scholarly journals Relaxation of ceramic tile stresses generated by fast drying: a kinetic model

2018 ◽  
Author(s):  
J. L. Amorós ◽  
V. Cantavella ◽  
E. Blasco
Keyword(s):  
Mechanical Properties ◽  
Stress Relaxation ◽  
Kinetic Model ◽  
Moisture Content ◽  
Mechanical Strength ◽  
Ceramic Tile ◽  
Drying Process ◽  
Ceramic Tiles ◽  
Relaxation Kinetic ◽  
Dry Conditions

Abstract Unfired tile mechanical properties are very important in the ceramic tile manufacturing process. Inadequate mechanical properties lead to rejects (both in unfired and fired tiles). Unfired tile mechanical strength changes significantly after the tiles exit the industrial dryer. This behaviour can be explained by assuming that the fast-drying process generates stresses in the tile, which subsequently relax. A kinetic model has been derived, based on Maxwell’s viscoelastic elements, which explains the development of dried tile mechanical strength. This increases asymptotically when the dried tiles are stored in dry conditions. However, if tiles adsorb humidity (upon exiting the dryer), tile mechanical strength rises and then decreases. This is the result of two opposing phenomena: stress relaxation raises mechanical strength while the concurrent rise in moisture content lowers mechanical strength. The developed model successfully describes this joint mechanical behaviour. Keywords: ceramic tiles, fast drying, stress relaxation, kinetic model

Glass Transition Temperature, Mechanical Properties of Rice and their Relationships with Milling Quality

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Kobra Tajaddodi Talab ◽  
Mohd. Nordin Ibrahim ◽  
Sergey Spotar ◽  
Rosnita A. Talib ◽  
Kharidah Muhammad
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Moisture Content ◽  
Bending Strength ◽  
Bending Test ◽  
Transition Line ◽  
Transition Temperatures ◽  
Drying Process ◽  
Glass Transition Temperatures ◽  
Grain Moisture

Abstract Glass transition temperatures (Tg) of MR219 rice variety were measured by differential scanning calorimeter (DSC). State diagram was developed and used to evaluate drying process in this study. Glass transition temperatures range of 9.65- 61.79°C were observed for gains with moisture content of 26.8 – 7.4% (w.b.). For mechanical properties and milling test, statistical analysis was performed by using a two factor experiment in completely randomized design (CRD). Two selected factors were drying temperatures at 5 levels (40, 45, 50, 55, and 60°C) and final moisture content (FMC) at 4 levels (10-10.5, 11-11.5, 12-12.5 and 13-13.5%). Three–point bending test was applied to measure the mechanical properties of rice kernel. Generally, bending strength, apparent modulus of elasticity and fracture energy of brown rice kernel increased with decreasing the grain moisture content. Maximum bending strength was 35.69 and 33.64 MPa for 55, and 60°C, respectively. All samples that were dried at 55 and 60°C experienced to go through the glass transition line after reaching their temperature to the room temperature at the end of drying process. The effect of drying temperature, paddy FMC and their interactions on whole kernel percentage (WKP) and mechanical properties were significant (α = 0.05). An inverse relationship was observed between WKP and the percentage of strong kernels for all treatments.

scholarly journals Moisture content and mechanical properties reduction of hard capsules upon prolong drying process

2021 ◽  
Vol 1092 (1) ◽  
pp. 012057
Author(s):  
Mohd Aiman Hamdan ◽  
Nur Hikmah Sulaiman ◽  
Khairatun Najwa Mohd Amin ◽  
Fatmawati Adam
Keyword(s):  
Mechanical Properties ◽  
Moisture Content ◽  
Drying Process

Mechanical Properties of Hulless Barley Stem with Different Moisture Contents

2019 ◽  
Vol 15 (1-2) ◽  
Author(s):  
Jia-hui Chen ◽  
Nan Zhao ◽  
Nan Fu ◽  
Dong Li ◽  
Li-jun Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stress Relaxation ◽  
Moisture Content ◽  
Loss Modulus ◽  
Maxwell Model ◽  
Creep Tests ◽  
Hulless Barley ◽  
Dynamic Mechanical ◽  
Moisture Contents ◽  
Study Results

AbstractMechanical properties of hulless barley stems with different moisture contents (10.23%–43.14%) were investigated by using temperature sweep, frequency sweep, stress relaxation and creep tests of dynamic mechanical analyzer (DMA) in this study. Results showed a significant dependence of storage modulus, loss modulus and tan delta on moisture content. The data from stress relaxation and creep was fitted by using generalized Maxwell model and Burgers model. 5-element Maxwell model was better for describing relaxation behaviors of hulless barely stem compared with the 3-element Maxwell model. The peak values of loss modulus and tan delta both occurred at a low temperature when moisture content increased. The dynamic mechanical properties can provide useful information for the harvesting and processing of huless barely stem.

scholarly journals Coffee Husk as Feldspar Substitute in the Manufacture of Enameled Ceramic Tile

2020 ◽  
Vol 30 (2) ◽  
pp. 21-30
Author(s):  
Alejandra Sarabia-Guarín ◽  
Rosa Patricia Ramírez-Delgado ◽  
Jorge Sánchez-Molina
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Surface Quality ◽  
Working Conditions ◽  
Apparent Density ◽  
Ceramic Tile ◽  
Physical And Mechanical Properties ◽  
Ceramic Tiles ◽  
Coffee Husk ◽  
Firing Shrinkage

This study researches the effect of adding coffee husk (CH) and coffee husk ash (CHA) as partial feldspar substitutes to the manufacture of enameled ceramic tiles. Clays and other paste additives were characterized using XRD and XRF. The designed prototypes were pressed, dried, and fired at 1,120 °C. The physical (drying and firing shrinkage, apparent density, water absorption) and mechanical (flexion resistance) properties were evaluated and compared with standard fired specimens. Although the physical and mechanical properties of the specimens with 5 and 10 % CH and CHA make them suitable for the manufacture of BIIb ceramic tiles, it was concluded that CH and CHA under the working conditions do not replace feldspar in the preparation of enameled ceramic tiles due to surface quality defects.

scholarly journals Effect of waste glass powder on physico-mechanical properties of ceramic tiles

2012 ◽  
Vol 24 (2) ◽  
pp. 169-180 ◽  
Author(s):  
Sonjida Mustafi ◽  
Mainul Ahsan ◽  
A Hamid Dewan ◽  
Samina Ahmed ◽  
Nazia Khatun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Key Words ◽  
Bulk Density ◽  
Ceramic Tile ◽  
Glass Powder ◽  
Waste Glass ◽  
Ceramic Tiles ◽  
Waste Glass Powder ◽  
Firing Shrinkage

Key words: Ceramic tile; water absorption; bulk density; firing shrinkage; modulus of ruptureDOI: http://dx.doi.org/10.3329/bjsr.v24i2.10775 Bangladesh J. Sci. Res. 24(2):169-180, 2011 (December) 

Competition between Hydration and Carbonation in Hydraulic Lime and Lime-Pozzolana Mortars

2010 ◽  
Vol 133-134 ◽  
pp. 241-246 ◽  
Author(s):  
Özlem Cizer ◽  
Koen Van Balen ◽  
Dionys Van Gemert
Keyword(s):  
Mechanical Properties ◽  
Moisture Content ◽  
Strength Development ◽  
Strength Gain ◽  
Carbonation Reaction ◽  
Hydraulic Lime ◽  
Pozzolanic Material ◽  
Dry Conditions ◽  
Sufficient Strength

A combined reaction of hydration and carbonation takes place in hydraulic lime and lime-pozzolana mortars. Hydration reactions are the first reaction and carbonation of lime is the complementary reaction in the strength gain. Competition between these two reactions can occur in lime-pozzolana mortars if the pozzolanic material has low reactivity with lime, leading to the consumption of lime by carbonation reaction. The degree and the order of these reactions are strongly influenced by the moisture content. Hydration reactions are enhanced under moist conditions while carbonation is delayed. Curing under dry conditions does not sufficiently increase their strength because the hydration reactions are slowed down or even terminated by the full carbonation of lime in lime-pozzolana mortars. The consequence of this on the mechanical properties of the mortars is remarkable while the same impact is not observed in their porosity. Such mortars require moist conditions to ensure sufficient strength development.

Use of Nepheline-Syenite, Talc and Kaolinitic Clay to Obtain Ceramic Tiles

2010 ◽  
Vol 660-661 ◽  
pp. 675-680 ◽  
Author(s):  
Kênia Oliveira Teixeira ◽  
Sérgio Neves Monteiro ◽  
Carlos Maurício Fontes Vieira
Keyword(s):  
Mechanical Strength ◽  
Ceramic Tile ◽  
Nepheline Syenite ◽  
Linear Shrinkage ◽  
Uniaxial Pressure ◽  
Ceramic Tiles ◽  
Standard Specification ◽  
Three Point Bending ◽  
Kaolinitic Clay ◽  
Density Linear

This work has for objective to obtain vitrified ceramic tiles by adding nepheline-syenite flux and talc to a kaolinitic clay from Campos dos Goytacazes. Specimens were prepared by uniaxial pressure at 30 MPa followed by firing at 1100, 1150 and 1200oC. The fired specimens were submitted to the following tests: bulk density, linear shrinkage, three point bending mechanical strength and water absorption. The microstructure of the ceramic was evaluated by SEM. The results showed that the incorporation of nepheline-syenite and talc significantly enhanced the properties of the clay making it possible to attain the standard specification corresponding to vitrified ceramic tile.

scholarly journals Influence of moisture content on the mechanical properties of selected wood-based composites

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 5503-5513
Author(s):  
Conrad M. Sala ◽  
Eduardo Robles ◽  
Aneta Gumowska ◽  
Anita Wronka ◽  
Grzegorz Kowaluk
Keyword(s):  
Mechanical Properties ◽  
Moisture Content ◽  
Modulus Of Elasticity ◽  
Wood Quality ◽  
Construction Materials ◽  
Modulus Of Rupture ◽  
Slight Reduction ◽  
Furniture Industry ◽  
Different Types ◽  
Dry Conditions

Wood quality depends on many circumstances, as it is sensitive to changing properties, depending on the environment. This work evaluates the influence of moisture content of selected wood-based composites on their basic mechanical properties, i.e., modulus of rupture and modulus of elasticity. The selected panels were divided by application in construction materials and furniture materials, which demand specific conditions during service-life. The increase of moisture content in different types of wood-based panels resulted in a slight reduction of the modulus of rupture and the modulus of elasticity. Boards for use in dry conditions, mainly in the furniture industry, were more sensitive to lowering their modulus of elasticity with higher board moisture content compared with those designed for humid conditions, mainly from the building industry.

scholarly journals Impact of Moisture Content on the Dynamic Failure Energy Dissipation Characteristics of Sandstone

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Aihong Lu ◽  
Shanchao Hu ◽  
Ming Li ◽  
Tianzhu Duan ◽  
Bing Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Elastic Modulus ◽  
Energy Dissipation ◽  
Surface Energy ◽  
Moisture Content ◽  
Rock Masses ◽  
Moisture Contents ◽  
Dry Conditions ◽  
Moisture Conditions

Rockburst frequently occurs in deep underground engineering, which poses a threat to safety and causes economic losses. Water injection into surrounding rock masses is an effective method for preventing rockburst, and the moisture content of rocks is significant for assessing the probability of rockburst. However, the majority of studies focus on the relationship between the macromechanical properties of rock masses under static loads and the moisture content of rock masses and seldom explore the impact of moisture variation (under dynamic loads) on the mechanical properties and energy dissipation. In this paper, the mechanical properties and energy dissipation of sandstone with different moisture contents have been experimentally investigated by the split Hopkinson pressure bar (SHPB) test. The test results indicate that the peak strength, dynamic elastic modulus, and unloading elastic modulus of sandstone in dry conditions are considerably larger than those in moisture conditions, and the three parameters linearly decrease as the moisture content increases from 0% to 2.58%. The distribution law of sandstone fragments with different moisture contents has been investigated by sieving test fragments with different grain sizes of grading sieves. The results show that the percentage of large grain size fragments incrementally decreases, and the percentage of small grain size fragments incrementally increases with moisture contents from 0% to 2.58%. When the moisture content ranges from 2.01%∼2.58%, the fractal dimension linearly increases, which indicates that the higher the moisture content is, the larger the dimension of the broken sandstone is. The calculation results for energy indicate that the sandstone energy attains the peak value with 0% moisture content. When the moisture content ranges from 2.01%∼2.58%, the reflected energy increases, and the transmitted energy and dissipated energy linearly decrease. In addition, the surface energy of the sandstone with different moisture contents has been investigated by converting fragments into spheres with the corresponding size. The results indicate that the smallest surface area of sandstone is obtained in dry conditions, but its surface energy in dry conditions is larger than that in moisture conditions. When the moisture ranges from 0% to 2.58%, due to 3% illite and 2% chlorite clay minerals reacting with different proportions of moisture, the surface areas of sandstone fragments linearly increase and the surface energy of sandstone linearly decreases.

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