Some remarks on particle size effects on the abrasion of a range of Fe based alloys

The low-stress three body abrasion behaviour of a range of steels was investigated. The tests were carried out in a rubber wheel tester (according to ASTM G65-94, reapproved in 2000) at room temperature. The abrasive particles used were angular alumina particles of four different sizes. The results showed that, in general, the smaller particles (50 8m and 125 8m average size) caused more damage. With these particles, observations of surface morphology indicarted a more intense cutting and ploughing action, leading to more damage, whereas bigger particles i.e. larger 250 8m and 560 8m particles produced less damage, and their action involved more plastic deformation type wear. The 304 SS had a lower abrasion resistance than the 310 SS. For the austentic and ferritic steels the subsurface deformation was larger for impact with the coarser particles. Variations in substrate hardness had no effect on the abrasive behaviour observed. On the whole, the hardest steel (mild steel in martensitic condition) showed the higher extent of damage, irrespective of particle size

Will the reddit rebellion take you to the moon? Evidence from WallStreetBets

In early 2021, several stocks receiving attention from retail traders known as “meme stocks” soared in value. A primary source of information regarding these stocks is from the social media platform Reddit, specifically from a subreddit known as WallStreetBets (WSB).This paper investigates whether a simple and easily implementable trading strategy following the WallStreetBets (WSB) subreddit can produce alpha. We document no evidence this is the case. Though we do observe a positive relation between WSB submissions and abnormal trading volume, we find that a portfolio that goes long buy recommendations and short sell recommendations each day is not profitable on a risk-adjusted basis. Holding periods from one day to one year fail to produce alpha. These findings are robust to a variety of different portfolio formation strategies. Our results provide an early look at the data following the explosion of interest in social media inspired retail investing. © 2022, The Author(s) under exclusive licence to Swiss Society for Financial Market Research. The available download on this page is the author manuscript accepted for publication. This version has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process

Uniaxial pressure dependence of magnetic order in MnSi

We report comprehensive small angle neutron scattering (SANS) measurements complemented by ac susceptibility data of the helical order, conical phase and skyrmion lattice phase (SLP) in MnSi under uniaxial pressures. For all crystallographic orientations uniaxial pressure favours the phase for which a spatial modulation of the magnetization is closest to the pressure axis. Uniaxial pressures as low as 1kbar applied perpendicular to the magnetic field axis enhance the skyrmion lattice phase substantially, whereas the skyrmion lattice phase is suppressed for pressure parallel to the field. Taken together we present quantitative microscopic information how strain couples to magnetic order in the chiral magnet MnSi.Comment: 23 pages, includes supplemen

Versatile module for experiments with focussing neutron guides

We report the development of a versatile module that permits fast and reliable use of focussing neutron guides under varying scattering angles. A simple procedure for setting up the module and neutron guides is illustrated by typical intensity patterns to highlight operational aspects as well as typical parasitic artefacts. Combining a high-precision alignment table with separate housings for the neutron guides on kinematic mounts, the change-over between neutron guides with different focussing characteristics requires no readjustments of the experimental set-up. Exploiting substantial gain factors, we demonstrate the performance of this versatile neutron scattering module in a study of the effects of uniaxial stress on the domain populations in the transverse spin density wave phase of single crystal Cr