Unwinding and Winding Unit for Foils

Import 02/11/2016Diplomová práce se zabývá konstrukčním návrhem odvíjecího zařízení na pěnovou balící fólii. Zařízení bude umožňovat i obrácený proces – navíjení fólie. Při odvíjecím režimu je role s fólií automaticky nasunuta na pneumatickou hřídel, zajištěna a přesunutá do polohy odvíjení. Po odvinutí fólie je obsluhou sejmuta papírová špulka. Při opačném procesu navíjení je na pneumatickou hřídel obsluhou nasunuta papírová špulka na pneumatickou hřídel a upnuta. Po uchycení fólie na špulku se zajistí pneumatická hřídel a začne navíjecí proces. Po navinutí fólie je celá role automaticky sesunuta z hřídele a připravena pro další manipulaci.My diploma thesis focuses on a construction design of a foam foil unrolling device. The device will also be able to do a reverse process – foil reeling. After the unrolling mode, the foil is automatically put onto a pneumatic shaft, locked in and moved to unrolling position. After the foil is unrolled, the handling crew removes the paper spool. During the reverse process – foil reeling, the paper spool is put onto the pneumatic shaft by the handling crew and then clamped. After the foil is clamped onto paper spool, the pneumatic shaft locks it in and starts the reeling process. After the foil is rolled, the finished foil roll is automatically displaced from the shaft and is ready for further manipulation.340 - Katedra výrobních strojů a konstruovánívýborn

Study of Influence Roughness Steel Substrate on Adhesion Thin Skin of Paint System

Import 05/08/2014V teoretické části bakalářské práce jsou popsány povrchové úpravy před nanesením nátěrového systému, povrch a jeho vlastnosti. Dále hodnocení drsnosti povrchu a přilnavost substrátu. V experimentální části je hodnocena přilnavost nátěrového systému k otryskaným materiálům a to dvěma způsoby, mřížkovou zkouškou a odtrhovou zkouškou. Výsledky měření jsou uvedeny v tabulkách a z výsledků experimentálních zkoušek vyplývá, že více vyhovoval substrát z litinové drti, který měl lepší přilnavost.In the theoretical part of the thesis is describes the surface treatment prior to application of the coating system, surface and its properties. Further evaluation of surface roughness and adhesion substrate. In the experimental part of the thesis is assessment of adhesion of the coating system to blasting materials in two ways, cross-cut test and tear test. The measurement results are shown in tables, and the results of experimental tests that the more suited the substrate of blast units which have a better adhesion.345 - Katedra mechanické technologievelmi dobř

Study of Post-Discharge Processes

V této práci bylo studováno dohasínající plazma pomocí optické emisní spektroskopie. Výboj v proudícím režimu byl vytvářen stejnosměrným proudem 45 až 200 mA v Pyrexové a křemenné trubici. Emise tří spektrálních systémů dusíku (1. a 2. pozitivní a 1. negativní) byly studovány v časovém vývoji s ms rozlišením pro různé tlaky 500 až 5 000 Pa; za normální a kapalným dusíkem chlazené teploty stěny (za chlazení bylo v dohasínajícím plazmatu 150 K). Výsledky ukázaly, že všechny tři dusíkové systémy (respektive jejich horní stavy N2(B, v), N2(C, v) a N2+(B, v)) mají maximální hodnoty v dohasínání v tzv. „pink-afterglow“. Tato maxima klesala s rostoucím tlakem a posouvala se k pozdějším časům dohasínání. Maxima rostla s výbojovým proudem (respektive výkonem) a posouvala se ke kratším časům dohasínání. Intenzity a z nich vypočtené vibrační populace za teploty 150 K byly určovány v experimentálním zařízení od 17 ms, a proto nebylo pozorováno maximum „pink-afterglow“ (jen při 5 000 Pa se objevil jeho náznak). Populace byly menší za 150 K než populace měřené za laboratorní teploty v časech okolo 50-100 ms. Za nížšího tlaku a v pozdním čase (přes 120 ms) byly populace vyšší za nižší teploty. V křemenné trubici byly oba posuny maxim populací výraznější než v Pyrexové trubici. Kromě populací byly také stanoveny rotační teploty těchto vybraných pásů všech tří měřených spektrálních systémů (pro 1. negativní systém pás 0-0, pro 1. pozitivní systém pás 2-0 a pro 2. pozitivní systém pás 0-2). Rotační teploty byly monitorovány z předpokladu, že tento druh teploty je roven teplotě neutrálního plynu (za podmínky lokální termodynamické rovnováhy). Výsledky pro 1. negativní a 1. pozitivní systém ukazují, že na začátku dohasínání (do cca 10 ms) dochází k prudkému poklesu rotačních teplot, pak teploty byly konstantní do 20 ms a poté teploty rostly. Tento průběh byl tedy v podstatě opačný než průběh intenzit u těchto spektrálních systémů. Rotační teploty podle očekávání mírně rostly s rostoucím proudem. V případě teploty vypočtené z 2. pozitivního systému byla pozorována špatná reprodukovatelnost výsledků, lze ale vypozorovat zřetelný nárůst teploty v oblasti „pink-afterglow“. Experimentální výsledky byly konfrontovány s numerickým kinetickým modelem vytvořeným skupinou prof. Vasca Guerry na Instituto Superior Técnico v Portugalsku. Pro kalkulaci korespondující s experimentem bylo nalezeno několik souborů podmínek pro simulaci za teplot 500 a 1 000 K v aktivním výboji. Srovnání numerické simulace a experimentálních dat pro stav N2(B) ukázalo, že maxima populací v „pink-afterglow“ jsou závislá na teplotním rozdílu mezi aktivním výbojem a dohasínajícím výbojem. Teoretická maxima populací v „pink-afterglow“ dokonce zmizela v případě, že teploty v aktivním výboji a v dohasínaání byly stejné. Výsledky jasně ukazují, že reálný teplotní profil musí být zahrnut do kinetického modelu.The decaying plasma was studied by the optical emission spectroscopy. DC discharge created at 45 – 200 mA in Pyrex and Quartz tubes in flowing regime was used. The emission of three nitrogen spectral systems (1st and 2nd positive and 1st negative) were studied in time evolution for pressures of 500 – 5 000 Pa at two wall temperatures – ambient and liquid nitrogen (150 K inside the decaying plasma). Results showed that all three nitrogen systems (respectively N2(B, v), N2(C, v) and N2+(B, v) states as their origins) had their population maxima called pink-afterglow in the afterglow part. These maxima decreased with the increase of pressure for all systems, and moved to the later decay time. Maxima increased with discharge current (respectively power) and moved to shorter time. Populations at temperature of 150 K were measured due to the experimental arrangement from 17 ms, only, and thus pink aftergow maximum wasn’t observed (only at 5 000 Pa some maximum was recognized). Populations were smaller at 150 K that populations measured at laboratory temperature at the middle decay time (50-100 ms). At the late time, the populations were higher at lower temperature at lower pressure. Higher shifts (in intensity and decaytime) of pink afterglow maxima were observed in Quartz tube in comparison with their values in Pyrex tube. Besides the populations, rotational temperatures of selected bands of three observed spetral systems (for 1st negative 0-0 band, 1st positive 2-0 band and for 2nd positive 0-2 band) were measured. Rotational temperatures were monitored from presumption that this kind of temperature is equal to temperature of neutral gas (at local thermodynamic equilibrium). Results from 1st negative and 1st positive system showed strong decreasing of rotational temperatures up to about 10 ms at post-discharge begin, then temperatures were constant up to 20 ms of decay time and after that they grew up. Temperatures increased with the increase of current. The part with decreased temperature correlated with pink-afterglow part of post-discharge. Unfortunately, rotational temperatures of 2nd positive system had bad reproducibility and the time profile shape was opposite. Experimental results were compared with numerical kinetic model created by group of prof. Vasco Guerra at Instituto Supetior Técnico in Portugal. Several sets of conditions for simulation at 500 and 1 000 K in active discharge were applicable for the calculation corresponding to the experiment. Comparison of numerical simulation and experimental data done for N2(B) state demonstrated that maxima populations in pink afterglow are depended on the temperature difference between active discharge and post discharge. Maxima populations were supposed in pink afterglow disappeared if the same temperatures in active and post discharges were supposed. Temperature in active discharge is higher at higher apllied power, as it was showed from rotational temperatures observation. The results clearly showed that real temperature profile must be included into the kinetic model.

Distribution of selected substances in blue varieties of table grapes

This study contains data of seven blue cultivars of table grape (Vitis vinifera L. and Vitis labrusca L.): Attika, Early Cardinal, Eszter, Chasselas rosé, Königliche Esther, Muscat bleu, and Nero. The following were determined in intact berries: malic, tartaric, and titratable acids, pH values, sugar content, and antioxidant capacity. Concentrations of the following compounds were determined in the pulp of a analysed berries: phenolic acids and catechins. The last analysis focused on skins; in addition to the same phenolic acids and catechins, excluding epicatechin, analysed from pulp; ferulic acid and stilbenes were also studied. Higher contents of procyanidin B2 and gallic acid were found in the pulp as compared to those found in skins. Studies during the ripening stage showed that the higher ratio of procyanidin B2 and gallic acid concentrations in the pulp vs. skins relates to late-ripening cultivars, while for early-ripening cultivars a lower ratio was observed. Contents of phenolic acids, catechin, stilbenes, and anthocyanins were studied by means of LC-DAD; other compounds were measured by FTIR

Study of Influence Roughness Metal Surface on Surface Properties

Import 02/11/2016Diplomová práce se zabývá studiem vlivu drsnosti kovového povrchu na vlastnosti povrchu. V teoretické části je popsána charakteristika povrchu, povrchové úpravy kovů a koroze. Experimentální část se zabývá studiem tlakových nádob, které se skládaly ze dvou částí a to ocelové a měděné. U ocelové otryskané části je stanovena čistota, drsnost povrchu a kotvící profil. Dále vady, které se vyskytly u těchto tlakových nádob, mikrotvrdost, makrostruktura a mikrostruktura. U měděné trubky je zkoumána mikrotvrdost, mikrostruktura a v poslední řadě důvod výskytu galvanické koroze. Návrh metodiky prací a vyhodnocení provedených zkoušek jsou zpracované ve formě grafů, tabulek a fotografií.This master thesis deals Study of Influence Roughness Metal Surface on Surface Properties. The theoretical part describes the characteristics of the surface, metal coatings and corrosion. The experimental part describes the study of pressure vessels, which consists of two parts, steel and copper. For blasted steel part are determined purity, surface roughness and blasting profile. Furthermore defects that have occurred in these pressure vessels, micro-hardness, macrostructure and microstructure. For copper pipe are examined microhardness, microstructure and last reason for the occurrence of galvanic corrosion. Proposed methodology of work and evaluation of tests are presented in the form of diagrams, tables and photos.345 - Katedra mechanické technologievelmi dobř

Colour and antioxidant properties of malvidin-3-glucoside and Vitisin A

This study presents findings from comparing the properties of anthocyanin pigments: i. malvidin-3-glucoside (Mal-3-G), the most significant anthocyanin present in young red wine; ii. Vitisin A (5-carboxypyranomalvidin-3-glucoside), a major product from a reaction induced in red wine between Mal-3-G and pyruvic acid during its ageing. These pigments were determined and compared to the absorption spectrum in 200–770 nm at various pH values, such results including the ability of cation Al3+ to change the values of absorbance. Changes in the colour parameters L* a* b* were determined in the CIELAB colour space of Mal-3-G and Vitisin A in relation to pH and the addition of AlCl3. Both coloured compounds were investigated for their resistance to discoloration by sulphur dioxide. Total antioxidant activity was evaluated by two methods (FRAP, DPPH), and the values were compared to other phenols

Hydrogel Containing Anti-CD44-Labeled Microparticles, Guide Bone Tissue Formation in Osteochondral Defects in Rabbits

Hydrogels are suitable for osteochondral defect regeneration as they mimic the viscoelastic environment of cartilage. However, their biomechanical properties are not sufficient to withstand high mechanical forces. Therefore, we have prepared electrospun poly-ε-caprolactone-chitosan (PCL-chit) and poly(ethylene oxide)-chitosan (PEO-chit) nanofibers, and FTIR analysis confirmed successful blending of chitosan with other polymers. The biocompatibility of PCL-chit and PEO-chit scaffolds was tested; fibrochondrocytes and chondrocytes seeded on PCL-chit showed superior metabolic activity. The PCL-chit nanofibers were cryogenically grinded into microparticles (mean size of about 500 µm) and further modified by polyethylene glycol–biotin in order to bind the anti-CD44 antibody, a glycoprotein interacting with hyaluronic acid (PCL-chit-PEGb-antiCD44). The PCL-chit or PCL-chit-PEGb-antiCD44 microparticles were mixed with a composite gel (collagen/fibrin/platelet rich plasma) to improve its biomechanical properties. The storage modulus was higher in the composite gel with microparticles compared to fibrin. The Eloss of the composite gel and fibrin was higher than that of the composite gel with microparticles. The composite gel either with or without microparticles was further tested in vivo in a model of osteochondral defects in rabbits. PCL-chit-PEGb-antiCD44 significantly enhanced osteogenic regeneration, mainly by desmogenous ossification, but decreased chondrogenic differentiation in the defects. PCL-chit-PEGb showed a more homogeneous distribution of hyaline cartilage and enhanced hyaline cartilage differentiation

Bioactive compounds recovery optimization from vine pruning residues using conventional heating and microwave-assisted extraction methods

Polyphenol compounds from vine pruning residue (VPR) were extracted by conventional heating and microwave-assisted treatments. For each treatment, total phenolic compounds and their antioxidant activity were optimized by experimental design. Maximal extraction of polyphenolic compounds (2.17g/100g VPR) was obtained at 80°C, 120min and 45% of ethanol by conventional heating, and 2.37g/100g of VPR were extracted by microwave-assisted process at 120°C, 5min and 60% of ethanol. Ellagic acid and apigenin were the predominant polyphenolic compounds in the extracts, achieving concentration of 68.65 and 208.23mg/100g VPR, respectively for conventional heating and 185.15 and 118.84mg/100g of VPR for microwave-assisted treatment. The results showed reduction of extraction time and energy consumption for microwave-assisted treatment leading to cost-effective technology for the extraction of polyphenol compounds. Furthermore, the results hereby compiled allow for the tailor-made extraction of specific high-value compounds from a renewable biomass as vine pruning residue.Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2019 unitBioTecNorte operation(NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do NorteInternational Cooperation Program CNPq/CSFinfo:eu-repo/semantics/publishedVersio