Alumina/water suspensions in the presence of PEO-PPO-PEO triblock copolymers

The aim of this study was to investigate the stability and dispersion behaviour of aqueous alumina suspensions in the presence of polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) type triblock copolymers. For this purpose alumina suspensions at various solids loadings were prepared using four different methods. These are: Method I: powder and water were stirred only; Method II: powder and water were stirred and ultrasonic treatment was applied; Method III: powder and water were stirred in the presence of block copolymers; Method IV: powder and water were stirred and ultrasonic treatment was applied in the presence of block copolymers. These suspensions were characterized by means of rheological measurements. Sedimentation and turbidity measurements were also conducted to support these results and to investigate the stability of these systems for longer times. Surface tension measurements were performed to investigate the adsorption behaviour of block copolymers onto alumina surface. It was found that the use of PEO-PPO-PEO type triblock copolymers improved the dispersion behaviour of aqueous alumina suspensions in the presence of ultrasonic treatment at low solids loadings. However their effect was not significant at high solids loadings and without ultrasonic treatment

Influence of dispersing agents on the solubility of perovskites in water

In this study, solubility behavior of lead magnesium niobate (PMN) powders in water was investigated in the presence of pure polyacrylic acid and polyacrylic acid/polyethylene oxide comb polymers. Experiments were performed by measuring the solubility of PMN in terms of the concentration of Pb+2 and Mg+2 ions in supernatant as a function of pH and dispersing agent dosage. The concentrations of the metal ions in supernatant were found to be affected by the dispersant concentration, stirring time and the suspension pH. Results revealed that both dispersing agents enhance the cation dissolution from PMN surface at pH 9 due to weak (reversible) adsorption and complexation of Pb+2 and Mg+2 by carboxylate groups. On the other hand, under acidic conditions cation dissolution from PMN is inhibited and this was attributed to the strong adsorption of dispersing agents onto the powder surface and formation of a dense polymer layer

Hydrodynamics of Conical Spouted Beds with High Density Particles

An extensive experimental investigation of conical spouted beds with high density particles were carried out by measuring bed pressure drop, particle velocity and solids hold-up in a 15 cm ID conical spouted bed at three different cone angles (30°, 45°, 60°) with Yttria-stabilized zirconia (YSZ) particles (ρp = 6050 kg/m3). The results show that the minimum external spouting velocity increases with cone angle, particle diameter and static bed height. The bed is characterized by two regions: upward moving particles with high slip in the spout and slowly downward moving particles at loosely packed conditions in the annulus

Retrospective analysis of Turkish AML registry database, on behalf of AML working group of Turkish society of hematology

Abstract Introduction: To investigate the demographics and treatment details of the acute myeloid leukemia (AML) patients who were diagnosed and followed up in Turkey. Methods: Patients who were recorded on the database of Turkish AML Registry project were included in this study retro- spectively if they were diagnosed before 1st of Jan 2022. Demographics, patient, and disease related parameters both at the time of diagnosis and at the follow up and treatment outcomes were presented

Factors Affecting The Drying Behavior Of Ceramic Films

Drying behavior of PMN films were investigated using a cantilever deflection based device and scanning probe microscope. Drying stress of the films was measured as a function of suspension composition. Results showed that hydroxypropyl methycellulose (HPMC) has some influence on the stress formation due to its effect on the surface tension of the suspension. On the other hand roughness measurements showed that HPMC has insignificant effect on the roughness of the films and roughness is mainly depended on the binder content of the suspensions

Investigation The Drying Behavior Of Ceramic Suspension Droplets

Drying is a major issue in wet processing ceramics. It has crucial effects on the final properties ceramics films especially produced by aqueous based tape casting. In this study structural evolution of ceramic suspension droplets were investigated during drying. Effect of binder concentration on the ring formation from droplets was tested. Results revealed that PMN:latex ratio have some influence on the particle migration and at high latex concentrations particle clusters were observed in the supersaturated region

Near Net Shape Fabrication Of Pmn Scaffolds

Solid free form fabrication techniques are commonly employed in near net shaping of ceramics especially in the manufacture of microelectronics. Lead magnesium niobate (PMN) is an important relaxor ferroelectric material with perovksite structure used in the production of these multilayer ceramic devices. In this study two dimensional PMN arrays and three dimensional periodic structures were produced by robocasting which is a direct writing technique. Aqueous colloidal gels have been formulated for use as ink in solid freeform fabrication process. Results showed that complex PMN shapes having rod size down to 100 pm can be successfully produced by robocasting process to be used in microelectronic applications