Johnson, Paul B.

Liepmann, Hans W.

Name not available

Letters 
Barren Desert? 
Los Angeles 
EDITOR: 
The articles on energy in the March- 
April Engineering and Science are most 
interesting. Congratulations. However, 
it is not clear what you mean by "low 
quality land" or "barren desert land" on 
page 7. The casual reader might get the 
idea you referred to some of the glorious 
land which gives meaning to "wide 
western skies" and where live a profusion 
of exotic plants, such as cactus, so hard 
to grow anywhere else. 
Some of the world's most skilled 
inhabitants live there, too-who manage 
such spectacular feats as never taking a 
drink, soaring for hours, and so on. 
Every passenger on an airplane who 
looks out the window as well as pinches 
the stewardesses knows you mean the 
cities by such phrases as "barren." One 
glance shows miles and miles of regions 
such as roofs, exterior walls, pavements, 
etc.-all as barren as God and man can 
make them, and hence about as low 
quality as is possible to imagine. Putting 
solar collectors there affects no life style 
at all. If made strong enough to walk on, 
they will be an interesting design feature. 
Thank you for your congratulations, 
and we join you in your admiration for 
the natural desert. The barren desert 
land we refer to is that which has been 
made barren by man-excluding cities. 
As we also said on page 7,  the federal 
government owns about 100,000 square 
miles in the Southwest, a significant 
portion o f  which has been used for such 
purposes as gunnery ranges and the 
testing of nuclear weapons. By contrast, 
using some o f  that land for producing 
solar energy might be almost idyllic. 
A Dissenter Dissents 
Pasadena 
EDITOR : 
As one of the two dissenters in the 
faculty meeting of February 21,I take a 
special interest in the article on graduate 
degrees in social sciences in the last issue. 
I would strongly suggest that a new course 
on the evaluation of polls be included in 
the curriculum to avoid conclusions 
drawn from biased samples-like the 
faculty meeting of the 21 st in which most 
of the supporters appeared and most of 
the dissenters remained absent. In any 
case, a more representative sample, I am 
sure, would eliminate my feeling of lone- 
liness. If I had realized my picture would 
be next to the article, I would have 
changed my facial expression. 
H. W. LIEPMANN 
Professor of Aeronautics 
Research 
o~~ortunities in 
The Asphalt Institute 
suggests projects in five vital areas 
Phenomenal advances in roadbuilding techniques dur- 
ing the past decade have made it clear that continued 
highway research is essential. 
Here are five important areas of highway design 
and construction that America's roadbuilders need to 
know more about : 
1. Rational pavement thickness design and materials 
evaluation. Research is needed in areas of Asphalt 
rheology, behavior mechanisms of individual and com- 
bined layers of pavement structure, stage construc- 
tion and pavement strengthening by Asphalt overlays. 
Traffic evaluation, essential for thickness design, 
requires improved procedures for predicting future 
amounts and loads. 
Evaluation of climatic effects on the performance 
of the pavement structure also is an important area 
for research. 
The Asphalt Institute' @ 
32 College Park, Maryland 20740 \ A,& 
2. Materials specifications and construction quality- 
control. Needed are more scientific methods of writing 
specifications, particularly acceptance and rejection 
criteria. Additionally, faster methods for quality-con- 
trol tests a t  construction sites are needed. 
3. Drainage of pavement structures. More should be 
known about the need for sub-surface drainage of 
Asphalt pavement structures. Limited information 
indicates that untreated granular bases often accumu- 
late moisture rather than facilitate drainage. Also, in- 
dications are that Full-Depth Asphalt bases resting 
directly on impermeable subgrades may not require 
sub-surface drainage. 
4. Compaction and thickness measurements of pave- 
ments. The recent use of much thicker lifts in Asphalt 
pavement construction suggests the need for new 
studies to develop and refine rapid techniques for 
measuring compaction and layer thickness. 
5. Conservation and beneficiation of aggregates. More 
study is needed on beneficiation of lower-quality base- 
course aggregates by mixing them with Asphalt. 
For background information on Asphalt construc- 
tion and technology, send in the coupon. 
r------------------------- 1 1 OFFER OPEN TO CIVIL ENGINEERING 1 
I STUDENTS AND PROFESSORS 
I THE ASPHALT INSTITUTE I 
I College Park, Maryland 20740 I I 
1 Gentlemen: Please send me your free library on I 
1 Asphalt Construction and Technology. I I 
Name Class or rank i 
School ! 
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