Ceramic Cover Research Articles

Extracting salt from soil with ceramic sheets

The study investigates the drying behavior and desalination effectiveness of porous ceramic tiles made from fired clay materials like bricks or pottery on soil columns initially saturated with saline solution. Evaporation kinetics experiments compared the drying of saline soil with and without a ceramic tile. For soil without a ceramic cover, salt precipitation formed an efflorescent crust that initially (t ∼ 30 h) reduced the evaporation rate. However, with continued drying, the tensile stress caused cracks in the crust, allowing increased evaporation through the cracks (t > 200 h). When covered with a ceramic poultice, the saline solution was wicked into the porous ceramic by capillary action. Rapid salt efflorescence was observed on the ceramic surface. The ceramic layer initially reduced the soil evaporation rate due to pore clogging caused by salt precipitation. The pore structure characteristics of the ceramics significantly impacted their desalination performance. After an initial fast drying period controlled by evaporation, a reduced drying rate was observed as salt clogging effects became dominant, especially for the low porosity ceramic (t ∼20 h). The porous ceramic poultices could effectively extract salts from the soil, but their desalination efficiency depended critically on their pore structure properties. An industrial-based clay ceramic with large and more connected pores (porosity 0.33) was found to be around 62% more efficient in removing NaCl than a handmade pottery with small pores (porosity 0.18).

Assessing the risks associated with indoor and outdoor air quality in relation to the geographic placement of nursing home

Indoor air quality significantly impacts the well-being and health of elderly residents in nursing homes. This study was conducted to explore the connection between indoor and outdoor PM (Particulate Matter) concentrations in nursing homes and their association with the facilities' location and construction characteristics. The findings revealed that indoor PM2.5 and PM10 concentrations ranged from 0.2 to 124 μg/m3 and 2–188.4 μg/m3, respectively, which were approximately 12.67 and 1.25 times higher than their outdoor counterparts. A strong correlation (P < 0.05) was identified between indoor PM levels and various factors, including proximity to parks, passenger terminals, and gas stations, as well as building attributes such as single-glazed windows, ceramic floor coverings, and the use of radiators. The risk assessment indicated that carcinogenic risk factors were well within acceptable limits for all nursing homes. However, it's important to note that certain PM components, particularly polycyclic aromatic hydrocarbons (PAH), may have long-term adverse effects on the health of nursing home residents. Even though indoor PM levels met the standards established by the U.S. Environmental Protection Agency (USEPA) for particulate matter risk assessments, the study emphasized that even low levels of indoor air pollutants can affect the health and well-being of older adults, particularly considering the increased vulnerability associated with aging. Consequently, the study underscores the importance of nursing home location selection and the regular monitoring of particulate matter concentrations. These measures are essential for enhancing air quality within nursing homes, ultimately contributing to the improved well-being and health of their residents.

Structural transformation of dusty plasma crystal in dc discharge plasma by changing confinement ring bias

We report an experimental study of the structural transition of a stable complex plasma crystal to a solid-liquid phase coexistence by the controlled adjustment of the confinement potential, while keeping all other parameters constant. The experiments are carried out on a tabletop linear dusty plasma experimental device, which consists of a circular powered electrode and an extended grounded cathode plate. A stationary crystal of melamine formaldehyde particles is formed in a background of argon plasma inside a confining ring that is isolated from the cathode by a ceramic cover. The stable crystal structure breaks in the core region and transitions to a coexistent state by carefully changing the confining potential, thereby modifying the sheath structure. The transition is confirmed by evaluating the variation in different characteristic parameters such as the pair correlation function, local bond order parameter, and dust kinetic temperature as a function of confining bias potential. It is found that melting in the core is due to the onset of dust fluctuations in the layers beneath the topmost layer, which grow in amplitude as the confining bias potential is reduced below a threshold value. The present technique of changing confinement provides a unique feature to study structural transitions of plasma crystals without affecting the overall plasma parameters. Published by the American Physical Society 2024

Heterogeneous Metasurface Empowering Proximate High-Permittivity Ceramic Cover For a 5G Dual-Band Millimeter-Wave Smartphone

Heterogeneous Metasurface Empowering Proximate High-Permittivity Ceramic Cover For a 5G Dual-Band Millimeter-Wave Smartphone

Architecture, Ceramics and Frames. Three case studies in the work of Jorge Barradas

Throughout the history of the azulejo (a Portuguese form of tin-glazed ceramic tile), frames have played a decisive role in the articulation of this element with its architectural support. From the late 1940s onwards, Portuguese artists have felt the influence of the International Modern Movement, especially via the Brazilian model and its solutions for integrating azulejos within the new architectural forms. This movement translated into new buildings and equipments, promoting the interaction between architects and artists. Moreover, it led to the renovation of Portuguese ceramic coverings, prompted by the emergence of a new generation of artists strongly influenced by Jorge Barradas.&#x0D; The present article aims to examine three ceramic coverings by Jorge Barradas, focusing on their frames and their articulation with the architecture. The first azulejo covering is the so-called Atlântico Palace, the headquarters of a banking institution in Oporto (1950); the second is located at the Parish Church of Nossa Senhora de Fátima, in Parede, Cascais (1953); the third one is at the Lisbon’s Palace of Justice (1969).

Research on the function failure of accelerometer servo circuit caused by hydrolysis and corrosion

This paper studied the function failure of a quartz flexible accelerometer servo circuit manufactured by a thick-film hybrid integrated process. The circuit adopts the epoxy glue bonding process of the metal shell and the ceramic cover plate to encapsulate, and it is a non-airtight package. After the circuit is powered on, the quiescent current output is abnormal, and the DC voltage output is constant high potential, the acceleration detection function cannot be realized. In response to this phenomenon, the fault tree method is used to locate the failure location, and the fault is located at the abnormal function of the differential capacitor voltage converter chip. Using microscopic analysis and characterization methods, it can be seen that the hydrolysis and corrosion of the surface of differential capacitance-to-voltage converter chip causes leakage in the active area inside the chip, leads to the function failure of the circuit. The above research is of great significance to the design, storage and application of non-hermetic hybrid integrated circuits.

Effect of mixed-shaped silica sol abrasives on surface roughness and material removal rate of zirconia ceramic cover

Zirconia ceramic, as mobile phone body-materials, will become increasingly important with the coming of 5G communication technology. Surface quality and material removal rate of zirconia ceramic cover are vital factors to determine its wide application. Therefore, mixed-shaped silica sol abrasives were prepared by ion connecting-inducting method and applied to achieve a good surface quality and a high material removal rate on zirconia ceramic cover by using chemical mechanical polishing (CMP). Mixed-shaped silica sol abrasives contained spherical and beaded shapes were measured by scanning electron microscopy (SEM). Si–O–Al bonds were formed in the mixed-shaped silica sol abrasives and were proved by X-ray photoelectron spectroscopy (XPS). Results of CMP tests showed that zirconia ceramic cover obtained a low surface roughness of 1.824 nm and an efficient material removal rate of 0.33 μm/h. Compared with traditional spherical silica sol abrasives, the polishing rate of mixed-shaped silica sol abrasives increased by 242%. Additionally, solid-phase chemical reactions happened to formed ZrSiO4, ZrAl2Si2O9 in the CMP process. Moreover, friction coefficient was tested and polishing mechanism had been explored by a contact-friction model in this work.

Coroas cerâmicas bi-layers: Uma revisão de literatura sobre tipos de cerâmicas, processamento cerâmico e tensão residual

INTRODUÇÃO: O uso de materiais cerâmicos como estratégia restauradora enfrenta algumas problemáticas, como interferências entre a porcelana e zircônia, sendo a primeira utilizada como cerâmica de cobertura e a segunda como infraestrutura ou coping. OBJETIVO: revisar a literatura sobre coroas cerâmicas bi-layer, através dos tipos de cerâmicas, processamento cerâmico e tensão residual. METODOLOGIA: As bases de dados para esta revisão foram Bireme, Pubmed, Scielo e Bibliotecas Virtuais. As palavras-chaves foram buscadas no Mesh, quanto aos critérios de inclusão são Estudos, Laboratoriais e Clínicos, Revisão Sistemática e Metanálise, artigos científicos e literatura específica sobre o tema, literatura em inglês e português. Já os critérios de exclusão foram carta ao editor, caso clínico e artigo de opinião, literaturas que não abordasse o tema em estudo e artigos que abordem outras cerâmicas odontológicas. A literatura e os artigos foram selecionados por meio de resumos e abstracts. CONSIDERAÇÕES FINAIS: Tensão residual em coroas cerâmicas bi-layers, com infra-estrutura em zircônia e cobertura em porcelana, ocorrem pela ação de diversos fatores como coeficiente de expansão térmica, velocidade de resfriamento, processamento e espessura da cerâmica de cobertura.

Extending service life of hall thrusters: recent progress and future challenges

Hall thrusters are widely applied to space propulsion missions because of characteristics such as high specific impulse, great thrust-to-power ratio, high efficiency, and simple structure. Because the scope of space missions using Hall thrusters has expanded, a higher total impulse is required to extend a north–south station-keeping mission to an orbit transfer mission, requiring Hall thrusters with improved lifetimes. Existing research shows that improving the anti-sputtering capacity of the discharge channel and significantly reducing the ion energy and flux bombardment on the wall of the discharge channel are the best measures to improve the lifetime of Hall thrusters. This study summarizes the lifetime restraining factors of Hall thrusters and analyzes the magnetic shielding technology, wall-less technology, aft-magnetic technology, and cylindrical Hall thruster technology to reduce ion energy and flux bombardment on the discharge-channel wall, adopting low-sputtering yield materials to reduce the wall erosion rate, which can improve the lifetime of Hall thrusters. This paper also identifies the limitations of each technology, such as the erosion of magnetic poles (MS) and ceramic cover plates (CHT), larger plume divergence angle (wall-less), hard-to-select aft-magnetic degree (aft-magnetic technology), low compactness, and great porosity (graphite material), providing a reference for further research.

Periodontal and prosthetic outcomes on teeth prepared with biologically oriented preparation technique: a 4-year follow-up prospective clinical study

PurposeTo evaluate the clinicaland biological behavior of full coverage restorations on teeth prepared without finish line during a 4-year follow-up. MethodsThis prospective study included 149 teeth treated using biologically oriented preparation technique (BOPT). The sample (149 teeth) was divided into two groups: Seventy four teeth restored with crowns, and 75 teeth supporting fixed partial dentures (FPD). Restorations were fabricated with zirconium oxide cores and ceramic coverings. Patients attended regular annual check-ups when probe depth, presence of inflammation with bleeding on probing, presence of plaque, gingival thickness, marginal stability, biological or mechanical complications, and the patient’s level of satisfaction were registered over a 4-year follow-up. ResultsAfter the 4-year follow-up, 2.1% of teeth underwent increases in probing depth; 12% of the sample presented inflammation and bleeding on probing; 20% of the restored teeth presented plaque; gingival thickening increased a 32.5%; 98.6% of teeth presented marginal stability; the restoration survival rate was 96.6%, with 2% of biological complications and 1.4% of mechanical complications. General satisfaction score was 80.73. ConclusionsRestorations placed on teeth prepared using BOPT present good periodontal behavior, increase of gingival thickening, and marginal stability over a 4-year follow-up. High survival rates after 4 years show that the technique produces predictable outcomes. Clinical significanceThe BOPT technique is a good treatment option in cases where replacement of an old restoration is required; presenting good periodontal behavior, gingival thickening, and marginal stability.

Assembly of Ceramic Coverings on Gypsum Surfaces

Ceramic claddings in the buildings are often tiled on gypsum surfaces, which mainly consist of plasters made of ready dry mixes and walls made of gypsum blocks. One should know about their specific properties, such as absorbency, smoothness and lack of chemical bonding with cement based adhesive mortars. This paper discusses the subject of assembly of ceramic claddings on such substrates and shows examples of damages caused by executive errors. The first part of the paper describes methods of preparing the surface before assembly of ceramic claddings, with particular emphasis on the proper surface priming. The principles of choosing the right mortar for tiling works are also presented. In the second part of the paper, examples of assembly errors are presented, as a result of which the ceramic claddings become detached from the gypsum surfaces. The results of measurements and observations have been described and the reasons for failure of wall claddings have been given.

The application of ceramic stove cover and loading distance to the performance of water boiling system

Conventional gas stove (CGS) used in the water boiling system (WBS) is quite inefficient if the mechanism is not considered. In the present research, an assessment has been performed to a CGS by applying a ceramic stove cover (CSC) and also investigated the optimum distance between CSC and the loading to obtain very best efficiency of a CGS. Several parameters used to investigate the CGS’s performance such as water temperature, heating value of the fuel and temperature of CSC have been used in reference to the definition of efficiency. In this study the distance between CSC and the loading is varied by 1 mm to 7 mm by increment of 1 mm. The results show that at a distance of 4 mm, the performance of a CGS in a certain fuel rate of 12.5 cc/s increase significantly indicated by the best efficiency of 46.4 %. It is because of an optimum condition is accomplished simultaneously in heat transfer processes such convection and radiation in the WBS. Although the fuel rate itself have an influence to the flame structure heating the loading, however, the used of ceramic cover have an effect to the exchange between fresh air and flue gas to the combustion process.

An increase in bed temperature on gasification of dual reactor fluidized bed

One of the main issues using biomass as fuel in air gasification is the dilution of its product gas by the nitrogen in the air. A dual reactor fluidized bed (DRFB) overcomes this problem in which the gasification and combustion reactions are decoupled and conducted in two separate fluidized bed reactors connected by circulating bed material. The DFRB unit made of 304 stainless steel pipe with a height of 100 and 150 cm, and inner diameters (i.d.) of 15.2 and 5.1 cm for gasifier and combustor respectively. The rice husk as fuel and quartz sand as bed material having the same size of 0.4 - 0.6 mm were applied in this investigation. Since the gasification process is an endothermic reaction, gasification temperatures are varied at 600°C to 700°C while combustion reactor were kept at 600°C using the electric heaters enclosed in ceramic cover. The superficial gas velocity in this study was kept constant at 17 m/s using the external air volumetric flux of the blower flow entering the DRFB loop. Gas gasification samples are then examined by gas chromatography to determine syngas content (CO, CH4 and H2). The test results showed that by the increasing temperature of the gasification reactor there was an increase in syngas especially CO gas conentration. The temperature increases in the gasification reactor (600°C, 650°C, 700°C) is able to increase the endothermic reaction in the gasification process which is dominated by CO gas production. The syngas efficiency was found to increase from 40.95% to 43.77%.as the temperature of the gasification reactor increased.

The Effect of Lithium Disilicate Opacity on Polymerization of a Dual-Cured Resin Cement.

The aim of this study was to evaluate the influence of different levels of opacity of the lithium disilicate framework upon polymerization of dual-cured resin cement. Four ceramic discs were used, one for each opacity framework covered by their respective ceramic veneering, and a cement group without a ceramic cover. The degree of conversion for each resin cement was estimated using the Knoop microhardness test. The group with the highest opacity showed the lowest hardness score at baseline. The study concluded that the opacity level of lithium disilicate framework could influence the degree of polymerization of a dual-cured resin cement.

Peningkatan Efisiensi Sistem Pemanasan dengan Penambahan Grid pada Perforated Burner

Efficiency of a domestic gas stove depend on the kind of burner material and its configuration. In this study, a material in the form of a grid has been inserted into combustion chamber to modify flame characteristics. Grids made from stainless steel with different thickness were inserted between burner and loading. Ceramic stove cover was used to prevent heat release from flame. To develop the term of efficiency of the system, many parameters were measured as energy from fuel, cover temperature and water temperature. The results show that in certain fuel rate of 45 l/h, a heating system with a grid of 5 mm has maximum efficiency of 58,8 % indicate a differentiation of 5 % higher compared to the heating system with no grid. Grid material absorbs energy from combustion process, keep the temperature in the combustion chamber remain high also induce turbulence upstream the grid surface causing fuel-air mixing improved.

Control de la obra terminada: inspección final de calidad en un proyecto de interés social

Social housing is often associated to buildings of low quality level; however it is important to have objective elements to verify this question so the control of thefinished work constitutes a good quality measure. This study presents and evaluates the problems found in a typical social housing project funded under the Brazilianhousing program Minha Casa, Minha Vida, built in Sao Leopoldo, a city on southern Brazil. The work was monitored during the last six months of its final phase ofexecution. The inspection reports of the completed work were analyzed and observations were proposed directly at the construction site. The first owner’s inspectionreached about 64% failure. In some cases, it took four attempts to finally obtain the owner’s acceptance. Analyzing data collected we concluded that windows,doors and ceramic coverings were a major source of complaints, reaching more than 77% of the problems pointed out in the inspections. The failures detected in thisproject were caused by problems related to workmanship, lack of quality of materials and the components used, as well as insufficient quality checks of the servicesperformed. We observed the need to improve quality controls although the building firm had a certification by PBQP-H (a Brazilian certify similar to the ISO 9000).The correct procedures were defined on quality documentation but they were not followed. Rev. ing. constr. [online]. 2015, vol.30, n.2, pp. 147-153. ISSN 0718-5073. http://dx.doi.org/10.4067/S0718-50732015000200006

Analysis of Flexural Strength of Ceramics Based on Zirconia Stabilized by Yttria with Ceramic Cover

The aim of this study was to analyze the flexural strength of ceramics based on yttria-stabilized zirconia ( Y-TZP) , used in the manufacture of dental prostheses infrastructure with different types of coating ceramics. The rectangular samples measuring 18mm x 4mm x 1.2 mm were divided into groups (n = 10): G1 = control Y-TZP, G2= Y-TZP + sintered feldspathic ceramic and G3= Y-TZP + pressable feldspathic ceramic and submitted to assay of three points with a speed of 0.5 mm / min. Compared to the control group (G1), the group that showed the greatest resistance to bending was the G2, however, not significant relative to G3. No group provided the infrastructure fracture. It was observed by means of the methodology applied to all groups are suitable for use in dental prostheses.

Jarak Optimum Panci Terhadap Selubung Pada Efisiensi Sistem Pemanasan Air

Energy conservation from fossil fuel is urging to be implemented recently, including conservation in a conventional gas stove (CGS). Considering the mechanism of a CGS, there are many prospects to enhance its performance. In this study, efficiency of a CGS has been investigated by varying the gap between pan and stove cover. Many parameters were measured as energy from fuel, cover temperature and water temperature to develop efficiency equation of heating system. Ceramic cover was used to prevent heat release from flame. Gaps between pan and stove cover were varied in 1 mm to 7 mm with increment of 1 mm. The results showed that in certain fuel rate of 45 l/h, the gap of 4 mm indicated the highest efficiency of 46.4 % due to the optimum condition was achieved simultaneous in convection and radiation heat transfer processes of the heating system.

Research on the electro-elastic properties of the 2-1-3 (a revised version of 1-3-2) piezoelectric composite by finite element method

For the applications of underwater acoustics and ultrasonics, the 1-3 piezoelectric composite has proven to be useful material given its attractive performance. As a special modified version of 1-3 composite, the 1-3-2 piezoelectric composite which is composed of 1-3 composite and a ceramic base layer has been studied a lot recently for getting greater stability than 1-3 composite. But there still exist shortcomings caused by limitations in the manufacturing process of both 1-3 and 1-3-2 piezoelectric composites. In this article, a 2-1-3 composite that consists of 1-3 composite and a ceramic cover layer instead of the ceramic base layer for 1-3-2 composite is proposed to loosen the fineness requirement of 1-3 or 1-3-2 composites in the manufacturing process. The finite element method (FEM) has been adopted to analyze the dependence of electric-elastic properties (the longitudinal velocity and thickness electromechanical coupling coefficient) of 1-3, 1-3-2, and 2-1-3 composites on the aspect ratio α (the ratio of the lateral periodicity of PZT rods to the thickness of composite). The results of the 2-1-3 composite with soft matrix show great improvement in loosening the fineness requirement of the manufacturing. Typically, the fineness of 30%-volume faction 2-1-3 composite can be reduced to 2.54% of that of 1-3-2 composite. Hence, the 2-1-3 composite offers greater feasibility for the design of various sensing materials. POLYM. COMPOS., 37:2384–2395, 2016. © 2015 Society of Plastics Engineers

Design and experimental studies on ceramic port cover for dual pulse motor

Material and definition of dome-shaped ceramic port cover contour is presented. Two types of ceramic port covers with equal thickness and variable thickness structures are proposed. A group of cold-flow tests was carried out on a reusable dual pulse motor in which the performances of different port covers including sealing, first-pulse pressure bearing and second-pulse broken pressure were experimentally studied. A solid dual pulse motor for hot-firing test was designed, manufactured and statically tested. The feasibility of proposed bulkhead with ceramic port cover employed on actual solid dual pulse motor was proved. It is found that dome-shaped port cover made from machinable glass ceramic withstands a high pressure on its convex side, but is prone to fragmentation while imposing a reasonably low pressure on its concave side. The peripherally thickened port cover that is more robust in machining and assembly process is recommended. Grooves milled on the port cover induce fragmentation and are helpful to produce regular broken aperture shape. The bulkhead assembly consists of retaining ring, port cover and supporting ring can well fulfill the requirements of port cover in fixing, preloading and sealing. The broken fragments are less likely to damage the insulation structures of the combustion chamber and the nozzle unit which had been validated in the test.