If you're a regular follower of Ludamus, you'll have noticed that the site has been flat on its electronic back for a while.

I did think of saying that:

• the conflubulator had sprongulated the Ackermann widgets
• the Ludamus cat had walked on the keyboard
• a freak storm had taken out the entire continent where the server was based

but the real reason is simply stupidity on my part.

"Against stupidity the gods themselves contend in vain." (Schiller: The Maid of Orleans)

We're back in action now, and propose to amble towards no particular goal at our usual leisurely pace.

Here's a nice example of word order problems:

"The brothers, who both lived in Desborough Road, chased intruder Walid Salem, leaving him with a permanent brain injury after he was hit with a cricket bat so hard that it broke into three pieces."

(From the BBC News site at http://news.bbc.co.uk/1/hi/england/beds/bucks/herts/8468773.stm

Ludamus wonders whether a softer cricket bat would have broken into even more pieces. Still, it's only the BBC.

Have you ever wished that you could make that plastic bookcase shelf support that nobody seems to have in stock, or that bracket that holds the underside of your chair together? You can now build a machine which will print objects that you need.

Adrian Bowyer and his team at Bath University have developed Mendel, a relatively cheap device that you can build yourself for about 350 euros. Mendel, in turn, can be programmed with instructions to form a whole range of 3D parts in plastic. Examples of these are a pair of child's sandals, a door handle, a coat hook and a cocktail glass.

Even more intriguingly, Mendel can manufacture about 50% of the parts required to make a second Mendel, and the design team's goal is to improve this ratio. Ideally, one day, a Mendel (or its successor models) might be able to make a complete clone of itself.

 We might see a world one day where manufacturing small scale items is done at home by replicator machines, and where this kind of work becomes once again a home-based process rather than one conducted in vast mills and factories.

 "[RepRap] has been called the invention that will bring down global capitalism, start a second industrial revolution and save the environment…"

The latest gig organised by Singing Knives is at the Archipelago Works Gallery, in Sheffield. Come along if you're free.

Wind turbine photo by g-hat

Don't buy the green claims made by big power companies? Here are some tips to help you choose a 100% renewable electricity supplier. Switching to a green electricity tariff regularly makes those lists of ten things you can do to save the planet. So what's involved?

What does renewable electricity really mean?

Buying 100% renewable electricity means you get power that's generated only from sources like wind, solar, waves, tides or even biomass — and not from coal, gas or oil. Of course, the national grid means all the electricity in the UK comes from one pot — the watts my computer is using now could be from any fuel. But different suppliers contribute different types of electricity to the overall fuel mix. So you can choose to give your hard-earned cash to a company that doesn't use any fossil fuels at all.

Where do I start?

First up, visit a comparison site like Green Electricity Marketplace armed with a recent electricity bill. Several of the major comparison sites, including uSwitch, also have an option to compare green tariffs. Green Electricity Marketplace is great because it explains the pros and cons of the different renewable tariffs, as well as just showing you the prices. It also comes recommended by Friends of the Earth. Once you've put in your usage and postcode, the site should give you options to choose from.

Choosing the right tariff

The only way to be sure you're getting 100% renewable electricity is to opt for a company that doesn't generate anything else. At this point things get a little technical, because it helps to know a bit about how the energy market in the UK works, but Ludamus readers should be up to the challenge.

The UK government is aiming for 15% of all electricity to come from renewables by 2020. To encourage this, it gives out things called ROCs — Renewables Obligations Certificates to companies that generate renewable electricity. Each year, every power company has to end up with enough ROCs to cover their share of the government's renewables target. So if you own a huge coal-fired power station, then to meet your target, you have to buy ROCs from a company that owns a wind farm and has some spare. 

Some companies don't sell all of their spare ROCs — they "retire" them instead. I wanted to buy electricity from a company that doesn't use any fossil fuels, and which also retires some ROCs. I only found one company that could supply my home office and meet these requirements: Good Energy. I also love the way they encourage you to generate electricity at home, if you can. But another supplier might suit you best.

Whatever you do, just make sure it's 100% renewable.

The Singing Knives gigs are back, and here's the latest at The Shakespeare, Gibraltar Street, London (See the poster). This time it's Ignatz, ES and Chris Forsyth.

The Large Hadron Collider, based at Cern, near Geneva, is a huge machine for investigating the deep structure of matter. It's designed to accelerate beams of heavy particles (protons in this case) round a ring, in two opposite directions, and then to smash them into each other at the tiniest touch off the speed of light.

In September 2008, cooling systems for some of the Collider's superconducting magnets failed, and their temperature rose, leading to a  loss of the magnetic field which is essential for controlling the colliding beams of particles.

This may not sound spectacular, but the CERN fire brigade were called out after a tonne of liquid helium coolant had leaked into the main tunnel (and it takes a lot of helium to make a tonne).

The good news is that repairs and checks are now coming to an end, and the collider is due to being tentative operations at low energies in November of this year. There will follow a gradual build up of the beam energy over the year 2010. Patience is a virtue.

Will we learn some of the deep secrets of matter and energy, or will the world be annihilated instead? Follow this column to find out (or not, in the latter case).

I hate getting electricity bills. Prices always seem to be going up, and whatever you expect the bill to be, it's always more than you'd hoped.

But I've found a way of getting the bills down that doesn't involve sitting home alone, in the dark. I've got a Wattson. This neat little home energy meter measures and displays how much electricity you're using at any moment, in W or in £. It glows in pretty colours and has attracted a lot of admiring glances from visitors since it arrived in our house.

The idea is simple: if you can see how much electricity you're using, then you'll stop wasting it. And surprisingly, it really works.

My Wattson sits on the bookshelf in our living room, and I can see it every time I come downstairs. I got a fright the first time my boyfriend turned the kettle on, as it shot up to 3000W and glowed an alarming shade of red. We switched from using the electric shower to one that runs off the gas boiler because we saw how much power it was using. We also tried going round the house switching everything off, to get the display down to zero.

Since Wattson arrived, we've saved around 20% on our electricity bills. The Wattson costs around £100, so we'll break even in just under 18 months. If you get really into it, you can download software, programme in the current price of electricity, and produce graphs of your consumption patterns. I just like the reassurance I get from the calm, blue glow it gives off when our usage is low.

Here's the BBC's famous "step-in" button. Hover over it and enjoy. It's fun if nothing else.

As the U.S. declines as a world superpower, to make way for China, we can still all derive some comfort from its homely wisdom. 

"Aim towards the Enemy." - Instruction printed on U.S. Army Rocket Launcher

"When the pin is pulled, Mr. Grenade is not our friend." - U.S.M.C. Training Bulletin

"Cluster bombing from B-52s is very, very accurate. The bombs are guaranteed to always hit the ground." - U.S.A.F. Literature.

"If the enemy is in range, so are you." - Infantryman's Journal

"A slipping trigger gear could let your M203 grenade launcher fire when you least expect it. That would make you quite unpopular in what's left of your unit." - Army's Magazine of Preventive Maintenance

"It is generally inadvisable to eject directly over the area you just bombed." - U.S. Air Force Manual

"Try to look unimportant; they may be low on ammo." - Infantryman's Journal

"Tracers work both ways." - U.S. Army Ordnance Manual

"Five-second fuses only last three seconds." - Infantryman's Journal

"Bravery is being the only one who knows you're afraid." - David Hackworth

"If your attack is going too well, you're walking into an ambush." - Infantryman's Journal

"No combat-ready unit has ever passed inspection."

"Any ship can be a minesweeper… once." - Anon Naval brass

"Never tell the Platoon Sergeant you have nothing to do." - Unknown Marine Recruit

"Don't draw fire; it irritates the people around you." - Your Buddies

"If you see a bomb technician running, try to keep up with him."