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Spinnability of PEO solutions with respect to their aging
Zelenková, Jana ; Peer, Petra ; Filip, Petr
Non - negligible portion of pol ymer commodity suffers from ageing that participates in sometimes significant changes of products attributes. Rheology represents a useful tool for a description of this process. The aim of this contribution is to evaluate possible ageing of PEO solution ( polyethylen e oxide ( M w =300,000 g/mol) dissolved in water at 10 wt.% concentration) based both on rheological characterization and on quality of electrospun fibres. Rheological measurements in steady shear and oscillatory modes were carried out using a rota tional rheometer MCR 501 (Anton Paar, Austria) equipped with the concentric cylinders geometry. The electrospinning measurements were executed with the help of a proposed laboratory device. The tip - to - collector distance attained 20 cm, applied voltage rang ed from 20 to 30 kV. The obtained electrospun fibres were analysed using a scanning electron microscope (VEGA 3, Tescan, Czech Republic). Both types of measurements were carried out in the period of several months during which the solution studied was plac ed in a dark and tempered box (25°C). The measurements indicate no ageing impact on rheological characteristics or quality of electrospun fibres. This guarantees more or less the identical quality of non - woven textiles prepared from PEO solutions regardles s of time period during which the solutions are deposited.
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Does oxidation make the organic aerosol coatings more hydrophilic? Insight from molecular dynamics study of oxidized surfactant monolayers
Roeselová, Martina ; Khabiri, Morteza ; Cwiklik, Lukasz
Organic compounds are ubiquitous in atmospheric aerosols. The morphology and structure of the organic phase affect the optical properties of the aerosols, their heterogeneous reactivity as well as their ability to nucleate cloud droplets and ice particles. It is commonly assumed that atmospheric oxidative ageing of the organic material, leading to the formation of polar groups such as carbonyl (=O), hydroxyl (-OH) and carboxylic acid (-COOH), will render the aerosol particle surfaces increasingly more hydrophilic, hence, able to take up more water. Field measurements have shown that a large fraction of the organic material found in aerosols are surface active compounds, such as fatty acids and lipids(Tervahattu, 2002 and 2005). An inverted micelle structure, with an aqueous core surrounded by an organic surfactant layer, has thus been proposed for aqueous aerosols, both marine and continental (Donaldson, 2006). While recent experiments suggest the existence of more complex structures, such as organic inclusions and surfactant lenses (Dennis-Smither, 2012), a monolayer (ML) of surface active organics on an aqueous subphase (the so called Langmuir monolayers) represents the basic model system used in laboratory studies aimed at elucidating the effect of oxidative processes on structural properties of organic coatings on aerosol particles. In our previous work, we used molecular dynamics computer simulations to study the structure and stability of oxidized phospholipid MLs (Khabiri, 2012). In this contribution, we employed the molecular dynamics simulation technique to investigate – with atomistic resolution – structural changes occuring in a fatty acid ML upon moderate degree of oxidation.
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Bayesovská klasifikace rastrových obrazů pomocí webové aplikace
Talich, M. ; Böhm, O. ; Soukup, Lubomír
Příspěvek představuje webovou aplikaci pro klasifikaci obrazů, vyvíjenou v rámci projektu MŠMT InGeoCalc. Aplikace umožňuje zobrazovat, prohlížet a klasifikovat obrazová data poskytovaná prostřednictvím WMS (Web Map Service) nebo klasické snímky (georeferencované i negeoreferencované). Lze kombinovat data z různých zdrojů, jednotlivé "vrstvy" je možné pro lepší názornost různě zprůhledňovat. Nad daty je možno nezávisle na zdroji provádět řízenou klasifikaci, založenou na bayesovském přístupu. Na výběr je několik základních algoritmů klasifikace s možností nastavení parametrů. Aplikace dále nabízí základní analytické nástroje - výpočet délek, ploch a obvodů na základě klasifikace či uživatelem definovaných polygonů, jednoduché statistické přehledy o klasifikaci (procentuální zastoupení tříd, podíl neklasifikovaných oblastí apod.). Výsledky klasifikace lze ukládat včetně údajů o georeferenci. Aplikace je postavena na běžně rozšířených technologiích a standardech, jediným požadavkem na provozování aplikace je moderní internetový prohlížeč zvládající práci s SVG a přístup k internetu. Jedním z uplatnění aplikace může být např. využití v lesnictví a zemědělství při klasifikaci leteckých měřických snímků. Aplikace je přístupná zdarma.
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Convexity in stochastic programming model with indicators of ecological stability
Houda, Michal
We develop an optimization model dealing with construction expenses that are prescribed as a result of the EIA (Environmental Impact Assessment) process. The process is an obligatory part of every large construction project and evaluates possible influences of the project to the environment, including population health, natural and other socio-economic aspects; the result of the process is a set of recommendation and arrangements the construction must meet. Our optimization model incorporates uncertainties in model parameters; we represent them through their probabilistic distribution. Furthermore, to overcome a problem with quantifying subjective utility function of ecological impacts, we measure them by so-called indicators of ecological stability. The resulting problem is stochastic programming problem formulated as (C)VaR model used traditionally in finance area. In our contribution we deal with convexity properties of this problem – these are especially important from the theoretical as well as from the computational point of view.
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Psychologická prevence nehod
PAPAJOVÁ, Hana
Tato diplomová práce se zabývá psychologickou prevencí pracovních úrazů. První kapitola se zabývá pracovními úrazy, konkrétněji postupem při pracovním úraze - jaké jsou povinnosti zaměstnavatele, ale také zaměstnance. Další podkapitolou je odpovědnost za škodu při pracovních úrazech, dále odškodnění pracovních úrazů jako je náhrada za ztrátu na výdělku, náhrada za bolest a ztížené společenské uplatnění, účelně vynaložené náklady spojené s léčením a náhrada za věcnou škodu. Druhá kapitola je zaměřena na bezpečnost práce. Nejprve se zabývá bezpečností a ochranou práce obecně, dále školením BOZP, souvisejícími základními dokumenty, OHSAS 18001 Certifikace systému managementu BOZP ? přínosy certifikace a ?Bezpečný podnik?. Poslední podkapitolou jsou orgány inspekce práce ? dodržování povinností daných právními předpisy, činnosti orgánů inspekce práce, náplň jejich činnosti a oprávnění inspektora práce. Třetí kapitolou je prevence pracovních úrazů. První podkapitolou jsou povinnosti zaměstnavatelů, další je psychická zátěž a její projevy,psychologie práce, dále bezpečnostní požadavky na stroje a zařízení, příklady příčin vzniku pracovních úrazů a konkrétněji zásady bezpečnosti práce v potravinářském průmyslu. To by bylo k teoretické části vše. V praktické části mé diplomové práce jsem zpracovávala nejprve kvantitativní výzkum. Požádala jsem celkem 9 výroben masných výrobků, jednalo se o malé i velké firmy z různých krajů České republiky, o vyplnění dotazníku, který jsem si sama sestavila tak, abych došla k závěru, splnila cíle práce a odpověděla na otázky, které jsem si na začátku práce stanovila. Dále jsem ve firmě, ve které jsem zjistila nejmenší úrazovost, provedla kvalitativní výzkum formou rozhovoru, abych získala podrobnější informace o jejich přístupu k dané problematice.
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Performance of Continuous Micro Photo Reactor – Comparison with Batch Process
Drhová, Magdalena ; Hejda, S. ; Křišťál, Jiří ; Klusoň, Petr
Utilization of the flow chemistry as well as microreactors belongs to the latest trends in chemical engineering. Continuous microreactors of various kinds can be found in the literature, for example the micromixers, micro packed beds, or micro photo reactors. In order to evaluate the benefits of microtechnology application for the given process, the performance of a particular microreactor needs to be compared with the conventional setup. This contribution presents the performance of a continuous micro photo reactor in comparison with a batch process. Two model reactions were selected: the catalyzed photooxidation of 4-chlorophenol (4-CP) and the singlet oxygen chemical quencher 9,10-dimethylanthracene (DMA) in dimethylformamide. The tests were carried out using advanced opto-chemical apparatus with a well-defined light filter corresponding to the absorption bands of the used photo catalysts.
Plný tet: SKMBT_C22012102414080 -  PDF
Plný text: content.csg - PDF
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Thin Film Composite Membrane for Effective Raw Biogas Upgrading to Pipeline Quality Methane
Kárászová, Magda ; Vejražka, Jiří ; Veselý, Václav ; Friess, K. ; Randová, A. ; Jansen, J. C. ; Izák, Pavel
In this contribution we propose a method to upgrade biogas to the same quality of fuel standard natural gas. The latter contains more than 95 vol. % of methane. Using traditional membranes, such concentration of methane in the retentate could only be achieved using a multistep process. A recently proposed method for raw biogas purification from impurities and carbon dioxide by condensing water on swollen thin film composite membranes was found to be highly effective. The hydrophilic reverse osmosis membrane promotes the formation of a very thin selective water layer under condensing conditions below the dew point of the raw biogas feed. The large difference in permeability of the impurities in raw biogas (carbon dioxide, hydrogen sulfide) and methane through the water layer enables upgrading of raw biogas to biomethane quality in a single stage. Contrary to the classical purification processes, the proposed method does not require any biogas pretreatment, which makes this approach economically attractive. It represents an innovative approach to production of biomethane from biogas.
Plný tet: SKMBT_C22012102413470 - PDF
Plný text: content.csg - PDF
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Process-Based Model of Mixed-Matrix Membrane
Čapek, P. ; Hejtmánek, Vladimír ; Veselý, M. ; Sysel, P. ; Kočiřík, Milan ; Brabec, Libor ; Zikánová, Arlette ; Bernauer, B. ; Fíla, V.
The focus of this contribution was on the formulation and verification of a process-based model of the mixed-matrix membrane that consisted of the polyimide matrix synthesized from the monomers 4,4’-(hexafluoroisopropylidene)diphtalic anhydride and 4,4’-oxydianiline, and silicalite-1. When a solution of a polyimide precursor in N,N-dimethylformamide was ready, silicalite-1 particles were dispersed in the solution and the dispersion was subsequently cast on a Teflon support plate. An initial mass ratio of silicalite-1 and polyimide was about 1:1. After solvent removal, the films were heated in subsequent steps up to 230°C for two hour. From a process-based model point of view, a key operation of the entire synthesis was slow sedimentation of silicalite particles in the viscous solution. Preliminary observation of 2D cuts through the solid membrane in a scanning electron microscope revealed that there were a lot of contacts among the silicalite particles. Therefore, a sequential (ballistic) deposition algorithm, well representing sedimentation in a low-energy environment, was used to create an off-lattice model of spatial distribution of the silicalite particles in the polyimide matrix.
Plný tet: SKMBT_C22012102413461 - PDF
Plný text: content.csg - PDF
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Changes in Ion Exchanger Catalysts after More than 10 Year Time-on-Stream
Jeřábek, Karel ; Hanková, Libuše ; Holub, Ladislav ; Slavík, H.
In this contribution will be reported results of examination of a series of industrial ion exchanger catalysts samples exposed to the environment of catalytic reactor in process of esterification of acrylic acid with methanol for more than 10 years. There was evaluated their acid capacity, swelling and using inverse steric exclusion chromatography (ISEC) also their morphology in water-swollen state. For comparison, similarly were evaluated also reference samples of the same but virgin ion exchangers.
Plný tet: SKMBT_C22012102413430 - PDF
Plný text: content.csg - PDF
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