Much importance was given to DRY DEPOSITION over the past few decades as it deteriorated the environmental conditions and resulted in subsequent health effects. This paper starts with an overall scenario of DRY DEPOSITION research; it focuses on: various particulate DRY DEPOSITION flux measurement methods, comparison of various published numerical values on DRY DEPOSITION VELOCITY and factors controlling DRY DEPOSITION VELOCITY. This work provides a technical overview to research studies on the current state of DRY DEPOSITION and limitations of various measurement methods. Relationship between DRY DEPOSITION flux and particle concentration is discussed with the help of previous works. Various mathematical models used to predict DRY DEPOSITION VELOCITY are discussed. DRY DEPOSITION VELOCITY of particulates around the world is compared to gain perspective on factors influencing DRY DEPOSITION.

Introduction & Objective: Heavy metals are major pollutants that can spread in the atmosphere with particulate matter and dust and because of the toxic and carcinogenic effects, their measurement and control is very important. Therefore, this study was conducted to assess Co, Cr and Mn concentration in the atmospheric DRY DEPOSITION collected from Hamadan city in 2014.Materials & Methods: After collection of 12 dust samples from 3 sampling stations and their laboratory preparation, metals concentrations were determined using ICP– OES. All statistical analyses were performed using the SPSS statistical package.Results: The results showed that the minimum and maximum mean concentrations of Co were 0.19 and 0.29 mg/kg for high and low traffic intensity sampling stations, respectively. The min and max mean concentrations of Cr were 0.65and 1.02 mg/kg for high traffic intensity and suburb sampling stations, respectively and the min and max mean concentrations of Mn were 7.23and 8.82 mg/kg for high and low traffic intensity sampling stations, respectively. Also comparing the mean concentrations of assessed metals with WHO permissible limits showed a significant difference (P<0.05). The mean concentrations of metals were significantly lower than the maximum permissible limits.Conclusion: Although the mean concentrations of Co, Cr and Mn are lower than the standard levels, lack of continuous monitoring of heavy metals concentrations in the dust and particulate matters in the air can lead to the entrance of various types of toxic pollutants such as heavy metals into the air and result in adverse health effects.

Background and purpose: The atmospheric suspended particulate matter is a major route of human exposure to different kinds of environmental pollutants especially toxic heavy metals. The aim of this study was to assess the carcinogenic and non-carcinogenic risk of cadmium in DRY DEPOSITION of atmospheric dust in Qazvin, Iran. Materials and methods: Glass traps were used for sampling DRY atmospheric dust. To determine the concentration of cadmium (Cd), the samples were injected into ICP-OES after preparation. Then, the risk of carcinogenicity and non-carcinogenicity of Cd was calculated in children and adults. Results: The mean concentration of Cd was 0. 0164 mg/kg. Cumulative non-carcinogenic risk (HI) in all exposure pathways for children and adults were 2. 31E-4 and 1. 94 E-4, respectively. The cumulative carcinogenic risk (TCR) in children and adults were 4. 72 E-9 and 9. 21 E-9, respectively. Conclusion: The risk of carcinogenicity and non-carcinogenicity due to the presence of cadmium in atmospheric dust and exposure in children and adults was found to be lower than acceptable limits. However, due to increasing air pollution in the future, it may cause harmful effects to the health of citizens.

One of the serious problems in the oil and petrochemical industry is the DEPOSITION of crude oil in the preheaters of the distillation unit. DEPOSITION increases the thermal resistance and increases the pressure drop in preheaters, which leads to increase of energy consumption and decrease of overall system efficiency. The main source of deposit in preheaters is a substance called asphaltene, which does not have a definite molecular composition. Generally, DEPOSITION involves two stages; one is the transport of insoluble particles to the surface and the other is to stick particles to the surface. So far, a major problem in the simulations is the lack of attention to phenomena that can play an important role near the surface and failure in modeling of particle stacking correctly. In this study, focusing on the boundary layer flow, phenomena that affect the particle DEPOSITION process near the surface were investigated. In this regard, the path of motion of particles is followed by Euler-Lagrangian approach, and the bonding stage is modeled using the concept of DEPOSITION critical VELOCITY. Numerical solver is validated using available experimental data for aerosol and also with the scanning electron microscopy data. Obtained results show that the dominant force that affects the particle motion in the boundary layer is Brownian force.The DEPOSITION VELOCITY is calculated for different diameters and it is shown that with the decrease in the diameter of the particles, the DEPOSITION VELOCITY increases.

DRY powder inhalers (DPIs) have attained considerable attention due to their propellant-free formulations and the patient’s inherent coordination with actuation. Generally, DPI formulations consist of a micronized drug alone or mixed with carrier particles. This study was carried out to investigate the effects of carrier particle size and weight fraction on aerosolisation behaviour of cromolyn sodium (CS). Pharmatose® 450M and Pharmatose® 325M, two commercial α-lactose monohydrate with different particle sizes, were blended in two different fractions (30 and 50% w/w) with CS. A low resistance device (Spinhaler®) and a medium resistance device (Cyclohaler®), were used to evaluate the effect of inhaler design on the DEPOSITION profiles of CS.The in vitro DEPOSITION of the formulations was determined using a twin stage impinger (TSI). Fine particle dose, fine particle fraction and emitted dose of the drug were depended to both formulation and inhalation devices. Fine particle fractions of the drug aerosolised from the formulations ranged from 9.35 up to 36.45%. The highest fine particle fraction was produced by formulation containing 50% Pharmatose® 450M as carrier. Cyclohaler® showed higher efficiency in aerosolisation of CS compared to Spinhaler®.

Freezing-melting cycles are a serious natural weathering for rock engineering projects and constructed structures on the rocks in mountainous regions. So evaluation of the rock geo mechanical parameters reduction due to freezing-thawing cycles is very crucial in these areas. In this study, shear wave VELOCITY and DRY density of intact and weathered schist samples (under freezing-thawing cycles of 7, 15, 25, 40 and 75) of the Angouran mine wall were measured. For each weathering cycle, 5 samples have been tested and calculations were made based on their average values. Results showed that by increasing the number of weathering cycles, the shear wave VELOCITY and DRY density values of samples are exponentially decreased while the initial cycles of freezing-thawing have the less effect on rock properties. By analyzing the obtained results, an experimental equation was extracted and proposed to calculate shear wave VELOCITY and DRY density in schist against the different cycles of freezing-thawing. Also, the texture of samples in intact status and after 75 cycles of freezing-thawing was studied by an electronic microscope. The results of microscopic study indicate that the texture of intact samples is denser than those of the weathered status. Also, after applying 75 cycles of freezing-thawing, the spacing between discontinuities has been increased and new cracks created in the samples body.