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Research Subject: Poly(dimethylsiloxane) (PDMS) is a silicone polymer that nowadays despite unique characteristics and high application potential of its microparticles, their preparation via bulk emulsification methods is a main challenge due to the limitations in mixing process, high viscosity and low surface energy of PDMS that make impossible accurate  control of final obtained particles. In the present work, size-controlled PDMS microparticles were prepared from a high-viscosity material.
Research Approach: PDMS microparticles were obtained by using glass capillary co-flow microfluidic device. The designed microfluidic device is facile, inexpensive and reusable and facilitated preparation of the high-viscosity PDMS microdroplets. Stabilizing the oil-in-water emulsion was obtained by optimizing the bath components and curing process that resulted in monodisperse and spherical PDMS microparicles. Effect of the some important adjustable parameters such as microchannel diameter and flow rate on the flow regimes and microparticles polydispersity were investigated by means of optical microscopy and scanning electron microscopy.
Main Results: Results showed a dripping regime for producing monodisperse microparticles at low flow rates of the continuous phase and monodisperse microparticles from it. On the contrary, microparticles obtained from jetting regime are more polydisperse and smaller in comparison with dripping regime. By reducing the diameter of inner microchannel, microparticles with a diameter of 1.83 µm were obtained. Using the designed technology, uniform nanocomposite PDMS/ZnO microparticles 318 µm in diameter containing 15% ZnO were obtained from an oil phase viscosity of 7550 mPa.s. Therefore by an optimized and facile method, size-controllable uniform microparticles can be prepared that are proposed for various applications including drug delivery, bioengineering and electronic industry.

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Laser cutting is one of the modern methods for cutting. In this method heat affected zone width and microstructure changes as a result and also sheet deformation are very low in comparison to other thermal methods and a fine cut is the result. The control of heat-affected zone (HAZ) during laser cutting of titanium sheets due to low thermal conductivity and high tendency to chemical reaction is of great importance. In this paper, the effect of some of the most important laser cutting parameters, including the type of assistant inert gas, stand-off distance, cutting speed and power on HAZ width was assessed in CW CO2 laser cutting of Ti-CP sheets, using Taguchi L16 orthogonal array. Metallography of the cut samples, effects of cutting parameters and optimal conditions of cutting were investigated. Taking into consideration the test results, it is suggested to select the highest possible cutting speed for thin Ti-CP sheets and provide the required severance energy by controlling the laser power. The use of helium instead of argon also showed a significant impact on the reduction of HAZ width. Finally, microstructure and hardness changes are presented.

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The aim of this research was to study soil structural stability indices of clay loam soil treated with organic amendments, using High Energy Moisture Characteristic (HEMC). For this purpose, three sizes of soil aggregates (0.5-1, 1-2, and 2-4 mm) were treated with three rates (0, 1.5, and 3 %) of vermicompost and urban waste compost. After three months of incubation, water retention of the slow (2 mm hˉˡ) and fast (100 mm hˉ ˡ) wetted soil aggregates were measured at six pressure heads from 0 to 50 hPa, and HEMC stability indices such as Volume of Drainable Pores (VDP), Stability Index (SI), and Stability Ratio (SR) were determined. The results showed that only the stability of 0.5-1 mm aggregates was significantly (P< 0.01) affected by organic treatments. The stability indices were significantly influenced by the rates of amendments, and increased with increasing their rates. However, the type of organic amendments had no significant effect on stability of aggregates. The mean ​​of VDP, SI, and SR decreased by increasing diameter of the aggregates and decreasing the rate of the organic amendments, due to breakdown of macro-aggregates and decrease of macropore fraction. In general, to increase structure stability of clay loam soil in arid regions of Iran, application of at least 3% organic amendments is recommended.

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Today, in Iran, we are confronted with a somewhat new phenomenon called white marriage, which is also referred to as adherence, homosexuality, black or gray marriage. White marriage is called for a kind of cohabitation without religious or customary identity. This way of life is more prevalent in big cities, especially the capital, which does not mean we are not in cities. One of the groups most associated with this phenomenon is the student community. In this article, we examine the sociological explanation of white marriage formation among the student community of Tehran. Therefore, in this research, we have investigated this issue among 16 couples using an in-depth interpretive methodological approach (Grand Theory) with an in-depth interview technique. After completing interviews and reaching theoretical saturation and finally coding and analyzing data, the categories of "economic problems", "low expectations in these relationships against formal marriage", "emotional deficiency", hot disgrace (divorce and its consequences) as causal conditions, "anonymity", "migration", "individualism", "reduction in the number of marriages" as contextual variables, "discretionary choice", familiarity with homosexuality, "weakening of religious values "as confusing conditions," psychological and sexual support", "women's desire to have a relationship "," men's unwillingness to have a relationship", "diversity "as interactions, " white wedding limitations "," ontological insecurity "as consequences of this type of life were determined.