Response of copper to Equal Channel Angular Pressing with different processing temperature

AbstractStructural property relationship indicates the significance of Ultra Fine Grain (UFG) for attainment of enhanced strength without any chemistry alteration. Ultra fine grain structure can be produced by Equal Channel Angular Pressing (ECAP) by proper selection of die geometry, route (method specimen rotation for each number passes) and processing temperature. The present study illustrates the significance of processing temperature on attainment of higher strength with ductility. Compared to room temperature, processing with 2000C, results in significant contribution of ECAP by way of structural-strengthening. However, both the processing indicates a critical value of 3, passes, for attaining the desired results

Kinetic oscillations in the NO + CO reaction on Pt(100): Experiments and mathematical modeling

The reaction of NO and CO on Pt(100) exhibits two branches of steady state production of N2 and CO2 and the occurrence of kinetic oscillations. This system was studied under steady flow conditions in the 10−6mbar total pressure range using low‐energy electron diffraction‐(LEED), work function measurement, and mass spectrometry for determination of the reaction rate. These studies revealed that kinetic oscillations can only be initiated from one of the two stable reaction branches. Two separate existence regions were detected in which the oscillations are always damped. Oscillations can be very reproducibly excited by slight decreases in temperature. The 1×1 hex phase transition of the surface structure was observed to take place only in one of the two regions of reaction rate oscillations. Its influence seems to be of minor relevance to the mechanism of oscillations as oscillations in one region occur on the surface that maintains a 1×1 structure. The experiments were modeled by a set of coupled differential equations based on knowledge about the elementary reaction steps. The model calculations reproduced the steady states of the reaction as well as the occurrence of kinetic oscillations in different ranges in excellent agreement with experimental observation. In the model, the phase transition also has no relevance for the oscillation mechanism. The occurrence of oscillations can be rationalized in terms of a periodic sequence of autocatalytic ‘‘surface explosions’’ and the restoration of an adsorbate‐covered surface. The damping, experimentally observed, is attributed to insufficient spatial coupling between different regions of the surface

A national clinician–educator program: a model of an effective community of practice

Background: The increasing complexity of medical training often requires faculty members with educational expertise to address issues of curriculum design, instructional methods, assessment, program evaluation, faculty development, and educational scholarship, among others. Discussion: In 2007, The Royal College of Physicians & Surgeons of Canada responded to this need by establishing the first national clinician–educator program. We define a clinician–educator and describe the development of the program. Adopting a construct from the business community, we use a community of practice framework to describe the benefits (with examples) of this program and challenges in developing it. The benefits of the clinician–educator program include: improved educational problem solving, recognition of educational needs and development of new projects, enhanced personal educational expertise, maintenance of professional satisfaction and retention of group members, a positive influence within the Royal College, and a positive influence within other Canadian academic institutions. Summary: Our described experience of a social reorganization – a community of practice – suggests that the organizational and educational benefits of a national clinician–educator program are not theoretical, but real

Comparative anatomical dimensions of the complete human and porcine spine

New spinal implants and surgical procedures are often tested pre-clinically on human cadaver spines. However, the availability of fresh frozen human cadaver material is very limited and alternative animal spines are more easily available in all desired age groups, and have more uniform geometrical and biomechanical properties. The porcine spine is said to be the most representative model for the human spine but a complete anatomical comparison is lacking. The goal of this descriptive study was to compare the anatomical dimensions of the cervical, thoracic, and lumbar vertebrae of the human and porcine spine in order to determine whether the porcine spine can be a representative model for the human spine. CT scans were made of 6 human and 6 porcine spines, and 16 anatomical dimensions were measured per individual vertebrae. Comparisons were made for the absolute values of the dimensions, for the patterns of the dimensions within four spinal regions, and normalised values of the dimensions within each individual vertebra. Similarities were found in vertebral body height, shape of the end-plates, shape of the spinal canal, and pedicle size. Furthermore, regional trends were comparable for all dimensions, except for spinal canal depth and spinous processus angle. The size of the end-plates increased more caudally in the human spine. Relating the dimensions to the size of the vertebral body, similarities were found in the size of the spinal canal, the transverse processus length, and size of the pedicles. Taking scaling differences into account, it is believed that the porcine spine can be a representative anatomical model for the human spine in specific research questions

Systems and technologies for objective evaluation of technical skills in laparoscopic surgery

Minimally invasive surgery is a highly demanding surgical approach regarding technical requirements for the surgeon, who must be trained in order to perform a safe surgical intervention. Traditional surgical education in minimally invasive surgery is commonly based on subjective criteria to quantify and evaluate surgical abilities, which could be potentially unsafe for the patient. Authors, surgeons and associations are increasingly demanding the development of more objective assessment tools that can accredit surgeons as technically competent. This paper describes the state of the art in objective assessment methods of surgical skills. It gives an overview on assessment systems based on structured checklists and rating scales, surgical simulators, and instrument motion analysis. As a future work, an objective and automatic assessment method of surgical skills should be standardized as a means towards proficiency-based curricula for training in laparoscopic surgery and its certification

Untangling approaches to management and leadership across systems of medical education

Aims: How future doctors might be educated and trained in order to meet the population and system needs of countries is currently being debated. Incorporation of a broad range of capabilities, encompassed within categories of management and, increasingly, leadership, form part of this discussion. The purpose of this paper is to outline a framework by which countries’ progress in this area might be assessed and compared. Methods: Key databases and journals related to this area were reviewed. From relevant articles potential factors impacting on the incorporation of aspects of management and leadership within medical education and training were identified. These factors were tested via an online survey during 2013 with six members of a European Association of doctors who promote medical involvement in hospital management, including members from countries less represented in the health management literature. Results: A framework for analysing how management and leadership education is being approached within different systems of healthcare is developed and presented. Conclusions: More systematic work across a wider range of countries is needed if we are to have a better understanding of how countries within and beyond Europe are approaching and progressing the education of doctors in management and leadership. Keywords: Medical education, Management, Leadership, Competency framework

The mechanism of kinetic oscillations in the NO + CO reaction on Pt(100)

Under constant flow conditions the reaction of NO and CO to the products N2 and CO2 on a Pt(100) surface exhibits multiple steady states and kinetic oscillations. Using Video LEED, measurement of the work function change and of the reaction rate the kinetic oscillations were investigateed in the 10−7 mbar range. Kinetic oscillations were found to occur in two separate temperature regions around 400 K. In the upper temperature range, the oscillations are coupled to the 1 × 1 ⇌ hex phase transition, while those in the lower temperature range proceed entirely on a 1 × 1 surface. Based on a mathematical model consisting of three coupled differential equations it could be shown that the 1 × 1 ⇌ hex phase transition is not essential for the oscillating mechanism. The main role in the mechanism can instead be ascribed to the autocatalytic behavior of the surface reaction between COad and NOad