No (14168)
Yes (1997)
Number of found documents:
16165
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GA 19-07635S: Outputs and Results
Rehák, Branislav
2023 - English
This manuscript aims to deliver a survey of results obtained during the solution of the project No. GA19-07635S of the Czech Science Foundation. The timespan dedicated to the work on this project was 1.3.2019 - 30.6.2022. The main area dealt with were\nnonlinear multi-agent systems and their synchronization, further, attention was paid to some auxiliary results in the area of nonlinear observers. This Report briefly introduces the Project, provides a summary of the results obtained and also sketches an outline how these results will be applied and extended in future.
Keywords:
multi-agent systems; nonlinear multi-agent systems; synchronization
Fulltext is available at external website.
GA 19-07635S: Outputs and Results
This manuscript aims to deliver a survey of results obtained during the solution of the project No. GA19-07635S of the Czech Science Foundation. The timespan dedicated to the work on this project was ...
Some modifications of the limited-memory variable metric optimization methods
Vlček, Jan; Lukšan, Ladislav
2023 - English
Several modifications of the limited-memory variable metric (or quasi-Newton) line search methods for large scale unconstrained optimization are investigated. First the block version of the symmetric rank-one (SR1) update formula is derived in a similar way as for the block BFGS update in Vlˇcek and Lukˇsan (Numerical Algorithms 2019). The block SR1 formula is then modified to obtain an update which can reduce the required number of arithmetic operations per iteration. Since it usually violates the corresponding secant conditions, this update is combined with the shifting investigated in Vlˇcek and Lukˇsan (J. Comput. Appl. Math. 2006). Moreover, a new efficient way how to realize the limited-memory shifted BFGS method is proposed. For a class of methods based on the generalized shifted economy BFGS update, global convergence is established. A numerical comparison with the standard L-BFGS and BNS methods is given.
Keywords:
unconstrained minimization; variable metric methods; limited-memory methods; variationally derived methods; arithmetic operations reduction; global convergence
Available in a digital repository NRGL
Some modifications of the limited-memory variable metric optimization methods
Several modifications of the limited-memory variable metric (or quasi-Newton) line search methods for large scale unconstrained optimization are investigated. First the block version of the symmetric ...
Analýza malty z 19. století
Bauerová, Pavla; Frankeová, Dita; Slížková, Zuzana; Vondráčková, Michaela
2023 - Czech
Chemické a mineralogické složení pojiva a plniva malty pomocí elektronové mikroskopie (SEM-EDS) a termické analýzy Chemical and mineralogical composition of the binder and the aggregates of the mortar, using SEM-EDS and thermal analysis
Keywords:
SEM-EDS analysis; historic mortar; hydraulic lime; decalcification; carbonatization
Available at various institutes of the ASCR
Analýza malty z 19. století
Chemické a mineralogické složení pojiva a plniva malty pomocí elektronové mikroskopie (SEM-EDS) a termické analýzy...
2TDK Railway, profile P18. Datings. Final Report.
Bosák, Pavel; Zupan Hajna, N.; Hercman, H.; Horáček, I.; Kdýr, Šimon; Kogovšek, B.
2023 - English
Samples for datings were taken in the railway construction (2TDK) near village of Divača, Classical Karst on October 12, 2021: (1) vertebrate bones in cave 2TDK – 002 at the profile P18, cave entrance appeared during the construction operations on cleaned karst surface in a wall of karst depression. Samples of mammal bones and gastropods were collected in situ on cave bottom, and (2) pieces of speleothems occurring in non in situ position on artificially planated surface near the cave opening were collected. U-series: no numerical date was obtained as geochemistry of sample indicate open system, probably due to recrystallization of sample in soil cover. Paleomagnetism: The transition of N- and R-polarized samples cannot be identified more precisely as U-series radiometric dating yielded no numerical results. The transition easily can represent Brunhes/Matuyama boundary (at 773 ka) as well as any of older such transitions (e. g., base of Jaramillo, base of Olduvai). In any case the speleothem grew in a closed cave space with roof, probably as flowstone (inclusion of red soils above the base) and later as baldachin on eroded allogenic fill of the paleocave. Vertebrate paleontology: bone remains of small and larger vertebrates represent subrecent to Holocene species. Sorex alpinus represents the species quite rare in fossil record, but recetly limited to variegated woodland habitats with high surface humidity. A chamois Rupicapra rupicapra represents a resident species present in Slovenia throughout all stages of a glacial cycle, recently restricted to mountain habitats.
Keywords:
Divača Karst; unroofed cave; speleothem; U-Th dating; paleomagnetism; zoopaleontology
Available at various institutes of the ASCR
2TDK Railway, profile P18. Datings. Final Report.
Samples for datings were taken in the railway construction (2TDK) near village of Divača, Classical Karst on October 12, 2021: (1) vertebrate bones in cave 2TDK – 002 at the profile P18, cave entrance ...
Bohl-Marek decomposition applied to a class of biochemical networks with conservation properties
Papáček, Štěpán; Matonoha, Ctirad; Duintjer Tebbens, Jurjen
2023 - English
This study presents an application of one special technique, further called as Bohl-Marek decomposition, related to the mathematical modeling of biochemical networks with mass conservation properties. We continue in direction of papers devoted to inverse problems of parameter estimation for mathematical models describing the drug-induced enzyme production networks [3]. However, being aware of the complexity of general physiologically based pharmacokinetic (PBPK) models, here we focus on the case of enzyme-catalyzed reactions with a substrate transport chain [5]. Although our ultimate goal is to develop a reliable method for fitting the model parameters to given experimental data, here we study certain numerical issues within the framework of optimal experimental design [6]. Before starting an experiment on a real biochemical network, we formulate an optimization problem aiming to maximize the information content of the corresponding experiment. For the above-sketched optimization problem, the computational costs related to the two formulations of the same biochemical network, being (i) the classical formulation x˙(t) = Ax(t) + b(t) and (ii) the 'quasi-linear' Bohl-Marek formulation x˙M(t) = M(x(t)) xM(t), can be determined and compared.
Keywords:
Mathematical modeling; Biochemical network; Pharmacokinetic (PBPK) models
Fulltext is available at external website.
Bohl-Marek decomposition applied to a class of biochemical networks with conservation properties
This study presents an application of one special technique, further called as Bohl-Marek decomposition, related to the mathematical modeling of biochemical networks with mass conservation properties. ...
Vhodné restaurátorské postupy pro zachování stop opracování kamene. Využití blízké fotogrammetrie k ohodnocení vhodnosti restaurátorských postupů
Cihla, Michal; Frommeltová, E.; Hodač, J.; Kovářová, K.; Pavelka, K.; Panáček, M.; Valach, Jaroslav
2023 - Czech
Tento památkový postup je výsledkem výzkumného projektu s názvem „Topografie povrchu kamene a její aplikace v oblasti restaurování kamenných prvků“ č. DG20P02OVV021, podpořeném Ministerstvem kultury ČR. Cílem památkového postupu bylo ověření vhodnosti a použitelnosti přesných měřičských metod za účelem zhodnocení míry restaurátorského zásahu v oblasti stop po opracování povrchu kamene. Nástrojem pro hodnocení změn topografie kamenných povrchů nesoucích stopy po opracování byla zvolena metoda blízké fotogrammetrie. This preservation procedure is the result of the research project entitled „Building stone surface topography and its application in the field of stone features restoration“ No.DG20P02OVV021, supported by the Ministry of Culture of the Czech Republic. The aim of the preservation procedure was to verify the suitability and applicability of precise measuring methods in order to assess the degree of restoration intervention in the area of traces of stone surface working. The method of close-range photogrammetry was chosen as a tool to evaluate the changes in the topography of stone surfaces bearing traces of working.
Keywords:
stone topography; photogrammetry; stonemason’s tools traces; restoration; conservation; stone; monuments; building stone
Fulltext is available at external website.
Vhodné restaurátorské postupy pro zachování stop opracování kamene. Využití blízké fotogrammetrie k ohodnocení vhodnosti restaurátorských postupů
Tento památkový postup je výsledkem výzkumného projektu s názvem „Topografie povrchu kamene a její aplikace v oblasti restaurování kamenných prvků“ č. DG20P02OVV021, podpořeném Ministerstvem kultury ...
Chemická a mikrostrukturní analýza vzorku asfaltobetonu v bývalém pivovaru v Plasích
Frankeová, Dita; Slížková, Zuzana; Náhunková, Pavla
2023 - Czech
TG analysis revealed a proportion of organic matter (asphalt) in the total mass of the material in the amount of 14% by weight and the content of calcium carbonate in the material in the amount of 53% wt. Calcium carbonate is probably in the form of limestone powder as a fine filler. The coarse fraction of the aggregate is represented by stone grains of size 2-10 mm (33% by weight).
Keywords:
thermal analysis; asphalt floors; asphalt concrete; tar; asphalt composite
Available at various institutes of the ASCR
Chemická a mikrostrukturní analýza vzorku asfaltobetonu v bývalém pivovaru v Plasích
TG analysis revealed a proportion of organic matter (asphalt) in the total mass of the material in the amount of 14% by weight and the content of calcium carbonate in the material in the amount of 53% ...
Vibration mode shape extraction of bladed disk
Mekhalfia, Mohammed Lamine; Procházka, Pavel; Tchawou Tchuisseu, Eder Batista; Maturkanič, Dušan; Hodboď, Robert
2022 - English
This research paper deals with the experimental protocol followed to visualize the vibration mode shape of an aero-engine bladed disk. This study is based on a comparison between the numerical results obtained through Finite element methods (FEM) using ANSYS software and experimentally using the laser Doppler vibrometer. Therefore the bladed disk was transformed into a 3D virtual environment and structural analysis was performed. The results demonstrate a match between the numerical and the experimental one, this match offers the possibility for using the model for future studies.
Keywords:
blade disk; mode shapes; laser doppler vibrometer
Available at various institutes of the ASCR
Vibration mode shape extraction of bladed disk
This research paper deals with the experimental protocol followed to visualize the vibration mode shape of an aero-engine bladed disk. This study is based on a comparison between the numerical results ...
Plasma-synthesised zinc oxide nanoparticle behavior in liquids
Rutherford, D.; Jíra, J.; Kolářová, Kateřina; Matolínová, I.; Remeš, Zdeněk; Kuliček, J.; Padmanaban, D.; Maguire, P.; Mariotti, D.; Rezek, B.
2022 - English
ZnO nanoparticles have been synthesized using non-thermal atmospheric pressure plasma (ZnO-NTP). We investigated the behavior of these ligand-free as a colloid suspension using different solvents, from deionized water to physiological saline and microbial culture broth. We found that the zeta potential of ZnONTP became more negative after exposure to microbial culture broth relative to water, which suggests increased colloid stability. Photoluminescence spectra of ZnO-NTP were similar regardless of liquid type, yet optical and fluorescent images of samples showed different agglomeration behaviour depending on liquid type. Scanning electron microscopy images revealed large agglomerates of ZnO-NTP interacting with the surface of bacteria cells, ranging in size from 200 nm up to 2 µm. We also studied effect of sub-lethal concentrations of ZnO-NTP on bacteria under illumination. There was no significant difference in viable bacteria concentration after 24h exposure to 10 µg/mL ZnO-NTP.
Keywords:
zinc oxide; nanotechnology; colloid suspension; bacteria
Available at various institutes of the ASCR
Plasma-synthesised zinc oxide nanoparticle behavior in liquids
ZnO nanoparticles have been synthesized using non-thermal atmospheric pressure plasma (ZnO-NTP). We investigated the behavior of these ligand-free as a colloid suspension using different solvents, ...
Innovative device for the simulation of environmental conditions and testing of building materials
Cacciotti, Riccardo; Wolf, Benjamin; Macháček, Michael; Frankl, Jiří
2022 - English
Excessive humidity influences the performance of building envelopes and the safety of their occupants. Moisture related problems can indeed impose significant health risks for buildings’ users and even lead, under extreme scenarios, to structural failures. This paper investigates an innovative experimental setup for evaluating the influence of changing environmental conditions on the performance of building materials. It stems out from a broader ongoing research aimed at studying the trends of mould growth on wooden building components. The presented results include the design, construction and numerical validation of a small-scale climatic wind tunnel (2m x 1.8m ca.) to be used for the simulation of natural ventilation and daily humidity and temperature fluctuations. Key findings include the final design of a low cost, modular construction which allows gathering reliable data on the response of building materials exposed to changing boundary conditions, intended for improving current mould growth models. Future work is also suggested.
Keywords:
building envelope; moisture; building material; wind tunnel; performance
Available in digital repository of the ASCR
Innovative device for the simulation of environmental conditions and testing of building materials
Excessive humidity influences the performance of building envelopes and the safety of their occupants. Moisture related problems can indeed impose significant health risks for buildings’ users and ...
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