No (14388)
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Investigation of basic mechanical and fracture-mechanical properties of specimens cut from high pressure gas pipeline – locality L177/2 after a twentyone months exposition to moist and dry hydrogen at the pressure 3 MPa
Gajdoš, Lubomír; Šperl, Martin; Šorm, Filip; Bejdl, Jan
2023 - Czech
Investigation of the effect of moist and dry hydrogen pressurized to 3 MPa on mechanical and fracture properties of gas pipeline steel ČSN 13126, tensile specimens, Charpy specimens and CT specimens were kept loaded during the exposition in moist hydrogen, after a 21th months exposition it was found that ductility of tensile specimens and fracture parameters Jin and J0,2 of CT specimens decreased whilst the parameter Jm was slightly increased. Vyšetření vlivu vlhkého a suchého vodíku stlačeného na tlak 3 MPa na mechanické a lomové vlastnosti plynovodní oceli ČSN 13126, tahové vzorky, Charpy vzorky i CT vzorky byly během expozice ve vlhkém vodíku trvale zatíženy, po 21 měsících expozice byl zjištěn pokles tažnosti tahových vzorků, pokles lomových parametrů Jin a J0,2 a mírné zvýšení parametru Jm.
Keywords:
stress-strain diagram; Ramberg-Osgood dependence; impact strength; fracture toughness
Available at various institutes of the ASCR
Investigation of basic mechanical and fracture-mechanical properties of specimens cut from high pressure gas pipeline – locality L177/2 after a twentyone months exposition to moist and dry hydrogen at the pressure 3 MPa
Investigation of the effect of moist and dry hydrogen pressurized to 3 MPa on mechanical and fracture properties of gas pipeline steel ČSN 13126, tensile specimens, Charpy specimens and CT specimens ...
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 ...
Chemical and microstructural analysis of sandstone samples from the cemetery portal at the Gothard in Hořice
Slížková, Zuzana; Frankeová, Dita; Bauerová, Pavla; Náhunková, Pavla; Mácová, Petra; Ševčík, Radek; Vondráčková, Michaela
2023 - Czech
Determination of the chemical and mineralogical composition of the surface layer of sandstone and the speed of water transport through the surface of the stone (comparison of the properties of the light ocher surface and the black surface of sandstone. Stanovení chemického a mineralogického složení povrchové vrstvy pískovce a rychlosti transportu vody povrchem kamene (srovnání vlastností světlého povrchu a černého povrchu pískovce).
Keywords:
sandstone; black film; water absorption; chemical composition; mineralogical composition; stone surface
Available at various institutes of the ASCR
Chemical and microstructural analysis of sandstone samples from the cemetery portal at the Gothard in Hořice
Determination of the chemical and mineralogical composition of the surface layer of sandstone and the speed of water transport through the surface of the stone (comparison of the properties of the ...
Instrumental neutron activation analysis of psychoactive substances, mainly heroin, cocaine, metamphetamine and their adulterants
Kameník, Jan; Kučera, Jan
2023 - Czech
Instrumental neutron activation analysis (INAA) is a robust analytical method theoretically well descibed and understood. INAA works with solid samples, dissolution is not required. The methodology introduces INAA background and lists procedures used for quality control. Protocols for INAA of heroin, cocaine and methamphetamine are described in details. Applications of INAA for psychoactive substances includes estimation of purity and adulterants used and drogs profiling. The metodology is based on measurement of laboratory and real samples. Instrumentální neutronová aktivační analýza je založena na robustním teoretickém základu a umožňuje analýzu vzorků v pevném stavu bez nutnosti jejich převedení do roztoku. Text metodiky zahrnuje představení základů INAA a příklady postupů používaných pro kontrolu přesnosti výsledků. Uveden je popis postupu analýzy heroinu, kokainu a metamfetaminu. Aplikace pro využití INAA zahrnují odhad čistoty a použitých ředících látek a profilování vzorků drog. Metodika je založena na analýze laboratorních a reálných vzorků.
Keywords:
NAA; psychotropic substances; methodology
Available at various institutes of the ASCR
Instrumental neutron activation analysis of psychoactive substances, mainly heroin, cocaine, metamphetamine and their adulterants
Instrumental neutron activation analysis (INAA) is a robust analytical method theoretically well descibed and understood. INAA works with solid samples, dissolution is not required. The methodology ...
Methodology for the classification of corrosion aggressiveness of internal environments contaminated with volatile organic acids
Kouřil, M.; Boháčková, T.; Švadlena, J.; Prošek, T.; Strachotová, K. Ch.; Kreislová, K.; Fialová, P.; Majtás, Dušan
2023 - Czech
The aim of the methodology is to specify the procedures for determining the corrosion aggressiveness of internal atmospheres for the area of historic preservation, especially in objects with an increased risk of volatile occurrence\norganic substances, which can endanger metal and other objects with their corrosive aggressiveness cultural and historical value. Target locations are, for example, archives, libraries, exhibition spaces and depositories of museums and churches and target objects of lead seals, organ pipes containing lead, stained glass windows, tin-lead dishes, technical monuments with lead solders, printing letters, etc. Cílem metodiky je konkretizovat postupy určení korozní agresivity vnitřních atmosfér pro oblast památkové péče, zejména v objektech se zvýšeným rizikem výskytu těkavých organických látek, které mohou svou korozní agresivitou ohrožovat kovové i další objekty s kulturní a historickou hodnotou. Cílovými lokalitami tedy jsou například archivy, knihovny, výstavní prostory a depozitáře muzeí a kostely a cílovými předměty olověné pečetě, varhanní píšťaly obsahující olovo, vitráže, cínoolověné nádobí, technické památky s olověnými pájkami, liteřina, apod.
Keywords:
corrosion; lead; cultural heritage
Available at various institutes of the ASCR
Methodology for the classification of corrosion aggressiveness of internal environments contaminated with volatile organic acids
The aim of the methodology is to specify the procedures for determining the corrosion aggressiveness of internal atmospheres for the area of historic preservation, especially in objects with an ...
Geological and geotechnical characterisation of the mining environment - URF Bukov II - Interim report II
Bukovská, Z.; Rukavičková, L.; Chabr, T.; Morávek, R.; Levý, O.; Sosna, K.; Souček, Kamil; Vavro, Martin; Zelinková, T.; Dobeš, P.; Švagera, O.; Kryl, J.; Soejono, I.; Řihošek, J.; Holeček, J.; Hanák, J.; Čermák, F.; Kašpar, R.; Mareček, L.; Nedvěd, J.; Vavro, Leona; Waclawik, Petr; Staš, Lubomír; Myška, O.
2023 - Czech
This report describes the work carried out in the second year of the public contract Geological and geotechnical characterisation of the rock environment – PVP Bukov II. The\ncharacterisation and descriptive works are directly related to the excavation of the premises for the future underground laboratory. These include in particular: geological and geotechnical documentation of the faces and walls of the workings, petrographic, mineralogical and structural geological documentation, hydrogeological characterisation of the environment, as well as determination of the physical and mechanical properties of the rock mass in situ and in the laboratory, geophysical characterisation and monitoring of the seismic effects of blasting and hydrogeological monitoring. An important part of this report is preparation of the classification system used to describe the rock mass. The report also includes a brief overview of the work planned for the third year of the project. Tato zpráva popisuje práce zhotovené v druhém roce řešení veřejné zakázky Geologická a geotechnická charakterizace horninového prostředí – PVP Bukov II. Charakterizační a popisné práce přímo navazují na ražbu prostor pro budoucí podzemní laboratoř a zahrnují zejména: geologické a geotechnické dokumentace čeleb a stěn díla, petrografickou, mineralogickou a strukturně geologickou dokumentaci, hydrogeologickou charakterizaci prostředí, dále stanovení fyzikálně-mechanických vlastností horninového masivu in situ a v laboratoři, geofyzikální charakterizaci a monitoring seismických účinků trhacích prací a hydrogeologický monitoring. Důležitou součástí je příprava klasifikačního systému pro popis horninového masivu. Zpráva je doplněna stručným přehledem prací plánovaných pro třetí rok řešení projektu.
Keywords:
geological documentation; 3D model; petrography; Bukov URF; petrophysical data
Available on request at various institutes of the ASCR
Geological and geotechnical characterisation of the mining environment - URF Bukov II - Interim report II
This report describes the work carried out in the second year of the public contract Geological and geotechnical characterisation of the rock environment – PVP Bukov II. The\ncharacterisation and ...
Evaluation of the areal extremeness of extreme weather events in Czechia in the period of 1961–2020
Kašpar, Marek; Müller, Miloslav
2023 - Czech
Due to the multiplication of impacts of weather extremes when occurring in larger area, we proposed an areal approach of their evaluation. We evaluated six types of extreme weather events, namely, heat waves, cold waves, air temperature drops, windstorms, heavy precipitation, and heavy snowfalls. We employed the original method using the Weather Extremity Index derived from return periods of values of relevant meteorological variables in the affected area. Each event is characterized not only by the areal extremeness quantified with the index but also by the spatial extent and duration. In the studied period, heat and cold\nwaves generally reach higher index values in relation with larger affected area. The increase in the frequency and extremity of heat waves is in contrast with the decrease in the frequency of cold waves and significant heavy snowfalls. The frequency of windstorms is slightly decreasing with the most significant ones concentrated in the cold half-year. Air temperature drops are the most frequent in the warm half-year, nevertheless three of four top events occurred in January. The frequency of heavy precipitation tends to fluctuate. The obtained meteorological database of extreme events may help to estimate the parameters of future ones using climate models. S ohledem na násobné dopady povětrnostních extrémů při zasažení většího území jsme navrhli plošný způsob jejich hodnocení. Hodnotili jsme šest typů extrémních povětrnostních událostí, které zahrnují vlny veder, studené vlny, prudká ochlazení, větrné bouře, silné srážky a silná sněžení. Využili jsme původní metodiku pracující s tzv. indexem extremity počasí odvozeným z dob opakování hodnot příslušných meteorologických veličin v zasažené oblasti. Každá událost je charakterizována nejen plošnou extremitou kvantifikovanou indexem, ale také prostorovým rozsahem a délkou trvání. Vlny veder a studené vlny ve sledovaném období dosahují ve spojitosti s větším prostorovým rozsahem obecně vyšších hodnot indexu. Růst četnosti a extremity vln veder kontrastuje s poklesem četnosti studených vln a významných silných sněžení. Četnost větrných bouří mírně klesá, přičemž nejvýznamnější z nich se koncentrují v chladném půlroce. Prudká ochlazení jsou nejčastější v teplém půlroce, nicméně tři ze čtyř nejextrémnějších událostí se vyskytly v lednu. Četnost silných srážek má tendenci kolísat. Získaná meteorologická databáze extrémních událostí může pomoci při odhadech parametrů budoucích událostí s využitím modelů klimatu.
Keywords:
weather extreme; Weather Extremity Index; return period; meteorological database
Available at various institutes of the ASCR
Evaluation of the areal extremeness of extreme weather events in Czechia in the period of 1961–2020
Due to the multiplication of impacts of weather extremes when occurring in larger area, we proposed an areal approach of their evaluation. We evaluated six types of extreme weather events, namely, ...
Change in precipitation distribution as temperature rises expressed in diagnostic and prognostic data
Sokol, Zbyněk; Řezáčová, Daniela
2023 - Czech
We summarize the main results that show how the distribution of precipitation changes with increasing temperature. Hourly rainfall totals from 97 rain gauge stations in the Czech Republic for the years 1997 to 2019 are used for the evaluation. Ground temperature, ground dew point temperature and temperature at the lifting condensation level are used to express the temperature change. The results show how an increase in temperature and a corresponding increase in saturation humidity (CC scaling) affects the distribution of precipitation in the study area. In general, the increase in precipitation as a function of observed temperature is clearly evident for the upper quantile values, but only for certain temperature intervals. It confirms the findings of other studies. In this paper, data from reanalyses performed by the ALADIN-CLIMAT/CZ model are treated similarly to the measured data.\n Shrnujeme hlavní výsledky, které ukazují, jak se mění rozdělení srážek s rostoucí teplotou. Hodnocení využívá hodinové úhrny z 97 srážkových stanic z území České republiky za roky 1997 až 2019. Hodnoty přízemní teploty, přízemního rosného bodu a výstupné kondenzační hladiny jsou užity pro vyjádření teplotní změny. Výsledky ukazují, jak se teplotní růst napěti nasycení (CC scaling) projevuje v rozložení hodnot srážek na studovaném území. Obecně se nárůst srážek v závislosti na sledovaných teplotách zřetelně projevuje u horních kvantilů avšak pouze pro určité intervaly teplot, což potvrzuje závěry i jiných prací. V práci jsou obdobně jako naměřená data zpracována data z reanalýz provedených modelem ALADINCLIMAT/CZ.\n
Keywords:
Clausius Clapeiron equation; precipitation; dependence of precipitation intensity on temperature
Available at various institutes of the ASCR
Change in precipitation distribution as temperature rises expressed in diagnostic and prognostic data
We summarize the main results that show how the distribution of precipitation changes with increasing temperature. Hourly rainfall totals from 97 rain gauge stations in the Czech Republic for the ...
Identification of quasiperiodic processes in the vicinity of the resonance
Fischer, Cyril; Náprstek, Jiří
2023 - English
In nonlinear dynamical systems, strong quasiperiodic beating effects appear due to combination of self-excited and forced vibration. The presence of symmetric or asymmetric beatings indicates an exchange of energy between individual degrees of freedom of the model or by multiple close dominant frequencies. This effect is illustrated by the case of the van der Pol equation in the vicinity of resonance. The approximate analysis of these nonlinear effects uses the harmonic balance method and the multiple scale method.
Keywords:
dynamical systems; quasiperiodic response; van der Pol equation
Available at various institutes of the ASCR
Identification of quasiperiodic processes in the vicinity of the resonance
In nonlinear dynamical systems, strong quasiperiodic beating effects appear due to combination of self-excited and forced vibration. The presence of symmetric or asymmetric beatings indicates an ...
Laboratory X-ray imaging in material sciences
Koudelka_ml., Petr; Kytýř, Daniel; Jiroušek, O.
2023 - English
In recent decades, X-ray imaging and computed (micro)tomography (XCT) in particular have become common tools for volumetric inspection, visualization, and analysis of internal structure in materials from various fields [1]. In this lecture, we will explore various applications of laboratory X-ray imaging chains utilizing the combination of tomographical imaging with mechanical, thermal, or chemical loading of the irradiated sample in a so-called time-resolved imaging allowing for unprecedented insight into different phenomena driving fundamental processes encountered in various fields of material science. We will show that failure processes in engineering or geological materials [2] can be thoroughly studied by synergy of information from radiographical imaging and other methods including acoustic emission detection and optical measurements via high-speed visible-spectrum and thermal-imaging cameras, where the radiography provides important spatial information regarding deformation processes evolving within the tested samples that could not be obtained otherwise. The state-of-the-art the laboratory based imaging chains for investigation of dynamic response of materials under loading will be also discussed including high speed X-ray radiography utilizing a powerful X-ray source during high velocity impact as an approach suitable for inspection of an impacted sample. As an alternative to both conventional high-power sources and accelerator facilities, capabilities of a flash X-ray system developed primarily for in-situ ballistics research providing very short bursts of an extremely powerful intermittent X-ray radiation with a typical duration of dozens of nanoseconds will be shown.
Keywords:
X-ray imaging; material characterization; mechanical properties
Available at various institutes of the ASCR
Laboratory X-ray imaging in material sciences
In recent decades, X-ray imaging and computed (micro)tomography (XCT) in particular have become common tools for volumetric inspection, visualization, and analysis of internal structure in materials ...
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