Statická analýza zastřešení sportovní haly
Meissnerová, Sabina; Hokeš, Filip; Vlk, Zbyněk
2024 - Czech Diplomová práce se zabývá statickou analýzou zastřešení sportovní haly. Výpočtový model byl dle poskytnutých podkladů vytvořen ve výpočetním programu Dlubal RFEM 6.04. Bylo provedeno zatížení dle platných norem a konstrukce posouzena na mezní stav únosnosti a pevnosti. Ruční výpočty posouzení byly porovnány s programem. V diplomové práci je řešen ruční výpočet vnitřních sil na zaobleném nosníku od vlastní tíhy konstrukce a stabilita konstrukce demonstrována nejprve na jednostranně vetknutém nosníku poté na vytvořeném prostorovém modelu. The final thesis deals with structural analysis of the roofing of the sports hall. Computational model was created in the computational software Dlubal RFEM 6.04 according to the provided documents. The loads were performed in accordance with valid standards and the structure was assessed for the ultimate and serviceability limit state. Manual assessment calculations were compared with the software. The final thesis deals with the manual calculation of internal forces on a curved beam from the self-weight of the structure and the stability of the structure is demonstrated first on a single-sided fixed beam and then on the created spatial model. Keywords: Ocelová konstrukce; model; střecha; zakřivený nosník; příhradový vazník; zatížení; kombinace zatěžovacích stavů; statická analýza; stabilita; Steel structure; model; roof; curved beam; truss girder; loads; load case combinations; structural analysis; stability Available in a digital repository NRGL Statická analýza zastřešení sportovní haly

Diplomová práce se zabývá statickou analýzou zastřešení sportovní haly. Výpočtový model byl dle poskytnutých podkladů vytvořen ve výpočetním programu Dlubal RFEM 6.04. Bylo provedeno zatížení dle ...

Meissnerová, Sabina; Hokeš, Filip; Vlk, Zbyněk
Vysoké učení technické v Brně, 2024

Požární stanice
Kaňa, Josef; Kacálková, Lenka; Kacálek, Petr
2024 - Czech Diplomová práce pojmenovaná Hasičská stanice, řeší projektovou dokumentaci na úrovni dokumentace provádění stavby pro hasičskou stanici. Stavba je umístěna na okraji Holešova v části s názvem Všetuly. Stavba je umístěna v těsné blízkosti stávajícíh výrobních závodů, místní průmyslové zóně, do které je umožněn příjezd mimo město a blízko nájezdu na budovanou D49 a část městského obchvatu. Projekt se zabývá umístěním stavby na pozemku včetně zpevněných ploch a jejich napojení na stávající komunikace, v rámci projektu je také počítáno s umístěním sportovišť pro fyzickou přípravu. Objekt je navržen jako dvoupodlažní s pěti stáními pro zásahová vozidla, kdy tento prostor probíhá přes obě podlaží. V 1.NP je navržené technické zázemí stanice se sklady a špinavou šatnou. V 2.NP jsou navrženy místnosti pro pohotovost a kanceláře sloužících hasičů s hygienickým zázemím. Stanice je navržena podle zákona o požární ochrany velikosti P2 pro jednotku kategorie JPO I s počtem 24 sloužících hasičů ve třech směnách. V rámci návrhu bylo uvažováno s vozidly u stávající jednotky AZ – 30 M1Z Novus, CAS 3 – T815, CAS 20 – S2Z MB, KHA, TA – MAN, Škoda Kamiq. The diploma thesis named Fire Station deals with project documentation at the level of construction execution documentation for a fire station. The building is located on the outskirts of Holešov in the part called Všetuly. The building is located in close proximity to the existing production plants, the local industrial zone, which is accessible from outside the city and close to the approach to the under-construction D49 and part of the city bypass. The project deals with the location of the building on the land, including paved areas and their connection to existing roads, the project also includes the location of sports fields for physical training. The building is designed as a two-story building with five parking spaces for emergency vehicles, where this space extends over both floors. On the 1st floor, the technical facilities of the station with storage and a dirty changing room are designed. On the 2nd floor, emergency rooms and offices of serving firefighters with hygienic facilities are designed. The station is designed according to the Fire Protection Act size P2 for a JPO I category unit with 24 serving firefighters in three shifts. As part of the proposal, vehicles at the existing unit were considered AZ – 30 M1Z Novus, CAS 3 – T815, CAS 20 – S2Z MB, KHA, TA – MAN, Škoda Kamiq. Keywords: Hasičská stanice; plošné základy; monolitický skelet; plochá jednoplášťová střecha; skluz; vjezd do garáže; vstup do objektu; vtok s bezpečnostním přepadem; Fire station; flat founfations; monolithic skeleton; flat single skon roof; chute; entrance to the garage; entrance to the building; inlet with safety overflow Available in a digital repository NRGL Požární stanice

Diplomová práce pojmenovaná Hasičská stanice, řeší projektovou dokumentaci na úrovni dokumentace provádění stavby pro hasičskou stanici. Stavba je umístěna na okraji Holešova v části s názvem Všetuly. ...

Kaňa, Josef; Kacálková, Lenka; Kacálek, Petr
Vysoké učení technické v Brně, 2024

Numerické optimalizační metody
Lukšan, Ladislav
2024 - Czech Tato zpráva popisuje teoretické i praktické vlastnosti numerických metod pro nepodmíněnou optimalizaci. Studují se metody pro obecné i speciální optimalizační úlohy, mezi které patří minimalizace součtu čtverců, součtu absolutních hodnot, maximní hodnoty a dalších nehladkých funkcí. Kromě metod pro standardní úlohy středních rozměrů jsou studovány i metody pro rozsáhlé řídké a strukturované úlohy. Velká pozornost je věnována soustavám nelineárních rovnic.\n Keywords: Numerická optimalizace; nelineární aproximace; systémy nelineárních rovnic; algoritmy Available on request at various institutes of the ASCR Numerické optimalizační metody

Tato zpráva popisuje teoretické i praktické vlastnosti numerických metod pro nepodmíněnou optimalizaci. Studují se metody pro obecné i speciální optimalizační úlohy, mezi které patří minimalizace ...

Lukšan, Ladislav
Ústav informatiky, 2024

Difuzní vlastnosti OSB desek v důsledku zasažení nadměrnou vlhkostí.
Žižková, Lucie; Vertal', Marián; Chybík, Josef; Bečkovský, David
2024 - Czech Předložená disertační práce pojednává o změně difuzních vlastností u desek z orientovaných plochých třísek (OSB) po zasažení nadměrnou vlhkostí. OSB desky po zasažení nadměrnou vlhkostí a následném vysušení změní své difuzní vlastnosti, a tak díky odlišnému faktoru difuzního odporu již neodpovídají původnímu návrhu skladby stěny dřevostavby. Cílem práce je popsat změnu difuzních vlastností laboratorně změřenou a tuto zakomponovat do reálné skladby stěny dřevostavby a posoudit její funkci pomocí počítačové simulace. Úvod práce tvoří teoretický základ pro zpracování experimentální části, ve které je obsaženo měření nasákavostí, difuzních vlastností a rizika růstu plísní. V experimentální části jsou popsány přístupy a metody k naplnění cíle disertační práce. Měření probíhalo v laboratořích ústavu pozemního stavitelství na zkušebních vzorcích z OSB desek. Po zasažení nadměrnou vlhkostí byly zkušební vzorky vysušeny pomocí dvou vysoušecích metod. Vysušené zkušební vzorky byly umístěny do zkušebních sestav, na kterých byla měřena difuze metodou suchých misek. Měření probíhalo ve dvou etapách, kdy v každé z výzkumných etap bylo měřeno na více než 80 vzorcích. V závěrečné části je měření vyhodnoceno formou grafů. Změna difuzních vlastností byla poté zakomponována do reálné skladby stěny dřevostavby a za pomoci počítačové simulace, která je v praxi nerozšířenější, dle ČSN 73 0540 posouzena. The presented dissertation focuses on the change of diffusion properties in oriented strand board (OSB) panels after exposure to excessive moisture. OSB panels undergo a change in their diffusion properties after being affected by excessive moisture and subsequently dried, causing them to deviate from the original design of the wooden wall structure. The aim of this study is to describe the experimentally measured change in diffusion properties and incorporate it into the composition of a real wooden wall structure, evaluating its performance through computer simulation. The introduction of the dissertation provides the theoretical basis for the experimental section, which includes measurements of water absorption, diffusion properties, and the risk of mold growth. The experimental section describes the approaches and methods used to achieve the objectives of the dissertation. The measurements were conducted on test samples of OSB panels in the laboratories of the Institute of Civil Engineering. After being exposed to excessive moisture, the test samples were dried using two drying methods. The dried test samples were placed in testing assemblies, where diffusion was measured using the dry cup method. The measurements were carried out in two stages, with more than 80 samples measured in each research stage. In the final part, the measurements are evaluated through graphs. The change in diffusion properties was then incorporated into the composition of a real wooden wall structure and assessed using computer simulation, which is more commonly used in practice according to ČSN 73 0540 (Czech Technical Standard). Keywords: Difuze; vlhkost; OSB desky; dřevostavby; dřevo; plísně; vlhkost materiálu; nadměrná vlhkost; EMW metoda; mikrovlnné záření; vysoušení; konstrukce; faktor difuzního odporu; zkušební vzorek.; Diffusion; moisture; oriented strand boards (OSB); timber structures; wood; mold; moisture of material; excessive humidity; EMW method; microwave radiation; drying; construction; diffusion resistence factor; test sample. Available in a digital repository NRGL Difuzní vlastnosti OSB desek v důsledku zasažení nadměrnou vlhkostí.

Předložená disertační práce pojednává o změně difuzních vlastností u desek z orientovaných plochých třísek (OSB) po zasažení nadměrnou vlhkostí. OSB desky po zasažení nadměrnou vlhkostí a následném ...

Žižková, Lucie; Vertal', Marián; Chybík, Josef; Bečkovský, David
Vysoké učení technické v Brně, 2024

Posouzení stavu a měření mechanických vlastností dřevěné konstrukce krovu a stropu 1. patra státního zámku Hrádek u Nechanic, rejstř. číslo kult. památky: 18278/6‐619
Kloiber, Michal; Drdácký, Miloš
2024 - Czech Available at various institutes of the ASCR Posouzení stavu a měření mechanických vlastností dřevěné konstrukce krovu a stropu 1. patra státního zámku Hrádek u Nechanic, rejstř. číslo kult. památky: 18278/6‐619

Kloiber, Michal; Drdácký, Miloš
Ústav teoretické a aplikované mechaniky, 2024

Flow simulations approach for flocculation tanks
Idžakovičová, Kristýna; Bílek, V.; Haidl, J.; Isoz, Martin; Pivokonský, M.
2024 - English Flocculation in water treatment facilities plays a key role in the separation of colloidal inorganic and organic substances. Its optimization leads to a significant increase in its efficiency and savings of operational costs. However, it is currently based on trial-and-error experimental approaches. In this contribution, we focus on flow modeling in stirred flocculation tanks that would, after coupling with a calibrated model of particle aggregation, enable simulationbased flocculation optimization. Despite the abundance of literature on stirred tank modeling, there is no universal agreement on the methodology used to describe turbulence nor on the approach to the computational mesh creation. Consequently, there is no unified methodology for simulations and their validation. To address this, we present a best-practice methodology for economical, yet reliable flow simulations in the said device. This methodology includes the choice of the turbulence model, the approach to the design of a high quality mesh suitable for arbitrary geometries, and results evaluation. It is developed based on an extensive literature review, a multitude of flow simulations using several meshes of progressively higher quality and resolution, and various strategies to converge to steady-state flow conditions. The simulation quality indicators used here involve comparison with the experimental data on fluid velocity, stirrer power output, and flow rate through the impeller zone. Additionally, the resulting flow simulation models are compared using tracer transport simulations, hinting at their potential for coupling with particle aggregation models. Keywords: flocculation tank; stirring; MRF; CFD; OpenFOAM Available at various institutes of the ASCR Flow simulations approach for flocculation tanks

Flocculation in water treatment facilities plays a key role in the separation of colloidal inorganic and organic substances. Its optimization leads to a significant increase in its efficiency and ...

Idžakovičová, Kristýna; Bílek, V.; Haidl, J.; Isoz, Martin; Pivokonský, M.
Ústav termomechaniky, 2024

A New Hollow Fiber-Based Liquid-Phase Microextraction Method for the Determination of Antihypertensive Drug Lercanidipine in Biological Samples
Labzova, O.; Hrdlička, Vojtěch; Navrátil, Tomáš; Šelešovská, R.
2024 - English A new hollow fiber-based liquid-phase microextraction (HF-LPME) method for the determination of antihypertensive drug lercandipine (LCN) in biological samples was developed. HF-LPME was\ncombined with optimized square wave voltammetry (SWV) on a cathodically pre-treated screenprinted boron-doped diamond electrode (SP-BDDE). Optimum HF-LPME conditions were:\nsupported liquid membrane (SLM) dodecane, 0.02 mol L-1 Britton-Robinson buffer (BRB, pH = 3) acceptor phase, BRB (pH = 7) donor phase, and time of extraction 30 min. Limits of quantification (LOQ) and detection (LOD) were 3.3 and 1.1 nmol L-1, respectively. The applicability of the developed method was verified on human urine, blood serum, and blood plasma with 20 and 100 nmol L-1 LCN addition. Keywords: Lercanidipine hydrochloride; Hollow fiber liquid-phase microextraction; Screenprinted boron-doped diamond electrode Available on request at various institutes of the ASCR A New Hollow Fiber-Based Liquid-Phase Microextraction Method for the Determination of Antihypertensive Drug Lercanidipine in Biological Samples

A new hollow fiber-based liquid-phase microextraction (HF-LPME) method for the determination of antihypertensive drug lercandipine (LCN) in biological samples was developed. HF-LPME was\ncombined with ...

Labzova, O.; Hrdlička, Vojtěch; Navrátil, Tomáš; Šelešovská, R.
Ústav fyzikální chemie J. Heyrovského, 2024

Influence of ball material on the resulting fatigue life of thermal sprayed HVOF coatings in dynamic impact testing
Duliškovič, J.; Daniel, Josef; Houdková, Š.
2024 - English Dynamic impact wear, i.e. contact between two components in the presence of high cyclic local loads, is a challenging failure mode that occurs in many mechanical applications. Many previous studies have confirmed that dynamic impact testing is suitable for evaluating the contact fatigue of thermal sprayed coatings. However, the effect of the test parameters on the resulting lifetime is unclear. The aim of this study describes the effect of the ball material used in the dynamic impact test on the resulting fatigue life of the HVOF thermal sprayed coating. Three test balls made of WC/Co alloy, Si3N4 silicon nitride and 440 C steel were chosen for this study. Dynamic impaction testing was carried out on the Cr3C2-NiCr coating, which was sprayed by HVOF on a 1.2376 high-speed steel substrate. The impact lifetime was described by the number of critical impacts, i.e. the number of impacts before coating fatigue occurs. Furthermore, the depth and volume of impact craters were measured. Using scanning electron microscopy (SEM), the surface of the impacts as well as the microstructure of the coating on the cross-section in the region of the impacts were observed. Furthermore, the mechanism of crack propagation in the coating and the microstructure of the indentor were investigated. Keywords: dynamic impact test; HVOF; Cr3C2-NiCr; fatigue Available at various institutes of the ASCR Influence of ball material on the resulting fatigue life of thermal sprayed HVOF coatings in dynamic impact testing

Dynamic impact wear, i.e. contact between two components in the presence of high cyclic local loads, is a challenging failure mode that occurs in many mechanical applications. Many previous studies ...

Duliškovič, J.; Daniel, Josef; Houdková, Š.
Ústav přístrojové techniky, 2024

Functional Tungsten-based thin films and their characterization
Košelová, Zuzana; Horáková, L.; Sobola, Dinara; Burda, Daniel; Knápek, Alexandr; Fohlerová, Z.
2024 - English Anodizing is a technique by which thin oxide layers can be formed on a surface. Thin oxide layers have been found to be useful in a variety of applications, including emitters of electrons. Tungsten is still a common choice for cold field emitters in commercial microscopy applications. Its suitable quality can be further improved by thin film deposition. Not only the emission characteristic can be improved, but also the emitter operating time can be extended. Tungsten oxide is known for its excellent resistance to corrosion and chemical attack due to its stable crystal structure and strong chemical bonds between tungsten and oxygen atoms. Many techniques with different advantages and disadvantages have been used for this purpose. Anodization was chosen for this work because of the controllable uniform coverage of the material and its easy availability without the need for expensive complex equipment. The anodizing process involves applying an electrical potential to tungsten while it is immersed in an electrolyte solution. This creates a thin layer of tungsten oxide on the surface of the metal. The thickness and properties of the resulting oxide layer can be controlled by adjusting the anodization conditions, such as the electrolyte solution, voltage, and the duration of the process. In this work, H3PO4 was used as the electrolyte to test whether these tungsten oxide layers would be useful for electron emitters, for use in electron guns and other devices that require high-quality electron emitters. The properties were evaluated using appropriate techniques. In general, anodization of tungsten to form thin layers of tungsten oxide layers is a promising technique for producing high quality electron emitters. Keywords: cold-field emission; thin layer deposition; tungsten oxide; resonance enhanced tunneling; anodization Available at various institutes of the ASCR Functional Tungsten-based thin films and their characterization

Anodizing is a technique by which thin oxide layers can be formed on a surface. Thin oxide layers have been found to be useful in a variety of applications, including emitters of electrons. Tungsten ...

Košelová, Zuzana; Horáková, L.; Sobola, Dinara; Burda, Daniel; Knápek, Alexandr; Fohlerová, Z.
Ústav přístrojové techniky, 2024

Microstructure modifications of Al-Si-coated press-hardened steel 22MnB5 by laser welding
Šebestová, Hana; Horník, Petr; Mika, Filip; Mikmeková, Šárka; Ambrož, Ondřej; Mrňa, Libor
2024 - English Weld microstructure depends on the characteristics of welded materials and parameters of welding technology, especially on the heat input that determines the peak temperature and the cooling rate. When the coated sheets are welded, the effect of the chemical composition of the coating must be also considered even though its thickness is only a few tens of microns. During 22MnB5+AlSi laser welding experiments, the ferrite-stabilizing elements of coating modified the weld metal microstructure. Ferrite appeared in a quenched weld metal. The rapid cooling rate accompanying welding with a focused beam limited the homogenization of the weld metal which resulted in the formation of ferritic bands in the regions rich in Si and especially in Al. On the other hand, a high level of homogenization was reached when welding with the defocused beam. The ferritic islands uniformly distributed in the weld metal were formed at 0.4 wt% and 1.6 wt% of Si and Al, respectively. The doubled heat input reduced the Al content to 0.7 wt% insufficient for the ferrite formation at still relatively high cooling rates. Predicting the distribution of ferrite in the weld metal is challenging due to its dependence on various factors, such as cooling rate and the volume of dissolved coating, which may vary with any modifications made to the welding parameters. Keywords: laser welding; high-strength steel; microstructure; heat input; ferrite stabilization Available at various institutes of the ASCR Microstructure modifications of Al-Si-coated press-hardened steel 22MnB5 by laser welding

Weld microstructure depends on the characteristics of welded materials and parameters of welding technology, especially on the heat input that determines the peak temperature and the cooling rate. ...

Šebestová, Hana; Horník, Petr; Mika, Filip; Mikmeková, Šárka; Ambrož, Ondřej; Mrňa, Libor
Ústav přístrojové techniky, 2024