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Conceptual design and analysis for a novel parallel configuration-type wave energy converter

RENEWABLE ENERGY 2023年第1期208卷 627-644页

作者： Zhang, Yongxing Huang, Zhicong Zou, Bowei Bian, Jing South China Univ Technol Shien Ming Wu Sch Intelligent Engn Guangzhou 511442 Peoples R China Chongqing Univ Sch Civil Engn Chongqing 400044 Peoples R China

Oscillating body wave energy converter (OBWEC) is an essential way to exploit wave energy. Existing OBWECs with a single degree of freedom (DOF) suffer from a low energy conversion ratio. Although this power generation limit of OBWECs can be alleviated by increasing DOF, for the multi-DOF OBWEC, specific structure design guidelines, accurate energy conversion modeling and economic cost-related performance analysis at the conceptual design stage are still missing. To address this gap, this study proposes a novel parallel configuration WEC (PCWEC) with the idea of combining the advantages of multi-DOF OBWEC and parallel structure. The PCWEC energy conversion model is established under irregular wave states. Furthermore, we propose an energy costefficiency indicator and perform the performance comparison analysis and simulation experiments. Compared with typical OBWECs, results validate that the proposed PCWEC has the following advantages: (i) a significant power generation increase under the same device scale, (ii) greater optimal output power by power take-off control, and (iii) higher energy cost-efficiency under changing wave states. Such a novel PCWEC design concept improves the current OBWEC's power generation performance and application prospect and offers certain guidance for the future commercial development of OBWECs.

关键词： Ocean wave energy Wave energy converter parallel configuration Energy conversion

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Graphene-Based Planar On-Chip Micro-Supercapacitors with Whole Series/parallel configuration for Integration

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INTEGRATED FERROELECTRICS 2019年第1期199卷 95-104页

作者： Liu, Lin-Jing Liu, Chun-Feng Li, Xiang Wang, Shu Wu, Feng-Min Zhang, Guang-Yu Harbin Univ Sci & Technol Sch Sci Harbin Heilongjiang Peoples R China

The development of high-performance micro-supercapacitors is conducive to the growth of modern micro-electronic systems. However, it is still a great challenge to fabricate micro-supercapacitors with high output potential/current for integration. Here we demonstrate the whole fabrication of planar on-chip micro-supercapacitors (POMSs) based on reduced graphene oxide (RGO) films, produced by photolithography techniques, with whole series/parallel configuration. The RGO films have good surface morphologies, uniform thickness (6 +/- 1.073 nm) and high conductivity (649.8 S cm(-1)) after hydroiodic acid treatment. Moreover, the operating potential of the RGO-POMS with whole series configuration has been obviously improved, which is two times that of a interdigital unit. The RGO-POMS with whole parallel configuration has larger current and better electrochemical performance than a single unit. Therefore, POMSs with whole series/parallel configuration have a good application foreground in the continuous development of integrated micro-devices.

关键词： Series parallel configuration integration on-chip micro-supercapacitors

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Analysis of a hydraulic coupling system for dual oscillating foils with a parallel configuration

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ENERGY 2018年 143卷 273-283页

作者： Ma, Penglei Wang, Yong Xie, Yudong Zhang, Jianhua Shandong Univ Sch Mech Engn Jinan 250061 Shandong Peoples R China Shandong Univ Minist Educ Key Lab High Efficiency & Clean Mech Mfg Jinan 250061 Shandong Peoples R China

The generators using oscillating foil to extract tidal energy have obvious advantages in shallow water. To get rid of the complicated control system, we proposed a hydraulic system to couple dual foils and realize the self-sustained oscillation motion of the foil. The coupling equations related to the foils' motion and hydrodynamic are established. Computations are performed using the software Fluent with a NACA0015 foil. A User Defined Function is compiled for iteration. The classical Runge-Kutta method is employed to compute the displacement and moving velocity. Computation results demonstrate that the hydraulic coupling system realizes well the self-sustained oscillation motion of foil instead of external control. The response of the coupling system is independent of the initial pitching angle. The damping coefficients have a significant effect on the response of coupling system. The response of coupling system, oscillation amplitude and frequency, declines with the increasing of damping coefficient, especially at relatively low damping coefficient. The energy consumption of pitching motion most appears in the stage of angle decrease. The evolutions of time-averaged power coefficient and energy harvesting efficiency versus damping coefficient are quite similar to that of the oscillation amplitude and frequency. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： Oscillating foil Hydraulic system Self-sustained Dual foils parallel configuration Energy harvesting

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A novel parallel configuration of dye-sensitized solar cells with double-sided anodic nanotube arrays

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ENERGY & ENVIRONMENTAL SCIENCE 2011年第6期4卷 2240-2248页

作者： Sun, Lidong Zhang, Sam Wang, Xiu Sun, Xiao Wei Ong, Duen Yang Kyaw, Aung Ko Ko Nanyang Technol Univ Sch Mech & Aerosp Engn Singapore 639798 Singapore Nanyang Technol Univ Sch Mat Sci & Engn Singapore 639798 Singapore Nanyang Technol Univ Sch Elect & Elect Engn Singapore 639798 Singapore

In dye-sensitized solar cells based on anodic titania nanotube arrays, the low photocurrent in the backside-illuminated configuration has hindered their development. To increase the energy absorption and thus promote the photocurrent, a novel parallel configuration of dye-sensitized solar cells is proposed and achieved in this work on the basis of double-sided anodic nanotubes. The parallel connection is verified by electrochemical impedance spectroscopy measurements. The parallel cells exhibit an average 70% increment in photocurrent and 30% enhancement in efficiency as compared to the single cells, due to significantly increased surface area and highly reduced series resistance. Theoretical calculation and experimental fitting results demonstrate that a tube length of similar to 30 mu m is optimal for the nanotubes used in this study with backside-illuminated architecture.

关键词： solar cells Dye-sensitized solar cells Nanotubes Photocurrent energy absorption parallel configuration parallel Connection SINGLE CELL pipe length impedance spectroscopy Anodic surface area Series Resistance

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Optimized fuzzy controller for a power-torque distribution in a hybrid vehicle with a parallel configuration

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART D-JOURNAL OF AUTOMOBILE ENGINEERING 2014年第14期228卷 1654-1674页

作者： Derakhshan, Mohsen Shirazi, Kourosh Heidari Shahid Chamran Univ Ahvaz Dept Mech Engn Ahvaz Iran

In this study, an optimized fuzzy controller was designed for a power-torque distribution in a hybrid passenger vehicle using the bees algorithm. For this purpose, a dynamic model for a parallel hybrid vehicle, including an internal-combustion engine, an electric motor and battery, a torque converter, a continuously variable transmission, torque-speed coupling and wheels (forward dynamic), is built. To simulate the driver's skill and performance when facing different conditions, a fuzzy controller (which is called the first-layer controller) is used. On the one hand, decisions made by the first-layer controller are a function of the desired acceleration, the desired speed and the speed error and, on the other hand, they depend on the vehicle's performance mode. The vehicle's performance mode is determined with regard to the charged condition (the state of charge) of the batteries, the vehicle's required power and the driver commands by another fuzzy controller which is called the second-layer controller. The necessary commands for the subsystems such as the throttle angle, the controller command for the electric motor and the appropriate speed ratio in the continuously variable transmission are determined by another controller, called the third-layer controller. Both the first layer and the second layer are optimized using the bees algorithm. According to the results, the optimized controller indicates an appropriate performance based on the defined rules in different situations. It also improves the vehicle's performance parameter and decreases the fuel consumption and the pollutions produced by the engine.

关键词： Optimized fuzzy controller torque distribution strategy hybrid electric vehicle parallel configuration bees algorithm

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Seven-day artificial lung testing in an in-parallel configuration

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ANNALS OF THORACIC SURGERY 2007年第3期84卷 988-994页

作者： Sato, Hitoshi Griffith, Grant W. Hall, Candice M. Toomasian, John M. Hirschl, Ronald B. Bartlett, Robert H. Cook, Keith E. Univ Michigan Dept Surg Ann Arbor MI 48109 USA

Background. A thoracic artificial lung, the MC3 Biolung, is being developed as a bridge to lung transplantation or as a treatment for acute respiratory insufficiency. Methods. The thoracic artificial lung was tested in 10 sheep with the goal of 7 days of respiratory support. The sheep were recovered from surgery and monitored awake for 7 days. Hemodynamics, blood gases, blood cell counts, and organ function were recorded, and after 7 days, all sheep were euthanized and necropsied. Results. Seven sheep survived the full duration. Cardiac output and mean arterial blood pressure were unchanged, averaging 4.7 +/- 0.8 L/min and 98 +/- 10 mm Hg, respectively. Arterial oxygen tension and device oxygen transfer rate were also unchanged, averaging 110 +/- 26 mm Hg and 97.7 +/- 35 mL/min, respectively. Arterial carbon dioxide tension was within normal ranges during the entire experiment, averaging 37.4 +/- 3.8 mm Hg. Artificial lung blood flow decreased from 51% +/- 14% of cardiac output on day 1 to 30% +/- 16% by day 7 because of changes in natural and artificial lung resistance. White blood cell counts were significantly elevated on days 5 and 7, and lastly, kidney and liver function remained normal, although signs of kidney infarction or hemorrhage were noted. Conclusions. The thoracic artificial lung is suitable for 7-day attachment, but improvements in blood biocompatibility are warranted.

关键词： Animals Artificial Organs Blood Coagulation Blood Pressure Heart Rate 动物人工器官血液凝固血压心率炎症肾肺绵羊时间因素 artificial lung Artificial Organs Cardiac Output Prosthesis parallel configuration Vital Signs Lung Transplantation Heart Rate

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parallel configuration terahertz metasurface

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OPTICS COMMUNICATIONS 2023年 529卷

作者： Jiu-sheng, Li Yi, Chen China Jiliang Univ Ctr THz Res Hangzhou 310018 Peoples R China

Coding metasurfaces have offered considerable abilities of freedom manipulation electromagnetic waves. Most of reported works exhibit that the coding metasurfaces are composed of coding particles in terms of a certain coding sequences or random digital sequence generated by MATLAB. Generally, these methods of designing metasurfaces are a time-consuming and considerably challenging process for researchers. Herein, we propose a novel terahertz metasurface structure which consists of coding supercells in parallel. The coding element is a sandwich structure made of two identical metal pattern layers and silicon dioxide layer. Under the incidence of right-handed circularly polarized (RCP) terahertz wave, the proposed parallel metasurface realizes vortex beam with topological charge of l = 1 and symmetrical four beam splitting. The structure provides a new simple and easy method for the design of terahertz metasurface devices and has a wide application prospect in terahertz system.

关键词： Terahertz wave Orbital angular momentum parallel configuration Four beam splitting

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Mitigation of 180Hz Midpoint Voltage Ripple in Vienna Rectifiers for Water Electrolysis using a parallel configuration 13

Mitigation of 180Hz Midpoint Voltage Ripple in Vienna Rectif...

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13th International Conference on Renewable Energy Research and Applications

作者： Kim, HaeIn Kim, Hag-Wone KNUT Korea Natl Univ Transportat Dept Elect Engn Chungju Chungcheongbuk South Korea

ISBN: (纸本)9798350375596;9798350375589

This paper proposes a novel method to mitigate the 180Hz voltage ripple at the DC-Link midpoint of Vienna rectifiers. Conventional solutions involve altering switching states or adding compensating circuits, which increase complexity and cost. In this study, a parallel configuration is introduced, where one module is connected to the a, b, c phases, and the other to the -c, -a, -b phases, effectively canceling the 180Hz ripple. This approach reduces the ripple without additional control strategies or circuits, providing a simpler and more economical solution, as validated through simulation.

关键词： Vienna Rectifier Midpoint Voltage Ripple parallel configuration Harmonic cancellation Voltage Balancing

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Magnetic shielding investigation for a 6 MV in-line linac within the parallel configuration of a linac-MR system

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MEDICAL PHYSICS 2012年第2期39卷 788-797页

作者： Santos, D. M. St Aubin, J. Fallone, B. G. Steciw, S. Univ Alberta Med Phys Div Dept Oncol Edmonton AB T6G 1Z2 Canada Univ Alberta Dept Phys Edmonton AB T6G 2G7 Canada Cross Canc Inst Dept Med Phys Edmonton AB T6G 1Z2 Canada

Purpose: In our current linac-magnetic resonance (MR) design, a 6 MV in-line linac is placed along the central axis of the MR's magnet where the MR's fringe magnetic fields are parallel to the overall electron trajectories in the linac waveguide. Our previous study of this configuration comprising a linac-MR SAD of 100 cm and a 0.5 T superconducting (open, split) MR imager. It showed the presence of longitudinal magnetic fields of 0.011 T at the electron gun, which caused a reduction in target current to 84% of nominal. In this study, passive and active magnetic shielding was investigated to recover the linac output losses caused by magnetic deflections of electron trajectories in the linac within a parallel linac-MR configuration. Methods: Magnetic materials and complex shield structures were used in a 3D finite element method (FEM) magnetic field model, which emulated the fringe magnetic fields of the MR imagers. The effects of passive magnetic shielding was studied by surrounding the electron gun and its casing with a series of capped steel cylinders of various inner lengths (26.5-306.5 mm) and thicknesses (0.75-15 mm) in the presence of the fringe magnetic fields from a commercial MR imager. In addition, the effects of a shield of fixed length (146.5 mm) with varying thicknesses were studied against a series of larger homogeneous magnetic fields (0-0.2 T). The effects of active magnetic shielding were studied by adding current loops around the electron gun and its casing. The loop currents, separation, and location were optimized to minimize the 0.011 T longitudinal magnetic fields in the electron gun. The magnetic field solutions from the FEM model were added to a validated linac simulation, consisting of a 3D electron gun (using OPERA-3d/SCALA) and 3D waveguide (using COMSOL Multiphysics and PARMELA) simulations. PARMELA's target current and output phase-space were analyzed to study the linac's output performance within the magnetic shields. Results: The FEM m

关键词： linac-MR magnetic shield longitudinal fringe magnetic fields parallel configuration electron gun simulations FEM

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Development of a transient analytical method for multi-pipe earth-to-air heat exchangers with parallel configuration

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JOURNAL OF BUILDING ENGINEERING 2023年 73卷

作者： Minaei, Asgar Rabani, Reza Univ Mohaghegh Ardabili Fac Engn Dept Mech Engn Ardebil Iran Islamic Azad Univ Dept Mech Engn Karaj Branch Karaj Iran

A novel analytical model for calculating the thermal performance of multi-pipe earth-to-air heat exchangers is presented by considering soil thermal saturation as well as soil temperature fluctuations on the ground surface. The accuracy of the analytical model is validated using a threedimensional numerical simulation. The proposed analytical model shows a great coincidence compared to the numerical simulation as well as already reported experimental data. Using this analytical approach, a three-pipe earth-to-air heat exchanger in realistic working conditions is simulated and the effect of the center-to-center distance of pipes on the outlet air temperature and averaged cooling capacity are also investigated. It is shown that while decreasing the distance between the pipes does not change the temperature of the outlet air in the initial working days, a reduction in the thermal performance is observed as the simulation proceeds. This can be attributed to the soil thermal saturation around the middle pipe. The average cooling capacity of the middle pipe reduces by 48%, 35%, 19%, 5%, 2%, and 1% with respect to a single-pipe earthto-air heat exchanger system for the distance of 25, 50, 100, 200, 250 and 300 cm between the pipes, respectively. In addition, it is shown that increasing the air velocity through the pipes enhances the cooling capacity, especially for larger pipes distance. The cooling capacity of the earth-to-air heat exchanger is enhanced as a result of the increment in the soil thermal conductivity in such a way that the increment percentage is higher for smaller pipe distances. The appropraite distance between the pipes is also shown to be related to the soil thermal conductivity. It is shown that for soil with thermal conductivity of 0.5 and 2 W/m.K, the appropraite distance becomes 200 cm and 300 cm, respectively.

关键词： Multi-pipe EAHE parallel configuration Analytical model Soil thermal saturation

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