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Comment: Re:Moisture inside the dam wall (Score 1) 168

by theguyfromsaturn (#46380209) Attached to: Damming News From Washington State

Not sure what you mean by water "invading" earthen dams... but just for the record, earth dams are always full of water that seeps through the component soils to one degree or another. High flow (in cracks say, or because of overtopping) is a problem at it will cause erosion, which may eventually lead to failure, but water "invading" them is not a problem, it's a given.

That being said, you are correct in mentionning that concrete actually requires water to harden through hydration. The problem with cracks in a concrete dam, is that they propagate, and the pressure of the water will certainly help them do so.

Comment: Who needs a fleet of snowplows? (Score 1) 723

by theguyfromsaturn (#46130253) Attached to: Atlanta Gambled With Winter Storm and Lost

The problem is one of planning not of vehicles. Where I live, snow is a common occurrence every winter, certainly during the warmer days of winter.

The city does have a fleet of snowplows, but when a heavy snow falls, it's not the city's snowplows that handle the load but the graders and other earthmoving equipment of the local contractors. While graders are better with additional pusher attachments, just the basic blade will do wonders.

The main thing is getting organized so that the city can mobilize quickly the equipment of the local contractors in times of need. While it is always costly to hire those guys, it's certainly less costly to do it this way than purchasing your own fleet of vehicles that will rarely get used. Graders get used all the time.


Comment: The only improvement needed in laptop keyboards: (Score 1) 459

The only improvement laptop keyboards need really bad, is to be swapped with the touchpad. When I use a mouse, I very naturally extend my hand to do so. When I type, I tend to naturally rest my wrists on the table immediately in front of the keyboard. When I rest my writs on a #!@!%$#@! laptop while typing, the cursor goes wherever on the screen and very unfortunate things happen. Actually keeping my hand closer to me to use the touchpad feels unnatural. Why are they designe this way universally? I never understood. A layout with the touchpad above the keyboard instead of below it would feel much more natural.

Comment: Re:oh come on (Score 1) 375

Indeed. It's not even a new concept. My first contact with the concept was as a child (in the 70s) watching an old James Bond movie (probably from the 60s, with Sean Connery, I don't remember which one). The only difference is the actual visualization of the concept. I got all excited when I thought the device actually existed as a prototype. It's not only a concept, but a concept that is still in wait of breaktrhough technologies to happen as I understand it.

Comment: Re:underground stuff is still really poorly mapped (Score 1) 141

by theguyfromsaturn (#45870943) Attached to: Object Blocking Giant Tunnel Borer Was an 8" Diameter Pipe

Most stuff actually is fairly well recorded "somewhere". No work gets done without getting locates before (yellow, orrange, blue lines etc), that are generated by surveyors based on both as-built plans, and confirmed on-site from geophysical investigation instruments, be it metal detercors or ground penetrating radar etc.

After something is installed you have to provide detailed plans of location depth etc. usually in the form of drawings (both plan and profile for line structurese such as utility pipes or cables). Tables with coordinates and elevations may be sufficient for more compact objects. And you have to do a survey for the as-builts, the original plans are not good enough for final submission. (That is for any project of any magnitude that will require city approval... what people do in their backyard won't be covered).

What often happens is that (as in this case) something is there, and reported the site investigation report, but its presence goes unnoticed in the volume of data looked through when working on the project. Or it was noted originally, but the alignment of the tunnel was different and it was not a concern, but a last minute change in alignment makes it a concern and people (being people) just forget there was somthing there to consider, because they HAD checked those things before after all, and already figured out there was no concern.

Of course, whent thing are very old, the problem is often getting access to the documentation. Either it was done in a time when records were not kept as thoroughly, or the they are just very hard to track down for one reason or another. Usually, if something does require city approval though, you can find those submissions... and as long as nobody bribed a city inspetor to look the other way while corners were cut , they should provide a reasonable estimate of where things are. The main difficulty is actually tracking down all activities that may have been undertaken at that location over time. While the record may exist, making sure that all things that were done (as owners changed over time) are considered may be challenging depending on the data tracking and storage implemented at the city level over time.

Comment: Re:Show time (Score 1) 722

by theguyfromsaturn (#45254507) Attached to: Google: Our Robot Cars Are Better Drivers Than You

I've seen most of my friends drive (I don't drive myself so I can be a more objective 3rd party observer) and I have to say I'd welcome self driving cars any day. Most people frequently are distracted while driving. In 99.9% of the time (yes statistic made up on the fly) nothing happens because nothing out of the ordinary happened at that particular moment. Our built-in autopilot copes very well with the routine events. But change that in any significant manner and accidents are imminent. I have no doubt that self-driving cars are more effetively aware of their surroundings most of the time.

It's funny how most of my family and friends consider themselves good drivers. Having been in close calls the very few times I have been riding with each of them I find it quite scary. It's actually quite amazing that there are no more accidents on the road each day. i have sample only an infinitesimely small amount of each of those people's driving time, and the frequency of the close calls doesn't fill me with confidence about their general level of distraction. And, I repeat, ALL of them consider themselves good drivers. Food for thought.

I for one welcome our self-driving vehicles. The roads can't possibly be less safe with them.

Comment: Re:No wonder ... (Score 2) 384

by theguyfromsaturn (#44351593) Attached to: The Book That Is Making All Movies the Same

Just in time for Transformers. That movie really looked like a formula movie (without a plot). Interesting to note it came in 2007 and felt like junk right of the bad. It had all the elements of "successful" movie, the inadequate boy... who meets the hot girl, pointles fights here and there. Oh yeah, did we mention the hot girl bending over the open hood of a car? Shouldn't miss that. So the bullied boy... oh yeah and the awkward parents who are actually happy to see that he'd been sneaking a girl in his room.... a puppy peeing on somebody. Oh, yeah car chases, you can't have a blockbuster without at least one car chase. And of course, giant fighting robots to add what most wouldn't have.

All they missed was a plot. But they definitely had everything else in the recipe book.

I never understood its success given the lack of plot, but apparently the book was right. Form trumps content anytime. (but really, was a little bit of a plot linking the different ingredients that much to ask? I didn need an Oscar winning plot, just the kind of plot that gets childrens books going).

I know the continuity (or lack thereof) will offend some sensibilities. I appologize for this, but I was trying to convey my state of mind as I was watching that disaster unravelling before my eyes.

Comment: Re:Prior art (Score 1) 322

To answer your question as to "rebar corrodes", I should point out that cement is generally basic. Actually, Portland Cement can be quite basic which tengs to cause some unwanted reactions with the silicate aggregates. Still, a high PH will generally tend to protect the steel from corrosion. The salts used in de-icing salts will tend to have a low pH which will foster corrosion of the reinforcement make it expand, which causes cracking of the concrete and accelerates the influx of water to the steel which accelerates corrosion etc.

Recipes such as those used by Romans are already known (the contribution of t he paper is more as to why that is, than that it is the case as various types of ashes are used in different mixes). Replacing cement by addititives can give some properties that are good in some cases, but may make it take longer to cure, and/or reduce its ultimate strength (depending on the additives). Choosing the peroper mix depends on the usage and the cost.

As to why reinforce at all, it's because we need reinforcement for tensile strength. Concrete has a fraction of the tensile strength than compressive strength (think of a chalk) . As mentionned in a previous post, Roman works relied more on compressive strength than tensile strength. There are advantages to that approach, but definitely many practical disadvantages.
