Interlocking nailing for fractures of the femur and tibia

In 132 patients, fractures of the lower limb (71 femoral and 61 tibial fractures) were treated using interlocking nailing (ILN) according to Grosse and Kempf during the period 1986-1989. Of these, 118 were followed up for a median of 19 months (range 9-32 months). Inpatient stay averaged 9 days regardless of the fracture. Consolidation was achieved in approximately 3 or 4 months from the operation in tibial and femoral fractures, respectively. Tibial fractures were technically more demanding than femoral ones, and their average operating time was significantly longer (73 min versus 51 min). Only one patient had a malunion in malrotation. The most serious complication was in a closed upper tibial fracture with traumatic rupture of the popliteal artery. Although the nailing was technically successful, an above-knee amputation had to be carried out. In only one case did the nail fail, and tibial plating had to be performed. Given the present degree of expertise, ILN for fractures of the long bones of the lower limb is a safe and relatively easy procedure to perform.     

Complete transformer model for electromagnetic transients

A complete, three phase transformer model for the calculation of electromagnetic transients is presented. The model consists of a set of state equations solved with the trapezoidal rule of integration in order to obtain an equivalent Norton circuit at the transformer terminals. Thus the transformer model can be easily interfaced with an electromagnetic transients program. Its main features are: (a) the basic elements for the winding model are the turns; (b) the complete model includes the losses due to eddy currents in the windings and in the iron core; and (c) the solution of the state equations is obtained in decoupled iterations. For validation, the frequency response of the model is compared with tests on several transformers. Applications to the calculation of transients are given for illustration     

A systematic transition to flexible manufacturing

The transition from basic automation to flexible manufacturing is an expensive and tedious procedure. It requires meticulous planning and almost clairvoyant forecasting to insure that the initial flexibility obtained is sufficient to allow growth and expansion in the future. This paper will suggest a systematic and methodological approach to achieve optimal flexibility and describe the present results of its application to an ongoing system transformation.

Conclusions based on existing levels of completion are presented along with identification of critical and non critical flexibility requirements. The considerations and steps taken are summarized in a procedural format which may then be applied to a wide variety of system transformations.     

Segmented force plate (SFP) software package for clinical use

A gait analysis system is described. It is designed for clinical use as well as research purposes. The system is simple to operate and can be used by non-computer specialist. The design philosophy is straightforward and allows for easy adaptation to other systems. Samples of the output are presented.     

Dental amalgam – the effect of the technology of alloy powder preparation on the corrosion behaviour and the release of mercury

Dental amalgams are based on a broad spectrum of materials differing in their chemical composition, metallurgical treatment, and in the way the initial alloys powders are prepared. In addition to their chemical composition, amalgams based on various powders differ in both their microstructure and the amount of mercury needed for preparation. All these facts may affect electrochemical processes occurring during their interaction with oral fluids, and also mercury release. While verifying the effect of the technology used for the preparation of the high‐copper ternary alloy powder on the properties of resulting amalgams, this study aimed at the mechanism of their interaction with a model saliva solution as well as mercury release was included. Measurements were done in a model saliva solution using standard electrochemical methods and exposition measurements. The interaction of individual types of amalgams with artificial saliva did not reveal any significant differences. The free corrosion potential of all these amalgams in an aerated solution settled in the range of values in which tin oxidation, resulting in a layer of insoluble corrosion producsts, turned out to be the dominant anodic process. The rate of mercury release was the lowest for amalgams based on a gas‐atomized alloy. The highest rate of mercury release, and also its dependence on time, was exhibited by lathe‐cut powder based amalgam. In addition to different volume fraction of the Ag‐Hg phase and the level of its tin alloying, this different behaviour may be explained by differences in the rate at which a layer of tin corrosion products acting as a barrier to mercury release is formed.