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Abstract

Local scour poses a grave threat to bridge foundations, potentially causing catastrophic collapses. This study uses FLOW-3D with the Reynolds-Averaged Navier-Stokes model to analyze pier scour and dune formation under bridges. It focuses on submerged debris shapes near the water's surface. Results closely match experiments when specific conditions are met. The study introduces an innovative approach to debris impact assessment. Instead of traditional methods, it proposes a novel equation accounting for debris's effective area and elevation. This enhances reliability by over 20%, improving scour depth assessment in debris-laden scenarios. This advances the understanding of debris's role in local scour, benefiting bridge design and management practices.

Open access

Abstract

Present paper shows the different types of tensor product model based linear matrix inequality controller design and feasibility analysis of two degrees of freedom aeroelastic wing section model. The tensor product models are based on reducing or removing the nonlinear behavior of the system and weighting functions. The linear matrix inequality based method results globally asymptotically stable system. The goal of the paper is to examine that selecting and varying the transformation space influences the feasibility of the linear matrix inequality based controller. The paper gives a comparison between the different tensor product models in terms of controller performance. The linear matrix inequality gives feasible solution for the controller design if the transformation space is selected adequately.

Open access

Endeavor for Self-Realization

The Story of Three Czech Professors of Architecture at the Slovak Technical University

Törekvés az önmegvalósításra

Három cseh építészprofesszor története a Szlovák Műszaki Egyetemen
Építés - Építészettudomány
Authors:
Jana Pohaničová
,
Matúš Dulla
, and
Nina Bartošová

This paper focuses on the reactions of three professors and architects (Jan E. Koula, Vladimír Karfík, and Alfred Piffl) to how the totalitarian political regime restricted and interfered with creative and academic freedoms in the period starting with the introduction of architectural education at the Slovak University of Technology and ending with the so-called “normalization” period in the former Czechoslovakia. All three of them were already active in interwar Czechoslovakia and thus had rich experience with working under democratic conditions, and their early work was influenced by the interwar avant-garde movements. After World War II, in part thanks to their pioneering work at the Slovak University of Technology, they got caught up in the system of the authoritarian socialist state. The central question that this study asks is how the trio dealt with the totalitarian regime, which stood in contrast with the democratic period of interwar Czechoslovakia that formed them as architects, and brought further limits to their work. Based mostly on material from their personal estates and period publications, we reveal how each of them found his own way to deal with the totalitarian regime, and we argue that even its limitations did not make Koula, Karfík, and Piffl abandon their beliefs and creative credos completely.

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Az építésautomatizálás technológiai lehetőségei

Az ipar 4.0 szemlélet kibontakozása az építőiparban

The Technological Opportunities of Construction Automation

The Development of the Industry 4.0 Approach in the Construction Industry
Építés - Építészettudomány
Authors:
István Vidovszky
and
Tamás Szögi

Az építőipar a munkaerő hiánya és az egyre fokozódó minőségi elvárások miatt a hagyományos, jellemzően emberi erőforrást alkalmazó vagy emberek által közvetlenül működtetett technológiák irányából apró lépésenként az automatizált technológiák irányába fordul. Az ezzel együtt járó változás csak úgy lehet zökkenőmentes, ha az építőipar résztvevői aktív részesei a változási folyamatnak. A cikk az építőipar fejlődési irányait, annak problematikáját és lehetőségeit kívánja bemutatni a területtel kapcsolatos kutatások és a már alkalmazott technológiai megoldások elemzésével a közeljövőben lehetséges változások, további lehetőségek, illetve problémák feltérképezésére és megvilágítására törekedve.

Open access

Abstract

Integrating thermal energy storage with thermal conversion systems is necessary to maximize their use. Phase change materials are the best media for storing and releasing thermal energy from various basic material types. Because the phase change materials have a high latent heat of fusion, it is often viable to use these characteristics and include the phase change materials in building envelopes to store thermal energy. The paper provides a thorough categorization of the phase change materials and thermal energy storage systems, in addition to an evaluation of their modeling using computational fluid dynamics. The purpose was to highlight computational fluid dynamics as a useful technique for advancing the engineering of thermal energy storage devices.

Open access

Abstract

This study evaluated the thermal performance of side divergence and uniform micro-channel heat sinks by comparing and contrasting them. Heat transfer and fluid flow characteristics in these micro-channel configurations were studied using computational fluid dynamics simulations employing ANSYS Fluent 2017 code for this purpose. Laminar flow through micro-channels with a Reynolds number of 207 was the subject of the investigation. The goal is to determine how side divergence affects heat dissipation efficiency concerning traditional uniform micro-channels. The results showed that the best divergence ratio is 1.5 that achieved the highest performance. The study also revealed that side divergence micro-channel heat sinks can achieve thermal performance up to 14% higher than uniform micro-channel heat sinks.

Restricted access
Pollack Periodica
Authors:
Orest Voznyak
,
Nadiia Spodyniuk
,
Iryna Sukholova
,
Olena Savchenko
,
Mariana Kasynets
, and
Serhii Shostak

Abstract

This article is dedicated to diagnosis of damage to air distribution in a room with twisted, compact, and flat air jets, and to searching of ways to solving the problem. It was found that in order to avoid damage to the air distribution system in rooms of different purposes and dimensions; it should be air streams of the appropriate types and with the appropriate characteristics. Parameters of a swirled, compact, flat, rectangular air jet when creating comfortable climatic conditions in the rooms of different purposes and dimensions are determined. The relationship between the angle of inclination of the rotating plates (for twisted jets), ratio of sides of the slit (for all rectangular including compact and flat streams) and a long-range of these flows is established.

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Pollack Periodica
Authors:
Maher F. Al Lebban
,
Ameer A. Alraie
,
Qusay A. Jabal
,
Laith Abdul Rasool Alasadi
,
Rawa Shakir Muwashee
, and
Waseem H. Mahdi

Abstract

Progress in building construction requires more durable concrete with higher strength. Polymer and water reducer liquids can improve concrete strength and durability. This research aims to improve the mechanical properties of polymer-modified concrete by using anti-slip sand and silica fume to achieve more durable concrete against sulfate attack and higher mechanical properties. The study shows an increase in compressive strength from 25.7 MPa for reference mix to 45.5 MPa using 15% silica fume and 30% Anti-slip sand; tensile strength increased from 2.72 to 4.4 MPa. Flexural strength also increased, and durability to sulfate attack also increased. The study includes the increment of durability against freezing-thawing cycles for different mixes.

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Abstract

Direct resistance check by applying advanced numerical models is getting increasingly used for the design of steel slender plated structures. This method has to take into account the same uncertainties as traditional analytical design calculations and should ensure the Eurocode-based prescribed safety level. The application of the model factor gives the possibility to account for the model-related uncertainties. The current study focuses on the determination of the model factor for one specific failure mode, the patch loading resistance. Numerical model has been developed and validated based on laboratory test results. To evaluate the model uncertainties, physically possible modeling differences are introduced, and their effects are evaluated on the resistance. The final aim of the study is to determine the model factor for the analyzed girder type and failure mode based on statistical evaluation.

Open access

Abstract

Warping not only one of the most important phenomena in steel section it is also considered as the most complicated phenomena. Ductility, bearing capacity and serviceability of steel sections may affect by increasing stress concentration of the normal stresses due to warping. In the present work, simulation of steel beam section under effect of warping is studied. Two cantilevers connected to two columns in opposite sides with a middle steel beam-column connection to create different moments on the beam to investigate the behavior of steel section under warping using building information modeling. It is found that the stress strain relationship has four groups depending on the load intensity and the angle of rotation induced due to warping.

Restricted access