Impact of Alkali Concentration and Metakaolin Content on Accelerated Ageing of Egyptian Slag
Hamdy Abd El-Aziz Abdel Gawwad,
Hesham Mohamed Khater,
Saleh Abd El-Aleem Mohamed
Issue:
Volume 3, Issue 3, May 2015
Pages:
30-38
Received:
28 May 2015
Accepted:
6 June 2015
Published:
19 June 2015
Abstract: The present work aims to study the coupled effect of alkali concentration and metakaolin (MK) on the resistivity of ground granulated blast-furnace slag (GGBFS) to strength regression during ageing. GGBFS was activated by 6 and 10 wt., % containing mixture of sodium hydroxide (SH) and liquid sodium silicate (LSS) at a ratio of 1:1, respectively (namely GGBFS6 and GGBFS10). On the other hand, GGBFS10 was replaced by 10, 20, 30, 40 and 50 wt., % of MK, respectively. All hardened specimens were cured in 100% relative humidity (RH) at 37 ± 2°C for 28 days (zero time) then, aged at 95°C for 56 days. Experimental results showed that, the pH value of alkali activated samples (AAS) decreased as the amount of MK increased. Also, the pH of AAS derived from GGBFS10 was higher than that of GGBFS6. The strength regression resistivity (SRR) during accelerated ageing enhanced with the decrease of alkali concentration. The compressive strength for different investigated mixes was evaluated. Also, some selected hydration products were analyzed using infrared spectroscopy (FTIR), thermo-gravimetric analysis (TG/DTG) and X- ray diffraction (XRD) techniques to determine the mineralogical phase transition. The results of mechanical properties are in a good agreement with those of FTIR, TG/DTG and XRD techniques and confirm that the SRR during ageing increases with MK content.
Abstract: The present work aims to study the coupled effect of alkali concentration and metakaolin (MK) on the resistivity of ground granulated blast-furnace slag (GGBFS) to strength regression during ageing. GGBFS was activated by 6 and 10 wt., % containing mixture of sodium hydroxide (SH) and liquid sodium silicate (LSS) at a ratio of 1:1, respectively (na...
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Kinetic Parameters Survey for Manufacture of Pralidoxime
Daniel Antonio Shimizu Kitagawa,
Sabrina Teixeira Martinez,
Erick Braga Ferrao Galante,
Tanos Celmar Costa Franca
Issue:
Volume 3, Issue 3, May 2015
Pages:
39-51
Received:
18 June 2015
Accepted:
29 June 2015
Published:
14 July 2015
Abstract: Chemical agents represent a serious threat to the modern world. Among them, they stand out nerve agents because of its high lethality and dangerousness. They are typically organophosphate compounds, which act by inhibiting acetylcholinesterase, a key enzyme in the transmission of nerve impulses process. There are several forms of treatment for organophosphate poisoning, and pralidoxime (2-PAM) is the drug most used as reactivator of acetylcholinesterase. In this work, we developed the first three steps for the synthesis of 2-PAM, with the objective of obtaining data to calculate the kinetic parameters of these steps. These parameters may be used for the manufacture of 2-PAM in semi-pilot scale. Through the studies conducted it has been found that the preparation of the oxime has very rapid kinetics.
Abstract: Chemical agents represent a serious threat to the modern world. Among them, they stand out nerve agents because of its high lethality and dangerousness. They are typically organophosphate compounds, which act by inhibiting acetylcholinesterase, a key enzyme in the transmission of nerve impulses process. There are several forms of treatment for orga...
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