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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).
Near-Earth asteroid (NEA) 99942 Apophis provides a typical example for the evolution of asteroid orbits that lead to Earth-impacts after a close Earth-encounter that results in a resonant return. Apophis will have a close Earth-encounter in 2029 with potential very close subsequent Earth-encounters (or even an impact) in 2036 or later, depending on whether it passes through one of several less than 1 km-sized gravitational keyholes during its 2029-encounter. A pre-2029 kinetic impact is a very favorable option to nudge the asteroid out of a keyhole. The highest impact velocity and thus deflection can be achieved from a trajectory that is retrograde to Apophis orbit. With a chemical or electric propulsion system, however, many gravity assists and thus a long time is required to achieve this. We show in this paper that the solar sail might be the better propulsion system for such a mission: a solar sail Kinetic Energy Impactor (KEI) spacecraft could impact Apophis from a retrograde trajectory with a very high relative velocity (75-80 km/s) during one of its perihelion passages. The spacecraft consists of a 160 m × 160 m, 168 kg solar sail assembly and a 150 kg impactor. Although conventional spacecraft can also achieve the required minimum deflection of 1 km for this approx. 320 m-sized object from a prograde trajectory, our solar sail KEI concept also allows the deflection of larger objects. For a launch in 2020, we also show that, even after Apophis has flown through one of the gravitational keyholes in 2029, the solar sail KEI concept is still feasible to prevent Apophis from impacting the Earth, but many KEIs would be required for consecutive impacts to increase the total Earth-miss distance to a safe value
Virgin passive colon biomechanics and a literature review of active contraction constitutive models
(2022)
The objective of this paper is to present our findings on the biomechanical aspects of the virgin passive anisotropic hyperelasticity of the porcine colon based on equibiaxial tensile experiments. Firstly, the characterization of the intestine tissues is discussed for a nearly incompressible hyperelastic fiber-reinforced Holzapfel–Gasser–Ogden constitutive model in virgin passive loading conditions. The stability of the evaluated material parameters is checked for the polyconvexity of the adopted strain energy function using positive eigenvalue constraints of the Hessian matrix with MATLAB. The constitutive material description of the intestine with two collagen fibers in the submucosal and muscular layer each has been implemented in the FORTRAN platform of the commercial finite element software LS-DYNA, and two equibiaxial tensile simulations are presented to validate the results with the optical strain images obtained from the experiments. Furthermore, this paper also reviews the existing models of the active smooth muscle cells, but these models have not been computationally studied here. The review part shows that the constitutive models originally developed for the active contraction of skeletal muscle based on Hill’s three-element model, Murphy’s four-state cross-bridge chemical kinetic model and Huxley’s sliding-filament hypothesis, which are mainly used for arteries, are appropriate for numerical contraction numerical analysis of the large intestine.
The planned coal phase-out in Germany by 2038 will lead to the dismantling of power plants with a total capacity of approx. 30 GW. A possible further use of these assets is the conversion of the power plants to thermal storage power plants; the use of these power plants on the day-ahead market is considerably limited by their technical parameters. In this paper, the influence of the technical boundary conditions on the operating times of these storage facilities is presented. For this purpose, the storage power plants were described as an MILP problem and two price curves, one from 2015 with a relatively low renewable penetration (33 %) and one from 2020 with a high renewable energy penetration (51 %) are compared. The operating times were examined as a function of the technical parameters and the critical influencing factors were investigated. The thermal storage power plant operation duration and the energy shifted with the price curve of 2020
increases by more than 25 % compared to 2015.
Konzeption eines Flagship-Stores mit Wohlfühl- und Erlebnis-Spaces
Die Bedürfnisse von Besuchern und Kunden eines Geschäfts haben sich über die letzten Jahre stark verändert. Sie möchten das ihr Kauf zum Erlebnis wird. Auf Basis dieser Erkenntnis wurde im Rahmen dieser Arbeit zusammen mit den Produkten des Weltmarktführers für Teichtechnik und Aquaristik „OASE – Living Water“ ein Storekonzept geschaffen. Dieses verbindet den Verkaufsraum mit unterschiedlichen Erlebniswelten, welche auf die jeweilig ausgestellte Produktkategorie abgestimmt sind. Zusätzlich eröffnet ein diverser und aufregend gestalteter Gartenbereich der zum Entspannen und Verweilen einlädt. Der herausstechende Aspekt des Konzepts ist, dass die Produkte sowohl als reines Produkt, als auch in verbauter Version in Aktion zu sehen sind. Auf diese Art bietet die Marke „OASE – Living Water“ ein neues Kauf-Erlebnis an.
Experimental and numerical investigation on the effect of pressure on micromix hydrogen combustion
(2021)
The micromix (MMX) combustion concept is a DLN gas turbine combustion technology designed for high hydrogen content fuels. Multiple non-premixed miniaturized flames based on jet in cross-flow (JICF) are inherently safe against flashback and ensure a stable operation in various operative conditions.
The objective of this paper is to investigate the influence of pressure on the micromix flame with focus on the flame initiation point and the NOx emissions. A numerical model based on a steady RANS approach and the Complex Chemistry model with relevant reactions of the GRI 3.0 mechanism is used to predict the reactive flow and NOx emissions at various pressure conditions. Regarding the turbulence-chemical interaction, the Laminar Flame Concept (LFC) and the Eddy Dissipation Concept (EDC) are compared. The numerical results are validated against experimental results that have been acquired at a high pressure test facility for industrial can-type gas turbine combustors with regard to flame initiation and NOx emissions.
The numerical approach is adequate to predict the flame initiation point and NOx emission trends. Interestingly, the flame shifts its initiation point during the pressure increase in upstream direction, whereby the flame attachment shifts from anchoring behind a downstream located bluff body towards anchoring directly at the hydrogen jet. The LFC predicts this change and the NOx emissions more accurately than the EDC. The resulting NOx correlation regarding the pressure is similar to a non-premixed type combustion configuration.
Kawasaki Heavy Industries, LTD. (KHI) has research and development projects for a future hydrogen society. These projects comprise the complete hydrogen cycle, including the production of hydrogen gas, the refinement and liquefaction for transportation and storage, and finally the utilization in a gas turbine for electricity and heat supply. Within the development of the hydrogen gas turbine, the key technology is stable and low NOx hydrogen combustion, namely the Dry Low NOx (DLN) hydrogen combustion.
KHI, Aachen University of Applied Science, and B&B-AGEMA have investigated the possibility of low NOx micro-mix hydrogen combustion and its application to an industrial gas turbine combustor. From 2014 to 2018, KHI developed a DLN hydrogen combustor for a 2MW class industrial gas turbine with the micro-mix technology. Thereby, the ignition performance, the flame stability for equivalent rotational speed, and higher load conditions were investigated. NOx emission values were kept about half of the Air Pollution Control Law in Japan: 84ppm (O2-15%). Hereby, the elementary combustor development was completed.
From May 2020, KHI started the engine demonstration operation by using an M1A-17 gas turbine with a co-generation system located in the hydrogen-fueled power generation plant in Kobe City, Japan. During the first engine demonstration tests, adjustments of engine starting and load control with fuel staging were investigated. On 21st May, the electrical power output reached 1,635 kW, which corresponds to 100% load (ambient temperature 20 °C), and thereby NOx emissions of 65 ppm (O2-15, 60 RH%) were verified. Here, for the first time, a DLN hydrogen-fueled gas turbine successfully generated power and heat.
This study investigates the influence of pressure on the temperature distribution of the micromix (MMX) hydrogen flame and the NOx emissions. A steady computational fluid dynamic (CFD) analysis is performed by simulating a reactive flow with a detailed chemical reaction model. The numerical analysis is validated based on experimental investigations. A quantitative correlation is parametrized based on the numerical results. We find, that the flame initiation point shifts with increasing pressure from anchoring behind a downstream located bluff body towards anchoring upstream at the hydrogen jet. The numerical NOx emissions trend regarding to a variation of pressure is in good agreement with the experimental results. The pressure has an impact on both, the residence time within the maximum temperature region and on the peak temperature itself. In conclusion, the numerical model proved to be adequate for future prototype design exploration studies targeting on improving the operating range.
Mit MULO wurde eine Serie multifunktionaler Objekte für den Wohnbereich entworfen. In Zeiten des Überangebots und des ständigen Wohnraumwechsels soll der Nutzer dieser Objekte mit einem modernen und schlichten Design unterstützt werden, das zu jedem Anlass passt. Die minimalistische Ästhetik mit hohem Komfort orientiert sich dabei an den Bedürfnissen des Endverbrauchers.
Als Verwandlungskünstler bereichert MULO jeden Wohnraum. Die gesamte Serie ist unter der Berücksichtigung der schnelllebigen und sich wandelnden Welt entworfen worden. Mit multifunktionalen Objekten ist das Produkt den flexiblen Anforderungen und Bedürfnissen des Menschen gewachsen. Die Bereiche Wohnen, Leben, Arbeiten, Schlafen und Entspannen werden durch das Sofa- , das Tisch- und das Keramik-System optimal abgedeckt. Durch die Verwendung von nachhaltigen und recycelbaren Materialien, setzt MULO ein kleines Statement und hinterlässt nachhaltig Eindruck.
Yocu ist ein Konzept für den Gesundheitssektor, dass unter der Betrachtung der relevanten Trends und der Researchergebnisse den Therapieansatz des „Schröpfen“ in einen neuen modernen Kontext setzt, dabei aber die Vorteile der traditionellen Heilkunst nicht außer Acht lässt. Es handelt sich um ein Therapieprodukt für fasziale Verklebungen und Muskel-Skelett-Erkrankungen.
Mit Yocu bekommen Nutzer die Möglichkeit, sich selbst erfolgreich präventiv oder bei Beschwerden zu behandeln. Das könnte nicht nur die körperliche Gesundheit fördern, sondern auch das Gespür für den eigenen Körper. Seine körperlichen Bedürfnisse besser einschätzen zu können und in der Lage zu sein, diese zu erfüllen, stellt das Ziel des Konzepts dar.
Mit dem gewählten „Healthtech“ Ansatz soll der Zugang zur Selbsttherapie für Laien ermöglicht werden. Zusätzlich könnte das Konzept die Arbeit für Physiotherapeut:innen und Fitnesstrainer:innen erleichtern. Durch die Symbiose eines elektronischen Therapieproduktes mit einer Anwendungsapp ist die Behandlung punktgenau steuerbar und basiert nicht mehr ausschließlich auf Gefühl oder Erfahrung. Durch die Einsicht aller wichtigen Parameter, wird das Verständnis der Therapiemethode gefördert und Vertrauen hinsichtlich des Produkts geschaffen.
KOMU entstand durch Analysieren der Veränderungen, die mit der Urbanisierung einhergehen - schnell schwindender Wohnraum, häufiges Umziehen und verschmolzene Raumnutzung.
KOMU ist ein modulares Regalsystem, das ermöglicht, problemlos aus denselben Bestandteilen immer wieder verschiedene Wohn- und Raumsituationen zu schaffen.
Das System ist komplett werkzeugfrei durch simples Ineinanderstecken aufzubauen. Weitere Add-Ons können über das gleiche Stecksystem in das Regal integriert werden, damit es perfekt an die Bedürfnisse des Kunden anpasst werden kann.
Durch klare Linien und eine cleane Designsprache fügt sich KOMU nahtlos in seine Umgebung ein und hilft, eine für den Kunden ideale Umgebung zu schaffen.
Ein Regal, das mitwächst - vielfältig und individuell.