Episode 115 — Bearings

August 21, 2016 Jeff Shelton 1 Comment

Carmen and Jeff discuss mechanical bearings in this episode of The Engineering Commons podcast.

Carmen has a pretty good sense of his navigational bearing, but is less knowledgeable about mechanical bearings.
U.S. interstate highways are numbered with even numbered roads going primarily east-west, and odd numbered roads passing mostly north-south.
Differences between skateboards and longboards are noted by Carmen.
A distinction is made between rotational and linear-motion bearings.
Non-contact fluid bearings may be of the hydrostatic or hydrodynamic variety.
Magnetic bearings allow for higher relative motion velocities, albeit at a higher cost than other non-contact bearings.
Carmen mentions the Laser Interferometer Gravitational-Wave Observatory (LIGO) experiment that detects cosmic gravitational waves.
A flexure bearing allows relative motion to take place through bending of the bearing element.
The lid of a Tic Tac box provides an example of a flexure bearing.
The two most commons types of bearings are journal bearings and rolling-element bearings.
Oilite is a porous bronze alloy impregnated with an oil lubricant.
Engineers must consider the tradeoffs between using oil or grease when lubricating a bearing.
A starting point for choosing a plain bearing is calculating a PV value (pdf).
A pillow block may be used to attach a bearing to a component lacking room for a bearing bore.
A ball bearing consists of an inner race, an outer race, balls, and a cage.
Assembling a ball bearing is fairly straightforward once you’ve seen how it’s done.
Ball bearings may be ordered with either shields or seals to limit the amount of contamination able to reach the rolling elements.
Bearing quality can vary significantly between manufacturers.
A variety of roller bearings can be used to support greater radial and axial loads than can be handled by a ball bearing.
It’s important to apply the correct amount of preload to angular contact bearings.

Thanks to WikiMedia Commons for use of the photo titled “Ball Bearing 2.” Opening music by John Trimble, and concluding theme by Paul Stevenson.

Podcast Episode

Episode 114 — Driven Electrons

August 4, 2016 Jeff Shelton 1 Comment

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Brian leads our discussion of electric vehicles in this episode of The Engineering Commons podcast.

Carmen notes that a single resting electron has a mass of 9.11 x 10^-31 kilograms.
Brian suggests some form of positronic vehicular propulsion might be possible, although radiation issues would make it impractical for most earthbound applications.
One of the currently available electric hybrids is the Cheverolt Volt.
Adam notes the Volt’s drive arrangement is similar to that of a diesel electric locomotive.
Electric vehicles were first invented back in the mid-19th century.
Although gas vehicles were less popular than either steam or electric vehicles in 1900, the gas engine was clearly established as the market leader by the 1930s.
At one point, Ford suggested it might build a nuclear-powered passenger vehicle, the Ford Nucleon.
General Motor’s entry in the electric vehicle field, the EV1, was made famous by the 2006 documentary Who Killed the Electric Car?
Although not a “pure” electric vehicle, the Toyota Prius has been a popular electric hybrid.
The first highway-capable electric vehicle mass produced for sale in the United States was the Tesla Roadster.
Smaller gas pump nozzle diameters were introduced as automobiles transitioned from leaded to unleaded gas.
Differing interfaces exist for charging electric vehicles.
A common connector for charging electrical vehicles in North America is defined by the SAE 1772 standard.
Tesla is building its Gigafactory 1 to produce lithium-ion batteries in high volume.
A recent death in an auto-piloted Tesla will challenge the emerging self-driving vehicle industry.
Some states are levying “green car” taxes to make up for lost gas tax revenues.
Tesla has recently purchased solar power provider SolarCity.
The U.S. Department of Energy provides a webpage that estimates emissions, on a state-by-state basis, for the electrical power used to operate electric and hybrid vehicles.

Thanks to Wikimedia Commons for use of the photo titled “General Motors EV1.” Opening music by John Trimble, and concluding theme by Paul Stevenson.

Podcast Episode

Episode 113 — Chemical Engineering

July 23, 2016 Jeff Shelton 1 Comment

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Chris Welch joins Adam, Brian, Carmen, and Jeff to talk about the field of chemical engineering.

Jeff believes in unicorns, even though he’s never seen one!
From his childhood, Jeff recalls watching a DuPont film about “Better Living Through Chemistry.”
Our guest for this episode is Chris Welch, a chemical engineer from New Brunswick, Canada, who works in the water treatment industry.
Branches of chemistry include (but are not limited to): physical chemistry, organic chemistry, and analytic chemistry.
Biological scrubbing uses bacteria to remove Hydrogen Sulfide (and volatile organic compounds) from a gas stream.
Chemical engineers concentrate on facilitating chemical reactions, thereby allowing for large scale production, while chemists focus on developing innovative materials and processes.
In the mid-1900s, it was possible to buy kids’ chemistry sets containing cyanide, uranium, and ammonium nitrate.
Chemical engineers sometimes make use of process simulators, such as Aspen Plus, ChemCad, and PRO/II.
Thermal management is an important part of controlling many chemical processes.
Plant shutdowns can be very expensive, especially when the shutdown is unexpected.
A chemical reactor is a vessel that contains (and facilitates) a chemical reaction.
Solids are removed from a liquid through sedimentation in a clarifier.
In Canada, licensed engineers carry a “P.Eng.” designation.
Our guest is a drummer in local pipe band.
Listners can reach Chris via email: cwelch -+= at =+- unb dot ca.

Thanks to Grey World for use of the photo titled “colourful chemicals.” Opening music by John Trimble, and concluding theme by Paul Stevenson.

The Engineering Commons Podcast

Episode 115 — Bearings

Episode 114 — Driven Electrons

Episode 113 — Chemical Engineering

Practical insights for the engineering crowd