Application of Endurance Time Analysis in Seismic Evaluation of an Unreinforced Masonry Monument

In this article, seismic behavior of the main dome of a well-known middle-eastern historical- monument, “Imam Reza Shrine” (Mashhad, Iran) which is located in a high seismic area in Iran is evaluated. This study focuses on the response history analysis using intensifying dynamic excitations in the framework of Endurance Time Method. Endurance Time Analysis gives acceptable results for a wide range of earthquake intensities and considerably reduces the computational demand in comparison to the conventional Time History Analysis and Incremental Dynamic Analysis. The aim of this study is to investigate the applicability and efficiency of Endurance Time Analysis for masonry monuments and to suggest modifications and interpretations to improve compatibility of the results with Time History Analysis. In addition, to facilitate evaluation of the structural behavior, a dimensionless index, Cumulative Plastic Strain Index, is proposed as a criterion to compare structural performance in terms of the severity and the extent of damage as a function of earthquake intensity.     

Estimating the Seismic Performance of CFRP-Retrofitted RC Beam-Column Connections Using Fiber-Section Analysis

Over the past two decades, many experimental techniques have been developed to improve the efficiency of the externally-bonded fiber-reinforced polymers (FRPs) in order to improve the structural performance of reinforced concrete (RC) beam-column connections. Numerical analysis is also being used as a cost-effective tool to predict the experimental results and to further investigate the parameters that are beyond the scope and capacity of experimental tests. In this study, at first, a fiber-section modeling approach is developed for estimating the seismic behavior of RC beam-column connections before and after application of FRP retrofits. The accuracy of the analysis results were validated against a series of the available experimental data under both monotonic and cyclic loadings. It was pointed out that the proposed model can predict the strength and displacement of un-retrofitted and FRP-retrofitted RC beam-column connections up to the failure points. The verified model was then used to perform a parametric study pertaining to the effect of longitudinal reinforcement ratio on the efficiency of the adopted FRP retrofitting technique to improve the structural behavior of RC beam-column connections.     

A late Holocene pollen record from Lake Almalou in NW Iran: evidence for changing land-use in relation to some historical events during the last 3700 years

A pollen diagram was prepared from Lake Almalou, a volcanic crater wetland located on the eastern flanks of the Sahand Volcanic Complex in NW Iran. The core provides a 3700-year record of human activity and environmental change in an upland region. We attempt to relate vegetation changes to both climatic change and historical events. Variations of anthropogenic pollen indicators suggest several phases of intensified human activities. Two strongly expressed agricultural phases are dated at about 2450–2220 cal BP (Achaemenid Empire) and 230–30 cal BP (collapse of Safavid Dynasty to the modern period). Historical rather than climatic events appear to be the main controlling factors for upland land-use dynamics. Fruticulture has been practiced in the region at least since the Iron Age, reaching its maximum importance 1500–1250 cal BP during the reign of Sassanid Empire; it declined by the time of Islamic conquest of Iran (651 AD). The Little Ice Age is tangibly recorded by higher lake water levels most probably due to both lower summer temperatures and higher annual precipitations. Low values of cereal-type and cultivated tree pollen during this period may indicate a change in the lifestyle from the cultivation of fields and orchards to a more nomadic life dominated by summer pasture. The modern period (1850 AD onwards) is characterized by expansion of agricultural activities to upland areas and intensified pastoralism.     

Al-Junayd on Unification and Its Stages: A Critical Examination

The purpose of this paper is to present a critical examination of al-Junayd's notion of unification (tawhid).¹ Al-Junayd is without doubt one of the most prominent Sufi leaders of the tenth century A.D. who left their mark on the Sufi traditions. He is remembered especially for his strong advocacy of strict adherence by Sufis to the Quar'an and the Sunnah of the Prophet. His Sufi views called for thorough introspection, purification of one's heart and soul, and conformity to the highest morals. To acquire a more accurate and comprehensive understanding of tawhid, however, some other related Junaydian notions need to be presented where appropriate. The following issues will be discussed in this order: human beings' relationship to God, fana'² (perishing), unification and its stages, sahw³ (sobriety), and, finally, whether the state of unification is reached by an act of free will and whether this state is purely subjective, i.e., not subject to public demonstration.     

The Village in Contemporary Persian Poetry

This paper explores the ever-shifting symbiosis between the village motif, social justice and populist politics in Iran over the past three decades. The village has remained a recurring motif in Persian literature, employed by a variety of writers and state institutions for a range of means. As a symbol, it has been a conduit into which any ideology can be poured; the village allegory can be manipulated to both condemn and support the official policies of the state. A comparison of Iran’s pre- and post-revolutionary literature sheds light on the ways the state literati perpetuated an idealized picture of the village as an authentic, sacred space, increasingly associated with religious nationalism during the 1980s. The paper examines the key socio-political influences on the evolution of the pastoral motif, the work of state-sponsored official poets, and the impact of the village on the cultural doctrine of the Islamic Republic.     

Identification of surface dyeing agents of two bookbinding leathers from 19th-century Qajar,Iran, using LC–MS, μXRF and FTIR spectroscopy

Identifying tanning and dyeing agents of historical leathers is one of the less studied subjects. Therefore, this study aims to distinguish the surface dyeing agent of historical leathers along with the tanning agents. It helps to better understand the leather-making process of past centuries. For this purpose, two Iranian historical bookbinding leathers belonging to the Qajar era were investigated. The tannins were examined by ferric spot test and ATR-FTIR spectroscopy after being extracted from the leather corium layer. ATR-FTIR and μXRF spectroscopy were also used to study the characteristics of the leathers' surface, in both grain and corium layers. LC–MS was also used to analyze the extracts taken from the surface of the leather samples. The results showed the corium layer of leathers has a significant number of hydrolysable tannins, especially gallotannins, as tanning agents. The characteristics of their FTIR spectra are significantly similar to those of sumac. LC–MS results showed the presence of ellagic acid, as an indicator analyte, on the surface of the leathers. It indicates that tannin-rich plants, such as oak, have been used for dyeing these leathers. Investigation of the structural properties of the grain and corium layers also revealed the accumulation of copper and iron on the surface of the leathers. Accordingly, copper and iron, which reacted with tannins to give a black color, were the main dyeing factor used in both historical leather samples.