Subject: Re: Idle query: how good are math and science teaching outside the U.S.?
From: m94jbr@sabik.tdb.uu.se (Johan Braennlund)
Date: 11 Jan 1997 17:22:16 GMT
Michael Weiss (columbus@pleides.osf.org) wrote:
: Anyway, whatever the truth about the U.S., I'd be interested in
: hearing impressions from other countries. If you, kind reader, were
: educated outside the U.S. and still reside there, what is your feeling
: about the average level of math and science instruction in your
: country? Has it declined over the years? How would you assess it
: today?
I live in Sweden, and here the level has certainly declined over the
last few decades. When my father was in high school, they were doing
things like introductory fourier analysis and calculus of several
variables, and you won't see anything like that now. Things were
probably more elitist back then - you had a few people who excelled
and many who understood little - but that's a problem of dividing
the students into appropriate groups, not of the level of education
itself.
For some reason (probably ideological, since most of
the governments we've had here since WW II have been socialist)
students are not put in groups corresponding to their interests
and/or abilities until 7th grade, and then only in math and English.
This reminds me of the old joke of the guy who put one foot in iced
water and the other in scorching hot water and said he has comfortable
on the average. I think the approach of keeping everyone in the same
group has a lot of disadvantages - you either cater to the lowest
common denominator and hamper the faster students or speed things up
and leave the slower ones behind.
When I started high school, seven years ago, you got to choose
your program of study according to what you were most interested in:
science/engineering, social sciences, languages, or more vocational
things such as carpentry or hairdressing and you followed a pre-
designed program, so you didn't get to choose the classes yourself.
The math and science education I got in high school was pretty good -
nothing like the one people got twenty years ago, but still okay. On
the math side, the things we studied are similar to what is studied in
the US, but I think there is a little more emphasis on understanding,
doing simple proofs and things like that, instead of the more mechanical
plug-in-the-numbers approach that seems to be prevalent in the US.
A few years ago, high school here was revamped into a system
very similar to the American one, where you got to choose all the
classes yourself, as long as you meet the requirements for graduation.
One of the consequences of this is that the introductory math classes
contain both carpentry students and those who are going to study
math and science. There's been a lot of complaints about this
system already, but the politicians are probably too pigheaded to
change it, so I fear things will go the same way here as they have
done in the US, unless something is done.
On the university side, things aren't looking very good either.
The funding for basic research has been cut dramatically, so much
that it was even critized by this year's Nobel prize winners, and
they aren't exactly known for making political comments. Also,
"political correctness" seems to be the catchphrase of the day at
the Department of Education - there's been a number of science
professorships that by the government's decision *only women may
apply for*. According to the diehard feminist who was hired by
the DoE to investigate gender inequality among university faculty,
this is a good way to bring more women into the sciences.
Well, I'd better quit... this is getting too long, and now that I'm
worked up about this I might say something I'll regret; the NNTP
servers have ears :-) .
Subject: IS THERE A CASE FOR THE ELECTRIC CAR?
From: ako@crl.com (Vlado Bevc)
Date: 11 Jan 1997 14:26:12 -0800
COMMENT ON DAN SPERLING'S ARTICLE PROMOTING ELECTRIC CARS IN
SCIENTIFIC AMERICAN, NOVEMBER 1996, P.54:
IS THERE A CASE FOR ELECTRIC VEHICLES?
Vlado Bevc Synergy Research Institute P.O. Box 561, San Ramon, CA
94583
In trying to make a case for electric vehicles it would be
desirable to clearly state the objectives of what impact is ex-
pected on the present environment. There are 194 million motor
vehicles in the United States 146 million of which are automo-
biles. These motor vehicles travel a total of 2,300 billion
miles per year consuming 137 billion gallons.[1] About 6 million
internal combustion engine powered vehicles are registered in the
Los Angeles county [2] and probably as many in New York. World-
wide 36 million automobiles are produced annually.[3]
The objective of the zero emission program could be replace-
ment of all internal combustion engine driven vehicles by zero
emission vehicles, or replacement of internal combustion vehicles
only in those urban areas where they are highly concentrated, or
perhaps the objective could only be compliance with the mandates
handed down by the air resources boards in the various states in
the hope that mandatory sales of electric vehicles may somehow
bring forth new technological developments. If we are talking
about no more than 5,000 electric cars, as the author seems to
indicate, their effect on the environment and the electric power
generation system would be minimal but if we are considering re-
placement on a scale that would approach the present number of
conventional cars we have to consider the effect on the air qual-
ity, discharges of lead and other heavy metals and the demand of
the electric power generating systems.
While the conversion of energy from storage cells in an
electric automobile may be more efficient than conversion of
gasoline to mechanical work the energy stored in the batteries
comes from the electric generating systems the efficiency of
which is only a few percent higher than that of the individual
internal combustion engine. For the electric car the conversion
of energy from the fuel to the "drive" simply starts at the elec-
tric power plant rather than in the engine. The implication that
the electric car has a 90 percent energy conversion efficiency is
therefore misleading. The question is not how efficient is the
motor but rather how efficient is the entire process from the
electric power generation plant to the propulsion mechanism.
Sperling allows that the overall advantage over the internal
combustion engine driven vehicle amounts to a mere 5 percent.
This advantage may well be offset by other disadvantages such as
transmission and charging losses for which we do not have a good
accounting. In estimates of this kind 5 percent figure implies a
marginal advantage which could be readily offset by aging of the
storage battery, line and charging losses. From Southern Califor-
nia Edison Company's promotional literature, for instance, it ap-
pears that 18 percent of energy used in charging up General Mo-
tors' EV1 vehicle is lost in the charging process.[4]
It is incorrect to say that battery powered vehicles would
eliminate emissions of carbon dioxide and volatile organic com-
pounds, the emissions are simply shifted from the tailpipe to the
electric power generating plants. Substitution of electric cars
would indeed move the emissions from areas where they would form
ozone but the coal-burning or other type of power generating
plants would still be producing carbon dioxide and contribute to
global warming. The Environmental Protection Agency [5] and oth-
ers [6] have conducted studies which show that the reduction of
global emissions attributed to the substitution of electric cars
for internal combustion vehicles are marginal at best and depend
very much on the fuel mix of the electric power plants in the
area and that in some cases pollution associated with the elec-
tric cars was even higher than that of internal combustion engine
driven vehicles. Considerable criticism was directed at EPA when
this report was circulated on grounds that assumptions of dif-
ferent fuel mixes for power generation would result in an outcome
appearing more favorable for the electric cars and its report
never was published in a final form.
Moreover, California will not be much longer one of those states
where electric power is generated by "tightly controlled" natural
gas plants. When the electric power utilities are deregulated in
California consumers will be able to buy power from the cheapest
suppliers and these may be the high polluting coal or oil fired
power plants in other states. Emissions from those plans when
attributed to the electric cars using their energy may well show
that the electric cars are as polluting as the internal combus-
tion vehicles.
Sperling notes that even if all (6 million) internal combus-
tion engine vehicles disappeared from the streets of Los Angeles
the air quality would still not meet the air quality standards.
A quantitative study by a Carnegie-Mellon University group
showed that replacement of 500,000 conventional cars by electric
vehicles would result by a reduction of ozone by less than 1 per-
cent or about one part per billion in either Los Angeles or New
York City.[7]
Pollution associated with the modern manufacture of bat-
teries would introduce about as much lead into the environment as
did the internal combustion engine driven vehicles using gasoline
containing tetraethyl lead. Lead is a highly toxic metal and use
of lead-acid battery powered cars on a scale that would notice-
ably affect local air quality would have a seriously damaging ef-
fect on humans. For example, 6 million electric cars with lead
acid batteries of capacity 16.2 kWh like the above mentioned EV1
would require 1.9 millon metric tons of lead for their batteries.
For comparison we note that in 1991 the total world production of
lead was 3.1 million metric tons.
In addition to New York State and Massachusetts nine other
states [8] have followed California's impetuous lead in imposing
mandatory zero emission vehicle sales quotas. If these mandates
are to be fulfilled some 900,000 electric vehicles will be in
operation by the year 2003. If all these vehicles were like Gen-
eral Motors' EV1 which has a battery capacity of 16.3 kWh at
specific energy of 50 watthour per kilogram of lead, they would
require 293,000 metric tons of lead or 63 percent of the total
current annual production of lead in the United States. If all 6
million cars in the Los Angeles basin were replaced with EV1s 1.9
millon metric tons of lead would be required for their batteries.
For comparison we note that in 1991 the total world production of
lead was 3.1 million metric tons.
The Carnegie Mellon University research team found that pro-
duction and manufacturing of lead required for batteries would
introduce as much or more lead into the environment as leaded
gasoline used to before it was eliminated.[9] The paper caused
considerable criticism from the proponents of electric cars but
its findings could not be substantially refuted.[10] The health
and environmental hazards associated with handling such quanti-
ties of this highly toxic metal would more than offset all the
effort in eliminating it from gasoline.
There is a theoretical limit of how much energy can be
stored in an electrochemical storage battery per weight of the
reacting material which is determined by the electronic confi-
guration of the elements and which cannot be exceeded. Therefore
all the efforts directed at "improving" the storage battery capa-
city can result in only a few percent increase in specific energy
per weight which will not change the situation. For lead this
limit is 175 Wh.
Application of higher specific energy lithium-ion batteries
for electric cars proposed by Nissan Motor Company appears to be
limited by the availability of lithium.[4] Based on current
world production of lithium of 10 million kilograms, a maximum of
2.9 million electric vehicles could be produced annually if all
of the production were applied to lithium batteries.[3] In 1995
the world production of cars was 36 million.
The prospect of cheap off-peak electric rates, often quoted
as an argument for the electric cars, also is misleading. Six
million cars charging at 6.6 Kw at night would place a demand of
39,600 megawatts on the electric utility system. The highest peak
demand in the Southern California Edison's system which occurs at
daytime in summer is about 17,000 megawatts. Although the situa-
tion could be mitigated by spreading or staggering the three hour
charging time over nine hours, thus reducing the additional
demand to 13,200 megawatts, there would no longer be an off peak
situation and, consequently, no off peak rate at night. At
today's prices the electric energy costs 14 cents per kWh in Cal-
ifornia and does not appear to be competitive with gasoline
prices.
Electric car promoters are apparently aware that lead-acid
batteries are a dead end, the efforts of the Advanced Battery
Consortium with an annual budget of $200 million plus notwith-
standing. For lead-acid batteries the ABC has set a modest goal
of a storage capacity of 50 to 80 Wh/kilogram which is a far cry
from the 13 kWh/kilogram that is stored in gasoline.[11] Even if
only 25% of the energy in gasoline can be converted into energy
for propulsion, gasoline still stores 65 times more useful energy
than is the expectation for the lead-acid batteries. At present
all the electric car models produced by the three big American
manufacturers use lead-acid batteries.
The figure of 2,100 kilojoules quoted as energy content of a
10 gallon tank of gasoline appears to be in error. Ten gallons of
gasoline contain 354 kWh or 1,274 megajoules, about 600 times
more.
The average power required for highway driving given as 10
kilowatts is also understated, it definitely does not represent
the power requirement for moving an average passenger car which
is 25 kW [12]. General Motors' Electric car EV1, advertised as
an advanced study in aerodynamics, which weighs just under 3,000
lb, requires 20 kW for cruising at 60 mph, according to published
specifications.[13]
If hydrogen is to be used for powering cars the required
quantity would have to be equivalent to that presently used by
internal combustion engine powered cars, viz., the available en-
ergy content of 250 billion gallons of gasoline [14]. The energy
stored in 250 billion gallons of gasoline is 9 trillion kWh; as-
suming that only 30 percent of it can be converted into traction
energy and that fuel cells are 50 percent efficient, an amount of
hydrogen packing 5.4 trillion kWh per year is required. At least
an equal amount of energy is needed to produce such an amount of
hydrogen by electrolysis, that is electric power generation
plants with clock capacity of 1,230,000 megawatt, if photovoltaic
power is contemplated, which is equivalent to the 123 power gen-
erating systems such as are needed to meet the average demand of
a utility like the Southern California Edison Company. It is
questionable if our society is prepared to build solar power gen-
erating plants of such capacity and the attendant hydrogen pipe-
lines and infrastructure can be built. The largest photovoltaic
power plant in California has a capacity of 5 megawatt.
The amount of hydrogen required would be 57.5 trillion cubic
feet, wt is 20,000 times that of the current United States annual
production which is 3 billion cubic feet at present.
There is no indication that ultracapacitors will power cars
for a long time to come.
Flywheel powered buses have been around since at least the
end of World War II but they never gained wide acceptance.
Fuel cells are not a suitable technology for electric cars
and will not be for a long time. When a number of 200 kW phos-
phoric acid natural gas burning fuel cells were first offered by
the Southern California Gas company, questions were raised wheth-
er their cost-effectiveness would support the approval of their
use.
Reason seems to have overruled the California Air Resources
Board which had to back down and modify its mandate so as to re-
quire that the manufacturers need only have the facilities for
production of electric cars available should there be a demand
for them [14]. The plan now appears to be requiring local
governments such as cities, counties, public service districts
and utilities to acquire electric cars for their fleets with the
taxpayers "painlessly" paying for the exorbitant costs of this
unappealing technology.[15]
REFERENCES
[1] Statistical Abstracts of the United States, 1995, U.S.
Department of Commerce, Washington DC, 1966.]
[2] State of California Department of Motor Vehicles, Estimated
Fee-paid Registration by County: 1992 Annual Report, Department
of Motor Vehicles, Sacramento, California, 1993.
[3] F.G. Will, Impact of Lithium Abundance and Cost on Electric
Vehicle Applications, Electric Power Research Institute, TR-
106556 8601, Palo Alto, 1996, p.2-3.
[4] Current, Electric Transportation News From Southern Califor-
nia Edison, 1, 1, Southern California Edison Company, Walnut
Grove, California, 1996.
[5] Preliminary Electric Vehicle Emissions Assessment, United
States Environmental Protection Agency, Regulation Development
and Support Division, National Vehicle and Fuels Emissions La-
boratory, Ann Arbor, 1993.
[6] H. Dowlatabadi, a.J. Krupnick, and A. Russell, Electric Vehi-
cle and the Environment: Consequences for Emissions and Air Qual-
ity in Los Angeles and U.S. Regions, Resources for the Future,
Washington, D.C., 1990.
[7] L.B. Leave, A.G.Russell, C.T. Henderson and F.C. McMichael,
Battery Powered Vehicles: Ozone Reduction versus Lead Discharges,
Environmental Science and Technology, 30, September 1996, p. 402
A.
[8] Delaware, Distric of Columbia, Maine, Maryland, New
Hampshire, New Jersey, Pennsylvania, Rhode Island, and Vermont.
[9] L.B. Leave, C.T. Hendrickson and F.C. McMichael, Environmen-
tal Implications of Electric Cars, Science, 268, March 19, 1995,
pp 993--995.
[10] D. Allen, Science 269, 1955, p. 741; R.C. Stempel, S.R.
Ovshinsky, Science 1955, 269, pp. 741-742; C.W. Gellings,
S.C.Peck, Science 1955, 269, p. 742; L.Gaines, M.Wang, Science
269, 1955, p., 742; R.J.Hwang, Science 269, 1955, p. 744; D.
Sperling, Science 1955, 269, p. 744.
[11] L.S. Marx, Standard Handbook for Mechanical Engineers, 7th
Edition, McGraw-Hill, New York, 1967, p. 11-4.
[12] L.S. Marks, loc.cit., p 7-22.
[13] General Electric Company home page, http://www.gmev.com.
[14] U.S. Department of Energy, 19th Annual Report to Congress
for FY 1995, DOE/EE-0108 states that in 194 transportation
petroleum consumption was 16.4 million barrels per day]
[15] P. Gordon and H.W. Richardson, The Case Against Electric-
Vehicle Mandates in California, Policy Study 189, Reason Founda-
tion, Los Angeles, 1995.
[16] See also: V. Bevc, Effect of the Electric Car on the En-
vironment and Energy Supply, The National Regulatory Research In-
stitute Quarterly Bulletin, 16, 1, March 1955, pp. 21--26.
