Gas-Trennung mit Membranen

Gas Separation with membranes . Gas separation with membranes has already been tested in numerous fields of application, e. g. uranium enrichment or H₂ separation. In many of these processes the mass transfer units, so-called permeators, have to be connected in tandem in order to achieve high concentrations. A most economical operating method provides for each case an optimization of the cascades with regard to the membrane materials, construction and design of module. By utilization of the concentration gradient along the membrane a new process development has been accomplished – the continuously operating membrane rectification unit. Investment and operating costs can be reduced considerably for a number of separating processes by combining a membrane rectification unit with a conventional recycling cascade. However, the new procedure requires that the specifications for the module construction, flow design, and membrane properties be reconsidered.     

Temperature effects in reflective surface-acoustic-wave delay lines

In addition to variation of delay time with temperature change, reflective surface-acoustic-wave delay lines may suffer signal-amplitude variation with temperature change. This problem occurs because of the anisotropy of the surface-wave velocity and the thermal expansion in the piezoelectric materials used for these devices. Experimental results are presented as well as appropriate design considerations for devices that must be operated at an elevated temperature.     

Labyrinthine anomalies in trisomy 13 mosaicism

The temporal bone histopathology of a 2-month-old male with a bilateral cleft palate, cleft lip and polydactylia due to trisomy 13 mosaicism was studied. Anomalies in the ear involved a partial absence of the superior semicircular canal, an abnormally wide lateral semicircular canal, underdeveloped cochlear coils, an abnormally broad modiolus, an undeveloped organ of Corti and an underdeveloped basilar membrane in the basal turn of the cochlea, an unusually wide cochlear aqueduct, and deformed stapedial crura.     

Neue analysenmethode zur quantitativen bestimmung von vinylacetat in äthylen-vinylacetat-copolymeren

A new method for quantitative determination of vinyl acetate in copolymers is described. It is based on the elimination of acetic acid in molten p-toluenesulfonic acid at 160°C. The released acetic acid is potentiometrically titrated in the presence of p-toluenesulfonic acid. The method is applicable to a content of vinyl acetate from 0 to 100% in the copolymers.