Operando XRD study of LiMn1.5Ni0.5O4 high-voltage cathode under high-rate charge-discharge reaction

Structural variation of LiMn1.5Ni0.5O4 spinel cathode during the Li+ extraction/insertion reaction was studied using operando X-ray diffraction. It was found that the reaction in the voltage range from 3.5 to 4.9 V consisted of two consecutive two-phase reactions, where three spinel phases of LiMn1.5Ni0.5O4, Li0.5Mn1.5Ni0.5O4 and Mn1.5Ni0.5O4 were identified and the lattice volume change in the whole reaction was evaluated as 6%. The reactions were symmetric and reversible under low-current conditions, but some asymmetries were detected during high current operation. Furthermore, a two-phase reaction between cubic and tetragonal phases was observed in the low-voltage reaction at 2.1–3.5 V, where the lattice volume change was approximately 4.9%. The rate-determining step was discussed based on these operando results.

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Kinetic pathways of ionic transport in fast-charging lithium titanate

Science ◽

10.1126/science.aax3520 ◽

2020 ◽

Vol 367 (6481) ◽

pp. 1030-1034 ◽

Cited By ~ 26

Author(s):

Wei Zhang ◽

Dong-Hwa Seo ◽

Tina Chen ◽

Lijun Wu ◽

Mehmet Topsakal ◽

...

Keyword(s):

Ground State ◽

Electrode Materials ◽

Rate Capability ◽

Lithium Titanate ◽

High Rate ◽

Phase Reaction ◽

Two Phase ◽

Fast Charging ◽

Kinetic Mechanisms ◽

Electron Energy Loss

Fast-charging batteries typically use electrodes capable of accommodating lithium continuously by means of solid-solution transformation because they have few kinetic barriers apart from ionic diffusion. One exception is lithium titanate (Li4Ti5O12), an anode exhibiting extraordinary rate capability apparently inconsistent with its two-phase reaction and slow Li diffusion in both phases. Through real-time tracking of Li+ migration using operando electron energy-loss spectroscopy, we reveal that facile transport in Li4+xTi5O12 is enabled by kinetic pathways comprising distorted Li polyhedra in metastable intermediates along two-phase boundaries. Our work demonstrates that high-rate capability may be enabled by accessing the energy landscape above the ground state, which may have fundamentally different kinetic mechanisms from the ground-state macroscopic phases. This insight should present new opportunities in searching for high-rate electrode materials.

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The Temperature-Phased Anaerobic Biofilter Process

Water Science & Technology ◽

10.2166/wst.1994.0483 ◽

1994 ◽

Vol 29 (9) ◽

pp. 213-223 ◽

Cited By ~ 5

Author(s):

Sandra K. Kaiser ◽

Richard R. Dague

Keyword(s):

System Performance ◽

Anaerobic Treatment ◽

Size Ratio ◽

High Rate ◽

Phase System ◽

Optimum Size ◽

Treatment Technology ◽

Two Phase ◽

In Series ◽

Two Temperature

The “temperature-phased anaerobic biofilter” or TPAB process (U.S. Patent pending), is a new high-rate anaerobic treatment system that includes a thermophilic (56°C) biofilter connected in series with a mesophilic (35°C) biofilter providing for two-temperature, two-phase treatment. Three TPAB systems of different thermophilic:mesophilic reactor size ratios were operated at system HRTs of 24 hrs, 36 hrs, and 48 hrs to characterize performance and to determine if an optimum size ratio exists between the thermophilic and mesophilic phases. The three TPAB systems achieved SCOD reductions in excess of 97% and TCOD reductions in excess of 90% for a synthetic milk substrate over a range of system COD loadings from 2 g COD/L/day to 16 g COD/L/day. There was little difference in performance between the three TPAB systems based on COD reduction and methane production. The 1:7 ratio of thermophilic:mesophilic phase TPAB system performed as well as the 1:3 and 1:1 size ratio TPAB systems. In applications of the process, a relatively small thermophilic first-phase can be used without sacrificing overall two-phase system performance. The TPAB process is a promising new anaerobic treatment technology with the ability to achieve higher efficiencies of organic removals than is generally possible for single-stage anaerobic filter systems operated at equivalent HRTs and organic loadings.

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Insulation Life Span of Low-Voltage Electric Motors—A Survey

Energies ◽

10.3390/en14061738 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1738

Author(s):

Vanessa Neves Höpner ◽

Volmir Eugênio Wilhelm

Keyword(s):

Life Span ◽

Electric Motor ◽

Low Voltage ◽

Frequency Converter ◽

Rate Of Change ◽

High Rate ◽

Switching Frequency ◽

Electric Motors ◽

Frequency Converters ◽

High Switching Frequency

The use of static frequency converters, which have a high switching frequency, generates voltage pulses with a high rate of change over time. In combination with cable and motor impedance, this generates repetitive overvoltage at the motor terminals, influencing the occurrence of partial discharges between conductors, causing degradation of the insulation of electric motors. Understanding the effects resulting from the frequency converter–electric motor interaction is essential for developing and implementing insulation systems with characteristics that support the most diverse applications, have an operating life under economically viable conditions, and promote energy efficiency. With this objective, a search was carried out in three recognized databases. Duplicate articles were eliminated, resulting in 1069 articles, which were systematically categorized and reviewed, resulting in 481 articles discussing the causes of degradation in the insulation of electric motors powered by frequency converters. A bibliographic portfolio was built and evaluated, with 230 articles that present results on the factors that can be used in estimating the life span of electric motor insulation. In this structure, the historical evolution of the collected information, the authors who conducted the most research on the theme, and the relevance of the knowledge presented in the works were considered.

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Numerical simulation of gas-solid two-phase reaction flow with multiple moving boundaries

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-01-2014-0018 ◽

2015 ◽

Vol 25 (2) ◽

pp. 375-390 ◽

Cited By ~ 7

Author(s):

Qiao Luo ◽

Xiaobing Zhang

Keyword(s):

Numerical Simulation ◽

Physical Phenomenon ◽

Great Influence ◽

Moving Boundaries ◽

Charge Weight ◽

Phase Reaction ◽

Two Phase ◽

Content Type ◽

One Dimensional ◽

Chamber Volume

Purpose – In engineering applications, gas-solid two-phase reaction flow with multi-moving boundaries is a common phenomenon. The launch process of multiple projectiles is a typical example. The flow of adjacent powder chambers is coupled by projectile’s motion. The purpose of this paper is to study this flow by numerical simulation. Design/methodology/approach – A one-dimensional two-phase reaction flow model and MacCormack difference scheme are implemented in a computational code, and the code is used to simulate the launch process of a system of multiple projectiles. For different launching rates and loading conditions, the simulated results of the launch process of three projectiles are obtained and discussed. Findings – At low launching rates, projectiles fired earlier in the series have little effect on the launch processes of projectiles fired later. However, at higher launching rates, the projectiles fired first have a great influence on the launch processes of projectiles fired later. As the launching rate increases, the maximum breech pressure for the later projectiles increases. Although the muzzle velocities increase initially, they reach a maximum at some launching rate, and then decrease rapidly. The muzzle velocities and maximum breech pressures of the three projectiles have an approximate linear relationship with the charge weight, propellant web size and chamber volume. Originality/value – This paper presents a prediction tool to understand the physical phenomenon of the gas-solid two-phase reaction flow with multi-moving boundaries, and can be used as a research tool for future interior ballistics studies of launch system of multiple projectiles.

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A two-phase system for the clean and high yield synthesis of furylmethane derivatives over –SO3H functionalized ionic liquids

Green Chemistry ◽

10.1039/c7gc01654a ◽

2017 ◽

Vol 19 (20) ◽

pp. 4804-4810 ◽

Cited By ~ 14

Author(s):

S. H. Shinde ◽

C. V. Rode

Keyword(s):

Ionic Liquids ◽

Reaction System ◽

High Yield ◽

Phase System ◽

Phase Reaction ◽

Two Phase ◽

Yield Production ◽

High Yield Production

A new and effective unique two-phase reaction system for the high yield production of tri(furyl)methane from furfural and furan.

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New Correlations for Critical and Subcritical Two-Phase Flow Through Surface Chokes in High-Rate Oil Wells

SPE Projects Facilities & Construction ◽

10.2118/120788-pa ◽

2010 ◽

Vol 5 (01) ◽

pp. 31-37 ◽

Cited By ~ 3

Author(s):

Hazim H. Al-Attar

Keyword(s):

Two Phase Flow ◽

Oil Wells ◽

High Rate ◽

Phase Flow ◽

Two Phase ◽

Flow Through

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Design of a Low-Noise, Fast Set-up and Low-Voltage Low-Dropout Regulator Featuring 230mA Load Current Range

10.36227/techrxiv.14636244 ◽

2021 ◽

Author(s):

Darshil Patel

Keyword(s):

Low Voltage ◽

Input Voltage ◽

Low Noise ◽

Cmos Process ◽

Transient Time ◽

Voltage Range ◽

Fast Transient ◽

Low Dropout Regulator ◽

Set Up ◽

Ldo Regulator

Low noise, high PSRR and fast transient low-dropout (LDO) regulators are critical for analog blocks such as ADCs, PLLs and RF SOC, etc. This paper presents design of low power, fast transient, high PSRR and high load-regulation low-dropout (LDO) regulator. The proposed LDO regulator is designed in 180nm. CMOS process and simulated in LTSpice and Cadence platform. The LDO proposed can support input voltage range up to 5V for loading currents up to 230mA. Measurements showed transient time or set-up time of less than 22µs, PSRR of ~66dB at 100kHz and >40dB at 1MHz and 0.8535mV of output voltage variation for a 0-230mA of load variation.

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Complex Electronic Protection for Low-voltage Three-phase Induction Motors

WSEAS TRANSACTIONS ON ELECTRONICS ◽

10.37394/232017.2020.11.2 ◽

2020 ◽

Vol 11 ◽

pp. 11-17

Author(s):

Gabriel Nicolae Popa ◽

Corina Maria Diniș

Keyword(s):

Induction Motors ◽

Low Voltage ◽

Short Circuit ◽

Electronic Devices ◽

General Purpose ◽

Two Phase ◽

Dc Voltage ◽

Electric Drives ◽

Normal Limits ◽

Three Phase

Low-voltage three-phase induction motors are most often used in industrial electric drives. Electric motors must be protected by electric and/or electronic devices against: short-circuit, overloads, asymmetrical currents, two-phase voltage operation, under-voltage, and over-temperature. To design the electronic protection currents, voltages and temperature must be measured to determine whether they fall within normal limits. The electronic protection was design into low capacity PLC. The paper presents the designs and analysis of complex electronic protection for general purpose low-voltage three-phase induction motors. The electronic protection has Hall transducers and conversion electronic devices for AC currents to DC voltages, AC voltages to DC voltage, temperature to DC voltage, a low capacity PLC, switches, motor’s power contactors, and signalling lamps has been developed. Experiments with complex electronic protection, for different faults are presented. The proposed protection has the advantages of incorporating all usual protections future for the low-voltage three-phase induction motors.

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I-V measurements of Ge-Se-Sn chalcogenide glassy alloys

Processing and Application of Ceramics ◽

10.2298/pac1501061k ◽

2015 ◽

Vol 9 (1) ◽

pp. 61-66 ◽

Cited By ~ 7

Author(s):

Vandana Kumari ◽

Anusaiya Kaswan ◽

Dinesh Patidar ◽

Narendra Saxena ◽

Kananbala Sharma

Keyword(s):

Elevated Temperatures ◽

Low Voltage ◽

Constant Load ◽

Dc Conductivity ◽

Voltage Range ◽

Glassy Alloys ◽

Current Voltage ◽

Maximum Current ◽

Current Voltage Characteristics ◽

Minimum Resistance

Current-voltage characteristics and DC electrical conductivity were studied for Ge30-xSe70Snx (x = 8, 11, 14, 17 and 20) glassy thin pellets of diameter 12mm and thickness 1mm prepared under a constant load of 5 tons using a well-known melt quenching technique in bulk as a function of composition. The I-V characteristics were recorded at room temperature as well as elevated temperatures up to 300?C. The experimental data suggests that glass containing 20 at.% of Sn has the minimum resistance allowing maximum current through the sample as compared to other counterparts of the series. Therefore, DC conductivity is found to increase with increasing Sn concentration. Composition dependence of DC conductivity is discussed in terms of the bonding between Se and Sn. Plots between ln I and V1/2 provide linear relationship for both low and high voltage range. These results have been explained through the Pool-Frenkel mechanism. The I-V characteristics show ohmic behaviour in the low voltage range and this behaviour turns to non-ohmic from ohmic in the higher voltage range due to voltage induced temperature effects.

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