How to Build a Computer Pt. 2

So last time we had a basic skeletal system, now we put the flesh on it. So, you want:

A Case


This is where all the other stuff goes in to. You'll screw in the motherboard and the power supply, and viola!

An SSD/HDD



This is the storage of your computer. You'll install your operating system (Windows/MacOs/Linux) on it and be in business. As hinted by the title and picture of this section, there are two major options.

Solid State Drives (SSD) are the newer option, and are a lot faster and smaller (both in physical size and in memory). You might be able to get a 250 GB SSD for the same price as a 1 TB HDD. If your desktop/laptop still uses an HDD, upgrading to an SSD primary drive is one of the most significant performance boosts you can see.

And just in case you didnt know:

1 MB = ~1000 KB
1 GB = ~1000 MB
1 TB = ~1000 GB

Also, MB means "Mega Byte" and Mb means "Mega Bit"

1 MB = 8 Mb

Your internet provider quotes you speeds in Mb, your file sizes are reported in MB.


A Graphics Card


If you're a gamer, this is where you'll spend your money. Not a whole lot to say here, just make sure you motherboard has the right slots (watch PCI Express vs PCI Express x16) and get a card commensurate with your wallet and dreams.

Conclusion

And that's it! Stick it all together, be gentle so you don't snap anything, and if you have a static problem make sure to get grounded before working.

Of course, you'll need a mouse/keyboard/monitor and probably some speakers. Also maybe a DVD writer/reader. Also, a copy of your operating system.But once you've got it set up, you'll be set! Next time you want to upgrade, you can swap out components and not have to buy a whole new computer.

How to Build a Computer Pt. 1

Let me preface this with a statement that I'm not building a computer, and so won't have handy pictures of how pieces fit together. But! I am here to tell you that if you know how to snap a couple lego block together, you too can build your perfect pc. For cheaper than a pre-assembled gig.

Why would you? Well, besides getting a more powerful computer for cheaper, and then the option to upgrade it incrementally, you also get the satisfaction of knowing you built one of your most powerful tools with your bare hands! Ok, maybe wear gloves.

First, if you're really lost on all this but do want to give it a shot, here is a great resource:

http://www.logicalincrements.com/

Lets get started. The main things thing you'll need is..


A Processor


The processor (aka CPU) is the brain of your computer. It's responsible for executing any programs/calculations your computer calls for.

How do you pick one? Well, most modern CPUs are more than powerful enough for basic use, and even gaming. The CPU doesn't tend to be a bottleneck for most people. So, if that sounds like you, get a nice mid-range CPU and call it a day. If you're going to do a lot of video editing, simulation running, or you just really like talking about how many Gigahertz you have, get a beefier CPU.

Just know if you get a real beefy CPU and put it through the ringer, you definitely want a nice heat sink so that your house doesn't burn down.

Just remember, there are two main types (AMD and Intel), and within thoe two types are different "socket types" of CPU. For example, AMD uses AM1, AM2, AM3, AM3+, etc. You'll want to note what type yours is so you can pick the right..



Motherboard



The "heart" or connective tissue of your computer. A motherboard is what you snap all of the other pieces into, to have them communicate with one another. Typically, a motherboard will have a lot of stuff built in so you don't have to worry about it. For example, sound cards. ethernet controllers and USB are all standard motherboard features.

Additionally, if you're not much of a gamer, you can find motherboards out there that have built in graphics cards. That'll eliminate a major cost and simplify your build.

Also, note that motherboards come in different sizes. This'll determine what size desktop case you can fit it in. So if you want to build a tiny shoebox computer, make sure you get a motherboard that'll fit into a microATX case, or similar.

Have a motherboard picked out? Great. take a look at its specs and find out what kind of memory you need.


RAM




Random access memory is high-speed storage that your computer needs to respond quickly to things you ask it to do. It's basically the same as your hard drive, but much faster. When you open a program that knows it's going to be running for a while, it'll request RAM space to store it's frequently-accessed features in.

RAM tends to be cheap and adds a good bit of performance, so my reccomendation is get the best memory sticks your motherboard can handle. Look for cache speed and capacity.

All good? Great, now we need..

A Power Supply



You need this to plug into the wall so you can power all those things in your PC. Don't pick this based on wattage, unless you're building a server farm or something. Instead, do some research and find a brand your comfortable with. I like Corsair. Look in to efficiency.

If your power supply fails, the rest of your computer can become a nice paperweight, so pay attention here.


The Rest

Now, theoretically, if you've got all these components (and the motherboard has a built in graphics card) you could snap together everything and power it on. You won't get much besides a BIOs screen, but hey, its a first step!

I'll talk more about what you need to finish up with a sweet PC next time 'round.

Reactivity Coefficients

Today I'm going to talk about one of the natural safety features of a nuclear reactor, the reactivity coefficient. First, lets define reactivity:

Reactivity is the change that a reactor sees away from it's normal state. For example, if a reactor is operating and you insert control rod banks to shut it down, you are subtracting reactivity (or adding negative reactivity). If you are familiar with the "k" value, this is expressed as:


(k_eff - 1)/k_eff


So you could see this as the deviation of "k" away from 1 (critical).

There are several different reactivity coefficients, which are basically just measures of how the reactor responds to certain changes in the system. For example:

The moderator temperature coefficient is a measure of how much reactivity is gained or lost when the moderator (usually water) changes temperature. In a typical nuclear reactor this is a small negative number. What that means is that when the moderator temperature increases (a positive change) you multiply it by moderator temperature coefficient (a negative number) to see what the change in reactivity will be:

+ Change in moderator temperature * - change in reactivity/change in moderator temperature              = - change in reactivity


Thus an increase in moderator temperature would decrease the overall reactivity of the system. Similarly, the fuel temperature coefficient (also known as the Doppler coefficient) measures the change in reactivity based on the temperature of the fuel. This is also an inherently negative number, which is important because the fuel is the first area to see temperature changes.

Finally, the void coefficient is a measure of the reactivity change versus the change in voids (meaning areas of no moderator). This is best known as one of the causes of the Chernobyl incidents. The Cherynobyl RMBK reactor had a large positive void coefficient, which meant that when it began boiling (creating voids) the power began to go up. With more power comes more boiling, creating a feedback loop that ultimately melted the core.

Reassuringly, in the U.S.A all of the nuclear reactors in use have a negative void coefficient, meaning if boiling (or a loss of coolant) ever occurred, the natural tendency of the core would be to shut itself down.

Nuclear Plants on Fault Lines pt. 2

Last post we talked about the existence of fault lines, and saw that a handful nuclear plants were in some in areas of a high-eathquake risk. Now, we'll talk about what it means and how it's mitigated.

The Effects

True to the name, earthquakes produce a vibration of the ground, shaking the earth along with everything that resides on it. This means water (the ocean), buildings, people, cars, etc. The quake itself isn't typically the most damaging effect of a large-scale seismic event, instead after-effects (tsunami's, fires due to electrical line failures, floods, landslides, etc) are the biggest cause of fatalities.

Mitigation

Modern building designs take earthquakes into consideration, commensurate with the location the building is being constructed in. Typically, superstructures (skyscrapers, large bridges, dams, etc) receive the most attention and research. However, there are earthquake codes for all sizes of human-occupied buildings.

One example of a mitigation techniques involves bearings (eg rubber-lead blocks) built into the base of a structure to isolate the top  part of the of the building from the bottom. This is called a "base isolation system." Another system includes dampers built into buildings which absorb vibrations. For example, this pendulum damper built into the top of the Taipei 101 skyscraper:







Regarding Nuclear

As mentioned in previous posts, the nuclear industry is no stranger to stringent safety regulations and policies. This holds true in regards to earthquakes, especially since the 2011 Fukushima event. Specifically, nuclear power plants must by law take into account:

• The most severe natural phenomena historically reported for the site and surrounding area. The NRC then adds a margin for error to account for the limited historical data accuracy;
• Appropriate combinations of the effects of normal and accident conditions with the effects of the natural phenomena; and
• The importance of the safety functions to be performed.

- The NRC

Thus, plants design and implement earthquake mitigation features based on their location. For example, the Diablo Canyon plant in Calafornia (which as we saw had a high risk) was built to withstand 6.75 magnitude earthquakes, later upgraded to 7.5. The plant includes seismic monitoring systems which can initiate a SCRAM (reactor shutdown) in its repertoire of safety features.

Plants in less seismically active areas typically rely more on their already existing plant safety features, i.e. reactor shutdown/coolant/containment systems.

Finally, the NRC has published public documents for every plant in the U.S. detailing a safety inspection conducted after Fukushima, for public perusal at:

http://www.nrc.gov/NRR/OVERSIGHT/ASSESS/follow-up-rpts.html

Nuclear Plants on Fault Lines

Recently, I ended up in a conversation about nuclear power with a person outside of the field. As these things go, the first reaction was "that's a scary thing". What surprised me was that his first thought was that "a lot of nuclear plants sit on fault lines."

Now, I wasn't aware this was a concern. In afterthought it makes sense that nuclear in relation to earthquakes would become a topic after Fukushima. So, I did some research.

First:  fault lines are areas of increased earthquake activity, due to movements of the earth's upper crust (which "floats" on the earth's mantle). When separate pieces of the "crust" smashes into each-other, earthquakes result. To get an idea of where major fault lines are in the USA, take a look at this map:

Second: we want to know how many reactors are in fault areas. So, let's superimpose the reactors:

Right off the bat, we can see that the majority of reactors are built in areas with moderate or low earthquake risk. However, there are some plants of particular concern, from this source:

Two reactors at Diablo Canyon, (near the town of San Luis Obispo, CA) are 3 miles from the Hosgri Fault line and about half a mile from an offshore fault line scientists discovered in 2008. 

Two reactors at San Onofre (next to Interstate 5 between Los Angeles and San Diego, CA) are 5 miles from the Newport-Inglewood-Rose Canyon fault.

 Two reactors at the Indian Point, NY nuclear power plant are one mile from a recently-discovered intersection of two active fault lines. Close to 10 million people live within 25 miles of the Indian Point facility. 

These plants also have the added danger of being coastal, meaning that in addition to the earth shake, Tsunamis are feasible. 

I'll talk about what the industry does to protect against earthquakes in my next post.

Au Natural

For anyone who likes nature and all things beautiful, here are a great series of BBC documentaries that you may have missed, all narrated by David Attenborough:

Planet Earth



The first high-definition BBC nature documentary, also the most expensive commissioned at the time. It focuses on the various biomes of earth, and shows amazing geographical features as well as their wildlife inhabitants.


 






Life



Life is similar to Planet Earth, but focusing on wildlife and it's balance. Generally, episodes follow a specific category of life (eg reptiles, mammals, birds, fish, plants, etc) and highlight stories within each.

Human Planet



As you might expect, Human Planet emphasizes our own existence on earth, and our relationship and adaption to nature. Each episode focuses on different environments that we sapiens have made our home in, which is to say, all of them. Of course, there are environmentalist messages scattered throughout, but as a whole, the series retains the beautiful natural storytelling of Planet Earth and Life without becoming preachy.

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If you've never seen any of these amazing documentaries, please do check them out, they are really fantastic.