Transcript Laser-plasma interactions in Ti doped SiO2

Welcome to the first week of discussion!
 If you get here early, think about both problems!:

A “force polygon” is a closed shape (polygon) that we construct by adding force
vectors geometrically using head-to-tail addition.
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On the “Minimizing Forces” problem,
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
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Try and draw a force polygon involving F1, F2, F, and the resultant R (include
arrowheads on the vectors for now!).
Can you draw this polygon so that R is “minimized” (i.e. has the shortest length
possible)? Hint: exploit the fact that while we know the direction of F, the magnitude
(length) |F| is not specified. Adjust the length until you see a condition for |R| being of
minimum length.
Think about this:
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How is this polygon useful? Can we use it to find what we need?
This force polygon should be a quadrilateral (we have four vectors), but we do not know
any laws to compute lengths/angles in quadrilaterals…how could we generally proceed
to find what we need in this problem?
 On the second problem, we need the diameter, how is this related to
the separation distance r in the gravitation equation? What do we do
about the masses in this equation (not known)?
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Sirajuddin, David
Welcome to the first week of discussion!
 Hello!
 As we go through the class, please feel free to
interrupt me, or raise your hand with any
questions/comments
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Sirajuddin, David
Who am I?
 Name: David Sirajuddin
 BSE in Nuclear Engineering from Univ. of Michigan
 3rd year PhD Student in NEEP dept. at UW-Madison
 I study experimental plasma physics for nuclear fusion energy
 …Like in Iron Man, not Spiderman 2
[LHD]
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Sirajuddin, David
Who am I?
 Hometown: Portage, MI
 I have been a Statics TA for two years now, so (hopefully) I know
what I am talking about by now
HSX in Engineering Hall
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[LHD]
Sirajuddin, David
What we do in discussion
 Discussion is an interactive session!

Feel free to interject me anytime

I am not trying to fool anyone, if you do not understand something I am doing or
just do not agree with me, let me know ASAP. If I cannot answer your question on
the spot, I will get back to the class later about it.
 Typical discussion agenda:
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Attendance
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Review any sticking points on returned assignments
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Review any key slides from previous lectures
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Answer upcoming homework or any other questions about the material (~ 10 minutes)
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Work through one or two problems together (~ 40 minutes)
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Sirajuddin, David
Grades
 Who grades what?
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Connect HW: computer graded
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Design HW: TA graded
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Exams: one TA grades one exam problem for every student in the class
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All of us TAs have been working together now for at least a semester. We are all in
communication to establish grading consistency, i.e. there is no “easy” or extra “strict” TA in a
damaging way grade-wise (really). If some inconsistency is present, we will resolve it in the end.

Your final course grade will be assigned by Prof. Plesha approximate straight grading scale and
weights:
Approx. Grading
Weighting
A
90-100%
3 midterms (15% each)
45%
B
80-90%
Final quiz
25%
C
70-80%
Connect HW
10%
D
60-70%
2 design reports (5% each)
10%
F
< 60%
Discussion participation
10%
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Sirajuddin, David
Grading Policies
 Design (DSN) Homework

2 projects combined = 10% of total grade (5% each)
We will talk about how these are graded later on in the semester, I will try to get a rubric
uploaded for all students to see ASAP
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For future reference:
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Sample rubrics from Fall 2010:
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DSN1: http://www.itcanbeshown.com/For_Students/EMA_201_DSN1_Fall_2010_Grading_sheet.pdf
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DSN2: http://www.itcanbeshown.com/For_Students/EMA_201_DSN2_Fall_2010_Grading_Rubric.pdf
Technical writing overview
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
http://www.itcanbeshown.com/For_Students/Technical_Writing_Tips.ppt
Sample Design Report
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Problem Statement: http://www.itcanbeshown.com/For_Students/dsn1overheadcamera.pdf
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Report: http://www.itcanbeshown.com/For_Students/Design_of_Cabling_for_an_Overhead_Camera.pdf
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Sirajuddin, David
Grading Policies
 Exams
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3 Midterms + Final exam = 70% of final grade
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Different TAs grade your exams
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For grading consistency, one TA grades one question for every student in the class
 You will be subject to different grading biases and methods
 For cosmetic issues, you should be fine if you follow the advice in this presentation (units, axes, etc.)
 Note: it is to your benefit to be as clear as possible, if your work is not followable a TA may be forced
to deduct a significant portion of the points due to not knowing what it is you were doing.

After you receive your graded exams back, solutions will be posted for your review. You should check to
make sure the TAs graded your work accurately.

If you disagree with the way something was handled on a particular question grade-wise, you will have
an opportunity to submit your exam to Dr. Plesha for a regrade. Please only do this if you have a reason,
and know the reason. Thinking you just “deserve more points” does not make any sense to anyone.
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Sirajuddin, David
Grading Policies
 Exam problem solution deductions (not necessarily how other Tas
grade)
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Routine Deductions
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Units must be used every time you write down a number (this defines what that number is), two
levels of deductions:
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Larger deduction: Noticeable negligence of units (including when units are only in the final answer)
Smaller deduction: When units are present, but the use is inconsistent
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Coordinate Axis
 Deduction if a needed coordinate axis is missing (i.e. when not in the problem statement itself)
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Free Body Diagrams (FBDs)
 A variable amount of points are deducted based on how many needed FBDs are missing.
 An FBD is not a drawing of the scenario, you need to draw the forces too.
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Forgetting “= 0” (see below)
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This is a statics course, so obviously almost equation you write down “= 0” but you have to write it.
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Note how I labeled the equations below (“sum forces in the x-direction”), please do not just write down
random equations.
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I will only mark points off if a gross neglect is shown
F
x
 0 :12lb  FR  0
 F :12lb  F
x
R
 F :12lb  F  0
 F  0 :12lb  F
N.B. All these deductions are per problem
x
R
x
R
Grading Policies

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Sirajuddin, David
How to get help

Walk-in Help –
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Fourth floor, near the vending machines. We are located in the area designated with an overhead
(red) sign that reads “Engineering drop-in tutoring.”
Feel free to get help from any TA
7:45
8:50
9:55
11:00
12:05
1:20
2:25
3:30
4:30
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Monday
Tuesday
Wednesday
Thursday
Friday
Adrian
Harsha
Adrian
Harsha
Miguel
Rob
Miguel
Rob
Adrian
Ed
David
Ed
David
Rob
Adrian
Harsha
David
Harsha
Lecture
Lecture
Lecture
Lecture
David
Miguel
David
Ed
Rob
lecture
lecture
Miguel
Ed
Sirajuddin, David
How to get help

Prof. Plesha office hours – MWF 10:30am – 11:30pm

ΠΤΣ Mechanical Engineering Honor Society Tutoring (Wendt Library, 4th floor):
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Sunday to Thursday at 7pm – 9pm

HKN and Engineering Student Services

My “office hours” = walk-in help, but you are welcome to come to my office anytime to
see if I am around (2336D Engineering Hall,
http://www.itcanbeshown.com/For_Students/map.PNG)

Email me any questions: [email protected], or I can meet you outside of class for
additional help (i.e. by appointment)

Discussion website: http://www.itcanbeshown.com
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Sirajuddin, David
How to get help from me
 David Sirajuddin
 Office: 2336D Engineering Hall (right down the hall)
 Email: [email protected], [email protected]
 My WIH hours:
 M: 4:30pm – 5:30pm
 W: 12:05pm – 1pm, 4:30pm – 5:30pm
 R: 11am – 12n
 F: 12n – 1pm
*R means Thursday
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Sirajuddin, David
Discussion Website
 http://www.itcanbeshown.com (under the “For Students” section)
 Much of what we do (and more) in recitation is on this site
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Problems and solutions (more than we cover in section)
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Exam review sheets
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Slideshow presentations (like this one)
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The actual grading rubrics we will use to grade design projects
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A sample design report
 If you forget the URL, refer to any one of my emails, it is in my signature
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Sirajuddin, David
Questions?
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Sirajuddin, David
Sorry, no icebreakers
 For Design projects, you *may* be allowed to work with other
students
 At some point, you may find yourself needing some assistance.
 Your peers are an excellent source for collaborative
conversations/work (just make sure you still learn)
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Sirajuddin, David