Morse code is a character encoding scheme used in telecommunication that encodes text characters as standardized sequences of two different signal durations called dots and dashes or dits and dahs. Morse code is named for Samuel F. B. Morse, an inventor of the telegraph; the International Morse Code encodes the 26 English letters A through Z, some non-English letters, the Arabic numerals and a small set of punctuation and procedural signals. There is no distinction between lower case letters; each Morse code symbol is formed by a sequence of dashes. The dot duration is the basic unit of time measurement in Morse code transmission; the duration of a dash is three times the duration of a dot. Each dot or dash within a character is followed by period of signal absence, called a space, equal to the dot duration; the letters of a word are separated by a space of duration equal to three dots, the words are separated by a space equal to seven dots. To increase the efficiency of encoding, Morse code was designed so that the length of each symbol is inverse to the frequency of occurrence in text of the English language character that it represents.
Thus the most common letter in English, the letter "E", has the shortest code: a single dot. Because the Morse code elements are specified by proportion rather than specific time durations, the code is transmitted at the highest rate that the receiver is capable of decoding; the Morse code transmission rate is specified in groups per minute referred to as words per minute. Morse code is transmitted by on-off keying of an information carrying medium such as electric current, radio waves, visible light or sound waves; the current or wave is present during time period of the dot or dash and absent during the time between dots and dashes. Morse code can be memorized, Morse code signalling in a form perceptible to the human senses, such as sound waves or visible light, can be directly interpreted by persons trained in the skill; because many non-English natural languages use other than the 26 Roman letters, Morse alphabets have been developed for those languages. In an emergency, Morse code can be generated by improvised methods such as turning a light on and off, tapping on an object or sounding a horn or whistle, making it one of the simplest and most versatile methods of telecommunication.
The most common distress signal is SOS – three dots, three dashes, three dots – internationally recognized by treaty. Early in the nineteenth century, European experimenters made progress with electrical signaling systems, using a variety of techniques including static electricity and electricity from Voltaic piles producing electrochemical and electromagnetic changes; these numerous ingenious experimental designs were precursors to practical telegraphic applications. Following the discovery of electromagnetism by Hans Christian Ørsted in 1820 and the invention of the electromagnet by William Sturgeon in 1824, there were developments in electromagnetic telegraphy in Europe and America. Pulses of electric current were sent along wires to control an electromagnet in the receiving instrument. Many of the earliest telegraph systems used a single-needle system which gave a simple and robust instrument. However, it was slow, as the receiving operator had to alternate between looking at the needle and writing down the message.
In Morse code, a deflection of the needle to the left corresponded to a dot and a deflection to the right to a dash. By making the two clicks sound different with one ivory and one metal stop, the single needle device became an audible instrument, which led in turn to the Double Plate Sounder System; the American artist Samuel F. B. Morse, the American physicist Joseph Henry, Alfred Vail developed an electrical telegraph system, it needed a method to transmit natural language using only electrical pulses and the silence between them. Around 1837, therefore, developed an early forerunner to the modern International Morse code. William Cooke and Charles Wheatstone in England developed an electrical telegraph that used electromagnets in its receivers, they obtained an English patent in June 1837 and demonstrated it on the London and Birmingham Railway, making it the first commercial telegraph. Carl Friedrich Gauss and Wilhelm Eduard Weber as well as Carl August von Steinheil used codes with varying word lengths for their telegraphs.
In 1841, Cooke and Wheatstone built a telegraph that printed the letters from a wheel of typefaces struck by a hammer. The Morse system for telegraphy, first used in about 1844, was designed to make indentations on a paper tape when electric currents were received. Morse's original telegraph receiver used a mechanical clockwork to move a paper tape; when an electrical current was received, an electromagnet engaged an armature that pushed a stylus onto the moving paper tape, making an indentation on the tape. When the current was interrupted, a spring retracted the stylus and that portion of the moving tape remained unmarked. Morse code was developed so that operators could translate the indentations marked on the paper tape into text messages. In his earliest code, Morse had planned to transmit only numerals and to use a codebook to look up each word according to the number, sent. However, the code was soon expanded by Alfred Vail in 1840 to include letters and special characters so it could be used more generally.
Vail estimated the frequency of use of letters in the English language by counting the movable type he found in the type-cases of a local newspaper in Morristown. The shorter marks were called "dots" and the longer ones "dashes", the letters most used were assigned the shorter sequences of dots and dashes; this code was used since 1844 and became known as Morse lan
The Amalfian Laws are a code of maritime laws compiled in the 12th century in Amalfi, a town in Italy. They took the form of the Tabula Amalfitana, were for centuries the international mercantile code accepted and taken as a model
International System of Units
The International System of Units is the modern form of the metric system, is the most used system of measurement. It comprises a coherent system of units of measurement built on seven base units, which are the ampere, second, kilogram, mole, a set of twenty prefixes to the unit names and unit symbols that may be used when specifying multiples and fractions of the units; the system specifies names for 22 derived units, such as lumen and watt, for other common physical quantities. The base units are derived from invariant constants of nature, such as the speed of light in vacuum and the triple point of water, which can be observed and measured with great accuracy, one physical artefact; the artefact is the international prototype kilogram, certified in 1889, consisting of a cylinder of platinum-iridium, which nominally has the same mass as one litre of water at the freezing point. Its stability has been a matter of significant concern, culminating in a revision of the definition of the base units in terms of constants of nature, scheduled to be put into effect on 20 May 2019.
Derived units may be defined in terms of other derived units. They are adopted to facilitate measurement of diverse quantities; the SI is intended to be an evolving system. The most recent derived unit, the katal, was defined in 1999; the reliability of the SI depends not only on the precise measurement of standards for the base units in terms of various physical constants of nature, but on precise definition of those constants. The set of underlying constants is modified as more stable constants are found, or may be more measured. For example, in 1983 the metre was redefined as the distance that light propagates in vacuum in a given fraction of a second, thus making the value of the speed of light in terms of the defined units exact; the motivation for the development of the SI was the diversity of units that had sprung up within the centimetre–gram–second systems and the lack of coordination between the various disciplines that used them. The General Conference on Weights and Measures, established by the Metre Convention of 1875, brought together many international organisations to establish the definitions and standards of a new system and standardise the rules for writing and presenting measurements.
The system was published in 1960 as a result of an initiative that began in 1948. It is based on the metre–kilogram–second system of units rather than any variant of the CGS. Since the SI has been adopted by all countries except the United States and Myanmar; the International System of Units consists of a set of base units, derived units, a set of decimal-based multipliers that are used as prefixes. The units, excluding prefixed units, form a coherent system of units, based on a system of quantities in such a way that the equations between the numerical values expressed in coherent units have the same form, including numerical factors, as the corresponding equations between the quantities. For example, 1 N = 1 kg × 1 m/s2 says that one newton is the force required to accelerate a mass of one kilogram at one metre per second squared, as related through the principle of coherence to the equation relating the corresponding quantities: F = m × a. Derived units apply to derived quantities, which may by definition be expressed in terms of base quantities, thus are not independent.
Other useful derived quantities can be specified in terms of the SI base and derived units that have no named units in the SI system, such as acceleration, defined in SI units as m/s2. The SI base units are the building blocks of the system and all the other units are derived from them; when Maxwell first introduced the concept of a coherent system, he identified three quantities that could be used as base units: mass and time. Giorgi identified the need for an electrical base unit, for which the unit of electric current was chosen for SI. Another three base units were added later; the early metric systems defined a unit of weight as a base unit, while the SI defines an analogous unit of mass. In everyday use, these are interchangeable, but in scientific contexts the difference matters. Mass the inertial mass, represents a quantity of matter, it relates the acceleration of a body to the applied force via Newton's law, F = m × a: force equals mass times acceleration. A force of 1 N applied to a mass of 1 kg will accelerate it at 1 m/s2.
This is true whether the object is floating in space or in a gravity field e.g. at the Earth's surface. Weight is the force exerted on a body by a gravitational field, hence its weight depends on the strength of the gravitational field. Weight of a 1 kg mass at the Earth's surface is m × g. Since the acceleration due to gravity is local and varies by location and altitude on the Earth, weight is unsuitable for precision
Lebanon known as the Lebanese Republic, is a country in Western Asia. It is bordered by Syria to the north and east and Israel to the south, while Cyprus is west across the Mediterranean Sea. Lebanon's location at the crossroads of the Mediterranean Basin and the Arabian hinterland facilitated its rich history and shaped a cultural identity of religious and ethnic diversity. At just 10,452 km2, it is the smallest recognized sovereign state on the mainland Asian continent; the earliest evidence of civilization in Lebanon dates back more than seven thousand years, predating recorded history. Lebanon was the home of the Canaanites/Phoenicians and their kingdoms, a maritime culture that flourished for over a thousand years. In 64 BC, the region came under the rule of the Roman Empire, became one of the Empire's leading centers of Christianity. In the Mount Lebanon range a monastic tradition known as the Maronite Church was established; as the Arab Muslims conquered the region, the Maronites held onto their identity.
However, a new religious group, the Druze, established themselves in Mount Lebanon as well, generating a religious divide that has lasted for centuries. During the Crusades, the Maronites re-established contact with the Roman Catholic Church and asserted their communion with Rome; the ties they established with the Latins have influenced the region into the modern era. The region was ruled by the Ottoman Empire from 1516 to 1918. Following the collapse of the empire after World War I, the five provinces that constitute modern Lebanon came under the French Mandate of Lebanon; the French expanded the borders of the Mount Lebanon Governorate, populated by Maronites and Druze, to include more Muslims. Lebanon gained independence in 1943, establishing confessionalism, a unique, Consociationalism-type of political system with a power-sharing mechanism based on religious communities. Bechara El Khoury, President of Lebanon during the independence, Riad El-Solh, first Lebanese prime minister and Emir Majid Arslan II, first Lebanese minister of defence, are considered the founders of the modern Republic of Lebanon and are national heroes for having led the country's independence.
Foreign troops withdrew from Lebanon on 31 December 1946, although the country was subjected to military occupations by Syria that lasted nearly thirty years before being withdrawn in April 2005 as well as the Israeli military in Southern Lebanon for fifteen years. Despite its small size, the country has developed a well-known culture and has been influential in the Arab world, powered by its large diaspora. Before the Lebanese Civil War, the country experienced a period of relative calm and renowned prosperity, driven by tourism, agriculture and banking; because of its financial power and diversity in its heyday, Lebanon was referred to as the "Switzerland of the East" during the 1960s, its capital, attracted so many tourists that it was known as "the Paris of the Middle East". At the end of the war, there were extensive efforts to revive the economy and rebuild national infrastructure. In spite of these troubles, Lebanon has the 7th highest Human Development Index and GDP per capita in the Arab world after the oil-rich economies of the Persian Gulf.
Lebanon has been a member of the United Nations since its founding in 1945 as well as of the Arab League, the Non-Aligned Movement, Organisation of the Islamic Cooperation and the Organisation internationale de la francophonie. The name of Mount Lebanon originates from the Phoenician root lbn meaning "white" from its snow-capped peaks. Occurrences of the name have been found in different Middle Bronze Age texts from the library of Ebla, three of the twelve tablets of the Epic of Gilgamesh; the name is recorded in Ancient Egyptian as Rmnn, where R stood for Canaanite L. The name occurs nearly 70 times in the Hebrew Bible, as לְבָנוֹן. Lebanon as the name of an administrative unit was introduced with the Ottoman reforms of 1861, as the Mount Lebanon Mutasarrifate, continued in the name of the State of Greater Lebanon in 1920, in the name of the sovereign Republic of Lebanon upon its independence in 1943; the borders of contemporary Lebanon are a product of the Treaty of Sèvres of 1920. Its territory was the core of the Bronze Age Phoenician city-states.
As part of the Levant, it was part of numerous succeeding empires throughout ancient history, including the Egyptian, Babylonian, Achaemenid Persian, Hellenistic and Sasanid Persian empires. After the 7th-century Muslim conquest of the Levant, it was part of the Rashidun, Abbasid Seljuk and Fatimid empires; the crusader state of the County of Tripoli, founded by Raymond IV of Toulouse in 1102, encompassed most of present-day Lebanon, falling to the Mamluk Sultanate in 1289 and to the Ottoman Empire in 1517. With the dissolution of the Ottoman Empire, Greater Lebanon fell under French mandate in 1920, gained independence under president Bechara El Khoury in 1943. Lebanon's history since independence has been marked by alternating periods of political stability and prosperity based on Beirut's position as a regional center for finance and trade, interspersed with political turmoil and
RMS Titanic was a British passenger liner that sank in the North Atlantic Ocean in 1912, after colliding with an iceberg during her maiden voyage from Southampton to New York City. Of the estimated 2,224 passengers and crew aboard, more than 1,500 died, making it one of modern history's deadliest commercial marine disasters during peacetime. RMS Titanic was the largest ship afloat at the time she entered service and was the second of three Olympic-class ocean liners operated by the White Star Line, she was built by the Wolff shipyard in Belfast. Thomas Andrews, chief naval architect of the shipyard at the time, died in the disaster. Titanic was under the command of Capt. Edward Smith, who went down with the ship; the ocean liner carried some of the wealthiest people in the world, as well as hundreds of emigrants from Great Britain and Ireland and elsewhere throughout Europe who were seeking a new life in the United States. The first-class accommodation was designed to be the pinnacle of comfort and luxury, with an on-board gymnasium, swimming pool, high-class restaurants and opulent cabins.
A high-powered radiotelegraph transmitter was available for sending passenger "marconigrams" and for the ship's operational use. Although Titanic had advanced safety features such as watertight compartments and remotely activated watertight doors, it only carried enough lifeboats for 1,178 people—about half the number on board, one third of her total capacity—due to outdated maritime safety regulations; the ship carried 16 lifeboat davits. However, Titanic carried only a total of 20 lifeboats, four of which were collapsible and proved hard to launch during the sinking. After leaving Southampton on 10 April 1912, Titanic called at Cherbourg in France and Queenstown in Ireland before heading west to New York. On 14 April, four days into the crossing and about 375 miles south of Newfoundland, she hit an iceberg at 11:40 p.m. ship's time. The collision caused the hull plates to buckle inwards along her starboard side and opened five of her sixteen watertight compartments to the sea. Meanwhile and some crew members were evacuated in lifeboats, many of which were launched only loaded.
A disproportionate number of men were left aboard because of a "women and children first" protocol for loading lifeboats. At 2:20 a.m. she foundered with well over one thousand people still aboard. Just under two hours after Titanic sank, the Cunard liner RMS Carpathia arrived and brought aboard an estimated 705 survivors; the disaster was met with worldwide shock and outrage at the huge loss of life and the regulatory and operational failures that led to it. Public inquiries in Britain and the United States led to major improvements in maritime safety. One of their most important legacies was the establishment in 1914 of the International Convention for the Safety of Life at Sea, which still governs maritime safety. Additionally, several new wireless regulations were passed around the world in an effort to learn from the many missteps in wireless communications—which could have saved many more passengers; the wreck of Titanic was discovered in 1985 during a US military mission, it remains on the seabed.
The ship was split in two and is disintegrating at a depth of 12,415 feet. Thousands of artefacts have been displayed at museums around the world. Titanic has become one of the most famous ships in history. Titanic is the second largest ocean liner wreck in the world, only beaten by her sister HMHS Britannic, the largest sunk, although she holds the record as the largest sunk while in service as a liner due to Britannic being used as a hospital ship at the time of her sinking; the final survivor of the sinking, Millvina Dean, aged two months at the time, died in 2009 at the age of 97. The name Titanic derives from the Titan of Greek mythology. Built in Belfast, Ireland, in the United Kingdom of Great Britain and Ireland, the RMS Titanic was the second of the three Olympic-class ocean liners—the first was the RMS Olympic and the third was the HMHS Britannic. Britannic was to be called Gigantic and was to be over 1,000 feet long, they were by far the largest vessels of the British shipping company White Star Line's fleet, which comprised 29 steamers and tenders in 1912.
The three ships had their genesis in a discussion in mid-1907 between the White Star Line's chairman, J. Bruce Ismay, the American financier J. P. Morgan, who controlled the White Star Line's parent corporation, the International Mercantile Marine Co.. The White Star Line faced an increasing challenge from its main rivals Cunard, which had launched the Lusitania and the Mauretania—the fastest passenger ships in service—and the German lines Hamburg America and Norddeutscher Lloyd. Ismay preferred to compete on size rather than speed and proposed to commission a new class of liners that would be larger than anything that had gone before as well as being the last word in comfort and luxury; the company sought an upgrade in their fleet in response to the Cunard giants but to replace their oldest pair of passenger ships still in service, being the SS Teutonic of 1889 and SS Majestic of 1890. Teutonic was replaced by Olympic. Majestic would be brought back into her old spot on White Star's New York service after Titanic's loss.
The ships were constructed by the Belfast shipbuilders Harland and Wolff, who had a long-established relati
The law of general average is a principle of maritime law whereby all stakeholders in a sea venture proportionally share any losses resulting from a voluntary sacrifice of part of the ship or cargo to save the whole in an emergency. For instance, should the crew jettison some cargo overboard to lighten the ship in a storm, the loss would be shared pro rata by both the carrier and the cargo-owners. In the exigencies of hazards faced at sea, crew members may have little time in which to determine whose cargo they are jettisoning. Thus, to avoid quarreling that could waste valuable time, there arose the equitable practice whereby all the merchants whose cargo landed safely would be called on to contribute a portion, based upon a share or percentage, to the merchant or merchants whose goods had been tossed overboard to avert imminent peril. General average traces its origins in ancient maritime law, the principle remains within the admiralty law of most countries. A form of what is now called general average was included in the Lex Rhodia, the Rhodes Maritime Code of circa 800 BC.
Julius Paulus Prudentissimus quoted from the law around the turn of the 3rd century, these quotes are preserved, an excerpt is included in Justinian's 6th-century Digest of Justinian, although the Lex Rhodia is itself now lost. After the fall of Rome, formal maritime law fell into disuse in Europe, although informal arrangements similar to the basic concept of general average was often followed as a practical matter; the medieval Rolls of Oléron a collection of judgments from a court in Bordeaux, provided guidance on what is now called general average, was taken as authoritative in many parts of Europe: the Laws of Wisbuy, as well as laws of Flanders, the Hanseatic League, Amsterdam and Catalonia, appear to have been copied from the Rolls of Oléron. An ordinance published by King Louis XIV of France in 1681 influenced laws in the rest of Europe, with the definition used in the French code followed in similar terms in codes and ordinances promulgated in that century and the next in Hamburg, Denmark, Spain, Amsterdam and Middelburg.
The first codification of general average was the York Antwerp Rules of 1890. American companies accepted it in 1949. General average requires three elements which are stated by Justice Grier in Barnard v. Adams: "1st. A common danger: a danger in which vessel and crew all participate. There must be a voluntary jettison, jactus, or casting away, of some portion of the joint concern for the purpose of avoiding this imminent peril, periculi imminentis evitandi causa, or, in other words, a transfer of the peril from the whole to a particular portion of the whole.""3rd. This attempt to avoid the imminent common peril must be successful"; the York-Antwerp Rules remain in effect, having been modified and updated several times since their 1890 introduction. The York Antwerp Rules were updated in 1994 and 2004; the text of the 1994 Rules may be found here: A summary of the 2004 changes may be found here. Despite advances in maritime transport technology, General Average continues on occasion to be invoked: The MV Hyundai Fortune declared general average following an explosion and fire in 2006 off the coast of Yemen.
The M/V MSC Sabrina declared general average in effect after grounding in the Saint Lawrence river on 8 March 2008. The owners of the Hanjin Osaka declared general average following an explosion in the ship's engine room on 8 January 2012. Maersk declared general average for Maersk Honam after a fire in the Arabian Sea in March 2018. Cornah, Richard. Cooke, Julian, ed. Lowndes & Rudolf: The Law of General Average and the York-Antwerp Rules. Sweet & Maxwel. ISBN 978-0414028463. Rose, Francis. General Average: Law and Practice. Maritime and Transport Law Library. Informa Law. ISBN 978-1843114185. Grime, Robert. Shipping Law. Concise College Texts. Sweet & Maxwell. ISBN 0 421 21130X. Baughan, Simon. Shipping Law. Routledge. ISBN 978 0 415 71219 4. Mandaraka-Shephard, Aleka. Maritime Law. Routledge. Definition of General Average, Duhaime's Law Dictionary Carver, Thomas Gilbert. "Average". In Chisholm, Hugh. Encyclopædia Britannica. 3. Cambridge University Press
World War I
World War I known as the First World War or the Great War, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. Contemporaneously described as "the war to end all wars", it led to the mobilisation of more than 70 million military personnel, including 60 million Europeans, making it one of the largest wars in history, it is one of the deadliest conflicts in history, with an estimated nine million combatants and seven million civilian deaths as a direct result of the war, while resulting genocides and the 1918 influenza pandemic caused another 50 to 100 million deaths worldwide. On 28 June 1914, Gavrilo Princip, a Bosnian Serb Yugoslav nationalist, assassinated the Austro-Hungarian heir Archduke Franz Ferdinand in Sarajevo, leading to the July Crisis. In response, on 23 July Austria-Hungary issued an ultimatum to Serbia. Serbia's reply failed to satisfy the Austrians, the two moved to a war footing. A network of interlocking alliances enlarged the crisis from a bilateral issue in the Balkans to one involving most of Europe.
By July 1914, the great powers of Europe were divided into two coalitions: the Triple Entente—consisting of France and Britain—and the Triple Alliance of Germany, Austria-Hungary and Italy. Russia felt it necessary to back Serbia and, after Austria-Hungary shelled the Serbian capital of Belgrade on the 28th, partial mobilisation was approved. General Russian mobilisation was announced on the evening of 30 July; when Russia failed to comply, Germany declared war on 1 August in support of Austria-Hungary, with Austria-Hungary following suit on 6th. German strategy for a war on two fronts against France and Russia was to concentrate the bulk of its army in the West to defeat France within four weeks shift forces to the East before Russia could mobilise. On 2 August, Germany demanded free passage through Belgium, an essential element in achieving a quick victory over France; when this was refused, German forces invaded Belgium on 3 August and declared war on France the same day. On 12 August and France declared war on Austria-Hungary.
In November 1914, the Ottoman Empire entered the war on the side of the Alliance, opening fronts in the Caucasus and the Sinai Peninsula. The war was fought in and drew upon each power's colonial empire as well, spreading the conflict to Africa and across the globe; the Entente and its allies would become known as the Allied Powers, while the grouping of Austria-Hungary and their allies would become known as the Central Powers. The German advance into France was halted at the Battle of the Marne and by the end of 1914, the Western Front settled into a battle of attrition, marked by a long series of trench lines that changed little until 1917. In 1915, Italy opened a front in the Alps. Bulgaria joined the Central Powers in 1915 and Greece joined the Allies in 1917, expanding the war in the Balkans; the United States remained neutral, although by doing nothing to prevent the Allies from procuring American supplies whilst the Allied blockade prevented the Germans from doing the same the U. S. became an important supplier of war material to the Allies.
After the sinking of American merchant ships by German submarines, the revelation that the Germans were trying to incite Mexico to make war on the United States, the U. S. declared war on Germany on 6 April 1917. Trained American forces would not begin arriving at the front in large numbers until mid-1918, but the American Expeditionary Force would reach some two million troops. Though Serbia was defeated in 1915, Romania joined the Allied Powers in 1916 only to be defeated in 1917, none of the great powers were knocked out of the war until 1918; the 1917 February Revolution in Russia replaced the Tsarist autocracy with the Provisional Government, but continuing discontent at the cost of the war led to the October Revolution, the creation of the Soviet Socialist Republic, the signing of the Treaty of Brest-Litovsk by the new government in March 1918, ending Russia's involvement in the war. This allowed the transfer of large numbers of German troops from the East to the Western Front, resulting in the German March 1918 Offensive.
This offensive was successful, but the Allies rallied and drove the Germans back in their Hundred Days Offensive. Bulgaria was the first Central Power to sign an armistice—the Armistice of Salonica on 29 September 1918. On 30 October, the Ottoman Empire capitulated. On 4 November, the Austro-Hungarian empire agreed to the Armistice of Villa Giusti after being decisively defeated by Italy in the Battle of Vittorio Veneto. With its allies defeated, revolution at home, the military no longer willing to fight, Kaiser Wilhelm abdicated on 9 November and Germany signed an armistice on 11 November 1918. World War I was a significant turning point in the political, cultural and social climate of the world; the war and its immediate aftermath sparked numerous uprisings. The Big Four (Britain, the United States, It