Sharif Digital Repository

Due to their different sizes and operational characteristics, vehicles other than passenger cars have a different influence on traffic operations especially at intersections. The passenger car equivalent (PCE) is the parameter that shows how many passenger cars must be substituted for a specific heavy vehicle to represent its influence on traffic operation. PCE is commonly estimated using headway-based methods that consider the excess headway utilized by heavy vehicles. In this research, the PCE was estimated based on the delay parameter at three signalized intersections in Tehran, Iran. The data collected were traffic volume, travel time for each movement, signalization, and geometric... 

We revisit and shed light on the millennium-old hydrogeology textbook The Extraction of Hidden Waters by the Persian mathematician and engineer Karaji. Despite the nature of the understanding and conceptualization of the world by the people of that time, ground-breaking ideas and descriptions of hydrological and hydrogeological perceptions such as components of hydrological cycle, groundwater quality and even driving factors for groundwater flow were presented in the book. Although some of these ideas may have been presented elsewhere, to the best of our knowledge, this is the first time that a whole book was focused on different aspects of hydrology and hydrogeology. More importantly, we... 

Observing the growing energy demand of modern societies, many countries have rec-ognized energy security as a looming problem and renewable energies as a solution to this issue. Renewable hydrogen production is an excellent method for the storage and transfer of energy generated by intermittent renewable sources such as wind and solar so that they can be used at a place and time of our choosing. In this study, the suitability of 15 cities in Fars province, Iran, for renewable hydrogen production was investigated and compared by the use of multiple multi-criteria decision-making methods including ARAS, SAW, CODAS, and TOPSIS. The obtained rankings were aggregated by rank averaging, Borda... 

The origins and evolution of the Middle Eastern dust storms which frequently impact the residents of this arid region were studied. A methodology was adapted and developed to identify the desert regions of potential dust sources and determine their contributions to PM10 concentrations in the highly-populated receptor city of Tehran, Iran. Initially, the episodes of regional dust intrusion and the resulting amounts of increase in the particulate concentrations during these episodes were determined using a statistical analyzing methodology. The dust episodes were also inspected with the aerosol index information from the Ozone Monitoring Instrument (OMI). The Hybrid Single-Particle Lagrangian... 

In the present paper, spatially variation input effects on seismic responses of arch dams have been studied. Recorded ground accelerations at the dam foundation interface of Pacoima dam during January 13, 2001 were used for the purpose of this investigation. A numerical finite element model was developed for dynamic analysis of the dam reservoir system. The modified version of NSAD-DRI finite element program was used for the analysis and the ground acceleration time histories were interpolated at all dam foundation interface nodal points. Total and pseudo static displacements as well as developed stresses due to uniform and non uniform excitations are obtained. The results reveal that... 

Extensive tests were carried out on a section of a wind turbine blade. The effect of reduced frequency on the boundary layer transition point of the model oscillating in plunge has been investigated. The spatial-temporal progressions of the transition point and the state of the unsteady boundary layer were measured using multiple hot-film sensors. The measurements showed that reduced frequency highly affects variations of the transition point and results in a hysteresis loop in the dynamic transition locations. The dominated frequencies of the boundary layer are found to be a function of the reduced frequency and mean angle of attack  

The effect of an intermediate standing baffle on the flow structure in a rectangular open channel has been investigated by a three-dimensional acoustic Doppler velocimeter. Investigation of time-averaged velocity profiles at different streamwise positions reveals that the approach flow is fully developed upstream of the baffle. By analysing the space-averaged power spectra of streamwise velocity, a peak structure was observed in the upstream baffle region. Downstream of the baffle this peak structure has been alleviated by the baffle. The same analysis for the vertical component indicates the existence of a peak structure both up- and downstream of the baffle. Consequently, a baffle affects... 

Since 2000, many countries have achieved considerable success in improving child survival, but localized progress remains unclear. To inform efforts towards United Nations Sustainable Development Goal 3.2—to end preventable child deaths by 2030—we need consistently estimated data at the subnational level regarding child mortality rates and trends. Here we quantified, for the period 2000–2017, the subnational variation in mortality rates and number of deaths of neonates, infants and children under 5 years of age within 99 low- and middle-income countries using a geostatistical survival model. We estimated that 32% of children under 5 in these countries lived in districts that had attained... 

One of the most effective measures for building energy conservation is the implementation of energy codes. The building energy codes introduction in Iran started two decades after the first oil crisis in the early 1970s by establishing the building energy conservation regulation called Issue 19. Nowadays, due to some financial and executive barriers, the implementation of Issue 19 is faced with some difficulties. The most critical obstacle is the low price of energy carriers, which lead to high subsidies of energy and the reluctance of the building owners to implement the regulation. The main goal of this paper is the introduction of an innovative financial and executive mechanism for... 

In Iran, due to arid and semi-arid climate, groundwater resources play an essential role in food production, as well as domestic and industrial water supply. In recent years, increasing population, scarcity of surface water resources, and effects of worldwide and regional climate change have resulted in over-exploitation and unsustainability of these resources in the country. The present study aims to estimate groundwater sustainable yield, examine effects of spatial and temporal scale, and propose a plan for groundwater sustainable use in Nishapur Plain, in the north-east of Iran. In investigating the effects of spatial scale, the area of the plain is divided into several zones, with... 

Utilizing ground-based measurements to obtain water budget components, especially in large scale basins, is challenging due to the limitation in the spatiotemporal availability of in-situ data. In this paper, we propose a probabilistic framework for estimating water budgets in low runoff regions using remote sensing products. By studying water budgets in the Central Basin of Iran (CBI) over 8 years period (2009–2016), we investigate the locations and time scales at which the water budget calculated from satellite products provides most closure. To this end, we use precipitation from the Tropical Rainfall Measuring Mission (TRMM), evapotranspiration from the Water Productivity Open Access... 

Bathymetric mapping for an accurate estimation of stored water volume in drying lakes is a key information for an effective monitoring of their recession or restoration status. Extraction of bathymetry in shallow saline lakes using remote sensing techniques has always been challenging due to the complex influences imposed by the physical properties of substrate and the spatial variability of salinity. In this study, we developed a machine learning-based model to quantify the implicit, non-linear relationship between water depth and surface reflectance by leveraging extensive in-situ data and high-resolution satellite imagery. We trained and tested the learning model in the hyper-saline Lake... 

Assessment of groundwater quality monitoring networks requires methods to determine the potential efficiency and cost-effectiveness of the current monitoring programs. To this end, the concept of entropy has been considered as a promising method in previous studies since it quantitatively measures the information produced by a network. In this study, the measure of transinformation in the discrete entropy theory and the transinformation- distance (T-D) curves, which are used frequently by other researchers, are used to quantify the efficiency of a monitoring network. This paper introduces a new approach to decrease dispersion in results by performing cluster analysis that uses fuzzy... 

Objectives: The present experiment examined the role of age and fall history in upper body accelerations when walking on an even and on an uneven surface. Study design: An observational cross-sectional study. Main outcome measures: The magnitude (root mean square [RMS]), symmetry (harmonic ratio) and attenuation (attenuation coefficient) of upper body accelerations were quantified as primary outcomes; gait spatiotemporal parameters were measured as secondary outcomes. Methods: Twenty young adults (mean ± SD age: 29.00 ± 4.51 yrs), 20 older non-fallers (66.60 ± 5.43 yrs) and 20 older fallers (68.55 ± 4.86 yrs) walked on an even and on an uneven surface, while wearing four accelerometers... 

The spatiotemporal dynamic of salinity concentration (SC) in saline lakes is strongly dependent on the rate of water flow into the lake, water circulation, wind speed, evaporation rate, and the phenomenon of salt precipitation and dissolution. Although in-situ observations most reliably quantify water quality metrics, the spatiotemporal distribution of such data are typically limited and cannot be readily extrapolated for either long-term projections or extensive areas. Alternatively, remotely sensed imagery has facilitated less expensive and a stronger ability to estimate water quality over a wide range of spatiotemporal resolutions. This study introduces an adaptive learning model that... 

Oil spills are serious environmental issues that potentially can cause adverse effects on marine ecosystems. In some marine areas, like the Baltic Sea, there is a large number of wrecks from the first half of the 20th century, and recent monitoring and field work have revealed release of oil from some of these wrecks. The risk posed by a wreck is governed by its condition, hazardous substances contained in the wreck and the state of the surrounding environment. Therefore, there is a need for a common standard method for estimating the risks associated with different wrecks. In this work a state-of-the-art model is presented for spatial and stochastic risk assessment of oil spills from... 

The spatiotemporal variability of ambient volatile organic compounds (VOCs) in Tehran, Iran, is not well understood. Here we present the design, methods, and results of the Tehran Study of Exposure Prediction for Environmental Health Research (Tehran SEPEHR) on ambient concentrations of benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene (BTEX), and total BTEX. To date, this is the largest study of its kind in a low- and middle-income country and one of the largest globally. We measured BTEX concentrations at five reference sites and 174 distributed sites identified by a cluster analytic method. Samples were taken over 25 consecutive 2-weeks at five reference sites (to be used for...