Particle Size and the Mechanical Properties of Uganda Clay

Obwoya, S. K.; Baker, T.W.; Soboyejo, W. O.

doi:10.1080/10426910601063337

Cited by 5 publications

(3 citation statements)

References 12 publications

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“…The values of γ estimated from the bridging ligaments microstructure show an increasing trend, with samples fabricated from larger particle sizes generally having higher values than those obtained from smaller particle sizes. This is consistent with prior results by Obwoya et al [11] obtained from ball clay specimens fabricated from larger particle sizes. These exhibited higher values of thermal shock lives than those fabricated from smaller particle sizes.…”

Section: Discussionsupporting

confidence: 95%

Thermal Shock Resistance of a Kyanite-Based (Aluminosilicate) Ceramic

et al. 2010

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This paper presents the results of a combined experimental and theoretical study of microstructure and thermal shock resistance of an aluminosilicate ceramic. Shock-induced crack growth is studied in sintered structures produced from powders with different particle size ranges. The underlying crack/microstructure interactions and toughening mechanisms are elucidated via scanning electron microscopy (SEM). The resulting crack-tip shielding levels (due to viscoelastic crack bridging) are estimated using fracture mechanics concepts. The implications of the work are discussed for the design of high refractory ceramics against thermal shock.

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Section: Discussionsupporting

confidence: 95%

Thermal Shock Resistance of a Kyanite-Based (Aluminosilicate) Ceramic

et al. 2010

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“…The porous sections of the clay pot walls were mainly caused by uneven particle sizes used to make the clay pots that created a void in the walls, thereby allowing water transfer across the walls. In a study by Obwoya, Baker, and Soboyejo (2007), the authors substantiated the finding that particle size was directly proportional to the relative porosity. According to Dah-Traoré et al (2018), although the composition of the clay mixture was shown to affect the porosity, the temperature of the furnace during the sintering process was also observed as a contributing factor.…”

Section: Discussionmentioning

confidence: 88%

A novel method based on passive diffusion that reduces the moisture content of stingless bee (Heterotrigona itama) honey

Baroyi

Yusof

Ghazali

et al. 2019

J Food Process Engineering

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Stingless bee honey from Heterotrigona itama exhibits a high moisture content (>27.0%) and therefore, is highly susceptible to undesirable microbial fermentation unless it is reduced to less than 20%. This study aims to reduce the moisture content of honey using a novel method based on passive diffusion and monitor the subsequent changes in several properties of honey. To achieve this, approximately 50 mL of freshly harvested honey samples was placed in clay pots (4 cm diameter × 6 cm height), covered with lids, and stored at temperatures of either 25 ± 1°C, 60% relative humidity (RH), or 35 ± 1°C, 25% RH. The results showed that the moisture content and Aw of honey after storage were significantly reduced (p ≤ .05) from 25.8 to 19.5% and from 0.79 to 0.70, respectively. A similar level of reduction was achieved at 25°C, although this process took 21 days and resulted in some losses of honey solids due to cross‐wall diffusion. The reduction in moisture content also resulted in a decrease in pH and free acidity of honey and an increase in viscosity. The data obtained in this study indicate the feasibility of using clay pots as an alternative method to reduce the moisture content in honey and protect it against fermentative deterioration. Practical Applications Stingless bee honey is highly popular in Malaysia and many other countries as it is high in carbohydrates and possesses many health benefits such as antioxidants and antimicrobial properties. However, the honey is susceptible to fermentation as its moisture content often exceeds the level required for microbial stability. Traditionally, the moisture content of stingless bee honey is reduced by drying the honey in shallow trays at elevated temperatures. However, this leads to contamination if the drying is performed under unhygienic conditions. Therefore, this study proposed the application of a passive diffusion method that serves as an effective alternative for moisture reduction in honey. It is anticipated that this method will not only reduce the moisture content but also retain most of its properties when the filtration process is performed under appropriate conditions.

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“…Porous clay ceramics form an important class of refractory materials that are used widely as thermal insulators in high-temperature applications such as in kilns, furnaces, and domestic charcoal stoves (jikos). In such applications, these materials are often exposed to cyclic thermal stresses and, at times, even severe thermal shocks that can result in significant strength degradation [15,16]. There is, therefore, a need to relate the thermal shock behavior to the room-temperature strength degradation that is often observed in clays after thermal shock.…”

Section: Introductionmentioning

confidence: 99%

An Investigation of Thermal Shock in Porous Clay Ceramics

Nyongesa

Rahbar

Obwoya

et al. 2011

ISRN Mechanical Engineering

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The thermal shock resistance of porous ceramic materials is often characterized by the Hasselman parameters. However, in other scenarios, the room-temperature residual strengths after thermal shock are also used to quantify the damage due to thermal shock. This paper attempts to link the measured residual strengths to the dominant crack features that are introduced due to thermal shock in porous clay ceramics produced by the sintering of clay powders with well-controlled size ranges. Residual strength estimates from bend tests are compared with fracture mechanics predictions. The implications of the residual strength results are then discussed for the characterization of damage due to thermal shock.

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Particle Size and the Mechanical Properties of Uganda Clay

Cited by 5 publications

References 12 publications

Thermal Shock Resistance of a Kyanite-Based (Aluminosilicate) Ceramic

Thermal Shock Resistance of a Kyanite-Based (Aluminosilicate) Ceramic

A novel method based on passive diffusion that reduces the moisture content of stingless bee (Heterotrigona itama) honey

An Investigation of Thermal Shock in Porous Clay Ceramics

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