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Building "without land take" - current state of land take in Germany
No full textBased on the United Nations Agenda 2030 the government of Germany has formulated a national sustainability strategy which seeks to mitigate the ongoing increase in land take and aims for a circular economy until the year 2050 instead. Despite these political efforts, more land has been converted to building land in recent years. As part of a recent research project at Hamburg University of Technology, a preliminary study on land-take in Germany has been carried out as first milestone. Drivers of land take in recent years have been the regions of north-eastern, western and south-western Germany, while in centre regions a notable decrease in daily land take could be observed. The northern metropolitan areas mostly reported decreasing rates in their urban centres while land take increased in their suburban and greater areas. In contrast a densification of urban centres could be observed in the southern regions, while the surrounding rural areas showed decreasing or neutral trends. Only few counties reported a consistent negative land take over the recent years. Additional findings indicate that land take came almost exclusively at the expense of agricultural areas. In combination with recent efforts of afforestation backed up by comprehensive environmental protection laws, the available arable land quickly decreased over the recent years. To challenge this ongoing problem, the research project takes a novel approach on the design of large-scale commercial real estate by combining these buildings with commercial agriculture. A project outline is given at the end of the paper
Analyzing Multimodal Integration in the Variational Autoencoder from an Information-Theoretic Perspective
No full textHuman perception is inherently multimodal. We integrate, for instance, visual, proprioceptive and tactile information into one experience. Similarly, multimodal learning is of importance for building robotic systems that aim at robustly interacting with the real world. One potential model that has been proposed for multimodal integration is the multimodal variational autoencoder. A variational autoencoder (VAE) consists of two networks, an encoder that maps the data to a stochastic latent space and a decoder that reconstruct this data from an element of this latent space. The multimodal VAE integrates inputs from different modalities at two points in time in the latent space and can thereby be used as a controller for a robotic agent. Here we use this architecture and introduce information-theoretic measures in order to analyze how important the integration of the different modalities are for the reconstruction of the input data. The VAE is trained via the evidence lower bound, which can be written as a sum of two different terms, namely the reconstruction and the latent loss. The impact of the latent loss can be weighted via an additional variable, which has been introduced to combat the problem of posterior collapse. Another approach to improve a VAE is to use an aggregated posterior in the latent loss. Here we train networks with three different weighting schedules and one network with an aggregated posterior and analyze them with respect to their capabilities for multimodal integration
Enhancing the lifespan of steel structures through a 3D-printed coating device for the application of a nanometallic multilayer on weld seams
No full textGiven the substantial environmental and economic consequences associated with deteriorating infrastructure, prolonging the service life of steel bridges is essential for advancing sustainability and economic viability. A critical factor in achieving this goal is enhancing the integrity of welded joints, which play a pivotal role in the bridge’s performance under dynamic loading conditions. Research indicates that the fatigue strength of welds can be increased by up to sixfold through the application of a nanometallic multilayer (NMM) composed of nickel and copper. To date, investigations into the fatigue enhancement of welded joints using NMM have predominantly been conducted on a laboratory scale. To enable practical application on existing infrastructure, a coating device is being developed to apply the NMM treatment directly onto surfaces without the need for full immersion in an electrolyte bath, thus supporting its implementation as a post-treatment process for steel bridges
Heterogeneity in health insurance choice: An experimental investigation of consumer choice and feature preferences
No full textWe investigate heterogeneity in health insurance choice using data from a controlled laboratory experiment. Participants make consecutive choices from sets of insurance plans that vary in premium, deductible, and complementary coverage of illnesses. We find that there is considerable heterogeneity in how much individuals are willing to pay for certain plan attributes. To better understand these differences, we account for individual risk preferences using a rank-dependent expected utility (RDEU) model and assess the welfare effects of plan choices. At the aggregate level, we find welfare losses under both the normative RDEU model and the descriptive EV model. At the individual level, however, the results are more differentiated: for some individuals, choices are consistent with their RDEU preferences, whereas for others, choices do not fit either model, suggesting either decision errors or reliance on heuristics
Enhancing fatigue performance by tuning of residual stresses in welded joints through nanometallic multilayer
No full textWelded joints suffer from reduced fatigue life due to geometric stress concentrations and metallurgical changes in the heat-affected zone that promote crack initiation under cyclic loading. This study investigates a novel postweld treatment, utilizing a Cu/Ni nanometallic multilayer thin film deposited onto the welded butt joint. Deposition current densities and individual Cu/Ni layer thicknesses are systematically varied to optimize fatigue performance. A multiscale residual stress (RS) analysis characterizes stress states within individual multilayers and in the steel substrate, indicating all substrate RS are compressive in nature after thin film deposition. Results demonstrate a direct correlation between compressive RS magnitude and fatigue strength improvement. Tested at ΔσR = 0.75 × fy, a more than a 300% increase in cycles to failure is seen compared to the as-welded condition. This postweld treatment offers a promising approach for extending the operational life of welded structures across industrial applications
Evaporation dynamics from flowing water surfaces
No full textIn contrast to the wealth of information on evaporation dynamics from placid water surfaces such as lakes and reservoirs, estimating water evaporation from turbulent surfaces of streams remains a challenge. Evidence suggests a considerable change in evaporation from flowing surfaces relative to placid surfaces with local modifiers such as chemical, physical and biological processes that alter the energy budget and water temperature. While the studies on evaporation from wavy surfaces of oceans offer valuable insights, significant differences in hydrodynamics and heat exchange processes distinguish evaporation in oceans from that in rivers. Here we experimentally investigate how water flow characteristics (velocity and turbulence) and atmospheric boundary conditions (wind and radiation) affect evaporation rates and temperature dynamics in a flume. A closed flume (7.6 m length, 0.31 m width, and 0.5 m depth) is used to impose different boundary conditions over a test section of the flume (length of 1.5 m) while other parts of the flume are covered to reduce evaporative losses. Our preliminary findings show significant enhancement in evaporation rates, reaching 2-5 times that of placid water surfaces, driven by increases in surface velocity and turbulence characteristics. Furthermore, we observe that radiative and aerodynamic factors contribute nonlinearly to evaporation enhancement and affect temperature distribution in the water body. The study offers novel insights into evaporation from wavy and turbulent flowing water surfaces for better prediction of evaporation from riverine networks across flow regimes and climatic conditions.Deutsche Forschungsgemeinschaft (DFG
Virtues and rules in war: military ethics and technologies of radical risk-reduction
No full textOn a contentious but still widely held view of the ethics of war, belligerents’ mutual imposition of risk licenses the harm they attempt to inflict upon each other. When this reciprocity of risk imposition is lost—when combatants of one side are able to inflict harm without exposing themselves to it—the moral balance is disrupted. Technologies that radically reduce risk, such as UAVs (drones) or autonomous weapon systems, are particularly challenging in this respect. Scholars have suggested that these technologies of radical risk reduction are so morally disruptive that the ethics of war should fundamentally shift from virtue-based towards rule-based approaches. According to this view, since the traditional martial virtues (such as courage and mercy) are of little practical relevance to certain forms of modern warfare, drone pilots and other soldiers who dole out violence from great distances would be better served by clear moral rules. We argue, however, that this view is mistaken. That technologies of radical risk reduction bring some disruption to the martial virtues is undeniable, but the disruption is far less severe than has been suggested. We present an alternative account of the moral disruption caused by technologies of radical risk-reduction, highlighting how the changing nature of warfare is informing changes in what morality and virtue demand in war. Martial virtues continue to play a crucial role in ethical decision-making, as the moral performance of drone pilots in Ukraine has clearly demonstrated. We continue to have, therefore, strong reasons to educate and entrench a conception of the ‘virtuous warrior’ in today’s soldiers
Method for determining the stiffness of milling robots in-process using internal sensor data
No full textRobots pose many benefits for manufacturing, including a high flexibility, low investment cost, and a small footprint compared to conventional milling machines. Their usability is limited because of a high likelihood of chatter and a comparatively low accuracy. Exact knowledge of the robot’s stiffness can be used to compensate for accuracy errors due to static deflection. The identification of the robot’s stiffness is typically a laborious process, as the stiffness model is usually not provided by the robot’s manufacturer. In this article, a method for identifying the stiffness of a milling robot using solely data from internal sensors is presented. The usage of a rotary dynamometer for force measurements and secondary encoders for joint deflection measurements is motivated by eliminating the need for costly external measurement equipment. Additionally, the data generation for the proposed method can be conducted during milling, reducing the downtime of the robot and enabling an in-process stiffness identification. Using up-to-date data also allows for detecting changes in the stiffness, e.g., due to wear. The identified local Cartesian stiffness can be used to optimize milling paths to reduce static deflection and therefore improve milling accuracy
Vector-valued Fourier hyperfunctions and boundary values
No full textThis work is dedicated to the development of the theory of Fourier hyperfunctions in one variable with values in a complex non-necessarily metrizable locally convex Hausdorff space E. Moreover, necessary and sufficient conditions are described such that a reasonable theory of E-valued Fourier hyperfunctions exists. In particular, if E is an ultrabornological PLS space, such a theory is possible if and only if E satisfies the so-called property (PA). Furthermore, many examples of such spaces having (PA) (resp. not having (PA)) are provided. We also prove that the vector-valued Fourier hyperfunctions can be realized as the sheaf generated by equivalence classes of certain compactly supported E-valued functionals and interpreted as boundary values of slowly increasing holomorphic functions
Microplastic-induced alterations in water flow and solute transport dynamics in soil
No full textThe growing use of plastic-based practices in agriculture has led to a significant accumulation of plastic waste in soil. Microplastics (MPs) increasingly threaten soil health and fertility by disrupting its physical and chemical environment, and impairing essential ecological functions. We conducted laboratory column measurements combined with microfluidic experiments to assess the effects of MPs on water flow and solute transport in soil, key processes for sustaining soil water and nutrient availability and thus crop growth and yield. Changes in hydraulic conductivity and solute breakthrough curves in sandy soils were investigated in the presence of varying concentrations of polyethylene (PE) and polyvinylchloride (PVC) microplastics. Alterations in pore structure and clogging of pore throats by MPs, as further evidenced through confocal and fluorescence microscopy of synthesized porous media, led to 39% and 74% reductions in hydraulic conductivity of sand samples containing 5% PVC and 5% PE, respectively. Solute transport experiments using a brine tracer revealed broader breakthrough curves in the presence of MPs. Overall, the enhancement of pore-scale flow heterogeneity driven by the development of preferential flow paths and the formation of low-permeability zones increased hydrodynamic dispersion and resulted in both early breakthrough and delayed transport of the tracer within the soil column