Refine
Year of publication
- 2024 (47)
- 2023 (167)
- 2022 (219)
- 2021 (218)
- 2020 (218)
- 2019 (300)
- 2018 (248)
- 2017 (254)
- 2016 (251)
- 2015 (284)
- 2014 (265)
- 2013 (283)
- 2012 (291)
- 2011 (305)
- 2010 (317)
- 2009 (332)
- 2008 (289)
- 2007 (271)
- 2006 (276)
- 2005 (263)
- 2004 (286)
- 2003 (218)
- 2002 (232)
- 2001 (210)
- 2000 (234)
- 1999 (232)
- 1998 (236)
- 1997 (214)
- 1996 (200)
- 1995 (192)
- 1994 (174)
- 1993 (154)
- 1992 (144)
- 1991 (100)
- 1990 (108)
- 1989 (110)
- 1988 (103)
- 1987 (105)
- 1986 (81)
- 1985 (83)
- 1984 (75)
- 1983 (70)
- 1982 (57)
- 1981 (54)
- 1980 (61)
- 1979 (58)
- 1978 (52)
- 1977 (32)
- 1976 (30)
- 1975 (28)
- 1974 (17)
- 1973 (12)
- 1972 (17)
- 1971 (11)
- 1970 (2)
- 1969 (2)
- 1968 (2)
- 1967 (1)
- 1963 (1)
Document Type
- Article (5464)
- Conference Proceeding (1393)
- Book (1056)
- Part of a Book (544)
- Patent (172)
- Bachelor Thesis (156)
- Report (81)
- Doctoral Thesis (78)
- Other (68)
- Contribution to a Periodical (19)
- Master's Thesis (17)
- Review (17)
- Working Paper (8)
- Talk (5)
- Habilitation (4)
- Preprint (4)
- Diploma Thesis (3)
- Poster (3)
- Part of Periodical (2)
- Examination Thesis (1)
Language
Has Fulltext
- no (9096) (remove)
Keywords
- Corporate Design (9)
- Illustration (9)
- Erscheinungsbild (8)
- Gamification (8)
- Nachhaltigkeit (8)
- Redesign (7)
- Animation (6)
- Datenschutz (6)
- Digitalisierung (6)
- avalanche (6)
- App (5)
- Earthquake (5)
- Editorial (5)
- Enterprise Architecture (5)
- Fotografie (5)
- Geschichte (5)
- MINLP (5)
- solar sail (5)
- Aktionskunst (4)
- Design (4)
Institute
- Fachbereich Medizintechnik und Technomathematik (1907)
- Fachbereich Elektrotechnik und Informationstechnik (1116)
- Fachbereich Wirtschaftswissenschaften (1100)
- Fachbereich Energietechnik (1056)
- Fachbereich Chemie und Biotechnologie (829)
- Fachbereich Maschinenbau und Mechatronik (799)
- Fachbereich Luft- und Raumfahrttechnik (749)
- Fachbereich Bauingenieurwesen (658)
- IfB - Institut für Bioengineering (623)
- INB - Institut für Nano- und Biotechnologien (584)
- Solar-Institut Jülich (334)
- Fachbereich Gestaltung (333)
- Fachbereich Architektur (161)
- ECSM European Center for Sustainable Mobility (106)
- MASKOR Institut für Mobile Autonome Systeme und Kognitive Robotik (66)
- Nowum-Energy (64)
- ZHQ - Bereich Hochschuldidaktik und Evaluation (62)
- Institut fuer Angewandte Polymerchemie (32)
- Sonstiges (24)
- IBB - Institut für Baustoffe und Baukonstruktionen (21)
There is common agreement within the scientific community that in order to understand our local galactic environment it will be necessary to send a spacecraft into the region beyond the solar wind termination shock. Considering distances of 200 AU for a new mission, one needs a spacecraft traveling at a speed of close to 10 AU/yr in order to keep the mission duration in the range of less than 25 yrs, a transfer time postulated by European Space Agency (ESA). Two propulsion options for the mission have been proposed and discussed so far: the solar sail propulsion and the ballistic/radioisotope-electric propulsion (REP). As a further alternative, we here investigate a combination of solar-electric propulsion (SEP) and REP. The SEP stage consists of six 22-cms diameter RIT-22 ion thrusters working with a high specific impulse of 7377 s corresponding to a positive grid voltage of 5 kV. Solar power of 53 kW at begin of mission (BOM) is provided by a lightweight solar array.
Vitamin D plays an essential role in calcium and inorganic phosphate (Pi) homeostasis, maintaining their optimal levels to assure adequate bone mineralization. Vitamin D, as calcitriol (1,25(OH)2D), not only increases intestinal calcium and phosphate absorption but also facilitates their renal reabsorption, leading to elevated serum calcium and phosphate levels. The interaction of 1,25(OH)2D with its receptor (VDR) increases the efficiency of intestinal absorption of calcium to 30–40% and phosphate to nearly 80%. Serum phosphate levels can also influence 1,25 (OH)2D and fibroblast growth factor 23 (FGF23) levels, i.e., higher phosphate concentrations suppress vitamin D activation and stimulate parathyroid hormone (PTH) release, while a high FGF23 serum level leads to reduced vitamin D synthesis. In the vitamin D-deficient state, the intestinal calcium absorption decreases and the secretion of PTH increases, which in turn causes the stimulation of 1,25(OH)2D production, resulting in excessive urinary phosphate loss. Maintenance of phosphate homeostasis is essential as hyperphosphatemia is a risk factor of cardiovascular calcification, chronic kidney diseases (CKD), and premature aging, while hypophosphatemia is usually associated with rickets and osteomalacia. This chapter elaborates on the possible interactions between vitamin D and phosphate in health and disease.
Kinder im Kontext von medizinischen Einrichtungen.
Kinder sind keine kleinen Erwachsenen und erfordern einen auf sie angepassten Zugang zu medizinischen Behandlungsabläufen. Das Konzept basiert auf dem Gestaltungsprinzip des „Child Centered Design“ mit Befragungen von Experten der Pädiatrie und Forschung sowie mit enger Zusammenarbeit mit Kindern.
Entstanden ist ein Produkt welches Skepsis und Angst junger Patienten im Alter von 6 bis 14 Jahren bei stationären Aufenthalten in Krankenhäusern mindert und ihren Heilungsprozess positiv unterstützt. Unter Einbezug von digitalen Möglichkeiten wie Augmented Reality erklärt „ViU“, ein Krankenhaus-Companion in Eulen-Optik, den kleinen Patienten Funktionen und das Wirken verschiedenster medizinischer Geräte und Behandlungen. So wird nicht nur der Rate an Traumata durch Krankenhausaufenthalte bei Kindern entgegengewirkt, sondern auch das Krankenhauspersonal im Umgang mit Kindern im Klinikalltag entlastet.
Mit dem Projekt wird sich dem Problem der weltweiten Lebensmittelverschwendung angenommen und versucht Abfälle in Privathaushalten primär industrialisierter Staaten zu reduzieren. Mit jährlich 1,3 Milliarden Tonnen landet circa ein Drittel aller weltweit produzierten Lebensmittel im Müll. Einen Großteil dieser Abfälle ist vermeidbar, besonders dort, wo man im Überfluss lebt.
Das konzipierte Möbelstück soll die Lagerungsmöglichkeiten des Nutzers optimieren und somit für die Wertschätzung von Lebensmitteln sensibilisieren. Für das Möbelstück werden ausschließlich natürliche Materialien verwendet, welche in ihrer Charakteristik optimal zum Funktionsumfang passen, der für die Lagerung benötigt wird. Das Material Terracotta ermöglicht es, mittels Verdunstungskühlung stromlos Gemüse kalt zu halten. Antibakterielles Holz tötet schädliche Bakterien ab. Die Konstruktion ermöglicht somit eine fachgerechte Lebensmittelagerung und ermöglicht sowohl sehr flexible Nutzung, wie auch leichte Reparatur.
Living product: ein Ansatz, lebendige Organismen mit einem Produkt zu vereinen und nutzbar zu machen
(2021)
Diese Arbeit setzt sich mit der Frage auseinander, in welcher Form sich lebendige Organismen – hier insbesondere Pilze - in die Produktwelt integrieren lassen. In welcher Art und Weise beeinflusst ein Organismus das Produkterlebnis?
Im Rahmen dieser Arbeit sind vier verschiedene Produkte entstanden, die die Stärken des Materials Myzelium demonstrieren. Myzelium bezeichnet das sehr dichte Wurzelnetzwerk eines Pilzes. Dieses lebendige Netzwerk kann dazu genutzt werden, um organische Stoffe miteinander zu verwachsen und somit Formen entstehen zu lassen. Die so entstandenen Produkte sind in eine Konzeptumgebung eingebettet, in der der Verbrauchende die Natur durch naturnähere Produkte (Form, Material und gewachsene Strukturen) neu erlebt.
Gezeigt wird ein Packaging für Einmachgläser, ein Kressebeet, ein Wandregal und ein Teelicht.
Solar sailcraft provide a wide range of opportunities for high-energy low-cost missions. To date, most mission studies require a rather demanding performance that will not be realized by solar sailcraft of the first generation.
However, even with solar sailcraft of moderate performance, scientifically relevant missions are feasible. This is demonstrated with a Near Earth Asteroid sample return mission and various planetary rendezvous missions.
Solar sails are propelled in space by reflecting solar photons off large mirroring surfaces, thereby transforming the momentum of the photons into a propulsive force. This innovative concept for low-thrust space propulsion works without any propellant and thus provides a wide range of opportunities for highenergy low-cost missions. Offering an efficient way of propulsion, solar sailcraft could close a gap in transportation options for highly demanding exploration missions within our solar system and even beyond. On December 17th, 1999, a significant step was made towards the realization of this technology: a lightweight solar sail structure with an area of 20 m × 20 m was successfully deployed on ground in a large facility at the German Aerospace Center (DLR) at Cologne. The deployment from a package of 60 cm × 60 cm × 65 cm with a total mass of less than 35 kg was achieved using four extremely light-weight carbon fiber reinforced plastics (CFRP) booms with a specific mass of 100 g/m. The paper briefly reviews the basic principles of solar sails as well as the technical concept and its realization in the ground demonstration experiment, performed in close cooperation between DLR and ESA. Next possible steps are outlined. They could comprise the in-orbit demonstration of the sail deployment on the upper stage of a low-cost rocket and the verification of the propulsion concept by an autonomous and free flying solar sail in the frame of a scientific mission. It is expected that the present design could be extended to sail sizes of about (40 m)2 up to even (70 m)2 without significant mass penalty. With these areas, the maximum achievable thrust at 1 AU would range between 10 and 40 mN – comparable to some electric thrusters. Such prototype sails with a mass between 50 and 150 kg plus a micro-spacecraft of 50 to 250 kg would have a maximum acceleration in the order of 0.1 mm/s2 at 1 AU, corresponding to a maximum ∆V-capability of about 3 km/s per year. Two near/medium-term mission examples to a near-Earth asteroid (NEA) will be discussed: a rendezvous mission
and a sample return mission.
Solar sails are large and lightweight reflective structures that are propelled by solar radiation pressure. This chapter covers their orbital and attitude dynamics and control. First, the advantages and limitations of solar sails are discussed and their history and development status is outlined. Because the dynamics of solar sails is governed by the (thermo-)optical properties of the sail film, the basic solar radiation pressure force models have to be described and compared before parameters to measure solar sail performance can be defined. The next part covers the orbital dynamics of solar sails for heliocentric motion, planetocentric motion, and motion at Lagrangian equilibrium points. Afterwards, some advanced solar radiation pressure force models are described, which allow to quantify the thrust force on solar sails of arbitrary shape, the effects of temperature, of light incidence angle, of surface roughness, and the effects of optical degradation of the sail film in the space environment. The orbital motion of a solar sail is strongly coupled to its rotational motion, so that the attitude control of these soft and flexible structures is very challenging, especially for planetocentric orbits that require fast attitude maneuvers. Finally, some potential attitude control methods are sketched and selection criteria are given.
Unsteady shallow meandering flows in rectangular reservoirs: a modal analysis of URANS modelling
(2022)
Shallow flows are common in natural and human-made environments. Even for simple rectangular shallow reservoirs, recent laboratory experiments show that the developing flow fields are particularly complex, involving large-scale turbulent structures. For specific combinations of reservoir size and hydraulic conditions, a meandering jet can be observed. While some aspects of this pseudo-2D flow pattern can be reproduced using a 2D numerical model, new 3D simulations, based on the unsteady Reynolds-Averaged Navier-Stokes equations, show consistent advantages as presented herein. A Proper Orthogonal Decomposition was used to characterize the four most energetic modes of the meandering jet at the free surface level, allowing comparison against experimental data and 2D (depth-averaged) numerical results. Three different isotropic eddy viscosity models (RNG k-ε, k-ε, k-ω) were tested. The 3D models accurately predicted the frequency of the modes, whereas the amplitudes of the modes and associated energy were damped for the friction-dominant cases and augmented for non-frictional ones. The performance of the three turbulence models remained essentially similar, with slightly better predictions by RNG k-ε model in the case with the highest Reynolds number. Finally, the Q-criterion was used to identify vortices and study their dynamics, assisting on the identification of the differences between: i) the three-dimensional phenomenon (here reproduced), ii) its two-dimensional footprint in the free surface (experimental observations) and iii) the depth-averaged case (represented by 2D models).