ROTATING ELECTROMAGNETIC FIELD FOR NDT INSPECTIONS
Reliable performance of a component or structure depends on its pre-service quality and in-service degradation under operating conditions. The importance of Non-Destructive Testing and Evaluation is ever increasing, above all in ensuring pre-service quality and monitoring in-service degradation, in order to avoid premature failure of the components/structures. There are many Non-Destructive Techniques based on various physical principles. In this work, our main objective is the characterization of anomalies such as defects, stresses and microstructural degradations in materials. Particularly, in this work we propose a Finite Element Method based approach for modelling a fast and accurate evaluation of defects in metallic materials able to easily detect defects, aside from the orientation. Within this framework, the paper proposes the application of a magnetic fleld rotating perpendicularly to the analysed specimen. We discuss a few case studies, starting from numerical simulations and flnally highlighting the importance of this approach in order to evaluate the structural integrity assessment.
Korrosionsinspektion im Flugzeugbau
The inspections required on an aircraft during its operational phase are determined largely by the materials and constructions used. Practical experience has shown that corrosion can generally not be prevented on metallic aircraft structures, even if the surface protection systems have been chosen with great care. Constructions and materials used on aircraft and the result types of corrosion are described and the inspection concept is explained on the basis of this. Finally, typical inspection tasks are presented and the measurement results obtained with different NDT methods are presented and discussed.
Coexistence of Virulence and Antibiotic Resistance Genes in Pasteurella multocida Isolated from Diseased Rabbits
Pasteurella multocida (P. multocida)is considered a predominant pathogenic bacterial agent causing respiratory manifestations (snuffles) in rabbits with considerable economic losses and unfavorable prognosis in Egypt. A few recent P. multocida strains exhibit resistance to the most commonly used antibiotics in the veterinary field. Therefore, the present study was carried out to investigate the prevalence of both virulence and antibiotic resistance genes among P. multocida isolated from diseased rabbits in Sharkia Governorate, Egypt. Only 10 out of 100 tested rabbits` nasal swabs were finally confirmed positive for P. multocida of serogroup A by polymerase chain reaction (PCR). Antibiotic susceptibility testing of the recovered isolates revealed that they were all multidrug resistant (MDR) with a predominance of resistance to amoxicillin, ampicillin, amoxicillin/clavulanic acid, neomycin and tetracycline (100% each), followed by kanamycin and streptomycin (90% each). All the recovered isolates were further subjected to PCR screening of some common virulence and antibiotic resistance genes of interest . With the exception of toxA gene, the other virulence associated genes (ptfA, Omp87 and nanB) were found among all the examined isolates. Totally, all MDR P. multocida isolates contained at least one antibiotic resistance gene with aphA1 being the most prevalent (100%), followed by ermX gene (40%). Antibiotic resistance genotyping demonstrated the presence of multiple antibiotic resistance genes among majority of the isolates (40%) with only one isolate harboring 4 genes encoding identical resistance phenotypes. Evidentially, all MDR P. multocida isolates possessed at least 3 virulence genes accompanied by the attendance of antibiotic resistance genes. These findings evidenced that rabbits are potential sources of pathogenic P. multocida strains harboring virulence and antibiotic resistance genes. Therefore, it is evident that there is an urgent need for the judicious use of antibiotics in rabbits` treatment systems to successfully mitigate the propagation of drug resistance across P. multocida species.