Experimental Study on Postponing the Deboning of FRP Sheets in Masonry Walls

ABSTRACT

A large number of buildings all around the world are constructed of unreinforced masonry. These structures do not act well during earthquakes because of their vulnerable behavior. In last two decades, fiber-reinforced polymers (FRPs) has been used widely in seismic rehabilitation and strengthening unreinforced concrete and masonry structures. One important issue in using FRP composites for strengthening masonry walls is the inopportune debonding of composites from the wall surface; thus, in this article new methods are proposed to further delay the mentioned debonding issue. For this purpose, 13 masonry panels with 100x870x870 mm dimension are strengthened by using carbon and glass FRPs (CFRPs and GFRPs). A variety of strengthening methods such as surface preparation, boring, grooving, nailing, and plaster are used to mount FRP composites to the walls. For each specimen subjected to diagonal compression test, the loading level along with tensile and compressive diagonal displacements are evaluated. In order to assess the effect of FRP composites, four unreinforced masonry walls are tested as well. The results show 110% increase in ductility index of reinforced specimens compared to the unreinforced ones.     

Egyptian faience glazing by the cementation method part 1: an investigation of the glazing powder composition and glazing mechanism

In cementation glazing, for various reasons, there are significant differences between the composition of the glass phases present in the faience microstructure and the glazing powder composition. Furthermore, in this glazing method, the glazing powder should perform more functions, which are: producing a shiny and smooth glaze coating, producing a firm capsule surrounding objects entirely (to prevent adhesion between sintered glazing mixture and the melting glaze coating), and, finally, producing a porous and friable sintered glazing mixture for safe and easy removal of buried objects. It is obvious that these functions also have significant effects on the glazing powder composition and constitution. Therefore, analytical data on faience glass phases are very unlikely to reflect the strict composition and constitution of the original glazing powder properly. Accordingly, the composition and constitution of cementation glazing powder have remained obscure for a long time. These data are particularly crucial factors for cementation replication experiments and, consequently, for our awareness of the ancient faience production. In this paper, a series of cementation replication experiments have been conducted in an attempt to provide further clarification of these issues. In addition, as a comparative indicator for alkali and copper vaporisation, a small piece of rock quartz was placed separately above the glazing powder. After firing, the appearance of the faience objects and quartz pieces and the microstructures and chemical compositions of a select group of samples, obtained using Scanning Electron Microscopy – Energy Dispersive Spectroscopy (SEM-EDS), were investigated. The discussion has focused mainly on issues such as the raw materials and their contribution in the glazing process, the criteria for determining the faience glazing methods, the necessary quantity of alkalis for a successful cementation glazing, and, particularly, the glazing mechanism.     

On Liberty in Talebof's Thought

This article represents Talebof?'s thought on the modern idea of liberty defined in terms of selfishness, selflessness, and selfhood. First, a brief background is set forth in an attempt to show some of the influences on Talebof by others of the Iranian intelligentsia and European philosophers. Having set the stage, his philosophy is represented systematically, as against chronologically. This approach helps to reveal a shortcoming in Talebof?'s philosophy regarding the modern idea of liberty. The shortcoming is evident: Talebof defined liberty in terms of selfishness and selflessness, but then did not dig deep enough to methodically examine selfhood as a more fundamental basis for liberty. The article argues that this shortcoming was caused by a number of factors, including philosophical poverty coupled with natural tendency for reification, and anxiously pragmatic ethos caused by lawlessness under the Qajars and exposure to the hegemonic West. In short, this paper defines the modern idea of liberty, describes Talebof?'s understanding of it, and explains the obstacles that prevented Talebof from setting out a more comprehensive examination of the modern idea of liberty.