Measurement of aerodynamic and acoustic quantities describing flow around a body placed in a wind tunnel

Aerodynamically generated noise affects passenger comfort in cars, high-speed trains, and airplanes, and thus, automobile manufacturers aim for its reduction. Investigation methods of noise and vibration sources can be divided into two groups, i.e. experimental research and mathematical research. Recently, owing to the increase in computing power, research in aerodynamically generated noise (aero-acoustics) is beginning to use modem methods such as computational fluid dynamics or fluid-structure interaction. The mathematical model of turbulent flow is given by the system of partial differential equations, its solution is ambiguous and thus requires verification by physical experiment. The results of numerical methods are affected by the boundary conditions of high quality gained from the actual experiment. This article describes an application of complex measurement methodology in the aerodynamic and acoustic (vibro-acoustic) fields. The first part of the paper is focused on the specification of the experimental equipment, i.e. the wind tunnel, which was significantly upgraded in order to obtain the relevant aerodynamics and vibro-acoustics data. The paper presents specific results from the measurement of the aerodynamic and vibro-acoustic fields.Web of Science191282

Search for Wieferich Primes through the use of Periodic Binary Strings

The result of the distributed computing projectWieferich@Home is presented: the binary periodic numbers of bit pseudo-length j ≤ 3500 obtained by replication of a bit string of bit pseudo-length k ≤ 24 and increased by one are Wieferich primes only for the cases of 1092 or 3510

The Beaker phenomenon and the genomic transformation of northwest Europe

From around 2750 to 2500 bc, Bell Beaker pottery became widespread across western and central Europe, before it disappeared between 2200 and 1800 bc. The forces that propelled its expansion are a matter of long-standing debate, and there is support for both cultural diffusion and migration having a role in this process. Here we present genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, including 226 individuals associated with Beaker-complex artefacts. We detected limited genetic affinity between Beaker-complex-associated individuals from Iberia and central Europe, and thus exclude migration as an important mechanism of spread between these two regions. However, migration had a key role in the further dissemination of the Beaker complex. We document this phenomenon most clearly in Britain, where the spread of the Beaker complex introduced high levels of steppe-related ancestry and was associated with the replacement of approximately 90% of Britain’s gene pool within a few hundred years, continuing the east-to-west expansion that had brought steppe-related ancestry into central and northern Europe over the previous centuries

Stone Age Yersinia pestis genomes shed light on the early evolution, diversity, and ecology of plague

[Significance] The bacterium Yersinia pestis has caused numerous historically documented outbreaks of plague and research using ancient DNA could demonstrate that it already affected human populations during the Neolithic. However, the pathogen’s genetic diversity, geographic spread, and transmission dynamics during this early period of Y. pestis evolution are largely unexplored. Here, we describe a set of ancient plague genomes up to 5,000 y old from across Eurasia. Our data demonstrate that two genetically distinct forms of Y. pestis evolved in parallel and were both distributed across vast geographic distances, potentially occupying different ecological niches. Interpreted within the archeological context, our results suggest that the spread of plague during this period was linked to increased human mobility and intensification of animal husbandry.The bacterial pathogen Yersinia pestis gave rise to devastating outbreaks throughout human history, and ancient DNA evidence has shown it afflicted human populations as far back as the Neolithic. Y. pestis genomes recovered from the Eurasian Late Neolithic/Early Bronze Age (LNBA) period have uncovered key evolutionary steps that led to its emergence from a Yersinia pseudotuberculosis-like progenitor; however, the number of reconstructed LNBA genomes are too few to explore its diversity during this critical period of development. Here, we present 17 Y. pestis genomes dating to 5,000 to 2,500 y BP from a wide geographic expanse across Eurasia. This increased dataset enabled us to explore correlations between temporal, geographical, and genetic distance. Our results suggest a nonflea-adapted and potentially extinct single lineage that persisted over millennia without significant parallel diversification, accompanied by rapid dispersal across continents throughout this period, a trend not observed in other pathogens for which ancient genomes are available. A stepwise pattern of gene loss provides further clues on its early evolution and potential adaptation. We also discover the presence of the flea-adapted form of Y. pestis in Bronze Age Iberia, previously only identified in in the Caucasus and the Volga regions, suggesting a much wider geographic spread of this form of Y. pestis. Together, these data reveal the dynamic nature of plague’s formative years in terms of its early evolution and ecology.This study was funded by the Max Planck Society, Max Planck Harvard Research Center for the Archaeoscience of the Ancient Mediterranean and the European Research Council under the European Union’s Horizon 2020 research and innovation program under Grant Agreement 771234 – PALEoRIDER (to W.H.), 856453 – HistoGenes (to J.K.), and 834616 – ARCHCAUCASUS (to S.H.). The Heidelberg Academy of Science financed the genetic and archeological research on human individuals from the Augsburg region within the project WIN Kolleg: “Times of Upheaval: Changes of Society and Landscape at the Beginning of the Bronze Age. M.E. was supported by the award “Praemium Academiae” of the Czech Academy of Sciences. M.D. was supported by the project RVO 67985912 of the Institute of Archaeology of the Czech Academy of Sciences, Prague. I.O. was supported by the Ramón y Cajal grant from Ministerio de Ciencia e Innovación, Spanish Government (RYC2019-027909-I). A. H€ubner was supported by the Deutsche Forschungsgemeinschaft under Germany’s Excellence Strategy (EXC 2051 – Project-ID 390713860). J.F.-E. and J.A.M.-A. were supported by the Diputación Foral de Alava, IT 1223-19, Gobierno Vasco. A. Buzhilova was supported by the Center of Information Technologies and Systems (CITIS), Moscow, Russia 121041500329-0. L. M., L.B.D., and E. Khussainova were supported by the Grant AP08856654, Ministry of Education and Science of the Republic of Kazakhstan. A. Beisenov was supported by the Grant AP08857177, Ministry of Education and Science of the Republic of Kazakhstan.Peer reviewe

Ten millennia of hepatitis B virus evolution

Hepatitis B virus (HBV) has been infecting humans for millennia and remains a global health problem, but its past diversity and dispersal routes are largely unknown. We generated HBV genomic data from 137 Eurasians and Native Americans dated between ~10,500 and ~400 years ago. We date the most recent common ancestor of all HBV lineages to between ~20,000 and 12,000 years ago, with the virus present in European and South American hunter-gatherers during the early Holocene. After the European Neolithic transition, Mesolithic HBV strains were replaced by a lineage likely disseminated by early farmers that prevailed throughout western Eurasia for ~4000 years, declining around the end of the 2nd millennium BCE. The only remnant of this prehistoric HBV diversity is the rare genotype G, which appears to have reemerged during the HIV pandemic

Copper in Eneolithic Bohemia

Univerzita Karlova v Praze Filozofická fakulta Ústav pro pravěk a ranou dobu dějinnou Miroslav Dobeš Měď v eneolitických Čechách Copper in Eneolithic Bohemia Disertační práce Abstract vedoucí práce - Doc. PhDr. Luboš Jiráň, CSc. 2012 Abstract Miroslav Dobeš: Copper in Eneolithic Bohemia. Copper artifacts are an important source of understanding for European prehistory, not only in terms of the development of new technologies, but also importantly as a means of social communication. The gradual perception of the copper objects from their initial importing to simple cold forging to pyrotechnological processes and culminating in the Early Bronze Age tin bronze alloys, can be observed already in the Near East at the end of the 9th Millenium B.C., in other words the Aceramic Neolithic (Çayönü Tepesi). Within Europe, there has been a rapid initial development of metalurgy in the Balkans, aproximatelly in the middle of the 5th Millenium B.C., in Central Europe this innovation has arrived sometime around 4000 B.C., or shortly afterwards. The present work is the first thorough analysis of the Czech Eneolithic copper industry, which is based largely on original documentation of findings and attempts to complete the synthesis of sources. From a chronological point of view, this work covers the entire period of the..

Návrh zařízení pro měření opakovačů

Import 20/04/2006Prezenční výpůjčkaVŠB - Technická univerzita Ostrava. Fakulta elektrotechniky a informatiky. Katedra (454) elektroniky a telekomunikační technik

Identification of the noise using mathematical modelling

In engineering applications the noisiness of a component or the whole device is a common problem. Currently, a lot of effort is put to eliminate noise of the already produced devices, to prevent generation of acoustic waves during the design of new components, or to specify the operating problems based on noisiness change. The experimental method and the mathematical modelling method belong to these identification methods. With the power of today’s computers the ability to identify the sources of the noise on the mathematical modelling level is a very appreciated tool for engineers. For example, the noise itself may be generated by the vibration of the solid object, combustion, shock, fluid flow around an object or cavitation at the fluid flow in an object. For the given task generating the noise using fluid flow on the selected geometry and propagation of the acoustic waves and their subsequent identification are solved and evaluated. In this paper the principle of measurement of variables describing the fluid flow field and acoustic field are described. For the solution of fluid flow a mathematical model implemented into the CFD code is used. The mathematical modelling evaluation of the flow field is compared to the experimental data

An Eneolithic inhumation graves from Holubice, Praha-západ district. On the Baden culture burial rite in Bohemia

Jeden z problémů středoevropského eneolitu představuje pohřební ritus badenské kultury, vcelku dobře dokumentovaný ve východní části jejího rozšíření a o to hůře v oblasti západní, kam spadají i Čechy. Předmětem předloženého příspěvku je prezentace prvních uspokojivě dokumentovaných kostrových hrobů ze jmenované oblasti, které byly prozkoumány v Holubicích, okr. Praha-západ. Práce přináší kromě zevrubného vyhodnocení nálezové situace a všech získaných pramenů též soubor radiokarbonových dat. Dále je v ní řešena detailní chronologická pozice hrobů a míra jejich podobnosti s projevy pohřbívání v jiných oblastech rozšíření badenského komplexu.One important issue in the central European Eneolithic is the Baden culture burial rite, which is documented quite well in the eastern part of its territory, though worse in the western region, including Bohemia. The subject of this article is the presentation of the first satisfactorily documented inhumation graves from the specified area investigated in Holubice in the Prague-západ district. In addition to a thorough evaluation of the find situation and all of the acquired sources, the article also provides a set of radiocarbon dates. The work establishes the detailed chronological position of the graves and the degree of their similarity to the manifestations of burials in other areas of the Baden complex

Výzkum podpory udržitelné výroby a spotřeby

Zpráva obsahuje souhrnnou zprávu k projektu. Je členěna podle jednotlivých fází řešení. Pro každou fázi obsahuje vedle stručné informace o jejích cílech také informaci o průběhu řešení projektu a o dosažených výstupech. Úplné výstupy řešení projektu jsou připojeny ke zprávě jako přílohy