HYDROGEN CONSIDERATIONS

To the Editor: I found the article on the “Hydrogen Horizon” in the May issue to be quite interesting and informative.

Like electricity, hydrogen is primarily a means of transmitting and utilizing energy. It is clear that neither the media nor our politicians understand that virtually all hydrogen is produced by converting another basic source of energy. I believe we do a disservice to society when we fail to convey that fact.

I heartily agree that we need to utilize all potential sources of energy and means of utilizing them, and that in time petroleum will be more valuable as a feedstock and lubricant than as a fuel. However, merely converting natural gas, which in the short term is the primary source, to hydrogen will only put further burdens on a source of energy that is also of limited long-term supply.

COLTON MEYER, P.E.
WALNUT CREEK, CALIF.

To the Editor: The article “Hydrogen Horizon” in the May edition left out “the rest of the story” (in the words of Paul Harvey). First of all, to achieve a “hydrogen economy” would require at least 11 major technical breakthroughs, four of which would be at the “miracle” level, and might require divine intervention.

Quoting The Economist, July 2008: “Hydrogen is just about the worst possible vehicle fuel.” Scientific American, May 2004, stated, “Fuel-cell cars, in contrast [to hybrids], are expected on about the same schedule as NASA’s planned trip to Mars and have about the same level of likelihood.”

As to sources of hydrogen, the article recommends natural gas, but the Department of Energy is currently reporting U.S. reserves sufficient only for 10 years at our current rate of consumption. Also, the price of natural gas has increased by a factor of 15 in the past 24 years, and there is no reason to believe that the price will decrease or stabilize.

To supply the hydrogen economy by electrolysis would require an exponential increase in generating capacity, which of course, would be mainly from nuclear and coal-fired power plants.

Although certain parts of the U.S. have substantial wind and insolation potential, they are also lightly populated. Biomass would barely make a dent in our demand for fuel.

It is my opinion that research funds would be better spent on technologies in support of pluggable hybrid vehicles.

ALAN B. CARSON, P.E.
AUSTIN, TEXAS

Editor’s note: The writer is the chair of the ASME Central Texas Section.

To the Editor: I read “Hydrogen Horizon” with a bit of concern that no one touting the “hydrogen economy” seems to have considered the safety implications of hydrogen fueling stations or vehicle onboard reformers. Hydrogen is very hard to contain due to the small size of the molecule—seeping through threaded connections, O-ring joints, packing, gaskets, and even into the grain structure of metals used to contain it.

It has a very wide flammability range, stretching from 4 percent to 74 percent concentration in air. It is colorless, odorless, and burns with a virtually invisible flame. I virtually shudder to think of the hazard to the public of “hydrogen filling stations” or of a vehicle accident that ruptures a hydrogen line from a pressurized tank.

The hydrogen will seep out into the atmosphere and, if trapped under a vehicle, with its wide explosive range will most assuredly form a very hazardous explosive mixture needing only a stray spark from the light switch on a car door or something similar.

I am not trying to be a nay-sayer, but someone needs to take a good look at protecting the users before rushing into this.

BYRON WOOLDRIDGE
KEMAH, TEXAS

GOOD WORK

To the Editor: I just finished reading the August issue of Mechanical Engineering. Your group is doing a superb job nowadays.

The magazine is interesting! You have article after article that even an ol’ retired duck like myself can find interesting. It made a great evening. Thanks.

H. S. EZZARD, P. E.
COLUMBUS, N.C.

WHERE ARE THE JOBS?

To the Editor: I have been a tenured associate engineering professor (aerospace and mechanics at the University of Alabama Tuscaloosa) and I am currently a practicing engineer at John Deere in the field of CAE.

You mentioned in your editorial (August) that there are now more than 131,000 engineers enrolled in grad school in the U.S. What I wonder about is how many grad-level engineers are really needed.

Of course as faculty members we often encouraged better students to go to grad school but—career-wise—was this good advice? Will there be appropriate jobs available for these students on graduation?

It would be nice if ASME would take the lead in trying to forecast the demand for new mechanical engineers at B.S., M.S., and Ph.D. levels. This would help students make career decisions.

I also think this information would be very useful to academic leaders in forecasting enrollments and to political leaders setting industrial policy.

A drop in projected demand for MEs could indicate economic problems ahead, for instance.

WILLIAM K. RULE
WATERLOO, IOWA

ANALYSIS AND SYNTHESIS

To the Editor: I read the letter “Math and Mechanics” in the April issue, which commented on the article “Sign of Future Engineers” of last December.

There are two general types of knowledge applied in making things (or devices): analysis and synthesis. Analysis is the study of the property and behavior of a device. This type of knowledge typically consists of laws of science and procedures to apply the laws, including mathematics.

Synthesis proposes devices that may possess a required property and behavior. However, a proposed device needs to be analyzed to evaluate whether it actually possesses the required property and behavior. In short, while making a device—an ultimate goal of engineering—engineers intertwine these two types of knowledge; neither of them can be omitted.

Learners who possess a background of math and physics will find it easier to learn the analysis type of knowledge, while learners who have experience of devices may find it easier to learn the synthesis type of knowledge.

Engineering programs worldwide put more weight on analysis than on synthesis. This is why students with a stronger math background are likely show a better performance than students with a weaker math background in their overall engineering study.

An important implication of the discussion is that the quality of students educated in the contemporary engineering program may be quite behind what our society and industry need. This implication is behind the call for reforming contemporary engineering programs by a recent movement in engineering education labeled the CDIO Initiative.

W.J. ZHANG, P.ENG.
SASKATOON, SASKATCHEWAN

Editor’s note: The April letter cited intuitive mechanical skills as a sign of potential engineers. The source quoted in the original article gave high priority to mathematical ability. Both are archived at www.memagazine.org. The CDIO Initiative, www.cdio.org, says it is an organization aimed at keeping engineering education focused on “real-world systems and products.”

CORRECTION

An image on page 35 of the October issue, illustrating the use of analysis software to study the loads on merchant vessels, showed the wrong type of ship. The correct image has been published with the online version of the article, “Finding Forces,” on Mechanical Engineering Magazine Online, at www.memagazine.org.