Sharif Digital Repository

The aim of this study was to investigate the possible reduction of air and noise pollution due to the substituent of motorcycles and personal vehicles with bicycles by the theoretical phase and to compare the exposure of a cyclist to noise pollution in using different modes of transportation in the field phase. In the theoretical phase, different scenarios were designed based on a 25% and 50% reduction in the volume of motorcycles and personal vehicles separately, as well as a simultaneous reduction of 50% for motorcycles and personal vehicles. The effect of running these scenarios on reducing air pollution was investigated using emission inventory model and on noise pollution by CadnaA... 

The passengers inside vehicles could be exposed to high levels of air pollutants particularly while driving on highly polluted and congested traffic roadways. In order to study such exposure levels and its relation to the cabin ventilation condition, a monitoring campaign was conducted to measure the levels inside the three most common types of vehicles in Tehran, Iran (a highly air polluted megacity). In this regard, carbon monoxide (CO) and particulate matter (PM) were measured for various ventilation settings, window positions, and vehicle speeds while driving on the Resalat Highway and through the Resalat Tunnel. Results showed on average in-cabin exposure to particle number and PM10 for... 

Auto-Exposure detection is a key feature in digital cameras and smart-phones. The image information can be used to detect scene over and under exposure passively. This paper introduces an effective optimal exposure detection function based on joint probability density function of the pixels in the scene  

Background and purpose: To protect against any potential adverse effects to human health from localised exposure to radio frequency (100 kHz–3 GHz) electromagnetic fields (RF EMF), international health organisations have defined basic restrictions on specific absorption rate (SAR) in tissues. These exposure restrictions incorporate safety factors which are generally conservative so that exposures that exceed the basic restrictions are not necessarily harmful. The magnitude of safety margin for various exposure scenarios is unknown. This shortcoming becomes more critical for medical applications where the safety guidelines are required to be relaxed. The purpose of this study was to quantify... 

Proxy signatures allow an entity to delegate its signing capability to a proxy which can sign messages on behalf of the delegator. We examine identity-based versions of proxy signatures which employ identity strings in place of randomly generated public keys. First, we give a new generic construction of identity-based proxy signatures from identity-based standard signatures and show that our generic construction is secure if the underlying identity-based standard signature is secure. In addition, we present the first identity-based proxy signature from Rivest, Shamir and Adleman (RSA), secure under the one-wayness of RSA in the random oracle model. We should highlight that the proxy key... 

Identity-based proxy ring signature concept was introduced by Cheng et al. in 2004. This primitive is useful where the privacy of proxy signers is required. In this paper, the first short provably secure identity-based proxy ring signature scheme from RSA assumption has been proposed. In addition, the security of the proposed scheme tightly reduces to the RSA assumption, and therefore, the proposed scheme has a proper advantage in security reduction compared to the ones from RSA. The proposed scheme not only outperforms the existing schemes in terms of efficiency and practicality, but also does not suffer from the proxy key exposure attack due to the use of the sequential aggregation... 

Electric arc welding is a routine operation in the construction of metallic structures, but the fumes generated during the welding process can threaten the health of welders. Fumes are undesirable products of the majority of welding operations and may have various detrimental effects on health. The purpose of this study was to investigate the effect of operational parameters of the shielded metal arc welding SMAW process on the emission of fumes. A dust monitor was used to measure the number and mass concentration of fumes generated by SMAW. Measurements were made at the distances of 23 cm hood inlet and 41 cm welder’s breathing zone from the weld point, with different values assigned to... 

Non-point source pollution of phosphorus (P) is a primary cause of eutrophication of aquatic ecosystems, and poses a persistent management challenge due to the dynamic and poorly understood processes controlling the transport and transformation of P at the watershed scale. We examined phosphorus inputs, retention, and riverine losses in 62 diverse watersheds that included a wide range of land cover and use (minimally disturbed to human dominated) and human P inputs in Minnesota, USA. Fertilizer inputs from row crop cultivation were the dominant source of P to agricultural watersheds. A large majority of P inputs was retained in watershed soils or removed in agricultural products. However,... 

Air pollution in urban centers has become a key public concern around the world. Apart from its adverse health effects, air pollution could impact less visible outcomes like cognitive performance. Standardized tests are a fixture of all education settings that are susceptible to pollution shocks because they require high cognitive function. Given that test scores are widely used as signals by parents, employers, and education institutions, pollution shocks could render tests unfair and unreliable. In this paper, we combine pollution data with test scores from a large testing institution in Iran between 2012 and 2017 to quantify the impact of short-term exposure to air pollution on test... 

Nonpharmaceutical measures such as social distancing can play an important role in controlling the spread of an epidemic. In this paper, we use a mathematical model combining human mobility and disease spreading. For the mobility dynamics, we design an agent-based model consisting of pedestrian dynamics with a novel type of force to resemble social distancing in crowded sites. For the spreading dynamics, we consider the compartmental susceptible-exposed-infective (SEI) dynamics plus an indirect transmission with the footprints of the infectious pedestrians being the contagion factor. We show that the increase in the intensity of social distancing has a significant effect on the exposure... 

Background: Gestational Diabetes Mellitus (GDM) is a health problem that is increasing around the world. Introduction: Prevention of GDM, rather than treatment, could have several benefits in terms of both health and economic cost. Even a slight reduction in maternal glucose in non-diabetic women, particularly in women at high risk for GDM, may have significant benefits for pregnancy results and the future health of off-springs. Probiotics are a relatively new intervention, which are assessed by mothers’ metabolism, and can reduce blood sugar levels, prevent gestational diabetes and reduce the maternal and fetal complications resulting from it. The aim of this study was to review the studies... 

Land use regression (LUR) has not been applied thus far to ambient alkylbenzenes in highly polluted megacities. We advanced LUR models for benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene (BTEX), and total BTEX using measurement based estimates of annual means at 179 sites in Tehran megacity, Iran. Overall, 520 predictors were evaluated, such as The Weather Research and Forecasting Model meteorology predictions, emission inventory, and several new others. The final models with R2 values ranging from 0.64 for p-xylene to 0.70 for benzene were mainly driven by traffic-related variables but the proximity to sewage treatment plants was present in all models indicating a major local... 

Ramsar, in the north of Iran by the Caspian Sea, has been known for the highest natural radiation background on Earth due to the local geology and hydrogeology. The residents and visitors use the hot springs that distribute the natural radionuclides especially 226Ra and its decay products in the areas. Many studies have been undertaken to measure the absorbed dose rate in Ramsar's air, however, no survey has been done to assess public internal exposure from ingestion of natural radionuclides, such as, a broad survey for 226Ra was conducted in foodstuffs and drinking water. This study presents the results of public annual activity intake (Bq) and effective dose (μSv) from ingestion of 226Ra... 

The hydrogen-induced cracking (HIC) behavior of X70 pipeline steel was studied by means of Linear Polarization Resistance (LPR), hydrogen permeation tests, weight loss and Scanning Electron Microscopy (SEM). In this study, the dissolved HZS was created by chemical reactions in solution. The specimens were immersed into synthetic sea water saturated with HZS. The experimental results showed that the increase of exposure time and HZS concentration leads to an increase of the hydrogen content in X70 steel, which plays a key role in the initiation and propagation of HIC  

Interactions of chemically exfoliated graphene oxide (GO) nanosheets and Escherichia coli bacteria living in mixed-acid fermentation with an anaerobic condition were investigated for different exposure times. X-ray photoelectron spectroscopy showed that as the exposure time increased (from 0 to 48 h), the oxygen-containing functional groups of the GO decreased by ∼60%, indicating a relative chemical reduction of the sheets by interaction with the bacteria. Raman spectroscopy and current-voltage measurement confirmed the reduction of the GO exposed to the bacteria. The reduction was believed to be due to the metabolic activity of the surviving bacteria through their glycolysis process. It was... 

Introduction: It has shown that listening to Mozart music can potentiate spatial tasks in human; and reduce seizure attacks in epileptic patients. A few studies have reported the effects of prenatal plus postpartum exposure of mice to the Mozart music on brain-drived neurotrophic factor (BDNF) in the hippocampus. Here we investigated the effect of postpartum exposure to The Mozart music on BDNF concentration in the hippocampus of rat. Methods: Thirty male one day old newborn Wistar rats divided randomly in two equal experimental and control groups. Experimental group exposed to slow rhythm Mozart music (Mozart Sonata for two pianos KV 448, 6 hour per day; sound pressure levels, between 80... 

This study examines the air quality on line 1 and 2 of Tehran underground metro. The total suspended particulate (TSP), PM10, PM2.5, PM1, CO2, NO, NO2, SO2, relative humidity and air temperature were measured. An integrated air quality index was also calculated for each location. The results revealed that, PMlO, PM2.5, and SO2 concentrations are higher than their environmental standard levels. The in station CO2 levels are higher while its' in train levels are lower than environmental permissible level. The air quality index showed that the in-train air quality is more acceptable than the instation air quality  

TiO2 nanostructures with different morphologies (spherical, tube, leaf-like and flower-like particles) were synthesized via a facile hydrothermal process. Polycaprolactone (PCL)/10 vol.% TiO2 nanocomposites were prepared by solvent casting methods. In vitro bioactivity of the nanocomposite films was examined by immersion in the simulated body fluid (SBF) for up to 28 days. It was found that the morphology of titania nanostructures significantly influence the in vitro bioactivity of PCL/TiO 2 nanocomposites. This observation was attributed to the amount of anatase phase and the specific surface area of the TiO2 nanostructures, which provide high surface exposure to SBF