Purification of SWNTs Using Microwave Heating

2001 ◽  
Vol 706 ◽  
Author(s):  
Avetik R. Harutyunyan ◽  
Bhabendra K. Pradhan ◽  
Gamini U. Sumanasekera ◽  
Jiping Chang ◽  
Gugang Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Microwave Heating ◽  
Acid Treatment ◽  
Carbon Coating ◽  
Single Wall Carbon Nanotubes ◽  
Metal Catalyst ◽  
Thermo Gravimetric ◽  
Mild Acid ◽  
Scanning Electron

AbstractA new method for purifying single wall carbon nanotubes (SWNTs) using microwave heating is developed. The microwaves couple to the residual metal catalyst, raising significantly the local temperature leading to both the oxidation and rupturing of the carbon passivation layer over the metal catalyst particles and sintering. With this protective carbon coating weakened or removed, a mild acid treatment in HCl is then sufficient to remove most of the metal in the sample, leaving the nanotubes in tact. Results from transmission and scanning electron microscopy (TEM & SEM), Raman spectroscopy and thermo-gravimetric studies are discussed.

scholarly journals Reduction and Dissolution Behaviour of Manganese Slag in the Ferromanganese Process

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 97 ◽  
Author(s):  
Xiang Li ◽  
Kai Tang ◽  
Merete Tangstad
Keyword(s):  
Electron Microscopy ◽  
South Africa ◽  
Scanning Electron Microscopy ◽  
Liquidus Temperature ◽  
Reduction Rate ◽  
Manganese Ore ◽  
Thermo Gravimetric ◽  
Dissolution Behaviour ◽  
Manganese Slag ◽  
Scanning Electron

The reduction and liquidus behaviour of manganese slag with different basicities were studied in non-isothermal experiments in the temperature range of 1400–1500 °C. Certain amounts of quartz were added to Assmang ore (South Africa), and lime was added to Comilog ore (Gabon), to adjust the charge basicity to 0.5, 0.8 and 1.2. The extent of manganese ore reduction as a function temperature were determined by thermo-gravimetric (TG) balance. Morphology of ores and its change in the course of reduction was examined by scanning electron microscopy (SEM). The results show that the reduction rate of Assmang slag decreases with decreasing basicity, as the liquidus temperature of slag decreases. When spherical MnO phase is present, the activity of MnO is high, and the reduction rate is rapid. Comilog slags show a much higher reduction rate than Assmang slags. The activation energies of MnO reduction between 1400 to 1500 °C are estimated in this study and found to be 230 kJ/mol for Assmang charges and 470 kJ/mol for Comilog charges. The dissolution behaviours of Assmang and Comilog slags were also studied by FactSage simulation and verified by experiments.

Preparation of Flower-Like Silica Microstructures

2010 ◽  
Vol 123-125 ◽  
pp. 1295-1298
Author(s):  
Wen Qi Wang ◽  
Zhen Sheng Peng
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silicon Oxide ◽  
Silicon Monoxide ◽  
Metal Catalyst ◽  
X Ray ◽  
Transmission Electron ◽  
Silicon Silicon ◽  
Scanning Electron

Novel flower-like silica microstructures have been synthesized through heating silicon, silicon monoxide and active carbon mixed powders under an H2/Ar (3%) atmosphere at 1050°C without assistance of any metal catalyst. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and energy dispersive x-ray spectrometer (EDS) analyses reveal that the wires are amorphous and consist only of silicon oxide, generated from the reaction of CO with SiC. A possible growth model based on both of vapor-solid (VS) and the Oxide-assisted growth (OAG) mechanism has been supposed here to explain this phenomenon.

scholarly journals Keratin Fibres IV. Structure of Cuticle

1970 ◽  
Vol 23 (4) ◽  
pp. 843 ◽  
Author(s):  
JH Bradbury ◽  
JD Leeder
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Formic Acid ◽  
Acid Treatment ◽  
Scanning Electron ◽  
Keratin Fibres

The cuticle structure of keratin fibres of placental mammals, marsupials, and monotremes has been examined by the techniques of light microscopy and scanning electron microscopy. These techniques have been used to study both intact fibres and whole cuticle cells separated by formic acid treatment.

Application of high-pressure scanning electron microscopy (ECO-SEM) in forensic sample analysis

1996 ◽  
Vol 54 ◽  
pp. 848-849
Author(s):  
Thomas A. Kubic ◽  
JoAnn Buscaglia
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Pressure ◽  
Carbon Coating ◽  
High Vacuum ◽  
Controlled Environment ◽  
Sample Analysis ◽  
Sample Chamber ◽  
Forensic Sample ◽  
Scanning Electron

Traditionally to obtain satisfactory images and reasonable resolution with a Scanning Electron Microscope (SEM), it has been necessary to employ a high vacuum within the sample chamber.High vacuum can result in the dehydration of materials with an alteration of sample morphology and in some cases the introduction of artifacts. In such an environment, samples that are nonconductive experience extensive charging with image degradation. Samples of forensic concern, such as textile bundles or swatches, exhibit this problem even after the application of metal coating. The problem is even more pronounced when carbon coating is used, as is often the preference of forensic microscopists in order to simplify interpretation of the EDX spectra.The commercial availability of "high pressure" or controlled environment SEMs that operate with sample chamber pressures from 50 to 4000 millitorr, while the electron guns and columns are kept at high vacuum conditions have solved these problems. The presence of this "higher" pressure retards dehydration while charging effects are nearly eliminated.

Influence of microwave heating on metallurgical and mechanical properties of Ni-40Cr3C2 composite clads in the context of cavitation erosion resistance characteristics

2020 ◽  
pp. 095440622094034
Author(s):  
Jonty Mago ◽  
Sandeep Bansal ◽  
Dheeraj Gupta ◽  
Vivek Jain
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Scanning Electron Microscopy ◽  
Flexural Strength ◽  
Microwave Heating ◽  
Cavitation Erosion ◽  
Erosion Resistance ◽  
Material System ◽  
Cavitation Erosion Resistance ◽  
Scanning Electron

Surface modification is one of the most reliable solutions for protecting the material damage in hydraulic turbines due to cavitation phenomena. However, the conventional coating/cladding process has many drawbacks like high porosity, weak adhesion strength, and poor fracture toughness. In contrast, the cladding process with microwave hybrid heating can overcome these limitations. Hence, this study aims to develop the microwave processed composite clad of Ni-based alloy with 40% Cr3C2 (by wt.) on SS-316 substrate in the domestic microwave oven of 2.45 GHz frequency and 900 W power. The selection of the material system for this study was based on mitigating the effect of cavitation erosion. The thorough metallurgical and mechanical characterization of the developed composite clad was done. Microstructural characterization using scanning electron microscopy revealed that the developed composite clads had a uniform thickness of 600 µm and free from interfacial cracks and visible pores (measured porosity ∼1.67% – as per ASTM B276). Uniformly dispersed hexagonal and stripe type carbides precipitate in the Ni-based alloy matrix of the composite clad was observed through scanning electron microscopy images. X-ray diffraction analysis shows that various hard carbides (SiC, Ni3C, Cr3Ni2SiC, Cr7C3, and NiC) and intermetallic (Ni3Fe, Ni2Si, and Cr3Si) phases were formed during microwave heating. The microhardness, flexural strength, fracture toughness of the Ni-40Cr3C2 clads were evaluated. The results reveal that the composite clad possesses microhardness = 605 ± 80 HV0.3 (∼3 times SS-316), flexural strength = 813.23 ± 16.2 MPa, and fracture toughness = 7.44 ± 0.2 MPa√m. The appropriate value of these properties makes this composite clad suitable for cavitation erosion resistance application.

Nanostructured Morphology of Spinel LiMn2O4 Oxide under Microwave Heating

2014 ◽  
Vol 936 ◽  
pp. 452-458
Author(s):  
Di Huo
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Morphology ◽  
Microwave Heating ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Conditions ◽  
Morphology And Structure ◽  
Scanning Electron

The surface morphology and structure of the cubic stoichiometric spinel LiMn2O4powder prepared by microwave heating were examined using X-ray diffraction, scanning electron microscopy and transmittance electron microcopy. It is shown that the surface morphology of LiMn2O4particle changed with increasing preparing temperature, while the crystal structure kept unchanged. Novel nanostructured morphologies including nanorods and nanowhiskers were formed under appropriate synthesis conditions. The growth mechanism of the nanostructured morphology of spinel LiMn2O4was discussed in accordance with period bonding chains (PBCs) theory.

Extraction of Nanocellulose from Sugarcane Bagasse

2014 ◽  
Vol 633-634 ◽  
pp. 550-553 ◽  
Author(s):  
Qing Wang ◽  
Ya Hui Zhang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Aspect Ratio ◽  
Sugarcane Bagasse ◽  
High Aspect Ratio ◽  
Acid Treatment ◽  
Scanning Electron ◽  
Nanowire Structure

Sugarcane bagasse was used as start materials to extract nanocellulose fibers. The morphology was investigated by scanning electron microscopy. The result indicated that the nanocellulose is successfully extracted by a series of alkali and acid treatment. The nancellulose is characterized by nanowire structure, and possesses high aspect ratio.

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