Numerical Simulation and Experiment on Magnetic Flux Leakage Inspection of Cracks in Steels
The magnetic flux leakage inspection method is widely use d in the detection of pipelines, storage tanks and other steel materials. Especially in c orrosion pits detection, it has become a matured technology. As cracks may exist in the steels which may lead to big hazards, its detection becomes very important. Meanwhile, the cracks evaluation by MFL inspection can be determined by many parameters, it has much difficulty t o implement due to its weaker signals compared with pits. In this research, the finit e element model for cracks’ MFL is established and corresponding method are carried out. Furthe rmore, parameters such as depth, width, angle of cracks and scanning direction are analyzed. Also, the experiments are done which show great reliability comparing with numerical s imulations. The results show that the cracks can not be detected when the scanning direction para llels with it. So the cross-scanning method is recommended for MFL inspection on cracks.
A comparative study of 3D and axisymmetric magnetizer assemblies used in magnetic flux leakage inspection of pipelines
Axisymmetric numerical codes are often used in modeling non-destructive testing phenomena, to approximate geometries and defects which are not truly axisymmetric in nature. This is especially true in cases where large computational resources are needed to model the exact geometry. However, there has been no study to confirm the nature and extent of errors introduced by an axisymmetric approximation. The gas pipeline industry makes use of bath axisymmetric and non-axisymmetric magnetizers for the magnetic flux leakage inspection of pipelines. The authors utilize this platform to perform a comparative analysis of axisymmetric and non-axisymmetric magnetizers from a design perspective and also study the differences in respective electromagnetic behavior.
Perceived job importance and job performance satisfaction of selected clinical nutrition management responsibilities.
A nationwide survey of clinical nutrition managers was conducted to assess perceived importance of selected job responsibilities and perceived performance satisfaction of those job responsibilities. A questionnaire was developed to achieve the study objectives, validated by an expert panel, and pilot-tested prior to data collection. All members of the American Dietetic Association's Clinical Nutrition Management dietetic practice group (N=1,668) were asked to rate the importance of selected job responsibilities and their satisfaction with those responsibilities using Likert-type scales with descriptions. Results revealed that clinical nutrition managers perceived all job responsibilities listed in the questionnaire to be important (ie, the mean score of each responsibility was >3.0 of a 4.0 scale). Respondents rated regulatory-related job responsibilities as most important and were most satisfied with their performance of these responsibilities. Following regulatory-related responsibilities, clinical nutrition managers perceived patient satisfaction and staff retention to be more important than other responsibilities. In general, clinical nutrition managers were more satisfied with their job performance for job responsibilities that they ranked as more important.