Factors influencing walking distance to the preferred public transport stop in selected urban centres of Czechia

One of the ways of improving the attractiveness of public transport is to bring it closer to its potential users. A long walking distance from a stop is often one of the critical factors limiting its more frequent and extensive use. Studies dealing with the accessibility of transport networks usually work only with the closest stop. This article analyses the actual walking distance from the place of residence to the preferred stop. The survey used a questionnaire method and was conducted in two cities in the Czech Republic-Ostrava and Olomouc. Based on the results of the study, the average walking distance was assessed and the impact of demographic characteristics (gender, age, education, number of members in the household, economic activity, the presence of a child in the household, and car ownership), transport behavior (preferred mode of transportation, car convenience and opinions on public transport), and urban characteristics (prevailing housing type) on the walking distance were analyzed. The main findings prove a significant impact on walking distance by a number of these factors, but the preferred use of a car for commuting or unemployment does not significantly affect walking distance. Highlights for public administration, management and planning: The public transport stop reported as being closest to a respondent's residence was used by only 51% of all respondents in the survey. Another 20% of residents used the second closest stop, 11% the third stop. Travellers select the stop based on number of connections; seamless connection; the speed of connection; potential delays; equipment of stops and nearby areas; the comfort of the vehicle; avoiding overcrowded stop; other personal factors. The average walking distance to the preferred stop is 568 metres in Ostrava while only 439 metres in Olomouc. Significantly shorter distances refer to the female population in Ostrava, retired and unemployed. Assumption of the negative influence of the higher number of family members, higher salaries, car ownership and worse education (blue collar) was not proved.Web of Science131301

Study of mode transition in low pressure capacitive RF discharges in nitrogen

We have studied the mode transition in low pressure capacitive RF discharges in nitroge

SYNTHESIS OF CARBON NANOSTRUCTURES BY PLASMA ENHANCED CHEMICAL VAPOUR DEPOSITION AT ATMOSPHERIC PRESSURE

Carbon nanostructures present the leading field in nanotechnology research. A wide range of chemical and physical methods was used for carbon nanostructures synthesis including arc discharges, laser ablation and chemical vapour deposition. Plasma enhanced chemical vapour deposition (PECVD) with its application in modern microelectronics industry became soon target of research in carbon nanostructures synthesis. Selection of the ideal growth process depends on the application. Most of PECVD techniques work at low pressure requiring vacuum systems. However for industrial applications it would be desirable to work at atmospheric pressure. In this article carbon nanostructures synthesis by plasma discharges working at atmospheric pressure will be reviewed.Uhlíkové nanostruktury patří mezi vedoucí nanotechnologický výzkum. K syntéze uhlíkových nanostruktur lze použít širokou škálu chemických a fyzikálních metod jako například obloukové výboje, laserovou ablaci a CVD. PECVD se svých uplatněním v mikroelektronice se brzy stalo cílem výzkumu i v této oblasti. Výběr metod úzce souvisí s aplikací dané technologie. Ačkoli mnoho metod pracuje při nízkém tlaku, z hlediska aplikací by bylo vhodné použít metodou pracující za atmosférického tlaku. V této publikaci jsou shrnuty metody syntézy uhlíkových nanostruktur za atmosférického tlaku.Carbon nanostructures present the leading field in nanotechnology research. A wide range of chemical and physical methods was used for carbon nanostructures synthesis including arc discharges, laser ablation and chemical vapour deposition. Plasma enhanced chemical vapour deposition (PECVD) with its application in modern microelectronics industry became soon target of research in carbon nanostructures synthesis. Selection of the ideal growth process depends on the application. Most of PECVD techniques work at low pressure requiring vacuum systems. However for industrial applications it would be desirable to work at atmospheric pressure. In this article carbon nanostructures synthesis by plasma discharges working at atmospheric pressure will be reviewed

Molecular dynamics simulation of amine groups formation during plasma processing of polystyrene surfaces

Plasma treatment and plasma polymerization processes aiming to form amine groups on polystyrene surfaces were studied in-silico with molecular dynamics simulations. The simulations were compared with two experiments, (i) plasma treatment in N-2/H-2 bipolar pulsed discharge and (ii) plasma polymerization in cyclopropylamine/Ar radio frequency (RF) capacitively coupled discharge. To model favorable conditions for the incorporation of primary amine groups, we assumed the plasma treatment as the flux of NH2 radicals and energetic NH3 ions, and the plasma polymerization as the flux of cyclopropylamine molecules and energetic argon ions. It is shown in both the simulation and the experiment that the polystyrene treatment by the bipolar pulsed N-2/H-2 plasmas with an applied voltage of about +/- 1 kV formed a nitrogen-rich layer of a thickness of only a few nm. The simulations also showed that, as the NH3 incident energy increases, the ratio of primary amines to the total number of N atoms on the surface decreases. It is because the energetic ion bombardment brakes up N-H bonds of primary amines, which are mostly brought to the surface by NH2 radical adsorption. Our previous experimental work on the CPA plasma polymerization showed that increased RF power invested in the plasma leads to the deposition of films with lower nitrogen content. The MD simulations showed an increase of the nitrogen content with the Ar energy and a limited impact of the energetic bombardment on the retention of primary amines. Thus, the results highlighted the importance of the gas-phase processes on the nitrogen incorporation and primary amines retention in the plasma polymers. However, the higher energy flux towards the growing film clearly decreases amount of hydrogen and increases the polymer cross-linking

Liquid assisted plasma enhanced chemical vapour deposition with a non-thermal plasma jet at atmospheric pressure

The present study introduces a process for the synthesis of functional films onto substrates directly from the liquid phase. The reported method is based on the initialization of the synthesis by means of an atmospheric pressure plasma jet operating with argon above a thin liquid film of the starting material. The process is demonstrated by the formation of a thin, solid SiOx film from siloxane-based liquid precursors. Changes in the chemical properties of the precursor were studied in-situ during the polymerization process on the diamond crystal by using Fourier transform infrared spectroscopy The elemental composition of the SiOxCy films was analyzed by X-ray photoelectron spectroscopy (XPS). Furthermore, XPS was applied to study the effect of post-annealing processes on the composition of the films. The obtained deposits exhibit a low concentration of carbon groups. The amount of hydroxyl groups and interstitial water can be reduced significantly by post-process annealing of the films

Liquid assisted plasma enhanced chemical vapour deposition with a non-thermal plasma jet at atmospheric pressure

The present study introduces a process for the synthesis of functional films onto substrates directly from the liquid phase. The reported method is based on the initialization of the synthesis by means of an atmospheric pressure plasma jet operating with argon above a thin liquid film of the starting material. The process is demonstrated by the formation of a thin, solid SiOx film from siloxane-based liquid precursors. Changes in the chemical properties of the precursor were studied in-situ during the polymerization process on the diamond crystal by using Fourier transform infrared spectroscopy The elemental composition of the SiOxCy films was analyzed by X-ray photoelectron spectroscopy (XPS). Furthermore, XPS was applied to study the effect of post-annealing processes on the composition of the films. The obtained deposits exhibit a low concentration of carbon groups. The amount of hydroxyl groups and interstitial water can be reduced significantly by post-process annealing of the films

Fuzzy Logic in Traffic Engineering: A Review on Signal Control

Since 1965 when the fuzzy logic and fuzzy algebra were introduced by Lotfi Zadeh, the fuzzy theory successfully found its applications in the wide range of subject fields. This is mainly due to its ability to process various data, including vague or uncertain data, and provide results that are suitable for the decision making. This paper aims to provide comprehensive overview of literature on fuzzy control systems used for the management of the road traffic flow at road junctions. Several theoretical approaches from basic fuzzy models from the late 1970s to most recent combinations of real-time data with fuzzy inference system and genetic algorithms are mentioned and discussed throughout the paper. In most cases, fuzzy logic controllers provide considerable improvements in the efficiency of traffic junctions’ management

Measurement of Mechanical Properties of Composite Materials

The aim of the present work was the study of mechani- cal properties of MWCNT/PU. Four types of coatings were compared. Two different concentrations of MWCNTs com- mercially functionalized with COOH group were prepared and studied. These composites showed improved mechanical properties compared to PU, and the modified nanotubes proved to be much better fillers than the unmodified MWCNTs due to stronger filler-to-matrix attachment. Be- cause the modified nanotubes seem to be much more conven- ient composite filler, the first experiments with nanotube modification have been carried out. Modification using induc- tively coupled discharge in argon and oxygen mixture was successful and the mechanical properties of the composite were increased at the same level as in case of the commer- cially COOH functionalized MWCNT fillers.V práci byly studovány mechanické vlastnosti vrstev MWCNT/PU a porovnávány čtyry různé typy jejich nanášení. Práce byla zaměřená zejména na studium vlivu funkcionalizace uhlíkových nanotrubek v plazmatu na mechanické vlastnosti výsledného kompozitu. Rovněž se zabývalo modelováním viskoelastických a viskoplastických vlastností kompozitů MWCNT/PU

Atmospheric pressure microwave torch for synthesis of carbon nanotubes

The microwave (mw) plasma torch at atmospheric pressure has been studied for carbon nanotube (CNT) synthesis. The depositions were carried out on silicon substrates with 515 nm thin iron catalytic overlayers from the mixture of argon, hydrogen and methane. The optical emission spectroscopy of the torch showed the presence of C2 and CH radicals as well as carbon and hydrogen excited atoms. The vicinity of the substrate influenced the relative intensities and increased the emission of C2. For fixed mw power, the temperature of the substrate strongly depended on its position with respect to the nozzle electrode and on the gas mixture, particularly the amount of H2. The speed of the substrate heating during an early deposition phase had a significant effect on the CNT synthesis. An abrupt increase of the temperature at the beginning increased the efficiency of theCNTsynthesis. Areas of dense straight standing CNTs, 30 nm in average diameter, with approximately the same sized iron nanoparticles on their tops were found in accordance with the model of growth by plasma enhanced chemical vapour deposition. However, the deposit was not uniform and a place with only several nanometres thick CNTs grown on much larger iron particles was also found. Here, taking into account the gas temperature in the torch, 31003900 K, we can see similarities with the dissolutionprecipitation model of the CNT growth by high temperature methods, arc or laser ablation.Možnosti syntézy uhlíkových nanotrubek(CNTs) byly zkoumány v mikrovlnném výboji buzeném za atmosférického tlaku. Vrstvy byly deponovány na křemíkový substrát s vrstvou železa 5-15 nm sloužící jako katalyzátor ve směsi argonu,vodíku a metanu. Optická emisní spektroskopie výboje prokázala přítomnost radikálů C2 a CH a excitovaných stavů atomů uhlíku a vodíku. Přítomnost substrátu ovlivňovala intenzitu spekter a vedla k vzrůstu intenzity C2 pásu. Při konstantní hodnotě mikrovlnného výkonu byla teplota substrátu silně závislá na vzdálenosti substrátu vůči trysce a průtoku plynů, zejména vodíku. Rychlost zahřívání substrátu v počátení fázi depozice měla významný vliv na depozici CNTs. Prudké zvýšení teploty substrátu na začátku depozice mělo za důsledek zlepšení efektivity depozice CNTs. Na substrátech bylo možno nalézt oblasti hustě uspořádaných CNTs s průměrem okolo 30 nm, které byly na vrcholu ukončeny částicemi katalyzátoru o stejném průměru. Tento výsledek je v souladu s obecně příjmaným růstovým modelem CNTs při použití metody plasma enhanced chemical vapor deposition (PECVD). Deponována vrstva však není uniformní na celé ploše substrátu a byly nalezeny i místa s nanotrubkami, o průměru pouze několika nanometrů, rostoucími na částicích katalyzátoru s mnohem většími rozměry. Vezmeme-li v úvahu teplotu plynu ve výboji, 3100-3900 K, je možno v tomto výsledku spatřovat podobnost s modelem růstu CNTs "dissolution-precipitation" při vysokoteplotních metodách jako jsou obloukový výboj nebo laserová ablace