scholarly journals Microwave Assisted Manufacturing and Repair of Carbon Reinforced Nanocomposites

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Edward D. Sosa ◽  
Erica S. Worthy ◽  
Thomas K. Darlington
Keyword(s):  
Interfacial Adhesion ◽  
Advanced Manufacturing ◽  
Composite Repair ◽  
X Ray ◽  
Microwave Exposure ◽  
Microwave Assisted ◽  
Lap Shear ◽  
Damage Repair ◽  
The Matrix ◽  
X Ray Computed

We report a composite capable of advanced manufacturing and damage repair. Microwave energy is used to induce thermal reversible polymerization of the matrix allowing for microwave assisted composite welding and repair. Composites can be bonded together in just a few minutes through microwave welding. Lap shear testing demonstrates that microwave welded composites exhibit 40% bond strength relative to composites bonded with epoxy resin. Double cantilever beam testing shows 60% recovery in delamination strength after microwave assisted composite repair. The interfacial adhesion and composite repair after microwave exposure are examined by X-ray computed tomography. The microwave processing is shown to be reproducible and consistent. The ability to perform scalable manufacturing is demonstrated by the construction of a large structure from smaller components.

Synchrotron Microtomography of Composites

1988 ◽  
Vol 143 ◽  
Author(s):  
S. R. Stock ◽  
J. H. Kinney ◽  
T. M. Breunig ◽  
U. Bonse ◽  
S. D. Antolovich ◽  
...  
Keyword(s):  
Charge Coupled Device ◽  
High Brightness ◽  
X Ray ◽  
Three Point Bending ◽  
Ccd Detector ◽  
The Matrix ◽  
Dimensional Distribution ◽  
X Ray Computed ◽  
Synchrotron Microtomography

AbstractX-ray computed tomography (CT) uses absorption profiles from many different viewing directions to reconstruct the two-dimensional distribution of x-ray absorptivity within a slice of the sample. The tunability, high brightness and parallelism of synchrotron radiation are critical to high resolution (0.001mm), high contrast (1%) CT or microtomography. In situ study of samples multiple times during the course of an experiment is exciting to consider.Continuous fiber SiC/Al composites were deformed under three-point bending, and the resulting damage and fiber arrangement were revealed with synchrotron microtomography. Several hundred slices of 0.012 mm thickness were recorded simultaneously using 25 key radiation and a phosphor screen/charge coupled device (CCD) detector. Reconstruction was with the filtered back projection method. Low density regions were observed in the matrix in regions of highest stress where cracking is expected.

scholarly journals Investigation of Microstructural Damage in Ultrahigh-Performance Concrete under Freezing-Thawing Action

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Chunping Gu ◽  
Wei Sun ◽  
Liping Guo ◽  
Qiannan Wang ◽  
Jintao Liu ◽  
...  
Keyword(s):  
Mercury Intrusion Porosimetry ◽  
Steel Fibers ◽  
X Ray ◽  
Microstructural Damage ◽  
Dense Microstructure ◽  
Thermal Expansion Coefficients ◽  
Before And After ◽  
The Matrix ◽  
X Ray Computed ◽  
Expansion Coefficients

This work aims to investigate the damage in ultrahigh-performance concrete (UHPC) caused by freezing-thawing action. Freezing-thawing tests were carried out on UHPCs with and without steel fibers. Mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), and X-ray computed tomography (X-ray CT) were applied to detect the microstructure of the UHPC matrix before and after the freezing-thawing tests. The results showed that UHPC possessed very excellent freezing-thawing resistance due to its dense microstructure. After the freezing-thawing action, cracks occurred and were prone to initiate at the sand-paste interface in the UHPC matrix. MIP results also indicated that cracks appeared in the UHPC matrix after the freezing-thawing action. The number of defects that can be seen by X-ray CT increased in UHPC after the freezing-thawing action as well. The mismatch of the thermal expansion coefficients of the aggregate and the paste is considered to be the reason for the cracking at the sand-paste interface. The steel fibers in UHPC inhibited the propagation of cracks in the matrix and improved the freezing-thawing performance of UHPC.

On Microstructure and Wear Behavior of Microwave Processed Composite Clad

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Sarbjeet Kaushal ◽  
Dheeraj Gupta ◽  
Hiralal Bhowmick
Keyword(s):  
Wear Behavior ◽  
Wear Test ◽  
Dry Sliding Wear ◽  
X Ray ◽  
Microwave Exposure ◽  
Interfacial Cracks ◽  
The Matrix ◽  
Xrd Patterns ◽  
Vicker’S Microhardness ◽  
Ss 304

In the present study, wear resistance composite cladding of Ni-based + 20% WC8Co (wt. %) was developed on SS-304 substrate using domestic microwave oven at 2.45 GHz and 900 W. The clad was developed within 300 s of microwave exposure using microwave hybrid heating (MHH) technique. The clad was characterized through scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Vicker’s microhardness, and dry sliding wear test. Microstructure study revealed that the clad of approximately 1.25 mm thickness was developed by partial mutual diffusion with substrate. It was observed that the developed clad was free from visible interfacial cracks with significantly less porosity (∼1.2%). XRD patterns of the clad confirmed the presence of Cr23C6, NiSi, and NiCr phases that eventually contributed to the enhancement in clad microhardness. Vicker’s microhardness of the processed clad surface was found to be 840 ± 20 HV, which was four times that of SS-304 substrate. In case of clad surface, wear mainly occurs due to debonding of carbide particles from the matrix, while plastic deformation and strong abrasion are responsible for the removal of material from SS-304 substrate.

scholarly journals Encapsulation of Upconversion Nanoparticles in Periodic Mesoporous Organosilicas

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4054 ◽  
Author(s):  
Saher Rahmani ◽  
Chiara Mauriello Jimenez ◽  
Dina Aggad ◽  
Daniel González-Mancebo ◽  
Manuel Ocaña ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Near Infrared ◽  
Sol Gel ◽  
Upconversion Nanoparticles ◽  
X Ray ◽  
Mesoporous Organosilica ◽  
The Matrix ◽  
X Ray Computed ◽  
Mesoporous Organosilicas ◽  
Cancer Theranostics

(1) Background: Nanomedicine has recently emerged as a promising field, particularly for cancer theranostics. In this context, nanoparticles designed for imaging and therapeutic applications are of interest. We, therefore, studied the encapsulation of upconverting nanoparticles in mesoporous organosilica nanoparticles. Indeed, mesoporous organosilica nanoparticles have been shown to be very efficient for drug delivery, and upconverting nanoparticles are interesting for near-infrared and X-ray computed tomography imaging, depending on the matrix used. (2) Methods: Two different upconverting-based nanoparticles were synthesized with Yb3+-Er3+ as the upconverting system and NaYF4 or BaLuF5 as the matrix. The encapsulation of these nanoparticles was studied through the sol-gel procedure with bis(triethoxysilyl)ethylene and bis(triethoxysilyl)ethane in the presence of CTAB. (3) Results: with bis(triethoxysilyl)ethylene, BaLuF5: Yb3+-Er3+, nanoparticles were not encapsulated, but anchored on the surface of the obtained mesoporous nanorods BaLuF5: Yb3+-Er3+@Ethylene. With bis(triethoxysilyl)ethane, BaLuF5: Yb3+-Er3+ and NaYF4: Yb3+-Er3+nanoparticles were encapsulated in the mesoporous cubic structure leading to BaLuF5: Yb3+-Er3+@Ethane and NaYF4: Yb3+-Er3+@Ethane, respectively. (4) Conclusions: upconversion nanoparticles were located on the surface of mesoporous nanorods obtained by hydrolysis polycondensation of bis(triethoxysilyl)ethylene, whereas encapsulation occurred with bis(triethoxysilyl)ethane. The later nanoparticles NaYF4: Yb3+-Er3+@Ethane or BaLuF5: Yb3+-Er3+@Ethane were promising for applications with cancer cell imaging or X-ray-computed tomography respectively.

Mechanical Properties of TPNR-MWNTs-OMMT Hybrid Nanocomposites

2012 ◽  
Vol 501 ◽  
pp. 194-198 ◽  
Author(s):  
Mou'ad A. Tarawneh ◽  
Sahrim H. Ahmad ◽  
A.R. Shamsul Bahri ◽  
Yu Lih Jiun
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aspect Ratio ◽  
Interfacial Adhesion ◽  
Hybrid Nanocomposites ◽  
X Ray Diffraction ◽  
Elongation At Break ◽  
X Ray ◽  
Maximum Value ◽  
The Matrix

This paper discusses the processing of a hybrid of TPNR-MWNTs-OMMT nanocomposites with different percentages of filler to determine the optimum mechanical properties of the hybrid nanocomposites. Three types of hybrid nanocomposites with various MWNTs-OMMT compositions (1%wt MWNTs+3%wt OMMT), (2%wt MWNTs+2%wt OMMT) and (3%wt MWNTs+1%wt OMMT) were prepared. The OMMT layers were found to be separated further with higher nanotubes content as exhibited by X-ray diffraction. The result of tensile test showed that tensile strength and Young's modulus increase in the presence of nanotubes and maximum value were obtained for the nanocomposites with highest nanotubes (3%wt) which increased about 33% and 36%, respectively compared with pure TPNR matrix. On other hand, the elongation at break considerably decreased with increasing the percentage of MWNTs. TEM micrographs revealed aspect ratio and fillers orientation in the TPNR matrix also promoted strongly to interfacial adhesion between fillers and the matrix which contributed significantly to the improvement of the mechanical properties

Cu (II) coordination modification of aramid fiber and effect on interfacial adhesion of composites

2018 ◽  
Vol 31 (9-10) ◽  
pp. 1054-1061 ◽  
Author(s):  
Ting Li ◽  
Zengxiao Wang ◽  
Junrong Yu ◽  
Yan Wang ◽  
Jing Zhu ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Interfacial Adhesion ◽  
Interfacial Shear Strength ◽  
Copper Ion ◽  
Aramid Fiber ◽  
Single Fiber ◽  
Epoxy Composites ◽  
X Ray ◽  
Pull Out ◽  
The Matrix

In this article, active groups were introduced to the surface of aramid fiber by building a Cu2+ bridge between the aramid fiber and polyethyleneimine (PEI) to improve adhesion in composites between the aramid fiber and the matrix such as epoxy resin. The changes in the structure and properties of the aramid fiber were verified with Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and the single-fiber pull-out test. The FTIR and XPS results show a significant change in the structure and morphology of the aramid fiber after modification. The results of the single-fiber pull-out test show that the interfacial shear strength (IFSS) of epoxy composites reinforced with PEI-grafted aramid fiber increases by 48.8% compared with the IFSS of epoxy composites reinforced with untreated fiber. Thus, the proposed method can improve the interfacial bonding of composites by creating a copper ion bridge between the aramid fiber and PEI.

scholarly journals Modeling of Laser-Induced Plasmon Effects in GNS-DLC-Based Material for Application in X-ray Source Array Sensors

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1248
Author(s):  
Alexander N. Yakunin ◽  
Sergey V. Zarkov ◽  
Yuri A. Avetisyan ◽  
Garif G. Akchurin ◽  
Nikolay P. Aban’shin ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Current Source ◽  
Scanning Speed ◽  
High Energy ◽  
Localized Surface Plasmon ◽  
X Ray ◽  
The Matrix ◽  
New Material ◽  
X Ray Computed ◽  
Thermal Sources

An important direction in the development of X-ray computed tomography sensors in systems with increased scanning speed and spatial resolution is the creation of an array of miniature current sources. In this paper, we describe a new material based on gold nanostars (GNS) embedded in nanoscale diamond-like carbon (DLC) films (thickness of 20 nm) for constructing a pixel current source with photoinduced electron emission. The effect of localized surface plasmon resonance in GNS on optical properties in the wavelength range from UV to near IR, peculiarities of localization of field and thermal sources, generation of high-energy hot electrons, and mechanisms of their transportation in vacuum are investigated. The advantages of the proposed material and the prospects for using X-ray computed tomography in the matrix source are evaluated.

Lateral resolution of the electron microbeam analysis

1978 ◽  
Vol 36 (1) ◽  
pp. 542-543
Author(s):  
H.J. Dudek
Keyword(s):  
Quantitative Analysis ◽  
Depth Resolution ◽  
Lateral Resolution ◽  
Cylindrical Particle ◽  
Correction Procedure ◽  
X Ray ◽  
Element Concentrations ◽  
Microbeam Analysis ◽  
The Matrix

The chemical inhomogenities in modern materials such as fibers, phases and inclusions, often have diameters in the region of one micrometer. Using electron microbeam analysis for the determination of the element concentrations one has to know the smallest possible diameter of such regions for a given accuracy of the quantitative analysis.In th is paper the correction procedure for the quantitative electron microbeam analysis is extended to a spacial problem to determine the smallest possible measurements of a cylindrical particle P of high D (depth resolution) and diameter L (lateral resolution) embeded in a matrix M and which has to be analysed quantitative with the accuracy q. The mathematical accounts lead to the following form of the characteristic x-ray intens ity of the element i of a particle P embeded in the matrix M in relation to the intensity of a standard S

Analysis and lattice imaging of a transitional event on garnets

1978 ◽  
Vol 36 (1) ◽  
pp. 270-271
Author(s):  
J.Y. Laval
Keyword(s):  
Yttrium Iron Garnet ◽  
Reciprocal Lattice ◽  
Transitional Zone ◽  
Lattice Imaging ◽  
Yttrium Iron ◽  
X Ray ◽  
Ionic Process ◽  
The Matrix ◽  
High Resolution Technique ◽  
Iron Garnet

The exsolution of magnetite from a substituted Yttrium Iron Garnet, containing an iron excess may lead to a transitional event. This event is characterized hy the formation of a transitional zone at the center of which the magnetite nucleates (Fig.1). Since there is a contrast between the matrix and these zones and since selected area diffraction does not show any difference between those zones and the matrix in the reciprocal lattice, it is of interest to analyze the structure of the transitional zones.By using simultaneously different techniques in electron microscopy, (oscillating crystal method microdiffraction and X-ray microanalysis)one may resolve the ionic process corresponding to the transitional event and image this event subsequently by high resolution technique.

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