Yesterday Kevin bought a camera for his desk computer, and then we set up our Skype accounts. Not necessary that one but something along that line. Personally, if I were looking to buy another right now, I'd probably be tempted by something similar to this. I suspect my bottleneck is my ISP so even though I run a cheaper computer, I pay for the fastest connection I can afford. It's an old(?) Compaq with a 2600 MHz 64 bit AMD Athlon(tm) Processor LE-1640. It also serves a single public Shoutcast stream. Such as serving video to my bedroom netbook-TV setup. It also runs a web server but it's mostly for my own light use. Using a high-def TV as a monitor, its time is spent mostly streaming videos from the net and playing my old TV/movie collection. My other desktop is used as a personal server. It cost about $399(?) at Walmart without monitor. It's an Acer with a 3.1 GHz 32 bit AMD Athlon(tm) II X4 645 Processor, 4 gig ram and a 1 terabyte drive. At the time, I was too impatient to shop around. This computer does have a quad core but it just happened to be the cheapest on the shelf when I walked into the store to buy one. I don't play games except Mahjongg, which is not cpu intensive. 95% of the time I spend on this computer is spent browsing the Internet, checking email, shopping, and researching. My usage is probably similar to yours Nancy. You can see that the weight to strenght ratio of these lightweight concretes is actually better than that of traditional concrete! I thought this might be an interesting addition to the discussion on lightweight concrete. Many of these mixes use silica fume, metakaolin, fly ash and slag in addition to portland cement to obtain strengths of generally around 1900 psi (about 703 kg/sq m) Traditional concrete generally has a unit weight of around 145 lbs/cu ft (2322.67 kg/cu m) and strenght of 3000-5000 psi (2.109*10^6-3.515*10^6 kg/sq m). ![]() You might note that 58 lbs/cu ft is lighter than water (62.4 lbs/cu ft). This is about 16 kg/cu m for those Canadians. All the mixes I have seen obtain unit weights of 58-75 lbs/cu ft. Our challenge is to make a strong, lightweight concrete. You might be surprised to know that in universities across the US and Canada, there are engineering students who participate yearly in a Concrete Canoe competition. ![]() I am currently a civil engineering student. Research suggests that Metakaolin is superior to silica because it has less problems cracking in lightweight concretes. ![]() I thought I'd chime in on some of the comments. I realize that this string is very old, but I was directed to it while searching for Metakaolin.
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