Is the world getting better, or worse?

A few days ago, on Facebook, the following graphic caught my eye.

From http://www.businessinsider.com/the-world-is-becoming-a-better-place-2014-10#ixzz3HumR3IGy

Average life expectancy in England in 1843 was only 40 years. According to How the Mid-Victorians Worked, Ate and Died., those who survived being born, accidents & infections in the first five years of life lived to a ripe old age, despite no modern drugs or other medical technology.

This suggests that mortality between the ages of zero to five was ~50% back then. Yikes.

Click the link in the caption to see other ways in which the world has got better.

It's not Friday the 13th, but... Part 2

In It's not Friday the 13th, but..., I had a picture of my then new Solar PV installation.

1.35kWp Solar PV using Kyocera 135W panels + 2kWp Solar thermal using 100W Thermomax tubes.

As the Solar thermal tubes were no longer heating the hot water much (they were installed in 1991), I decided to upgrade my system. It now looks like this...

3.5kWp Solar PV, using Hyundai 250W panels.

Of the twenty 100W Thermomax evacuated heat-pipe solar collector tubes, only one still worked.

The limescale-coated bulb at the bottom is very hot!

Hot water is now heated by the immersion heater in the tank in the airing cupboard, using spare electricity that's been generated but not used. This is controlled by a gizmo called an immerSUN. See below. The immerSUN is at top left. The inverter is at bottom right.

The current-sensing transformer is the black thing around the red wire, sitting on the black fuse.

The water from the hot tap is now hot enough to make instant coffee!

As the company that installed the upgrade had previously only installed systems to properties previous without Solar PV, they thought that I would receive the current Feed-In Tariff rate, which is 16.56p/kWh, including 50% export Tariff. This is much lower than the Feed-In Tariff rate that I was receiving for my 1.35kWp installation, which was 47p/kWh, including 50% export Tariff. They suggested that I phone ScottishPower (my energy supplier) for clarification.

The good news is that I will receive 47p/kWh for 1.35kW and 16.56p/kWh for the additional 2.15kW, making a net Feed-In Tariff of 28.3p/kWh, including 50% export Tariff. That's 71% more than I thought I'd get.

Based on PVGIS data (postcode-dependent), the system should generate 3,210kWh/annum. That's £908/annum in Tariffs + ~£240/annum in saved electricity consumption + ~£50/annum in saved gas consumption = ~£1,198/annum. The system cost £7,700 including VAT, so ROI is 15.6%. Feed-In Tariffs increase by ~5%/annum and energy prices increase by ~14%/annum, so the system should pay for itself in ~5 years.

Organic is best!

I'm not talking about vegetables, though.

The above display panel is 4mm thick. Wow! There are 0.3mm thick panels in development. Double-wow!

OLEDs can also be used for lighting.

For more information, see OLED-Info. When I first heard about organic LED's, I thought "They'll have too short a life to catch on." Oh, whoops!

EDIT: I've just spotted Organic Light Emitting Transistors (OLETs). Oh, Myyy!

Trilayer OLET device and chemical structure

What to do if subjected to a Denial of Service attack.

A couple of weeks ago, I lost internet access for about 30 mins due to a Denial of Service (DoS) attack.

I feel honoured that I've annoyed someone on the internet so much that they spent time and effort DoS attacking me!

Brute-force attacks from individuals are difficult, as my downlink speed is much faster than most people's uplink speed. To mount an effective brute-force attack requires multiple computers infected with a trojan. This is known as a Distributed Denial of Service (DDoS) attack and requires a lot of computer knowledge.

A much simpler approach is the SYN flood attack. I believe that I was subjected to one of these, as on rebooting, I temporarily had internet access but lost it after a few seconds when all of the available connections on my pooter became "half-open".

To defeat such an attack is simple. All that you have to do is harden the TCP/IP stack. See also http://msdn.microsoft.com/en-us/library/aa302363.aspx and http://www.pctools.com/guides/registry/detail/1237.

Fun with LEDs.

Warning! Techy, nerdy stuff.

Pretty!

When I were a lad (!), I remember the invention of the Light-Emitting Diode (LED). They were originally made out of Gallium (Ga) & Arsenic (As) instead of Germanium (Ge and now I'm really showing my age!) and Silicon (Si). Gallium & Arsenic are used to "dope" Silicon to form P & N regions respectively (Gallium has 3 electrons in its outer shell & Arsenic has 5. Germanium & Silicon have 4).

GaAs red LEDs weren't very bright. By adding Aluminium, Indium, Phosphorus, Nitrogen etc, new colours & higher-efficiency old colours were invented. Orange. Yellow. Green. Brighter green. Even brighter green. Really bright green. I thought that blue LEDs would never be invented. Wrong!

Nowadays, OLEDs are so efficient that they can be used for lighting and they are more efficient and longer-lasting than CFLs. I thought that OLEDs would never catch on. Wrong! The superb display on my Samsung phone uses AMOLED technology. But anyway...

What I found interesting about GaAs red LEDs was their I-V characteristic.

Pretty techy!

Over a wide range of currents, the voltage is ~1.75V. The steep slope means that the dynamic resistance (δV/δI) is very low. I thought to myself "Hmmm, voltage regulator!" Zener diodes are usually used as voltage regulators, but they are very noisy. A forward-biased P/N junction produces less thermal noise than a resistor with the same value as the dynamic resistance of the P/N junction. As the voltage (~1.75V) is temperature-dependent (-2mV/ºC), the relative temperature variation of a red GaAs LED is less than that of a Silicon diode (~0.7V when biased on).

I used two "strings" of red GaAs LEDs as an ultra-low-noise voltage limiter in a high-power oscillator using LDMOS MOSFETs that had just been invented by Mullard (which later became Philips). It produced 1W (+30dBm) over a frequency range of 30 to 88MHz and had a Carrier to Noise Ratio (C/N) of >190dBc/Hz @10% frequency offset. Typical RF Signal Generators of that era had a C/N of ~145dBc/Hz at that offset.

I hope that you've enjoyed this little tour around my brain!

Use and abuse of technology and energy.

Take a look at the picture below.

Samsung Galaxy S vs iPhone 4

Using technology and energy: Oil, ores, minerals and sand are turned into plastics, metals, ceramics and glasses. The latter cost and are worth more than the former. Using more technology and energy: Plastics, metals, ceramics and glasses are turned into smart-phones, computers, TV sets, cars, planes, musical instruments, w.h.y. The latter cost and are worth more than the former. Creating gizmos creates wealth and increases value.

Take a look at the picture below (hat-tip to Beth Mazur).

You know who is really leaning in? Little Debbie. We have enough crap to eat. Dial it back a little.

Using technology and energy: Produce are turned into crap-in-a-bag/box/bottle (CIAB). The latter cost more than the former but are worth less, as nutritional value has been reduced. Creating CIAB creates wealth but decreases value.

I would like there to be more production of gizmos and less production of CIAB.