Papers by Keyword: Ferrofluid

Abstract: This study investigates the structural response of blank-holders (BHs) equipped with spatially distributed magnetorheological (MR) actuators for adaptive deep drawing. While MR actuators provide fast, independent, and high-resolution force modulation, their effectiveness depends critically on the BH’s ability to transmit spatially differentiated loads without excessive diffusion or unrealistic stress localization. The relationships between BH stiffness, actuator spacing, and pressure localization at the sheet interface remain only partially understood, limiting the implementation of distributed blank-holding strategies. To address this gap, a comprehensive finite element (FE) framework is developed, combining a full closed-cup deep-drawing model with a complementary simplified configuration that isolates local deformation mechanisms under single-actuator loading. Parametric analyses examine the influence of BH thickness, local actuator force, and actuator spacing on stress distribution, localization radius, and overlap between adjacent load paths. Results show that BH thickness is the dominant factor governing spatial resolution: thinner BHs enable sharp pressure localization, whereas thicker ones diffuse local loads and suppress stress peaks. The spacing between actuators must therefore be selected as a function of BH stiffness to avoid stress-free regions while preserving distinct pressure footprints. For the reference industrial configuration (60 mm BH thickness), an actuator spacing of approximately 150 mm achieves the optimal compromise between localization capability and continuous sheet support. The proposed framework establishes quantitative design criteria for BH geometries compatible with MR-based adaptive forming and supports the development of next-generation blank-holding systems offering enhanced process stability, reduced scrap, and improved material-flow control.

Abstract: Local hyperthermia therapy is one of the cancer treatments by implementing heat from a temperature of 41-45°C on cancer cells. This method is believed to reduce the risk of normal cells around the cancer cells from dying. The form of hyperthermia therapy itself is in ferrofluid. During its development, superparamagnetic nanoparticles of iron oxide have attracted various studies because of their good magnetic properties and good biocompatibility. However, the poor particle interactions and their tendency to aggregation make coatings on superparamagnetic necessary. Therefore, silica coating on the superparamagnetic surface is carried out to reduce the risk of aggregation and increase the biocompatibility of the material. Polyethylene glycol functionalization was also applied to improve the biocompatibility of the material, as well as being a carrier for ferrofluid. The test was carried out using the magnetite co-precipitation synthesis method and the formation of a sol-gel silica coating. Variations applied in this experiment are the effects of TEOS concentration as a source of silica and the ratio of particles to PEG. The addition of silica was proven to increase the value of the magnetic moment to 51.55 emu/g. The addition of TEOS as a source of silica in iron (III) nanoparticles has an effect on increasing the magnetic attraction, decreasing the surface tension value, reducing particle size, and decreasing the SAR value. Functionalization of polyethylene glycol has the effect of reducing the magnetic moment, increasing and decreasing hydrophobicity, increasing the surface tension value, and reducing the particle size of iron (III) oxide nanoparticles. This shows that magnetic nanoparticles coated with silica with polyethylene glycol functionalization are proven to generate heat when given AC current with the SAR value and the highest temperature is found in iron (III) oxide which gets 3ml silica coating with a PEG ratio of 2:5 at a temperature of 32.2°C. and SAR value of 87.63 W/mg

Abstract: The current investigation aims to synthesize MgFe₂O₄ magnetic nanoparticle and measure the thermal conductivity of MgFe₂O₄ ferrofluid. Prepared MgFe₂O₄ nanoparticle's structural characterization, the concentration of constituents, and surface morphology were analyzed using XRD, EDAX, and TEM respectively. This study also analyses the influence of magnetic flux on the thermal conductivity of MgFe₂O₄/ EG: H₂O (60:40) based ferrofluids formed by the two-step method. Thermal conductivity of ferrofluid measured at different volume fractions (ranging from 0.01% to 0.20%) show that thermal conductivity augmented with an escalation in volume fraction and the highest enhancement of 10.32% was reached at 0.20% volume fraction. Results indicate that the applied magnetic flux improves the thermal conductivity of ferrofluid from 10.32% to 14.75% at 0.20% volume fraction and 350 Gauss Magnetic flux.

Abstract: In this paper we have developed a simple and inexpensive method to fabricate cilia-like silicone rubber-ferrofluid composite cantilever beams. The technique described can generate highly reproducible arrays of these microcantilevers ranging from 1 mm to 0.4 mm in diameter. We use a laser cutter to create moulds for the cantilevers making it a low cost and reliable process. The iron particles from the ferrofluid can uniformly dispersed, randomly arranged or isolated on the tip of the cantilever. Cantilevers with 400 μm diameter and up to 10 mm length are tested with low magnetic field of 15mT. We obtained maximum deflection of 82.5^o at 44 mT magnetic field.

Abstract: The project presents the use of laser and magnetic nanoparticles like iron oxide (Fe₃O₄) in heavy metal detection in water. In this method, metal Nanomagnets particles result in a magnetic reagent for the rapid removal of heavy metals from solutions or water of magnitude to concentration 0.25wt%. This can be done by measuring the magneto-optical parameters (as a hysteric loop) of the solution as an indication of the change in concentrations of the detected heavy metal. The samples used in this work using the Tigris River water that supported from al-Wathba lab. water projects of the Baghdad water directorate at Baghdad-Iraq. Putting here a study of the effect of graphene and metal oxide such as cobalt and nickel which doped the ferrofluid (iron oxide) /polymer/water (Tigris river water) composite on the magneto-optical properties. The graphene adding had the best result in low threshold magnetic field which was 67mGauss, give the motive to use it in fast sensing and detecting of heavy metal in Tigris river water.

Abstract: This study presents a numerical investigation on the magnetohydrodynamic (MHD) stagnation point flow of a ferrofluid with Newtonian heating. The black oxide of iron, magnetite (Fe₃O₄) which acts as magnetic materials and water as a base fluid are considered. The two dimensional stagnation point flow of cold ferrofluid against a hot wall under the influence of the uniform magnetic field of strength is located some distance behind the stagnation point. The effect of magnetic and volume fraction on the velocity and temperature boundary layer profiles are obtained through the formulated governing equations. The governing equations which are in the form of dimensional non-linear partial differential equations are reduced to dimensionless non-linear ordinary differential equations by using appropriate similarity transformation. Then, they are solved numerically by using the Keller-box method which is programmed in the Matlab software. It is found that the cold fluid moves towards the magnetic source that is close to the hot wall. Hence, leads to the better cooling rate and enhances the heat transfer rate. Meanwhile, an increase of the magnetite nanoparticles volume fraction, increases the ferrofluid capabilities in thermal conductivity and consequently enhances the heat transfer.

Abstract: The objective of this study is numerically to investigate the heat transfer suppression characteristics of the ferrofluid with the various magnetic field intensities. In order to analyze the heat transfer suppression characteristics of the ferrofluid, the temperature characteristics and average Nusselt numbers of the ferrofluid were considered with variation of the magnetic field intensity. The magnetic field intensity ranged from 0 to 30000 A/m in order to analyze the effect of the magnetic field intensity on the insulation performance of the ferrofluid. The governing equations for mass, motion, momentum, energy, magnetization and Maxwell are used for the numerical analysis of the ferrofluid. The GSMAC method was used to solve the equations. The average temperatures of the ferrofluid at left cooled area were decreased with the increase of the magnetic field intensities. The average Nusselt numbers of the ferrofluid at the hot side with the magnetic field intensities of 10000 A/m, 20000 A/m and 30000 A/m were 43.7%, 61.4% and 63.8% lower than those at the magnetic field intensity of 0 A/m, respectively. The average Nusselt numbers of the ferrofluid at the cold side with the magnetic field intensities of 10000 A/m, 20000 A/m and 30000 A/m were 50.5%, 79.7% and 83.3% lower than those at the magnetic field intensity of 0 A/m, respectively. The heat transfer characteristics of the ferrofluid were suppressed under strong magnetic field intensity. As a result, the ferrofluid could be considered to improve the insulation performance of thermal storage tank.

Abstract: Large amount of crude oil remains in the reservoir due to the poor sweep and displacement efficiency after displacing fluid injection. To remediate this effect, a thicker displacing fluid is used to reduce viscous fingering for a more stable flood front. A ferrofluid is a suitable candidate due to the tunable viscosity profile when subjected to a magnetic field [1]. In this work, the ability of cobalt substituted magnetite ferrofluid to improve incremental recovery after waterflooding has been investigated via sand pack flooding. Prior to sand pack flooding, structural and magnetic properties of cobalt substituted magnetite nanoparticles were characterized via XRD, FESEM and VSM. Viscosity tests with field strength variation from 0 to 66.88 mT have shown a significant dependency of the ferrofluid’s viscosity on the applied field strength. 6-fold increment of viscosity was recorded when magnetic field strength changes from 19.5 to 66.88 mT. During sand pack flooding, 7.20% of incremental oil was obtained with the ferrofluid injection, even without the presence of a magnetic field. When subjected to a magnetic field, 12.93% and 15.83% of the incremental oil was obtained at 19.5 and 66.88 mT, respectively. It is proven that increase of ferrofluid viscosity with magnetic field strength results in higher incremental recovery. Improved sweep and displacement efficiency has been achieved by injecting the ferrofluid into the oil reservoir.

Abstract: This study numerically investigates the mixed convection of ferrofluids in a partially heated lid driven square enclosure. The heater is located to the left vertical wall and the right vertical wall is kept at constant lower temperature while other walls of the cavity are assumed to be adiabatic. The governing equations are solved with Galerkin weighted residual finite element method. The influence of the Richardson number (between 0.01 and 100), heater location (between 0.25 H and 0.75H), strength of the magnetic dipole (between 0 and 4), and horizontal location of the magnetic dipole source (between-2H and-0.5H) on the fluid flow and heat transfer are numerically investigated. It is found that local and averaged heat transfer deteriorates with increasing values of Richardson number and magnetic dipole strength. The flow field and thermal characteristics are sensitive to the magnetic dipole source strength and its position and heater location.

Abstract: In this work, the non-linear optical properties (nonlinear refractive index , nonlinear absorption coefficient ) for different samples of water based Ferrofluids have been presented and studied by aid of z-scan technique. These liquids have different diameters of nano-particle suspensions. The difference in diameter leads to higher absorption ; bigger radius leads to higher nonlinear coefficient and nonlinear refractive index.