OBJECTIONS ON CLIMATE 

To the Editor: Your editorial in the November 2007 issue regarding concerns about climate change is not supported by the knowledgeable scientific community.

Please refer to the article entitled "Environmental Effects of Increased Atmospheric Carbon Dioxide" by Arthur B. Robinson, et al., of the Oregon Institute of Science and Medicine (oism.org). The authors show historical data that the Earth's temperature correlates with the sun, not hydrocarbon use. The paper cites 136 references that support the conclusions.

The United States is close to adopting an international agreement that would ration the use of energy. The treaty is based on flawed ideas, according to Frederick Seitz, past president of the National Academy of Sciences.

Life has been changing on Earth for centuries, beginning long before the introduction of modern energy conversion machines. Please reconsider. You may want to enlighten the confused public, among and currently supported of global warming.

Michael A. Chaszeyka
Western Springs, Ill.

IS FUSION A FACTOR?

To the Editor: I have noticed that few if any articles regarding our future energy needs, especially regarding carbon loading, have addressed the possible role that nuclear fusion power plants may play. For example, is fusion energy expected to have any significant impact by 2054, the end date of Jeffrey Winters's interesting article, "Wedge Factor" (October 2007)?

Is it likely that fusion plants will be scalable? What technical obstacles have been overcome and what remains? Are there competing designs? Is there any concept of what a final overall plant design might entail?

There must be a dozen more questions that would interest today's mechanical engineers, whether or not fusion power plants are on or still over the horizon. Any new major source of energy could slow down and spread out the use of fossil fuels over a considerably longer time period, perhaps within the capabilities of the Earth to handle the reduced carbon load.

Albert Winroth
Saratoga Springs, N.Y.

POLITICS OF CARBON 

To the Editor: This letter is written in response to the October article "Wedge Factor."

I have worked in the electric power industry for over 40 years. The whole issue of carbon release is not a technical problem. It is, however, a social, financial, and political problem.

Our own Congress, for all of its arm waving and pontificating about what the current administration (or any past one, for that matter) has or has not done to address the climate change and greenhouse gases issues, has already decided we can wait to do something until after the next election, where one party believes it will get a veto-proof majority in both bodies and be able to dictate policy.

We abandoned central cities in droves all over the world quite some time ago for many reasons. Good luck getting substantial numbers of folks to go back. Or do you plan to devalue their real estate investments to the point that they are bankrupt? Most baby boomers are looking for their new homes away from the city.

What happens to major industries, especially travel and tourism? If you are really going to curb carbon emissions, airplanes, trains, buses, ships, taxis, and cars cannot be used for all of these current "frivolous trips." Are you going to tell the retiring baby boomers all over the planet that the many vacations they saved for they can no longer have? Are you going to tell the poor folks in many places that tourists now frequent that they are out of a job?

If you try to do anything that will radically change the public's established way of life, you are likely to fail.

Allen Kasper, P.E.
Oak Harbor, Wash.

EXTRA CREDITS

To the Editor: I enjoyed reading Frank Wicks's article, "50 Years of Nuclear Power," in the November 2007 Mechanical Engineering. While there is no doubt that Sam Untermyer and Walter Zinn were responsible for the invention of the boiling water reactor, the article does not do justice to the hundreds of world scientists, engineers, and operating personnel who evolved the 5 MWe natural circulation at Vallecitos into 1,400 MWe advanced boiling water reactors.

That evolution required solutions to challenging technical, licensing, management, and materials problems, which are covered in my recently published book 50 Years in Nuclear Power: A Retrospective, published by the American Nuclear Society. I hope Frank Wicks has read the book in order to grasp the contributions made by those who assured that BWRs currently are operating safely, reliably, and economically.

Salomon Levy
San Jose, Calif.

STORAGE ISSUES

To the Editor: Nice to know that the licensing process for nuclear power plants is being streamlined ("Licensing Renewed," October 2007).

The big question about nuclear power is still unanswered: What do you do with the waste? You only have to store it for 50,000 years.

Dave Erskine
Mountainview, Calif.

ADVANCES IN PROSTHESIS

To the Editor: I give heartfelt thanks for the vast amount of progress during the past 40 years in the body control of mechanisms for the disabled. I am greatly impressed by the degree of control given to the disabled in many, many ways to improve quality of life as described in your article "Machines for Life" in the December 2007 issue.

I became involved in the 1960s in research studies directed toward improving the control of prosthetic arms. In this time of need for all the war casualties, development of these means of control is indeed a blessing.

Thank you for publishing "Machines for Life."

Roy Wirta
La Mesa, Calif.

STEAMBOAT CORROSION

To the Editor: For some time, I have been intrigued by the stories of boiler explosions in steamboats and other plants in the 19th century. In the U.K. alone, more than 600 lives were lost in boiler explosions between 1860 and 1900. In the October 2007 issue, my attention was drawn to similar catastrophes that have afflicted the U.S.A., too.

I have just read Frank Wicks's article, "Pressure's On," in which he writes about the explosion on the Pennsylvania in 1858 that killed Mark Twain's brother. My curiosity then led me to the disaster of the steamboat Sultana, in which over 1,700 people were killed in 1865.

I should say at this point that I am a British corrosion specialist and that I have been interested in stress-corrosion cracking for around 30 years. Stress-corrosion cracking (SCC) is a particular form of corrosion that was unknown until the 20th century.

From the early days of the construction of steam plants using simple ferrous materials, rusting was obviously a problem. It was known that the addition of caustic potash (potassium hydroxide) to boiler feedwater would reduce the corrosion to a minimum when the pH (a measure of the acidity of the water) was increased from 7 (neutral) to 10 (alkaline). However, it was not known that this introduced all the necessary factors for stress-corrosion cracking, i.e., the combined action of specific material (mild steel), specific environment (hydroxide ions), and stress.

Clearly, in many instances of fatal explosions, the operational stress of the boiler could well have been within safe limits, but the residual stress in the steel around the rivet holes or other highly cold-worked areas would have been more than enough to initiate cracks through the thickness of the plates. Even a short crack, invisible in the conditions, would be enough to cause catastrophic failure under pressure.

It is very likely that many engineers have been blamed for these catastrophes in which they themselves lost their lives. Sometimes they lived to protest their innocence, in vain.

The scapegoat for the disaster on the Sultana seems to be an engineer in the repair yard who had fitted a new plate only days before the accident. We will never know how many of these terrible incidents were actually the fault of poor operation and maintenance, and how many were caused by the (then) unknown form of corrosion called SCC.

Ken Trethewey
Nuclear Department
Defence College of Management and Technology
Gosport, U.K.