Advantageous Description of Short Fatigue Crack Growth Rates in Austenitic Stainless Steels with Distinct Properties

In this work two approaches to the description of short fatigue crack growth rate under large-scale yielding condition were comprehensively tested: (i) plastic component of the J-integral and (ii) Polak model of crack propagation. The ability to predict residual fatigue life of bodies with short initial cracks was studied for stainless steels Sanicro 25 and 304L. Despite their coarse microstructure and very different cyclic stress-strain response, the employed continuum mechanics models were found to give satisfactory results. Finite element modeling was used to determine the J-integrals and to simulate the evolution of crack front shapes, which corresponded to the real cracks observed on the fracture surfaces of the specimens. Residual fatigue lives estimated by these models were in good agreement with the number of cycles to failure of individual test specimens strained at various total strain amplitudes. Moreover, the crack growth rates of both investigated materials fell onto the same curve that was previously obtained for other steels with different properties. Such a "master curve" was achieved using the plastic part of J-integral and it has the potential of being an advantageous tool to model the fatigue crack propagation under large-scale yielding regime without a need of any additional experimental data

How did the distance to the centre in 2020 affect the prices of Prague apartments?

The bachelor thesis deals with the question of how the prices of Prague apartments were affected by the distance to the center in 2020. The main objective of the thesis is to confirm the hypothesis: With the increasing distance to the center of Prague, the price of Prague apartments decreases. Another aim of the thesis is to find out whether alternative factors such as the proximity of the presence of urban greenery and public transport stops had an impact on the price of Prague apartments in 2020. The last goal is to verify whether the city of Prague is an example of any of the theories of spatial structures mentioned in the theoretical part of the thesis. In the theoretical part of the thesis are used methods of comparison and literary research. For the practical part of the thesis, analysis and tools Excel and ArcGIS are used, specifically its programs ArcGIS Pro and ArcGIS Online, as well as econometric statistical software Gretl and as an additional tool for the practical part is used questionnaire survey. Data for the addresses of Prague apartments are downloaded from the database INEM.cz, for nature parks and entrances to the metro, public data from the Geoportal of the Capital City of Prague are used. The added value of the work is the acquisition of data from the database of the INEM.cz and from the Geoportal of the Capital City of Prague and their analysis, compilation of maps and analysis of data from the Econometric software Gretl and comparison of the results obtained in this way with the results of the questionnaire survey. The aim of the work was met, the hypothesis was verified: With the increasing distance to the center of Prague, the price of Prague apartments decreases. The analysis showed that all these factors influenced the price of a Prague apartment in 2020 and are statistically significant. The questionnaire survey showed that people would be willing to pay for a closer distance to greenery and public transport.Bakalářská práce se zabývá otázkou, jak byly ovlivněny ceny pražských bytů vzdáleností do centra v roce 2020. Hlavním cílem práce je potvrdit hypotézu: S rostoucí vzdáleností do centra Prahy se cena pražských bytů snižuje. Dalším cílem práce je zjistit, zda alternativní faktory jako blízkost přítomnosti městské zeleně a zastávek městské hromadné dopravy měly vliv na cenu pražských bytů v roce 2020. Posledním cílem je ověření, zda je město Praha příkladem některé z teorií prostorových struktur uvedené v teoretické části práce. V teoretické části práce jsou použity metody srovnávání a literární rešerše. Pro praktickou část práce je využita analýza a nástroje Excel a ArcGIS, konkrétně jeho programy ArcGIS Pro a ArcGIS Online, dále ekonometrický statistický software Gretl a jako doplňující nástroj pro praktickou část je použito dotazníkové šetření. Data pro adresy pražských bytů jsou stažena z databáze INEM.cz, pro přírodní parky a vstupy do metra jsou použita veřejná data z Geoportálu hlavního města Prahy. Přidanou hodnotou práce je získání dat z databáze INEM.cz a z Geoportálu hlavního města Prahy a jejich analýza, sestavení map a analýza údajů z ekonometrického softwaru Gretl a porovnání takto získaných výsledků s výsledky dotazníkového šetření. Cíl práce byl splněn, byla verifikována hypotéza: S rostoucí vzdáleností do centra Prahy se cena pražských bytů snižuje. Z analýzy vyplynulo, že všechny zmíněné faktory ovlivnily v roce 2020 cenu pražského bytu a jsou statisticky signifikantní. Z dotazníkového šetření vyplynulo, že by lidé byli ochotni platit za bližší vzdálenost k zeleni a MHD

Gain stabilization of SiPMs

The gain G of SiPMs depends both on bias voltage and on temperature. For stable operation in large detector systems, gain needs to be kept constant. This can be achieved by readjusting the bias voltage with temperature. We have built an adaptive bias voltage regulator (ADApower) that uses a linear algorithm to adjust the bias voltage V if the temperature T changes. We determined the V(T) dependence from measurements of the gain-versus-temperature dependence (dG/dT) for different bias voltage and the gain-versus-bias-voltage dependence (dG/dV) for different temperatures in a climate chamber SpiraB at CERN. We tested and studied 30 pieces of SiPM in groups of six types in temperature range of 5 to 40° C and found that the gain stabilization works excellently (<;1%

Cyclic deformation behaviour and stability of grain-refined 301LN austenitic stainless structure

Low cycle fatigue (LCF) behaviour of metastable austenitic 301LN stainless steel with different grain sizes – coarse-grained (13 μm), fine-grained (1.4 μm) and ultrafine-grained (0.6 μm) – produced by reversion annealing after prior cold rolling was investigated. Fully symmetrical LCF tests with constant total strain amplitudes of 0.5% and 0.6% were performed at room temperature with a low constant strain rate of 2×10-3 s-1. Microstructural changes in different positions within the gauge part of the specimens were examined by optical microscopy (polarized light) and electron backscatter diffraction (EBSD) technique; for quantitative assessment of the volume fraction of deformation induced martensite (DIM) a Feritscope FMP 30 was adopted. The cyclic stress-strain response and specific changes of hysteresis loop shapes in the very early stage of cycling are confronted with the character of DIM formation and its distribution in the whole volume of the material. A possible effect of strain rate (frequency of cycling) on the destabilization of austenitic structure during cyclic straining of materials with different grain sizes is highlighted

Cyclic deformation behaviour and stability of grain-refined 301LN austenitic stainless structure

Abstract Low cycle fatigue (LCF) behaviour of metastable austenitic 301LN stainless steel with different grain sizes — coarse-grained (13 μm), fine-grained (1.4 μm) and ultrafine-grained (0.6 μm) — produced by reversion annealing after prior cold rolling was investigated. Fully symmetrical LCF tests with constant total strain amplitudes of 0.5% and 0.6% were performed at room temperature with a low constant strain rate of 2×10⁻³ s⁻¹. Microstructural changes in different positions within the gauge part of the specimens were examined by optical microscopy (polarized light) and electron backscatter diffraction (EBSD) technique; for quantitative assessment of the volume fraction of deformation induced martensite (DIM) a Feritscope FMP 30 was adopted. The cyclic stress-strain response and specific changes of hysteresis loop shapes in the very early stage of cycling are confronted with the character of DIM formation and its distribution in the whole volume of the material. A possible effect of strain rate (frequency of cycling) on the destabilization of austenitic structure during cyclic straining of materials with different grain sizes is highlighted

International Large Detector: Interim Design Report

The ILD detector is proposed for an electron-positron collider with collision centre-of-mass energies from 90~\GeV~to about 1~\TeV. It has been developed over the last 10 years by an international team of scientists with the goal to design and eventually propose a fully integrated detector, primarily for the International Linear Collider, ILC. In this report the fundamental ideas and concepts behind the ILD detector are discussed and the technologies needed for the realisation of the detector are reviewed. The document starts with a short review of the science goals of the ILC, and how the goals can be achieved today with the detector technologies at hand. After a discussion of the ILC and the environment in which the experiment will take place, the detector is described in more detail, including the status of the development of the technologies foreseen for each subdetector. The integration of the different sub-systems into an integrated detector is discussed, as is the interface between the detector and the collider. This is followed by a concise summary of the benchmarking which has been performed in order to find an optimal balance between performance and cost. To the end the costing methodology used by ILD is presented, and an updated cost estimate for the detector is presented. The report closes with a summary of the current status and of planned future actions