Abrasion of flat rotating shapes

We report on the erosion of flat linoleum "pebbles" under steady rotation in a slurry of abrasive grit. To quantify shape as a function of time, we develop a general method in which the pebble is photographed from multiple angles with respect to the grid of pixels in a digital camera. This reduces digitization noise, and allows the local curvature of the contour to be computed with a controllable degree of uncertainty. Several shape descriptors are then employed to follow the evolution of different initial shapes toward a circle, where abrasion halts. The results are in good quantitative agreement with a simple model, where we propose that points along the contour move radially inward in proportion to the product of the radius and the derivative of radius with respect to angle

Scattering from Solutions of Star Polymers

We calculate the scattering intensity of dilute and semi-dilute solutions of star polymers. The star conformation is described by a model introduced by Daoud and Cotton. In this model, a single star is regarded as a spherical region of a semi-dilute polymer solution with a local, position dependent screening length. For high enough concentrations, the outer sections of the arms overlap and build a semi-dilute solution (a sea of blobs) where the inner parts of the actual stars are embedded. The scattering function is evaluated following a method introduced by Auvray and de Gennes. In the dilute regime there are three regions in the scattering function: the Guinier region (low wave vectors, q R << 1) from where the radius of the star can be extracted; the intermediate region (1 << q R << f^(2/5)) that carries the signature of the form factor of a star with f arms: I(q) ~ q^(-10/3); and a high wavevector zone (q R >> f^(2/5)) where the local swollen structure of the polymers gives rise to the usual q^(-5/3) decay. In the semi-dilute regime the different stars interact strongly, and the scattered intensity acquires two new features: a liquid peak that develops at a reciprocal position corresponding to the star-star distances; and a new large wavevector contribution of the form q^(-5/3) originating from the sea of blobs.Comment: REVTeX, 12 pages, 4 eps figure

Neural Relax

We present an algorithm for data preprocessing of an associative memory inspired to an electrostatic problem that turns out to have intimate relations with information maximization

Airflow design in refrigerated retail display cabinets and its impact on food quality

© 2019 International Institute of Refrigeration. All rights reserved. This paper investigates how refrigerated display cabinet airflow design can enhance temperature distribution and potentially reduce food waste. Conventional refrigerated retail cabinets have a single column of cold air from the top to the bottom of the merchandising envelope. By contrast separating the retail space into individual cells, each with its own shorter air-curtain reduces infiltration and improves temperature control. The quality and safety of bagged salad over an extended display period was evaluated in a conventional and multiple short air-curtain cabinet. At the end of the test period there was a visible difference in cabinet temperature and relative humidity, which had a direct impact on the salad organoleptic quality and microbiological safety. The temperature band was 11.2ºC and 5.4ºC in the conventional and multiple air curtain cabinets respectively, resulting in a higher degree of salad wilting and shrivelling and an increase on total yeast counts on the conventional cabinet

Study of Xenopus orthologs of novel genes expressed in the mouse AVE

info:eu-repo/semantics/publishedVersio