Immobilisierte Enzyme – Kinetik,Wirkungsgrad und Anwendung

Immobilized enzymes – kinetics, efficiency, and applications. Immobilized enzymes represent an important class of catalysts. They are used in many industrial processes, some of which are economically significant. The introduction of other new processes is to be expected, and some examples are briefly described. Certain conditions have to be satisfied for their practical application. They can be summarized in a set of characteristic parameters or properties. The principal properties of a biocatalyst include its kinetics and its efficiency. Both of these are discussed at length. Possible catalyst designs permitting improvement of efficiency with mass transfer limitation are described.     

Applying a formal analysis technique to the CCITT X.509 strong two-way authentication protocol

In the quest for open systems, standardization of security mechanisms, framework, and protocols are becoming increasingly important. This puts high demands on the correctness of the standards. In this paper we use a formal logic-based approach to protocol analysis introduced by Burrows et al. [1]. We extend this logic to deal with protocols using public key cryptography, and with the notion of duration to capture some time-related aspects. The extended logic is used to analyse an important CCITT standard, the X.509 Authentication Framework. We conclude that protocol analysis can benefit from the use of the notation and that it highlights important aspects of the protocol analysed. Some aspects of the formalism need further study.This research was sponsored by the Royal Norwegian Council for Scientific and Industrial Research under Grant IT 0333.22222, and was performed while K. Gaarder was at Alcatel STK Research Centre.     

Important Parameters for the Manufacture of Slow-Release Matrix Pellets With an Aqueous Dispersion of Quaternary Poly(meth)acrylates in the Rotary Fluidized Bed

ABSTRACT

The manufacture of slow-release matrix pellets with an aqueous dispersion of quaternary poly(meth)acrylates was investigated in the rotary fluidized bed. By considering the moisture content of the fluidized bed to be the key process parameter, it was measured on-line throughout the whole manufacturing process. A specially designed sampling device opened new ways to apply NIR spectrometry in laboratory scale processes. It was shown that reproducibly improved pellet properties can be achieved by reproducing the moisture content of the (rotary) fluidized bed. Moisture plateaus proved to be a suitable way to optimize the sphericity of the pellets. Premoisturizing was found to be a very effective tool to achieve slow-release dissolution of the model drug theophylline.     

Problems and Benefits of Requirements Gathering With Focus Groups: A Case Study

Focus group interviews are considered as a rather weak, nonquantitative method of assessing user needs, ideas, and reactions in an early stage of the interface design process (Nielsen, 1993). Given this fact, it is relevant to reflect the practical use of focus groups step by step to determine their real strengths and limitations. In this article, we share our experience of planning, running, and analyzing focus groups within the design process of a home automation system. We describe the pre- and postwork in detail so that the pros and cons of gathering requirements with focus groups become apparent.