# Daniel P. Duffy

Daniel P. Duffy, P.E., writes frequently on the topics of landfills and the environment.

Construction

# Look Before You Leap

Many popular sayings are polar opposites of each other. “Look before you leap” is the exact opposite of “He who hesitates is lost.” However, a successful earthwork contractor must do both simultaneously. They must avoid the hidden dangers that can lurk below ground at any job site. They must also

Energy

# Use and Chemical Composition of Turbine Lubricants

Lubricants are materials that reduce friction by increasing the smoothness of moving surfaces in contact. All solids have surfaces with imperfections and roughness. These irregularities lead to increased friction and associated heat generation. By covering these imperfections in a viscous material or slippery liquid, friction is reduced and the moving

Water

# Successful Water Leak Detection and Audit Methods

Every drop of clean water is precious. Unfortunately, 30–50% of water is lost through aging infrastructure. And lost water equals lost revenue to the water service supplier. Water is lost through leaks and cracks in pipes and their fit­tings. Since most infrastructure is underground, it is virtually impossible to visually

Construction

# Estimating Earthwork Volumes

Formulas and methods for determining the volumes and areas of regular shapes and surfaces go back at least as far as ancient Greece. Pythagoras and other mathematicians determined those formulas that are still used to calculate the volumes of spheres and pyramids, as well as the areas of curve conic

Energy

# Smooth Operator

Lubricants are materials that reduce friction by increasing the smoothness of moving surfaces in contact. All solids have surfaces with imperfections and roughness. These irregularities lead to increased friction and associated heat generation. By covering these imperfections in a viscous material or slippery liquid, friction is reduced and the moving

Energy

# Testing the Limits

There is a problem with having backup gene­rators. The problem is that the operator may not know if the generator is capable of meeting necessary power demands in an emergency situation. What is needed is a device that allows for the testing of a simulated electrical load. Load banks are

Construction

# Keep on Trucking

Wheel wash systems are often one of the least recognized landfill structures for ensuring safety, health, and environmental protection. But they are far from being the least important—not that any landfill protective system is unimportant. For a minor capital investment and minimal operating costs, landfill owners and operators can achieve

Water

# Swimming in Profits, Not Drowning in Losses

Every drop of clean water is precious. Unfortunately, 30–50% of water is lost through aging infrastructure. And lost water equals lost revenue to the water service supplier. Water is lost through leaks and cracks in pipes and their fit­tings. Since most infrastructure is underground, it is virtually impossible to visually

Energy

# Pumps Operations in the Building Envelope

Water flows downhill. Nothing could be more simple. Getting water to the top floor of an urban skyscraper is a bit more difficult. Mere gravity flow or even accumulated static pressure head aren’t sufficient to accomplish this task. Pumps are obviously needed. But what kinds of pumps are used in

Construction

# Benefits of Training Operators With Simulators

Engineers don’t usually have the opportunity to actually operate the earthmoving equipment being used to turn their designs into reality. But any engineer with field experience can’t help but respect the operators of these machines. These are complicated, sophisticated pieces of equipment that make high demands on the skill and