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Thursday, May 26, 2022

speed of delivery - the doppler test !!

"Über das farbige Licht der Doppelsterne und einiger anderer Gestirne des Himmels” .. .. .. can you decipher what this is about ??

On the coloured light of the binary stars and some other stars of the heavens -  a treatise by Doppler (1842) in which he postulated his principle that the observed frequency changes if either the source or the observer is moving, which later was termed  the Doppler effect.

At MV Diabetics – every time, I go for full check-up, besides blood tests, there are checks on retina, leg, kidney and more .. .. one of them is Doppler test ! - Doppler ultrasound is a noninvasive test  used to estimate the blood flow through the  blood vessels by bouncing high-frequency sound waves (ultrasound) off circulating red blood cells. A Doppler ultrasound may help diagnose many conditions, including: blood clots, poor functioning of valves in leg veins, heart valve defects, blocked artery, decreased blood circulation in legs, bulging arteries and more.

IPL is drawing to a close and what a engrossing match it was between Lucknow Super Giants and Royal Challengers Bangalore. RCB had a big surge with a partnersnip of 92 off a mere  41 balls – but it could well have been 0 off 2 balls! – LSG was without luck !

It was - 13.3 – Ravi Bishnoi was bowling a good spell, Dinesh Karthik who had just come, was sort of struggling to read him.  A wrong’un turning so much, left DK bamboozled – while everyone thought it was clear LBW, Umpire had different view !  - Hardik Pandya reviewed,  it was marginally pitching outside (Umpire’s call) but clipped leg – had it been given out by Umpire earlier, he would have stayed with the decision but Karthik getting a reprieve went on to score more !

Balls later 18.1 – Chameera to DK- it was reverse. The ball struck the pads, DK was given out and he went to review.  He had shuffled across expecting a wide yorker – Chameera bowled straight and hit the boot on the full.  But this time, Ultra edge scored scratches though to the naked eye, there appeared some gap between bat and pad.  

LSG had an organized chase but close to finish line came back Harshal Patel who had given just 8 off 2 – started off badly with two wides, one of which went for four too, beating DK.  But came back strongly with mix of short and slower ones, frustrating Stoinis, who hit correctly and powerfully but straight to deep throat – Patidar standing there.   The man can do nothing wrong, destined to perform.   Rajat Patidar, a Royal Challengers regular was left out this year, went unsold but came in mid-season as cover for an injury to Luvnith Sisodia – today he scored a sensational unbeaten 112 off 54 to propel the team into the second Qualifier.  He had his share of luck too -   dropped in the 16th over, he scored 40 off 14 balls.  

Amid all the carnage, Super Giants' Mohsin Khan and Royal Challengers' Harshal Patel returned identical and remarkable figures of 4-0-25-1.  IPL stirs controversies every now and then – this time it was technology.  Ultra-Edge have picked edges that didn't exist and vice-versa while on one instance.  It was shambolic when CSK played MI when there was no DRS available due to a power failure. Then came this bloomer – when in the Qualifier between Gujarat Titans and Rajasthan Royals, speedometer showed R Ashwin bowling a delivery at 131.6 kph.  It was the eight over of  the Titans innings, Ashwin bowled a ball at his normal speed, which must have been around the 85-95 kph-mark. But surprisingly, the speedometer showed the ball to be bowled at over 130 kph, which Matthew Wade glided away for a single. Sure enough, users on Twitter were quick to spot the glaring error and expressed their opinions on the gaffe. This wasn't the first time at the speedometer messed up. During the match between Delhi Capitals and Mumbai Indians, the piece of technology reported a delivery from Kuldeep Yadav to be at 116 kph. Kuldeep has often varied his pace and added speed to his deliveries, but the maximum he has stretched it is in the early 100s.

Measuring the velocity of the ball through Radar Guns or Speed Guns is like measuring the speed of the moving car. This technique was discovered in 1947 by "John Baker".  Speed gun works on the principle of Doppler Effect. This Speed Gun has a receiver and a transmitter. The Speed Gun is placed on a high pillar near the Sight screen, from which Speed Gun sends radio wave in the direction of the pitch and calculates the speed of any object on the pitch.  The gun basically captures the speed by measuring the speed of the ball without error.  As the ball passes the radar gun, the speed is recorded and speed details are flashed on screen, not only in Cricket but also in Tennis. 

Technology at best is technology and can be interpreted differently.  There are some different correlations on how the delivery could be faster than it is.  Batsman are brought up on a diet of right-arm-over bowling that is released from high-on the same area, ball after ball after ball. Remove that familiarity, and the feeling of speed goes up. In the Caribbean in 2019, TV showed Jasprit Bumrah's release point was half a metre closer to the batter than Kemar Roach's. This gave Bumrah the effect of bowling 3.7mph faster than the speed gun was showing.  To read it differently, if every other bowler bowls from 22 yards, Bumrah release makes it only   21.5.

Christian Andreas Doppler (1803- 1853)  was an Austrian mathematician and physicist. He is celebrated for his principle – known as the Doppler effect – that the observed frequency of a wave depends on the relative speed of the source and the observer. He used this concept to explain the colour of binary stars. At the age of 38, Doppler gave a lecture to the Royal Bohemian Society of Sciences and subsequently published his most notable work, Über das farbige Licht der Doppelsterne und einiger anderer Gestirne des Himmels ("On the coloured light of the binary stars and some other stars of the heavens").  The Doppler effect is the change in frequency of a wave in relation to an observer who is moving relative to the wave source.  A common example of Doppler shift is the change of pitch heard when a vehicle sounding a horn approaches and recedes from an observer. Compared to the emitted frequency, the received frequency is higher during the approach, identical at the instant of passing by, and lower during the recession.

Interesting ! – confusing !!


With regards – S. Sampathkumar
26th May 2022. 

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