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A La0.67Ca0.26Sr0.07Mn1.05O3 (LCSM) perovskite was prepared for the first time as a ceramic monolithic regenerator used in a regenerative magnetic refrigeration device. The parameters influencing the extrusion process and the performance of the regenerator, such as the nature of the monolith paste and the influence of the sintering on the adiabatic temperature change, were investigated. Comparisons between the extruded monolithic structure before and after the sintering showed that an increase of the adiabatic temperature change was seen after the sintering. Furthermore, calculations show that the performance of the monolithic structure is potentially superior to a parallel plate regenerator, indicating the potential cost and structural benefit of using such structure, i.e. a mechanically stable ceramic thin wall structure, which can be produced in one processing step.

Chronic myeloid leukemia (CML) is a clonal myeloproliferative disorder of the hematopoietic stem cell that is exceptionally rare in the first five years of life, particularly as a secondary malignancy. This report describes a case of secondary CML in a four-year-old female occurring after AML treatment. Interestingly, CML developed while on immunosuppression for a heart transplant due to anthracycline-induced cardiomyopathy.

A new way of producing rigid or semi-rigid foams from vital wheat gluten using a freeze-drying process is reported. Water/gluten-based mixtures were frozen and freeze-dried. Different foam structur ...

Electron microscopy characterization across the cathode-electrolyte interface of two different types of intermediate temperature solid oxide fuel cells (IT-SOFC) is performed to understand the origin of the cell performance disparity. One IT-SOFC cell had a sprayed-cosintered Ce(0.90)Gd(0.01)O(1.95) (CGO10) barrier layer, the other had a barrier layer deposited by pulsed laser deposition (PLD) CGO10. Scanning electron microscopy, transmission electron microscopy (TEM), and electron backscattered diffraction (EBSD) investigations conclude that the major source of the cell performance difference is attributed to CGO-YSZ interdiffusion in the sprayed-cosintered barrier layer. From TEM and EBSD work, a dense CGO10 PLD layer is found to be deposited epitaxially on the 8YSZ electrolyte substrate-permitting a small amount of SrZrO(3) formation and minimizing CGO-YSZ interdiffusion.

International audience; In the present work, 12-layered electrochemical reactors (comprising 5 cells) with a novel configuration including supporting layer lanthanum strontium manganate (LSM)-yttria stabilized zirconia (YSZ), electrode layer LSM-gadolinia-doped cerium oxide (CGO), and electrolyte layer CGO, were fabricated via the processes of slurry preparation, tape casting and lamination, and sintering. The parameters of porosity, pore size, pore size distribution, shrinkage, flow rate of the sintered reactors, and the electrical conductivities of the supporting layer and the electrode in the sintered reactors were characterized. The effect of sintering temperature on microstructures and properties of the sintered samples was discussed, and 1250 oC was determined as the appropriate sintering temperature for reactor production based on the performance requirements for applications. Using the present ceramic processing route, porous, flat, and crack-free electrochemical reactors were successfully achieved. The produced electrochemical reactors have the potential application in the removal of NOx and soot particles emitted from the diesel engines.

Deposition of La0.85Sr0.15MnO3 (LSM) films from suspensions using a magnetic field was found to be a cheap and quick technique. Ninety weight percent of the particles present in the suspensions were deposited within the first minute of the deposition, and the thickness of the film varied linearly with the concentration of the suspension. Deposition phenomena were explained by modeling the magnetic flux in the deposition cell. Particles aligned with the flux lines, forming chains of LSM particles that, upon sintering, resulted in the formation of porous films with long chains of LSM grains.

Al 2 O 3 powders have been successfully dispersed in ethanol by varying the suspension acidity. An operational pH (O.pH) was defined to measure the acidity of these ethanol-based suspensions. The isoelectric point of Al 2 O 3 in ethanol was at an O.pH of 8. According to Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, suspensions between an O.pH of 3.5-10.5 possessed only attractive inter-particle potential. Suspensions below 3.5 had high ζ potential, fine particle size, and were Newtonian. However, suspensions at high pH were shear thinning and consisted of agglomerates, despite their high ζ potential. The use of citric acid as a dispersant has also been investigated. At an O.pH of 3, optimum additions of citric acid between 0.6 and 1.0 wt% decreased the particle size, resulted in repulsive inter-particle potentials and increased the solid loading capacity to 15 vol% from 2 vol% while maintaining Newtonian behavior and similar viscosity to suspensions at O.pH 2. Addition of citric acid created agglomerated suspensions that were negatively charged at O.pH 10.5 (obtained by adding NH 4 OH), but positively charged suspensions at O.pH 13.6 (obtained by adding tetramethylammonium hydroxide).

Crystal structure and thermal properties of La 1-x Sr x FeO 3-δ (x = 0, 0.1, 0.3, 0.4, 0.5, and 0.75) have been studied by high-temperature X-ray diffraction and thermal analysis in air and nitrogen (p(O 2 ) 10 -3 atm) atmosphere. The first-order phase transition from orthorhombic-to-rhombohedral La 1-x -Sr x FeO 3-δ (x = 0, 0.1) was strongly shifted to lower temperatures with increasing Sr content. The phase-transition temperature was observed significantly lower in polycrystalline ceramics compared with fine powders. The temperature depression of the phase transition in the ceramics was qualitatively explained by stresses induced both by the anisotropic thermal expansion of LaFeO3 and the observed volume contraction of the phase transition. Rhombohedral La 1-x Sr x -FeO 3-δ (x = 0.3, 0.4, 0.5) were observed to transform to the cubic perovskite structure during heating. The second-order phase-transition temperature decreased with increasing Sr content and decreasing partial pressure of oxygen. On the basis of the present findings, a pseudobinary phase diagram of the LaFeO 3 -SrFeO 3-δ system is presented. Finally, a severely nonlinear thermal expansion was observed for the Sr-rich materials at high temperature. The high thermal expansion in this region is due to a chemical expansion resulting from a reduction of the valence state of Fe.

Shrinkage behavior and crack formation during firing have been investigated for Al2O3/Ce-TZP composites that have been fabricated by colloidal rolling and folding. These composites show improved sinterability and sinter isotropically after repeated rolling. Interface instability in rolling creates corrugated interfaces with large layer waviness; therefore, rolling can substantially alleviate the in-plane sintering constraints, which leads to improved sinterability. A loss of sintering anisotropy also is observed and is directly correlated to the microstructure instability, which is coincident with the laminate‐cellular transition. Sintering cracks during heating and thermal cracks during cooling both are limited to the thick Ce-TZP layers in the composites. The critical layer thickness and the normalized crack spacing of the thermal cracks follow the predicted behavior of elasticity theory. Thus, crack-free, high-density Al 2O3/Ce-TZP composites with either a laminate or cellular microstructure can be obtained, with a layer thickness of 4‐60 µm, via pressureless sintering.

Reaction hot-pressing behavior of {alpha}-Si{sub 3}N{sub 4}, Al{sub 2}O{sub 3}, AlN, and M{sub 2}O{sub z} powder mixtures (M = Li, Mg, Ca, Y, Nd, Sm, Gd, and Yb) forming {alpha}{prime}-SiAlON has been studied. Five characteristic temperatures are found to control the densification behavior of these materials. The densification proceeded in three major stages. The first two stages were formation of ternary oxide eutectic and wetting of majority nitride powder. The third stage involved dissolution/melting of intermediate phase. Variation from this behavior sometimes occurs due to localization of wetting liquid at AlN, extremely high melting/dissolution temperature of Mg{sub 2}Al{sub 4}-Si{sub 5}O{sub 18} and Nd and Sm melilite, and secondary precipitation Dy-{alpha}{prime}-SiAlON. The dominant densification mechanism was found to be massive particle rearrangement, irrespective of the wetting and dissolution/melting behavior. The efficiency of this mechanism is mostly affected by the amount of available liquid and less by its viscosity. Fully dense, single-phase ceramics were obtained in all cases exceed Mg when hot-pressed at a constant heating rate to 1,750 C, and considerably lower temperatures for Li, Ca, Gd, Dy, Er, and Yb-SiAlON when held isothermally.

Phase development during reaction hot pressing of {alpha}-Si{sub 3}N{sub 4}, AlN, Al{sub 2}O{sub 3}, and M{sub 2}O{sub z} powder mixtures (M = Li, Mg, Ca, Y, Nd, Sm, Gd, Dy, Er, and Yb) forming {alpha}{prime}-SiAlON has been studied. The wetting behavior of the ternary eutectic melt of M{sub 2}O{sub z}-Al{sub 2}O{sub 3}-SiO{sub 2} was found to control the reaction sequence during hot pressing. Li, Ca, Mg, Nd. Sm, and Gd were found to preferentially wet and react with Si{sub 3}N{sub 4} first, whereas Dy, Er, and Yb preferentially wetted and reacted with AlN first. The intermediate phases are Si rich in the former and Al rich in the latter case. Pearson`s principle of acid-base theory, which predicts decreasing basicity of oxides of Li, Ca, Mg, Nd, Gd. Sm, Dy, Er, and Yb and decreasing acidity of oxides of Si and Al, is used to understand these reactions.