Agriculture Reference
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Figure 5.5 Decision force field
driven predominantly by one or a
few factors. For example, if
mortality or serious disease will
increase, medical efficacy holds
primacy over environmental,
financial, and even legal
considerations (a). Legality is
complex. At least ideally, the law
protects public safety, health, and
welfare (the three mandates of
the engineering profession). Thus,
it may embody aspects of the
other sectors (e.g., medical
beneficence, environmental
protection, cost accountability). If
medical efficacy is flexible and can
be achieved in a number of ways
but environmental impacts are
substantial, irreversible, and/or
widespread, the design will be
driven to be greener (b). Note that
in both diagrams, all of the factors
have some force; that is, the
factors are important, just not as
influential as the stronger factors.
Medical efficaciousness
Environmen t
Medical efficaciousness
Environmen t
The plot criteria are selected to provide an estimate of the comparative sus-
tainability of candidate products. It is important to tailor the criteria to the design
needs. In the case of Figure 5.7, this addresses primarily the toxic hazard and risk
of the substances: 8
Vapor pressure : a chemical property that tells us the potential of the chemical
to become airborne. The low end of the scale is 10 8 mmHg; the high end
is 10 2 mmHg and above.
Henry's law : tells us how the chemical partitions in air and water. Nonvolatile
substances have a value of 4
10 7 (unitless), moderate volatility is between
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