scholarly journals Electrical and Magnetodielectric Properties of Magneto-Active Fabrics for Electromagnetic Shielding and Health Monitoring

2020 ◽  
Vol 21 (13) ◽  
pp. 4785
Author(s):  
Madalin Bunoiu ◽  
Eugen Mircea Anitas ◽  
Gabriel Pascu ◽  
Larisa Marina Elisabeth Chirigiu ◽  
Ioan Bica
Keyword(s):  
Electrical Properties ◽  
Electric Fields ◽  
Health Monitoring ◽  
Silicone Oil ◽  
Low Cost ◽  
Relaxation Times ◽  
Dielectric Materials ◽  
Medium Frequency ◽  
Mass Fractions ◽  
Electromagnetic Pollution

An efficient, low-cost and environmental-friendly method to fabricate magneto-active fabrics (MAFs) based on cotton fibers soaked with silicone oil and iron oxide microfibers (mFe) at mass fractions 2 wt.%, 4 wt.% and 8 wt.% is presented. It is shown that mFe induce good magnetic properties in MAFs, which are subsequently used as dielectric materials for capacitor fabrication. The electrical properties of MAFs are investigated in a static magnetic field with intensities of 0 kA/m, 160 kA/m and 320 kA/m, superimposed on a medium-frequency electric field. The influence of mFe on the electrical capacitance and dielectric loss tangent is determined, and it can be observed that the electrical conductivity, dielectric relaxation times and magnetodielectric effects are sensibly influenced by the applied magnetic and electric fields. The results indicate that the MAFs have electrical properties which could be useful for protection against electromagnetic pollution or for health monitoring.

scholarly journals Graphene Platelets-Based Magnetoactive Materials with Tunable Magnetoelectric and Magnetodielectric Properties

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1783
Author(s):  
Ioan Bica ◽  
Eugen Mircea Anitas
Keyword(s):  
Magnetic Field ◽  
Silicone Oil ◽  
Dielectric Materials ◽  
Cotton Fibers ◽  
Magnetic Flux Density ◽  
Electrical Capacitance ◽  
Medium Frequency ◽  
Physical Mechanisms ◽  
Electrical Devices ◽  
Living Organisms

We fabricate hybrid magnetoactive materials (hMAMs) based on cotton fibers, silicone oil, carbonyl iron and graphene nanoplatelets (nGr) at various mass concentrations ΦnGr. The obtained materials are used as dielectric materials for manufacturing plane electrical capacitors. The equivalent electrical capacitance Cp and resistance Rp are measured in an electric field of medium frequency f, without and respectively with a magnetic field of magnetic flux density B in the range from 0.1 T up to 0.5 T. The results are used to extract the components ϵr′ and ϵr″ of the complex relative permittivity ϵr*, and to reveal the magnitude of the induced magnetoelectric couplings kx and magnetodielectric effects MDE. It is shown that ϵr′, ϵr″, kx and MDE are significantly influenced by f,B and ΦnGr. We describe the underlying physical mechanisms in the framework of dipolar approximation and using elements of dielectric theory. The tunable magnetoelectric and magnetodielectric properties of hMAMs are useful for manufacturing electrical devices for electromagnetic shielding of living organisms.

scholarly journals Hybrid Magnetorheological Composites for Electric and Magnetic Field Sensors and Transducers

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 2060
Author(s):  
Ioan Bica ◽  
Eugen Mircea Anitas ◽  
Liviu Chirigiu
Keyword(s):  
Magnetic Field ◽  
Silicone Oil ◽  
Low Cost ◽  
Relative Dielectric Constant ◽  
Dielectric Materials ◽  
Electrical Capacitance ◽  
Magnetic Dipoles ◽  
Magnetic Field Sensors ◽  
Electrical Devices ◽  
Recorded Data

We present a simple, low-cost, and environmental-friendly method for the fabrication of hybrid magnetorheological composites (hMCs) based on cotton fibers soaked with a mixture of silicone oil (SO), carbonyl iron (CI) microparticles, and iron oxide microfibers (μF). The obtained hMCs, with various ratios (Φ) of SO and μF, are used as dielectric materials for manufacturing electrical devices. The equivalent electrical capacitance and resistance are investigated in the presence of an external magnetic field, with flux density B. Based on the recorded data, we obtain the variation of the relative dielectric constant (ϵr′), and electrical conductivity (σ), with Φ, and B. We show that, by increasing Φ, the distance between CI magnetic dipoles increases, and this leads to significant changes in the behaviour of ϵr′ and σ in a magnetic field. The results are explained by developing a theoretical model that is based on the dipolar approximation. They indicate that the obtained hMCs can be used in the fabrication of magneto-active fibers for fabrication of electric/magnetic field sensors and transducers.

Surface confinement induces the formation of solid-like insulating ionic liquid nanostructures

2017 ◽  
Author(s):  
Massimiliano Galluzzi ◽  
Simone Bovio ◽  
Paolo Milani ◽  
Alessandro Podestà
Keyword(s):  
Ionic Liquid ◽  
Electrical Properties ◽  
Electric Fields ◽  
Relative Dielectric Constant ◽  
Ionic Mobility ◽  
Electric Properties ◽  
Bulk Liquid ◽  
Structural Reorganization ◽  
Surface Confinement ◽  
Insulator Layers

We report on the modification of the electric properties of the imidazolium-based [BMIM][NTf2] ionic liquid upon surface confinement in the sub-monolayer regime. Solid-like insulating nanostructures of [BMIM][NTf2] spontaneously form on a variety of insulating substrates, at odd with the liquid and conductive nature of the same substances in the bulk phase. A systematic spatially resolved investigation by atomic force microscopy of the morphological, mechanical and electrical properties of [BMIM][NTf2] nanostructures showed that this liquid substance rearranges into lamellar nanostructures with a high degree of vertical order and enhanced resistance to mechanical compressive stresses and very intense electric fields, denoting a solid-like character. The morphological and structural reorganization has a profound impact on the electric properties of supported [BMIM][NTf2] islands, which behave like insulator layers with a relative dielectric constant between 3 and 5, comparable to those of conventional ionic solids, and significantly smaller than those measured in the bulk ionic liquid. These results suggest that in the solid-like ordered domains confined either at surfaces or inside the pores of the nanoporous electrodes of photo-electrochemical devices, the ionic mobility and the overall electrical properties can be significantly perturbed with respect to the bulk liquid phase, which would likely influence the<br>performance of the devices.<br>

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.

Electrical Properties of Flames. BurnerFlames in Longitudinal Electric Fields.

1951 ◽  
Vol 43 (12) ◽  
pp. 2726-2731 ◽  
Author(s):  
Hartwell F. Calcote ◽  
Robert N. Pease
Keyword(s):  
Electrical Properties ◽  
Electric Fields

scholarly journals Advances in the Structural Health Monitoring of Bridges Using Piezoelectric Transducers

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4312 ◽  
Author(s):  
Yunzhu Chen ◽  
Xingwei Xue
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Piezoelectric Materials ◽  
Low Cost ◽  
Rapid Development ◽  
Concrete Strength ◽  
Steel Corrosion ◽  
Fast Response ◽  
Future Application ◽  
Structural Health

With the rapid development of the world’s transportation infrastructure, many long-span bridges were constructed in recent years, especially in China. However, these bridges are easily subjected to various damages due to dynamic loads (such as wind-, earthquake-, and vehicle-induced vibration) or environmental factors (such as corrosion). Therefore, structural health monitoring (SHM) is vital to guarantee the safety of bridges in their service lives. With its wide frequency response range, fast response, simple preparation process, ease of processing, low cost, and other advantages, the piezoelectric transducer is commonly employed for the SHM of bridges. This paper summarizes the application of piezoelectric materials for the SHM of bridges, including the monitoring of the concrete strength, bolt looseness, steel corrosion, and grouting density. For each problem, the application of piezoelectric materials in different research methods is described. The related data processing methods for four types of bridge detection are briefly summarized, and the principles of each method in practical application are listed. Finally, issues to be studied when using piezoelectric materials for monitoring are discussed, and future application prospects and development directions are presented.

Initial Results On Medium Frequency Electromagnetic Field Penetration In Biological Soft Tissue

2012 ◽  
Author(s):  
Zulkarnay Zakaria ◽  
Mohd Fahajumi Jumaah ◽  
Mohd Saiful Badri Mansor ◽  
Khairi Mat Daud ◽  
Mohd Hafiz Fazalul Rahiman ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Soft Tissue ◽  
Soft Tissues ◽  
Low Cost ◽  
The Body ◽  
Small Scale ◽  
Medium Frequency ◽  
Magnetic Field Penetration ◽  
Magnetic Induction Tomography ◽  
Field Penetration

Terapi merupakan antara teknik perubatan tertua dalam mengekalkan kesihatan badan terutama daripada aliran darah yang tidak baik, strok dan beberapa penyakit yang lain. Teknik ini termasuklah akupuntur, guasa dan juga urutan. Terdapat juga teknik terapi moden seperti terapi warna, terapi ozon, terapi dadah dan banyak lagi. Kertas kajian ini akan mengetengahkan penjana terapi elektromagnet, satu alat yang mempunyai potensi aplikasi terapi dalam bidang perubatan. Alat ini menghasilkan medan magnet berfrekuensi sederhana sebagai sumber terapi. Perkakasan yang berskala kecil berfrekuensi sederhana dan berkos rendah ini telah dibangunkan dan telah diuji pada tisu biologi bagi mengukur tahap ketembusan medan magnet. Ujian ini telah membuktikan bahawa medan magnet yang telah dihasilkan mampu menembusi tisu lembut bersaiz sehingga 2 cm dengan jarak 7 cm daripada sumber. Kebolehan penembusan sistem ini terhadap tisu lembut memberikan peluang yang cerah kepada kajian ini memandangkan medan magnet telah menunjukkan potensi sebagai sebahagian daripada terapi untuk memulihkan migraine, strok, kekejangan dan beberapa yang lain selain boleh diaplikasikan dalam pengimejan tomografi induksi magnet. Kata kunci: Terapi elektromagnet, medan magnet, penembusan, tisu lembut, aplikasi perubatan Therapy is among the oldest medication technique in maintaining the health of the body especially from bad blood circulation, stroke and several others. This technique includes acupuncture, guasa and also massage. There are also modern therapy techniques like colour therapy, water therapy, ozone therapy, drug therapy and others. This paper will highlight electromagnetic therapy generator, a device which has the potential of therapy application in medical field. This device produce medium frequency magnetic field as a therapy source. This small scale medium frequency and low cost hardware that has been developed was tested on the biological tissue for the purpose of measuring the magnetic field penetration. The testing has proven that the generated magnetic field is able to penetrate the soft tissue up to 2 cm with distance from the source up to 7 cm. The capability of the system penetrations through the soft tissues provide the bright future of this research since magnetic field have shown the potential as being part of the therapy for curing migraine, stroke, cramp and several others besides the application in the magnetic induction tomography imaging. Key words: Electromagnetic therapy, magnetic field, penetration, soft tissue; medical applications

scholarly journals Micropipette-Based Microfluidic Device for Monodisperse Microbubbles Generation

Micromachines ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 387
Author(s):  
Carlos Toshiyuki Matsumi ◽  
Wilson José da Silva ◽  
Fábio Kurt Schneider ◽  
Joaquim Miguel Maia ◽  
Rigoberto E. M. Morales ◽  
...  
Keyword(s):  
Electric Fields ◽  
Microfluidic Device ◽  
Soft Lithography ◽  
Low Cost ◽  
Characteristic Curve ◽  
Microfluidic Devices ◽  
Average Diameter ◽  
Internal Diameter ◽  
Medical Diagnostic ◽  
Average Size

Microbubbles have various applications including their use as carrier agents for localized delivery of genes and drugs and in medical diagnostic imagery. Various techniques are used for the production of monodisperse microbubbles including the Gyratory, the coaxial electro-hydrodynamic atomization (CEHDA), the sonication methods, and the use of microfluidic devices. Some of these techniques require safety procedures during the application of intense electric fields (e.g., CEHDA) or soft lithography equipment for the production of microfluidic devices. This study presents a hybrid manufacturing process using micropipettes and 3D printing for the construction of a T-Junction microfluidic device resulting in simple and low cost generation of monodisperse microbubbles. In this work, microbubbles with an average size of 16.6 to 57.7 μm and a polydispersity index (PDI) between 0.47% and 1.06% were generated. When the device is used at higher bubble production rate, the average diameter was 42.8 μm with increased PDI of 3.13%. In addition, a second-order polynomial characteristic curve useful to estimate micropipette internal diameter necessary to generate a desired microbubble size is presented and a linear relationship between the ratio of gaseous and liquid phases flows and the ratio of microbubble and micropipette diameters (i.e., Qg/Ql and Db/Dp) was found.

scholarly journals THE EFFECT OF POLYANILINE CONTENT DEPOSITED ON SILICA GEL PARTICLES ON THE ELECTRORHEOLOGY OF SILICONE-OIL SUSPENSIONS

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1097-1103 ◽  
Author(s):  
V. PAVLÍNEK ◽  
P. SÁHA ◽  
T. KITANO ◽  
J. HROMÁDKOVÁ ◽  
J. STEJSKAL ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Silicone Oil ◽  
Relaxation Times ◽  
Content Volume ◽  
Interfacial Polarization ◽  
Secondary Importance ◽  
Frequency Spectra ◽  
Pure Silica ◽  
A Value ◽  
Dc Electric Field

Investigation of the electrorheological effect of silicone-oil suspensions of silica particles coated with polyaniline base in a DC electric field revealed that breaking stress, as a criterion the intensity of the electrorheological phenomenon, steeply increased at first with coating thickness. At relatively low polyaniline content (volume fraction ≈ 0.05), it has reached a value several times higher than that with suspension of pure silica. Then they became virtually constant or slightly increased. The frequency spectra of dielectric characteristics of these systems reflect high relaxation times. The results suggest that the interfacial polarization of particles is predominantly controlled by polarizability of their surface layer, and the influence of the thickness is of secondary importance.

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