Design of a TMS320 C25 signal processor for use in a monopulse radar

Summary in English.Charts in pocket.Bibliography: leaf 65.The advent of better and faster digital signal processing chips has led to digital implementation of many functions that have previously only been possible using analogue techniques. One such field is monopulse radar where available processing time is limited strictly to the radar pulse repetition frequency. The aim of this thesis is to design a specific signal processor using a Texas Instruments TMS320 C25 processor. This design is intended for monopulse radar systems using low pulse repetition frequencies. Features typical to monopulse radar signal processing, have been described here as system requirements. From this description a system specification, which is in fact the functional design of the processor, has been developed. Prototype circuitry was then designed and built in order to test the feasibility of performing, within the required time, the functions outlined in the system specification. Following on from the results of the tests, design of the hardware commenced. The design was successfully completed and tested. Although the TMS320 C25 was not found to be the ideal processor for this application, it is capable of performing the task within the required time. Careful consideration was given to the software design. A trade off between easily maintainable, high level language software, and high speed assembler had to be made. The final product is written in c but with critical procedures implemented in in-line assembler. This thesis provides insight into the type of hardware and the level of signal processing required for one type of signal processor used in a low PRF monopulse system

Enzyme-induced Formation of ß-Lactoglobulin Fibrils by AspN Endoproteinase

This paper describes a low temperature, enzymatic route to induce fibrillar structures in a protein solution. The route comprises two steps. First, ß-lactoglobulin was hydrolyzed into peptides at pH 8 and 37°C with the enzyme AspN endoproteinase, which resulted in the formation of random aggregates. After hydrolysis, the pH was lowered to 2. As a result, long fibrillar aggregates were formed which was observed using transmission electron microscopy and Thioflavin T fluorescence measurements

Cadmium and cobalt in tea and coffee and their relationship to cardiovascular disease

Both cadmium and cobalt are known to cause hypertension and cardiac pathology. Coffee drinking, but not tea drinking, has recently been implicated in the latter. Various brands of teas and coffees were analysed for cadmium and cobalt in order to discover whether these elements might be responsible for the deleterious effects of coffee. Coffee infusions made from finely-ground coffee beans, coffee made from instant powders, one of pure coffee and 2 of coffee and chicory blends, and tea infusions, were analysed by atomic absorption spectrophotometry. The cadmium content of 5 teas, averaged, was found to be 0,0298 μg/g tea. That of 7 coffees was 0,03  μg/g coffee, the average of 3 different methods, each of which averaged 0,027, 0,018 and 0,045 μg/g coffee. Pure instant coffee powder had the highest cadmium content and bush tea the lowest. The cobalt content of coffee was found to be considerably higher than that of tea. The content of 5 teas, averaged, was 0,20 μg/g tea and that of 7 coffees was 0,93 μg/g coffee, the average of 3 different methods, each of which averaged 0,75, 0,89 and 1,14 μ/g coffee. The cobalt content of pure instant coffee powder was the highest and that of bush tea and one other commercial brand of tea, the lowest. In view of the fact that quantities of these elements ingested by even heavy coffee drinkers, form only a very small proportion of the total daily intake, no firm conclusions can be drawn about their toxicity from this source.S. Afr. Med. J., 48. 230 (1974)

Rate, characteristics, and factors associated with high emergency department utilization

Background: Patients with high emergency department (ED) utilization account for a disproportionate number of ED visits. The existing research on high ED utilization has raised doubts about the homogeneity of the frequent ED user. Attention to differences among the subgroups of frequent visitors (FV) and highly frequent visitors (HFV) is necessary in order to plan more effective interventions. In the Netherlands, the incidence of high ED utilization is unknown. The purpose of this study was to investigate if the well-documented international high ED utilization also exists in the Netherlands and if so, to characterize these patients. Therefore, we assessed the proportion of FV and HFV; compared age, sex, and visit outcomes between patients with high ED utilization and patients with single ED visits; and explored the factors associated with high ED utilization. Methods: A 1-year retrospective descriptive correlational study was performed in two Dutch EDs, using thresholds of 7 to 17 visits for frequent ED use, and greater than or equal to 18 visits for highly frequent ED use. Results: FV and HFV (together accounting for 0.5% of total ED patients) attended the ED 2,338 times (3.3% of the total number of ED visits). FV and HFV were equally likely to be male or female, were less likely to be self-referred, and they suffered from urgent complaints more often compared to patients with single visits. FV were significantly older than patients with single visits and more often admitted than patients with single visits. Several chief complaints were indicative for frequent and highly frequent ED use, such as shortness of breath and a psychiatric disorder. Conclusions: Based on this study, high ED utilization in the Netherlands seems to be less a problem than outlined in international literature. No major differences were found between FV and HFV, they presented with the same, often serious, problems. Our study supports the notion that most patients with high ED utilization visit the ED for significant medical problems. © 2014 van der Linden et al.; licensee Springer