scholarly journals STRUCTURAL AND MECHANICAL PROPERTIES OF A COMPOSITE MATERIAL BASED ON PARTIALLY STABILIZED ZIRCONIUM DIOXIDE DOPED WITH MAGNESIUM ALUMINATE SPINEL

2021 ◽  
pp. 78-85
Author(s):  
A.V. Sokolov ◽  
◽  
G.I. Deynega ◽  
N.A. Kuzmina ◽  
I.G. Kuzmina ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Zirconium Dioxide ◽  
Chemical Resistance ◽  
Raw Materials ◽  
Ceramic Materials ◽  
High Tech ◽  
Magnesium Aluminate Spinel ◽  
Temperature Changes ◽  
Wide Range ◽  
Stabilized Zirconium Dioxide

Ceramic materials based on zirconia (ZrO2) are high-tech raw materials for structural products used in various fields of technology. ZrO2 has a wide range of application due to its unique strength characteristics, chemical resistance and fire resistance. However, the disadvantage of zirconium ceramics is low resistance to thermal shock, which limits its use in products functioning in conditions of frequent temperature changes. In this paper, we consider the possibility of increasing the resistance to thermal shock of ceramics based on zirconium dioxide, due to the introduction of an aluminum-magnesium spinel additive (MgAl2O4).

Ceramic Composition Material with Mullite Crystals Obtained from the Clayy Raw Material of Yakutia

2020 ◽  
Vol 992 ◽  
pp. 253-258
Author(s):  
M.P. Lebedev ◽  
V.N. Tagrov ◽  
E.S. Lukin
Keyword(s):  
Building Materials ◽  
Raw Materials ◽  
Practical Interest ◽  
Physical And Mechanical Properties ◽  
Ceramic Materials ◽  
Strength Properties ◽  
Raw Material ◽  
Composition Material ◽  
Material Base ◽  
Wide Range

The article deals with the manufacture of modern structural ceramic materials from clay and loam deposits of the Republic of Sakha (Yakutia). The importance and relevance of the development of the production of building materials from local raw materials is emphasized, since this will certainly affect the effectiveness of the construction complex as a whole. The successful development of the construction complex is capable of not only stimulating growth in all sectors of the economy, but also contributes to solving the most pressing social problems. Today, Yakutia has huge reserves of mineral raw materials for the production of a wide range of building materials and products. Of practical interest are wall materials made from clay soils. Given the features of the region’s raw material base, this work focuses on additional processing of traditional material. Controlling the complex physicochemical and structural-mechanical transformations that occur during heat treatment, a methodology has been developed for creating a composite material that will allow competitive innovative materials with enhanced strength properties to be produced with a reinforcing element with a glassy phase matrix of mullite crystals. The fabricated samples have a wide range of physical and mechanical properties and allow using it as a high-quality structural building ceramics, as well as industrial floor technical tile.

Developing of Honeycomb Shaped Cordierite Ceramic from Indigenous Raw Materials and its Characterization

2011 ◽  
Vol 264-265 ◽  
pp. 597-601 ◽  
Author(s):  
S. Begum ◽  
Halina Misran ◽  
A. Aminuddin
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Raw Materials ◽  
Holding Time ◽  
Peak Temperature ◽  
Particulate Filter ◽  
High Porosity ◽  
Cordierite Ceramic ◽  
Wide Range ◽  
Shock Resistance

Cordierite ceramic of chemical composition 2MgO-2Al2O3-5SiO2 has low value of thermal expansion, excellent thermal shock resistance, high porosity and high strength. The exhibited properties resulted wide range of industrial applications, especially in the catalytic converter, kiln furniture, diesel particulate filter and high frequency insulator. It occurs rarely in nature and its formulation from the indigenous raw materials is sensitive to the peak sintering temperature and holding time. Both the parameters are again affected on the source of raw materials. Hence optimization of peak temperature and holding time is crucial for each source of raw materials. In this paper three indigenous raw materials, clay, kaolin and talc were taken and mixed with different dopants. The prepared powder batch was sintered at different peak temperature and holding time. Among the three indigenous raw materials kaolin was found to be most suitable to formulate cordierite. The peak temperature was varied within the range of 1340°C -1400°C and the holding time was considered from 30 minutes to 90 minutes. Both the parameters had significant influence on the production of cordierite. The percent of cordierite formation was affected with both the variation of holding time and peak temperature. Tough thermal shock resistance was not influenced by any of the parameters, but the influence on the porosity was quite significant. The green body was also prepared from calcined powder batch and was sintered at different peak temperature. Calcination did not exhibit any affect on cordierite formulation.

scholarly journals Effect of bentonite addition on some properties of porcelain

2018 ◽  
Vol 25 (1) ◽  
pp. 84-99 ◽  
Author(s):  
Shihab A. Zaidan ◽  
Shahad Sarmed Abdull-Razzak
Keyword(s):  
Raw Materials ◽  
Ceramic Materials ◽  
Potassium Feldspar ◽  
X Ray Diffraction ◽  
Mechanical Mixing ◽  
Weight Percentage ◽  
Wide Range ◽  
Amorphous Glass ◽  
Loss Of Mass ◽  
Sodium Feldspar

Porcelain is one of the most important ceramic materials with a wide range of traditional and technical applications. Since most mixtures of porcelain have a high sintering temperature, bentonite has been added in this research to improve the characteristics of sintering and burning. The porcelain mixture consisted of the following Iraqi raw materials: 30% wt kaolin, 30 wt% non-plastic clay (grog), 10% wt sodium feldspar, 10 wt% potassium feldspar and 20 wt% flint. After the mechanical mixing process and transfer the powder mixture to the slurry by adding distilled water, then different weight percentage of the sodium bentonite(0, 2.5, 5, 7.5 and 10) wt% was added. The specimens were prepared by using the solid casting method, and after the drying process, the specimens were burned at1100 oC. The results of x-ray diffraction showed that bentonite reduced the crystallization of the main ceramic phases (mullite, quartz), which stimulates the appearance of amorphous glass phases. Also, the loss of mass on ignition increased when the addition of bentonite from 5.66% to 8.2%. There was also a great convergence between the granules of porcelain when adding bentonite and thus increase the shrinkage of the dimensions from 9.33% to 12.37 %. This led to increasing the bulk density from 1.97 g/cm3 to 2.67 g/cm3 at firing temperature 1100oC, and the porosity was decreased from 17.1% to 1.44%. Diametrical strength and flexural strength (bending) increased with bentonite (14.88 to 34.46MPa), (6.2 to 8.65 MPa), respectively.  

Improvement of Thermal Shock Resistance Performance of High Alumina Ceramic Filter Support

2013 ◽  
Vol 750-752 ◽  
pp. 525-528
Author(s):  
Yue Chao Tian ◽  
Xi Liu ◽  
Hui Tang ◽  
Jing Long Bu ◽  
Dong Mei Zhao ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Bending Strength ◽  
Raw Materials ◽  
Ceramic Materials ◽  
Raw Material ◽  
Ceramic Filter ◽  
High Alumina ◽  
Gas Cleaning ◽  
Shock Resistance

Mullite-corundum multiphase ceramic materials were prepared at 1400°C for 2h with bauxite chamotte and clay clinker as raw material (size<74 μm), molded at pressure of 50 MPa. Effect of raw materials composition on sintering and themal shock resistance of composite were researched by measurements of apparent porosity, bending strength，thermal shock resistance and thermal expansion rates, and analysed by XRD and SEM. The results showed that the best weigh percentage of raw materials with better sintering and themal shock resistance are bauxite chamotte 50 wt%, clay clinker 50wt% for mullite-corundum multiphase ceramic materials. The test results for high temperature gas cleaning dust removal technology development and the application of the composite ceramic material has important application value.

Microstructural characterization of laser-melted/roller-quenched dicalcium silicate

1988 ◽  
Vol 46 ◽  
pp. 582-583
Author(s):  
C. J. Chan ◽  
K. R. Venkatachari ◽  
W. M. Kriven ◽  
J. F. Young
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Shape Change ◽  
Microstructural Characterization ◽  
Particle Size Effect ◽  
Dicalcium Silicate ◽  
Laser Melting ◽  
Uniform Size ◽  
Cell Shape Change ◽  
Wide Range

Dicalcium silicate (Ca2SiO4) is a major component of Portland cement. It has also been investigated as a potential transformation toughener alternative to zirconia. It has five polymorphs: α, α'H, α'L, β and γ. Of interest is the β-to-γ transformation on cooling at about 490°C. This transformation, accompanied by a 12% volume increase and a 4.6° unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation in zirconia. Due to the processing methods used, previous studies into the particle size effect were limited by a wide range of particle size distribution. In an attempt to obtain a more uniform size, a fast quench rate involving a laser-melting/roller-quenching technique was investigated.The laser-melting/roller-quenching experiment used precompacted bars of stoichiometric γ-Ca2SiO4 powder, which were synthesized from AR grade CaCO3 and SiO2xH2O. The raw materials were mixed by conventional ceramic processing techniques, and sintered at 1450°C. The dusted γ-Ca2SiO4 powder was uniaxially pressed into 0.4 cm x 0.4 cm x 4 cm bars under 34 MPa and cold isostatically pressed under 172 MPa. The γ-Ca2SiO4 bars were melted by a 10 KW-CO2 laser.

Comparative Effects of High-Tech Visual Scene Displays and Low-Tech Isolated Picture Symbols on Engagement From Students With Multiple Disabilities

2019 ◽  
Vol 50 (4) ◽  
pp. 693-702 ◽  
Author(s):  
Christine Holyfield ◽  
Sydney Brooks ◽  
Allison Schluterman
Keyword(s):  
Language Learning ◽  
Augmentative And Alternative Communication ◽  
Visual Analysis ◽  
Multiple Disabilities ◽  
Visual Scene ◽  
Future Research ◽  
High Tech ◽  
Single Subject ◽  
Wide Range ◽  
The Difference

Purpose Augmentative and alternative communication (AAC) is an intervention approach that can promote communication and language in children with multiple disabilities who are beginning communicators. While a wide range of AAC technologies are available, little is known about the comparative effects of specific technology options. Given that engagement can be low for beginning communicators with multiple disabilities, the current study provides initial information about the comparative effects of 2 AAC technology options—high-tech visual scene displays (VSDs) and low-tech isolated picture symbols—on engagement. Method Three elementary-age beginning communicators with multiple disabilities participated. The study used a single-subject, alternating treatment design with each technology serving as a condition. Participants interacted with their school speech-language pathologists using each of the 2 technologies across 5 sessions in a block randomized order. Results According to visual analysis and nonoverlap of all pairs calculations, all 3 participants demonstrated more engagement with the high-tech VSDs than the low-tech isolated picture symbols as measured by their seconds of gaze toward each technology option. Despite the difference in engagement observed, there was no clear difference across the 2 conditions in engagement toward the communication partner or use of the AAC. Conclusions Clinicians can consider measuring engagement when evaluating AAC technology options for children with multiple disabilities and should consider evaluating high-tech VSDs as 1 technology option for them. Future research must explore the extent to which differences in engagement to particular AAC technologies result in differences in communication and language learning over time as might be expected.

High-tech methods for processing meat raw materials

2020 ◽  
pp. 20-24
Author(s):  
M.G. Baryshev ◽  
A.A. Zaporizhzhya ◽  
G.I. Kasyanov
Keyword(s):  
Raw Materials ◽  
High Tech

Gluten-Free Dry Mixtures with Rice and Amaranth for Children over Three Years Old with Gluten Intolerance

Food Industry ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 23-31
Author(s):  
Sergey Urubkov ◽  
Svetlana Khovanskaya ◽  
Ekaterina Pyrieva ◽  
Olga Georgieva ◽  
Stanislav Smirnov
Keyword(s):  
Celiac Disease ◽  
Treatment Effectiveness ◽  
Raw Materials ◽  
Calculated Data ◽  
Limited Range ◽  
Gluten Free ◽  
Fruit And Vegetable ◽  
Organoleptic Evaluation ◽  
Free Products ◽  
Wide Range

Diet therapy is one of the main approaches to the treatment of a wide range of diseases of the digestive system. The treatment effectiveness of celiac disease depends on how strictly the patient adheres to a gluten-free diet. It is often disrupted due to the limited range of recommended foods and dishes, especially for children who are particularly sensitive to dietary restrictions. In this case, the development of new types of specialized gluten-free products is relevant, allowing to expand the diet both in terms of nutritional value and taste diversity. This study concerns the recipe developments of dry gluten-free mixtures using rice and amaranth with the inclusion of fruit and vegetable and berry raw materials intended for the nutrition of children over three years old suffering from celiac disease. When developing the recipes, researchers used various combinations of rice and amaranth flour, as well as fruit and vegetable powders. The rice flour composition varied in the range from 15 to 75%; amaranth – from 15 to 45%; fruit and vegetable and berry powders – up to 10%. The finished product was gluten-free cookies, muffins, pancakes made of rice and amaranth. Organoleptic evaluation showed that the studied samples of gluten-free cookies have high quality characteristics, have a pleasant taste and aroma. According to the calculated data, specialized gluten-free dry mixtures intended for children over three years with celiac disease can serve as an important source of: vegetable carbohydrates – from 26.81 to 55.19 g / 100g of finished products; protein – from 4.06 to 11.82 g/100g of finished products; dietary fiber – from 3.82 to 6.36 g/100g of finished products; and energy – from 158.12 to 333.96 kcal/100g of finished products) The developed recipess of gluten-free products can help to provide children with an adequate amount of nutrients and energy.

Safety assessment of biological raw materials in the system of medicines quality assurance

2020 ◽  
pp. 63-72
Author(s):  
Yu. Olefir ◽  
E. Sakanyan ◽  
I. Osipova ◽  
V. Dobrynin ◽  
M. Smirnova ◽  
...  
Keyword(s):  
Raw Materials ◽  
State Level ◽  
The State ◽  
Spongiform Encephalopathy ◽  
Safety Standards ◽  
Wide Range ◽  
The Russian Federation ◽  
Key Aspects ◽  
First Time ◽  
Medicines Quality

The entry of a wide range of biotechnological products into the pharmaceutical market calls for rein-forcement of the quality, efficacy and safety standards at the state level. The following general monographs have been elaborated for the first time to be included into the State Pharmacopoeia of the Russian Federation, XIV edition: "Viral safety" and "Reduction of the risk of transmitting animal spongiform encephalopathy via medicinal products". These general monographs were elaborated taking into account the requirements of foreign pharmacopoeias and the WHO recommendations. The present paper summarises the key aspects of the monographs.

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