MrsDrPoe: How to Change a Flat

The inspiration of this Foto Friday post* came from a lone trip a few weeks ago. I found my mind wandering to several things that could go wrong on the road, which lead to the possibility of a flat tire...without Mr. Poe or any friends in the area to aid me. As I mentally went through the steps in the process of changing a flat, I thought that this subject would definitely make a helpful post for myself, and I hope that you agree!

Step 1: Pull over.

If you get a flat, your car will try to veer to the side that the flat is on. When this happens, stay calm, firmly grasp the wheel, turn on your hazard lights, and carefully make your way to the shoulder. Don't freak out if you can't immediately pull over- a ruined wheel is a lot easier to replace than a life. If you're on a one-way stretch of road like the interstate, try to pull off on the shoulder that allows you to have your vehicle as a barrier between you and traffic as you work (ex: flat is on the left side, pull off on the left shoulder). Be sure to pull off the road as far as you can while keeping the car on relatively flat ground.

Step 2: Take precautions.

When you're safely pulled over, turn on your hazard lights if you've forgotten; turn off the car; and put on the parking break to help stabilize the vehicle during the tire changing process. Text or call a friend to let someone know where you are and when you stopped- be sure to tell them to check on you if you don't touch base again in 30 minutes.

Step 3: Get out your gear.

Your spare tire/doughnut, lug wrench, and jack will be in different locations depending on what type of vehicle you have. For our car, all the stuff is in the trunk underneath a section of carpet:


Make sure you've located the necessary equipment before the time comes that you actually need it. You'll also want to periodically check your spare/doughnut to ensure that the tire is at its proper pressure (this pressure can be found in your car manual or on the tire).

Step 4: Remove the hubcap.

Most newer vehicles have a lovely cover over the center of the actual wheel; this must be removed before you can get to the lug nuts. The decorative covers over the lugs will probably be plastic, so be careful with them (you may not need the wrench at this point). After these covers are loosened (A), remove the cap (B), exposing the lugs (C):


Next, you'll want to use the lug wrench to loosen the lug nuts at this point (it's ok to kick or stand on the wrench...see A in the figure in Step 6); if you don't loosen the lugs before you raise the car, you'll literally just be spinning your wheels when you try with the tire in the air.

Step 5: Set up the jack.

There should be a long, thin metal piece on the underside of your vehicle (like Mr. Poe is pointing to in A). This piece should fit in the groove of your jack (B). To ensure that this happens, set the jack up and start raising it; when the top of the jack nears the underside of the car, line up the groove with the metal strip (C):


Continue to raise the jack (and the car at this point) until the wheel is entirely off the ground and can spin freely.

Step 6: Remove the tire.

Hopefully you loosened your lugs (A) in Step 4 (if not, lower the car, loosen them, and then repeat Step 5). Once all the lug nuts are removed (B), place the lugs in the hubcap (C) or some other place where you don't loose them:


Carefully grasp the tire with both hands and remove it from the vehicle, pulling out and then down to the ground. As an additional safety precaution, you can lay this tire with its tread perpendicular to the ground under the car beside the jack. That way, if something crazy should happen and the jack fails, the car will land on the tire and not your foot.

Step 7: Put on the spare.

There are two sides to a doughnut (if that's what you have). One side (A) has an extruded flat piece in the center of the wheel; the other side has a concave flat piece (B). The extruded flat piece is the back of the wheel; this side should face the car when you're putting the doughnut on:


If you have little to no upper body strength (like me), you can set the spare on your foot/feet and use it/them to help you lift the new wheel (A). You'll want to first line up the top hole in the spare wheel with the top screw; prop the wheel on this screw and then rotate it until the other screws and holes line up (B). Place the lugs back on with your fingers in a star pattern (bottom left, top, bottom right, top left, top right) (C); then use the lug wrench to tighten each lug nut down as much as possible (until the tire spins...again using the star pattern). You'll need to go over the first ones that you tighten a second time (D):


Step 8: Finish up.

Remove the old tire from under the car and slowly lower the car to the ground. Using the wrench, tighten the lug nuts one final time, ensuring they're as tight as you possibly can get them:


Pack your equipment back into your car and wipe up if you have some napkins (unless you have gloves, you're going to get a little dirty). Call or text your friend to give him/her an update; turn on the car; take off the parking break; and carefully merge back into traffic. Once you're up to speed, turn off your hazard lights.


So that's it! I hope this has been as useful for you as it has been for me, and until next time...happy motoring!

*A special thanks to Mr. Poe for some additional safety tips, reviewing this post, and being my photographer and an all-around great husband.

MrsDrPoe: The Key to Singing

Once again Theology Thursday is upon us, and as always, I invite you to open your Bibles with me as we examine a portion of God's word. Today we will take a brief look at one aspect of our worship to the Lord- singing.

In several places in the new testament, we are instructed to sing to the Lord:

James 5:13 - Is anyone among you suffering? Let him pray. Is anyone cheerful? Let him sing psalms.

Eph 5:18-21 - And do not be drunk with wine, in which is dissipation; but be filled with the Spirit, speaking to one another in psalms and hymns and spiritual songs, singing and making melody in your heart to the Lord, giving thanks always for all things to God the Father in the name of our Lord Jesus Christ, submitting to one another in the fear of God.

Col 3:16 - Let the word of Christ dwell in you richly in all wisdom, teaching and admonishing one another in psalms and hymns and spiritual songs, singing with grace in your hearts to the Lord.

1 Cor 14:26 - How is it then, brethren? Whenever you come together, each of you has a psalm, has a teaching, has a tongue, has a revelation, has an interpretation. Let all things be done for edification.

1 Cor 14:15 - ...I will sing with the spirit, and I will also sing with the understanding.

Based on these verses, it seems pretty obvious that we should sing to the Lord. We can also see some of the purposes of our singing- it shows we're cheerful; it shows we're filled with the Spirit; it can teach, admonish, and edify us and our fellow brethren. These verses also show us one important instruction that we must keep in mind when singing to the Lord: we should sing with understanding.

This instruction should make sense to us in the context of teaching, admonishing, and edifying one another and of glorifying God in song. If you were teaching a child to add fractions, would you expect him/her to get anything from your lesson if you didn't know what you were talking about? If I told you, "If you need anything, call me. I'll be praying for you." in Italian, would that be of any comfort to you? If you wanted to get your mother a card for Mother's Day, wouldn't you try to understand what a card was saying to make sure that it conveyed to her the exact sentiments that you wanted to? In these everyday examples, we can see that understanding is crucial to teaching, admonishing, edifying, comforting, glorifying, etc. Italian may sound pretty, but if you don't know what I'm saying it means nothing- just like singing "ye that labor and are heavy laden, lean upon your dear Lord's breast*" is not a comfort unless it is sung (and heard) with understanding. We must take great care to focus on the words of the songs that we sing while we are singing them.


Mr. Poe and I were in a Bible study of sorts several weeks ago, when he brought up his favorite hymn, "It Is Well with My Soul." The song is a beautiful one, due to both the musical notes and the fantastic lyrics. Let's look at a couple of verses as another example:

"My sin, oh, the bliss of this glorious thought! My sin, not in part but the whole, Is nailed to the cross, and I bear it no more, Praise the Lord, praise the Lord, O my soul!"

How encouraging and comforting! Every time we sing this verse, we are reminding ourselves and those around us that Jesus Christ died on the cross in order to redeem us! "He poured out His soul unto death, and He was numbered with the transgressors, and He bore the sin of many and made intercession for the transgressors." (Isaiah 53:12) We are no longer slaves to sin because Christ bore ALL our sins on the cross for us!

"And Lord, haste the day when my faith shall be sight, The clouds be rolled back as a scroll; The trump shall resound, and the Lord shall descend, Even so, it is well with my soul."

How we Christians do long for this day! Christ's glorious second coming... But think about this: suppose you've never become a Christian or suppose you are a Christian who's returned to living in sin AND you're singing along with this 'beautiful song.' By singing these lyrics, you are asking God to "haste the day" of His return...you're asking for your own condemnation to come quickly!

Do you see why we need to sing with understanding?

On a related note, if any of you will be in the Atlanta area during the next several weeks, one of our adult classes will be focused on this topic to help us better praise God in song.

*From "Hark! The Gentle Voice"

MrsDrPoe: Tuna Salad

It's another What's for Dinner Wednesday on the blog. Tonight I'd like to share with you a meal that's quick, easy, and great for lunch or dinner any day of the week (unless you're pregnant): Tuna Salad. I typically serve this on bread or buns, but it is equally tasty on your favorite cracker.

Ingredients (per serving): 1 5-6 oz can of tuna in water (drained), 1 tablespoon lite mayo, 2 tablespoons dill pickle relish:


Combine ingredients in an appropriately sized bowl with a fork. Serve immediately or refrigerate for up to one week:



There are a multitude of alternate methods for making tuna salad. Two examples are: using sweet relish instead of dill or adding an additional 1-2 tablespoons finely chopped apple to the mix (Mrs. Holland's favorite).

How do you typically make your tuna?

MrsDrPoe: Ms. Nowell

For the latest edition of Poes' Pals, I present to you Ms. Nowell:


Ms. Nowell is another friend from Mississippi that Mr. Poe and I have known for several years; we first met her shortly after she moved from the great state of Texas. She is a joy to be around, and we greatly admire her desire to serve the Lord and her drive to work hard at any task she begins.

Often Ms. Nowell invites her classmates to Bible studies and shows hospitality by gathering fellow students to the home she shares with her grandfather- I remember many an enjoyable evening of Rock Band and karaoke there. She has also had to make some difficult choices in order to better align her life with the patterns found in Biblical examples and teaching, which is a great encouragement to all who are around her. Currently, Ms. Nowell is participating in a nursing program in which she is doing quite well. When she finishes, I know she will be such a blessing to the babies and families she'll work with wherever she chooses to get a job!

If I've said it before, I've said it a million times, Mr. Poe and I miss Ms. Nowell and all of our Starkville family very much!

Special thanks to Ms. K. Davis for use of her fabulous photography skills.

MrsDrPoe: Conservation of Momentum, Part V

It's Thesis Tuesday on the blog, and today we'll be continuing our examination of the Conservation of Momentum equation, this time focusing on the inviscid reduction of its differential form.

If you recall, the difficulty with the differential momentum equation is that we need to define the stress terms. Previously, we obtained the following results:

d/dx(Sxx) + d/dy(Txy) + d/dz(Txz) = -d/dx(p) + mu*(d/dx(d/dx(u))+d/dy(d/dy(u)) + d/dz(d/dz(u)))

d/dx(Tyx) + d/dy(Syy) + d/dz(Tyz) = -d/dy(p) + mu*(d/dx(d/dx(v))+d/dy(d/dy(v)) + d/dz(d/dz(v)))

d/dx(Tzx) + d/dy(Tzy) + d/dz(Szz) = -d/dz(p) + mu*(d/dx(d/dx(w))+d/dy(d/dy(w)) + d/dz(d/dz(w)))

If we examine the case of inviscid flow, this means we are looking at an area where viscous effects are negligible (mu = 0). Generally this occurs in the far-field, i.e. in a region of the fluid far away from any walls or boundaries. This leaves us with:

d/dx(Sxx) + d/dy(Txy) + d/dz(Txz) = -d/dx(p)

d/dx(Tyx) + d/dy(Syy) + d/dz(Tyz) = -d/dy(p)

d/dx(Tzx) + d/dy(Tzy) + d/dz(Szz) = -d/dz(p)

So our stress tensor terms are ONLY related to changes in pressure. If we replace these new equalities in the differential form of the equation, we end up with a set of equations known as Euler's Equations. It is important to note, however, that this set is only valid for inviscid flows.

If we apply the assumptions of steady, incompressible flow with no outside forces acting on the fluid to Euler's Equations, we get:

u*d/dx(u) + v*d/dy(u) + w*d/dz(u) = gx - (1/rho)*d/dx(p)


u*d/dx(v) + v*d/dy(v) + w*d/dz(v) = gy - (1/rho)*d/dy(p)


u*d/dx(w) + v*d/dy(w) + w*d/dz(w) = gz - (1/rho)*d/dz(p)

Using a vector identity (which we won't discuss in further detail), and applying along a streamline (lines always parallel or tangent to the flow), we can further reduce this equation to:

0.5*V*V + (p/rho) + g*y = constant (along a streamline)

or: 0.5*V1*V1 + (p1/rho) + g*y1 = 0.5*V2*V2 + (p2/rho) + g*y2

This is Bernoulli's Equation, and it is written for two specific points along a streamline.

Restrictions:

Remember that this equation is only applicable to flows of fluids where the assumptions we made to derive the equation (steady, incompressible, inviscid, along a streamline, no outside forces) hold. It is CRUCIAL to realize that if the flow does not meet these qualifications, this simplified equation CANNOT be used!

If our flow cannot be treated as incompressible, but the other assumptions hold, we can modify the Bernoulli Equation so that it can still be used. For compressible gases, we can apply the ideal gas law to obtain:

0.5*V*V + y*g + R*T*ln(p) = constant (along a streamline)

For unsteady flows, we can modify the equation by the addition of a single term integrating the acceleration over a streamline:

0.5*rho*V1*V1 + p1 + rho*g*y1 = rho*int(d/dt(V))ds + 0.5*rho*V2*V2 + p2 + rho*g*y2

Physical Meaning:

The Bernoulli Equation is simply the mathematical statement of the principle "the work done on a particle by all forces acting on the particle is equal to the change of the kinetic energy of the particle." We can better see that if we look at each of the terms in the equation. As the particle moves, we see forces of pressure and gravity acting on it (the z*g and p/rho terms). This is directly connected to the amount of kinetic energy that the particle has (0.5*V*V).

If we multiply each term in the Bernoulli Equation by the density, rho:

0.5*rho*V*V + p + g*rho*y = constant (along a streamline)

we obtain the pressure form of the equation. Here p represents the thermodynamic pressure of the fluid as it flows (this pressure determines the state of a fluid, i.e. whether it is a gas or a liquid). This value is typically termed the static pressure of the fluid, since it could be measured by moving along with the fluid or being static in relation to the fluid. The third term is the hydrostatic pressure, which is associated with the hydrostatic pressure condition. The second term is called the dynamic pressure since it is associated with the velocity of the fluid.

The combination of the first two terms in the equation is the stagnation pressure. This pressure represents the conversion of all the kinetic energy into a pressure rise, which occurs at a stagnation point where the velocity is equal to zero. The streamline leading to a stagnation point is called a stagnation streamline. The sum of all three terms in this form of the Bernoulli Equation is known as the total pressure, which is constant along a streamline.

Often in Mechanical Engineering, the Bernoulli Equation will be written in head form; this form of the equation is particularly useful for pipe flow and can be derived by dividing each term in the original equation by the gravitational constant, g:

(p/gamma) + (0.5*V*V/g) + y = constant (along a streamline)

In this form, the pressure term is called the pressure head, which represents the height of a column of fluid needed to produce the pressure p. The velocity term is called the velocity head, which represents the vertical distance needed for the fluid to fall freely to reach the velocity V from rest. The height term is the elevation head, and it represents the potential energy of the fluid.


Next week we'll look at some very simple examples of how to employ the Bernoulli Equation. Stay tuned!

MrsDrPoe: Deals Deals Everywhere! 8/28

It's the start of another week, and that means Money Monday has arrived! I'd like to share with you guys some great deals I've taken advantage of this week at CVS, Walgreens, Advanced Auto Parts, and PetSmart:

CVS


St. Joseph Asprin ($2/36 ct.) - $1/1 SS 8/07; $2 back in RR (you make $1!)
Pringles ($1.50/can) - $1/4 PG 7/31, 8/31
Charmin ($5.44/12 rolls) - $0.25/1 PG 7/31, 8/31
Dawn ($0.99/10.4 oz) - $0.50/1 PG 7/31, 8/31
Orbit ($1.37/pack) - $1/1 CVS coupon printing at price checker

I bought: 8 cans of Pringles, 3 packages of Charmin, 2 bottles of Dawn, 1 bottle of St. Joseph Asprin, 1 pack of Orbit for...

Total Regular Price: $52.46
Total Sale and Coupons: $21.46
ECBs Used: $5.00
Total OOP: $26.00
ECBs Back: $2.00, plus $10 gas card

Wags

Carmex Moist Lip Balm (Vanilla or Lime Twist, 0.15 oz)

Total Regular Price: $2.10
Total Sale and Coupons: $0.49
ECBs Used: $1.00
Total OOP: $0.61
ECBs Back: $1.50

Advanced Auto Parts

5 quarts (individual or jug) or Havoline oil + 1 Drive Works filter: $15.99
5 quarts (individual) Quaker State oil + 1 Purolator Classic filter: $15.49

We took advantage of both of these deals (there weren't any Drive Works filters to fit our car), paying $35.29 OOP and saving $20.94. They also had a deal on oil changing gear (pan, etc.) like Mr. Poe previously discussed if you're in need of it.

PetSmart


I bought Layla a 40 lb bag of Iams for...

Total Regular Price: $41.44
Total Sale and Coupons: $5
Total OOP: $36.44

A great deal, plus there's $55 in Iams and PetSmart coupons in the bag!

Stay tuned next Monday for more deals and a special surprise!