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Abstract

The research was focused on the heating capacity of developed, isolated from water penetration, knitted textile heating element with incorporated conductive silver (Ag)- plated yarns, which can be used in manufacturing heating textile products intended for recreation, sports, or health care for elderly. The aim of the investigation was to obtain an appropriate temperature on a human skin, generated by the textile heating element surface at a lower voltage depending on a variety of wearing conditions indoor. Depending on the supplied voltage to the heating element, an incoming electric energy can be converted into different heat. Therefore, the electrical and achieved temperature parameters of heating elements are very important by selecting and adapting required power source devices and by setting the logical parameters of programmable controllers. The heating–cooling dynamic process of developed textile heating element was investigated at different simulated wearing conditions on a standard sweating hot plate and on a human skin at applied voltages of 3V and 5V. It was discovered that a voltage of 5 V is too big for textile heating elements, because the reached steady state temperature increases to approximately 39–40°C, which is too hot for contact with the human skin. The voltage of 3 V is the most suitable to work properly and continuously, i.e., to switch on when the adjusted temperature is too low and to turn off when the necessary temperature is reached. Based on the values of reached steady-state heating temperature, the influence of the applied voltage, ambient air flow velocity, and heating efficiency, depending on various layering of clothes, was determined. Recorded temperatures on the external surface of the heating element provided the possibility to assess its heat loss outgoing into the environment. It was suggested that heat loss can be reduced by increasing thermal insulation properties of the outer layer of the heating element or using layered clothing. On the basis of the resulted heating characteristics, recommended parameters of power source necessary for wearable textile heating element were defined.

Abstract

We study the boundary layer characteristics of heat and mass transfer flow past a vertical wedge in the presence of thermal radiation. The surface temperature and the species concentration are assumed to be oscillating in the magnitude but not in the direction of oncoming flow velocity. The governing equations have been solved by two distinct methods, namely, the straightforward finite difference method for the entire frequency range, and the series solution for the low frequency range and the asymptotic series expansion method for the high frequency range. Numerical solutions have been presented in terms of the amplitudes and phase angles of the skin friction, the rate of heat transfer and the mass transfer with the variations of Richardson’s number, the Prandtl number, the conduction–radiation parameter, the surface temperature parameter and the Schmidt number. Furthermore, the effects of these parameters are examined in terms of the transient skin friction, heat transfer and mass transfer.

Abstract

Due to the introduced political instruments, as well as the increase in awareness and standard of living, mechanical ventilation is becoming more and more popular in Poland. The growing market and standards force the manufacturers of air handling units to constantly improve the quality of their products. In order to verify the operation of these devices, it is necessary in a specially adapted for this object called the climate chamber. Due to the strict regulations regarding the working conditions of the said facilities, it is necessary to apply the processes of advanced control systems in the process of regulation. These processes are aimed at establishing stable parameters of air supplied to the tested objects, ventilation and air-conditioning units such as: temperature, humidity, flux. Due to the need for precise control and operation of the installation in industrial conditions, it was decided to use the PID controller. The article deals with the optimization of the heating and cooling system, because the temperature parameter was a problematic element in the proper operation of the climate chamber. Both the heating and cooling systems have been described and executive elements have been emphasized, thanks to which it was possible to control the flow of circulating factors. The procedure of selection and implementation of the regulator's settings and its influence on the operation of the climate chamber was also analyzed.

Abstract

An analysis is presented to investigate the unsteady magnetohydrodynamic (MHD) mixed convection boundary-layer flow of a micropolar fluid over a vertical wedge in the presence of thermal radiation and heat generation or absorption. The free-stream velocity and surface temperature are assumed to be oscillating in magnitude but not in the direction of the oncoming flow velocity. The governing equations have been solved by two distinct methods, namely, the finite difference method for the entire frequency range, and the series solution for low frequency range and the asymptotic series expansion method for the high frequency range. Numerical solutions provide a good agreement with the series solutions. The amplitudes of skin friction and couple stress coefficients are found to be strongly dependent on the Richardson number and the vortex viscosity parameter. The Prandtl number, the conduction-radiation parameter, the surface temperature parameter and the pressure gradient parameter significantly affect the amplitudes of skin friction, couple stress and surface heat transfer rates. However, the amplitudes of skin friction coefficient are considerably affected by the magnetic field parameter, whereas the amplitudes of heat transfer rate are appreciably changed with the heat generation or absorption parameter. In addition, results are presented for the transient skin friction, couple stress and heat transfer rate with the variations of the Richardson number, the vortex viscosity parameter, the pressure gradient parameter and the magnetic field parameter.

Abstract

Titanium oxide (TiO2) films have been synthesized on quartz, silicon and textured silicon substrates by chemical ultrasonic spray deposition. The textured silicon substrate was carried out using Na2CO3 solution. The sample surface exhibits uniform pyramids with an average height of 5 µm. In this paper, particular attention is given to the TiO2 films prepared by spray ultrasonic system using Tetra iso-Propoxide Orthotitanate Titanium (TPOT) as a precursor. The solutions were sprayed onto substrates heated at various temperatures 350 - 550 °C. The properties of films as a function of temperature parameter were investigated using structural and optical analysis. According to XRD, FTIR and Micro-Raman spectroscopies, the anatase phase was found and exhibits nanograins of 9 to 15 nm in size. The indirect and direct bad gap were found to increase by increasing substrate temperature due to the decreasing of nanograins size and were estimated to be around 3.28 and 3.38 eV. A transmittance higher than 80% was found. This paper reports on anti-reflection coating application of TiO2 layers due to its good transparency and appropriate refractive index varies between 2.19 - 2.40 at λ = 632.8 nm as a function of temperature determined by UVVisNIR spectrophotometer and Ellipsometry. To achieve optimum anti-reflection characteristics different anti-reflection designs were experimentally examined with polished and textured substrates. The average reflectance of the polished silicon used in this study is 39%, with TiO2 it decreases to 9%. The textured surface reduces the average reflectance of silicon to be around 14% and it decreases dramatically to 5% after deposition of a single layer of TiO2 as an anti-reflection coating. The gain in density of the short-circuit photocurrent assigned to the reduction of reflection losses up to 44% and 58% were predicted with TiO2 single-coating in polished and textured silicon substrates respectively.

temperature parameters of wooden lightweight external walls. In: STRUCTURA stavební trendy 2013: ekologie, energetika, bezpečnost, udržitelnost : 3. ročník mezinárodní stavební konference, Ostrava 7. – 8. 11.2013, sborník prací ke konferenci. Ostrava VŠB - Technická univerzita, 2013, ISBN 978-80-248-3236-4. [4] ŠUŠTIAKOVÁ, M. – ĎURICA, P. – PONECHAL, R. – CANGÁR, M.: Comparison of experimental and computational characteristics of light perimeter walls of wooden buildings. In: 6th International Conference on Contemporary Problems of Architecture and Construction: 24 th – 27

. Grishko, N. V. Goryachev, I. I. Kochegarov, and M. P. Kalaev, “Mathematical Models of the System of Measurement and Analysis of Temperature Parameters of Radio Electronic Modules,” in 2016 13th International Scientific-Technical Conference on Actual Problems of Electronics Instrument Engineering (APEIE) , Novosibirsk, Russia, October 3–6, 2016, vol. 2, pp. 112–115, https://doi.org/10.1109/apeie.2016.7806424 [18] E. Y. Maksimov, N. K. Yurkov, and A. N. Yakimov, “A Finite-Element Model of the Thermal Influences on a Microstrip Antenna,” Measurement Techniques , vol. 54

Test Symposium , EWDTS, Oct. 2016. https://doi.org/10.1109/EWDTS.2016.7807740 [5] A. K. Grishko, N. V. Goryachev, I. I. Kochegarov, and M. P. Kalaev, “Mathematical models of the system of measurement and analysis of temperature parameters of radio electronic modules,” in 2016 13th International Scientific-Technical Conference on Actual Problems of Electronics Instrument Engineering (APEIE) , Novosibirsk, Russia, October 03–06, 2016, vol. 2, pp. 112–115. https://doi.org/10.1109/APEIE.2016.7806424 [6] E. Y. Maksimov, N. K. Yurkov, and A. N. Yakimov, “A finite

, “Contactless three-component measurement of mirror antenna vibrations, “ Proceedings 2016 International Siberian Conference on Control and Communications, SIBCON, May 2016. https://doi.org/10.1109/SIBCON.2016.7491673 [6] A. K. Grishko, N. V. Goryachev, I. I. Kochegarov, and M. P. Kalaev, “Mathematical models of the system of measurement and analysis of temperature parameters of radio electronic modules,” in 2016 13th International Scientific-Technical Conference on Actual Problems of Electronics Instrument Engineering (APEIE) , Novosibirsk, Russia, October 03–06, 2016

.F., Mayer, D.G. (1988). Representing cumulative germination. 2. The use of the Weibull function and other empirically derived curves. Annals of Botany, 61, 127-138. Carberry, P.S., Campbell, L.C. (1989). Temperature parameters useful for modeling the germination and emergence of pearl millet. Crop Science, 29, 220-223. Carberry, P.S., Muchow, R.C., McCown, R.L. (1993). A simulation model of kenaf for assisting fibre industry planning in northern Australia. IV. Analysis of climatic risk. Australian Journal of Agricultural Research , 44, 713-730. Cieśla A