Peculiarities of High-Energy Induction Heating during Surface Hardening in Hybrid Processing Conditions

This paper presents the results obtained when combining mechanical and surface-thermal operations, using the same process equipment. The paper also demonstrates the possibility of implementing high-energy heating with high-frequency currents, and proposes using an integral temperature–time characteristic as the main parameter to specify surface quenching modes. The numerical values of the integral temperature–time characteristic are to be related to the processing modes and the depth of hardening. The experiments confirmed that an increase in the capacity will be commensurate with an increase in power consumption when a volumetric heating scheme (with a hardening depth of 0.5 mm) is realized. However, during the realization of a volumetric heating scheme, when the 0.7 mm depth of the hardened layer is at the boundary of the “hot” depth of the current penetration into the metal (the beginning of the intermediate heating scheme), the increase in the processing capacity will be higher than that in power consumption.

Research long-term fluctuations in winter temperatures. Methods for analyzing the intensities and synchronicities of fluctuations in fuel consumption

The article deals with the problem of assessing the deviations of the meteorological characteristics of the heating season. The usual method of calculating the relative deviations of indicators from the arithmetic mean is not suitable. A requirement is imposed on the “new” averages and estimates of deviations of meteorological characteristics, which follows from their properties: the duration multiplied by the average daily temperature difference for the heating period should be equal to the integral temperature difference. The application of this property to the means and to the very estimates of the deviations of meteorological characteristics makes it difficult to determine the latter. A method is being developed to determine the intensities of fluctuations in the meteorological characteristics of the heating season. Intensities show how much, on average, the duration, average daily and integral temperature differences for the heating period can deviate from the average expected level. A technique is being developed for reflecting synchronous and asynchronous fluctuations in deviations of meteorological characteristics, and the contributions of these fluctuations are determined.

Multy-year oscillations investigation of winter temperatures Prediction of integrated temperature difference during the heating period

To estimate possible deviations in fuel consumption for heating based on meteorological observations of previous years, the integrated temperature difference inside and outside the building during the heating season is used. When the heating period is divided into two subperiods relative to the considered date (for example, before and after December 1), the accumulated and residual integral temperature differences are obtained. The assumption about the presence of a statistical relationship between the accumulated and residual integral temperature difference is confirmed. A model for predicting the probability of the expected values of the integral temperature difference for the upcoming heating period is developed. The model is focused on obtaining matrices of conditional probabilities of observations from intervals of dividing the accumulated integral temperature differences into intervals of residual integral temperature differences.

Investigation of the effective parameters of scuffing failure in gears

This study investigates the effective parameters of scuffing failure in gears using the integral temperature method. For this aim, the mass temperature, integral temperature and scuffing safety factor are calculated for a given parameters. Then, integral temperatures are simulated based on various geometrical, operational and lubrication parameters. Obtained results are presented graphically. The obtained results show that increasing the module mn results in a decrease in the integral temperature ϑint. Similarly, increasing the pinion teeth number zp results in a decrease in the integral temperature ϑint. Increasing the module and tooth number positively affects the scuffing failure in gears. In contrast, increasing the transmitted torque MT1T results in an increase in the integral temperature ϑint. Similarly, increasing the pinion speed np increases the mass temperature ϑM, and increasing the lubricant (oil) ϑÖ temperature increases the integral temperature ϑint. Increasing the transmitted torque, lubricant temperature and the pinion speed negatively affects the scuffing failure in gears. Finally, increasing the nominal kinematic viscosity v40 decreases the integral temperature ϑint. Increasing the nominal kinematic viscosity positively affects the scuffing failure in gears. By considering the effective parameters of scuffing failure such as geometrical, operational and lubrication, one can design and manufacture the desired gears without scuffing failure.

Improving the accuracy of the time and frequency signal transmission over coaxial cable

This paper assesses the effect of wide temperature differences of cable segments on the stability of the transmitted frequency. Paper presents a method for determining the integral temperature of a long cable, as well as a method for compensating the introduced instability of the transmitted frequency. A method for stabilizing the integral temperature of a long coaxial cable using a proportional-integral-differentiating algorithm (PID) algorithm and a distributed heater is also proposed.

Design and development of polymerase chain reaction thermal cycler using proportional-integral temperature controller

A thermal cycler is used to amplify segments of DNA using the polymerase chain reaction (PCR). It is an instrument that requires precise temperature control and rapid temperature changes for certain experimental protocols. However, the commercial thermal cyclers are still bulky, expensive and limited for laboratory use only. As such it is difficult for on-site molecular screening and diagnostics. In this work, a portable and low cost thermal cycler was designed and developed. The thermal cycler block was designed to fit six microcentrifuge tubes. A Proportional-Integral temperature controller was used to control the thermal cycler block temperature. The results showed that the maximum temperature ramp rate of the developed thermal cycler was 5.5 °C/s. The proportional gain (Kp) and integral gain (Ki) of the PI controller were 15 A/V and 1.8 A/Vs respectively. Finally, the developed thermal cycler successfully amplified six DNA samples at the expected molecular weight of 150 base pair. It has been validated using the Eppendorf Mastercycler nexus gradient system and gel electrophoresis analysis

TWO METHODS FOR REMOTE ESTIMATION OF COMPLETE URBAN SURFACE TEMPERATURE

Complete urban surface temperature (<i>T</i>_C) is a key parameter for evaluating the energy exchange between the urban surface and atmosphere. At the present stage, the estimation of <i>T</i>_C still needs detailed 3D structure information of the urban surface, however, it is often difficult to obtain the geometric structure and composition of the corresponding temperature of urban surface, so that there is still lack of concise and efficient method for estimating the <i>T</i>_C by remote sensing. Based on the four typical urban surface scale models, combined with the Envi-met model, thermal radiant directionality forward modeling and kernel model, we analyzed a complete day and night cycle hourly component temperature and radiation temperature in each direction of two seasons of summer and winter, and calculated hemispherical integral temperature and <i>T</i>_C. The conclusion is obtained by examining the relationship of directional radiation temperature, hemispherical integral temperature and <i>T</i>_C: (1) There is an optimal angle of radiation temperature approaching the <i>T</i>_C in a single observation direction when viewing zenith angle is 45&amp;ndash;60°, the viewing azimuth near the vertical surface of the sun main plane, the average absolute difference is about 1.1&amp;thinsp;K in the daytime. (2) There are several (3&amp;ndash;5 times) directional temperatures of different view angle, under the situation of using the thermal radiation directionality kernel model can more accurately calculate the hemispherical integral temperature close to <i>T</i>_C, the mean absolute error is about 1.0&amp;thinsp;K in the daytime. This study proposed simple and effective strategies for estimating <i>T</i>_C by remote sensing, which are expected to improve the quantitative level of remote sensing of urban thermal environment.

INVESTIGATION OF THE INFLUENCE OF THE TEMPERATURE LEVEL ON THE BILATERAL MEAT FRYING PROCESS

The elaboration and introduction of the new high-energetic and resource effective equipment in the activity of food industrial enterprises, including restaurant economy is an urgent scientific problem. The most important role at that is played by the unit energetic consumption of energetic processes, which decrease allows to receive an economic effect. The rise of the energetic effectiveness of technological processes of fried meat products manufacturing is possible at the expanse of combining traditional and non-traditional (physical and electrophysical) processing methods. The use of combined thermal processing methods allows to raise the effectiveness of heat conduction from heating environments to a product. The aim of the research was the determination of the frying surfaces temperature at the bilateral heat supply for a value of the mean integral temperature pressure and frying process duration, ready product output and unit energy consumption. The change of the initial temperature level of the frying process has an essential influence on the mean integral temperature pressure between a frying surface and product surface layer. The temperature decrease of frying surfaces from 423 К to 393 К leads to the decrease of the mean integral temperature pressure between a frying surface temperature and product surface one by 4 К by the nonlinear law, and allows to raise the coefficient of heat conduction through steam layers. It was proved, that the bilateral frying of natural products of meat at the surfaces temperature 393 К allows to decrease the process duration by 6 s, to raise the ready product output by 3,3% and to decrease the unit electric energy consumption by 0,023 kW·hour/kg comparing with the bilateral frying at the surfaces temperature 423 К.