The influence of the transparent layer thickness on the absorption capacity of epoxy/carbon nanotube buckypaper at X‐band

2021 ◽  
pp. 51407
Author(s):  
Felipe Carlos dos Reis ◽  
Mirabel Cerqueira Rezende ◽  
Bruno Ribeiro
Keyword(s):  
Carbon Nanotube ◽  
Layer Thickness ◽  
Absorption Capacity ◽  
Transparent Layer ◽  
X Band

The coating of composite nanoparticles of BaFe12O19/multi-walled carbon nanotubes using silicon matrix on nonwoven substrate for radar absorption in X and Ku bands

2017 ◽  
Vol 47 (8) ◽  
pp. 1867-1886 ◽  
Author(s):  
Arezoo Afzali ◽  
Vahid Mottaghitalab ◽  
Seyed Salman Afghahi ◽  
Mojtaba Jafarian
Keyword(s):  
Carbon Nanotube ◽  
Band Width ◽  
Composite Nanoparticles ◽  
Coated Sample ◽  
Maximum Absorption ◽  
Silicon Matrix ◽  
Multi Walled Carbon Nanotube ◽  
X Band ◽  
Fabric Surface ◽  
Ku Band

A novel radar absorbing material was developed on nonwoven fabric using BaFe12O19/multi-walled carbon nanotube, which was synthesized by combustive sol–gel technique. The functional carboxylated multi-walled carbon nanotube was utilized in silicon matrix and printed on fabric surface to enhance the intensity and band width of wave absorption. The crystalline structure, morphology, and magnetic properties were characterized by X-ray diffraction, field emission scanning electron microscope, and vibrating sample magnetometer. The maximum reflection loss of nanoparticles was measured about −7 dB on 9.5 GHz. Moreover, the maximum absorption in X band was close to −38.45 dB in 10.5 GHz at the thickness of 1.5 mm with bandwidth of 2.6 GHz. Moreover, in Ku band, the maximum absorption for BaFe12O19/multi-walled carbon nanotube sample with thickness of 1.5 mm was reported as −31.38 dB, which was recorded on 15.9 GHz with 3.2 GHz bandwidth. Interestingly, the fabric coated with bare BaFe12O19 nanoparticle exhibits a maximum absorption of −3.5 dB at 9.7 GHz, which is lower compared to the absorption value of −17.8 dB at 9.8 GHZ for the fabric coated with BaFe12O19/multi-walled carbon nanotube. However, in Ku band, the fabric coated with BaFe12O19 nanoparticles shows lower value of −2.4 dB compared to X band in 17.6 GHz. In comparison, for composite nanoparticles coated sample, a nearly similar maximum value of −17.6 dB was recorded on 16.7 GHz with band width of 2.2 GHz. Results indicate appreciable maximum absorption value of more than 90% in X and Ku band, which can be attributed to presence of carbon structure in composite material.

Transparent layer thickness measurement using low-coherence interference microscopy

2015 ◽  
Author(s):  
P. Kühnhold ◽  
A. Nolvi ◽  
S. Tereschenko ◽  
I. Kassamakov ◽  
E. Hæggström ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Thickness Measurement ◽  
Interference Microscopy ◽  
Low Coherence ◽  
Transparent Layer

Microwave absorption properties of magnetite multi-granule nanocluster–multiwall carbon nanotube composites

2019 ◽  
Vol 12 (02) ◽  
pp. 1950011
Author(s):  
Boo Hyun An ◽  
Bum Chul Park ◽  
Amarsingh Bhabu Kanagaraj ◽  
Prerna Chaturvedi ◽  
Hamad Al Yassi ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Tape Casting ◽  
Granule Size ◽  
Multiwall Carbon Nanotube ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
X Band ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites ◽  
Multiwall Carbon

Fe3O4 multi-granule nanocluster–multiwall carbon nanotube composites for microwave absorbing applications are fabricated by the surface-engineered tape-casting method. The multi-granule nanoclusters are synthesized by a modified polyol hydrothermal method and characterized by transmission electron microscopy, X-ray diffraction and vibrating sample magnetometer. The complex permittivity and permeability of the composites with different granule size of nanoclusters are characterized in X-band range with the reflection method. The absorption peak of the composites are shifted from 11.1[Formula: see text]GHz to 11.51[Formula: see text]GHz as granule size increased from 18[Formula: see text]nm to 35[Formula: see text]nm.

scholarly journals Effect of Loading and Functionalization of Carbon Nanotube on the Performance of Blended Polysulfone/Polyethersulfone Membrane during Treatment of Wastewater Containing Phenol and Benzene

Membranes ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 54 ◽  
Author(s):  
Mabusha S. Rameetse ◽  
Oluseyi Aberefa ◽  
Michael O. Daramola
Keyword(s):  
Thermal Stability ◽  
Carbon Nanotube ◽  
Mechanical Strength ◽  
Petroleum Industry ◽  
Absorption Capacity ◽  
Synthetic Wastewater ◽  
Separation Performance ◽  
Blended Polymer ◽  
And Performance ◽  
Pes Membrane

In this study, a carbon nanotube (CNT)-infused blended polymer membrane was prepared and evaluated for phenol and benzene removal from petroleum industry wastewater. A 25:75 (by weight %) blended polysulfone/polyethersulfone (PSF/PES) membrane infused with CNTs was prepared and tested. The effect of functionalization of the CNTs on the quality and performance of the membrane was also investigated. The membranes were loaded with CNTs at different loadings: 0.5 wt. %, 1 wt. %, 1.5 wt. % pure CNTs (pCNTs) and 1 wt. % functionalized CNTs (fCNTs), to gain an insight into the effect of the amount of CNT on the quality and performance of the membranes. Physicochemical properties of the as-prepared membranes were obtained using scanning electron microscopy (SEM) for morphology, Raman spectroscopy for purity of the CNTs, Fourier transform infrared (FTIR) for surface chemistry, thermogravimetric analysis (TGA) for thermal stability, atomic force microscopy (AFM) for surface nature and nano-tensile analysis for the mechanical strength of the membranes. The performance of the membrane was tested with synthetic wastewater containing 20 ppm of phenol and 20 ppm of benzene using a dead-end filtration cell at a pressure ranging from 100 to 300 kPa. The results show that embedding CNTs in the blended polymer (PSF/PES) increased both the porosity and water absorption capacity of the membranes, thereby resulting in enhanced water flux up to 309 L/m2h for 1.5 wt. % pCNTs and 326 L/m2h for 1 wt. % functionalized CNT-loaded membrane. Infusing the polysulfone/polyethersulfone (PSF/PES) membrane with CNTs enhanced the thermal stability and mechanical strength. Results from AFM indicate enhanced hydrophilicity of the membranes, translating in the enhancement of anti-fouling properties of the membranes. However, the % rejection of membranes with CNTs decreased with an increase in pCNTs concentration and pressure, while it increased the membrane with fCNTs. The % rejection of benzene in the pCNTs membrane decreased with 13.5% and 7.55% in fCNT membrane while phenol decreased with 55.6% in pCNT membrane and 42.9% in the FCNT membrane. This can be attributed to poor CNT dispersion resulting in increased pore sizes observed when CNT concentration increases. Optimization of membrane synthesis might be required to enhance the separation performance of the membranes.

scholarly journals Active-layer thickness estimation from X-band SAR backscatter intensity

2017 ◽  
Vol 11 (1) ◽  
pp. 483-496 ◽  
Author(s):  
Barbara Widhalm ◽  
Annett Bartsch ◽  
Marina Leibman ◽  
Artem Khomutov
Keyword(s):  
Layer Thickness ◽  
Active Layer ◽  
Satellite Data ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Active Layer Thickness ◽  
Backscatter Intensity ◽  
X Band ◽  
Spatial Coverage ◽  
Microwave Backscatter

Abstract. The active layer above the permafrost, which seasonally thaws during summer, is an important parameter for monitoring the state of permafrost. Its thickness is typically measured locally, but a range of methods which utilize information from satellite data exist. Mostly, the normalized difference vegetation index (NDVI) obtained from optical satellite data is used as a proxy. The applicability has been demonstrated mostly for shallow depths of active-layer thickness (ALT) below approximately 70 cm. Some permafrost areas including central Yamal are, however, characterized by larger ALT. Surface properties including vegetation structure are also represented by microwave backscatter intensity. So far, the potential of such data for estimating ALT has not been explored. We therefore investigated the relationship between ALT and X-band synthetic aperture radar (SAR) backscatter of TerraSAR-X (averages for 10  ×  10 m window) in order to examine the possibility of delineating ALT with continuous and larger spatial coverage in this area and compare it to the already-established method of using NDVI from Landsat (30 m). Our results show that the mutual dependency of ALT and TerraSAR-X backscatter on land cover types suggests a connection of both parameters. A range of 5 dB can be observed for an ALT range of 100 cm (40–140 cm), and an R2 of 0.66 has been determined over the calibration sites. An increase of ALT with increasing backscatter can be determined. The root mean square error (RMSE) over a comparably heterogeneous validation site with maximum ALT of  >  150 cm is 20 cm. Deviations are larger for measurement locations with mixed vegetation types (especially partial coverage by cryptogam crust) with respect to the spatial resolution of the satellite data.

The Effects of Layer Thickness of Radar Absorbing Materials Prepared by Double Layer Method on X-Band Wavelength Frequency

2019 ◽  
Vol 966 ◽  
pp. 35-40
Author(s):  
Mochamad Zainuri ◽  
Rahma Fitri Puspitasari ◽  
Deril Ristiani ◽  
Triwikantoro
Keyword(s):  
Layer Thickness ◽  
Double Layer ◽  
Reflection Loss ◽  
Dielectric Material ◽  
Soft Magnetic ◽  
Solid State Method ◽  
X Band ◽  
Thickness Variations ◽  
Polymerization Method ◽  
Layer Coating

Double layer coating with variations in layer thickness on radar absorbent material (RAM), and Polyaniline dobed by DBSA as a dielectric material has been successfully synthesized. As well as Barium M-Hexaferrite doped by Zn2+ at x=0.9 as magnetic material successfully synthesized. Polyaniline has been synthesized by polymerization method and Barium M-Hexaferrite has been synthesized by solid state method. Characterization results obtained the conductivity of Polyaniline and Barium M-Hexaferrite respectively 4.4 × 10-1 S/m and 2.09 × 10-3 S/m, both of which are in range of semiconductor materials conductivity. The presence of Zn2+ doping successfully reduced hard magnetic properties of Barium M-Hexaferrite to be soft magnetic, with coercivity field (Hc) equals 0.0181 Tesla. Based on research that has been done, represent that double layer design with variations PANi : PANi + BaM (3:1) has maximum reflection loss value about -29,6003 dB, and 96.69% of energy absorbed. Whereas in variation of PANi: PANi + BaM (3: 1) has minimum reflection loss value about -15.2937 dB, and 82.21% of energy absorbed. In addition, the coating thickness variations also affect the absorption band width, with the most effective absorption peaks in “D” variation with bandwidth equals 1.81 GHz in range of frequency 8 to 9.81 GHz.

scholarly journals Study on Lightweight and Strengthening Effect of Carbon Nanotube in Highly Ordered Nanoporous Nickel: A Molecular Dynamics Study

2019 ◽  
Vol 9 (2) ◽  
pp. 352 ◽  
Author(s):  
Yu Zhou ◽  
Wu-Gui Jiang ◽  
Duo-Sheng Li ◽  
Qing-Hua Qin
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Carbon Nanotube ◽  
Tensile Modulus ◽  
Md Simulations ◽  
Absorption Capacity ◽  
Atomic Scale ◽  
Strengthening Effect ◽  
Pore Collapse ◽  
Out Of Plane

The mechanical behavior of nanocomposites consisting of highly ordered nanoporous nickel (HONN) and its carbon nanotube (CNT)-reinforced composites (CNHONNs) subjected to a high temperature of 900 K is investigated via molecular dynamics (MD) simulations. The study indicates that, out-of-plane mechanical properties of the HONNs are generally superior to its in-plane mechanical properties. Whereas the CNT shows a significant strengthening effect on the out-of-plane mechanical properties of the CNHONN composites. Compared to pure HONNs, through the addition of CNTs from 1.28 wt‰ to 5.22 wt‰, the weight of the composite can be reduced by 5.83‰ to 2.33% while the tensile modulus, tensile strength, compressive modulus and compressive strength can be increased by 2.2% to 8.8%, 1% to 5.1%, 3.6% to 10.2% and 4.9% to 10.7%, respectively. The energy absorption capacity can also be improved due to the existence of CNTs. Furthermore, the MD simulations provide further insights into the deformation mechanism at the atomic scale, including fracture in tension, pore collapse in compression and local changes in lattice structures due to stacking faults.

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