Sharif Digital Repository

The gelatin/gum arabic microcapsules encapsulating peppermint oil were prepared by complex coacervationusing tannic acid as hardening agent. The effects of various parameters, including concentration of wall material, core material, tannic acid and Tween 80 were investigated on particle size and encapsulation efficiency. For statistical evaluation of the parameters, Taguchi method was concerned. The size of prepared spherical microcapsules was 19-66 micrometers. The results showed that, particle size increased with increasing the core and the wall concentration and decreased with increasing tannic acid and Tween 80 concentraIfd efficiency increased by increasing the core and wall... 

Devising effective methods to reduce drag forces is of great interest as these methods could prevent the wastage of fuel and decrease carbon emission and the global warming rate. Since the invention of Liquid-Infused Surfaces (LISs) in 2011, numerous investigations have been conducted to study their capability in various applications. Due to recirculation or drawing of the penetrated liquid within the surface structure, these surfaces acquire a slippiness property. The conducted investigations showed that these slippery surfaces have great potential for reducing drag forces, whether in a laminar or turbulent flow. In the present work, we first briefly elucidate common drag reduction methods,... 

Drag force, corrosion, and biofouling have always been issues that disrupt the reliable operation of systems dealing with fluid flow. Inspired by nature, liquid- or solid-infused surfaces are brand-new surfaces that can address these problems. The present study examines nine comprehensive yet affordable samples with different surface structures, from the nanoscale to the microscale on the aluminum substrate. These surface structures, modified with stearic acid or octadecyltrichlorosilane, are infiltrated with various lubricants. The wetting test shows the magnificent slippery properties of fabricated surfaces with a contact angle hysteresis lower than 10°. The conducted polarization test... 

Liquefaction is a phenomenon through which saturated sandy soil loses its shear strength and turns into a liquefied state. One of the most detrimental consequences of liquefaction is the reconsolidation volumetric settlements after the earthquakes, which is due to the dissipation of excess pore pressure caused by earthquakes. Severe floods can follow these settlements in free fields such as grounds close to the sea or rivers. Several researchers studied this phenomenon using data obtained from experiments in the lab or observations in the fields. Previous works were mainly based on a limited number of experimental observations and considered loadings and boundary conditions that were... 

Superhydrophobicity is a potential solution for corrosion inhibition and to mitigate increased fuel consumption. The facile, low-cost, and stable coating is developed in the present study. The contact angle of the coating is 160.1˚. In the pull-off test, the required force to detach the coating from the aluminum surface is about 7.55 MPa. The durability of the fabricated coating is tested under different environmental situations. The coating shows a drag reduction of roughly 40% compared to bare aluminum in the laminar flow regime due to the hierarchical micro-nano structure of the coated surface entrapping air pockets which alter the water boundary layer. © 2022 Elsevier Ltd  

The power-to-liquid concept is a promising strategy to convert the power plants' flue gas to value-added liquid fuels using renewable energy. This technology could potentially reduce global greenhouse gases emissions and mitigate the environmental problems associated with the fossil fuels industry. In this regard, the main objective of the present study is to propose a novel power-to-liquid plant for the synthesis of formic acid and ammonia from power plants' flue gas, emphasizing the role of electrochemical technologies and renewable energy. The system's basis is developed by the integration of CO2 electroreduction cell, alkaline water electrolysis cell, and photovoltaic panel technologies.... 

The potential utilization of encapsulation techniques in food, pharmaceutical and agricultural products preparation, presents a new alternative for complementary technologies such as targeting delivery vehicles and carriers for active food ingredients. Encapsulation could be accomplished by different techniques like: simple or complex coacervation, emulsification technique, phase separation, spray drying, spray chilling or spray cooling, extrusion coating, freeze drying, fluidized-bed coating, liposomal entrapment, centrifugal suspension separation, co-crystallization and molecular inclusion complexation. Encapsulation is a method by which one bioactive material or mixture of materials is... 

Nowadays, one of the biggest concerns in the world is increasing the CO2 emissions and global warming due to the over-consumption of fossil fuels. In addition, under the intense market competition, the demand for more efficient systems with higher performance and lower energy consumption has escalated. Since the drag force contributes to a considerable percentage of the energy loss and reducing the performance, a large number of studies have been conducted to improve the surface characteristics and, subsequently, declining the drag force. Making the surface superhydrophobic is one of the most effective ways for this purpose. In this work, two different superhydrophobic surfaces using SiO2... 

We numerically investigate the pressure drop reduction (PDR) performance of microchannels equipped with liquid-infused surfaces, along with determining the shape of the interface between the working fluid and lubricant within the microgrooves. The effects of different parameters, such as the Reynolds number of working fluid, density and viscosity ratios between the lubricant and working fluid, the ratio of the thickness of the lubricant layer over the ridges to the depth of the groove, and the Ohnesorge number as a representative of the interfacial tension, on the PDR and interfacial meniscus within the microgrooves are comprehensively studied. The results reveal that the density ratio and... 

Improving the shedding rate of condensed droplets has many applications in industries and daily problems, including increasing heat transfer and self-cleaning properties. One way to achieve this goal is by enhancement of the wetting properties of surfaces. In this research, the hierarchical superhydrophobic coating over aluminum has been applied using a relatively cost-effective method, spraying, which is also applicable to any metal surface used as a condenser. According to the results obtained from the experimental tests, the fabricated surface is highly superhydrophobic, with a contact angle of 158° and contact angle hysteresis of less than 5°. The results show that the presented surface...