University Of Prague Research Articles

Zwischen Anspruch und Wirklichkeit: eine Einordnung der europapolitischen Grundsatzrede des deutschen Bundeskanzlers

On 29 August 2022, German Chancellor Olaf Scholz gave a long-awaited speech at Charles University in Prague that provides an important point of reference for the future European policy course of the incumbent coalition government after 16 years of Angela Merkel - and the yardstick by which it will have to be measured. Against the background of the Russian aggression against Ukraine, the speech was also an attempt to spell out the “Zeitenwende” - the historic turning point for German foreign policy - in more detail and to translate it to the European level. At the same time, Scholz aimed to address recent criticism by its European partners over Germany’s support to Ukraine and make the case for European unity - yet, reservations remain.

Tests of Glass Insulating Panels with Embedded Laminated Point Connections

Embedded laminated point connections represent a progressive way of glass structures connecting. However, detail information about their performance is not available yet and the design procedure is mostly based on experimental work and previous experience of designers. Within an ongoing research at the Faculty of Civil Engineering of the Czech Technical University in Prague, a set of real-scale insulating glass panels with embedded laminated point connections was tested. The goal of the experiment was to determine the load bearing capacity and characteristics of this type of glass panel under short-term and long-term loads. There were three different types of panels used for the experiment. The specimens consisted of different combinations of glass plies (ESG, TVG) and plies of different thicknesses. However, all the specimens were identically sized and there was one embedded steel countersunk bolt liners in each panel’s corner. The laminated glass plies were bonded by two layers of an EVA foil in all cases. During the experiment, all the samples were placed horizontally using the embedded point connections. The applied load was gradually increasing until the collapse. Vertical deflections in specific points of the samples were measured. The temperature and the humidity were monitored as well.

Development of a 10 kW class axial impulse single stage turboexpander for a micro-CHP ORC unit

Development of micro ORC systems with 1-15 kW power output for micro-cogeneration and waste heat recovery at the Czech Technical University in Prague, University Centre for Energy Efficient Buildings (CTU UCEEB) has over ten years of history with many successes. These include 6 different ORC units, all with in-house designed rotary vane expanders (RVE) of many versions throughout this development. Among main advantages of the RVE belong relatively simple and robust design at low cost even at very small series of single-unit production and all that with acceptable efficiency. The ORC units operate with hexamethyldisiloxane (MM) working fluid at high pressure ratios and expansion ratios and the isentropic efficiency of RVE has a limit at these conditions around 60%, often however only at values around 50%. While this might be enough on a cost side for commercialization of this technology, in pursuit of higher efficiency solutions, different expander technology needs to be selected. A turbo-expander is a logical choice with prospect of higher efficiency. At the same time, a literature review has found a lack of reported detailed experimental data for micro (5-50 kW) turbo-expanders, possibly hindering global development towards economically feasible solutions. A project named Dexpand, “Optimised expanders for small-scale distributed energy systems” aims at these issues by objectives in designing, optimizing, manufacturing and testing several ORC expanders with MM and isobutane and their subsequent performance mapping and comparison. One major task is a design of a turboexpander for a 120 kWth biomass fired microcogeneration ORC unit currently operated at the CTU UCEEB. An axial impulse single stage turboexpander was selected as a suitable choice, providing a prospect of a decent efficiency at technically manageable rotational speed and size. This paper provides a detail of currently performed design activities, starting from boundary conditions specification, over development and optimization of a 1D model, preliminary 2D CFD calculations and finishing in a state of a robust and detailed 3D CFD model with a real gas model. Note that the working fluid, high molar mass organic vapour, is highly non-ideal in its behaviour and the flow conditions with pressure design ratio around 13 is highly supersonic (nozzle outlet isentropic Mach number exceeds 2). The current results based on 3D CFD indicate a prospect of an isentropic efficiency 71% at mechanical power output of 11 kW. Lastly, ongoing and future work is outlined, which includes aerodynamic optimization based on the developed 3D CFD model and construction design of the entire turbine assembly.

Filozofia a svetonázor v recepcii členov slovenského spolku „Detvan“ v Prahe do roku 1900

At the turn of the 19th and 20th centuries, ideological differences began to emerge in the Slovak national movement under the influence of intellectual stimuli to which the younger generation of the Slovak intelligentsia was exposed during their university studies. The Detvan association, which brought together Slovak students in Prague, created opportunities for ideological transfer, including the fields of philosophy and worldview. This paper’s aim is to identify the ideas developed by European intellectuals and the ideological currents that became the subject of discussions at the association’s meetings, influencing the thinking of Detvan’s members. In addition to publications aimed at the public at large, important sources documenting the ideological inspirations and the formation of opinions by the Detvan members, this paper includes the minutes of the internal meetings of the association, kept at the archives of Charles University in Prague. The analysis of these minutes has shown that, until 1900 and especially in the 1890s, the self-education of the members was to a significant extent also aimed at expanding their knowledge of philosophy, expected to serve as a springboard for the formation of political thinking and perception of the world. Themes of the papers the members presented and discussions held in the association included the work and thought of Charles Darwin, Immanuel Kant, Ernest Renan, Tomáš G. Masaryk, Arthur Schopenhauer as well as Karl Marx and Friedrich Engels. The members also discussed ideas expressed in the fiction of writers Leo Tolstoy, Émile Zola, Henrik Ibsen and H. G. Wells. At the turn of the 19th and 20th centuries, the younger generation of the Slovak intelligentsia was thus exposed to the ideas of the labour movement and socialism, female emancipation, Darwinism, positivism, naturalism and secularisation. The association offered a platform for the transfer of ideas whose freedom contrasted with the formal and predominantly conservative character of the official university milieu in Prague. Among the most active Detvan members in the 1890s, who contributed their own lectures, papers and reflections, were Ján Smetanay, Vavro Šrobár and Jozef Ruman. After their departure, the focus of the association’s self-education began to shift to national history and literature, lectures on Slovak grammar and literary criticism.

Application of the single-engine taxi-out procedure for commercial transport, focusing on the Airbus A320 fleet

There is currently a lot of pressure on airlines to reduce emissions, noise and fuel consumption. Another aspect is the drive to reduce operating costs, which leads to investment into the new technologies and also to the introduction of new procedures. One of these procedures is the so-called 'Single-engine Taxi-out', which aims to save fuel during taxiing. Together with this, the costs for the entire flight are reduced. Research at the department of Air Transport at the Faculty of Transportation Sciences of the Czech Technical University in Prague is underway to reduce the financial costs and emissions produced during each flight. One successful solution is to reduce emissions and the associated cost by using single-engine taxi procedures.

Evropské paralely pro scestí a selhání federalistického myšlení v prostoru bývalého Československa

This paper is based on Constantin Frantz’s concept of a true “federation for citizens”. Frantz’s concept has been misunderstood and neglected by a large part of the persons involved in constitutional thinking in the mid 19th century Bohemia and Upper Hungary, that is, the territories of today’s Czech and Slovak Republics. The result of that neglect and misunderstanding was delusion. The Czech Faculty of Law at Charles University in Prague became a stronghold of dogmatic centralist thinking; it found itself in conflict with other university faculties in interwar Czechoslovakia. With the take over of the Communist Party in February 1948, critical federalist thinking vanished, as a result of government domestic policy. After August 1968, critical federalist thinking as a concept of federation ceased to exist, since the concept ‘federation’ was bereft of its true sense. This resulted in the painful lack of understanding of the inherent problems of federalism and decentralisation in the early 1990s.

Modelling of multiphase solid-liquid laminar flow with non-Newtonian carrier in pipelines using a layered model

This paper discusses two-phase laminar flows of mixtures of solids in non-Newtonian carrier consisting of spherical particles in a 50-mm pipe at the Czech Technical University in Prague. Special attention is paid to the frictional head loss and thickness of transport layers. For the prediction of various transport characteristics, a layered model is used. Suitability of the layered model to predict the transport characteristics is investigated. Prediction results are compared to own experimental data.

Polemika Josefa Truhláře s Václavem Flajšhansem o soupisu Husova díla

The paper deals with the controversy over the catalogue of the writings of Jan Hus between Josef Truhlář (1840–1914), a curator of the Prague University Library, and Václav Flajšhans (1866–1950), a high-school professor, which took place from 1898 until 1905. The latter had been preparing an inventory of the works of Jan Hus from 1898 (published in 1900), while the former had been working on the catalogue of Prague university manuscripts from 1897 (published in 1905/1906). They discussed the evidence of the extant manuscripts of the works of Jan Hus in detail. Especially the first phase of the controversy showed that Flajšhans wanted to present himself as a skilled scholar who could interpret Hus’s works in the context of contemporary national discourse and whose research was based on a close examination of manuscript sources. However, he encountered the incisive judgment and tenacity of Truhlář, who pointed out errors and shortcomings in Flajšhans’s works and fallacies in his polemical articles. Moreover, Truhlář sometimes resorted to certain simplifications, for example, regarding the number of the manuscripts discovered, and he also made minor mistakes, which he later openly admitted, as did Flajšhans in some cases. Nevertheless, the contribution of both scholars to the research on Jan Hus has been essential.

Diplomatic, Pedagogical and Scientific Activities of Stepan Smal-Stotsky in Czechoslovakia in 1918-1938

The article analyzes the activities of famous Ukrainian scientist and public figure Stepan Smal-Stotsky during his emigration to Czechoslovakia in 1918-1938. It is noted that now S.Smal-Stotsky had become a diplomat for the first time as the ambassador of the Western Ukraine People's Republic in Prague. In cooperation with the Ukraine People's Republic (UPR) embassy, he managed to implement a number of events to promote Ukrainian aspirations. From 1921 to 1937, S. Smal-Stotsky taught the Ukrainian Language and Literature at the Ukrainian Free University in Prague. There had been a lot of success in this field, he managed to educate an entire galaxy of eminent scientists in linguistics. The article notes that S. Smal-Stotsky was more concerned in scientific terms with the issues of the origin of the Ukrainian language, literary studies of the works of Taras Shevchenko at that time. He initiated a number of discussions on the issues of Ukrainian spelling, the ancient period of Ukrainian history. S. Smal-Stotsky out a great deal of organizational and social work at that time. He initiated two Ukrainian research and scientific congresses in Prague and headed the Museum of the Liberation Struggle of Ukraine.

Mongolian Studies in the Czech Republic: Personalities, Centers, Current State

Nowadays, improving international relations and strengthening international ties are leading trends in the development of world economy. In the epoch of globalization, both western and eastern countries are trying to promote close mutually profitable partnership relations between countries, because it can serve as a trigger for their further gradual development. As it can be observed in the practice, in the 21st century, the dialogue between the developed European countries and the actively developing East is becoming especially successful and efficient for both parties. One of the unique examples of the interest of the West towards the East is the development of Oriental and Mongolian studies in the Czech Republic. Its climax can be observed in the 20th century. The author of the article proves that contemporary Mongolian studies in the Czech Republic play a significant role in European Oriental studies. Analysis of the scientific contribution of the leading Czech specialists in Mongolian studies: P. Poucha, Lumir Iisl, Ya. Vacek, I. Shima, I. Grollova is conducted. A brief description of the current state of Mongolian studies in Charles University in Prague, the Czech Republic is given. The author draws a conclusion about the presence of scientific interest towards Mongolian linguistics and culture in Europe, which contributes to strengthening cultural identity of Mongolia. On the basis of continuity of research and the presence of an original scientific school of Mongolian studies in the Czech Republic, the author makes an assumption about the possibility of extending research of the issues of economy and economic geography of Mongolia, which will, undoubtedly, contribute to strengthening the relations between the countries.

Před 50 lety zemřel akademik Antonín Přecechtěl

Antonín Přecechtěl was born on 6 November 1885 in the village of Srbce in the Prostějov region (Moravia) in a peasant’s family. He graduated from the secondary grammar school in Kroměříž and studied medicine at the Czech Medical Faculty of the Charles-Ferdinand University in Prague. After graduating in 1910, he started his career as a surgeon at prof. Kukula’s surgery clinic in Prague. As a surgeon, he participated in the Balkan Wars and the First World War. In 1918 he began to work at prof. Kutvirt’s ear clinic in Prague. Here he obtained habilitation in otology and pharyngology in 1920, and in 1924 he was appointed associate professor. After Kutvirt’s death, he became the head of the clinic in 1930, and in the same year, he also received habilitation in rhino-laryngology, thus completing the process of unifying the teaching of otorhinolaryngology as one field. He held the position of head of the Otolaryngology Clinic for 30 years. He was a founding member of the Czech Otolaryngological Society (1921) and in the period 1935–1951, he was its chairman. In 1926, as a founding member, he participated in the founding of the prestigious organization Collegium Oto-Rhino-Laryngologicum Amicitiae Sacrum. He also participated in the establishment and management of the international journal Otolaryngologia Slavica, and the journal Czechoslovak Otolaryngology began to be published in 1952 on his initiative. The results of his scientific work have been published in almost 400 publications in both domestic and foreign journals. Přecechtěl was also involved in laboratory and experimental research, especially on the vestibular apparatus. In 1954 he was appointed a full member of the Czechoslovak Academy of Sciences, in which he founded the Otolaryngological Laboratory. Professor Přecechtěl created his own otorhinolaryngology school and trained many experts. He died on 5 February 1971, at the age of 85. Keywords: history – Antonín Přecechtěl – remembrance – commemoration – Czech otorhinolaryngology – ENT

The project of VR-2 subcritical assembly

The paper describes the project of VR-2 Subcritical assembly (SCA) which is being developed and built at the Czech Technical University in Prague (CTU). VR-2 SCA is to be placed in a building of already established facility of VR-1 Training reactor which has been successfully operated by CTU since 1990.CTU has decided to build the new nuclear facility (VR-2 SCA) even though it already operates one (VR-1 Training reactor). The main motivation is a worldwide large demand for education and training at nuclear research facilities. Currently, VR-1 Training reactor is reaching its maximum capacity, especially during a semester when the utilization reaches almost 100%. It is expected VR-2 SCA provides additional capacity for training and education in a field of nuclear engineering and enhances research possibilities at CTU. Interesting areas of research that could be addressed at the VR-2 reactor are: benchmark experiments, criticality safety studies, studies of accelerator driven systems and development/testing of radiation detection systems.VR-2 SCA is designed as an open pool vessel including a water-moderated uranium core. The core will consist of a combination of an enriched and natural uranium fuel. The SCA will be driven by a D-D neutron generator. The generator can operate in both continuous and pulse mode, and thus allowing pulse neutron source experiments. The facility keeps a high level of flexibility where many parameters can be changed, e.g. geometry of a core lattice, moderator temperature, water level etc.

The state of hospitals in Pidkarpatska Rus during the first decade of czechoslovak rule (1919-1929)

The article traces the process of activity of hospitals in Transcarpathia during the first decade of the land being a part of Czechoslovakia. Research methods. First of all, comparative-historical and structural-system methods of analysis, generalization and synthesis, as well as problem-chronological way of presenting the material have been used. Scientific novelty. The outlined problematics is considered in historiography for the first time. Conclusions. It is noted that at the time of the incorporation of Transcarpathia into Czechoslovakia there were four county hospitals, three of which were in a rather deplorable condition. The Czechoslovak administration had to make considerable efforts to modernize them. Emphasis was placed on the activities of doctors who came to Transcarpathia mainly from the Czech and Moravian lands. They were usually graduates of the Medical Faculty of the University of Prague, and some even underwent internships at leading European clinics. It is thanks to their ascetic work that the condition of hospitals and medical care of the population had improved.

LITTLE-KNOWN PAGES OF IVAN MYKHAYLOVYCH TRUBA’S LIFE AND ACTIVITY (1878−1950 to the 140th anniversary of the birth and to the 91st anniversary of the founding of the SHEI “Pryniprovska State Academy of Civil Engineering and Architecture”)

Formulation of the problem. The hitherto little-known parts of the way of life, teaching andarchitectural and construction activities in the CPC (Ekaterinoslav Technical Courses) are covered. Korobochkin(famous Ukrainian public figure I.M.Truba) (1878−1950); the history of creation of these COURSES, their purpose,personnel of courses, the program of training, its change during the first two years with aspiration to approach toprograms of similar higher Western European countries, surnames of teachers on subjects is added. Brief service andcreative characteristics of teachers for the entire period of the COURSES. By the way, a unique photo of the newbuilding of V.K. Korobochkin's Ekaterinoslav Technical Courses was added to the article, preserved in the author'sarchive, but it was built under the direction of I.M. Truba, according to his project and estimate. Its facade is described.The significance of V.K. Korobochkin’s Ekaterinoslav Technical Courses for the whole of the Dnieper, as the embryoof all technical universities, and later the National University, is given, the advantage of the Courses in this sense isproved. This is documented. In exile, I. M. Truba continues educational and pedagogical activities for the benefit of theMotherland − translates into Ukrainian, highly moral, in the educational sense, fairy tales by European authors,publishes them and sends them to Ukrainian schools. Corresponds with his children to Dnіpropetrovsk, givesinstructions. As an example of his drawing skills, he cites drawings, in 3D-style pencil, of the corners of his homes inexile. Mention is made of his entrance examinations at the Higher School in St. Petersburg, including the Academy ofArts. He also works at Florinsdorfen Lokomotivfabrik and at the architectural and construction company Hestia. Since1924, when he was invited to Czechoslovakia, he has been working as a lecturer at the Ukrainian Academy ofEconomics at the Faculty of Agriculture in Podebrady , reads courses on machine parts, and Resistance materialsaccording to his own textbook, which he compiled in Ukrainian and published at the Academy. On the recommendationof an engineer, Doctor of Technical Sciences, Rector of the Higher Technical University in Prague, Professor ZdenekBazant [20], in 1929 Ivan Mikhailovich Truba was hired as a design engineer and general consultant in the bridge andiron production department of the Skoda Plant. In the city Pilsen. Documents testify to his highly skilled engineeringand creative activity. The list of types of constructive projects executed by I.M. Truba at the enterprise and implementedis given. The chronology in the field of creativity, the era of the Central Council and emigration has been clarified, hisscientific publications and pedagogical and creative activity as a scientist have been added The purpose of the article isto supplement the monograph on the life and work of I.M. Truba and its surroundings. Conclusions. It is known thatduring the Bolshevik rule, in his homeland, Ivan Mikhailovich was considered an enemy of the people (which was notspecified) "as a Ukrainian bourgeois nationalist". Therefore, all his activities were subjected to political anathema.Researched and analyzed archival materials, on the basis of which the conclusion is given − the significance ofI.M. Truba is covered as a person, a citizen − a patriot, namely: the UKRAINIAN PEOPLE. Ivan Mikhailovich'sactivity during his lifetime was distinguished by its versatility, namely: pedagogy, education, political, cultural andsocial activities, national patriotism, writing, architectural construction and scientific creativity.

Is It Better to Start Treatment with ABVD and Continue with PET2-Adapted Approach or Should We Use 2 Cycles of Beacopp Escalated and 2 Cycles of ABVD and Irradiation in Early Unfavorable Hodgkin Lymphoma?

Introduction. EORTC H10 trial confirmed better selection of patients who needed reduced or more intensive treatment using PET response after 2 cycles of ABVD in early stages of classical Hodgkin lymphoma (cHL). GHSG HD17 showed that radiotherapy can be safely omitted in PET4-negative early unfavorable HL treated with 2 cycles of BEACOPP escalated plus 2 cycles of ABVD (2+2 chemotherapy). We compared PET2-adapted approach including 30Gy involved-node radiotherapy (INRT) with 2+2 chemotherapy followed by 30 Gy INRT (or involved-field radiotherapy, IFRT) regardless of interim PET in patients with early unfavorable cHL assessed according to the GHSG risk factors.Methods. Overall 243 patients with early unfavorable cHL (aged 18-60 years) prospectively observed in the Czech Hodgkin lymphoma study group registry between 2003-2020 were analyzed. Patients in clinical stage IIB with massive mediastinal tumor and/or with extranodal disease were not included into this analysis as they were treated with BEACOPP escalated only. Chemotherapy 2+2+30 Gy INRT/IFRT received 213 patients. Overall 30 patients were treated with PET2-adapted approach: 29 PET2-negative patients received 4 cycles of ABVD and 30 Gy INRT and one PET2-positive patient was treated with 2 cycles of ABVD plus 2 cycles of BEACOPP escalated and 30 Gy INRT.Results. Median age at the time of cHL diagnosis was 32 (range 18-59) years. Median follow-up was longer in the 2+2+INRT/IFRT group (91.3, range 6.2-211.2) months when compared to the PET2-adapted approach (19.4, range 6.4-90.4) months. The estimated 2-year progression-free survival (PFS) did not differ in both groups (100% [95% CI 100-100] both), however, the estimated 5-year PFS was significantly better in the 2+2+INRT/IFRT group (99.5% [95% CI 98.5-100]) in comparison to PET2-adapted treatment (75.0% [95% CI 32.5-100]), p<0.001. The estimated 5-year overall survival was comparable in both groups (2+2+INRT/IFRT: 99.5% [95% CI 98.5-100]; PET2-guided treatment: 100% [95% CI 100-100]). Hematological toxicity was reported in most of the patients in both groups. Grade 3 non-hematological toxicity occured in 3 patients in the 2+2+INRT/IFRT approach (2 infections, 1 deep vein thrombosis).Conclusion. This retrospective analysis indicates that 2+2+INRT/IFRT is more effective in the long-term disease control, but there is no difference in overall survival in both groups. The current approach includes 2+2 chemotherapy and INRT is added in PET4-positive patients.This work was supported by the Research project Q 28 Progres awarded by the Third Faculty of Medicine of Charles University in Prague in the Czech Republic. DisclosuresBelada: Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: travel expenses, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding; Celgene: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses, Research Funding.

Výuka ekumeniky v rámci praktické teologie na pražské evangelické fakultě. Odkaz Josefa Smolíka a Pavla Filipiho

Teaching ecumenics within practical theology at the Prague protestant faculty: The legacy of Pavel Filipi and Josef Smolík The article deals with the development of teaching about ecumenical issues at the Protestant Theological Faculty of Charles University in Prague since its foundation in 1919 and its gradual linking with the teaching of practical theology. This connection is largely a legacy of two faculty professors of practical theology, Josef Smolík (1922–2009) and Pavel Filipi (1936–2015).

Simple Laminated Glass Panels with Embedded Point Connection under Short-Term Load

Glass is a very attractive material for contemporary architecture. The trend is to achieve a maximum transparency of structures; therefore it becomes common to use glass as a material for load-bearing structural elements. Glass facades, roofs, beams or columns are widely used in buildings. The problematic part of a glass structure design is the connection between the glass pieces or between the glass elements and substructures from another material (e.g. steel, concrete etc.). The connection must be capable of bearing the stresses performing during the lifetime period and it should be as unobtrusive as possible at the same time. The ongoing research at the Faculty of Civil Engineering of the Czech Technical University in Prague is focused on an embedded laminated point connection for glass structures. Within this research, the real-scale glass panels were tested. The samples consisted of two glass plies bonded with the EVA foil. For the undrilled ply, the float glass was used in all cases. The thermally toughened or the heat strengthened glass was used for the pre-drilled ply. There was one embedded steel countersunk bolt with HDPE liners placed in each corner of the sample. During the experiment, the samples were horizontally placed using the embedded bolts. The load-bearing capacity of the six tested specimens was determined. The load was applied in several loading and unloading cycles until the collapse of the first embedded connection. If the glass panel failed before the connection, the sample was completely unloaded and then the load was gradually increasing until the collapse of the connection. Vertical deflection and the stresses at two different points were measured during the loading cycles. The humidity and the temperature were also monitored. The experiment showed the way of collapse and a short-term load-bearing capacity of a laminated glass panel with four embedded point connections.

Effect of Energy Dissipation on Scour Hole Development Downstream of the Chute

An energy dissipation on hydraulic structures is a scientifically highly examined field of study. Gained knowledge can be used to ensure the safety of the hydraulic structures and the channels which is crucial during floods. Above that, those structures are also part of the critical infrastructure therefore their function is necessary. It is assumed that in the Czech Republic the precipitation distribution is changing due to climate change thus episodes of extreme floods may be observed more often. The paper brings brand new knowledge on the kinetic energy dissipation on the chute and in the stilling basin and its impact on the riverbed scour hole development. The presented research was conducted in the Water Management Experimental Centre of Czech Technical University in Prague, Faculty of Civil Engineering. The research aimed to examine the energy dissipation mechanism on different geometric modifications of the construction of spillway chute and stilling basin and its impact on the process of scour hole development. These various types of dams’ flood safety equipment were examined in the hydraulic laboratory: an elementary form of the spillway without any stilling basin; the elementary form of the spillway and the stilling basin (crest and spillway channel had the same width); the chute width was reduced, and the stilling basin had the full width; steps were added on the narrowed chute and the and stilling basin had the full width; only the spillway crest was reduced to a half-width; only the stilling basin width was smoothly reduced; the chute’s width was smoothly reduced along the chute and the stilling basin had full width; the chute’s width was smoothly reduced along the chute and the stilling basin had the width reduced to a half. The flow, water levels, scour hole and deposit dimensions were measured. Then the amount of energy dissipated was computed. The correlation and connection between energy dissipation and scour hole development was investigated. These outcomes can be used as a recommendation of an appropriate construction design to provide better flood safety of the hydraulic structure.

The 1804 examination for the chair of Elementary Mathematics at the University of Prague

In 1804 the chair of Elementary Mathematics at Prague University became vacant and a selection procedure, which consisted of a written and an oral examination, was announced. Only Bernard Bolzano and Ladislav Jandera took part in it. Jandera was appointed to the chair, whereas Bolzano became Professor of “Religious Doctrine.” In this paper we examine the context of this Concursprüfung, the performance of both candidates and the outcome, based on a number of related papers preserved at the Czech National Archives. In addition to this, we publish for the first time, albeit only in the online version of this paper, the transcription and English translation of Bolzano's written examination.

Sulfint – the Czech gas desulfurization technology

The article describes one of the gas desulphurisation technologies which has been developed in the Czech Republic. The technology uses washing solution of organic complexes of various metals to remove H2S from gases. H2S removal is realized by its reaction with complexes of suitable metals with organic reagents. This leads to the H2S oxidation to elemental sulfur and the reduction of the metal protected by the organic complex to a lower oxidation state, which is also bound in the organic complex. Regeneration of the washing solution is performed by oxidation of the reduced form of the complex using oxygen from the air. Complexes of iron with ethylenediaminetetraacetic acid, nitrile triacetic acid or diethylenetriaminopentaacetic acid are used for the preparation of washing solutions. The reaction of the ferric complex of ethylenediaminetetraacetic acid with H2S is accompanied by a change in the color of the washing solution from a deep red color (like red wine) to a light brown color (like coffee with milk) of the ferrous complex of ethylenediaminetetraacetic acid. When this complex is completely depleted, it begins to decompose to black ferrous sulfide by further contact with H2S. This reaction is irreversible. The ferrous complex of ethylenediaminetetraacetic acid can be regenerated by reaction with oxygen, which also takes place at normal or elevated temperatures. The rate of this reaction is much slower compared to the reaction of H2S with the ferric complex. The process was discovered and intensively researched at the Institute for Fuel Research in Prague and later also at the University of Chemistry and Technology Prague. The first pilot plant tests took place with the desulfurization of coke oven gas at the Coking Plant Vítězný únor in Ostrava, where the first operating facility working with the given technology was later built. Another operating facility working with this technology was put into operation at the Antonín Zápotocký High pressure gasification plant in Ústí nad Labem and was used for desulphurization of expansion gases from pressure purification of waste gas of the Rectisol system. The technology was named Sulfint. Both facilities operated successfully until the end of operation of the town-gas supply system in the Czech Republic in the mid-1990s.