No (11867)
Yes (2889)
Number of found documents:
14756
Published from
to
COMPUTER SIMULATION STUDY OF THE STABILITY OF UNDERACTUATED BIPEDAL ROBOT MODELS (motivated by Griffin and Grizzle, 2017)
Polach, P.; Anderle, Milan; Zezula, Pavel; Papáček, Štěpán
2023 - English
A key feature for bipedal walkers (robots and humans as well) is their stability or disturbance rejection defined as the ability to deal with unexpected disturbances. The paper by Griffin and Grizzle (2017) have significantly contributed to the shift from flat ground to slopes and steps when evaluating the walking efficiency of their robots. Similarly, in this contribution, based on the appropriate model of robot dynamics and control law, we examine the stability of walking-without-falling for different ground perturbations for a threelink compass gait walker. I.e., we perform the sensitivity analysis of the walking stability of underactuated bipedal walker with respect to certain disturbation using the alaska/MultibodyDynamics simulation tool.
Keywords:
Mechatronics; Bipedal robot; Multibody dynamics; Acrobot; Control applications
Fulltext is available at external website.
COMPUTER SIMULATION STUDY OF THE STABILITY OF UNDERACTUATED BIPEDAL ROBOT MODELS (motivated by Griffin and Grizzle, 2017)
A key feature for bipedal walkers (robots and humans as well) is their stability or disturbance rejection defined as the ability to deal with unexpected disturbances. The paper by Griffin and Grizzle ...
Annular Impinging Jets and an Active Control of Hysteretic Effects
Devani, Yogendrasasidhar; Antošová, Zuzana; Trávníček, Zdeněk
2023 - English
An annular impinging air jet with and without flow control was studied experimentally using measurements of the wall pressure and flow velocity by the Pitot probe. To investigate flow control swirling effects, eight synthetic jets were generated from the nozzle center body. The experiments cover Reynolds numbers 4000–10,000 (evaluated from the outer exit diameter of the annular nozzle). For Re<9000, the bistability and hysteresis were identified and two different flow field patterns (A, B) were found under the same boundary conditions. For higher Re>9000, the hysteresis were not found.
Keywords:
annular jet; impinging jet; hysteresis
Available at various institutes of the ASCR
Annular Impinging Jets and an Active Control of Hysteretic Effects
An annular impinging air jet with and without flow control was studied experimentally using measurements of the wall pressure and flow velocity by the Pitot probe. To investigate flow control swirling ...
Book of Abstracts. 18th Youth Symposium on Experimental Solid Mechanics
Kytýř, Daniel; Doktor, Tomáš; Zlámal, Petr
2023 - English
The YSESM symposium provides a forum for young researchers and engineers, PhD students and students dealing with subjects of experimental mechanics. The Symposium concentrates on current work in all areas of experimental research and its application in solid and fluid mechanics. The topic will particularly concern to: Conventional and Advanced Experimental Methods in Solid and Fluid Mechanics; Non-Destructive Testing and Inspection, Measurements in Material Science, Computer Assisted Testing and Simulation, Engineering Design Simulation, Hybrid Methods, Experimental Techniques – Numerical Simulation, Optical Methods and Image Processing, Measurements in Biomechanics, Sensor Techniques for Micro- and Nano-Applications, Measurement Methods for Forensic Engineering.
Keywords:
experimental mechanics; fluid mechanics; mechanics of solids
Fulltext is available at external website.
Book of Abstracts. 18th Youth Symposium on Experimental Solid Mechanics
The YSESM symposium provides a forum for young researchers and engineers, PhD students and students dealing with subjects of experimental mechanics. The Symposium concentrates on current work in all ...
Souvislost mezi principem nejmenší akce a termodynamickou podmínkou stability
Maršík, František; Trávníček, Zdeněk; Antošová, Zuzana
2023 - English
The extended principle is formulated for a material point (M.P.) X, which has nonzero mass, temperature, and trajectory x(X,t). The Lagrangian of this variation principle is equal to the kinetic energy from which, the internal energy of the material point (which depends on the entropy) and the additional energy caused by the frictional force are subtracted. The relation between the inertial force and the entropy gradient is found and the gravitational force is completely replaced by the entropy gradient. Thanks to the mentioned properties of the total enthalpy, the Thermodynamic criterion of stability of the state of M.P., is formulated.
Keywords:
principle of the least action; thermodynamic stability condition; annular swirl flow
Fulltext is available at external website.
Souvislost mezi principem nejmenší akce a termodynamickou podmínkou stability
The extended principle is formulated for a material point (M.P.) X, which has nonzero mass, temperature, and trajectory x(X,t). The Lagrangian of this variation principle is equal to the kinetic ...
Texture Spectral Similarity Criteria Comparison
Havlíček, Michal; Haindl, Michal
2023 - English
Criteria capable of texture spectral similarity evaluation are presented and compared. From the fifteen evaluated criteria, only four criteria guarantee zero or minimal spectral ranking errors. Such criteria can support texture modeling algorithms by comparing the modeled texture with corresponding synthetic simulations. Another possible application is the development of texture retrieval, classification, or texture acquisition system. These criteria thoroughly test monotonicity and mutual correlation on specifically designed extensive monotonously degrading experiments.
Keywords:
Texture Comparison; Texture Modeling; Texture Retrieval; Texture Classification; Texture Acquisition
Fulltext is available at external website.
Texture Spectral Similarity Criteria Comparison
Criteria capable of texture spectral similarity evaluation are presented and compared. From the fifteen evaluated criteria, only four criteria guarantee zero or minimal spectral ranking errors. Such ...
Book of abstracts of the 1st outdoor seminar of the Department of Optical Materials: Advances in the new materials engineering and study
Buryi, Maksym; Král, Robert
2023 - English
The seminar is dedicated to the main activities of the department of Optical Materials, FZU - Institute of Physics of the Czech Academy of Sciences in the course of national and international collaborations. In particular, the advanced methods of the (nano)materials synthesis, fabrication, and characterization are presented and discussed in detail. The aim of the seminar is to establish more of the effective paths of communication and data exchange by creating and maintaining links among the teams of national and international experts in various fields of physical and chemical knowledge, both experimental and theoretical.
Keywords:
nanomaterials; synthesis; data exchange
Fulltext is available at external website.
Book of abstracts of the 1st outdoor seminar of the Department of Optical Materials: Advances in the new materials engineering and study
The seminar is dedicated to the main activities of the department of Optical Materials, FZU - Institute of Physics of the Czech Academy of Sciences in the course of national and international ...
Stereolithography for manufacturing of advanced porous solids
Drechslerová, V.; Neuhäuserová, M.; Falta, J.; Šleichrt, J.; Kytýř, Daniel
2023 - English
The aim of this paper is focused on benefits of stereolithography (SLA) technology for the fabrication of the lightweight lattice structures with potential for load-bearing function and high absorption of impact energy. SLA is an additive manufacturing technology employing the principle of liquid resins curing moderated by radiation of a wavelength from ultra-violet band where resulting material parameters are tunable by setting of the curing process. The batches of samples manufactured using three different resins were subjected to quasi-static uni-axial tensile and compression tests. Acquired data were processed to derive deformation behaviour expressed as stress-strain diagrams and fundamental material properties. Based on the knowledge obtained from the mechanical tests, the setup of the fabrication parameters, the most suitable resin for manufacturing of the lattice structures and the overall suitability of SLA technology for the fabrication of advanced porous materials, were determined.
Keywords:
stereolithography; advanced porous materials; quasi-static testing; resin; mechanical characteristics
Available at various institutes of the ASCR
Stereolithography for manufacturing of advanced porous solids
The aim of this paper is focused on benefits of stereolithography (SLA) technology for the fabrication of the lightweight lattice structures with potential for load-bearing function and high ...
Caves in Bohemia et Moravia Subterranea by Mauritius Vogt (1669–1730)
Rychnová, L.; Vokurka, Michal
2023 - English
The Manuscript Bohemia et Moravia Subterranea (1729) by Mauritius Vogt reflects the subterranean landscapes and underground spaces based on Athanasius Kircher’s theories. The paper analyses the application of Kirchers’s terminology to the natural phenomena from Bohemia and Moravia. Further, we focused on how Vogt worked with his sources – how far he relied on literature, correspondence, or personal experience.
Keywords:
Mauritius Vogt; caves; subterranean; underground; early modern period
Available at various institutes of the ASCR
Caves in Bohemia et Moravia Subterranea by Mauritius Vogt (1669–1730)
The Manuscript Bohemia et Moravia Subterranea (1729) by Mauritius Vogt reflects the subterranean landscapes and underground spaces based on Athanasius Kircher’s theories. The paper analyses the ...
CECE 2023. 18th International Interdisciplinary Meeting on Bioanalysis
Foret, František; Lavická, Jana; Přikryl, Jan
2023 - English
This year the Proceedings included abstracts of 27 oral and 33 poster presentations. The attached conference proceedings, edited by highly cited scientists, documents the quality of the meeting. Similarly to the previous years the lectures were given by outstanding, highly cited, scientists. The list of speakers as well as more detailed information about the conference can be found on its permanent web at www.ce-ce.org.
Keywords:
bioanalysis; separation; biotechnology
Fulltext is available at external website.
CECE 2023. 18th International Interdisciplinary Meeting on Bioanalysis
This year the Proceedings included abstracts of 27 oral and 33 poster presentations. The attached conference proceedings, edited by highly cited scientists, documents the quality of the meeting. ...
The long-term impact of energy poverty and its mitigation on educational attainment: evidence from China
Martirosyan, Yervand
2023 - English
Existing studies demonstrate the short-run connection between environmental conditions and academic performance. However, the long-term effects of exposure to adverse living conditions on academic achievement remain underexplored. This study investigates the long-term impact of energy poverty, and policy interventions aimed at alleviating it, on the academic performance of Chinese schoolchildren starting from infancy. It specifically utilizes the Huai River Policy, which provides free winter heating exclusively to northern regions in China but not to adjacent southern regions. My findings suggest a significant positive influence of winter heating on schoolchildren’s academic performance, with a more pronounced effect for children born during winter months. The insights gained from this research could inform policy debates to enhance educational outcomes and human well-being.\n
Keywords:
energy poverty; academic performance; climate
Fulltext is available at external website.
The long-term impact of energy poverty and its mitigation on educational attainment: evidence from China
Existing studies demonstrate the short-run connection between environmental conditions and academic performance. However, the long-term effects of exposure to adverse living conditions on academic ...
NRGL provides central access to information on grey literature produced in the Czech Republic in the fields of science, research and education. You can find more information about grey literature and NRGL at service web
Send your suggestions and comments to nusl@techlib.cz
Provider
Other bases