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Saturday, October 29, 2022

Political warfare

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Political_warfare

Statue of Sun Tzu in Yurihama, Tottori, Japan. Sun Tzu (544–498 BC), a military strategist, wrote of the superior power of political warfare in battle.

Political warfare is the use of political means to compel an opponent to do one's will, based on hostile intent. The term political describes the calculated interaction between a government and a target audience, including another state's government, military, and/or general population. Governments use a variety of techniques to coerce certain actions, thereby gaining relative advantage over an opponent. The techniques include propaganda and psychological operations ("PsyOps"), which service national and military objectives respectively. Propaganda has many aspects and a hostile and coercive political purpose. Psychological operations are for strategic and tactical military objectives and may be intended for hostile military and civilian populations.

Political warfare's coercive nature leads to weakening or destroying an opponent's political, social, or societal will, and forcing a course of action favorable to a state's interest. Political war may be combined with violence, economic pressure, subversion, and diplomacy, but its chief aspect is "the use of words, images and ideas". The creation, deployment, and continuation of these coercive methods are a function of statecraft for nations and serve as a potential substitute for more direct military action. For instance, methods like economic sanctions or embargoes are intended to inflict the necessary economic damage to force political change. The utilized methods and techniques in political war depend on the state's political vision and composition. Conduct will differ according to whether the state is totalitarian, authoritative, or democratic.

The ultimate goal of political warfare is to alter an opponent's opinions and actions in favour of one state's interests without utilizing military power. This type of organized persuasion or coercion also has the practical purpose of saving lives through eschewing the use of violence in order to further political goals. Thus, political warfare also involves "the art of heartening friends and disheartening enemies, of gaining help for one's cause and causing the abandonment of the enemies'". Generally, political warfare is distinguished by its hostile intent and through potential escalation; but the loss of life is an accepted consequence.

Tools

Peaceful

Political warfare utilizes all instruments short of war available to a nation to achieve its national objectives. The best tool of political warfare is "effective policy forcefully explained", or more directly, "overt policy forcefully backed". But political warfare is used, as one leading thinker on the topic has explained, "when public relations statements and gentle, public diplomacy-style persuasion – the policies of 'soft power' – fail to win the needed sentiments and actions" around the world. The major way political warfare is waged is through propaganda. The essence of these operations can be either overt or covert. "White" or overt propaganda comes from a known source. "Gray" propaganda, on the other hand, is the "semiofficial amplification of a government's voice". Radio Free Europe and Radio Liberty are examples of "gray" propaganda during the Cold War. "Black" propaganda, however, is propaganda which originates from an unknown source. The key to black propaganda is the fact that it most often "appears to come from a disinterested source when in fact it does not".

There are channels which can be used to transmit propaganda. Sophisticated use of technology allows an organization to disseminate information to a vast number of people. The most basic channel is the spoken word. This can include live speeches or radio and television broadcasts. Overt or covert radio broadcasting can be an especially useful tool. The printed word is also very powerful, including pamphlets, leaflets, books, magazines, political cartoons, and planted newspaper articles (clandestine or otherwise). Subversion, agents of influence, spies, journalists, and "useful idiots" can all be used as powerful tools in political warfare.

Aggressive

Soviet expansion: Formation of the Eastern Bloc

Political warfare also includes aggressive activities by one actor to offensively gain relative advantage or control over another. Between nation states, it can end in the seizure of power or in the open assimilation of the victimized state into the political system or power complex of the aggressor. This aggressor-victim relationship has also been seen between rivals within a state and may involve tactics like assassination, paramilitary activity, sabotage, coup d'état, insurgency, revolution, guerrilla warfare, and civil war.

  • Foreign infiltration or liberation occurs when a government is overthrown by foreign military or diplomatic intervention, or through covert means. The campaign's ultimate purpose is to gain control over another nation's political and social structure. The campaign could be led by the aggressor's national forces or by a political faction favorable to the aggressor within the other state. Paul M. Blackstock describes three stages involved in the extension of control by the aggressor over the victim:
  1. Penetration or infiltration: the deliberate infiltration of political and social groups within a victim state by the aggressor with the ultimate purpose of extending influence and control. The aggressor conceals its endgame, which goes beyond the normal influential nature of diplomacy and involves espionage.
  2. Forced disintegration or atomization: "is the breakdown of the political and social structure of the victim until the fabric of national morale disintegrates and the state is unable to resist further intervention". The aggressor may exploit the inevitable internal tensions between political, class, ethnic, religious, racial, and other groups. This concept is a similar strategy to 'divide and conquer'.
  3. Subversion and defection: Subversion is the "undermining or detachment of the loyalties of significant political and social groups within the victimized state, and their transference to the political or ideological causes of the aggressor". In lieu of total and direct transference, the aggressor may accept intermediate states that still meets its objectives, such as the favor of politically significant individuals. Furthermore, the formation of a counter-elite, made up of influential individuals and key leaders, within the victim state establishes the legitimacy and permanency of a new regime. Defection is the transference of allegiance of key individuals and leaders to the aggressor's camp. The individual could relocate or stay-in-place in the victim country, continually influencing local issues and events in the aggressor's favor. Defectors also provide insider information to the aggressor.
  • Coup d'état is the overthrowing of a government through the infiltration of the political, military, and social groups by a small segment of the state apparatus. The small segment exists within the state and targets the critical political levers of power within a government to neutralize opposition to the coup and post-coup governing force. Several pre-existing factors are necessary for a coup: political participation being limited to a small portion of the population, independence from foreign power influence and control, and power and decision-making authority concentrated within a political center and not diffused between regional authorities, businesses, or other groups.

A coup utilizes political resources to gain support within the existing state and neutralize or immobilize those who are capable of rallying against the coup. A successful coup occurs rapidly and after taking over the government, stabilizes the situation by controlling communications and mobility. Furthermore, a new government must gain acceptance from the public and military and administrative structures, by reducing the sense of insecurity. Ultimately, the new government will seek legitimacy in the eyes of its own people as well as seek foreign recognition. The coup d'état can be led by national forces or involve foreign influence, similar to foreign liberation or infiltration.

  • Paramilitary Operations: transitional political warfare ranging from small-scale use of violence with primitive organizational structure (e.g. sabotage) to full-scale conventional war. The transition and escalation includes a series of stages and depends on tactical and strategic objectives. Paramilitary activities include infiltration and subversion as well as small group operations, insurrection, and civil war.
  • Insurgency: an organized, protracted political warfare tool designed to weaken the control and eliminate the legitimacy of an established government, occupying power, or other political authority. An insurgency is an internal conflict, and the primary struggle is to mobilize local populations for political control and gain popular support towards the insurgents' cause. Insurgencies include political and military objectives, with the end goal of establishing a legitimate, rival state structure. Insurgencies are unconventional military conflicts which incorporate a variety of methods, ranging from coercive tools like intimidation and assassination, to political tools like propaganda and social services. An insurgency's approaches and objectives could involve perpetual disorder and violence demonstrating the government's inability to provide security for the populace, weakening the government and killing or intimidating any effective opposition against the government, intimidating the population and discouraging its participation in – or support for – political or legal processes, controlling or intimidating police and military forces (which limits their ability to respond to insurgent attacks) or by creating government repression by provoking over-reactions by security or military forces.


In antiquity

A coin of Constantine (c.337) showing a depiction of his labarum spearing a serpent.
 
The Chi-Rho symbol

The history of political warfare can be traced to antiquity. The Chinese general and strategist Sun Tzu captures its essence in the ancient Chinese military strategy book, The Art of War: "So to win a hundred victories in a hundred battles is not the highest excellence; the highest excellence is to subdue the enemy's army without fighting at all...The expert in using the military subdues the enemy's forces without going to battle, takes the enemy's walled cities without launching an attack, and crushes the enemy's state without protracted war."

There are abundant examples of political warfare in antiquity. In ancient Greece, a famous example is that of the Trojan Horse, which used deception for tactical military objectives. Propaganda was commonly utilized, including Greek rhetoric and theatre which used words and images to influence populations throughout the Hellenic world. This practice has left a lasting legacy of speech as a mechanism of political power, greater than force in solving disputes and inducing submission. During this same period, Alexander the Great used coinage imprinted with his own image, indirectly forcing conquered nations to accept his legitimacy as national ruler and to unite disparate nations together under his dominion.

Ancient Rome utilized similar political warfare as the Greeks including rhetoric, as displayed by Cicero; and art, as seen in coinage, statues, architecture, engineering, and mosaics. All of these elements were intended to portray Rome's imperial dominance over its subject nations and the superior nature of Roman society. Following a religious vision, the emperor Constantine I in AD 330 bound the Roman state to the universal Christian Church. In doing so, he linked "religious commitment with imperial ambition" that proved to be quite successful and powerful. One long-lasting symbol of this is the Chi Rho, which forms the first two letters of the Greeks' name for Christ. This symbol was used for over one thousand years by Constantine's successors as a symbol of "imperial majesty and divine authority" and still is a powerful symbol within Christianity.

By country

China

China's political leaders during this century have had to first create a nation before they could proceed to contend with other national actors in the international arena. Consequently, insofar as both the Chinese Communist Party and the Kuomintang subscribed to a political warfare concept during their formative years of struggle, the concept was as much concerned with creating national identity and defeating domestic adversaries as it was with China's ability to compete in the world. Since the founding of the PRC in 1949 they have centered much of their political warfare efforts within the United Front Work Department. The Chinese conception of political warfare includes the "Three Warfares" of public opinion warfare, psychological warfare, and legal warfare, among others.

Taiwan remains a major target of PRC political warfare efforts. China's political warfare campaign aims to isolate Taiwan from the international community and interfere in Taiwan's democratic system and institutions.

Soviet Union and Russia

Throughout the Cold War, the Soviet Union was committed to political warfare on classic totalitarian lines and continued to utilize propaganda towards internal and external audiences. "Active measures" (Russian: Активные мероприятия) was a Russian term to describe its political warfare activities both at home and abroad in support of Soviet domestic and foreign policy. Soviet efforts took many forms, ranging from propaganda, forgeries, and general disinformation to assassinations. The measures aimed to damage the enemy's image, create confusion, mould public opinion, and to exploit existing strains in international relations. The Soviet Union dedicated vast resources and attention to these active measures, believing that "mass production of active measures would have a significant cumulative effect over a period of several decades". Soviet active measures were notorious for targeting intended audience's public attitudes, to include prejudices, beliefs, and suspicions deeply rooted in the local history. Soviet campaigns fed disinformation that was psychologically consistent with the audience. Examples of Soviet active measures include:

  • Operation Trust: was a counterintelligence operation conducted by Soviet intelligence against domestic and foreign adversaries. The operation, which ran from 1921 to 1929, set up a fake anti-Bolshevik underground organization, "Monarchist Union of Central Russia", MUCR (Монархическое объединение Центральной России, МОЦР), which claimed to plan a conspiracy to overthrow the Soviet government. The Trust aimed to create the view that communism was over in Russia and the Soviet Union would abandon its revolutionary ways. Western intelligence services supported the fake anti-Bolshevik dissidents who provided false intelligence reports. The operation's purpose was to identify real dissidents and anti-Bolsheviks, internally and abroad. The operation resulted in the arrests and executions of Russian exile leaders and the general demoralization of anti-Soviet efforts.
  • The "Rumor" Campaign: In October 1985, a Soviet weekly Literaturnaya Gazeta drew attention to a story in an obscure Indian paper, The Patriot, which alleged that the U.S government engineered the AIDS virus during biological warfare research in the U.S., and that it was being spread throughout the world by U.S. servicemen who had been used as guinea pigs for the experiment. The story was broadcast by Moscow's Radio Peace and Progress in English and Turkish broadcasts to Asian countries, some of which had important U.S. military bases. The "Rumor" campaign was highly effective in the 1980s and continues to resurface today throughout the world.

Communist strategy and tactics continually focused on revolutionary objectives, "for them the real war is the political warfare waged daily under the guise of peace". the purpose of which is to "disorient and disarm the opposition...to induce the desire to surrender in opposing peoples...to corrode the entire moral, political, and economic infrastructure of a nation". Lenin's mastery of "politics and struggle", remained objectives for the Soviet Union and other global communist regimes, such as the People's Republic of China.

Soviet political warfare in Afghanistan

The Soviet Union remains a comprehensive example of an aggressive nation which expanded its empire through covert infiltration and direct military involvement. Following World War II, the Soviet Union believed European economies would disintegrate, leaving social and economic chaos and allowing for Soviet expansion into new territories. The Soviets quickly deployed organizational weapons such as non-political front groups, sponsored 'spontaneous' mass appeals, and puppet politicians. While many of these countries' political and social structures were in post-war disarray, the Soviet Union's proxy communist parties were well-organized and able to take control of these weak, newly formed Eastern European governments. Moreover, the clandestine operations of the Soviet intelligence services and the occupying forces of the Soviet military further infiltrated the political and social spheres of the new satellites. Conversely, in 1979, the Soviet Union was unable to successfully penetrate the Afghan society after supporting a coup which brought a new Marxist government to power. While Soviet units were already in Kabul, Afghanistan at the time of the coup, additional Soviet troops arrived to reinforce the units and seize important provincial cities, bringing the total of Soviet troops inside Afghanistan to 125,000–140,000. The Soviets were unprepared for the Afghan resistance which included classic guerrilla tactics with foreign support. In 1989, Soviet forces withdrew from Afghanistan, having been unable to infiltrate the Afghan society or immobilize the resistance.

Taiwan

Logo of political warfare in Taiwan

The Republic of China Government in Taiwan recognized that its Communist adversary astutely employed political warfare to capitalize upon Kuomintang weaknesses over the years since Sun Yat-sen first mounted his revolution in the 1920s, and Chiang Kai-shek's regime had come to embrace a political warfare philosophy as both a defensive necessity and as the best foundation for consolidating its power in hope of their optimistic goal of "retaking the mainland". Both the Nationalist and Communist Chinese political warfare doctrines stem from the same historical antecedents at the Whampoa Military Academy in 1924 under Soviet tutelage.

The Nationalist Chinese experience with political warfare can be treated in a much more tangible way than merely tracing doctrinal development. In the Taiwan of the 1970s, the concept was virtually synonymous with the General Political Warfare Department of the Ministry of National Defense, which authored political doctrine and was the culmination of a series of organizational manifestations of its application.

In the 21st century political warfare is primarily the responsibility of the Political Warfare Bureau.

United States

Creation of political warfare capacity

Logo used on aid delivered to European countries during the Marshall Plan.

American foreign policy demonstrates a tendency to move towards political warfare in times of tension and perceived threat, and toward public diplomacy in times of improved relations and peace. American use of political warfare depends on its central political vision of the world and its subsequent foreign policy objectives. After World War II, the threat of Soviet expansion brought two new aims for American political warfare:

  1. To restore Western Europe through military, economic, and political support
  2. To weaken the Soviet hold on Eastern Europe through propaganda

President Harry S. Truman established a government political warfare capability in the National Security Act of 1947. The act created the U.S. National Security Council, which became the infrastructure necessary to apply military power to political purposes. Additionally, the United States crafted the Marshall Plan, which provided funding to rebuild, from 1947 to 1951, the European countries devastated by war. President Truman voiced the United States' national, universalist vision for political warfare against the Soviet Union in an address before Congress on March 12, 1947, thereby establishing the Truman Doctrine:

The peoples of a number of countries of the world have recently had totalitarian regimes forced upon them against their will. The Government of the United States has made frequent protests against coercion and intimidation, in violation of the Yalta agreement, in Poland, Rumania, and Bulgaria. I must also state that in a number of other countries there have been similar developments.

One way of life is based upon the will of the majority, and is distinguished by free institutions, representative government, free elections, guarantees of individual liberty, freedom of speech and religion, and freedom from political oppression.

The second way of life is based upon the will of a minority forcibly imposed upon the majority. It relies upon terror and oppression, a controlled press and radio; fixed elections, and the suppression of personal freedoms.

I believe that it must be the policy of the United States to support free peoples who are resisting attempted subjugation by armed minorities or by outside pressures.

I believe that we must assist free peoples to work out their own destinies in their own way.

I believe that our help should be primarily through economic and financial aid which is essential to economic stability and orderly political processes.

The seeds of totalitarian regimes are nurtured by misery and want. They spread and grow in the evil soil of poverty and strife. They reach their full growth when the hope of a people for a better life has died. We must keep that hope alive.

The free peoples of the world look to us for support in maintaining their freedoms.

If we falter in our leadership, we may endanger the peace of the world – and we shall surely endanger the welfare of our own nation.

Containment policy

The Truman Doctrine was the post-WWII basis for American political warfare operations on which the United States government went further to formulate an active, defensive strategy to contain the Soviet threat. On 4 May 1948, George F. Kennan, the father of the containment policy, wrote the Policy Planning Staff Memorandum titled "The Inauguration of Organized Political Warfare". This National Security Council (NSC) memo established a directorate of political warfare operations, under the control of the NSC, known as the Consultative (or Evaluation) Board of the National Security Council. This directorate fell under the authority of the Secretary of State, while the Board had complete authority over covert political operations. It recognized political warfare as one instrument in the United States' grand strategy. Kennan defined 'political warfare' as "the employment of all means at a nation's command, short of war, to achieve its national objectives. Such actions are both overt and covert. They range from such overt actions as political alliances, economic measures (such as ERP – the Marshall Plan), and 'white' propaganda to such covert operations as clandestine support of 'friendly' foreign elements, 'black' psychological warfare and even encouragement of underground resistance in hostile states."

The memo further defined four projects that were activated by the Board to combat growing Communist influence abroad, including:

  • Liberation Committees: to encourage the formation of a public American organization which will sponsor selected political refugee committees to give support and guidance to national movements gestating in the Soviet World;
  • Support of indigenous anti-communist elements: within threatened countries of the free world, to include covertly using private intermediaries;
  • Underground activities behind the Iron Curtain
  • Preventive direct action in free countries: only in cases of dire necessity. This covert operation involved: control over anti-sabotage activities in the Venezuelan oil fields, American sabotage of Near Eastern oil installations on the verge of Soviet capture, and designation of key individuals threatened by the Kremlin who should be protected or removed elsewhere.

Cold War era

RFE/RL logo

The United States used gray and black propaganda research, broadcasting, and print media operations during the Cold War to achieve its political warfare goals. These operations were conducted against Eastern European targets from Western Europe by two public-private organizations supported partly by the Central Intelligence Agency and the NSC, and partly by private corporations. These organizations were Free Europe, which was launched in 1941 and targeted Eastern Europe, and the American Committee for Liberation (AmComLib) created in 1951 to broadcast information into Soviet Russia. Both were renamed shortly thereafter and combined as Radio Free Europe/Radio Liberty (RFE/RL). Many RFE/RL recruits came either from European emigrants families who were strongly anti-Communist or from US government agencies, most notably from CIA. Officially, "the US government denied any responsibility for the radios and took care to conceal the channels of funding, personnel recruitment, and policy influence. Obviously, the major support was American, but it was plausibly not official American and it could be excluded from diplomatic intercourse and international legal complication." RFE/RL was considered to be a gray operation until its existence was publicly acknowledged by "activists" in the United States during the late 1960s. The goal of the radios was to present the truth to suppressed peoples behind the Iron Curtain "to aid in rebuilding a lively and diversified intellectual life in Europe which could ... defeat Soviet ... incursions on their freedom".

In addition, Voice of America (VOA) started broadcasting to the Soviet citizens in 1947 under the pretext of countering "more harmful instances of Soviet propaganda directed against American leaders and policies" on the part of the internal Soviet Russian-language media. The Soviet Union responded by initiating electronic jamming of VOA broadcasts on April 24, 1949.

In the fall of 1950 a group of scholars including physicists, historians and psychologists from Harvard University, the Massachusetts Institute of Technology and RAND Corporation undertook a research study of psychological warfare for the Department of State. The Project Troy Report to the Secretary of State, presented to Secretary of State on 1 February 1951, made various proposals for political warfare, including possible methods of minimizing the effects of Soviet jamming on the Voice of America broadcasts. It can be assumed that the Truman administration tried to implement plans established by the Project Troy in the project Overload and Delay. The purpose of the latter was to break the Stalinist system by increasing the number of input points in the system and by creating complex and unpredictable situations requiring action.

An overt, non-governmental form of political warfare during the Cold War emerged after President Ronald Reagan's 8 June 1982 speech to the British Parliament. In his speech, Reagan appealed for a "global crusade for democracy" and as a result, the National Endowment for Democracy (NED) was created in December 1983. The NED was a non-governmental organization (NGO) based on four fundamental foundations:

  • The National Democratic Institute
  • The National Republican Institute to dispense funds and training to politicians and political parties;
  • The Center for International Private Enterprise to provide training, funding and networking opportunities for business associations;
  • AFL–CIO to assist foreign trade unions.

The NED "funded programs in support of candidates acceptable to the US in elections in Grenada, Panama, El Salvador, and Guatemala throughout 1984 and 1985 in order to prevent communist victories, and create stable pro-US governments". It was also active in Europe, funding groups to carry promote pro-North Atlantic Treaty Organization (NATO) propaganda in Britain, as well as a "right wing French student organisation ... linked to fascist paramilitaries". Other notable efforts included anti-Sandinista propaganda and opposition efforts in Nicaragua as well as anti-Communist propaganda and opposition efforts in support of the Solidarity movement in Poland between 1984 and 1990. According to a 1991 interview in The Washington Post with one of the creators of the NED, Allen Weinstein, "a lot of what we (NED) do today was done covertly 25 years ago by the CIA".

Spanish Golden Age

From Wikipedia, the free encyclopedia
 
In ictu oculi ("In the blink of an eye"), a vanitas by Juan de Valdés Leal
 
Façade of the Monastery of El Escorial

The Spanish Golden Age (Spanish: Siglo de Oro [ˈsiɣlo ðe ˈoɾo], "Golden Century") is a period of flourishing in arts and literature in Spain, coinciding with the political rise of the Spanish Empire under the Catholic Monarchs of Spain and the Spanish Habsburgs. The greatest patron of Spanish art and culture during this period was King Philip II (1556–1598), whose royal palace, El Escorial, invited the attention of some of Europe's greatest architects and painters such as El Greco, who infused Spanish art with foreign styles and helped create a uniquely Spanish style of painting. It is associated with the reigns of Isabella I, Ferdinand II, Charles V, Philip II, Philip III, and Philip IV, when Spain was one of the most powerful countries in the world.

The start of the Golden Age can be placed in 1492, with the end of the Reconquista, the voyages of Christopher Columbus to the New World, and the publication of Antonio de Nebrija's Grammar of the Castilian Language. It roughly ended with the Treaty of the Pyrenees in 1659 that ended the Franco-Spanish War of 1635 to 1659. Some extend the Golden Age up to 1681 with the death of the Pedro Calderón de la Barca, the last great writer of the age. It can be divided into a Plateresque/Renaissance period and the early part of the Spanish Baroque period.

Spanish literature blossomed as well, most famously demonstrated in the work of Miguel de Cervantes, the author of Don Quixote de la Mancha. Spain's most prolific playwright, Lope de Vega, wrote possibly one thousand plays during his lifetime, of which over four hundred survive to the present day. Diego Velázquez, regarded as one of the most influential painters of European history and a greatly respected artist in his own time, was patronized by King Philip IV and his chief minister, the Count-Duke of Olivares. The legacy of Diego Velázquez includes several portraits that demonstrate his style and skill.

Some of Spain's greatest music is regarded as having been written in the period. Such composers as Tomás Luis de Victoria, Cristóbal de Morales, Francisco Guerrero, Luis de Milán and Alonso Lobo helped to shape Renaissance music and the styles of counterpoint and polychoral music, and their influence lasted far into the Baroque period which resulted in a revolution of music.

The realms of Philip II of Spain
 
  Territories administered by the Council of Castile
  Territories administered by the Council of Aragon
  Territories administered by the Council of Portugal
  Territories administered by the Council of Italy
  Territories administered by the Council of the Indies
  Territories appointed to the Council of Flanders

Painting

Spain, in the time of the Italian Renaissance, had seen few great artists come to its shores. The Italian holdings and relationships made by Queen Isabella's husband and later Spain's sole monarch, Ferdinand of Aragon, launched a steady traffic of intellectuals across the Mediterranean between Valencia, Seville, and Florence. Luis de Morales, one of the leading exponents of Spanish Mannerist painting, retained a distinctly Spanish style in his work, reminiscent of medieval art. Spanish art, particularly that of Morales, contained a strong mark of mysticism and religion that was encouraged by the counter-reformation and the patronage of Spain's strongly Catholic monarchs and aristocracy. Spanish rule of Naples was important for making connections between Italian and Spanish art, with many Spanish administrators bringing Italian works back to Spain.

El Greco

Known for his unique expressionistic style that met with both puzzlement and admiration, El Greco (which means "The Greek") was not Spanish, having been born Domenikos Theotokopoulos in Crete. He studied the great Italian masters of his time—Titian, Tintoretto, and Michelangelo—when he lived in Italy from 1568 to 1577. According to legend, he asserted that he would paint a mural that would be as good as one of Michelangelo's, if one of the Italian artist's murals was demolished first. El Greco quickly fell out of favor in Italy, but soon found a new home in the city of Toledo, in central Spain. He was influential in creating a style based on impressions and emotion, featuring elongated fingers and vibrant color and brushwork. Uniquely, his works featured faces that captured expressions of sombre attitudes and withdrawal while still having his subjects bear witness to the terrestrial world. His paintings of the city of Toledo became models for a new European tradition in landscapes, and influenced the work of later Dutch masters. Spain at this time was an ideal environment for the Venetian-trained painter. Art was flourishing in the empire and Toledo was a great place to get commissions.

Las Meninas (1656, English: The Maids of Honour) by Diego Velázquez

Diego Velázquez

Diego Velázquez was born on June 6, 1599, in Seville. Both parents were from minor nobility. He was the oldest of six children. Velázquez is widely regarded as one of Spain's most important and influential artists. He was a court painter for King Philip IV and found an increasingly high demand for his portraits from statesmen, aristocrats, and clergymen across Europe. His portraits of the King, his chief minister, the Count-duke of Olivares, and the Pope himself demonstrated a belief in artistic realism and a style comparable to many of the Dutch masters. In the wake of the Thirty Years' War, Velázquez met the Marqués de Spinola and painted his famous Surrender of Breda celebrating Spinola's earlier victory. Spinola was struck by his ability to express emotion through realism in both his portraits and landscapes; his work in the latter, in which he launched one of European art's first experiments in outdoor lighting, became another lasting influence on Western painting. Velázquez's friendship with Bartolomé Esteban Murillo, a leading Spanish painter of the next generation, ensured the enduring influence of his artistic approach.

Velázquez's most famous painting is the celebrated Las Meninas, in which the artist includes himself as one of the subjects.

The Birth of the Virgin by Francisco de Zurbarán

Francisco de Zurbarán

The religious element in Spanish art, in many circles, grew in importance with the counter-reformation. The austere, ascetic, and severe work of Francisco de Zurbarán exemplified this thread in Spanish art, along with the work of composer Tomás Luis de Victoria. Philip IV actively patronized artists who agreed with his views on the counter-reformation and religion. The mysticism of Zurbarán's work—influenced by Saint Theresa of Avila—became a hallmark of Spanish art in later generations. Influenced by Michelangelo da Caravaggio and the Italian masters, Zurbarán devoted himself to an artistic expression of religion and faith. His paintings of St. Francis of Assisi, the immaculate conception, and the crucifixion of Christ reflected a third facet of Spanish culture in the seventeenth century, against the backdrop of religious war across Europe. Zurbarán broke from Velázquez's sharp realist interpretation of art and looked, to some extent, to the emotive content of El Greco and the earlier mannerist painters for inspiration and technique, though Zurbarán respected and maintained the lighting and physical nuance of Velázquez.

It is unknown whether Zurbarán had the opportunity to copy the paintings of Caravaggio; at any rate, he adopted Caravaggio's realistic use of chiaroscuro. The painter who may have had the greatest influence on his characteristically severe compositions was Juan Sánchez Cotán. Polychrome sculpture—which by the time of Zurbarán's apprenticeship had reached a level of sophistication in Seville that surpassed that of the local painters—provided another important stylistic model for the young artist; the work of Juan Martínez Montañés is especially close to Zurbarán's in spirit.

He painted directly from nature, and he made great use of the lay-figure in the study of draperies, in which he was particularly proficient. He had a special gift for white draperies; as a consequence, the houses of the white-robed Carthusians are abundant in his paintings. To these rigid methods, Zurbarán is said to have adhered throughout his career, which was prosperous, wholly confined to Spain, and varied by few incidents beyond those of his daily labour. His subjects were mostly severe and ascetic religious vigils, the spirit chastising the flesh into subjection, the compositions often reduced to a single figure. The style is more reserved and chastened than Caravaggio's, the tone of color often quite bluish. Exceptional effects are attained by the precisely finished foregrounds, massed out largely in light and shade.

Bartolomé Esteban Murillo

The Virgin of the Rosary (1675–80) by Bartolomé Esteban Murillo

Bartolomé Esteban Murillo began his art studies under Juan del Castillo in Seville. Murillo became familiar with Flemish painting; the great commercial importance of Seville at the time ensured that he was also subject to influences from other regions. His first works were influenced by Zurbarán, Jusepe de Ribera and Alonso Cano, and he shared their strongly realist approach. As his painting developed, his more important works evolved towards the polished style that suited the bourgeois and aristocratic tastes of the time, demonstrated especially in his Roman Catholic religious works.

In 1642, at the age of 26 he moved to Madrid, where he most likely became familiar with the work of Velázquez, and would have seen the work of Venetian and Flemish masters in the royal collections; the rich colors and softly modeled forms of his subsequent work suggest these influences. He returned to Seville in 1645. In that year, he painted thirteen canvases for the monastery of St. Francisco el Grande in Seville which gave his reputation a well-deserved boost. Following the completion of a pair of pictures for the Seville Cathedral, he began to specialise in the themes that brought him his greatest successes, Mary and child Jesus, and the Immaculate Conception.

After another period in Madrid, from 1658 to 1660, he returned to Seville, where he died. Here he was one of the founders of the Academia de Bellas Artes (Academy of Fine Arts), sharing its direction, in 1660, with the architect, Francisco Herrera the Younger. This was his period of greatest activity, and he received numerous important commissions, among them the altarpieces for the Augustinian monastery, the paintings for Santa María la Blanca (completed in 1665), and others.

Other significant painters

Sculpture

Entombment by Juan de Juni

Sculptors of the Renaissance

Sculptors of the Early Baroque period

Architecture

Palace of Charles V

Panoramic view of the lower level patio of the Palace

The Palace of Charles V is a Renacentist construction, located on the top of the hill of the Assabica, inside the Nasrid fortification of the Alhambra. It was commanded by Charles V, Holy Roman Emperor, who wished to establish his residence close to the Alhambra palaces. Although the Catholic Monarchs had already altered some rooms of the Alhambra after the conquest of the city in 1492, Charles V intended to construct a permanent residence befitting an emperor. The project was given to Pedro Machuca, an architect whose biography and influences are poorly understood. Even if accounts that place Machuca in the atelier of Michelangelo are accepted, at the time of the construction of the palace in 1527 the latter had yet to design the majority of his architectural works. At the time, Spanish architecture was immersed in the Plateresque style, still with traces of Gothic origin. Machuca built a palace corresponding stylistically to Mannerism, a mode still in its infancy in Italy.

El Escorial

The library of El Escorial

El Escorial is a historical residence of the king of Spain. It is one of the Spanish royal sites and functions as a monastery, royal palace, museum, and school. It is located about 45 kilometres (28 mi) northwest of the Spanish capital, Madrid, in the town of San Lorenzo de El Escorial. El Escorial comprises two architectural complexes of great historical and cultural significance: El Real Monasterio de El Escorial itself and La Granjilla de La Fresneda, a royal hunting lodge and monastic retreat about five kilometres away. These sites have a dual nature; that is to say, during the sixteenth and seventeenth centuries, they were places in which the temporal power of the Spanish monarchy and the ecclesiastical predominance of the Roman Catholic religion in Spain found a common architectural manifestation. El Escorial was, at once, a monastery and a Spanish royal palace. Originally a property of the Hieronymite monks, it is now a monastery of the Order of Saint Augustine.

Philip II of Spain, reacting to the Protestant Reformation sweeping through Europe during the sixteenth century, devoted much of his lengthy reign (1556–1598) and much of his seemingly inexhaustible supply of New World silver to stemming the Protestant tide sweeping through Europe, while simultaneously fighting the Islamic Ottoman Empire. His protracted efforts were, in the long run, partly successful. However, the same counter-reformational impulse had a much more benign expression, thirty years earlier, in Philip's decision to build the complex at El Escorial.

Philip engaged the Spanish architect, Juan Bautista de Toledo, to be his collaborator in the design of El Escorial. Juan Bautista had spent the greater part of his career in Rome, where he had worked on the basilica of St. Peter's, and in Naples, where he had served the king's viceroy, whose recommendation brought him to the king's attention. Philip appointed him architect-royal in 1559, and together they designed El Escorial as a monument to Spain's role as a center of the Christian world.

Plaza Mayor in Madrid

Plaza Mayor with the Casa de la Panadería to the left

The Plaza Mayor in Madrid was built during the Habsburg period is a central plaza in the city of Madrid, Spain. It is located only a few blocks away from another famous plaza, the Puerta del Sol. The Plaza Mayor is rectangular in shape, measuring 129 by 94 meters, and is surrounded by three-story residential buildings having 237 balconies facing the Plaza. It has a total of nine entranceways. The Casa de la Panadería, serving municipal and cultural functions, dominates the Plaza Mayor.

The origins of the Plaza go back to 1589 when Philip II of Spain asked Juan de Herrera, a renowned Renaissance architect, to discuss a plan to remodel the busy and chaotic area of the old Plaza del Arrabal. Juan de Herrera was the architect who designed the first project in 1581 to remodel the old Plaza del Arrabal but construction didn't start until 1617, during Philip III's reign. The king asked Juan Gómez de Mora to continue with the project, and he finished the porticoes in 1619. Nevertheless, the Plaza Mayor as we know it today is the work of the architect Juan de Villanueva who was entrusted with its reconstruction in 1790 after a spate of big fires. Giambologna's equestrian statue of Philip III dates to 1616, but it was not placed in the center of the square until 1848.

Granada Cathedral

Inner view of the cathedral

Unlike most cathedrals in Spain, construction of this cathedral had to await the acquisition of the Nasrid kingdom of Granada from its Muslim rulers in 1492; while its very early plans had Gothic designs, such as are evident in the Royal Chapel of Granada by Enrique Egas, the construction of the church in the main occurred at a time when Renaissance designs were supplanting the Gothic regnant in Spanish architecture of prior centuries. Foundations for the church were laid by the architect Egas starting from 1518 to 1523 atop the site of the city's main mosque; by 1529, Egas was replaced by Diego de Siloé who labored for nearly four decades on the structure from ground to cornice, planning the triforium and five naves instead of the usual three. Most unusually, he created a circular capilla mayor rather than a semicircular apse, perhaps inspired by Italian ideas for circular 'perfect buildings' (e.g. in Alberti's works). Within its structure the cathedral combines other orders of architecture. It took 181 years for the cathedral to be built.

Subsequent architects included Juan de Maena (1563–1571), followed by Juan de Orea (1571–1590), and Ambrosio de Vico (1590-?). In 1667 Alonso Cano, working with Gaspar de la Peña, altered the initial plan for the main façade, introducing Baroque elements. The magnificence of the building would be even greater, if the two large 81 meter towers foreseen in the plans had been built; however the project remained incomplete for various reasons, among them, financial.

The Granada Cathedral had been intended to become the royal mausoleum for Charles I of Spain, but Philip II of Spain moved the site for his father and subsequent kings to El Escorial outside of Madrid.

The main chapel contains two kneeling effigies of the Catholic King and Queen, Ferdinand and Isabel, by Pedro de Mena y Medrano. The busts of Adam and Eve were made by Alonso Cano. The Chapel of the Trinity has a marvelous retablo with paintings by El Greco, Alonso Cano, and José de Ribera (The Spagnoletto).

Cathedral of Valladolid

Cathedral of Valladolid's façade

The Cathedral of Valladolid, like all the buildings of the late Spanish Renaissance built by Herrera and his followers, is known for its purist and sober decoration, its style being the typical Spanish clasicismo, also called "Herrerian". Using classical and renaissance decorative motifs, Herrerian buildings are characterized by their extremely sober decorations, its formal austerity, and its like for monumentality.

The cathedral has its origins in a late gothic Collegiate which was started during the late 15th century, for before becoming capital of Spain Valladolid was not a bishopry see, and thus it lacked the right of building a cathedral. However, soon enough the Collegiate became obsolete due to the changes of taste of the day, and thanks to the newly established episcopal see in the city, the Town Council decided to build a cathedral that would shade similar constructions in neighbouring capitals.

Had the building been finished, it would have been one of the biggest cathedrals in Spain. When the building was started, Valladolid was the de facto capital of Spain, housing king Philip II and his court. However, due to strategical and geopolitical reasons, by the 1560s the capital was moved to Madrid, thus Valladolid losing its political and economical relevance. By the late sixteenth century, Valladolid's importance had been severely resented, and many of the monumental projects such as the cathedral, started during its former and glorious days, had to be modified due to the lack of proper finance. Thus, the building that nowadays stands could not be finished in all its splendour, and because of several additions built during the 17th and 18th centuries, it lacks the purported stylistical uniformity sought by Herrera. Indeed, although mainly faithful to the project of Juan de Herrera, the building would undergo many modifications, such as the addition to the top of the main façade, a work by Churriguera.

Significant architects

Renaissance and Plateresque period

Early Baroque period

Music

Tomás Luis de Victoria

Contemporary printing of the sheet music for Tomás Luis de Victoria's Officium Defunctorum.

Tomás Luis de Victoria, a Spanish composer of the sixteenth century, mainly of choral music, is widely regarded as one of the greatest Spanish classical composers. He joined the cause of Ignatius of Loyola in the fight against the Reformation and in 1575 became a priest. He lived for a short time in Italy, where he became acquainted with the polyphonic work of Giovanni Pierluigi da Palestrina. Like Zurbarán, Victoria mixed the technical qualities of Italian art with the religion and culture of his native Spain. He invigorated his work with emotional appeal and experimental, mystical rhythm and choruses. He broke from the dominant tendency among his contemporaries by avoiding complex counterpoint, preferring longer, simpler, less technical and more mysterious melodies, employing dissonance in ways that the Italian members of the Roman School shunned. He demonstrated considerable invention in musical thought by connecting the tone and emotion of his music to those of his lyrics, particularly in his motets. Like Velázquez, Victoria was employed by the monarch – in Victoria's case, in the service of the queen. The Requiem he wrote upon her death in 1603 is regarded as one of his most enduring and complex works.

Francisco Guerrero

Francisco Guerrero, a Spanish composer of the 16th century. He was second only to Victoria as a major Spanish composer of church music in the second half of the 16th century. Of all the Spanish Renaissance composers, he was the one who lived and worked the most in Spain. Others, e.g. Morales and Victoria, spent large portions of their careers in Italy. Guerrero's music was both religious and secular, unlike that of Victoria and Morales, the two other Spanish 16th-century composers of the first rank. He wrote numerous secular songs and instrumental pieces, in addition to masses, motets, and Passions. He was able to capture an astonishing variety of moods in his music, from elation to despair, longing, depression, and devotion; his music remained popular for hundreds of years, especially in cathedrals in Latin America. Stylistically he preferred homophonic textures, rather like his Spanish contemporaries, and he wrote memorable, singable lines. One interesting feature of his style is how he anticipated functional harmonic usage: there is a case of a Magnificat discovered in Lima, Peru, once thought to be an anonymous 18th century work, which turned out to be a work of his.

Alonso Lobo

Victoria's work was complemented by Alonso Lobo – a man Victoria respected as his equal. Lobo's work – also choral and religious in its content – stressed the austere, minimalist nature of religious music. Lobo sought out a medium between the emotional intensity of Victoria and the technical ability of Palestrina; the solution he found became the foundation of the Baroque musical style in Spain.

Cristóbal de Morales

Regarded as one of the finest composers in Europe around the middle of the 16th century, Cristóbal de Morales was born in Seville in 1500 and employed in Rome from 1535 until 1545 by the Vatican. Almost all of his music is religious, and all of it is vocal, though instruments may have been used in an accompanying role in performance. Morales also wrote two masses on the famous L'homme armé tune, which was often set by composers in the late 15th and 16th centuries. One of these masses is for four voices, and the other for five. The four voice mass uses the tune as a strict cantus firmus, and the setting for five voices treats it more freely, migrating it from one voice to another.

Other significant musicians

Literature

Cervantes' Don Quixote (1605), original title page

The Spanish Golden Age was a time of great flourishing in poetry, prose and drama.

Cervantes and Don Quixote

Regarded by many as one of the finest works in any language, El ingenioso hidalgo Don Quixote de la Mancha by Miguel de Cervantes was the first novel published in Europe; it gave Cervantes a stature in the Spanish-speaking world comparable to his contemporary William Shakespeare in English. The novel, like Spain itself, was caught between the Middle Ages and the modern world. A veteran of the Battle of Lepanto (1571), Cervantes had fallen on hard times in the late 1590s and was imprisoned for debt in 1597, and some believe that during these years he began work on his best-remembered novel. The first part of the novel was published in 1605; the second in 1615, a year before the author's death. Don Quixote resembled both the medieval, chivalric romances of an earlier time and the novels of the early modern world. It parodied classical morality and chivalry, found comedy in knighthood, and criticized social structures and the perceived madness of Spain's rigid society. The work has endured to the present day as a landmark in world literary history, and it was an immediate international hit in its own time, interpreted variously as a satirical comedy, social commentary and forbearer of self-referential literature.

Lope de Vega and Spanish drama

Title page of a comedy by Spanish playwright Lope de Vega

A contemporary of Cervantes, Lope de Vega consolidated the essential genres and structures which would characterize the Spanish commercial drama, also known as the "Comedia", throughout the 17th century. While Lope de Vega wrote prose and poetry as well, he is best remembered for his plays, particularly those grounded in Spanish history. Like Cervantes, Lope de Vega served with the Spanish army and was fascinated with the Spanish nobility. In the hundreds of plays he wrote, with settings ranging from the Biblical times to legendary Spanish history to classical mythology to his own time, Lope de Vega frequently took a comical approach just as Cervantes did, taking a conventional moral play and dressing it up in good humor and cynicism. His stated goal was to entertain the public, much as Cervantes's was. In bringing morality, comedy, drama, and popular wit together, Lope de Vega is often compared to his English contemporary Shakespeare. Some have argued that as a social critic, Lope de Vega attacked, like Cervantes, many of the ancient institutions of his country – aristocracy, chivalry, and rigid morality, among others. Lope de Vega and Cervantes represented an alternative artistic perspective to the religious asceticism of Francisco Zurbarán. Lope de Vega's "cloak-and-sword" plays, which mingled intrigue, romance, and comedy together were carried on by his literary successor, Pedro Calderón de la Barca, in the later seventeenth century.

Poetry

This period also produced some of the most important Spanish works of poetry. The introduction and influence of Italian Renaissance verse is apparent perhaps most vividly in the works of Garcilaso de la Vega and illustrate a profound influence on later poets. Mystical literature in Spanish reached its summit with the works of San Juan de la Cruz and Teresa of Ávila. Baroque poetry was dominated by the contrasting styles of Francisco de Quevedo and Luis de Góngora; both had a lasting influence on subsequent writers, and even on the Spanish language itself. Lope de Vega was a gifted poet of his own, and there were a vast quantity of remarkable poets at that time, though less known: Francisco de Rioja, Bartolomé Leonardo de Argensola, Lupercio Leonardo de Argensola, Bernardino de Rebolledo, Rodrigo Caro, and Andrés Rey de Artieda. Another poet was Sor Juana Inés de la Cruz, from the Spanish colonies overseas, the New Spain ( modern day Mexico).

The picaresque genre flourished in this era, describing the life of pícaros, living by their wits in a decadent society. Distinguished examples are El buscón, by Francisco de Quevedo, Guzmán de Alfarache by Mateo Alemán, Estebanillo González and the anonymously published Lazarillo de Tormes (1554), which created the genre.

Other significant authors

Other well-known playwrights of the period include:

Rhetoric

As elsewhere in Europe, Spanish scholars participated in the humanist recovery and theorizing of Greek and Roman rhetorics. Early Spanish humanists include Antonio Nebrija and Juan Luis Vives. Spanish rhetoricians who discussed Ciceronianism include Juan Lorenzo Palmireno and Pedro Juan Núñez. Famous Spanish Ramists include Francisco Sánchez de Brozas, Pedro Juan Núñez, Fadrique Furió Ceriol, and Luis de Verga. Many other rhetoricians turned to Greek rhetorics from Hermogenes and Longinus which were preserved by Byzantine scholars, especially George of Trebizond. These Byzantine-inspired Spanish rhetoricians include Antonio Lull, Pedro Juan Núñez, and Luis de Granada. There were also many translators of progymnasmata, including Francisco de Vergara, Francisco Escobar, Juan de Mal Lara, Juan Pérez, Antionio Lull, Juan Lorenzo Palmireno, and Pedro Juan Núñez. Another important Spanish rhetorician is Cypriano Soarez, whose rhetorical handbook was a key textbook in the Jesuit Ratio studiorum which was used in Jesuit education throughout the Spanish empire. Diego de Válades´s Rhetorica christiana is the first Western rhetoric published by a native of México. Besides Soarez´s De arte rhetorica, the progymnasmata by Pedro Juan Núñez was also published in Mexico City. Examples of Nahua oratory (huehuetlatolli) were collected by Andrés de Olmos and Bernardino de Sahagún.

Triboluminescence

From Wikipedia, the free encyclopedia
 
Triboluminescence of nicotine L-salicylate

Triboluminescence is a phenomenon in which light is generated when a material is mechanically pulled apart, ripped, scratched, crushed, or rubbed (see tribology). The phenomenon is not fully understood, but appears to be caused by the separation and reunification of static electrical charges. The term comes from the Greek τρίβειν ("to rub"; see tribology) and the Latin lumen (light). Triboluminescence can be observed when breaking sugar crystals and peeling adhesive tapes.

Triboluminescence is often used as a synonym for fractoluminescence (a term sometimes used when referring only to light emitted from fractured crystals). Triboluminescence differs from piezoluminescence in that a piezoluminescent material emits light when it is deformed, as opposed to broken. These are examples of mechanoluminescence, which is luminescence resulting from any mechanical action on a solid.

History

An Uncompahgre Ute Buffalo rawhide ceremonial rattle filled with quartz crystals. Flashes of light are visible when the quartz crystals are subjected to mechanical stress in darkness.

Uncompahgre Ute indigenous people

The Uncompahgre Ute indigenous people from Central Colorado are one of the first documented groups of people in the world credited with the application of mechanoluminescence involving the use of quartz crystals to generate light. The Ute constructed special ceremonial rattles made from buffalo rawhide which they filled with clear quartz crystals collected from the mountains of Colorado and Utah. When the rattles were shaken at night during ceremonies, the friction and mechanical stress of the quartz crystals impacting together produced flashes of light visible through the translucent buffalo hide.

First scientific reports

The first recorded observation is attributed to English scholar Francis Bacon when he recorded in his 1620 Novum Organum that "It is well known that all sugar, whether candied or plain, if it be hard, will sparkle when broken or scraped in the dark." The scientist Robert Boyle also reported on some of his work on triboluminescence in 1663. In the late 1790s, sugar production began to produce more refined sugar crystals. These crystals were formed into a large solid cone for transport and sale. This solid cone of sugar had to be broken into usable chunks using a device known as sugar nips. People began to notice that as sugar was "nipped" in low light, tiny bursts of light were visible.

A historically important instance of triboluminescence occurred in Paris in 1675. Astronomer Jean-Felix Picard observed that his barometer was glowing in the dark as he carried it. His barometer consisted of a glass tube that was partially filled with mercury. Whenever the mercury slid down the glass tube, the empty space above the mercury would glow. While investigating this phenomenon, researchers discovered that static electricity could cause low-pressure air to glow. This discovery revealed the possibility of electric lighting.

Mechanism of action

Materials scientists have not yet arrived at a full understanding of the effect, but the current theory of triboluminescence — based upon crystallographic, spectroscopic, and other experimental evidence — is that upon fracture of asymmetrical materials, charge is separated. When the charges recombine, the electrical discharge ionizes the surrounding air, causing a flash of light. Research further suggests that crystals which display triboluminescence must lack symmetry (thus being anisotropic in order to permit charge separation) and be poor conductors. However, there are substances which break this rule, and which do not possess asymmetry, yet display triboluminescence anyway, such as hexakis(antipyrine)terbium iodide. It is thought that these materials contain impurities, which make the substance locally asymmetric.

The biological phenomenon of triboluminescence is conditioned by recombination of free radicals during mechanical activation.

Examples

In common materials

Certain household materials and substances can be seen to exhibit the property:

  • Ordinary pressure-sensitive tape ("Scotch tape") displays a glowing line where the end of the tape is being pulled away from the roll. Soviet scientists observed in 1953 that unpeeling a roll of tape in a vacuum produced X-rays. The mechanism of X-ray generation was studied further in 2008. Similar X-ray emissions have also been observed with metals.
  • Opening an envelope sealed with polymer glue generates light that can be viewed as blue flashes in darkness.
  • When sugar crystals are crushed, tiny electrical fields are created, separating positive and negative charges that then create sparks while trying to reunite. Wint-O-Green Life Savers work especially well for creating such sparks, because wintergreen oil (methyl salicylate) is fluorescent and converts ultraviolet light into blue light.

A diamond may begin to glow while being rubbed; this occasionally happens to diamonds while a facet is being ground or the diamond is being sawn during the cutting process. Diamonds may fluoresce blue or red. Some other minerals, such as quartz, are triboluminescent, emitting light when rubbed together.

Triboluminescence can occur when a Prince Rupert's Drop is shattered by a powerful force, such as a bullet. A bright flash of white light may proceed ahead of the cracking down from the head of the drop towards the tail.

Triboluminescence is a biological phenomenon observed in mechanical deformation and Contact electrification of epidermal surface of osseous and soft tissues, at chewing food, at friction in joints of vertebrae, during sexual intercourse, and during blood circulation.

Water jet abrasive cutting of ceramics (e.g. tiles) creates a yellow/orange glow at the point of impact of very high speed flow.

Chemicals notable for their triboluminescence

  • Europium tetrakis (dibenzoylmethide)triethylammonium emits particularly bright red flashes upon the destruction of its crystals.
  • Triphenylphosphinebis(pyridine)thiocyanatocopper(I) emits a reasonably strong blue light when crystals of it are fractured. This luminescence is not as extreme as the red luminescence, however is still very clearly visible to the naked eye in standard settings.
  • N-Acetylanthranilic acid emits a deep blue light when its crystals are fractured.

Fractoluminescence

Fractoluminescence is often used as a synonym for triboluminescence. It is the emission of light from the fracture (rather than rubbing) of a crystal, but fracturing often occurs with rubbing. Depending upon the atomic and molecular composition of the crystal, when the crystal fractures a charge separation can occur making one side of the fractured crystal positively charged and the other side negatively charged. Like in triboluminescence, if the charge separation results in a large enough electric potential, a discharge across the gap and through the bath gas between the interfaces can occur. The potential at which this occurs depends upon the dielectric properties of the bath gas.

EMR propagation during fracturing

The emission of electromagnetic radiation (EMR) during plastic deformation and crack propagation in metals and rocks has been studied. The EMR emissions from metals and alloys have also been explored and confirmed. Molotskii presented a dislocation mechanism for this type of EMR emission. Recently, Srilakshmi and Misra reported an additional phenomenon of secondary EMR during plastic deformation and crack propagation in uncoated and metal-coated metals and alloys.

Theory

EMR during the micro-plastic deformation and crack propagation from several metals and alloys and transient magnetic field generation during necking in ferromagnetic metals were reported by Misra (1973–75), which have been confirmed and explored by several researchers. Tudik and Valuev (1980) were able to measure the EMR frequency during tensile fracture of iron and aluminum in the region 10^14 Hz by using photomultipliers. Srilakshmi and Misra (2005a) also reported an additional phenomenon of secondary electromagnetic radiation in uncoated and metal-coated metals and alloys. If a solid material is subjected to stresses of large amplitudes, which can cause plastic deformation and fracture, emissions such as thermal, acoustic, ions, exo-emissions occur. With the discovery of new materials and advancement in instrumentation to measure effects of EMR, crack formation and fracture; the EMR emissions effect becomes important.

Generation of X-Rays

In a moderate vacuum, peeling tape generated x-rays sufficient to x-ray a human finger.

Deformation induced EMR

The study of deformation is essential for the development of new materials. Deformation in metals depends on temperature, type of stress applied, strain rate, oxidation and corrosion. Deformation induced EMR can be divided into three categories: effects in ionic crystal materials; effects in rocks and granites; and, effects in metals and alloys. EMR emission depends on the orientation of the grains in individual crystals since material properties are different in differing directions. Amplitude of EMR pulse increases as long as the crack continues to grow as new atomic bonds are broken and it leads to EMR. The Pulse starts to decay as cracking halts. Observations from experiments showed that emitted EMR signals contain mixed frequency components.

Test methods to measure EMR

Most widely tensile test method is used to characterize the mechanical properties of materials. From any complete tensile test record, one can obtain important information about the material's elastic properties, the character and extent of plastic deformation, yield and tensile strengths and toughness. The information which can be obtained from one test justifies the extensive use of tensile test in engineering materials research. Therefore, investigations of EMR emissions are mainly based on the tensile test of the specimens. From experiments, it can be shown that tensile crack formation excites more intensive EMR than shear cracking, increasing the elasticity, strength and loading rate during uniaxial loading increases amplitude. Poisson's ratio is a key parameter for EMR characterization during triaxial compression. If the Poisson's ratio is lower, it is harder for the material to strain transversally and hence higher is the probability of new fractures. Mechanism of plastic deformation is very important for safe operation of any component under dynamic conditions.

Uses and applications

This EMR can be utilized in developing sensors/smart materials. This technique can be implemented in powder metallurgy technique also. EMR is one of these emissions which accompany large deformation. If an element can be identified which gives maximum EMR response with minimum mechanical stimulus then it can be incorporated into main material and thus set new trends in the development of smart material. The deformation induced EMR can serve as a strong tool for failure detection and prevention.

Orel V.E. invented the device to measure EMR whole blood and lymphocytes in laboratory diagnostics.

Online machine learning

From Wikipedia, the free encyclopedia https://en.wikipedia.org/wiki/Online_machine_learning In computer sci...