When it comes to the UAV, or unpiloted aerial vehicle, technology keeps emphasizing the "U" all the time. It is a long-range goal of NASA and other aviation research groups to develop autonomous aircraft to the point where they can safely share airspace with conventional commercial planes.

The art hasn't reached that state yet, but it has perhaps come a step closer. The Defense Advanced Research Projects Agency and NASA teamed up to demonstrate that an autonomous UAV can exercise enough control to be refueled in flight.

The demonstration used an F/A-18 jet modified to operate on its own, without the intervention of pilots. A tanker trailed a line with a 32-inch basket that connected with the refueling probe of the jet twice in six tries.

Connecting on its own: NASA pilot Dick Ewers and flight test engineer Marty Trout fly hands-off over California during an autonomous air refueling demonstration.

According to DARPA, the exercise, called the Autonomous Airborne Refueling Demonstration, used GPS guidance and an optical tracker. There were pilots aboard the autonomous plane as a safety precaution, and to set up test conditions and help in data collection. They had relinquished control of the jet during the demonstration.

The tanker was on auto pilot during the connection. No fuel was transferred during the exercise.

According to the NASA test pilot, Dick Ewers, when the system missed, the jet backed up smoothly to a restarting point. He said the computer-guided system had "none of the last-second, high-gain stabs at the basket that we often see with human pilots."

We reached Lt. Col. Jim McCormick, the DARPA program manager, by e-mail. "The challenge was twofold: The autonomous aircraft had to be able to fly accurately, but it also needed to know accurately where it needed to fly," he wrote."The main challenge was to integrate GPS, inertial, and optical sensors to determine precisely where to fly (the second part) and to configure the flight control system to actually fly there within the allowable error budget."

McCormick told us, "We are not aware of any instance where a single autonomous aircraft has connected to another aircraft in flight. It might be more accurate to say that this was the first time an autonomous aircraft made a probe-to-drogue connection."

According to McCormick, "We chose to demonstrate the probe-and-drogue refueling method because it is the most challenging for autonomous systems. The precise station-keeping capability we've dem- onstrated applies equally to the boom-and-receptacle method used by most Air Force aircraft."

DARPA said that autonomous in-flight refueling will enable "affordable, persistent unmanned strike systems." The demonstration flight, over Edwards Air Force Base in California, was the seventh in a proof-of-concept program for UAV airborne refueling.

DARPA reported that the two planes were "operating in benign flight conditions."

According to McCormick, "DARPA has extended the demonstration for a total of eight more flights. These flights are intended to explore the robustness of autonomous refueling in more challenging operating conditions. We intend to look at turbulence, plugging in turns, joining from further out, and handling greater variation in drogue positions."

A vapor-compression cooling system is currently under development for future lunar lander and lunar outpost applications.

The developer is Mainstream Engineering Corp., a Rockledge, Fla., company that specializes in advanced thermal control and energy conversion. It was awarded a half-million dollar contract by NASA Johnson Space Center for the design, fabrication, testing, and flight readiness assessment of a gravity-insensitive heat pump.

The research involved in this program builds on two of Mainstream's successful projects: oil-less compressors that are now onboard the International Space Station, and solar-powered refrigerated containers currently under development for the Army.

The NASA contract, with options running through 2009, was placed against General Services Administration Schedule 871 for Professional Engineering Services. GSA schedules establish long-term, government-wide contracts with pre-approved commercial firms, such as Mainstream, at pre-approved rates. Thus, contracts are awarded more rapidly.
Mainstream's GSA schedule includes mechanical, chemical, and electrical engineering disciplines.

Sulfur has been a dangerous nuisance of our age, and much has been done to curb the release of sulfur into the atmosphere. It is even being stripped out of diesel fuel.

Coal-fired power plants have been cited as major contributors of sulfur- and nitrogen-bearing compounds that have clouded the atmosphere and upset the chemical balance of lakes and streams. And, as they usually do, engineers have developed solutions. Scrubbers at power plants clean flue gases of sulfur dioxide, and selective catalytic reduction curbs the release of nitrogen oxides.

Sulfur sorbent: A naturally occurring mineral that can be a food additive is removing SO3 from the exhaust at American Electric Power's coal-fired Gavin power plant in Cheshire, Ohio.

One of the country's leading suppliers of electricity, American Electric Power, observes, however, that there is still more to do. Maybe it's one of the ironies of life, but AEP has found that coal-fired plants equipped with scrubbers and SCR systems certainly emit less SO₂ and NO_x, but they actually release more sulfur trioxide.

AEP, based in Columbus, Ohio, has developed technology specifically for use by coal plants equipped with scrubbers and SCR to capture the SO₃ that would otherwise come out of the smokestack. According to AEP, the system uses a naturally occurring mineral, sodium sesquicarbonate. It contains sodium carbonate, or soda ash, and sodium bicarbonate. It is a food additive, which can serve variously as an acidity regulator, anticaking agent, gelling agent, or raising agent in products ranging from cream to processed fruit.

The mineral is injected into the flue gas stream as a sorbent to draw SO₃. According to AEP, there is a visible reduction in the blue plume associated with sodium trioxide emissions.

According to a spokeswoman at AEP, the company is using the system so far at one plant, two units of the Gavin plant in Cheshire, Ohio. She was unable to quote numbers, but said there had been a reduction in SO₃ emissions after the system was installed.

AEP has granted a non-exclusive license of the technology to Babcock & Wilcox Co., the energy services company based in Barberton, Ohio.

When the Timken Co. tells us that proper lubrication is critical to machine performance and component longevity, it probably comes as no surprise. According to Timken, which is one of the leading names in the bearing business, it has seen research indicating that more than 50 percent of all bearing damage is related to inadequate or improper lubrication. Now that's specific.

In an effort to keep things covered, as it were, the Canton, Ohio, manufacturer has added a multipoint lubricator that it calls C-Power to its line of lubricant-delivery devices.

According to the company, the centralized lubricator can dispense grease to machinery as far away as 100 feet through six lubrication points, making it useful for bearings, chains, guideways, and other industrial equipment components. Capable of operating in temperatures ranging from -4°F to 140°F (-20°C to 60°C), Timken C-Power can preset lubrication intervals between one day and 24 months.

In addition to the C-Power centralized multipoint lubricator, Timken also offers G-Power (gas-powered) and M-Power (motorized) single-point lubricators.

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