bluuebunny/crossref_metadata_2025_split huggingface dataset:
Visualization of laser back-reflection distribution during laser welding
Authors: Horník Petr , Šebestová Hana , Novotný Jan , Mrňa Libor 
Published: December 2021

Abstract
There are several approaches to weld quality monitoring during laser welding. Reflected laser radiation carries partial information about the welding process. Fibre lasers has usually a built-in diode to detect excessive back-reflected laser radiation to protect the laser source from damage. Reflected laser radiation measured in the laser source is compared with reflected laser radiation measured in the welding head. Moreover, coaxial high-speed imaging with a narrow bandpass filter on laser wavelength is used to visualize the reflected laser radiation. The advantage of this solution is that no additional illumination is needed and the reflected laser intensity and spatial distribution can be obtained from the image. Keyhole inlet dimensions are measured and related to the laser power. The transition between laser welding modes is studied.
A study on use of wobble features in laser welding of low alloy steel joint with butt joint configuration
Authors: Kankala Timo , Salminen Antti 
Published: December 2021

Abstract
Laser welding is modern digital welding process, which thanks to several advantages over traditional welding processes, is gaining ever growing role in manufacturing. The process has still some weaknesses. The better the beam quality the smaller the focal point, the actual welding tool, diameter is. Typically, because of this the welding of joints with lesser quality e.g. larger air gap is difficult or even impossible. So-called beam manipulation opens opportunities to deal with the problem. The dynamic beam manipulation gives opportunities to control the weld dimensions during the welding process by the requirements of individual locations of weld joint. This study used the two dimensional scanner to manipulate beam during welding with so called wobble function. Four different wobble configurations were tested in welding of low-alloyed steel with different joint qualities. The wobble typically made the welds wider, provided typically higher heat input and thus lowered the hardness of the joint. Wobble increased typically the root quality, but there are differences between different wobble parameters. It was possible to weld joints with wider air gaps in the selected material thickness, but the wider air gap and wobble caused finally, when wide enough the sagging of the joint.
Ultrashort-pulsed laser processing with spatial and temporal beam shaping using a spatial light modulator and burst modes
Authors: Lutz Christian , Esen Cemal , Hellmann Ralf 
Published: December 2021

Abstract
We report on the effect of simultaneous spatial and temporal beam shaping on the ablation rate, ablation efficiency and the resulting surface characteristics of micromachined stainless steel using ultrashort-pulsed lasers. Beam shaping and the use of pulse bursts are promising methods to allocate the over the last decades increasing laser power of ultrashort-pulsed lasers in ablation processes. While the individual effects of beam shaping and pulse bursts on the ablation characteristics have recently been examined, the combination of both has not yet been adequately investigated. Using a spatial light modulator to generate different spot distributions with up to six spots and different separations it is possible to spatially distribute the available laser power. In combination with temporal beam shaping using a 200 kHz repetition rate and pulse bursts with a 40 MHz intra-burst rate, we investigate the influences in a scanning-based process and find an increasing ablation rate and efficiency for higher fluences. Subsequently using bursts in combination with a multi-spot beam profile, we found a distinctive emergence of cone like protrusions and a smoothing effect for fluences between 1.5 J/cm² and 3 J/cm² with six spot beam profile.
Use of Construction Project Scheduling Methods in the Czech Republic
Authors: Jana Nováková , Martin Nový 
Published: December 2021

Abstract
This article deals with research in the field of construction project scheduling in the Czech Republic. The aim of the research was to determine the scheduling maturity within project management in selected medium-sized and large companies and the change in the use of these methods during the global COVID-19 virus pandemic. The research presented in this article consists of three consecutive steps: determining the research area and the research question, designing a research plan, conducting data collection and analysis and compiling research results. For the purposes of this research, the research question was defined as follows: How do the project management scheduling methods differ depending on the company size in the selected companies in the Czech Republic? For understanding both the context and the situation in the surveyed companies, qualitative approaches to data collection and analysis were used, particularly in-depth interviews and encoding method. This approach was chosen mainly due to the fact that in case of quantitative research, the results tend to be improved by the respondents or irrelevant respondents are questioned. The semi-structured interview questions which were created based on the findings of the current state of scientific knowledge and literary research were used for the needs of in-depth interviews. Open questions (topics) related to the respondents' experience, perceptions and opinions were created as a part of the preparation process. The aim was to get more reliable and relevant answers to the questions asked. The research, which lasted for 6 months, involved 10 medium-sized and large companies from the Czech Republic. The change in the use of scheduling methods took place mainly in medium-sized companies. Large companies emphasized scheduling even before the pandemic, medium-sized companies often neglected this area - planning was not documented, linked to other projects, suppliers or customers. The pandemic has changed this situation. Companies that participated in this research have started to understand integrated scheduling approaches and are going to invest or consider to invest in complex software solutions in the near future.
Friction Coefficient of Load-Bearing Elements of Building Technical Facilities
Authors: Hrabovský Leopold , Michalik Peter 
Published: December 2021

Abstract
The engineering activities in construction are a set of a wide range of activities that are performed, for example, for the purpose of the installation or mandatory replacement or modernisation of lifts. On the territory of the Czech Republic, there are standards that strictly prescribe what is required to repair and replace on an existing lift in order to ensure the greatest possible safety when riding the lift, but also the high reliability and dependability of the lift. Polyurethane lift belts were developed and used for the vertical movement of lifts at the turn of the millennium. Due to patent rights, they were reserved solely for selected manufacturers of lifts. The classic ropes with a circular cross-section are currently being replaced more and more frequently in construction engineering by flat ropes or belts due to their undisputed advantages. This paper describes the construction design and implemented equipment on which it is possible to determine, in the laboratory, the value of the rope friction coefficient in the given type of traction disc grooves. To be specific, this paper describes the friction coefficient determined in a laboratory, in dry and clean conditions, of a flat rope with a polyurethane sheath on the circumference of the traction disc. The friction coefficient values were acquired indirectly, i.e. by measuring the tractive forces in the approaching and receding rope branches on the rotating traction disc powered by an electric drive. The friction coefficient was determined from the measured values of both tractive forces during the course of a single experimental measuring through a calculation from Euler’s relation. The value of the receding force was obtained using two methods that differ from each other in the manner of attachment (by a screw or compression springs) of the end of the rope to the load-bearing construction of the measuring device. The information obtained from the experimental measurements made it possible to compare the measured values of the rope friction coefficients with the values given by the manufacturers and to make the conclusion that the method used to determine the friction coefficients and the set of laboratory activities and procedures for determining the friction coefficients on the testing equipment is suitable and usable in practice.
Letter Graphics in the Facade of a Building – Composition and Message
Authors: Lipowicz-Budzyńska Alina 
Published: December 2021

Abstract
The paper discusses art and communication in architecture. Façade graphics, alongside their compositional and aesthetical qualities, may also contain visual elements that are part of a message. One of the ways of sending such a message is by incorporation of letters. The article looks at preliminary research on the form and content of messages contained within façade graphics. The author analyses the objective of placing letter graphics on a façade, and how they relate to the information and message that are given. An important part of the analysis is the examination of the applied artistic means tied to the meaning, and how they relate to the building’s structure. This phenomenon was examined based on eight buildings constructed over the past two decades. In each of them, graphical techniques of digital and screen printing were used. The majority of them are located in Europe, and due to the global nature of artistic phenomena, there is no limited smaller area of research.
Strategies to Improve Urban Energy Efficiency for Urban Resilience
Authors: Gültekin Yalim 
Published: December 2021

Abstract
Greenhouse gas (GHG), which is a determining factor in climate change is a result of human activities, namely climate change is human-caused (anthropogenic). Cities, where 60% of the world's population of approximately 7.3 billion living today, are responsible for 60-80% consumption of energy, which is the lifeblood of intense human activities, thus at least 70% of GHG. Nevertheless, cities are the cause of climate change and other global environmental problems, as well as the innovation centres and laboratories to deal with their impact. With climate change becoming more explicit and active in the 21st century, researchers, governments and international institutions question cities’ strength/vulnerability against these problems, especially their energy production and consumption patterns that cause GHG, and they anticipate that urban resilience be the motivating force for urban policies. The widespread and effective use of renewable energy is regarded as an influential tool against climate change. However, this should be endorsed by spatial strategies. In the light of this approach, this study evaluates the urban form, building design and production technologies that are focused on energy efficiency and renewable energy use.
Real-Time Deformation Measurements Using Single Image Photogrammetry
Authors: Hideghéty Andrej 
Published: December 2021

Abstract
Most photogrammetric measurements are currently based on image acquisition in the field and subsequent processing in office environment with certain temporal delay. However, in some cases it is necessary to process the data real-time, or at least in-situ. Bridge load testing is an example of measurement processing directly at the place of imaging, where almost immediate information about the current state or change of the object is required. An algorithm is developed for these purposes, including a camera controlling software and a MATLAB code that identifies and quantifies the shifts of the observed points in the image plane. The observed points are in the shape of black disks on a white background. Using a horizontal camera position individual epochs are captured. Each image is immediately transferred to a computer via Wi-Fi. The MATLAB code then loads the image and binarizes it. Binarization of the image is performed by the Canny edge detector. Using normalized 2-D cross-correlation, the algorithm determines the approximate coordinates based on a target template. A function performs least squares ellipse fitting and determines the center of the target in sub-pixel accuracy, the semi-major axis, the semi-minor axis and the rotation angle of the ellipse. The target detection is executed in a while cycle loop, which compares the point coordinates from each epoch to the initial state, thus quantifying the deformations in pixels. If the next image is not yet available, the loop restarts. The deformations are calculated based on the known scale of each target. This paper presents a detailed description of the development of the algorithm, the results achieved and the proposed improvements going forward.
Comparison of the Performance Development of Construction Companies in the South Moravian Region of the Czech Republic: A Case Study
Authors: Vítková Eva , Kocourková Gabriela , Vaňková Lucie , Slováček Štěpán 
Published: December 2021

Abstract
Historically, construction has always been one of the key sectors for state economic production. It has undergone developments over the years closely related to the world economic situation. The Czech Statistical Office, which processes annual analyses of construction production and describes market development resulting from the analysis of the construction industry deals with the development of economic sectors in the Czech Republic. A set of financial indicators which provide information on the overall market situation is annually published as a part of the research of the Ministry of Industry and Trade of the Czech Republic in the form of a corporate sector financial analysis. The performance of construction companies can be measured by various indicators. The most important performance indicator is the return on sales. This financial analysis ratio is quarterly published as a statistic within the construction sector in the national statistics published by the Ministry of Industry and Trade. The aim of the research described in the article is to compare the performance development of construction companies operating in the South Moravian Region of the Czech Republic. 12 samples of construction companies (4 samples representing the category of small, medium-sized, and large companies) were chosen for comparison. Their return on sales was calculated on the basis of financial statements in the 2013 – 2019 period. This value was plotted in the development trend, which was subsequently compared with the national statistics. The overall comparison of the performance development of construction companies, which was quantified using macroeconomic indicators, was carried out in the South Moravian Region. The macroeconomic indicators of the South Moravian Region were also compared with the national indicators provided by the Czech Statistical Office.
Proposed Method of Distribution of Horizontal Loads on Stiffening Walls
Authors: Jasiński Radosław 
Published: December 2021

Abstract
Numerical methods are commonly used to determine internal forces in stiffening walls. Extreme internal forces can be easily generated not only in slab-and-wall structure, but also in the bar system. It is always time-consuming to build such a structure, thus it is not used in single- or multi-family buildings with a simple wall arrangement. Then, a simple analytical model can be used to calculate internal forces in walls. Eurocode 6 (prEN 1996-1-1:2017) does not contain specific guidelines to calculate internal forces in walls and to use numerical methods or other reliable methods. This paper presents the procedure for determining internal forces in a building with a simple wall arrangement. The proposed method is based on the division of a wall with openings into components. The results were compared with values of internal forces determined by the linear elastic FE shell model. Rotation centre (RC) of the wall plan was demonstrated to be a significant factor which, besides bending and shear stiffness, had an impact on load distribution.
Comparison of conventional and passive public utility buildings in Poland
Authors: Kołodziejczyk-Kęsoń Ada 
Published: December 2021

Abstract
Poland sees the increasing popularisation of sustainable housing and the growing awareness of the importance of sport development. A good physical condition of residents translates into effective work, whereas caring for the environment improves living standards. Introducing healthy lifestyle from an early age has the best results. Due to this fact in Poland every school has its own sports hall. The pilot programme to build swimming pools near every primary school was introduced in Lower-Silesian district and it is called ‘Dolnośląski Delfinek’ (Lower Silesian Little Dolphin). Swimming pool buildings are characterised by high demand for heat. Their operation burdens district budgets and indirectly every taxpayer. Those facilities are occasionally rented commercially to earn some money for maintenance expenses. The costs usually exceed the income of those buildings. The article discusses results of thermo-vision (infrared) tests and presents the analysis of the technical documentation of twenty eight public utility buildings located in Poland. The investigations encompass conventional, energy-saving and passive buildings. The conventional buildings described in the work are school swimming pools from the programme ‘Dolnośląski Delfinek’ (Lower-Silesian Little Dolphin), whereas energy-saving and passive buildings include office, industrial, hotel, educational and sports buildings (including an indoor swimming pool). This article aims to find the most effective design manner and energy-saving sports buildings construction such as swimming pools. The results obtained in the tests indicate the necessity of compliance with the energy-saving technology in the design and construction of public utility buildings. A conclusion arises that swimming pool buildings are the most suitable candidates for passive buildings.
Thermal Cracks Development Study in Newly Built Reinforced Concrete Residences
Authors: Hashmi Hymabaccus El Fez , Asish Seeboo 
Published: December 2021

Abstract
Concrete blocks and concrete assemblies are affected by natural physical conditions, which impacts on the durability and service life of the structures. In this paper, site data was gathered, which was used to perform a numerical and a finite element modelling to investigate the impacts of several conditions on thermal cracking in a structure. The field recorded data was used for the numerical modelling, using MATLAB software, and the finite element modelling, using ANSYS Mechanical software. It was observed that among the conditions considered, the wall ratio in the structure and formation of microcracks have significant impacts, while the age of the structure, the compressive strength of the concrete have minimal impacts, as the shifting in the curve is small. Finally, a probabilistic crack development model was made to study the potential crack development in the finite element model, which was seen to tally with observed site data, demonstrating the potential of predicting cracks development.
A Further Milestone to the Use of Natural Fibres in Concrete – Past Findings, Barriers and Novel Research Avenues
Authors: Raghoo Yashy , Ramasawmy Hareenanden , Gooroochurn Mahendra , Chummun Jaykumar , Seeboo Asish , Brown Neil 
Published: December 2021

Abstract
Concrete as a building material is much appraised for its good compressive strength; however, its low tensile strength makes it a quasi-brittle material. Experiments have proven that fibres such as steel and some polymeric fibres can reinforce and enhance the mechanical strength of concrete. The relatively high production cost of these fibres coupled with environmental issues for their end of life disposal and decline in mechanical strength beyond a certain fibre fraction have encouraged the use of natural fibres; particularly due to their renewability, low cost and good tensile strength. This paper reviews published literature in the field of natural fibres, their extraction methods as well as their effect on the mechanical properties of concrete. Alkaline fibre treatment to improve strength, wettability and subsequently, fibre-concrete matrix interfacial adhesion has also been discussed. As part of the research, the current authors have found that by just using untreated (raw) fibres as reinforcement in fact leads to a decline between 75 % and 90% in compressive strength tested at 8 days for 2 different fibre lengths and volume fractions, respectively. This decline in strength could be co-related with the phenomenon of fibre agglomeration as seen from microscopic analysis. As such, fibre treatment, to remove different impurities from its surface, constitutes an important step towards the manufacture of natural fibre-reinforced concrete. Furthermore, water adjustment in relation to the total water requirement of the cement, aggregates and water needed to saturate the plant fibres is an important property that requires proper control since water content has a direct impact on the workability of the concrete and can turn into a major constraint. The main challenge of the use of natural fibres in concrete is its degradation with time within the highly alkaline concrete environment. Accelerated ageing experiments for natural fibres in concrete as described in literature have confirmed this deleterious occurrence. Thus, as per findings from the current experimental works and literature, the following recommendations are proposed: natural fibre pre-processing to inhibit agglomeration, adequate water addition to cater for all the constituents of the reinforced concrete and the potential implementation of biomimicry to solve the fibre degradation problem.
Wood flooring in combination with underfloor heating systems
Authors: Kankovsky Ales , Dedic Martin 
Published: December 2021

AbstractThe main objective of the article is to inform about the wood flooring in combination with underfloor water heating systems. Wood is a very sensitive material that responds to its surroundings. For this reason, it is necessary to select a suitable wood, meeting the criteria of suitability for laying as flooring in combination with underfloor heating systems. It is also important to comply with the conditions of storage of wooden flooring and its installation under acceptable climatic conditions at the construction site, together with the technical regulations for the installation of wooden flooring in combination with underfloor heating systems, during the whole life cycle of the wood flooring. This article defines the basic input premise for the implementation of wooden floors in combination with underfloor heating systems, regarding the relevant technical standards and technological procedures valid in the Czech Republic. At the same time, the article describes possible failures of wooden floors in case of non-compliance with the above conditions. In the conclusion, we propose measures based on the described installation process failures of the wooden flooring in combination with underfloor heating systems, and after its use.