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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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Research subject: Solar energy is a renewable resource that is abundant and can solve many problems of energy shortage. In order to use solar energy to desalinate water and produce high quality steam, one of the cheap and commercially proposed structures is floating solar steam generation system. In this system, water is transferred to the surface of the system in a controlled manner and is converted to steam using the heat generated in the photothermal layer. There are generally four main challenges in solar steam generation systems. These challenges include managing and preventing heat loss, structural strength, managing and transferring water within the structure, absorbing light and converting light into heat.
Research approach: In this paper, floating multilayer solar steam generation systems were fabricated in which porous polyurethane foam was used as the substrate and thermal insulation layer. Moreover, felt was used as the water-transfer layer. Photothermal materials including graphite, gold, and mixtures of graphite and gold were used as the light-absorbing layers to produce high-quality steam. Also, in order to determine the water evaporation rate and the efficiency of the systems, the amount of changes in water mass and system temperature has been measured.
Main results: Among the different solar steam generation systems studied, the system made of graphite-gold mixture absorber is able to produce steam at a rate of 1.257 kg.m^-2.h^-1. This rate is equivalent to an efficiency of about 82%. To evaluate the performance of the systems in more real situation, they were tested using seawater. As resulted, the rate of evaporation of seawater by the graphite-gold mixture system is 1.201 Kg.m^-2.h^-1 and its efficiency is 78.4%.