MrsDrPoe: I Promise I'm Leaving This Time...

Many days have come and gone, and once again Foto Friday has arrived.  Last week, I posted about my home away from home, Starkville, Mississippi...this week I'll share some more pictures from my trip because I'm still here (oh the joys of research).

My simulations and I have had a love-hate relationship this week, as in they've loved to hate me:

Every time I thought some progress has been made, the results look terrible- I've planned to leave town every day this week (literally).  But thankfully I've had good company despite my difficulties.  My good friend Ms. K. Davis was kind enough to come to the HPC2 so I wouldn't be working alone at night:

One day I saw this car on campus, and it reminded me of Mr. Poe:

I wanted to run home immediately, but I couldn't.  One day soon I'll make it back to my home, my husband, and my dogs...but until then, you can just call me...Brett Favre.

MrsDrPoe: The Second Law of Thermodynamics as It Applies to Christianity

This Theology Thursday, I invite you to open up your Bibles with me as we take a look at a portion of God's word.  Today we'll be taking a bit of a different approach to some passages, examining how the second law of thermodynamics applies to Christianity.

The second law essentially states that the total amount of entropy in the universe is always increasing or every existing process is irreversible.  This wording may not mean much to you if you're not in some type of science or engineering field, but it definitely effects you.  This law in layman's terms tells us that no process is 100% efficient i.e. you put in more energy than you get out in useful energy or work.  

For instance: A tank of gasoline has x amount of chemical energy.  Engines use the gas to power your vehicle, but they only 'see' y amount of the energy available- the rest (x-y = z) is 'lost' to friction, heat dissipation, etc.  The fact that there is a lot of chemical energy that does not go directly into running your car means that the process is much less than 100% efficient.  

While we know that energy can never be created or destroyed (the first law), we should now also know that not all of the energy we put into something produces useful results.  They key in much of engineering is to design processes which eliminate as much of this 'wasted energy' as we can, ensuring that these processes use energy as efficiently as possible.


So what in the WORLD does this have to do with Christianity?  Look at these verses from the new testament:

"And do not be drunk with wine, in which is dissipation; but be filled with the Spirit" (Eph 5:18)

"For we have spent enough of our past lifetime in doing the will of the Gentiles- when we walked in lewdness, lusts, drunkenness, revelries, drinking parties, and abominable idolatries.  In regard to these, they think it strange that you do not run with them in the same flood of dissipation, speaking evil of you." (1 Pet 4:3-4)

The word dissipation in these verses is actually the Greek word asotia, which means prodigality.  In Luke 15, we read of Jesus' parable of the prodigal son, so most of us are probably familiar with the word 'prodigal'...but do we truly know what it means?  Prodigal is defined most frequently as 'excessive wastefulness.'  Thus in the above passages, these sinful acts are called wasteful, which means that in committing them we are being tremendously inefficient with the energy given to us by God.

But if we say to ourselves, "well this doesn't apply to me, because I don't do any of these things," we need to realize that "...all have sinned and fall short of the glory of God..." (Rom 3:23).  Like the car engine, much of the energy and things we have are wasted in that they do not serve a useful purpose to the Lord by glorifying His name.  While we can never be perfect as Christ was, His model of life on this earth should be what we're striving to match every day- we should all be 'engineers' trying through the grace of God to make our lives as 'efficient' as possible by ridding them of sin.

MrsDrPoe: Mrs. Holley's Cabbage Salad

It's What's for Dinner Wednesday tonight on the blog!  In honor of the Holleys, I'd like to share with you an easy, tasty salad introduced to us by Mrs. Holley.

Ingredients: cabbage, olive oil, lemon juice, salt and pepper (not pictured).

Slice the cabbage thinly using a knife or food processor (about 1/5 of the cabbage*).  Put the cabbage in a bowl, pour on olive oil (about 1 tablespoon*), lemon juice (about 1 1/2 tablespoons*), and salt and pepper to taste, and toss to coat:

We particularly enjoy eating it alongside my special green beans and chicken casserole:

What are you having for dinner tonight?


*for two people

MrsDrPoe: The Holleys

If you're a frequent reader, you may recall the name "Holley" used quite often in my Theology Thursday posts.  This week's Poe's Pals will reveal for you the face that goes along with the name.  Meet the Holleys:

Although we've only known these folks for over three years, it feels like we've known them our whole lives.  We first met Mr. T. and Mrs. Holley when they came back from Argentina to visit family; shortly after that, they decided to make Starkville their home.  It has been such a blessing to get to know this wonderful family during the time we were in school! 

Mr. T. Holley is the preacher here and one of the most knowledgeable and dedicated Bible students I know.  Mr. Poe and I have learned so much from him- both directly about the Bible and about good Bible study habits.  Mrs. Holley is his fantastic counterpart.  She is so friendly and hospitable to everyone she comes across, welcoming them into her home and cooking them wonderfully delicious food.  Mr. S. Holley is a great, puzzle-loving friend to us as well- he helped us move, sledded with us on our birthdays, and has given us his bed on more than one occasion.  Ms. Holley is also one of our firends who always loves having us over for visits- when we leave, she sees us to the door with a big "thank you for coming!"

We look forwarding to visiting the Holleys every time we come to Starkville, and I suggest that you stop by when you're in the area too!

MrsDrPoe: Potential Flow, Part III

Once again Thesis Tuesday is upon us!  Today we'll be concluding our investigation into Potential Flow by examining combinations of the flows we've looked at so far in both Cartesian and cylindrical coordinates.  This is possible because potential flows obey the superposition principle.

Doublet

A doublet is the combination of a source and a sink of equal strenghts (+/- m) located 2a apart, as we can see in the figure below:

To find the potential function and streamfunction for the doublet (in relation to point P), we simply add the two potential functions and the two stream functions respectively:

PHI = PHIsource + PHIsink = 0.5*(m/pi)*ln(r1) - 0.5*(m/pi)*ln(r2)

PHI = 0.5*(m/pi)*ln(r1/r2)

PSI = PSIsource + PSIsink = 0.5*(m/pi)*theta1 - 0.5*(m/pi)*theta2

PSI = 0.5*(m/pi)*(theta1 - theta2)

If we allow the distance between the source and sink shrink (a goes to 0, theta1 goes to theta 2, r1 goes to r2), we arrive at:

PHI = ((m*a)/(pi*r))*cos(theta)

PSI = -((m*a)/(pi*r))*sin(theta)

Flow Over a Cylinder


To examine flow over a cylinder, we will combine a doublet and uniform flow.  Before we can combine these flows, however, we must first translate uniform flow into cylindrical coordinates (remember- you can never mix coordinate systems) using:

x = r*cos(theta), y = r*sin(theta)

Next we simply combine the potential function and streamfunction from each flow to find these functions for the combination:

PHI = PHIdoublet + PHIuniform = ((m*a)/(pi*r))*cos(theta) - U*r*cos(theta)

PSI = PSIdoublet + PSIuniform = -((m*a)/(pi*r))*sin(theta) + U*r*sin(theta)

If we let (m*a)/pi = U*R*R where R is the radius of a cylinder we're interested in:

PHI = -U*cos(theta)*(r - (R*R)/r)

PSI = U*sin(theta)*(r - (R*R)/r)

Note the streamline where PSI = 0, r = R is taken as the surface of a cylinder of radius R.  We can do this because streamlines run parallel to the flow, meaning no flow crosses the streamline, just like no fluid can cross a solid (non-permeable) boundary; therefore, any streamline in an invisicd flow field can be considered a solid boundary.  All streamlines for PSI > 0 give the inviscid flowfield over the cylinder.  

Streamlines exist inside the cylinder (from the doublet) as seen below, but we neglect these.  We can also determine the stagnation point for the flow by finding the velocity from the potential function and streamfunction and noting where it equals zero.  By combining other potential flows in a similar manner, we can examine inviscid flow around other objects.

And that's potential flow.  Tune in next week when we'll look into the third major governing equation of fluid mechanics - the energy equation.

MrsDrPoe: Being a Responsible Receiver

It's another Money Monday here at the blog and the final installment of "Giving Gifts without Going Broke."  So far in this series we've talked about some gift-giving basics, as well as cost-effective purchased and homemade gift ideas.  Today, we'll be examining the other side of the coin- how we can be responsible receivers. 

While we may not be in a position that requires us to find most cost-effective ways to give, we must be consious of the fact that others may be.  There are two major aspects to being a "responsible receiver":

Being PROACTIVE

The proactive receiver realizes ahead of gift-giving-time the financial situation of those on his/her list.  To help the giver avoid the awkward conversation of, "I can't afford to buy you x, y, or z this year," the receiver develops a gift list for the giver that falls well within his/her budget limitations, noting possible cost-effective solutions, such as specifying whether or not a used product is acceptable.  If the giver is particularly strapped for cash, a proactive receiver also may suggest having a homemade holiday or "alternative" gift ideas.

For instance: 

"I really want some of the Manheim Steamroller Christmas CDs...I usually find used - good condition ones on Amazon for a decent price."

"I would love a night out with Mr. Poe...the best gift ever would be a few nights of free dog-sitting."

Being RETROACTIVE 

The retroactive receiver may not realize a financial situation until after gifts have been exchanged.  He/she gratefully accepts whatever token is presented, keeping in mind that it's the thought that counts and, as Paul told the elders from Ephesus in Acts 20:35, "I have shown you in every way, by laboring like this, that you must support the weak.  And remember the words of the Lord Jesus, that He said, 'It is more blessed to give than to receive.'"

For instance:

Gifts often given to parents by their small children (like small porcelain figurines from the dollar tree) are accepted readily and thankfully...we should simulate this behavior.

While we're discussing that this attitude is important for the recipient of an obvious "giving without going broke" gift, the role of the retroactive receiver is surely not limited to this group of individuals.  We should all be thankful for everything we have been given, realizing that love and service to/from those around us (and to/from God) are so much more important than stuff.