Ice cream did much to popularize ice cream recipes and make its consumption into a fashionable middle-class pursuit. She wrote four books: "Ices Plain and Fancy: The Book of Ices" (1885), "Mrs. A.B. Marshall's Book of Cookery" (1888), "Mrs. A.B. Marshall's Larger Cookery Book of Extra Recipes" (1891) and "Fancy Ices" (1894) and gave public lectures on cooking. She even suggested using liquid nitrogen to make ice cream. Ice cream soda was invented in the 1870s, adding to ice cream's popularity. The invention of this cold treat is attributed to American Robert Green in 1874, although there is no conclusive evidence to
Gas–liquid contactor is higher for equipment with higher values of gas–liquid interface surface area, so gas–liquid contactors with high surface area (e.g. packed column, spray tower) are often preferred when it is important to lower the cost of the equipment. Liquid hold-up is also an important factor for the economy of the process, because for low values of liquid hold-up a bigger equipment is needed to have the same heat and mass transfer velocity. For this reason, gas–liquid contactors with low liquid-hold-up (e.g. falling-film column) in general are not used at industrial scale. Gas–liquid contactor A gas–liquid contactor is a particular chemical