Creep resisting steels, nanoparticles, interparticles matrix stresses, mobile dislocations motion and creep rate

Development of improved equation for better accuracy of calculation of stationary creep rate of creep resisting steels. Effect of acting stress components in particles disjunction matrix. Effect of increase of number of ferrite lattice vacancies

Influence of testing rate on Lüders band propagation in niobium microalloyed steel

Using thermal imaging camera during tensile testing of low carbon and Nb microalloyed steel influence of testing rate on start of plastic deformation was investigated. The results showed that the onset of plastic flow is significantly different in Nb steel. When testing Nb steel, above the yield point (Reh), Lüders bands formed and no change of temperature was recorded by increase of sample stretching force. Strain rate affects the propagation velocity of Lüders bands through the deformation zone

The Influence of the Temperature Factor on Deformability of the Plastic Medium

Using the solution of a closed problem of the theory of plasticity some analytic expressions were obtained for determination of the strain parameters of zone of deformation in view of the temperature factor

Effects of preferred grain orientation on the on lüders bands appearance

In this paper, the influence of preferential grain orientation was examined. Parallel tests were conducted on the samples from the same steel strip, taken in the direction and perpendicular to the direction of rolling the strip. Steel strip has a homogeneous fine-grained ferrite-pearlite microstructure. Using the methods of thermography it has been found that at the beginning of the plastic flow Lüders bands occur, pointing to the fact that the preferential grain orientation, in the case of steel with the fine-grained ferrite-pearlite microstructure, has no effect on the appearance of the Lüders bands

Lüders bands at the beginning of the plastic flow of materials

Intensive research into inhomogeneous deformations at the beginning of the plastic flow on different metal materials has been carried out during the last few years. Lüders bands are detected using methods of static tensile testing, thermography and visioplasticity with digital image correlation. This paper is a review of insights into the mechanism of formation and parameters influencing the occurrence and propagation of Lüders bands. Current knowledge indicates that there is not a full explanation of the cause of the Lüders bands formation. There are also certain differences in the way some parameters influence the occurrence of Lüders bands, primarily in different materials. Therefore, modern methods are used to explain the formation of Lüders bands

Knowledge, attitudes and practices around health research: the perspective of physicians-in-training in Pakistan

<p>Abstract</p> <p>Background</p> <p>Health research training is an essential component of medical education and a vital exercise to help develop physician research skills. This study was carried out to assess the level of knowledge, attitudes and practices towards research amongst a group of Post Graduate Medical Trainees (PGMTs') at Aga Khan University (AKU), Pakistan.</p> <p>Methods</p> <p>A cross sectional health research survey was carried out on all PGMTs' at AKU Pakistan. AKU is a tertiary care health facility which offers residency in 28 specialties and fellowship in 16 programs. Knowledge, attitudes and practices related to health research were assessed using a pretested, structured and validated questionnaire. Health research related practices of the residents were examined using questions graded on Likert scale.</p> <p>Results</p> <p>Mean percentage score ± SD on the knowledge scale was 36.9% ± 20.2 and 47.19% ± 25.18 on the attitude scale. Of 104(55.6%) who had previously participated in research 28(26.9%) had been involved in basic science research only, 62(59.6%) in clinical research and 14(13.5%) had participated in both clinical and basic science research projects. 88(47.1%) planned to pursue a future research career. Those who planned to pursue a future research career had more positive health research attitudes p < 0.001. Limited time (45%), poor research infrastructure (20%) and inadequate research funding opportunities (20%) were the major hurdles faced by PGMTs' to pursue research.</p> <p>Conclusion</p> <p>PGMTs' demonstrate inadequate knowledge, while they have moderate attitudes towards health research. Residency training and research facilities at the institution need to undergo major transformation in order to encourage meaningful research by resident trainees.</p

Knowledge and attitudes about health research amongst a group of Pakistani medical students

Background Health research training is an important part of medical education. This study was conducted to assess the level of knowledge and attitudes regarding health research in a group of Pakistani medical students at Aga Khan University, Karachi. Methods It was a cross-sectional pilot study conducted among a group of Pakistani medical students. Through stratified random sampling, a pre-tested, structured and validated questionnaire was administered to 220 medical students. Knowledge and attitudes were recorded on a scale (graduated in percentages). Results Mean scores of students were 49.0% on knowledge scale and 53.7% on attitude scale. Both knowledge and attitudes improved significantly with increasing years of study in medical college [Regression coefficient 4.10 (p-value; 0.019) and 6.67 (p-value; \u3c 0.001) for knowledge and attitudes, respectively]. Conclusion Medical students demonstrate moderate level of knowledge and attitude towards health research. Intensive training in this regard is associated with significant improvement in knowledge and attitudes of students towards health research

Geokinematics of Central Europe: New insights from the CERGOP-2/Environment Project

The Central European Geodynamics Project CERGOP/2, funded by the European Union from 2003to 2006 under the 5th Framework Programme, benefited from repeated measurements of thecoordinates of epoch and permanent GPS stations of the Central European GPS Reference Network(CEGRN), starting in 1994. Here we report on the results of the systematic processing of availabledata up to 2005. The analysis has yielded velocities for some 60 sites, covering a variety of CentralEuropean tectonic provinces, from the Adria indenter to the Tauern window, the Dinarides, thePannonian Basin, the Vrancea seismic zone and the Carpathian Mountains. The estimated velocitiesdefine kinematical patterns which outline, with varying spatial resolution depending on the stationdensity and history, the present day surface kinematics in Central Europe. Horizontal velocities areanalyzed after removal from the ITRF2000 estimated velocities of a rigid rotation accounting forthe mean motion of Europe: a ~2.3 mm/yr north-south oriented convergence rate between Adria andthe Southern Alps that can be considered to be the present day velocity of the Adria indenterrelative to the European foreland. An eastward extrusion zone initiates at the Tauern Window. Thelateral eastward flow towards the Pannonian Basin exhibits a gentle gradient from 1-1.5 mm/yrimmediately east of the Tauern Window to zero in the Pannonian Basin. This kinematic continuityimplies that the Pannonian plate fragment recently suggested by seismic data does not require aspecific Eulerian pole. On the southeastern boundary of the Adria microplate, we report a velocitydrop from 4-4.5 mm/yr motion near Matera to ~1 mm/yr north of the Dinarides, in the southwesternpart of the Pannonian Basin. A positive velocity gradient as one moves south from West Ukraineacross Rumania and Bulgaria is estimated to be 2 mm/yr on a scale of 600-800 km, as if the crustwere dragged by the counterclockwise rotation along the North Anatolian Fault Zone. This regimeapparently does not interfere with the Vrancea seismic zone: earthquakes there are sufficiently deep(&gt; 100 km) that the brittle deformation at depth can be considered as decoupled from the creep atthe surface. We conclude that models of the Quaternary tectonics of Central and Eastern Europeshould not neglect the long wavelength, nearly aseismic deformation affecting the upper crust in theRomanian and Bulgarian regions