High-temperature performance of ferritic steels in fireside corrosion regimes: temperature and deposits

The paper reports high temperature resistance of ferritic steels in fireside corrosion regime in terms of temperature and deposits aggressiveness. Four candidate power plant steels: 15Mo3, T22, T23 and T91 were exposed under simulated air-fired combustion environment for 1000 h. The tests were conducted at 600, 650 and 700 °C according to deposit-recoat test method. Post-exposed samples were examined via dimensional metrology (the main route to quantify metal loss), and mass change data were recorded to perform the study of kinetic behavior at elevated temperatures. Microstructural investigations using ESEM-EDX were performed in order to investigate corrosion degradation and thickness of the scales. The ranking of the steels from most to the least damage was 15Mo3 > T22 > T23 > T91 in all three temperatures. The highest rate of corrosion in all temperatures occurred under the screening deposit

The control characteristic shaping of fluid mass flow adjustment elements

W artykule przedstawiono koncepcję elementów nastawczych: zasuwy, przepustnicy oraz zaworu grzybkowego, które charakteryzują się dobrze założoną zależnością między strumieniem płynu a stopniem ich otwarcia. Przedstawiono ideę algorytmu obliczeń projektowych, w którym wykorzystano metodę charakterystyki odwrotnej, kryterium liniowości oraz uogólnioną, podstawową charakterystykę przepływową.Paper presents a concept of adjustment elements which is characterized by demanded relation between the fluid mass flow and the opening factor. A method suitable for design process is presented in which the method of inverse characteristic, linearization criteria and fluid mass flow characteristic are utilized

Effect of annealing on properties of carbonaceous materials. Part II: porosity and pore geometry

The pore structure of carbonaceous materials was studied using image analysis. The effect of annealing on the porosity and pore geometry of cokes, chars, and pyrolyzed coals (laboratory chars) was examined in the temperature range of 973 K to 1773 K (700 C to 1500 C). The porosity of chars and pyrolyzed coals significantly increased during annealing at temperatures below 1373 K (1100 C) due to volatile matter release. Further increasing of the annealing temperature from 1373 K to 1773 K (1100 C to 1500 C) caused marginal porosity evolution. The porosity of cokes was not affected by annealing at temperatures below 1573 K (1300 C) and slightly increased in the temperature range 1573 to 1773 K (1300 C to 1500 C). The increase in the porosity of chars and pyrolyzed coals during annealing at temperatures 1373 K to 1773 K (1100 C to 1500 C), and cokes at 1573 K to 1773 K (1300 C to 1500 C), was a result of reactions with oxides of their mineral phases. Annealing had a marginal effect on the pore shape (Feret ratio) of carbonaceous materials, but enlarged the pore size of chars and pyrolyzed coals and decreased their pore density

Survival of Lactobacillus reuteri RC-14 and Lactobacillus rhamnosus GR-1 in milk

The aim of this study was to examine the hydrophobicities of 23 urogenital, dairy, poultry, and American Type Culture Collection isolates of lactobacilli and to determine the effect on hydrophobicity of serially passaging the strains in liquid medium. To this end, strains were grown after isolation and identification and then serially passaged up to 20 times. Hydrophobicity was assessed through contact angle measurements on lawns of cells by using water, formamide, methylene iodide, 1-bromonaphthalene, and hexadecane as wetting agents and through measurement of their partitioning in a hexadecane-water system. The hydrophobicities of these strains varied widely, with Lactobacillus casei strains being predominantly hydrophilic and L. acidophilus strains being mostly hydrophobic. For some isolates, serial passaging was accompanied by a clear loss of hydrophobic surface properties, whereas for other strains, cultures became heterogeneous in that some cells had already lost their hydrophobic surface properties while others were still hydrophobic. Adhesion of this collection of lactobacilli to hexadecane droplets in microbial adhesion to hexadecane (MATH) tests was driven by their aversion to water rather than by their affinity for hexadecane, as concluded from the fact that hexadecane contact angles were zero for all strains. Furthermore, adhesion of the lactobacilli to hexadecane in MATH tests occurred only when the water contact angle on the cells was above 60°