The importance of market concentration for government decisions and policies to regulate the market is inevitable. In this study, market indexes were calculated to identify the market status of particleboard imports and to help industry practitioners to identify the particleboard market and identify production potential. In this study, the market structure was measured using concentration ratios, Herfindahl-Hirschman, Hall Tideman, Comprehensive Industrial Concentration, and Hannah-Kay. The market structure was measured for the period 2010-2019. According to the calculations, the average concentration ratio of the four major exporting countries to Iran for the ten-year period studied was 97. 81% of the total import of particle board to the country. They indicates a market with a multilateral monopoly. Other indicators include the Herfindahl-Hirschman index at 5, 561, the Hall Tideman index at 0. 54, the Comprehensive Industrial Concentration Index at 0. 79, and the Hall Tideman Index at α value of 0. 6 to 3. 12, α value was equal to 1. 5, to 2. 27 and α value was equal to 2. 5 to 2. 02. The results have shown that the market situation on the import of paticle board was the multilateral monopoly. The status of this monopoly has fluctuated and changed over the past ten years due to the political and economic decisions of governments and the change in domestic production of particleboard. In this market situation, exporting countries can argue over price and export rates. Turkey, United Arab Emirates, Thailand, Italy and Russia has been Iran's most important trading partner in the particleboard import market during the period under review, with the most imports being indexed to these countries, indicating a multilateral monopoly.

Background and objectives: Many of non-respiratory and respiratory disorders are associated with bioaerosols in indoor and outdoor air. The best conditions for bioaerosols life are high humidity and moderate temperatures, which exist usually in indoor spaces such as the prisons, where density of individual is high. Pathogen spreading centers cause the prisoners health at risk of disease outbreaks through airborne and breathing, sneezing, and coughing. Therefore, the aim of this research work was to measure concentration of particulate matters and also to identify and determine bacteria existing in the prisoners breathing air at high-density areas in one of the prisons and their relationship with each other.Materials & Method: we conducted this research during summer and winter of 2012. We used TSI apparatus for collecting particles (PM2.5 and PM10). Blood agar and EMB agar media were applied to measure bacteria in indoor air (bedchambers and clinical admission wards) of the prison. According to NIOSH 0800 method, High volume pump with 28.3 L/min flow and a Single-stage Anderson Impactor were used for sampling. The time of measuring for each plate was 2.5 min. Finally, the data achieved were analyzed using SPSS after counting and detecting bacterial colonies grown and determining its density (CFU/m3) for two consecutive seasons of summer and winter. The tests analyzed by SPSS were ANOVA, Post hoc, correlation, and Pearson correlation tests.Results: Amounts of particulate matter in bedchambers were exceeded than 24-hour EPA limits, while it was less than the limits in clinical admission wards. Gram-positive and gram-negative bacteria were found in three bedchambers (50% of the bedchambers); however, gram-positive bacteria were cultivated only in three bedchambers. The maximum bacterial contamination was measured at the main Lobby of the prison and bedchamber II and the minimum value was observed in admitted patient and TB patient wards. Results showed that there is no significant relationship between the particulate matters and the bacterial density during neither summer nor winter, but there is a strong and direct relationship between the prisoners population density, ventilation systems, and bacterial density n indoor air of the studied prison.Conclusion: Based on the results, the maximum contamination load and exceeded concentration was observed in public sections and bedchambers. This findings were attributed to the daily entry of new prisoners, high population density in prison, presence of ill prisoners, prisoners with hidden respiratory disease showing no symptoms yet, old building, climatic conditions of the region, low efficiency of ventilation systems, and influx of particulates. To filter and purify prison indoor air, it is crucial to take serious action plans such as reducing criminal population density, sanitary and engineering measures.

Cost and safety are two most important factors involved in the design of civil engineering systems and structures. Thus, the optimal design of structure dimensions is of big importance in order to reduce the cost of construction while meeting the safety requirement and the design constraints. Up to now several algorithms have been developed and used for optimization of different civil engineering problems. One of these algorithms is the Particle Swarm Optimization (PSO) which is a swarm intelligence based algorithm inspired by the social behavior of animals such as fish schooling and bird flocking to solve continuous problems. In this paper, an optimization model is developed for the optimal design of flood control systems which contain both detention dam and bottom outlet. The proposed model uses the powerful PSO algorithm as the search engine and The "Transport Module" of "SWMM" as the hydraulic analyzer of the system. The applicability of the model to solve real world problem is verified by the optimal design of of South Pars flood control system which contains both detention dam and bottom outlet. The results show that the proposed optimization model can considerably reduce the total costs of flood control systems.

In the present study, the Multi-Relaxation Time Lattice Boltzmann method (MRT-LBM) was employed to solve the airflow inside a scaled room model with dimensions of 0.914×0.457×0.305 m. This room model is considered a representative space with a 1:10 scale to an actual room. The selected room is equipped with a ventilation system. For optimizing the inlet and outlet locations of the airflow, 32 different positions in terms of length, width, and height for the inlet and 4 positions for the outlet were considered. The Taguchi method was utilized for optimizing the inlet and outlet locations, reducing the required number of experiments from 128 to 16. To assess the number of suspended particles, 86400 particles with a size of 1µm were injected into the room. Then, the particle behaviors were examined for a total duration of 60 seconds. The obtained results indicate that the location of the air conditioning system significantly influences the concentration of airborne particles responsible for disease transmission. Utilizing the Taguchi optimization method, optimal positions for the inlet and outlet air were determined to minimize the number of suspended particles in the room (the best position) and maximize it (the worst position).

In this article, Au nanoparticles in polyvinylpyrrolidone (PVP) solution were prepared by gamma radiation at different concentrations. The solutions were irradiated at doses of 50 kGy for making different sizes. The average sizes of particle in the prepared samples were measured using the nanophox machine. A dual-beam mode-mismatched thermal lens (TL) method was used to investigate the effect of thermal diffusivity of samples. The TL measurement was carried out using a green diode laser (wavelength 532 nm, 60 mW) and a He–Ne laser (wavelength 632.8 nm, 0.5 mW) for excitation source and probe beam, respectively. The results showed that the thermal diffusivity of samples enhances with the growth of particle size and density of solutions. This increment can be attributed to phonon scattering at interface of particles–liquid and contact between the nanoparticles and surrounded liquid.

In this paper, a two-dimensional computational model is implemented to study all the necessary phenomena in a simple one-stage plane depositor by considering the interactions between the electrostatic field, the flow field, the charge of the particles and their turbulent motions. In the first step of this paper, while presenting the connections between electrostatic fields, particle dynamics and fluid dynamics, the mathematical model of the corona field, air flow and particle motion is explained. In the following, the electrical conditions (electric field and space charge) and the induced flux pattern are analyzed by the interaction of ion wind and the main gas flux in the studied model. Also, while examining the path of movement and accumulation of particles, their sediment distribution in the channel is investigated and the partial efficiency of particles with different diameters is calculated. In the following, the effect of electrohydrodynamic flux on the efficiency of the equipment is investigated. Finally, considering the normal logarithmic distribution for particles at the input of the sediment channel, the effect of different concentrations of particles at the input on the overall efficiency of the equipment is analyzed. This model is simulated in COMSOL software.

In this research, a lithography ink formulation based on the Maleic and Alkyd resin has been prepared and its rheological parameters such as viscosity vs. shear rate, thixotropy cycle, storage and loss modules and dynamic viscosity were studied. It was observed that viscosity values augmented severely by increasing the pigments concentration and reducing the particle size distribution. Time dependence thixotropy values were significant in samples containing small particle size and high pigment concentration. Structural networking and association of carbon black particles as well as particle-particle and particle-binder interaction are reasons for this behavior. Storage and loss modules were increased with reduction of particle size and/or increasing of pigment concentration. Besides, the differences between dynamic parameters in low frequencies were obvious.