Accounting for material imperfections in the design and optimization of low cost Halbach magnets

2020 ◽  
Vol 91 (10) ◽  
pp. 103904
Author(s):  
A. Bogaychuk ◽  
V. Kuzmin
Keyword(s):  
Low Cost ◽  
Design And Optimization

scholarly journals Sensor Networks for Structures Health Monitoring: Placement, Implementations, and Challenges—A Review

Vibration ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 551-584
Author(s):  
Samir Mustapha ◽  
Ye Lu ◽  
Ching-Tai Ng ◽  
Pawel Malinowski
Keyword(s):  
Sensor Networks ◽  
Health Monitoring ◽  
Data Transmission ◽  
System Integration ◽  
Structural Integrity ◽  
Low Cost ◽  
Data Communication ◽  
Total Cost ◽  
Design And Optimization ◽  
Successful Case

The development of structural health monitoring (SHM) systems and their integration in actual structures has become a necessity as it can provide a robust and low-cost solution for monitoring the structural integrity of and the ability to predict the remaining life of structures. In this review, we aim at focusing on one of the important issues of SHM, the design, and implementation of sensor networks. Location and number of sensors, in any SHM system, are of high importance as they impact the system integration, system performance, and accuracy of assessment, as well as the total cost. Hence we are interested in shedding the light on the sensor networks as an essential component of SHM systems. The review discusses several important parameters including design and optimization of sensor networks, development of academic and commercial solutions, powering of sensors, data communication, data transmission, and analytics. Finally, we presented some successful case studies including the challenges and limitations associated with the sensor networks.

Design and Analysis of Thermoacoustic Refrigerators Using Air as Working Substance

2019 ◽  
Vol 27 (01) ◽  
pp. 1950008 ◽  
Author(s):  
B. G. Prashantha ◽  
S. Seetharamu ◽  
G. S. V. L. Narasimham ◽  
M. R. Praveen Kumar
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Low Cost ◽  
Design Strategies ◽  
Software Simulation ◽  
Design And Optimization ◽  
Theoretical Design ◽  
Resonator Design ◽  
Simulation Results ◽  
Thermoacoustic Refrigerators

In this paper, the design of 50 W thermoacoustic refrigerators operating with air as working substance at 10 bar pressure and 3% drive ratio for a temperature difference of 28 K is described. The design strategies discussed in this paper help in design and development of low cost thermoacoustic coolers compared to helium as the working substance. The design and optimization of spiral stack and heat exchangers, and the promising 0.2[Formula: see text] and 0.15[Formula: see text] resonator design with taper and divergent section with hemispherical end are discussed. The surface area, volume, length and power density of the hemispherical end design with air as working substance is found better compared to the published 10 and 50 W coolers using helium as the working substance. The theoretical design results are validated using DeltaEC software simulation results. The DeltaEC predicts 51.4% improvement in COP (1.273) at the cold heat exchanger temperature of [Formula: see text]C with air as working substance for the 50[Formula: see text]W 0.15[Formula: see text]TDH resonator design compared to the published 50[Formula: see text]W 0.25[Formula: see text]TDH resonator design with helium as working substance.

scholarly journals Design and Optimization of Piezoresistive PEO/PEDOT:PSS Electrospun Nanofibers for Wearable Flex Sensors

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2166
Author(s):  
Eve Verpoorten ◽  
Giulia Massaglia ◽  
Gianluca Ciardelli ◽  
Candido Fabrizio Pirri ◽  
Marzia Quaglio
Keyword(s):  
Low Cost ◽  
Electrospun Nanofibers ◽  
Strain Sensors ◽  
Active Materials ◽  
Design And Optimization ◽  
Piezoelectric Strain ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Poly Styrene Sulfonate ◽  
Flex Sensors

Flexible strain sensors are fundamental devices for application in human body monitoring in areas ranging from health care to soft robotics. Stretchable piezoelectric strain sensors received an ever-increasing interest to design novel, robust and low-cost sensing units for these sensors, with intrinsically conductive polymers (ICPs) as leading materials. We investigated a sensitive element based on crosslinked electrospun nanofibers (NFs) directly collected and thermal treated on a flexible and biocompatible substrate of polydimethylsiloxane (PDMS). The nanostructured active layer based on a blend of poly(ethylene oxide) (PEO) and poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) as the ICP was optimized, especially in terms of the thermal treatment that promotes electrical conductivity through crosslinking of PEO and PSS, preserving the nanostructuration and optimizing the coupling between the sensitive layer and the substrate. We demonstrate that excellent properties can be obtained thanks to the nanostructured active materials. We analyzed the piezoresistive response of the sensor in both compression and traction modes, obtaining an increase in the electrical resistance up to 90%. The Gauge Factors (GFs) reflected the extraordinary piezoresistive behavior observed: 45.84 in traction and 208.55 in compression mode, which is much higher than the results presented in the literature for non-nanostructurated PEDOT.

scholarly journals Design and optimization of cost-effective coldproof portable enclosures for polar environment

2020 ◽  
Vol 10 (6) ◽  
pp. 6251
Author(s):  
Behzad Parsi ◽  
Lihong Zhang
Keyword(s):  
Control System ◽  
Integrated Circuits ◽  
Fuzzy Logic Controller ◽  
Low Cost ◽  
Electronic Devices ◽  
Industrial Applications ◽  
The Other ◽  
International Electrotechnical Commission ◽  
Design And Optimization ◽  
Thermal Resistors

Based on the International Electrotechnical Commission standards, the electronic devices in the industrial class (e.g., integrated circuits or batteries) can only operate at the ambient temperature between -40°C and 85°C. For the human-involved regions in Alaska, Northern Canada, and Antarctica, extreme cold condition as low as -55°C might affect sensing electronic devices utilized in the scientific or industrial applications. In this paper, we propose a design and optimization methodology for the self-heating portable enclosures, which can warm up the inner space from -55°C for encasing the low-cost industrial-class electronic devices instead of expensive military-class ones to work reliably within their allowed operating temperature limit. Among the other options, ceramic thermal resistors are selected as the heating elements inside the enclosure. The placement of the thermal resistors is studied with the aid of thermal modelling for the single heating device by using the curve fitting technique to achieve uniform temperature distribution within the enclosure. To maintain the inner temperature above -40°C but with the least power consumption from the thermal resistors, we have developed a control system based on the fuzzy logic controller. For validation, we have utilized COMSOL Multiphysics software and then one prototyped enclosure along with the fuzzy control system. Our experimental measurement exhibits its efficacy compared to the other design options.

scholarly journals Nanostructured Electrode Enabling Fast and Fullyreversible MnO2-to-Mn2+ Conversion in Mild Buffered Aqueous Electrolytes

2020 ◽  
Author(s):  
Mickaël Mateos ◽  
Kenneth D. Harris ◽  
Benoit Limoges ◽  
Véronique Balland
Keyword(s):  
Rational Design ◽  
Coulombic Efficiency ◽  
Low Cost ◽  
Active Material ◽  
Rate Capability ◽  
Conversion Reaction ◽  
Design And Optimization ◽  
Aqueous Conditions ◽  
Comprehensive Framework ◽  
Aqueous Batteries

On account of their low-cost, earth abundance, eco-sustainability, and high theoretical charge storage capacity, MnO<sub>2</sub> cathodes have attracted a renewed interest in the development of rechargeable aqueous batteries. However, they currently suffer from limited gravimetric capacities when operating under the preferred mild aqueous conditions, which leads to lower performance as compared to similar devices operating in strongly acidic or basic conditions. Here, we demonstrate how to overcome this limitation by combining a well-defined 3D nanostructured conductive electrode, which ensures an efficient reversible MnO<sub>2</sub>-to-Mn<sup>2+</sup> conversion reaction, with a mild acid buffered electrolyte (pH 5). A reversible gravimetric capacity of 560 mA·h·g<sup>-1</sup> (close to the maximal theoretical capacity of 574 mA·h·g<sup>-1</sup> estimated from the MnO<sub>2</sub> average oxidation state of 3.86) was obtained over rates ranging from 1 to 10 A·g<sup>-1</sup>. The rate capability was also remarkable, demonstrating a capacity retention of 435 mA·h·g<sup>-1</sup> at a rate of 110 A·g<sup>-1</sup>. These good performances have been attributed to optimal regulation of the mass transport and electronic transfer between the three process actors, <i>i.e.</i> the 3D conductive scaffold, the MnO<sub>2</sub> active material filling it, and the soluble species involved in the reversible conversion reaction. Additionally, the high reversibility and cycling stability of this conversion reaction is demonstrated over 900 cycles with a Coulombic efficiency > 99.4 % at a rate of 44 A·g<sup>-1</sup>. Besides these good performances, also demonstrated in a Zn/MnO<sub>2</sub> cell configuration, we discuss the key parameters governing the efficiency of the MnO<sub>2</sub>-to-Mn<sup>2+</sup> conversion. Overall, the present study provides a comprehensive framework for the rational design and optimization of MnO<sub>2</sub> cathodes involved in rechargeable mild aqueous batteries.

scholarly journals Study on the Forming Process and Deformation Behavior of Inner Ring in the Wheel Hub Bearing Based on Riveting Assembly

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3785
Author(s):  
Wei Xiong ◽  
You Wang ◽  
Xiao-Ping Li ◽  
Song Mei ◽  
Zhu-Xin Tian
Keyword(s):  
Deformation Behavior ◽  
High Efficiency ◽  
Low Cost ◽  
Clamping Force ◽  
Forming Process ◽  
Design And Optimization ◽  
Bearing Clearance ◽  
Riveting Process ◽  
Research Findings ◽  
Simulation Results

The orbital riveting process has been successively adopted in the assembly of wheel hub bearing, due to its special merits of high efficiency, low cost, and so on. The forming process and deformation behavior of the inner ring have significant influence on the axial clamping force and bearing clearance, however, which haven’t been addressed yet. In this study, a numerical simulation platform for the assembly of the hub bearing is established by the joint use of the static implicit and dynamic explicit algorithms. Based on the platform, the deformation process and deformation behavior of the inner ring are investigated, along with the interference assembly and riveting assembly on the loading process of the inner ring. Finally, relevant experimental verifications are carried out to consolidate the simulation results. The research findings could be used to guide the design and optimization of the axial clamping force and bearing clearance.

scholarly journals Rectifiers’ Design and Optimization for a Dual-Channel RF Energy Harvester

2020 ◽  
Vol 10 (2) ◽  
pp. 11
Author(s):  
Davide Colaiuda ◽  
Iolanda Ulisse ◽  
Giuseppe Ferri
Keyword(s):  
Low Cost ◽  
Schottky Diodes ◽  
Input Power ◽  
Design And Optimization ◽  
Radio Frequency Energy ◽  
Dual Channel ◽  
A Value ◽  
Lumped Elements ◽  
Commercial Device ◽  
Load Pull

This paper presents the design and implementation of two front-ends for RF (Radio Frequency) energy harvesting, comparing them with the commercial one—P2110 by Powercast Co. (Pittsburgh, PA, USA) Both devices are implemented on a discrete element board with microstrip lines combined with lumped elements and are optimized for two different input power levels (−10 dBm and 10 dBm, respectively), at the GSM900 frequencies. The load has been fixed at 5kΩ, after a load-pull analysis on systems. The rectifiers stages implement two different Schottky diodes in two different topologies: a single diode and a 2-stage Dickson’s charge pump. The second one is compared with the P2110 by generating RF fields at 915 MHz with the Powercast Powerspot. The main aim of this work is to design simple and efficient low-cost devices, which can be used as a power supply for low-power autonomous sensors, with better performances than the current solutions of state-of-the-art equipment, providing an acceptable voltage level on the load. Measurements have been conducted for input power range −20 dBm up to 10 dBm; the best power conversion efficiency (PCE) is obtained with the second design, which reaches a value of 70% at 915 MHz. In particular, the proposed device exhibited better performance compared to the P2110 commercial device, allowing a maximum distance of operation of up to 22 meters from the dedicated RF power source, making it suitable even for IoT (Internet of Things) applications.

scholarly journals Electromechanical Behaviors of Graphene Reinforced Polymer Composites: A Review

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 528 ◽  
Author(s):  
Chuang Feng ◽  
Dong Zhu ◽  
Yu Wang ◽  
Sujing Jin
Keyword(s):  
Polymer Composites ◽  
Smart Materials ◽  
Low Cost ◽  
Experimental Examination ◽  
Engineering Structures ◽  
Design And Optimization ◽  
Mechanical And Electrical Properties ◽  
Reinforced Polymer ◽  
Smart Materials And Structures ◽  
Pros And Cons

Graphene (including its derivatives)-reinforced polymer composites (GRPCs) have been drawing tremendous attention from academic and industrial communities for developing smart materials and structures. Such interest stems from the excellent combination of the mechanical and electrical properties of these composites while keeping the beneficial intrinsic attributes of the polymers, including flexibility, easy processability, low cost and good biological and chemical compatibility. The electromechanical performances of these GRPCs are of great importance for the design and optimization of engineering structures and components. Extensive work has been devoted to this topic. This paper reviews the recent studies on the electromechanical behaviors of GRPCs. First the methods and techniques to manufacture graphene and GRPCs are introduced, in which the pros and cons of each method are discussed. Then the experimental examination and theoretical modeling on the electromechanical behaviors of the nanocomposites are presented and discussed.

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