial plants than those of marine phytoplankton, indicating allochthonous sources of organic matter.

Abstract Seabed pockmarks are among the most prominent morphologic structures in the oceans. They are usually interpreted as surface manifestation of hydrocarbon fluids venting from sediments. Here we suggest an alternative hypothesis of pockmark formation based on latest multibeam echosounder data with a centimeter resolution. In the North Sea, >40,000 enigmatically shaped shallow depressions or ‘pits’ with a mean depth of 0.11 m were documented, that do not resemble known pockmark morphologies. Combining the new echosounder data with information from behavioral biology, physical oceanography, satellite remote sensing and habitat mapping, we conclude that harbor porpoises excavate sediments during benthic foraging. By grubbing the seabed, they cause sandeels to escape from the sediment and initiate the formation of seafloor pits. Time-lapse data reveals that the initially feeding pits serve as nuclei for scouring and eventually merge into larger scour-pits. With the immense number of vertebrates in the ocean, such megafauna-driven macro-bioturbation reshapes the seafloor, modulates sediment transport, and ultimately impacts associated ecosystems on a global scale.

Background: Hepatocyte ballooning (HB) is a significant histological characteristic linked to the advancement of non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). Although clinicians now consider liver biopsy the most reliable method for identifying HB, its invasive nature and related dangers highlight the need for the development of non-invasive diagnostic options. Objective: This study aims to develop a novel methodology that combines deep learning and machine learning techniques to accurately identify and measure hepatobiliary abnormalities in liver ultrasound images. Methods: The research team expanded the dataset, consisting of ultrasound images, and used it for training deep convolutional neural networks (CNNs) such as InceptionV3, ResNet50, DenseNet121, and EfficientNetB0. A hybrid approach, combining InceptionV3 for feature extraction with a Random Forest classifier, emerged as the most accurate and stable method. An approach of dual dichotomy classification was used to categorize images into two stages: healthy vs. sick, and then mild versus severe ballooning.. Features obtained from CNNs were integrated with conventional machine learning classifiers like Random Forest and Support Vector Machines (SVM). Results: The hybrid approach achieved an accuracy of 97.40%, an area under the curve (AUC) of 0.99, and a sensitivity of 99% for the ‘Many’ class during the third phase of evaluation. The dual dichotomy classification enhanced the sensitivity in identifying severe instances of HB. The cross-validation process confirmed the strength and reliability of the suggested models. Conclusions: These results indicate that this combination method can decrease the need for invasive liver biopsies by providing a non-invasive and precise alternative for early identification and monitoring of NAFLD and NASH. Subsequent research will prioritize the validation of these models using larger datasets from multiple centers to evaluate their generalizability and incorporation into clinical practice.

Abstract The prophylactic action of non-steroidal anti-inflammatory drugs (NSAIDs) in heterotopic ossification (HO) was first described following analgesic therapy with indomethacin. Following that evidence, several compounds have been successfully used for prophylaxes of HO. Ibuprofen has been also proposed for the prevention of HO following THA. The present study compared the administration of ibuprofen for three weeks versus indomethacin as prophylaxis for HO following primary THA. In all THA procedures, pre- and post-operative protocols were conducted in a highly standardized fashion. The type of HO prophylaxis (indomethacin 100 mg/daily or ibuprofen 100 mg/daily) was chosen according to a chronological criterion: from 2017 to 2019 indomethacin was used, whereas from 2019 to 2022 ibuprofen was administered. In case of allergy or intolerance to NSAIDs, no prophylaxis was performed, and patients were included as a control group. All patients who underwent an anteroposterior radiography of the pelvis at a minimum of 12 months following THA were considered for inclusion. On admission, the age and sex of the patients were recorded. Moreover, the causes of osteoarthritis and the date of surgery were recorded. The grade of HO was assigned by a blinded assessor who was not involved in the clinical management of the patients. The modified Brooker Staging System was used to rate the efficacy of the interventions. Data from 1248 patients were collected. 62% (767 of 1248 patients) were women. The mean age was 67.0 ± 2.9 years. The mean follow-up was 21.1 ± 10.8 months. In the ibuprofen group, 73% of patients evidenced Brooker 0, 17% Brooker I, and 10% Brooker II. In the indomethacin group, 77% of patients evidenced Brooker 0, 16% Brooker I, 6% Brooker II. No patient in the ibuprofen and indomethacin group developed Brooker III or IV. In the control group, 64% of patients evidenced Brooker 0, 21% Brooker I, 3% Brooker II, and 12% Brooker III. No patient in the control group developed Brooker IV HO. Concluding, three weeks of administration of ibuprofen demonstrated similar efficacy to indomethacin in preventing HO following primary THA. The prophylaxis with ibuprofen or indomethacin was more effective in preventing HO compared to a control group who did not receive any pharmacological prophylaxis.

BackgroundResearch gaps refer to unanswered questions in the existing body of knowledge, either due to a lack of studies or inconclusive results. Research gaps are essential starting points and motivation in scientific research. Traditional methods for identifying research gaps, such as literature reviews and expert opinions, can be time consuming, labor intensive, and prone to bias. They may also fall short when dealing with rapidly evolving or time-sensitive subjects. Thus, innovative scalable approaches are needed to identify research gaps, systematically assess the literature, and prioritize areas for further study in the topic of interest. ObjectiveIn this paper, we propose a machine learning–based approach for identifying research gaps through the analysis of scientific literature. We used the COVID-19 pandemic as a case study. MethodsWe conducted an analysis to identify research gaps in COVID-19 literature using the COVID-19 Open Research (CORD-19) data set, which comprises 1,121,433 papers related to the COVID-19 pandemic. Our approach is based on the BERTopic topic modeling technique, which leverages transformers and class-based term frequency-inverse document frequency to create dense clusters allowing for easily interpretable topics. Our BERTopic-based approach involves 3 stages: embedding documents, clustering documents (dimension reduction and clustering), and representing topics (generating candidates and maximizing candidate relevance). ResultsAfter applying the study selection criteria, we included 33,206 abstracts in the analysis of this study. The final list of research gaps identified 21 different areas, which were grouped into 6 principal topics. These topics were: “virus of COVID-19,” “risk factors of COVID-19,” “prevention of COVID-19,” “treatment of COVID-19,” “health care delivery during COVID-19,” “and impact of COVID-19.” The most prominent topic, observed in over half of the analyzed studies, was “the impact of COVID-19.” ConclusionsThe proposed machine learning–based approach has the potential to identify research gaps in scientific literature. This study is not intended to replace individual literature research within a selected topic. Instead, it can serve as a guide to formulate precise literature search queries in specific areas associated with research questions that previous publications have earmarked for future exploration. Future research should leverage an up-to-date list of studies that are retrieved from the most common databases in the target area. When feasible, full texts or, at minimum, discussion sections should be analyzed rather than limiting their analysis to abstracts. Furthermore, future studies could evaluate more efficient modeling algorithms, especially those combining topic modeling with statistical uncertainty quantification, such as conformal prediction.

Abstract Between 2 and 20% of patients who undergo total knee arthroplasty (TKA) report restricted motion and anterior knee pain. Non-optimal alignment of the implant components is a common cause of such complaints. Robotic-assisted TKA has been advocated to improve the accuracy of component positioning to match patients’ anatomy and biomechanics. However, the advantages of robotic surgery over conventional freehand TKA are still unclear. The present study is a protocol for a single-blind clinical trial in which patients will be randomly allocated to undergo either robotic-assisted TKA or conventional freehand TKA. A restricted kinematic alignment with medial para-stellar approach shall be made in all patients. The present study follows the SPIRIT guidelines. The primary outcome of interest is to compare robotic TKA versus traditional freehand TKA in terms of patient-reported outcome measures (PROMs), length of hospitalisation, blood values, blood transfusion units, and range of motion. The second outcome of interest is to evaluate the accuracy of component positioning of robotic-assisted TKA compared to the conventional freehand TKA. Level of evidence Level I, randomised controlled trial. Registration German Registry of Clinical Trials (ID: DRKS00030614).

The “metaverse” has gained immense attention as the next internet frontier, holding significant economic implications, especially for the IT sector. To establish the groundwork for immersive metaverse spaces, our comprehensive scoping review uncovers the current techniques and technologies in metaverse development. This study investigates post-COVID-19 metaverse techniques, technologies, and applications, spanning from January 2020 to December 2022. Findings reveal potential metaverse applications across 11 industries, with education, manufacturing, healthcare, and real estate being notable. We identified 12 major technologies and four key development techniques that have gained prominence in the metaverse landscape. Notably, “Extended Reality (XR)”, “Artificial Intelligence (AI)”, and “Decentralized Technologies” were the three most frequently mentioned technologies, appearing in 73%, 40%, and 30% of the reviewed articles, respectively. Furthermore, “VR space convergence” and “fundamental technology” emerged as primary enablers in 73% and 43% of the selected articles, with “object connection” and “communication computing infrastructure” playing supportive roles. Integrating these technologies is vital for holistic metaverse development. Our report serves as a catalyst for discussions among stakeholders, promoting further research and the transformative potential of the metaverse. It highlights the need for advancing understanding and technological evolution in this emerging digital realm.

Public health surveillance systems play a crucial role in detecting and responding to disease outbreaks. Visualizations of surveillance data are important for decision-making, but little attention has been paid to the usability and interaction of such systems. In this paper, we developed a set of 10 heuristics to assess the visualization and usability of public health surveillance systems. The heuristics cover aspects of perception, cognition, and interaction. The perception deals with how the system looks in the first glance and whether it has pleasant effect on the user or otherwise. Cognition deals with the question of whether enough information is provided to use the system, while usability and interaction deal with whether the system is user-friendly in terms of the tools provided for interaction and use. We recruited a panel of experts to evaluate a set of systems using our heuristics. Results showed that there was variation in the scores of the experts' assessments, indicating the importance of multiple expert evaluations. Our heuristics provide a practical and comprehensive tool for assessing the visualization and usability of public health surveillance systems, which can lead to improved decision-making and ultimately better public health outcomes. The results suggest that the heuristic based evaluation through a panel of experts can provide meaningful results and insights into the usability aspects of public health systems. The results suggest that for some systems there can be agreement in terms of evaluation while for some other systems the experts’ opinions can vary based on the weightage and importance each expert gives to a particular aspect.

The concept of the “metaverse” has garnered significant attention recently, positioned as the “next frontier” of the internet. This emerging digital realm carries substantial economic and financial implications for both IT and non-IT industries. However, the integration and evolution of these virtual universes bring forth a multitude of intricate issues and quandaries that demand resolution. Within this research endeavor, our objective was to delve into and appraise the array of challenges, privacy concerns, and security issues that have come to light during the development of metaverse virtual environments in the wake of the COVID-19 pandemic. Through a meticulous review and analysis of literature spanning from January 2020 to December 2022, we have meticulously identified and scrutinized 29 distinct challenges, along with 12 policy, privacy, and security matters intertwined with the metaverse. Among the challenges we unearthed, the foremost were concerns pertaining to the costs associated with hardware and software, implementation complexities, digital disparities, and the ethical and moral quandaries surrounding socio-control, collectively cited by 43%, 40%, and 33% of the surveyed articles, respectively. Turning our focus to policy, privacy, and security issues, the top three concerns that emerged from our investigation encompassed the formulation of metaverse rules and principles, the encroachment of privacy threats within the metaverse, and the looming challenges concerning data management, all mentioned in 43%, 40%, and 33% of the examined literature. In summation, the development of virtual environments within the metaverse is a multifaceted and dynamically evolving domain, offering both opportunities and hurdles for researchers and practitioners alike. It is our aspiration that the insights, challenges, and recommendations articulated in this report will catalyze extensive dialogues among industry stakeholders, governmental bodies, and other interested parties concerning the metaverse's destiny and the world they aim to construct or bequeath to future generations.

Abstract Artificial intelligence (AI) has been successfully exploited in diagnosing many mental disorders. Numerous systematic reviews summarize the evidence on the accuracy of AI models in diagnosing different mental disorders. This umbrella review aims to synthesize results of previous systematic reviews on the performance of AI models in diagnosing mental disorders. To identify relevant systematic reviews, we searched 11 electronic databases, checked the reference list of the included reviews, and checked the reviews that cited the included reviews. Two reviewers independently selected the relevant reviews, extracted the data from them, and appraised their quality. We synthesized the extracted data using the narrative approach. We included 15 systematic reviews of 852 citations identified. The included reviews assessed the performance of AI models in diagnosing Alzheimer’s disease (n = 7), mild cognitive impairment (n = 6), schizophrenia (n = 3), bipolar disease (n = 2), autism spectrum disorder (n = 1), obsessive-compulsive disorder (n = 1), post-traumatic stress disorder (n = 1), and psychotic disorders (n = 1). The performance of the AI models in diagnosing these mental disorders ranged between 21% and 100%. AI technologies offer great promise in diagnosing mental health disorders. The reported performance metrics paint a vivid picture of a bright future for AI in this field. Healthcare professionals in the field should cautiously and consciously begin to explore the opportunities of AI-based tools for their daily routine. It would also be encouraging to see a greater number of meta-analyses and further systematic reviews on performance of AI models in diagnosing other common mental disorders such as depression and anxiety.

Abstract Seagrass meadows are one of the most important benthic habitats in the Baltic Sea. Nevertheless, spatially continuous mapping data of Zostera marina, the predominant seagrass species in the Baltic Sea, are lacking in the shallow coastal waters. Sentinel‐2 turned out to be valuable for mapping coastal benthic habitats in clear waters, whereas knowledge in turbid waters is rare. Here, we transfer a clear water mapping approach to turbid waters to assess how Sentinel‐2 can contribute to seagrass mapping in the Western Baltic Sea. Sentinel‐2 data were atmospherically corrected using ACOLITE and subsequently corrected for water column effects. To generate a data basis for training and validating random forest classification models, we developed an upscaling approach using video transect data and aerial imagery. We were able to map five coastal benthic habitats: bare sand (25 km²), sand dominated (16 km²), seagrass dominated (7 km²), dense seagrass (25 km²) and mixed substrates with red/ brown algae (3.5 km²) in a study area along the northern German coastline. Validation with independent data pointed out that water column correction does not significantly improve classification results compared to solely atmospherically corrected data (balanced overall accuracies ~0.92). Within optically shallow waters (0–4 m), per class and overall balanced accuracies (>0.82) differed marginally depending on the water depth. Overall balanced accuracy became worse (

The black coral Anthipatella wollastoni forms marine animal forests in the mesophotic zone. The spatial extent of black coral forests is not well known in many regions. Due to its protein and chitin skeleton, the coral is difficult to image using acoustic remote sensing techniques compared to corals with carbonate skeletons. Several manufacturers have recently introduced an additional data type to their multibeam echosounders, called “multi-detection,” which provides additional target detections per beam in addition to the primary bottom detection. In this study, we used a Norbit chirp multibeam echosounder in multi-detect mode to acquire up to three targets in each beam in an area of black coral below 45 m depth off the coast of Lanzarote (Canary Islands, Spain). Multi-detect allows features above and below the primary bottom detection to be identified without the need to store and process water-column data. Black coral can be detected by comparing “multi-detection” data with ground truthing by technical divers and underwater cameras. However, the repeatability of the detections is limited and further sensitivity studies are required.

Background: The rates of mental health disorders such as anxiety and depression are at an all-time high especially since the onset of COVID-19, and the need for readily available digital health care solutions has never been greater. Wearable devices have increasingly incorporated sensors that were previously reserved for hospital settings. The availability of wearable device features that address anxiety and depression is still in its infancy, but consumers will soon have the potential to self-monitor moods and behaviors using everyday commercially-available devices. Objective: This study aims to explore the features of wearable devices that can be used for monitoring anxiety and depression. Methods: Six bibliographic databases, including MEDLINE, EMBASE, PsycINFO, IEEE Xplore, ACM Digital Library, and Google Scholar were used as search engines for this review. Two independent reviewers performed study selection and data extraction, while two other reviewers justified the cross-checking of extracted data. A narrative approach for synthesizing the data was utilized. Results: From 2408 initial results, 58 studies were assessed and highlighted according to our inclusion criteria. Wrist-worn devices were identified in the bulk of our studies (n = 42 or 71%). For the identification of anxiety and depression, we reported 26 methods for assessing mood, with the State-Trait Anxiety Inventory being the joint most common along with the Diagnostic and Statistical Manual of Mental Disorders (n = 8 or 14%). Finally, n = 26 or 46% of studies highlighted the smartphone as a wearable device host device. Conclusion: The emergence of affordable, consumer-grade biosensors offers the potential for new approaches to support mental health therapies for illnesses such as anxiety and depression. We believe that purposefully-designed wearable devices that combine the expertise of technologists and clinical experts can play a key role in self-care monitoring and diagnosis.

In 1964, exploration drilling in the German Sector of the North Sea hit a gas pocket at ∼2900 m depth below the seafloor and triggered a blowout, which formed a 550 m-wide and up to 38 m deep seafloor crater now known as Figge Maar. Although seafloor craters formed by fluid flow are very common structures, little is known about their formation dynamics. Here, we present 2D reflection seismic, sediment echosounder, and multibeam echosounder data from three geoscientific surveys of the Figge Maar blowout crater, which are used to reconstruct its formation. Reflection seismic data support a scenario in which overpressured gas ascended first through the lower part of the borehole and then migrated along steeply inclined strata and faults towards the seafloor. The focused discharge of gas at the seafloor removed up to 4.8 Mt of sediments in the following weeks of vigorous venting. Eyewitness accounts document that the initial phase of crater formation was characterized by the eruptive expulsion of fluids and sediments cutting deep into the substrate. This was followed by a prolonged phase of sediment fluidization and redistribution widening the crater. After fluid discharge ceased, the Figge Maar acted as a sediment trap reducing the crater depth to ∼12 m relative to the surrounding seafloor in 2018, which corresponds to an average sedimentation rate of ∼22,000 m3/yr between 1995 and 2018. Hydroacoustic and geochemical data indicate that the Figge Maar nowadays emits primarily biogenic methane, predominantly during low tide. The formation of Figge Maar illustrates hazards related to the formation of secondary fluid pathways, which can bypass safety measures at the wellhead and are thus difficult to control.

This paper presents a methodological approach for the evaluation of the thermal behavior of cementitious porous media with/without integrated latent-heat thermal energy storage (LHTES). To achieve this goal, the Lewis-Nielsen model has been calibrated to predict the insulation properties of mineralized foamed concretes. Two pore-related microstructural fitting parameters, A and Φm, are presented according to the available data in the literature. In this regard, new findings are implemented for the classification of pore structure and prediction of the homogenized thermal conductivity of two-phase cementitious foams with or without phase change materials. The calibration and predictive analyses have been extended to a wide range of experimental data, including variation of binder types, porosities, and latent components. The presented analytical approach appears to agree well with experimental results and can be employed in the design of two-phase mineral foam materials. Then, to assess the thermal behavior of the predicted insulating envelopes, a one-dimensional (1D) enthalpy-based model is used which combines Fourier’s law of heat conduction, the first law of thermodynamics, Lewis-Nielsen conductivities, and the mixture theory for LHTES additions. The results demonstrated the importance of volumetric heat capacity for the thermal inertia of building envelopes.

Coastal wetlands depend on vertical accretion to keep up with sea level rise in cases where embankment restricts accommodation space and landward migration. For coastal wetland survival, autogenic productivity (litter, root decay) as well as allogenic matter input are crucial. Beach wrack composed of seagrass and algae can serve as an important allogenic matter source, increase surface roughness, elevate the backshore, and influence the blue carbon budget. The objective of this study is to understand how human footpaths in a frequently accessed Baltic coastal wetland influence beach wrack transport and accumulation. Beach wrack monitoring during the winter storm season 2021/2022 was conducted in high spatial and temporal resolution with bi-weekly UAV flights. Object-based identification, segmentation, and classification of orthophotos with open-source software allowed the detection of beach wrack patches with a mean area of 0.6–2.7 m². Three major storm events occurred during the monitoring period (Arwen, Malik, Eunice). Regardless of wind speed or direction, the main accumulation zones remained stable. The east-west footpath that crosses the coastal wetland and connects the tourist hotspots served as a “highway” for water-mediated transport of beach wrack. Total area covered by beach wrack fluctuated between 1,793 and 2,378 m² with a peak after storm Malik in January 2022. The densely accumulated beach wrack along the main east-west footpath formed an elongated micro-cliff-like structure and limited landward transport. Additional aerial image analysis for the last 15 years showed that the position of the footpaths remained stable. This pioneering study offers first insights into the fate of beach wrack in an anthropogenically influenced Baltic coastal wetland where larger tidal channels that usually generate hydrological connectivity are missing. The identified transport patterns and accumulation hotspots are a starting point for further research on how beach wrack behaves in (waterlogged) coastal wetlands compared to decomposition on sandy beaches.

In this experimental research a transparent thermoplastic manufactured by the DOW Corporation and known as Surlyn is investigated for use as an interface material in fabrication of an all-glass pedestrian bridge. The bridge is modular in construction and fabricated from a series of interlocking hollow glass units (HGU) that are geometrically arranged to form a compression dominant structural system. Surlyn is used as a friction-based interface between neighbouring HGUs preventing direct glass-to-glass contact. An experimental program consisting of axial loading of short glass columns (SGC) sandwiched between Surlyn sheets is used to quantify the bearing capacity at which glass fracture occurs at the glass-Surlyn interface location. Applied load cases include 100,000 cycles of cyclic load followed by 12 hours of sustained load followed by monotonic load to cracking, and monotonic loading to cracking with no previous load history. Test results show that Surlyn functions as an effective interface material with glass fracture occurring at bearing stress levels in excess of the column-action capacity of an individual HGU. Furthermore, load cycling and creep loading had no effect on the glass fracture capacity. However, the load history had a nominal effect on Surlyn, increasing stiffness and reducing deformation.

The Vacuum Insulated Glazing is a highly thermally insulating structure consisting of two (or more) glass sheets, separated by an evacuated gap, and sealed hermetically at the glass edges. An array of support pillars maintains the separation of the panes under the constant load of atmospheric pressure. The performance and durability of the VIG, in terms of thermal loads and atmospheric pressure, has been well studied and ISO Standards have recently been published (ISO 19916-1:2018 and 19916-3:2021). However, the mechanical performance of the VIG, especially when exposed to dynamic loads, has not been dealt with in the scientific literature. The goal of this work is to investigate the mechanical performance of VIG’s subjected to soft body impact and gain insight into the failure mechanisms of the VIG when exposed to dynamic loads. Measurements of the surface stress on the glass were performed, when the VIG is subjected to the twin-tire pendulum impact test, as outlined in the Standard DIN EN 12600:2002. Two VIG units and one laminated VIG unit were tested and the results were compared to numerical data of a monolithic glass pane. It was found that the VIG failed at drop heights much lower than that prescribed in the Standard. An examination of the glass fracture patterns highlighted an origin of fracture caused by the contact of pillar-to-glass.

The desire to apply annealed float glass with their economic and optical advantages is limited by the reduced edge strength due to the cutting process. The edge strength of annealed float glass is a decisive factor especially for insulating glazing due to temperature stress. In standards (e. g. DIN EN 18008), the edge strengths are reduced compared to the surface strength of annealed glass. This is mainly a result of the applied cutting process with the corresponding parameters and the glass handling after cutting. The type of cutting process and the cutting parameters (cutting wheels, etc.) have an effect on the development of micro cracks and thus also on edge strength. A defined cutting process allows reproducible and enhanced edge strength. This paper presents results of destructive and non-destructive investigations with regard to the edge strength. For the investigations, glass panes were cut on an industrial cutting machine with various process settings. Among other things, the following cutting parameters were varied: type of cutting wheel, cutting pressure, cutting speed and cutting fluid. In addition to the process parameters, different basic glasses, glass thicknesses and the cut process on the tin side were also investigated. The samples were examined with the aim to determine the correlations between the cutting process / glass parameters, the edge strength and the micro crack geometry and optimize the parameters. The destructive tests were carried out primarily with a modified four point bending test, but also with the standard four point bending test according to DIN EN 1288-3.

For the design of façade and roof glazing, loads due to dead weight, climatic loads (IGU - pressure differences), wind and snow are well investigated and are considered in engineering practice. However, glass constructions are also ex-posed to thermally induced stresses due to direct solar irradiation. The standards and guidelines available so far, both nationally and at the European level, are partly outdated or contain only simplified instructions and specifications for calculating thermally induced stresses of façade and roof glazing. Within the research project, a variety of façade glazing configurations and additionally building-integrated (BIPV) glass-glass photovoltaic modules, for example as a façade cladding rear ventilated, are being investigated by means of numerical simulation and subsequent experimental validation with up-to-date German meteorological data. The purpose of the project is to reduce or prevent the occurrence of thermally induced glass breakage (thermal breakage) through European standardization. In this way, economic damage can be avoided. The present paper provides an insight into the two-years lasting joint research project, including the current status of science and technology, goals, structure and process, and descriptions of work packages. Results, such as the collection of the various influencing factors, meteorological data, and results from numerical simulations, will be presented after the project has finished at the end of September 2022.

The birefringent properties of glass can be well utilized for non-destructive testing of thermally tempered glass. The surface compression stress as well as the compression zone depth of thermally tempered glass is commonly measured with a scattered light polariscope. The measurement with scattered light polariscope provides information about stresses acting perpendicular to the measurement direction. Therefore, the measurement depends on the direction. In order to make a statement about the rough level of the prestress, a measurement in one direction can be sufficient, assuming an isotropic stress state and a relatively homogeneous distribution of the surface compression stress. However, in order to be able to make a more detailed statement about a non-isotropic stress state, measurements in up to four directions are necessary. Information about the direction of principal stresses and differences of principal stresses can then be evaluated. In the present work, it is investigated which deviations can be expected by measurements performed in only one direction or by measurements using up to four directions. For this purpose, five methods are introduced, which deviate in the assumptions made for the current stress state. The methods are compared using measurements on thermally tempered glass in a four-point bending test and on thermally tempered glass specimens without any external load.

In the structural design of facade glazing, various types of loads such as dead weight, wind and climatic loads (pressure differences) must be taken into account. In practice, however, there are many cases of damage that can be attributed to direct solar radiation. In these cases, a so-called thermally induced fracture takes place, which can occur as a result of large in-plane temperature differences within the glass. Due to the increasing complexity of glazing constructions, this load type should be taken into account in future glass design. For this reason, thermal-mechanical investigations, were conducted. Commercially used double and triple insulating glass units were considered as vertical glazing and the solar direct absorptance per glass pane was varied. For numerical calculations, measured temperature data from the German Weather Service and free available Clear Sky model data were used as meteorological input. The results show that solar irradiance, along with temperature, is the driving influence on the thermally induced stress in insulating glass units. The investigations indicate that the inner pane becomes relevant on colder days and the outer pane on warmer days. Results also show, that the level of the outside temperature plays a negligible role for the thermally induced stresses of the middle pane.

Polyhedral Graphic Statics (PGS) is an effective tool for form-finding and constructing complex yet efficient spatial funicular structures. The intrinsic planarity of polyhedral geometries can be leveraged for efficient fabrication and construction using flat sheet materials, such as glass. Our previous research used PGS for the form-finding of a 3 m-span, modular glass bridge prototype to be built with thirteen unique hollow glass units (HGUs) in a compression-only configuration. This paper reports its design optimization, fabrication, and subsequent modular assembly process. The computational modeling of the geometries is facilitated with the efficient half-face data structure provided by PolyFrame, a software that implements PGS. Regular float glass and acrylic are selected as the main structural materials, and they are fabricated using 5-axis water jet cutting and CNC milling techniques. With the help of 3 M™ Very High Bond tape, the glass parts and acrylic parts are bonded as HGUs, which serve as the basic structural and assembly modules. Surlyn sheets are used as interface material to prevent glass-to-glass direct contact between HGUs. The digital model is also simulated using ANSYS to ensure the effectiveness of the design. Due to the lightweight of the HGUs, the assembly of the bridge can be done by one person without the requirement of any heavy construction machinery.

The bending strength of flat glass panels including the effects of their edges, is commonly determined by means of the four-point bending test method. This is an established and reliable method. However, when testing glass thinner than 3 mm, large deformation may occur. This means that the calculated stresses might not correspond to the actual, as the hypothesis behind the small deformation theory does no longer hold. Furthermore, it might occur that the specimen slips out of the supports, compelling the testing impossible. An alternative method, suitable for thin glass, consists of inducing an increasing curvature from flat until fracture. The curvature is to be constant along the length of the specimen at any time. The stress at fracture is calculated by knowing the corresponding radius or the applied bending moment. The equipment capable of performing this test is the clamp bender whereby the glass is held by two clamps at the specimen’s ends. Rotational and translational movement combine to uniaxially bend the glass as desired. This paper explores the validity of the clamp bender for testing thin glass by comparing the results generated by three different test setups developed at TU Darmstadt, TU Dresden and AGC. The three individually developed clamp bender setups follow the same principle, but present a few differences in actuation. Using these three clamp bender test setups, identical series of thin glass specimens were tested. The results showed that the glass fracture strength data coming from different setups match quite well one another. This paper discusses the different test setups and compares the obtained glass strength data. It contributes to the development of a universally applicable, simple and reliable test method for thin glass.

BackgroundAnxiety is a mental disorder characterized by apprehension, tension, uneasiness, and other related behavioral disturbances. One of the nonpharmacological treatments used for reducing anxiety is serious games, which are games that have a purpose other than entertainment. The effectiveness of serious games in alleviating anxiety has been investigated by several systematic reviews; however, they were limited by design and methodological weaknesses. ObjectiveThis study aims to assess the effectiveness of serious games in alleviating anxiety by summarizing the results of previous studies and providing an up-to-date review. MethodsWe conducted a systematic review of randomized controlled trials (RCTs). The following seven databases were searched: MEDLINE, CINAHL, PsycINFO, ACM Digital Library, IEEE Xplore, Scopus, and Google Scholar. We also conducted backward and forward reference list checking for the included studies and relevant reviews. Two reviewers independently carried out the study selection, data extraction, risk of bias assessment, and quality of evidence appraisal. We used a narrative and statistical approach, as appropriate, to synthesize the results of the included studies. ResultsOf the 935 citations retrieved, 33 studies were included in this review. Of these, 22 RCTs were eventually included in the meta-analysis. Very low–quality evidence from 9 RCTs and 5 RCTs showed no statistically significant effect of exergames (games entailing physical exercises) on anxiety levels when compared with conventional exercises (P=.70) and no intervention (P=.27), respectively. Although 6 RCTs demonstrated a statistically and clinically significant effect of computerized cognitive behavioral therapy games on anxiety levels when compared with no intervention (P=.01), the quality of the evidence reported was low. Similarly, low-quality evidence from 3 RCTs showed a statistically and clinically significant effect of biofeedback games on anxiety levels when compared with conventional video games (P=.03). ConclusionsThis review shows that exergames can be as effective as conventional exercises in alleviating anxiety; computerized cognitive behavioral therapy games and exergames can be more effective than no intervention, and biofeedback games can be more effective than conventional video games. However, our findings remain inconclusive, mainly because there was a high risk of bias in the individual studies included, the quality of meta-analyzed evidence was low, few studies were included in some meta-analyses, patients without anxiety were recruited in most studies, and purpose-shifted serious games were used in most studies. Therefore, serious games should be considered complementary to existing interventions. Researchers should use serious games that are designed specifically to alleviate depression, deliver other therapeutic modalities, and recruit a diverse population of patients with anxiety.

BackgroundSkin cancer is the most common cancer type affecting humans. Traditional skin cancer diagnosis methods are costly, require a professional physician, and take time. Hence, to aid in diagnosing skin cancer, artificial intelligence (AI) tools are being used, including shallow and deep machine learning–based methodologies that are trained to detect and classify skin cancer using computer algorithms and deep neural networks. ObjectiveThe aim of this study was to identify and group the different types of AI-based technologies used to detect and classify skin cancer. The study also examined the reliability of the selected papers by studying the correlation between the data set size and the number of diagnostic classes with the performance metrics used to evaluate the models. MethodsWe conducted a systematic search for papers using Institute of Electrical and Electronics Engineers (IEEE) Xplore, Association for Computing Machinery Digital Library (ACM DL), and Ovid MEDLINE databases following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines. The studies included in this scoping review had to fulfill several selection criteria: being specifically about skin cancer, detecting or classifying skin cancer, and using AI technologies. Study selection and data extraction were independently conducted by two reviewers. Extracted data were narratively synthesized, where studies were grouped based on the diagnostic AI techniques and their evaluation metrics. ResultsWe retrieved 906 papers from the 3 databases, of which 53 were eligible for this review. Shallow AI-based techniques were used in 14 studies, and deep AI-based techniques were used in 39 studies. The studies used up to 11 evaluation metrics to assess the proposed models, where 39 studies used accuracy as the primary evaluation metric. Overall, studies that used smaller data sets reported higher accuracy. ConclusionsThis paper examined multiple AI-based skin cancer detection models. However, a direct comparison between methods was hindered by the varied use of different evaluation metrics and image types. Performance scores were affected by factors such as data set size, number of diagnostic classes, and techniques. Hence, the reliability of shallow and deep models with higher accuracy scores was questionable since they were trained and tested on relatively small data sets of a few diagnostic classes.

Abstract The article confronts comparative research outcomes on factors that helped or hindered the educational success of immigrant youth and second generation in the past decades in several European countries with the institutional responses of European educational systems to the challenges of integrating a substantial number of refugee and other newly arrived children since 2014. Especially studies on the second generation – mostly the offspring of labour migrants – have revealed substantial differences in the long-term effects of specific institutional arrangements in the different systems that can – and should – serve as lessons for the potentially detrimental effects of the ways schools and school systems have reacted to the new influx of immigrant children. In the light of the lessons that could be learned from previous experiences with immigrant children and children of immigrants the article analyses in which way the current responses of different European educational systems to the presence of refugee and other immigrant children reflect these lessons, but also do justice to the particular challenges and specific situations of refugee youth that generally place them at an even higher disadvantage than other migrants. On the other hand, some of the ad-hoc measures for refugee pupils may have the potential of becoming permanent features of the respective educational systems.

Abstract Since the war in Syria started in 2011, many children left their war-torn country, alone or together with their families, and fled to neighboring countries in the Middle East, to Turkey or to Europe. This article will compare how Syrian refugee children are included – or not - in school systems both in Europe (Sweden, Germany and Greece) and outside Europe (Turkey and Lebanon). These five countries represent very different ways of receiving children in their educational system. We will compare national institutional arrangements like access to compulsory school, access after compulsory school age, welcome or immersion classes, second language education and tracking mechanisms. Including children as soon as possible in regular classes seems to provide the best chances for school success, whereas educating refugee children in a segregated parallel school system for extended periods often results in early school leaving or not attending school at all.

In the practical application of the Bridge Weigh-In-Motion (BWIM) methods, the position of the wheels or axles during the passage of a vehicle is a prerequisite in most cases. To avoid the use of conventional axle detectors and bridge type-specific methods, we propose a novel method for axle detection using accelerometers placed arbitrarily on a bridge. In order to develop a model that is as simple and comprehensible as possible, the axle detection task is implemented as a binary classification problem instead of a regression problem. The model is implemented as a Fully Convolutional Network to process signals in the form of Continuous Wavelet Transforms. This allows passages of any length to be processed in a single step with maximum efficiency while utilising multiple scales in a single evaluation. This allows our method to use acceleration signals from any location on the bridge structure and act as Virtual Axle Detectors (VADs) without being limited to specific structural types of bridges. To test the proposed method, we analysed 3787 train passages recorded on a steel trough railway bridge of a long-distance traffic line. Results of the measurement data show that our model detects 95% of the axles, which means that 128,599 out of 134,800 previously unseen axles were correctly detected. In total, 90% of the axles were detected with a maximum spatial error of 20 cm, at a maximum velocity of vmax=56.3m/s. The analysis shows that our developed model can use accelerometers as VADs even under real operating conditions.

Laminated safety glass (LSG) is increasingly used as structural element in buildings. Of central importance for safety are the adhesion and the residual load-bearing capacity in the post fractured state. In literature a large number of tests to assess adhesion is mentioned. These include, e.g. peel tests, through-cracked-tensile/-bending tests, VW-pull tests and compressive shear tests. However, especially in industry, the Pummel test is widespread for determining the quality of adhesion in LSG with polyvinyl butyral based interlayers. This test method proves to be simple and quick to carry out: The laminate is stored at − 18 °C and then completely destroyed at room temperature with hammer blows. The adhesion level (0–10) is determined by visually comparing the adhering glass fragments with reference pictures or with the help of diagrams and tables which indicate the Pummel value as a function of the free film surface. Pummel value 0 is to be interpreted as no adhesion and Pummel value 10 as very high adhesion. Due to the lack of standardization, the execution and evaluation is very much dependent on the test institution and executive person. This paper shows different Pummel classifications that can currently be found on the market. Subsequently, approaches to the automatization and standardization of the execution and especially the evaluation of the Pummel test are shown. Three image evaluation methods in Matlab are presented, discussed and compared: (1) analysis of binary images, (2) statistical evaluation of the greyscale images and (3) texture analysis using co-occurrence matrices.

The strength of glass plays an important role in the dimensioning of glass components in the building industry. Here, not only parameters such as support conditions, loading rate, relative humidity etc. play an important role, but the damage by means of scratches also determines the fracture strength of glass. A heat treatment after damaging may have an influence on the resulting glass strength. The correlation between heat treatment temperature, and in particular elevated temperatures up to the glass transition temperature, and fracture stress has been studied by different researchers with several approaches of pre-treatment of specimens and test setups. This paper methodically presents various preliminary investigations which were carried out within the framework of the pre-treatment of the samples in order to investigate the influence of heat treatment of the pre-damaged samples on the fracture stress. For this purpose, double ring bending tests were performed at room temperature on pre-damaged, heat-treated soda–lime silicate glass specimens. The aim of the investigations is to obtain estimates of the extent to which a heat treatment prior to the strength test influences the fracture strength of soda–lime silicate glass. Parameters like the heat treatment temperature, the dwell time of the samples inside the furnace and the furnace design were considered. The results show that the heat treatment can increase the fracture stress of soda–lime silicate glass as float glass significant due to an assumed healing of the pre-damage during heat treatment.

Photovoltaic modules in desert areas benefit from high irradiation levels but suffer from harsh environmental stress factors, which influence the Levelized Cost of Electricity by decreasing the lifetime and performance and increasing the maintenance costs. Using optimized half-cell module designs mounted in the most efficient orientation according to the plant requirements can lead to reduced production costs, increased energy yield and longer service lives for PV modules in desert areas. In this work, we review the technical advantages of half-cell modules in desert regions and discuss the potential gains in levelized costs of electricity due to reduced material consumption, a higher cell-to-module power ratio, lower module temperatures, better yields, reduced cleaning cycles and finally, reduced fatigue in interconnection due to thermal cycling. We show that half-cell modules are the most cost-effective option for desert areas and are expected to have a relevant lower Levelized Cost of Electricity.

Acoustic seafloor measurements with multibeam echosounders (MBESs) are currently often used for submarine habitat mapping, but the MBESs are usually not acoustically calibrated for backscattering strength (BBS) and cannot be used to infer absolute seafloor angular dependence. We present a study outlining the calibration and showing absolute backscattering strength values measured at a frequency of 150 kHz at around 10–20 m water depth. After recording bathymetry, the co-registered backscattering strength was corrected for true incidence and footprint reverberation area on a rough and tilted seafloor. Finally, absolute backscattering strength angular response curves (ARCs) for several seafloor types were constructed after applying sonar backscattering strength calibration and specific water column absorption for 150 kHz correction. Thus, we inferred specific 150 kHz angular backscattering responses that can discriminate among very fine sand, sandy gravel, and gravelly sand, as well as between bare boulders and boulders partially overgrown by red algae, which was validated by video ground-truthing. In addition, we provide backscatter mosaics using our algorithm (BBS-Coder) to correct the angle varying gain (AVG). The results of the work are compared and discussed with the published results of BBS measurements in the 100–400 kHz frequency range. The presented results are valuable in extending the very sparse angular response curves gathered so far and could contribute to a better understanding of the dependence of backscattering on the type of bottom habitat and improve their acoustic classification.

Le traité de Meersen, qui partage le royaume lotharingien en 870 entre Charles le Chauve et Louis le Germanique, constitue un document d’importance majeure, aussi bien pour l’étude de la géographie politique du ixe siècle que pour celle des techniques de sauvegarde d’information spatiale durant le premier Moyen Âge. Les informations fournies par ce traité, qui permettent de reconstruire le partage de Verdun de 843, posent plusieurs problèmes sur la partition concrète des regna en Frise, en Rhénanie et en Franche-Comté. Cet article propose une réponse aux questions liées à la situation dans l’espace jurassien en exploitant l’histoire de ses fondations monastiques.Il s’agit là d’une tentative de spatialisation des établissements religieux du diocèse de Besançon, afin de voir si cette approche peut apporter de nouvelles connaissances concernant non seulement la perception des entités spatiales au haut Moyen Âge, mais aussi nos connaissances concrètes sur le sujet, ainsi que sur l’histoire des institutions politiques et monastiques.

Cavitation in rubber-like materials describes sudden void growth of an initially voided material under hydrostatic tension until the material fails. To study the cavitation effect numerically, classical cavitation criteria are coupled with a continuum damage formulation of a Neo-Hookean material. A cavitation criterion defines a failure surface in threedimensional stress or strain space, which represents the onset of excessive void growth and therefore the strong degradation of the bulk modulus. To account for this special case of material softening, a novel continuum damage formulation at finite strains is presented, where the initially constant bulk modulus of a hyperelastic material is reduced after satisfying a cavitation criterion. Since this formulation leads to an abrupt damage initiation, additionally a continuously volumetric damage formulation is proposed and compared with it. Therefore, novel void growth criteria are developed, which describe the cavitation effect even under smallest volumetric strains. For numerical validation, a single element test is simulated under hydrostatic tension. Furthermore, pancake tests are numerically analysed. The results with regard on the chosen cavitation criterion and the abrupt/continuously damage formulation are compared with each other analysing TSSA.

A trend towards adhesive connections instead of mechanical ones can be observed for transparent facades in recent years. Furthermore, research efforts are made to increase the efficiency regarding material use by designing systems with composite structural behavior. In this article, experimental and numerical results obtained for linear structural silicone joints between glass and stainless steel substrates, investigated separately under tensile and under shear loading, are discussed. The two selected adhesives, Dow Corning® 993 and Sikasil® SG-550, are approved for structural sealant glazing systems and are planned to be used within a novel concept for façade elements with composite structural behavior, consisting of a glass pane and a filigree metal framing. For an adhesive joint with prismatic geometry, the influence of different lengths, widths and thicknesses of the joint on its mechanical performance is assessed experimentally under tensile loading, while under shear loading only different thicknesses are investigated. Both under tensile and under shear loading, a dependency of the failure engineering stresses on the joint thickness is noticed. In a second step, the suitability of selected hyperelastic models is assessed for predicting the load versus displacement behavior of the investigated linear adhesive joints. The parameters required for these models are determined based on uniaxial tensile tests on dumbbell specimens.

This work presents the relation between the fragment density and the permanent residual stress in fragmented tempered glasses of various thicknesses. Therefore, fracture tests were carried out on tempered glass plates and the fragments in observation fields of 50 mm × 50 mm were counted. The average fragment density in the observation fields was set in correlation with the average measured residual stress of each specimen. Furthermore, the average particle weight of 130 particles per specimen chosen by random was determined. The relation between the average particle weight and the measured residual stress is given. The volume and the base surface as well as the radius of the particles are calculated assuming cylindrical fragments with approximately unchanged thicknesses. The relation between the residual stress and the particle base surface of regular polygonal shapes n=3–8 edges in addition to the cylindrical fragment (n→∞) is also determined. The glass used for the fracture tests was commercial soda-lime-silica glass with three different thicknesses 4, 8 and 12 mm. The results in this work are a basis for the establishment of a theoretical model to predict macro-scale fracture patterns from elastic strain energy in tempered glass.

Glass is an indispensable material in the building industry. The combination of transparency, strength and durability makes it to an unparalleled and desirable material. The technology additive manufacturing (AM) has a potential in the building industry, based on a relatively small amount of repetitions of particular building components and the tendency of applying technology innovations for buildings. Therefore, there is an interest for additive manufacturing with glass. This paper presents and summarizes the results of the preliminary research regarding additive manufacturing of glass components for joining methods for flat glass structures. Different types of glass (borosilicate glass, quartz glass and soda lime silicate glass) are discussed. Experimental investigations of joints are intended to illustrate the performance and potential of AM glass components in case of structural use. Load bearing tests were carried out to quantify the strength and load bearing capacity level of an AM structural component. The thermal residual stresses were examined by photo-elastic tests with polarized lights and scattered light method. The investigations show in principle that load transfer via fused glass joints is possible. The performed research activity is a first step towards the Additive Manufacturing of glass structures on flat glass.

Laminated safety glass has become an indispensable component in building construction, automotive and solar industry. It consists of at least two glass panes, that are laminated together with a polymeric interlayer. Mechanically speaking, the polymeric interlayer enables a shear transfer between the two glass panes. Here, the difficulty lies in the understanding of the real shear transmission. On the one hand, polymeric interlayers show a time dependent material behaviour, which can be described with a ‘Prony-series’ in the linear viscoelastic area. On the other hand, polymeric interlayers show a temperature dependent material behaviour. Hence, a Prony-series is only valid for one specific temperature. However, since relaxation is based on molecular movements and rearrangement processes, which can be thermally activated, an increase in temperature leads to an acceleration of the relaxation process. The time-temperature correlation can be taken into account by means of a ‘Time-Temperature-Superposition-Principle’ (TTSP). The relaxation curve of a thermorheologically simple material shifts solely horizontal along the time axis due to temperature changes, while its shape remains constant. Mathematically, this means, that all relaxation times of the Prony-series are multiplied by the same shift factor aT. Recent research of the authors shows, that some polymeric interlayers don’t follow a simple TTSP. The experimental identification through ‘Dynamical-Mechanical-Thermal-Analysis’ as well as ‘Differential Scanning Caliometry’ and numerical incorporation of this thermorheologically complex material behaviour into state-of-the-art Finite-Element-Software will be investigated on the example of ‘Ethylene-vinyl acetate’ in the following paper.

Several acoustic and optical techniques have been used for characterizing natural and anthropogenic gas leaks (carbon dioxide, methane) from the ocean floor. Here, single-camera based methods for bubble stream observation have become an important tool, as they help estimating flux and bubble sizes under certain assumptions. However, they record only a projection of a bubble into the camera and therefore cannot capture the full 3D shape, which is particularly important for larger, non-spherical bubbles. The unknown distance of the bubble to the camera (making it appear larger or smaller than expected) as well as refraction at the camera interface introduce extra uncertainties. In this article, we introduce our wide baseline stereo-camera deep-sea sensor bubble box that overcomes these limitations, as it observes bubbles from two orthogonal directions using calibrated cameras. Besides the setup and the hardware of the system, we discuss appropriate calibration and the different automated processing steps deblurring, detection, tracking, and 3D fitting that are crucial to arrive at a 3D ellipsoidal shape and rise speed of each bubble. The obtained values for single bubbles can be aggregated into statistical bubble size distributions or fluxes for extrapolation based on diffusion and dissolution models and large scale acoustic surveys. We demonstrate and evaluate the wide baseline stereo measurement model using a controlled test setup with ground truth information.

Corynebacterium glutamicum shows great potential for the production of the glutamate-derived diamine putrescine, a monomeric compound of polyamides. A genome-scale stoichiometric model of a C. glutamicum strain with reduced ornithine transcarbamoylase activity, derepressed arginine biosynthesis, and an anabolic plasmid-addiction system for heterologous expression of E. coli ornithine decarboxylase gene speC was investigated by flux balance analysis with respect to its putrescine production potential. Based on these simulations, enhancing glycolysis and anaplerosis by plasmid-borne overexpression of the genes for glyceraldehyde 3-phosphate dehydrogenase and pyruvate carboxylase as well as reducing 2-oxoglutarate dehydrogenase activity were chosen as targets for metabolic engineering. Changing the translational start codon of the chromosomal gene for 2-oxoglutarate dehydrogenase subunit E1o to the less preferred TTG and changing threonine 15 of OdhI to alanine reduced 2-oxoglutarate dehydrogenase activity about five fold and improved putrescine titers by 28%. Additional engineering steps improved further putrescine production with the largest contributions from preventing the formation of the by-product N-acetylputrescine by deletion of spermi(di)ne N-acetyltransferase gene snaA and from overexpression of the gene for a feedback-resistant N-acetylglutamate kinase variant. The resulting C. glutamicum strain NA6 obtained by systems metabolic engineering accumulated two fold more putrescine than the base strain, i.e., 58.1 ± 0.2 mM, and showed a specific productivity of 0.045 g·g−1·h−1 and a yield on glucose of 0.26 g·g−1.

Background. Arterial ex situ back-table perfusion (BP) reportedly reduces ischemic-type biliary lesion after liver transplantation. We aimed to verify these findings in a prospective investigation. Methods. Our prospective, randomized, controlled, multicenter study involved livers retrieved from patients in 2 German regions, and compared the outcomes of standard aortic perfusion to those of aortic perfusion combined with arterial ex situ BP. The primary endpoint was the incidence of ischemic-type biliary lesions over a follow-up of 2 years after liver transplantation, whereas secondary endpoints included 2-year graft survival, initial graft damage as reflected by transaminase levels, and functional biliary parameters at 6 months after transplantation. Results. A total of 75 livers preserved via standard aortic perfusion and 75 preserved via standard aortic perfusion plus arterial BP were treated using a standardized protocol. The incidence of clinically apparent biliary lesions after liver transplantation (n = 9 for both groups; P = 0.947), the 2-year graft survival rate (standard aortic perfusion, 74%; standard aortic perfusion plus arterial BP, 68%; P = 0.34), and incidence of initial graft injury did not differ between the 2 perfusion modes. Although 33 of the 77 patients with cholangiography workups exhibited injured bile ducts, only 10 had clinical symptoms. Conclusions. Contrary to previous findings, the present study indicated that additional ex situ BP did not prevent ischemic-type biliary lesions or ischemia-reperfusion injury after liver transplantation. Moreover, there was considerable discrepancy between cholangiography findings regarding bile duct changes and clinically apparent cholangiopathy after transplantation, which should be considered when assessing ischemic-type biliary lesions.