A survey of temperature and precipitation based aridity indices in Iran

In arid and semi-arid lands with warm climates, aridity and associated water scarcity is more severe because of greater populations and associated water use. The goal of this study was to explore the spatial and temporal variations of the de Martonne and Pinna aridity indices over Iran based on temperature and precipitation data from 41 stations for 40 years (1966e2005). The spatially interpolated maps of the aridity indices were prepared using the Ordinary Kriging technique in a GIS environment. The arid and semi-arid regions cover about 88% of Iran according to the de Martonne index, while about 96% of the country’s areas are classified as dry and semi-dry based on the Pinna index. A strong relationship was found between the values of the de Martonne and Pinna indices, confirming their similar spatial distribution. Around 63% of the two indices series had a decreasing tendency. The significant decreasing trends of the aridity indices were observed mainly in the western and northwestern regions of the country. The relative changes of the aridity indices at the stations with significant decreasing trends were in the range of 18% - 54%.publisher: Elsevier articletitle: A survey of temperature and precipitation based aridity indices in Iran journaltitle: Quaternary International articlelink: http://dx.doi.org/10.1016/j.quaint.2014.03.061 content_type: article copyright: Copyright © 2014 Elsevier Ltd and INQUA. All rights reserved.status: publishe

An Explicit/Implicit Lead to Producing Requests: Eliciting Learners’ Awareness or Soliciting Metapragmatic Knowledge

This study attempted to investigate the extent to which two types of pragmatic instruction -explicit versus implicit- affect learners’ knowledge in terms of their awareness and production of request strategies. Thirty students with the same level of proficiency were divided into two groups (explicit and implicit). They were exposed to listening excerpts taken from the book Tactics for Listening, with the focus on request making strategies. While the explicit group was equipped with direct awareness-raising tasks and written metapragmatic explanations on the use of appropriate requests, the implicit group was provided with a set of implicit awareness-raising tasks. Outcomes of the study demonstrate that pragmatic instruction of requesting improved learners’ awareness of both groups. Also an improvement of learners’ production of requests did take place in both groups after the interventional period. However, the explicit group outperformed the implicit one as far as production of request making was concerned.

A computational approach for estimating and minimizing construction-related and end-of-life carbon footprint of concrete structures

This thesis presents the results of a comprehensive study conducted to develop reliable methods for estimating and minimizing the carbon emissions incurred in construction and end-of-life phases of a concrete structure. Through developing such methods, this thesis addresses an existing gap in the scientific literature which has been traditionally focused on cradle to site embodied carbon as well as operating carbon of buildings; and thereby complements the existing methods to enable achieving a full life cycle carbon emission estimate for concrete structures. A simplified computational method to estimate construction carbon emissions based on quantity take-offs from Building Information Models is presented. The method is then improved by accounting for uncertainty and the idling time of equipment to develop a more precise construction emission estimation method. The improved estimation method targets concreting and lifting operations as the most carbon-intensive operations in construction of a concrete structure. The estimation method is coupled with optimization models to minimize associated carbon emissions by optimizing concrete placing and lifting operations. The collected data from an actual construction project in Sydney are used to verify the presented carbon emission estimation methods. In addition, a framework to minimize the end-of-life carbon emissions of a concrete structure through estimating and comparing the emissions associated with different possible recycling and landfilling strategies is presented. The thesis finally concludes by highlighting the importance of incorporating the proposed methods as a part of a wider life cycle carbon footprint assessment method, to evaluate various design decisions in practice, by presenting a case involving selection of structural system for a building. The effects of different structural systems, height of the structure and type of material on associated life cycle carbon emissions are studied to highlight the importance of achieving a realistic estimate of carbon emissions as an important input into decision-making process in early design phase of construction projects

Monitoring and Analysis of Drought Using Gravity Recovery and Climate Experiment (GRACE)

Drought monitoring needs comprehensive and integrated meteorological and hydrologic data. However, such data are generally not available in extensive catchments. The present study aimed to analyze drought in the central plateau catchment of Iran using the terrestrial water storage deficit index (TSDI). In this arid catchment, the meteorological and hydrologic observed data are scarce. First, the time series of terrestrial water storage changes (TWSC) obtained from the gravity recovery and climate experiment (GRACE) was calculated and validated by the water budget output. Then, the studied area was divided into semi-arid, arid, and hyper-arid zones and the common drought indices of SPI and RDIe within a timescale of 3, 6, and 12 months were calculated to compare the results obtained from the TSDI by using the meteorological data of 105 synoptic stations. Based on the results, the study area experienced a drought with extreme severity and expansion during 2007–2008. The drought spatial distribution map obtained from three indices indicated good conformity. Based on the maps, the severity, duration, and frequency of drought in the semi-arid zone were greater than that in other zones, while no significant drought occurred in the hyper-arid zone. Furthermore, the temporal distribution of drought in all three zones indicated that the TSDI could detect all short- and long-term droughts. The study results showed that the TSDI is a reliable, integrated, and comprehensive index. Using this index in arid areas with little field data led to some valuable results for planning and water resource management