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touristic/landscape. a strategy to (un)build a refuge.
No full textDas heutige Eingreifen in die Landschaft ist viel stärker vom Menschen geprägt, als wir es zugeben wollen. Die fortschreitende Zersiedlung, die zunehmende Versiegelung durch Freizeit- und Tourismusinfrastrukturen sowie die „Inszenierung“ der Berge sind Entwicklungen, die kritisch hinterfragt werden müssen. Intakte Natur und funktionierende Ökosysteme sind nach wie vor elementare Ressourcen, auf denen touristischer Erfolg basiert. Dennoch ist der Umgang mit ihnen stark vom angestrebten wirtschaftlichen Erfolg des Tourismus geprägt.Die Arbeit untersucht den Wandel alpiner Baukultur zwischen architektonischer Tradition und Transformation am Beispiel der italienischen Region Trentino-Südtirol. Im Fokus stehen die Entwicklungen der Landschaften, Ortsbilder und gebauten Strukturen, die seit dem 20. Jahrhundert tiefgreifenden Veränderungen unterliegen. Diese bedingt durch sozioökonomische und politische Umbrüche, sowie insbesondere den Einfluss des (Über)Tourismus. Dieser Wandel von einer Landschaft zur Tourismuslandschaft wurde in einem fotografischen, kartografischen und historischen Dialog festgehalten. Der vorliegende Entwurf diskutiert vor dem Hintergrund aktueller klimatischer Herausforderungen eine zeitgemäße Renaissance der „Sommerfrische“. Dieses Phänomen ist zwar nicht neu, erscheint jedoch im Kontext urbaner Überhitzung und steigendem Ressourcenverbrauch aktueller und relevanter denn je. Ein neuer Aufschwung darf allerdings nicht als flächige Expansion verstanden werden, die weiteren Leerstand und Landschaftsverbrauch provoziert. Er muss vielmehr situativ und sensibel am Bestand und im alpinen Kontext ansetzen. Durch eine Revitalisierung soll ein ungenutzter touristischer Bestand in eine zukünftige, temporäre und gemeinschaftliche Wohnform umgewandelt werden, um einen sanften und nachhaltigen Tourismus einzuleiten. Prinzipien des modernen Holzbaus sowie der Logik der vernakulären Bauweise bilden den Rahmen für die neue Typologie. Im Vordergrund stehen die Wiederverwendung von Baumaterialien und Strategien für eine flexible temporäre Nutzung. Es wird der Versuch unternommen, ein modulares, rückbaubares und landschaftsverträgliches Tourismusmodell zu konzipieren, das Landschaft als gemeinschaftlich genutztes Gut versteht. Die Architektur von heute bildet den zukünftigen Bestand und muss den aktuellen und zukünftigen klimatischen sowie sozialen Herausforderungen gerecht werden.Today's landscape is much more influenced by humans than we are willing to admit. Ongoing urban sprawl, the growing impermeabilization of land through leisure and tourism infrastructure, and the deliberate 'staging' of mountain scenery are developments that demand critical scrutiny. Intact nature and functioning ecosystems remain fundamental resources for sustained tourism success. Yet, how these are managed is increasingly dictated by the pursuit of economic gain in tourism.This work examines the transformation of Alpine building culture between architectural tradition and transformation, using the Italian region of Trentino–South Tyrol as a case study. The focus lies on the evolution of landscapes, townscapes, and built structures, all of which have undergone profound changes since the 20th century. This transformation has been shaped by socio-economic and political upheaval, and, in particular, by the influence of overtourism. The gradual shift from an landscape toward a 'tourism landscape' has been documented through a photographic, cartographic, and historical dialogue. Against the backdrop of current climatic challenges, this proposal discusses a contemporary renaissance of the Alpine ‘Sommerfrische’, the tradition of summer holidays in the Alps. While not a new phenomenon, it appears more relevant now than ever, in the face of urban overheating and soaring resource consumption. This new wave of adaptation, however, must not be seen as a widespread expansion that risks aggravating vacancy rates and unchecked land consumption. Transformations must be context-sensitive, focusing on the existing building stock and the realities of the Alpine setting. Unused tourist accommodation should be revitalised to serve as a future, temporary, sustainable, and communal form of living, and to initiate slow tourism. Principles of modern timber construction and the logic of vernacular building form the framework for the new typology. Central to the concept are the reuse of building materials and strategies for flexible, temporary habitation. The aim is a modular, demountable, and landscape-compatible model – one that treats the landscape as a common good. Architecture today forms the building stock of tomorrow and must address both present and future climatic and social challenges
Center for Open Science: Strategic Plan
No full textThe Center for Open Science (COS) has a mission to increase the openness, integrity, and trustworthiness of research. During the next three years, we will demonstrate, improve, and promote pathways for doing and consuming lifecycle open science. This represents a convergence of our infrastructure, research, policy, and capacity building activities over the last decade to a singular true north objective. Our strategic objective is supported by a systems-level theory of change and an engagement strategy that meets communities at their readiness to consider, test, adapt, and adopt new practices and norms. By assessing current practices, reimagining research, offering open science infrastructure and solutions, and building community capacity, we partner with a global community of change agents to shift culture and practice to increase research trustworthiness and accelerate progress
Welfare tradeoff psychology is present in children and adults
No full textMaking decisions in a social context often requires weighing one's own wants against the needs and preferences of others. Adults are adept at incorporating multiple contextual features when deciding how to trade off their welfare against another. For example, they are more willing to forgo a resource to benefit friends over strangers (a feature of the individual) or when the opportunity cost of giving up the resource is low (a feature of the situation). When does this capacity emerge in development? In Experiment 1 (N = 208), we assessed the decisions of 4- to 10-year-old children in a picture-based resource tradeoff task to test two questions: (1) When making repeated decisions to either benefit themselves or benefit another person, are children’s choices internally consistent with a particular valuation of that individual? (2) Do children value friends more highly than strangers and enemies? We find that children demonstrate consistent person-specific welfare valuations and value friends more highly than strangers and enemies. In Experiment 2 (N = 200), we tested adults using the same pictorial method. The pattern of results successfully replicated, but adults’ decisions were more consistent than children’s and they expressed more extreme valuations: relative to the children, they valued friends more and valued enemies less. We conclude that despite children’s limited experience allocating resources and navigating complex social networks, they behave like adults in that they reference a stable person-specific valuation when deciding whether to benefit themselves or another and that this rule is modulated by the child’s relationship with the target
A variational method to wear with embedded roughness
Get PDFA variational approach to contact mechanics with friction for the prediction of wear evolution under various indenters is proposed in this work. The contact problem is solved using the eMbedded Profile for Joint Roughness (MPJR) interface finite elements, here advanced to predict wear arising from the frictional contact problem between an indenter of any complex shape and an elastic body. The interface finite element formulation embeds the indenter shape, roughness, or any general deviation from planarity directly in the computation of the normal gap, updating the indenter geometry in time to account for the effect of wear through a microscopically postulated local Archard adhesive wear model. The formulation employs a regularized Coulomb law of friction to compute the tangential contact response, while a penalty approach is used to enforce the unilateral contact constraint. The methodology is exploited to get an insight into the complex relation between the macroscopically emergent global wear effects and the wear law at the microscale, which are intrinsically coupled through geometrical effects. To show the model predictive capability, the numerical examples consider three different indenter profiles with flat, cylindrical, and rough geometry
Entwicklung eines aktorisierten Werkzeugsystems für das niederfrequente schwingungsunterstützte Polierschleifen
Get PDFDie Feinbearbeitung sprödharter Werkstoffe wie Keramiken oder Gläser stellt eine technologische und wirtschaftliche Herausforderung dar. Eine Schwierigkeit besteht hierbei in der Erzielung geringer Rauheitswerte in der fertigungstechnischen Prozesskette. Es sind zumeist mehrere Bearbeitungsschritte mit unbestimmter Schneide für diese Art der Zerspanung notwendig. Hierbei werden schwingungsunterstützte Prozessvarianten, die zu den hybriden Fertigungsverfahren zählen, vielfach eingesetzt. Eine typische Ausprägung eines hybriden Feinbearbeitungsprozesses ist die schwingungsunterstützte Bearbeitung durch die Querumfangsfläche mit rotierenden stiftförmigen Werkzeugen. Bei diesem hybriden Prozess wird die Schwingung durch eine zusätzliche Relativbewegung in Richtung der Rotationsachse des Werkzeugs realisiert. Für diese Bearbeitung haben sich Systeme im Frequenzbereich von bis zu 50 kHz bewährt. Dabei werden Werkzeuge mit gebundenen Körnern unterhalb von 15 μm Korngröße verwendet. Der mittlere Korndurchmesser am Ende der Prozesskette ist üblicherweise im einstelligen μm-Bereich. Dementsprechend ist die Werkzeugaufnahme in axialer und radialer Richtung mechanisch starr und unflexibel konzipiert. Diese Arbeit widmet sich der Zielsetzung, mit einem Werkzeugsystem für die schwingungsunterstützte Bearbeitung vor der eigentlichen Polierbearbeitung durch gröberes Korn glatte Oberflächen zu erzeugen. Entgegen klassischen Systemen, die mit hochfrequenten Schwingungen arbeiten, wurde ein Ansatz mit niederfrequenten Schwingungen erarbeitet. Zu diesem Zweck wurde ein gesamtes Werkzeughaltersystem auf Basis der HSK 63 Schnittstelle entwickelt. Den inhaltlichen Kern bildet der konzeptionelle Systementwurf, der sich thematisch in die mechanische, elektrische und thermische Konzeption aufgliedert. Die Amplitudenübertragung wird durch eine Biegemembrane, die eine dementsprechende axiale und radiale Nachgiebigkeit aufweist, realisiert. Für einen zuverlässigen Betrieb wurde hierbei auf die etablierte FKM-Methodik zurückgegriffen. Die Erzeugung der Amplitude geschieht durch einen angesteuerten piezoelektrischen Stapelaktuator. Hierbei wurde ein elektrisches System integriert, das eine Steuerung durch einen Frequenzgenerator in Kombination mit einem Bühnenverstärker ermöglicht. Als Schnittstelle für die Energieübertragung in das Werkzeugsystem wird eine berührungslose Induktionsschnittstelle integriert. Die im Betrieb entstehende thermische Abwärme wird durch ein passives Wärmeabfuhrsystem ohne aktive Kühlung abgeführt. Die abschließenden experimentellen Bearbeitungen zeigen vor allem bei niedrigen Prozessgeschwindigkeiten einen positiven Effekt des entwickelten Systems auf die Rauheit der bearbeiteten Oberflächen. Im Gegenzug erweist sich die ultraschallbedingte oberflächliche Zerrüttung durch das beim Einschlag der hart gebundenen Körner entstehende Risssystem der hochfrequenten US-Bearbeitung als ein negativer Einflussfaktor auf die gemessene Rauheit der Oberfläche der Proben aus silikatischem Glas.The fine machining of brittle-hard materials such as ceramics or glass represents a technological and economic challenge. One difficulty here is achieving low roughness values in the manufacturing process chain. Several machining steps with an undefined cutting edge are usually necessary for this type of machining. Vibration-supported process variants, which belong to the hybrid manufacturing processes, are often used here. A typical form of a hybrid finishing process is vibration-assisted machining using the transverse circumferential surface with rotating pin-shaped tools. In this hybrid process, the vibration is realized by an additional relative movement in the direction of the rotation axis of the tool. Systems in the frequency range of up to 50 kHz have proven themselves for this type of machining. Tools with bonded grains below 15 μm grain size are used. The average grain diameter at the end of the process chain is usually in the single-digit μm range. Accordingly, the toolholder is designed to be mechanically rigid and inflexible in the axial and radial directions. This work is dedicated to the objective of producing smooth surfaces with a tool system for vibration-assisted machining before the actual polishing process using coarser grit. In contrast to conventional systems that work with high-frequency vibrations, an approach using low-frequency vibrations was developed. For this purpose, an entire toolholder system was developed based on the HSK 63 interface. The conceptual system design, which is divided thematically into mechanical, electrical and thermal design, forms the core of the content. The amplitude transmission is realized by a bending diaphragm, which has a corresponding axial and radial flexibility. The established FKM method was used to ensure reliable operation. The amplitude is generated by a controlled piezoelectric stack actuator. An electrical system was integrated that enables control by a frequency generator in combination with a stage amplifier. A non-contact induction interface is integrated as the interface for transferring energy to the tool system. The thermal waste heat generated during operation is dissipated by a passive heat dissipation system without active cooling. The final experimental machining processes show a positive effect of the developed system on the roughness of the machined surfaces, especially at low process speeds. On the other hand, the ultrasound-induced surface disruption caused by the crack system of the high-frequency US machining that occurs when the hard-bonded grains are impacted proves to be a negative influencing factor on the measured roughness of the surface of the silicate glass samples
Surface nanocratering by localized plasma expansion induced by slow highly charged ions
No full textIon beam technology provides a powerful means for surface modification and nanostructuring of materials. In this work, slow highly charged xenon ions were used to fabricate well-defined nanopits in thin polymethyl methacrylate (PMMA) films. The pit surface density scales linearly with the applied ion fluence, demonstrating that each structure originates from a single ion impact. The formation of these nanopits is interpreted within a plasma expansion framework, in which the potential energy of an individual highly charged ion creates a transient, localized plasma within a nanometric surface region. The subsequent plasma expansion ejects material and produces a shallow surface depression. Numerical solutions of the hydrodynamic equations for the plasma components yield expansion parameters that agree with the experimentally observed pit dimensions and aspect ratios, confirming the plausibility of the proposed mechanism
Porous SiOC microspheres obtained via photopolymerization-assisted solidification templating of emulsions
No full textPorous polysiloxane-derived SiOC microspheres were produced via photopolymerization-assisted solidification templating of preceramic polymer emulsions, demonstrated for four structure-directing solvents (cyclohexane, cyclooctane, l-menthol, camphene). Internal pore morphologies of microspheres correspond to those of the respective monolithic analogues. In addition to unidirectional solidification of emulsions, a novel method is introduced for selective solidification and photopolymerization of cyclooctane/polymer droplets within the liquid water phase, significantly improving process efficiency. Cryomicroscopy supported evaluation of solidification kinetics of oil/water phases. Stirring intensity was found to control microsphere size. For the stirred-tank setup, SiOC microspheres showed monomodal size distributions (d50 = 199 µm) and modal pore opening diameters of 5.2 µm. A proof-of-principle was delivered for implementation of this process in a continuous-flow solidification/photoreactor, providing a base for future upscaling. The open-porous SiOC microspheres are a promising materials concept for application in catalysis or adsorption
Resolving reaction dynamics on a single catalytic particle
No full textIn heterogeneous catalysis, metal nanoparticles serve as the active centers for a wide range of industrially important reactions. Their bonding to the support, together with their chemical composition and morphology, determines catalytic performance. Gaining a detailed understanding of these local properties and their interactions within multicomponent systems is thus crucial for the rational development of new catalysts. However, while catalytic activity and selectivity are typically assessed using ensemble-averaged measurements, experimental techniques that enable direct observation of catalytic processes on a single nanoparticle remain limited. Only a small number of methods allow in situ or operando visualization of catalytic reaction dynamics at the nanoscale [1]. Here, we introduce a microscopy-based approach that utilizes the apex of a metallic nanotip as a well-defined model system emulating the surface of a spherical catalytic nanoparticle (r < 20 nm) [2].
By imaging, and analyzing the spatio-temporal dynamics of hydrogen oxidation on Rh, we directly probe structure-activity relations, lateral interactions within individual particles, and the emergent cooperative behavior between active sites. From these experimental findings, the mechanisms underlying lateral communication were deduced and further elucidated through microkinetic simulations employing two-dimensional oscillator grids [2-5]. By systematically varying particle size and geometry, as well as external reaction parameters such as temperature and reactant partial pressures, distinct spatio-temporal reaction patterns can be selectively established and reversibly interconverted. This degree of tunable control over reaction dynamics at the nanoscale provides new opportunities for optimizing catalytic systems by revealing reaction phenomena that have remained inaccessible with conventional approaches.
References:
[1] C. Vogt, B. M. Weckhuysen, Nat. Rev. Chem. 2022, 6, 89.[2] J. Zeininger et al. ACS Catal. 2021, 11, 10020–10027. [3] Y. Suchorski, J. Zeininger, S. Buhr, M. Raab, M. Stöger-Pollach, J. Bernardi, H. Grönbeck, G. Rupprechter, Science 2021, 372, 1314–1318. [4] M. Raab, J. Zeininger, Y. Suchorski, A. Genest, C. Weigl, G. Rupprechter, Nat. Commun. 2023, 14, 7186. [5] M. Raab, J. Zeininger, Y. Suchorski, K. Tokuda, G. Rupprechter, Nat. Commun. 2023, 14, 736
Advantages of High-Current-Density Resonant-Tunnelling Diodes at sub-THz Frequencies
No full textWe experimentally demonstrate significantly higher radiated power of resonant-tunnelling-diode (RTD) oscillators with high-current-density RTDs at relatively-low sub-THz frequencies compared to RTDs with lower current density. The results confirm our former theoretical analysis and predictions. The demonstration is done with symmetrical-slot-antenna RTD oscillators. However, it confirms a more general trait: RTD oscillators with high-current-density RTDs are not only advantageous at higher frequencies, but they exhibit superior performance also in the low sub-THz frequency range
Challenges and Vulnerabilities of Female-Headed Households in Obtaining Affordable Housing in Urban Areas: A Systematic Review
No full textThis study explores the key challenges and vulnerabilities of Female-Headed Households (FHHs) in accessing affordable housing in urban areas worldwide. Besides, the study discusses the global experience of FHHs regarding access to affordable housing in the global south, particularly in the Ethiopian context. To this aim, 73 peer-reviewed papers published between 1 January 2014 and 30 February 2025 were analyzed. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach was employed to select studies. The findings of the papers were analyzed using thematic analysis, word clouds, and keyword bibliometric analysis. The results indicate that the key problems affecting FHHs’ access to affordable housing globally are high housing prices, inadequate supply of affordable housing, economic insecurity, policy gaps, gender inequality, and patriarchal and socio-cultural practices. All of these factors and their intersectionality have forced FHHs to various socio-economic and health problems, including homelessness, delayed marriage and childbearing, gender based violence, food insecurity, and physical and mental health problems. Improving the supply of affordable housing is crucial to address the financial stress of FHHs and enhance their livelihoods. Additionally, implementing gender-responsible housing policies and promoting gender inequality in education and job opportunities is vital to promote an inclusive and sustainable urban development