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Published in Maurizio Cumo, Antonio Naviglio, Safety Design Criteria for Industrial Plants, 2019
Claudia Bartolomei, Sergio Paribelli
Special precautions and preventive measures — Protect containers against physical damage. Outdoor or detached and isolated storage is preferred. For inside storage combustible liquid storage rooms are preferred but separate from halides and other oxidizing materials. Vapor may form explosive mixtures with air. Protect against electric spark, open flame, or other ignition sources. Wear rubber gloves and self-contained breathing apparatus. Tetramethyl lead will attack some forms of rubber, plastics, and coatings. Physical examination should be made available to exposed personnel.
Offshore Production
Published in Sukumar Laik, Offshore Petroleum Drilling and Production, 2018
An electrical spark near a flammable substance can cause serious fire hazard. A fire or explosion can occur if a flammable atmosphere and a source of ignition (spark) exist together. To avoid this, special electrical equipment is to be used depending on the area. In a zone 0 area, it is preferable to avoid all electrical equipment; otherwise, only intrinsically safe type equipment can be used. In the case of zone 1, only ‘certified flameproof’ electrical equipment can be used. If the area comes under the category of zone 2, ‘non-sparking’ types of electrical equipment can be used.
Incendiary Terrorism
Published in Robert A. Burke, Counter-Terrorism for Emergency Responders, 2017
Electrical distribution systems have many safeguards built into them to help prevent fire. Someone who wants a fire to occur could compromise some of these safeguards. Tampering with circuit breakers or fuses can cause a fire to start. Undersized electrical cords, extension cords, oversized light bulbs, or placement of a combustible material against a hot light bulb can all be efforts to start an incendiary fire. The investigator needs to look carefully at the electrical system for signs of tampering or electrical shorts that might not be explainable by natural causes. Spark is a term that has several definitions and must be further explained. A spark can refer to an electrical spark, which is the discharge of electrical current through the air or another insulator. Another type of spark is a small particle of a burning or glowing solid material moving through the air. Both of these types of sparks are likely to be hot enough to ignite vapors and some solid fuels. Particulate sparks can be produced from two dissimilar materials, such as flint and steel, or by significant frictional contact between two materials.
Developments in tandem micro-machining processes to mitigate the machining issues at micron level: a systematic review, challenges and future opportunities
Published in Machining Science and Technology, 2022
Sahil Sharma, Tarlochan Singh, Akshay Dvivedi
Beyond the critical voltage, the density of hydrogen bubbles around the cathode surface exceeds the density of hydrogen bubbles in the electrolyte. These bubbles accumulate and form a thin layer around the tool electrode surface (Figure 33b and c). The developed film acts as a dielectric medium that restricts the flow of current for a short period and thus generates a high electric field of magnitude 10 V/µm across the dielectric film. This immense electric field expedites an electric spark between tool and electrolyte. The spark initiates from the tool edge and finally covers the entire bottom of the tool (Figure 33d), resulting in further increase in voltage. These discharges are responsible for melting, and even vaporization of work material and hence form a desire crater at the work surface. Moreover, the continuous bombardment of discharges also increases the electrolyte temperature, thereby promoting the etching of the workpiece by electrochemical dissolution. The combined action of electro-discharge erosion and electrochemical etching causes faster removal of material from the desired location. The ECDMed components are known to have several surface defects, namely, large HAZ, uneven layers of resolidified layers, micro-cracks, etc., and thus require secondary machining operation to produce smooth surfaces.
Electric discharge synthesis of nickel nanoparticles with virtual instrument control
Published in Instrumentation Science & Technology, 2021
Rogelio Ramos, Benjamin Valdez, Nicola Nedev, Mario Curiel, Oscar Perez, Jorge Salvador
The most commonly used methods of the top-down approach are thermal and plasma vaporization,[3] laser ablation,[12] and arc discharge.[13,14] An advantage of the physical methods is the possibility to prepare nanoparticles with high purity since no chemical precursors are used. The electric arc discharge method has evolved with time and is known under various names including submerged arc nanoparticle synthesis,[15] micro-electrical discharge machining,[16] and electric spark discharge.[17] Submerged arc nanoparticle synthesis has been used to prepare Ag nanoparticles in deionized water in the 6 to 25 nm range.[15] Nanoparticle suspension containing metallic Ag nanoparticles and ionic Ag in ethylene glycol has been fabricated by an arc discharge without any surfactant.[13] The electric arc discharge method has also been used to prepare gold,[13] aluminum,[16,18] and iron[14] nanoparticles. However, to the best of our knowledge, the method has not yet been used to prepare colloidal suspensions of nickel nanoparticles.
Toward green electrical discharge machining (EDM): state of art and outlook
Published in Machining Science and Technology, 2023
Israa Dheyaa Khalaf Alrubaye, Gualtiero Fantoni
The most critical challenge of the EDM process is the low material removal rate, resulting in low process efficiency. The EDM efficiency could be improved if there is no interruption during the removal of material caused by the ignition delay and discharge interval. Therefore, the EDM should work in continuously burning electric arcs. The electric arc has a longer discharge time than an electric spark, resulting in more powerful output energy with higher MRR and efficiency. But, if the discharge of the electric arc remains at a specific location, that will result in severe brutal burning for the electrode and the workpiece. Some studies proposed different methods to solve this problem of electric arc (Zhaojun and Fuzhu, 2018).