Review of top of rail friction modifier tribology

© 2016 Informa UK Limited, trading as Taylor & Francis Group.The aim of this paper was to review the current state of research for top of rail friction modifiers (TORFM). In the railway industry, friction modifiers is a catch all term for a wide range of products applied for different purposes which has led to confusion. It is hoped that recently published definitions will aid industry to a better understanding of the different products and how they function. The benefits of friction modifiers are well understood with a large body of research supporting the benefits. Comparatively, there is a lot less knowledge of the optimum amount of product to achieve the benefits or how far down the track from an application site the benefit will be seen. Modelling of the products is another area where there is little research, with most of the modelling papers found focussing on dry wheel–rail contact due to the complexity of introducing a third-body layer to a friction force model. Furthermore, only one paper was found which relates how friction modifiers are affected by contaminants or other applied products such as lubricants. With many different products applied to wheels and rail for different purposes, understanding their interaction is key. At the time of this review, there are currently no standards that prescribe how TORFM should behave although the European Committee for Standardisation is currently developing them at the moment. This review has also attempted to appraise the research against a set of criteria. Depending on how many of the criteria the piece of research filled, it was categorised as A, B or C. It was found that most of the research was of category, this was mainly due to only one test method being used or the scale presented. Category A research incorporated modelling or multiple test-scales to support the results presented

Cytogenetic studies of early myeloid progenitor compartments in Ph<SUP>1</SUP>- positive chronic myeloid leukemia. II. Long-term culture reveals the persistence of Ph<SUP>1</SUP>-negative progenitors in treated as well as newly diagnosed patients

We recently showed that long-term marrow cultures can be used to demonstrate the presence of Philadelphia (Ph1) negative progenitors in patients with newly diagnosed Ph1-positive chronic myeloid leukemia (CML). We now report results for 6 chronic phase patients studied 5-83 mo postdiagnosis and an additional 3 newly diagnosed patients. Marrow metaphases were exclusively Ph1-positive. Clonogenic assays revealed a minor population of Ph1-negative progenitors in 3 cases (1 treated, 2 untreated). Long-term marrow culture adherent layers contained Ph1- negative progenitors in 6 cases (3 treated, 3 untreated). Whenever this occurred, the Ph1-negative population had become the only one detectable within 3-4 wk, and this was always associated with a rapid decline of the Ph1-positive population. For 2 of the 3 cases where Ph1- negative progenitors were not detected, there was a similar rapid decline in the Ph1-positive population in culture. In the other case, Ph1-positive progenitors were maintained at levels typically seen in normal long-term marrow cultures. These results suggest that chromosomally normal stem cells may persist for a considerable period in the marrow of some, but perhaps not all, patients with CML, even in the face of maintenance chemotherapy. In addition, they provide new evidence of heterogeneity in this disease, as shown by the variable ability of Ph1-positive progenitor populations to be maintained in vitro

Towards a Standard Approach for Wear Testing of Wheel and Rail Materials

Examination of the literature for wear testing methodologies for wheel and rail material reveals that while only a few different techniques have been used there is a wide variety in exactly how the tests have been conducted and the resulting data reported. This makes comparison of the data very difficult. This work, carried out as part of the International Collaborative Research Initiative (ICRI) which is aiming to bring together wheel/rail interface researchers from across the world to collate data and knowledge to try to solve some of the common problems that are faced, has examined the different approaches used and attempted to pull together all the good practice used into a test specification for future twin disc testing for wheel and rail materials. Adoption of the method will allow data to be compared reliably and eventually enable data to be compiled into wear maps to use as input, for example, to multi-body dynamics simulation wear prediction tools

Strigolactones inhibit auxin feedback on PIN-dependent auxin transport canalization

Directional transport of the phytohormone auxin is a versatile, plant-specific mechanism regulating many aspects of plant development. The recently identified plant hormones, strigolactones (SLs), are implicated in many plant traits; among others, they modify the phenotypic output of PIN-FORMED (PIN) auxin transporters for fine-tuning of growth and developmental responses. Here, we show in pea and Arabidopsis that SLs target processes dependent on the canalization of auxin flow, which involves auxin feedback on PIN subcellular distribution. D14 receptor- and MAX2 F-box-mediated SL signaling inhibits the formation of auxin-conducting channels after wounding or from artificial auxin sources, during vasculature de novo formation and regeneration. At the cellular level, SLs interfere with auxin effects on PIN polar targeting, constitutive PIN trafficking as well as clathrin-mediated endocytosis. Our results identify a non-transcriptional mechanism of SL action, uncoupling auxin feedback on PIN polarity and trafficking, thereby regulating vascular tissue formation and regeneration

Accelerating the Laser Induced Phase Transition in Nanostructured FeRh via Plasmonic Absorption

By ultrafast x ray diffraction UXRD , it is shown that the laser induced magnetostructural phase transition in FeRh nanoislands proceeds faster and more complete than in continuous films. An intrinsic 8 amp; 8201;ps timescale is observed for the nucleation of ferromagnetic FM domains in the optically excited fraction of both types of samples. For the continuous film, the substrate near regions are not directly exposed to light and are only slowly transformed to the FM state after heating above the transition temperature via near equilibrium heat transport. Numerical modeling of the absorption in the investigated nanoislands reveals a strong plasmonic contribution near the FeRh MgO interface. The larger absorption and the optical excitation of the electrons in nearly the entire volume of the nanoislands enables a rapid phase transition throughout the entire volume at the intrinsic nucleation timescal