CFP2: IMCC'98 Int. Manufacturing Conf., Singapore
mpeongsk@leonis.nus.sg (Ong Soh Khim)
22 Jun 1997 07:12:13 GMT
SECOND ANNOUNCEMENT & CALL FOR PAPERS
IMCC'98
THE EIGHTH INTERNATIONAL MANUFACTURING CONFERENCE
MAY 11, 12 & 13, 1998
SINGAPORE
Organised jointly by
National University of Singapore, Singapore
Warwick University, United Kingdom
The Hong Kong Polytechnic University, Hong Kong
Nanjing University of Aeronautics & Astronautics, China
National Natural Science Foundation of China, China
Chinese Society of Metal Cutting for University, China
_____________________________________________________________________
INTRODUCTION
The objective of the conference is to provide an opportunity for experts
in the modern manufacturing fields from all over the world to exchange
ideas and experiences. The event comprises a four-stream conference
presenting the results of the latest research in manufacturing
engineering world-wide. This includes the most recent developments in the
areas of advanced materials processing.
Subject Areas
The programme will consist of keynote papers and contributed papers
covering the following subjects:
A. Conventional and Non-Conventional Machining
Mechanics of machining, machinability
Machining of ceramic/composite materials
Tooling equipment and materials
B. Automation
CNC, CAD/CAM, FMS, CIM
Robotics
Automated assembly, inspection
Imaging and vision system
C. Manufacturing System
Design for manufacture
Manufacturing management & information systems
Quality and reliability management
Product engineering
Business process re-engineering
D. Advanced Manufacturing Processes
Forming/casting processes for conventional and new materials
Modelling of manufacturing processes
Expert system in processing
Rapid prototyping
_____________________________________________________________________
ABSTRACT AND PAPER SUBMISSION
Prospective authors are requested to send an abstract (about 300 words)
of their proposed contribution before 30 June 1997. English is the official
language of the conference. Instruction for paper preparation will be sent to
those authors whose abstract gain provisional acceptance. Completed
manuscripts will be required before 31 October 1997. It is a condition under
the acceptance of a paper for presentation at the conference, that the author
or, in the case of joint authorship, one of the authors will present the paper
in person. It is recommended to submit abstracts by electronic mail (ASCII
text) to
mpeongsk@nus.sg
or else by fax or mail (2 copies) to the following address:
Conference Secretariat, IMCC'98
Faculty of Engineering, Dean's office
National University of Singapore
10 Kent Ridge Crescent
Singapore 119260, SINGAPORE
Fax. No: (65) 777 3847
DATES TO REMEMBER
Deadline for Abstract: 30 June 1997
Notification of Abstract Acceptance: 31 July 1997
Deadline for Completed Manuscript: 31 October 1997
VENUE
The conference will be held in the campus of the National University of
Singapore, Singapore.
REGISTRATION
The registration fee per delegate is US$300. The fee includes proceedings,
banquet and reception.
One to two days post-conference tours to Penang (Malaysia), Bali (Indonesia)
and Phuket will be conducted. Accompanying person tour and technical trips
will be announced in due course.
The travel agent appointed for the conference will assist participants to
book rooms at tourist class hotels, and make arrangements concerning visa
and passport.
_____________________________________________________________________
CONFERENCE COMMITTEES
Conference Co-Chairmen:
Prof. A.Y.C. Nee
National University of Singapore, Singapore
Prof. W.B. Lee
The Hong Kong Polytechnic University, H.K.
Prof. S.K. Bhattacharyya
Warwick University, U.K.
Prof. J.Y. Zhu
Nanjing University of Aeronautics & Astronautics (NUAA), China
Honorary Advisors:
Prof. M. Wang, NUAA, China
Prof. W.S. Lau, Hong Kong Technical College, H.K.
International Advisory Committee
Dr. T.C. Lee, The Hong Kong Polytechnic University, H.K.
(Secretary)
Prof. R.Y. Chen, Huazhong University of Science and Technology, China
Prof. Q.X. Yu, BeijingUniversity of Technology, China
Prof. Z.J. Yuan, Harbin Institute of Technology, China
Prof. Z.H. Zhou, South China University of Technology, China
Organising Committee
Dr. S.K. Ong, National University of Singapore, Singapore
(Secretary)
Dr. N. He, NUAA, China
A/Prof. M. Rahman Dr. J.Y.H. Fuh Dr. A.S. Kumar
Dr. K.S. Lee Dr. X.P. Li Dr. H.T. Loh
Dr. M. Mannan Dr. Y.S. Wong Dr. Y.F. Zhang
National University of Singapore, Singapore
For further information, please write to
Conference Secretariat, IMCC'98
Faculty of Engineering, Dean's office
National University of Singapore
10 Kent Ridge Crescent
Singapore 119260, SINGAPORE
Tel. No: (65) 772 2142
Fax. No: (65) 777 3847
Email address: mpeongsk@nus.sg
_____________________________________________________________________
PROVISIONAL REGISTRATION FORM
IMCC'98
The Eighth International Manufacturing Conference
If you are considering to attend the conference, or wish to remain on
the mailing list, please complete and return this form.
I wish to (please tick as appropriate)
remain on the mailing list submit an abstract
attend the conference attend with spouse
Abstract/paper category:
A B C D
I wish to participate in a 2-3 days post-conference tour to
Penang, Malaysia
Bali, Indonesia
Phuket
Title: _________________________________________________________
________________________________________________________________
________________________________________________________________
Surname: (Prof./Dr./Mr./Ms.)
________________________________________________________________
Other names: ___________________________________________________
Organisation: __________________________________________________
Position: ______________________________________________________
Office Address: ________________________________________________
________________________________________________________________
________________________________________________________________
Email Address: _________________________________________________
Tel: ___________________ FAX:____________________
Re: Stop SI! Part I
gnygaard@crosby.ndak.net (Gene Nygaard)
Mon, 23 Jun 1997 04:45:21 GMT
Mr. Shead is up to his old tricks again--posting his weird treatises
to a number of newsgroups. I don't know why he does it; I've never
seen him post any responses to anyone who points out any of the
numerous fallacies in his arguments.
Even after a number of people gave Shead good answers to his "What's
(lbm) and (lbf)?" postings, he's still maintaining the ludicrous
position of his earlier postings that pounds mass don't even exist
(my comments on the specific points he made follow).
"Donald G. Shead" wrote:
>Stop SI! Part I
>Before we waste any more time on it, we’ve got to realize that the Metric
>(SI) System is confusing the important differences between Force, Weight
>and Mass!
SI helps make the distinction more clear. It is the use of strange
systems of measurement such as the one which uses pounds as the name
of the unit of mass and the same name, pounds, for the unit of force
which cause much of the confusion.
>Most people don’t know the difference, and don’t really know how important
>these differences are. They leave such distinction to scientific people,
>thrusting that they know, and will do the right thing.
"Thrusting"--you've really got pounds-force ingrained on your mind,
don't you? I am, however, coming to the conclusion you are right
about people not knowing the difference, after reading some of the
attempts to explain this on various newsgroup postings (not just
yours), and on some web pages and American encyclopedias, etc. These
explanations are often riddled with misinformation, and cannot
possibly clear up the confusion.
>Back a couple of hundred years ago, a well meaning group of scientists and
>high ranking officials decided to do something to consolidate the many
>different systems of weights and measures that were then being used to
>carry on the international trading of goods. They decided to start over
>with all new standards which would be based on the (tens) decimal system.
Okay so far, except this wasn't the first decimal system ever used.
>Essentially what they did was as follows:
>For their *Unit measure* of Length, they chose an all new ‘meter’, which
>was based on a ‘real measure’ of the length of a quadrant extending from
>the equator through paris to the North Pole.
Just the feature that makes many in aviation and polar exploration and
shipping think the nautical mile is such a wonderful unit, something
to hang onto even in places where metric units are normally used. A
kilometer is to a centigrade as a nautical mile is to a minute of arc.
(However, though grads and grades are one of the options for trig
functions on most modern scientific calculators, these angles have
never really caught on very much. The International System of Units
is maintained and updated by the international bodies established
under the Metre Convention, or Treaty of the Meter, of which the
United States was one of the original signers way back in 1875. These
organizations have decided the old Babylonian sexagesimal measures of
angles are so ingrained that these have been labeled as acceptable for
use with SI, but grads have not been so accepted.)
>For their *Unit measure* of Matter, they chose the ‘kilogram’,
>which was a french unit of weight.
The kilogram wasn't a French unit of weight before the metric system
was created. The old French 'livre' was like all the other various
pounds used throughout Europe and elsewhere (for English pounds, we
still use the abbreviation lb for the Latin root of livre, libra).
You forgot to explain how the litre was originally supposed to be
related to length, and how it has been again since 1964.
>They decided to call it a Unit of Mass; which they attempted to make
>equivalent to the amount of matter (the weight?) of a ‘liter’ of water.
An interesting sidelight is that in 1790 (when development of the
metric system was starting in France) the first U.S. Secretary of
State, Thomas Jefferson, proposed to the House of Representatives a
decimal system based on the foot. In this system, a cubic foot would
be a unit of volume called a bushel. A bushel of water would weigh
(have a mass of) 1 kental, equal to 10 stones or 100 pounds or 1000
ounces. Since an inch would be 1/10 foot, and its cube would be
1/1000 of a foot, each cubic inch of water would weigh one ounce
(unlike our current fluid ounces for a couple of different units of
volume, Jefferson's ounce wouldn't have had this additional
ambiguity--in his 'metric' system the 'metre' would have been this
volume of one cubic inch). An ounce of 22 karat silver would have the
value of one dollar (the American decimal money system had already
been adopted a few years before Jefferson's report). See the full
report at
http://ourworld.compuserve.com/Gene_Nygaard/t_jeff.htm
>For their Unit measure of Time passage they *kept* the second,
> and other related time periods.
>They proceeded to construct permanent Standards ~ metalic prototypes ~ for
>both the meter, and the kilogram. With some modifications these Standards,
>kept in Sevres France, are still the standards in use today. The trouble
>is that the kilogram of mass has become commonly known as a weight. Not
>just by ordinary people who see it simply as a “weight”, but also by
>scientists in general.
Just what do you think the various national standards for the "pound
troy" and the "pound avoirdupois" were at the time? They were similar
hunks of metal, kept in London or Washington or wherever.
And what do you suppose the definition of the pound is today? We no
longer have independent standards--not since way back in 1893 in the
United States, for example. The standard for pounds is now exactly
the same hunk of platinum-iridium alloy which defines the kilogram,
just as a specified exact fraction of it (0.45359237 kg for the
avoirdupois pound, or 0.3732417216 for the troy pound).
When the national standards laboratories of the countries using
English units in 1959 got together to agree on common definitions,
they defined the pound avoirdupois as a unit of mass, equal to
0.45359237 times the mass of the international prototype kilogram.
Don't you think all these metrologists from the United States, Canada,
the United Kingdom, Australia, New Zealand, Australia, South Africa
and probably a few other countries knew what they were doing? Don't
you think they knew the difference between mass and force?
In one specific English system of units, the pseudo-gravitional one
which uses slugs for mass and pounds for force, pounds-mass are not
part of the system per se. But they are part of the broader
metasystem--they are used to define the pounds-force which are base
units in that system. A pound force is 4.4482216152605 newtons, a
pound mass of 0.45359237 kg multiplied by an arbitrary, exact
acceleration of gravity of 9.80665 m/s^2.
Of course, with respect to the metre, it has gone through a couple of
official redefinitions since the metal prototype, and since 1983 it
has been defined as the distance light travels in a vacuum in
1/299792458 second.
The kilogram is and always has been a "unit of weight"--what it should
not be in proper SI usage is a unit of force. More on the meaning of
weight below.
>Periodically it has been necessary to issue reminders that the kilogram is
>a unit of mass, *not* weight. While the kilogram has a weight equal to
>9.804 newtons, it is a UNIT in that the quotient of this weight divided by
>the acceleration due to gravity (9.804 meters/sec^2) is equal to UNITY!
A kilogram somewhere will weigh (exert a force of) 9.804 N, but the
standard acceleration of gravity used for about a century or so at
least is 9.80665 m/s^2. However, weight does also mean mass, and in
that sense of the word weight kilograms are proper units to measure
this quantity.
The use of the kilogram as a unit of force did become popular in some
of the cgs and mks predecessors of the International System. It is
only since the SI was adopted in 1960 that the use of the
kilogram-force was officially deprecated, and that's why occasional
reminders have been issued since then. Once again, it is the
International System that is bringing clarity to the confusion of the
various old English systems of units, and the old metric systems as
well.
>Despite the periodic reminders, and the metric unit for force and weight
>(the Newton), many of the specifications written for metric (SI) units
>still use mass and weight as synonyms. The difficulties of writing clear,
>unambiguous specifications is compounded when such definitely different
>meanings are not clearly understood and/or stated.
The unit is the 'newton" -- not capitalized in the English language.
Now, this is a good time to get into the meaning of the ambiguous
terms such as "weight" and "to weigh." Weight does indeed often mean
mass, and "to weigh" means "to have a mass of" or "to determine the
mass of" and things like that, as well as the corresponding definitons
as the force due to the acceleration of gravity and the measurement of
that force, or other broader definitions including other kinds of
force.
These mass definitions are ancient and traditional definitions of
these words. It makes more sense to insist that the professionals who
intend these words to apply only in their force definitions make clear
that they are using units of force, than it does to expect the general
public to change the long-standing mass-related definitions of these
words.
Pounds have been around for a couple of millennia at least, and they
are based on other even more ancient measurement systems. But it is
only in the last three centuries that they have come to be used as
units of force, since the pioneering efforts of people such as Robert
Hooke and Isaac Newton in the late 1600s.
Prior to that time, "weight" was ALWAYS measured with balances of
various sorts--double pan balances, single pans with steelyards, beam
balances, etc. The important thing about this is that all of these
measure mass, not force (they do need some force to make them work,
but how much force that is cannot be determined from them directly
without also measuring acceleration).
Spring scales, which do measure force rather than mass, couldn't have
come into use before Hooke's Law was enunciated in 1678, and Newton
explained much of this further in his Laws of Motion, set out in his
1687 Principia Mathematica. Of course, other devices used to measure
force, such as load cells, are of much more recent invention than that
even.
Since the only devices used to measure "pounds" or any other unit of
weight before the late 1600s measured mass, and words such as "weigh"
and "weight" were used long before then, it is clear to me that the
mass-related definitions of weight are of long standing. Consider,
for example, all the times 'weight' and similar words are used in the
King James translation of the Bible, published in 1611. In this work,
if weight doesn't mean mass, it is used figuratively for one of life's
burdens.
Not only did these early weighing devices measure mass, but that was
exactly what most people wanted them to measure. When people buy a
pound of butter or an ounce of gold, they don't expect the amount they
receive to depend upon their location. These are definitely not units
of force, and furthermore they should not be such. To top things off
in a confusing hodgepodge of systems, it takes the mass of exactly 14
7/12 of these ounces used to measure gold to make one the mass of one
of the pounds used to measure butter. How in the world can Mr. Shead
think that using these units can reduce confusion in any way?
What I've said here, of course, doesn't mean that there weren't
situations before the late 1600s in which the force which these
weights exerted wasn't what people were really interested in. I'm
sure you can find many examples of this; somebody must have wondered
how hard he had to pull to draw a longbow, for example. That is one
reason that the same words came to be used for both mass and for
force. Nobody had any way to measure force, but objects of the same
mass do exert pretty much the same force anywhere on the surface of
the earth, within the precision of most measurements then or now.
In advocating the use of pounds, the ambiguity of the multiples and
subdivisions of pounds cannot be separated from the issue either.
With ounces you not only have the ambiguity as to whether force (278.0
mN for the avoirupois ounce) or mass is being measured, but if it is
mass the ambiguity as to whether it is the avoirdupois ounce of 28.35
g or the troy ounce of 31.10 g. You also have an additional ambiguity
with the word ounce also being used for two other common units of
volume-- a fluid ounce of 29.57 ml in the U.S., or of 28.41 ml
wherever ounces are used in the rest of the world.
When it comes to multiples of pounds, the hundredweight would seem
fairly straightforward--that is, until you figure out that the
incomprehensible Brits think that 'hundred' is written in digits as
'112.' Even in North America, this weird variation is used for some
purposes, at least in the long tons which are multiples of this
hundredweight. Just one more strike against the use of pounds.
Going further up the ladder of confusing units we come to the tons,
which might be units of either force or of mass, and for each of these
a multiple of either pounds (two different values) or of kilograms.
But not only that, but they are also used for dozens of different
units of volume, energy, power, etc. How many strikes do the English
units get, anyway?
In the English units, we not only have various scientific systems we
use for defining compound units such as pressure and energy, which use
pounds as the units of mass or as the units of force or both. We also
use 'system' to describe various 'systems of weights': avoirdupois,
troy, apothecaries'. I have never seen the troy or apothecaries'
systems (the troy system with different subdivisions between the grain
and the ounce) used to measure force; they are always units of mass,
normally called 'weight.'
>Metric proponents, who may or may not recognize the importance of
>distinguishing mass from force and weight are also adding to the confusion
>by insisting that if they can’t have metric units only on commercial
>packaging, then dual units must be used. Thus a package labled in ounces
>of *weight*, must also show equivalent grams of *mass*.
There you go again, making the erroneous assumption that since what is
placed on the label is the "net weight" that this means that it is a
unit of force. The ounces or pounds on the packages you will find in
your supermarket are not units of force. They are units of mass.
This "net weight" is properly expressed in grams, and to express it in
newtons would be flat-out wrong. And I do maintain that this use of
the word "weight" is quite proper as well, even if mass is the
quantity being measured.
If a government inspector comes into a manufacturer or a retailer to
test the accuracy of the measurements expressed on these labels or of
the scales used to measure these commodities, this will be done by
by measuring the mass of the contents on a balance or by testing the
scale by measuring known masses on it. There is no calculation of the
force involved at any time during this testing.
Even with the International System, the ambiguous nature of words such
as "weight" are an impediment to the clear understanding of these
concepts. But with SI, you do have a clear separation of the units
for the measurement of force and the units for the measurement of
mass, and that helps in specifying what is being referred to.
With SI, you do have some lingering problems with ambiguity of the
kilogram, which was used as a unit of force as well as a unit of mass
in some of the metric systems which preceded SI. But the trend is
towards increased, proper use of SI, and the ambiguity of the kilogram
is decreasing.
But at least we are fortunate that there are very few people like Mr.
Shead who'd like to add to the confusion by using newtons-mass in the
grocery store!
On the other hand, of the various English systems the one which uses
pounds as the units of force and pounds as the units of mass is the
oldest one, and it is probably the one used most often today. There
are several other newer systems which have been devised to try to
reduce this ambiguity, such as the one which uses pounds for mass and
poundals for force. But in that system, and in the one which you seem
to be under the misapprehension that all English-unit measurements are
made in, which uses slugs as the units of mass and pounds as the units
of force, the biggest problem is that whichever type of pound you
decide to use in your system, the other type of pound is still in
broad, general use (at least in the one island in a metric world, not
so much any more outside of the United States).
>END Part I.
>Donald Shead Chaplin, CT, USA
Good grief! I hope this doesn't mean there's a part II to follow.
Haven't we exhausted Mr. Shead's store of misinformation yet?
Gene Nygaard
***************************************************
# At the present time, however, the metrical system
# is the only system known that has the ghost of a
# chance of being adopted universally by the world.
# -- Alexander Graham Bell,1906
Re: Stop SI! Part I
gnygaard@crosby.ndak.net (Gene Nygaard)
Mon, 23 Jun 1997 04:45:21 GMT
Mr. Shead is up to his old tricks again--posting his weird treatises
to a number of newsgroups. I don't know why he does it; I've never
seen him post any responses to anyone who points out any of the
numerous fallacies in his arguments.
Even after a number of people gave Shead good answers to his "What's
(lbm) and (lbf)?" postings, he's still maintaining the ludicrous
position of his earlier postings that pounds mass don't even exist
(my comments on the specific points he made follow).
"Donald G. Shead" wrote:
>Stop SI! Part I
>Before we waste any more time on it, we’ve got to realize that the Metric
>(SI) System is confusing the important differences between Force, Weight
>and Mass!
SI helps make the distinction more clear. It is the use of strange
systems of measurement such as the one which uses pounds as the name
of the unit of mass and the same name, pounds, for the unit of force
which cause much of the confusion.
>Most people don’t know the difference, and don’t really know how important
>these differences are. They leave such distinction to scientific people,
>thrusting that they know, and will do the right thing.
"Thrusting"--you've really got pounds-force ingrained on your mind,
don't you? I am, however, coming to the conclusion you are right
about people not knowing the difference, after reading some of the
attempts to explain this on various newsgroup postings (not just
yours), and on some web pages and American encyclopedias, etc. These
explanations are often riddled with misinformation, and cannot
possibly clear up the confusion.
>Back a couple of hundred years ago, a well meaning group of scientists and
>high ranking officials decided to do something to consolidate the many
>different systems of weights and measures that were then being used to
>carry on the international trading of goods. They decided to start over
>with all new standards which would be based on the (tens) decimal system.
Okay so far, except this wasn't the first decimal system ever used.
>Essentially what they did was as follows:
>For their *Unit measure* of Length, they chose an all new ‘meter’, which
>was based on a ‘real measure’ of the length of a quadrant extending from
>the equator through paris to the North Pole.
Just the feature that makes many in aviation and polar exploration and
shipping think the nautical mile is such a wonderful unit, something
to hang onto even in places where metric units are normally used. A
kilometer is to a centigrade as a nautical mile is to a minute of arc.
(However, though grads and grades are one of the options for trig
functions on most modern scientific calculators, these angles have
never really caught on very much. The International System of Units
is maintained and updated by the international bodies established
under the Metre Convention, or Treaty of the Meter, of which the
United States was one of the original signers way back in 1875. These
organizations have decided the old Babylonian sexagesimal measures of
angles are so ingrained that these have been labeled as acceptable for
use with SI, but grads have not been so accepted.)
>For their *Unit measure* of Matter, they chose the ‘kilogram’,
>which was a french unit of weight.
The kilogram wasn't a French unit of weight before the metric system
was created. The old French 'livre' was like all the other various
pounds used throughout Europe and elsewhere (for English pounds, we
still use the abbreviation lb for the Latin root of livre, libra).
You forgot to explain how the litre was originally supposed to be
related to length, and how it has been again since 1964.
>They decided to call it a Unit of Mass; which they attempted to make
>equivalent to the amount of matter (the weight?) of a ‘liter’ of water.
An interesting sidelight is that in 1790 (when development of the
metric system was starting in France) the first U.S. Secretary of
State, Thomas Jefferson, proposed to the House of Representatives a
decimal system based on the foot. In this system, a cubic foot would
be a unit of volume called a bushel. A bushel of water would weigh
(have a mass of) 1 kental, equal to 10 stones or 100 pounds or 1000
ounces. Since an inch would be 1/10 foot, and its cube would be
1/1000 of a foot, each cubic inch of water would weigh one ounce
(unlike our current fluid ounces for a couple of different units of
volume, Jefferson's ounce wouldn't have had this additional
ambiguity--in his 'metric' system the 'metre' would have been this
volume of one cubic inch). An ounce of 22 karat silver would have the
value of one dollar (the American decimal money system had already
been adopted a few years before Jefferson's report). See the full
report at
http://ourworld.compuserve.com/Gene_Nygaard/t_jeff.htm
>For their Unit measure of Time passage they *kept* the second,
> and other related time periods.
>They proceeded to construct permanent Standards ~ metalic prototypes ~ for
>both the meter, and the kilogram. With some modifications these Standards,
>kept in Sevres France, are still the standards in use today. The trouble
>is that the kilogram of mass has become commonly known as a weight. Not
>just by ordinary people who see it simply as a “weight”, but also by
>scientists in general.
Just what do you think the various national standards for the "pound
troy" and the "pound avoirdupois" were at the time? They were similar
hunks of metal, kept in London or Washington or wherever.
And what do you suppose the definition of the pound is today? We no
longer have independent standards--not since way back in 1893 in the
United States, for example. The standard for pounds is now exactly
the same hunk of platinum-iridium alloy which defines the kilogram,
just as a specified exact fraction of it (0.45359237 kg for the
avoirdupois pound, or 0.3732417216 for the troy pound).
When the national standards laboratories of the countries using
English units in 1959 got together to agree on common definitions,
they defined the pound avoirdupois as a unit of mass, equal to
0.45359237 times the mass of the international prototype kilogram.
Don't you think all these metrologists from the United States, Canada,
the United Kingdom, Australia, New Zealand, Australia, South Africa
and probably a few other countries knew what they were doing? Don't
you think they knew the difference between mass and force?
In one specific English system of units, the pseudo-gravitional one
which uses slugs for mass and pounds for force, pounds-mass are not
part of the system per se. But they are part of the broader
metasystem--they are used to define the pounds-force which are base
units in that system. A pound force is 4.4482216152605 newtons, a
pound mass of 0.45359237 kg multiplied by an arbitrary, exact
acceleration of gravity of 9.80665 m/s^2.
Of course, with respect to the metre, it has gone through a couple of
official redefinitions since the metal prototype, and since 1983 it
has been defined as the distance light travels in a vacuum in
1/299792458 second.
The kilogram is and always has been a "unit of weight"--what it should
not be in proper SI usage is a unit of force. More on the meaning of
weight below.
>Periodically it has been necessary to issue reminders that the kilogram is
>a unit of mass, *not* weight. While the kilogram has a weight equal to
>9.804 newtons, it is a UNIT in that the quotient of this weight divided by
>the acceleration due to gravity (9.804 meters/sec^2) is equal to UNITY!
A kilogram somewhere will weigh (exert a force of) 9.804 N, but the
standard acceleration of gravity used for about a century or so at
least is 9.80665 m/s^2. However, weight does also mean mass, and in
that sense of the word weight kilograms are proper units to measure
this quantity.
The use of the kilogram as a unit of force did become popular in some
of the cgs and mks predecessors of the International System. It is
only since the SI was adopted in 1960 that the use of the
kilogram-force was officially deprecated, and that's why occasional
reminders have been issued since then. Once again, it is the
International System that is bringing clarity to the confusion of the
various old English systems of units, and the old metric systems as
well.
>Despite the periodic reminders, and the metric unit for force and weight
>(the Newton), many of the specifications written for metric (SI) units
>still use mass and weight as synonyms. The difficulties of writing clear,
>unambiguous specifications is compounded when such definitely different
>meanings are not clearly understood and/or stated.
The unit is the 'newton" -- not capitalized in the English language.
Now, this is a good time to get into the meaning of the ambiguous
terms such as "weight" and "to weigh." Weight does indeed often mean
mass, and "to weigh" means "to have a mass of" or "to determine the
mass of" and things like that, as well as the corresponding definitons
as the force due to the acceleration of gravity and the measurement of
that force, or other broader definitions including other kinds of
force.
These mass definitions are ancient and traditional definitions of
these words. It makes more sense to insist that the professionals who
intend these words to apply only in their force definitions make clear
that they are using units of force, than it does to expect the general
public to change the long-standing mass-related definitions of these
words.
Pounds have been around for a couple of millennia at least, and they
are based on other even more ancient measurement systems. But it is
only in the last three centuries that they have come to be used as
units of force, since the pioneering efforts of people such as Robert
Hooke and Isaac Newton in the late 1600s.
Prior to that time, "weight" was ALWAYS measured with balances of
various sorts--double pan balances, single pans with steelyards, beam
balances, etc. The important thing about this is that all of these
measure mass, not force (they do need some force to make them work,
but how much force that is cannot be determined from them directly
without also measuring acceleration).
Spring scales, which do measure force rather than mass, couldn't have
come into use before Hooke's Law was enunciated in 1678, and Newton
explained much of this further in his Laws of Motion, set out in his
1687 Principia Mathematica. Of course, other devices used to measure
force, such as load cells, are of much more recent invention than that
even.
Since the only devices used to measure "pounds" or any other unit of
weight before the late 1600s measured mass, and words such as "weigh"
and "weight" were used long before then, it is clear to me that the
mass-related definitions of weight are of long standing. Consider,
for example, all the times 'weight' and similar words are used in the
King James translation of the Bible, published in 1611. In this work,
if weight doesn't mean mass, it is used figuratively for one of life's
burdens.
Not only did these early weighing devices measure mass, but that was
exactly what most people wanted them to measure. When people buy a
pound of butter or an ounce of gold, they don't expect the amount they
receive to depend upon their location. These are definitely not units
of force, and furthermore they should not be such. To top things off
in a confusing hodgepodge of systems, it takes the mass of exactly 14
7/12 of these ounces used to measure gold to make one the mass of one
of the pounds used to measure butter. How in the world can Mr. Shead
think that using these units can reduce confusion in any way?
What I've said here, of course, doesn't mean that there weren't
situations before the late 1600s in which the force which these
weights exerted wasn't what people were really interested in. I'm
sure you can find many examples of this; somebody must have wondered
how hard he had to pull to draw a longbow, for example. That is one
reason that the same words came to be used for both mass and for
force. Nobody had any way to measure force, but objects of the same
mass do exert pretty much the same force anywhere on the surface of
the earth, within the precision of most measurements then or now.
In advocating the use of pounds, the ambiguity of the multiples and
subdivisions of pounds cannot be separated from the issue either.
With ounces you not only have the ambiguity as to whether force (278.0
mN for the avoirupois ounce) or mass is being measured, but if it is
mass the ambiguity as to whether it is the avoirdupois ounce of 28.35
g or the troy ounce of 31.10 g. You also have an additional ambiguity
with the word ounce also being used for two other common units of
volume-- a fluid ounce of 29.57 ml in the U.S., or of 28.41 ml
wherever ounces are used in the rest of the world.
When it comes to multiples of pounds, the hundredweight would seem
fairly straightforward--that is, until you figure out that the
incomprehensible Brits think that 'hundred' is written in digits as
'112.' Even in North America, this weird variation is used for some
purposes, at least in the long tons which are multiples of this
hundredweight. Just one more strike against the use of pounds.
Going further up the ladder of confusing units we come to the tons,
which might be units of either force or of mass, and for each of these
a multiple of either pounds (two different values) or of kilograms.
But not only that, but they are also used for dozens of different
units of volume, energy, power, etc. How many strikes do the English
units get, anyway?
In the English units, we not only have various scientific systems we
use for defining compound units such as pressure and energy, which use
pounds as the units of mass or as the units of force or both. We also
use 'system' to describe various 'systems of weights': avoirdupois,
troy, apothecaries'. I have never seen the troy or apothecaries'
systems (the troy system with different subdivisions between the grain
and the ounce) used to measure force; they are always units of mass,
normally called 'weight.'
>Metric proponents, who may or may not recognize the importance of
>distinguishing mass from force and weight are also adding to the confusion
>by insisting that if they can’t have metric units only on commercial
>packaging, then dual units must be used. Thus a package labled in ounces
>of *weight*, must also show equivalent grams of *mass*.
There you go again, making the erroneous assumption that since what is
placed on the label is the "net weight" that this means that it is a
unit of force. The ounces or pounds on the packages you will find in
your supermarket are not units of force. They are units of mass.
This "net weight" is properly expressed in grams, and to express it in
newtons would be flat-out wrong. And I do maintain that this use of
the word "weight" is quite proper as well, even if mass is the
quantity being measured.
If a government inspector comes into a manufacturer or a retailer to
test the accuracy of the measurements expressed on these labels or of
the scales used to measure these commodities, this will be done by
by measuring the mass of the contents on a balance or by testing the
scale by measuring known masses on it. There is no calculation of the
force involved at any time during this testing.
Even with the International System, the ambiguous nature of words such
as "weight" are an impediment to the clear understanding of these
concepts. But with SI, you do have a clear separation of the units
for the measurement of force and the units for the measurement of
mass, and that helps in specifying what is being referred to.
With SI, you do have some lingering problems with ambiguity of the
kilogram, which was used as a unit of force as well as a unit of mass
in some of the metric systems which preceded SI. But the trend is
towards increased, proper use of SI, and the ambiguity of the kilogram
is decreasing.
But at least we are fortunate that there are very few people like Mr.
Shead who'd like to add to the confusion by using newtons-mass in the
grocery store!
On the other hand, of the various English systems the one which uses
pounds as the units of force and pounds as the units of mass is the
oldest one, and it is probably the one used most often today. There
are several other newer systems which have been devised to try to
reduce this ambiguity, such as the one which uses pounds for mass and
poundals for force. But in that system, and in the one which you seem
to be under the misapprehension that all English-unit measurements are
made in, which uses slugs as the units of mass and pounds as the units
of force, the biggest problem is that whichever type of pound you
decide to use in your system, the other type of pound is still in
broad, general use (at least in the one island in a metric world, not
so much any more outside of the United States).
>END Part I.
>Donald Shead Chaplin, CT, USA
Good grief! I hope this doesn't mean there's a part II to follow.
Haven't we exhausted Mr. Shead's store of misinformation yet?
Gene Nygaard
***************************************************
# At the present time, however, the metrical system
# is the only system known that has the ghost of a
# chance of being adopted universally by the world.
# -- Alexander Graham Bell,1906
Colombian NR - Assistants Wanted Aug '97
PCL
Mon, 23 Jun 1997 11:30:53 -0700
Assistants are required for the following project, which will take place
this Summer. Anyone interested in helping should e-mail me at
tmd23@cam.ac.uk. Places are limited, and will be allocated on a first
come first served basis, with priority to those with ringing/banding
experience, or an interest in birds.
Thomas Donegan, Christ’s
Proposal for project: Birds of Tambito Nature Reserve, Colombia.
(Hoping to work through Project HERB with Fundacion PROSELVA and
Universidad
del Cauca, Popayan)
Dates:
I will arrive on the 11th August, travelling by plane from Bogota to
Popayan. Three days will be spent in Popayan, primarily at the Museo de
Historia Natural. This will allow familiarisation with the birds of the
region with Professor Negret’s skin collection.
On the 14th, we shall travel to the reserve, and will remain there until
the 15th September. One day will be spent at the reserve to finalise
details before starting the survey. A proportion of the remainder will
be spent under canvas, although accommodation will be required for the
whole of the period.
One further day will be spent in Popayan, compiling the results, and
submitting data to Prof. Negret.
Method
Tambito ranges in altitude from approximately 1000 to 2200 metres. It
shall be the aim to collect data in order to investigate the variation
in diversity and numbers of bird species, as well as any other
variations encountered as the altitude varies.
Six sites will be sampled, at the following altitudes: 1200m; 1400m;
1600m; 1800m; 2000m; 2200m. Areas below 1000m are to all intents and
purposes inaccessible. The altitudes closest to the reserve centre
(i.e. 1400, 1600) will first be studied, with the more remote ones done
later.
The sites used will follow the mule trails through the reserve as
closely as is possible, for ease of access.
It should take one day to reach a particular site, cut the net transects
and set up “base camp”. Four days will be spent at each site,
collecting as much data as the weather conditions allow.
“Base camp” will consist of a tent close to the mist-net transect.
Cooking will take place on an MSR gasoline heater from Uni. del Cauca
(donated by Proyecto Halcon). Paths will be cut using a machete (+
sharpening file), purchased in Popayan. Other equipment includes
binoculars, notebook, pens, torch, mosquito net, “A Guide to the Birds
of Colombia” (Hilty; Brown), nets, rings, measuring equipment,
wet-weather clothing, camera and sleeping bag.
Following methodology described by Salaman (1994b), up to ten nets will
be deployed (not in a straight line or at standardised distances apart)
to exploit natural vegetation features (i.e. dense cover, treefall gaps,
etc.), established trails and topographical irregularities (i.e. ridge
tops). This will significantly reduce two important biases; net shyness
(a tendency to avoid recapture) and net avoidance (individuals that
actively avoid net contact).
Net sites will be selected on the basis of experience and intuition to
maximise net captures and minimise habitat disturbance. Fixed nets will
be positioned between 0.5 and 3.0 metres. Canopy nets will not be used
as in the past they have not proved worthwhile (Salaman 1994b). Mist
netted birds will be processed and data noted in the following order:
i) Identified to species
ii) Metal numbered ring
iii) Age and sex determined (plumage, brood patch or clocacal
protuberance),
iv) Moult examination (body, wing and tail) and scored,
v) Biometrics measured: body mass, closed wing chord (flat), wing span,
body length, tail length (from skin surface of central rectrices to
longest rectrix), head length (inc. bill), bill length, tarsus length,
following procedures in Svensson (1992).
vi) Time the bird was caught to nearest 30 minutes,
vii) Net in which the bird was caught.
For re-captured birds, the time, net site and ring number/colours will
be noted. Photographs of each species trapped (at various angles), will
be taken and catalogued. Each day's mist netting shall be documented,
with the following details:
i) Location, habitat, co ordinates, altitude,
ii) Date and number of net hours,
iii) Number of nets and sizes used.
Planning of fieldwork considers the welfare of captured birds as
essential.
Nets will be checked on a continuous basis (i.e. 45 to 90 minutes).
Outputs
Any casualties will be submitted to the Museum for Professor Negret’s
use.
The results will be analysed using various correlation techniques.
Mark, release, recapture calculations will be made if viable numbers of
banded birds are refound. Data will also be supplied to Dr. Mark
Mulligan and Mr. Paul Salaman for use in the HERB project. A checklist
of the reserve will be produced, incorporating data which Professor
Negret and Mr. Salaman have collected in the past. A copy can be kept
there, and will also be sent to the publishers of “Where to Watch Birds
in South America” and the Tourist Office in Popayan. A full write-up
will also be submitted to IBIS or a similar journal for publication.
Conclusion
With the results obtained, more will be known about the reserve, which
will encourage tourism, especially by birders, increasing revenue for
the reserve and the surrounding area. Furthermore, the reserve will be
improved if a checklist can be made available. General information
obtained will increase knowledge of the effects of altitude on species
diversity, which can be used by scientists in future research.
CALL FOR PAPERS - EOEI '97
Nader Nada
23 Jun 1997 11:44:02 GMT
International Conference
On
Earth Observation & Environmental Information
(EOEI ‘97)
Alexandria, Egypt
October 13 - 16, 1997
OBJECTIVES:
The International Conference on Earth Observation and Environmental
Information (EOEI’97) will be devoted to presenting and exploring
international scientific and technical advances and innovative
contributions in the fields of : Remote Sensing, Geographical Information
Systems (GIS), Earth Observation, Data Management, Information
Infrastructure, Scientific Investigations, Training and Education in three
areas identified below. The conference will bring together researchers,
developers, educators, analysts and users, who utilize Earth Observation
and Environmental Information in the study of:
1- Oceans and Coastal Processes;
2- Water Resources;
3- Land Use / Land Vegetation Cover Change.
CALL FOR PAPERS
Contributions are solicited for oral or poster presentations.
Contributions should focus on the three research themes (oceans and
coastal processes; water resources; land use/land vegetation cover
change). Authors must submit a title and abstract of about 500 words for
review by the Technical Program Committee not later than June 15, 1997.
Authors will be notified of the acceptance of their contributions by July
15, 1997. The full paper version of the accepted abstracts may be
submitted to the conference (not mandatory). The full paper proceedings
will be mailed to the registered attendees after the conference. In the
context of the three themes listed above, appropriate contributions
include but are not limited to:
1. Earth Observation
Platforms,
Instruments
2. Data Management and Information Systems
Distributed Database Management Systems,
Geographical Information Systems,
Software Tools for Earth Science,
Internet Applications,
Networking and Data Distribution
Image Processing
3. Earth System Science
Process Studies,
Modeling Studies.
4. Education and Outreach
Formal Education,
Informal Education.
Deadlines
Submission of Extended Abstracts, June 30, 1997. (extended date)
Submission of Tutorial or Workshop Proposals, June 30, 1997.
Notification of Acceptance of Papers for Oral or Poster Presentation,
July 15, 1997.
Registration for Exhibits, July 15, 1997.
Submission of Camera-ready Extended Abstracts, August 15, 1997.
Authors / Attendees Pre-registration, August 15, 1997.
Home Pages
http : //www.frcu.eun.eg/www/conference/aast.html
http : //www.ceosr.gmu.edu/news.html
Re: Stop SI! Part I
"Richard White (CS)"
Tue, 24 Jun 1997 17:03:15 -0400
On 24 Jun 1997, Dean Pentcheff wrote:
> So here's my challenge: name five situations that are likely to occur
> in conventional daily life where the mass/weight distinction matters.
> Exclude cases like accurate airplane navigation (or, for that matter,
> nuclear warhead targeting!) where people certainly are affected, but
> without personal involvement. Navigation systems engineers worry
> about it, but airplane passengers don't need to.
Sidebar: In all the airplane navigating I've done as a pilot (some of it
even accurately), I've not yet been concerned about the weight/mass of
anything. Weight and balance calculations don't have anything to do with
navigation in the kinds of airplanes I fly, so perhaps I am ignorant of
what navigation systems engineers worry about. What would that be?
> So, aside from the (not insignificant) intellectual pleasure of
> drawing the mass/weight distinction, why should non-technical people
> care?
I was going to say that in hockey, which I play in a local recreational
league, the goaltender is quite concerned about the 1/2 mv^2 of that hard
little black rubber puck on an interception trajectory with his body, but
he probably doesn't think about it in those terms. He just says, "Ow,
that was a hard shot." Either that or "nya, nya, you missed me."
Maybe a better example is a car skidding on smooth ice (in winter in
Chicago of course). But then again, maybe the driver isn't thinking in
terms of his car's 1/2 mv^2 but rather how much it's going to cost him
when all that mass comes to rest against some other mass.
OK, how about this. In skydiving (my other favorite sport), the terminal
velocity of a jumper in freefall (the steady state velocity earthward) is
directly related to weight, not mass. When the aerodynamic drag (measured
in pounds) on the body exactly equals the weight of the body (also
measured in pounds), the acceleration is zero. Some very light skydivers
wear weight belts, similar to scuba divers, to equalize their fall rate
with the other jumpers in the formation. Heavier jumpers wear baggier
jumpsuits that increase drag, thereby enabling them to fall slower.
Though perhaps not considered "conventional daily life", he would have a
different terminal velocity on mars or venus where his weight and
aerodynamic drag are different, but his mass is the same.
Alright, let me have one more chance. A frisbee seems to fly better if it
has a little more mass, assuming the extra mass is distributed nearer the
perimeter. Paper airplanes seem to fly farther if they have some extra
mass such as a penny taped near the center of lift. Do these examples
count? How about a hammer? More mass drives the nail farther each swing.
Am I even coming close here?
I guess I can't imagine why non-technical people should care about the
distinction between mass and weight.
Never mind. Good question, though.
Happy times upon you, Richard.
