Faraday cage effect

Another technique to reduce back-ionization is to control the gun current. Controlling gun current helps reduce excessive free ions by automatically reducing the electrode voltage when the gun-to-part distance decreases. This method reduces back-ionization and the Faraday Cage effect (see below). 

In addition to the Faraday Cage effect, aerodynamic effects do not favor spraying inside a corner. Airflow considerations based on part geometry must also be taken into account to deliver the highly charged powder inside a corner or a channel, while not using so much air that the powder is prevented from depositing. 

Powder coatings have trouble penetrating deep depressions. The electric field lines do not penetrate into these tight areas and the charged powder can not penetrate and deposit there. This is observed in almost all ninety-degree comers and is commonly referred to as a Faraday Cage effect. While this effect can not be eliminated entirely, it is minimized by using triboelectric equipment. 

Another advantage is the heavy coating in one dip. A disadvantage of this method is the 3-mil minimum thickness required to form a continuous film. Another disadvantage is that inside comers have low film thickness owing to the well-known Faraday cage effect. 

The advantage of the electrostatic fluidized bed is that small products, such as electrical components, can be coated uniformly and quickly. The disadvantages are that the product size is limited, and inside comers have low film thicknesses owing to the well known Faraday cage effect. 

Fig. 2 Faraday cage effect in powder coating. Adapted from Ref 5...

Murrell J N, Stace A J and Dammel R 1978 Computer simulation of the cage effect in the photodissociation of iodine J. Chem. Soc. Faraday Trans. II 74 1532... 

Faraday Cage Faraday effect Faraday generator Faraday s law Faraday s Law Faraday s law... 

Placing the cell in a grounded metal cabinet (Faraday cage) will protect it effectively against direct influence of electric field changes. 

The effect is like that of a Faraday cage that confines the electron within a spherical surface. It is therefore no longer appropriate to formulate the wave function with inhnite boundary conditions, assuming tp(r0) —> 0, for r0 < oo, instead. 

The molecular beam filtered out electrons and small ions since no electrostatic focusing was used. Applied deflection voltage less than about 0.1 V had no effect on the current arriving at the Faraday cage, which indicates that ions smaller than about 300 100 amu were not in the beam. 

The electrodes and measuring cell assembly are placed into a Faraday cage to minimize electrostatic effects on the electrodes, and the titrants are injected with a 1-ml automatic burette at a flow rate of 20 /al min-1. For low-temperature measurements, the titrant is precooled before it is introduced into the measuring cell. 

ISEs it is common practice to use potential measuring instruments with input impedances >10 Cl to ensure that there is no error in the potential measurement. Most modern pH/mV meters constructed with field-effect transistor-type input amplifiers fulfill this requirement. However, as the electrode surface area becomes smaller, the resistance of the ISE increases dramatically. Thus, for microsized electrodes, specially designed amplifier circuits with even higher input impedances are required to obtain accurate intracellular ion values and to help eliminate noise. In many instance, the micro-type measurements must also be made within the confines of a Faraday cage to reduce noise further by shielding the electrodes finm environmental noise. In automated clinical chemistry analyzers, confinement of the electrodes within the outer metal cabinet of the instrument serves a similar purpose. 

In general, the mobile phase is the more important factor (impurities, bubbles, stationary phase particles, change in flow-rate), but rapid fluctuations of the ambient temperature may also play a part (if the detector is placed in a draughty location). Power supply disturbances such as thermostat switching pulses may also have an effect, in which case a low-frequency filter is recommended. Sometimes a home-made Faraday cage from aluminium foil may help. 

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