Development of the Servo Valve with High Durability Using Split-Type Sleeve – Reduction of Wear with Ceramic Material –

Reduction of leakage is a major problem in water hydraulic systems. With a servo valve, it is possible to reduce the internal leakage by reducing the clearance between a spool and a sleeve. However, because the clearance is reduced, wear tends to occur easily between the spool and sleeves when the servo valve is driven. As a result, the durability of the servo valve is reduced. Attention is paid to the durability against wear of ceramic materials, and the wear can be suppressed by using ceramics as the materials of the spool and sleeve. Thus, one can check whether the wear between the spool and sleeve can be suppressed, thereby improving the durability of the servo valve.

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Investigation on Velocity Response and Energy Saving Performance of Water Hydraulic Systems Without Using Servo Valve

Proceedings from the 13th Scandinavian International Conference on Fluid Power, June 3-5, 2013, Linköping, Sweden ◽

10.3384/ecp1392a41 ◽

2103 ◽

Author(s):

Pha N Pham ◽

Kazuhisa Ito ◽

Shigeru Ikeo

Keyword(s):

Energy Saving ◽

Hydraulic Systems ◽

Servo Valve ◽

Velocity Response ◽

Water Hydraulic

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Servo valve endurance test for water-hydraulic systems in ITER-relevant conditions

Fusion Engineering and Design ◽

10.1016/j.fusengdes.2019.04.033 ◽

2019 ◽

Vol 146 ◽

pp. 2523-2526 ◽

Cited By ~ 1

Author(s):

Liisa Aha ◽

Jukka Väyrynen ◽

Jyrki Tammisto ◽

Jouni Mattila ◽

Salvador Esqué ◽

...

Keyword(s):

Hydraulic Systems ◽

Endurance Test ◽

Servo Valve ◽

Water Hydraulic

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Numerical Modeling and Experimental Characterization of the Pyroplasticity in Ceramic Materials during Sintering

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.62.203 ◽

2010 ◽

Vol 62 ◽

pp. 203-208 ◽

Cited By ~ 3

Author(s):

Pasquale Bene ◽

Danilo Bardaro ◽

Daniela Bello ◽

Orazio Manni

Keyword(s):

Ceramic Material ◽

Ceramic Materials ◽

Constitutive Law ◽

Beam Deflection ◽

Firing Cycle ◽

Experimental Characterization ◽

Viscosity Increase ◽

Ceramic Components ◽

Deflection Theory ◽

Sintering Shrinkage

The aim of the work is the study of the pyroplasticity in ceramic materials in order to simulate the deformations of complex ceramic component during sintering. A ceramic material undergoing densification can be treated as a linear viscous material. Generally, the viscosity decreases as the temperature increases, however the densification and the consequent grain growth, result in a viscosity increase. A bending creep test is proposed for measuring the change in viscosity of the ceramic material during densification. Equations, based on beam deflection theory, are derived to determine the viscosity during the whole firing cycle by measuring the deflection in the centre of specimens. In addition, dilatometric analyses are performed to measure the sintering shrinkage and the specimen density, which continuously changes during the sintering process. On the basis of an accurate experimental characterization the parameters of Maxwell viscoelastic constitutive law are derived. A numerical-experimental procedure has been adopted in order to calibrate the numerical model that, finally, has been used to predict the pyroplastic deformations of complex ceramic components.

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Application of Focus-Variation Technique in the Analysis of Ceramic Chips

Materials Science Forum ◽

10.4028/www.scientific.net/msf.957.187 ◽

2019 ◽

Vol 957 ◽

pp. 187-194

Author(s):

Roman Wdowik ◽

Slawomir Swirad

Keyword(s):

Machine Tool ◽

Ceramic Material ◽

Microscopic Study ◽

Ceramic Materials ◽

Software Tools ◽

Milling Machine ◽

Focus Variation ◽

3D Scans ◽

Physical Phenomena ◽

Variation Technique

The paper presents the method of a microscopic study of ceramic chips which can be useful in the analysis of physical phenomena regarding machining of ceramic materials. The analyzed chips were obtained on the milling machine tool from the Al2O3 based ceramic material. The measurements were performed using focus-variation technique (FVT). The InfiniteFocus Real3D microscope from Alicona Imaging company was applied. The paper mainly focuses on the methodology of measurements and the application of microscope’s software tools which can be used in the analysis of chips' 3D scans. The conditions of measurement process are discussed on the basis of the results of exemplary measurements of ceramic chips.

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Treatment of Soil Contaminated by Mining Activities to Prevent Contamination by Encapsulation in Ceramic Construction Materials

Materials ◽

10.3390/ma14226740 ◽

2021 ◽

Vol 14 (22) ◽

pp. 6740

Author(s):

Juan María Terrones-Saeta ◽

Jorge Suárez-Macías ◽

Antonio Bernardo-Sánchez ◽

Laura Álvarez de Prado ◽

Marta Menéndez Fernández ◽

...

Keyword(s):

Ceramic Material ◽

Contaminated Soil ◽

Toxic Elements ◽

Construction Materials ◽

Well Being ◽

Ceramic Materials ◽

Potentially Toxic Elements ◽

Raw Material ◽

Mining District ◽

Different Soils

Mining is an essential activity for obtaining materials necessary for the well-being and development of society. However, this activity produces important environmental impacts that must be controlled. More specifically, there are different soils near new or abandoned mining productions that have been contaminated with potentially toxic elements, and currently represent an important environmental problem. In this research, a contaminated soil from the mining district of Linares was studied for its use as a raw material for the conforming of ceramic materials, bricks, dedicated to construction. Firstly, the contaminated soil was chemically and physically characterized in order to evaluate its suitability. Subsequently, different families of samples were conformed with different percentages of clay and contaminated soil. Finally, the conformed ceramics were physically and mechanically characterized to examine the variation produced in the ceramic material by the incorporation of the contaminated soil. In addition, in this research, leachate tests were performed according to the TCLP method determining whether encapsulation of potentially toxic elements in the soil occurs. The results showed that all families of ceramic materials have acceptable physical properties, with a soil percentage of less than 80% being acceptable to obtain adequate mechanical properties and a maximum of 70% of contaminated soil to obtain acceptable leachate according to EPA regulations. Therefore, the maximum percentage of contaminated soil that can be incorporated into the ceramic material is 70% in order to comply with all standards. Consequently, this research not only avoids the contamination that contaminated soil can produce, but also valorizes this element as a raw material for new materials, avoiding the extraction of clay and reducing the environmental impact.

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Effect of LiNbO3 on the Electrocaloric Performance of 0.94BNT-0.06BT Ceramic Materials

10.21203/rs.3.rs-437223/v1 ◽

2021 ◽

Author(s):

Jing Chen ◽

lei Wu ◽

Luanfan Duan ◽

Dongren Liu

Keyword(s):

Ceramic Material ◽

Room Temperature ◽

Ceramic Materials ◽

Adiabatic Temperature ◽

Cooling Effect ◽

Material System ◽

Temperature Changes ◽

Cooling Temperature ◽

Temperature Range

Abstract Considering that the electric refrigeration temperature range of 0.94BNT-0.06BT ceramic materials is 100 ~ 140℃, the electric refrigeration performance of the 0.94BNT-0.06BT ceramic material system was modified by LiNbO3 doping to reduce the cooling temperature. As a result, the refrigeration temperature range of the 0.94BNT-0.06BT ceramic material system was lowered to 25 ~ 80℃, achieving its cooling effect near room temperature, and in this temperature range, the adiabatic temperature changes ∆T > 0.6K.

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Preparation of Macroporous Ceramic Materials by Using Aluminium Powder as Foaming Agent

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.699.336 ◽

2014 ◽

Vol 699 ◽

pp. 336-341 ◽

Cited By ~ 1

Author(s):

Nurulfazielah Nasir ◽

Ridhwan Jumaidin ◽

Hady Efendy ◽

Mohd Zulkefli Selamat ◽

Goh Keat Beng ◽

...

Keyword(s):

Ceramic Material ◽

Reaction Rate ◽

Porous Alumina ◽

Porous Ceramic ◽

Ceramic Materials ◽

Calcium Sulphate ◽

Alumina Ceramic ◽

Deionized Water ◽

Foaming Agent ◽

Aluminium Powder

Aluminium powder was used as foaming agent in the production of macro-porous alumina ceramic. The porous ceramic material was developed by mixing an appropriate composition of cement, aluminium powder (Al), alumina (Al2O3), calcium oxide (CaO), gypsum (calcium sulphate dehydrate, CaSO4.2H2O), silica powder and deionized water. Different compositions of porous ceramic were produced at 2wt.%, 3wt.% and 4wt.% of aluminium powder. Their mechanical properties and macro-porosity structural of the porous ceramic material were analysed and compared. It is determined that the optimal properties of porous ceramic material were found at 3wt.% of aluminium powder and degraded drastically at 4wt.%. This phenomenon is due to the chemical reaction between the aluminium powder and DI water in which they form aluminium oxide that promotes the strength of the material but at the same time, more pores are created at higher reaction rate between these two fundamental materials.

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Próteses parciais fixas metal free em região posterior – revisão da literatura considerando a longevidade, material cerâmico usado e principais falhas

Full Dentistry in Science ◽

10.24077/2021;1247113125 ◽

2021 ◽

Vol 12 (47) ◽

pp. 113-125

Author(s):

Nathalia Silveira Finck ◽

Juliana da Mota Paiva ◽

Rafael Dario Werneck ◽

Mariana Itaborai Moreira Freitas ◽

Priscilla Santos Guimarães

Keyword(s):

Ceramic Material ◽

Ceramic Materials ◽

Inclusion Criteria ◽

Electronic Library ◽

Metal Free ◽

Significant Difference ◽

Bibliographical Survey ◽

Observation Period

This study aimed to present a literature review with data obtained in vitro and in vivo on metal free partial fixed protheses (PFP) in the posterior region, considering the following variables: ceramic material to be used; prosthesis extension; survival or longevity; main failures found, and comparison with the longevity of conventional metaloceramic PFP. A bibliographical survey was carried out using the databases: United States National Library of Medicine (PubMed) and Scientific Electronic Library Online (Sciello) for articles in English and Portuguese from 1998 to 2019. Articles should meet the inclusion criteria, which were articles that contained information that enabled the calculation of PFPs survival and success, articles with a minimum observation period of 3 years, articles that identified the reason of failures, and studies reported since 1998. Sixteen studies met the inclusion criteria and were evaluated comparatively. The survival rate of the PFP’s varies depending on the ceramic material used and the prostheses extension, no significant difference was observed in the relation between the ceramic material used and the connectors size; however, the greater the extension of the prosthesis, the higher must be the connector size. It was concluded that ceramic materials based on zirconia are the ones that have the longest survival. In addition, the main reasons that lead to decreased survival of PFP’s are secondary caries and connector fracture, however, more studies are needed to determine safely which materials and the extent of PFP’s are the most indicated.

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