On the suitability of agricultural by-products for the manufacture of granular activated carbon

An investigation of several agricultural by-products revealed that their suitability for activated carbon production is not determined by general material-specific features (elemental composition) but by type-specific features. A coarse-cellular structure (as in wood), which is indicated by porosities of the raw materials higher than 35% is disadvantageous. A specific change in the properties of cokes (porosity, density, hardness) is possible by varying the conditions of pyrolysis. By rapid heating in the pyrolysis step, for instance, macroporous residues are produced. Temperature and burnoff have the greatest influence on the quality of the activated carbon during the activation step. Of the investigated materials, coconut shells yield granular activated carbon of the highest quality. The following order of suitability of raw materials for activated carbon production was established: coconut shells> peach stones> plum stones> hazelnut shells> walnut shells> cherry stones.     

Rudolf Hoesch 90 Jahre

Ohne Zusammenfassung     

Hypothermic vocalizations of rat pups (Rattus norvegicus) and direct maternal search behavior.

Emissions of ultrasonic vocalizations (USVs) by rat pups (Rattus norvegicus) during hypothermia have consequences for recovery and warming. The effects on dam behavior of USVs emitted by 3- to 11-day-old pups during hypothermia at rectal temperatures between 18 and 22°C was investigated Rat dams were tested in a Y maze with the home cage as a start box. Dams were given, in one condition, a choice between a hypothermic pup emitting USVs or a hypothermic, silent (anesthetized) pup and, in the other, a choice between 2 hypothermic, silent pups. Although differing in some acoustic properties from normal isolation calls, USVs emitted by hypothermic pups both elicited maternal search behavior and acted as directional cues for dams, in comparisons with control dams exposed only to silent pups. Thus USVs of pups recovering from extreme hypothermia have communicative as well as physiological significance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nanocrystalline hard coatings within the quasi-binary system TiN–TiB2

Ti–B–N films with a gradient in the chemical composition were deposited onto austenitic stainless steel sheets by means of unbalanced DC magnetron co-sputtering using a segmented TiN\Tib₂ target. Film microstructure was characterized by means of electron-probe microanalysis (EPMA), transmission electron microscopy (TEM), electron energy-loss spectroscopy (EELS), and X-ray diffraction (XRD) as well as glancing angle X-ray diffraction (GAXRD). The mechanical properties of the coatings were measured using a depth-sensing nanoindenter. The composition of the films was found to lie close to the quasi-binary section TiN–TiB₂ within the ternary system Ti–B–N. The grain size determined from TEM investigations range between 3 and 5 nm. Coatings consisted of a nanocrystalline fcc TiN phase (with boron atoms and oxygen impurities dissolved), and TiB₂, TiB and B₂O₃. Microstructure as well as chemical composition of the films were not influenced significantly by the deposition parameters used in this investigation. Contrary, the mechanical properties were strongly influenced varying the ion bombardment. Hardness values exceeding 50 GPa and elastic moduli close to 500 GPa were obtained.     

Physical metallurgy and magnetic measurements of SmCo5-SmCu5alloys

The magnetic properties of the hexagonal intermetallic compounds involving the rare-earth and3dtransition metals have been reported in the literature. These alloys look promising as fine-particle permanent magnets. A large number of samples in the system SmCo5-xCuxwere prepared by induction melting under a protective atmosphere, and annealed at various temperatures. An outstanding feature of these alloys is their high intrinsic coercive force. After annealing at low temperatures, they show coercive forces above 20 kOe and an energy product of about 8 × 10⁶G.Oe. The most important factors determining the coercive force appear to be the chemical composition, the cooling rate, the alignment of the SmCO5-rich phase, and the annealing treatment. Examination by electron microscopy and electron probe techniques suggests a spinodal decomposition of a supersaturated solid solution into two phases, one rich in SmCo5and the other rich in SmCu5.