Innovative metallic solutions for alpine ski bases

Ski manufacturers are interested in improving ski performance in terms of rapid sliding, excellent trajectory control, and reduced maintenance. A possible approach to achieve this goal is based on substitution of the base material, moving from the standard ultra-high-molecular-weight polyethylene to metallic solutions. Despite their elevated mechanical properties, however, metallic materials exhibit a poor sliding behavior, at least in their original manufacture condition. Although the interaction between the ski base and snow is still an open field, the authors investigated the relationship between ice friction and material hydrophobicity. The wettability behavior of surfaces can be managed by surface patterning techniques, among which laser surface texturing (LST) is a promising method, permitting surface feature modification from the micrometer- to millimeter-scale, and attractive for industrial applications. Herein, the tribological properties of two metallic materials are investigated and a process to reduce the sliding friction against snow is proposed. The LST is used to realize dimple patterning on the metallic surfaces, where the laser parameters are used to control the dimple geometry and surface wettability using untreated substrates as a reference condition. Finally, characterization using a prototype snow tribometer was performed to determine the friction coefficient and sliding performance of the laser-treated metallic surfaces

Disordered materials: an introduction

Springer Series: Advanced Texts in Physic

Disordered Materials: An Introduction

This self-contained text introduces the physics of structurally disordered condensed systems at the level of advanced undergraduate and graduate students. Among the topics are the geometry and symmetries of the structural units used as building blocks of extended structures, the various kinds of disorder, the phenomenology and the main theories of the glass transition, the structure of amorphous systems and the techniques to investigate it, the evolution of system's structure with its size (clusters) and the presence of orientational order in the absence of translational order (quasicrystals). In the second edition, the treatment of the mode coupling theory of the glass transition has been enlarged and connects now to a new section on collective excitations in disordered systems. Special attention has been devoted to nanometer-sized disordered systems, with emphasis on cluster-assembled materials. Questions of what governs the occurrence and stability of quasicrystals, the features of the amorphous to quasicrystal transformation and its reverse transition are discussed. The conditions leading to nano-quasicrystalline phases of technological interest are examined. Throughout the text relevant recent experimental and theoretical results are discussed so as to give readers insight into the currently most vibrant research topics. From the reviews of the first edition: "The text is clearly presented, amply illustrated and has approximately 45 references with an equivalent amount of further reading [...] it provides a fresh viewpoint which makes it well worth careful reading... [and] provides a stimulating and novel coverage of a difficult subject area." Glass Technolog

Laser-surface interactions for new materials production

This book provides an overview on nanosecond and ultra-short laser-induced phenomena and the related diagnostics

Fisica applicata allo sci alpino

Capitolo sulla interpretazione fisica della tecnica della scuola italiana di sci alpin

Sliding on snow of Aisi 301 stainless steel surfaces treated with ultra-short laser pulses

Surface irradiation of AISI 301 with ultra-short linearly polarized pulses between 247 fs and 7 ps resulted in laser induced periodic surface structures (LIPSS). Scanning electron microscope micrographs taken after the laser treatment show the formation of sub-micrometer sized arrays of nearly parallel ripples slightly differing from each other, depending on the specific treatment adopted. Static contact angle data indicate that LIPSS induce a marked hydrophobic behavior of the treated surfaces. The friction coefficient of laser treated and pristine AISI 301 surfaces gliding on compact snow was compared to that of ultra-high molecular weight polyethylene. The friction coefficients of the laser treated samples are intermediate between those of bare AISI 301 and of UHMWPE. The changes in contact angle and surface morphology of the samples after extensive tribometer tests were tested to investigate the durability of LIPSS