The reputation and history of Damascus steel has given rise to many legends, such as the ability to cut through a rifle barrel or to cut a hair falling across the blade. A research team in Germany published a report in 2006 revealing nanowires and carbon nanotubes in a blade forged from Damascus steel. Although many types of modern steel outperform ancient Damascus alloys, chemical reactions in the production process made the blades extraordinary for their time, as Damascus steel was superplastic and very hard at the same time. During the smelting process to obtain Wootz steel ingots, woody biomass and leaves are known to have been used as carburizing additives along with certain specific types of iron rich in microalloying elements. These ingots would then be further forged and worked into Damascus steel blades. Research now shows that carbon nanotubes can be derived from plant fibers, suggesting how the nanotubes were formed in the steel. Some experts expect to discover such nanotubes in more relics as they are analyzed more closely.
The double-ring ceremony describes the exchange of wedding rings by and for both spouses. In several European nations such as the Nordic countries, it is common to exchange plain engagement rings of the same form for both sexes, and typically, an additional, more precious, and bejeweled wedding ring is given to the bride. In the nuptials, the groom’s ring becomes a wedding ring also, and can be bestowed anew by the bride as a part of the wedding ceremony. The engagement is commonly a matter of agreement between the two, and the wedding rings are chosen together. Both engagement and wedding rings are worn on the left hand, the bride having both rings together. Occasionally, the groom receives a separate wedding ring. In Germany and Austria, both parties use engagement rings worn on the left hand. At the nuptials, a wedding ring is placed on the right hand, as in several east European nations, including Bulgaria, Poland, and Russia. This can be a new ring for the bride or both, or reusing the engagement rings. Any engagement rings can then remain on the left hand or be transferred to the right hand. In Germany, it has been customary for both the bride and the groom to wear a wedding ring since at least the 1870s and mentions of couples exchanging rings during the wedding ceremony in the Netherlands can be found at least as far back as 1815. In Brazil, Mexico and Spain both sexes also wear engagement rings, and the groom’s ring often becomes a wedding ring in the nuptial exchange ceremony. In The Netherlands plain bands can be worn on either hand, left for Catholics and right for Protestants. When engaged, both bride and groom wear what will be the wedding band on the opposite hand and switch hands after the wedding.