Spark lighting

A. The early work of Krassina and of Wilson and Noyes with an aluminum spark light source showed that polymer formation is an important process. Hydrogen and acetylene were formed with very low quantum yields. The possibility of the formation of biphenyl was considered, but the results were inconclusive. The gas-phase photolysis has been reexamined with the use of more modern techniques by Shindo and Lipsky and by Pitts et a/. - , all at 1849 A. Shindo and Lipsky have placed emphasis on the quantum yield of benzene disappearance. They find that is 0.25 at 1 torr and approaches unity on extra-... 

Any source of ignition should be strictly prohibited within your work area. Electrical connections need to be appropriate for working in a hydrogen environment and connectors should always be tightened where they will not move or be loose and cause a spark. Light and other types of switches should be rated for the hazard of the environment. Battery operated devices with switches such as flashlights can also be a hazard. 

Warneck has carried out an extensive series of experiments in which he used a pulsed nitrogen-spark light source to determine drift velocities, diffusion coefficients, and kinetic temperatures as well as reaction rates of ions in gases. These have been the only photoionization experiments in which a pulse technique has been effectively used in the study of ion-molecule reactions. The reactant ions were formed by repetitive light pulses of about 0.5-//sec average duration, which (in all cases except hydrogen) was sufficiently short to justify the approximation of instanta-... 

Liquid can evaporate quite some time before a flame or spark lights the vapour. If this happens in a... 

Kranz-Shardin camera, the spark lighting and 10 frame exposure time with... 

Beryllium is added to copper to produce an alloy with greatly increased wear resistance it is used for current-carrying springs and non-sparking safety tools. It is also used as a neutron moderator and reflector in nuclear reactors. Much magnesium is used to prepare light nieial allo>s. other uses include the extraction of titanium (p. 370) and in the removal of oxygen and sulphur from steels calcium finds a similar use. 

Vented risers should be provided on most cooling towers to release only light hydrocarbon leakage from the cooling water before the spray header. No ignition or source of spark should be within 30 m of the vented riser. 

The predorninant method for the analysis of alurninum-base alloys is spark source emission spectroscopy. SoHd metal samples are sparked direcdy, simultaneously eroding the metal surface, vaporizing the metal, and exciting the atomic vapor to emit light ia proportion to the amount of material present. Standard spark emission analytical techniques are described in ASTM ElOl, E607, E1251 and E716 (36). A wide variety of weU-characterized soHd reference materials are available from major aluminum producers for instmment caUbration. 

This is a transient discrete electric discharge which takes place between two conductors which are at different potentials, bridging the gap in the form of a single ionization channel (Plate 4). Based on light emission measurements of sparks with symmetrical electrode geometry, the energy is dissipated approximately uniformly along the channel. This is in contrast with asym-... 

Approximately 70 different elements are routinely determined using ICP-OES. Detection limits are typically in the sub-part-per-billion (sub-ppb) to 0.1 part-per-million (ppm) range. ICP-OES is most commonly used for bulk analysis of liquid samples or solids dissolved in liquids. Special sample introduction techniques, such as spark discharge or laser ablation, allow the analysis of surfaces or thin films. Each element emits a characteristic spectrum in the ultraviolet and visible region. The light intensity at one of the characteristic wavelengths is proportional to the concentration of that element in the sample. 

It then came to light that the handrails were covered with plastic and that anyone using them and wearing insulating footwear acquired an electric charge. When he touched the metal of the plant, he got a mild electric shock. The spark, of course, was not serious enough to cause any injury. But it was unpleasant. People therefore tended not to use the handrails. 

Water v. as being drained from a tank on another part of the plant. The v. ater flow was too great for the capacity of the drains, so the water backed up into the compound of small tanks, taking some light oil with it. This oil was ignited by welding sparks. 

---