Technische Universität Dresden: Qucosa
Not a member yet
16344 research outputs found
Sort by
Exposure traced in daily life: improvements in ecologically assessed social and physical activity following exposure-based psychotherapy for anxiety disorders
Get PDFBackground: Although exposure-based cognitive-behavioral therapy for anxiety disorders has frequently been proven effective, only few studies examined whether it improves everyday behavioral outcomes such as social and physical activity.
Methods: 126 participants (85 patients with panic disorder, agoraphobia, social anxiety disorder, or specific phobias, and 41 controls without mental disorders) completed smartphone-based ambulatory ratings (activities, social interactions, mood, physical symptoms) and motion sensor-based indices of physical activity (steps, time spent moving, metabolic activity) at baseline, during, and after exposure-based treatment.
Results: Prior to treatment, patients showed reduced mood and physical activity relative to healthy controls. Over the course of therapy, mood ratings, interactions with strangers and indices of physical activity improved, while reported physical symptoms decreased. Overall results did not differ between patients with primary panic disorder/agoraphobia and social anxiety disorder. Higher depression scores at baseline were associated with larger changes in reported symptoms and mood ratings, but smaller changes in physical activity
Conclusions: Exposure-based treatment initiates increased physical activity, more frequent interaction with strangers, and improvements in everyday mood. The current approach provides objective and fine-graded pro cess and outcome measures that may help to further improve treatments and possibly reduce relapse
Optimization of wood-based process chains in small scale forestry in Eastern Africa: Book of Abstracts from a Symposium, 21 - 25 August 2017
Get PDFThe symposium “Optimization of wood-based process chains in Eastern Africa” linked research on wood product processing, from the tree grower in the remote rural to the final consumers and markets in the urban centers. Senior and junior researchers from distinguished institutions in Ethiopia, Tanzania, Uganda and Germany jointly participate, were inspiring and learning from each other. The symposium presented a platform to extend the well-established project cooperation with East African towards technological and engineering disciplines as well as energy economics. It served to further develop the just started, DAAD and BMBF-funded project WoodCluster, which was implemented by East African universities and the Institute of International Forestry and Forest Products at TU Dresden.
The overall objective of the symposium was to create an interdisciplinary network of scientists with contact to the private sector to further develop and upscale wood-based process chains in decentralized structures, for example based on small scale farm forest enterprises in Africa.:Preface 3
Contents 5
Session 1: Country specific situation analysis 6
Some insights in the wood sector of Ethiopia 6
Optimization of wood-based process chains in eastern Africa 6
Adaption of forest operations to local conditions and social needs 7
Sawmilling industry cluster analysis for sawn wood supply and demand in selected regions of Tanzania 8
Session 2: Innovative technologies for processing of plantation timber 8
Wood properties of fast-growing plantation timber and related processing strategies 8
Innovations in wood processing and in wood products 9
‘Appropriate’ Technology Options for Timber Production in Uganda’s Plantation Forests 10
Present needs and trends of the woodworking industry 10
Wood in best form: innovative construction materials 11
Browsing for small scale wood processing technology on the trade fair Ligna 11
Project proposal: Integrated Wood Processing Subsidiary 12
Session 3: Innovative technologies for small scale wood based energy systems 12
Pyrolysis of wood: process, technical aspects and efficiency 12
Sustainable Wood Based Energy for Households in Developing Countries: Considering Wood Pellet as a Viable Alternative Household Energy Source in Ethiopia 13
Combined heat-power-charcoal conversion for African rural households: Available advanced models 14
Changing perspectives of German international Cooperation on problems and solutions for wood/bio-mass based energy conversion systems in Africa 15
Analysis of a wood chip gasifier in a thermochemical test area 15
Small Scale Wood Gas Cogeneration: Why, when, where? 16
Session 4: Innovation and technology transfer 16
Upgrading forest cluster and forest value chains for regional development 16
Assessing sustainability of small and micro enterprises 17
Knowledge systems and knowledge transfer 18
Innovation and technology transfer 18
Conclusions 19
Contact details of participants 2
«Wer sind wir, wenn wir gestalten?»: Zur Ko-Konstitution von Rollenbildern im Design
Get PDFDESIGNING GOVERNANCE – POWER AND COMPLICITY:1 Einleitung
1.1 Forschungsfragen
1.2 Vorgehen
2 Stereotypen, Kreativität und das Entwerfen
3 Im Auftrag: Das Briefing
4 Selbstinitiiert oder im Auftrag Dritter?
5 Kuratieren und Kollaborieren
6 Werte aushandeln: creative Entrepreneurs
7 Fazít
ReferencesDefinitionen des Designs basieren meist auf mehr oder weniger expliziten Vorstellungen des Entwerfens und der Kreativität. Für die Selbst- und Fremdwahrnehmung von Designer:innen ist beides konstitutiv, ebenso die ökonomische Verankerung der Designpraxis. Anhand von Aufträgen aus dem kulturellen Sektor und der Neuausrichtung
der Designförderung auf Bundesebene, untersucht der Beitrag die Konstitution von Auto- und Heterostereotypen im Schweizer Design um die Jahrtausendwende. Der Fokus der Analyse liegt auf den als diskursive Praktiken definierten Portfolio und Briefing. Befragt wird, wie die Akteur:innen in Aushandlungsprozessen kokonstituieren, wer sie sind, wenn sie ‹gestalten›. Die Analyse basiert methodisch auf der Auto- und Heterostereotypenforschung. Obgleich im Designprozess unterschiedlich positioniert, sind Portfolio
und Briefing in ihrer jeweiligen Funktion Bestandteil der Ökonomisierung des Entwerfens als Teil einer umfassenden Ökonomisierung der Gesellschaft. Unterfütterten seit den 1990er Jahren die Begriffe Autorschaft und Kreativität kulturell geframte Auto- und Heterostereotypen im Design, so sahen sich Designer:innen in den Nullerjahren mit Rollenerwartungen des Creative Entrepreneurs konfrontiert. Zusammen mit dem Stereotyp des Kuratierens entstanden so zwei neue Rollenbilder. Als gemeinsames Ziel definieren die in der Ko-Konstitution verbundenen Akteur:innen Distinktion mittels kreativer Neuheit.:1 Einleitung
1.1 Forschungsfragen
1.2 Vorgehen
2 Stereotypen, Kreativität und das Entwerfen
3 Im Auftrag: Das Briefing
4 Selbstinitiiert oder im Auftrag Dritter?
5 Kuratieren und Kollaborieren
6 Werte aushandeln: creative Entrepreneurs
7 Fazít
Reference
Taking design’s impact for a walk A roving panel in the Roterwald
Get PDFIMPACT AND MEASUREMENT – MANAGING RISK?:1 Introduction
2 The forest as a speculative device
2.1 You at risk: Measuring the Measurement
2.2 Other paths
2.3 Design´s afterlife
2.4 Going astray
2.5 Measuring impact with blurred glasses
2.6 Critical junctions and shortcuts
2.7 What goes around comes around
Acknowledgements
ReferencesFacing the complexity of conditions and relations where design performs, it has become increasingly challenging to measure and assess its desired impact. Termed a middle culture (van Winkel, 2009) between production and consumption, understandings of design often range between a heuristic drive to contribute to positive change in the world and a profile neurosis worried about finding a place in a world that may not recognise the profession’s relevance for maintaining existential infrastructures. A profession that – despite its high hopes for making the world a better place – is often being blamed for its complicity with economic-political systems that exploit resources and cause environmental damage. While an awareness of the wickedness of such problems has certainly been raised, alternatives to the impact paradigm are rarely explored. What effects does design aim for? Which assessment criteria and alternative evaluation methods could open alternative perspectives to notorious dichotomies of failure vs success, impact vs side-effect, optimisation vs obsolescence? [from the Introduction]:1 Introduction
2 The forest as a speculative device
2.1 You at risk: Measuring the Measurement
2.2 Other paths
2.3 Design´s afterlife
2.4 Going astray
2.5 Measuring impact with blurred glasses
2.6 Critical junctions and shortcuts
2.7 What goes around comes around
Acknowledgements
Reference
The Ecological Self: Exploring Relational Ontologies through Design
Get PDFSHIFTING PERSPEKTIVES – EXPLORING THE UNKOWN:1 Introduction and context
1.1 From human-centered to planetary-centered design
1.2 Theorising the more-than-human: Nature-Culture Models
1.3 The ontological dimension of design
1.4 The epistemiligical body
2 Practicing the debate
2.1 The Body as a resource
2.2 Humans as Humus
3 Conclusion
ReferencesThe paper questions the ontological separation of humans and nature on which the classical understanding of design is based and presents nature-culture models as an alternative in the context of global challenges such as the climate crisis. These models rest on relational ontologies and emphasise the entanglements and interdependencies
of all human and non-human actors. To explore these entanglements, the human body, in both its material and experiential dimensions, is emphasised as an epistemological source. Using examples of Rockström’s planetary boundaries model, the paper shows how humans, their bodies and their actions are connected to the environment
and ecological cycles and how they themselves can serve as a resource and regenerative link in ecological networks. Following the concept of relational ontologies, a new paradigm for design that recognises these ecological relationships, and the interdependence of humans and nature is explored through an embodied approach.:1 Introduction and context
1.1 From human-centered to planetary-centered design
1.2 Theorising the more-than-human: Nature-Culture Models
1.3 The ontological dimension of design
1.4 The epistemiligical body
2 Practicing the debate
2.1 The Body as a resource
2.2 Humans as Humus
3 Conclusion
Reference
Medien*ökologische Gestaltungsprinzipien für eine bio*inklusive Lebensraumgestaltung
Get PDFSHIFTING PERSPEKTIVES – EXPLORING THE UNKOWN:Einleitung
2 Medien*ökologisches Sensorium & Panorama
2.1 Medien*ökologisches Panorama: Umsetzung
2.2 Medien*ökologisches Panorama: Reflexionen und Ableitungen
3 Bio*inklusive Gestaltungsansätze
3.1 Bio*inklusive Gestaltungsansätze Umsetzungen
3.2 Bio*inklusive Gestaltungsansätze: Reflexionen und Ableitungen
4 Öko*soziale Lokalmedien
4.1 Wildcam TV: Umsetzung
4.2 Wildcam TV: Reflexionen und Ableitungen
Synthese
ReferenzenIn der Ökologie ist jedes menschliche Eingreifen ein Wagnis mit unvorhersehbaren Risiken. Ein naives Sichselbstüberlassen der ‹Natur› ist in postindustriell zersiedelten Kulturlandschaften des Anthropozäns allerdings auch keine Lösung. Eine nachhaltige Transformation menschlich geprägter (Stadt-)Landschaften, Architekturen
und Lebensweisen erfordert nachvollziehbare Mittel nicht nur zur Inklusion menschlicher Anspruchsgruppen, sondern auch der Belange anderer Lebewesen, des Terrains und des Planeten, ohne die bisherigen patriarchalen und extraktivistischen Praktiken zu reproduzieren. Ein nicht-reduktiver Umgang mit der Komplexität von ‹wicked problems›
kann in der Auseinandersetzung mit der biologischen Ökologie erlernt werden. Gestaltungsanspruch und -verfahren orientieren sich anstelle des Ingenieurwesens am Leitbild des Gärtnerns und der Landschaftspflege (Schwarz 2019). Wir plädieren für einen interdisziplinären, iterativen und kontextsensitiven Ansatz. Durch empirische Verbindungen von Analyse und Design sowie einen gemeinschaftlichen Lern- und Bildungsprozess soll Wirkung erreicht, evaluiert und vermittelt werden. Ein ökologisches Verständnis weltlicher Zusammenhänge liesse sich so konkret in bio*inklusive Gestaltungsformen zukünftiger mehr-als-menschlicher Mitwelten überführen.:Einleitung
2 Medien*ökologisches Sensorium & Panorama
2.1 Medien*ökologisches Panorama: Umsetzung
2.2 Medien*ökologisches Panorama: Reflexionen und Ableitungen
3 Bio*inklusive Gestaltungsansätze
3.1 Bio*inklusive Gestaltungsansätze Umsetzungen
3.2 Bio*inklusive Gestaltungsansätze: Reflexionen und Ableitungen
4 Öko*soziale Lokalmedien
4.1 Wildcam TV: Umsetzung
4.2 Wildcam TV: Reflexionen und Ableitungen
Synthese
Referenze
Process Engineering and Radiochemical Development on the Cyclotron-based Production of Theranostic Radiometals
Get PDFThe work presented here aims to increase the availability of non-standard radionuclides for nuclear medicine purposes. Alternative production routes for four radiometallic nuclides, including a novel radiometal, were investigated and optimized. The production of medically relevant radionuclides, namely 61Cu, 67Cu, 67Ga and 133La was investigated on the basis of the higher proton energy of up to 30 MeV that the existing cyclotron makes possible
Tailoring Phonon Polaritons in 2D van-der-Waals Materials
Get PDFTailoring and precisely controlling the propagation of confined light precisely at the nanometer-length scale is an ubiquitous requirement for the realization of integrated optics and, hence, a major goal of the current research in nano-optics. Phonon polaritons (PhPs) - quasi-particles formed by the interaction of light with excitations of the crystal lattice - propagating in thin layers of van-der-Waals (vdW) materials are key to solve this challenge, as they intrinsically offer high confinement of light coupled with low losses, as well as an inherent directional energy transport profiting from the lattice anisotropy of the polariton-hosting material. Furthermore, their strong interaction with surrounding media due to their high surface-to-volume ratio allows for tuning of their wavelengths, shape of wavefront and type of propagation, e.g. via changing the substrate permittivity or stacking multiple layers of polariton-hosting vdW materials under defined twist angles (twistoptics). However, due to the limited access to light sources and detectors operating at frequencies in the so-called THz gap between 0.1 and 10 THz, the research so far had focused to the mid-infrared (MIR) frequency range, omitting the reststrahlen bands of numerous materials spectrally located at or in the THz range.
The present work focuses precisely on such PhPs spectrally located at THz frequencies and the tailoring of their propagation behavior. For that purpose, the vdW materials α-molybdenum trioxide (α-MoO3) and α-germanium monosulfide (α-GeS), featuring THz reststrahlen bands between 7.85 to 11.8 THz and 6.06 to 9.70 THz, respectively, have been employed as polariton-hosting materials. Specifically, within the framework of this thesis, the manipulation of the PhP propagation of THz PhPs is achieved via two approaches: First, the deposition of the two polariton-hosting materials onto different substrate materials, including three isotropic materials (Si, SiO2, and Ge) featuring different dielectric responses, and the highly anisotropic β-gallium oxide (bGO) under different twist angles. By doing so the tuning of the PhP wavelengths and the directionality of their propagation as well as the observation of unidirectional ray-like PhPs is achieved. Second, the stacking of two flakes of the polariton-hosting materials to homo- and heterostacks. This extension of the concept of twistoptics from the MIR frequency range to the THz regime enables the tuning of the THz PhP propagation between in-plane hyperbolic and in-plane elliptic, including the first observation of canalized THz PhPs.
All studies presented in this work are conducted by combining theoretical simulations, including analytical transfer-matrix calculations and numerical full-wave approaches, with experimental measurements, performed with scattering-type scanning near-field optical microscopy (s-SNOM) utilizing the free-electron laser FELBE (Dresden, Germany) as the tunable THz light source. This unique combination allows for the measurement of the optical properties of materials at frequencies between 1.2 and 60 THz, covering a large part of the THz gap, with a lateral resolution down to 20 nm, thus enabling the real-space visualization of the target PhP propagations at the 2D surfaces.
Overall, these studies explore different methods to tune the propagation of THz PhPs, extending the frequency range of tailoring polaritons and thus contributing to the development in the booming field of THz nano-optics.:1 Introduction 1
2 Fundamentals 5
2.1 Phonon Polaritons 5
2.1.1 Phonons and their Interaction with Light 6
2.1.2 Types of Phonon Polaritons 7
2.1.3 Theoretical Models Describing Phonon Polaritons 13
2.2 Van-der-Waals (vdW) Materials 18
2.2.1 Properties of vdW Materials 19
2.2.2 Twistoptics 20
2.3 Scattering-type Scanning Near-field Optical Microscopy (s-SNOM) 22
2.3.1 Historic Development of SNOM 23
2.3.2 Scanning Force Microscopy (SFM) 24
2.3.3 Decoupling Near- and Far-Field in s-SNOM 27
2.3.4 Examples of s-SNOM applications 31
3 Setup and Materials 33
3.1 Experimental Setup 33
3.1.1 s-SNOM instrument neaSNOM 34
3.1.2 Free-Electron Laser FELBE 39
3.1.3 Light Detection 42
3.1.4 Utilized Setup Parameters 44
3.2 Data Acquisition 44
3.2.1 Data Processing 45
3.2.2 Extraction of Polariton Parameters 50
3.2.3 2D Fast Fourier Transformation with 'Zero Padding' 52
3.3 Materials 53
3.3.1 α-Molybdenum Trioxide (α-MoO3) 53
3.3.2 α-Germanium Monosulfide (α-GeS) 57
3.3.3 β-Gallium Oxide (β-Ga2O3) 61
3.3.4 Isotropic Substrates 64
3.4 Sample Preparation 65
3.4.1 Exfoliating Layers of vdW Materials 65
3.4.2 Pre-Characterization 67
3.4.3 Sample Structuring for the PhP Propagation-Shape Imaging 70
4 Results I: Tuning Phonon Polaritons in vdW Single Layers via Substrates 75
4.1 General Theoretical Considerations 76
4.1.1 Tuning via an Isotropic Substrate 76
4.1.2 Tuning via an Anisotropic Substrate 79
4.2 Tuning Hyperbolic Phonon Polaritons in Single-Layers
of α-Molybdenum Trioxide 82
4.2.1 Impact of the Substrate Permittivity vs. Layer Thickness 82
4.2.2 Enhanced Tuning via Substrate Anisotropy: Utilizing β-Gallium Oxide as Substrate 86
4.3 Tuning Phonon Polaritons in Single-Layers of α-Germanium Monosulfide 94
4.3.1 The Complex Dispersion of α-Germanium Monosulfide 95
4.3.2 Tuning the Dispersion Splitting via the Substrate Permittivity 99
4.3.3 Impact of the Substrate Permittivity on the In-Plane Propagation Shape 104
4.3.4 Analyzing the Origin of the Dispersion Splitting 109
4.4 Chapter Conclusion 115
5 Results II: Tuning Phonon Polaritons in Twisted Bi-Layer Stacks 117
5.1 Twisted Bilayer α-Molybdenum Trioxide at THz frequencies 117
5.1.1 Theoretical Considerations 118
5.1.2 Experimental Observations 120
5.1.3 Quantitative Characterization of the Measured THz Phonon Polaritons 126
5.1.4 Canalization of Hyperbolic Phonon Polaritons 129
5.2 Heterostacks made up from α-Germanium Monosulfide on α-Molybdenum Trioxide 130
5.2.1 Preliminary Experimental Observations 131
5.2.2 Theoretical Predictions 134
5.3 Chapter Conclusion 138
6 Final Conclusion 141
Appendices 145
A1 Comprehensive Overview of the s-SNOM Performance for Different Experimental Settings 147
A1.1 Extracted Signal-to-Noise Ratios 148
A1.2 Images of the Performed Retracts 156
A1.3 Images of the Performed Scans 162
A2 Additional Measurements of Twisted α-MoO3 Homostacks 163
Bibliography 165
Own Publications 17
Fully refractive telecentric f-theta microscope based on adaptive elements for 3D raster scanning of biological tissues
Get PDFVarious techniques in microscopy are based on point-wise acquisition, which provides advantages in acquiring sectioned images, for example in confocal or two-photon microscopy. The advantages come along with the need to perform three-dimensional scanning, which is often realized by mechanical movement achieved by stage-scanning or piezo-based scanning in the axial direction. Lateral scanning often employs galvo-mirrors, leading to a reflective setup and hence to a folded beam path. In this paper, we introduce a fully refractive microscope capable of three-dimensional scanning, which employs the combination of an adaptive lens, an adaptive prism, and a tailored telecentric f-theta objective. Our results show that this microscope is capable to perform flexible three-dimensional scanning, with low scan-induced aberrations, at a uniform resolution over a large tuning range of X = Y = 6300 µm and Z = 480 µm with only transmissive components. We demonstrate the capabilities at the example of volumetric measurements on the transgenic fluorescence of the thyroid of a zebrafish embryo and mixed pollen grains. This is the first step towards flexible aberration-free volumetric smart microscopy of three-dimensional samples like embryos and organoids, which could be exploited for the demands in both lateral and axial dimensions in biomedical samples without compromising image qualit