Posts by Richard Grevers
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I've worked on and off as a pyrotechnician since the 1980's, and was (I let it lapse as there isn't enough work around the 'naki) licensed to rig and fire star shells up to 250mm.
My reaction when I read that a woman had been gashed by a flying bit of metal was, quite literally "what the fuck?". You don't use metal anywhere near fireworks of any sort. The product is encased in cardboard/paper. The mortars are usually heavy cardboard tubes, and occasionally suitable types of plastic (those which will not disintegrate in a brittle fashion, often fibre-reinforced). And this incident is exactly why - mortars will explode from time to time, and metal is the basis of shrapnel bombs.
It's rule two of pyrotechnics (rule one is never, ever, put your head over a mortar, loaded or not.) -
Hard News: Dirty Politics, in reply to SHG,
This might have been said in the ensuing 350 comments, but here goes:
When you have a low-traffic website on shared hosting (like 95% of NZ small businesses), your hosting provider diverts email to a separate server (or brigade of servers) called an MTA. Prior to 10 years ago, many shared hosting setups did proces sand store mail on the webserver, but it turned out that big waves of spam email were more likely to overload a server than any website problems. The company I worked for was busy transferring mail to MTAs in 2006-07.
However, once your website outgrows shared hosting and requires a VPS or a dedicated server (we’re talking $50-$500/month, more for a managed service), you no longer have access to the MTAs. You either have to stump up with more $ for a separate VPS to host your email, or simply take advantage of the email hosting built in to the Control panel of your webserver, which of course gives no warning that this might not be a good thing to do. Setting up an MTA requires a fair bit of nous – there aren’t the click-and-easy solutions that abound for website hosting. -
Hard News: Over the paywall?, in reply to Richard Grevers,
must.read.rest.of.thread.before.replying
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Hard News: Te Reo Māori in schools:…, in reply to Bart Janssen,
Just a comment about learning second languages. It is a myth that children learn languages faster than adults.
That's a very dated paper, Bart. My wife has studied child language acquisition, and more recent research shows a significantly increased language learning ability which disappears by age 11 (I would offer some links, but alas, she has just driven off until next week!). Furthermore, if a child starts school with a significantly underdeveloped first-language ability, the best thing you can do is teach them a second language, as that triggers a "second-chance" process that puts all the missing blocks of first language ability in place.
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Hard News: Over the paywall?, in reply to Stephen Judd,
So there are very strong incentives to get up a story as fast as possible (ie with minimal subbing and checking) and then update it continuously. Once readers know a story will likely develop over the day they’ll keep refreshing.
The problem being (on Stuff, at least) that the way they update is to bung a new short story at the top of the article and make no effort to integrate it. I was reading articles on MH17 which gave the same background facts four times - obviously because they had "updated" the story three times without reviewing what was already in the story.
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Paywalls imply a significant vendor-lock-in. I'm in Taranaki, so the Herald misses a lot of relavant news for me, but there are times it way outperforms stuff on breaking stories. But I'm not going to pay for both. (And I'm certainly not prepared to pay for stuff based on the abysmal quality of their android app story selection).
The biggest problem is that, more than a decade after it was mooted, we still don't have a workable micropayments system ($0.08 to read this article), and I suspect that the main reason for that is that micropayments would show up how excessive the banking system's transaction fees on non-micro payments are.
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I can't give any direct comparisions since we are several km from the grid. Our hot water is wetback off the kitchen range supplemnented by a doesn't quite work well enough (water pressure too low?) gas califont. From older phhotos the house used to have solar h/w - presumably it was removed when it broke down (I know the cylinder has been replaced since then).
So while it would be nice not to have to run the fire in summer, our savings would be hard to calculate (what is the cost of our labour in harvesting and storing firewood) - and we spend so much time "in the cloud" during winter that annual solar energy gain is greatly reduced.So: General thoughts:
In general, heating water and storing it isn't very efficient. However, the only fuel source fast enough to run a zero-storage system is gas - which would have been a great resource for several hundred years if we hadn't burned most of it to make underpriced electricity in the 80's and 90's. Neither solar nor electricity is fast enough for on-demand hot water.
The biggest cost component of solar hot water is the plumbing. This varies in complexity depending on water pressures and cylinder type. An ideal system uses thermal siphon, but some need pumping.
Solar may well not meet needs year round, so what is the winter backup going to be?
Last time I spoke to someone a chinese-made vaccuum tube unit cost $1200+GST landed. You could get about three decent sized PV panels for that price. So if your existing cylinder could be fitted with a 12-24V DC element, (I don't even know if there is such a thing as a cylinder with dual element options) PV direct to water could have lower capital costs (a controller triggered by a thermostat should be around $200, cable can be expensive if you can't keep distances short).
Excess PV can power other things, too, whereas SHW can only heat water.
Using PV in a grid-tied or battery storage system to power a 240V AC heater element would increase the size of inverter required ($$$) - which is why, in conventional off-grid energy design, water heating is the first thing you throw out of the electric equation.In our system, going back to Solar Hot water might be something as simple as branching the cold water feed to our HWC before it gets to the house and running it through 40m of alkathene pipe attached to a black concrete wall. If that raises the temperature of the mountain stream water by even 10 degrees, it's a significant fuel saving.
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remind me how we embed video again? Just the URL format doesn't seem to work. (Should it be in the mini-help below?)
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Hard News: The Language of Climate, in reply to Che Tibby,
otoh we need plastics, and they’ll have to be from oil or coal.
We have the technology - all it needs is for oil to get a bit more expensive to make the bioplastic investment attractive:
http://opensourceecology.org/wiki/Polyethylene_from_Ethanol - and also their wiki category on Bioplastics. -
Before I gave away my film SLR, I had a 1970's Toshiba 70-220 lens that was true macro - It could focus at 12mm and zoom at 50mm from the lens - which made lighting a real challenge, as I couldn't afford a ring flash, especially not for a lens with such a big diameter front ring.
I had picked it up cheap, probably because nobody could be bothered with such a heavy lens (it had its own tripod mount) in the age of compact zooms - it was probably $2000+ when new.