scispace - formally typeset
Search or ask a question
Institution

University of Stuttgart

EducationStuttgart, Germany
About: University of Stuttgart is a education organization based out in Stuttgart, Germany. It is known for research contribution in the topics: Laser & Finite element method. The organization has 27715 authors who have published 56370 publications receiving 1363382 citations. The organization is also known as: Universität Stuttgart.


Papers
More filters
Journal ArticleDOI
C. Stewen1, K. Contag, M. Larionov, A. Giesen, H Hugel 
TL;DR: In this paper, the authors presented an optimal laser design for the operation of a quasi-three-level laser active medium in the high power regime with high optical efficiency, and showed that operation with an output power up to 1 kW with an optical efficiency of 50% and more is possible at room temperature utilizing 16 absorption passes.
Abstract: The thin disc laser is presented as an optimal laser design for the operation of a quasi-three-level laser active medium in the high power regime with high optical efficiency. Numerical calculations of the laser output power show that operation with an output power up to 1 kW with an optical efficiency of 50% and more is possible at room temperature utilizing 16 absorption passes. Scaling of the output power can be realized by scaling the pumped area using one or more discs. The experimental investigations yield a maximum output power of 647 W at 51% optical efficiency for one crystal and of 1070 W with 48% optical efficiency for four crystals at a temperature of the cooling water of 15/spl deg/C.

304 citations

Journal ArticleDOI
TL;DR: It was shown that strain Pseudomonas sp.
Abstract: The taxonomic position of Pseudomonas sp. B13T, isolated as a 3-chlorobenzoate-degrading organism and used for several groundbreaking studies on the enzymology and genetics of the degradative pathway for haloaromatic compounds, was studied in detail. The previously performed physiological studies, the detection of ubiquinone Q-9, the polyamine pattern with putrescine and spermidine as major polyamines, a fatty acid profile with C18 : 1 ω7c, summed feature 3 and C16 : 0 as quantitatively the most important constituents and the 16S rRNA gene sequence demonstrated that Pseudomonas sp. B13T indeed belongs to the genus Pseudomonas. The sequence of the Pseudomonas sp. B13T 16S rRNA gene demonstrated a high degree of similarity with that of Pseudomonas citronellolis DSM 50332T (98.9 %), Pseudomonas nitroreducens DSM 14399T (98.7 %), Pseudomonas jinjuensis DSM 16612T (98.1 %) and Pseudomonas multiresinivorans DSM 17553T (98.7 %). Thus it was shown that strain Pseudomonas sp. B13T can be distinguished from related species by the ability/inability to assimilate N-acetylgalactosamine, d-galactose, putrescine, trans-aconitate and mesaconate and some differences in the fatty acid profile. The positioning of Pseudomonas sp. B13T as a separate taxon was finally verified by DNA hybridization, which demonstrated less than 45 % DNA–DNA similarity between strain Pseudomonas sp. B13T and the reference strains. On the basis of these results, Pseudomonas sp. B13T represents a novel species for which the name Pseudomonas knackmussii sp. nov. is proposed. The type strain is B13T (=DSM 6978T=LMG 23759T).

303 citations

Journal ArticleDOI
TL;DR: In this article, a double-K criterion is proposed to predict the crack propagation during the fracture process in quasi-brittle materials, which consists of two size-independent parameters, i.e., initial cracking toughness and unstable fracture toughness.
Abstract: The results of experimental investigations using laser speckle interferometry on small size three-point bending notched beams and using photoelastic coating and the strain gauges on very large size compact tension specimens of concrete are presented in detail. The investigations showed that there exists a stage of stable crack propagation before unstable fracture occurs. The results are in agreement with other researchers' investigations using moire interferometry, holographic interferometry, dye-impregnation method and microscope. Further detailed study shows that the three different states, i.e., crack initiation, stable crack propagation and unstable fracture can be distinguished in the fracture process in concrete structures. In order to predict the crack propagation during the fracture process in quasi-brittle materials a double-K criterion is proposed. The double-K criterion consists of two size-independent parameters. Both of them are expressed in terms of the stress intensity factors. One of them reflects the initial cracking toughness, denoted with Kini, which can be directly evaluated by the initial cracking load, Pini, and the precast crack length, a0, using a formula of LEFM. The other one refers to the unstable fracture toughness, denoted with Kun, which can be obtained inserting the maximum load, Pmax, and the effective crack length, a, into the same formula of LEFM. The values of the two parameters, KIcini and KIcun, obtained from the small size three-point bending notched beams and the large size compact tension specimens show that KIcini and KIcun are size-independent. Evaluating with the K-resistance curves obtained from the same test data, it is found that the proposed double-K criterion is equivalent to it in basic principle, but, the double-K criterion can be applied more easily than the K-resistance curve. Finally, as a practical example, the application of the double-K criterion to the prediction of the crack propagation in a concrete dam is discussed.

303 citations

Proceedings ArticleDOI
26 Apr 2014
TL;DR: This paper presents the first large-scale analysis of mobile notifications with a focus on users' subjective perceptions, and derives a holistic picture of notifications on mobile phones by collecting close to 200 million notifications from more than 40,000 users.
Abstract: Notifications are a core feature of mobile phones. They inform users about a variety of events. Users may take immediate action or ignore them depending on the importance of a notification as well as their current context. The nature of notifications is manifold, applications use them both sparsely and frequently. In this paper we present the first large-scale analysis of mobile notifications with a focus on users' subjective perceptions. We derive a holistic picture of notifications on mobile phones by collecting close to 200 million notifications from more than 40,000 users. Using a data-driven approach, we break down what users like and dislike about notifications. Our results reveal differences in importance of notifications and how users value notifications from messaging apps as well as notifications that include information about people and events. Based on these results we derive a number of findings about the nature of notifications and guidelines to effectively use them.

303 citations

Journal ArticleDOI
TL;DR: The current framework provides a preliminary overview of factors which may account for PA behaviour across the life course and are most relevant to the European community.
Abstract: A large proportion of European children, adults and older adults do not engage in sufficient physical activity (PA). Understanding individual and contextual factors associated with PA behaviours is essential for the identification and implementation of effective preventative environments, policies, and programmes that can promote an active lifestyle across life course and can potentially improve health. The current paper intends to provide 1) a multi-disciplinary, Pan-European and life course view of key determinants of PA behaviours and 2) a proposal of how these factors may cluster. After gathering a list of 183 potential PA behaviours-associated factors and a consensus meeting to unify/consolidate terminology, a concept mapping software was used to collate European experts’ views of 106 identified factors for youth (<19 years), adults (19–64 years), and older adults (≥65 years). The analysis evaluated common trends in the clustering of factors and the ratings of the distinct factors’ expected modifiability and population-level impact on PA behaviours across the life course. Priority for research was also assessed for each cluster. The concept mapping resulted in six distinct clusters, broadly merged in two themes: 1) the ‘Person’, which included clusters ‘Intra-Personal Context and Wellbeing’ and ‘Family and Social Economic Status’ (42 % of all factors) and 2) the ‘Society’, which included the remaining four clusters ‘Policy and Provision’, ‘Cultural Context and Media’, ‘Social Support and Modelling’, and ‘Supportive Environment’ (58 % of all factors). Overall, 25 factors were rated as the most impactful on PA behaviours across the life course and being the most modifiable. They were mostly situated in the ‘Intra-Personal Context and Wellbeing’ cluster. Furthermore, 16 of them were rated as top priority for research. The current framework provides a preliminary overview of factors which may account for PA behaviour across the life course and are most relevant to the European community. These insights could potentially be a foundation for future Pan-European research on how these factors might interact with each other, and assist policy makers to identify appropriate interventions to maximize PA behaviours and thus the health of European citizens.

303 citations


Authors

Showing all 28043 results

NameH-indexPapersCitations
Yi Chen2174342293080
Robert J. Lefkowitz214860147995
Michael Kramer1671713127224
Andrew G. Clark140823123333
Stephen D. Walter11251357012
Fedor Jelezko10341342616
Ulrich Gösele10260346223
Dirk Helbing10164256810
Ioan Pop101137047540
Niyazi Serdar Sariciftci9959154055
Matthias Komm9983243275
Hans-Joachim Werner9831748508
Richard R. Ernst9635253100
Xiaoming Sun9638247153
Feng Chen95213853881
Network Information
Related Institutions (5)
École Polytechnique Fédérale de Lausanne
98.2K papers, 4.3M citations

95% related

RWTH Aachen University
96.2K papers, 2.5M citations

94% related

ETH Zurich
122.4K papers, 5.1M citations

94% related

University of Erlangen-Nuremberg
85.6K papers, 2.6M citations

93% related

Technische Universität München
123.4K papers, 4M citations

93% related

Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
2023147
2022482
20212,588
20202,646
20192,654
20182,525