scholarly journals A Review on Synthesis and Characterizations of Mixed Nickel-Zinc Ferrites

2021 ◽  
pp. 189-217
Author(s):  
A. Kaur
Keyword(s):  
Electromagnetic Interference ◽  
Eddy Currents ◽  
Medical Science ◽  
Low Frequency ◽  
Industrial Applications ◽  
Research Progress ◽  
Intelligent Transport System ◽  
Semiconductor Memory ◽  
Nickel Zinc ◽  
Communication Devices

Nanotechnology, when this word comes in mind, it gives deep thought of new development in communication, medical science, intelligent transport system and many more. Ferrites nanoparticles have great significance owing to their amazing chemical and physical properties. In modern era we are developing materials for microwave applications and communication devices. Before the discovery of semiconductor memory chips, ferrites were the major form for electronic memory used in computers. Scientist have been studying and working with nanoparticles in magnetically guided drug delivery. The reactivity of material increases by the use of nanoparticles of that material. The dielectric characteristics of ferrites lean on diverse factors for instance methods of preparations and chemical composition. In various studies it has been found that their conductivity has dependence on temperature, composition and frequency. Among the various kinds of ferrites, Ni–Zn ferrites are viewed as the most adaptable ferrites as a result of their novel characteristics for applications at high frequency. The Ni-Zn ferrites are exploited as core materials in a variety of EM devices as well as have broad range of industrial applications e.g. inductors, microwave devices, power supplies, high and low frequency transformer cores, electromagnetic interference (EMI) suppressions and antenna rods. These broad ranges of applications are owing to their high resistivity, low eddy currents, high saturation magnetization, chemical stability and high Curie temperature. In view of this, the present chapter deals with the research progress on nickel-zinc ferrites in the bulk as well as nano size.

scholarly journals Switching Power Suppliers Noise Reduction in Ultrasound Doppler Fluid Measurements

Electronics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 421 ◽  
Author(s):  
Stefano Ricci
Keyword(s):  
Spread Spectrum ◽  
Electromagnetic Interference ◽  
Low Frequency ◽  
Industrial Applications ◽  
Doppler Spectrum ◽  
Switching Noise ◽  
Frequency Range ◽  
Ultrasound Doppler ◽  
Front End ◽  
Spread Spectrum Modulation

Ultrasound Doppler techniques are widely employed in detecting the velocity of moving fluids both in medical and industrial applications. Echo Doppler electronics systems include a highly sensitive front-end suitable to processing the very low power ultrasound echoes received by the transducer. Moreover, the front-end input bandwidth typically ranges between 100 kHz and 10 MHz, which is the same frequency range where modern switching regulators work. Thus, the front-end is particularly prone to the noise produced by the suppliers that power the board itself. Electromagnetic interference (EMI) filters and spread-spectrum modulation of the switching regulator frequency help, but the results are often not optimal, and unacceptable artifacts are visible in the Doppler spectrum. In this paper a spread-spectrum modulation is proposed that concentrates the switching noise in the low-frequency range of the Doppler spectrum (e.g., 0–100 Hz). This range is removed by the high-pass clutter filter normally used in velocity Doppler investigations, thus switching noise and artifacts are eliminated. The method is verified through mathematical simulations and tested in measurements carried out with a research Doppler system. An example is presented in which the artifacts present during the investigation of a 0.4-m/s flow in a 25.4-mm diameter pipe are effectively removed by the proposed method.

scholarly journals Pendulum-Type Hetero-Core Fiber Optic Accelerometer for Low-Frequency Vibration Monitoring

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2528 ◽  
Author(s):  
Hiroshi Yamazaki ◽  
Ichiro Kurose ◽  
Michiko Nishiyama ◽  
Kazuhiro Watanabe
Keyword(s):  
Fiber Optics ◽  
Electromagnetic Interference ◽  
Large Scale ◽  
Fiber Optic ◽  
Low Frequency ◽  
Fiber Optic Sensor ◽  
Vibration Monitoring ◽  
Vibration Measurement ◽  
Displacement Sensor ◽  
Core Fiber

In this paper, a novel pendulum-type accelerometer based on hetero-core fiber optics has been proposed for structural health monitoring targeting large-scale civil infrastructures. Vibration measurement is a non-destructive method for diagnosing the failure of structures by assessing natural frequencies and other vibration patterns. The hetero-core fiber optic sensor utilized in the proposed accelerometer can serve as a displacement sensor with robustness to temperature changes, in addition to immunity to electromagnetic interference and chemical corrosions. Thus, the hetero-core sensor inside the accelerometer measures applied acceleration by detecting the rotation of an internal pendulum. A series of experiments showed that the hetero-core fiber sensor linearly responded to the rotation angle of the pendulum ranging within (−6°, 4°), and furthermore the proposed accelerometer could reproduce the waveform of input vibration in a frequency band of several Hz order.

scholarly journals Evaluating Electromagnetic Interference of Communication Devices with Root ZX Mini Apex Locator

2016 ◽  
Vol 7 (4) ◽  
pp. 142
Author(s):  
Foad Iranmanesh ◽  
Marzieh Shafieibavani ◽  
Pedram Iranmanesh
Keyword(s):  
Electromagnetic Interference ◽  
Communication Devices

scholarly journals The Hybrid FEM-DBCI for the Solution of Open-Boundary Low-Frequency Problems

Mathematics ◽  
2021 ◽  
Vol 9 (16) ◽  
pp. 1968
Author(s):  
Giovanni Aiello ◽  
Salvatore Alfonzetti ◽  
Santi Agatino Rizzo ◽  
Nunzio Salerno
Keyword(s):  
Integral Equation ◽  
Eddy Currents ◽  
Computing Time ◽  
Low Frequency ◽  
Dirichlet Condition ◽  
Open Boundary ◽  
Coordinate Transformations ◽  
External Layer ◽  
Electromagnetic Problems ◽  
Electrostatic Fields

This paper describes a particular use of the hybrid FEM-DBCI, for the computation of low-frequency electromagnetic fields in open-boundary domains. Once the unbounded free space enclosing the system has been truncated, the FEM is applied to the bounded domain thus obtained, assuming an unknown Dirichlet condition on the truncation boundary. An integral equation is used to express this boundary condition in which the integration surface is selected in the middle of the most external layer of finite elements, very close to the truncation boundary, so that the integral equation becomes quasi-singular. The method is described for the computation of electrostatic fields in 3D and of eddy currents in 2D, but it is also applicable to the solution of other kinds of electromagnetic problems. Comparisons are made with other methods, concluding that FEM-DBCI is competitive with the well-known FEM-BEM and coordinate transformations for what concerns accuracy and computing time.

scholarly journals Research progress of small low-frequency transmitting antenna

2020 ◽  
Vol 69 (20) ◽  
pp. 208401
Author(s):  
Yong Cui ◽  
Ming Wu ◽  
Xiao Song ◽  
Yu-Ping Huang ◽  
Qi Jia ◽  
...  
Keyword(s):  
Low Frequency ◽  
Research Progress ◽  
Transmitting Antenna

scholarly journals Alternating (AC) Loop Current Attacks Against the KLJN Secure Key Exchange Scheme

2021 ◽  
pp. 2150050
Author(s):  
Mutaz Y. Melhem ◽  
Christiana Chamon ◽  
Shahriar Ferdous ◽  
Laszlo B. Kish
Keyword(s):  
Electromagnetic Interference ◽  
High Frequency ◽  
Practical Importance ◽  
Low Frequency ◽  
Key Exchange ◽  
Power Density Spectrum ◽  
Voltage Source ◽  
Loop Current ◽  
Johnson Noise ◽  
Density Spectrum

Recently, several passive and active attack methods have been proposed against the Kirchhoff–Law–Johnson–Noise (KLJN) secure key exchange scheme by utilizing direct (DC) loop currents. The DC current attacks are relatively easy, but their practical importance is low. On the other hand, parasitic alternating (AC) currents are virtually omnipresent in wire-based systems. Such situations exist due to AC ground loops and electromagnetic interference (EMI). However, utilizing AC currents for attacks is a harder problem. Here, we introduce and demonstrate AC current attacks in various frequency ranges. The attacks exploit a parasitic/periodic AC voltage-source at either Alice’s or Bob’s end. In the low-frequency case, the procedure is the generalized form of the former DC ground-loop-based attack. In the high-frequency case, the power density spectrum of the wire voltage is utilized. The attack is demonstrated in both the low and the high-frequency situations. Defense protocols against the attack are also discussed.

Impact of Wi-Fi Electromagnetic Waves on Brainwaves

2014 ◽  
Vol 1079-1080 ◽  
pp. 882-886 ◽  
Author(s):  
Fu Chien Kao ◽  
Shin Ping R. Wang ◽  
Yun Kai Lin ◽  
Chih Chia Chen ◽  
Chih Hsun Huang
Keyword(s):  
Wireless Communication ◽  
Communication Technology ◽  
Cognitive Neuroscience ◽  
Electromagnetic Waves ◽  
Medical Science ◽  
Low Frequency ◽  
Primary Study ◽  
Human Beings ◽  
Wireless Internet ◽  
Financial Transactions

In the era of wireless communication, WiFi becomes an indispensable accessory to most of us. People use WIFI to interact with the wireless Internet, perform commercial and financial transactions, or conducting recreational activities, etc.Though it offers a more convenient life to people, the strong Electromagnetic waves(EMW) resulted from it endangers human health, that has already turned out to be the primary study for medical science. Furthermore, EMW also attracts concern and panic of the inhabitants living in the surroundings which is filled with high-frequency and low-frequency EMwave. EMW today comes from broadcast towers, the system of the wireless communication, GPS, TVs and defense satellites mostly. Enjoying the convenience resulted from communication technology, people nowadays should also concern about whether EM wave would damage people’s health at the same time. Based on the perspective of cognitive neuroscience, this study mainly focuses on how EM wave produced from WiFi affects subject’s brainwaves under a specific physiological situation. The researcher observes different changing of brainwave when human beings expose in various strength of EM wave, and analyses the affection of EMW toward subject’s brainwaves.

scholarly journals Plate-Type Acoustic Metamaterials: Experimental Evaluation of a Modular Large-Scale Design for Low-Frequency Noise Control

Acoustics ◽  
2019 ◽  
Vol 1 (2) ◽  
pp. 354-368 ◽  
Author(s):  
Linus Ang ◽  
Yong Koh ◽  
Heow Lee
Keyword(s):  
Large Scale ◽  
Noise Control ◽  
Traffic Noise ◽  
Low Frequency ◽  
Industrial Applications ◽  
Frequency Noise ◽  
Acoustic Metamaterials ◽  
Scale Design ◽  
Stress Uniformity ◽  
Plate Type

For industrial applications, the scalability of a finalised design is an important factor to consider. The scaling process of typical membrane-type acoustic metamaterials may pose manufacturing challenges such as stress uniformity of the membrane and spatial consistency of the platelet. These challenges could be addressed by plate-type acoustic metamaterials with an internal tonraum resonator. By adopting the concept of modularity in a large-scale design (or meta-panel), the acoustical performance of different specimen configurations could be scaled and modularly combined. This study justifies the viability of two meta-panel configurations for low-frequency (80–500 Hz) noise control. The meta-panels were shown to be superior to two commercially available noise barriers at 80–500 Hz. This superiority was substantiated when the sound transmission class (STC) and the outdoor-indoor transmission class (OITC) were compared. The meta-panels were also shown to provide an average noise reduction of 22.7–27.4 dB at 80–400 Hz when evaluated in different noise environments—traffic noise, aircraft flyby noise, and construction noise. Consequently, the meta-panel may be further developed and optimised to obtain a design that is lightweight and yet has good acoustical performance at below 500 Hz, which is the frequency content of most problematic noises.

Research progress in materials-oriented chemical engineering in China

2019 ◽  
Vol 35 (8) ◽  
pp. 917-927 ◽  
Author(s):  
Hao Jiang ◽  
Yongsheng Han ◽  
Qiang Zhang ◽  
Jiexin Wang ◽  
Yiqun Fan ◽  
...  
Keyword(s):  
Chemical Engineering ◽  
Materials Science ◽  
Industrial Applications ◽  
Advanced Materials ◽  
Research Progress ◽  
Material Research ◽  
Engineering Science ◽  
New Materials ◽  
Engineering Development ◽  
Recent Advances

Abstract Materials-oriented chemical engineering involves the intersection of materials science and chemical engineering. Development of materials-oriented chemical engineering not only contributes to material research and industrialization techniques but also opens new avenues for chemical engineering science. This review details the major achievements of materials-oriented chemical engineering fields in China, including preparation strategies for advanced materials based on the principles of chemical engineering as well as innovative separation and reaction techniques determined by new materials. Representative industrial applications are also illustrated, highlighting recent advances in the field of materials-oriented chemical engineering technologies. In addition, we also look at the ongoing trends in materials-oriented chemical engineering in China.

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