The purpose of this study was to evaluate mechanical properties of the orthodontic wires according to heat treatment environments and cooling methods. Four types of wires were heat-treated in air, argon and vacuum at 500◦C, for 6 min, and were then either cooled in the furnace or a water bath. Increases in microhardness, maximal strength, yield strength and Young’s modulus of the orthodontic wi...

In connection with future utilization of magnetite titanium ores deposited in Poland in the region of Suwałki the test were performed to get information regarding the influence of titan and vanadium admixtures on the quality of pig iron and the run of blast furnace process. As a blast furnace charge, there were used magnetite titanium concentrates similar to the ores deposited in the Suwałki re...

Physical vapour deposition (PVD) is used to grow millimetre-long Bi2Te3 sub-micron belts catalysed by TiO2 nanoparticles. The catalytic efficiency of TiO2 nanoparticles for the nanostructure growth is compared with the catalyst-free growth employing scanning electron microscopy. The catalyst-coated and catalyst-free substrates are arranged side-by-side, and overgrown at the same time, to assure...

this work presents the heat transfer characteristics of a new type of porous radiant air heater that operates on the basis of effective energy conversion method between flowing gas enthalpy and thermal radiation. at each layer, the gas and solid phases are considered in non-local thermal equilibrium, and combustion in the porous radiant burner is modeled by considering a non-uniform heat genera...

mixed convection is a fundamentally significant heat transfer mechanism that occurs in selection industrial and technological applications. in this study, first the laminar mixed convection inside rectangular enclosure with moving wall and aspect ratio=10 is modeled and then the results are compared with other investigate. after showing varity of results, the investigation is continued with tur...

rectangular waveguide (wr) is one of the earliest types of transmission lines. rectangular waveguide can be produced by hot extrusion process. in this paper, the hot extrusion process of cuzn5 rectangular waveguide was investigated by finite element method (fem). in addition, genetic algorithm method (ga) was used to optimize the die geometry and process conditions to achieve the lowest magnitu...

:the aim of this work is to investigate the influence of sodium oxide on properties of fresh and hardened paste of alkali-activated blast furnace slag from isfahan steel plant. the silica modulus (sio2/na2o) of activator was adjusted at 0.6 and a number of mixes were designed in such a way to contain different levels of sodium oxide including 1, 2, 3, 4, 5, and 6% by weight of dry slag. the mos...

A recently developed model was used to study the CO/CO2 ratio inside a burning pulverized coal particle, to better understand the effect of bulk gas composition on the equilibrium partial pressure of reduced metal species at the surface of ash inclusions. The motivation was to improve the ability to model submicrometer particle formation by ash vaporization, as a function of furnace conditions....

Effects of rapid heat transfer using a fluidized bed on the heat-treating response of Al-Si-Mg alloys (both unmodified and Sr modified) were investigated. The heating rate in the fluidized bed is greater than in conventional air convective furnaces. Particle size analyses of eutectic Si showed that the high heating rate during fluidized bed solution heat treatment causes faster fragmentation an...

By analyzing of the tube-type heating furnace features and process, the temperature heating of the furnace was unidirectional, large inertia, heavy lag and changeable, it is hard to build an exact mathematical model confirmed parameters. Applying traditional control theory and method is difficult to achieve perfect control effect. We studied the application of the fuzzy control in tubular furna...