Showing posts with label Science. Show all posts
Showing posts with label Science. Show all posts

Monday, January 6, 2014

India`s biggest aircraft carrier INS Vikramaditya reaches Indian Ocean

M_Id_443175_INS_Vikramaditya

The much-awaited and long-delayed India’s biggest aircraft carrier INS Vikramaditya after being acquired from Russia has finally arrived in the Arabian Sea after a long voyage. The $2.3 billion ship is currently being escorted by the ships of Indian Navy’s western fleet and is expected to reach the Kanwar base next week.
At the base weapons, sensors and MiG-29K fighter jets will integrated and the warship will become fully operational.
The carrier was purchased by India on 20 January 2004 after years of negotiations at a final price of $2.35 billion. The warship will be equipped with, as a part of the deal, 12 single-seat Mikoyan MiG-29K ‘Fulcrum-D’ and four dual-seat MiG-29KUB aircraft (with an option for 14 more aircraft), six Kamov Ka-31 “Helix” reconnaissance and anti-submarine helicopters, torpedo tubes, missile systems, and artillery units.
Indian Navy’s long term objective is to be able to respond to emergent situations far away from main land. After China’s ‘string of pearls’ theory, India needs to develop a grand strategy to counter the Chinese aggression in the Indian Ocean. INS Vikramaditya will have to play a crucial role in achieving this objective. During the three-month sea trials, the ship had demonstrated excellent seaworthiness, speed of 27.9 knots (about 52 km per hour) and manoeuvrability
History of the ship
Originally named Baku, the ship was launched in 1982, and commissioned in December 1987. After the collapse of the Soviet Union in 1991, the name of the ship was changed to Admiral Gorshkov. In 1994, an explosion in the boiler room forced the ship to be docked for a year for repair. It returned to service in 1995, she was finally withdrawn in 1996 and offered for sale.
Design
The most obvious design difference from the rest of the class is the massive planar array above the bridge. The biggest change to the weapon systems was the replacement of the SA-N-3 ‘Goblet’ and SA-N-4 ‘Gecko’ SAM launchers with four SA-N-9 ‘Gauntlet’ VLS launchers. This allowed room for another two SS-N-12 ‘Sandbox’ launchers. The air wing was the same as the other Kievs, consisting of a squadron of twelve Yak-38 ‘Forger’ V/STOL aircraft (until they were retired in 1992), twelve Ka-27 ‘Helix-A’ ASW/SAR helicopters and two Ka-31 ‘Helix’ AEW helicopters. Flight operations were assisted by the distinctive new Cake Stand TACAN.
The ship was used for trials of the Yak-141 Freestyle supersonic VTOL fighter.
To conclude, induction of INS Vikramaditya will significantly increase the overall effectiveness of the Indian Navy.

Scientists created sperm-based ‘biobots’ in Germany

Mirobio robot

Scientists led by Oliver Schmidt created the biological robots or biobots powered by sperm in the Institute for Integrative Nanosciences in Dresden, Germany on December 2013. It is also called as biohybrid micro-robot. The researchers created magnetic nanotubes that were 50 microns long by 5 to 8 microns in diameter and dropped these into a fluid containing bull sperm.
The tubes were narrower at one end to stop the sperm from escaping and can be rotated by using magnetic fields.
The tail-like flagellum of the sperm cell sticks outside the end of the tube and power the bibot like a propeller
Benefits
These “biobots” can be used to guide individual sperm or to deliver targeted doses of drugs or fertilizing an egg. Schmidt Said that sperm cells are an attractive option because they are harmless to the human body, do not require an external power source and swam through viscous liquids.
Till now researchers has only managed to persuade groups of cells to cooperate with the help of chemical gradients and magnetic fields.

Friday, September 27, 2013

Worlds important Intercontinental ballistic missiles (ICBM)

• Peacekeeper (10,000 km (6,200 mi)+) (USA)
• Minuteman (10,000+ km) (USA)
• R-36M2 (SS-18) (10,000+ km) (Soviet Union, Russia)
• UR-100N (SS-19) (10,000+ km) (Soviet Union, Russia)
• RT-2PM "Topol" (SS-25) (10,000+ km) (Soviet Union, Russia)
• RT-2UTTH "Topol M" (SS-27) (10,000+ km) (Russia)
• RS-24 "Yars" (SS-29) (10,000+ km) (Russia)
• Agni-V (5000-8000 km) (India)
• Agni-VI (10,000 km) (India, under development)
• DF-31 (10,000+ km) (China)
• DF-5 (10,000+ km) (China)
• DF-41 (10,000+ km) (China)
• Jericho III (4,800 to 11,500 km) (Israel)

Tuesday, April 16, 2013

Some naturally occurring acids


Vinegar - Acetic acid

Sour milk (Curd) - Lactic acid

Orange - Citric acid

Lemon - Citric acid

Tamarind - Tartaric acid

Ant sting - Methanoic acid

Tomato - Oxalic acid

Nettle sting - Methanoic acid

Saturday, February 23, 2013

Svante Arrhenius (1859-1927)

Arrhenius was born near Uppsala, Sweden. He presented his thesis, on the conductivities of electrolyte solutions, to the University of Uppsala in 1884. For the next five years he travelled extensively and visited a number of research centers in Europe. In 1895 he was appointed professor of physics at the newly formed University of Stockholm, serving its rector from 1897 to 1902. From 1905 until his death he was Director of physical chemistry at the Nobel Institute in Stockholm. He continued to work for many years on electrolytic solutions. In 1899 he discussed the temperature dependence of reaction rates on the basis of an equation, now usually known as Arrhenius equation. He worked in a variety of fields, and made important contributions to immunochemistry, cosmology, the origin of life, and the causes of ice age. He was the first to discuss the ‘green house effect’ calling by that name. He received Nobel Prize in Chemistry in 1903 for his theory of electrolytic dissociation and its use in the development of chemistry.

Michael Faraday (1791–1867)

Faraday was born near London into a family of very  limited means. At the age of 14 he was an apprentice to a kind bookbinder who allowed Faraday to read the books he was binding. Through a fortunate chance he became laboratory assistant to Davy, and during 1813-4, Faraday accompanied him to the Continent. During this trip he gained much from the experience of coming into contact with many of the leading scientists of the time. In 1825, he succeeded Davy as Director of the Royal Institution laboratories, and in 1833 he also became the first Fullerian Professor of Chemistry. Faraday’s first important work was on analytical chemistry. After 1821 much of his work was on electricity and magnetism and different electromagnetic phenomena. His ideas have led to the establishment of modern field theory. He discovered his two laws of electrolysis in 1834. Faraday was a very modest and kind hearted person. He declined all honours and avoided scientific controversies. He preferred to work alone and never had any assistant. He disseminated science in a variety of ways including his Friday evening discourses, which he founded at the Royal Institution. He has been very famous for his Christmas lecture on the ‘Chemical History of a Candle’. He published nearly 450 scientific papers.

Peter Debye

Peter Debye, the Dutch chemist received Nobel prize in 1936 for his work on X-ray diffraction and dipole moments. The magnitude of the dipole moment is given in Debye units in order to honour him.

Dmitri Ivanovich Mendeleev (1834-1907)

Dmitri Mendeleev was born in Tobalsk, Siberia in Russia. After his father’s death, the family moved to St. Petersburg. He received his Master’s degree in Chemistry in 1856 and the doctoral degree in 1865. He taught at the University of St.Petersburg where he was appointed Professor of General Chemistry in 1867. Preliminary work for his great textbook “Principles of Chemistry” led Mendeleev to propose the Periodic Law and to construct his Periodic Table of elements. At that time, the structure of atom was unknown and Mendeleev’s idea to consider that the properties of the elements were in someway related to their atomic masses was a very imaginative one. To place certain elements into the correct group from the point of view of their chemical properties, Mendeleev reversed the order of some pairs of elements and asserted that their atomic masses were incorrect. Mendeleev also had the foresight to leave gaps in the Periodic Table for elements unknown at that time and predict their properties from the trends that he observed among the properties of related elements. Mendeleev’s predictions were proved to be astonishingly correct when these elements were discovered later.

Mendeleev’s Periodic Law spurred several areas of research during the subsequent decades. The discovery of the first two noble gases helium and argon in 1890 suggested the possibility that there must be other similar elements to fill an entire family. This idea led Ramsay to his successful search for krypton and xenon. Work on the radioactive decay series for uranium and thorium in the early years of twentieth century was also guided by the Periodic Table.

Mendeleev was a versatile genius. He worked on many problems connected with Russia’s natural resources. He invented an accurate barometer. In 1890, he resigned from the Professorship. He was appointed as the Director of the Bureau of Weights and Measures. He continued to carry out important research work in many areas until his death in 1907.

Mendeleev’s name has been immortalized by naming the element with atomic number 101, as Mendelevium. This name was proposed by American scientist Glenn T. Seaborg, the discoverer of this element, “in recognition of the pioneering role of the great Russian Chemist who was the first to use the periodic system of elements to predict the chemical properties of undiscovered elements, a principle which has been the key to the discovery of nearly all the transuranium elements”.

Erwin Schrödinger (1887-1961)

Erwin Schrödinger, an Austrian physicist received his Ph.D. in theoretical physics from the University of Vienna in 1910. In 1927 Schrödinger succeeded Max Planck at the University of Berlin at Planck’s request. In 1933, Schrödinger left Berlin because of his opposition to Hitler and Nazi policies and returned to Austria in 1936. After the invasion of Austria by Germany, Schrödinger was forcibly removed from his professorship. He then moved to Dublin, Ireland where he remained for seventeen years. Schrödinger shared the Nobel Prize for Physics with P.A.M. Dirac in 1933.

Werner Heisenberg (1901 – 1976)

Werner Heisenberg (1901 – 1976) received his Ph.D. in physics from the University of Munich in 1923. He then spent a year working with Max Born at Gottingen and three years with Niels Bohr in Copenhagen. He was professor of physics at the University of Leipzig from 1927 to 1941. During World War II, Heisenberg was in charge of German research on the atomic bomb. After the war he was named director of Max Planck Institute for physics in Gottingen. He was also accomplished mountain climber. Heisenberg was awarded the Nobel Prize in Physics in 1932.

Max Planck (1858 – 1947)

Max Planck, a German physicist, received his Ph.D in theoretical physics from the University of Munich in 1879. In 1888, he was appointed Director of the Institute of Theoretical Physics at the University of Berlin. Planck was awarded the Nobel Prize in Physics in 1918 for his quantum theory. Planck also made significant contributions in thermodynamics and other areas of physics.

Definitions of the SI Base Units


Metre (m): The metre is the length of path travelled by light in vacuum during a time interval of 1/299 792 458 of a second.

Kilogram (kg): The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram.

Second (s): The second is the duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.

Ampere (A): The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 metre apart in vacuum, would produce between these conductors a force equal to 2 10 -7 Newton per metre of length.

Kelvin (K): The kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.

Mole (mol): The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon-12. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.

Candela (cd): The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 1012 hertz and that has a radiant intensity in that direction of (1/683) watt per steradian.

Friday, February 22, 2013

ERNST MAYR

Born on 5 July 1904, in Kempten, Germany, ERNST MAYR, the Harvard University evolutionary biologist who has been called ‘The Darwin of the 20th century’, was one of the 100 greatest scientists of all time. Mayr joined Harvard’s Faculty of Arts and Sciences in 1953 and retired in 1975, assuming the title Alexander Agassiz Professor of Zoology Emeritus. Throughout his nearly 80-year career, his research spanned ornithology, taxonomy, zoogeography, evolution, systematics, and the history and philosophy of biology. He almost single-handedly made the origin of species diversity the central question of evolutionary biology that it is today. He also pioneered the currently accepted definition of a biological species. Mayr was awarded the three prizes widely regarded as the triple crown of biology: the Balzan Prize in 1983, the International Prize for Biology in 1994, and the Crafoord Prize in 1999. Mayr died at the age of 100 in the year 2004.

Thursday, February 21, 2013

Application of Doppler effect


The change in frequency caused by a moving object due to Doppler effect is used to measure their velocities in diverse areas such as military, medical science, astrophysics, etc. It is also used by police to check over-speeding of vehicles. A sound wave or electromagnetic wave of known frequency is sent towards a moving object. Some part of the wave is reflected from the object and its frequency is detected by the monitoring station. This change in frequency is called Doppler shift.
It is used at airports to guide aircraft, and in the military to detect enemy aircraft. Astrophysicists use it to measure the velocities of stars.
Doctors use it to study heart beats and blood flow in different part of the body. Here they use ulltrasonic waves, and in common practice, it is called sonography. Ultrasonic waves enter the body of the person, some of them are reflected back, and give information about motion of blood and pulsation of heart valves, as well as pulsation of the heart of the foetus. In the case of heart, the picture generated is called echocardiogram.

Densities of some solids and liquids


Substance                                       Atomic Mass (u)                          Density (103 Kg m-3)

Carbon (diamond)                           12.01                                           2.22

Gold                                              197.00                                         19.32

Nitrogen (liquid)                              14.01                                           1.00

Lithium                                          6.94                                             0.53

Fluorine (liquid)                              19.00                                            1.14

Ludwig Boltzmann (1844 – 1906)

born in Vienna, Austria, worked on the kinetic theory of gases independently of Maxwell. A firm advocate of atomism, that is basic to kinetic theory, Boltzmann provided a statistical interpretation of the Second Law of thermodynamics and the concept of entropy. He is regarded as one of the founders of classical statistical mechanics. The proportionality constant connecting energy and temperature in kinetic theory is known as Boltzmann’s constant in his honour.

Wednesday, February 20, 2013

Amedeo Avogadro (1776 – 1856)

He made a brilliant guess that equal volumes of gases have equal number of molecules at the same temperature and pressure. This helped in understanding the combination of different gases in a very simple way. It is now called Avogadro’s hypothesis (or law). He also suggested that the smallest constituent of gases like hydrogen, oxygen and nitrogen are not atoms but diatomic molecules.

John Dalton (1766- 1844)

He was an English chemist. When different types of atoms combine, they obey certain simple laws. Dalton’s atomic theory explains these laws in a simple way. He also gave a theory of colour blindness.

Atomic Hypothesis in Ancient India and Greece


Though John Dalton is credited with the introduction of atomic viewpoint in modern science, scholars in ancient India and Greece conjectured long before the existence of atoms and molecules. In the Vaiseshika school of thought in India founded by Kanada (Sixth century B.C.) the atomic picture was developed in considerable detail. Atoms were thought to be eternal, indivisible, infinitesimal and ultimate parts of matter. It was argued that if matter could be subdivided without an end, there would be no difference between a mustard seed and the Meru mountain. The four kinds of atoms (Paramanu — Sanskrit word for the smallest particle) postulated were Bhoomi (Earth), Ap (water), Tejas (fire) and Vayu (air) that have characteristic mass and other attributes, were propounded. Akasa (space) was thought to have no atomic structure and was continuous and inert. Atoms combine to form different molecules (e.g. two atoms combine to form a diatomic molecule dvyanuka, three atoms form a tryanuka or a triatomic molecule), their properties depending upon the nature and ratio of the constituent atoms. The size of the atoms was also estimated, by conjecture or by methods that are not known to us. The estimates vary. In Lalitavistara, a famous biography of the Buddha written mainly in the second century B.C., the estimate is close to the modern estimate of atomic size, of the order of 10 –10 m.
In ancient Greece, Democritus (Fourth century B.C.) is best known for his atomic hypothesis. The word ‘atom’ means ‘indivisible’ in Greek. According to him, atoms differ from each other physically, in shape, size and other properties and this resulted in the different properties of the substances formed
by their combination. The atoms of water were smooth and round and unable to ‘hook’ on to each
other, which is why liquid /water flows easily. The atoms of earth were rough and jagged, so they held
together to form hard substances. The atoms of fire were thorny which is why it caused painful burns.
These fascinating ideas, despite their ingenuity, could not evolve much further, perhaps because they
were intuitive conjectures and speculations not tested and modified by quantitative experiments - the
hallmark of modern science.

Pioneers of Thermodynamics

Lord Kelvin (William Thomson) (1824-1907), born in Belfast, Ireland, is among the foremost British scientists of the nineteenth century. Thomson played a key role in the development of the law of conservation of energy suggested by the work of James Joule (1818-1889), Julius Mayer (1814- 1878) and Hermann Helmholtz (1821-1894). He collaborated with Joule on the so-called Joule-Thomson effect : cooling of a gas when it expands into vacuum. He introduced the notion of the absolute zero of temperature and proposed the absolute temperature scale, now called the Kelvin scale in his honour. From the work of Sadi Carnot (1796-1832), Thomson arrived at a form of the Second Law of Thermodynamics. Thomson was a versatile physicist, with notable contributions to electromagnetic theory and hydrodynamics.


Rudolf Clausius (1822-1888), born in Poland, is generally regarded as the discoverer of the Second Law of Thermodynamics. Based on the work of Carnot and Thomson, Clausius arrived at the important notion of entropy that led him to a fundamental version of the Second Law of Thermodynamics that states that the entropy of an isolated system can never decrease. Clausius also worked on the kinetic theory of gases and obtained the first reliable estimates of molecular size, speed, mean free path, etc.