Let's Learn SCIENCE

So! I learned all about IP addresses and HTTP headers last night, for the sake of watching Miss Fisher’s Murder Mysteries over on ABC. I figured I could teach something, and provide a useful layman explanations on how data is sent over the internet. (As usual, if I get something wrong please tell me so I can correct it!)

So, want to watch Australian (or any other nation) tv? There are a number of possible options you can try. The first, and easiest, is to use a proxy website, where you simply paste the url of your streaming website into their server bar, and hit go. KProxy is one such example.

However, for streaming media, these websites are either too slow, or straight up block streaming capabilities. So they aren’t useful for this purpose. The next option would be use find a proxy IP address and connect to it through your web browser’s proxy options. This method is awesome! … If you can find an IP address that actually WORKS, that is. It can be a tedious, and rapidly aggravating process.

The last option doesn’t involve a proxy, and is also the method that I’ve found works for a large number of location-locked video streams.

This method involves altering your HTTP header fields, which are components of the header section of request and response messages. A list of them can be found here.

Okay, great, what does any of that mean? Well, scrolling down through the list, you’ll see a number of different options. The one we’re specifically looking for is X-Forward-For. Okay, cool, what does that mean? Well, that’s the field that lists what IP address you’re actually using. With a proxy service, there are a number of different options, but the most common is transparent, which means that the receiver knows that you are using a proxy service, and what your originating address is. This field is the one that tells the receiver what that originating address is. So! If you want to trick a website into thinking you’re in a different country, this would be the field to fill in.

How do I know what to fill it in with? You might ask. Well! The easiest solution would be to look up which IP Addresses belong to which nation, and then pick one in the country you want.

Okay, okay, that’s great, thanks for the huge lesson, but how do I go about accessing and modifying these headers? I’m glad you asked! It depends on your browser, but most browsers should have a plugin you can install to modify your headers. (Just google ‘modify HTTP header plugin’ and add your specific browser.) I’m using chrome, so I’m going to focus on that.

Here’s the play store, and the header plug in that I grabbed. First one, works great.

Okay, when you open it up, it should open in your web browser and look something like this. Click the blue plus symbol in the upper right corner, and it will pop up a new row under the headers.

Now, I’ve already filled this one out for Australia. The Action part lets you say whether you want to add, modify, or remove a particular header field. We want to add X-Forwarded-For, so click add, then fill in the values above. The Description box is just for your benefit, so I filled mine in to tell me what country my IP address was.

So, as many electrical engineers are well aware of, designing a circuit is not the end all be all of a product design. However, what most non-electrical engineers don't realize is the software and pieces that go into design and prototype of an electronic gadget. So for those of you interested in getting into circuit design but not sure where to start, here's my quick and dirty run through of each piece.

The three main aspects are the circuit design, the case design, and the PCB(printed circuit board) design. (There's of course also any required software design, but I'm not going to get into that on this post.) Most of what I'm going to discuss is design software that is available for these individual pieces (specifically the software I am most familiar with).

So, for the initial circuit design, any sort of spice software is great, since it allows you to run your circuit to test if it works or not, before you move on to anything else. Trying this before prototyping is usually a good idea. My recommendation for circuit simulation would be to use LTSpice, as it is an opensource spice software (AKA free!) and it is the Spice software of choice for the Oregon State University campus. Why is that relevant? It means Oregon State has written and posted on the internet dozens of LTSpice references, guides, and tutorials are all aspects of the software. So, beyond the general help provided for software on the internet, an entire electrical engineering department has posted plenty of resources. Type in "Oregon State LTSpice Tutorial" in google and see all the results. If you can't find a guide with your google search, add Oregon and suddenly there are more results.

Now, moving toward the case design. Why do I go over this before the PCB? Because generally you want your end product to be a certain shape and size. To this end you can design your project in any sort of CAD software. My personal preference is AutoCad. Why? Because AutoDesk makes all of their software freely available to students. All their super pricey design software? Free. You don't even have to be an engineering student. Just be a student. Awesome, yeah?

Another good option if AutoDesk is not your best friend is SolidWorks. Most engineering programs have a freshman level SolidWorks course, and both AutoCad and SolidWorks have a lot of readily available tutorials and references for new users. SolidWorks is not free to students, but most engineering programs offer it on their lab computers, and a quick search of the web shows that some university programs don't actually require a user log in to access SolidWorks over the VPN. So even if you're not a student you can get access to SolidWorks. (How do I know this? Google. Google is great. If your word search doesn't get what you want. Try slightly different words or word order.)

So, you have your shiny CAD software and you've designed both your circuit and your case? Awesome. Now go back into your CAD software and design a PCB that fits comfortably in your case. Make it its own part. Why? Because there is at least one PCB design software that lets you import PCBs you've made in a CAD program. (I know this works with SolidWorks, I have no tested it with AutoDesk Inventory, but it should still work. If you try it, and it doesn't, let me know and I can fight with it on my machine to figure out the steps for ya.)

Got your PCB shape? And your case and your circuit design? Awesome. There are a couple different PCB routing softwares available. The two I am most familiar with are Eagle (which is much cheaper) and Altium. Eagle is the poor man's routing software. It works well, though I'm not as knowledgeable about it personally, as I use Altium, since my campus provides it. However, I know that the electrical engineering department at the University  of Wisconsin - Madison does a lot with Eagle, and they have resources online as well.

So, to talk in depth about Altium, Altium also has circuit simulation capabilities. So if you want to design your circuit in Altium, cool, since you'd have to rebuild it in Altium if you design it elsewhere. Altium has two different sections. There's the circuit sheets, and the PCB sheets. You'll need a circuit sheet to start with, and then you'll add components and build your circuit. When creating the PCB sheet, you have the ability to import a design from a CAD file. You can give it details about the shape you want, but both SolidWorks and AutoDesk are much friendlier when it comes to 3D design, and allow more options. Once you've created your PCB, whether from import or not, you update your PCB with all of your components, They'll pop up next to the board, with little lines showing where each piece is connected to another. From there you put them on the board as you please, and then start the process of routing.

What is routing, you may ask? Well, when the PCB is printed it's more or less plastic(I am not up to date on actual materials of the boards, so please correct any errors here), with thin, small grooves dug in. These grooves are then filled with copper, and the grooves connect to the pads where the components are connected. So, when you route your board design, you're saying where you want those copper traces to be. Your board can be multiple layers thick, which allows for overlapping traces.

To those of you that are new, this blog is run by an engineering graduate student, with the primary focus of educating people on scientific topics, helping people with scientific studies or projects, as well as emphasizing the importance of critical thinking and validating information you receive to be sure it is not bias or incorrect.

I tend to post things now and again as I remember and time permits. I answer all asks about homework questions/scientific topics publically unless you request I do not.

Oh! Sorry this took so long to respond, tumblr just now let me know about it *shakes fist*

I think introducing them to a lot of aspects of sciences early would help. We tend to not touch on a lot of math until third grade (at least in the US) and science instruction is very limited until they hit high school, where then they have an option of avoiding a lot of science usually.

I think a big thing that would help is showing them cool things about it while they’re young, and getting them involved in their own projects. Things like FIRST Lego Robotics are a great example of getting kids interested in science and technology. However, programs like first aren’t very widespread, and I didn’t hear about it until I was already in college.

One way to combat this is to make it fun. There is the science portion of elementary school, but more often than not it’s either a video or a teacher talking at you. At a young age that tends to be really really boring. Make the science portion of the day into an interactive portion, so kids look forward to it like they do recess. Have them build interesting little gadgets and have them then explain to each other why they work. (A good example of this is the technology exhibits at the OMSI museum in Portland, OR) Hell, set up an area that’s part of “recess” where students can choose to build things, and have what’s available rotate over time.

Science is naturally interesting, and kids find it really cool, but if we treat it like “school” then it’s not fun. Turn it into a treat, so it feels like they get double recess during science classes, and during that time explain why things are doing what they’re doing with increasing detail as students get older. That way they also get a grasp of how to THINK about things. Science is just an exercise in critical thinking. If we drone at them they wont get anything out of it.

For those new to this, I am a nuclear engineer with a physics minor, who's taught chemistry, math (through calculus and linear algebra), electrical fundamentals, and physics to others at a high level. I'll also be teaching statics in the fall.

I'm starting my doctoral program in engineering physics this fall, and I'm currently working for Areva. (For those who are not aware, Areva is a French based nuclear company, who works in all aspects of nuclear energy (with some nuclear medicine as well!) as well as renewables.)

The purpose of this blog is to help others with any STEM questions they might have. I've previously posted my handouts for my students on this blog, and I'm happy to answer any questions I receive to the best of my abilities, complete with sources. I hope to those of you who read my responses you'll check those sources and verify that I've chosen places that are non-bias and proved technical and fact based information. If I haven't? Tell me! It benefits everyone if I'm informed, and my goal with this blog is to promote science, education, and critical thinking.

If there's any other chemistry topics giving people trouble, let me know and we'll get cracking on those too!

Yeah, huge jump from circuits, right? Well, this is what I've been covering in class recently, and it's crazy empirical. If you're a two phase heat transfer person, I'm sorry, I mock this mercilessly while going over the empirical correlations. Please bear with me!

So! In one phase models there are some empirical relations, but the equations and solution methods are originally rooted in the first principles of physics (conservation of momentum, energy, mass, you get the idea). However! Two phase fluids make using first principles difficult, simply because there are so many variables, and then the fluid flow for two phase systems is also difficult to predict, so that can't even be used. But! This is kind of long, so the run through for saturated boiling two phase heat transfer is under the cut!

Okay, here's my brief explanation of phasors for my lovely anon. (Sorry it took so long!) I'm not sure if you had any specific issues or examples you wanted me to run through, but I would be glad to run through anything more specific with them.

Now then, since the whole reason for using phasors is to make math easier, we have operations for each of these forms, and obviously different forms work better for different operations.

Mostly I wasn't quite sure what specifically was confusing you with them, but here's the basics of them summed up. I used the 4th Edition of Fundamentals of Electrical Circuits by Charles K. Alexander and Matthew N.O. Sadiku, and their section on phasors begins on page 376.

Okay guys, for those people who aren't aware of this. If you are a college student (any discipline) AutoDesk offers you their software free of charge until you graduate. It is FANTASTIC. If you're in any sort of engineering discipline, or have an interest in professional designs for projects, this is software you probably want to use.

Their student portal is here.

Okay, now were's going to first go through source transformation, and what these circuits look like.

Following this we'll look at finding these values in larger circuits and across specific points