Turbine blade tip durability analysis

An air-cooled turbine blade from an aircraft gas turbine engine chosen for its history of cracking was subjected to advanced analytical and life-prediction techniques. The utility of advanced structural analysis techniques and advanced life-prediction techniques in the life assessment of hot section components are verified. Three dimensional heat transfer and stress analyses were applied to the turbine blade mission cycle and the results were input into advanced life-prediction theories. Shortcut analytical techniques were developed. The proposed life-prediction theories are evaluated

Lightweight Ceramics for Aeroacoustic Applications

The use of a HTP (High Temperature Performance) ceramic foam for aeroacoustic applications is investigated. HTP ceramic foam is a composition of silica and alumina fibers developed by LMMS. This foam is a lightweight high-temperature fibrous bulk material with small pore size, ultra high porosity, and good strength. It can be used as a broadband noise absorber at both room and high temperature (up to 1800 F). The investigation included an acoustic assessment as well as material development, and environmental and structural evaluations. The results show that the HTP ceramic foam provides good broadband noise absorbing capability and adequate strength when incorporating the HTP ceramic foam system into a honeycomb sandwich structure. On the other hand, the material is sensitive to Skydrol and requires further improvements. Good progress has been made in the impedance model development. A relationship between HTP foam density, flow resistance, and tortuosity will be established in the near future. Additional effort is needed to investigate the coupling effects between face sheet and HTP foam material

Teacher Upgrading through Distance Education in a South African Context

In 1994, after the dismantling of Apartheid in South Africa, there were more than 85,000 teachers in the system who had no tertiary qualifications or were inadequately qualified. Most of these teachers lived in rural areas, and had no access to tertiary institutions. This situation required a unique approach to overcome the problems specific to the demographic and socio-economic circumstances of the country.The North-West University in South Africa took up the challenge and became involved in the huge task of upgrading the qualifications of these teachers by implementing a distance education programme. A flexi programme has been implemented by the establishment of thirty-two learning centres in locations throughout the country, which are accessible to these students. Full time lecturers and trained part time facilitators offer contact classes twice a month. Vacation schools provide additional learning opportunities. The recruitment and enrolment of students, distribution of study material and other administrative duties are supplied by supporting companies.Quality control for all these programmes is ensured by benchmarking against the programmes presented on the main campus i.e. B.Ed Hons., ACE and NPDE. Currently more than 17 000 teachers are enrolled in modules presented in the flexi mode and a passing rate of more than 70% attests to the success of the programme.</p

Effect of Cryogrinding on Chemical Stability of the Sparingly Water-Soluble Drug Furosemide

Purpose To investigate the effect of cryogrinding on chemical stability of the diuretic agent furosemide and its mixtures with selected excipients. Methods Furosemide was ground at liquid nitrogen temperature for 30, 60, 120 and 180 min. Mixtures of furosemide-PVP and furosemide-inulin (1:1) were milled under cryogenic conditions. Materials were analyzed by XRD, UPLC, MS and NMR. Results Upon increasing the milling time, a significant build-up of an unidentified impurity 1, probably the main degradation product, was noticed. Cogrinding of furosemide with PVP and inulin worsened chemical stabilization of the pharmaceutical. The main degradation product formed upon cryomilling was subsequently identified as 4-chloro-5-sulfamoylanthranilic acid (CSA). Based on some theoretical considerations involving specific milling conditions, the milling intensity and an expected specific milling dose have been calculated. Results indicate that cryogenic grinding is capable to initiate mechanically induced decomposition of furosemide.Conclusions Cryogenic grinding can activate and accelerate not only structural changes (solid state amorphization) but also chemical decomposition of pharmaceuticals. A cryogenic milling device should be considered as a chemical reactor, where under favourable conditions chemical reactions could be mechanically initiated

Knowledge of final-year medical students at the University of the Free State of hand hygiene as a basic infection control measure

Background: One of the main reasons for the spread of infection in the healthcare environment is inadequate hand hygiene. Poor knowledge of hand hygiene techniques leads to poor compliance. This study aimed to determine Free State University finalyear medical students’ knowledge of hand hygiene as a basic infection control measure. Methods: This was a cross-sectional study using self-administered anonymous questionnaires. The questions and memorandum were based on an extensive literature review with WHO documentation on the guidelines for hand hygiene in health care. Each participant received an envelope with an optical computer card, questionnaire and information document during a pre-arranged class. Participants recorded their answers on the card by shading in the squares corresponding to their responses.Results: The average score of the 107 participants was 46.8% (range 10.1–73.6%). Participants who felt that they had basic knowledge of hand hygiene (n = 32, 30.5%) had an average score of 47.9%. Participants with a self-reported knowledge level of more than basic but less than advanced (n = 56, 53.3%) had an average score of 44.9% while those who reported advanced knowledge (n = 17, 16.2%) had an average score of 50.8%. Three-quarters (n = 81, 77.1%) felt that their training was sufficient. Only 53.3% knew that the most important way to prevent the spread of infection is good hand hygiene. Only 10.5% of the students knew that hands should not be rinsed with water after using alcohol-based sanitisers.Conclusion: Medical students have a poor level of knowledge regarding hand hygiene as a basic measure of infection control