High Efficiency Induction Research Articles

Synthesis of Chiral 3H‐Pyrrolo[1,2‐a]indoles Via Organocatalytic Enantioselective Addition of Alkynyl Biphenyl Quinone Methides

AbstractAn organocatalytic enantioselective reaction utilizing α‐[4‐(4‐hydroxyphenyl)phenyl]propargyl alcohols and 3‐substituted indoles has been successfully established for the synthesis of chiral 3H‐pyrrolo[1,2‐a]indoles. Through the assistance of an appropriate chiral phosphoric acid, a cascade sequence is facilitated, beginning with the dehydration of α‐[4‐(4‐hydroxyphenyl)phenyl]propargyl alcohols to form alkynyl 4,4’‐biphenyl quinone methides (4,4’‐BQMs). Subsequently, 1,12‐addition of 3H‐pyrrolo[1,2‐a]indoles to these alkynyl 4,4’‐BQMs results in the formation of allenes, which are then protonated and regenerate 4,4’‐BQMs. Finally, an enantioselective intramolecular annulation of 4,4’‐BQMs occurs smoothly, leading to the production of a range of 3H‐pyrrolo[1,2‐a]indoles with high efficiency and asymmetric induction.

High Efficiency Squirrel Cage Induction Machines

This paper highlights the benefits of replacing the classical cast aluminum cage with a cast copper cage in the manufacture of future generation of high efficiency induction machines used as motors or generators. The numerical analysis carried out in the paper is based on a 2D plane-parallel finite element approach of the induction machine, the numerical results being discussed and compared with experimental measurements.

Design and performance analysis of a high-efficiency Y3 induction motor

Induction motors have been applied in industrial domain, agriculture, transportation, national defence industry and other industries because of their advantages of simple structure, small inertia, low cost and long time working at high speed and high temperature. In this paper, particle swarm optimization algorithm (PSO) is applied to the optimal design of Y3 series asynchronous motors to achieve the highest efficiency. Secondly, the RMxprt module of Ansoft was used to design a Y3 high-efficiency induction motor with a certain power level using particle swarm optimization (PSO). Maxwell module was used to carry out finite element analysis to calculate the magnetic density and flux distribution of stator and rotor. The simulation results of stator current, flux, induction voltage and transient torque show that the performance indexes of Y3 induction motor designed in this paper meet the design requirements which verify the rationality of the design.

파라미터 학습을 통한 프리미엄 고효율 유도 전동기의 다중 목적 최적 설계

In this paper, the optimum design of a 3.7kW premium high-efficiency induction motor was proposed for reducing the cost using a low-grade iron core while maintaining the efficiency of the motor using a high-grade iron core. Global Response Surface Method(GRSM), one of the multi-objective optimization techniques, was used to satisfy the multi-objective optimization such as complex design problems with cost and production ranges. And GRSM performs the parallel analysis for accurate and efficient optimization search, including local and global search functions. In addition, the commercial optimization program HyperStudy and the electromagnetic FEM solver were used for the characteristic analysis of the motor. As a result of optimization, the price of optimum model was decreased 8% compared with the base model. The reliability of the proposed method was verified by the experiment.

Direct and Indirect Somatic Embryogenesis Induction in Camellia oleifera Abel.

Camellia oleifera Abel. is an important woody oil species; however, the shortage of rapid and industrialized seedling culture is a large constraint on the development of the tea oil industry. Somatic embryogenesis (SE) is one of the main powerful biotechnological tools for plant mass regeneration, but the largely unknown SE in C. oleifera limits the scale production of clonal plants. In this study, we described a high-efficiency SE system via direct and indirect pathways in C. oleifera and investigated the effect of genotype, explant age and phytohormones on SE. In the direct pathway, somatic embryos were highly induced from immature seeds 220 days after full blossom, and the development of embryoids was achieved with a combination of 0.19 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.05 mg/L thidiazuron (TDZ). In the indirect pathway, embryogenic calli were induced from the same explants in medium containing 1.5 mg/L 2,4-D, while 0.75 mg/L 2,4-D treatment led to high proliferation rates for embryogenic calli. The addition of 0.19 mg/L 2,4-D alone stimulated the production of globular embryos while causing a 75% loss of the induction rate in the heart embryo stage. Upon transfer of the globular embryos to phytohormone-free medium, an optimal induction rate of 62.37% from globular embryos to cotyledonary embryos was obtained. These data suggest that the subsequent differentiation process after the globular embryo stage in ISE is more similar to an endogenous phytohormones-driven process. Mature embryos germinated to produce intact plantlets on half-strength MS basal medium with a regeneration rate of 63.67%. Histological analysis confirmed the vascular bundle isolation of embryoids from the mother tissue. We further studied the different varieties and found that there were no significant genotype differences for SE induction efficiency in C. oleifera. Thus, we established a high-efficiency induction system for direct and indirect somatic embryogenesis (ISE) in C. oleifera and regenerated intact plantlets via SE, not organogenesis. ISE has a more complicated induction and regulatory mechanism than direct somatic embryogenesis. The improved protocol of SE would benefit mass propagation and genetic manipulation in C. oleifera.

Structural Optimizations of High-efficiency Direct-On-Line Synchronous Reluctance Motors for Metal Industry Applications

To meet the severe operating conditions in the metal industry, more thorough design and operational assessments about those implemented electric motors for specific applications must be emphasized. With its inherent robust structure, the induction motor is generally adopted to fulfill such driven objective. However, due to global warming and energy conservation concerns, those strictly enforced regulations have potentially increased the complexity and cost of high efficiency induction motor. Since the synchronous reluctance motor (SynRM) has relatively simpler structure with no copper loss in its rotor, it is a very attractive alternative for accomplishing the high-efficiency objectives of those common hoist, punch, roller, and pump applications. In addition, to eliminate drive circuits that can further reduce the overall system construction costs, the rotor barriers of the SynRM can be equipped with direct-on-line capability (DOL_SynRM) with conductors filled in. The impacts to the operational performance of these DOL_SynRMs for different applications will all be thoroughly investigated. The competitive high-efficiency DOL_SynRMs for driving various metal industry equipment can thus be offered.

Comparison of Commercial and Open-Source FEM Software: A Case Study

5-kW high-efficiency induction motor is analyzed using two-dimensional (2-D) open-source platform and the results are compared with commercial software and measurements. The importance of equivalent circuit parameters in 2-D analyses is highlighted. The noncommercial and commercial software give similar results. The motor is further analyzed in the 2.5-D domain and the results are compared with measured results. The losses obtained with 2-D, 2.5-D, and using the IEC segregation procedure of losses procedure are compared. The performance of an induction machine depends significantly on different parameters such as air gap and stator tooth tip height. Their impact on losses is studied with open-source finite-element analysis. The benefit of this open-source platform in the electrical motor analysis is the ability to use parallel-computing effectively and reduce the time required to solve the electromagnetic problem. Other benefits are the transparency of all features of the software and license-free usage. It is concluded that in 2-D analyses, the open-source software can be used on industrial-scale problems as it showed acceptable results for losses, and lower computational time when using appropriate mortar and conforming boundary conditions.

High‐efficiency flow‐through induction heating

This study reports a newly designed induction heating system for efficient, fast, and safe flow-through heating. The system has a very simple architecture, which is composed of a transmitting coil, an isolating plastic pipe, and an embedded metal shell. Wireless energy transfer from the external coil to the internal metal shell through the pipe is essential for decreasing losses. Also, a large contact surface between a fluid and the immersed shell enables rapid heat transfer. The proposed heating system was systematically investigated for different shell geometries and the results were compared with a commercially available conductive flow-through heating device. As a proof-of-concept demonstration, a prototype of the designed induction heating system was manufactured and the heating measurements were conducted with water. Power transfer efficiency of the prototyped induction heating system was measured to be 97%. The comparative study indicates that such high-efficiency induction flow-through heating system offers a great potential for replacing the conventional conductive heating device used in household applications in which the rapid and compact heating is desired.

Smart Surface-Enhanced Resonance Raman Scattering Nanoprobe for Monitoring Cellular Alkaline Phosphatase Activity during Osteogenic Differentiation.

High-efficiency induction of bone marrow mesenchymal stem cells (BMSCs) to osteogenic differentiation in vitro can help solve a series of bone diseases such as bone injury, fracture repair, and osteoporosis. In order to explore the optimal conditions for different chemical inducers to promote BMSCs differentiation and the possible differentiation mechanisms, we developed a smart nanoprobe that can achieve in situ alkaline phosphatase (ALP) activity detection during osteogenic differentiation in cells. The smart nanoprobe (Au@BCIP) was designed as the surface decoration of gold nanoparticles (AuNPs) with 5-bromo-4-chloro-3-indolyl phosphate (BCIP). The nanoprobe was co-cultured with differentiated BMSCs at different stages to monitor ALP activity based on an ALP-catalyzed hydrolysis reaction with BCIP as a substrate. The product can be quickly oxidized by dissolved oxygen to obtaina Raman-active species (5,5'-dibromo-4,4'-dichloro-1H,1H-[2,2'] biindolylidene-3,3'-dione). The SERS sensitivity was greatly improved by resonating the excitation wavelength of 632.8 nm. It is a new strategy for tracing bone disease-related ALP activity in an in vivo model with high sensitivity and selectivity and non-invasion. By using this nanoprobe, osteogenic differentiation of cells under osteogenic supplements was assessed and the p38 MAPK signaling pathway for osteogenic differentiation was experimentally evidenced, which are of significance for understanding BMSCs and regulating their osteogenic differentiation process.

High-Efficiency Induction Motor with Small Gap Length and Magnetic Wedges

The main purpose of our study is to improve efficiency of an induction motor. This paper describes a design approach to decrease stray load loss including loss due to structures (called fundamental losses) and PWM waveforms (called harmonic losses) using magnetic field analysis, where small air gap length and magnetic wedges were applied. It was clarified that reducing the air gap length and applying the magnetic wedges decreased both fundamental loss and harmonic losses. Therefore, the combination of the stray load loss and iron loss of the developed motor was 32% less than that of the conventional one. Moreover, the total loss of the developed motor was reduced by 63% compared with the conventional one, and its fficiency was increased from 95.5% to 96.8%.

Reliability Comparison Between Standard and High Efficiency Induction Motor Using Vector Control Method

Reliability Comparison Between Standard and High Efficiency Induction Motor Using Vector Control Method

Grain boundary engineering of power inductor cores for MHz applications

In this article we present the latest trends in processing, composition, theory, and utility of spinel ferrites for use as power inductor cores for a wide range of applications including power generation, conversion, and conditioning at MHz frequencies. Furthermore, it is a principle goal of this article to examine state of the art approaches and innovative methodologies to engineer grain boundary regions in composition, structure, and electrical and magnetic properties that allow spinel ferrites to operate at frequencies well above the state of technology (i.e., f > 1 MHz) with low core power loss while concomitantly maintaining high efficiency, high permeability and saturation induction.

Multi objective design of high efficiency induction motor using an analytical method's

Multi objective design of high efficiency induction motor using an analytical method's

Evaluation of manufacturers strategies to obtain high-efficient induction motors

This paper presents a study on how manufacturers are working to comply with the minimum energy performance standards in three-phase squirrel-cage induction-motors. One of the possibilities is to reduce the stator and rotor resistances, and to increase the magnetizing branch resistance. A method to obtain the parameters of the equivalent circuit of the induction motor from the catalog data sheet is shown. A new method to separate the short-circuit reactance in stator and rotor components, based on start-up and breakdown torques, is presented. The variation in rotor parameters as a function of the slip is conveniently accounted for. The proposed methodology is applied to several motors from different manufacturers of significant influence in the European market. The main parameters that affect losses and energy efficiency of motors are compared, establishing an idea on how each of these manufacturers acts to meet energy efficiency requirements.

MSX2 Initiates and Accelerates Mesenchymal Stem/Stromal Cell Specification of hPSCs by Regulating TWIST1 and PRAME

SummaryThe gap in knowledge of the molecular mechanisms underlying differentiation of human pluripotent stem cells (hPSCs) into the mesenchymal cell lineages hinders the application of hPSCs for cell-based therapy. In this study, we identified a critical role of muscle segment homeobox 2 (MSX2) in initiating and accelerating the molecular program that leads to mesenchymal stem/stromal cell (MSC) differentiation from hPSCs. Genetic deletion of MSX2 impairs hPSC differentiation into MSCs. When aided with a cocktail of soluble molecules, MSX2 ectopic expression induces hPSCs to form nearly homogeneous and fully functional MSCs. Mechanistically, MSX2 induces hPSCs to form neural crest cells, an intermediate cell stage preceding MSCs, and further differentiation by regulating TWIST1 and PRAME. Furthermore, we found that MSX2 is also required for hPSC differentiation into MSCs through mesendoderm and trophoblast. Our findings provide novel mechanistic insights into lineage specification of hPSCs to MSCs and effective strategies for applications of stem cells for regenerative medicine.

Firefly Algorithm Optimization of High Efficiency Induction Machine Using Inverse Problem

Firefly Algorithm Optimization of High Efficiency Induction Machine Using Inverse Problem

Analysis of Combined Motor Current Signature and Vibration-Monitoring Techniques in the Study of Broken Bars in Three-Phase High-Performance Induction Motors

Anomalies in operation of the motor modify harmonic content of motor supply current. Motor electrical current signature analysis (MCSA) is sensing an electrical signal containing current components. In this work, by introducing progressive failures to a healthy motor, we investigated the efficacy of combining motor current signature analysis with vibration-monitoring techniques for the detection of broken bars in the squirrel-cage rotors of three-phase high-efficiency induction motors, which are the new standard in Brazilian industry. Our results demonstrate that the combined approach improves reliability in the diagnosis of broken bars.

Reliability and Operation of High-Efficiency Induction Motors

Reliability and Operation of High-Efficiency Induction Motors

3ph High Efficiency Induction Motors with IFOC Applied to a Wheelchair by Joystick

Most of the wheelchair's drive systems uses direct-current (DC) motors as propulsion. However, such motors have several drawbacks aspects, as higher cost and maintenance, resulting in its gradual disuse. An option already consolidated in the industrial area is the high efficiency squirrel-cage induction motor, which has high energy efficiency and low maintenance, compared to DC motors. The use of induction motors applied to wheelchair tend to increase with the advancement of microelectronics and power electronics. This paper presents a relevant proposal in drive and control of power wheelchairs through three-phase induction with vector control. The system's power supply comes from batteries, which are suitable for the static converter. A digital signal controller (DSC) performs the reading joystick and vector control of three-phase induction motor. Experimental results with wheelchair developed denote viability and functionality for paraplegic patients.

Rotor Design for an Efficient Single-Phase Induction Motor for Refrigerator Compressors

This article describes a rotor making technology for the production of high-efficiency single-phase induction motors (SPIMs) to be used in refrigerator compressors. Rotors can have different aluminum fill factors according to the fabrication method. In order to examine the association between the fill factor and the efficiency of the rotor, we analyzed the distribution of magnetic flux density using the finite element method (FEM). Next, we made prototype rotors by conventional casting methods and by the proposed casting method and compared their fill factors. In addition, SPIMs were made using the rotors, and their efficiencies were measured using a dynamometer. Moreover, the SPIMs were put to use in a compressor, for testing, and for each SPIM the refrigerating capacity of the compressor was measured with a calorimeter. Based on the results of the FEM analysis of the magnetic flux density and the experiments, the reliability and validity of the proposed method were proven.