Detection of invisible cracks in ceramic materials using by pre-trained deep convolutional neural network

Ceramic materials are an indispensable part of our lives. Today, ceramic materials are mainly used in construction and kitchenware production. The fact that some deformations cannot be seen with the naked eye in the ceramic industry leads to a loss of time in the detection of deformations in the products. Delays that may occur in the elimination of deformations and in the planning of the production process cause the products with deformation to be excessive, which adversely affects the quality. In this study, a deep learning model based on acoustic noise data and transfer learning techniques was designed to detect cracks in ceramic plates. In order to create a data set, noise curves were obtained by applying the same magnitude impact to the ceramic experiment plates by impact pendulum. For experimental application, ceramic plates with three invisible cracks and one undamaged ceramic plate were used. The deep learning model was trained and tested for crack detection in ceramic plates by the data set obtained from the noise graphs. As a result, 99.50% accuracy was achieved with the deep learning model based on acoustic noise.

Investigating the radiation-convective heat exchange of a metal-ceramic plate

The paper presents the experimental data on heat exchange during thermo-cyclic interaction of a flame jet with a thermal barrier ceramic coating. Cooling due to radiant heat transfer into the environment allows organizing heat exchange in such a way that when a flow of combustion products with a temperature of 1500 °C flows onto the sample, the temperature on the surface of the TBC does not exceed 1200 °C. The thickness of TGO after 1500 thermal cycles was 9.5 microns

Experimental studies of the thermal regime of the room when using heating ceramic panels

The article presents the results of experimental studies of the parameters of ceramic panels. Experimental measurements of air temperature in a room for which an electric ceramic panel is used as heating devices are given. The automatic system of monitoring of temperature in the room is described. During the experiments it was determined that the surface temperature of the ceramic plate of the heater is higher in the center and decreases when approaching the edges. It is proved that the use of constant surface temperature is acceptable in CFD modeling of a room with ceramic electric heaters. The profile of temperature distribution on height of the room at its heating by means of an electric ceramic heater is resulted in work. The air temperature is relatively evenly distributed over the height of the room. In this study, when entering the quasi-stationary mode, the air temperature in the height of the room varied in the range from 24 to 27˚C, which is slightly higher than the norm for the temperature in domestic premises. In order to save energy in this case it is necessary to reduce the service life of ceramic electric heaters. In the future it is necessary to develop a thermophysical numerical model and verify it with the help of the obtained experimental data. In addition, with the help of the model you can conduct research and determine the optimal location of ceramic electric heaters in the space of the room. Key words: radiation ceramic heater, experimental research, temperature monitoring.

Fabrication of Catalytic Converter with Different Materials and Comparison with Existing Materials in Addition to Analysis of Turbine Installed at the Exhaust of 4 Stroke SI Engine

Harmful pollutants (CO, NO, and unburnt hydrocarbons) coming out from the exhaust manifold of an engine must be converted into harmless gases by using catalytic converter. This field has seen vast research for increasing the conversion efficiency of pollutants by using different cheap metals. Nowadays, catalysts used in catalytic converter are noble metals, and they are also critical in the sense that they are not abundant on Earth. Platinum, palladium and rhodium are very expensive; hence, low-cost cars are not installed with catalytic converter, especially in third world countries. This research has been carried out to assess the catalytic activity of catalysts made from the salt/metal precursors, cerium sulphate tetra hydrate, manganese sulphate mono hydrate and copper sulphate penta hydrate that are not expensive and also less affected by the poison. Test sample catalysts were prepared through a coprecipitation method having different molar concentrations, and then tested for the conversion efficiency by applying the catalysts on ceramic plates by using flue gas analyzer. On the basis of the results, final catalysts were prepared and applied on a monolithic ceramic plate and then tested with regard to the resulting conversion rate of pollutants as compared to already installed catalytic converter. Moreover, turbine was installed in the exhaust passage to generate the power that would be utilized to run the electrical accessories of the engine. SOLIDWORKS were used for 3D CAD modeling and the flow analysis of turbine with radial inlet-axial outlet. In addition, ANSYS was used for stress-strain analysis.

Numerical Study of Heat Transfer and Optimum Design for Trench Laying Cables with Ceramic Plates

Trench laying cables are often used at inlet and outlet regions of a power distribution cabinet. In order to improve the heat transfer performance and extend service life of a trench laying cable, the heat transfer and cable ampacity of the trench laying cable with a ceramic plate were numerically studied in the present paper and the results were compared with those of a traditional trench laying cable. The variations of conductor loss and eddy current loss of different loop cables were discussed in the trench with a ceramic plate, and the effects of ceramic plate parameters on heat transfer performance of the trench laying cable were optimized using the Taguchi method. It is found that for the trench with ceramic plates, although the ceramic plate restrains the natural convection in the trench, the total heat transfer for natural convection and thermal radiation are enhanced for the cables and the cable ampacity can be improved. The difference of electromagnetic loss between the upper- and lower-layer cables in the trench with ceramic plate is quite small. When the cable core current (I) increases from 700 A to 1100 A, the maximum difference of averaged electromagnetic loss between the upper- and lower-layer cables is 1.22%. With the Taguchi method, an optimum parameter combination is obtained. When the length, thickness, and surface emissivity of the ceramic plate are equal to 0.48 m, 0.0734 m, and 0.8, respectively, at I = 900 A, the cable maximum temperature in the trench is the lowest.

Preparation and Mechanical Property of Alumina Fibers Reinforced Thin Architectural Ceramic Plate

The fibers reinforced thin architectural ceramic plate of 900 mm×1800 mm×2.5 mm with high mechanical property was prepared by a fast-sintering method with a controllable fiber dispersion process. The effects of ball-milling time to the dispersity, average length-diameter ratio and microstructure of alumina fibers were investigated respectively. Meanwhile, the alumina fiber contents to the volume density, water absorption, phase transformation and microstructure of the thin ceramic plate were researched. It is found that the two-steps ball-milling process can control the average length-diameter ratio of the alumina fibers effectively and achieve a well dispersion mixture of fibers and ceramic powders, the fast-sintering method is beneficial for the protection of fiber/matrix interface. The trend of the volume density and bending strength increases with the fiber content from 0 wt% to 5 wt% and then decreases with the fiber content from 5 wt% to 15 wt%. The bending strength of this composite reaches the maximum value of 146.8 MPa with the fiber content is 5 wt%, which is corresponding to the strengthening of alumina fibers and the formation of mullite crystallization in fiber/matrix interface and matrix during the fast-sintering process.

Influence of the Microstructure of Cutting Ceramics on the Efficiency of the Machining Process

The article deals with the determination of the efficiency of a multi-bladed tool equipped with inserts made of oxide-carbide cutting ceramics, depending on the microstructural parameters of the tool material. The microstructural parameters of the oxide-carbide cutting ceramic, which affect the performance of the tool, are proposed to be determined according to the electrical resistance of the tool material. In order to implement the method for determining the working capacity of the instrument, a basic design of the device for measuring the electrical resistance of the material of the instrument is proposed. The device for measuring the electrical resistance of ceramic plates consists of a body made of a dielectric material, with channels for supplying a conductive material and a groove for installing a case with a test sample. During the test, the channels are filled with a liquid conductive material, which fills the cavity formed by the channel of the case, the groove of the case and the plate itself under test. To ensure uniform filling of the cavity, after the introduction of the liquid conductive material, metal balls are installed into the channels, which are made in such a size as to ensure free sliding along the channel, but not to let the liquid pass into the upper part of the channel. The tested ceramic plate is installed in the walls of the removable case. The walls of the removable case include electrodes, which, when the device is in operation, are inserted into a cavity with a liquid conductive material at one end, and are connected to an ohmmeter at the other. Using a device for measuring the electrical resistance of ceramic plates, it is possible to determine the operability of the tool and guarantee its operation without rejection for a certain period of time, which was confirmed by experimental research in the milling of workpieces of machine parts made of gray cast iron. Experimental studies in multi-edge machining with cutters with different values ​​of electrical resistance of ceramic plates made it possible to plot graphs of the dependence of the quality of machining during milling on the operability of the tool and on the time of the machining process.