Daily GENERAL Mega-Thread [Aug 17 2017]

Daily GENERAL Mega-Thread [Aug 17 2017]

Welcome to /r/engineering's daily thread!

This thread is open to all questions, comments, and discussions, especially those things not usually permitted in normal posts:

  • Career advice questions
  • Job offer and job market discussions
  • Resume critiques
  • Office/management/employee topics
  • Questions about school/major choice/course electives (homework questions will be removed)
  • Discussions of current projects, including progress images
  • Pretty much anything you want to talk about that is engineering or job-related is fine provided you follow rules seven (7) and nine (9).

Submitted August 17, 2017 at 06:07AM by AutoModerator
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Daily GENERAL Mega-Thread [Aug 17 2017]

Electrical P.Eng

Electrical P.Eng

Hello Engineers,

I am soon graduating with a Bachelors of Engineering, and I am currently doing my internship. Where I work only one individual has his P.Eng, and he rarely has to use it in his work. My question is, what role does the P.Eng play for an Electrical Engineer?

In what line of work is a seal from an electrical engineer required? What documents would an electrical engineer typically seal?

Submitted August 17, 2017 at 12:34AM by marioo1182
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Electrical P.Eng

Any good equipment for measuring small hole dimensions?

Any good equipment for measuring small hole dimensions?

I'm working with very small (~0.25mm dia) round and shaped holes made with EDM/laser machines. I am currently using an Alicona machine to get their actual dimensions. I was wondering if anyone knows of other inspection machines available that can analyze the holes and give me their dimensions.

Submitted August 16, 2017 at 09:58PM by SumRegis
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Any good equipment for measuring small hole dimensions?

NTSB says “85th Percentile Rule” is No good?

NTSB says “85th Percentile Rule” is No good?

I just heard about this today from superspeedersRob on Youtube in this video: https://www.youtube.com/watch?v=kuxk9mNUVeE. Here's a link to the report Rob speaks about: http://ift.tt/2u13K8t.

The report says

Typically, speed limits are set by statute, but adjustments to statutory speed limits are generally based on the observed operating speeds for each road segment—specifically, the 85th percentile speed of free-flowing traffic. Raising speed limits to match the 85th percentile speed can result in unintended consequences. It may lead to higher operating speeds, and thus a higher 85th percentile speed. In general, there is not strong evidence that the 85th percentile speed within a given traffic flow equates to the speed with the lowest crash involvement rate for all road types. Alternative approaches and expert systems for setting speed limits are available, which incorporate factors such as crash history and the presence of vulnerable road users such as pedestrians.

Did something change since I was in school? My understanding from highway design was that the 85th percentile rule was the best way to set speed limits and the safest. The term "reasonable and prudent" has been stuck in my head for years from that class. It was never mentioned that it would cause a feedback loop where higher speed limits lead to higher 85th percentiles ad infinitum.

I've always been a fan of using the design speed for roads but was reasonably accepting of the 85th percentile method since we had to read the study that originally proposed it and listed its merits in school. Of course, I've never been a fan of arbitrary statutory limits.

Anyone know what's going on at the NTSB and why they decided the 85th percentile rule isn't sufficient anymore?

Submitted August 16, 2017 at 06:01PM by Goins2754
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NTSB says “85th Percentile Rule” is No good?