To the Editor: Thanks to Frederick Willis (Letters, October 2000) who set me, and no doubt others, straight on the NASA satellite observations of temperature variations in the lower atmosphere, which disagree with results from computational climate models. Those of a skeptical persuasion will feel this is sufficient reason to reject all conclusions of the models, while others will look to improve the science behind, and accuracy of, the computations. While we wait for a resolution, we need to acknowledge that uncertainty in models cuts both ways; their predictions may be excessively pessimistic or unreasonably reassuring.
While surface temperature measurements (see IPCC's Summary for Policymakers of its report, Climate Change 2001--the Scientific Basis, available at www.ipcc.ch) show a significant warming trend (corrected for the heat island effect of cities, contrary to some suggestions), the most persuasive evidence for temperature increase comes from phenomena such as the worldwide retreat of glaciers, bleaching of corals, borehole measurements, and movement of species northward and to higher altitudes.
All these are integrated measures, not spot values, and none are affected by heat from cities; any one of them could be "just one of those things," while, taken together, they suggest a substantial probability that temperatures are increasing.
Industry and society can adapt to slow, steady, predictable changes, so I believe it rational to create moderate, gently increasing incentives for greenhouse gas reduction. If climate change does start to affect us significantly, we will have made some progress at minimum costs--and if it all goes away, we will not have wasted significant resources.
Technology innovations are making significant reductions in greenhouse emissions possible, and many low-cost, or even profitable reduction opportunities are available.
The IPCC suggests that only 60 percent of the man-made effect is due to [CO.sub.2]--and one-quarter of that is caused by deforestation, leaving some 45 percent due to fossil fuels. Reducing emissions of the GHGs responsible for the other 40 percent, i.e. methane (20 percent), [N.sub.2]O (6 percent), and fluorinated gases (14 percent), may be better value than some cuts in [CO.sub.2].
SCORING A HIT
To the Editor: The article "How Well Can It Take a Hit?" (Mechancial Engineering Design, March), was interesting to me. However, the language was so esoteric that it reminded me of some of the articles in the Applied Mechanics Review of the 1950s.
I enjoyed the magazine, especially the article "Science, Experience, and Common Sense."
I have been retired for many years, since before PCs became common and when CAD was still new. We had to put our analysis on the big mainframe computers. We also had to write many of our own programs after solving the differential equations.
Robert J. Grave, P.E.
HUNTING FOR MORE
To the Editor: Paul Sharke's article "No Hunting" in the May issue provides some nice insight into the "truck hunting" phenomena.
One item that may have been overlooked is the fact that a three-piece truck fitted with new wheels can increase the hunting threshold of a truck 5 to 10 mph more than the threshold indicated on the graph included with the article. This 5 to 10 mph increase of the hunting threshold is substantial when considering the speed at which most freight trains travel.
The article also does not indicate a few important parameters to support the graph (all of which can affect test results): car type tested, wheel profile (new or worn), and side bearing type (constant contact, roller, or block). Of course, there are other factors that come into play (coefficient of friction of the rail, suspension, etc.), but those parameters mentioned should have been included in the article to provide some insight.
I have no doubt that the "swing motion" dampens out lateral inputs, but please provide the pertinent detail when relaying the information. How can a person compare apples and oranges?
PROSPERITY IN NUMBERS
To the Editor: Lester Su brings up some interesting points in his May commentary ("Washington Window"). The issues of engineering graduation rates and H-1B Visas are not only vital to engineers and our various societies like ASME, but are of the utmost importance to every American.
I urge every engineer to download the National Bureau of Economic Research's Working Paper 7723, "Should Government Subsidize Supply or Demand in the Market for Scientists and Engineers?" by economist Paul M. Romer (wwwnber.org/papers/w7723). Romer reports on the link between the number of engineers and the economic growth rate. He has some interesting ideas about how to increase the economic growth rate by tweaking the output of engineers from universities.
For instance, how many prospective engineering students have salary information on graduates of the schools they're applying to? If engineering schools made that kind of information available, perhaps engineering as a profession would be more attractive.
Many engineers believe that having fewer engineering graduates helps them personally achieve a higher salary, following the law of supply and demand. However, it is also true that higher rates of economic growth fuel most of the industries by which engineers are employed. So, to some extent, more engineering graduates can lead to higher engineering salaries.
All the engineering societies and professional organizations must get together and speak with one voice. Not only do all engineers benefit when our country produces more engineers, but society itself benefits through increased economic growth and better living conditions.
Eric P. Krieg, P.E.
Des Plaines, Ill.
RINGS AROUND THE SUN--OR NOT
To the Editor: I noticed the interesting illustration by Philippe Lechien for the cover of the June ME Power magazine, and thought I would write. The illustration is a somewhat distorted armillary sphere, showing various power generation components, viewed by two scientists or engineers looking for "More Power" to run various appliances and vehicles in our world.
The "world" you show includes the sun, and certainly conveys an idea of the large scope of the power problem today. The armillary sphere is an ancient astronomical device used to illustrate the old geocentric universe (the "world" in the parlance of the day), and is a most fascinating device, both in its historical roots and mechanically.
The term "armillary sphere" would literally denote a sphere made of rings (armillaries), but its usage has been to refer to the astronomical device, so I stick with that when I use the term. Some armillary spheres were quite fancy (and expensive), depending on the amount of detail incorporated in the model.
My own armillary sphere is a lot simpler, but was still quite a project to make. It is a wonderful teaching tool to convey understanding of the geocentric model of things. I got interested in armillary spheres because of my avocational work on the geocentric/heliocentric controversy.
I offered a $1,000 reward to solicit proof that Copernicus was right about the physical arrangement and operation of the universe, as of course all of us "know" from our education, and it has been an eye-opening experience for me to find out what the situation actually is in the realm of world views. Downright shocking to an engineer!
That has led to an off-and-on windmill tilting with the Establishment over this matter, which of course has profound philosophical and religious implications. Some of my Catholic pen pals are fascinated to learn that the old Catholic Church had it right concerning Galileo, too.
Editor's note: The author in 1980 issued a four-page challenge on behalf of the Pittsburgh Creation Society for unambiguous proof that the Earth rotates and travels in an annual orbit around the sun.
THE MIND GAME
To the Editor: As a graduate mechanical engineer, business owner, and participant in business support of vocational education, I am attracted by published discussions relating to pragmatic uses of education.
From my perspective as an employer, one phase of education is preparation for entering the workplace with the requisite skills to perform general and specific tasks in a culturally (read "socially") acceptable manner.
Harry T. Roman ("Professionally Speaking," February) described a conference that spoke to the desirability of school/business partnerships and to an educational paradigm to meet the "new" needs of business.
I suggest that training relevant to the workplace has been implicit in the design of our system of public education from the beginning, but has not been the case experientially. Like most human endeavors, the issue is complex, with participants (government, community, education, and business) unwilling to accept their share of fault.
Gerson S. Ecker
To the Editor: In reply or rebuttal to Bill Weitze (Letters, May) of San Jose, Calif., concerning my letter to the editor about railroad gauge, I do not think he realizes the extent that I believe the railways of the future should increase the rail gauge.
I am thinking of a railway gauge where the rails are wide enough to take a semi tractor and trailer crosswise between them. I believe such a width would allow a substantial increase in speed without having to go to maglev or other high-tech solutions.
Widening the gauge would allow for ease of loading and unloading of automobiles and semi trailers at auto train stations. Widening the gauge would allow for the larger loads that are now carried by trucks to be taken by rail.
A fuel crisis is looming on the horizon of this country as well as the world. There are more efficient transportation systems than a 150-horsepower power plant in a vehicle that moves three or four people. The railroad is one.
Payload tons per mile per gallon are the key to fuel, natural resource, and environmental conservation. Two of the reasons we are not using the railway system to the extent that this country needs to are speed and cross-sectional area of the loads carried. Superwide gauge systems could give us that speed increase and allow super loads to be moved.
Editor's note: The writer's original letter proposing superwide gauge railroads was published in December 2000.
To the Editor: In the article "Speaking Different Languages" (February), it's a good thing that software developers realized that users were having problems with exchanging designs between different CAD programs.
The attempt to use STEP as the universal file format is a good one, but that means each program needs a translator to convert the file from the program's format to STEP.
The solution that I believe would partially solve this problem, and at the same time protect the software developers' secrets, is to approach the subroutines as a blackbox. If each subroutine has exactly the same inputs, whatever happens in the subroutine would differ from one software vendor to another, but protect the developer's secret algorithm.
Consider this example: If we say the command used to draw a line is LINE, the standard input should always be the start point and the end point of the line. So the log file should include the statement: LINE [(x1, y1, z1), (x2, y2, z2)]. If we say the command used to draw a fillet is FILLET, the standard input should always be the start point, end point, center point, radius, and the direction of the fillet. So the log file should include the statement: FILLET [(x1, y1, z1), (x2, y2, z2]), (xc,yc,zc), (r), (+/-)].
If this method is used universally, it would hopefully make the process of exchanging designs easier, without the need to use translators since a simple log file will be used.
Sherif Samy Shenouda
ACCOLADES FROM AFRICA
To the Editor: I joined ASME about two years ago, and it has been rewarding. Thank you for all that you do at ASME, for its members in particular and our profession in general. ASME is not just for its members alone, but for all mechanical engineers. It's a pity I didn't join ASME in my student days.
Your magazine, Mechanical Engineering, is one of a kind. It is informative and educational in addition to being a good reference source.
I look forward to the day when I will be able to connect to the Internet with ease. Then I will be able to participate more in the society's activities and be updated daily by Mechanical Engineering's Web site.
I am a 28-year-old mechanical engineer, an associate member of ASME in Nigeria.
Once again, thank you and more grease to your elbows.
Rivers State, Nigeria