Take-Home Assessment – Comments

Some of you may wish to know how the class performed on the final Take Home Assessment. Here are some comments

The Process

• I graded all the essay questions myself – almost everyone was careful and received full credit
• I reviewed the “item analysis” provided by BbLearn.  It looks at the performance on each question to see if there problems because they were poorly written or possibly required material that was not presented in class.
  • As a result of that review I decided to add 8.2 points to each person’s raw score to make allowance for possible lack of clarity, although I found no questions that I felt were wrongly stated.
  • The result of this increase in the exam is reflected in the column –CAEE-201 TakeHomeAdj

Some comments on questions where there were difficulties.

• Learning after Graduation – It’s almost certain that you’re going to need to go on learning throughout your career as an engineer.  Many of you chose answers that indicated your thought there wouldn’t be much later learning.
• Heat Transfer Calculation – this was the same basic question as in Lab #1
• Nested IF Function – This was admittedly a difficult question, but it was directly based on the hydrology lab.  Learning to use this kind of logic will almost certainly be beneficial in your engineering career.
• Gas Concentrations – A key result of the IAQ lab was that you cannot have all things – low ozone and low CO2 merely by ventilating.
• Revit Type – Revit is BIM software.  When I Googled the word Revit the first entry stated that as I did in class.
• EER – EER is a ratio of BTU/Watt-Hour – It’s a measure of efficiency of an air conditioning system.  it is NOT dimensionless as it is used. 
• Kinetic Energy Calculation – The trick here was to refer to Prof. Dasaro’s lab, where the weight had to be converted into mass to perform the calculation.
• Member Weight Calculation – It’s surprising that so many had difficulty with this one.  You needed to calculate the volume and multiply by the density, being sure to watch the units of volume to work in either in^3 or ft^3.

Short Essay on Best or Worst Aspect of CAEE-201

I covered this in a separate post

Final Grades

The final grades have been submitted to Banner.  Below are some notes that may be of interest.

Percentages for Components

The percentages used for the components were:

• Assignments 43%
• Discussions 23%
• Attendance 16%
• Take Home Assessment 18%

Attendance

• Each student was allowed three “free” attendance misses without affecting your grade.

Discussion Grade

• The lowest discussion grade was not included in the calculation.

Laboratory Grades

• The lowest two laboratory grades were not included in the calculation
• Note that we dropped one additional lab grade beyond what was promised.  This was in recognition of the delayed return of labs.  It raised some student’s term grades significantly.

Letter Grades

• The assignment of a letter grade followed the syllabus.
• We rounded upwards

Grade Distribution

The grade distribution overall was:

Range	Count	Letter Grades
90-100	50	A’s
80-89	33	B’s
70-79	10	C’s
55-69	8	D’s
<55	1	F

 

Why a grade may have dropped from the “Cumulative Grade” shown during the term.

The cumulative grade during the term was a “running total” that did not include in calculations items that had not yet been graded, or turned in at all.  At the end of the term any missing grades (labs or discussions or the final assessment not submitted) turned to a zero and was included in the calculation of the term grade.

Student who turned in everything will probably have seen an increase in their term grade because the two lowest labs were dropped in that calculation, whereas only one was dropped in the “Cumulative Grade”.

Best and Worst Aspects of Course–Your Opinions

I’ve just completed grading the essay question that each of you completed on the exam.  I’m happy to say that all of you took it seriously and thus almost everyone received a “5 out of 5”.  Only a few people had entries that were too short or not read for grammar, thus losing portions of a point.  One or two, sadly, did not complete the question at all and thus received no points.

Since I use this question as a prime way of learning what’s good about the course and what needs improvement I keep a tally while grading of “Best” things and Worst things.  Here’s a summary of what I learned.

Choice of Best or Worst to Discuss

• 46 people chose to write exclusively about the Best
• No one chose to write exclusively about the Worst
• 48 chose to write about the best and worst

Best Aspects of the Course – by number of mentions

• The lectures – mostly for their variety and enthusiasm – 46
• Site Visits – 31
• Course helped solidify the student’s understanding or choice of major – 28
• Discussions – 22
• Variety of topics in the course – 21
• Well structured/balanced class –17
• Helpful TAs – 11
• There were quite a variety of aspects with fewer than 10 mentions including specific lecturers, specific labs, aspects of the administration

Worst (or problematic) Aspects of the course

• Delayed feedback/grading of the labs – 19
• This was a big change from prior years due to the lack of grading help.  I apologize to all once again.
• A variety of aspects with less than 10 mentions including: Discussions, lab instructions, dull lecturers, specific labs.

Some Statistics

• Average length of your essays – 254 words
• Longest essay – 455 words

To get a sense of your overall satisfaction with the course I rated each essay on a 1-to-7 scale with one being “intense dislike” and seven being “best course of the term” – a four being neutral.  Using that scale your rating was 5.9 out of 7 overall.  I will look at the course evaluations when you complete them to see how they match this rating.

Kinetic Energy Units–Final Assessment Calculation Question

Question

“Somewhat confused on my last question for the final in your CAEE-201 class.  It asks for kinetic energy in "( in ft lbs).  I assume this parentheses is off but not sure how to calculate KE without having a unit of time?:

Response

The units are correct if the weight (NOT mass) of the truck is given in lbs. Prof. Dasaro’s lecture notes on the tanker colliding with the bridge address this issue.

BbLearn Grading Status as of 12/5/2013 Noon

Attendance

All attendance records have been updated including your attendance at the final class meeting on 12/4/2013.  The attendance now includes the allowance for two missed lectures and one missed lab.  There were 29 possible events so everyone with 26 or more will see a 29 in the Attendance column.

Labs and Discussions

The graders are completing the discussion and lab grading..  By early next week you should see a grade for everything you’ve submitted including the Senior Design lab.

Cumulative Grade Calculation

As I stated in class, the cumulative grade currently shown in BbLearn could decrease when calculating the final course grade.  That is because at the moment what BbLearn shows does not include in the calculation any labs or discussions that you did not submit.  When calculating the final grade any missed discussion or lab will be assigned a “0” grade and will be included in the calculation.

Your lowest (e.g. one “0” for a missed lab) will be dropped in the final grade calculation. If you turn in all the labs your lowest grade will be dropped.

Senior Design–Identifying Information

Question:

“I have a question about the write-up format for the senior design presentations. The project description is in paragraph form, but what about the identifying information? Should I just include it as a list in the memo, or is there a particular format for including that information?”

Response:

It’s a good idea to present the identifying information as a list.  There are no specific requirements.

Week-8 Lab–Air Flow Rate

Question

Within the instructions for lab 8, there is an equation given to find the mass of the air, however only one of the two necessary parameters is given. The air density is given, but the volumetric flow rate, Qt, is not given and without it neither the mass nor Qt can be solved through the equation.

Response

There is sufficient information. The equation given addresses any volumetric flow rate.  If you look through the rest of the lab you’ll see several possible flow rates.  You use this equation to determine the mass flow rate in each case.

Attendance Grades & Overall Grade Calculation

I’ve brought the attendance grades up to date through week-8.  You should check the attendance score and other grades now rather than at the end of the term.

Notes on the grading:

• Attendance scores are “raw”.  At the end of the term I will make an allowance for one missed lab and two missed lectures – a total of three.  This will improve your attendance score in the final grade calculation.
• Discussion and Lab scores are already adjusted to drop the lowest score in calculating the running total.  HOWEVER.  If you didn’t turn in a lab or discussion that one isn’t included in the calculation during the term.  IT WILL be included as a “0” at the end of the term so your overall grade could decrease

Hints for HVAC lab

Memo for Revit Lab–Format

Question:

I have concern about Revit lab memo this week. Since the questions asking specify personal experience with Revit, can I write it in first person? DoI have to follow memo format like previous lab or just answer the questions?

Response:

Since this lab asks for a personal reaction it is acceptable to use “I” in your memo.  Otherwise be sure to keep the memo professional – avoid slang, check grammar and spelling etc.

Week-8–Rec Center Visit

Week-8 - Rec Center Tour - Lab Locations and Times

This week we’ll be touring the Rec Center AND having time in the lab to address the calculation assignment of the week.  You should plan to be involved the whole two hours of your lab period.

Note that we will meet outside the East entrance to the Papadakis Integrated Sciences Building (inside if raining).  Here’s a map showing where we’ll meet and where we’ll go.

Wear flat shoes (NOT heels) – we’ll walk on sensitive surfaces.

As was the case last week, if a few of you from section #61  wish to come in the morning during the #60 times there should be space since the afternoon lab is bigger than the morning lab.  If too many show up we'll have to turn away extras.

Time & Location

Lab	Last Name	Time	Location	2nd Hour
060	A-M	10:00	Papadakis ISB	GL-48
060	N-Z	10:00	GL-48	Papadakis ISB
061	A-K	12:00	Papadakis ISB	GL-48
061	L-Z	12:00	GL-48	Papadakis ISB

Lab memo help reminder- follow this format

Here are some guidelines from the previous lecture as a reminder about how to write a successful memo

Week-6 Lab–Site Visit Mention

Question:

“I am doing lab assignment6 - hydrology. I am little confused what relation to site visit is in memo sheet, since we have never actually visit the site. Could you explain that for me?”

Response:

You may ignore that issue.

You are correct to bring that to my attention.  In past we’ve schedule the hydrology lab during the same week that we visited the Rec Center.  This year that did not happen and I missed that in reviewing the assignment.

Lab 3 Feedback

- Write formulas you use on each question template (e.g., PE = 0.5 * m * v²), as per Lab PPT slide 7

- DO A “REALITY CHECK” on your answers- In Q8 if you get displacement x to b e a very large value, for example 210 inches, you should think about the physical significance and realize there might be an error (we understand the examples may be very hypothetical, but you should still ask if your answer makes sense)

- Things that are not limitations: The physical model of the collision, the fact that you were given lab data instead of measuring them yourself.

- Please avoid inserting symbols (arrows, etc.) unless it is in the equation at the top of your sheet. 

- Please continue to use appropriate significant figures. For example, do not write 13856.32 lb/in², where 0.02 lb/in² equals to stress caused by a weight of 0.32 oz laying on a 1 sq.inch surface. You will drastically overestimate the accuracy of your work, especially on a structure like the T-P Bridge pier. Scientific notation may mask an unrealistic computed value (e.g., 2.3E-22 lbs), so be careful, or use common notation with an appropriate rounding and sig figs.

-For the potential energy, you needed to consider that each of the two legs of a pier can absorb some of the impact of the tanker (multiply by two in question 3). For displacement of the bridge, the legs of the pier move together and therefore you should not have accounted for a factor of two there (Do not multiply by two in question 2, but consider in question 5 that Pyield is per pier). The words “per pier” or “for both piers” were explicitly stated in each question at the top of the sheet, question 6 asked for EACH pier. For question 7 do not account for factor of 2. For each question, you had to specify which approach was correct for that problem (not just write down both) and highlight your answer.

- ~25% of all errors are with UNIT CONVERSIONS! Please be careful when applying conversion factors.

Other feedback and general comments:

 - We understand that in some cases you will need to think about the problem.  These labs are not meant to be just plug-in exercises.

- If you do not have access to Excel or a computer, the CAD lab and Korman building have resources available. OpenOffice Calc will also work with the templates.

- If you have been working in groups, consider switching your group members each week since some of you are making the same mistakes from week to week. You MUST turn in your own original work. Do not reuse work from previous semesters of this course.

Revit Lab - Hints For the Lab

Below are the hints for the lab.

• Save your file to desktop in the cadlab to avoid losing it in your machine 
  • Email it to yourself, or use a flash drive, or DropBox
• Videos online are helpful if the text instructions aren't clear
• If you have only 3-4 letters in your last name - multiply by 20 to get the length of your wall.
• Make walls go to 2nd level 
  • set "property" before  drawing, but you can change later
• Remember to put on a dimension 
  • under the annotate menu
• Not all things in the videos are required for this lab

Answers to Several Questions About Revit

Questions: – From Previous Year, but still appropriate

1. Hello, I have one question about the Revit Lab. I followed the videos, made the Revit model and the output sheet. How do I convert the sheet to a PDF file from Rivet?
2. Also, we're supposed to submit the actual Rivet model, meaning we have to submit the actual file we made upon starting the Rivet videos? Just a little confused, hope you can clear that up thank you.

Response

#1 You need to “Print to PDF”.  On the machines in the lab there is a PDF printer installed – just choose it when you’re printing.

If you’re doing this on your own machine you’ll need to install a “PDF Printer”.  There are multiple free one available.  TechSupportAlert is a good recommendation source – Here’s their link to PDF Printers and tools.

#2 You are to submit three things for this assignment

• The actual Revit File
• The PDF of the “Sheet” that you’ve created
• The Word document defined in the assignment.

Lab-7– Revit –Times and Locations

Location

This week’s lab will again be located in the CAEE CadLab in CAT-167.  It’s on the ground floor in the Southeast corner of the building.  CAT is the building to the North of Ludlow (where the food trucks are located)  - Link to Google Maps

Time

Because there are only a limited number of computers in the lab we’re again splitting each section in half, so each comes for only 1 hour.  You may exchange with a student from another section, but except as noted below please do not come at a time different than the one to which you’re assigned.

Note that section 061 is much bigger than Section 060 so some students from 061 may come to the 060 times with a reasonable chance of finding a place.  Those officially in the section will have priority if we exceed the capacity of the room.

Section 060 10:00-12:00
A-M	10:00
N-Z	11:00
Section 061 12:00-2:00
A-K	12:00
L-Z	1:00

Revit

We’ll be using the program Revit in the lab.  You’re welcome to download it for your laptop for free from http://students.autodesk.com.

• It’s a 3GB download and a 5GB Install
• You’ll need to register with Autodesk
• It’s for Windows Machines only

Lab Week-5 Velocity Value

There is a conflict between the instructions and the “grading criteria” spreadsheet for what velocity to use for the river.

We will accept either the 1.6mph of the instructions or a velocity calculated as in the grading criteria sheet.  Since the TA’s mentioned the 1.6mph value in the session last Thursday that is the preferred value.

Some more memo help

Engineering Lab Memos - reposted from CAEE 201 Spring 2013

A sizable component of your engineering and academic career will be acquiring data and presenting your work.  There are many ways to present your work: laboratory reports, memos, executive summaries, professional letters, posters, and presentation formats.  Perfecting your business and engineering writing styles takes practice and matures over time.  Many times the documents that you produce may become legal documents, subject to future scrutiny should a problem arise.

Be sure to conduct your own search to locate good sources for writing examples.  I've included a few to get you started.

Here is a great source for writing laboratory reports, where the major sections are discussed: Abstract, Introduction, Procedures, Results and Discussion, Conclusions, and Appendices:
http://www.writing.engr.psu.edu/workbooks/laboratory.html

When writing business memos, always avoid the use of first person, casual tone and opinion.  You just need present the important data keeping in mind the purpose, details, limitations, and implications of your work.

For example: We took a tour of the Tacony-Palmyra Bridge and it was so fun to get hands-on experience and measure the strain gage distance for ourselves.

A better way to state the same activities: A site tour of the Tacony-Palymyra Bridge was conducted and field measurements were recorded to determine the strain gage distance.

Here is a great source for writing business memos:
http://owl.english.purdue.edu/owl/resource/590/04/

You can always get help here at Drexel by utilizing the Writing Center:
http://drexel.edu/engphil/about/DrexelWritingCenter/
http://drexel.edu/engphil/about/DrexelWritingCenter/workshops/

They also have various workshops you may register for during the various terms:
http://drexel.edu/engphil/about/DrexelWritingCenter/workshops/

Post-grading feedback Lab 2

Procedure:

- It was possible to see that location 1 gravel and location 2 mud have unsaturated and saturated 'sub-layers'

- Total Stress = [Unit weight of material in layer] * [Material Layer Thickness]

- Effective Stress = [Total Stress] - [Specific Weight of Water] * [Saturated Material Layer Thickness]

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[k1] .

- Reminder to use named cells

Memo:

- Keep Memo language formal, avoid "like", "kind", "us engineers",

- Grammar - write Memo in a text processor and Copy-Paste into Excel. 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 establish a new data column please indicate units

- When you apply multiplication or division operator there's a good chance your units will change! Example: Unit Weight [lb/ft³] * Layer Height [ft] = Stress [lb / ft²]

Calculations:

- Don't round intermediate results

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[k2] 

-- Reporting units, please avoid extraneous symbols, e.g., (psf_)

- Please check if your new suggestions repeat previous - don't re-submit. "Give us meaningful suggestions for improving this lab or CAEE-201". Many suggestions essentially say "Make the labs simpler"

---

 [k1]I took points off if they did not define their variables

 [k2]Rephrase this

Seeing The Graded File Returned by The TA

Several students have been unclear how to access the files that the TA’s have graded and returned via BbLearn.  Here are instructions that should help.

• Open the course in BbLearn
• Click on Grades in the left column
• Click on the title of assignment - e.g. "Week-3 Lab Structures"
• You’ll see the attached file in lower right under the small heading "File Name"
• Click on it to see it
• You can download it by clicking on the small icon with a downward arrow in top dark bar - 2nd from right.

Sketch of bridge for lab

For the bridge lab, the sketch can be combined for question 1 and 2 if you like. It can be done by hand and scanned in, drawn in paint, or using arrows pointing to a picture you took at the site, for example. It should be a rough drawing of the bridge section you looked at, with the dimensions you measured labelled on it. Here is a schematic from the bridge that might help- make sure you do your own.

Post-grading feedback Lab 1

1. Following the 1st Feedback Blog Entry will help avoid many errors for the Lab1.
2. Memo writing was graded generously  but you must improve your memo writing. The blog entry Memo Writing for Lab Reports contains suggestions for writing a good Memo. We will not be so generous on future assignments.
3. In the US Customary Unit System a pound (lb) is used as a unit of both mass and force. Please use correct one when making your calculations.
4. If you need to convert mass into force, you cannot use g = 9.81 m/s². What value of g in the US Customary Units ft/s²? It was in the 10/9 lecture.
5. EXCEL -- starting Lab2 all exercise calculations must be done with Excel by entering formulas into cells for example =C31+D32 instead of =4+5
6. A common mistake was forgetting to multiply the pipe length by the number of stories.
7. When presenting two or more charts (as it was in Q6 Lab1), please format your graphs so they are both the same size.
8. Bridges charts – a legend was not needed since just one subject is featured. An appropriate title is sufficient. Conversion factors have to be taken with max or +2 extra sig figs than the data with max sig figs.
9. Please watch significant figures. An extra sig fig maybe excused in this class but still it simply is not needed. Correct number of sig figs will be increasingly enforced.
10. If  you used rounded intermediate calculations to arrive at a final answers there may have been a loss in precision. It’s best to put rounded values in a separate cell and use the cells with formulas when calculating your final answer. Then round the final answer.
11. In our comments s f = sig figs
12. ROUND for integers made easy with num_digits set as a negative integer. From Excel help: "If num_digits is less than 0, the number is rounded to the left of the decimal point"

Discussions - Addressing Other Student’s Work

Question:

I am a student in your CAEE 201 class and I was wondering if the replies had to be done in the section you posted in. I was the first to post in my discipline, Environmental Engineering, so I was unsure if I was supposed to post a reply in the other disciplines or not. Please get back to me when you can.

 

Response:

The intention was that most students would include reactions/comments about other students’ work in their own post.  The following notes may be helpful:

• If you’re the first person to post in a section (e.g. Environmental Engineering), then you do not need to address any other student’s posts
• If you’re the second you only have to address the first – and so on up to the number required.  You only need to consider within your section.
• If you wish to make a comment attached to another person’s post that is fine, but please structure your own post to indicate to the grader that you’ve done so with names and sections so they can find that post easily.

Seeing Blog Summary in Firefox and Chrome

Recent versions of Firefox and Chrome can block the appearance of the box summarizing the blog on the home page of BbLearn.  IRT recently provided information on the simple fix for this problem.

Firefox recently made a change in it's security features and it is now blocking what it has been told is unsecured content.  This is the issue that is featured on the homepage of Learn of the left hand side.

Here's a video of me enabling it.
http://screencast.com/t/Wat6ROIw

Chrome will do a similar thing, but the shield is on the right hand side.

IE too, but it's a questions posed in yellow at the bottom of the screen and you have to answer the question such that unsecured content is allowed.

Lab 1 feedback from the TA's

1.       Due - 10 AM Thursday a week after the class, but also check with current Syllabus.

Excel:

2.       Named Variables - don't use spaces. Good practice -- capitalize 1st letter of a word, e.g. MyFirstName
3.       Troubles with Excel -- please refer to Excel help and tutorials; it is the best and most effective solution. You can also try the IRT MS Office training workshop.
4.       Remember, Excel is a computational software; it is designed to do computations for you.
5.       Excel allows leaving comments in cells - you can use this feature when you feel a comment may add clarification.
6.       Consult the Post-It-like notes and Instructions attached to question pages for grade tips.

Units and sig figs:

7.       Conversion factors column does not need formulas; it needs conversion factors which are constants. No real rule for conversion factors sig figs.
8.       Prof. Mitchell is OK with an extra sig fig. I encourage using a good judgment when deciding to have it or not, and not leaving an extra digit across the whole exercise.
9.       Units spelling -- refer to literature e.g. , NIST Handbook 44 - 2013 Edition, Appendix C - General Tables of Units of Measurement  OR NIST Special Publication 330, 2008 Edition. International System of Units (SI). Both are by National Institute of Standards and Technology, Washington, DC.
10.   Note:: Some questions have non-conforming unit notations, it is alright to correct them when Excel allows to.
11.   In Question 5 --  BTU/CF-DegF means Btu/ft³∙°F (and similar to it cells).

Memo:

12.   Writing Memo -- consult Prof. Mitchell's blog entry and the links he refers to.
13.   Memo subject -- "Meaningful phrase that announces the topic".
14.   Memos should have a professional tone. Limitations of the lab are not your own personal limitations or struggles but rather specific caveats related to assumptions you had to make in order to complete your calculations (ex: did you actually measure your shoulder width with a ruler?) See the earlier entry on the course blog for additional suggestions.
15. Some labs have specific questions that should be answered in Memo.

Misc.:

16.   If you do not have a laptop, please look at the lab prior to class time and come to the class session to ask your questions.
17. If your computer does not have MS Office -- it appears that it is OK to do it in OpenOffice (save as .xls or .xlsx file), or maybe use CADLab machines.

Conversion Factors and Methods

Conversion factors could be seen as universal constants. Some of them are exact, like 1 inch equals 25.4 mm. Most of them don't have an exact value but rather expressed as a decimal fraction with 4-8 sig figs which is enough for most engineering applications without reducing desired precision.In the lab we had to find several conversion factors. It may be OK and definitely convenient to google it, but for the lab Memo and for professional reports a google search is not a credible reference. I think the best source of reference materials such as conversion factors is a relevant industry's handbook. For HVACR it would be ASHRAE Handbook - Fundamentals. An electronic edition of it is available through Drexel libraries, but for this large class' convenience I also supply a link to the Chapter 38 image file on my Google Drive (page 1 and page 2). I hope the ASHRAE people won't be considering it as a serious breach of copyright. It can be cited as ASHRAE (2009), 2009 ASHRAE Handbook - Fundamentals (I-P Edition), Chapter 38 Units and Conversions, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. Another great reference would be ASTM/IEEESI-10-1997 Standard.The unit-factor method is a commonly used technique to convert a value from one system of units into another, or from one unit into another within the same system. Explore it more on KhanAcademy videos. Wikipedia article on it also is a good one on the unit-factor method (and of course we never refer to Wikipedia in memos and reports). Unit conversion is fundamental and essential to engineering disciplines!

References Style

ASCE recommends its authors to use Author-Date References.  I suggest that we adhere to this recommendation in the class.

Significant Figures and Rounding

The concept of significant figures (sig figs, s.f.) arises from the concept of physical measuring of a variable. Instruments we use have finite accuracy and reliability. For example, a desk ruler has least readable unit (least count) of 1 mm, while a common Vernier caliper can measure with accuracy of 0.02 mm. Thus the reasonably reliable length of a steel plate measured with the ruler could be 26 mm (two s.f.), while measured with the caliper would be 26.14 mm (four s.f.). If one has to add two measures, let's say a plate measured with a ruler and a plate measured with the caliper, the ±0.5 mm uncertainty of the first plate will dominate the uncertainty in length of the second plate ±0.01 mm. When that person reports the combined length of 52.14 mm he or she cannot defend the final precision up to 0.02 mm because the ruler's precision of 1 mm dominates. Side-note: some technicians and researchers state that many elementary measuring devices allow an (experienced) operator to estimate the measured value one figure beyond the instrument's least count. In our ruler example, we could estimate the plate's length as 26.1 or 26.2 mm (three s.f.)

Very often we have to use the measured values in various calculations which ordinarily give as answers with a long trail of decimals. While it is perfectly fine to carry the trails during a multi-step calculation, the final answer must be always rounded off and reported with a correct number of s.f. In other words, the accuracy of the final answer cannot exceed the accuracy of the least accurate measurements or data provided.  Four groups of different arithmetical "operations" have different rules of maintaining s.f. Those groups are Addition and Subtraction, Division and Multiplication, Logarithms and Antilogarithms, and Trigonometric functions.

Addition and subtraction can produce and answer with a higher or lesser s.f.

Division and multiplication results are limited by the data with least s.f. I have heard respected opinions that there's an exception to the division and multiplication rule. The opinion is based on the notion of fractional uncertainty: when an answer begins with a digit 1, the answer's accuracy would be preserved better if we maintain an extra s.f. than the original data with lowest s.f. I personally adhere to that opinion. However, I advice to proceed with caution - it appears that this "rule of 1" is not widely discussed and often omitted. Please consult relevant literature or specific industry's guidelines for further use.

In logarithm operations the mantissa determines the number of s.f.

For purpose of real life applications trig functions preserve the number of s.f. of the input variable.

A few words on rounding tie-breaks (when the "digit" we want to cut off is "exactly" 5, e.g. 26.145 or 26.14500 or 26.145000). Many disciplines use the round half up or round half away from zero rules. Both those rules are asymmetrical and lead to biases. In science the most accepted tie-breaking rule is round half to even. As per 09/25/2013 1900 the Wikipedia's relevant page has a correct explanation with an example.

My favorite intro text on s.f. with computational examples is Quantitative Chemical Analysis by Daniel C. Harris.

References:

ASTM Standard E29, 2008, "Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications," ASTM International, West Conshohocken, PA, 2008, DOI: 10.1520/E0029-08, www.astm.org.

Harris, D. C. (2007), Quantitative Chemical Analysis, 7 ed., 663 pp., W. H. Freeman, New York.

Michener, B.; Scarlata, C.; Hames, B. (2008). Rounding and Significant Figures: Laboratory Analytical Procedure (LAP). 7 pp.; NREL Report No. TP-510-42626. http://www.nrel.gov/biomass/pdfs/42626.pdf

About You

You may find it interesting to know the composition of the class.  Here’s the breakdown by college, major and year.

As expected, the majority of you are sophomores from the CAEE department, but there are a significant number of Business and Engineering Seniors and a sprinkling from other departments and colleges.

Memo Writing for Lab Reports

In past offerings of CAEE-201 the graders have commented repeatedly on how students have lost points in their lab reports because of poor understanding of what is expected in a Technical Report – we call it a “Memo” in most of our labs.  What follows is the description from “Lab Assignments” on appropriate Memo Writing.

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You will write many letters, proposals and reports throughout your career. In these labs we require a "memo" that in one page summarizes the key aspects of the lab. It's very important that you learn to write this kind of document well because you will be judged by your employer by HOW you say what you did as well as what you did - that's a reality. Here are two links that should help on writing good memos. There are many others available online or through your English instructors.

• The Content of A Technical Memo - PDF Document from Texas A&M giving good guidelines. Adapt it as appropriate.
• Language for a Technical Memo - WikiHow has good advice on appropriate language.

 

Keep in mind the following. The reader will want to know:

• Who did it
• What you did
• Why you did it
• When you did it
• Where you did it
• What tools/equipment/programs you used
• What you found
• What you conclude
• What uncertainties, reservations you have after completing the work
• What further work you would recommend (if any).

 

For language you can avoid most problems by:

• Write in "simple" language. Be direct and brief.
• Check grammar and spelling
• make use of language labs and other resources if English is not your native language
• Make use of MSWord's grammar and spelling checker - write there and paste the text into the memo
• Avoid colloquial or slang language

Your Work in CAEE-201–Requirements

The requirements for your work in this course spelled out in detail in the BbLearn pages addressing each.element.  This page summarizes that work.

Weekly Work

• Attendance

• We will take attendance at all lectures and lab sessions.  You will have a total of three “free” misses to account for illness or other reasons for missing the class.

• Discussions

• Post a “discussion” in BbLearn each Monday by the start of class addressing the week’s topic.

• Note that you’re to have read other student’s work and commented on it.

• Labs

• Go to the Thursday lab each week

• Download the lab from BbLearn and review it before the start of the lab session.  That lab session will be your only regular opportunity to meet with a TA to ask questions about the lab.

• The location and duration of the labs will vary through the term.  We’ll announce that week’s requirements in class. Some weeks we’ll have site visits.

• Submit your completed lab by the 10:00 the following Thursday

• The final lab will be due at the end of the last full week of classes.

End-Of-Term Work

• Take-Home Assessment

• At the end of the final full week of classes there will be an on-line assessment to be completed over the period of several days.  It will consist of questions drawn from the full term’s worth of work as well as short essay on the best or worst aspect of CAEE-201

About This Blog

We'll use this blog to post announcements and answer questions that are raised throughout this term related to CAEE-201.  We advise you to subscribe to it via an RSS reader such as Google Reader.  That way you won't have to go into BbLearn to see any changes.  There are many many blogs available on interesting topics.  A good place to search for others that may interest you is Technorati.