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The paper is focused on measurements of electric and thermal properties of alkali-activated aluminosilicates (AAAs) with a carbon nanotube (CNT) admixture. Such composites, fabricated from blast-furnace slag, quartz sand, water glass as an alkali activator, a small amount of electrically conductive CNT admixture and water exhibit better electric and thermal properties than the reference material without the CNT. Such an enhancement opens new practical applications, such as designing snow-melting, de-icing or self-sensing systems that do not need any external sensors to detect the current condition of the building's materials. Moreover, the economic aspect is more favourable in the case of AAA than that of Portland cement-based materials. The DC (direct current) electric properties are determined experimentally from the current-voltage (I-V) characteristics, the dielectric properties by means of impedance spectroscopy. Dielectric measurements allow us to determine the contribution of the individual components to the conductivity of the composite. The electric and thermal conductivities in the transverse direction were 16.16 μS/m and 0.907 W.m-1K-1 for 0 % of CNT and 34.46 μS/m and 1.298 W.m-1K-1 for 0.4 % of CNT, respectively

This paper deals with the relationship between grain yield and grain losses during harvest. Measurements were carried out on a combine harvester with axial harvesting device allowing various adjustments to combine harvester parameter settings, such as rotor speed, gap between separator and rotor, fan speed, holes of the upper and lower sieves. Values of harvest losses in combine harvester with custom settings for the given crops were compared with values of losses obtained by a harvester with manufacturer’s recommended settings. This paper observes the losses in grains of spring barley and winter wheat crops. All the measurements made showed lower grain losses when the combine harvester settings were customized. In general, custom settings provided quantitative losses lower by 0.198% than settings recommended by manufacturer.

The paper aims to introduce the distribution, history and the basic physical principles hydrostatic levelling. The principle of this method is based on known law of connected vessels filled with fluid. Well known equipment is surface water level, the height of the surface is deducted on millimetre scale. There are currently used devices that allow deducting with accuracy of 0.01 mm.

Particulate air pollution in cities is caused by a variety of sources. One of the less-studied contributors is wind-induced particle resuspension. As the wind speed increases, particles are removed from surfaces. These particles cause an increase in the total concentration in the air. It is known that particles of 10-2.5 μm in size can be resuspended (PM10-2,5). Modern emission monitoring in cities also allows the monitoring of fine particles of 10, 2.5 and 1 μm in size. The size fractions can then be sorted into PM10-2,5, PM2,5-1 and PM1. When breathed in, particles of different sizes cause various serious health risks. This paper focuses on the identification of the resuspension process of different particle size fractions by a data processing method. Data measured by automatic emission monitoring are used. It is confirmed that the concentration increase can be dominated by the fraction PM10-2,5. However, a concentration increase of fractions PM2,5-1 and PM1 is also evident with increasing wind speed. Although the increase in the PM1 fraction is smaller than PM10-2,5, it is more severe due to the respiratory deposition dose. The resuspension of particles of different fractions has different behaviours during the year. PM10-2,5 particles are dominantly resuspended in the summer months. In winter, on the other hand, the proportion of PM2.5-1 and PM1 particles increases, which may be related to the heating season

We calibrate Heston stochastic volatility model to real market data using several optimization techniques. We compare both global and local optimizers for different weights showing remarkable differences even for data (DAX options) from two consecutive days. We provide a novel calibration procedure that incorporates the usage of approximation formula and outperforms significantly other existing calibration methods.

This article concerns the way bee products are perceived by customers. It is mainly focused on honey, which is considered the main output product of beekeeping. Beekeeping is a very popular activity in the Czech Republic. Based on current data there are over 48 thousand people engaged in beekeeping in the Czech Republic. Hand in hand with the increasing number of beekeepers the popularity of bee products - especially honey - among Czech consumers is also growing. Recently, the consumption of honey in the Czech Republic has been slightly increasing. A big problem today is that honey sold in Czech supermarkets is frequently falsified. At the same time, it is increasingly popular to buy honey directly from beekeepers. The aim of this research was to describe the situation about the honey market in the Czech Republic, and also to examine the relationship between consumers on the one hand, and honey/beekeepers on the other. We have also considered customer's trust in organic honey and honey sold in supermarket chains. Results show that consumers view bee products as generally healthy and prefer to buy bee products from a beekeeper because of greater convenience as locally sourced honey is perceived to be of higher quality. The majority of consumers agree with paying a higher price for a product of higher quality. The article confirmed the hypothesis that most people think that bee products sold by a beekeeper are healthier than those bought at ordinary shops.

The article deals with the issue of dispersion and spreading of pollutants in small municipalities. The main attention is paid to the spreading of pollutants from line sources, i.e. roads in this case. Numerical modelling for selected localities, complemented with local measurements, is used for finding relations of dispersion of pollutants. The impact of a specific layout of urban areas on the dispersion of pollutants is monitored. Line sources, representing roads in numerical models, are described by the productions of pollutants and corresponding aerodynamic effects of moving vehicles on the ambient air. A large number of concentration maps are converted into a comprehensive database which allows a fast evaluation of similar situations without new immediate solutions or demanding SW tools.

The Ranque–Hilsch vortex tube represents a device for both cooling and heating applications. It uses compressed gas as drive medium. The temperature separation is affected by fluid flow behaviour inside the tube. It has not been sufficiently examined in detail yet and has the potential for further investigation. The aim of this paper is to compare results of numerical simulations of the vortex tube with obtained experimental data. The numerical study was using computational fluid dynamics (CFD), namely computational code STAR-CCM+. For the numerical study, a three-dimensional geometry model, and various turbulence physics models were used. For the validation of carried out calculations, an experimental device of the vortex tube of identical geometrical and operating conditions was created and tested. The numerical simulation results have been obtained for five different turbulence models, namely Standard k-ε, Realizable k-ε, Standard k-ω, SST k-ω and Reynolds stress model (RSM), were compared with experimental results. The most important evaluation factor was the temperature field in the vortex tube. All named models of turbulence were able to predict the general flow behaviour in the vortex tube with satisfactory precision. Standard k-ε turbulence model predicted temperature distribution in the best accordance with the obtained experimental data.

Fine particles generated from laboratory biomass combustion are discussed in this study. The approach combines the thermogravimetric analysis during thermal decomposition of beech wood sample with detailed monitoring of the size distribution of fine particles produced. Thermogravimetric analysis (TGA) allows monitoring the exact temperature influence of a small fuel sample (wood) according to the desired schedule. The cool aerosol stream leaving TGA enters a Scanning Mobility Particle Sizer (SMPS) where the particle size fractions are separated. The monodisperse aerosol is counted by the condensation particle counter (CPC). The parametrical study was carried out to assess the influence of composition, size and surface of the wood sample on the production and size distribution of ultrafine particles

Electronic cigarettes (e-cigarettes) have become very popular recently because they are marketed as a healthier alternative to tobacco smoking and as a useful tool to smoking cessation. E-cigarettes use a heating element to create an aerosol from a solution usually consisting of propylene glycol, glycerol, and nicotine. Despite the wide spread of e-cigarettes, information about aerosol size distributions is rather sparse. This can be caused by the relative newness of e-cigarettes and by the difficulty of the measurements, in which one has to deal with high concentration aerosol containing volatile compounds. Therefore, we assembled an experimental setup for size measurements of e-cigarette aerosol in conjunction with a piston based machine in order to simulate a typical puff. A TSI scanning mobility particle sizer 3936 was employed to provide information about particle concentrations and sizes. An e-cigarette commercially available on the Czech Republic market was tested and the results were compared with a conventional tobacco cigarette. The particles emitted from the e-cigarette were smaller than those of the conventional cigarette having a CMD of 150 and 200 nm. However, the total concentration of particles from e-cigarette was higher.

This paper presents results of a studied heat transfer coefficient at the surface of a sprinkled tube bundle where boiling occurs. Research in the area of sprinkled exchangers can be divided into two major parts. The first part is research on heat transfer and determination of the heat transfer coefficient at sprinkled tube bundles for various liquids, whether boiling or not. The second part is testing of sprinkle modes for various tube diameters, tube pitches and tube materials and determination of individual modes’ interface. All results published so far for water as the falling film liquid apply to one to three tubes for which the mentioned relations studied are determined in rigid laboratory conditions defined strictly in advance. The sprinkled tubes were not viewed from the operational perspective where there are more tubes and various modes may occur in different parts with various heat transfer values. The article focuses on these processes. The tube is located in a low-pressure chamber where vacuum is generated using an exhauster via ejector. The tube consists of smooth copper tubes of 12 mm diameter placed horizontally one above another.

Water flowing on a sprinkled tube bundle forms three basic modes: It is the Droplet mode (liquid drips from one tube to another), the Jet mode (with an increasing flow rate droplets merge into a column) and the Membrane (Sheet) mode (with further increasing of falling film liquid flow rate columns merge and create sheets between the tubes. With sufficient flow rate sheets merge at this state and the tube bundle is completely covered by a thin liquid film). There are several factors influencing the individual mode types as well as heat transfer. Beside the above mentioned falling film liquid flow rate they are for instance tube diameters, tube pitches in a tube bundle or a physical condition of a falling film liquid. This paper presents a summary of data measured at atmospheric pressure at a tube bundle consisting of copper tubes of 12 milimeters diameter and of the studied tube length one meter. The tubes are positioned horizontally one above another with the tested pitches of 15, 20, 25 and 30 mm and there is a distribution tube placed above them with water flowing out. The thermal gradient of 15–40 has been tested with all pitches where the falling film liquid’s temperature at the inlet of the distribution tube was 15 °C. The liquid was heated during the flow through the exchanger and the temperature of the sprinkled (heater) liquid at the inlet of the exchanger with a constant flow rate about 7.2 litres per minute was 40 °C. The tested flow of the falling film liquid ranged from 1.0 to 13.0 litres per minute. Sequences of 180 exposures have been recorded in partial flow rate stages by thermographic camera with record frequency of 30 Hz which were consequently assessed using the Matlab programme. This paper presents results achieved at the above mentioned pitches and at three types of tube bundle surfaces.

This paper presents a procedure for experimental determining the local heat transfer coefficient in the rotor-stator cavity. As an operating medium is used a hot air with various mass flow rate and rotating speed of the cavity wall. The surface temperature and heat flux distribution takes into account the change of material properties as a function of thermal distribution.

The paper focuses on the influence of sprinkled tube surface on distribution of temperature fields, i.e. the heat transfer coefficient on the tubes surface. Two types of tubes have been tested, a smooth one and a sandblasted one in particular. A tube bundle comprises of thirteen copper tubes divided into two rows and it is located in a low pressure chamber where vacuum is generated using an exhauster via ejector. The liquid tested was water at an absolute pressure in a chamber in between 97 kPa up to 10 kPa and a thermal gradient 55 to 30 °C. The flow of the falling film liquid ranged between zero and 17 litres per minute.

The paper presents research on the heat transfer at sprinkled tube bundles situated in a test chamber at atmospheric pressure and low-pressure. Dynamic effects of physical quantities influencing the heat transfer coefficient during boiling are examined experimentally. Experimental results were achieved by means of balance measuring using thermocouple probes and by analysis of thermal diagrams created during operation periods.

The adiabatic sorption is very interesting phenomenon that occurs when vapor of refrigerant is in contact with unsaturated liquid absorbent-refrigerant mixture and exchange of heat is forbid between the system and an environment. This contribution introduces new auxiliary lines that enable correct position determination of the adiabatic sorption process in the p-T-x diagram of ammoniawater system. The presented auxiliary lines were obtained from common functions for fast calculation of water-ammonia system properties. Absorption cycles designers often utilize p-t-x diagrams of working mixtures for first suggestion of new absorption cycles. The p-t-x diagrams enable fast correct determination of saturate states of liquid (and gaseous) mixtures of refrigerants and absorbents. The working mixture isn’t only at saturated state during a real working cycle. If we know pressure and temperature of an unsaturated mixture, exact position determination is possible in the p-t-x diagrams too.

Abstract Background Older age, as a factor we cannot affect, is consistently one of the main negative prognostic values in patients with acute myocardial infarction. One of the most powerful factors that improves outcomes in patients with acute coronary syndromes is the revascularization preferably performed by percutaneous coronary intervention. No data is currently available for the role of age in large groups of consecutive patients with PCI as the nearly sole method of revascularization in AMI patients. The aim of this study was to analyze age-related differences in treatment strategies, results of PCI procedures and both in-hospital and long-term outcomes of consecutive patients with acute myocardial infarction. Methods Retrospective multicenter analysis of 3814 consecutive acute myocardial infarction patients divided into two groups according to age (1800 patients ≤ 65 years and 2014 patients > 65 years). Significantly more older patients had a history of diabetes mellitus and previous myocardial infarctions. Results The older population had a significantly lower rate of coronary angiographies (1726; 95.9% vs. 1860; 92.4%, p Conclusions In a consecutive AMI population, the older group (>65 years) was associated with a less pronounced impact of risk factors on long-term outcome. To ascertain the coronary anatomy by coronary angiography and proceed to PCI if suitable regardless of age is crucial in all patients, though the primary success rate of PCI in the older age is lower. Age, when viewed as a risk factor, was a dominant discriminating factor in all patients.