Simulation of a high frequency on/off valve actuated by a piezo-ring stack for digital hydraulics

Despite being widely used in several applications, commercially available spool valves, both servovalves and proportional valves, are inefficient components because they cause high power consumption due to the large pressure drops across the metering orifices. A recent research field aims at substituting spool valves with on/off valves having high switching frequency (changing state between open and closed in a few milliseconds or less) and producing low pressure drops, in order to make the so-called digital hydraulics possible. In spite of the advantages that it could provide, digital hydraulics does not have significative industrial applications yet, because of the difficulty in manufacturing such high frequency on/off valves. Hence, this paper performs a feasibility study of an on/off poppet-type valve actuated directly by a commercially available ring stack, which is a multilayer piezo-actuator capable of generating very high actuation forces needed for this application. Modulation of the average flow can be achieved by changing the duty cycle of the pulse width modulation (PWM) signal driving the piezostack. An inertance tube could also be used to smooth flow pulsation. The simulations obtained using a detailed Simulink model show that high switching frequency and very effective flow modulation can be obtained with this valve architecture along with low pressure drops and high flow rates, thus making it potentially suitable for digital hydraulics. The disadvantages of this single stage architecture are the large dimensions of the piezo stacks, and the high current generated because of both the high capacitance of the piezo stack and the high frequency switching. However, large-scale production of these components could help to reduce the costs, and the simulations show that limiting the maximum current to 10 A still provides good regulation.

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A Fractional-Order Element (FOE)-Based Approach to Wireless Power Transmission for Frequency Reduction and Output Power Quality Improvement

Electronics ◽

10.3390/electronics8091029 ◽

2019 ◽

Vol 8 (9) ◽

pp. 1029 ◽

Cited By ~ 3

Author(s):

Guidong Zhang ◽

Zuhong Ou ◽

Lili Qu

Keyword(s):

Fractional Order ◽

High Frequency ◽

Power Efficiency ◽

Power Transmission ◽

Switching Frequency ◽

Wireless Power ◽

Wireless Power Transmission ◽

High Switching Frequency ◽

Power Quality Improvement ◽

Power Inductors

A wireless power transmission (WPT) requires high switching frequency to achieve energy transmission; however, existing switching devices cannot satisfy the requirements of high-frequency switching, and the efficiency of current WPT is too low. Compared with the traditional power inductors and capacitors, fractional-order elements (FOEs) in WPT can realize necessary functions though requiring a lower switching frequency, which leads to a more favorable high-frequency switching performance with a higher efficiency. In this study, a generalized fractional-order WPT (FO-WPT) is established, followed by a comprehensive analysis on its WPT performance and power efficiency. Through extensive simulations of typical FO wireless power domino-resonators (FO-WPDRS), the functionality of the proposed FO-WPT for medium and long-range WPT is demonstrated. The numerical results show that the proposed FOE-based WPT solution has a higher power efficiency and lower switching frequency than conventional methods.

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Designing of Improved Series Resonant Inverter with FPGA Controller for Heating Applications

Journal of Circuits System and Computers ◽

10.1142/s0218126621500882 ◽

2020 ◽

pp. 2150088

Author(s):

S. Dhayanandh ◽

S. Manoharan

Keyword(s):

High Frequency ◽

Switching Frequency ◽

Zero Voltage Switching ◽

Resonant Inverter ◽

Series Resonance ◽

High Switching Frequency ◽

Series Resonant ◽

Higher Power ◽

Series Resonant Inverter ◽

And Control

Intensive utilization of Induction Heating (IH) innovations can be seen in numerous areas such as manufacturing industries, domestic or house hold and medicinal applications. The development of high switching frequency switches has encouraged the structure of high frequency inverters which are the key component of IH technology. Controlling the power output in a high frequency inverter for IH application is relatively complicated. This paper focuses on designing and developing a typical series resonance inverter and control it by FPGA-based controller. A MOSFET switch-based DC to AC converter is designed and Zero Voltage Switching (ZVS)-based switching strategy is accomplished to acquire less stress on switching devices and greater conversion efficiency. In this technique, secondary switched capacitor cell was proposed for resonant inverter of high frequency. To optimize the performance of the proposed inverter, the FPGA-based control system is implemented. Higher power density is the greatest advantage of this topology. The experimental and simulation model of the proposed series resonant inverter (SRI) for heating applications is developed and simulated using MATLAB/Simulink software.

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High-Level Production of a Thermostable Mutant of Yarrowia lipolytica Lipase 2 in Pichia pastoris

International Journal of Molecular Sciences ◽

10.3390/ijms21010279 ◽

2019 ◽

Vol 21 (1) ◽

pp. 279

Author(s):

Qinghua Zhou ◽

Zhixin Su ◽

Liangcheng Jiao ◽

Yao Wang ◽

Kaixin Yang ◽

...

Keyword(s):

Pichia Pastoris ◽

Yarrowia Lipolytica ◽

Large Scale ◽

Gene Dosage ◽

Life Time ◽

Industrial Applications ◽

Culture Conditions ◽

Scale Production ◽

Large Scale Production ◽

High Level

As a promising biocatalyst, Yarrowia lipolytica lipase 2 (YlLip2) is limited in its industrial applications due to its low thermostability. In this study, a thermostable YlLip2 mutant was overexpressed in Pichia pastoris and its half-life time was over 30 min at 80 °C. To obtain a higher protein secretion level, the gene dosage of the mutated lip2 gene was optimized and the lipase activity was improved by about 89%. Then, the YlLip2 activity of the obtained strain further increased from 482 to 1465 U/mL via optimizing the shaking flask culture conditions. Subsequently, Hac1p and Vitreoscilla hemoglobin (VHb) were coexpressed with the YlLip2 mutant to reduce the endoplasmic reticulum stress and enhance the oxygen uptake efficiency in the recombinant strains, respectively. Furthermore, high-density fermentations were performed in a 3 L bioreactor and the production of the YlLip2 mutant reached 9080 U/mL. The results demonstrated that the expression level of the thermostable YlLip2 mutant was predominantly enhanced via the combination of these strategies in P. pastoris, which forms a consolidated basis for its large-scale production and future industrial applications.

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Large scale production of uniform GaInP/GaAs structures by low pressure MOVPE in a multiwafer planetary reactor (solar cell manufacture)

The Conference Record of the Twenty-Second IEEE Photovoltaic Specialists Conference - 1991 ◽

10.1109/pvsc.1991.169260 ◽

2002 ◽

Author(s):

P. Schmitz ◽

J. Hergeth ◽

G. Strauch ◽

H. Juergensen

Keyword(s):

Solar Cell ◽

Large Scale ◽

Low Pressure ◽

Scale Production ◽

Large Scale Production

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Enhancing High-Frequency Dielectric Properties of Beta-SiC Filled Nanocomposites from Synergy between Percolation and Polarization

Materials ◽

10.3390/ma11091699 ◽

2018 ◽

Vol 11 (9) ◽

pp. 1699 ◽

Cited By ~ 1

Author(s):

Cheng Peng ◽

Yefeng Feng ◽

Jianbing Hu

Keyword(s):

Electrical Properties ◽

Polyvinyl Chloride ◽

High Frequency ◽

Vinyl Alcohol ◽

Large Scale ◽

Breakdown Strength ◽

Induced Polarization ◽

Poly Vinyl Alcohol ◽

Scale Production ◽

High Permittivity

Promising comprehensive properties, including high permittivity, low dielectric loss, high breakdown strength, low electrical conductivity, and high thermal conductivity, are very hard to simultaneously obtain in high-frequency applicable polymer nanocomposite dielectrics. Instead of traditional electric percolation, in this work, a novel route based on a synergy between electric percolation and induced polarization has been raised to prepare 0–3 type nanocomposites with an enhanced high permittivity (high-k) property and low loss at high frequency. This work aimed at optimizing that synergy to achieve the favorable properties mentioned above in composite dielectrics used at high frequencies such as 1 MHz and 1 GHz. Conductive beta-SiC nanoparticles with a particle size of ~30 nm were employed as filler and both insulating poly(vinyl alcohol) and polyvinyl chloride were employed as polymer matrices to construct two composite systems. Utilizing polyvinyl chloride rather than poly(vinyl alcohol) realizes higher comprehensive electrical properties in composites, ascribed to optimization of that synergy. The optimization was achieved based on a combination of mild induced polarization and polarization-assisted electric percolation. Therefore, this work might open the way for large-scale production of high-frequency applicable composite dielectrics with competitive comprehensive electrical properties.

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Polymer Brush Coating and Adhesion Technology at Scale

Polymers ◽

10.3390/polym12071475 ◽

2020 ◽

Vol 12 (7) ◽

pp. 1475 ◽

Cited By ~ 2

Author(s):

Kristian Birk Buhl ◽

Asger Holm Agergaard ◽

Mie Lillethorup ◽

Jakob Pagh Nikolajsen ◽

Steen Uttrup Pedersen ◽

...

Keyword(s):

Polymer Brushes ◽

High Performance ◽

Large Scale ◽

Polymer Brush ◽

Dissimilar Materials ◽

Industrial Applications ◽

Polymer Materials ◽

Full Potential ◽

Scale Production ◽

Precise Control

Creating strong joints between dissimilar materials for high-performance hybrid products places high demands on modern adhesives. Traditionally, adhesion relies on the compatibility between surfaces, often requiring the use of primers and thick bonding layers to achieve stable joints. The coatings of polymer brushes enable the compatibilization of material surfaces through precise control over surface chemistry, facilitating strong adhesion through a nanometer-thin layer. Here, we give a detailed account of our research on adhesion promoted by polymer brushes along with examples from industrial applications. We discuss two fundamentally different adhesive mechanisms of polymer brushes, namely (1) physical bonding via entanglement and (2) chemical bonding. The former mechanism is demonstrated by e.g., the strong bonding between poly(methyl methacrylate) (PMMA) brush coated stainless steel and bulk PMMA, while the latter is shown by e.g., the improved adhesion between silicone and titanium substrates, functionalized by a hydrosilane-modified poly(hydroxyethyl methacrylate) (PHEMA) brush. This review establishes that the clever design of polymer brushes can facilitate strong bonding between metals and various polymer materials or compatibilize fillers or nanoparticles with otherwise incompatible polymeric matrices. To realize the full potential of polymer brush functionalized materials, we discuss the progress in the synthesis of polymer brushes under ambient and scalable industrial conditions, and present recent developments in atom transfer radical polymerization for the large-scale production of brush-modified materials.

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Synthesis and characterization of Y2O3: Eu3+ powder phosphor by a hydrolysis technique

Journal of Materials Research ◽

10.1557/jmr.1998.0403 ◽

1998 ◽

Vol 13 (10) ◽

pp. 2950-2955 ◽

Cited By ~ 72

Author(s):

Yong Dong Jiang ◽

Zhong Lin Wang ◽

Fuli Zhang ◽

Henry G. Paris ◽

Christopher J. Summers

Keyword(s):

Electron Microscopy ◽

Large Scale ◽

Luminescent Properties ◽

Industrial Applications ◽

Europium Oxide ◽

Scale Production ◽

Experimental Conditions ◽

Luminescence Efficiency ◽

Transmission Electron ◽

Large Scale Production

A forced hydrolysis technique is used for preparing Y2O3: Eu3+ powders at low processing temperatures. The technique uses yttrium oxide, europium oxide, and nitric acid and urea, and has the potential for large-scale production for industrial applications. Several experimental conditions have been examined to optimize the luminescence efficiency. The best result was found to be at 2 mol% Eu doping and a 2 h firing of 1400 °C. Microstructural information provided by x-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) have been applied to interpret the observed luminescent properties.

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Production factors in the thermal processing of polyethylene and the problem of assessing their damaging effect on the body of workers

Kazan medical journal ◽

10.17816/kazmj64025 ◽

1998 ◽

Vol 79 (3) ◽

pp. 198-203

Author(s):

N. Kh. Amirov ◽

L.na R. Tukhvatullina

Keyword(s):

Thermal Processing ◽

Large Scale ◽

Low Pressure ◽

The Body ◽

Scale Production ◽

Production Factors ◽

Large Scale Production

Large-scale production and polyethylene processing enterprises in our country have been developing since the 60s. Since the early 1990s, the industry of polyolefins, including high and low pressure polyethylene (LDPE and HDPE) and polypropylene, has been ranked first in terms of production among other plastics.

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Hybrid Pulse Width Modulation Strategy of a High-Frequency Link Three-Phase Four-Leg Matrix Converter Based on Compensation Theory

Applied Sciences ◽

10.3390/app10010039 ◽

2019 ◽

Vol 10 (1) ◽

pp. 39

Author(s):

Rutian Wang ◽

Fuxu Wang ◽

Haining Pan ◽

Sutong Liu

Keyword(s):

High Frequency ◽

Pulse Width ◽

Pulse Width Modulation ◽

Matrix Converter ◽

Compensation Method ◽

Switching Frequency ◽

Control Logic ◽

Compensation Strategy ◽

High Switching Frequency ◽

Three Phase

A high-frequency link (HFL) three-phase four-leg matrix converter (MC) can output three-phase balanced voltage for unbalanced load conditions. It is an inverter with great development potential. This paper presents a hybrid pulse width modulation (HPWM) strategy for a four-wire matrix converter based on the fourth bridge leg compensation method. Firstly, the rear-stage topology of a high-frequency link three-phase four-leg matrix converter is decoupled into two sets of ordinary three-phase four-wire inverters. Then the compensation strategy is applied to separate the fourth bridge leg from the coupling of the ordinary inverter and realize its independent control. Under the theory of compensation, the fourth bridge leg plays a role in compensating the deviation of the neutral point potential when the load is unbalanced, the fourth bridge leg does not need to work when the load is balanced. Finally, the fourth bridge leg modulation wave obtained by the compensation method is combined with the front three bridge leg modulation waves to perform the coupling control using the hybrid pulse width modulation strategy. It has changed the problem that the previous hybrid pulse width modulation strategy cannot be directly applied to the four-wire matrix converter. This strategy is simple to control, without adding any auxiliary commutation detection circuitry, can effectively solve the inherent commutation problem in the bidirectional switch tube of the four-wire matrix converter. It simplifies the complexity of the system, reduced control cost, and high switching loss caused by high switching frequency. The fast adjustment function of compensation strategy makes the dynamic response performance of system under load fluctuation state more prominent, the harmonic distortion rate is smaller. The perfect combination of two strategies allows the high-frequency link three-phase four-leg matrix converter with any form of load to give full play to its structural advantages. The related work verifies the feasibility and effectiveness of the modulation method and control logic.

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