Features of glow discharge ignition through a small hole in the hollow cathode of a large volume

The influence of the size of a cathode gap on the initiation of the effect of a hollow cathode in a glow discharge system with an extended hollow cathode in the forevacuum pressure range is shown. It was found that the threshold current for the transition of the discharge to the burning mode with a hollow cathode is determined by the ratio of the longitudinal and transverse dimensions of the cathode slit. With a decrease in the width of the slot, the threshold current increases disproportionately; at the same time, with an increase in the length of the slot, this current sharply decreases.

Impact of Grinding Technology on Final Properties of Portland Cement

Portland cement got his name derived from the appearance of concrete that resembles sandstone located near city of Portland in England. In 1824, John Aspdin was granted a patent for the production of Portland cement.In the past, energy and economic demands on production of cement were lower than they are today. Production was characterized by a slower burning mode and coarser grinding. Product produced this way were reaching lower compressive strength.Currently there are several companies producing Portland cement. Main ones in Czech Republic are Holcim, Heidelbergcement group and Lafarge Cement a.s. Their production methods are very similar. The differences are mostly in the possibility of using local raw materials with different chemical composition and the technical equipment of factories. In the production, the main emphasis is on reducing energy and financial cost.One way to save energy and money is to use mechanical-chemical activation when grinding Portland clinker.

Laboratory Burning of Anhydrite from Phosphogypsum

The objective of this work is a research in the sector of preparation of anhydrite II based sulphate binder made from secondary raw material resources applicable in industry specialised in production of mortar mixtures. In particular it was a laboratory burnout of anhydrite II from phosphogypsum, which is formed during production of phosphoric acid. The selection of burning mode was done upon the results [1]. The selected burning mode influence on mineralogical composition of formed anhydrite was monitored with subsequent setting of basic technological properties and monitoring of hydration process course.

Electrode configurations and non-uniform dielectric barrier discharge properties

Interesting types of AC discharges in ambient air at atmospheric pressure for the generation of non-thermal plasma at/on dielectric surfaces were investigated. Pin-to-plane dielectric barrier discharge (PTP-DBD) was sustained in the electrode configurations combining electrode components of both corona and DBD - metallic pins, or triangle spikes electrode, situated single- or double-in-line and metallic plate electrode covered with a dielectric barrier. It was investigated experimentally and theoretically the burning mode of a PTP-DBD in ambient air at atmospheric pressure. The PTP-DBD behavior with single- or double-in-line spikes high voltage electrode was discussed. The PTP-DBD is a new DBD-based discharge. .