ISDN Implementation Stategy of the Deutsche Bundespost--From the ISDN Pilot Project to Commercial Services

The first section of this paper defines the Deutsche Bundespost concept of ISDN, the services to be integrated, and the various ISDN components. The second and third parts of the paper cover the ISDN Pilot project and the offering of commercial ISDN services in the Federal Republic of Germany. The implementation strategy is briefly shown together with some outlook of the integration of broad-band services into ISDN. The last part describes strategic development toward an integrated services universal network, offering all kinds of telecommunication services including individual communication as well as broadcast services such as radio and TV program distribution.     

Embedded optical fiber sensors for materials evaluation

Optical fiber waveguides embedded within materials have been applied to the measurement of chemical changes, strain, and temperature inside materials. This paper reviews some of the research that has been performed in this area over the past 10 years and cites the theoretical and demonstrated performance of such sensors for material evaluation during its manufacturing, in service lifetime and degradation periods.     

Die mittlere Additionsdauer eines Paralleladdierwerks

Summary Let E _n be the average number of steps for the addition of two binary numbers of length n (where the addition is carried out by a parallel adder as defined by v. Neumann), and let L _n be the least integer which is not less than the logarithm of n (of base 2). The following inequality is shown: L _n – 1 < E _n < L _n + 1. E _n can be computed recursively. A table of some values of E _n is given in the appendix. We suppose that E _n [log₂ n] + 1/3 holds for large n.     

Isolation and characterization of a nitrile hydratase from a Rhodococcus sp.

A new nitrile hydratase producing strain of Rhodococcus has been found. A method for purification of the nitrile hydratase and a characterization of the enzyme is described. The hydratase is a 52-kdal protein consisting of two subunits of molecular weights, 26 and 23 kdal, respectively. The hydratase exhibits a broad substrate specificity. Aliphatic saturated or unsaturated nitriles, as well as aromatic nitriles, are substrates for the enzyme. Inhibition of the enzyme activity by amides and carboxylic acids was observed. The optimum pH of the hydratase is 7.5. The enzyme is rather unstable, even at room temperature. The enzyme may be applied for the production of acrylamide. For this application of the enzyme, the optimal temperature is about 4°C, where the enzyme exhibits a satisfactory activity and stability.