Sales of natural-gas powered big rigs could jump as much as fivefold this year as falling prices for both natural gas and the carbon fuel tanks required for such trucks come down, the Wall Street Journal says. Lowe's, Procter & Gamble, UPS and PepsiCo are among the major US companies that have gone on record saying they're expanding their fleet of trucks that can run on either compressed natural gas (CNG) or liquefied natural gas (LNG). For instance, UPS is buying 1,000 natural-gas trucks by year-end, and P&G, whose fleet is about seven percent natural gas, is looking to boost...