Researchers in North Dakota say they have been working for four years on a process that converts soybean or canola oil into aviation turbine fuel. The biofuel, which is now almost ready for an Air Force test, runs colder and cheaper than conventional jet fuel and is more environmentally friendly, the Grand Forks Herald reported on Friday. The researchers said they have found a way to solve a problem with the fuel's tendency to "gel" at low temperatures, and that it is now working at temperatures of 75 below zero (Fahrenheit). Air Force scientists have tested earlier versions of the fuel, and found it performed as well as regular JP-8 jet fuel. The biofuel is being studied by a new sustainable-energy initiative between the University of North Dakota and North Dakota State University in Fargo. Wayne Seames, a UND chemical engineering professor, and Ted Aulich, a senior researcher at the Energy and Environmental Research Center, have been working together on the project. "There's still a lot of work to do," Seames told the Herald.