Authors: Dhimas Wicaksono, Xiao Meng Zhu, Mohammad Sukri Mustapa, Sulis Yulianto, Ahmad Yunus Nasution, Tri Widodo Besar Riyadi
Abstract: In this work, a ternary system prepared by Ni-Al-Ti mixed powder was synthesized using self-propagation high-temperature synthesis (SHS) process. The weight of the reactant was varied using 3%, 10%, 20% and 30% of the Ti content. The mixtures were compressed in a steel die to form compacted pellets, and subsequently ignited using an external heat source to initiate the combustion process. The synthesized products were characterized using SEM, EDS, and XRD, whereas the mechanical property of the product was measured using a Vickers microhardness test. The identification of the formed phase indicates that Ni-Al, Ti-Al and Ti-Ni systems were formed during the reaction. An increase of Ti content from 3% to 10% improves the density of the synthesized product. Further increase of Ti content to 20% results in the generation of cracks. The addition of Ti with 30% leads to the formation of a porous product. The heat released by the SHS process due to the formation of several intermetallic phases was responsible for the formation of defect products. The highest hardness of the product was achieved in the product prepared by 20% Ti content. However, the higher Ti content than 20% results in hardness reduction. This work shows that the content of 10% of Ti produced a dense and hard product.
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Authors: Alamin Idris, Zakaria Man, Adulhalim Shah Maulud, Sina Gilassi
Abstract: Cloud points at different polymer concentrations were obtained by the simple titration method and compared with the numerically calculated theoretical binodal curves for Polycarbonate/Dimethylacetamide/Water (PC/DMAc/Water) and Polycarbonate/N-Methyl-2-pyrrolidone/Water (PC/NMP/Water). The interaction parameters for solvent polymer and nonsolvent polymer were obtained from Hansen's solubility parameters. The cloud points determined were found to be in close agreement with the theoretical binodal curve calculated. Coagulation values for different solvents such as Dichloromethane (DCM), Dimethylacetamide (DMAc), N-Methyl-2-pyrrolidone (NMP) and Tetrahydrofuran (THF) were also determined and the results were plotted in a ternary diagram to realize the effect of interaction parameters on the coagulation values. The higher the mutual affinity of solvent to polymer (low χ23), the faster is the liquid-liquid demixing rate to occur. For DCM solvent, fastest demixing rate was exhibited and lowest for the THF.
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Authors: Chung Ho Huang, Chih Hsuan Ho
Abstract: This paper aims to investigate on producing lightweight aggregates made from the waste stone sludge. It was utilizing the mechanism of high temperature solid solution method as well as in coordination with the production method of reservoir sediments lightweight aggregates to conduct an investigation on the development of lightweight aggregate using stone sludge. The investigation shows that the analysis results for the stone sludge are not in the limits of the expandable region of the ternary diagram due to the high content of FeOx. That caused the expandable temperature range was narrow, the expandability of aggregate was poor and the aggregate particle density was relatively high. But, it still could be producing lightweight aggregates made from the waste stone sludge in this paper. The better solution may be to add the high-content organic materials to adjust chemical composition, such as water purification sludge, sewer sludge, reservoir sludge etc.
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Authors: Monique Tohoué Tognonvi, Séka Simplice Kouassi, Toyotaka Maeda, Julien Soro, Sylvie Rossignol, Jean Pierre Bonnet
Abstract: Consolidation of cements and geopolymers can be explained by the formation of alkali
silicate or alumino-silicate gels formed in situ during materials setting. To control such a system, a
study concerning the use of sodium silicate gel as binder was initiated to manufacture consolidated
materials with different size distribution of silica. The gels used as precursor of binder were
synthesised by acidifying with hydrochloric acid, a concentrated sodium silicate. Consolidated
materials were obtained by mixing the previous solution before gelation with granular materials
(fine silica powder and sands).
The existence domain of consolidated materials depends on the size distribution of sand.
Consolidation of material is strong when the amount of silica is high. This result suggests a
dissolution / precipitation reaction between gel and silica. Therefore, consolidation could be
explained by the dissolution of small particles of silica and their precipitation into the grain
boundary of sand. Mechanical properties are closed to those of cement materials.
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