Papers by Keyword: Thickness

Abstract: This study presents a real-time method for determining the thickness of each layer in multilayer thin films. Artificial neural networks (ANNs) were introduced to estimate thicknesses from a transmittance spectrum. After training via theoretical spectra which were generated by thin-film optics and modified by noise, ANNs were applied to estimate the thicknesses of four-layer nanoscale films which were TiO₂, Ag, Ti, and TiO₂ thin films assembled sequentially on polyethylene terephthalate (PET) substrates. The results reveal that the mean squared error of the estimation is 2.6 nm², and is accurate enough to monitor film growth in real time.

Abstract: For the rehabilitation and renovation of sewerage and gutter networks, different methods and technologies have been introduced over the last half-century. The trenchless technologies are showing the greatest development. They are promoted for reasons of environmental friendliness, they do not restrict the space in the place of renovation and the implementation is fast. The paper focuses on specific material starting points for the use of trenchless methods. Trenchless methods do not generate waste from original pipelines. New pipes are installed in the existing pipeline, or a new pipeline pushes the old profile into the surrounding area. However, the new pipeline is not accessible for the traditional methodology of result control and product performance verification. Particularly for Cured-in-Place-Pipe (CIPP) methods, it is difficult to determine representative quantities for key features such as the thickness of the sanitary insets (sleeves) after curing, and it follows from practice that the measurements should be performed with a special spike gauge. CIPP products achieve all the final properties through the installation process in the existing pipeline. Simulation on semi-operative polygons is increasingly being used for research and verification of suitable representatives. Authors of the article began to address this issue in research, in collaboration with the company WOMBAT, s.r.o. when investigating the higher resistance of CIPP lining.

Abstract: Control rod drive mechanism is one of the key main components in nuclear power plants and serves in harsh environments such as high temperature, high pressure and nuclear radiation. In order to ensure the service life and to prevent biting when assembling, some of the threads of control rod drive mechanism need to be chromium plated. In view of the high demands of the same chromium plating thickness on all surfaces of the threads of control rod drive mechanism of nuclear power and non-uniformity in chromium plating thickness of threads due to poor throwing power of chromium plating solution, five representative kinds of threads of control rod drive mechanism were selected and the plating thickness change of the root diameter, pitch diameter and crest diameter of threads was studied in this paper by means of depositing different thickness chromium coating on the surface of threads. The experimental results show that thicker coating is deposited on the crest of thread because of high current density and thinner coating is deposited on the root of thread because of low current density, which can provide reference for specification of chromium plating thickness of thread products of control rod drive mechanism.

Abstract: In scientific work has been developed a thickness calculation procedure of an aluminum thermal spray coating, sprayed on the low-alloyed steel surfaces in order to provide its effective protection at hight temperatures. The method is based on the calculations of the diffusion layer thickness with consideration of temperature change on the blank`s surface and on the dependence of the parameter (directly proportional to the diffusional coefficient) on the temperature.

Abstract: Incremental sheet metal forming, is a non-conventional machining process which offers higher formability, flexibility and low cost of production than the traditional conventional forming process. Punch or tool used in this forming process consecutively forces the sheet to deform locally and ultimately gives the target profile. Various machining parameters, such as type of tool, tool path, tool size, feed rate and mechanical properties of sheet metal, like strength co-efficient, strain hardening index and ultimate tensile strength, effects the forming process and the formability of final product. In this research paper, Single Point Incremental Forming was simulated using Dassault system’s Abaqus 6.12-1 and results are obtained. Results of sheet profile and there change in thickness is investigated. For this paper, we simulated the process in abaqus. The tool diameter and rotational speed is find out for the production of parts through incremental forming. The simulation is done for two type of material with different mechanical properties. Various research papers were used to understand the process of incremental forming and its simulation.

Abstract: The third octave sound absorption coefficient testing is conducted to compare the sound absorption properties metal foam and flexible cellular materials, by using sound absorption tester with the method of trasfer function sound absorption tester with the method of trasfer function. The sound absorption mechanisms are discussed by changing the parameters of sound absorption structure, such as the thickness of matrix materials and the thickness of cavity. The results show that pearl wool and glass wool exhibited excellent sound absorption properties. The peak value of sound absorption coefficient for pearl wool reaches to 0.991, and for glass wool, 0.985. The average sound absorption coefficient for pearl wool is 0.729, and for glass wool, 0.679. Among of three metal foams, the foamed aluminum material exhibited optimum sound absorption properties, and is superior to flexible sound absorption materials. The peak value of sound absorption coefficient reaches to 0.993, and the average value reaches to 0.781. This can be attributed to the flow resistance, porosity, thickness, cavity and structure factor, which influence the sound absorption of open cell materials.

Abstract: In the present scientific work a thickness calculation procedure of an aluminum gas-thermal coating, sprayed on the low-alloyed steel surfaces, in order to provide its effective protection at high temperatures, has been developed. The method is based on the calculations of the diffusion layer thickness with consideration the temperature change on the blank`s surface and on the dependence of the parameter (directly proportional to the diffusion coefficient) on the temperature over the range 700 to 1200 °C.

Abstract: Experimental studies of the dependence of the deformation ε1max on the strain σ and the relative changes in the width and thickness of the unirradiated and irradiated polytetrafluoroethylene film on the relative elongation are carried out. It was found that these quantities depend essentially on the load. The curves obtained are satisfactorily described by a linear model.

Abstract: In this study, a steel for semiprocessed electrical purposes of non-oriented grain with approximately 0.05% carbon content and 0.02% silicon content was evaluated. Lamellas with kind of thicknesses 0.58 mm, 0,66 mm and 0.87 mm were processed on an industrial scale with a strain rate in the hardening lamination between 3 and 5%. The magnetic properties were evaluated after the wet heat treatment. The loss separation method was applied, estimating the hysteretic plot with hysteresis measure in the quasi static condition and the parasitic losses calculated according to Thomson's Equation. By increasing grain size, permeability increases and coercivity decreases. However, in the case of losses, there is an optimum grain size. After the procedure of separation of losses, it was observed that increase of thickness results in increase of the anomalous parcel of magnetic losses.

Abstract: We report on the results of a Design of Experiments (DOE) matrix of growth runs used to tune and improve the uniformity of thickness and doping across both 100 mm and 150 mm SiC epiwafers in our epitaxy reactor. Improvement of uniformity beyond the initial process recipe from the tool vendor is shown. Temperature measurement along an entire wafer platter indicate that there is a gas cold region extending into the growth zone that maybe the root cause of the non-uniformity.