Friday, May 16, 2014

Geotech Lab tips

Chart:
- Profile - should be a continuous line or curve
- Profile - do not use Trendline (Layout Analysis tab); this feature is not intended for our type of Labs. Use Chart types from Design Type tab.
- When you produce datapoints for your chart please use and leave Excel formulas so we can see how you obtained them
- Axis title and labels should be on the same side if possible
Format:
 - When preparing a table for a chart please keep it formatted, e.g., borders, headings, column names etc. Points will be deducted in the "Format and clear organization of the entire document and its parts" line
- Equations as ∑ _(i=1)^n  γ_i Z_i = γ_1 Z_1 + γ_2 Z_2 + γ_3 Z_3….+ γ_n Z_n  are not in any accepted notations and are not intelligible. Notations as σ(v) = Y(1)Z(1) + Y(2)Z(2) +Y(3)Z(3) are slightly better but still, have ambiguity, and may not be understood properly by a person distant from this specific lab and lecture.
- Use named cells
Memo:
- Keep Memo language formal; avoid words "like", "kind", "us engineers",
- Grammar - write Memo in a text processor and Copy-Paste into Excel text box. Excel does not have the spell check capability!
- If you decide to report key equations in Memo please report factors used, e.g., F = ma, where F is force, m is mass and a is acceleration
Units:
- When establishing a new data column please indicate units
- When you apply multiplication or division operator there's a good chance your units will change!
Calculations:
- Don't round intermediate results
Specific Weight (or Unit Weight) of water is 62.4 lb/cu.ft. (changes with temperature) 
General feedback:
- Please read the Lab instructions and the lecture materials before the Lab, come prepared!
- Don't wait to submit  until 09:50 when many other students may overload the server and you may not be able to submit successfully
- Charts have a random place on a chart Quest
- When reporting units, please avoid extraneous characters, e.g., (psf_)

Wednesday, May 7, 2014

IAQ and Pollution labs

A few notes about the IAQ lab and the upcoming water pollution lab.

IAQ:
- This lab was probably the most lopsided so far.  For many people, one mistake in this lab had a domino effect on the rest of the results.  If the rubric has that a value is "correct", it unfortunately does not leave room for partial credit, even if I can trace your work back to the error.

- Many people either mistyped or mis-converted the total heating gain from 280 kBTU/hr, should have been 280000 BTU/hr

- Many people mis-converted the electricity consumed by the chiller by using the BTU to watt-hr given.  However, the Ecooling has units of BTU/hr, and EER has units of BTU/watt-hr, so Ecooling/EER has units of (BTU/hr)*(watt*hr/BTU), or watt*hr/hr or just watt.  The instructions asked for kwatt*hr/hr, which required dividing by 1000.

- There seemed to be some confusion with the flow rates.  Put simply, Qe must always equal Qv.  The equation on the first page that Qv+Qr=Qe+Qr indicates this; if you subtract Qr from both sides of the equation, you're left with Qv=Qe.  Thinking about it physically, if if Qv was > Qe, there space would be pressurized, and if Qv were < Qe, it would be under vacuum.  Since we never want either of these, Qv and Qe will always be equal.  For question 3, the CO2 concentration should have decreased exponentially with increasing ventilation flow rate.


Water pollution lab due this week:
- Please make the memo a sheet in your workbook, formatted in the same way as previous memos, and answer all of the questions as described in the rubric.

- Format section: this is a more important section this time, please remember that your name and date should still be on each page.  On a similar note, organization is extremely important.  Each piece that is on the rubric should be clearly labeled in your document.

- Units are vitally important for this lab.  Make sure you clearly label all the conversions you make and label every result

- During lab, there were a lot of problems with entering the formulas into Excel.  Here's a couple features of your results to make sure you're on the right track:

  1. The peak concentration should be about 10^-2, variable to the time step you use and different between Pottstown and Norristown, 
  2. The rise and fall of the concentration should have about the same slope - if it is steeper on the upslope than the downslope, you've got a calculation error
  3. Both Norristown and Pottstown concentrations should peak and return to virtually zero in the time specified
Again, please let us know if you have any questions!

-Anita