Great Engineers & Scientists

Roger Boisjoly was best known for warning Morton Thiokol, his employer, and NASA against the dangers of a part on the space shuttle Challenger. Morton Thiokol decided that the data was inconclusive. NASA launched the shuttle on January 28, 1986 and it exploded seconds later.

Boisjoly earned a mechanical engineering degree from the University of Massachusetts at Lowell. During his 27-year career in the aerospace industry, he worked on projects including lunar module life-support systems (LEMs), the moon vehicle, and solid rocket boosters (SRBs).

Faulty O-Ring Discovery

Six months before the shuttle exploded, Boisjoly wrote a memo to colleagues at Morton Thiokol. He explained that cold weather could cause the O-rings in the SRB to fail. His findings were based on an investigation of an SRB from a shuttle flight a year earlier. An O-Ring had failed in the 1985 launch when the temperature was 50° F.

A task force was created to examine the effect of cold temperatures on the boosters. The seals were found to stiffen and unseal in cold weather. If this happened at launch it would spell a certain death for the astronauts on board the shuttle.

Attempts to Prevent Disaster

The temperature fell below freezing the night before the Challenger launch. That night Boisjoly and four colleagues held a phone conference with NASA to discuss delaying the launch. He showed photo evidence of damage from the previous cold-temperature launch. The Morton Thiokol vice presidents in attendance decided the evidence was not conclusive. NASA decided to go ahead with the launch.

At the time, Morton Thiokol was discussing a new $1 billion contract with NASA. The Challenger launch had already been delayed twice; it is thought that another delay could put the company's contract in jeopardy.

Work Post-Disaster

After the Challenger disaster Boisjoly testified at a Presidential commission. He explained why he thought the O-rings had failed and provided copies of the memos he had sent six months earlier. He went on leave from Morton Thiokol and was eventually unemployed. He was told nobody could afford to hire a whistleblower. His colleagues turned against him and he said astronaut Sally Ride was the only one who supported him.

Eventually he began speaking to engineering students about workplace ethics. After leaving Morton Thiokol he donated six boxes of his personal papers and memos to Chapman University in Orange, California. He was awarded the Prize for Scientific Freedom and Responsibility by the American Association for the Advancement of Science.

Read more about the Challenger disaster on CR4.

Resources:

DC Bureau - Roger Boisjoly - The Conscience of Engineering

The New York Times - Roger Boisjoly, 73, Dies; Warned of Shuttle Danger [image]

NPR - Remembering Roger Boisjoly: He Tried To Stop Shuttle Challenger Launch

Wikipedia - Roger Boisjoly

Hydrology, hydrogeology, soil science, civil engineering, petroleum engineering, and chemical engineering all benefit from Henry Darcy's discoveries and innovations in fluid flow.

Darcy was born on June 10, 1803 and spent most of his life in France. He was educated in science and engineering at the L'Ecole Polytechnique. In 1823 he entered L'Ecole des Ponts et Chaussee's, or the school of bridges and roads.

He was employed by Le Corps des Ponts et Chaussées to support France's infrastructure. In 1828, one of his first assignments was to conduct a feasibility study of his town's public water supply. Darcy discovered that deep well drilling could not adequately support the town's water needs. He created a plan for a system to deliver water from a nearby spring using an aqueduct and reservoir system. It was gravity-driven, requiring no pumps or filters. A system was built based on his recommendation and was second only to Rome at its time (1840).

He later worked as Chief Director for Water and Pavements in Paris. He researched flow and friction loss in pipes, contributing to the Darcy-Weisbach equation for pipe flow. Darcy also worked to improve the design of the Pilot tube, a pressure instrument used to measure fluid flow velocity. Darcy modified the 17^th century design of Henri Pitot to a form still used today.

The discovery of Darcy's Law was found in Note D, an appendix of his book Les Fontaines Publiques de la Ville de Dijon (The Public Fountains of the City of Dijon), published in 1856. Through sand experiments he described the flow of fluid through porous media.

Henry Darcy had been in poor health for several years by the time his book was published. He died of pneumonia in Paris on January 3, 1858.

Resources:

Oklahoma State: Henry Darcy and His Law

Rutgers: Henry Darcy (1803-1858): Immortalised by his scientific legacy

Wikipedia: Henry Darcy [image]

Wikipedia: Pitot tube

Paolo Frisi was a leading authority on mathematics and science during the mid-18^th century in what is now Italy. Frisi worked with dynamics, physics, astronomy, mathematics, geodetics, hydrodynamics and electricity. He published a book, De moto diurno terrae, about the motion of the earth. He was the first to introduce the lightning conductor to Italy.

Education & Early Career

Frisi was born in Milan and educated at the Barnabite monastery. Appointed by the King of Sardinia, he became a professor of philosophy at Casale Novara. (He was removed from the institution because of a friendship with a liberal; part of his duties included being a preacher.) His other teaching positions included:

• Barnabite College of St. Alexander - professor of philosophy
• University of Pisa - professor of mathematics
• Palatine Schools at Milan - professor of mathematics

Contributions

A major accomplishment from his work with light and electricity was being the first to introduce the lightning conductor to Italy. At the time it was not always believed that lightning was an electrical phenomenon. Thus, metallic conductors would be unable to prevent damage caused by lightning. Early lightning rods were placed on the towers of churches and castles. Public tests were often conducted to prove the functionality of the lightning rods - and the laws of physics.

Frisi's work with astronomy was largely based on Newton's theory of gravitation. He wrote a memoir about his study of the motion of the earth, De moto diurno terrae. He studied the motion of the moon and physical causes for the shape and size of the earth.

Because of his studies of kinematics and hydraulics, Frisi was asked to draw up plans for a canal. In 1762 he published a work on hydraulics, Del modo di regolare i fiumi, e i torrentini (A treatise on rivers and torrents; with the method of regulating their course and channels). He created a plan for a canal between Milan and Pavia. It was built in 1819, using his plan, 35 years after his death.

In addition to his own studies, Frisi helped bring the contributions of Galileo, Cavalieri, Newton, and d'Alembert to a wider audience. His work in Latin was translated into French and English.

Resources:

Bertucci, Paola. "Public Opinion, Local Authorities, and the Reformation of Meteorology in Eighteent Century Italy."

Berzolari, Alberto Gigli. "Volta's Teaching in Como and Pavia: Moments of Academic Life Under All Flags."

Paolo Frisi

TODAYINSCI: Paolo Frisi

Wikipedia: Paolo Frisi

http://www.museobiassono.it/Italiano/index.php?page=/Italiano/schede/S08/index.html [image]

Education and Early Career

Roebling was born Johann August Röbling. He grew up in Mühlhausen, Prussia, learning to play musical instruments and received tutoring in mathematics and science. He later studied architecture, engineering, bridge and foundation construction, hydraulics, and languages. From 1825-1829 Roebling built military roads for the government

In 1831, Roebling left Prussia with one of his brothers. This was a time of political unrest in Prussia; the Napoleonic Wars had ended in 1815 leaving economic mobility difficult for engineers. The brothers purchased 1,582 acres in Pennsylvania. They farmed for about five years.

Roebling returned to engineering. Manifest Destiny was a dominant mode of thought in the 1840s and there were opportunities for him to work in river navigation and canal building. He became a Pennsylvania state engineer, surveying and supervising the construction of canals, locks, and dams.

He began producing wire rope to replace the hemp rope used to transport canal boats over the Allegheny Mountains via railroad car. He helped create the Allegheny Aqueduct and later a suspension bridge over the Monongahela River. Roebling went on to create other bridges in Trenton, New Jersey, and connecting Canada and the U.S. via the Niagara River.

The Cincinnati-Covington Bridge was built over the Ohio River in 1867 and was later renamed the John A. Roebling Suspension Bridge. At the time, it was the world's largest suspension bridge.

The Brooklyn Bridge

Completed in 1883, the Brooklyn Bridge had a main span of 1,595.5 feet, making it the longest suspension bridge in the world. The bridge was built to link Manhattan and Brooklyn. Its design boasted:

• Steel wire construction
• Stronger, longer, and larger than any other bridge at the time
• Roadways for vehicles
• Cable car transportation
• Elevated pedestrian promenade

Pressurized pneumatic caissons were sunk to depths of 44.5 feet (Brooklyn) and 78.5 feet (Manhattan) to provide a dry underwater space for workers to dig the bridge's foundations down to solid rock. Many workers suffered from the bends upon leaving the high-pressure atmosphere.

John Roebling's son Washington was permanently impaired by the bends as a result of his work on the Brooklyn Bridge. Washington's wife Emily actively supervised the construction after that time.

The Brooklyn Bridge opened in 1883 but John Roebling was unable to attend. He had died in 1869, shortly after construction began. His foot was crushed in an accident on site; he died of tetanus 24 days later.

Resources:

Great Buildings: John Augustus Roebling

The Library of Congress: Roebling and the Brooklyn Bridge

Wikipedia: John A. Roebling

http://blogs.princeton.edu/graphicarts/2008/09/designing_the_brooklyn_bridge.html [image]

This engineer worked on projects ranging from building thousands of miles of railroad to putting in place the infrastructure needed to complete the Panama Canal. Although John Frank Stevens did not actually dig the canal and locks, he helped set the stage for George Washington Goethals, who worked on those parts of the project.

Railroad Work

Stevens was born in Maine and completed his education in civil engineering in 1873. He moved to Minneapolis, MN and began surveying and building railroads. In 1886 Stevens worked for the Duluth, South Shore and Atlantic Railroad and built the line across the upper peninsula of Michigan.

He later worked for the Great Northern Railway and built over a thousand miles of railroad. Stevens helped discover a way through Marias Pass over the Continental Divide - a means of expanding the railroad through the Rocky Mountains without a tunnel. He made another discovery farther west; Stevens Pass, east of Everett, WA, was named for him.

Stevens built the original Cascade Tunnel at Stevens Pass. Construction of the Cascade Tunnel was completed in 1900. It was a single track railroad 2.63 miles long. The tunnel was electrified in 1909 to eliminate a smoke problem. A 1910 avalanche, the deadliest in U.S. history, killed 96 people. A longer and lower tunnel was built; the original Cascade Tunnel was abandoned in 1929.

Panama Canal

Stevens was appointed chief engineer to the Panama Canal project in 1905. Morale was low and successes were few when he entered the project. Stevens helped lay the groundwork that would help the project get started:

• Insisted workers be immunized against yellow fever (along with malaria it killed hundreds of workers per week).
• Introduced a food car to boost morale.
• Pushed to build a lock canal rather than one at sea-level.
• Built transportation infrastructure (railroads, warehouses, machine shops, and piers) and new communities.

Stevens' original agreement with President Theodore Roosevelt had been to "stick to the job until he could predict success or failure according to his own judgment". He resigned from the project in 1907, having turned it around from the "devil of a mess" left behind after the resignation of John F. Wallace, his predecessor. George Washington Goethals was appointed to complete the Panama Canal, including its actual construction.

Resources:

Balboa Circle Renamed to Honor Canal Engineer

PBS - American Experience - Biography: John Stevens

Wikipedia - Cascade Tunnel

Wikipedia - John Frank Stevens [image]

Arthur Casagrande moved from Austria to the U.S. in 1926 at age 24. He was a professor of soil mechanics who started the Soil Mechanics program at Harvard University and conducted research on soil classification, seepage through the earth, and shear strength. It's likely that the "A-Line" on the plasticity chart is named after him.

Casagrande earned a civil engineering degree from the Technische Hochschule in Vienna, Austria in 1924. He continued to work there after graduation as a full-time assistant in the hydraulics laboratory.

Researcher

Casagrande's first American appointment was to Massachusetts Institute of Technology (MIT) in 1926. He was a research assistant with the U.S. Bureau of public roads. His work focused on improving apparatus and techniques for soil testing. In 1929 he worked again in Vienna, Austria helping to set up a soil mechanics laboratory.

He made several fundamental contributions to the understanding of soil mechanics:

• Point pressure is induced during undrained shearing
• Significant differences in mechanical characteristics between undisturbed and remodeled clay
• Procedures for identifying the preconsolidation pressure in an overconsolidated soil
• Worked on Atterberg limits (it's possible the "A-line" on plasticity charts is named for Arthur)

Teacher

The Soil Mechanics program at Harvard University was started by Casagrande in 1932. It served as a model for other programs because it emphasized laboratory courses and included seepage as an inherent part of the curriculum. Casagrande was promoted to chief of soil mechanics and foundation engineering at Harvard in 1946.

Other Work

Casagrande consulted for the Army Corp of Engineers, helping them to understand soil mechanics for airfield construction. He trained about 400 army officers in the program.

He also participated in the design and construction of earth dams around the world. This was related to his research on seepage and soil liquefaction.

Casagrande organized the first International Conference on Soil Mechanics and Foundation Engineering in 1936. It helped legitimize his work in soil mechanics as an essential part of civil engineering.

Resources:

New York Times - Arthur Casagrande, Teacher And Innovator in Dam Design

Wikipedia - Arthur Casagrande

World Wide Web of Geotechnical Engineers - Arthur Casagrande

http://gsl.erdc.usace.army.mil/gl-history/Chap11.htm [image]