Factors affecting the shrinkage of fly ash geopolymers

The shrinkage of fly ash geopolymers was studied in the present study.Fly ash was used as the source material for making the geopolymers.The effects of the concentration of Na0H,sodium silicate-to-NaOH ratio,liquid-to-ash ratio,curing temperature,and curing time on shrinkage were investigated.The geopolymers were cured at 25,40,and 600C,respectively.The results indicate that the shrinkage of geopolymers is strongly dependent on curing temperature and liquid-to-ash ratio.The increase in shrinkage is associated with the low strength development of geopolymers.It is also found that NaOH concentration and sodium silicate-to-NaOH ratio also affect the shrinkage of geopolymers but to a lesser extent.     

Development of a knowledge‐based system for nonpowered hand tools (Tool Expert): Part I—The scientific basis

The need for developing a clear and concise guide for designing, selecting, and using hand tools would minimize if not eliminate acute–chronic trauma exposure factors and help improve efficiency, well‐being, and morale. Despite several research efforts devoted to the exploration and understanding of the interrelation between human capabilities, task requirements, nature of tasks, and ergonomically designed hand tools, there appear to be several problems in utilizing existing knowledge in practical use. One of the most important barriers is the lack of interaction of several specialists from different backgrounds. In this article, TOOL‐EXPERT, a knowledge‐based system developed to assert the ergonomical nonpowered hand tool design, selection, and use, is explained, which will provide a guideline to several users from various backgrounds. The system is designed to run in any IBM‐compatible personal computer system. Knowledge from several domains was included. The type of knowledge used in the research was selected to be a declarative knowledge. Altogether it includes 423 goals, 35 questions, and 40 rules. © 2004 Wiley Periodicals, Inc. Hum Factors Man 14: 257–268, 2004.     

Factors affecting the shrinkage of fly ash geopolymers

The shrinkage of fly ash geopolymers was studied in the present study.Fly ash was used as the source material for making the geopolymers.The effects of the concentration of NaOH,sodium silicate-to-NaOH ratio,liquid-to-ash ratio,curing temperature,and curing time on shrinkage were investigated.The geopolymers were cured at 25,40,and 60℃,respectively.The results indicate that the shrinkage of geopolymers is strongly dependent on curing temperature and liquid-to-ash ratio.The increase in shrinkage is associate...