Marrowfat peas "medullare"). The word was coined around 1730 from "marrow" and "fat". Another source says the peas were named because people wanted plump ("fat") peas of the "Maro" variety, a Japanese variety introduced to England 100 years ago. Marrowfat peas Marrowfat peas are green mature peas that have been allowed to dry out naturally in the field, rather than be harvested whilst still young like the normal garden pea. They are used to make mushy peas, and also the snack food wasabi peas. Marrowfat peas with a good green color are exported from England to the Middle East and Japan for
Ground freezing the Big Dig used ground freezing during some of its tunneling, to allow its wide tunnels to be built under or through soil that supported existing infrastructure that would have been difficult or expensive to support using more traditional excavation methods. Some ground freezing projects use common salt brine as the refrigerant, but other projects benefit from using more exotic refrigerants, like liquid nitrogen. In Northern Canada and Arctic Alaska, passive pipe systems are used that do not require any external power to keep the ground frozen. These systems use in-ground evaporators and above-ground radiators filled with liquid refrigerant. When