Wyniki wyszukiwania - BazTech

1

Different Ignition Responses of Powdery and Bulky 1,3,5-Triamino-2,4,6-trinitrobenzene (TATB) Based Polymer-bonded Explosives under Ultra-high Voltage Electrostatic Discharge

Lyu Z., Long X., Li Z., Dai X., Deng C., He S., Li M., Yao K., Wen Y.

Central European Journal of Energetic Materials

|

2018

|

Vol. 15, no. 2

283--298

EN

The electric spark induced ignition mechanism for explosives needs further study. The ignition of powdery and bulky TATB by electrostatic discharge (ESD) was investigated. Up to 200 kV ultra-high voltage ESD was applied to powdery and bulky explosives of two TATB-based polymer-bonded explosives (named PBX-1 and PBX-2). The results showed that the spark sensitivities of powdery and bulky explosives are extremely different for the same formulation. The 50% ignition voltages of powdery PBX-1 and PBX-2 were 10.8 kV and 8.5 kV, respectively, while the values for the bulky samples (tablets) were not less than 200 kV. Both heat and the electric field can be transmitted into the powdery samples, on the other hand only the electric field can be transmitted into the bulk samples. The electric field has a smaller contribution while the heat has a larger contribution to the ignition during an ESD, i.e., the thermal effect plays a main role in the ignition process. Our experimental results are in good agreement with recent results calculated by density functional theory.

2

Computer Simulation of Processes Connected with Electron Donor Fluorescence Quenching in Rigid Matrices. Effect of an External Electric Field

Gutman M., Hilczer M.

Polish Journal of Chemistry

|

2008

|

Vol. 82, nr 12

2245-2253

EN

Computer simulation of photoexcited electron-donor D* fluorescence quenching in a rigid matrix has been performed. Three processes are assumed to occur: (1) the natural decay of D* excitation, (2) the electron transfer from D* to acceptor A, (3) migration of the excitation energy among D molecules. The effect of an external electric field F on process (2) has been included into considerations. Fluorescence decay curves calculated for various concentrations of D and the field-induced variation in the donor fluorescence intensity have been compared with respective experimental data and the results obtained from the approximate analytical calculations (hop ping model).

3

Electric Field Prediction for a Human Body-Electric Machine System

Ioannides M. G., Papadopoulos P. J., Dimitropoulou E.

International Journal of Occupational Safety and Ergonomics

|

2004

|

Vol. 10, No. 1

87--100

EN

A system consisting of an electric machine and a human body is studied and the resulting electric field is predicted. A 3-phase induction machine operating at full load is modeled considering its geometry, windings, and materials. A human model is also constructed approximating its geometry and the electric properties of tissues. Using the finite element technique the electric field distribution in the human body is determined for a distance of 1 and 5 m from the machine and its effects are studied. Particularly, electric field potential variations are determined at specific points inside the human body and for these points the electric field intensity is computed and compared to the limit values for exposure according to international standards.

4

Barrier effect on the dielectric strength of long oil gaps under lightning impulse voltages

Beroual A., Zouaghi A.

Archives of Electrical Engineering

|

1999

|

Vol. 48, nr 3

305-322

PL

Artykuł jest poświęcony badaniu wpływu przegród izolacyjnych na wytrzymałość elektryczną dużych odstępów olejowych w układzie ostrze - płyta. Analizowany jest wpływ znaku stosowanego napięcia, geometrii elektrod i przegród,, materiałów stosowanych przegród i ich pozycji względem elektrod a także obecności dziur w przegrodach i ich wpływu na rozkład pola elektrycznego. Pokazano, że efektywność działania przegrody (tzn. stosunek napięcia przebicia układu z przegrodą do napięcia przebicia bez przegrody) w układzie ostrze - płyta jest największy wtedy kiedy przegroda jest umieszczona przy elektrodzie ostrze, w odległości do 25% odstępu między elektrodami. Ta efektywność wzrasta ze wzrostem wymiarów przegród i maleje z powiększeniem odstępu między elektrodami. Przedstawiono także w artykule model pozwalający wyznaczyć optymalną pozycję przegrody.

EN

This paper deals with the insulating barriers effect on the dielectric strength of point-plane oil gaps under lightning impulse voltages. The influence of the polarity of the voltage, the electrode geometry, the nature, the dimensions and the position of the barrier, the presence of holes within the barrier and the electric field distribution are investigated. It is shown that the efficiency of an insulating barrier, namely the ratio of the breakdown voltage of oil gaps in presence of barrier to that one without barrier, in a divergent electrode system, is higher when the barrier is inserted near the sharp electrode (at 0 to 25% of the electrode gap). This efficiency increases with the diameter of the barrier and decreases when the electrode gap increases. A model allowing to estimate the optimal position of the barrier is presented.