An elastic-plastic stress analysis in a thermoplastic composite cantilever beam loaded uniformly

In this study an elastic-plastic stress analysis is carried out on a steel fiber reinforced thermoplastic composite cantilever beam loaded uniformly at the upper surface. An analytical solution is found satisfying both the governing differential equation in two dimensional case and boundary conditions. In this solution, the intensity of the uniform force is chosen small, therefore the transversely normal stress component is neglected in comparison with the other stress components. The thermoplastic matrix is reinforced unidirectional ly by steel fibers. The orientation angles of the fibers are chosen as 0 degrees, 30 degrees, 45 degrees, 60 degrees and 90 degrees. The plastic region begins first at the upper surface of the beam for 30 degrees and 45 degrees orientation angles. However, it starts earlier at the lower surface for 60 degrees orientation angle. The intensity of the normal residual stress component in the axial direction of the beam is maximum at the upper and/or lower surfaces in the beam. The intensity of the shear residual stress is maximum on or around the axial axis of the beam

Tribological evaluations of polyester composites considering three orientations of CSM glass fibres using BOR machine

[Abstract]: In the current work, the effects of chopped strand mat (CSM) glass fibre 450 g/m2 on tribo-properties of unsaturated polyester are evaluated. Experimental tests were performed by using Block on Ring (BOR) machine against polished stainless steel under dry contact condition. Three principle orientations of CSM glass fibre in the matrix were considered, i.e. namely Parallel (P-O), Anti-Parallel (AP-O) and Normal (N-O). Specific wear rate, friction coefficient and interface temperature were determined and presented as a function of applied load (30–100 N), and sliding distance (0–14 km) at two different sliding velocities (2.8 and 3.9 m/s). Scanning electron microscopy (SEM) was used to observe the damages features on the worn surfaces. The results showed that the orientations of CSM glass fibre significantly influenced the tribological performance of polyester composite. Better tribo performance were achieved when the polyester was reinforced with CSM glass fibre and tested at Parallel orientation. Moreover, specific wear rate and friction coefficient of polyester was reduced by 75%, and 55% at P-O of CGRP composite. The damage features were predominated by debonding of fibers, matrix deformation and polyester debris transfer

What should be the appropriate minimal duration for patient examination and evaluation in pulmonary outpatient clinics?

INTRODUCTION: Patient examinations performed in a limited time period may lead to impairment in patient and physician relationship, defective and erroneous diagnosis, inappropriate prescriptions, less common use of preventive medicine practices, poor patient satisfaction, and increased violent acts against health-care staff. OBJECTIVE: This study aimed to determine the appropriate minimal duration of patient examination in the pulmonary practice. METHODS: A total of 49 researchers from ten different study groups of the Turkish Thoracic Society participated in the study. The researchers were asked to examine patients in an almost ideal manner, without time constraint under available conditions. RESULTS: A total of 1680 patient examinations were reviewed. The mean duration of patient examination in ideal conditions was determined to be 20.4 +/- 9.6 min. Among all steps of patient examination, the longest time was spent for "taking medical history." The total time spent for patient examination was statistically significantly longer in the university hospitals than in the governmental hospitals and training and research hospitals (P < 0.001). Among different patient categories, the patients with a chronic disorder presenting for the first time and were referred from primary or secondary to tertiary care for further evaluation have required the longest time for patient examination. CONCLUSION: According to our study, the appropriate minimal duration for patient examination is 20 min. It has been observed that in university hospitals and in patients with chronic pulmonary diseases, this duration has been increased to above 25 min. The durations in clinical practice should be planned accordingly