Applicability of Measurements of Local Electrical Parameters in the Modeling of Technological Texture of Ceramic Blanks

2019 ◽  
Vol 952 ◽  
pp. 346-355
Author(s):  
Tomáš Kozík ◽  
Stanislav Minárik ◽  
Peter Kuna ◽  
Marián Kubliha
Keyword(s):  
Graphical Representation ◽  
Field Potential ◽  
Axial Direction ◽  
Sample Surface ◽  
Ceramic Materials ◽  
Axial Texture ◽  
Technology Preparation ◽  
Dielectric Sample ◽  
Center Electrode

The paper deals with the modeling of the technological texture of the pressed ceramic materials in the radial and axial direction, which consists in the graphical representation and subsequent analysis of the distribution of the electrostatic field potential differences on the surface of the dielectric sample with the diameter d and the thickness h located between the electrodes. In occasion of observing radial texture the electrodes have the cylindrical configuration and in occasion of observing the axial texture in the sample the electrodes have the axial configuration. The theoretical relationship in the paper is derived for the calculation of the voltage values measured at any position between the center electrode and the peripheral electrode, at a constant voltage U applied to the outer and inner electrodes of the dielectric sample of thickness h of the raw ceramic sample material (radial texture). Measurements have demonstrated the suitability of identifying the technological texture by measuring the potential differences on the sample surface which is located between the electrodes in the relation to the technology preparation and to the quality of the fired ceramic production.

Investigation and Characterization of Clay Mixture Feedstock for Extrusion-Based Additive Manufacturing

2020 ◽  
Author(s):  
Tawaddod Alkindi ◽  
Mozah Alyammahi ◽  
Rahmat Agung Susantyoko
Keyword(s):  
Cost Efficiency ◽  
Ceramic Materials ◽  
3D Printer ◽  
Mixing Processes ◽  
Ceramic Components ◽  
Computer Controlled ◽  
Continuous Material ◽  
Printing Speed

Abstract The extrusion-based AM technique has been recently employed for rapid ceramic components fabrication due to scalability and cost-efficiency. This paper investigated aspects of the extrusion technique to print ceramic materials. Specifically, we assessed and developed a process recipe of the formulations (the composition of water and ethanol-based clay mixtures) and mixing processes. Different clay paste formulations were prepared by varying clay, water, ethanol ratios. The viscosity of clay paste was measured using a DV3T Viscometer. Afterward, the produced clay paste was used as a feedstock for WASP Delta 60100 3D printer for computer-controlled extrusion deposition. We evaluated the quality of the clay paste based on (i) pumpability, (ii) printability, and (iii) buildability. Pressure and flow rate were monitored to assess the pumpability. The nozzle was monitored for continuous material extrusion to assess printability. The maximum layer-without-collapse height was monitored to assess the buildability. This study correlated the mixture composition and process parameters, to the viscosity of the mixture, at the same printing speed. We found that 85 wt% clay, 5 wt% water, 10 wt% ethanol paste formulation, with the viscosity of 828000 cP, 202400 cP, 40400 cP at 1, 5, and 50 rpm, respectively, demonstrates good pumpability, as well as best printability and buildability.

Reaction Kinetics for the Hydrolysis of Titanium Isopropoxide Carboxylate Complexes

1992 ◽  
Vol 271 ◽  
Author(s):  
Charles D. Gagliardi ◽  
Dilum Dunuwila ◽  
Beatrice A. Van Vlierberge-Torgerson ◽  
Kris A. Berglund
Keyword(s):  
Carboxylic Acids ◽  
Ceramic Materials ◽  
Titanium Isopropoxide ◽  
General Interest ◽  
Chemical Transformations ◽  
Molecular Precursors ◽  
Novel Applications ◽  
Kinetics Of ◽  
Hydrolysis Of

ABSTRACTTitanium alkoxides modified by carboxylic acids have been widely studied as the molecular precursors to ceramic materials. These alkoxide complexes have also been very useful in the formation of stable, porous, optically clear films having many novel applications such as chemical sensors, catalytic supports, and ion-exchange media. To improve the processing of these materials, it is essential to better understand the kinetics of the chemical transformations which occur.The kinetics of the hydrolysis reaction are studied for selected carboxylic acids using Raman spectroscopy to probe the chemistry of the process. The study has a special emphasis on the titanium isopropoxide-valeric acid system due to the superior quality of these films over other carboxylates. Greater knowledge of the hydrolysis kinetics allows increased control over the quality of the film materials and should be of general interest to those working with modified metal alkoxides.

scholarly journals CONSULTING IN THE UKRAINIAN MARKET OF SERVICES AND ITS COMPETITIVE ADVANTAGES

2021 ◽  
Vol 7 (4) ◽  
pp. 72-84
Author(s):  
Natalia Yevtushenko ◽  
Tatiana Halimon
Keyword(s):  
Competitive Advantage ◽  
Graphical Representation ◽  
Quality Of Services ◽  
Expert Assessment ◽  
Target Market ◽  
Competitive Advantages ◽  
Competitive Strategies ◽  
Consulting Services ◽  
Practical Recommendations

The article summarizes the arguments and counterarguments about the peculiarities of formation of competitive advantages on the services market in Ukraine on the example of consulting. Assessment of the development of consulting services market in Ukraine was conducted for ten years (2010; 2011; 2012; 2013; 2013; 2014; 2015; 2016; 2017; 2018; 2019, 2020). Methodology. The use of methods of analysis, synthesis and graphical representation allowed for a theoretical study of the formation of competitive advantages. The use of methods of economic, heuristic and strategic analysis became the basis for estimating the market of consulting services in Ukraine and working out practical recommendations for its development. Results. The author's understanding of the concept of "competitive advantages of the company", the factors of their formation and described the relationship of competitive strategies with the process of their formation. Analysis of the market of consulting services in Ukraine revealed its immaturity, exacerbated by the economic crisis, as well as the institutional vulnerability of consulting. The reasons of unstable demand for consulting services are described. According to the results of the expert assessment the Top 15 Ukrainian consulting companies (2020) out of 102 were determined. The leadership matrix of these companies is built depending on their role in the target market, taking into account the typology of competitive strategies of F. Kotler. The analysis showed the transformation of consulting in Ukraine under the influence of the COVID-19 pandemic and the broad interest in digital and HR consulting. Practical recommendations for the development of the market of consulting services in Ukraine are presented. Practical implications. It is proposed to include the following factors in the formation of the competitive advantages of the consulting company: the quality of services, competence of consultants and productivity of the company. The main competitive advantage is the competence of consultants, the level of which affects the quality of services, the results of the company and its customers. To strengthen the competitive advantage it is recommended to use the standard of consulting services in the activities of Ukrainian companies. Value/originality. The results of the study can be useful for any consulting company wishing to improve its competitiveness and expand the market for its services.

Features of Distance Learning in Geometric and Graphic Disciplines Using Methods of Constructive Geometric Modeling

2021 ◽  
pp. 46-56
Author(s):  
E. Boyashova
Keyword(s):  
Distance Learning ◽  
Geometric Modeling ◽  
Information Technologies ◽  
Graphical Representation ◽  
Teaching Experience ◽  
Educational Process ◽  
Descriptive Geometry ◽  
Geometric Constructions ◽  
Professional Activities

The article is devoted to the peculiarities of teaching the discipline "Descriptive geometry" in the conditions of distance learning, it examines the application of information technologies in the educational process in geometric and graphic disciplines. Increasing the speed of information processes, reducing the number of hours for mastering the discipline. the conditions of distance learning set new tasks for teachers and dictate their requirements for teaching graphic disciplines and the use of teaching experience in a new reality; there is a need to introduce and develop new forms of education without losing the quality of education. Geometric-graphic disciplines occupy one of the important places in technical education, the complexity of the study of which lies in the development of a graphical representation of phenomena, objects and processes by methods of constructive geometric modeling. The knowledge and skills acquired by students contribute to the development of spatial, imaginative and rational thinking, which is necessary for future professional activities. Descriptive geometry is a discipline that is not easy to master on your own without a conscious understanding of the logic and sequence of geometric constructions, without deep knowledge of theoretical foundations and constant, repeated implementation of practical tasks. The acquisition of practical skills in mastering the methods of discipline has become more difficult in the current epidemiological situation. In modern conditions of distance learning, the use of the Simplex geometric modeling system made it possible to develop and propose a new concept of geometric-graphic interaction, which significantly reduced the time for completing and checking educational tasks in real time. The proposed technology reveals the deep informational essence of the studied discipline "Descriptive Geometry" and becomes a powerful research tool for students. The integration of traditional teaching methods in the graphic preparation of students with computer and communication facilities increases the possibilities of communication and improves the quality of teaching.

Optimising the Growth of Few-Layer Graphene on Silicon Carbide by Nickel Silicidation

2013 ◽  
Vol 740-742 ◽  
pp. 121-124 ◽  
Author(s):  
Enrique Escobedo-Cousin ◽  
Konstantin Vassilevski ◽  
Toby Hopf ◽  
Nick G. Wright ◽  
Anthony O’Neill ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Solid Phase ◽  
Sample Surface ◽  
Device Fabrication ◽  
Solid Phase Epitaxy ◽  
X Ray ◽  
Graphene Films ◽  
Few Layer Graphene ◽  
The Impact

Few-layers graphene films (FLG) were grown by local solid phase epitaxy on a semi-insulating 6H-SiC substrate by annealing Ni films deposited on the Si and C-terminated faces of the SiC. The impact of the annealing process on the final quality of the FLG films is studied using Raman spectroscopy. X-ray photoelectron spectroscopy was used to verify the presence of graphene on the sample surface. We also demonstrate that further device fabrication steps such as dielectric deposition can be carried out without compromising the FLG films integrity.

The Quality of Brazed Ceramic and Cemented Carbide Joints - A Mechanical and Metallurgical Assessment

2010 ◽  
Vol 64 ◽  
pp. 108-114 ◽  
Author(s):  
Wolfgang Tillmann ◽  
Lukas Wojarski ◽  
Benjamin Lehmert
Keyword(s):  
Thermal Stresses ◽  
Mechanical Performance ◽  
Ceramic Materials ◽  
Mechanical Tests ◽  
Point Of View ◽  
Cemented Carbides ◽  
Full Potential ◽  
Ceramic Surface ◽  
Reaction Products

The availability of adequate joining technologies is of major importance in order to exploit the full potential of ceramic materials. The same is true for joints between cemented carbides and their counterparts. Such joints are not easy to manufacture due to wetting and bonding problems as well as induced thermal stresses. Currently, active brazing is a potential approach for fabricating such joints. The filler alloy contains reactive agents such as Titanium or Hafnium etc. that interact by forming wettable reaction layers on the ceramic surface. It is self-evident that they function very well on cemented carbides as well. The paper describes potential wetting and bonding reactions from a metallurgical point of view. Ceramics, superabrasive and cemented carbides are investigated with respect to interfacial reactions. The quality of the reaction products is of crucial importance regarding the mechanical performance of the joints, as their immanent brittleness can lead to a significant weakening. Apart from metallurgical assessments, mechanical tests are conducted in order to deliver data for their integration in hybrid structures. FE methods can be applied to assess the stress situation in the final joint. Thus it is possible to adjust the design accordingly.

Influence of the Temperature in the Direct Forming Laser Process of 316L Stainless Steel with CO2 Laser

2014 ◽  
Vol 802 ◽  
pp. 334-337
Author(s):  
C.L. Santos ◽  
G. Vasconcelos ◽  
H.S. Oliveira ◽  
L.G. Oliveira ◽  
J.F. Azevedo ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Melting Point ◽  
Laser Beam ◽  
316L Stainless Steel ◽  
Turbine Blades ◽  
Scanning Speed ◽  
Sample Surface ◽  
Laser Process

This study shows the influence of the temperature in the Direct Forming Laser process (DFL) of 316L stainless steel metal powder. Results shows that an increasing in the sample surface temperature can improve the laser beam absorption in the DFL process. A pre-heating in the substrate and in the powder contributed to decrease the time to reach the melting point and to improve the surface roughness. This effect was investigated with constant lasers parameters (scanning speed and intensity) and a heating in the samples in the temperature range of 20oto 200oC. It was possible to evaluate the DFL process and to optimize the quality of the sample surface roughness. These results will benefit the knowledge of the DFL technology that can be applied in the development of turbine blades.

Heat and Mass Transfer during Drying of Clay Ceramic Materials: A Three-Dimensional Analytical Study

2017 ◽  
Vol 10 ◽  
pp. 93-106 ◽  
Author(s):  
M.K. Teixeira de Brito ◽  
D.B. Teixeira de Almeida ◽  
A.G. Barbosa de Lima ◽  
L. Almeida Rocha ◽  
E. Santana de Lima ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Analytical Study ◽  
Separation Of Variables ◽  
Three Dimensional ◽  
Ceramic Materials ◽  
Governing Equations ◽  
Convective Boundary ◽  
Good Agreement

This work aims to study heat and mass transfer in solids with parallelepiped shape with particular reference to drying process. A transient three-dimensional mathematical model based on the Fick ́s and Fourier ́s Laws was developed to predict heat and mass transport in solids considering constant physical properties and convective boundary conditions at the surface of the solid. The analytical solution of the governing equations was obtained using the method of separation of variables. The study was applied in the drying of common ceramic bricks. Predicted results of the heating and drying kinetics and the moisture and temperature distributions inside the material during the process, are compared with experimental data and good agreement was obtained. It has been found that the vertices of the solid dry and heat first. This provokes thermal and hydric stresses inside the material, which may compromise the quality of the product after drying.

Long-Haul Endurance

2002 ◽  
Vol 124 (08) ◽  
pp. 50-51
Author(s):  
John DeGaspari
Keyword(s):  
National Laboratory ◽  
Argonne National Laboratory ◽  
Ceramic Materials ◽  
Heavy Duty ◽  
Laser Technique ◽  
Early Failure ◽  
Heavy Duty Truck ◽  
Ceramic Components ◽  
Better Than

This article reviews that lasers are being investigated as a way to uncover tiny imperfections in crucial ceramic components of diesel engines. Heavy-duty truck engines are designed to operate for a million miles or more. In their search for components that resist corrosion and wear, manufacturers have developed engine parts from ceramics, which have found their way into a number of commercial engine applications over the last 10 years. Under some conditions, the materials hold up better than steel, but they are not immune to weaknesses of their own. The machining of ceramic parts, for example, can leave them with flaws that lead to early failure and defeat their purpose. The laser technique being developed at Argonne National Laboratory is intended to inspect the quality of ceramic parts after they are machined. So far, the laser technique has been developed to look for imperfections in silicon nitride, silicon carbide, and zirconia, among other ceramic materials.

scholarly journals The examination of the effect of variable cutting speeds on the surface and edge qualities of milled granite materials

2019 ◽  
Vol 11 (7) ◽  
pp. 168781401983631 ◽  
Author(s):  
István Gábor Gyurika ◽  
Tibor Szalay
Keyword(s):  
Surface Roughness ◽  
Cutting Speed ◽  
Sample Surface ◽  
Average Surface Roughness ◽  
Edge Chipping ◽  
Average Surface ◽  
Grain Sizes ◽  
Natural Stones ◽  
Cutting Speeds

Automated stone manufacturing has undergone considerable development in recent years. Thanks to international research dealing with the cutting, sawing and grinding of different natural stones, processing time shortens and tool-life lengthens. However, the process of stone milling has not been extensively examined yet, primarily because of the novelty of this technology. The aim of the research described in this article is to examine how variable cutting speed affects the quality of workpiece edges while milling granite materials. For the research, sample surfaces were formed on five granite slabs with different average grain sizes using five cutting speed values. Afterwards, changes in the average surface roughness and average edge chipping rate were examined. From the research results, it can be concluded that, due to an increase in cutting speed, the average edge chipping rate will decrease until reaching a borderline speed. In the case of a higher cutting speed, the referent tendency cannot be ascertained. A statistical analysis conducted in the scope of this research showed that if a variable cutting speed is applied, then changes in the quality of the sample surface edge can be inferred from the development trends of average surface roughness.

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