Geoscience Reference
In-Depth Information
• Doubling time
• Insect pest dispersal
• Mountain streamlow
• PCB dumping
• Wastewater treatment
• Water treatment
• Soil remediation
• Public health
• Water volume
• Thermal radiation exchange
Though individual learning style is important in choosing a career as an environmental profes-
sional, again we stress that generalized education is the key ingredient in the mix that produces the
fully educated environmental professional. Based on the list above, it can be seen that, along with
an education in the basic and applied sciences of mathematics, natural science, and behavioral sci-
ence (which are applied to the solution of technological, biological, and behavioral problems), an
education in engineering and technology is a must. Topics such as applied mechanics, properties of
materials, electrical circuits and machines, fire science hydraulics, principles of engineering design,
and computer science fall into this category.
In this chapter, we concentrate on applied mechanics and, in particular, forces and the resolution
of forces. Why? Because many environmental incidents or accidents and subsequent damage to the
environment and injuries to people and animals are caused by forces being of too great a magnitude
for a particular machine, material, or structure. To inspect systems, devices, or products to ensure
their safety, environmental professionals must account for the forces that act or might act on them.
Environmental professionals must also account for forces from objects that may act on the human
body (an area of focus that is often overlooked).
Important areas that are part of or that interface with applied mechanics are the properties of
materials and engineering design considerations. (Fire science hydraulics and electrical circuits, as
well as safety concerns associated with both of these important areas are addressed separately later
in this text.) We do not discuss all of the environmental engineering aspects related to these areas
in this text—this is not an engineering text. Instead, we look at a few fundamental engineering
concepts and their applications to environmental professions.
11.2 RESOLUTION OF FORCES
In the environmental and occupational health aspects of environmental engineering, we tend to
focus our attention on those forces that are likely to cause failure or damage to some device or
system, resulting in an occurrence that is likely to produce secondary and tertiary damage to other
devices or systems and harm to individuals. Typically, large forces are more likely to cause failure
or damage than small ones. Environmental engineers must understand force and how a force acts
on a body, particularly (1) the direction of force, (2) point of application (location) of force, (3) the
area over which force acts, (4) the distribution or concentration of forces that act on bodies, and (5)
how essential these elements are in evaluating the strength of materials. For example, a 40-lb force
applied to the edge of a sheet of plastic and parallel to it probably will not break it. If a sledgeham-
mer strikes the center of the sheet with the same force, the plastic will probably break. A sheet metal
panel of the same size undergoing the same force will not break.
Practice tells us that different materials have different strength properties. Striking a plastic
panel will probably cause it to break, whereas striking a sheet metal panel will cause a dent. The
strength of a material and its ability to deform are directly related to the force applied. Important
physical, mechanical, and other properties of materials include the following:
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