Preparation and characterization of NextelTM 720/ alumina ceramic composites via the prepreg process

In this work, the continuous Nextel™ 720 fiber reinforced alumina ceramic matrix composites (CMCs) were prepared by the prepreg process. The alumina matrix derived from aqueous slurry, which consisted of organic glue, alumina sol, nanometer alumina powder and micrometer alumina powder. This combination endowed the ceramic matrix composite with the prepreg processing capability, making the low-cost fabrication of complex shape components possible. The ratio of different alumina sources in aqueous slurry was optimized to offer good sintering activity, high thermal resistance, and excellent mechanical properties simultaneously. Furthermore, the preceramic polymer of mullite was used to strengthen the ceramic matrix through multiple impregnation process. The final CMC sample achieved a high flexural strength of 255 MPa and a good high-temperature stability. The maximum flexural strength of the CMC sample still remained 85% after heat-treatment at 1100 ℃ for 24 h.

Investigating the Process of Producing Composite Hydrogel Particle Slurry

The paper presents comprehensive investigation results concerning obtaining a composite hydrogel material in the form of an aqueous slurry. We considered the issue of grinding hydrogel in water so as to obtain an aqueous slurry of hydrogel particles featuring the desired particle size distribution. We selected polyacrylamide to be the composite hydrogel material and used an anti-Stokes phosphor as a filler. We describe a multi-stage method for producing hydrogel, a coarse grinding process for hydrogel blocks, and a fine grinding technology employing an immersion disperser. We obtained slurries featuring a narrow particle size distribution (160--1000 µm). We provide data on investigating how the manufacturing process parameters and modal parameters of the equipment used affect the particle size distribution in the resulting hydrogel material. We propose a technology for producing composite hydrogel particle slurry in a single process cycle

Assessing Performance of Cattle Dung and Waste Cooked Foods in Producing Biogas as Single Substrate and Mixed Substrates in Kampala Uganda

Biogas is anaerobic degradation product formed from aqueous slurry of organic waste in a digester. It can be produced from cattle dung, (cd)chicken droppings, decaying leaves, kitchen waste foods, (kwf), sewage sludge, slaughter house, goat, pig or sheep manure, Aqueous slurry of 200 g/L of mixed or single substrate of cattle dung or/and kitchen waste evolved up to 400mL of biogas at ambient temperatures. The rate of gas evolution reached 5 mL/day on the 15th day using 25 % cd mixed slurry. The overall rates of degradation attained in the mixtures were 1.42 + 0.26 mL/g for cd; 1.58+0.33 mL/g for kwf; 1.78+ 0.38 mL/g for 75 % cd mixed substrate; 1.78+ 0.29 mL/g for 50 % cd mixed substrate; 1.92+ 0.21 mL/g for 25 % cd mixed substrate slurries in the 200 g/L load. The comparative rate of biogas formation ranged from1.25 to 1.35 which was in agreement with the range published in literature of 0.8 to 5.5. Biogas can be synthesized efficiently at ambient temperature in Kampala as was done at mesophilic temperatures elsewhere. However, it may be necessary to attempt producing biogas at different pH and temperatures as well as using other substrates and inoculums.