Effect of the non-electrically conductive spindle on the viscosity measurements of nanofluids subjected to the magnetic field

The viscosity measurements of magnetic nanofluid subjected to the magnetic field are indispensable in various heat transfer studies. Intention of the present discussion is to critically analyze the magnetic field's influence on the working of two viscometers; a Glass capillary viscometer and a DV-E Brookfield viscometer. The novelty of the present study is in the identification of the underlying reason for the massive escalation in viscosity when the magnetic nanofluid is subjected to magnetic field and rectification of the error caused. The stainless-steel spindle in the viscometer is replaced with a non-electrically and non-magnetically conductive nylon spindle to rectify the error. The dynamic viscosity of magnesium ferrite nanofluid of different volume fractions at a temperature of 25 °C in the occurrence of magnetic field was measured. The viscosity of magnetic nanofluid measured using DV-E Brookfield viscometer escalated to a maximum of 725% over the same measured using glass capillary viscometer with the magnetic field application. The application of the nylon spindle in the viscometer eliminates the error caused due to the eddy current formation in the spindle. Therefore, this study recommends using viscometers with non-electrically and non-magnetically conductive spindles for accuracy while measuring the viscosity of magnetic fluids.The Karunya Institute of Technology and Sciences, India, through the Karunya Short Term Research Grant.http://www.elsevier.com/locate/colsurfa2022-08-05hj2022Mechanical and Aeronautical Engineerin

Turbulent magnetohydrodynamic natural convection in a heat pipe-assisted cavity using disk-shaped magnesium ferrite nanoparticles

The prospect of altering the thermophysical properties of ferrofluid with an influence of magnetic field leads to improving natural convection in various heat transfer systems. This investigation principally focuses on the studies of electromagnetism-based turbulent natural convection heat transfer of low-density disk-shaped magnesium ferrite/water-based ferrofluid, filled in a novel heat pipe-assisted cubical cavity at various volume fractions. Two flat plate heat pipes were used to maintain temperature differences in the cavity. To advance the buoyancy of the working fluid inside the cavity, deliberately low-density ferrofluid containing disk-shaped particles was formulated using the hydrothermal method. The temperature difference between the two heat pipe-assisted vertical walls was sustained with four distinct temperature ranges from 10 to 25 °C. The ferrofluid filled in the cavity was then subjected to magnetic field ranging from 0 to 350 G to understand the thermomagnetic convection effects on heat transfer. The optimal volume fraction of ferrofluid for maximum heat transfer was found to be 0.05% at a wall temperature difference of 25 °C, owing to 23.51% improvement in average heat transfer coefficient along with 33.37% improvement in average Nusselt number when compared to water. With the application of a magnetic field of 350 G, the average heat transfer coefficient was further enhanced by 10.11%, and the average Nusselt number improved by 6.28% for 0.05% volume fraction in comparison to the condition where no magnetic field was applied.https://link.springer.com/journal/13204hj2023Mechanical and Aeronautical Engineerin

Morphological effects on natural convection heat transfer of magnesium ferrite ferrofluid

This investigation intends to analyze the influence of nanoparticles morphology on the magnetic flux dependent thermo-physical properties and magnetohydrodynamic free convection heat transfer performance of water-based magnesium ferrite ferrofluid under various volume fractions. The thermo-physical parameters of the ferrofluid suspended with cube shaped particles are examined at 25 °C using KD2 pro thermal analyzer, Ostwald viscometer and specific gravity bottle under magnetic flux. The free convection heat transfer is obtained using heat pipes assisted cubical enclosure. Without the influence of magnetic flux, the thermal conductivity of the ferrofluid was improved by a maximum of 12.75% at a volume fraction of 0.15%. At the same time, the maximum viscosity and density were raised by 32.92% and 6.11% at a volume fraction of 0.20% in comparison with water. Under the influence of 350 Gauss, thermal conductivity, and viscosity of ferrofluid enhanced by 21.81% and 37.41% while the density decreased by 4.91%. It was revealed that the addition of cube-shaped magnesium ferrite particles in ferrofluid improved the thermo-physical properties. The optimum concentration for maximum heat transfer is reduced to 0.025% with the use of cube shaped particles compared to other types of nanoparticles reported in previous studies.https://www.tandfonline.com/loi/uhte202024-06-27hj2024Mechanical and Aeronautical EngineeringNon

Magnetic hydroxyapatite nanomaterial–cyclodextrin tethered polymer hybrids as anticancer drug carriers

Osteosarcoma, the most common bone cancer, leads to a poor survival rate of patients. Drug targeting employing hydroxyapatite (HAp)-based nanocarriers represents a fascinating choice for non-invasive treatment of osteosarcoma. Herein, we report strontium-doped (Sr-HAp) and iron- and strontium-co-doped (Sr,Fe-HAp) hydroxyapatite nanoparticles as novel materials that deliver doxorubicin to bone cancer cells. A platinum-complexed and cyclodextrin-functionalized chitosan derivative is utilized to coat the NPs. Sr-HAp (aspect ratio ∼20) and Sr,Fe-HAp (aspect ratio ∼3) nanoparticles are formed as nanowhiskers and nanorods, respectively, as revealed by transmission electron microscopy. Strontium ferrite NPs are synthesized and their properties are compared with those of the Sr/Sr,Fe-doped HAp NPs. These ferrite NPs show ferromagnetic behavior, as opposed to Sr-HAp and Sr,Fe-HAp. The latter two respectively display paramagnetic and superparamagnetic behaviors. The loading percentage of the anticancer drug, Doxorubicin (Dox), in the nanocarriers is high and the release of Dox is sustained at physiological pH. The Dox-loaded nanocarriers are tested for their in vitro cytotoxicity against lung, cervical, liver, and bone cancer cell lines. In general, the efficacy of Dox is not diminished on loading in the nanocarriers. In addition, the Dox-carriers demonstrate a time- and dose-dependent cytotoxicity. The efficacy is enhanced in the case of Dox-loaded carriers on MG-63 (osteosarcoma) cell lines. The anticancer activity is tested in vivo on both male and female albino mice. Enhanced chemotherapeutic potential is observed for Dox-loaded Sr,Fe-HAp in a metastatic model of MG-63. The platinum derivative polymer possesses its own therapeutic effect and contributes to the general activity. The novel polymer-HAp nanohybrid represents an effective nanocarrier for the treatment of osteosarcoma