Refine
Year of publication
- 2024 (111)
- 2023 (255)
- 2022 (301)
- 2021 (293)
- 2020 (241)
- 2019 (378)
- 2018 (259)
- 2017 (259)
- 2016 (277)
- 2015 (301)
- 2014 (301)
- 2013 (301)
- 2012 (332)
- 2011 (328)
- 2010 (342)
- 2009 (369)
- 2008 (311)
- 2007 (312)
- 2006 (330)
- 2005 (303)
- 2004 (323)
- 2003 (254)
- 2002 (250)
- 2001 (221)
- 2000 (245)
- 1999 (236)
- 1998 (242)
- 1997 (220)
- 1996 (202)
- 1995 (192)
- 1994 (174)
- 1993 (154)
- 1992 (144)
- 1991 (100)
- 1990 (108)
- 1989 (111)
- 1988 (104)
- 1987 (105)
- 1986 (81)
- 1985 (84)
- 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)
- 1925 (1)
Institute
- Fachbereich Medizintechnik und Technomathematik (2072)
- Fachbereich Elektrotechnik und Informationstechnik (1184)
- Fachbereich Wirtschaftswissenschaften (1158)
- Fachbereich Energietechnik (1115)
- Fachbereich Chemie und Biotechnologie (912)
- Fachbereich Maschinenbau und Mechatronik (868)
- Fachbereich Luft- und Raumfahrttechnik (797)
- Fachbereich Bauingenieurwesen (711)
- IfB - Institut für Bioengineering (688)
- INB - Institut für Nano- und Biotechnologien (615)
Language
- German (5099)
- English (4907)
- Russian (14)
- Portuguese (6)
- Multiple languages (5)
- Spanish (3)
- Dutch (2)
- Italian (1)
Document Type
- Article (5644)
- Conference Proceeding (1639)
- Book (1079)
- Part of a Book (559)
- Bachelor Thesis (312)
- Patent (174)
- Report (101)
- Doctoral Thesis (79)
- Other (76)
- Administrative publication (76)
Keywords
- Amtliche Mitteilung (71)
- Bachelor (33)
- Aachen University of Applied Sciences (31)
- Master (31)
- Prüfungsordnung (31)
- Bauingenieurwesen (30)
- Lesbare Fassung (28)
- Biosensor (25)
- Fachhochschule Aachen (23)
- Illustration (22)
Zugriffsart
- campus (2140)
- weltweit (1860)
- bezahl (764)
- fachbereichsweit (FB4) (30)
In this paper the results of a techno-economic analysis of improved and optimized molten salt solar tower plants (MSSTP plants) are presented. The potential improvements that were analyzed include different receiver designs, different designs of the HTF-system and plant control, increased molten salt temperatures (up to 640°C) and multi-tower systems. Detailed technological and economic models of the solar field, solar receiver and high temperature fluid system (HTF-system) were developed and used to find potential improvements compared to a reference plant based on Solar Two technology and up-to-date cost estimations. The annual yield model calculates the annual outputs and the LCOE of all variants. An improved external tubular receiver and improved HTF-system achieves a significant decrease of LCOE compared to the reference. This is caused by lower receiver cost as well as improvements of the HTF-system and plant operation strategy, significantly reducing the plant own consumption. A novel star receiver shows potential for further cost decrease. The cavity receiver concepts result in higher LCOE due to their high investment cost, despite achieving higher efficiencies. Increased molten salt temperatures seem possible with an adapted, closed loop HTF-system and achieve comparable results to the original improved system (with 565°C) under the given boundary conditions. In this analysis all multi tower systems show lower economic viability compared to single tower systems, caused by high additional cost for piping connections and higher cost of the receivers.
REFERENCES
Aktuelle Ehrenämter und Möglichkeiten des Austauschs sind in alten Strukturen festgefahren und erfahren wenig Aufmerksamkeit. Die Potenziale von älteren Generationen werden zu selten geschätzt und ausgeschöpft. Dazu werden Sie in vielen neuen Dingen und Anwendungen nicht als Nutzer:innengruppe beachtet und somit Schritt für Schritt ausgegrenzt. Der Ansatz dieser Arbeit war es, eine gesellschaftlich fördernde digitale Oberfläche für den Generationenaustausch zwischen jung und alt zu schaffen - unabhängig von Vereinsstrukturen oder Organisationen. Vereinen wir das Bewusstsein der Alten mit der Neugier und Innovationskraft der Jungen, um eine Zukunft zu schaffen, in der es sich lohnt, jung zu sein, als auch alt zu werden.
The conference center darmstadtium in Darmstadt is a prominent example of energy efficient buildings. Its heating system consists of different source and consumer circuits connected by a Zortström reservoir. Our goal was to reduce the energy costs of the system as much as possible. Therefore, we analyzed its supply circuits. The first step towards optimization is a complete examination of the system: 1) Compilation of an object list for the system, 2) collection of the characteristic curves of the components, and 3) measurement of the load profiles of the heat and volume-flow demand. Instead of modifying the system manually and testing the solution by simulation, the second step was the creation of a global optimization program. The objective was to minimize the total energy costs for one year. We compare two different topologies and show opportunities for significant savings.
Booster stations can fulfill a varying pressure demand with high energy-efficiency, because individual pumps can be deactivated at smaller loads. Although this is a seemingly simple approach, it is not easy to decide precisely when to activate or deactivate pumps. Contemporary activation controls derive the switching points from the current volume flow through the system. However, it is not measured directly for various reasons. Instead, the controller estimates the flow based on other system properties. This causes further uncertainty for the switching decision. In this paper, we present a method to find a robust, yet energy-efficient activation strategy.
An interdisciplinary view on humane interfaces for digital shadows in the internet of production
(2022)
Digital shadows play a central role for the next generation industrial internet, also known as Internet of Production (IoP). However, prior research has not considered systematically how human actors interact with digital shadows, shaping their potential for success. To address this research gap, we assembled an interdisciplinary team of authors from diverse areas of human-centered research to propose and discuss design and research recommendations for the implementation of industrial user interfaces for digital shadows, as they are currently conceptualized for the IoP. Based on the four use cases of decision support systems, knowledge sharing in global production networks, human-robot collaboration, and monitoring employee workload, we derive recommendations for interface design and enhancing workers’ capabilities. This analysis is extended by introducing requirements from the higher-level perspectives of governance and organization.
Purpose
This study aims to investigate the biomechanics of handcycling during a continuous load trial (CLT) to assess the mechanisms underlying fatigue in upper body exercise.
Methods
Twelve able-bodied triathletes performed a 30-min CLT at a power output corresponding to lactate threshold in a racing recumbent handcycle mounted on a stationary ergometer. During the CLT, ratings of perceived exertion (RPE), tangential crank kinetics, 3D joint kinematics, and muscular activity of ten muscles of the upper extremity and trunk were examined using motion capturing and surface electromyography.
Results
During the CLT, spontaneously chosen cadence and RPE increased, whereas crank torque decreased. Rotational work was higher during the pull phase. Peripheral RPE was higher compared to central RPE. Joint range of motion decreased for elbow-flexion and radial-duction. Integrated EMG (iEMG) increased in the forearm flexors, forearm extensors, and M. deltoideus (Pars spinalis). An earlier onset of activation was found for M. deltoideus (Pars clavicularis), M. pectoralis major, M. rectus abdominis, M. biceps brachii, and the forearm flexors.
Conclusion
Fatigue-related alterations seem to apply analogously in handcycling and cycling. The most distal muscles are responsible for force transmission on the cranks and might thus suffer most from neuromuscular fatigue. The findings indicate that peripheral fatigue (at similar lactate values) is higher in handcycling compared to leg cycling, at least for inexperienced participants. An increase in cadence might delay peripheral fatigue by a reduced vascular occlusion. We assume that the gap between peripheral and central fatigue can be reduced by sport-specific endurance training.
This study aims to quantify the kinematics, kinetics and muscular activity of all-out handcycling exercise and examine their alterations during the course of a 15-s sprint test. Twelve able-bodied competitive triathletes performed a 15-s all-out sprint test in a recumbent racing handcycle that was attached to an ergometer. During the sprint test, tangential crank kinetics, 3D joint kinematics and muscular activity of 10 muscles of the upper extremity and trunk were examined using a power metre, motion capturing and surface electromyography (sEMG), respectively. Parameters were compared between revolution one (R1), revolution two (R2), the average of revolution 3 to 13 (R3) and the average of the remaining revolutions (R4). Shoulder abduction and internal-rotation increased, whereas maximal shoulder retroversion decreased during the sprint. Except for the wrist angles, angular velocity increased for every joint of the upper extremity. Several muscles demonstrated an increase in muscular activation, an earlier onset of muscular activation in crank cycle and an increased range of activation. During the course of a 15-s all-out sprint test in handcycling, the shoulder muscles and the muscles associated to the push phase demonstrate indications for short-duration fatigue. These findings are helpful to prevent injuries and improve performance in all-out handcycling.
Kinematics and kinetics of handcycling propulsion at increasing workloads in able-bodied subjects
(2018)
In Paralympic sports, biomechanical optimisation of movements and equipment seems to be promising for improving performance. In handcycling, information about the biomechanics of this sport is mainly provided by case studies. The aim of the current study was (1) to examine changes in handcycling propulsion kinematics and kinetics due to increasing workloads and (2) identify parameters that are associated with peak aerobic performance. Twelve non-disabled male competitive triathletes without handcycling experience voluntarily participated in the study. They performed an initial familiarisation protocol and incremental step test until exhaustion in a recumbent racing handcycle that was attached to an ergometer. During the incremental test, tangential crank kinetics, 3D joint kinematics, blood lactate and ratings of perceived exertion (local and global) were identified. As a performance criterion, the maximal power output during the step test (Pmax) was calculated and correlated with biomechanical parameters. For higher workloads, an increase in crank torque was observed that was even more pronounced in the pull phase than in the push phase. Furthermore, participants showed an increase in shoulder internal rotation and abduction and a decrease in elbow flexion and retroversion. These changes were negatively correlated with performance. At high workloads, it seems that power output is more limited by the transition from pull to push phase than at low workloads. It is suggested that successful athletes demonstrate small alterations of their kinematic profile due to increasing workloads. Future studies should replicate and expand the test spectrum (sprint and continuous loads) as well as use methods like surface electromyography (sEMG) with elite handcyclists.
Muscular activity in terms of surface electromyography (sEMG) is usually normalised to maximal voluntary isometric contractions (MVICs). This study aims to compare two different MVIC-modes in handcycling and examine the effect of moving average window-size. Twelve able-bodied male competitive triathletes performed ten MVICs against manual resistance and four sport-specific trials against fixed cranks. sEMG of ten muscles [M. trapezius (TD); M. pectoralis major (PM); M. deltoideus, Pars clavicularis (DA); M. deltoideus, Pars spinalis (DP); M. biceps brachii (BB); M. triceps brachii (TB); forearm flexors (FC); forearm extensors (EC); M. latissimus dorsi (LD) and M. rectus abdominis (RA)] was recorded and filtered using moving average window-sizes of 150, 200, 250 and 300 ms. Sport-specific MVICs were higher compared to manual resistance for TB, DA, DP and LD, whereas FC, TD, BB and RA demonstrated lower values. PM and EC demonstrated no significant difference between MVIC-modes. Moving average window-size had no effect on MVIC outcomes. MVIC-mode should be taken into account when normalised sEMG data are illustrated in handcycling. Sport-specific MVICs seem to be suitable for some muscles (TB, DA, DP and LD), but should be augmented by MVICs against manual/mechanical resistance for FC, TD, BB and RA.
Von der Königlichen Höheren Maschinenbauschule Aachen zu den Ingenieurfachbereichen der FH Aachen
(2010)
75 Jahre Vereinsgeschichte
(2010)
Ein Bicharakteristikenverfahren zur Berechnung von Spannungswellen in krummlinig berandeten Scheiben
(1986)
Wohlfühlen in den eigenen vier Wänden : ein Produkt, welches die Wohn- und Lebensqualität steigert.
(2023)
Viele Menschen fühlen sich in ihren eigenen vier Wänden nicht wohl. Sie sind gestresst und können nicht entspannen. Ziel dieser Arbeit ist es, ein Produkt zu erschaffen, welches in seinen Funktionen und seinem Design dafür sorgt, dass die Nutzer:innen sich zu Hause wohler fühlen. Es soll alle Funktionen vereinen, die dafür sorgen, dass der Alltagsstress besser bewältigt werden kann und man in seinem Zuhause entspannen kann und den Moment mehr genießt. Entstanden ist Iwa, ein Produkt, welches zum einen als Luftreiniger arbeitet und die Raumluft filtert und im Zusammenspiel mit Licht und Musik die Raumatmosphäre verbessert und so Stress mindert. Das Design soll genau wie die Funktionen beruhigend, entspannend und erdend wirken. Es ist angelehnt am Zen-Design. So bietet Iwa einen großen Mehrwert. Die Funktionen sorgen im Zusammenspiel mit dem Design für eine verbesserte Wohn- und Lebensqualität.
Magnetic detection structure for Lab-on-Chip applications based on the frequency mixing technique
(2018)
A magnetic frequency mixing technique with a set of miniaturized planar coils was investigated for use with a completely integrated Lab-on-Chip (LoC) pathogen sensing system. The system allows the detection and quantification of superparamagnetic beads. Additionally, in terms of magnetic nanoparticle characterization ability, the system can be used for immunoassays using the beads as markers. Analytical calculations and simulations for both excitation and pick-up coils are presented; the goal was to investigate the miniaturization of simple and cost-effective planar spiral coils. Following these calculations, a Printed Circuit Board (PCB) prototype was designed, manufactured, and tested for limit of detection, linear response, and validation of theoretical concepts. Using the magnetic frequency mixing technique, a limit of detection of 15 µg/mL of 20 nm core-sized nanoparticles was achieved without any shielding.
A concept for a sensitive micro total analysis system for high throughput fluorescence imaging
(2006)
This paper discusses possible methods for on-chip fluorescent imaging for integrated bio-sensors. The integration of optical and electro-optical accessories, according to suggested methods, can improve the performance of fluorescence imaging. It can boost the signal to background ratio by a few orders of magnitudes in comparison to conventional discrete setups. The methods that are present in this paper are oriented towards building reproducible arrays for high-throughput micro total analysis systems (µTAS). The first method relates to side illumination of the fluorescent material placed into microcompartments of the lab-on-chip. Its significance is in high utilization of excitation energy for low concentration of fluorescent material. The utilization of a transparent µLED chip, for the second method, allows the placement of the excitation light sources on the same optical axis with emission detector, such that the excitation and emission rays are directed controversly. The third method presents a spatial filtering of the excitation background.
Size unlimited markerless deletions by a transconjugative plasmid-system in Bacillus licheniformis
(2013)
As researchers continue to seek the expansion of the material base for additive manufacturing, there is a need to focus attention on the Ni–Cu group of alloys which conventionally has wide industrial applications. In this work, the G-NiCu30Nb casting alloy, a variant of the Monel family of alloys with Nb and high Si content is, for the first time, processed via the laser powder bed fusion process (LPBF). Being novel to the LPBF processes, optimum LPBF parameters were determined, and hardness and tensile tests were performed in as-built conditions and after heat treatment at 1000 °C. Microstructures of the as-cast and the as-built condition were compared. Highly dense samples (99.8% density) were achieved after varying hatch distance (80 µm and 140 µm) with scanning speed (550 mm/s–1500 mm/s). There was no significant difference in microhardness between varied hatch distance print sets. Microhardness of the as-built condition (247 HV0.2) exceeded the as-cast microhardness (179 HV0.2.). Tensile specimens built in vertical (V) and horizontal (H) orientations revealed degrees of anisotropy and were superior to conventionally reported figures. Post heat treatment increased ductility from 20% to 31% (V), as well as from 16% to 25% (H), while ultimate tensile strength (UTS) and yield strength (YS) were considerably reduced.
Information and communication technology for integrated mobility concepts such as E-carsharing
(2015)
During the past decade attitude towards sharing things has changed extremely. Not just personal data is shared (e.g. in social networks) but also mobility. Together with the increased ecological awareness of the recent years, new mobility concepts have evolved. E-carsharing has become a symbol for these changes of attitude. The management of a shared car fleet, the energy management of electric mobility and the management of various carsharing users with individual likes and dislikes are just some of the major challenges of e-carsharing. Weaving it into integrated mobility concepts, this raises complexity even further. These challenges can only be overcome by an appropriate amount of well-shaped information available at the right place and time. In order to gather, process and share the required information, fleet cars have to be equipped with modern information and communication technology (ICT) and become so-called fully connected cars. Ensuring the usability of these ICT systems is another challenge that is often neglected, even though it is usability that makes carsharing comfortable, attractive and supports users’ new attitudes. By means of an integrated and consistent concept for human-machine interaction (HMI), the usability of such systems can be raised tremendously.
Die Informationsbroschüre „Elektromobilität in einer vernetzten Welt“ richtet sich an IT-Dienstleister. In dieser Broschüre werden mögliche Potenziale im Bereich der Elektromobilität aufgezeigt. Die Mobilität der Zukunft ist eine interdisziplinäre Angelegenheit und kein reines Automotive-Thema mehr. Beispiele wie Mobilitätsmanagement, eCommerce und Individualisierung sind im Mobilitätsbereich für die IT-Branche relevant.
Inmitten des Stuttgarter Kessels findet sich Deutschlands einziger zoologisch-botanischer Garten wieder – die Wilhelma. Umrahmt von einer denkmalgeschützten Parkanlage des 19. Jahrhunderts mit maurischen Gebäuden lässt sie Bildung mit Freizeit verschmelzen. Das neue Erscheinungsbild positioniert die schwäbische Einrichtung sowohl als Ort des Zusammenkommens als auch der Erholung und Wissensvermittlung. Bereits vor dem Betreten der Wilhelma soll ihre besondere Charakteristik aufgezeigt und entscheidend von ähnlichen Institutionen distanziert werden. Das grundlegende Gestaltungskonzept rückt die Symbiose aus Zoologie, Botanik und Historie in den Vordergrund. Inspiriert von der maurischen Architektur basiert die Gesamtgestaltung auf feinen geometrischen Formen. Diese bieten Orientierung, unterstreichen die Vielfältigkeit der Wilhelma und vereinen sich darüber hinaus im Logo miteinander.
Multi-dimensional fragility analysis of a RC building with components using response surface method
(2017)
Conventional fragility curves describe the vulnerability of the main structure under external hazards. However, in complex structures such as nuclear power plants, the safety or the risk depends also on the components associated with a system. The classical fault tree analysis gives an overall view of the failure and contains several subsystems to the main event, however, the interactions in the subsystems are not well represented. In order to represent the interaction of the components, a method suggested by Cimellaro et al. (2006) using multidimensional performance limit state functions to obtain the system fragility curves is adopted. This approach gives the possibility of deriving the cumulative fragility taking into account the interaction of the response of different components. In this paper, this approach is used to evaluate seismic risk of a representative electrical building infrastructure, including the component, of a nuclear power plant. A simplified model of the structure, with nonlinear material behavior is employed for the analysis in Abaqus©. The input variables considered are the material parameters, boundary conditions and the seismic input. The variability of the seismic input is obtained from selected ground motion time histories of spectrum compatible synthetic ccelerograms. Unlike the usual Monte Carlo methods used for the probabilistic analysis of the structure, a computationally effective response surface method is used. This method reduces the computational effort of the calculations by reducing the required
number of samples.
Human induced pluripotent stem cells (hiPSCs) have shown to be promising in disease studies and drug screenings [1]. Cardiomyocytes derived from hiPSCs have been extensively investigated using patch-clamping and optical methods to compare their electromechanical behaviour relative to fully matured adult cells. Mathematical models can be used for translating findings on hiPSCCMs to adult cells [2] or to better understand the mechanisms of various ion channels when a drug is applied [3,4]. Paci et al. (2013) [3] developed the first model of hiPSC-CMs, which they later refined based on new data [3]. The model is based on iCells® (Fujifilm Cellular Dynamics, Inc. (FCDI), Madison WI, USA) but major differences among several cell lines and even within a single cell line have been found and motivate an approach for creating sample-specific models. We have developed an optimisation algorithm that parameterises the conductances (in S/F=Siemens/Farad) of the latest Paci et al. model (2018) [5] using current-voltage data obtained in individual patch-clamp experiments derived from an automated patch clamp system (Patchliner, Nanion Technologies GmbH, Munich).
Masked hypertension is known to induce microvascular complications. However, it is unclear whether early microvascular changes are already occurring in young, otherwise healthy adults. We therefore investigated whether retinal microvascular calibers and acute responses to a flicker stimulus are related to masked hypertension. We used the baseline data of 889 participants aged 20–30 years who were taking part in the African Prospective study on the Early Detection and Identification of Cardiovascular Disease and Hypertension. Clinic and 24-h ambulatory blood pressure were measured. The central retinal artery equivalent (CRAE) and central retinal vein equivalent were calculated from fundus images, and retinal vessel dilation was determined in response to flicker light-induced provocation. A smaller CRAE was observed in those with masked hypertension vs. those with normotension (157.1 vs. 161.2 measuring units, P < 0.001). In forward multivariable-adjusted regression analysis, only CRAE was negatively related to masked hypertension [adjusted R² = 0.267, β = −0.097 (95% CI = −0.165; −0.029), P = 0.005], but other retinal microvascular parameters were not associated with masked hypertension. In multivariable logistic regression analyses, masked hypertension [OR = 2.333, (95% CI = 1.316; 4.241), P = 0.004] was associated with a narrower CRAE. In young healthy adults, masked hypertension was associated with retinal arteriolar narrowing, thereby reflecting early microvascular alterations known to predict cardiovascular outcomes in later life.
The increasing complexity of Advanced Driver Assistance Systems (ADAS) presents a challenging task to validate safe and reliable performance of these systems under varied conditions. The test and validation of ADAS/AD with real test drives, although important, involves huge costs and time. Simulation tools provide an alternative with the added advantage of reproducibility but often use ideal sensors, which do not reflect real sensor output accurately. This paper presents a new validation methodology using fault injection, as recommended by the ISO 26262 standard, to test software and system robustness. In our work, we investigated and developed a tool capable of inserting faults at different software and system levels to verify its robustness. The scope of this paper is to cover the fault injection test for the Visteon’s DriveCore™ system, a centralized domain controller for Autonomous driving which is sensor agnostic and SoC agnostic. With this new approach, the validation of safety monitoring functionality and its behavior can be tested using real-world data instead of synthetic data from simulation tools resulting in having better confidence in system performance before proceeding with in-vehicle testing.
Das Multimar Wattforum ist das größte Informationszentrum zum Thema Wattenmeer in Deutschland. Auf über 3000 Quadratmetern können große und kleine Besucher:innen eine interaktive Ausstellung über Wale, Watt und Weltnaturerbe bestaunen. Das Wattenmeer ist ein ganz besonderer Lebensraum und bietet vielen Lebewesen Zuflucht. Es wird durch die Gezeiten geprägt, bei Ebbe trocken und der Sonne ausgesetzt, bei Flut nass und salzig. Das neue Erscheinungsbild für das Multimar Wattforum soll die zentralen Werte und Alleinstellungsmerkmale hervorheben und dem Informationszentrum helfen, seiner Aufgabe als bildende, wissenschaftliche und schützende Einrichtung gerecht zu werden. So wurde ein einheitliches und skalierbares Erscheinungsbild und eine flexible Bild- und Wortmarke entwickel