Murphy, A. B.
A two-dimensional numerical model is used to investigate cataphoresis (demixing driven by electrical fields) in free-burning arcs in mixtures of argon with helium, hydrogen, nitrogen and oxygen at atmospheric pressure. The method of inclusion of electrical field effects in the combined diffusion coefficient treatment of diffusion and demixing is presented. Cataphoresis is found to lead to large increases in helium concentration near the anode in argon-helium arcs and smaller decreases in hydrogen concentration near the axis in argon-hydrogen arcs. There is no significant effect in argon-nitrogen and argon-oxygen arcs. The effects of cataphoresis on other arc properties are generally small and are significant only in argon-helium arcs.
Full Text Available The main aim of presented in this paper results is analysis of the most important factors in the company activity. The questionnaire test were carried among persons employed by the company, which mainstream is method of cataphoresis anti-corrosion coating. In the paper also validity of the Toyota roof elements were defined. Based on research as the most important factors of the company mission, indicated the quality factor.
Gielen, John W A M; Groot, Simon de; Dijk, Jan van; Mullen, Joost J A M van der
In a previous paper we had presented experimental results on mercury segregation due to cataphoresis in direct current operated low-pressure argon-mercury gas discharges. In this paper, we present our model to describe cataphoretic segregation in argon (or another noble gas)-mercury discharges. The model is based on the balance equations for mass and momentum and includes electrophoresis effects of electrons on mercury. Good agreement is found between the experimental results and model calculations. The model confirms our experimental observation that the mercury vapour pressure gradient depends on the local mercury vapour pressure. Furthermore, the model predicts the reversal of the direction of the transport of mercury under certain conditions (the phenomenon known as retrograde cataphoresis)
plrobe pulse by • ".__ _O’L " . - ;’ , a : , A_. , ,cT , HC , Ott aw-,’ Ont .- A 0.0 _ ;:: ... .- lst ,as usea to study ’."’ Jf]* - module. No rot...anode end is caused by an imbalance of the momenta transferred by the electrons and ions to the neutral particles ( electrophoresis ). A general transport...theory will be presented which incorporates both effects. An approximate analytic solution shows that cataphoresis dcminates electrophoresis at low
Research report of FY 1996 on development of new hydrogen energy demonstration technology. 2. Results in the extension period of FY 1996; 1996 nendo kenkyu hokokusho. Shinsuiso energy jissho gijutsu kaihatsu (1996 nendo kikan enchobun)
The purpose of this project is to clarify the possibility of new hydrogen energy as a future energy source. The new hydrogen energy is obtained from the excess heat generation phenomenon through the electrolysis of heavy water using palladium metal as an electrode. The excess heat measurements were conducted through the excess heat confirmation tests using a fuel cell-type electrolytic cell up to November 1997. As a result, it was found that the excess heat measured by the calibration method can not be measured by the flow calorimetric method. In order to investigate the possibility of systematic errors of the both methods, the sensitivity, accuracy and responsibility, and the conditions of the excess heat generation, research activities based on new facts from scientific information and fundamental research supporting projects have been mainly performed. Among these, were performed the excess heat measurement tests by the cataphoresis method, absorption tests by the high-pressure and high-temperature charging method, gas plasma loading, in-situ X-ray detection, and reactant detection tests using Au/Pd/PdO heterogeneous structural body. 5 refs., 59 figs., 9 tabs.
Gielen, John W A M; Groot, Simon de; Mullen, Joost J A M van der
Due to cataphoresis, axial segregation of mercury will occur when the gas discharge of a fluorescent lamp is operated by means of a direct current. A consequence of this is a non-uniform axial luminance distribution along the lamp. To determine the degree of axial mercury segregation experimentally, axial luminance distributions have been measured which are converted into axial mercury vapour pressure distributions by an appropriate calibration method. The mercury segregation has been investigated for variations in lamp tube radius (3.6-4.8 mm), argon buffer gas pressure (200-600 Pa) and lamp current (100-250 mA) at mercury vapour pressures set at the anode in the range from 0.2 to 9.0 Pa. From the experiments it has been concluded that the mercury vapour pressure gradient at any axial position for a certain lamp tube diameter, argon pressure and lamp current depends on the local mercury vapour pressure. This observation is in contrast to assumptions made in earlier modelling publications in which one mercury vapour pressure gradient is used for all axial positions. By applying a full factorial design, an empirical relation of the mercury segregation is found for any set of parameters inside the investigated parameter ranges
Maedler, L.; Pratsinis, S.E.
Bismuth oxide is used as additive in paints and in cataphoresis, and as substitute for lead oxide in glass or porcelain. The presence of a small amount of Bi 2 O 3 in calcined ZnO ceramics promotes non-linear current voltage characteristics that are used in varistor production. Also tin oxide based gas sensors for carbon monoxide, exhibit improved sensitivity and selectivity when doped with Bi 2 O 3 . Furthermore, the total oxidation of isobutene is enhanced on bismuth containing tin oxide catalysts. Bismuth oxide itself serves also as catalyst for conversion of propylene to 1,5 hexadiene and can be regenerated when supported on α-Al 2 O 3 . In electrolyte, varistor, sensor and catalyst applications high purity and small Bi 2 O 3 particles with controlled morphology are required. Especially in catalysts the available surface area (below 17 m 2 /g) of Bi 2 O 3 limits applications at the moment. Typically, Bi 2 O 3 is prepared by oxidation of bismuth metal at 750-800 deg C or by thermal decomposition of carbonates or by addition of alkali-metal hydroxides to a bismuth salt solution. High temperature synthesis of Bi 2 O 3 from precursor gases was proposed by Liu and Kleinschmit using the established Aerosil route of reacting chloride precursors in a hydrogen / air (or oxygen) flame, but the volatility of the starting materials poses the most severe limitation. Suzuki et al. prepared spherical bismuth oxide particles of about 26 nm in diameter by the ICP-method. Spraying an aqueous bismuth nitrate solution into a hot wall reactor resulted in Bi 2 O 3 particles of about 100 nm in diameter. Here, synthesis of bismuth oxide nanoparticles is investigated by flame spray pyrolysis (FSP) as flame technology is used for manufacture of oxide commodities and as such FSP has high potential for manufacture of oxide nanoparticles. The FSP process, in particular, has the ability to synthesize metal oxides and mixed metal oxides of high purity at high production rates and under