Papers by Keyword: Thermocouple

Abstract: The work discusses the problem of development of a heat-protective coating for objects of various purposes which are subjected to the external high-temperature impact. As a solution of the problem the application of heat-absorbing components providing the thermal barrier effect conducing to refraction of heat flows directed to heating of the protected object in the recipe of a heat-protective coating is presented. Temperature conditions of the protected object are provided due to the endothermic reaction which passes in the heat-protective layer by reaching the temperature of the selected component decomposition. Besides, the temperature of the heat absorption reaction has to be lower than the lesion temperature of the protected object.

Abstract: In this paper, the authors present the influence of cutting parameters, depth of cut, rotational speed and speed feed on the process temperature for milling of three types of aluminum alloys. In order to measure the temperature, an adequate experimental setup was used. This experimental setup consists in a noncontact infrared thermometer.

Abstract: The main purpose of this paper is to analyze the temperature in turning process of a titanium bar, both with noncontact infrared thermometer and thermocouple. In order to have a comparative appreciation of the difference between the temperature measured with contact and noncontact methods, the determinations are graphically represent separately and on the same figure.

Abstract: Nicrosil-nisil (NiCrSi-NiSi) thermocouples (Type N) have a high thermal EMF stability, radiation resistance, resistance to oxidation of the thermocouple wires and can be used as a universal means of measuring temperatures up to 1300 °C. However, when the traditional metallurgical method is used for the production of rod and wire materials of nicrosil and nisil from ingots of metals, it is difficult to ensure the homogeneity of the ingots and materials of the thermocouple. It is known that powder metallurgy methods can provide a greater homogeneity of the material compared to casting technology. The aim of this work was to study the possibility of using powder technology for the fabrication of rods of nicrosil and nisil thermocouple materials by extrusion and sintering of powders of source metals. Reduction in size and mixing of the raw powder components in a planetary ball mill was investigated. The regularities of pressing the prepared mixtures and microstructure of materials sintered from them were determined. Samples of nicrosil and nisil thermocouple materials in the form of cylindrical rods with a diameter of about 5 mm and a length of 200 mm with an uniform microstructure were also fabricated by extrusion of prepared mixtures followed by sintering. Experimentally determined specific differential thermal EMF of the thermocouple made from the sintered rods coincided with the theoretical value.

Abstract: This work presents a photolithographic rapid prototyping process for producing thin films ("Rapid Phototyping"). This process allows a quick and cost-effective generation of scalable thermopile microstructures using commercial equipment and materials. Structural widths of 100x250μm can be produced reproducible in a lift-off process with an accuracy of 5 microns vertically and 30 microns horizontally.

Abstract: Thermal errors cause serious dimensional errors to a workpiece in precision machining. A feed drive system generates more heat through friction at contact areas, such as the Linear encoder and the guide, thereby causing thermal expansion which affects machining accuracy. Therefore, the thermal deformation of a Linear encoder is one of the most important objects to consider for high-accuracy machine tools. This paper analyzes the increase of the temperature and the thermal deformation of a Linear encoder feed drive system. During temperature variation is measured by using thermocouples , meanwhile, the thermal error of the guide is measured by a laser interferometer. A thermal error model is proposed in this study by using back propagation neural network (BPN). An experiment is carried out to verify the thermal error of the guide under different feed rates and environmental temperature.

Abstract: This work examined improvements in cutting efficiency obtained during the slicing of sapphire workpieces when adding CeO₂ to the cutting fluid. Various machining parameters, including the cutting temperature, machining surface tolerance, surface quality and tool wear, were assessed. It was confirmed that both the cutting temperature and the machining surface tolerance are reduced by the presence of CeO₂ in the cutting fluid. Observations of the machined surfaces and the cutting tool also demonstrated that both brittle fracturing of the surface and loss of abrasive grains were suppressed following the addition of CeO₂. These results suggest that the cutting temperature likely affects the accuracy of the cutting process and that CeO₂ appears to improve cutting efficiency by reducing the workpiece temperature and by stabilizing the cutting process.

Abstract: A turning knife contacts a work piece during turning. Due to friction, heat is produced proportionally to the turning speed. The resulting temperature influences the quality of the machined surface and wear of the knife. Thus, new machine tools must be developed that minimize the production of unwanted heat. To accomplish this task, a new experimental knife was prepared with thermocouples both built into it and welded to its surface. The measurement process was supplemented by thermovision. Heat flux and surface temperatures were computed from subsurface data using a one-dimensional inverse relationship. The detailed temperature distribution on the surface of the turning knife was determined using a combination of these methods.

Abstract: Friction stir welding (FSW) of polymers is relatively a new concept among modern polymer joining techniques. This study demonstrates the applicability of FSW on 16mm thick nylon-6 plates at constant welding rate of 25mm/min and varying rotational speed between 300 to 1000RPM. A special designed tool was fabricated which has double shoulder and right-hand threaded pin profile. It has shown excellent results at relatively lower rotation speeds. Visual inspection and microstructural examination of cross sections showed that the cavities and tunnel defects appeared only at higher rotational speeds. A linear relationship was observed between temperature and rotation speed.

Abstract: Water is the main requirement for the agricultural crops. However, improper amount of water can disturb the plant growth. In modern agriculture, this issue can be tackled by providing the appropriate amount of water for the plant. One of the methods is automatic control system based on the type of physical variables, which indicates water needs for plants [1]. Physical variables that are frequently used as an indicator are temperature and soil moisture [2].The automatic control system can also be applied in agricultural areas that have less water availability. This is due to the automatic control system can help saving water and operating costs [3]. Efforts in building optimal and efficient automated control system can be easily done with complete access to information. One way to access the information control system is via wireless communications [3,4]. From some of these challenges an automatic control system will be built on the research for controlling irrigation in telemetry based on temperature and soil moisture.