Sharif Digital Repository

Magnetically controlled double emulsions offer a promising tool for targeted drug delivery. Here, the effect of a non-uniform magnetic field induced by a permanent magnet on ferrofluid double emulsion generation and morphology is studied. In the numerical part, the double emulsion (and its ferrofluid core) migration was analyzed for different transverse distances of the magnet from the channel centerline (Ly) and different core and shell diameters. In the experimental part, water-based ferrofluid is encapsulated in a UV-curable polymer phase in water, forming a W/O/W double emulsion. As the magnet's downstream distance from the ferrofluid junction reduces, the core aspect ratio increases... 

In this paper, the experimental investigation of the performance of a concentrated hybrid photovoltaic thermal solar system is sought. Accordingly, there is a parabolic trough concentrator receiver that consists of three components: a triangular duct, photovoltaic cells covering the duct, and a three-turn PHP. The PHP cools down the photovoltaic cells efficiently and regenerates waste heat. The duct is filled with a heat transfer fluid surrounding the PHP's evaporator. The condensation section of the PHP is located outside the solar concentrator. Using a one-axis polar mechanism, the concentrator tracks the sun from east to west. The system experiment setup was fabricated and tested outdoors... 

Water scarcity is one of the most challenging problems that the world has ever faced. There are numerous methods to remedy the water crises. One is using atmospheric water harvesting (AWH) to provide water. So far, there is much research on the subject of AWH. However, there is still a lack of establishing an extensive comparison between different technologies and methods used to harvest atmospheric water. In this review, we provide details on the thermodynamic performance of the AWH system. The systems are categorized into both active and passive systems. Heat pumps, membranes, thermoelectric solar systems, and adsorption systems are some atmospheric harvesting technologies that will be... 

Nowadays, several engineering applications and academic investigations have demonstrated the significance of heat transfers in general and mixed convection heat transfer (MCHT) in particular in cavities containing obstacles. This study's main goal is to analyze the MCHT of a nanofluid in a triangular cavity with a pentagonal barrier using magneto hydrodynamics (MHD). The cavity's-oriented walls are continuous cold temperature, whereas the bottom wall of the triangle and all pentagonal obstacle walls are kept at a constant high temperature. For solving governing equations, we utilized the Galerkin's finite element approach. Four dimensionless factors, Richardson number (0.01 ≤ Ri ≤ 5),... 

Embracing an interaction between the phase change material (PCM) and the droplets of a heat transfer fluid, the direct contact (DC) method suggests a cutting-edge solution for expediting the phase change rates of PCMs in thermal energy storage (TES) units. In the direct contact TES configuration, when impacting the molten PCM pool, droplets evaporate, provoking the formation of a solidified PCM area (A). Then, they reduce the created solid temperature, leading to a minimum temperature value (T min). As a novelty, this research intends to maximize A and minimize T min since augmenting A expedites the discharge rate, and by lowering T min, the generated solid is preserved longer, resulting in... 

The mixed convective heat transfer in a two-dimensional enclosure containing ethylene glycol-water mixture-based MoS2 nanofluid in the presence of magnetic field and thermal radiation is evaluated, adopting Galerkin standard finite element method. The Boussinesq approximation is applied to simulate natural convection. The partial differential governing equations with the appropriate boundary conditions are numerically handled using FlexPDE software. In order to validate the implemented numerical method, results were compared against outcomes obtained from the previous studies. Afterward, the influences of key indicators such as Hartmann number (Ha), Radiation parameter (Rd), Volume fraction... 

The unique concept of generating electricity from a thermosyphon heat pipe (THP) utilizing an oscillating magnet in the adiabatic section was successfully examined experimentally. Generating electrical power while the THP operates is a revolutionary approach to improving its performance. In this regard, an energy harvesting module, including a magnet, was designed, built, and installed into the adiabatic section of the THP. The investigation was performed for four filling ratios ranging from 10 to 40%, while water served as the working fluid. In addition, the effect of variation of heat input on the performance of both THP and oscillating magnet thermosyphon heat pipe (OM-THP) was studied.... 

Liquid marbles are droplets encapsulated by a layer of hydrophobic nanoparticles and have been extensively employed in digital microfluidics and lab-on-a-chip systems in recent years. In this study, magnetic liquid marbles were used to manipulate nonmagnetic liquid marbles. To achieve this purpose, a ferrofluid liquid marble (FLM) was employed and attracted toward an electromagnet, resulting in an impulse to a water liquid marble (WLM) on its way to the electromagnet. It was observed that the manipulation of the WLM by the FLM was similar to the collision of billiard balls except that the liquid marbles exhibited an inelastic collision. Taking the FLM as the projectile ball and the WLM as... 

This paper presents the melting process of immiscible binary phase change materials (PCMs) in a rectangular enclosure which was subjected to isothermal heating from one vertical wall at 60 °C. Ice and oleic acid (OA) were selected as polar and nonpolar PCMs, respectively, resulting in immiscibility between the two materials. Initially, the melting process of each PCM was separately studied. Afterward, the melting process of the lighter density material (OA) placed on the denser material (ice) was investigated. In this case, there was no displacement between two materials. Then, the cases were studied in which ice was placed on top of OA with various volumetric ratios. The displacement... 

Digital images allow for the objective evaluation of facial appearance and abnormalities as well as treatment outcomes and stability. With the advancement of technology, manual clinical measurements can be replaced with fully automatic photographic assessments. However, obtaining millimetric measurements on photographs does not provide clinicians with their actual value due to different image magnification ratios. A deep learning tool was developed to estimate linear measurements on images with unknown magnification using the iris diameter. A framework was designed to segment the eyes’ iris and calculate the horizontal visible iris diameter (HVID) in pixels. A constant value of 12.2 mm was... 

In this survey, the integration of a vapor compression cycle with a phase change material (PCM) storage tank has been evaluated experimentally during the hottest days of five cities with different weather conditions: Tehran, Ramsar Hamedan, Bushehr, and Ahvaz. The temperature conditions for outdoor (condenser, compressor, etc.) and indoor (evaporator) air conditioning units are provided with the help of two separated test chambers and a controller system. The desired system has been examined based on two scenarios. In each scenario, the system is assessed for the conventional air conditioning (AC) system (with no PCM involved) and the AC plus PCM unit. Based on scenario 1 operating strategy,... 

In this work, experimental and numerical investigations were performed to evaluate the heat transfer efficiency of a single turn pulsating heat pipe by using distilled water as base fluid and distilled water with micro particles (micro-coppers). The pulsating heat pipe was manufactured with copper capillary tube by choosing the internal and external diameter 4 mm and 6 mm, respectively. The effect of filling ratio (40, 50 and 60%), heat input (20, 30, 40, 50 and 60 W) and concentrations of micro-coppers (0.0625 g ml−1 and 0.125 g ml−1) in distilled water as base fluid were studied. Experimental findings displayed that the thermal resistance of the system using micro-coppers declined with... 

Liquid marbles are being promoted as a replacement for conventional droplets in digital microfluidics. Liquid marbles can be remotely controlled by an external magnetic field if ferrofluid is utilized as their liquid cores. In this study, the vibration and jumping of a ferrofluid marble is experimentally and theoretically investigated. An external magnetic field is utilized to induce deformation in a liquid marble and an increase in its surface energy. As the magnetic field is switched off, the stored surface energy converts to gravitational potential and kinetic energies until it is dissipated. An equivalent linear mass-spring-damper system is used to study the vibration of the liquid... 

The current research attempts to illustrate results of a reliable 3-D numerical simulation to scrutinize the charging process of paraffin as the phase change material (PCM) in an innovative heat exchanger called double spirally coiled tube heat exchanger (DSCTHE) with two separated paths. The water as a heat-transfer fluid (HTF) streams through the double spiral tubes embedded throughout the latent thermal energy storage (LTES) system. The PCM melting characteristics under three different geometries are investigated. After validating the proposed numerical simulation model, the impacts of operational and geometrical factors including inlet temperature of HTF and radius of the inner spiral... 

Using super-resolution (SR) algorithms, an image with a low resolution can be converted into a high-quality image. Our objective was to compare deep learning-based SR models to a conventional approach for improving the resolution of dental panoramic radiographs. A total of 888 dental panoramic radiographs were obtained. Our study involved five state-of-the-art deep learning-based SR approaches, including SR convolutional neural networks (SRCNN), SR generative adversarial network (SRGAN), U-Net, Swin for image restoration (SwinIr), and local texture estimator (LTE). Their results were compared with one another and with conventional bicubic interpolation. The performance of each model was... 

Although momentous in numerous authentic applications, multiple droplet impacts on the liquid pool are overlooked in most studies. Hence, the impingement of simultaneous double ethanol droplets on the molten phase change material (PCM) pool, instigating the evaporation of droplets and the solidification of PCM, is comprehensively scrutinized for the first time. Experiments were carried out through high-speed imaging for various Weber numbers ranging from 179 to 464, pool temperatures from 70 to 95 °C, and several horizontal impact spacing. By altering impact parameters, five distinct regimes were observed in the case of double droplets. Based on observations, regime maps were also... 

In this research, a novel cooling system based on the combined use of a microchannel heat sink and pulsating heat pipes has been introduced. The pulsating heat pipe is considered a part of the microchannel heat sink structure, and it is the first time that these two systems have been studied simultaneously. Pulsating heat pipe has been modeled in a three-dimensional form in the wall of the microchannel heat sink, and the two-phase volume of fluid (VOF) model was used for numerical modeling. The effect of the physical and geometrical parameters of the pulsating heat pipe, such as the filling ratio and the number of loops, on the thermal performance of the microchannel heat sink has been... 

The preheating system is regarded as an integral part of a natural-gas pressure reduction station (NGPRS) when a turbo-expander is substituted with regulators. In this paper, two configurations are compared for optimal designing preheating system used in NGPRS with the turbo-expander system. The first case uses water for a hot fluid that is warmed in the gas-fired heater (GFH), and the second is a Waste Heat Recovery (WHR) configuration. Multi-objective optimization and multi-criteria decision-making (MCDM) methods are implemented to identify the optimal design of mentioned preheating systems and to acquire the ability for the designer to select the optimal solution readily. The total cost... 

Thermal performance maximization is a necessity in various systems that are dealing with any scale of heat flux. This requirement has been intensified due to introduction of more complex and highly crammed products, making heat dissipation a daunting task. Addressing this challenge, a curved porous star-shaped enclosure with a rounded cavity and occupied by hybrid nanoparticles of Fe3O4-Al2O3 scattered uniformly in 1-Hexanol has been simulated by Galerkin finite element method. The temperature difference between inner cavity and outer wavy surface stirred the heat flux within the bounded domain. The determinants of thermal evolution are classified by porosity alteration, radiation intensity,... 

Total hip arthroplasty (THA) is considered one of the most efficient orthopedic operations. Patients with symptomatic hip osteoarthritis, hip osteonecrosis, congenital hip dysplasia, inflammatory arthritis, and femoral head fracture can benefit from THA through pain relief and functional restoration. Various articles have analyzed acoustic features during broaching and stem insertion. Still, they could not provide a conclusive and clinically usable approach to ensure the success of the surgery. In this study, we aimed to investigate sound characteristics with a musical approach using a chromatic tuner. Surgeries were performed by two experienced orthopedic hip fellowship surgeons via the...