Water-Jet Cavitation Shock Bulging as Novel Microforming Technique

AbstractWith the continuous expansion of the application range of microelectromechanical systems, microdevice forming technology has achieved remarkable results. However, it is challenging to develop new microforming processes that are low cost, environmentally friendly, and highly flexible; the high-energy shock wave in a cavitation bubble’s collapse process is used as the loading force. Herein, a new process for the microbulging of the water-jet cavitation is proposed. A series of experiments involving the water-jet cavitation shock microbulging process for TA2 titanium foil is performed on an experimental system. The microforming feasibility of the water-jet cavitation is investigated by characterizing the shape of the formed part. Subsequently, the effects of the main parameters of the water-jet cavitation on the bulging profile, forming depth, surface roughness, and bulging thickness distribution of TA2 titanium foil are revealed. The results show that the plastic deformation increases nonlinearly with the incident pressure. When the incident pressure is 20 MPa, the maximum deformation exceeds 240 μm, and the thickness thinning ratio changes within 10%. The microbulging feasibility of water-jet cavitation is verified by this phenomenon.

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High-Efficiency Wavelet Compressive Fusion for Improving MEMS Array Performance

Sensors ◽

10.3390/s20061662 ◽

2020 ◽

Vol 20 (6) ◽

pp. 1662 ◽

Cited By ~ 2

Author(s):

Siyuan Liang ◽

Weilong Zhu ◽

Feng Zhao ◽

Congyi Wang

Keyword(s):

Real Time ◽

High Efficiency ◽

Microelectromechanical Systems ◽

Inertial Sensor ◽

Low Cost ◽

Rapid Development ◽

Experimental Results ◽

Zero Bias ◽

Real Time Processing ◽

Application Range

With the rapid development of microelectromechanical systems (MEMS) technology, low-cost MEMS inertial devices have been widely used for inertial navigation. However, their application range is greatly limited in some fields with high precision requirements because of their low precision and high noise. In this paper, to improve the performance of MEMS inertial devices, we propose a highly efficient optimal estimation algorithm for MEMS arrays based on wavelet compressive fusion (WCF). First, the algorithm uses the compression property of the multiscale wavelet transform to compress the original signal, fusing the compressive data based on the support. Second, threshold processing is performed on the fused wavelet coefficients. The simulation result demonstrates that the proposed algorithm performs well on the output of the inertial sensor array. Then, a ten-gyro array system is designed for collecting practical data, and the frequency of the embedded processor in our verification environment is 800 MHz. The experimental results show that, under the normal working conditions of the MEMS array system, the 100 ms input array data require an approximately 75 ms processing delay when employing the WCF algorithm to support real-time processing. Additionally, the zero-bias instability, angle random walk, and rate slope of the gyroscope are improved by 8.0, 8.0, and 9.5 dB, respectively, as compared with the original device. The experimental results demonstrate that the WCF algorithm has outstanding real-time performance and can effectively improve the accuracy of low-cost MEMS inertial devices.

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Janus – A New Approach to Air Combat Pilot Training

Transactions on Aerospace Research ◽

10.2478/tar-2019-0019 ◽

2019 ◽

Vol 2019 (4) ◽

pp. 7-22

Author(s):

Georges Bridel ◽

Zdobyslaw Goraj ◽

Lukasz Kiszkowiak ◽

Jean-Georges Brévot ◽

Jean-Pierre Devaux ◽

...

Keyword(s):

Low Cost ◽

Cost Effective ◽

High Energy ◽

Training System ◽

Embedded Sensors ◽

Pilot Training ◽

New Approach ◽

Combat Aircraft ◽

Air Combat ◽

The Cost

Abstract Advanced jet training still relies on old concepts and solutions that are no longer efficient when considering the current and forthcoming changes in air combat. The cost of those old solutions to develop and maintain combat pilot skills are important, adding even more constraints to the training limitations. The requirement of having a trainer aircraft able to perform also light combat aircraft operational mission is adding unnecessary complexity and cost without any real operational advantages to air combat mission training. Thanks to emerging technologies, the JANUS project will study the feasibility of a brand-new concept of agile manoeuvrable training aircraft and an integrated training system, able to provide a live, virtual and constructive environment. The JANUS concept is based on a lightweight, low-cost, high energy aircraft associated to a ground based Integrated Training System providing simulated and emulated signals, simulated and real opponents, combined with real-time feedback on pilot’s physiological characteristics: traditionally embedded sensors are replaced with emulated signals, simulated opponents are proposed to the pilot, enabling out of sight engagement. JANUS is also providing new cost effective and more realistic solutions for “Red air aircraft” missions, organised in so-called “Aggressor Squadrons”.

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Treatment of wastewater by constructed wetland in small settlements

Water Science & Technology ◽

10.2166/wst.2000.0012 ◽

2000 ◽

Vol 41 (1) ◽

pp. 69-72 ◽

Cited By ~ 13

Author(s):

S.Ç. Ayaz ◽

I. Akca

Keyword(s):

Environmental Pollution ◽

Constructed Wetland ◽

Pilot Plant ◽

Low Cost ◽

Experimental System ◽

Suspended Solid ◽

Loading Conditions ◽

Treatment Performance ◽

Per Capita ◽

One Year

The constructed wetland is a low-cost technology to control environmental pollution. The system is especially suitable for small settlements. An innovative constructed wetland technology is described in this paper. A pilot plant was used to assess the performance of the system. The experimental system consists of two serial connected tanks that settled up with fillers and Cyperus as treatment media. Wastewater is recycled periodically upward and downward between the two tanks. The treatment performance was monitored in different loading conditions in a one-year period. The average COD removal efficiency of 90% was observed at 122 g COD/m2.day average loading conditions. Other average removal values in the same conditions are as follows: suspended solid 95%, TKN 77%, total nitrogen 61%, PO4-P 39%. The land requirement for this system will be 0.82 m2 per capita when applying as full-scale system.

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High-Energy-Density, Long-Life Lithium–Sulfur Batteries with Practically Necessary Parameters Enabled by Low-Cost Fe–Ni Nanoalloy Catalysts

ACS Nano ◽

10.1021/acsnano.1c00446 ◽

2021 ◽

Author(s):

Jiarui He ◽

Amruth Bhargav ◽

Arumugam Manthiram

Keyword(s):

Energy Density ◽

Low Cost ◽

High Energy ◽

High Energy Density ◽

Lithium Sulfur Batteries ◽

Long Life ◽

Lithium Sulfur

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Na0.76V6O15/Activated Carbon Hybrid Cathode for High-Performance Lithium-Ion Capacitors

Materials ◽

10.3390/ma14010122 ◽

2020 ◽

Vol 14 (1) ◽

pp. 122

Author(s):

Renwei Lu ◽

Xiaolong Ren ◽

Chong Wang ◽

Changzhen Zhan ◽

Ding Nan ◽

...

Keyword(s):

Activated Carbon ◽

Energy Density ◽

Power Density ◽

Cathode Materials ◽

Low Cost ◽

Lithium Ion ◽

High Energy ◽

Cycling Stability ◽

High Energy Density ◽

Artificial Graphite

Lithium-ion hybrid capacitors (LICs) are regarded as one of the most promising next generation energy storage devices. Commercial activated carbon materials with low cost and excellent cycling stability are widely used as cathode materials for LICs, however, their low energy density remains a significant challenge for the practical applications of LICs. Herein, Na0.76V6O15 nanobelts (NaVO) were prepared and combined with commercial activated carbon YP50D to form hybrid cathode materials. Credit to the synergism of its capacitive effect and diffusion-controlled faradaic effect, NaVO/C hybrid cathode displays both superior cyclability and enhanced capacity. LICs were assembled with the as-prepared NaVO/C hybrid cathode and artificial graphite anode which was pre-lithiated. Furthermore, 10-NaVO/C//AG LIC delivers a high energy density of 118.9 Wh kg−1 at a power density of 220.6 W kg−1 and retains 43.7 Wh kg−1 even at a high power density of 21,793.0 W kg−1. The LIC can also maintain long-term cycling stability with capacitance retention of approximately 70% after 5000 cycles at 1 A g−1. Accordingly, hybrid cathodes composed of commercial activated carbon and a small amount of high energy battery-type materials are expected to be a candidate for low-cost advanced LICs with both high energy density and power density.

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Optically transparent and very thin structure against electromagnetic pulse (EMP) using metal mesh and saltwater for shielding windows

Scientific Reports ◽

10.1038/s41598-021-80969-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Duy Tung Phan ◽

Chang Won Jung

Keyword(s):

Electromagnetic Pulse ◽

Low Cost ◽

High Energy ◽

Metal Plate ◽

Optical Transparency ◽

Shielding Effectiveness ◽

Concrete Wall ◽

Metal Mesh ◽

Wide Range ◽

Optically Transparent

AbstractAn electromagnetic pulse (EMP) with high energy can damage electronic equipment instantly within a wide range of thousands of kilometers. Generally, a metal plate placed inside a thick concrete wall is used against an EMP, but it is not suitable for an EMP shielding window, which requires not only strong shielding effectiveness (SE) but also optical transparency (OT). In this paper, we propose a very thin and optically transparent structure with excellent SE for EMP shielding window application. The proposed structure consists of a saltwater layer held between two glass substrates and two metal mesh layers on the outside of the glass, with a total thickness of less than 1.5 cm. The SE and OT of the structure are above 80 dB and 45%, respectively, which not only meet the requirement of EMP shielding for military purposes but also retain the procedure of good observation. Moreover, the OT of the structure can be significantly improved using only one metal mesh film (MMF) layer, while the SE is still maintained high to satisfy the required SE for home applicants. With the major advantages of low cost, optical transparency, strong SE, and flexible performance, the proposed structure can be considered a good solution for transparent EMP shielding windows.

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A 40 Mb/s VLC System Reusing an Existing Large LED Panel in an Indoor Office Environment

Sensors ◽

10.3390/s21051697 ◽

2021 ◽

Vol 21 (5) ◽

pp. 1697

Author(s):

Xicong Li ◽

Zabih Ghassemlooy ◽

Stanislav Zvánovec ◽

Paul Anthony Haigh

Keyword(s):

Modulation Depth ◽

Light Emitting Diode ◽

Low Cost ◽

Data Communication ◽

Experimental System ◽

Digital Signal ◽

Visible Light Communication ◽

Cost Driver ◽

Limiting Factors ◽

Light Sources

With advances in solid-state lighting, visible light communication (VLC) has emerged as a promising technology to enhance existing light-emitting diode (LED)-based lighting infrastructure by adding data communication capabilities to the illumination functionality. The last decade has witnessed the evolution of the VLC concept through global standardisation and product launches. Deploying VLC systems typically requires replacing existing light sources with new luminaires that are equipped with data communication functionality. To save the investment, it is clearly desirable to make the most of the existing illumination systems. This paper investigates the feasibility of adding data communication functionality to the existing lighting infrastructure. We do this by designing an experimental system in an indoor environment based on an off-the-shelf LED panel typically used in office environments, with the dimensions of 60 × 60 cm2. With minor modifications, the VLC function is implemented, and all of the modules of the LED panel are fully reused. A data rate of 40 Mb/s is supported at a distance of up to 2 m while using the multi-band carrierless amplitude and phase (CAP) modulation. Two main limiting factors for achieving higher data rates are observed. The first factor is the limited bandwidth of the LED string inside the panel. The second is the flicker due to the residual ripple of the bias current that is generated by the panel’s driver. Flicker is introduced by the low-cost driver, which provides bias currents that fluctuate in the low frequency range (less than several kilohertz). This significantly reduces the transmitter’s modulation depth. Concurrently, the driver can also introduce an effect that is similar to baseline wander at the receiver if the flicker is not completely filtered out. We also proposed a solution based on digital signal processing (DSP) to mitigate the flicker issue at the receiver side and its effectiveness has been confirmed.

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IoT Platform for Energy Sustainability in University Campuses

Sensors ◽

10.3390/s21020357 ◽

2021 ◽

Vol 21 (2) ◽

pp. 357

Author(s):

Pedro Moura ◽

José Ignacio Moreno ◽

Gregorio López López ◽

Manuel Alvarez-Campana

Keyword(s):

Energy Demand ◽

New Technologies ◽

Low Cost ◽

Sustainable Use ◽

High Energy ◽

Appropriate Technology ◽

Monitoring And Control ◽

Energy Sustainability ◽

University Campuses ◽

Iot Platform

University campuses are normally constituted of large buildings responsible for high energy demand, and are also important as demonstration sites for new technologies and systems. This paper presents the results of achieving energy sustainability in a testbed composed of a set of four buildings that constitute the Telecommunications Engineering School of the Universidad Politécnica de Madrid. In the paper, after characterizing the consumption of university buildings for a complete year, different options to achieve more sustainable use of energy are presented, considering the integration of renewable generation sources, namely photovoltaic generation, and monitoring and controlling electricity demand. To ensure the implementation of the desired monitoring and control, an internet of things (IoT) platform based on wireless sensor network (WSN) infrastructure was designed and installed. Such a platform supports a smart system to control the heating, ventilation, and air conditioning (HVAC) and lighting systems in buildings. Furthermore, the paper presents the developed IoT-based platform, as well as the implemented services. As a result, the paper illustrates how providing old existing buildings with the appropriate technology can contribute to the objective of transforming such buildings into nearly zero-energy buildings (nZEB) at a low cost.

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A High-Performance Free-Standing Zn Anode for Flexible Zinc-Ion Batteries

Nanoscale ◽

10.1039/d1nr01266e ◽

2021 ◽

Author(s):

Chenxi Gao ◽

Jiawei Wang ◽

Yuan Huang ◽

Zixuan Li ◽

Jiyan Zhang ◽

...

Keyword(s):

Energy Density ◽

High Performance ◽

Low Cost ◽

High Energy ◽

Zinc Ion ◽

High Energy Density ◽

Free Standing ◽

Energy Device ◽

Zn Anode ◽

Significant Attention

Zinc-ion batteries (ZIBs) have attracted significant attention owing to their high safety, high energy density, and low cost. ZIBs have been studied as a potential energy device for portable and...

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