Directional heat transfer was investigated by temperature measurements in the casting and in the mould using thermocouples. Measurements were performed in operating conditions during pouring, ...solidification, and cooling of the casting. Total measurement time was 35,5 hours. After cutting, specimens were extracted for me-tallographic and hardness testing. Test results provided confirmation of directional heat transfer (directional cooling) that would ensure acquirement of a desired casting structure and mechanical properties.
Quality heating of the steel charge to be rolled into seamless tubes in the rotating-hearth furnace requires continuous operation of the pilger mill. Interruption of the charging schedule leads to ...impaired charge heating process. Prolonged heating time causes a rise in the charge temperature above the limit values, and that in turn brings to a larger quantity of scale formed on the charge surface. Final result is loss of metal and overheating of the charge accompanied by increased fuel consumption and lower furnace productivity.
The heating operation of the rotating-hearth furnace involving semi-finished steel products was analysed, and specific heat consumption was determined as a function of furnace productivity. The aim ...was to find out how a change in productivity, which is not accompanied by a modification of the thermal regime, can affect the heating quality and surface oxidation of products.
A microwave gas chromatography (GC) column oven is engineered to generate a uniform microwave field around an open tubular column with the elimination of cold spots, which are common in a domestic ...microwave oven. Short cool-down time in microwave heating makes it possible to employ negative temperature programming for the enhanced separation of compounds during the process. The feasibility of negative temperature programming in microwave GC is investigated for the analysis and quantitation of four different pairs of nonvolatile and volatile compounds. The influence of intermediate column cooling rate, holding time in the cooling ramp, and reheating rate after the cooling ramp for enhanced resolution are investigated. The results obtained from negative temperature programming are compared with those from positive temperature programming. Negative temperature programming affords greater resolution of some critical pairs of analytes.
Taking statistically-documentary basis as a starting point and applying adequate mathematical methods, numerical functional relations between total annual production and single production expenses, ...i.e. average total production expenses are defined. Functional relation between both of them with different number of employees compared to the average number of employees in the analysed period of time is also defined.
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