Czech Technical University In Prague Research Articles

Problems with reinforced concrete industrial floors with regard to subsoil swelling

Most of the problems associated with open cracks in reinforced concrete industrial floors do not arise from technological indiscipline in the execution or exceeding the permitted floor load, but from the geotechnical profile beneath the floor. In the presence of swelling soil in the subsoil, the floors can then be shifted upwards by centimeters and create open cracks. This article describes regression relationships for the prediction of swelling pressure and deformation of reinforced concrete industrial floors based on indirect measurements. These relationships were obtained by evaluating a large database of measurements carried out by the company GeoTec-GS and the Czech Technical University in Prague using neural networks, multiple correlation, regression analysis, and sensitivity analysis. The article also presents the actual classification of the risk of surface damage of reinforced concrete floors due to swelling of the subsoil and an example of its application is given.

European Journal of Geography (Year 2023): Reviewer Appreciation & Publication Recap

Dear Readers, As we begin a new year full of potential and opportunity, we wish each of you much joy and success. As we embark on this journey, we al-so celebrate a significant milestone – the fifteenth anniversary of the European Journal of Geography. Over the past decade and a half, our journal has become a beacon of excellence in the field of geography and the social sciences. This journey has been characterised by unwavering commitment and tireless dedication, a collective endeavour led by the dedicated members of our editorial team and the European Association of Geographers (EUROGEO). Their diligence and passion have been instrumental in making our journal the respected publication it is today. Looking back on our shared history, we are proud to have published over 310 articles dealing with key topics in geography, planning and development. These scholarly contributions have not only explored and analysed important topics, but have also introduced new ideas (Kout-sopoulos, 2022; Manetos et al., 2022), methods (Cramer-Greenbaum, 2023; Krevs et al., 2023; Morawski & Wolff-Seidel, 2023) and data (Hojati & Mokarram, 2016) that will inspire future generations of geographers to transcend conventional disciplinary boundaries. The richness of our content encompasses numerous facets and includes the fields of geography education (Fraile-Jurado & Periáñez-Cuevas, 2023; Humble, 2023; Martínez-Hernández et al., 2023; Mašterová, 2023; Puertas-Aguilar et al., 2023), physical geography (Sánchez-Martínez & Cabrera, 2015), sustainability (Leininger-Frézal et al., 2023; Mally, 2021), tourism (Bandt et al., 2022; Jovanovic et al., 2022), geoin-formatics (Batsaris et al., 2023; Vestena et al., 2023), spatial analysis (Agourogiannis et al., 2021; Bartzokas-Tsiompras & Photis, 2020b; Wieland, 2022), remote sensing (Younes et al., 2023), maps (Nedkov et al., 2018; Papaioannou et al., 2020), geoinformation (Bartha & Kocsis, 2011; Bart-zokas-Tsiompras, 2022), economic (Doukissas et al., 2020; Mikhaylova, 2018), social (Mei & Liempt, 2022; Roșu et al., 2015), political (Kevicky, 2023; Tsitsaraki & Petracou, 2023) and cultural (Gusman & Otero-Varela, 2023) geography, geopolitics (Morgado, 2023) as well as environmental (Burić et al., 2023; Prodanova & Varadzhakova, 2022), urban (Chondrogianni & Stephanedes, 2021; Lagarias et al., 2022) and transport (Garrido, 2013; Kellerman, 2023; Koktavá & Horák, 2023) geography/planning (González, 2017). Each article, a testament to the diversity and depth of knowledge within our community, has played a crucial role in energising discourse in our academic environment. Several EJG articles addressed current global crises and challenges such as climate change, COVID-19, wars and economic recession. They show how important geography is when it comes to finding solutions and new insights to the many problems that threaten our world. This interconnected approach underlines the journal's commitment to engaging with both the specialised academic discourse and the broader global challenges of our time. Authors, editors, board members, reviewers and readers are the lifeblood of this academic platform, and we recognise and appreciate your invaluable role in the success of the European Journal of Geography. Your commitment has fuelled our growth and you are an essential part of our legacy. We take our fifteenth anniversary as an opportunity to invite and encourage you to contribute to the continued success of the journal by submitting new and original geographical research articles. Here's to another year of scholarly work, meaningful collaborations and the continued advancement of geographical knowledge. We would also like to take a moment to recognise the incredible efforts of 95 professors and researchers who served as reviewers for the European Journal of Geography in 2023. Their expertise and dedication have been invaluable in maintaining the quality of our publications. In addition, the journal features 18 distinguished editorial board members from 12 countries, including renowned experts (60% men, 40% women) from various geographical research fields (This year we welcome 10 esteemed new members to our Editorial Board). In particular, we would like to express our sincere thanks to the following editorial board members for their help and support: 1. Alvanides Seraphim, Northumbria University, UK 2. ‪Bednarz W. Sarah, Texas A&M University, USA‬‬ 3. Capello Roberta, Politecnico di Milano, Italy 4. Cretan Remus, West University of Timisoara, Romania 5. De Miguel Gonzalez Rafael, University of Zaragoza, Spain 6. Eeva-Kaisa Prokkola, University of Oulu, Finland 7. Jerry T. Mitchell, University of South Carolina, USA 8. Kavroudakis Dimitris, University of the Aegean, Greece 9. Kiss Éva, CSFK Geographical Institute, Hungary 10. Knecht Petr, Masaryk University, Czech Republic 11. Kounadi Ourania, University of Vienna, Austria 12. Kolvoord Bob, James Madison University, USA 13. Leininger-Frezal Caroline, Université de Paris, France 14. Margaritis Efstathios, University of Southampton, UK 15. Specht Doug, University of Westminster, UK 16. Strobl Josef, University of Salzburg, Austria 17. Theobald Rebecca, University of Colorado Colorado Springs, USA 18. Yilmaz Ari, Bandirma Onyedi Eylul University, Turkey In 2023, we received a total of 116 submissions. Of these, 24 outstanding papers were published online (acceptance rate 21% - 2023), while 92, although commendable, did not make it to publication. Remarkably, these submissions included the contributions of 63 authors from 20 countries. The average review speed of the articles is about 7-9 weeks for the first round and about 4-6 weeks for the second round. The reviewers came from 31 countries, which shows a global co-operation: UK, USA, Austria, Belgium, France, Germany, Greece, Norway, Poland, Portugal, Ireland, Spain, Netherlands, Japan, Hungary, Iceland, Croatia, Czech Republic, Finland, Slovakia, Slovenia, Turkey, Romania and others. Thank you for your continued support and your contributions to this journal. Look forward to an exciting journey of discovery and innova-tion in the pages of the European Journal of Geography. Join us as we continue to shape the ever-evolving canvas of geographical exploration and knowledge. List of Reviewers 2023: 1. Alessandro Del Ponte, University of Alabama, USA 2. Ali Enes Dingil, Czech Technical University in Prague, Czech Repuplic 3. Alvanides Seraphim, Northumbria University, UK 4. András J. Molnár, Christian-Albrecht University of Kiel, Germany 5. Anja du Plessis, University of South Africa, Johannesburg, South Africa 6. Anqi Huang, Nanjing University of Information Science and Technology, China 7. Apostolia Galani, National and Kapodistrian University of Athens, Greece 8. Ari Yilmaz, Bandirma Onyedi Eylül Üniversitesi, Turkey 9. Audur Palsdottir , University of Iceland, Iceland 10. Barbara Szejgiec-Kolenda, Polish Academy of Sciences, Poland 11. Beth Schlemper, The University of Toledo, USA 12. Blaž Repe, University of Ljubljana, Slovenia 13. Bob Kolvoord, James Madison University, USA 14. Carina Peter, Philipps-University Marburg, Germany 15. Carlos Lopez Escolano, University of Zaragoza, Spain 16. Caroline Leininger, Université de Paris, France 17. Charalampos Tsavdaroglou, University of Amsterdam, The Netherlands 18. Christian Weismayer, Modul University Vienna GmbH, Austria 19. Darra Athanasia, National Technical University of Athens, Greece 20. Denise Blanchard, Texas State University, USA 21. Dimitris Kavroudakis, University of the Aegea, Greece 22. Don MacKeen, City of Glasgow College, UK 23. Doug Specht, University of Westminster, UK 24. Dragan Burić, University of Montenegro, Montenegro 25. Eeva-Kaisa Prokkola , University of Oulu, Finland 26. Efstathios Margaritis, University of Southampton, UK 27. Emmanuel Eze, University of Nigeria, Nigeria 28. Eva Psatha, University of Thessaly, Greece 29. Evangelos Rasvanis, University of Thessaly, Greece 30. Femke van Esch, Utrecht University, The Netherlands 31. František Petrovič, Constantine the Philosopher University, Slovakia 32. George Revill, The Open University, UK 33. Géza Tóth, University of Miskolc, Hungary 34. Grayson R. Morgan, University of South Carolina, USA 35. Hristina Prodanova, National Institute of Geophysics, Geodesy and Geography - Bulgarian Academy of Sciences, Bulgaria 36. Huda Jamal Jumaah, Northern Technical University, Iraq 37. İlkay Südas, Ege University, Turkey 38. Ilse van liempt, Utrecht University, The Netherlands 39. Isabel María Gómez-Trigueros, University of Alicante, Spain 40. Italo Sousa de Sena, University College Dublin, Ireland 41. Iva Miranda Pires, NOVA University Lisbon, Portugal 42. Iwona Anna Jażdżewska, University of Lodz, Poland 43. Jaime Diaz Pacheco, Universidad de La Laguna, Spain 44. Jan Christoph Schubert, Friedrich-Alexander-University Erlangen-Nuremberg, Germany 45. Jens Dangschat , TU Wien, Austria 46. Jernej Zupančič, University of Ljubljana, Slovenia 47. Jerry T. Mitchell, University of South Carolina, USA 48. Joan Rossello, Universitat de les Illes Balears, Spain 49. Joseph J. Kerski, ESRI, USA 50. Karina Standal, CICERO Center for International Climate Research, Oslo, Norway 51. Karl Donert, EUROGEO, Belgium 52. Koshiro Suzuki , University of Toyama, Japan 53. Kristine Juul, University of Roskilde , Denmark 54. Lauren Hammond, University College London, UK 55. Mahmood Shoorcheh, University of Isfahan, Iran 56. Maria Angeles Rodriguez-Domenech, Universidad Castilla La Mancha, Spain 57. María Lois , Universidad Complutense de Madrid, Spain 58. María-Luisa de Lázaro-Torres , Universidad Nacional de Educación a Distancia, Spain 59. Marko Krevs, University of Ljubljana, Slovenia 60. Marta Gallardo, Universidad Nacional de Educación a Distancia, Spain 61. Md Galal Uddin, University of Galway, Ireland 62. Md. Kausar Alam, Brac University, Bangladesh 63. Michaela Spurná, Masaryk University, Czech Repuplic 64. Miha Pavšek, Research Centre of the Slovenian Academy of Sciences and Arts, Slovenia 65. Muhammad Haroon Stanikzai , Kandahar University, Afghanistan 66. Neli Heidari, University of Hamburg, Germany 67. Nicholas Wise, Arizona State University, USA 68. Nikola Šimunić, Institute of Social Sciences Ivo Pilar, Croatia 69. Nikolaos Karachalis , University of the Aegean, Greece 70. Nuno Morgado, Corvinus University of Budapest, Hungary 71. Pablo Fraile-Jurado, Universidad de Sevilla, Spain 72. Panagiotis G. Tzouras, National Technical University of Athens, Greece 73. Peter T. Dunn, University of Washington, USA 74. Petr Knecht, Masaryk University, Czech Repuplic 75. Polyxeni Kechagia, University of Thessaly, Greece 76. Qi Zhou, China University of Geosciences, China 77. Rafael de Miguel González, University of Zaragoza, Spain 78. Rebecca Theobald, University of Colorado, USA 79. Remus Cretan, West University of Timisoara, Romania 80. Roberto Falanga, University of Lisbon, Institute of Social Sciences, Portugal 81. Saheed Adekunle Raji, University of Lagos, Nigeria 82. Sandra Sprenger, University of Hamburg, Germany 83. Sarah Bednarz, Texas A&M University, USA 84. Sebastien Bourdin, EM Normandie Bussiness School, France 85. Serafin Pazos-Vidal , European Association for Innovation in Local Development, Belgium 86. Susannah Cramer-Greenbaum, University of Warwick, UK, UK 87. Teemu Makkonen, University of Eastern Finland, Finland 88. Teresa Sadoń-Osowiecka, University of Gdansk, Poland 89. Theano S. Terkenli , University of the Aegean, Greece 90. Theodore Metaxas , University of Thessaly, Greece 91. Uwe Krause, Fontys School of the Arts, The Netherlands 92. Valériane Mistiaen , Université libre de Bruxelles, Belgium 93. Vesna Skrbinjek, International School for Social and Business Studies, Slovenia 94. Vincent Nzabarinda, Institute of Ecology and Geography, Chinese Academy of Sciences, China 95. Zsolt Tibor Kosztyán, University of Pannonia, Hungary

Investigation of Buddhist and Bon votive statues at the Very low power reactor VR-1

The nuclear analytical techniques are excellent tools for the investigation in various research disciplines, i.e. cultural heritage preservation, archaeology or anthropology. Most of these radioanalytical techniques require sufficient sources of radiation. So far, neutron imaging has mostly been used at high-power neutron sources, i.e. high-power research reactors. On the other hand, small nuclear research reactors can provide more options for investigations in multidisciplinary research. Since the development of the NIFFLER neutron imaging facility in 2020, neutron imaging has been one of the nuclear analytical methods used at the very low-power research reactor VR-1 of the Czech Technical University in Prague. This paper deals with the investigation of the internal structures of Buddhist and Bon votive statues from Central Asia at the Training reactor VR-1. The experimental investigation was conducted to explore the possibilities of using neutron imaging for cultural heritage research at very low-power research reactors such as the VR-1 reactor. The results of these unique experiments clearly showed the potential of the VR-1 reactor or possibly other very low-power research reactors in neutron imaging for multidisciplinary research, which can provide important data for anthropologists, archaeologists or experts in cultural heritage preservation.

Preface

This volume contains contributions to the XII. International Symposium on Quantum Theory and Symmetries (QTS12) was at Czech Technical University in Prague, Czech Republic, from Monday July 24 until Friday July 28, 2023.The Symposium series “Quantum Theory and Symmetries” (QTS) is a biannual meeting intended for physicists and mathematicians who are either applying symmetries to some physical model, or are studying mathematical objects that are relevant for physical applications.The first Symposium of this series was held in Goslar (Germany) in 1999, QTS-1, then it was held in Cracow (2001) QTS-2, Cincinnati (2003) QTS-3, Varna (2005) QTS-4, Valladolid (2007) QTS-5, Lexington (2009) QTS-6, Prague (2011) QTS-7, Mexico-city (2013) QTS-8, Yerevan (2015) QTS-9, Varna (2017) QTS-10, Montreal (2019) QTS-11.The Symposium QTS-12 was first planned to be in Moscow at the Moscow Institute of Physics and Technology in 2021, but was postponed by one year due to Covid-19, then it was postponed to 2023, July 24-28, and was held in Prague at the Czech Technical University (Department of Mathematics, Faculty of Nuclear Sciences and Physical Engineering, CTU in Prague) QTS-12.The Symposium QTS-13 is planned for the 2nd half of July 2025 to be held in Yerevan, Armenia.The volume is organised as follows: it starts with notes in memory of H. D. Doebner. Then the invited talks at the plenary sessions and the public lecture are published followed by contributions in the parallel and poster sessions in alphabetical order.List of Editors, Advisory committee are available in this Pdf.

Resonance cavity as an education tool in PlasmaLab@CTU

PlasmaLab@CTU is a laboratory at the Czech Technical University in Prague dedicated to train new fusion physicists and engineers in plasma physics and technology with focus on the plasma diagnostics. The resonance cavity is one of the devices which train students in handling microwaves together with vacuum and plasma physics. The contribution will present the design of the resonance cavity, and measurements of the density as the function of the pressure in different gases. It will also present this experiment as an educational tool for the fusion community.The resonance cavity is a metal cylinder placed inside a glass container. It can be evacuated via holes in the top lid. Plasma is generated between an electrode inserted inside and the cylinder itself by RF source with the frequency of 13.5 MHz, and the power of roughly 70 W. Two antennas are placed inside the resonator in the bottom lid to launch and measure the resonant modes in the cavity. Plasma density can be estimated from the shift of the resonance peaks with/without plasma.The experiment can operate with five gases. It can be remotely controlled via its own interface through the internet. The remote control is an important feature of the PlasmaLab@CTU. It aims in continuing in the tradition of educational events already established by the GOLEM tokamak.

The measurement of the influence of the adhesion loss on the dynamic load of the drive reaction rod on the roller rig

The dynamic behaviour and dynamic phenomena in traction drives of railway vehicle has been studied for decades. Generally, in these days the motivation for this research is to look for answers related with service problems, which has been risen, e.g. an overloading of mechanical components as wheelsets or an intention to improve control systems of traction drives of railway vehicles. This problematic has also motivated the research at the Faculty of Mechanical Engineering at the Czech Technical University (CTU) in Prague. Nowadays it is also usual, that the main research tool has been a simulation based on a mathematical model of a railway vehicle or its specific components, as testing on real vehicles is very demanding regarding costs. However, there is an alternative – a roller rig. At the CTU in Prague there has been modernized the second roller rig for purposes of measurement regarding the torsion dynamics research, to support PhD students for their theses and possibly to extend the education for students oriented on the railway vehicle’s design. This contribution brings results of measurements just from the problematics of torsion oscillations and dynamics. Specifically, further presented measurements are on the loss of the adhesion in the contact of the wheelset and rollers, as the substitution for the railway, its impact on the reaction rod overloading and study of the axle load influence on the transition phenomena.

Application of the Source-Jerk method using a neutron generator in a subcritical reactor

This paper describes the application of the Source-Jerk method using a neutron generator in the VR-1 reactor. The experiments were carried out on a shutdown reactor with subcriticality greater than -10 βeff. A D-D neutron generator located in the radial channel of the VR-1 reactor was used as an external neutron source for the Source-Jerk method. The obtained results were discussed and compared with a conventional Source-Jerk method used at the VR-1 reactor and with the values calculated by the Serpent 2 code. The presented experimental works and their results will allow to extend the methods of reactivity measurements on the VR-1 reactor. They will also help to optimise reactivity measurements on the new subcritical reactor VR-2, which is currently being commissioned at the Czech Technical University in Prague.

Reconstruction with a double-constrained implant design after complex shoulder extra-articular resection

BackgroundApproximately, one-third of patients with tumors of proximal humerus will require an extra-articular resection to achieve oncologic margins. This procedure yields poor functional outcomes with a considerable rate of revisions. Unconstrained implants are prone to instability hindering also function of the elbow and hand, whereas constrained shoulder reconstructions suffer from early aseptic loosening of the glenoid component due to bone overload. The purpose of this study was to develop a constrained implant suitable for extra-articular resection with loss of function in deltoid and rotator cuff, which would provide both stability and passive motion, whilst also decreasing the risk of aseptic loosening of the glenoid component.MethodsIn cooperation with Czech Technical University in Prague, we devised an implant consisting of two constrained joints in series connected by a dumbbell piece. The biomechanical analysis showed a reduction of load transfer to the glenoid component with a torque of 8.6 Nm capable of generating an 865-N pulling force on bone screw to just 0.07 Nm, hence shielding the glenoid component from undesired forces and decreasing the risk of aseptic loosening. Three patients with extra-articular resection with a total loss of function of both rotator cuff and deltoid muscle received this type of reconstruction. The average follow-up was 16 months.ResultsThe surgical technique is straightforward. The surgery took 175 min on average with average blood loss of 516 ml. There were no surgical- or implant-related complications. All three patients were pain-free and had a stable shoulder joint after the reconstruction. All had fully functional elbow, wrist, and hand joints. The average Musculoskeletal Tumor Society (MSTS) score was 21/30 (70%). All patients were pleased with the results.ConclusionThe presented innovative implant design has demonstrated to be a promising alternative for reconstruction in these challenging cases.

Models to Analyze Risk in Time and Cost Estimation of Tunneling Projects

Time and cost estimation of tunneling projects is usually performed in a deterministic manner. However, because the deterministic approach is not capable of dealing with uncertainty, probabilistic methods have been developed over the years to better account for this problem. Three models of this type are the Decision Aids for Tunneling (DAT) and two models developed at KTH Royal Institute of Technology and the Czech Technical University in Prague. To conduct a probabilistic time and cost estimation, it is important to understand and account for not only the uncertain factors that affect the project time and cost but also the involved parties’ different interests and contractual responsibilities. This paper develops a risk model for the specific purpose of time and cost estimation of tunneling projects. In light of this model, the practical application of the three probabilistic models is discussed from a risk-aware decision-maker’s perspective. The acquired insights can be helpful in increasing the experts’ risk-awareness in modeling time and cost of tunneling projects.

Online training and education from the VR-1 reactor—Lessons learned

Hands-on education and training is a key part of fixing and developing technology knowledge and is an inherent part of many engineering and scientific curricula. However, access to large complex training facilities, such as nuclear reactor, could be limited by various factors, such as unavailability of those facilities in the region, high traveling costs or harmonization of the schedules of hands-on E&T with theoretical lectures and with the operational schedule of the facility. To handle the issue, several success stories have been reached with the introduction of the Internet Reactor Labs (IRL). The Internet Reactor Labs can strongly contribute to accessibility of training at research reactors and can contribute to improvements in their utilization. The paper describes the development of the Internet Reactor Lab at the VR-1 reactor of the Czech Technical University in Prague. Contrary to single-purpose IRLs, it presents various modalities of online teaching and training in experimental reactor physics and reactor operation in general as well as outreach activities that have been developed in recent years.

Investigation of concentric-zonal color effects in polyphase ceramic samples by x-ray fluorescence analysis.

The purpose of this study is to investigate and analyze new concentric-zonal color effects in polyphase ceramic samples, particularly in a ceramic sample obtained from coal ash in the Ekibastuz coal basin. The study aims to explore the nature and characteristics of these color bands through x-ray fluorescence analysis, and provide a qualitative and quantitative analysis of the obtained x-ray fluorescence spectra. This paper presents the results of the study of new volume-surface concentric-zonal color effects in polyphase ceramic samples. Concentric-zonal color bands on the cross-sectional surface of a ceramic cylindrical sample were investigated by using x-ray fluorescence analysis. The experimental work was carried out at the laboratory of the Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague. A comparative qualitative and quantitative analysis of the obtained x-ray fluorescence spectra was carried out.

CHISA 2022 – 26th Worldwide Meeting of Chemical Engineers

You have just started reading a Special Issue of Chemical Engineering & Technology which consists of contributions (both oral and poster) presented at 26th International Congress of Chemical and Process Engineering – CHISA 2022. It was the first Prague's face-to-face meeting of chemical engineers after restrictions connected with Covid-19 pandemic and it was organized with great enthusiasm because everyone was looking forward to personal interactions. It was held during August 21–25 in Prague at the Faculty of Civil Engineering, Czech Technical University in Prague. Chemical Engineering is a multidisciplinary scientific field that covers topics like reaction engineering and catalysis, computer process design, separation processes, and multiphase reactor systems. The format of the CHISA Congress has been changed from its previous versions. The main topics covered a wide range of disciplines starting at Ethics in Chemical Engineering through Global Thoughts, Matter in Motion to Green Issues and Energy and this change in format has lead towards more intense interaction between chemical engineers of all professional levels – students, academics, scientists, and industrial experts. The participants were invited to attend many interesting contributions dealing with the influence of chemical industry on the environment and reducing its impacts, mathematical modeling of the most important industrial processes and development towards their improvement, new processes leading to production of green energy, synthesis of new materials and catalysts together with economic evaluation of processes and many more. Due to the multidisciplinary scope of the conference, each participant was able to attend a substantial number of contributions of his own interest. The conference is very well known for its high scientific quality and this year was not different. The CHISA congress is also famous for its rich social program and is considered a place “where science meets culture”. The cultural program covers, e.g., a night with classic music, a student beer party, and a congress dinner. This ultimate mix of heterogeneous activities contributes to a better interconnection between students, academics, and industrial experts which always leads towards more intense cooperation. I would like to express my deepest appreciation to all participants of the conference and also to those who were willing to contribute a paper to this Special Issue. I would also like to apologize to others who could not make it to its final publication. The level of the contributions was of high quality and the role of a Guest Editor is always very difficult. I would also like to thank Dr. Barbara Boeck, Editor in Chief of Chemical Engineering & Technology, for giving me the opportunity to be the Guest Editor for the first time. I hope you enjoy reading this issue and I am looking forward to seeing you at the next CHISA congress in 2024. Dr. Pavel Krystyník Faculty of Environment, Jan Evangelista Purkyne University in Usti nad Labem Institute of Hydrodynamics of the Czech Academy of Sciences Pavel Krystyník

A smeared crack formulation for simulating fracture of fibre-reinforced concrete by means of a trilinear softening diagram

This study presents a smeared crack model for reproducing the fracture behaviour of FRC that is based on an embedded crack formulation used lately with this material. In both cases, a trilinear softening diagram allows reproducing the post-peak behaviour correctly. The model proposed here differs from the one on which it is inspired, since it is a smeared crack model based on the crack band concept where the material damage is isotropic and controlled by a damage factor ranging from 0 to 1, while the original model is an embedded crack model that allows fracture in three directions per element. This new formulation overcomes some limitations of the embedded crack model, that could only be used with triangular elements with an only integration point, since it can be used with triangular and quadrilateral elements with any number of integration points. Unlike previous models, developed for commercial codes, this model is developed in OOFEM, a free finite element code developed at the Czech Technical University in Prague (Czech Republic) and Chalmers University of Technology (Sweden), thus providing the general public with an advanced tool that allows reproducing fracture in structural elements made with fibre-reinforced concrete elements. This work shows that the proposed formulation provides similar results to those obtained with the model on which it is inspired under different situations: mode I fracture, size effect analysis and, finally, modes I and II mixed fracture.

IARD 2022 The 13th Biennial Conference on Classical and Quantum Relativistic Dynamics of Particles and Fields

Preface The International Association for Relativistic Dynamics was organized in February 1998 in Houston, Texas, with John R. Fanchi as president. Although the subject of relativistic dynamics has been explored, from both classical and quantum mechanical points of view, since the work of Einstein and Dirac, its most striking development has been in the framework of quantum field theory. The very accurate calculations of spectral and scattering properties, for example, of the anomalous magnetic moment of the electron and the Lamb shift in quantum electrodynamics, and many qualitative features of the strong and electroweak interactions, demonstrate the very great power of description achieved in this framework. Yet, many fundamental questions remain to be clarified, such as the structure of classical relativistic dynamical theories on the level of Hamilton and Lagrange in Minkowski space as well as on the curved manifolds of general relativity. There, moreover, remain the important questions of the covariant classical description of systems at high energy for which particle production effects are not large, such as discussed in Synge’s book, The Relativistic Gas, and in Balescu’s book on relativistic statistical mechanics, and the development of a consistent single and many body relativistic quantum theory. In recent years, highly accurate telescopes and advanced facilities for computation have brought a high level of interest in cosmological problems, such as the structure of galaxies (dark matter) and the apparently anomalous expansion of the universe (dark energy). Some of the papers reported here deal with these problems, as well as other fundamental related issues.It was for this purpose, to bring together researchers from a wide variety of fields, such as particle physics, astrophysics, cosmology, foundations of relativity theory, and mathematical physics, with a common interest in relativistic dynamics, to investigate fundamental questions of this type, that this Association was founded. The second meeting took place in 2000 at Bar Ilan University in Israel, the third, in 2002, at Howard University in Washington, D.C., and the fourth, in 2004, in Saas Fee, Switzerland. Subsequent meeting took place in 2006 at the University of Connecticut Storrs, in 2008 at Aristotle University of Thessalonica, in 2010 at National Dong Hwa University, Hualien, Taiwan, in 2012 at the Galileo Galilei Institute for Theoretical Physics (GGI) in Florence, in 2014 as the University of Connecticut Storrs, Connecticut, in 2016 at Jožef Stefan Institute in Ljubljana, Slovenia, and in 2018 in Mérida, Yucatán, Mexico, under the sponsorship of the Instituto Politécnic Nacional. The 2020 meeting, planned for Czech Technical University in Prague, was successfully held online at the height of the Covid-19 pandemic, and the physical meeting in Prague was delayed to 2022.The 2022 meeting forms the basis for the Proceedings that are recorded in this issue of the Journal of Physics: Conference Series. Along with the work of some of the founding and newer but already much engaged members of the Association, we were fortunate to have lecturers from application areas that provided strong challenges for further developments in quantum field theory, cosmological problems, and in the dynamics of systems subject to accelerations and the effects of general relativity. Topics treated in this issue include studies in general relativity and astrophysics, relativistic dynamics and electrodynamics, quantum theory and particles, and foundations of relativistic dynamics.This first physical meeting of the Covid-19 era took place 6 - 9 June at Czech Technical University in Prague, as originally planned for 2020. The meeting was divided into seven plenary sessions over four days. As a result of continued travel restrictions in some areas, a small number of talks were delivered by videoconferencing. The papers presented in this volume represent extensions and refinements to the conference talks, building on feedback and discussions associated with the lectures. We once again express our gratitude to Czech Technical University, and especially the local conference chair Petr Jizba, for their generous hospitality.List of Scientific Advisory Committee, International Organizing Committee and Editorial Board of the proceedings, Dedication are available in this Pdf.

Editorial to the Special Theme Sustainability

Sustainability represents a commonly agreed global development goal. It aims at ensuring the quality of life on Earth for current and future generations. Sustainability should thus become the fundamental overarching concept for the efficient/high-quality design and operation of any product or service throughout its lifecycle—focusing on all three pillars of sustainability—social, environmental, and economic. Among the different socioeconomic sectors, dealing with the impacts that the construction sector has is fundamental, as it strongly contributes to many of the pressing issues that need to be addressed. Not only do we need to improve the economic, environmental, and social performance of our built environment, but we also need to be better prepared for new conditions that are appearing as a cause of global challenges (e.g., climate change). The importance of this approach is all the more clear in light of an increasing number of man-made and natural disasters occurring globally. Thus, current developments and changes in the environment and socioeconomic situation require improvements in the technology of different processes that are involved in construction projects. In this context, concrete is a particularly interesting material, because it has a great potential for new technical solutions meeting new requirements, leading to the necessary reduction of environmental impacts and at the same time improvement of social and economic conditions, including safety and reliability during emergency situations. However, considering the huge volume of global concrete production and the negative impacts closely linked to its production, the overall environmental negative impact associated with the construction of concrete structures on a global scale is considerable. In view of the above global situation, it is of utmost importance to focus on the introduction of new production and construction technologies, advanced design techniques and efficient operation, maintenance, and recycling techniques of concrete structures. Concrete mixes, concrete products, and concrete structures should be designed to meet the requirements of sustainability—namely, to minimize their negative impacts and increase the positive impact on society, the environment, and the economy. This could be achieved by increasing the quality and durability of concrete structures throughout their life cycle, through (i) improvements in design methods, (ii) development of concrete mixtures, composite materials, and reinforcement methods, (iii) modernization of concrete technology, (iv) development of integrated design approaches, and (v) innovation in maintenance, repair, demolition, and recycling processes. This requires the involvement of all actors in the construction process, from material manufacturers, designers, and builders to users, and their conviction and initiative in the need to achieve better results in terms of sustainability requirements. This special theme of Structural Concrete journal: Sustainability of Concrete Structures collects a selection of contributions related to different aspects of sustainability showing potential of concrete structures to contribute to the achievement of the Sustainable Development Goals (SDGs) set by the United Nations in 2015 as an action plan until 2030. The content of this special theme volume covers issues related to Life Cycle Assessment of concrete structures, carbon neutrality, use of recycled concrete and other recycled components, optimization of concrete structures, and many other issues bringing the contribution of concrete research and development to SDGs. We trust that the presented selection of articles is of interest to the concrete community focusing on the development of concrete structures toward a sustainable and resilient built environment as a contribution for future generations. Petr HajekDepartment of Architectural Engineering,Faculty of Civil Engineering, Czech Technical University in Prague, Czech Republic; Member of fib COM7, Convener of fib TG7.1: Sustainable Concrete—general framework; Member of fib COM10, TG10.1: Model Code 2020; Member of TG6.3:Sustainability of structures with precast elements and TG1.5:Structural sustainability. Albert de la Fuente AntequeraAssociate Professor, Civil and Environmental Engineering Department, Universitat Politècnica de Catalunya, Barcelona, Spain. Nikola TošićUniversitat Politècnica de Catalunya—BarcelonaTECH (UPC), Barcelona, Spain. Irene JosaDepartment of Civil, Environmental and Geomatic Engineering, University College London (UCL), London, UK. Petr Hajek, Department of Architectural Engineering, Faculty of Civil Engineering, Czech Technical University in Prague, Czech Republic; Member of fib COM7, Convener of fib TG7.1: Sustainable Concrete—general framework; Member of fib COM10, TG10.1: Model Code 2020; Member of TG6.3: Sustainability of structures with precast elements and TG1.5: Structural sustainability. Albert de la Fuente Antequera, Associate Professor, Civil and Environmental Engineering Department, Universitat Politècnica de Catalunya, Jordi Girona 1-3, 08034 Barcelona, Spain. Nikola Tošić, Universitat Politècnica de Catalunya—BarcelonaTECH (UPC), Jordi Girona 1–3, 08034 Barcelona, Spain. Irene Josa, Department of Civil, Environmental and Geomatic Engineering, University College London (UCL), London, UK.

Plasma diagnostics using fast cameras at the GOLEM tokamak

Tomographic inversion of radiation determines spatial distribution of tokamak plasma radiation sources using line integrated plasma projections data. For measurements of the projections, fast visible radiation matrix cameras became broadly applied on tokamaks in recent past. These novel cameras opened new possibilities in high temperature plasma studies.The GOLEM tokamak of the Czech Technical University in Prague strives to implement up-to-date diagnostics with enhanced temporal and spatial resolution. Therefore, a novel diagnostic system of two crossed monochrome cameras Photron FASTCAM MINI UX50 was integrated into the GOLEM diagnostics. The proposed contribution will detail their novel port mounts (vertical and horizontal) at the GOLEM tokamak which have been designed so that additional optical measurements of the plasma core (e.g. plasma spectroscopy) is possible.As the main purpose of this study, we shall focus in particular on the frame rate potential which is high enough to make detection and observation of highly transient phenomena in the GOLEM plasmas possible. Progress in solving specific challenges of the ill-conditioned tomographic inversion via the algorithm optimization and testing for the GOLEM tokamak will be presented together with the first tomographic results.

Principles and Applications of Accelerator Mass Spectrometry

Accelerator mass spectrometry (AMS) represents an ultrasensitive analytical method for measurement of long-lived radionuclides, namely 14C, 10Be, 26Al, 41Ca, 129I, and 236U. It provides information about isotopic ratios up to 10–16 in samples of mass from several miligrams to tens of micrograms. The first AMS laboratory in the Czech Republic was built in Nuclear Physics Institute, Řež, in collaboration with Archaeological Institute, Prague (both Czech Academy of Sciences) and Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, and equipped with AMS MIELA (Ionplus AG, Switzerland). This review summarizes history, principles, and use of this unique analytical method.

New Neutron Imaging Facility NIFFLER at Very Low Power Reactor VR-1.

The paper describes the construction of the neutron imaging facility at the very low-power research reactor VR-1. The training reactor VR-1 is operated by the Czech Technical University in Prague, Czech Republic. It is mainly used for the education of students in the field of nuclear engineering as well as for the training of professionals. Neutron imaging is the new field of VR-1 reactor utilisation currently under development. Extremely low reactor power at the level of 100 W brought many challenges that were necessary to overcome to build and commission a sustainable neutron radiography facility. The paper describes the reactor's neutron flux verification and the basic concept and design of the neutron imaging instrumentation. The first experimental results were mainly dedicated to testing the detection system for different radial beam port configurations, different L/D ratios, and different exposure times. Preliminary results of neutron radiography and tomography measurements at VR-1 clearly showed the potential of using neutron imaging in low-power reactors such as the VR-1 reactor.

Holistic analysis of indoor environmental quality in refurbished school using HAIEQ methodology - Czech case study

The subject of this paper is a detailed analysis and evaluation - audit of the quality of the indoor environment in the reference zone of a primary school building in the Czech Republic. The analysis and subsequent evaluation is performed by the certified CTU HAIEQ (Holistic Assesment of Indoor Environmental Quality) methodology, developed at the Department of Building and Construction Engineering of the Czech Technical University in Prague. The analysis is based on a detailed survey of the building, measured data of physical variables of the indoor environment and subjective assessment from the user's point of view. The evaluation of the quality of the environment is carried out in 8 categories - LS Location and location of the building in terms of external environment and social connections; STI Structural-technical design and interior of the evaluated zone; TCW Thermal comfort in cold season; TCS Thermal comfort in warm season; IAQ Air quality; LC Light environment; AC Acoustic environment and EC Electro-magnetic, -ionic -static fields. Each category has 5-8 criteria to be evaluated. The outcome of the indoor environment audit using the HAIEQ methodology is the identification of critical areas and the proposal of possible measures to improve the current situation. The implementation of the proposed measures must be carried out in accordance with applicable regulations and laws by authorized persons. The method used does not guarantee that all problem areas will be found using it and the preparer is not responsible for problems not found during the analysis of the building. The results of the measurement and evaluation methodology are not a substitute for an assessment by a sanitary service.

How the COVID-19 changed the hands-on laboratory classes of electrical measurement

This article depicts how COVID-19 affected practical teaching at Czech Technical University in Prague, Faculty of Electrical Engineering, Department of Measurement. It introduces the subject of Electrical Measurement and its hands-on laboratory classes. The course applies to more than 100 undergraduate students per semester. Since COVID-19 mainly affected the teaching of the hands-on laboratory courses, the article narrates how the COVID-19 lockdown has changed classes. An experience with the rapid transformation of lectures during the lockdown focusing on the hands-on laboratory classes is discussed, and the improvements that have been done to preserve its objectives, but also to adapt them to another possible lockdown, and the need to switch to the distance teaching, is revealed. The changes have been inspired by the results of a survey carried out among more than 250 students. The outline of the laboratory tasks transformation with an emphasis on the possibility of switching the real face-to-face measurement to the distance teaching remote lectures is described. The change includes reducing the number of laboratory tasks taught while preserving most of the objectives. All 11 new laboratory tasks are described in detail, and it is discussed how the possible change from hands-on to remote classes will affect every task.