Magnetic Rods Research Articles

Study of magnetic-responsive nanoparticle on the membrane surface as a membrane antifouling surface coating

This study aims to form a dynamic layer of the magnetic protective layer (f- Fe3O4/PDDA) on a surface of cellulose acetate (CA) membrane to prevent direct membrane-foulant interactions during an ultrafiltration process. To this end, Fe3O4 nanoparticles with an approximate size of 151.8 ± 8.2 nm were spin-coated on the surface of CA membrane to provide magneto-induced actuation motions of the magnetic nano-colloid in 3-dimensional space, with the help of an external magnetic field (magnetic rod). ATR-FTIR, QCM-D, and cross-flow filtration of this magnetic-responsive membrane were investigated to determine its influences on surface fouling by humic acid solutions. In fact, ATR-FTIR and QCM-D analyses have demonstrated a minimum membrane fouling for the magnetic-responsive membrane that operated under the influence of an oscillating magnetic field. Cross-flow filtration results showed a practically higher permeation (retaining 54% of the initial flux at its steady-flow) and humic acid rejection (more than 85%) in the presence of an oscillating magnetic field compared to its performance in the absence of an oscillating magnetic field. Findings from this magnetically responsive membranes could represent a new class of fouling-resistant membrane.

Improving Induction Crucible Furnaces

The main deficiencies of existing induction crucible furnaces are associated with elevated wall thickness of the lined crucible, the tubular copper single-layer inductor (with internal cooling by conditioned water), and the absence or presence of surrounding vertical I-shaped composite metal rods, forming a discrete ferromagnetic screen. The first deficiency is that much of the working electromagnetic flux Φwo is wasted, since it passes along the crucible lining, which is not electrically conducting, rather than along the furnace charge. Only 38.5–57.0% of Φwo is utilized. The second deficiency is associated with the high cost and laboriousness of manufacturing the inductor turns from special copper pipe, which vibrates at double frequency. That creates noise and weakens the furnace structure. Such inductors are characterized by low electrical efficiency and high costs of preparation and cooling of the conditioned water in systems of area several times greater than the furnace itself. The consequence of the third deficiency is that much of the electromagnetic scattering flux Φsc is not involved in heating the batch and the melt but instead heats the electrically conducting elements of the furnace, including the magnetic rods that surround the inductor. Because of the poor utilization of the total flux Φ generated by the inductor, the efficiency is decreased practically to 19–30%, while the power factor falls to 0.03–0.10, with increase in the energy consumption. To minimize or eliminate the deficiencies, three modifications are proposed: decrease in the sleeve’s wall thickness, with simultaneous strengthening by installing a cylindrical shell between the crucible and the inductor; introduction of a magnetic ring around the inductor; and the use of a single-wire or multicore inductor, instead of a tubular inductor. The combination of a cylindrical shell, a magnetic ring, and upper and lower housing plates permits the formation of a closed annular cavity where the inductor may be placed, with cooling of the inductor and the magnetic ring by circulating fluid. On the basis of research, a new design of an induction crucible furnace with a wire inductor and a composite magnetic ring (magnetic core) has been developed at Polzunov Altai State Technical University, tested, and patented. In experiments, the efficiency of the proposed structural elements is confirmed, indicating that the design merits further study.

Interfacial Fourier transform shear rheometry of complex fluid interfaces

Nonlinear rheometry of interfaces is very challenging because of the limits of current day instrumentation and the intricate coupling of flows at interfaces and in the bulk. The use of time periodic flows may constitute a first step in addressing this issue. Fourier transform rheology (FTR) measurements with quasi-monolayers at the air-water interface are used in order to assess the suitability of the different devices to investigate nonlinear interfacial shear viscoelasticity. The probe material was a poly (methyl methacrylate) forming a soft glassy interface, whereas complementary measurements were performed with a polystyrene latex suspension forming a predominantly viscous interface at intermediate surface coverages. The obtained data with the magnetic rod rheometer (ISR) were compared against those obtained with the bicone and the double wall ring geometries attached to standard rotational rheometers. In particular, an unexpected appearance of even in addition to odd harmonics is discussed in terms of flow field asymmetry.

The effectiveness of dual-magnetic controlled growth rods in the distraction period in the treatment of early-onset scoliosis

Aim: The aim of the present study is to evaluate our dual magnetic controlled growing rod practices in early-onset scoliosis in terms of curve correction and control, and the effect on sagittal and coronal balance until definitive fusion surgery.Material and Methods: Ten patients under 10 years of age who had a major curvature of more than 30 degrees with the diagnosis of early-onset scoliosis and were operated on between 2014-2018 were included in the study. The mean age of the patients was 8.8 years (range, 7-10) and the mean follow-up was 26 months (range, 12-36). Magnetic rod was distracted at between 12-week intervals with a mean distraction per patient of 8.2 times (range, 6-12). Cobb angle, T1-T12 kyphosis angle, T1-S1 lengths, the coronal and sagittal balance were all evaluated.Results: The mean pre-operative, post-operative and last follow-up Cobb angle results were 54°±16 (range, 40-88), 28°±14 (range, 10-55) and 30°±16 (range, 10-59), respectively (p0.05). The mean pre-operative, post-operative and last follow-up T1-S1 lengths were 276 ± 53 mm (range, 170-365), 309±49 mm (range, 207-385) and 348±55 mm (range, 227-405), respectively (p0.05). The mean pre-operative, post-operative and last follow-up kyphosis angle was 49°±18 (range, 21-74), 22°±8 (range, 10-39) and 21°±5 (range, 12-28), respectively (p0.05). No complications were observed during the operation, outpatient distraction and at the last follow-up. Conclusion: In our short-term follow-up, the dual-magnetic rod technique allowed the spinal growth and control of scoliosis and lengthening.

Dynamic Measurements with the Bicone Interfacial Shear Rheometer: Numerical Bench-Marking of Flow Field-Based Data Processing

Flow field-based methods are becoming increasingly popular for the analysis of interfacial shear rheology data. Such methods take properly into account the subphase drag by solving the Navier–Stokes equations for the bulk phase flows, together with the Boussinesq–Scriven boundary condition at the fluid–fluid interface and the probe equation of motion. Such methods have been successfully implemented on the double wall-ring (DWR), the magnetic rod (MR), and the bicone interfacial shear rheometers. However, a study of the errors introduced directly by the numerical processing is still lacking. Here, we report on a study of the errors introduced exclusively by the numerical procedure corresponding to the bicone geometry at an air–water interface. In our study, we set an input value of the complex interfacial viscosity, and we numerically obtained the corresponding flow field and the complex amplitude ratio for the probe motion. Then, we used the standard iterative procedure to obtain the calculated complex viscosity value. A detailed comparison of the set and calculated complex viscosity values was made in wide ranges of the three parameters herein used, namely the real and imaginary parts of the complex interfacial viscosity and the frequency. The observed discrepancies yield a detailed landscape of the numerically-introduced errors.

Development of a scanning probe microscopy integrated atomic layer deposition system for in situ successive monitoring of thin film growth

A dual chamber system integrated with atomic layer deposition (ALD) and atomic force microscopy (AFM) was developed for the successive monitoring of nanoparticles to thin film growth process. The samples were fabricated in the ALD chamber. A magnetic transmission rod enabled sample transferring between the ALD and the AFM test chambers without breaking the vacuum, avoiding possible surface morphology change when frequently varying the growth condition and oxidation under ambient condition. The sample transmission also avoids deposition and contamination on the AFM tip during the successive testing. The sample stage has machined a group of accurate location pinholes, ensuring the 10 μm2 measurement consistency. As a demonstration, the platinum thin films with different thickness were fabricated by varying ALD cycles. The surface morphology was monitored successively during the deposition. Under vacuum with controlled oxygen partial pressure, the aging and sintering phenomenon of particles has been studied in the AFM testing chamber after high temperature treatment. The integrated AFM/ALD instrument is potentially a powerful system for monitoring the thin film preparation and characterization.

Can You Stall a Baclofen Pump During a Magnetic Rod Lengthening?

Introduction Baclofen pumps are susceptible to magnetic forces because of the internal drug delivery mechanism. Magnetically controlled growing rods, sometimes implanted in the patients who have pumps, are lengthened using a device that generates a magnetic field. No previous study has determined if the external remote controller (ERC) can stall a baclofen pump during a rod lengthening. Methods Two baclofen pumps were placed in proximity to the ERC while it generated a magnetic field. This process was repeated with variations in the distance between pump and ERC, speed (dose) of the pump, lengthening time, and position of the ERC relative to the pump. The presence or absence of a stall was recorded. Results To stall a baclofen pump, the ERC needed to be running consistently for at least 30 mm of lengthening. The pump would not stall if it was >1 cm away from the ERC. The pump was more likely to stall if it was positioned in front of or behind the magnetic field, as opposed to the center of the field. Discussion As long as the baclofen pump is >1 cm away from the ERC, the pump will not stall, regardless of the length of time the ERC generates a magnetic field.

Magnetically controlled growing rod in 13 patients with early-onset scoliosis and spinal improvement

ObjectiveThe aim of this study was to examine the use of magnetically controlled growing rods as a method of providing spinal improvement while preventing thoracic insufficiency in patients with early-onset scoliosis (EOS). MethodsOf a total of 13 patients, 4 patients underwent a dual magnetic rod implantation, while 9 patients had a single magnetic rod procedure. The study group comprised 12 (93%) female and 1 (7%) male patients. Six patients (46%) had an idiopathic form of scoliosis, in 4 (30%) it was congenital, and in 3 (23%) it was neuromuscular scoliosis. The patients' Cobb angles, thoracic kyphosis, T1-T12 and T1-S1 distance prior to and following the treatment were compared. ResultsThe mean Cobb angle before surgery was 53.780, whereas it decreased to 39.290 postoperatively (p < 0.001). The mean thoracic kyphosis angle was 400 before and 29.790 after surgery (p < 0.001). The mean T1-S1 distance was 32.14 cm before and 36.36 cm after surgery (p < 0.001). The mean T1-T12 distance was 18.69 cm before and 20.64 cm after surgery (p < 0.001). ConclusionThe use of magnetic rods is an effective method of EOS treatment. It allows for spinal growth while managing the progression of the scoliosis. Level of evidenceLevel IV, therapeutic study.

Using magnets for particle extraction from powder flow

A model is explored for the extraction of ferromagnetic metallic particles using a magnetic filtration system. These metallic particles, which are transported by a powder flow may be fragments resulting from the standard wear and tear on industrial machinery. A project of this nature was brought to the 2015 Mathematics and Statistics in Industry NZ Study Group. Possible configurations of the magnetic filtration systems are considered with the target of better particle capture. The dependence of the model on the metallic particle's release zone and velocity is investigated. Monte-Carlo simulations are conducted for cases using perpendicular as well as parallel magnetic rods. The results confirm the efficacy of parallel offset rods and emphasise the importance of dense rod placement. The approach could be used to explore further alternative rod arrangements in advance of experimental implementation. References S.M. Blinder (2011) Magnetic Field of a Cylindrical Bar Magnet Wolfram Demonstrations Project. http://demonstrations.wolfram.com/MagneticFieldOfACylindricalBarMagnet/ J.C. Butcher (2008) Numerical Methods for Ordinary Differential Equations , John Wiley and Sons Ltd., England. H. Cooper, J. Denier, A. Ali, V. Chopovda, A. Gulley (2017) Modelling the effectiveness of magnets in particle extraction , ANZIAM Journal (2017), 57: M332–M352. doi:10.21914/anziamj.v57i0.12037 A. Einstein (1906) Eine neue Bestimmung der Molekuldimensionen , Ann. Phys., 324: 289–306. A. Einstein, R. Furth (1893-1956) Investigations on the theory of the Brownian movement , Dover. isbn=978-0-486-60304-9 Y. Nakai, F. Mishima, Y. Akiyama, S. Nishijima (2010) Development of Magnetic Separation System for Powder Separation , IEEE Transactions on applied superconductivity, 20:3, 941-944. doi:10.1109/TASC.2010.2043086 S. Noguchi, S. Kim (2011) Development of a numerical simulation method for the magnetic separation of magnetic particles , IEEE Transactions on magnetics, 47:5, 898-901. doi:10.1109/CEFC.2010.5481745 A.W. Strandling (1993) The physics of open-gradient dry magnetic separation , International Journal of Mineral Processing, 39, 1-18. doi:10.1016/0301-7516(93)90048-F J. Svoboda, T. Fujita (2003) Recent developments in magnetic methods of material separation , Minerals Engineering, 16, 785-792. doi:10.1016/S0892-6875(03)00212-7

Magnetic drilling enhances intra-nasal transport of particles into rodent brain

Getting drugs deep into the brain to treat cancers, neurological disease, and behavioral disorders is challenging. In this work, we tried to improve the efficiency of intra-nasal transport into the brain via the cribriform plate using magnetic particles. We and others have used magnetic particles for delivering heat, drugs, and genes. We performed experiments with mouse cadavers that received 250-nm-wide intra-nasal magnetic rods intra-nasally under different combinations of magnetic fields. We found that the application of helical dynamic gradients to the particles (i.e., both rotational and linear) improved transport from the nose into the brain, as compared to linear magnetic gradients alone. On histological examination, no tracks were observed to suggest significant damage to the brain during the transport process. We are currently building a system for testing with live animals, with eventual proposed application to humans.

Novel production method of tracer particles for residence time measurements in gas-solid processes

In order to measure the residence time distribution (RTD) in continuous gas-solid processes tracer particles are used. In this contribution, a novel production concept for magnetizable particles has been developed and optimized. The process includes coating of a fraction of the investigated bed material with a magnetizable paint in a laboratory spouted bed. The coated particles fulfill the requirements of tracer material, are resistant, harmless to health and reusable. After passing a continuously operated process, the tracer material can be separated by a magnetic rod from the sample, which allows the fast and easy calculation of the exit age distribution as demonstrated in this contribution with a horizontal fluidized bed.

Correction: Self-assembly and clustering of magnetic peapod-like rods with tunable directional interaction.

[This corrects the article DOI: 10.1371/journal.pone.0195552.].

Analysis of GRACE range-rate residuals with focus on KBR instrument system noise

We investigate the post-fit range-rate residuals after the gravity field parameter estimation from the inter-satellite ranging data of the gravity recovery and climate experiment (grace) satellite mission. Of particular interest is the high-frequency spectrum (f> 20 mhz) which is dominated by the microwave ranging system noise. Such analysis is carried out to understand the yet unsolved discrepancy between the predicted baseline errors and the observed ones. The analysis consists of two parts. First, we present the effects in the signal-to-noise ratio (snrs) of the k-band ranging system. The snrs are also affected by the moon intrusions into the star cameras’ field of view and magnetic torquer rod currents in addition to the effects presented by Harvey et al. (2016). Second, we analyze the range-rate residuals to study the effects of the kbr system noise. The range-rate residuals are dominated by the non-stationary errors in the high-frequency observations. These high-frequency errors in the range-rate residuals are found to be dependent on the temperature and effects of sun intrusion into the star cameras’ field of view reflected in the snrs of the k-band phase observations.

Maximal force generated by magnetically controlled growing rods at different magnetic controlled growing rod length decreases with rod lengthening

The introduction of magnetically controlled growing rods (MCGR) has been met with great enthusiasm by surgeons managing early onset scoliosis. The new devices offer the potential to decrease the cost and morbidity associated with repeated lengthening surgeries for the patient compared to traditional growing rods (TGR). One of the potential negative consequences of the growing rod treatment is the law of diminishing returns, where the spine length gained tends to decrease with each subsequent lengthening …

Designing High-Accuracy Permanent Magnets for Low-Power Magnetic Resonance Imaging

We present a highly scalable and versatile family of dipole magnet designs suitable for high-resolution magnetic resonance imaging (MRI), constructed entirely from cylindrical permanent magnet rods of two distinct radii. The multiplicity, $N$ , of the main set of rods (which dominate the generated field) can vary from 10 to 26. For each such $N$ , we present several designs that produce magnetic fields uniform to better than 100 parts per million (ppm) over spherical regions of radius half that of the bore. This design family includes peak fields ranging from 0.15 to 0.50 T, adjustable by changing $N$ , with the best accuracy obtained for $N=14$ with a peak field of 0.32 T. With optional correction rods that start out in a zero field configuration, these designs can be tuned to compensate for manufacturing errors simply by adjusting the rotations of these rods. Most of the 100 ppm accuracy radius can thereby be recovered, even in realistic imperfect configurations. We specifically present dimensions for full-body MRI with a standard bore (clearance) diameter of 70 cm, but this family of designs can be scaled uniformly to produce high-uniformity magnetic fields for applications at any length scale.

Ferrofluid of magnetic clay and menthol based deep eutectic solvent: Application in directly suspended droplet microextraction for enrichment of some emerging contaminant explosives in water and soil samples

In this work, for the first time, ferrofluid of magnetic montmorillonite nanoclay and deep eutectic solvent was prepared and coupled with directly suspended droplet microextraction. Incorporation of ferrofluid in a miniaturized sample preparation technique resulted in achieving high extraction efficiency while developing a green analytical method. The prepared ferrofluid has strong sorbing properties and hydrophobic characteristics. In this method, a micro-droplet of ferrofluid was suspended into the vortex of a stirring aqueous solution and after completing the extraction process, was easily separated from the solution by a magnetic rod without any operational problems. The predominant experimental variables affecting the extraction efficiency of explosives were evaluated. Under optimal conditions, the limits of detection were in the range 0.22–0.91 μg L−1. The enrichment factors were between 23 and 93 and the relative standard deviations were <10%. The relative recoveries were ranged from 88 to 104%. This method was successfully applied for the extraction and preconcentration of explosives in water and soil samples, followed their determination by high performance liquid chromatography with ultraviolet detection (HPLC-UV).

Self-assembly and clustering of magnetic peapod-like rods with tunable directional interaction.

Based on extensive Langevin Dynamics simulations we investigate the structural properties of a two-dimensional ensemble of magnetic rods with a peapod-like morphology, i.e, rods consisting of aligned single dipolar beads. Self-assembled configurations are studied for different directions of the dipole with respect to the rod axis. We found that with increasing misalignment of the dipole from the rod axis, the smaller the packing fraction at which the percolation transition is found. For the same density, the system exhibits different aggregation states for different misalignment. We also study the stability of the percolated structures with respect to temperature, which is found to be affected by the microstructure of the assembly of rods.

Novel capsule phase microextraction in combination with liquid chromatography-tandem mass spectrometry for determining personal care products in environmental water.

A novel sample preparation technique named capsule phase microextraction (CPME) is presented here. The technique utilizes a miniaturized microextraction capsule (MEC) as the extraction medium. The MEC consists of two conjoined porous tubular polypropylene membranes, one of which encapsulates the sorbent through sol-gel technology, while the other encapsulates a magnetic metal rod. As such, MEC integrates both the extraction and stirring mechanisms into a single device. The aim of this article is to demonstrate the application potential of CPME as sample preparation technique for the extraction of a group of personal care products (PCPs) from water matrices. Among the different sol-gel sorbent materials (UCON®, poly(caprolactone-dimethylsiloxane-caprolactone) (PCAP-DMS-CAP) and Carbowax 20M (CW-20M)) evaluated, CW-20M MEC demonstrated the best extraction performance for the selected PCPs. The extraction conditions for sol-gel CW-20M MEC were optimized, including sample pH, stirring speed, addition of salt, extraction time, sample volume, liquid desorption solvent, and time. Under the optimal conditions, sol-gel CW-20M MEC provided recoveries, ranging between 47 and 90% for all analytes, except for ethylparaben, which showed a recovery of 26%. The method based on CPME with sol-gel CW-20M followed by liquid chromatography-tandem mass spectrometry was developed and validated for the extraction of PCPs from river water and effluent wastewater samples. When analyzing different environmental samples, some analytes such as 2,4-dihydroxybenzophenone, 2,2-dihydroxy-4-4 methoxybenzophenone and 3-benzophenone were found at low ngL-1.

Behavioural responses of draughtboard sharks (Cephaloscyllium laticeps) to rare earth magnets: Implications for shark bycatch management within the Tasmanian southern rock lobster fishery

Catches of draughtboard shark (Cephaloscyllium laticeps) in the Tasmanian Southern Rock Lobster Fishery are considered an economic and potentially ecological issue. Consequently, there is interest in developing strategies to mitigate and minimise shark bycatch within this fishery. This field study examined the behavioural responses of draughtboard sharks to neodymium-iron-boron (Nd2Fe14B) rare earth magnetic rods attached to baited video apparatus. Two magnetic treatments and one control were used in 12 × 1.5 h observational trials conducted in inshore waters of Tasmania, Australia. Results demonstrate that draughtboard sharks: (1) showed substantial individual variation in behaviours both between and within treatments, with no patterns of individual responses observed over time to both magnetic treatments or the control, (2) showed significant differences in initial interactions between the magnetic treatments and the control, and (3) attempted to take bait at the control significantly more often than at the 2-magnet treatment. These findings demonstrate the individualistic and highly variable response behaviours of draughtboard sharks to rare earth magnets. Understanding such behaviours may facilitate the development of effective deterrent strategies in this fishery and improve management of shark-fishery interactions globally.

Transformational magnetic play set as mind opener game in a Problem Based Learning workshop

BACKGROUND AND AIM Critical thinking and application are imperative skills for medical students as they learn to look for clinical features, interpret investigation, diagnose and treat patients. Many educational strategies exist to foster this process, one of which is Problem based learning (PBL). Though the concept of PBL looks lucid and uncomplicated, it requires understanding of the principles by faculties and students to make it more student oriented. We used a ‘Magnetic Building Set’ as a mind opener to orient the teaching faculty at RAK Medical and Health Sciences University (RAKMHSU) to the core concepts of PBL. The main aim of the workshop was to familiarize the faculty on various aspects of PBL especially the importance of identification of learning objectives; designing a problem on predesigned objectives and the relation of PBL to inquiry based learning. The study also depicts how a simple game can make the participants correlate with the principles behind PBL. METHODS A total of 17 new faculty members, some of them having previous exposure of teaching in a PBL curricula were included in the Medical Education orientation workshop on PBL. The faculty members were divided into groups and each group was given a magnetic building set, which consisted of metallic spheres and magnetic rods. Initially there were asked to make design of their choice using all the materials and later a second task was given asking them to make a specific structure. The game is then correlated to the key principles of PBL using a pre and post- game questionnaire. RESULTS After the game, the knowledge of the faculty regarding the concepts and efficient use of PBL increased dramatically. The post-game questionnaire showed all the faculty understood well about the concepts of PBL. CONCLUSION Various instructional strategies are employed in adult learning. Game based learning is one amongst them and the current study highlights how a simple game can be used as an innovative and effective approach to introduce the concepts of PBL.