Fractionation of poultry litter for enhanced utilization

ABSTRACT A potential waste management system for the use of poultry litter was studied based upon the fractionation of litter. It was determined that the compositions of the litter by particle size varied both with the number of flocks that had been raised on the litter and the type of house. As the number of flocks raised on the litter increased from one to three flocks, the amount of fine material increased from 23 to 41%, while the concentration of the middle fraction decreased from 47 to 40%, and the coarse fraction decreased from 26 to 16%. The efficiency of retrieval of the fine fraction from the raw litter by either a vibrating screen separator or a rotary drum separator were found not to be significantly different. It was determined by chemical analysis that the P and K concentrations appeared to be distributed uniformly throughout the litter in each fraction while the N was nonuniformly distributed. The concentration of N was greatest in the fine fraction

Highly diffuse reflector

The invention relates an apparatus and method for forming a diffuse reflector. In one embodiment of the invention, a diffuse reflector is formed by exposing transmissive particles of a pre-determined purity to pressure and forming a material having desired diffuse reflective properties. The transmissive particles may further be thermally treated, such as by sintering, to form material having desired diffuse reflective properties. The treated transmissive particles may then be disposed in a vessel and define a cavity therein to form an integrated cavity diffuse reflector.U

Cueva de los Portales, nord du Michoacan (Mexique)

International audience"Excavations undertaken in the Cueva de los Portales rockshelter, Michoacan, Mexico, leads to the identification of several levels from the archaic period, dated between 5200 y 2000 BC through 7 radiocarbon samples. The four preceramic phases are La Garza (5200-4500 BC), Palomo (4500-3100 BC), Portales (3100-2500 BC) y Salto (approximately 2500-2000 BC). All of them reflect the settlement of hunters-gatherers, who did not seem to have practiced any kind of horticulture or proto-agriculture. The results of this study are briefly synthesized in this paper." (source éditeur)"Les fouilles réalisées dans l’abri Cueva de los Portales, dans le nord de l’état du Michoacan, Mexique, ont permis de dégager plusieurs niveaux remontant à l’époque précéramique placés sur l’échelle du temps entre 5200 et 2000 av. J.-C. par 7 dates radiocarbones. Quatre phases ont été identifiées : La Garza (5200-4500 av. J.-C.), Palomo (4500-3100 av. J.-C.), Portales (3100-2500 av. J.-C.) et Salto (approximativement 2500-2000 av. J.-C.). Toutes correspondent à des occupations par des groupes de chasseurs-cueilleurs qui ne pratiquaient pas l’agriculture. Les différents éléments caractéristiques de chaque phase sont décrits brièvement." (source éditeur

Highly diffuse reflector

The invention relates an apparatus and method for forming a diffuse reflector. In one embodiment of the invention, a diffuse reflector is formed by exposing transmissive particles of a pre-determined purity to pressure and forming a material having desired diffuse reflective properties. The transmissive particles may further be thermally treated, such as by sintering, to form material having desired diffuse reflective properties. The treated transmissive particles may then be disposed in a vessel and define a cavity therein to form an integrated cavity diffuse reflector.U