Green for the sake of it

It's nice that people are finally catching on to environmentalism, and its popularity means that even people who don't care about the environment take part just because it's fashionable. However, being popular means some companies only want to appear to care for the environment. The aim of this post is to point out things to look out for to see if a company is genuinely environmentally-friendly.

• The most common offense is using reversed/inverted text, or "knockout text". This is white text on a black background, like the font on this site. What's wrong with this? Well, unless they're printing using white ink (unlikely), what they're doing is printing all the black parts and leaving the white (text) blank. This uses a lot more ink. So they have to manufacture, transport and apply more ink, and it also makes the paper harder to recycle since de-inking is one of the steps in recycling. Of course, this website is exempt, unless you print it (see 3rd point).
• I'm all for using recycled materials to make new things, but this is only useful if the recycled material replaces new material. I don't like using beverage can tabs to make things like handbags for the following reasons: it's impractical - they catch on things and scratch things. Most of all, aluminium is highly recyclable and using it like that prevents it from being better used.
• A small issue, but some websites claim to use less power because they use white text on a black background, the logic being less light needs to be produced. Well, I thought of that a long time ago, when I considered using a black wallpaper to increase my laptop battery life. It doesn't work for LCD screens. LCD screens produce all the light first, then remove what isn't needed. The only way to save power is to reduce the brightness. It might work for CRTs though, but if you're still using a CRT, that isn't going to save much power.

I don't like biodegradeable bags - they occupy more volume, weigh more and most irritatingly, tend to flake into pieces without warning when you store them, dirtying all your stored plastic bags. I'm waiting for some references to back up my claims before putting them up there though. Apparently, landfills are designed to let things NOT decompose, because that would cause settling and release gases. In that case, there's no point using biodegradeable bags. This is even more true for incineration (and everybody who claims to care for the environment should know how where their rubbish goes). The only good use I've heard of for them is to hold organic waste e.g. food or grass, so the whole package can be composted.

Disruptive technologies

My use here is more broad than convention, but I can't think of a better term. I'm talking about new technologies/innovations that are so successful/popular that all companies eventually end up using them, regardless of who invented them.

• carbon fiber racquets
• variable valve timing
• multitouch
• optical storage media
• perpendicular recording
  

There are many technologies that claim to be like that, e.g. carbon nanotubes, but it's rarely obvious which technologies will be game-changers when they're just introduced. It usually takes a few years for a technology to show its impact. Some new ones that may or may not become widely used:

• dual clutch (sure they have good performance, but are they necessary in normal cars?)
• Audi's ultralight technology
• solid state drives
• unibody construction? (haha)

And of course, the beauty industry is FULL of these, probably because each company wants you to think their product is unique and exclusive, and so they can patent it. Some ingredients are quite common, so I guess they can be considered as well (or maybe they just have a good reputation and aren't patented, like antioxidants): AHA, tea tree oil, salicylic acid.

Quote about knowledge

I've been looking for this quote for a while. I like it because it explains why I like measuring things.

When you can measure what you are speaking about, and express it in numbers, you know something about it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind; it may be the beginning of knowledge, but you have scarely, in your thoughts advanced to the stage of science.

— William Thomson Kelvin

Sawstop safety saw

This amazing saw stops itself and retracts the blade when it detects contact with the human body!

http://www.sawstop.com/

Not what you think it does

I find the power schemes in laptops misleading, like "maximum battery life". They make me feel that they really increase your battery life, like throttling performance would, but what they really do is only adjust the timers before various parts shut off. This only works if you leave your laptop alone, but if you're actively using it, this won't make a difference.

Harder materials shaping softer

It seems to me a recurring theme occurring in engineering is how progressively harder and harder materials are used to shape the previous material.

For example, you want to build a plastic part using injection moulding. To make the mould, you need a material that is harder than the plastic at processing conditions. Maybe you use steel. To shape that mould, again you need a harder material, maybe a ceramic like tungsten carbide. It's the same with forging metals.

One thing in this chain is that as materials get harder and harder, they become more difficult to shape. The steel mould above can be made by drilling out unwanted material. However, the material for the drill itself can only be made into simple shapes, like rods, sheets, or most often powders.

Sometimes, we "cheat" and use heat or energy to shape the hardest materials. Some very hard materials can only be worked at high temperatures. Or we might use electricity, plasma or lasers to shape them, the energy being "infinitely" hard.

Does this mean we can't use the hardest materials without a harder material to shape them?

Misleading phrases

I came across what I think is the most misleading marketing phrase so far: "modified sine wave". This is used to describe inverters, such as those you use to convert 12V in your car to 230V so you can use a microwave in your car. The 230V you get from the sockets in your home is a nice, smooth sine wave, and most devices are designed to use this. However, when converting DC (in your car) to AC, it's not so easy to produce a sine wave, so cheap inverters use "modified sine wave". From this phrase, you'd think they start off with a sine wave then make some changes to it. If they already had a sine wave, why would they have to modify it further? This phrase is a downright lie! The inverter produces a square wave, and they should just call it like it is. It's like saying this post is in translated French! More accurate phrases would be:

• Simulated sine wave
• Modified square wave (if they did something further to the square wave)
• Not a sine wave

Another marketing lie is Dyson calling the Air Multiplier a "bladeless fan". It's not really bladeless, the blades are just concealed in the base.

The difference between voltage and current

When I first learnt about electricity, I didn't know the difference between these 2. It seems many people still don't. Here's an analogy to help:

Let's say you're buying a car. The salesperson says this car has a top speed of 200 km/h. You say, "I only want a car with a top speed of 70 km/h, otherwise I'd get speeding fines all the time."

Just because the top speed is 200 km/h, it doesn't mean you have to drive at that speed all the time. Current is like that. An adaptor rated at 2 A means its maximum is 2 A, not that it'll provide 2 A all the time.

Voltage, also known as potential, is something like force. Think of it as the height of a hill. The higher a hill, the faster you'll be when you roll down it. It doesn't guarantee how fast you'll be - that depends on how good you are at rolling. That's why it's called potential, it only tells you how useful it COULD be, not how it IS. USB, and most electronic devices are 5 V. Car power is 12 V, and so are most modems and routers.

Current, measured in Amperes (A), is your actual speed after rolling down that hill. Can you see that this depends on your shape? If you're a barrel, you'd be pretty fast. If you're an octopus, it'd have to be a really steep hill. I think we all have a natural intuition about our world that makes Physics very easy to understand if we learn to apply it.

Power, measured in Watts (W), is just the product of voltage × current (for direct current, for alternating current it's a bit more complicated). Think of it as how much potential there was and how much you used.

So what determines your "shape"? How does voltage become current? Resistance. Measured in Ohms (Ω), a lower resistance results in a higher current.

All this background leads to this: let's say you have a 5V 10W adaptor. Can you use it to charge a device that uses a 5V 5W adaptor? Yes. Why? The device only sees 5V. The device doesn't know how many W the power supply can support, unless it exceeds it. If you plug in a lower power device, it'll simply use less power. Having said that, some low quality adaptors' (non-regulated) voltage fluctuates - they only output 5V when a 10W device is connected, otherwise the voltage is higher. Something like the RPM of a car depending not only on your throttle position, but the load.
All this is according to theory, I take no responsibility for what happens as a result of you following this advice.

What kills? Current or voltage?
What kills a car's power or its speed during an accident? Obviously the power doesn't matter. Likewise, voltage alone won't kill (static electricity shocks are several thousand volts). It's when voltage causes a high enough current (which is actually quite low, compared to electrical devices) that it's dangerous.

Biomimetics - learning from nature

Nature has some very unique properties, and biomimetics is the attempt to copy them. Here are some examples:

Lotus leaf
The lotus leaf's special power is the ability to stay clean, despite living in muddy water. From this talent, it has become a symbol of purity.

Water harvesting (Namibian stenocara) beetle
http://en.wikipedia.org/wiki/Namib_Desert_beetle
This beetle has patterns of water attracting and repelling surfaces on its back to catch fog and drink it.

Gecko feet
The gecko's feet can stick to almost any surface, yet don't get dirty!

Sea cucumber
This can change the hardness of its body.

Spider silk
This is possibly the most famous, spider silk can absorb the most energy before breaking. It's quite impressive. Imagine a fibre strong enough to stop an insect in mid-flight, yet thin enough to be nearly invisible. Spiders can make this effortlessly, while to make this we need extreme control over temperature and pressure - and we haven't succeeded! Sadly spiders are cannibalistic, which rules out spider farms.

Butterfly wings
The colour of some butterfly wings comes not from pigments, but from destructive interference of reflected light, a bit like colour from a CD. Not sure what the advantage of this is over pigments though.

Dragonfly body
The dragonfly has amazing flight capabilities. Its body encounters up to 30Gs of force. Combat pilots require bulky complicated systems to help them survive the G forces their planes can easily apply. Dragonfly bodies have a liquid cushioning system, where the liquid flows to the side with the most G forces, and protects them!
http://www.newsweek.com/2001/05/06/the-dragonfly-suit.html

Flea rubber
Resilin, a protein found in insects, is very efficient at storing elastic energy and very resilient (can bend many times).
http://www.nature.com/news/2005/051010/full/news501010-9.html

The cycle of technology.

It seems that technology progresses in a cycle, and it usually returns to its starting points:
On older computers, parallel ports were faster than serial ports. Parallel ports were used for printers and Zip drives, while serial ports were used for mice. However, current computers have returned to serial with USB - Universal Serial Bus.
Long ago, graphics cards were PCI. Then, AGP was invented - specifically for graphics cards. Currently, AGP is being phased out and graphics cards are back to PCIe16.

LED screens are still LCD screens.

I wish to clarify something regarding LED screens. First, this is how an LCD screen works:

1. White light is produced
2. The light is selectively filtered
3. The remaining light forms the image

The LCD is involved in step 2. Electric signals are used to control how much light is allowed to pass through the LCD.

The difference between conventional LCD screens and LED screens lies in step 1. In traditional LCD screens, the light in step 1 is produced by a cold cathode, just like a fluorescent tube. In LED screens, the light is produced by LEDs instead. LED screens still use the LCD in step 2 - that means LED screens still have LCDs. Sometimes, LED screens are more accurately mentioned as "LED backlit".

The listed advantages of LED lighting are:

• Thinner - if the LEDs are placed at the sides of the display, it can be made even thinner
• Less power needed
• Cooler
• Achieves full brightness instantly
• No mercury
• Lasts longer

I'm waiting for LED lights to be available for homes!
It seems that LED screens are more environmentally friendly, but the liquid crystals used in LCDs are toxic. I wonder if Apple is planning to replace them?

A new type of screen, OLED, is different from these 2. In OLED screens, only the light needed is produced - there is no filtering. OLED screens are even thinner, use less power, have wider viewing angles and better contrast ratios. They can also be made flexible. The reason they're not being used for TVs and monitors yet is their lifetimes are too short.