The impact of turbulent flow on the solidification of metal alloys driven by a rotating magnetic field

This paper presents an experimental study which in a first stage is focused on obtaining quantitative information about the isothermal flow field exposed to various magnetic field configurations. Melt stirring has been realized by utilizing a rotating magnetic field. In a second step directional solidification of AlSi7 alloys from a water-cooled copper chill was carried out to verifythe effect of a certain flow field on the solidification process and on the resulting mechanical properties. The solidified structure was reviewed in comparison to an unaffected solidified ingot. Measurements of the phase distribution, the grain size, the hardness and the tensile strength were realized. Our results demonstrate the potential of magnetic fields to control the grain size, the formation of segregation freckles and the mechanical properties. In particular, time–modulated rotating fields show their capability to homogenize both the grain size distribution and the corresponding mechanical properties.

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Biochemical and cellular properties of Gluconacetobacter xylinus cultures exposed to different modes of rotating magnetic field

Polish Journal of Chemical Technology ◽

10.1515/pjct-2017-0036 ◽

2017 ◽

Vol 19 (2) ◽

pp. 107-114 ◽

Cited By ~ 3

Author(s):

Karol Fijałkowski ◽

Radosław Drozd ◽

Anna Żywicka ◽

Adam F. Junka ◽

Marian Kordas ◽

...

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Positive Impact ◽

Biochemical Properties ◽

Rotating Magnetic Field ◽

Cellulose Synthesis ◽

Gluconacetobacter Xylinus ◽

Biochemical Processes ◽

Different Types ◽

The Impact

Abstract The aim of the present study was to evaluate the impact of a rotating magnetic field (RMF) on cellular and biochemical properties of Gluconacetobacter xylinus during the process of cellulose synthesis by these bacteria. The application of the RMF during bacterial cellulose (BC) production intensified the biochemical processes in G. xylinus as compared to the RMF-unexposed cultures. Moreover, the RMF had a positive impact on the growth of cellulose-producing bacteria. Furthermore, the application of RMF did not increase the number of mutants unable to produce cellulose. In terms of BC production efficacy, the most favorable properties were found in the setting where RMF generator was switched off for the first 72 h of cultivation and switched on for the further 72 h. The results obtained can be used in subsequent studies concerning the optimization of BC production using different types of magnetic fields including RMF, especially.

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Time Dependent Influence of Rotating Magnetic Field on Bacterial Cellulose

International Journal of Polymer Science ◽

10.1155/2016/7536397 ◽

2016 ◽

Vol 2016 ◽

pp. 1-13 ◽

Cited By ~ 3

Author(s):

Karol Fijałkowski ◽

Rafał Rakoczy ◽

Anna Żywicka ◽

Radosław Drozd ◽

Beata Zielińska ◽

...

Keyword(s):

Magnetic Field ◽

Bacterial Cellulose ◽

Water Retention ◽

Rotating Magnetic Field ◽

Water Retention Capacity ◽

Water Molecules ◽

Retention Capacity ◽

Exposure System ◽

The Impact ◽

Water Holding

The aim of the study was to assess the influence of rotating magnetic field (RMF) on the morphology, physicochemical properties, and the water holding capacity of bacterial cellulose (BC) synthetized by Gluconacetobacter xylinus. The cultures of G. xylinus were exposed to RMF of frequency that equals 50 Hz and magnetic induction 34 mT for 3, 5, and 7 days during cultivation at 28°C in the customized RMF exposure system. It was revealed that BC exposed for 3 days to RMF exhibited the highest water retention capacity as compared to the samples exposed for 5 and 7 days. The observation was confirmed for both the control and RMF exposed BC. It was proved that the BC exposed samples showed up to 26% higher water retention capacity as compared to the control samples. These samples also required the highest temperature to release the water molecules. Such findings agreed with the observation via SEM examination which revealed that the structure of BC synthesized for 7 days was more compacted than the sample exposed to RMF for 3 days. Furthermore, the analysis of 2D correlation of Fourier transform infrared spectra demonstrated the impact of RMF exposure on the dynamics of BC microfibers crystallinity formation.

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Transitional and weakly turbulent flow in a rotating magnetic field

Physics of Fluids ◽

10.1063/1.2221347 ◽

2006 ◽

Vol 18 (7) ◽

pp. 074105 ◽

Cited By ~ 31

Author(s):

J. Stiller ◽

K. Fraňa ◽

A. Cramer

Keyword(s):

Magnetic Field ◽

Turbulent Flow ◽

Rotating Magnetic Field

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Removal of fluoride ions using a polypyrrole magnetic nanocomposite influenced by a rotating magnetic field

RSC Advances ◽

10.1039/c9ra07379e ◽

2020 ◽

Vol 10 (1) ◽

pp. 595-609 ◽

Cited By ~ 4

Author(s):

Uyiosa Osagie Aigbe ◽

Robert Birundu Onyancha ◽

Kingsley Eghonghon Ukhurebor ◽

Kingsley Onyebuchi Obodo

Keyword(s):

Magnetic Field ◽

Rotating Magnetic Field ◽

Magnetic Nanocomposite ◽

Polymerization Process ◽

Fluoride Ions ◽

The Impact

The impact of a varying rotating magnetic field in stimulating adsorption of fluoride ions onto a polypyrrole magnetic nanocomposite synthesized via in situ a polymerization process was evaluated.

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Rotating Magnetic Field Increases β-Lactam Antibiotic Susceptibility of Methicillin-Resistant Staphylococcus aureus Strains

International Journal of Molecular Sciences ◽

10.3390/ijms222212397 ◽

2021 ◽

Vol 22 (22) ◽

pp. 12397

Author(s):

Marta Woroszyło ◽

Daria Ciecholewska-Juśko ◽

Adam Junka ◽

Radosław Drozd ◽

Marcin Wardach ◽

...

Keyword(s):

Magnetic Field ◽

Staphylococcus Aureus ◽

Cell Walls ◽

Intact Cell ◽

Rotating Magnetic Field ◽

Developmental Potential ◽

Methicillin Resistant ◽

Morphological Alterations ◽

Minimal Inhibitory Concentrations ◽

The Impact

Methicillin-resistant strains of Staphylococcus aureus (MRSA) have developed resistance to most β-lactam antibiotics and have become a global health issue. In this work, we analyzed the impact of a rotating magnetic field (RMF) of well-defined and strictly controlled characteristics coupled with β-lactam antibiotics against a total of 28 methicillin-resistant and sensitive S. aureus strains. The results indicate that the application of RMF combined with β-lactam antibiotics correlated with favorable changes in growth inhibition zones or in minimal inhibitory concentrations of the antibiotics compared to controls unexposed to RMF. Fluorescence microscopy indicated a drop in the relative number of cells with intact cell walls after exposure to RMF. These findings were additionally supported by the use of SEM and TEM microscopy, which revealed morphological alterations of RMF-exposed cells manifested by change of shape, drop in cell wall density and cytoplasm condensation. The obtained results indicate that the originally limited impact of β-lactam antibiotics in MRSA is boosted by the disturbances caused by RMF in the bacterial cell walls. Taking into account the high clinical need for new therapeutic options, effective against MRSA, the data presented in this study have high developmental potential and could serve as a basis for new treatment options for MRSA infections.

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