Electric arc source for high‐frequency seismic measurement

2000 ◽  
Vol 107 (5) ◽  
pp. 2897-2897
Author(s):  
James S. Martin ◽  
Gregg D. Larson ◽  
Peter H. Rogers ◽  
Waymond R. Scott
2002 ◽  
Vol 16 (4) ◽  
pp. 317-319
Author(s):  
S M Burdakov ◽  
A V Chernov ◽  
Yu V Poletaev ◽  
S V Polezhaev

Science ◽  
1953 ◽  
Vol 118 (3054) ◽  
pp. 43-44 ◽  
Author(s):  
K. A. Wilde ◽  
B. J. Zwolinski ◽  
R. B. Parlin
Keyword(s):  

2019 ◽  
Vol 140 ◽  
pp. 05001
Author(s):  
Andrei Brilinskii ◽  
Georgiy Evdokunin ◽  
Anna Petrova ◽  
Irina Ryndina

The article comprises the results of the research defining open-flame arcs self-quenching conditions in the event of a single phase-to-ground fault in overhead medium-voltage distribution networks according to existing theories of arc extinguishing. The calculations included metallic and arc faults modeling in a network with low phase-to-ground fault current. The arc gap simulation based on the mathematical channel model of a cylindrically symmetrical upright arc stabilized by rising convective gas flow was carried out in ATPDraw software program. The single phase-to-ground arc fault calculations results indicated an increase in high-frequency currents’ attenuation rate during transient processes as well as a reduce reduction in the electric arc lifetime from 8 ms to 2 ms in case of the breakdown voltage decrease from the peak value to zero. Notably, in case of low single phase-to-ground fault current the arc extinguishing took place at the first high-frequency current zero. For the cases of nonzero breakdown voltages, the electric arc extinguishing was detected at the fundamental frequency current component zero-crossing instant. The maximum overvoltage ratio of K = 2.8 was obtained as athe result of the single phase-to-ground fault at the peak phase voltage.


Author(s):  
Antoni Sawicki

The article presents selected physical properties of electric arc used in welding engineering as well as discusses differences in requirements concerning ionisers used to initiate and re-initiate electric arc. In addition, the article compares properties of ioniser systems used to stabilise electric arc burning as well as discusses spark gap and semiconductor systems generating high-frequency and high-voltage impulses used to generate spark discharges. The article also discusses the effect of ioniser operation after the modification of static current-voltage characteristics, enabling the modelling of dynamic states of electric arc.


2021 ◽  
pp. 49-60
Author(s):  
Antoni Sawicki

The second part of the overview article discusses general features of the design and operation of selected industrial arc plasma torches. Because of their structural and operating differences, plasma torch power supply systems with internal and partly external arc are discussed separately. Particular attention was paid to the design of electric systems used for the initiation of arc discharges. Because of the fact that the operation of plasma torches with partly external arc is often accompanied by the formation of double arc, the article also presents measures and methods enabling the prevention of the aforesaid unfavourable phenomenon. In addition, the article discusses selected technological properties of plasma torches and micro-plasma torches used for joining, cutting, surfacing and hardening.


Author(s):  
I.E. Kolesnichenko ◽  
E.A. Kolesnichenko ◽  
E.I. Lyubomishchenko ◽  
E.I. Kolesnichenko ◽  
A.A. Evsyukova

Fires and explosions pose the greatest threat in underground mines that use high-voltage electrical grids. The paper presents data on explosions of combustible methane and coal dust mixtures in Russian mines. It is shown that there always exists a high risk of fire resulting from a malfunction in the electrical grid. The research aims at determining the type and parameters of an electric arc, spark or open flame generated at the breaking points of electric conductors which initiate the ignition of a combustible medium. It was found that the commonly known ionic and thermal theories of ignition do not match the present state of knowledge. The methodology consisted in investigating patterns of electric charge generation and transfer up to the point of the mains failure. Regularities of energy processes in the atomic and molecular structure of the conductor material are presented. For the first time ever the concept of transformation of the electromagnetic energy generated in the alternator into photon packets of high-frequency energy is justified. An electron of the conductor atom absorbs a quantum of the generated energy, converts the generated frequency into a high-frequency photon packet and radiates it into the electric grid. It has been found that an electric arc or a spark, acting as a source of ignition for a combustible medium, is an electromagnetic emission of energy in the visible range.


Science ◽  
1953 ◽  
Vol 118 (3054) ◽  
pp. 43-44
Author(s):  
Kenneth A. Wilde ◽  
Bruno J. Zwolinski ◽  
Ransom B. Parlin
Keyword(s):  

2019 ◽  
Vol 1153 ◽  
pp. 52-57
Author(s):  
Emilia Florina Binchiciu ◽  
Ionelia Voiculescu ◽  
Victor Geantă ◽  
Nicușor Alin Sîrbu ◽  
Ion Aurel Perianu

We present the manufacturing process, by melting in a controlled environment, of specific alloys that have a benefic effect on the diffusion phenomena’s in the base material of the addition coated rods for brazing. The friable precursors obtained by melting are grinded with the purpose of integrating them in the coat of the rods, namely the addition material. The metallurgic activation activity of the precursors is enhanced by using them as nano-powders in the coat of the rods.Of major importance for deep joint capillary brazing are the fluidity and superficial tension of the melt - addition material, or, in case of non-ferrous alloys, the degree of de-oxidation of base materials. In order to improve the above mentioned characteristics, we made precursors type: 5o% Cu-45% Sn-5% P (CIF); 92% Cu-2% Si 6% P- (RAV). The batch design was done by two distinct melting processes, in high frequency currents (CIF) and electric arc (RAV) in a controlled environment. The melts were cast in graphite forms as loose briquettes. The briquettes thus obtained were analyzed structurally and sclerometrically, and after testing, they were grinded in planetary mills until we obtained nano-powders. The resulting powders will be used, as required, to prepare brazing sheaths.


Author(s):  
J. R. Porter ◽  
J. I. Goldstein ◽  
D. B. Williams

Alloy scrap metal is increasingly being used in electric arc furnace (EAF) steelmaking and the alloying elements are also found in the resulting dust. A comprehensive characterization program of EAF dust has been undertaken in collaboration with the steel industry and AISI. Samples have been collected from the furnaces of 28 steel companies representing the broad spectrum of industry practice. The program aims to develop an understanding of the mechanisms of formation so that procedures to recover residual elements or recycle the dust can be established. The multi-phase, multi-component dust particles are amenable to individual particle analysis using modern analytical electron microscopy (AEM) methods.Particles are ultrasonically dispersed and subsequently supported on carbon coated formvar films on berylium grids for microscopy. The specimens require careful treatment to prevent agglomeration during preparation which occurs as a result of the combined effects of the fine particle size and particle magnetism. A number of approaches to inhibit agglomeration are currently being evaluated including dispersal in easily sublimable organic solids and size fractioning by centrifugation.


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