Notre Dame Cathedral ‘not saved yet’ and still at risk of collapse | World news

The French general appointed to oversee the reconstruction of Notre Dame Cathedral has said the iconic building is still at risk of collapse more than six months into the efforts to restore it. Gen Jean-Louis Georgelin said the cathedral is “not saved yet” and has to undergo a delicate operation to remove fused scaffolding around the spire, destroyed by a devastating fire last April. “The cathedral is still in a state of peril,” Georgelin told the French broadcaster CNews. “There is an extremely important step ahead, which is to remove the scaffolding,” he said. Georgelin, who has described the conservation and restoration of the cathedral as “an immense challenge”, added that the condition of the ceiling vaults was not fully known and he could not guarantee they “won’t fall apart”. However, he said initial observations on the current state of the 12th-century edifice were “reassuring”, adding: “We feel quite confident.” The cathedral’s rector, Monseigneur Patrick Chauvet, said a fortnight ago the cathedral was so fragile there was a “50% chance” the structure may not be saved if the scaffolding fell on stone vaults weakened by the inferno. “Today we can say there is maybe a 50%...

HYDROGEN is gathering support as a potential replacement for fossil-based fuels such as coal, oil, and

HYDROGEN is gathering support as a potential replacement for fossil-based fuels such as coal, oil, and natural gas. In theory, and for most applications, this is an attractive option: a relatively plenteous material whose use causes only a small environmental disturbance compared to, for instance, airborne emissions of carbon dioxide or particulate materials (PM2.5 and PM10). Unlike fossil-based fuels, hydrogen needs to be processed out of something else and delivered to the point of use. This article describes some of the delivery options, the factors that can influence the choice, and some of the associated challenges. Transporting almost any fluid requires for a number of questions to be asked, perhaps the most relevant of which are: How much? How pure? What pressure? Clearly the answers to these will depend on the end use. For most applications, hydrogen will be used as a gas, but that does not mean that it is always transported as a gas. The majority of the hydrogen moved around has been in steel cylinders or in specially-designed and refrigerated tube trailers. Single cylinders typically contain typically 5-8 Nm3 of hydrogen at pressures ranging between 150–300 bar. BOC ha...