Microgravity and its effects

The effects of microgravity on the human body are quite nasty actually. Do not believe all those science fiction stories where people travel nilly-willy without a thought of bone loss and heart problems and brain changes and gastrointestinal problems. Gravity is far more important in the functionings of our bodies than you might at first think.

So my senior design team is trying to simulate gravity in our project by spinning our station. But then we had to figure out how much spinning the human body could take before getting sick. Try walking around with a slow spinning motion for a bit. You get dizzy after only a short time (I know because I tried).

Anyway, it is most interesting work and way more complicated than we initially thought.

Wind Tunnels and Ear Plugs

That has been my day thus far. The ear plugs came in when we ran the wind tunnel in my fluid dynamics lab at greater than 150 feet per second. It gets very loud with a high-pitchy sort of sound. But, hey! we're doing stuff with a real live wind tunnel so everything's okay.

And some time today I have to leave my comfy warm seat on my couch and drag my aching muscles (from exercising yesterday) out into the cold again so I can walk around and talk to recruiters at our spring career fair. Botheration, I probably have to wear high heels again, don't I...

Let's blow up the moon

Well...that's not actually the goal of my senior design class. But it is a possible outcome to some of our current ideas for launching a space module from the moon to Mars. It's been quite funny as we throw out the wackiest ideas and then realize what we just said and what the possible side effects would be.

Boundary Layers

I walked outside yesterday and felt the wind blowing around me and I thought to myself "There's a boundary layer around me!" It was so exciting.

You see, a boundary layer is that layer of air right up close to some object that has fluid flowing over it. Suppose you were like me and you went and stood outside with the wind rushing past you. Because of friction, the air exactly next to your skin is not moving, it has a velocity of zero. And then as you get farther from your skin, the friction is less and the air begins to move slowly and so on, increasing in speed until it has reached the same speed as the rest of the flowing air around you. The section of air from right up exactly near skin to the point where is has increased in speed to the rest of the air is called the boundary layer because it is a layer all around you of air changing velocities. Now the reason you don't feel this is because it is so extremely small. But it becomes important when working with things like submarines or airplanes because the boundary layer is larger and affects the performance of the object more.
But they can be fun to learn about.

Dimensional Analysis and the Buckingham pi Theorem!!!

The Buckingham pie Theorem is used to help Dimensional Analysis of pies by using coefficients and coefficient connoisseurs to analyze the dimensions of the circularity of the pie and the parameters thereof including and not limited to the radius, the circumference, and the angular velocity.

The following definition is premeditatively and with the deliberate design to confuse categorically and without exception wrong and misleading. Pay no attention to it.




Dear me, what fun it is to use a Thesaurus. And truly the Buckingham pi Theorem has nothing whatever to do with pies or the analysis thereof. It is really instead a method of finding things out about fluid flows without having to use dimensions which is especially nice for comparing things particularly when you have some model of some prototype. For example, suppose I want to build a gigantic jet engine and I know that the power it uses is dependent on some certain variables (like how fast the engine is pushing air out). Well, to actually build it and then run and test it and then modify it, etc... would take a long time and a lot of money. So I build a little tiny model instead. And so I have to change a number of things to get results that will also be true for the big gigantic engine. And I can compare everything by using dimensionless units in the very neat method outlined by the Buckingham pi Theorem.

How many living scientists do you know

who haven't died yet?

Prof. R who teaches my aeroelasticity and vibrations class is from Israel and speaks English with an accent. The accent isn't bad (though I could have sworn he was talking about a generalized mess instead of a generalized mass...it so confused me). But he has...interesting ways of expressing things.

Today, we heard a brief tangent lecture (that's a lecture on something not directly related to the topic at hand) about Dr. Theodore Theodorsen, a great aerodynamicist who doesn't get as much recognition as he should.

The best part was when Dr. Theodore Theodorsen was descibed as a living scientist of his time. And yes, he is dead now. But he was a living scientist when he was still alive. And now I'm wondering what he would have done if he had been a dead scientist of his time...



P.s. Theodore Theodorsen really is the guy's name.

A Random Tuesday

(not that anyone really cares to know how my Tuesdays go, but this was just fun, and I'm in a posting mood. Oooooh, I guess it time for a...Nothing Post!!!)

Had class. It is a boring(?) class. It is also an interesting class. It depends mostly on how much sleep I got the night before and whether I printed out the notes before class. Today it was good. Can anyone say Lagrange equations (mixed up with potential and kinetic energies)?

And then, I ate lunch. (This is getting so exciting. I don't believe all you nearly-non-existent readers can handle all this excitement.) There was yogurt in my lunch!
And fruit.

And then, my sister called me. (wow! if my day hadn't been made before at the yogurt, it certainly would have been at getting an actual real life phone-call!)
So I got dressed up. Except I think my sister's stockings got mixed with mine. So I had to wear light tan-ish colored pants with my black suit jacket instead of my nice matching skirt. And my sister came over all ready dressed up.

But then, we had to walk around and talk to people, trying to convince them they wanted to give us a job. But they weren't bitin'. Too bad. I got a stack of papers though, so I can harass them later with many submissions of my resume. Maybe that will change their minds.

Unfortunately, this all came to end much too soon and we had to leave to go to another class. This class was more exciting. Supposedly, anyways. It was so today because I actually did not fall asleep! Maybe it was because I was still in my suit clothes (It is incredibly undignified to fall asleep in suit clothes, you know). All sorts of equations that change whether you are dealing with ellipses, parabolas, or hyperbolas danced before my eyes and somehow made their ways to my notepaper.

Finally I was done! I could leave and go home and change out of my suit clothes! Except then, I thought I might stop by to pray for an hour at our Christian group's accustomed daily prayer hour in the afternoons. I met two others with similar intent and together we walked to our accustomed room.

But, oh horrors, it was being used. To take pictures of graduating seniors (most of whom only dressed up the top half of themselves so save the bother of dressing up their entirety). We were in dismay.

However, one brilliant (or not so brilliant) idea was proposed. Namely, we should walk around and pray for campus in the cold. We were all dreadfully excited about getting cold. So we went.

We walked a lot. Our campus covers a lot of ground. My feet got wet. I wasn't wearing boots, just dress shoes. But my feet did not get too cold, so it was okay. We also threw snowballs (an integral part of outside prayer in the winter). And one person ran up the side of a building and flipped off (he just wanted to show off his understanding and application of basic physics, I think).

At last I got back home. And changed my clothes, pronto (where does that word even come from, I wonder).

But dishes sat in the sink. So I washed them. And then my roommate made waffles. With blueberries (oh man, I think I'm gonna die for sheer delight).

My sister called again. But this time she called my roommate (she claims she called me first, but I don't believe her. I can always hear my phone vibrating, even when it is in the other room! Except, my received-call log seems to agree with her.) This time she wanted to sleep on the couch. So we let her. Just for tonight, you know.

And then, I sang three songs many times. I hope our choir director was finally satisfied. Three songs for two hours when one has to use the bathroom can be very...tiresome.

(This post is getting way too long. I'd turn it into a two-parter except you might not be able to stand the strain, and I'm nearly done anyways. Not that you care since you've probably stopped reading by now anyways.)

Then, I was surprised. There were two strangers sitting on my couch when I came home. One was my sister. The other was my roommate's sister. So we watched some tv together. And my roommate made popcorn with nearly all the kernels popped. It was amazing.

And now I am staying up much too late writing this nothing post. But this is the end now so I can go to bed.

Gravity!

Edit: I mistook which way things went as far as latitude vs. gravity goes, so I had to fix it.

This is absolutely exciting and amazing: we changed gravity yesterday!

Yes!!!!
Hurrah!!!

You probably all know that gravity changes with height, right? The farther you are away from the earth, the less you way?

Well that is not the only thing that affects gravity, or I should say the gravity constant of your perceived weight.

You all know that you weigh less the farther you go from the earth now(I just told you above, so you should know). But you don't actually lose anything from your body, right? No. That is because all the stuff of your body is actually the mass of your body, and that doesn't change.

Weight is the mass of your body times a gravity constant. And the gravity constant gets smaller the farther out from the earth you go. That's why you "weigh less".

But there is another thing that changes the gravity constant. And that is the rotation of the earth.

If you take a string and attach some object to it (which has a mass) and then swing the the string around and around, you can feel the object "pulling" on the string (there are physical laws explaining why it does so). We have sort of created a "weight" of the object.

You see, the earth is split up into a number of latitudes (the horizontal lines that go across a globe). And at each latitude, the ground beneath you is rotating at a different speed (too long to explain now, so sorry if you didn't know that before).
And we are attached to this earth through the friction that comes up through our feet.

So here we are spinning on this earth but the speed at which we are spinning changes depending on where on earth we are. And like that object on the string, our "created weight" changes with that rotation.

So the gravity constant isn't constant all over the earth even if there were absolutely no mountains or anything tall (the height piece of gravity).
Generalizing, we could say it is only at the standard at the North Pole and the decreases down to the equator.

If the earth spun faster we would eventually all fly off and that would solve our over-weightness problem in the United States, but probably not our over-massiveness problem.

And fly off into space!!!!!

Of Popcorn Kernels and Statistics

I'm taking Modeling and Analysis of Uncertainty this semester. It's a statistics course with lots of data and finding averages and standard deviations of things.

We have six small projects throughout the semester. The fourth one, which I have just completed, was highly amusing.

We were told to find a measurable characteristic of popped kernels of popcorn and get two brands of popcorn. Then we had to pop the popcorn and measure whatever it was we decided to measure. Extra points go to those who chose interesting measurable characteristics and measured them in unique ways.

My teammate and I sat in our student union Saturday night with our two bags of popcorn and realized we had very little on hand to measure anything. So we hunted through our backpacks and racked our brains for strange and unusual measurements. At last, we hit upon it: we would measure the saturatability of popcorn. Our reasoning was thus: if a popcorn kernel is highly saturable, then it should potentially be able to absorb more butter. And clearly more absorbed butter makes for tastier popcorn, and tastier popcorn makes a better brand. Therefore, the popcorn brand with the best saturability would be the better brand of the two.

Then we had to measure it. Fortunately, my teammate had a bright pink highlighter. We sat in the union marking popcorn for two and a half hours. We are pretty sure people gave us strange looks.

But all our popcorn was marked pink, and we finished our project.

Does your company have some BHAG?

That's right! I learned in class yesterday that a company needs:
Big Hairy Audacious Goals.

My fellow students and I could not determine what sort of goal counts as "hairy".

PD2 again

Crisis has been averted.
We are doing a nice happy project to encourage people to exercise more.

But the class itself took a turn for worse this past Wednesday.
We were required to watch this movie in class.
It was a quite horrible movie all about a bunch of guys doing sex and drugs on a Greek island.
Well, that wasn't the point of the movie...it was really about these group of soldiers who get stranded on this Greek island and discover that taking things easy and living the simple life is much better to their previous war-related activities and the constant fast-paced adventure they enjoyed. Several shocking scenes, however, caused me come to a different conclusion...

Anyway, now I have to write a paper about the leadership styles portrayed in the movie.

But watching movies only happens twice in the semester and I think the next one will be about some scientists, so I shall hope it will be much better.

PD2 = Moral Dilemma

Nobody ever told me PD2 would cause moral dilemmas!!!

Although it actually isn't a dilemma, just more of a tricky situation.

But fear not! I will not help start any Planned Parenthood groups at my school.


Now you are wondering what on earth PD2 is and what Planned Parenthood has to do with it?
Well, PD2 stands for Professional Development 2. We're required (all us engineers) to take classes that encourage professionalism and good business habits and leadership roles. The classes are split into three courses: PD1, PD2, and PD3. PD2 is mostly about leadership.
Because of this, we have a team project in which we are to do something that will have an influence in some community.
The two ideas my team has come up with thus far: encourage recycling on campus or starting a Planned Parenthood group.

I very quickly brought to the table that I was pro-life...and therefore not very likely to agree with the latter idea, although I was not opposed to raising awareness about health issues on campus.

When the idea was raised, I flew into a tailspin (an interesting maneuver with airplanes) and had to collect my thoughts so I could nicely but firmly state my disagreement. It is harder than you might think, 'cause you don't want to totally offend someone you'll be working with for the semester by shooting down their ideas (or actually, ever). But by God's grace the idea giver was receptive and understanding.

But the team is still deciding...

Errors

And now for another excursion into the fascinating world of math and errors.
First of all, you must realize the all important fact that nearly all solutions of math problems are approximations.
I know it seems hard to imagine (at least, I kept feeling there must be some way to get exact answers). But it is true. Your computer and your calculator and your hand calculations are usually riddled with errors: rounding errors, truncating errors, data errors, computational errors, forward errors, and backward errors (and maybe a few more that I have forgotten).

This post will explore backward and forward errors.

Have you heard of functions?

No?
Well, imagine a machine...like an oven. You put in a lumpy sticky mixture of ground-up grains, crushed olives, fermenting fungi, sodium chloride, sugars, and flammable elements combined so they are no longer flammable (i.e. H2O or "water" as it is commonly know as). You put this unlikely combination into the oven machine.
And in ~35min. a fragrant loaf of bread comes forth.

The oven did stuff to the mixture you threw in (well, not literally) and gave an output. We could call the oven a "function" (since it performs a function...baking bread) and the dough (that disgusting mess described earlier) as the input. The nicely baked bread is the output.

We could go even further. We could give the input a generic name "x" which can now stand for anything (not just bread dough, but cookie dough, brownie batter, chickens, cats, plants, 4, 7, 109, or anything else you like). And the output gets its own generic name "y". And the function even gets its own name too! It will be called f(x) (because it performs some function on x).

Now that we've got all that straight we can begin to talk about forward error.

Usually, or at least in an ideal world, you put an x in to your f(x) and get a particular y special to the particular x you put in. And this is the exact output that you would get.

But sometimes, you only get an approximation to your actual y. It's like putting in your bread dough and getting bread that was still doughy in the middle. It's only an approximation of the actual bread you wanted. Now suppose your actual bread and your doughy bread were numbers, than you could find the difference between the two of them. And that would be your forward error.

Like this:
y - approximate y = forward error


Now backward error is a little more tricky to explain. Suppose, you wanted the bread that was doughy in the middle...now it wouldn't actually be bread you were wanting. But we could suppose there is some other...thing that you might wish to make that actually produces doughy bread. Then the doughy bread would be the exact output and not the approximate output.

So then the input changes slightly.
And you get something like this:
x - approximate x = backward error
(the approximate x is the input that gives us the exact output of doughy bread)

Perhaps a visual would help?

















(click on image for clearer view)

Introducing...

Oh hurrah!
I am in rhapsodies right now!
Something absolutely delightful exists and now I know about it.


I am a fickle woman truly.
Last semester is was h.
Several semesters before that is was Re.
NOW it is...



del.

Oh del is so neat! It looks like an upside delta triangle.
And it is both a vector and a derivative operator at the same time!
And you can do super cool things with it like cross products and dot products and it takes the derivative of the other vectors at the same time!



Okay. You may all go back to your normal lives and not worry about del at all. But I shall go and enjoy the thrills I get every time I think that such a thing exists.

Late

I perceive that I have not lived up to my expectations exactly.
To be honest, I completely forgot I had ever planned on writing after coming back from class.
But I have been a little confused and tired this past week because of an ear/sinus infection I caught the week before classes and because of all the antibiotics I've had to take since then.
To be sure, by Thursday I was in a much more coherent condition, but I'm not sure even yet how much I have totally recovered.

So the important thing I wanted to mention about my critical thinking class is as follows:
My professor has said that one of the key things a critical thinker must do is abstain from making a decision when there is not enough information.
A critical thinker considers claims and beliefs and uses arguments to come closer to the truth. Sometimes, one simply does not know, and therefore, they need to be able to admit that. Most of us, however, dislike doing this. For one thing, we hate uncertainty, so there is a temptation to just choose an opinion or belief even if one does not have enough to decide on. For another thing, our social status demands us to know things. If we appear unsure or unable to decide, we are thought to be incompetent. Those who seem to know what they are talking about, very frequently are respected as knowing what they are talking about. So admitting that one does not know whether something is true or not can be harder than you might think.

I find this idea most interesting. It is like I went to class and had the professor tell me I needed humility. That is not heard in classes all the time. It is a different experience.

So, may you all learn humility this week, or at least, come a little closer to true humility before God.

Critical Thinking

This is an important thing to cover no matter what you are studying.
My class, which is studying this, starts in about 25 minutes.
So I do not, I am sorry to say, have the available time to write anymore about this topic.
At least, not at the present moment.

But I hope to do so in the near future.
Meaning in about 2 hrs. plus the 25 min.

To tide you over, you may all contemplate this:

X= Xo + Vo t + 1/2 a t^2

which is the formula for finding the position of a particle in motion, assuming a (acceleration) is constant. I am sorry it is such bad form. I hope to put it is better form soon.

Design

My first real design class started today. Our mini project, due in four weeks, must make dorm life more comfortable, safe, or fun. This is a slightly more challenging task to myself, seeing as how I never actually lived in a dorm. But perhaps I can cull ideas from my roommates at my apartment. Or perhaps I will even think of something useful for my own small room.

Either way, it should be an exciting class.





And for those of you wondering, those are celery pancakes, a "design project" I helped to make last semester for a party.

Equations again

Apparently some people find my excitement about equations to be amusing.
I really do not know what is so amusing about liking equations. If there were no equations or no people who enjoyed them, where would we all be?
We would be lacking large bridges, cars, trucks, airplanes, computers, dishwashers, economics, space shuttles, cell phones, cannons, cleaning chemicals, vacuum cleaners, diving boards, and many other things. You could even say food recipes were a sort of equation, so we wouldn't even have those.
Now do you see what excellent and amazing things equations are?

Of course, some equations look horrid and are horrid to solve, but others are absolutely beautiful and simple. Those are the most fun and sometimes even the most important. And those are the sort I like to share with everybody.

Equations!

I have more equations for all the people who (don't) read this!
I love equations, especially if I can use them.

So, there are three equations for three cases of finding solutions for differential equations. This is not going to be an explanation of differential equations and how to find their solutions, so just ignore that if you don't know what they are. The important thing is that I have three new equations that I like and that I have memorized because I have been doing so many problems with them and I would like to share them with everyone.

The three equations are as follows:

I am sorry they are so small. If you click on the picture, you can see them better. I have to figure out how to get alphas and betas in a blogger post still. Anyway, the first equation is for case 1 where you find the roots of a quadratic equation and the roots turn out to be nice ordinary ones (this is just more mathematical jumble, so if you don't understand it, don't worry about it). The second equation is for case 2 where the roots turn out to be one repeated root. The third equation is for complex roots. Those are the roots that get imaginary numbers in them.
And I think these equations are so fun. They save a lot of work.

Suppy and Demand

This is a picture of supply and demand curves. Supply and demand are two terms talked about in economics a great deal.

"Demand" refers to how much of a product do people want to buy. As you can see, the horizontal axis (the line with "quantity" under it) tells how much of some product people want to buy. The vertical axis (the line with "price" above it) tells what the price of the product is.
If the price is very high, people buy less of the product, but if it is cheap, people buy lots of it.

"Supply" refers to how much of a product the people selling it want to make. When the price of some product is high, people selling want to sell as much as they can of it, so there is a lot of the product supplied. But if the price is cheap, people do not want to sell that product, so the there is less supply of the product.

On the graph, there is a place where the two curves meet. That is called equilibrium. It is the price of the product where the sellers want to sell the same amount of the product as the buyers want to buy. It is generally the best price for the product.