PHYSICS MAGAZINE INSTITUTE OF PHYSICS SRI LANKA (IPSL) Unveiling the Secrets of Black Body Radiation pg 02 Max Planck's Revolution: DECEMBER 2023, VOLUME 01, ISSUE 01 W,aldmd; len,s j,ska fi!r.%y uKav,fha Wm; pg 18 mDÓúhg ;¾ckhla úhyels .%yl iy Oqufla;= STORIES Institute of Physics Sri Lanka Vidya Mandiraya 120/10, Wijerama Mawatha, Colombo 7 ipsl.lk facebook.com/ipsl.ac.lk ISSN 3021-6710 ISBN 977-302-16-7100-9
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Editorial Board Dr.(Mrs). W W P De Silva Dr. W K I L Wanniarachchi Prof. P K D D P Pitigala Dr. U S Rahubadda Mr. C M Kalansuriya Dr. R Thotagamuge Mr. G H Asoka Mr. D L N Jayathilake Dr. W T M A P K Wanninayake Expert Panel Prof. H H Sumathipala Prof. V P S Perera Prof. P A A Perera Prof. N G S Shantha Gamage Dr. (Ms) H O Wijewardane Prof. D D N B Daya PHYSICS MAGAZINE Y% S ,xld fNd;sl úoHd wdh;kh fNd;sl úoHd iÕrdj INSTITUTE OF PHYSICS SRI LANKA (IPSL) DECEMBER 2023, VOLUME 01, ISSUE 01 Editors Prof. K P S C Jayaratne, Department of Physics, University of Colombo chandanajayaratne@gmail.com Dr. R Chinthaka L De Silva, Materials Technology Section, Industrial Technology Institute chinthakades@yahoo.com Editor-Graphics Dr. D L Weerawarne, Department of Physics, University of Colombo dlweerawarne@gmail.com ISSN 3021-6710 ISBN 977-302-16-7100-9 Institute of Physics Sri Lanka Vidya Mandiraya 120/10, Wijerama Mawatha, Colombo 7 ipsl.lk facebook.com/ipsl.ac.lk
President’s Message Welcome to the IPSL Physics Magazine (Volume 1, Issue 1) of the Institute of Physics Sri Lanka which replaced the earlier “Bhawthika vidya” magazine. Institute of Physics Sri Lanka being the premier body of all physicists in Sri Lanka converging vibrant avenues related to physics appreciates publishing this IPSL Physics Magazine to dynamically mirror the modern approach of disseminating physics knowledge at a larger audience. We always believe that the institute should move beyond boundaries to promote physics knowledge as well as to recognize innovations that could leverage the existing knowledge to match the current underlying requirement. As the world is heading for online acquisition of knowledge at a faster rate these online physics magazine editions are expected to bring significant accomplishments for society not only locally but also internationally. The inspiration that would spell on the reader with evolving stories is expected to nourish their creativity and uplift their groundbreaking thinking where the physics enthusiasts could make significant changes for the coming future. The intention of maintaining this online magazine is also to address the absence of a sustained local standard physics magazine. Daily lives depend heavily on physics which is the cornerstone of the other natural sciences and is essential to understand our modern technological society and the desires of emerging modern cultures. At the heart of physics is the combination of experiment, observation and the analysis of phenomena using mathematical and computational tools. So it is high time to promote physics at large by making use of new techniques and tools to popularize Physics. Best wishes! Dr R Chinthaka L De Silva President-Institute of Physics Sri Lanka
Unlocking the Power of the Stars: The Quest for Fusion Energy December 2023 | Issue 01 01 PHYSICS MAGAZINE Institute of Physics Sri Lanka (IPSL) Are we ready for the next Technological Revolution by Quantum Computing Machines? MAX PLANCK'S REVOLUTION: mDÓúhg ;¾ckhla úhyels .%yl iy Oqufla;= Quantum physics is advancing fields like computing and sensing, yet practical quantum computing remains years away. W,aldmd; len,s j,ska fi!r.%y uKav,fha Wm;" mDÓúh u; Ôjh ìysùu jeks u;fíohg ;=vq § we;s m%Yak .Kkdjlg ms,s;=re fiúh yel' 02 08 Inside stories Small Bodies…. Hazardous or Blessed? Exploring the Enigmatic Small Bodies of Our Solar System: A Journey from Historical Mystique to Modern Science. Delves into the potential of nuclear fusion for sustainable energy, exploring its challenges and advancements. Unraveling the Potential of Electrochromic Devices: Innovative Applications, Energy Efficiency, and the Fusion of Cutting-Edge Technologies for Future Development. fN!;sl úoHd;aulj ;r,hl ÿi%dù;dj foi n,kqfha tys wKq w;r wNHka;r >¾IKh fya;=fjka tu wka;¾ wKql .eàï iy meg,Sï we;s ùfuka isÿjk ixisoaêhla f,ih' fuksid ÿi%dù;dj wêl Wl= ;r,hla ;=, wKq .uka lsÍfï§ idfmalaIj by< Yla;shla jehfõ' 04 18 10 14 Electrochromic Devices (ECD) for Future Development 20 ÿi%dù;dj iy tys Ndú;hka( b;du;au ir<j Institute of Physics Sri Lanka Vidya Mandiraya 120/10, Wijerama Mawatha, Colombo 7 ipsl.lk@gmail.com https://ipsl.lk/ Revolutionizing Medical Diagnostics: The Comprehensive Guide to Positron Emission Tomography (PET) and Its Transformative Impact in Healthcare Imaging. 16 Inspector of Cancer - PET Why it is important for Undergraduates to Begin Research Early 13 Embarking on an Odyssey of Discovery Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01 ISSN 3021-6710 ISBN 977-302-16-7100-9
faced with two enigmatic phenomena that could not be explained using classical physics. umans gazed at the night sky and pondered the vastness of the universe. Meanwhile, scientists were working diligently to unlock its secrets. At the turn of H the 20th century, they were One of these dilemmas was related to the speed of light and its connection to other factors. Albert Michelson and Edward Morley had already established the existence of an inertial observer using the famous Michelson-Morley Experiment in 1887. However, classical physics failed to explain this phenomenon adequately. In 1905, Albert Einstein found a solution to this issue by deriving the special theory of relativity, which, in some ways, disproves classical physics. The second mystery was cantered around "black body radiation." Classical physics was unable to provide a solution for this phenomenon. However, Max Planck proposed a new approach to quantization. It allowed for a non-classical method of solving this puzzle. With this breakthrough, scientists could finally make sense of black-body radiation and understand the spectrum of radiation produced by a black body. Before diving into Planck's work, it is important to understand black body radiation. A blackbody is an object that absorbs all the electromagnetic radiation that falls on it and reflects none of it. When a blackbody is heated, it emits radiation over a wide range of wavelengths. The simplest scenario is an idealized body that is both a perfect emitter and an ideal absorber. A black-body is what this is known as for obvious reasons. The nature of black body radiation depends on its temperature. For example, consider a piece of metal that is heated in a furnace. As the metal heats up, it emits radiation in the form of visible light. Max Planck was a German theoretical physicist who is best known for originating quantum theory, which revolutionized our understanding of atomic and subatomic processes. He received the Nobel Prize in Physics in 1918 for his work in this area, significantly contributing to the foundation of modern physics. “A scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die and a new generation grows up that is familiar with it.” Max Karl Ernst Ludwig Planck (1858 – 1947) MAX PLANCK'S REVOLUTION: UNVEILING THE SECRETS OF BLACK BODY RADIATION Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01
The study of black body radiation has also had significant implications in astrophysics. The radiation emitted by black bodies can be used to study the properties of stars and galaxies, and it has provided important evidence for the Big Bang theory of the universe's origins. Moreover, the principles of black body radiation are also used in material science and engineering, where it is essential for understanding how materials interact with radiation. The concept of emissivity (measures the efficiency of a material's ability to emit radiation) is critical in the design of energy-efficient technologies such as solar panels. Planck's equation for black body radiation (Planck's law), relates the spectral radiance of a black body to its temperature and wavelength can be mathematically expressed as: where B(λ,T) is the spectral radiance of a black body as a function of wavelength λ and temperature T, h denotes Planck's constant, c is the speed of light, and k represents Boltzmann's constant. This equation describes the distribution of Energy emitted by a black body at different wavelengths and temperatures, and it accurately predicts the observed black body spectrum across a wide range of wavelengths. In conclusion, studying black body radiation has been incredibly important in shaping our understanding of the universe. Max Planck's audacious departure from classical physics opened the door to a new realm of knowledge, powerfully influencing our comprehension of the cosmos. As discoveries continue, black body radiation remains fundamental for advancing scientific knowledge. The metal appears dull red at low temperatures, but the colour shifts to orange, yellow, and white as the temperature increases. This colour change is due to the change in the wavelength of the emitted radiation. After Max Planck became a professor at Berlin University, he tried to elucidate Wien's law that his colleague Wilhelm Wien had discovered in 1896. To support the entropy law, he wanted to develop a theoretical foundation for it based on the second law of thermodynamics. The entropy of an ideal oscillator was defined by the "principle of elementary disorder," and he discovered an expression for it that served as the foundation for Wien's law. However, it was later realized that measurements at low frequencies did not agree with Wien's law. He believed that the definition of the oscillator's entropy was the issue. Max Planck proposed a postulate in 1900 that must now be used to solve the problem. He asserts that a black body's oscillator's Energy is quantized and equal (E = ℎ where is a positive integer and ℎ is the Planck’s constant whose value is 6.62×1E-34). This was a significant departure from classical physics; it assumed that Energy was continuous and could be divided infinitely. Planck's theory of quantization allowed for the explanation of black body radiation and provided a foundation for the development of quantum mechanics, which has revolutionized modern physics. This was important in its own right and paved the way for many other important discoveries in physics. For example, it led to the discovery of the photoelectric effect, which demonstrated the wave-particle duality of light and helped lay the groundwork for the development of quantum mechanics. This discovery was later expanded upon by Albert Einstein, who proposed that light consists of discrete particles called photons. “After Max Planck became a professor at Berlin University, he tried to elucidate Wien's law that his colleague Wilhelm Wien had discovered in 1896. To support the entropy law, he wanted to develop a theoretical foundation for it based on the second law of thermodynamics”. References: [1] Longair, M. (2020). 1895–1900: Planck and the Spectrum of Black-Body Radiation. In Theoretical Concepts in Physics: An Alternative View of Theoretical Reasoning in Physics (pp. 348-372). Cambridge: Cambridge University Press. [2] D. F. Gray, “The black body and its radiation,” in The Observation and Analysis of Stellar Photospheres, 3rd ed., Cambridge: Cambridge University Press, 2005, pp. 118–126. [3] LEMONS, D.O.N.S. (2022) On the Trail of Blackbody Radiation: Max Planck and the physics of his era. S.l.: MIT PRESS. “Planck’s ‘First Derivation,’ 1900– 1901.” On the Trail of Black-body Radiation, 20 Oct. 2022, pp. 119–128. [4] Gearhart, C. (2009). Black-Body Radiation. In: Greenberger, D., Hentschel, K., Weinert, F. (eds) Compendium of Quantum Physics. Springer, Berlin, Heidelberg. [5] Klein, M. J. (1962). Max Planck and the Beginnings of the Quantum Theory. Archive for History of Exact Sciences, 1(5), 459–479. [6] “Energy in packets – What did Max Planck discover?,” Energy in packets – What did Max Planck discover? Max-Planck-Gesellschaft. [7] “Max Planck,” Physics Today, 23-Apr-2019. [Online]. [8] “Origin of quantum mechanics II : The quantization of EM Field,” Origin of Quantum Mechanics II : The Quantization of EM field. [Online]. [9] “6.2: Black-body Radiation,” Physics LibreTexts, Nov. 01, 2016. Mr. Devin Hansa de Silva B.Sc.(Honours) Reading Department of Computer Science, Faculty of Applied Sciences, University of Sri Jayewardenepura. December 2023 | Issue 01 03 Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01
READY ... ARE WE READY FOR THE NEXT TECHNOLOGICAL REVOLUTION BY QUANTUM COMPUTING MACHINES? This article is compiled to reach the general audience. So, we have avoided the technical details and rigorous mathematical notations. Classical mechanics is the study of the motion of everyday objects in accordance with the general principles developed by Newton. Quantum mechanics is a set of mathematical principles that attempts to explain the behavior of atoms and sub-atomic particles. Gordon E. Moore, co-founder of Intel, stated in 1965 that the number of transistors on a computer chip doubles approximately every two years, a phenomenon known as Moore's law. It is not a law of nature, but an observation of long-term technological change. About 42 years ago, that is in 1981, Richard P. Feynman proposed harnessing quantum physics to build a more powerful kind of computer – a quantum mechanical computer for simulating complex physical systems. Since then, the field was progressing slowly and later, in 1994, there was a boom in quantum computation with the introduction of an algorithm for factoring a composite number on a so-called quantum computer by Peter Shor who is a mathematician at Massachusetts Institute of Technology. What is a quantum computer? Quantum computers exploit the strange ability of subatomic particles to exist in more than one state at any time. Due to the way the extremely small particles behave, quantum computing operations can be performed faster, and consume less energy, than classical computers. In classical computing, a bit is a single piece of information that can exist in two states- 1 or 0. Quantum computing uses quantum bits, or ‘qubits’, instead. These are quantum systems with two states. However, unlike a usual bit, they can store much more information than just 1 or 0, because they can exist in any superposition of these values. Moore's Law, coined by Intel co-founder Gordon E. Moore in 1965, highlights a key trend in computer technology: a doubling of chip transistors approximately every two years, symbolizing rapid advances in computing. Source: https://physicsworld.com/ IBM Osprey 433-qubit superconducting quantum computer The growth of the number of transistors packed into a single integrated circuit December 2023 | Issue 01 04 Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01
“From superconducting qubits and photonic systems to neutral atoms and trapped ions, each quantum computing approach offers unique capabilities. Innovations like quantum dots and alternative methods further expand this cuttingedge field's potential”. Qubits are considered as separated physical objects with two possible distinct states, 0 and 1. The difference between classical bits and qubits is that we can also prepare qubits in a superposition of 0 and 1 and create nontrivial correlated states of a number of qubits, so-called entangled states. Classical bits can be in two states - at either of the two poles of a sphere; a qubit can exist at any point on the sphere. This means a computer using these bits can store far more information while consuming less energy than a conventional computer. How do quantum computers work? Since quantum computers are not limited to binary states (0 or 1), they encode information into qubits, which can exist in superposition (when two waves or states meet and overlap or interact). Qubits represent atoms, ions, photons, or electrons and their respective control devices that are working together to act as computer memory and processor at the same moment. Because a quantum computer can maintain multiple states simultaneously, it has the potential to be millions of times more powerful than current supercomputers. Quantum computers will harness the power of these atoms and molecules (rather than silicon- based processor chips) to perform memory and processing tasks. Quantum computers are capable of performing some calculations faster than any silicon computer. One of the ongoing challenges in quantum computing has been the capacity of computer chips. According to literature, for a functioning quantum computer, one needs to pack these chips with millions of qubits - bits that operate off the same concept as the binary bits that run your computer by signalling either 0 or 1, except that a qubit can exist as 0, 1, or as both of these potential states at once. Until now, it has been difficult to pack more than a few dozen qubits onto a chip. However, there is a new design that aims to overcome the issues, incorporating traditional elements with novel design to accomplish what has not been accomplished before. However, it is still in the testing phase. Leading Types of Quantum Computers Currently, there are a handful of different approaches to how quantum computers are developed and manufactured. Superconducting: One of the most popular types of quantum computers is a superconducting qubit quantum computer. Usually made from superconducting materials, these quantum computers utilize tiny electrical circuits to produce and manipulate qubits. When using superconducting qubits, gate operations can be performed quickly. Photonic: These types of quantum computers use photons (particles of light) to carry and process quantum information, and there is some nuance and complexity to how this works. For large-scale quantum computers, photonic qubits are a promising alternative to trapped ions and neutral atoms that require cryogenic or laser cooling. Photonics is a very good example of how Photonics is a general category used to bucket quantum computers. Neural Atoms: Quantum computing based on neutral atoms involves atoms suspended in an ultrahigh vacuum by arrays of tightly focused laser beams called optical tweezers, though not all neutral atom companies use optical tweezers. Neutral atom quantum computers are less sensitive to stray electric fields, which makes them a good option for quantum processors. Trapped Ions: A trapped ion quantum computer involves using atoms or molecules with a net electrical charge known as “ions” that are trapped and manipulated using electric and magnetic fields to store and process quantum information. As trapped ions can be isolated from their environment, they are useful for precision measurements and other applications requiring high levels of stability and control. Also, the qubits can remain in a superposition state for a long time before becoming decoherent. Quantum Dots: A quantum dot quantum computer uses silicon qubits made up of pairs of quantum dots. In theory for quantum computers, such ‘coupled’ quantum dots could be used as robust qubits. Other Approaches: Other alternatives to building a workable type of a quantum computer include electrons on helium, Nitrogen-Vacancy diamond and the topological approach. December 2023 | Issue 01 05 Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01
Few major industrial applications of quantum computing In the sequel, we list some crucial industrial applications of quantum computing. Artificial Intelligence (AI) and Machine Learning (ML): AI and ML have emerged as two of the key disruptive technologies influencing industrial automation. Nevertheless, implementing AI-powered solutions necessitates accuracy and fast processing, which could be difficult for traditional computer systems to handle. Cyber security and Cryptography: Cyber security has become a significant danger as the internet becomes the engine that propels companies and organizations to gain international momentum and boost user acquisitions. Quantum cryptography, a subfield of quantum applications, would also provide encryption techniques to impose higher security norms. Financial Automation: Finding the ideal investment possibilities with high returns and low-risk factors can be difficult for investors. But, with the creation of a useful quantum computing application, businesses would not only be able to carry out these calculations quickly and easily. Fraud Detection: To prevent fraudulent scenarios, industries like health care, banking, and marketing need reliable solutions for deriving functional entity relationships and data patterns. Data modeling can be made more efficient and timelier with the use of quantum computing. Weather Forecast: Another potential use for quantum computing would be in meteorology and weather forecasting. The weather forecasting techniques in use today that rely on conventional computers frequently take far longer than they ought to. Logistics Optimization: Businesses would naturally require a system that offers improved data analysis and reliable performance modelling to improve supply-chain management. The sophisticated quantum computing technology known as quantum annealing offers powerful answers. Defence: Quantum sensors have the potential to revolutionize military operations by providing unprecedented levels of precision and accuracy. For example, quantum sensors could detect the specific location of an enemy missile launch or identify the signature of a nuclear weapon. Healthcare: Radiotherapy is one promising application. Other possible areas of applications are drug development and testing, quantum imaging, modelling complicated molecular interactions at an atomic stage, DNA sequencing etc.
Current state of quantum computing in Asia and the situation in Sri Lanka China, India, Japan, South Korea and Singapore showcase excellence in quantum research and technologies in Asia while China plays a major role in building a real quantum computer. Japan pioneers in research related to developing to quantum cryptographic systems. The universities, higher education institutes and separately established research centers highly engage in building faulttolerant quantum computers. The other countries like Thailand, Malaysia and Indonesia are also in the forefront. In the Sri Lankan context, as per the author’s understanding, we have not paid any attention or just ignored research in quantum technology while a few are engaging in theoretical research. The situation is really pathetic and there is hardly any university or higher education institution offering courses related to quantum information science or doing serious research. The communication systems will be at a risk with the adoption of quantum computers as described above. So, the government should take necessary steps to take policy decisions without any further delay. Conclusion Quantum physics has opened doors to many areas of research. Quantum computing exploits the laws of quantum mechanics to solve problems too complex for conventional computers. Quantum communication is a field of applied quantum physics closely related to quantum information processing and quantum teleportation. Quantum sensing improves the accuracy of how we measure, navigate, study, explore, see, and interact with the world around us. It can be safely assumed that the first generation of quantum computers will eventually lead to the benefits we expect. However, quantum computing is still at its infancy and it will likely to take years to see a quantum computer on our table. Dr. Nihal Yapage, Department of Mathematics, Faculty of Science, University of Ruhuna, Matara Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01
Figure 1 Newspaper articles in May 1910. Source: Google Images. According to NASA definition the small bodies in the solar system include comets, asteroids, the objects in the Kuiper Belt and the Oort cloud, small planetary satellites, Triton, Pluto, Charon and interplanetary dust. As some of these objects are believed to be minimally altered from their state in the young solar nebula from which the planets formed, they may provide insight into planet earth and the formation and evolution of the solar system. The ‘Sacred Followers’ religious group in Oklahoma was planning to sacrifice a virgin to ward off the disaster but was stopped by the police. Comet pellets, comet masks, comet soap, and even renting submarines became commonplace in disaster preparedness. Meteors are also fascinated as same as comets. Both create spectacular moments in the night sky. Meteors get heated by air friction of the Earth’s atmosphere and become fireballs. Meteors can be either cometary particles or asteroidal particles. Cometary particles are very weak and they vaporize in the Earth’s atmosphere easily. Very rarely leftover particles reach the ground. If a meteorite is an asteroid, it is made of strong rocks and metals that may survive its fall through the atmosphere and end up in a crater on the ground. However, meteors are more fearful than comets, because scientists believe that about seventy-five years ago, about 75% of the animals precision Earth, including dinosaurs, became extinct due to a meteorite. A meteor shower is a series of meteors that appear to come from one place in the sky. Among all these small bodies, comets, asteroids and meteorites have occupied a significant place among humans since time immemorial. Greeks, Romans, and Asians believed comets, meteors and meteor showers as signs of portent. They believed the appearance of these small bodies was a sign of good or bad political and social events in the future. The appearance of a comet is considered a sign of the birth of a great fellow by Europeans. For example, three Persian Magi followed a comate to the birthplace of Jesus and in 44 BC, Julius Caesar’s adopted son Octavian interpreted the outburst of a comet as a sign of the deification of Julius Caesar and named it Caesar’s comet. In spite of that, the defeat of Attila the Hun by the combined RomanGotharmy was thought to be predicted by the appearance of comet Halley in the year 451 AD. SCIENTISTS BELIEVE THAT ABOUT SEVENTY-FIVE YEARS AGO, ABOUT 75% OF THE ANIMALS PRECISION EARTH, INCLUDING DINOSAURS, BECAME EXTINCT DUE TO A METEORITE. According to the theory of Wuxing (water, fire, earth, metal, wood), comets signifies the imbalance of yin and yang (opposite but interconnected, mutually perpetuating forces). For example, Emperor Ruizong of Tang abdicated after seeing a comet in 712 AD and the breakup of a comet on 25 January 35 AD was interpreted as portending the destruction of Gongsun Shu by Wu Han, General to emperor Guangwu. Not long before, on May 19, 1910, Halley's Comet scared people again. Earth passed through the tail of Halley's Comet, and millions of people were horrified when spectroscopically discovered that Cyanide gas was present in the Comet's tail. Many thought it was the end of life on Earth. According to reports, residents of Chicago stuffed cloth around doors, and windows to prevent the gas from entering. They have kept Oxygen bottles near them for any emergencies. In 1066 people in England believed the appearance of Halley’s comet was portending great change for the AngloSaxon kingdom ruled by King Harold. In contrast to this Duke William of Normandy believed it was a positive sign coming from heaven. He defeated Harold’s army and was crowned the King of England. Chinese people believed comets as bad omen. Small Bodies…. Hazardous or Blessed? December 2023 | Issue 01 08 Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01
Small body research at the Jet Propulsion Laboratory has discovered hazards in small bodies named as Near-Earth-Objects (NEOs). NEOs are asteroids and comets that orbit on paths that can come closer to the Earth’s orbit or cross the Earth’s orbit. JPL’s Solar System Dynamics (SSD) group is responsible for maintaining and improving the orbits of all small bodies in our Solar System. The Center for NearEarth Object Studies (CNEOS) focuses on the NEOs that closely approach the Earth. IN SCIENTIFIC VIEW, SMALL BODIES ARE CONSIDERED AS ‘BLESSED’ BECAUSE THEY ARE CONSIDERED AS IMPORTANT CELESTIAL OBJECTS THAT HIDE MORE DETAILS ABOUT THE FORMATION OF PLANETS. Figure 03: A graph showing near-Earth asteroid discoveries. Discoveries have ramped up since the early 2000s. Credit:NASA/CenterforNearEarthObjectStudies. At present, Astronomers have done enough studies about small bodies and they have identified two important regions ‘Oort Cloud’ and ‘Kuiper Belt’ as places where a collection of small bodies has gathered. They have also identified the distinguish among small bodies including their physical composition, path, and periodic behavior of comets. In scientific view, small bodies are considered as ‘Blessed’ because they are considered as important celestial objects that hide more details about the formation of planets. Comets are considered as the remains of the ice parts of the solar nebula while asteroids are rocky debris left over from planet building. Studying the small bodies reveals the conditions that were present at the formation of the solar system as well as the details of the evolution of the solar system upto the present time. On the other hand, small bodies are ‘Hazards’, because depending on the speed, angle of impact, and size they can destroy the planet Earth partially and cause harm to the people by creating deadly tsunamis. The meteors in the meteor showers are normally dust and debris released from the nucleus of a comet. When the Earth passes near or through the orbital path of the comet it enters the Earth’s atmosphere giving the sense of a falling star. Since long time ago people believed their wish could be fulfilled by wishing on a shooting star. According to old Indian astrology, meteors also can predict both good and bad signs. As mentioned in the book ‘Wruhathsanghitha’ meteors have been classified into five main categories and each category has its own predictions. The SSD group continuously monitors the motions of these objects by improving knowledge of their orbits. CNEOS performs statistical studies to identify future Earth close approaches and, for objects of particular interest, computes Earth- impact probabilities. They provide impact probabilities to observers around the world, highlighting which objects require new data to rule out future impact possibilities. Saumya Kumari A. P. Reading for the PhD Department of Physics, University of Colombo. Figure 02: Predictions based on meteors by ancient Indian astrologer Varagambheerachaary a. Source: Wruhathsanghitha – translated by Balandoda Ananda Maithree tero. December 2023 | Issue 01 09 Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01
The world's insatiable demand for energy, coupled with growing concerns about climate change, has driven scientists to search for cleaner and more sustainable sources of power. One of the most promising solutions on the horizon is nuclear fusion, a process that replicates the very energy generation mechanism of stars. This article delves into the potential of fusion energy, the challenges faced in achieving it, and the latest developments in fusion research that bring us closer to realizing its vast potential. Nuclear fusion is a process that differs fundamentally from the nuclear fission reactions used in today's nuclear power plants. While fission involves splitting atoms to release energy, fusion involves combining two light atomic nuclei to form a heavier nucleus. The fusion process that powers the sun and other stars is based on this very principle, fusing hydrogen atoms into helium, and it offers several advantages for energy production on Earth. The advantages of nuclear fusion are immense. Fusion uses isotopes of hydrogen, deuterium, and tritium, as its fuel, which are readily available from water and lithium. Unlike fission, fusion produces minimal nuclear waste and no long-lived, highly radioactive materials. Most importantly, fusion has the potential to provide a nearly limitless supply of clean energy while producing no direct greenhouse gas emissions. Fusion as an energy source has been the dream of scientists for decades. The journey to harness the power of the stars has been marked by a series of milestones and challenges. Early fusion researchers faced numerous difficulties, including the need to achieve the extremely high temperatures and pressures required to initiate fusion reactions. UNLOCKING THE POWER OF THE STARS: THE QUEST FOR FUSION ENERGY One of the primary technical challenges in controlled nuclear fusion is achieving the conditions necessary for a sustained reaction. At its core, fusion requires extreme heat and pressure to force atomic nuclei to overcome their natural electrostatic repulsion and collide with enough energy to fuse. This phenomenon is often referred to as "ignition." Scientists have developed various methods to approach the challenges of fusion. Two of the most prominent approaches are magnetic confinement, such as tokamaks, and inertial confinement, which uses powerful lasers to compress and heat a tiny fuel pellet to the required conditions for fusion. Recent developments have demonstrated significant progress in both approaches. For instance, the International Thermonuclear Experimental Reactor (ITER) project, located in France, represents a significant step toward achieving controlled nuclear fusion. December 2023 | Issue 01 10 Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01
ITER aims to demonstrate the feasibility of fusion as a large-scale and carbon-free source of energy. The achievements of ITER and other international efforts provide hope that commercial fusion energy production is within reach. Private companies have also entered the fusion arena, with their own ambitious goals and innovations. With these combined efforts, the world may soon witness a breakthrough in fusion energy. The environmental advantages of fusion energy cannot be overstated. It has the potential to revolutionize the global energy landscape by providing a clean, virtually limitless source of power. Fusion produces minimal radioactive waste and does not release harmful greenhouse gases, making it a critical part of addressing climate change. Economically, the widespread adoption of fusion energy could significantly reduce energy costs and increase energy security. With abundant fuel sources and reduced environmental impact, fusion has the potential to transform the way we power our world. Public perception and support for fusion research are vital to its success. Despite the overwhelming potential benefits, fusion still faces skepticism and misconceptions. It's essential to educate the public about the science and potential of fusion energy, as well as the importance of continued research and investment. The quest for fusion energy is an exciting journey into the heart of the stars. While challenges remain, we are making significant strides in the field of fusion research. As we move closer to unlocking the power of the stars, fusion energy offers a path to a cleaner, sustainable, and brighter future for all. Your interest and advocacy can contribute to the realization of fusion energy's full potential, bringing us closer to a future powered by the stars. Together, we can unlock the key to sustainable, limitless energy. References: [1] J. Martinez, Remarks on Nuclear Fusion Energy: Advantages, and Disadvantages, Available SSRN 4109155. (2022). [2] B.W. Brook, A. Alonso, D.A. Meneley, J. Misak, T. Blees, J.B. van Erp, Why nuclear energy is sustainable and has to be part of the energy mix, Sustain. Mater. Technol. 1 (2014) 8–16. [3] J.R. McNally Jr, Physics of fusion fuel cycles, Nucl. Technol. 2 (1982) 9–28. [4] G.S. Was, D. Petti, S. Ukai, S. Zinkle, Materials for future nuclear energy systems, J. Nucl. Mater. 527 (2019) 151837. [5] R.A. Gross, Fusion energy, (1984). [6] D.M. Duffy, Fusion power: a challenge for materials science, Philos. Trans. R. Soc. A Math. Phys. Eng. Sci. 368 (2010) 3315–3328. [7] J. Parisi, J. Ball, The future of fusion energy, World Scientific, 2019. [8] J. Ongena, G. Van Oost, Energy for future centuries: Prospects for fusion power as a future energy source, Fusion Sci. Technol. 61 (2012) 3–16. Lahiru Abeykoon (MPhil, BSc (Sp.in Applied Physics)), Research Scientist Materials Technology Section Industrial Technology Institute Colombo 07 IT HAS THE POTENTIAL TO REVOLUTIONIZE THE GLOBAL ENERGY LANDSCAPE BY PROVIDING A CLEAN, VIRTUALLY LIMITLESS SOURCE OF POWER. December 2023 | Issue 01 11 Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01
December 2023 | Issue 01 13 In the ever-evolving landscape of knowledge and innovation, the undergraduate years are far more than just a stepping stone to professional endeavors or a passive phase for securing opportunities for higher education. These years are a critical time for intellectual growth and change in thinking. Starting research during this formative period is essential, driven by the need for educational development, personal growth, and societal contribution. Research, at its heart, is a quest for truth through detailed scientific investigation and analysis. When undergraduates begin their research journey early, they embark on a path to academic excellence. This research journey not only provides an opportunity to uncover specific facts but also linking dif erent concepts which most of the undergraduates find challenging. This in-depth exploration takes students beyond simple memorization, fostering a deep understanding of their subjects and leading them towards both academic and research excellence. Early research is vital in cultivating critical thinking and problem-solving skills. It challenges students to question established ideas, analyze problems carefully, and merge information from dif erent sources. These abilities are crucial for academic achievement and are invaluable for navigating the complexities of modern life. Furthermore, early research experience provides a competitive advantage in the job market, showcasing a student's proactive and innovative mindset. It also acts as a strong indicator of academic commitment, often a requirement for entry into prestigious graduate programs. When choosing between two graduate students, one with early research experience and scientific publications, and the other with just good grades, the natural choice would be the one with research experience. Beyond professional benefits, research nurtures personal growth. It teaches resilience, as students learn to face and overcome the inherent challenges of research, building grit that serves them well in all aspects of life's aspects. It also provides a route to self-discovery, assisting students in finding their passions and potential career paths, a process that many students often depend on through trial and error. Moreover, when undergraduates engage in research, they contribute significantly to the collective pool of knowledge. Their fresh perspectives and creativity can lead to breakthroughs, even in areas that may have been overlooked by more experienced researchers. This contribution benefits not only the students but also society at large. Therefore, the encouragement for undergraduates to commence research early is more than just advice; it signifies a pivotal shift in our approach to undergraduate teaching and learning. Educators and institutions must foster environments that not only allow but actively encourage research. Embarking on an Odyssey of Discovery: Why it is important for Undergraduates to Begin Research Early Dr DL Weerawarne Senior Lecturer Department of Physics University of Colombo In doing so, we are not only educating informed students but also shaping the future's leaders and innovators. If you're an undergraduate, don't wait until your final year to start research. Start now! Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01
FUTURE Electrochromic Devices (ECDs) utilize the color-changing properties of electrochromism for applications in smart windows, energy storage, and wearable technology. These innovative devices blend energy efficiency with functionality, revolutionizing how we interact with technology in buildings and fashion. Electrochromism is the phenomenon which changes transmittance or reflectance reversibly when an appropriate current or potential is applied on it. Applying electric current or potential leads to the reduction of Electrochromic material, and it causes the generation of different visible region electronic absorption bands. The change of transmittance is due to the colour change of the electrochromic (EC) material. The color change of Electrochromic material is usually between a transparent (bleaching) state and a colored state or between two colored states. Electrochromic materials that possess potentially useful electrochromic properties can be grouped into two categories: inorganic and organic systems. Prussian blue (iron hexacyanoferrate, Fe4[Fe(CN)6]3) and transition metal oxide-based (TiO2, WO3, Nb2O5, MoO3, IrO2, MnO2, etc.) systems have long been the two main categories of inorganic electrochromic materials. Numerous organic substances, such as conjugated polymers, viologens, and transition metal-ligand complexes, have electrochromic characteristics. Coloring or bleaching of the EC material is a consequence of the insertion or extraction of electrons or metal ions in/from the EC material. As this color-control technology produces visually accessible information; we would anticipate that a far greater range of functional devices would have used the visualization technique. Actually, according to some recent research findings, the growth of electrochromic technology has been strongly aided by its integration with other cutting-edge technologies, expanding its potential applications across a range of industries. The wide range of variations in the properties and makeup of electrochromic materials offers a strong foundation for attempts to combine electrochromic technology with other cutting-edge technologies like wearable, thermal control, energy harvesting, energy storing, and sensing. ELECTROCHROMIC DEVICES (ECD) FOR FUTURE DEVELOPMENT An electrochromic device (ECD) is composed of three components; a working electrode (EC electrode), an ion transportation medium(electrolyte), and a counter electrode. They are arranged in a layered, “sandwich” type configuration in which a working electrode and a counter-electrode (CE) are physically separated but connected by ionconducting liquid, quasi-solid (gel), or solid electrolyte. When the ECD is subjected to an electric field, it undergoes reversible color change according to the insertion or extraction of metal ions or electrons in the electrolyte. Electrochromism has significant commercial potential as well as significant social value in terms of green energy savings. Currently, a significant portion of the world's energy consumption (approximately 41%) is used to maintain a comfortable light and temperature environment inside buildings. The ability to independently control visible and near-infrared radiation (NIR) light is a key goal for nextgeneration smart windows, which could adjust the amount of sunlight and heat entering a building. Such dual-function ECDs can adjust the sunlight and solar heat inside the building and at the same time can be used as energy storage device. Apart from that, stretchable and wearable electrochromic devices are tested for application in future smart clothes. The goal is to create highperformance fabrics with intriguing electrochromic properties that could reshape the fashion industry with controlled color designs in clothing. December 2023 | Issue 01 14 Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01
Supercapacitors and batteries are the two most common types of energy storage systems. Because electrochromic devices and supercapacitors/batteries have some similarities, such as electrodes, device structures, and reaction kinetics, it is possible to combine electrochromic technology with supercapacitors/batteries to create electrochromic energy storage devices. Also, their work principles are both based on redox reactions of electrode material. Thus, if the electrode material changes colors between oxidation and reduction states, it could function as both a supercapacitor and an electrochromic device. In such cases, electrochromism and a supercapacitor can be combined into a single device that can be used not only for energy storage but also as an electrochromic window. Although the required power consumption is low, typical electrochromic devices require external energy supplies to implement the color changing function. The incident sunlight energy can be used to drive the coloration of ECDs without requiring additional electrical connections. Electrochromic devices have inherent advantages in signal output that can be determined simply by color variation. The combination of sensing technology and electrochromic technology allows for rapid visual recognition of sensing information, and detection results can be read directly with the naked eye by the color of electrochromic devices. This can be used in many applications such as electrochromic chemosensors, electrochromic biosensors, electrochromic gas sensors, electrochromic mechanical sensors. Dr. H.N.M. Sarangika Department of Physical Sciences and Technology, Faculty of Applied Sciences, Sabaragamuwa University of Sri Lanka Figure 01. Schematic diagram of the Electrochromic Device Figure 02. Real image of the fabricated Electrochromic Device and Transmittance variation of the Electrochromic Device Figure 03. Future application of the Electrochromic Device December 2023 | Issue 01 15 Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01
Medical imaging is the visualization of interior body for diagnostic purpose, treatment purposes and frequently monitoring in the follow up of patients. “Positron Emission Tomography” (PET) is a powerful and unique modality compared to other imaging modalities. Its versatility and ability to cover the whole body, providing functional imaging inside the body, providing measurement of metabolic and physiological processes in the human body, early disease detection, non-invasive procedure, real-time monitoring, ability to combine with CT and MRI and diagnostic accuracy, making it a valuable tool in the field of medical imaging. A small amount of positron emitting material, called “PET tracer” is injected into the bloodstream through a vein of the patient at the beginning of the scan. Short lived positron emitting isotopes such as C11, N-13, O-15, F-18 are incorporated into biological active molecules such as glucose, H2O, NH3, CO2, O2 to design the PET tracer. Injected positron emitting, biological active, molecules concentrated into the disease inside the human body and provides information of biological function. The most commonly used tracer in PET scanning is fluorodeoxyglucose (FDG), which has a half-life of nearly two hours. FDG is a sugar compound derived by a special chemical reaction between a glucose molecule and a positron emitting fluorine-18 (F-18) atom. Positron emitting F-18 atoms are produced by bombarding targeted oxygen18 (O-18) enriched water with accelerated protons. Cyclotron is the device that accelerates protons along a horizontal spiral path using a horizontal electric field and a vertical magnetic field. Protons obtain sufficient energy in the acceleration process to produce F-18 after bombarding with oxygen-18 atoms in water. Because of FDG has sort half-life, onsite cyclotron near the PET scanner is more cost effective. Human cells use glucose to produce energy in different quantities and rates for normal functioning of the organs. Since FDG is similar to glucose, injected FDG travels through the body and accumulates in the body tissues and organs with different concentration. Cancer cells produce more energy using glucose and grow faster than healthy tissues. Furthermore, the glucose absorbing rate is related to the stage of the cancer. Therefore, high concentrations areas of FDG such as cancer produce high concentration of positron. Positrons that are released by the F-18, interact with neighboring electrons in the human cells. This interaction is known as annihilation. In the annihilation, positron and electron convert their mass into two gamma rays with the energy of 511 keV according to the Einstein's equation E = mc , where m is the mass of the electron and positron and c is the speed of light. Annihilation gamma rays travel in opposite directions and The PET scanner measures the exact location and timing of gamma ray emissions by tracking the paths of both gamma rays. INSPECTOR OF CANCER - PET 2 December 2023 | Issue 01 16 Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01
Olivia Wilson / Larana Magazine Photo credit It is very important that PET scans require careful prepreparation. Patient will receive specific instructions based on the nature of the PET scan that he or she is undergoing as well as his or her health conditions. Therefore, patient should consult about recent medical conditions, medications, allergies by the physician prior to the PET scan. Especially diabetic patients will receive special instructions before the preparation to PET scanning. Women should always inform their doctor regarding the possible pregnancy and her breast feeding conditions. Patients should refrain from liquids or meals which are rich in carbohydrate and sugar as well as chewing gum or mints, day before the PET scan. All the meals including liquids should be stopped several hours before the scan. However, drinking water until the scan, is encouraged for best scanning results. Accessories such as jewelries, spectacles and pins should be removed prior to the scan. Patient may be advised wear comfortable clothes during the Scan. After 45- 60 minutes relaxation time from the injection of FDG, patient is sent to the PET scanning machine for the scan. The important role of PET scanning is its ability to provide 3D visual representation of the functions inside the body at the molecular and cellular level. As a result, it can detect the disease earlier than the other medical imaging techniques. However the integration of PET and Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) scanners into a single imaging system provides a versatile approach to medical imaging. Integrated PET scanner with a CT scanner referred to as a PET-CT scanner. It offers improved diagnostic accuracy, facilitates treatment planning, and enhances the ability to understand both the anatomical and functional aspects of the body. Patient has least side effects from PET scan, because radiation level of FDG is extremely low and it decays naturally within a short period of time. Shape of the typical PET scanning machine is a large box and doughnut shaped tunnel in the middle. PET scanners have rings of small gamma ray detectors around the doughnut shape, and these detectors are capable of detecting the both gamma rays produced during annihilation. There are primarily three types of detectors used in PET called Scintillation detectors, Photomultiplier tubes and Semiconductor detectors. Scintillation detectors are based on the principle of scintillation. When gamma rays interact with a scintillating crystal material, they generate large number of visible light photons. These visible lights are then converted into electrical signals. Scintillation detectors commonly made of Scintillation materials like Bismuth Germanate (BGO), Lutetium Yttrium Orthosilicate (LYSO), or Sodium Iodide (NaI). Scintillation detectors have been introduced to PET systems several decades ago, but it is still widely used in clinical PET scanners due to their proven performance and reliability. Photomultiplier tubes consists tiny Silicon photo electrode system to convert gamma rays to electric signals. Semiconductor detectors are a more recent development in PET technology. It is made from semiconductor material, Cadmium Zinc Telluride (CZT) and offer good energy resolution and sensitivity. During scanning time, the patient has to lie without moving on a narrow flat table type bed that moves into and out of this tunnel. Computer coupled ring of gamma ray detectors within the tunnel record annihilation gamma rays emitted from the body. By tracking the paths of these gamma rays and their annihilation events, the scanner can create a three dimensional (3D) image that represents the distribution of FDG in the body. Detecting two gamma rays in the same time is an important advantage of the PET imaging. Annihilation point can be calculated accurately by measuring both gamma rays. Full body PET scans can be used to determine spread of the cancer to other areas of the body. A well trained team of specialist including Radiologist, medical physicists, radiographers and nurses involve in optimizing the scanning process. Finally, patient may be discharged after several minutes from the scan and Radiologist will take few days to discuss and explain the result. “THE IMPORTANT ROLE OF PET SCANNING IS ITS ABILITY TO PROVIDE 3D VISUAL REPRESENTATION OF THE FUNCTIONS INSIDE THE BODY AT THE MOLECULAR AND CELLULAR LEVEL”. volume ii References [1] Daghighian F, Sumida R, and Phelps ME;PET Imaging: An Overview and Instrumentation; Journal of nuclear medicine technology; 18; p5-13; 1990. [2] Humm JL, Rosenfeld A, Guerra AD; From PET detectors to PET scanners; European Journal of Nuclear Medicine and Molecular Imaging; 30 (11); P 1574-1597; 2003. [3] Bailey DL, Townsend DW,Valk PE and Maisey MN; Positron Emission Tomography; ISBN 1-85233-798-2; Springer-Verlag; London; 2005. Mr. T R C K Wijayarathna BSc (Physics Sp.), PGEC, MSc, MPhil, MIP Medical Physicist National Hospital Kandy Sri Lanka December 2023 | Issue 01 17 Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01
Óúhg .%yl fyda OQufla;= j,ska we;sjk n,mEï fuhska jir ñ,shk 65la muK wE; w;S;fha isg jd¾;d ù we;' m fï ms<sn| oekqj;a ùfï jeo.;alu ksid 2014 isg iEu jirlu cQks 30jeks Èk f,dal .%yl Èkh f,i tlai;a cd;Skaf.a ixúOdkh m%ldYhg m;a lr we;' fuu Èkh .%yl Èkh f,i fhdod .ekSug fya;= ù we;af;a 1908 cQks 30 fjks Èk reishdfõ ihsîßhd m%dka;fha ;=ï.=iald ^Gqka.=ald m%foaYhg lvdjegqKq óg¾ 60l muK W,aldmd;fhka isÿjQ úkdYhhs' uE; ld,fha mDÓúh wdikakfhka .uka l, .%yl úYd, m%udKhla jd¾;d úh' fuhg fya;=j j¾;udkfha fuu .%yl ksÍlaIKh lr tajdfha .uka u. ksj/Èj ks.ukh l, yels ;dlaIKh iy ta i|yd ia:dms; lr we;s mDÓú uOHia:dk fõ' weußldfõ weßfidakd m%dka;fha msysá leg,skd wyi ksÍlaIK uOHia:dkh ^Cwfg,sSW¾fjha& .%yl wkdjrKh iy ksÍlaIKhg fjkajQ ksÍlaIKd.drhls' miq.sh uehs ui 15 jk Èk 2010WC9 .%ylh mDÓúfha isg lsf,da ógr 203000 la ÿßka we§ .sfhah' fuys úYd,;ajh ógr 60 - 130 la muK jQ w;r fuh 1908 ;=ï.=iald ^Gqka.=iald W,aldmd;hg jvd úYd, úh' fujeksu ;j;a isoaêhla 2018 wfm%,a 15 jk Èk jd¾;d úh' 2018 >aE3 kï jQ .%ylh mDÓúhg wdikakj .uka lsÍug Èklg m%:u fidhd.;a w;r mDÒúfha isg lsf,da ógr 192200 la ÿßka" tkï mDÓúh iy pkaøhd w;r ÿßka wvla muK ÿrlska .uka lr we;' fuu .%ylfha úYd,;ajho ógr 48 - 110 ;a muK úh'fuu isoaêfhka fmkS hkafka fl;rï ;dlaIKh ÈhqKq jqj;a fl;rï ksÍlaIKd.dr ;snqK;a wmg fkdoekS .%yl mDÓúhg <Õd ù ukqIH j¾.hdg ;¾ckhla úh yels nj fkdfõo@ 2017 Tlaf;daïn¾ ui 18 jk Èk Y%S ,xldfõ ol=Kq È. wyfia o¾Ykh jQ úYd, W,aldmd;ho fujeksu isoaêhls' fuu isoaêh fndfyda fofkl= ;=, l=;=y,hla we;s flfrkq w;r th l=ula jkakg we;aoehs oekqj;a fkdùh' mDÓúhg ;¾ckhla úhyels .y% l iy Ouq fl;a = D fl%fÜiSh hq.h wjika lrfm,sfhdamska hq.fha wdrïNh isÿùu ;ju;a úoHd;aul wNsryila jk kuq;a ta i|yd mDÓúhg wd.ka;=l f,i meñ‚ b;d úYd, .,a lene,a,la fyda OQufla;=jla fya;= jkakg we;ehs úYajdi flf¾' fulaisfldafõ msysá úIalïNh lsf,daógr 180 jk fplaiq,ì ^ýcxW¨í& wdjdgh jir ñ,shk 65 muK jhi ùu;a vhsfkdairhka j|ùu iuÕ hï lsis iei£ula fmkakqï lrhs'ta wkqj vhsfkdairhkaf.a j|ùu W,aldmd;hla fyda OQufla;=jla mDÓúh iuÕ >Ügkh ùfuka jQjd hehs hk u;h neyer l, fkdyel' fojkqj ñksid o@ ñksidg;a fuu brKu w;afõ o@ vhsfkdairhka yd iuÕ ii|k l, ñksid isákafka úoHdj iy ;dlaIKh w;ska w;s woaú;Sh ia:dkhlh'W,aldmd; iy OQufla;= .ek wm okakd lreKq fndfyda jqj;a tuÕska we;súhyels jHjikh fok n,k úg wm ish¨ fokd fï ms<sn|j hï ;dla ÿrg oekqj;a ù isáh hq;=h' (Chicxulub) (Tunguska) (Catelina Sky Survey) 2010WC9 (Tunguska) 2018GE11 ksj/Èj y÷kd.;a W,aldmd; fldgia PdhdrEm wka;¾cd,h weiqßka December 2023 | Issue 01 18 Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01
fï ksid W,aldmd;hla hkq l=ulaoehs oekqj;a ùu ldf,daÑ; fõ' mDÓúh we;=¿ ish¨u .%y jia;= wNHjldYfha ksr;=rej p,kh fjñka mj;S' tfukau fikaá óg¾ lsysmhl isg lsf,daógr ish.Kkla olajd úYd, .,a len,s fuu wNHjldYfha ksrka;rfhka ta fï w; .uka lrhs' fuu .,alen,s mDÓúfha .=re;ajdl¾IKhg k;=ù mDÓúhg lvd jeàu ksrka;rfhka isÿjk kuq;a b;d >k mDÓú jdhqf.da,h uÕska fuu uOH m%udKfha .,alen,s by, wyfia § úkdY lr ouhs' ie,lsh hq;= ;rï m%udKfha wd.ka;=lfhla tkï óg¾ 5-10 muK jk .,a len,s iïmQ¾Kfhkau oeù fkdf.dia f.dvìug lvd jeàug yelshdjla we;'tfia mDÓúh u;g jefgk W,aldIau ^Mtfgfr W,aldmd; ^MgTßfÜ f,i ye¢kafõ' W,aldmd; m%Odk jYfhka j¾. 3lg fjka flf¾' tajd kï mdIdKkuh W,aldmd;" hlv wvx.= W,aldmd; iy mdIdK iy hlv ixfhdackh jQ W,aldmd; fõ' mdIdK ^dkaha& W,aldmd; j, is,sflag wvx.= jk w;r"hlv W,aldmd; j, m%Odk jYfhka hlv wvx.= fõ' Bg wu;rj hlv W,aldm; j, ksl,a" f,â jeks nr uQ,øjHo wvx.= fõ' 2017 Tlaf;daïn¾ ui 18jk Èk Y%S ,xldjg o¾Ykh jQ W,aldmd;fha fldgia yuqjQ njg ol=Kq m%foaYfha ia:dk lsysmhl§ jd¾;d úh' tu mdIdK fldgia i;H jYfhkau W,aldmd;o ke;fyd;a mDÓú mdIdK fldgiao hkak ;yjqre lr .ekSu ;rula wmyiq lghq;a;ls' flfia fj;;a fuu mdIdK fldgia ir, mÍlaIK lsysmhla uÕska hï uÜgulg wNHjldYfhka meñ‚fhao hkak ks.ukh l, yel' m<uqj mdIdK j, u;=msg iajdNdjh ksÍlaIKh lsÍfuka fuu ielh ;yjqre lr.; yel' WodyrKhla f,i my; rEm igyka j, fmfkk wdldrhg W,aldmd;hl u;=msg oeä f,i ms,siaiqï iys; ,laIK oelsh yel' ;jo fndfydauhla W,aldmd; j, hlv ksid pqïNl j,g weo .ekSfï n,hla we;' W,aldmd; j, ner f,day wvx.= ksid idudkHfhka >k;ajh by, w.hla .kS' mDÓúfha we;s yqKq.,a";sßjdk fyda .%ekhsÜ j, >k;ajh 23 .a$ï w;r mj;S' kuq;a W,aldmd;hl idudk >k;ajh 7-8 .a$c muK fõ' tkï W,aldmd;hl úYd,;ajh iuÕ ii|d ne,Sfuka w;g oefkk nr jeä fõ' mDÓúh u;g m;s; jk W,aldmd; j, jákdlu ñ, l, fkdyels ;rï fõ' ukao fuu W,aldmd; len,s j,ska fi!r.%y uKav,fha Wm;" mDÓúh u; Ôjh ìysùu jeks u;fíohg ;=vq § we;s m%Yak .Kkdjlg ms,s;=re fiúh yels neúks' fï ksid fuu wd.ka;=l .,a len,s ksj/Èj y÷kd.; hq;= w;r tajd ms<sn| f;dr;=rla fjf;d;a wd;¾ iS' la,dla wdh;kfha ;drld úoHd wxYhg oekaùu uÕska ;drld úoHdjg iïnkaO jeo.;a m¾fhaIK j,g odhl;ajh ,nd Èh yel' wdpd¾h ckl wviaiQßh ;drld iy wNHjldY úoHd tallh fN!;sl úoHd wxYh fld<U úYajúoHd,h (Meteoroid) (Meteorite) (Stony) g/cm 3 g/cm 3 W,aldmd;fuka fmfkk mDÓú mdIdK PdhdrEm wka;¾cd,h weiqßka December 2023 | Issue 01 19 Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01
Èfkod Ôú;fha § úúO ;r,hkays ÿi%dù;dj Tn wm ukdj w;a oel we;' c,hg t idfmalaIj óme‚ j, ÿi%dù;dj ridhksl úoHd;aulj ÿi%dù;dj foi i,ld ne,Sfï§ ;r,fhys wKqj, m%udKh" yevh" idkaøKh iy wka;¾ wKql wka;¾l%shd ms<sn|j jvd;a ie,ls,su;a fõ' úYd, wKq iys; ;r, j, ÿi%dù;dj ^Wl= nj& l=vd wKq iys; ;r, j,g jeäùu ksÍlaIKh fõ' ridhksl úoHd;aulj" úYd, wKq iys; ;r,j, ÿi%dù;dj wêl ùfï ixisoaêh" tu wKqj, mDIaÁh j¾.M,h jeäùu fya;=fjka >¾IKh tys by,hEu ;=,ska w¾: olajd we;' tf,igu wka;¾ wKql wdl¾IK n, úúO;ajh fya;=fjka ÿi%dù;dfjys fjkialï ksÍlaIKh fõ' wêl wka;¾ wKql n, we;s ;r,hkays wKq tlsfklg wdYla; ùfuka tys idfmalaIj by, ÿi%dù;djla olakg ,efí' ÿi%dù;dj flfrys úúO idOl n,mdkq ,efí' ta ms<sn|j i<ld n,uq' tkï wKqj, m%udKh iy yevh" wKql wka;¾l%shd" ;r,fhys WIaK;ajh iy ;r,h u; fhfok mSvkh ie,lsh yel' ixlS¾K iy È.= yeve;s wKq iys; ;r,hkays ÿi%dù;djh" ir, iy f.da,dldr wKq iys; ;r,hkays ÿi%dù;djg idfmalaIj by, fõ' ;r,hl WIaK;ajh by,hEfï§ wKqj, p,kh fõ.j;aj isÿjk w;r >¾IKh my< hEu fya;=fjka tys ÿi%dù;dj my< hhs' ;r,hka u; fhfok mSvkh fya;=fjka wKq ,xùfuka wka;¾ wKql mr;rh wju ù ÿi%dù;dj by, hhs' ;r,hkays wkaùlaISh iy ufyalaI .=K ^ñcfrdiacTmsc wkaâ ucfrdiacTmsc fma& ÿi%dù;dj flfrys flfia n,mdkafka oehs i,ld n,uq' wKqj, m%udKh iy yevh ;r,fhys ÿi%dù;dj flfrys n,mdk wdldrh by;§ idlÉPd lf,uq' úúO wdl,k øjH ^wâäáfa& fh§fuka ;r,hkays ÿi%dù;dj fjkia lsÍu l, yelsjkafka ;r,fhys wka;¾ wKql wdl¾IK n, fjkia lsÍfuks' ÿid%ù;dj iy tys Ndú;hk( a b;du;ua ir<j wêl nj óme‚ iy c,fha je.sÍfï b;du;a ir<j ÿi%dù;dj ixl,amh iy tys fhÿï i<ld ne,Sug fuu ,smsfha wruqK fõ' úúO l¾udka; j,§ ÿi%dù;dj jeo.;a ñKqula f,i Ndú;d flf¾' hï ;r,hla hdka;%slj m%jdykh lsÍfï§" ix>gl tlsfkl uqiq lsÍfï§" ksYamdokhl .=Kd;aul;dj ;SrKh lsÍfï§ jeks Wmfhda.S;djkays ÿi%dù;dj uekSu b;du;au jeo.;afõ' hï ix>gl ñY% lsÍfï§ ÿi%dù;dfjys isÿjk fjkia lï ms<sn|j oeäj ie,ls,su;a úh hq;=h' m<uqj ÿi%dù;dj hkq l=ulaoehs i<ld n,uq' ÿi%dù;dj hkq hï ;r,hl ksoyfia .,d hEug tfrysj mj;sk m%;sfrdaOh f,i ir<j w¾: olajd we;' fN!;sl úoHd;aulj ;r,hl ÿi%dù;dj foi n,kqfha tys wKq w;r wNHka;r >¾IKh fya;=fjka tu wka;¾ wKql .eàï iy meg,Sï ^cT,a,sisTkaia tkagkaggaÜia& we;s ùfuka isÿjk ixisoaêhla f,ih' fuksid ÿi%dù;dj wêl Wl= ;r,hla ;=, wKq .uka lsÍfï§ idfmalaIj by< Yla;shla jehfõ' (collisions and entanglements) (microscopic and macroscopic properties) wKqj, m%udKh iy yevh ;r,fhys ÿi%dù;dj flfrys n,mdk wdldrh by;§ idlÉPd lf,uq' úúO wdl,k øjH ^wâfjia& fh§fuka ;r,hkays ÿi%dù;dj fjkia lsÍu l, yelsjkafka ;r,fhys wka;¾ wKql wdl¾IK n, fjkia lsÍfuks' flaYkd,slduh ÿi%dù;dudkh (additives) (additives) December 2023 | Issue 01 20 Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01
ÿi%dù;dj yodrkafka ukaoehs i,ld n,uq' tkï" 1' ;r,hkays uQ,sl fN!;slh wjfndaO lr .ekSug 2' l¾udka; l%shdj,s m%Yia; lsÍug 3' wdrlaIs; f,i fhojqï isÿlsÍug 4' l¾udka; l%shdj,s j, Yla;sh jehùu wvq lr .ekSug 5' kj ksIamdok iy øjH ieliSug Institute of Physics Sri Lanka (IPSL) Physics Magazine | Volume 01 | Issue 01 ;r,hkays ufyalaISh .=K jk mSvkh iy WIaK;ajh fjkia lsÍfuka ÿi%dù;dj fjkia l, yels nj by;§ úia;r lf,uq' jHdlD;sl fõ.h ^fYa¾rfÜ ÿi%dù;dj i|yd n,mdk idOlhla nj y÷kdf.k we;' jHdlD;sl fõ.h hkq hï ;r,hla ia:r jYfhka we;ehs ie,l+ úg" tla tla ia:rhkays idfmalaI p,kfha fõ.hhs' tys tallh ;;amrhg f,i w¾: olajd we;' ;j;a jeo.;a ixl,amhla jkqfha jHdlD;sl wd;;shhs ^fYa¾ iag%fia&' th w¾: olajd we;af;a hï u;=msglg iam¾Ilhla f,i fhfok tall j¾.M,hlg fhfok n,hhs' fuu jHdlD;sl wd;;sfhka ;r,hkays ia:r w;r idfmalaIj p,khka we;s lrhs' fuu w¾: oelaùug wkqj ;r,hl ÿi%dù;dj hkq jHdlD;sl wd;;shg tfrysj mj;sk m%;sfrdaOh hs' m%Odk ÿi%dù;d wdldr folla we;' tkï .;sl ÿi%dù;dj ^âhakñc úiacTa& iy m%.;s ÿi%dù;dj ^lsfkc úiacTisÜha& hs' .;sl ÿi%dù;dj w¾:olajd we;af;a jHdlD;sl wd;;sh" jHdlD;sl fõ.hg orK wkqmd;h f,ih' .;sl ÿi%dù;dfjys tallh meial,a-;;a;amr ^M'ia& fyj;a fikaáfmdhsia ^cMa& kï tallfhka oelafõ' m%.;s ÿi%dù;dj w¾: olajd we;af;a .;sl ÿi%dù;dj g >K;ajh ork wkqmd;fhks' fuys tallh j¾. ógrhg ;;a;amr fõ' th iafg%dala ^SÜ& f,i oelafõ' ÿi%dù;dj ms,sn|j idlÉPd lsÍfï§ ie,ls,su;a jk wfkla jeo.;a ixl,amh jkafka ;r,hl we;sjk jHdj¾;hhs' jHdj¾;h hkq hï wlaIhla jgd N%uKh ùfï§ we;sjk N%uK n,hhs' ke;fyd;a ;r,hla ;=, boaola ^iamsâf,a N%uKh lsÍfïÈ tu ;r,fhys iajdNdúl j we;sjk m%;sfrdaOh j,lajd,Sug wjYH n,hhs' ksõfgdakshdkq ;r, iy ksõfgdakshdkq fkdjk ;r, .ek oeka i,ld n,uq' hï ;r,hl u; fhfok jHdlD;sl fõ.h ^fYa¾ rfÜ fjkia lsÍfï § ;r,fhys ÿi%dù;dj fkdfjkiaj mj;Skï tu ;r,h ksõfgdakshdkq ;r,hla f,i y÷kajkafkuq' jd;h" uoHidr iy c,h ksõfgdakshdkq ;r, j,g WodyrK fõ' ksõfgdakshdkq fkdjk ;r, j,g WodyrK f,i flpma" o;afnfy;a" reêrh" Ieïmq j¾. ie,lsh yel' ksõfgdakshdkq fkdjk ;r, u; fhfok jHdlD;sl fõ.h u; tys ÿi%dù;dj fjkia fõ' ksõfgdakshdkq fkdjk ;r,hkays we;sjk$ we;slrk jHdlD;sl wd;;sh ^fYa¾ iag%fa& hgf;a ;r,fhys yeisÍu wkqj m%Odk wdldr lsysmhlg fjka flf¾' tkï jHdlD;slj ;=kSjk ;r," jHdlD;slj Wl=jk ;r, iy ìka.ayeï iqúld¾h ;r, ^ôka>ï ma,iaác *a¨ia& f,ih' hï jHdlD;sl wd;;shla ;r,fhys fh§fuka ÿi%dù;dj wvq ùu" jeäùu iuyr ksõfgdakshdkq fkdjk ;r,hkays oelsh yel' ìka.ayeï iqúld¾h ;r,hkays wju jHdlD;sl wd;;shla fhoùfuka ;r,h myiqfjka p,kh l, yelsfõ' WodyrKhla f,i fufhdkSia iy o;a fnfy;a ie,lsh yel' (shear rate) (shear stress) (dynamic viscosity) (kinematic viscosity) (Pa.s) (cP) (St) (spindle) (shear rate) (shear stress) (Bingham plastic fluids) N%uK ÿi%dù;dudkh 1' ;r,hla flaYkd,sldjlska m%jdyhg ,la lsÍfuka uefkk ÿi%dù;dudk 2' ;r,hla ;=, boaola N%uKfhka uefkk ÿi%dù;dudk 3' ;r,hla ;=,ska f.da,hla jeàu u.ska uefkk ÿi%dù;dudk 4' ;r,h lïmkh lsÍfuka uefkk ÿi%dù;dudk ÿi%dù;dj wOHhkh lsÍug úúO l%ufõo Ndú;d flf¾' thska ,nd.kakd úúO ÿi%dù;djhka úúO Wmfhda.S;djhka i|yd jeäÿr wOHhkh flf¾' fuys§ i,lkq ,nk ;r,fhys ÿi%dù;d ñKqï j, ksrjoH;dj" ue‚h yels ÿi%dù;d mrdih" ukskq ,eìh hq;= WIaK;ajh jeks idOl ie,lSfuka mÍlaIK l%ufõoh f;dard .; hq;=fõ' ÿi%dù;d ñKqï jd¾;d lsÍfï§ ÿi%dù;dj u‚kq ,enQ WIaK;ajh oelaúh hq;=h' uQ,sl ÿi%dù;dudk lsysmhla i,ld n,uq' tla tla ÿi%dù;dudk ms<sn|j ;jÿrg;a i<ld n,uq' flaYkd,slduh ÿi%dù;dudkhka ys§ okakd ñKqï iys; flaYkd,sldjla ;=,ska ;r,hla .uka lsÍfï fõ.h ukskq ,efí' fuys§ ;r,fha tall mßudjla okakd ñkqï iys; flaYkd,sldjla ;=,ska m%jdyh ùug .;jk ld,h tys ÿi%dù;djg wkqf,dauj iudkqmd;sl fõ' flaYkd,slduh ÿi%dù;dudk" okakd ÿi%dù;djla iys; ;r,hla ^WodyrKhla f,i c,h& Ndú;fhka l%udxlkh flf¾' iafg%dala kshuh - Capillary viscometer - Rotational viscometer - Falling ball viscometer - Vibrational viscometer December 2023 | Issue 01 21
wdY%s; f,aLK Physics Magazine | Issue 01 | 123 N%uK ÿi%dù;dudk u.ska ÿi%dù;dj uekSfï§" ;r,h ;=, .s,ajQ boaola N%uKh lsÍug wjYH jk jHdj¾;h ukskq ,efí' fuys§ wod, ;r,fhys wjYH jk jHdj¾;h ^fgd¾Ca tys ÿi%dù;dj g wkqf,dauj iudkqmd;sl fõ' fujka ÿi%dù;dudk l%udxlkh i|yd iïu; ;r, Ndú;d flf¾' tfukau ;r,hg jvd >K;ajfhka jeä fnda,hla" ;r,h msÍ we;s is,skavrhla ;=,ska my,g jeàug hk ld,h uekSfuka ;r,fha ÿi%dù;dj ueksh yel' fï i|yd úrdu >áldjlska ksrjoH f,i ld,h ukskq ,efí' iafg%dalaia iólrKh wdY%fhka ÿi%dù;dj .Kkh flf¾' ÿi%dù ksõfgdakshdkq ;r,hla ;=, Bg jvd >K;ajfhka jeä f.da,hla .s,Su fyda ;r,h ;=, ;ekam;a ùu isÿjk wdldrh iafg%dala kshufhka i,ld n,hs' ;r,hg idfmalaIj >K;ajh jeä f.da,hla ;r,h ;=, .s,S hEug kï f.da,fhys W;ama,jl;dj" .=re;ajdl¾IK n,hg jvd jeäúh hq;=h' tfukau" ;r,h ;=, ;ekam;aùfï § my,g we;sjk iïm%hqla; n,h tys W;ama,ajl;djh iy ;ekam;aùfï n,h hk foflys wka;rfhka oelafõ' lïmk ÿi%dù;dudk u.ska ;r,hl ÿi%dù;dj uekSfï§ my; wdldrhg isÿflf¾' ndysrj ,ndfok lïmkhg tfrysj ;r,h ;=,ska isÿjk Yla;s W;ai¾ckh ^tfk¾.aha äiaismáa& u.ska ,ndÿka lïmk ixLHd;hg jk n,mEu lïmk ixfõolhla yryd uekSu ;=,ska ;r,fhys ÿi%dù;dj .Kkh lrhs' wdpd¾h Èfk;a tia iurúl%u fcHIaG m¾fhaIK ;dlaIK{" øjH ;dlaIK wxYh" ld¾ñl ;dlaIK wdh;kh" 363" fn!oaOdf,dal udj;" fld<U 07 fuys fhdod.kakd lïmk ixfõolh ;eá fyda oKavla wdldrhg we;s w;r" th okakd ixLHd;hlska lïmkh fõ' lïmkfha úia;drh iy ixLHd;h ukskq ,nk w;r" ixfõolfha p,s;fhka ÿi%dù;dj .Kkh flf¾' ÿi%dù;dj uekSu úoHd;aul mÍlaId yd m¾fhaIK i|yd w;HjYH ñKqula fõ' l¾udka;uh Wmfhda.S;d iy l%shdj,s i|yd úúO ÿi%dù;dudk Ndú;d flf¾' tkï f*daâ lma ÿi%dù;dudk" nqnq¿ ÿi%dù;dudk" fla;=-;eá ÿi%dù;dudk jeks úúOdldr iajrEmfhka ÿi%dù;dudk úúO l¾udka; j,§ Ndú;d flf¾' fuu flá ,smsfhka ÿi%dù;dj ms,sn| ixl,amh ir,j iy fláfhka ixjdohg ,la lsÍu t;rï myiq fkdjQ nj ie,l=j ukdh' tksid ÿi%dù;dj ixl,amh ;jÿrg;a wOHhkh lsÍug Tng wdrdOkd lrñ' (torque) (energy dissipation) 1. https://doi.org/10.1007/978-1-4419-6494-6_1 2. https://doi.org/10.1021/i160061a021 3.ASTM D 2170 4. www.sciencefacts.com
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