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2022 ◽  
Vol 105 (2) ◽  
Author(s):  
Silvia Galli ◽  
Levon Pogosian ◽  
Karsten Jedamzik ◽  
Lennart Balkenhol

2021 ◽  
Author(s):  
◽  
Shaun Swan

<p>The fabrication of piezoelectric ceramics (Piezoceramics) currently relies on a costly dice and fill process to create an array of aligned pillars. These pillars act as waveguides, improving the performance of the piezoceramic wafers over the bulk piezoceramic alone. It is theorised the creation of aligned pores in the piezoceramic may exhibit the same waveguiding effect, removing the need for the dice and fill process.  A technique for creating these pores is in development at Callaghan Innovation, New Zealand, where nickel coated carbon fibers are added to the ceramic slurry, aligned with a magnetic field, and attracted to the bottom of a mold. The number of fibers and degree of alignment dictate the waveguiding effectiveness and hence the performance of the piezoceramic. Additionally the time taken for fibers to form an array in the bottom of the mold dictate the piezoceramics fabrication time. Thus it is crucial to be able to measure the alignment and magnetically assisted sedimentation of these fibers in-situ. However the ceramic slurry is opaque, hence the optical methods traditionally can not be implemented.  This thesis describes the development and implementation of an electrical technique using the anisotropic conductance of fibers, for measuring fiber dynamics during the fabrication of piezoceramics. The results of this electrical technique are compared to both optical monitoring results in a transparent solution, and models for the motion of rigid cylinders in a fluid suspension.  The change in conductance corresponding to fiber rotation was found to have a time constant corresponding to fiber rotation which is a scalar multiple of that of transmission microscopy and the mathematical modeling. This is a product of the geometry of the electrode configurations used to measure conductance. Furthermore, for fiber rotation, the fiber concentration in the solution changes the effective fluid viscosity due to hydrodynamic turbulence created by the rotating fibers.  The conductance change corresponding to the magnetically assisted fiber settling is in good accordance with both the optical observations and mathematical modeling for 50 mPas solutions, however for 30 mPas solutions the modeling underestimates the settling time by 20%. The maximum fiber concentration to create a single layer of aligned fibers in the bottom of the mold was found to be 12 fibers=mm³. Exceeding this limit results in a secondary and tertiary layer of fibers forming directly below the fiber suspension injection location.</p>


2021 ◽  
Author(s):  
◽  
Shaun Swan

<p>The fabrication of piezoelectric ceramics (Piezoceramics) currently relies on a costly dice and fill process to create an array of aligned pillars. These pillars act as waveguides, improving the performance of the piezoceramic wafers over the bulk piezoceramic alone. It is theorised the creation of aligned pores in the piezoceramic may exhibit the same waveguiding effect, removing the need for the dice and fill process.  A technique for creating these pores is in development at Callaghan Innovation, New Zealand, where nickel coated carbon fibers are added to the ceramic slurry, aligned with a magnetic field, and attracted to the bottom of a mold. The number of fibers and degree of alignment dictate the waveguiding effectiveness and hence the performance of the piezoceramic. Additionally the time taken for fibers to form an array in the bottom of the mold dictate the piezoceramics fabrication time. Thus it is crucial to be able to measure the alignment and magnetically assisted sedimentation of these fibers in-situ. However the ceramic slurry is opaque, hence the optical methods traditionally can not be implemented.  This thesis describes the development and implementation of an electrical technique using the anisotropic conductance of fibers, for measuring fiber dynamics during the fabrication of piezoceramics. The results of this electrical technique are compared to both optical monitoring results in a transparent solution, and models for the motion of rigid cylinders in a fluid suspension.  The change in conductance corresponding to fiber rotation was found to have a time constant corresponding to fiber rotation which is a scalar multiple of that of transmission microscopy and the mathematical modeling. This is a product of the geometry of the electrode configurations used to measure conductance. Furthermore, for fiber rotation, the fiber concentration in the solution changes the effective fluid viscosity due to hydrodynamic turbulence created by the rotating fibers.  The conductance change corresponding to the magnetically assisted fiber settling is in good accordance with both the optical observations and mathematical modeling for 50 mPas solutions, however for 30 mPas solutions the modeling underestimates the settling time by 20%. The maximum fiber concentration to create a single layer of aligned fibers in the bottom of the mold was found to be 12 fibers=mm³. Exceeding this limit results in a secondary and tertiary layer of fibers forming directly below the fiber suspension injection location.</p>


Author(s):  
Palwinder Singh ◽  
Lakhvir Singh

Abstract Magnetically assisted abrasive finishing (MAAF) presents an attractive concept of surface and edge finishing by fine magnetic abrasive particles (MAPs). This study aims to contribute an experimental evaluation of the effect of process parameters viz. magnetic field density (MFD), circumferential speed of workpiece, and abrasive grit size on the surface finishing properties in MAAF when experiments were performed for finishing pipes of ASTM B16 brass material with the sintered MAPs. The developed model is based on the obtained experimental data accompanied by “Box- Behnken design (BBD) of response surface methodology (RSM)” analysis. Apart from deciding significant parameters, this analysis also presents the modeling of finishing properties and optimizes the desired performance parameters. Analysis of variance (ANOVA) includes data of standard deviation, coefficient of determination (R2), adjusted, and predicted (R2). MFD and speed show a significant effect on both the responses viz. “surface roughness improvement rate (SRIR) and material removal rate (MRR)”. Analysis has shown that abrasive grit size is the most dominant parameter towards SRIR followed by MFD. The maximum SRIR of 88.12% (minimum Ra 50 nm) and 4.28 mg/min is achieved through multi-objective optimization with 0.8 T MFD, 500 rpm speed, and 300 µm grit size. The mathematical models of SRIR and MRR were also developed using RSM, focusing on varying MFD, speed, and grit size which can be used to predict the desired surface finishing properties. The model generated for SRIR, and MRR has an error of 0.204 % and 2.506 % respectively. Further SEM images were taken to understand the surface appearance of the finished surface.


2021 ◽  
Vol 11 (6) ◽  
pp. 176-187
Author(s):  
Mahammed Athar Alli Saikh ◽  
Prithwiraj Mohapatra

The manuscript aims to provide glimpse on updated information relating thermo-mechanical dry coating processes (TMDCP) suiting in modifying surface attributes of fine and ultra-fine particle (FiUlFiP). FiUlFiPs are the integral component of pharmaceutical processes. They exhibit complex and queer properties, are conferred mostly from their surface attributes colligated with their higher surface area. Particle engineering technocrats extensively working for modifying surface & surface attributes of FiUlFiPs. These efforts are to find their worthy applications & new functionalities. Among available diverse particle engineering technologies/ process, TMDCP, a dry coating process (DCP), advocated being worthy and efficient. The TMDCP finds multidisciplinary applications, mostly in drug development & drug delivery. Said DCP involves fixing and/or attaching coating material (CoM) as particles herein synonym guest particle (GP) onto core/substrate particle (CSP) herein synonym host particle (HP). Attaching/ fixing the GPs onto HPs, in TMDCP, involve their mechanical and/or thermal interactions. Scientific literatures are evidencing diverse techniques and/or process, basing on discussed interactions. Amongst them novel techniques/ processes are Hybridization, Magnetically assisted impaction coating process (MAICP), Mechanofusion, Theta-composer, and high shear compaction. In this area diverse devices/ equipments are prevailing in market. Important are Hybridizer, Magnetically assisted impaction coater (MAIC), Theta-composer, Mechanofusion, Quadro Comil®, Cyclomix®, and many others. Attempt of this article is to discuss and present their method of working, working principle, applicability, limitations, and benefits. Contained information might be beneficial for professionals of pharmaceutical and allied field. Keywords: dry coating, equipment, particles, processes, thermo-mechanical.


Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3950
Author(s):  
Anna Żywicka ◽  
Daria Ciecholewska-Juśko ◽  
Radosław Drozd ◽  
Rafał Rakoczy ◽  
Maciej Konopacki ◽  
...  

The aim of this study was to demonstrate the applicability of a novel magnetically assisted external-loop airlift bioreactor (EL-ALB), equipped with rotating magnetic field (RMF) generators for the preparation of Komagataeibacter xylinus inoculum during three-cycle repeated fed-batch cultures, further used for bacterial cellulose (BC) production. The fermentation carried out in the RMF-assisted EL-ALB allowed to obtain an inoculum of more than 200 × higher cellular density compared to classical methods of inoculum preparation. The inoculum obtained in the RMF-assisted EL-ALB was characterized by a high and stable metabolic activity during repeated batch fermentation process. The application of the RMF-assisted EL-ALB for K. xylinus inoculum production did not induce the formation of cellulose-deficient mutants. It was also confirmed that the ability of K. xylinus to produce BC was at the same level (7.26 g/L of dry mass), regardless of inoculum age. Additionally, the BC obtained from the inoculum produced in the RMF-assisted EL-ALB was characterized by reproducible water-related properties, mechanical strength, nano-fibrillar structure and total crystallinity index. The lack of any negative impact of inoculum preparation method using RMF-assisted EL-ALB on BC properties is of paramount value for its future applications, including use as a biomaterial in tissue engineering, wound healing, and drug delivery, where especially BC liquid capacity, nanostructure, crystallinity, and mechanical properties play essential roles.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1650
Author(s):  
Marco Bassetto ◽  
Daniel Ajoy ◽  
Florent Poulhes ◽  
Cathy Obringer ◽  
Aurelie Walter ◽  
...  

Barded-Biedl syndrome (BBS) is a rare genetic disorder with an unmet medical need for retinal degeneration. Small-molecule drugs were previously identified to slow down the apoptosis of photoreceptors in BBS mouse models. Clinical translation was not practical due to the necessity of repetitive invasive intravitreal injections for pediatric populations. Non-invasive methods of retinal drug targeting are a prerequisite for acceptable adaptation to the targeted pediatric patient population. Here, we present the development and functional testing of a non-invasive, topical, magnetically assisted delivery system, harnessing the ability of magnetic nanoparticles (MNPs) to cargo two drugs (guanabenz and valproic acid) with anti-unfolded protein response (UPR) properties towards the retina. Using magnetic resonance imaging (MRI), we showed the MNPs’ presence in the retina of Bbs wild-type mice, and their photoreceptor localization was validated using transmission electron microscopy (TEM). Subsequent electroretinogram recordings (ERGs) demonstrated that we achieved beneficial biological effects with the magnetically assisted treatment translating the maintained light detection in Bbs−/− mice (KO). To our knowledge, this is the first demonstration of efficient magnetic drug targeting in the photoreceptors in vivo after topical administration. This non-invasive, needle-free technology expands the application of SMDs for the treatment of a vast spectrum of retinal degenerations and other ocular diseases.


PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0256519
Author(s):  
Dong Jun Oh ◽  
Ji Hyung Nam ◽  
Junseok Park ◽  
Youngbae Hwang ◽  
Yun Jeong Lim

Magnetically assisted capsule endoscopy (MACE) is a noninvasive procedure and can overcome passive capsule movement that limits gastric examination. MACE has been studied in many trials as an alternative to upper endoscopy. However, to increase diagnostic accuracy of various gastric lesions, MACE should be able to provide stereoscopic, clear images and to measure the size of a lesion. So, we conducted the animal experiment using a novel three-dimensional (3D) MACE and a new hand-held magnetic controller for gastric examination. The purpose of this study is to assess the performance and safety of 3D MACE and hand-held magnetic controller through the animal experiment. Subsequently, via the dedicated viewer, we evaluate whether 3D reconstruction images and clear images can be obtained and accurate lesion size can be measured. During real-time gastric examination, the maneuverability and visualization of 3D MACE were adequate. A polypoid mass lesion was incidentally observed at the lesser curvature side of the prepyloric antrum. The mass lesion was estimated to be 10.9 x 11.5 mm in the dedicated viewer, nearly the same size and shape as confirmed by upper endoscopy and postmortem examination. Also, 3D and clear images of the lesion were successfully reconstructed. This animal experiment demonstrates the accuracy and safety of 3D MACE. Further clinical studies are warranted to confirm the feasibility of 3D MACE for human gastric examination.


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