scholarly journals Remotely Self-Healable, Shapeable and pH-Sensitive Dual Cross-Linked Polysaccharide Hydrogels with Fast Response to Magnetic Field

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1271
Author(s):  
Andrey V. Shibaev ◽  
Maria E. Smirnova ◽  
Darya E. Kessel ◽  
Sergey A. Bedin ◽  
Irina V. Razumovskaya ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Cobalt Ferrite ◽  
Fast Response ◽  
Ferrite Nanoparticles ◽  
Polymer Chains ◽  
Self Healing ◽  
Cobalt Ferrite Nanoparticles ◽  
Hydroxypropyl Guar ◽  
Cross Links ◽  
The Magnetic Field

The development of actuators with remote control is important for the construction of devices for soft robotics. The present paper describes a responsive hydrogel of nontoxic, biocompatible, and biodegradable polymer carboxymethyl hydroxypropyl guar with dynamic covalent cross-links and embedded cobalt ferrite nanoparticles. The nanoparticles significantly enhance the mechanical properties of the gel, acting as additional multifunctional non-covalent linkages between the polymer chains. High magnetization of the cobalt ferrite nanoparticles provides to the gel a strong responsiveness to the magnetic field, even at rather small content of nanoparticles. It is demonstrated that labile cross-links in the polymer matrix impart to the hydrogel the ability of self-healing and reshaping as well as a fast response to the magnetic field. In addition, the gel shows pronounced pH sensitivity due to pH-cleavable cross-links. The possibility to use the multiresponsive gel as a magnetic-field-triggered actuator is demonstrated.

scholarly journals Cobalt Ferrite Nanoparticles: An Innovative Approach for Enhanced Oil Recovery Application

2012 ◽  
Vol 17 ◽  
pp. 115-126 ◽  
Author(s):  
Noorhana Yahya ◽  
Muhammad Kashif ◽  
Nadeem Nasir ◽  
Majid Niaz Akhtar ◽  
Noorasikin Mohd Yusof
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Cobalt Ferrite ◽  
Ferrite Nanoparticles ◽  
Cofe2o4 Nanoparticles ◽  
Cobalt Ferrite Nanoparticles ◽  
The Magnetic Field

This Paper Describes the Synthesis of Cobalt Ferrite (CoFe2O4) Nanoparticles and their Application in Enhanced Oil Recovery. Cobalt Ferrite (CoFe2O4) Nanoparticles Were Used as Ferrite Magnetic Feeders with Antenna to Improve the Magnetic Field Strength and Cobalt Ferrite Nanofluid to Improve Oil Recovery. Cobalt Ferrite (CoFe2O4) Nanoparticles Were Synthesized by Sol-Gel Method. these Nanoparticles Were then Characterized by Using X-Ray Diffractometer (XRD) and Field Emission Scanning Electron Microscope (FESEM). Cobalt Ferrite Nanoparticles Annealed at 600oC, the Particle Size Is 51.17nm and 26nm as Determined by XRD and FESEM, Respectively while for the Sample Annealed at 800oC, the Particle Size Is 62nm as Determined by XRD and 60 Nm as Determined by FESEM. Magnetic Measurement Results Show that Initial Permeability of Cobalt Ferrite Powder Increased and Relative Loss Factor Decreased at High Frequency. in Order to Improve the Oil Recovery, Nanoparticles Were Used in Two Different Experiments. in the First Experiment, Nanoparticles Were Used as Magnetic Feeders with an Antenna to Improve the Magnetic Field Strength. in the Second Experiment, Nanoparticles Were Used as Nanofluids. Results Show that the Antenna with Magnetic Feeders Increases the Magnetic Field Strength by 0.94% as Compared to Antenna without Magnetic Feeders in the Water, and by 5.90% in the Air. Magnitude versus Offset (MVO) Study of Antenna with Magnetic Feeders Shows an Increase in Magnetic Field Strength of 275% as Compared to Antenna without Magnetic Feeders. it Is Found that Antenna with Magnetic Feeders Was Able to Recover 29.50% and 20.82% of Original Oil in Place (OOIP) in Core Rock Samples A-1 and A-2 Respectively. the Use of Cobalt Ferrite Nanoparticles as a Nanofluid with Electromagnetic Waves Yielded a Higher Recovery of Residual Oil in Place (ROIP) which Is 31.58% as Compared to 8.70% when it Was Used as Nanofluid Alone. it Is Investigated that due to Absorption of Electromagnetic Waves by Cobalt Ferrite Nanoparticles the Oil Viscosity Reduces which Increase the Oil Recovery. it Can Be Concluded that the Synthesised Cobalt Ferrite (CoFe2O4) Nanoparticles Can Be Potentially Used for Enhanced Oil Recovery in Future.

scholarly journals Experimental Investigation of Thermal Conductivity and Effusivity of Ferrite Based Nanofluids under Magnetic Field

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Ashok K. Singh ◽  
Vijay S. Raykar
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Cobalt Ferrite ◽  
Volume Fraction ◽  
High Volume ◽  
Ferrite Nanoparticles ◽  
Field Direction ◽  
Cobalt Ferrite Nanoparticles ◽  
Positive Variation ◽  
Microwave Assisted Method

We investigate the effect of magnetic field (H) on the thermal conductivity (λ) and effusivity (ε) of cobalt ferrite based nanofluids having different concentrations (ϕ). Cobalt ferrite nanoparticles (NPs) have been synthesized using the microwave assisted method. At high volume fraction of cobalt ferrite nanoparticles in water (ϕ > 0), both thermal parameters have been found to be suppressed relative to ϕ and λ of water in the absence of H. However, it is seen that percentage values of the effusivity in perpendicular field direction show negative to positive variation, and thermal conductivity in parallel field direction shows negative to zero variation.

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