testCMS

##Some header stuff updated: 8/6/17 11:07 Just some plain text. new para?? 1. one 2. two 3. three * bullet a * bullet b * bullet c Here is a [LINK](http://google.co.uk) **Reynolds Number** Osborne Reynolds was a late 19th century scientist who studied the flow of fluid within pipes looking at the conditions when flow transitioned between laminar and turbulent regimes. $$ {Re} = {\rho V L} \over {\mu} $$ where: \$\rho\$ is the fluid density \$V\$ is the fluid velocity with respect to the object \$L\$ is a characteristic length \$\mu\$ is the dynamic viscosity of the fluid Re is the ratio between inertial and viscous forces within a moving fluid. It ca be a useful tool in determining if a flow (within a pipe, say) will be laminar (smooth and steady) or turbulent (chaotic). It is also useful when scaling fluid dynamic problems. Very roughly, low Re (\$<10^3\$) indicates that laminar flow will prevail whereas higher Re (\$>10^4\$) tends to indicate turbulent flow. **Fly Tying Info** __Red Zebra Midge__ Seems to be pretty attractive to Grayling. Hook: Partridge, Grub Straight Eye barbless #16 (K4AY-SE). Head: Hends gold tungsten TPG/2 Body: Red UTC 70 Rib: fine gold wire. Use thread to build up a body tapering from head to tail. Evenly spaced rib windings. __F-Fly__ Basically the same as the On-Stream Guide version. Hook: Tiemco 103BL (#15) Thread: Lt Cahill UNI 6/0 (also red UTC 70) Body: Peacock Herl (2 strands) Wing: 2 dark Polish CDC Tie in herl and bring forward to about 1/3 from eye. Tie in CDC slopin back over body to bend of hook. Finish with a thread head. __Black Magic Nymph__ Hook: Hanak H450BL Jig #14 Thread: Black (Uni ^/0) or Red UTC 70 Head 2.3mm Rainbow bead Tail: few sttrnds of Dark CDC Body: Black Hemingway's Peacock dubbing Hackle: 2/3 turns of Dark CDC caught in by the tip __Beatle (my variation) Hook: Hanak H530BL pupa & allround #12 Body: Black Hemingway's Peackock dubbing. 3mm strip of black foam. Hackle: Grizzle Tie in foam at tail (could use yellow - for visibility- coloured brown on underside). Make thickish dubbing body up to 1/3 from eye. Pull foam over top of dubbing, tie in and trim. Form hackle around here, tie in and form head from therd. END

The Hawker Tempest V. One of the great WWII fighter-bombers. Powered by a 2400hp (1790kW) Napier Sabre II engine it was capable of around 430mph (690 km/h) in level flight at around 18,000ft (5,500 m) and was limited to 540mph (870 km/h), due to compressibility effects, in a dive.

PROBLEM - Black body radiation

Any 'body' absorbed and emits radiation (a central heating 'radiator' does this as you can feel - so do you. If we leave something in the sun it warms up as it absorbs infra-red radiation ...). As things get hotter they emit radiation at higher and higher frequencies - first at infra-red, then they may glow red, then orange ... white hot ... into the ultra-violet ... and os on. In fact they don't just emit with a single frequency but over a whole spectrum. Black Body radiation is radiation from a theoretical perfect emitter. This can be closely approximated by a cavity (box) with a very black lining and only a small hole were the escaping radiation can be observed.

There are 2 experimental 'laws' that describe the from of the radiation:

Wien's Displacement Law

$$ \lambda_{max} = {2.898 \times 10^{-3}} over {T} $$

Which describes the wavelength (at least at higher frequencies) at which maximum radiation emission occurs

and Stefan's Law

$$ P = \sigma T^4 $$

Which describes the power output at a given temperature

Classical physics analysed this by thinking about energy as waves within the box, bouncing around and exchanging energy with the walls of the cavity.

This was done by Lord Rayleigh and (independently) by Sir James Jeans to give the Rayleigh0Jeans Law. Unfortunately this doesn't actually match observations and, at short wavelengths, predicts infinite radiation intensity - Bugger!

1900 -Planck

All this was resolved in 1900 by a German physicist going by the rather wonderful name of Max Karl Ernst Ludwig Planck (let's have no more jokes about being as thick as a plank please!).

Building on the ideas of Boltzman's statistical approach to thermodynamics, Planck postulated that energy could only be emitted or observed in distinct, discrete 'quantised' packets (see where this is going yet?) now described by the equation:
$$ E=h\nu$$
Where $E$ is the energy, $\nu$ is the frequency and $h$ is Planck's constant (which very small: $6.62607004 × 10^{-34} m^{2} kg s^{-1}$)

Apparently he really hated the idea - but it worked and he was awarded the 1918 Nobel prize for Physics - which can't be bad can it?

Hello world! Welcome to the madhouse

GreyMamba

Thinking Allowed … (under construction)

Thinking Allowed … (under construction)

Thinking Allowed … (under construction)