Use Of Magnetic Fluids Research Articles

Use of magnetic fluids in process system for pipe isolations

This paper investigates the use of magnetic fluids known as ferrofluids to act as ad hoc valves within pipe systems to create isolation points for stemming pipe leakages and to halt leakages before they become largescale disasters. The sealing abilities of ferrofluids were proven for microvalves (ID ≤ 1 mm) in hydrostatic experiments and extended to the macroscale applications (ID ≥ 6 mm). Theoretical prediction and magnetic finite element analysis (FEA) were also undertaken to predict the burst pressure, and a comparison of both results against the experimental measurement was made. The up-scale results (10–18 mm ID) indicated that it is feasible to develop a ferrofluid that can be extended to approximate the applicable magnet strength to achieve higher burst pressure. It was concluded that the ferrofluid isolation valves hold potential in macroscale environments for process engineering in favour of a positive isolation.

TECHNOLOGY OF WATER TREATMENT FROM OIL PRODUCTS USING MAGNETIC LIQUIDS FROM INDUSTRIAL WASTE

This article explores new perspectives on the use of magnetic fluids for efficient water treatment of petroleum products. A review of existing technologies and their limitations is provided, emphasizing the need for new approaches. The use of magnetic fluids that are highly selective to petroleum products is investigated. Experimental results show that the modified magnetic fluids effectively remove petroleum products from water, providing high quality treatment. The study also examines the durability and cost-effectiveness of the proposed approach, suggesting its practical application in water treatment plants. The paper provides a valuable contribution to the water treatment field, opening up new opportunities for effective removal of petroleum products and protection of water resources. Aims of the study are to reduce the concentration of petroleum products in wastewater; to develop an effective technology for wastewater treatment from petroleum products using magnetic fluid. Objectives of the work are to study the composition of iron-containing waste; to consider the technology of wastewater treatment from petroleum products; to study the parameters of wastewater treatment from petroleum products.The objects of the study are industrial iron-containing waste, magnetite obtained from waste, as well as magnetic liquid synthesized on the basis of magnetite and wastewater.

Основы построения струйно-капельных оптических систем трехкоординатных измерений напряженностей электрического, магнитного и гравитационного полей методом висящей капли. Часть 1

The article discusses the principle of operation and the main components of jet-drop optical measuring systems (JDOMS) based on the pendant drop method for monitoring electric field strength (EFS), magnetic field (MFS) and gravitational field (GFS). To make a pendant drop sensitive to electric or magnetic fields, it is proposed to charge it electrostatically or to create it from a magnetic fluid, and its mass allows you to feel changes in the gravitational field. The use of magnetic fluids as the basis of a pendant drop is the most multifunctional for measurements of EFS, MFS and GFS. The implementation of the zero measurement method using a pendant drop as a comparison device, a null organ that perceives the difference in the effects of the measured and reference field(s) at the level of quasi-zero three-coordinate displacements, is considered. They are measured by high-precision optical measurement methods. Different variants of modern optical measurement systems are analyzed.

DETERMINATION OF THE PHYSICO-CHEMICAL CHARACTERISTICS OF A MAGNETIC LIQUID IN THE IMPLEMENTATION OF THE METHOD BASED ON AN ELECTROMAGNETIC CONVERTER

A non-contact three-parameter electromagnetic method for measuring magnetic susceptibility κ, electrical conductivity χ, and temperature t of a ferrofluid sample is proposed. Theoretical principles of the operation of the inductive parametric electromagnetic transducer (IPET) with a sample of ferro-fluid are considered. As a result of studies of the universal functions of transformation of the IPET with a sample of the ferro-fluid, the theoretical provisions of the work of the IPET were further developed, which are related to the possibility of estimating the static parameters of the magnetic fluid. Because record of the effect of eddy currents leads to the need to determine three parameters of magnetic fluids with only one IPET, the necessity of using an inductive IPET switching circuit with a ferro-fluid sample, which provides for compensation of interfering external inductance L1 using a compensating capacitance P567 to improve the accuracy of measurements of the physical and chemical parameters of magnetic fluids, has been proved. The operation of the circuit is based on the fact that the eddy EMF excites a magnetic flux in the sample of the magnetic fluid under study, which is added geometrically with the excited magnetic flux from an external source, creating the resulting magnetic flux Ф2t in the sample of the magnetic fluid under study, while the resulting magnetic flux decreases in magnitude and shifts by the phase angle in relation to the excited magnetic flux, all this leads to a change in the components of the signals of the IPET, that is: inductance Lit and resistance Ω2t, which are associated with the physicochemical parameters κ, χ and t of the magnetic fluid sample. In further studies, in order to increase the efficiency of wastewater treatment of a mini-brewery, it is recommended to use a magnetic fluid in complex cleaning methods that involve the use of magnetic fluids in filters for post-treatment of wastewater from food production of acidic and alkaline composition.

К ВОПРОСУ ТЕХНОЛОГИЧНОСТИ ИЗДЕЛИЙ СНИЖЕННОЙ МАССЫ В АВИАЦИОННОЙ И РАКЕТНО- КОСМИЧЕСКОЙ ТЕХНИКЕ, ПОЛУЧЕННЫХ С ПОМОЩЬЮ ДЕГЕНЕРАТИВНОГО ДИЗАЙНА

The paper discusses the features of the design of structures with the use of generative design; the analysis of the software was carried out, taking into account the various industrial man-ufacturability of the design results; formulated technological recommendations for the blank production, as well as for the following ma-chining; for fixing workpieces of complex shape on the machine, it is proposed to use tooling with the use of magnetic fluids.

Enhancing membrane-based soft materials with magnetic reconfiguration events

Adaptive and bioinspired droplet-based materials are built using the droplet interface bilayer (DIB) technique, assembling networks of lipid membranes through adhered microdroplets. The properties of these lipid membranes are linked to the properties of the droplets forming the interface. Consequently, rearranging the relative positions of the droplets within the network will also alter the properties of the lipid membranes formed between them, modifying the transmembrane exchanges between neighboring compartments. In this work, we achieved this through the use of magnetic fluids or ferrofluids selectively dispersed within the droplet-phase of DIB structures. First, the ferrofluid DIB properties are optimized for reconfiguration using a coupled experimental-computational approach, exploring the ideal parameters for droplet manipulation through magnetic fields. Next, these findings are applied towards larger, magnetically-heterogeneous collections of DIBs to investigate magnetically-driven reconfiguration events. Activating electromagnets bordering the DIB networks generates rearrangement events by separating and reforming the interfacial membranes bordering the dispersed magnetic compartments. These findings enable the production of dynamic droplet networks capable of modifying their underlying membranous architecture through magnetic forces.

Rotor-dynamic performance of porous hydrostatic thrust bearing operating under magnetic field

Purpose The porous bearings are commonly used in slider thrust bearings owing to their self-lubricating properties and cost effectiveness as compared to conventional hydrodynamic bearings. The purpose of this paper is to numerically investigate usefulness of porous layer in hydrostatic thrust bearing operating with magnetic fluid. The effect of magnetic field and permeability has been analysed on steady-state (film pressure, film reaction and lubricant flow rate) and rotor-dynamic (stiffness and damping) parameters of bearing. Design/methodology/approach Finite element approach is used to obtain numerical solution of flow governing equations (Magneto-hydrodynamics Reynolds equation, Darcy law and capillary equation) for computing abovementioned performance indices. Finite element method formulation converts elliptical Reynolds equation into set of algebraic equation that are solved using Gauss–Seidel method. Findings It has been reported that porosity has limited but adverse effects on performance parameters of bearing. The adverse effects of porosity can be minimized by using a circular pocket for achieving better steady-state response and an annular/elliptical pocket, for having better rotor-dynamic response. The use of magnetic fluid is found to be substantially enhancing the fluid film reaction (53%) and damping parameters (55%). Practical implications The present work recommends use of circular pocket for achieving better steady-state performance indices. However, annular and elliptical pockets should be preferred, when design criteria for the bearing are better rotor-dynamic performance. Originality/value This study deals with influence of magnetic fluid, porosity and pocket shape on rotor-dynamic performance of externally pressurized thrust bearing. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0289/

Highly Sensitive Fiber‐Optic Intrinsic Electromagnetic Field Sensing

Fiber‐optic sensing is resistant to electromagnetic interference; therefore, electromagnetic field sensing using fiber‐optic sensors is challenging. Herein, the first demonstration of fiber‐optic intrinsic electromagnetic field sensing based on modal interferometry with the highest reported sensitivity is presented (here, to be intrinsic means that the magnetic field interaction occurs only within the optical fiber, where there is no use of magnetic fluids or extrinsic structures). A fused polymer optical fiber (POF) is connected to two silica single‐mode fibers (SMFs) through an UV‐curing resin. Another interferometer with a nonfused POF is also fabricated, and the transmitted spectra of both the interferometers are compared in the presence of an electromagnetic field (0–240 mT). The results show the insensitivity of the nonfused POF interferometer and a mean sensitivity of 16.7 pm mT−1 for the fused POF interferometer, which presents a tenfold increase by changing the fused POF length from 2 to 5 cm, resulting in a sensitivity of 113.5 pm mT−1. The proposed intrinsic electromagnetic field sensor has the potential of measuring magnetic field intensities as low as 45 μT (considering its high sensitivity) with possibility of further increase with small changes in the signal acquisition components.

Actively lubricated hybrid journal bearings based on magnetic fluids for high-precision spindles of machine tools

The research work reported in this article is focused on the use of magnetic fluids as active lubricant for improving the performance of hybrid journal bearings, with application to high-precision machine tools. Prototype design was optimized following numerical computation of Reynolds equation and computational fluid dynamics calculations, in both cases with Herschel–Bulkley model for the magnetorheological fluid. This fluid (LORD Corp. MRF 122-2ED) was experimentally characterized in detail. The improvement of the hydrodynamic effect in journal bearings was demonstrated with 50% higher load capacity and stiffness, mainly at half of shaft eccentricity 0.4 < ε < 0.7. Active hydrostatic lubrication achieved quasi-infinite stiffness within working limits (load and speed), at low frequencies. For high dynamic response, the active lubrication based on magnetorheological valves did not show good response. The feasibility of using magnetic fluids for developing high performance machine tool spindles and the validity of the simulation models was demonstrated experimentally.

Tunable, Sheathless Focusing of Diamagnetic Particles in Ferrofluid Microflows with a Single Set of Overhead Permanent Magnets.

There has been increasing interest in the use of magnetic fluids to manipulate diamagnetic particles in microfluidic devices. Current methods for diamagnetic-particle focusing in magnetic fluids require either a pair of repulsive magnets or a diamagnetic sheath flow. We demonstrate herein a tunable, sheathless focusing of diamagnetic particles in a microchannel ferrofluid flow with a single set of overhead permanent magnets. Particles are focused into a single stream near the bottom wall of a straight rectangular microchannel, where a magnetic-field minimum is formed as a result of the magnetization of the ferrofluid. This focusing can be readily switched off and on by removing and replacing the permanent magnets. More importantly, the particle-focusing position can be tuned by shifting the magnets with respect to the microchannel. We perform a systematic experimental study of the parametric effects of the fluid-particle-channel system on diamagnetic-particle focusing in terms of a defined particle-focusing effectiveness.

Application of the magnetic fluid as a detector for changing the magnetic field

In article the possibility of use of magnetic fluid as a sensitive element for fixing of change of induction of magnetic field in space is considered. Importance of solvable tasks is connected with search of the perspective magnetic substances susceptible to weak magnetic field. The results of a study of the capacitive method for fixing the change in the magnetic field on the basis of a ferromagnetic liquid are presented. The formation of chain structures in the ferrofluid from magnetic particles under the influence of the applied magnetic field leads to a change in the capacitance of the plate condenser. This task has important practical value for development of a magnetosensitive sensor of change of magnetic field.

INFLUENCE OF PAD GEOMETRY MODIFICATION ON THE PERFORMANCE OF THRUST BEARINGS LUBRICATED WITH MAGNETORHEOLOGICAL FLUID

Magnetic fluids belong to the class of controllable materials. The influence of magnetic fields on this type of substance results in a change in its internal structure and an almost immediate change in its rheological properties. The ability to control the rheological characteristics in a very wide range, in combination with the ease of generating and controlling the magnetic field, creates the possibility of using this type of substance in systems with controlled operating parameters. The use of magnetic fluids in bearings may allow the design of some types of bearings to be simplified and enable efficient, fast, and precise control of the system operation, with a much shorter response time and higher stiffness than is the case with conventional sliding friction bearings. The paper presents the results of experimental tests carried out on a laboratory stand designed for thrust bearings lubricated with magnetic fluids. The analyses carried out concerned the determination of how the pad surface modification of the slide bearing, lubricated with magnetorheological fluids, influences the system performance parameters.

Seals Based on Magnetic Fluids for High Precision Spindles of Machine Tools

The research work reported in this paper is focused on the use of magnetic fluids as active elements in seals for improving sealing capacity and minimizing friction torque, with application to the spindles of high precision machine tools. The prototype design was optimized following numerical computation of the magnetic field in the rings of the seal. Two magnetic fluids were analyzed for their use in the seals: a ferrofluid and magnetorheological fluid. The sealing capacity of the MRF based seals was higher than 45 kPa per ring, but the friction of the seal in the bearing was 8 N·m, too large for the use in precision spindles of machine tools because of the energy consumption and heat generation. The ferrofluid seal achieved sealing capacity around 9 kPa per ring, good enough to be used in the spindles of machine tools, with a friction 0.25 N·m and low energy consumption. The feasibility of using ferrofluids for developing high performance seals for high precision spindles and the validity of the simulation models has been demonstrated experimentally.

Detection of the change of a magnetic field in the environment by magnetic fluid

The experimental results of the magnetic field sensor based on various materials are presented. In article the possibility of use of magnetic fluid as a sensitive element of the magnetic field sensor is considered. The importance of current tasks deals with the search of the perspective magnetic substances susceptible to weak magnetic field. The operation principle of the sensor is based on change in the capacity of the condenser with magnetic active medium caused by the magnetic field. The complex organization of magnetic particles into chain aggregates was considered. The principle of measuring the condenser capacity is described. The experimental results are promising for future application.

Design of science laboratory sessions with magnetic fluids

Application of new achievements in science and technology to the physics laboratory sessions can ensure the advancement of physics education. One particular example of the technologies giving new opportunities in the design of physics laboratory works is the magnetic fluid. We describe the laboratory works within the scope of the general physic course for the undergraduate students. Principal feature of the laboratories presented is the use of magnetic fluids. It makes possible to design some creative laboratory works, which can help to develop skills in performing scientific experiments and to increase the understanding of the physical concepts. The sample consists of 120 third-grade university students from the Department of General and Theoretical Physics in the North Caucasus Federal University in Stavropol, Russia. These laboratories arouse students’ interest and contribute to the achievement of high quality of learning outcomes. We also show that such laboratories engage students’ interest in the scientific research work.

Antitumor effect of free rhodium (II) citrate and rhodium (II) citrate-loaded maghemite nanoparticles on mice bearing breast cancer: a systemic toxicity assay.

Breast cancer is one of the most prevalent cancer types among women. The use of magnetic fluids for specific delivery of drugs represents an attractive platform for chemotherapy. In our previous studies, it was demonstrated that maghemite nanoparticles coated with rhodium (II) citrate (Magh-Rh2Cit) induced in vitro cytotoxicity and in vivo antitumor activity, followed by intratumoral administration in breast carcinoma cells. In this study, our aim was to follow intravenous treatment to evaluate the systemic antitumor activity and toxicity induced by these formulations in Balb/c mice bearing orthotopic 4T1 breast carcinoma. Female Balb/c mice were evaluated with regard to toxicity of intravenous treatments through analyses of hemogram, serum levels of alanine aminotransferase, iron, and creatinine and liver, kidney, and lung histology. The antitumor activity of rhodium (II) citrate (Rh2Cit), Magh-Rh2Cit, and maghemite nanoparticles coated with citrate (Magh-Cit), used as control, was evaluated by tumor volume reduction, histology, and morphometric analysis. Magh-Rh2Cit and Magh-Cit promoted a significant decrease in tumor area, and no experimental groups presented hematotoxic effects or increased levels of serum ALT and creatinine. This observation was corroborated by the histopathological examination of the liver and kidney of mice. Furthermore, the presence of nanoparticles was verified in lung tissue with no morphological changes, supporting the idea that our nanoformulations did not induce toxicity effects. No studies about the systemic action of rhodium (II) citrate-loaded maghemite nanoparticles have been carried out, making this report a suitable starting point for exploring the therapeutic potential of these compounds in treating breast cancer.

DYNAMIC CHARACTERISTICS OF MAGNETIC FLUID BASED SLIDING BEARINGS

The dynamic behaviors of magnetic fluid-lubricated slider bearings have been investigated in this paper. For the slider bearing with an inclined film profile, the use of magnetic fluids as lubricants is found to provide an increase in the load carrying capacity, and the stiffness and damping coefficients as compared to the case of a conventional viscous fluid. The dynamic characteristics of slider bearings are improved by using magnetic fluid lubri-cants together with the application of magnetic fields. DOI: http://dx.doi.org/10.5755/j01.mech.19.5.5535

Study of slip velocity effect on performance of magnetic fluid flow

The use of magnetic fluids has led to the development of many new energy devices and instruments. Magnetically cooled high fidelity speakers, computer disc drives and semiconductors are already in commercially use. Magnetic fluids are prepared by suspending ferromagnetic grains in non-magnetic, non-conducting liquids such as diesters, kerosene, hydrocarbons and fluorocarbons. Among various applications in engineering, most important are those of the possibility of collecting and holding firmly small quantities of such fluids in regions with highly focused magnetic fields. A theoretical model of magnetic fluid based porous-pivoted slider bearing with slip velocity is considered to study effect of surface roughness on the performance of fluid. Generalized form for surface roughness characterized by stochastic random variable with non-zero mean, variance and skewness is used to define bearing surface. Load capacity is evaluated in terms of magnetic, permeability, slip and surface roughness parameters. Numerical and graphical behavior of load capacity based on magnetic, permeability, slip and surface roughness parameters is also studied. Minimization of slip parameter and permeability parameter is discussed for the possible increase in the load capacity.

Magnetic excitation of oscillation of magnetically levitated liquid column

Magnetic levitation of molten metal can be simulated even in weak magnetic field by use of magnetic fluid as a surrounding fluid. The levitated liquid column is desirable to be stable, but it can be deformed or displaced from the equilibrium position. In the present research the disturbance is magnet ically given to the liquid column and the excited oscillatio n is studied experimentally and analytically. The liquid column has inherent natural frequencies, and a kind of resonance occurs at these frequencies, which will lead to the instability.

Ferrofluidic Pumps: A Valuable Implementation Without Moving Parts

The use of magnetic fluids in transducers is of great interest due to the possibility of implementing highly reliable and reconfigurable sensors and actuators. Examples of ferrofluidic transducers are available in several contexts from the detection of inertial quantities to assorted bioapplications. This paper addresses a novel architecture implementing a ferrofluidic pump intended for several purposes, including fluid control in bioapplications. The proposed architecture can be used to realize discrete and integrated pumps. The strategies that led to the implementation of the device are highlighted, along with theoretical considerations. The real prototype developed and the setup adopted for its characterization are also presented, along with experiments aimed at estimating the performance of the device.