scholarly journals Novel Porous Refractory Synthesized from Diatomaceous Earth and Rice Husk Ash

Author(s):  
Nguyen Hoc Thang
2016 ◽  
Vol 118 ◽  
pp. 133-139 ◽  
Author(s):  
Johanna M. Mejía ◽  
Ruby Mejía de Gutiérrez ◽  
Carlos Montes

2018 ◽  
Vol 5 (11) ◽  
pp. 709-724
Author(s):  
M. O. Ashamo ◽  
A. I. Babalola ◽  
O. C. Ogungbite

This study was carried out to investigate the comparative toxicity of seeds of Piper guineense Schum & Thonn, Capsicum annum L., diatomaceous earth, pirimiphos-methyl dust, rice husk (powder and ash) against Callosobruchus maculatus (F.) in stored cowpea seeds. Toxicity test was carried out by exposing five pairs each of freshly emerged beetles to the substrate materials at the rates of 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5 g/20 g of grains. The experiment conducted at ambient temperature of 28 oC + 2 oC and 75% + 5% relative humidity was replicated three times and arranged in a completely randomized design. Adult mortality was observed for four days. The following phytochemicals were observed in the materials: alkaloids, saponins, tannin, flavonoid and glycosides. Results of the toxicity assay revealed that rice husk ash was the most toxic to adult C. maculatus with 100% mortality (p < 0.05) within 72 h of exposure at a concentration of 0.1 g/20 g grains. Pirimiphos methyl gave a significantly high mortality of 76.67% at a concentration of 0.2 g/20 g of grains in cowpea after 72 h of application. The least efficacy was observed with rice husk powder evoking 3.33% at a dosage of 0.3 g/20 g in cowpea. The treated grains significantly reduced the oviposition and adult emergence of C. maculatus and were significantly different from the control in all the different dosages. Oviposition and adult emergence were lowest in rice husk ash with 8 eggs and 24.62% adult emergence in C. maculatus, at 0.5 g/20 g dosage. The percentage adult emergence in the untreated grains was significantly different (higher) (p > 0.05) from the emergence in the treated cowpea grains across the dosages. At all levels of dosages, the powders and ash significantly reduced weight loss, damage and weevil perforation index caused by the beetle. Rice husk ash at 0.5 g dosage recorded the lowest weight loss, grain damage and weevil perforation index of 0.40%, 1.95% and 5.80%, respectively. The findings from this research showed that rice husk ash was most potent/toxic to C. maculatus and its use could be encouraged especially in small scale storage.


In many rice producing countries of the world, including in Vietnam, various research aimed at using rice husk ash (RHA) as a finely dispersed active mineral additive in cements, concrete and mortars are being conducted. The effect of the duration of the mechanoactivation of the RHA, produced under laboratory conditions in Vietnam, on its pozzolanic activity were investigated in this study. The composition of ash was investigated by laser granulometry and the values of indicators characterizing the dispersion of its particles before and after mechanical activation were established. The content of soluble amorphous silicon oxide in rice husk ash samples was determined by photocolorimetric analysis. The pizzolanic activity of the RHA, fly ash and the silica fume was also compared according to the method of absorption of the solution of the active mineral additive. It is established that the duration of the mechanical activation of rice husk ash by grinding in a vibratory mill is optimal for increasing its pozzolanic activity, since it simultaneously results in the production of the most dispersed ash particles with the highest specific surface area and maximum solubility of the amorphous silica contained in it. Longer grinding does not lead to further reduction in the size of ash particles, which can be explained by their aggregation, and also reduces the solubility of amorphous silica in an aqueous alkaline medium.


2014 ◽  
Vol 27 (2) ◽  
pp. 148-160
Author(s):  
Hassan K. Hassan ◽  
Najla J. Al-Amiri ◽  
Mohammed M. Yassen

2018 ◽  
Vol 60 (4) ◽  
pp. 3-7
Author(s):  
Thi To Yen Nguyen ◽  
Phung Anh Nguyen ◽  
Thi Thuy Van Nguyen ◽  
Tri Nguyen ◽  
Ky Phuong Ha Huynh ◽  
...  
Keyword(s):  
Red Mud ◽  

2015 ◽  
Vol 57 (4) ◽  
pp. 370-376 ◽  
Author(s):  
Ahmad Adlie Shamsuri ◽  
Ahmad Khuzairi Sudari ◽  
Edi Syams Zainudin ◽  
Mazlina Ghazali

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3440
Author(s):  
Mohd Na’im Abdullah ◽  
Mazli Mustapha ◽  
Nabihah Sallih ◽  
Azlan Ahmad ◽  
Faizal Mustapha ◽  
...  

The utilisation of rice husk ash (RHA) as an aluminosilicate source in fire-resistant coating could reduce environmental pollution and can turn agricultural waste into industrial wealth. The overall objective of this research is to develop a rice-husk-ash-based geopolymer binder (GB) fire-retardant additive (FR) for alkyd paint. Response surface methodology (RSM) was used to design the experiments work, on the ratio of RHA-based GB to alkyd paint. The microstructure behaviour and material characterisation of the coating samples were studied through SEM analysis. The optimal RHA-based GB FR additive was formulated at 50% wt. FR and 82.628% wt. paint. This formulation showed the result of 270 s to reach 200 °C and 276 °C temperature at equilibrium for thermal properties. Furthermore, it was observed that the increased contents of RHA showed an increment in terms of the total and open porosities and rough surfaces, in which the number of pores on the coating surface plays an important role in the formation of the intumescent char layer. By developing the optimum RHA-based GB to paint formulation, the coating may potentially improve building fire safety through passive fire protection.


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