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Reexamination of the Branly effect.
S Dorbolo1, M Ausloos, N Vandewalle
1GRASP, Institut de Physique B5, Université de Liège, Belgium.
Summary
Sparks from a burster reduce the electrical resistance of metallic granular packing. This resistance decrease follows a stretched exponential law, indicating a diffusion-like process of new electrical path creation.
Area of Science:
- Physics
- Materials Science
Background:
- The electrical resistance of metallic granular packing is sensitive to external stimuli.
- Gustave Branly's work described spark-induced resistance changes in granular conductors.
Purpose of the Study:
- To investigate the electrical resistance behavior of metallic granular packing under spark-induced conditions.
- To characterize the underlying physical process governing resistance variations.
Main Methods:
- Recording electrical resistance of metallic granular packing at room temperature.
- Introducing sparks from a nearby burster to induce resistance changes.
- Analyzing resistance variations using mathematical models, specifically the stretched exponential law.
Main Results:
- A continuous decrease in electrical resistance was observed upon sparking.
- Resistance variations were found to follow a stretched exponential law.
- The observed behavior was identified as analogous to nucleation-growth soldering processes and a diffusion-like process.
Conclusions:
- Spark-induced resistance changes in granular packing are continuous and follow a predictable mathematical law.
- The creation of new electrical paths, similar to nucleation-growth, drives the resistance decrease.
- The phenomenon exhibits characteristics of a diffusion-like process.