Hedvall Effect in Cement Chemistry
THE increased reactivity of a solid during and as a consequence of a crystalline transformation is commonly known as the Hedvall effect1–3. In a wider sense this effect may include increased reactivity near a transition point. The typical data quoted in support of the Hedvall effect refer to reactions in the binary systems containing silver salts with BaO, SrO and CaO yielding the reciprocal pairs4–7.
Formation and Hydration of Cement and Cement Compounds
This chapter explores an understanding of the complex physico-chemical phenomena associated with the formation and behavior of cementitious compounds that is is facilitated through the application of many different types of investigative methods. Of the thermal analysis techniques the differential thermal analysis (DTA), thermogravimetric analysis (TG), differential scanning calorimetry (DSC), and conduction calorimetric methods are more popularly used than others. They are more adaptable, easier to use, and yield important results in a short span of time. The aim of this chapter is to highlight the application of these techniques and some of the work reported, utilizing other related methods that are mentioned with typical examples.
A study of the local tissue reactions in man to cortisone and compound F. VI. Histopathological studies of the local effect of compound F in normal and pathologic skin of man.
After our previous negative studies (1) of the local effect of cortisone acetate in the skin of man, a year ago, a parallel study of 17-hydroxycorticosterone-21-acetate, Compound F, was outlined. Theoretically, Compound F should be the active steroid. It was so suggested by Rothman (2), that in all probability Compound F and not cortisone would be active locally in the skin of man.