Search

In 1890, former students of Arnold Guyot at the University of Neuchatel dedicated a 'large glacial boulder from Neuchatel' to his memory, now in front of Guyot Hall at Princeton University. We established that this block originated with all certainty from Upper Carboniferous conglomerates of the Salvan-Dorenaz Basin, the relics of which crop out in the Alps of western Switzerland and eastern France. During the Last Glacial Maximum, the boulder travelled from the lower Rhone Valley on the back of the Pleistocene Rhone Glacier to Neuchatel from where, later, it crossed the Atlantic and was transported to Princeton. Guyot's name is familiar to geologists because of the term 'guyot', introduced 1946 by Harry Hess for 'curious flat-topped peaks scattered over millions of square miles in the Pacific basin', many of which are now known to represent drowned carbonate platforms., International Journal of Earth Sciences, 110, ISSN:1437-3254, ISSN:1437-3262

Friction and wear minimizing coatings are crucial for applications in combustion engines and medical implants. Their performance is typically limited by mechanical failure especially due to local overload. In this work, the contact damage creation, evolution, and final morphology of hydrogenated diamond-like carbon (DLC)-coated titanium (Ti) substrates are investigated. The influence of the DLC film thickness and the elastic–plastic deformation of the Ti on the contact damage are studied by microindentation and static finite-element analysis. Film thickness, indenter radius, and applied load as well as the elastic–plastic deformation of the Ti are shown to significantly affect contact damage. A failure plot is presented with the location of first failure in the DLC and compared to the experimental observation. In addition, a case study with variable fracture toughness of the DLC and its influence on the failure plot is shown. The stress distribution in the DLC follows a transition from a membrane-like to a plate-like deformation behavior upon increasing the DLC film thickness. Thin DLC films reveal increased cracking in the inner zone of the indent, while thicker DLC films reveal pronounced edge cracking. These edge cracks were correlated to pop-ins in force–displacement curves upon microindentation. Finally, a film thickness optimization process is presented for hard and brittle films on soft and ductile metallic substrates., Journal of Materials Science, 50 (7), ISSN:0022-2461, ISSN:1573-4803

Come noto nella teoria delle decisioni il valore atteso di una particolare scelta non può essere sempre preso come criterio per determinare la decisione ottimale dal punto di vista razionale. Daniel Bernoulli in una fortunata memoria scritta nel 1731 e contenuta nel volume dei Commentarii Academiae Scientiarum Imperialis Petropolitanae pubblicato nel 1738, per primo suggerì di utilizzare in luogo del valore atteso un valore morale o utilità attesa che una persona è disposta a spendere e che dipende dal patrimonio che possiede. La proposta di Bernoulli ha avuto grandi influenza ed eco, fino ai nostri giorni, in davvero molte discipline e diversi settori di ricerca. In particolare la prospettiva aperta dal saggio è alla base del cosiddetto approccio utilitarista, sia in filosofia che in politica ed economia, per il quale ogni decisione individuale dovrebbe essere ispirata dalla necessità di massimizzare la propria utilità attesa e l’insieme delle decisioni individuali dovrebbe andare nella direzione della massimizzazione del benessere collettivo. Senza inoltrarci qui in una discussione di questi od altri importanti aspetti, riassumiamo prima brevemente l’idea di Bernoulli ed il contesto in cui fu concepita e presentiamo poi la traduzione integrale del suo articolo dall’originale latino.