International Standard Book Number
The International Standard Book Number is a unique numeric commercial book identifier. An ISBN is assigned to each edition and variation of a book, for example, an e-book, a paperback and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, the method of assigning an ISBN is nation-based and varies from country to country, often depending on how large the publishing industry is within a country. The initial ISBN configuration of recognition was generated in 1967 based upon the 9-digit Standard Book Numbering created in 1966, the 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108. Occasionally, a book may appear without a printed ISBN if it is printed privately or the author does not follow the usual ISBN procedure, this can be rectified later. Another identifier, the International Standard Serial Number, identifies periodical publications such as magazines, the ISBN configuration of recognition was generated in 1967 in the United Kingdom by David Whitaker and in 1968 in the US by Emery Koltay.
The 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108, the United Kingdom continued to use the 9-digit SBN code until 1974. The ISO on-line facility only refers back to 1978, an SBN may be converted to an ISBN by prefixing the digit 0. For example, the edition of Mr. J. G. Reeder Returns, published by Hodder in 1965, has SBN340013818 -340 indicating the publisher,01381 their serial number. This can be converted to ISBN 0-340-01381-8, the check digit does not need to be re-calculated, since 1 January 2007, ISBNs have contained 13 digits, a format that is compatible with Bookland European Article Number EAN-13s. An ISBN is assigned to each edition and variation of a book, for example, an ebook, a paperback, and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, a 13-digit ISBN can be separated into its parts, and when this is done it is customary to separate the parts with hyphens or spaces.
Separating the parts of a 10-digit ISBN is done with either hyphens or spaces, figuring out how to correctly separate a given ISBN number is complicated, because most of the parts do not use a fixed number of digits. ISBN issuance is country-specific, in that ISBNs are issued by the ISBN registration agency that is responsible for country or territory regardless of the publication language. Some ISBN registration agencies are based in national libraries or within ministries of culture, in other cases, the ISBN registration service is provided by organisations such as bibliographic data providers that are not government funded. In Canada, ISBNs are issued at no cost with the purpose of encouraging Canadian culture. In the United Kingdom, United States, and some countries, where the service is provided by non-government-funded organisations. Australia, ISBNs are issued by the library services agency Thorpe-Bowker
Potentiometer (measuring instrument)
A potentiometer is an instrument for variable potential in a circuit. Before the introduction of the coil and digital volt meters, potentiometers were used in measuring voltage. The method was described by Johann Christian Poggendorff around 1841 and became a standard measuring technique. In this arrangement, a fraction of a voltage from a resistive slide wire is compared with an unknown voltage by means of a galvanometer. The sliding contact or wiper of the potentiometer is adjusted and the galvanometer briefly connected between the contact and the unknown voltage. The deflection of the galvanometer is observed and the sliding tap adjusted until the galvanometer no longer deflects from zero, at that point the galvanometer draws no current from the unknown source, and the magnitude of voltage can be calculated from the position of the sliding contact. This null balance measuring method is still important in electrical metrology, measurement potentiometers are divided into four main classes listed below.
Potentiometer is a device used to measure the EMF, TPD. It consists of a board where a tungsten or manganese wire is fitted on it and it works on the principle that the potential dropped between two points in a wire of uniform cross section is directly proportional to the distance between the points. Driving cell of some EMF which is greater than the EMF to be measured is used to send current through the circuit. It drops uniform potential along the potentiometer wire AB, between A and X, some potential is dropped. Consider the alternative path wire AGX for the flow of current in between A and X except the potentiometer wire, the potential due to driving cell is same for both AX segment of wire and the long wire AGX since they are in parallel. Thus, electric field exists along AGX, in this circuit, the ends of a uniform resistance wire R1 are connected to a regulated DC supply VS for use as a voltage divider. The supply voltage VS is adjusted until the galvanometer shows zero, an unknown DC voltage, in series with the galvanometer, is connected to the sliding wiper, across a variable-length section R3 of the resistance wire.
The wiper is moved until no current flows into or out of the source of unknown voltage, the voltage across the selected R3 section of wire is equal to the unknown voltage. The final step is to calculate the voltage from the fraction of the length of the resistance wire that was connected to the unknown voltage. The galvanometer does not need to be calibrated, as its function is to read zero or not zero. The unknown voltage can be calculated, V U = V S A X A B The constant resistance potentiometer is a variation of the idea in which a variable current is fed through a fixed resistor
William Thomson, 1st Baron Kelvin
William Thomson, 1st Baron Kelvin, OM, GCVO, PC, FRS, FRSE was a Scots-Irish mathematical physicist and engineer who was born in Belfast in 1824. He worked closely with mathematics professor Hugh Blackburn in his work and he had a career as an electric telegraph engineer and inventor, which propelled him into the public eye and ensured his wealth and honour. For his work on the telegraph project he was knighted in 1866 by Queen Victoria. He had extensive maritime interests and was most noted for his work on the mariners compass, absolute temperatures are stated in units of kelvin in his honour. He was ennobled in 1892 in recognition of his achievements in thermodynamics and he was the first British scientist to be elevated to the House of Lords. The title refers to the River Kelvin, which close by his laboratory at the University of Glasgow. His home was the red sandstone mansion Netherhall, in Largs. William Thomsons father, James Thomson, was a teacher of mathematics and engineering at Royal Belfast Academical Institution, James Thomson married Margaret Gardner in 1817 and, of their children, four boys and two girls survived infancy.
Margaret Thomson died in 1830 when William was six years old and his elder brother James were tutored at home by their father while the younger boys were tutored by their elder sisters. James was intended to benefit from the share of his fathers encouragement, affection. In 1832, his father was appointed professor of mathematics at Glasgow, the Thomson children were introduced to a broader cosmopolitan experience than their fathers rural upbringing, spending mid-1839 in London and the boys were tutored in French in Paris. Mid-1840 was spent in Germany and the Netherlands, language study was given a high priority. His sister, Anna Thomson, was the mother of James Thomson Bottomley FRSE, Thomson had heart problems and nearly died when he was 9 years old. In school, Thomson showed a keen interest in the classics along with his natural interest in the sciences, at the age of 12 he won a prize for translating Lucian of Samosatas Dialogues of the Gods from Latin to English. In the academic year 1839/1840, Thomson won the prize in astronomy for his Essay on the figure of the Earth which showed an early facility for mathematical analysis.
Throughout his life, he would work on the problems raised in the essay as a strategy during times of personal stress. On the title page of this essay Thomson wrote the lines from Alexander Popes Essay on Man. These lines inspired Thomson to understand the world using the power and method of science, Go
The simplest of these circuits are a form of rectifier which take an AC voltage as input and outputs a doubled DC voltage. The switching elements are simple diodes and they are driven to switch state merely by the voltage of the input. DC-to-DC voltage doublers cannot switch in this way and require a circuit to control the switching. They frequently require an element that can be controlled directly, such as a transistor. Voltage doublers are a variety of voltage multiplier circuit, but not all, voltage doubler circuits can be viewed as a single stage of a higher order multiplier, cascading identical stages together achieves a greater voltage multiplication. The Villard circuit, due to Paul Ulrich Villard, consists simply of a capacitor, while it has the great benefit of simplicity, its output has very poor ripple characteristics. Essentially, the circuit is a clamp circuit. The capacitor is charged on the negative half cycles to the peak AC voltage, the output is the superposition of the input AC waveform and the steady DC of the capacitor.
The effect of the circuit is to shift the DC value of the waveform, the negative peaks of the AC waveform are clamped to 0 V by the diode, therefore the positive peaks of the output waveform are 2Vpk. The peak-to-peak ripple is an enormous 2Vpk and cannot be smoothed unless the circuit is turned into one of the more sophisticated forms. This is the used to supply the negative high voltage for the magnetron in a microwave oven. The Greinacher voltage doubler is a significant improvement over the Villard circuit for a small cost in additional components. The ripple is reduced, nominally zero under open-circuit load conditions, but when current is being drawn depends on the resistance of the load. The circuit works by following a Villard cell stage with what is in essence a peak detector or envelope detector stage, the peak detector cell has the effect of removing most of the ripple while preserving the peak voltage at the output. The Greinacher circuit is commonly known as the half-wave voltage doubler.
He extended this idea into a cascade of multipliers in 1920 and this cascade of Greinacher cells is often inaccurately referred to as a Villard cascade. It is called a Cockcroft–Walton multiplier after the particle accelerator machine built by John Cockcroft and Ernest Walton, the concept in this topology can be extended to a voltage quadrupler circuit by using two Greinacher cells of opposite polarities driven from the same AC source. The output is taken across the two individual outputs, as with a bridge circuit, it is impossible to simultaneously ground the input and output of this circuit
Ionizing radiation is radiation that carries enough energy to free electrons from atoms or molecules, thereby ionizing them. Ionizing radiation is made up of energetic particles, ions or atoms moving at high speeds. The boundary between ionizing and non-ionizing electromagnetic radiation that occurs in the ultraviolet is not sharply defined, since different molecules, conventional definition places the boundary at a photon energy between 10 eV and 33 eV in the ultraviolet. Typical ionizing subatomic particles from radioactivity include alpha particles, beta particles, almost all products of radioactive decay are ionizing because the energy of radioactive decay is typically far higher than that required to ionize. Cosmic rays are generated by stars and certain events such as supernova explosions. Cosmic rays may produce radioisotopes on Earth, which in turn decay, cosmic rays and the decay of radioactive isotopes are the primary sources of natural ionizing radiation on Earth referred to as background radiation.
Ionizing radiation can be generated artificially using X-ray tubes, particle accelerators, ionizing radiation is invisible and not directly detectable by human senses, so radiation detection instruments such as Geiger counters are required to detect it. However, it can cause emission of light upon interaction with matter, such as in Cherenkov radiation. Exposure to ionizing radiation damage to living tissue, and can result in mutation, radiation sickness, cancer. Ionizing radiation is categorized by the nature of the particles or electromagnetic waves that create the ionizing effect and these have different ionization mechanisms, and may be grouped as directly or indirectly ionizing. Any charged massive particle can ionize atoms directly by fundamental interaction through the Coulomb force if it carries sufficient kinetic energy and this includes atomic nuclei, muons, charged pions and energetic charged nuclei stripped of their electrons. When moving at relativistic speeds these particles have enough energy to be ionizing.
For example, an alpha particle is ionizing, but moves at about 5% c. Natural cosmic rays are made up primarily of protons but include heavier atomic nuclei like helium ions. Pions can be produced in large amounts in particle accelerators, alpha particles consist of two protons and two neutrons bound together into a particle identical to a helium nucleus. Alpha particle emissions are produced in the process of alpha decay. Alpha particles are named after the first letter in the Greek alphabet, the symbol for the alpha particle is α or α2+. Because they are identical to helium nuclei, they are sometimes written as He2+ or 4 2He2+ indicating a Helium ion with a +2 charge
Physics is the natural science that involves the study of matter and its motion and behavior through space and time, along with related concepts such as energy and force. One of the most fundamental disciplines, the main goal of physics is to understand how the universe behaves. Physics is one of the oldest academic disciplines, perhaps the oldest through its inclusion of astronomy, Physics intersects with many interdisciplinary areas of research, such as biophysics and quantum chemistry, and the boundaries of physics are not rigidly defined. New ideas in physics often explain the mechanisms of other sciences while opening new avenues of research in areas such as mathematics. Physics makes significant contributions through advances in new technologies that arise from theoretical breakthroughs, the United Nations named 2005 the World Year of Physics. Astronomy is the oldest of the natural sciences, the stars and planets were often a target of worship, believed to represent their gods. While the explanations for these phenomena were often unscientific and lacking in evidence, according to Asger Aaboe, the origins of Western astronomy can be found in Mesopotamia, and all Western efforts in the exact sciences are descended from late Babylonian astronomy.
The most notable innovations were in the field of optics and vision, which came from the works of many scientists like Ibn Sahl, Al-Kindi, Ibn al-Haytham, Al-Farisi and Avicenna. The most notable work was The Book of Optics, written by Ibn Al-Haitham, in which he was not only the first to disprove the ancient Greek idea about vision, but came up with a new theory. In the book, he was the first to study the phenomenon of the pinhole camera, many European scholars and fellow polymaths, from Robert Grosseteste and Leonardo da Vinci to René Descartes, Johannes Kepler and Isaac Newton, were in his debt. Indeed, the influence of Ibn al-Haythams Optics ranks alongside that of Newtons work of the same title, the translation of The Book of Optics had a huge impact on Europe. From it, European scholars were able to build the devices as what Ibn al-Haytham did. From this, such important things as eyeglasses, magnifying glasses, Physics became a separate science when early modern Europeans used experimental and quantitative methods to discover what are now considered to be the laws of physics.
Newton developed calculus, the study of change, which provided new mathematical methods for solving physical problems. The discovery of new laws in thermodynamics and electromagnetics resulted from greater research efforts during the Industrial Revolution as energy needs increased, inaccuracies in classical mechanics for very small objects and very high velocities led to the development of modern physics in the 20th century. Modern physics began in the early 20th century with the work of Max Planck in quantum theory, both of these theories came about due to inaccuracies in classical mechanics in certain situations. Quantum mechanics would come to be pioneered by Werner Heisenberg, Erwin Schrödinger, from this early work, and work in related fields, the Standard Model of particle physics was derived. Areas of mathematics in general are important to this field, such as the study of probabilities, in many ways, physics stems from ancient Greek philosophy