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In view of the temperature rise, noise and vibration between the rotor and the support bearings under the high-speed rotating state of the PMSMS, the bearingless technology is proposed for avoiding the contact between the rotor and the support bearings and achieving stable compensation of the motorized spindles under high-speed running state. Based on the modeling method of ordinary bearingless motors, mathematical models of the BPMSS and simulation experiments are carried out. At the same time, the variable structure PID is used in the displacement controller to optimize the displacement control of the rotor. The results prove the feasibility of bearingless technology on permanent magnet synchronous motorized spindles. The magnetic levitation system largely avoids the contact between the rotor and the support bearings, which can solve the noise and vibration problems of the rotor when running at high speeds. Variable structure PID has a stronger control effect on rotor displacement control than ordinary PID control strategy. [ABSTRACT FROM AUTHOR]

Ultralong hydroxyapatite nanofibers (UHANFs) have received much more attention and been widely used in recent years for their inherent size‐dependent properties. However, the intrinsic agglomeration and brittleness of this material limited its application in some aspects. To overcome the agglomeration of UHANFs and instability of the molding slurry, a model was established inspired by the zeta potential and DLVO theory. The model was of utmost importance to provide a theoretical basis to link potential changes and material properties, and the most desirable state was achieved when the solid content was 2 wt%. In addition, the composites of UHANFs and organics could resolve part of the brittleness problem. Herein, we proposed a simple and environment‐friendly approach to manufacturing the biomimetic UHANFs/(chitosan‐gelatin) composite films. The synthesized products with different proportions of UHANFs were characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), water vapor transmission rate (WVTR), swelling, and mechanical studies. The results showed that the ratio of UHANFs to organic matter had a profound influence on the combination properties of the composites. When the UHANFs content reached 70% in the films, the tensile strength and Young's modulus were 66.7% and 70.5% higher than that of samples containing 80% UHANFs. The respectable biological and mechanical properties of these films made them have the potential application in bone defect repair. [ABSTRACT FROM AUTHOR]

Kinetics of electrophoretic deposition (EPD) has been thoroughly investigated using equivalent circuit modeling in this paper. The aim of this work is the better understanding of the EPD mechanism. In this case, mass deposition in EPD was modeled as charging of the reservoir in an RC circuit. Accordingly, the weight–time (w – t) curves of EPD were regarded equivalent to the V – t curves of a reservoir. It was found out that the rate of deposition depends not only on the specific resistivity but also on the permittivity of the suspension. Furthermore, the mechanism of EPD was studied using large- and small-signal analyses conducted by the Simulink modeling toolbox of MATLAB software. In this case, the frequency of sinusoidal waves was equivalent to the probability of collision of particles. Results show that there is an alternative sinusoidal-like noise on the main signal of w – t curves. It predicts that charged particles move toward the opposite electrode during the EPD process and accumulate next to the electrode for losing their ionic power. Ultimately, the accumulated particles (including several particles not owing ionic power) depose on the electrode at once. The time which is needed for particles to decrease their ionic power is a delay (relaxation) time of the deposition process. [ABSTRACT FROM AUTHOR]

The electrophoretic deposition (EPD) of coatings and bulk compacts in a wide range of thicknesses (from 23 to 1800 μm) from stable suspensions of a magnesium-doped aluminum oxide nanopowder with subsequent sintering of samples into dense ceramics was studied. The initial nanopowder was obtained by the method of electric explosion of an Al-Mg alloy wire with a Mg content of 1.3 wt. %. The study of the dispersion composition, kinetics of deaggregation under the ultrasonic treatment and zeta potential in the nanopowder-based suspensions was carried out. It was shown that a nearly linear increase in the deposited mass and thickness of EPD deposits occurred at a constant voltage of 20 V and an average deposition current of approximately 40 μA when the deposition time was varied from 1 to 180 min. Drying of the coatings with a thickness of less than 35 μm led to the formation of a net of small cracks, while drying of the bulk compacts with a thickness of more than 1 mm occurred without cracking. The ceramic bulk sample with a thickness of 1.2 mm and the density of 98.7% TD was successfully obtained by sintering at 1650 °C for 4 h. It was characterized by a dense grain structure with an average grain size of 5 μm and the presence of a small number of closed pores less than 1 μm in size. Sintering of ceramics was revealed to be accompanied by the formation of a MgAl2O4 crystalline spinel phase, localized mainly at grain boundaries.

Graphene-based filaments or yarns offering outstanding electrically-conductive and lightweight advantages are competitive candidates for flexible wires. The challenge is that low-oxidizing graphene tend to aggregate due to strong interaction among sheets, and it is difficult to assemble graphene into filaments. At present, even though diverse strategies are introduced to ameliorate graphene dispersibility and fabricability, their technological processes are often intricate and the corresponding fibers are severely flimsy. Herein, aramid nanofibers (ANFs) with excellent nanoscale dispersity and mechanical property are chosen as an auxiliary to support graphene nanoplates (GNPs) by non-covalent interactions and electrostatic repulsive-force in solvent. Moreover, a one-step process via simple wet-spinning is presented to fabricate GNPs/ANFs wires directly. The resultant GNPs/ANFs wire with a weight ratio of 80/20 demonstrates a high conductivity of 4236 S/m and tensile strength of 227.5 MPa with 10.2% elongation simultaneously. Even more, benefiting from the introduction of ANFs framework, the hybrid fibers not only have superior durability but also withstand burning and high temperature exceeding 400 °C. This work provides a strategy for the assembly of a novel flexible wire, which is facile for mass production and has a potential value for wearable devices. ANFs is adhered to GNPs surface by the non-covalent connection and π-π interaction. Deprotonated ANFs carrying the negative charge produce a strong repulsive-force for adjacent graphene sheets, thus resulting in the homogeneous dispersion of GNPs in the solvent. A continuous GNPs/ANFs composite filament with tough mechanical property, great electrical conductivity and excellent thermostability are fabricated by wet-spinning technique. [Display omitted] • Aramid nanofibers were implemented to ameliorate the dispersibility, processibility and performance of graphene nanoplates. • High tensile strength, elongation and axial electrical conductivity were simultaneously achieved in the filament. • The flame retardancy ensures security when breaking out of fire. • The flexible wires for wearable devices have a long service life. [ABSTRACT FROM AUTHOR]

This paper presents a study of nonaqueous suspensions based on ZrO2–8 mol % Y2O3 (8YSZ) powders and describes the use of the powders for producing thin-film coatings on a La2NiO4 (LNO) substrate by electrophoretic deposition (EPD). Stable suspensions for EPD have been prepared using 8YSZ powders differing in morphology and particle size: nanopowder (YSZ_L) produced by a laser evaporation–condensation process and commercially available powder (YSZ_T) (Tosoh, Japan). Ultrasonic processing has been found to have different effects on the particle size composition of the YSZ_L and YSZ_T suspensions. The two types of suspension have been shown to differ significantly in the kinetics of the deposition current at constant voltage: during deposition from the YSZ_L suspension, the current was observed to rise, whereas in the case of the YSZ_T suspension the current decreased markedly with deposition time. The YSZ_L film has been shown to be denser than the YSZ_T film. After sintering at 1350°C, it consisted of completely formed grains ranging in size from 1 to 5 μm. To remove surface pores in YSZ_T coatings, they should be sintered at a temperature of 1450°C. [ABSTRACT FROM AUTHOR]

Magnetic levitation has been always a very promising field. Due to its versatility, it has garnered interest in field energy harvesting, high speed transportation, and high precision micro-manipulation amongst other fields. However, its application within the sphere of additive manufacturing (AM) has been negligible. Thus, for the first time, the work conducted here works with the development of a novel technique utilizing magnetic levitation for stable suspension for AM. Current AM techniques are heavily dependent on building the part of a substrate. The substrate limits the use of multiple material nozzles and also requires significant post-processing. The use of the principle of magnetic levitation can bypass the need for this substrate. Primary emphasis is placed on the computation of eddy currents and Lorentz force produced from the magnetic levitation system, and also on finding the relevant parameters affecting several output parameters such as position of levitation, force experienced by the object suspended, etc. A temperature analysis is also conducted to ensure that the principles used here are valid. ANSYS Ansoft Maxwell modules are used to determine these input parameters. The work is subsequently validated through the transient module of the same module. The results presented here depict the viability of the system within the AM environment and the successful elimination of the need for a substrate. [ABSTRACT FROM AUTHOR]

Film-forming techniques and the control of heat release in micro-energetic chips or devices create challenges and bottlenecks for the utilization of energy. In this study, promising nano-Al/MoO3 metastable intermolecular composite (MIC) chips with an uniform distribution of particles were firstly designed via a convenient and high-efficiency electrophoretic deposition (EPD) technique at room temperature and under ambient pressure conditions. The mixture of isopropanol, polyethyleneimine, and benzoic acid proved to be an optimized dispersing agent for EPD. The kinetics of EPD for oxidants (Al) and reductants (MoO3) were systematically investigated, which contributed to adjusting the equivalence ratio of targeted energetic chips after changing the EPD dynamic behaviors of Al and MoO3 in suspension. In addition, the obtained nano-Al/MoO3 MIC energetic chips showed excellent heat-release performance with a high heat release of ca. 3340 J/g, and were successfully ignited with a dazzling flame recorded by a high-speed camera. Moreover, the fabrication method here is fully compatible with a micro-electromechanical system (MEMS), which suggests promising potential in designing and developing other MIC energetic chips or devices for micro-ignition/propulsion applications.

Black-odor water is a serious environmental issue in many developing counties. Iron sulfides and chromophoric dissolved organic matter are considered possible blackening substances. However, the specific type of blackening iron sulfides and the contributions of blackening substances are unclear. This study performed a laboratory simulation experiment to identify the blackening iron sulfides and quantify the contribution of blackening substances. The environmental conditions for forming blackening substances and their blackening process were also determined. We demonstrated that the black iron sulfide was mackinawite. Humic acid is another substance that absorbs light. The equivalent contributions of mackinawite and humic acid were 18.94 m -1 /mg Fe 2+ and 1.11 m -1 /mg DOC, respectively. A pH of more than 6 is a precondition for producing mackinawite. The production of black substances is the foundation of the blackening process, but the suspension of black substances is essential in causing water blackening. Fulvic acid stabilizes the suspension by changing the surface charge of blackening substances. Moreover, blackening substances can also be suspended with microbial flocs. Determining blackening substances and their role during the blackening process would allow for developing precise and targeted control technologies, improving urban water over the long term., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The domain kinetics during cyclic switching using electrodes of stable suspension of Ag nanoparticles and tap water was studied in single crystals of the relaxor ferroelectric strontium-barium niobate Sr0.61Ba0.39Nb2O6. Mathematical treatment of the set of instantaneous domain images and analysis of the switching current data by Kolmogorov-Avrami formula have been applied for characterization of the polarization reversal process. The change of the time constants during cyclic switching in the single domain area and the area with initial nanodomain structure has been attributed to relaxation of the bias field. The noticeable switching deceleration for suspension electrode was attributed to series resistance. [ABSTRACT FROM AUTHOR]

Abstract: Pharmaceutical preparation of a hydrophobic aldose reductase inhibitor 5-(3-ethoxy-4-pentyloxyphenyl)-2,4-thiazolidinedione (CT112) was investigated. CT112 dissolved in a basic solution with different kinds of polymers was neutralized by acid to obtain a suspension preparation. In particular, the addition of a polymer, hydroxypropyl methyl cellulose (HPMC) provided a stable CT112 suspension with a homogeneous particle size, and there seemed to be an optimal concentration of HPMC for the stable suspension. The addition of polysorbate 80 brought higher CT112 solubility in water, but did not provide a stable suspension. X-ray diffraction, IR spectrum, and thermal analysis revealed that the particles in the suspension with HPMC had lower degree of crystallinity, less hydrophobic particle surface, and lower melting point and decreased fusion enthalpy than the suspension without HPMC. These results suggested that the highly stable CT112 suspension could be attained by the adsorption of the polymer. [Copyright &y& Elsevier]

Given a suitable link map f into a manifold M, we constructed, in a previous publication, link homotopy invariants κ(f) and μ(f). In the present paper we study the case M=Sn×ℝm-n in detail. Here μ(f) turns out to be the starting term of a whole sequence μ(s)(f), s=0, 1,…, of higher μ-invariants which together capture all the information contained in κ(f). We discuss the geometric significance of these new invariants. In several instances we obtain complete classification results. A central ingredient of our approach is the homotopy theory of wedges of spheres. [ABSTRACT FROM AUTHOR]

Film-forming techniques and the control of heat release in micro-energetic chips or devices create challenges and bottlenecks for the utilization of energy. In this study, promising nano-Al/MoO3 metastable intermolecular composite (MIC) chips with an uniform distribution of particles were firstly designed via a convenient and high-efficiency electrophoretic deposition (EPD) technique at room temperature and under ambient pressure conditions. The mixture of isopropanol, polyethyleneimine, and benzoic acid proved to be an optimized dispersing agent for EPD. The kinetics of EPD for oxidants (Al) and reductants (MoO3) were systematically investigated, which contributed to adjusting the equivalence ratio of targeted energetic chips after changing the EPD dynamic behaviors of Al and MoO3 in suspension. In addition, the obtained nano-Al/MoO3 MIC energetic chips showed excellent heat-release performance with a high heat release of ca. 3340 J/g, and were successfully ignited with a dazzling flame recorded by a high-speed camera. Moreover, the fabrication method here is fully compatible with a micro-electromechanical system (MEMS), which suggests promising potential in designing and developing other MIC energetic chips or devices for micro-ignition/propulsion applications. [ABSTRACT FROM AUTHOR]

Solid oxide fuel cells (SOFCs) have been attracting considerable attention as prospective power sources with a variety of applications. Much current research is directed towards lowering the SOFC operating temperature in order to reduce the costs related to insulation, materials, start-up and degradation. Development of versatile technologies is required to fabricate a SOFC with a thin-film electrolyte membrane to decrease ohmic losses at reduced temperatures and to form graded electrodes that have superior electrochemical performance. Electrophoretic deposition (EPD) is one of the most technologically flexible and cost-effective methods currently available for the thin film formation. This review briefly highlights the fundamental regularities and mechanisms of EPD and shows the evolution of the mathematical model of EPD considering classical and recent studies in this area. It presents current approaches to overcoming the challenges in the realization of the EPD process such as the choice of dispersion medium and additives, preparation of stable suspensions, bubble-free deposition from aqueous suspensions, formation of substrates with optimized porosity and conductivity and deposition on non-conducting substrates. It also summarizes the latest advances in deposition of different SOFCs' functional layers (dense, porous and multilayered) and entire cell structures, including micro-tubular cells. • Fundamental regularities and mechanisms of the EPD process are discussed. • Effect of dispersants and additives on suspension stability is critically analysed. • Recent advances in EPD on conducting and non-conducting substrates are reviewed. • Performances of cathode and anode-supported SOFC formed using EPD are compared. • Trends in EPD of multilayered electrolytes and entire μSOFC structures are shown. [ABSTRACT FROM AUTHOR]

This paper presents the results of a comparative study of methods to prevent the loss of barium during the formation of thin-film proton-conducting electrolyte BaCe0.89Gd0.1Cu0.01O3−δ (BCGCuO) on La2NiO4+δ-based (LNO) cathode substrates by electrophoretic deposition (EPD). Three different methods of the BCGCuO film coating were considered: the formation of the BCGCuO electrolyte film without (1) and with a protective BaCeO3 (BCO) film (2) on the LNO electrode substrate and the formation of the BCGCuO electrolyte film on a modified La1.7Ba0.3NiO4+δ (LBNO) cathode substrate (3). After the cyclic EPD in six stages, the resulting BCGCuO film (6 μm) (1) on the LNO substrate was completely dense, but the scanning electron microscope (SEM) analysis revealed the absence of barium in the film caused by its intensive diffusion into the substrate and evaporation during the sintering. The BCO layer prevented the barium loss in the BCGCuO film (2); however, the protective film possessed a porous island structure, which resulted in the deterioration of the film's conductivity. The use of the modified LBNO cathode also effectively prevented the loss of barium in the BCGCuO film (3). A BCGCuO film whose conductivity behavior most closely resembled that of the compacts was obtained by using this method which has strong potential for practical applications in solid oxide fuel cell (SOFC) technology. [ABSTRACT FROM AUTHOR]