Saturday, 5 October 2024

இந்து மகா சமுத்திரம் என்ற பெயர் காரணம்

என் முகநூல் பக்கத்தில் கடந்த 2022 ஆம் ஆண்டு அக்டோபர் மாதம் 5 ஆம் தேதி நான் இட்ட பதிவின் மறு பதிவு இது. 



அரேபியர் இந்த பகுதி பெருங்கடலுக்கு வைத்த பெயர் இது. பாண்டியர், சோழர்கள், சேரர்கள் இந்த பகுதி கடலை அப்படி ஒரு கட்டுபாட்டில் வைத்து இருந்தார்கள். அவர்கள் இந்துக்கள். அரபி, துருக்கிய ஏன் பல மத்திய ஆசியா, மற்றும் கொரியா, சீன மொழிகளில் நமக்கு ஹிந்த் என்று பெயர். அதில் இருந்து வந்தது ஹிந்துஸ்தான். இந்தியா என்ற பெயர் அதில் இருந்து வந்த இண்டிகா என்ற கிரேக்க சொல்லின் ஆங்கில தழுவல் இந்தியா. உலகில் ஒரு  இனத்தின் மற்றும் நாட்டின் பெயரில் உள்ள ஒரே பெருங்கடல் இந்துமகா சமுத்திரம். பிரெஞ்சு மொழியில் லாண்ட் L'Inde என்று கூறுவார்கள் இந்தியாவை.

சிந்து நதியை வைத்து அவர்கள் ஹிந்த் என்று அழைத்தார்கள். அரபிக் கடலை அரேபியர் இந்துக் கடல் அல்லது bahr alhind بحر الهند என்று அழைப்பர். அரபிக் கடல் என்பது இந்து மஹா கடலின் ஒரு பகுதி. இந்தியாவை அவர்கள் almuhit alhindiu المحيط الهندي என்று அழைத்தார்கள்.

இந்து மகா சமுத்திரம் என்ற இன்றைய பெயர் (பொது வருடம் CE) 1515 ஆம் வருடம் லத்தின் மொழியில் Oceanus Orientalis Indicus ("Indian Eastern Ocean") என்று கொலம்பஸ்/ வாஸ்கோடகாமா காலத்தில் இந்த கடலை ஐரோப்பியர் அழைத்தனர், அதன் ஆங்கில  மொழி பெயர்ப்பு தான் இந்தியன் ஓசியன் என்ற இன்றைய சொற் பதம்.

சமஸ்கிரத மொழியில் இந்த கடலுக்கு பெயர் இரத்நாகரா Ratnakara. இலங்கையில் உள்ள ஒரு ஊர் பெயர் இரத்னாபுர. இரத்னாகரா என்றால் இரத்தினங்கள் என்று பெயர்.  இன்றும் இலங்கை இரத்னாபுர பகுதியில் இரத்தினங்கள்  கிடைக்கும்.  இலங்கையில்  பலர் வைத்துக்கொள்ளும் இணை பெயர் இரத்னாகரா.

Tuesday, 27 February 2024

The Indian Astronauts

The Bharatiya Prime Minister Narendra Damodar Das

 

Modi inaugurates three space projects startup. Ganganyan orbital mission will be the first. 

1. Indian Space Station 
2. Indian landing on the moon
3. Ganganyan orbital mission.

Indian Astronauts will be called ' Vyomanauts'

A. Vyomanaut 1. GROUP CAPTAIN PRASANT NAIR

B. Vyomanaut 2. GROUP CAPTAIN AJIT KRISHNAN

C. Vyomanaut 3. GROUP CAPTAIN ANGAD PRATAP

D. Vyomanaut 4. WING COMMANDER SHUBANSHU SHUKLA

They will be going to space by 2025 end from Bharat. 

Monday, 26 February 2024

NEUTRINOS - What are they?

 


Exploring Neutrinos: A Fascinating Journey Through Science

Introduction

The mysterious world of neutrinos has intrigued scientists for decades. This blog aims to bring together the exciting discoveries and research about these elusive particles, drawing from various scientific publications, research institutions and government laboratories. All the information shared here is publicly accessible and offers a glimpse into the fascinating study of neutrinos.

The Discovery

Back in 1956, scientists made a groundbreaking discovery by experimentally identifying the neutrino. In the Standard Model of Particle Physics, the neutrino is a particle that stands out due to its tiny size, neutral charge and elusive nature. Neutrinos are the most abundant particles with mass in the universe. They are produced in processes like nuclear fusion in stars and radioactive decay in reactors. Even everyday items like bananas emit neutrinos because of the radioactive potassium in them. Despite their abundance, neutrinos rarely interact with matter. Trillions of neutrinos from the sun pass through our bodies every second, yet we don’t feel a thing.

Neutrinos were first theorised in 1930, but it took 26 years to confirm their existence experimentally. Today, scientists are keen to understand more about these particles, including their mass, how they interact with matter and whether they might be their own antiparticles. Some theories even suggest that neutrinos could help explain why the universe is made mostly of matter rather than antimatter after the Big Bang.

Neutrinos: The Ghost Particles

Neutrinos are part of a group of elementary particles called leptons and are often called "ghost particles" because of their ability to pass through matter almost without interaction. They are fundamental components of the universe, just like electrons, muons and taus. Wolfgang Pauli first proposed the existence of neutrinos in 1930 to explain energy discrepancies in radioactive beta decay, but it wasn't until 1956 that they were detected. The term "neutrino" was coined by Enrico Fermi in 1932 and later popularised by Edoardo Amaldi.

In 1942, Wang Ganchang suggested using beta capture for neutrino detection, leading to their eventual discovery by Clyde Cowan, Frederick Reines and others in 1956. This discovery earned them the Nobel Prize in 1995.

Properties of Neutrinos

Neutrinos are electrically neutral and have a very small mass compared to other subatomic particles like electrons or quarks. They interact mainly through the weak nuclear force, responsible for processes like beta decay and occasionally through gravity. Due to their rare interactions, detecting neutrinos is extremely challenging. Neutrinos come in three types—electron neutrinos, muon neutrinos and tau neutrinos—each associated with specific leptons. These types can change from one to another as neutrinos travel through space, indicating that they have mass.

How We Detect Neutrinos

Detecting neutrinos requires highly sensitive instruments due to their minimal interaction with matter. Various methods are used, including Cherenkov Radiation, Neutrino Capture and Inverse Beta Decay. Cherenkov Radiation is similar to a sonic boom but occurs when a particle exceeds the speed of light in a medium like heavy water (D2O). This phenomenon helps indicate the presence of neutrinos and can also suggest superluminal motion in certain theoretical contexts.

Cosmic Importance of Neutrinos

Neutrinos play a crucial role in many astrophysical processes. They are produced in large quantities during nuclear fusion in stars, supernovae and other high-energy cosmic events. Neutrinos from the sun help us understand solar fusion, while those from distant sources provide insights into the universe's most energetic phenomena, such as active galactic nuclei and gamma-ray bursts.

Unanswered Questions

Despite significant progress in neutrino research, many mysteries remain. The exact masses of neutrinos are still unknown, with experiments only providing upper limits. Neutrino oscillation shows they have mass, but precise measurements are elusive. Additionally, the imbalance between matter and antimatter in the universe suggests possible differences between neutrinos and their antimatter counterparts—antineutrinos. This is an area of active research in particle physics.

Conclusion

Neutrinos are among the most fascinating and mysterious particles in the Standard Model of particle physics. Studying them not only enhances our understanding of fundamental physics but also sheds light on the deeper workings of the universe, from cosmic dynamics to the essence of matter itself. As research continues, we can look forward to uncovering more secrets about these ghostly particles that play such a significant role in our universe.

 #Neutrinos #PhysicsForEveryone #ElementaryParticles #AstrophysicsBasics #ScienceExplained #TheInvisibleUniverse #UnderstandingNeutrinos #CuriosityAndWonder #ScienceStorytelling #ThePoetryOfPhysics #ExploringTheUnseen #DhinakarRajaram #ScienceBlogIndia #NeutrinosWhatAreThey

 

Sunday, 14 March 2021

Difference between an Air-Conditioner and an Air-Cooler

I am seeing lots of Air Coolers advertisements for many years. Many outlets are also selling them without giving an important reason. They're actually hiding those for their sales. 

 

Air Coolers are humidifiers technically. They induce humidity in dry areas like those places in interior like Salem, Vellore, Nagpur, Delhi etc. Where room AC won't help while a central AC can help. Interior areas have very less humidity, so they’ll feel hot. When we induce humidity, we feel a cooling effect as humidity goes up.

 

Whereas in coastal areas, air conditioners will help and work as they dehumidify the air. Because the coastal areas have lots of humidity, it needs to be reduced. When reduced, we feel a cooling effect as AC will also suck moisture on your skin. 

 

While a central AC is a different animal. It is a hybrid of Air cooler and an air-conditioner. 

 

One thing, if you have low or high blood pressure, have cardiac issues, please be careful when you come out of an AC room. Temperature difference between inside and outside during peak summer will be drastic. It will take time for your body to adjust. That gap may kill you as changes/ shift will be sudden & extreme and body will try to adjust by trying to rush blood on emergency to skin and brain. But it can't do that instantly. So heart is put onto maximum strain and it may lead to cardiac arrest or even a brain stroke. 

 

In 2000/2001 I experienced that physically. I was shopping in Spencer's. Mall was 22° C and immediate outside temperature was 43° C. A difference of almost 21° C, my body struggled to adjust and I was about to get knocked down unconscious. 

 

Especially people with comorbidities, aged should be careful in an air-conditioned environment. Same effect may be felt in reverse during winters.

 

The Air Conditioners maintain an ambient temperature of 20 to 24° C. During winters, many areas experience colder temperatures, the room temperature will be pretty warm and outside temperature will be cold. This difference in temperature may also induce similar health issues I marked above.   

 

In French the Air Conditioner is called CLIMATISEUR & for Air Coolers REFROIDISSEUR D’AIR which says their original intended usage and purpose.

Monday, 11 May 2020

Bangladesh Railway

 

Bridges, Borders, and the Forgotten Rails: The India–Bangladesh Frontier Revisited

Prelude: The Divided Tracks of the East

 

The story of Bengal’s railways is, in many ways, a tale of belonging and bereavement. Few other regions in the subcontinent witnessed such an abrupt severing of iron and emotion. Once, the rhythmic pulse of trains traversed unbroken through these lands, from the bustling terminus of Calcutta to the distant halts of Chittagong and Assam. Then came 1947 — the year of Partition — and the rhythm faltered. What was once a seamless network became a cartographer’s casualty.

In the decades that followed, border stations turned into ghostly outposts. Platforms that had once greeted travellers and traders were left to the mercy of vines, silence, and nostalgia. Yet, the steel never forgot its purpose. Even when dormant, it remembered — waiting patiently for a time when connections might once again outpace divisions.


Rails Between Realms: The Haldibari–Chilahati Legacy

Amongst the many dismembered lines of the eastern frontier, the Haldibari (India)–Chilahati (Bangladesh) corridor remains emblematic of both interruption and endurance. Once part of the grand Siliguri–Calcutta main line, these stations lay on the venerable broad gauge track that stitched together the northern plains with the port city of Calcutta.

At Partition, Haldibari fell within India’s Cooch Behar district, while Chilahati drifted into East Pakistan. Still, the trains ran — a fragile continuity — until the Indo-Pak War of 1965, when all cross-border railway movement in the eastern corridor came to an abrupt halt.

The distance between Haldibari and the international border is a mere 4.5 kilometres, while Chilahati lies 7.5 kilometres from the zero point on the Bangladeshi side. By the early 2020s, work on the Indian side had been nearly completed — more than 95 per cent of track-laying done — with progress on the Bangladeshi side dictating the pace of completion. The restoration of this link promises more than just connectivity; it represents the revival of a memory long buried under political dust.


Metre-Gauge Memories: Bengal’s Narrower Arteries

In earlier decades, the Bengal frontier was laced with metre-gauge lines that carried not only freight but also the pulse of small-town life. The Radhikapur–Biral–Parbatipur and Changrabandha–Burimari branches once linked West Bengal to northern Bangladesh — fragments of the Lalmonirhat–Malbazar line, developed in the twilight years of the nineteenth century by the Bengal Dooars Railway.

When Partition came, the Indian side terminated at Changrabandha and the Pakistani side at Burimari. Today, the Radhikapur–Biral–Parbatipur section has been upgraded to broad gauge, while Changrabandha–Burimari remains a name whispered among the abandoned corridors of railway lore.


Lalmonirhat and the Lost Corridors of Connection

By the turn of the nineteenth century, Lalmonirhat had emerged as a railway citadel in north Bengal — a vital junction from which iron veins stretched to Assam and beyond. Two metre-gauge corridors once linked this region with Cooch Behar:

  • Lalmanirhat–Mogalhat–Dharla River Bridge–Gitaldaha, and

  • Bamanhat–Golokganj, both facilitating seamless travel from Bengal to Assam.

The GitaldahaMogalhat crossing, divided by the Dharla River, is today but a spectral reminder. Mogalhat lies on the Bangladeshi side in Lalmonirhat District, while Gitaldaha — now defunct — sits quietly in India’s Cooch Behar. A new Gitaldaha station was later built further north, feeding into the Bamanhat line.

Before independence, a single 1,000 mm wide metre-gauge artery connected Fakiragram (Assam) to Katihar (Bihar) via Radhikapur, Biral, Parbatipur, Kaunia, Tista, Gitaldaha, Bamanhat, and Golokganj. This line, operated by the Eastern Bengal Railway, was the principal route to Assam’s Amingaon Port from Semaria Ghat in Bihar — a lifeline of trade and travel that spanned the heart of the subcontinent.


Assam’s Gateway Through Bengal

Until the 1960s, a modest but important line linked Cooch Behar to Dhubri (Assam) via Golokganj, known as the Assam Line Railway Service. Remarkably, even after Partition, this route continued through East Pakistan between Bamanhat and Golokganj, embodying a rare continuity amid division.

The Sonahat crossing, another forgotten rail transit point, once connected Golokganj to Kurigram by metre gauge. Over time, floods, neglect, and shifting political sands erased this link from the living map.

Notably, the Assam Mail — immortalised in the 1943 Bradshaw’s India Time Table — plied this network, running from Katihar to Tinsukia Junction, with a slip pair joining from Calcutta at Parbatipur. In those days, the railway was the subcontinent’s bloodstream: from Awadh to Assam, from Chittagong to Tinsukia, the iron roads of Eastern Bengal carried a civilisation in motion.


Mahisasan–Shahbajpur: The Silent Frontier of the North-East

Further east, the Mahisasan–Shahbajpur (Latu) link between Assam’s Karimganj district and Bangladesh’s Sylhet region once served as a critical metre-gauge corridor. The line connected Mahisasan to Karimganj, eleven kilometres apart, and was operational until the 1965 war severed ties.

In the 1950s, international trains ran between Kulaura (East Pakistan) and Badarpur (India) on this very gauge, with rolling stock belonging to the Eastern Bengal Railway. Today, the line lies in disuse, its sleepers overtaken by weeds — a once-bustling gateway now a border relic.


New Corridors of Hope: The Tripura Connection

If the older links are memories, Tripura is the promise of renewal. Two new cross-border connections are poised to transform the North-East’s railway geography:

  • Agartala (India) – Gangasagar (Bangladesh), and

  • Belonia (India) – Feni (Bangladesh).

The Agartala–Gangasagar line, spanning 15.6 kilometres, includes 10.6 km on the Indian side (up to Nischintapur) and 5.46 km connecting Nischintapur to Agartala station. Nischintapur will host the region’s first trans-shipment yard, where passengers and goods from Bangladesh will interchange — a symbolic and logistical bridge between the two nations.

Once dual-gauging is completed across Bangladesh’s eastern corridor, a direct service between Agartala and Kolkata is envisaged — running via Tangail, the Jamuna Rail Bridge, and the Hardinge Bridge — effectively reuniting the North-East with the eastern seaboard.

By early 2021, work on the Indian side was well underway, the hum of welding torches and concrete mixers replacing the long silence of inactivity.


Over the Jamuna: From Ferry to Bridge

Before the advent of the Bangabandhu Bridge (1996–97), the people of Bangladesh’s central regions depended on rail ferries to traverse the mighty Jamuna (Brahmaputra) River. These ferries were the arteries of connection between the western and eastern halves of the country.

Two major ferry crossings once operated — between Sirajganj Ghat and Jogannathganj Ghat, and between Bahadurabad Ghat and Tistamukh Ghat. The western banks were served by broad gauge lines from Ishurdi, linking eventually to Calcutta, while the eastern banks relied on the metre-gauge system.

The completion of the 4.8-kilometre Bangabandhu Bridge fundamentally altered the nation’s communications landscape. By 2010, the ferry systems at Bahadurabad–Balashi and Jogannathganj–Sirajganj had been phased out, the former succumbing to riverine shoals and siltation. The river’s old channel — tracing its way from the Jamuna’s divergence to the Shitalakshya’s mouth — remains a reminder of the days when ferries were as integral to the railway as the trains themselves.


The Shifting Lines of the East

In the years following the bridge’s completion, a new metre-gauge line was laid from Bangabandhu East station to Taraknandi in 2008, replacing the now-abandoned Taraknandi–Jogannathganj Ghat line on the Jamuna’s banks. This transition symbolised the region’s evolution from a river-dependent system to an integrated rail corridor, uniting the once-distant halves of Bangladesh through engineering vision.

Between Akhaura and Kulaura, the now-defunct Shaistaganj–Habiganj and Kulaura–Latu branches once hummed with life. Today, they rest in quiet disuse, reminders of an era when railways traced every contour of the land, binding together the diverse destinies of Bengal, Assam, and Sylhet.


Epilogue: The Iron Memory

From Haldibari’s sidings to Agartala’s new yard, the story of these lines is not merely one of transport — it is the saga of resilience and remembrance. Borders may have altered geographies, but the railway — that steadfast servant of civilisation — continues to seek reunion.

Every whistle that pierces the silence of the border carries within it the echo of the past — of friendships rekindled, economies revived, and histories reconnected. Steel may age, bridges may corrode, but the railway’s dream remains immutable: to link hearts as much as it links lands.


Coda: The Pulse Beneath the Rust

Across the frontierlands of Bengal and Assam, where rivers shift and rails remember, the old alignments whisper of a past that refuses to fade. Each bridge rebuilt and each sleeper relaid is not merely an act of engineering but a gesture of reconciliation — an attempt to restore continuity where history once drew a line.

Steel may corrode, maps may change, yet the rhythm of the railway endures — steadfast, sonorous, and forgiving. Beneath the rust lies a pulse that still beats for unity.


Glossary

  • Broad Gauge (BG): Railway track spacing of 1,676 mm, the predominant standard in India.

  • Metre Gauge (MG): Narrower track gauge of 1,000 mm, once common across Bengal and Assam before conversion to broad gauge.

  • Eastern Bengal Railway: A pre-Independence railway company operating routes across undivided Bengal and Assam, many of which now traverse modern Bangladesh.

  • Partition (1947): The division of British India into India and Pakistan, which severed many through railway routes in the East.

  • Transit Point: A designated cross-border junction permitting customs and railway interchange between two national systems.

  • Hardinge Bridge: A major railway bridge over the Padma River in Bangladesh, built during British rule (1915).

  • Bangabandhu Bridge: The 4.8-km bridge over the Jamuna River (1996–97) linking western and eastern Bangladesh.

  • Bradshaw: The authoritative British-era railway timetable and guidebook of Indian train services.

  • Fakiragram / Amingaon Port: Historic railway termini in Assam linked by the Eastern Bengal Railway network prior to 1947.


Copyright Notice

© 2020–2026 Dhinakar Rajaram. All rights reserved.
This article, including its text, phrasing, and historical analysis, is the author’s original work. Reproduction, distribution, or adaptation in any form without explicit written consent from the author is strictly prohibited. Quotations or references may be made with proper attribution and citation of the source.


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#IndianRailways #BangladeshRailway #EasternBengalRailway #PartitionHistory #RailwayHeritage #HaldibariChilahati #CrossBorderRails #BengalRails #ForgottenFrontiers #DhinakarRajaram

 Bridges, Borders & Forgotten Rails — tracing the lost lines between India and Bangladesh. 🚂
#RailwayHistory #BengalRails #DhinakarRajaram




Thursday, 30 April 2020

108 years old Elephant Gate bridge pulled down!






108 years old Elephant Gate Bridge has been pulled. For past few years traffic was stopped permanently on this bridge and supporting steel rods were erected to hold the bridge as it has gone old and rickety. Secondly, the bridge was 50 metres in length. Which created a chicken neck like situation. Where tracks get squeezed allowing only 6 tracks under it. Before and after the bridge tracks are broad. Resulting in unduly holdups. A train arrives on time or well ahead to perambur or basin bridge, but holdup for 20 to 30 minutes due to this bridge as only 6 trains - 3 up and 3 down can pass any given time. There by affecting the train movements to and fro from Central. Now railways will build a steel bridge of 150 metres, there by giving room to atleast 10 tracks and holdups will be reduced as trains can enter and exist easily. Plans also there to shift west bound trains to Salt Cotaurs as 4th terminal. 

Sunday, 26 April 2020

Is it Day or Night?



Why sky appears blue even in night? What are those two stars above that water tank?   Irrespective of day or night, our atmosphere scatters blue colour. This was found by Sir. Chandrasekhara Venkata Raman, FRS or Sir. C.V. Raman! He was the recipient of the Nobel Prize for Physics in 1930 for the discovery that when light traverses a transparent material, some of the light that is deflected changes in wavelength. This phenomenon is now called Raman scattering and is the result of the Raman effect.  Raman scattering or the Raman effect is the inelastic scattering of a photon. It was discovered by C. V. Raman and K. S. Krishnan in liquids, and by G. Landsberg and L. I. Mandelstam in crystals. The effect had been predicted theoretically by A. Smekal in 1923.  When photons are scattered from an atom or molecule, most photons are elastically scattered (Rayleigh scattering), such that the scattered photons have the same energy (frequency and wavelength) as the incident photons. However, a small fraction of the scattered photons (approximately 1 in 10 million) are scattered by an excitation, with the scattered photons having a frequency different from, and usually lower than, that of the incident photons. In a gas, Raman scattering can occur with a change in energy of a molecule due to a transition . Chemists are concerned primarily with such transitional Raman
 effect.  Those two stars are: binary star system Alpha Centauri AB / Rigil Kent ( 4.39 light years from sun) and Hader / Beta Centauri 525.21 Ly away) to its right is Southern Cross or Crux . above is Libra and to left is Scorpios and Lupus constellations.  If we draw a cross line from between these two stars and draw a line from Acrux or Alpha 1 Crux, both will point to south pole point! There is no specific star pointer for Earth's Southern pole as in North pole where we have Polaris!

Image Settings: F2.8, ISO 100. 30 sec exposure. Taken in 2013.  Camera: Fujifilm Hybrid DSLR.

T.K. Radha — The Kerala Girl Who Walked Princeton

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