China
Africa
Explore chapters and articles related to this topic
Effects of Performance Measures of Non-conventional Joining Processes on Mechanical Properties of Metal Matrix Composites
Published in Suneev Anil Bansal, Virat Khanna, Pallav Gupta, Metal Matrix Composites, 2023
Kamaljit Singh, Suneev Anil Bansal, Virat Khanna, Satinder Singh
MMCs are often joined with different welding techniques to enhance their practicability in the manufacturing and processing industries. However, producing a weld without any defect has been a great challenge with conventional fusion welding processes. Presently, EBW has been used widely by industries to fabricate distinct welding structures, especially from thicker materials up to 12 inches. In such cases, the traditional methods can drip out the molten metal from the molten weld pool from the backside (Terentyev et al., 2015). Moreover, the electron beam, in comparison to laser beam, provides an extreme fusion process and produces a weld with narrow material distortion. Also, electron beam welding can be distinguished from other traditional joining methods in terms of the energy source it employs. As shown in Figures 7.11a and b, it utilizes a beam of highly pulsed electrons that impinges on the materials, and the associated kinetic energy transforms into thermal energy. Consequently, the edges of the metals get fused due to the heat generated and join the different metal surfaces together after solidification (Biermann & Aneziris, 2020; Kalaiselvan et al., 2021).
Fabrication and Processing of Biodegradable Mg and Its Alloys
Published in Yufeng Zheng, Magnesium Alloys as Degradable Biomaterials, 2015
Electron beam welding (EBW) is a method of fusion welding that employs a dense stream of high-velocity electrons to bombard, heat, and melt the materials being joined. The electron beam is generated by an electron gun composed of a cathode made of tungsten and an anode placed in a high vacuum. When the electron beam moves forward, the melted and evaporated alloy flows from the front to the back of the keyhole. It is suitable for difficult welding in which high repeatability is required. Nevertheless, the volatilization of the Mg will contaminate the vacuum chamber. Electron-beam welding under nonvacuum conditions is more suitable for Mg alloys (Bach et al. 2003).
Joining of Metals
Published in Sherif D. El Wakil, Processes and Design for Manufacturing, 2019
Because of the ultra-high quality of the joints produced by electron-beam welding, the process has found widespread use in the atomic power, jet engine, aircraft, and aerospace industries. Nevertheless, the time required to vacuum the chamber before each welding operation results in reduced productivity, and, therefore, the high cost of the electron-beam welding equipment is not easily justified. This apparently kept the process from being applied in other industries until it was automated. Today, electron-beam welding is becoming popular for joining automotive parts such as gear clusters, valves, clutch plates, and transmission components.
Radiation Protection at Petawatt Laser-Driven Accelerator Facilities: The ELI Beamlines Case
Published in Nuclear Science and Engineering, 2023
Anna Cimmino, Veronika Olšovcová, Roberto Versaci, Dávid Horváth, Benoit Lefebvre, Andrea Tsinganis, Vojtěch Stránský, Roman Truneček, Zuzana Trunečková
The High-order Harmonic Generation18 (HHG) experiment is dedicated to the production of ultrashort pulses of tunable coherent extreme ultraviolet soft X-ray radiation using the L1-Allegra. The Plasma X-ray Source19 (PXS) experiment produces high-brightness X-ray beams with energies varying from 3 to about 77 keV using the L1-Allegra. The E2 X-ray Source, instead, is dedicated to the generation of ultrafast and bright hard X-rays using a PW-class laser with a 10-Hz repetition rate.20 It relies on the L3-HAPLS laser focused on gas targets. The Laser Undulator Incoherent Source (LUIS) experimental station aims to produce laser-driven electron beams for the generation of initially spontaneous, and subsequently coherent, photon radiation.21 The electron beams will have maximum energies of 600 MeV with a peak energy spread of less than 1%. The Electron Beam Accelerator (ELBA) for fundamental science and applications will accelerate electrons up to energies of tens of gigaelectron-volts.22 Both the LUIS and ELBA use the L3-HAPLS and in the future will also use the L2-DUHA and L4-Aton lasers.
Biogenic synthesis of gold nanoparticles using red seaweed Champia parvula and its anti-oxidant and anticarcinogenic activity on lung cancer
Published in Particulate Science and Technology, 2023
Sandhiya Viswanathan, Thirunavukkarasu Palaniyandi, P. Kannaki, Rajeshkumar Shanmugam, Gomathy Baskar, A. Mugip Rahaman, L. Tharrun Daniel Paul, Barani Kumar Rajendran, Asha Sivaji
The surface morphology of C. parvula extract-synthesized gold nanoparticles was analyzed by electron microscopy. An electron beam is used in electron microscopes, which interacts with nanomaterials and displays its precise morphological structure on image receiver plates (Dubau et al. 2013). The scanning electron microscope demonstrated that synthesized Cp-AuNPs were mostly round in shape (Figure 3). Furthermore, transmission electron microscopic analysis exhibited precise morphology and size of Cp-AuNPs. The TEM images of biosynthesized AuNPs at various magnifications as shown in (Figures 4(A,B)) which clearly showed the particles were mostly round in shape and some of the particles are spherical shapes with 20 nm in size. Previously, the marine algae Gracilaria verrucose-mediated AuNPs have been found spherical in shapes with <20 nm (Chellapandian et al. 2019). The SEM image of marine endophytic fungus mediated gold nanoparticles exhibited 60 nm in size (Manjunath Hulikere et al. 2017). The nanoparticles were aggregated into spherical and round patterns with various size range due to pH, temperature, and various biomolecules involved in the nanoparticle synthesis process (Kedi et al. 2018). Typical TEM and SEM microscopic images confirmed the average size and morphology of synthesized Cp-AuNPs.
The dépaysement art of the new media era incorporating the microscopic world
Published in Digital Creativity, 2021
Electron microscopes, which are generally used in various scientific experiments, are different from the lenses or light sources of optical microscopes. Electron microscopes use electron beams instead of visible light to create images. One can see the image through an optical microscope, but an electron microscope can see it through a fluorescent plate or a photographic plate. In addition, an optical microscope absorbs or reflects light from a sample to create an image. However, in an electron microscope, secondary electrons, reflected electrons, and X-rays generated when electron beams collide with the surface of the sample are measured, and the shape of the sample's surface is captured as a video.