Follow Slashdot blog updates by subscribing to our blog RSS feed


Forgot your password?
Get HideMyAss! VPN, PC Mag's Top 10 VPNs of 2016 for 55% off for a Limited Time ×

Comment Re:Give option by default (Score 1) 163

Given that parents didn't have an equivalent to an ISP filter for books that I read and television that I watched when I was growing up, why would they need their kids to have a professional babysitter now? If the kids must have a computer in their room and not the family room, surely there's a simple way to configure a router / firewall PC to show all web pages going into the house in real time. Also, if it's basically a censorship blacklist, I wonder:
1) What else might end up on it "by accident" and therefore unavailable to everyone who doesn't tell their ISP "gimme porn"
2) How they expect to get every porn site in the world on it when new sites of (all types) get registered all the time
3) How long before the general public hears about proxies (for parents, probably about a year or so after their kids have been using them if they the government to do their parenting, I expect)

Comment Re:Why I doubt driverless cars will ever happen (Score 1) 604

A flying Johhnycab, maybe? I'd say that's better than a flying car in the 70s future sense, but agree that it won't be like we've thought of a flying car since they were first suggested. Then again, a lot of the future hasn't turned out like we've thought it might. One important holdup for flying cars will be a reliable source of energy - petrochemical fuels are getting too expensive for ground travel let alone a load of extra air travel as well (on the assumption that the flying car would use more fuel than the ground car for the same journey). Some people / authorities would be able to run them, but the future's looking more Blade Runner than Buck Rogers.

Comment Re:They're Missing Some Fundamental Considerations (Score 1) 179

First, we're dealing with plants, so photosynthetic efficiency is 5% if you're lucky (photosynthesis sucks for efficiency - chlorophyll is green, not black for a start). Sure, that's mostly for producing sugars and amino acids, not lipids, but that's what the algae do at the start of their life cycle. Given that the trial farms are mostly in the open in temperate or tropical climates, there's enough sunlight and looking at photosynthesis isn't going to make any difference (Solazyme use azooxanthellae algae that get their energy from sugar and not the sun, but I think that's mistake - we'll see how it goes)

Second a load of work has been and is still being done to see when and how much nutrient stress to place the algae and what else, like calcium carbonate, to add at just the right time to maximize lipid growth and whether any of a couple of hundred strains (a small proportion of all existing, I agree, but they're the ones that look most likely to produce over 45% mass lipids) has properties that make it worth spending an extra day increasing the cell size before nutrient stress to make lipids. In general, make lipid as soon as possible is the finding - the extra cell size generally means proportionately less lipid

Third, Amino acid market? google spirulina protein powder. As a western nutritional supplement it's been around for a few decades and as a part of the diet in some parts of the developing world, the dried algae has been consumed to provide most of the protein for generations. Some poor parts of India have the longest standing algae farms - basic raceways making food for people.
This gives you some idea

Fourth, I agree about reducing the use of fertilizer and not only because of efficiency of utilization in algal photosynthesis (I don't even know if it is), but because farming generally squirts fertilizer onto ground and hopes some of it will be used before being rained away whereas algae farms put fertilizer into the water knowing that it will all be used. Getting most people to eat it as a major part of their diet or farmers to use it as feed will require a bit of a cultural shift, but the tech has been in place for ages

Fifth, water will probably be waste or reused in a PBR so no or minimal ongoing cost, NPK could well be waste if an algae plant also treats sewage so no cost. The carbon boost could be provided by other sources of carbon - calcium carbonate is a waste product of water desalination plants, so would be a good option in some cases. I don't see that photosynthetic efficiency is a game changer unless you're thinking of growing in the arctic circle, but area of land or water (as in Jonathan Trent's omega project) is going to have to be big.

Comment Re:Sewage (Score 1) 179

My belief is that waste water will be the only long term success for this, but there are plants either being proposed, set up or already existing in deserts that use mined or otherwise created nitrates and phosphates and even (in a minority of cases, I hope) allow water evaporation - in the kind of places where water is likely to evaporate very quickly. After that, there's the task of getting the oil (or lipids, as the algae people call it) out of the cells, for which there are several techniques, all of which use energy - hopefully most of this could come from photovoltaics or something similar, but I expect that there are some that use fossil energy to separate the oil from the rest of the cell.

As for using waste water plants - I expect that there would have to be some re-engineering of current plants, but not necessarily completely new ones built - where there are plants already in place. Where there aren't, it will be a while before anyone sees any profit in building one to make algae oil and then there's the problem of where to get the land to build them on - I don't see a new one being built in Manhattan, for example. Trent's project (omega or something like that?) gets round this for coastal areas (like Manhattan) but there's a lot of places that doesn't apply to.

I don't know how we can expect to filter runoff without causing major changes to river flows and by extension ecosystems, but as it's basically free nutrients, people should definitely be working on it. It's still early days for the whole industry, so most of those setting out now will fail but I expect a few will succeed and they will have a formula for how much oil they can make consisting of elements such as:

1: How much in the way of nutrients that are currently being thrown away does an algae cell need during its lifetime
2: How much of these nutrients are currently thrown away in sewage / runoff / farming / mining waste (I don't know that the latter two happen, but just in case)
3: How much water is freely available to support the maximum amount of algae that 1 and 2 suggest can be grown - you're right to think that it doesn't need to be clean water and there may even be strains that clean water with small amounts of industrial pollutants in
4: How long before each generation of algae produces enough oil to be worth extracting it (about a month, maybe)
5: How easy is the oil to extract, giving
6: how much oil a month can be made

This, combined with how much the oil will sell for will give a clear idea of how much money it's worth investing in a new algae / sewage / whatever plant or re-engineering what's already there. So far, most of these decisions seem to have been made based on what has been done in labs, but with people like Solazyme charging vast amounts for their diesel (admittedly, most of what the US Navy have paid for is further research, but it still looks like thousands of dollars a liter of diesel) you can see that this is still in the research phase and even though it's being treated as the next gold rush by some, it wouldn't be research if we knew where it would end up.

Comment Re:I wonder (Score 1) 248

I hope it wastes less energy, but converting energy from one form to another always loses energy and this sems to add two conversions to the current system, so I don't know how much more efficiency can be expected. Did anyone see figures on efficiency in the article? I only skimmed it.

I can see this having a better future with renewable energy like solar, so that lights that are on at night can be powered from grid-supplied solar energy or wind energy when there is no wind. For solar, it would have to be at least equal to something like heating salt during the day to give the energy back through steam powered turbines at night, so again some numbers on efficiency would be useful

Comment Re:Now there's an idea (Score 1) 153

Most (if not all) UK sewage plants already use their methane (and biodegrade their "incoming product" to make more) to make electricity, up to (I think) 40MW for a big plant. Some landfills are even doing this, but again it's not enough to compare with a power plant (if I'm right that a regular power plant outputs 1/2 - 1 GW)

Comment Re:Nest & Tankless heater (Score 2) 281

Agree with keeping the tank if possible - especially if your geekery is likely to extend to environmentally friendly (or keeping the bills down) and you have roof space and / or garden for solar thermal water heating - the warm water will need a nicely insulated tank to stay warm and a bunch of solar thermal tubes (or a self engineered system for more geek points) could be just as good a talking point as living on the bridge of the Starship Enterprise

Slashdot Top Deals

"We want to create puppets that pull their own strings." -- Ann Marion "Would this make them Marionettes?" -- Jeff Daiell