Assessment of laser cladding as an option for repairing/enhancing rails

This paper presents results of testing carried out to assess the wear and RCF performance of laser clad rail. Stronger and harder materials can be laser clad on top of the working surfaces of standard (e.g. 260 grade) rail in order to improve wear and RCF life. A twin-disc method has been used to assess the suitability of various candidate cladding materials. The materials were clad on top of 260 grade rail discs and were tested against a disc of standard wheel material. Wear was measured by weighing the discs before and after each test. An Ellotest B1 differential eddy current crack detector was used to detect RCF cracks in the rail disc. Four clad materials were used namely, Hadfield, Stellite 6, Maraging and 316 Stainless Steels. In the tests carried out, wear was not always reduced with the cladding. It is assumed that these tests were not long enough for some of the materials to fully work harden and therefore wear rates would improve with a greater number of test cycles. However, all but the Stainless Steel showed that they did not deform under the cyclic loading applied and would offer a greatly enhanced RCF life

Non-AIDS defining cancers in the D:A:D Study-time trends and predictors of survival : a cohort study

BACKGROUND:Non-AIDS defining cancers (NADC) are an important cause of morbidity and mortality in HIV-positive individuals. Using data from a large international cohort of HIV-positive individuals, we described the incidence of NADC from 2004-2010, and described subsequent mortality and predictors of these.METHODS:Individuals were followed from 1st January 2004/enrolment in study, until the earliest of a new NADC, 1st February 2010, death or six months after the patient's last visit. Incidence rates were estimated for each year of follow-up, overall and stratified by gender, age and mode of HIV acquisition. Cumulative risk of mortality following NADC diagnosis was summarised using Kaplan-Meier methods, with follow-up for these analyses from the date of NADC diagnosis until the patient's death, 1st February 2010 or 6 months after the patient's last visit. Factors associated with mortality following NADC diagnosis were identified using multivariable Cox proportional hazards regression.RESULTS:Over 176,775 person-years (PY), 880 (2.1%) patients developed a new NADC (incidence: 4.98/1000PY [95% confidence interval 4.65, 5.31]). Over a third of these patients (327, 37.2%) had died by 1st February 2010. Time trends for lung cancer, anal cancer and Hodgkin's lymphoma were broadly consistent. Kaplan-Meier cumulative mortality estimates at 1, 3 and 5 years after NADC diagnosis were 28.2% [95% CI 25.1-31.2], 42.0% [38.2-45.8] and 47.3% [42.4-52.2], respectively. Significant predictors of poorer survival after diagnosis of NADC were lung cancer (compared to other cancer types), male gender, non-white ethnicity, and smoking status. Later year of diagnosis and higher CD4 count at NADC diagnosis were associated with improved survival. The incidence of NADC remained stable over the period 2004-2010 in this large observational cohort.CONCLUSIONS:The prognosis after diagnosis of NADC, in particular lung cancer and disseminated cancer, is poor but has improved somewhat over time. Modifiable risk factors, such as smoking and low CD4 counts, were associated with mortality following a diagnosis of NADC

CHARACTERIZATION OF ORIENTATION OF ONE-WAY AND 2-WAY DRAWN ISOTACTIC POLYPROPYLENE FILMS

X-ray diffraction, Fourier Transform infra-red (FTi.r.) spectroscopic and refractive index measurements have been utilized to characterize the state of molecular orientation in one-way and two-way (biaxially) drawn isotactic polypropylene (iPP) films. It is shown that the use of all three techniques leads to much greater confidence in the orientation averages deduced than can be obtained by using any two of the techniques. Orientation parameters in terms of values in machine, transverse and normal directions have been evaluated and compared quantitatively for the different techniques. The results indicate that with one-way drawing the chain axes of both crystalline and amorphous regions orient towards the direction of drawing. The crystalline chains are more highly oriented than the amorphous chains and tend to orient towards the plane of the film, whereas the amorphous chains tend to be more uniaxially oriented towards the draw direction. In balanced, simultaneously two-way drawn films the crystalline chains are more highly oriented towards the plane of the film than the non-crystalline chains. For a sequentially, equibiaxially drawn iPP film, the orientations of the chain axes of both the crystalline and amorphous regions were found to be higher in the second draw (i.e. transverse) direction than in the first draw direction. The orientation of the crystalline chains was very close to the plane of the film, whereas the amorphous chains were almost uniaxially oriented with respect to the second draw direction. In all the films there is a strong tendency for the b-axes of the crystallites to align normal to the plane of the film

Diagnostic criteria for pronival ramparts: site, morphological and sedimentological characteristics

Pronival ramparts are discrete debris accumulations found below steep rock faces at the foot of snowbeds or firn fields but they are often confused with moraines, protalus rock glaciers or rock-slope failure debris accumulations. This can be attributed to a poor understanding of the modes of rampart genesis, failure to recognise the significance of topography in their development and the use of inappropriate diagnostic criteria. Various characteristics have been suggested for identification of pronival ramparts but these are derived largely from relict features. Research on actively accumulating ramparts has shown that some of the suggested criteria are no longer useful. This paper reviews existing criteria and shows that, for diagnostic purposes, more emphasis should be placed on the attributes of actively accumulating features. A more robust set of criteria, derived from common characteristics of actively accumulating ramparts, are proposed that assists in discriminating relict and active pronival ramparts from other discrete bedrock cliff-foot debris accumulations.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1468-0459hb201