Influence of manufacturing technology on selected Al alloy

Diplomová práce se zabývá plátovanými plechy hliníkové slitiny EN AW-2024 v závislosti na různých dobách výdrže při vysokých teplotách během tepelného zpracování a jejími vlivy na materiálové vlastnosti. V první části diplomové práce v literární rešerši je zpracována teoretická část zabývající se jak čistým hliníkem, tak jeho slitinami a tepelným zpracováním vybraných slitin. Řešení experimentů bylo prováděné na normalizovaných zkušebních plochých tyčích po statické zkoušce v tahu, z kterých byly zpracované materiálové vlastnosti, studium lomových ploch a zhodnocení chemického složení v jednotlivých lokalitách slitiny, vzhledem na výskyt intermediárních fází.This thesis deals with clad sheets of aluminum alloy EN-AW 2024 in relation with different endurance times during heat treatment and its effects on material properties. In the introduction there is a literature review dealing with pure aluminum, its alloys and heat treatment of selected alloys. The experiments were carried out on standard flat test bars for static tensile test, from which were processed material properties. Also studies of fractured surfaces and evaluation of the chemical composition of alloys in different specific locations due to the occurrence of intermediate phases

A scuticociliate causes mass mortality of Diadema antillarum in the Caribbean Sea

Echinoderm mass mortality events shape marine ecosystems by altering the dynamics among major benthic groups. The sea urchin Diadema antillarum, virtually extirpated in the Caribbean in the early 1980s by an unknown cause, recently experienced another mass mortality beginning in January 2022. We investigated the cause of this mass mortality event through combined molecular biological and veterinary pathologic approaches comparing grossly normal and abnormal animals collected from 23 sites, representing locations that were either affected or unaffected at the time of sampling. Here, we report that a scuticociliate most similar to Philaster apodigitiformis was consistently associated with abnormal urchins at affected sites but was absent from unaffected sites. Experimentally challenging naïve urchins with a Philaster culture isolated from an abnormal, field-collected specimen resulted in gross signs consistent with those of the mortality event. The same ciliate was recovered from treated specimens postmortem, thus fulfilling Koch's postulates for this microorganism. We term this condition D. antillarum scuticociliatosis