title: "Plitvice Lakes National Park" content: river Plitvice form the Korana river. The underground configuration of the Plitvice Lakes consists of various geologic features. Generally, the whole area of Plitvice Lakes National Park can be attributed to the South-East European karst area. The typical feature of this karst area is brittle or porous rock, mostly limestone or dolomite. This configuration creates different geomorphological phenomena being referred to as dolina (sinkhole), polje, uvala, ponor, etc. In the future, the analysis of underground water courses could be an interesting field of research for speleologists. Up to now, little has been known about these unexplored courses. At first sight,


title: "Plitvice Lakes National Park" content: a lack of water in the karst region could be ascertained. However, this is only the case on the surface. The major part of natural phenomena takes place underground, where an abundance of water exists. Due to the features of limestone, many rivers drain away into the rock. Therefore, extensive underground river systems exist. Upon reaching hard rock, rivers emerge on the surface. This phenomenon of underground karst rivers (Croatian "rijeka ponornica") can also be observed at the Plitvice Lakes. Tufa sediments have been formed from the Pleistocene onwards in sinkholes or depressed areas between the surrounding mountains. Generally seen,


title: "Plitvice Lakes National Park" content: the underground of the Plitvice Lakes could be categorized into two zones. The Upper Lakes in the south predominantly consist of dolomite rock. The Lower lakes in the north predominantly consist of limestone rock. Dolomite rock is slightly harder than limestone. Though fragile upon physical influence, dolomite rock has lower water permeability properties. In contrast, limestone rock is more compact and massive, but has a higher water permeability. From an aerial perspective, significant differences between the terrain of the Upper and the Lower Plitvice Lakes can be observed. At the Upper Lakes several little lakes have formed parallel to each


title: "Plitvice Lakes National Park" content: other and a rather shallow water flow can be observed. The Lower Lakes, however, are much larger and virtually drill their path through the rock. Furthermore, there are only a few lakes at the Lower Lakes. They have formed a canyon, which continues as river Korana. On average, the annual precipitation rate at the Plitvice Lakes is . Usually, in spring and fall (autumn) the largest rain quantities are measured. The average relative air humidity is 81.8 percent. In January, the average temperature is 2.2 °C (36 °F). During the summer months of July and August, the temperature rises to


title: "Plitvice Lakes National Park" content: 17.4 °C (63 °F). The general average annual temperature is 7.9 °C (46 °F). Snow falls from November until March. Usually, the lakes are frozen during December and January. The water temperature at the springs is usually below 10 °C (50 °F). Within the rivers and lakes, the water temperature rises up to 20 °C (68 °F). The following example for different water temperatures measured on July 7, 1954 demonstrates large temperature differences within the lakes: Within lake Kozjak at the depth of 4 m a temperature of 18.9 °C (66 °F) has been measured. At a depth of 20


title: "Plitvice Lakes National Park" content: m, 5 °C (41 °F) have been measured. At 44 m depth, virtually at the bottom of the lake, a temperature of 4.1 °C (39 °F) has been measured. The lakes of Plitvice are a result of century-old processes and the sedimentation of chalk, which is abundantly available in the waters of this karst area. These sedimentations are called tufa or travertine (both are called "sedra" or "tuf" in the Croatian language, apart from many other names like "bigar" or "vapneni mačak"). A distinctive feature of the Plitvice lakes is the fact that they do not represent separated, stationary waters.


title: "Plitvice Lakes National Park" content: The lakes altogether have always been seen as one composed system of lakes. Due to constant changes it is not even possible to pursue individual analyses of single lakes. The water masses reaching the lakes at the upper or lower part of the system are continuously changing the outlook of the lakes and the surrounding landscape. They finally exit the lakes as river Korana. On the one hand, chalk tufa is being washed away partly. On the other hand, new sediments are continuously being formed. Thus, new waterfalls are being formed while others run dry. Nature itself is continuously adapting


title: "Plitvice Lakes National Park" content: to these new conditions. As a whole, the complex of lakes represents a very sensitive and labile (liable to change) ecosystem. In geological terms, the actual phenomena molding the Plitvice Lakes are quite young. The complex processes of dissolution and sedimentation of limestone require specific climatic preconditions. These have only existed since the end of the ice age about 12,000 to 15,000 years ago, according to tufa radiocarbon datings. Apart from weather and temperature factors, the water quality and other natural factors are significant for the creation of these natural phenomena, prevailing at the Plitvice Lakes. By passing through the


title: "Plitvice Lakes National Park" content: limestone underground the karst rivers dissolve chalk (calcite), which concentrates in the water. The saturation level of calcite within the frontal flows is thus very high. The water becomes significantly mineralized, super-saturated with calcium and magnesium-hydrogencarbonate. The dissolution of limestone happens through alteration processes and the effects of carbonic acid. In a natural environment, carbonic acid (HCO) is formed by the dissolution of carbon dioxide (CO) from the air or from rainwater (HO). Limestone or dolomite (CaMg(CO)) mainly consists of calcite (CaCO), which is not very soluble in water. Calcite, however, is dissolved by carbonic acid, thus creating calcium hydrogencarbonate


title: "Plitvice Lakes National Park" content: (Ca(HCO)). This is shown by the following formulas: The quantity of calcium hydrogencarbonate (also called "calcium bicarbonate") dissolved in water depends on the quantity of dissolved carbon dioxide in the water. Generally, the following could be said: The colder the water, the higher the quantity of dissolved calcium hydrogencarbonate. Depending on the conditions for the alteration processes, scientists identified limestone dissolution rates of 0.01 to 4 millimeters a year. (It is possible that by the effect of rainwater about 1 m of limestone is dissolved in about 10,000 years.) The previously mentioned mechanical and chemical dissolution processes are regularly occurring


title: "Plitvice Lakes National Park" content: natural phenomena. A unique process occurring at the Plitvice Lakes, however, is the sedimentation of water-bound chalk at certain places. With regard to other similar phenomena in the world, at Plitvice Lakes the sedimentation of chalk and the formation of tufa happens dynamically all along the watercourse and in various forms (fluviatile sedimentation). It is thus not a static phenomenon occurring at only single places. Another unique and distinctive feature are the natural factors, particularly the influences of the vegetation in the process of sedimentation. While passing the vegetation, barriers are being created by foaming water. These naturally created barriers


title: "Plitvice Lakes National Park" content: decelerate and dam the waters, thus forming lakes. At Plitvice, this constant interplay between water, air, rock and vegetation can easily be observed. The foaming water creates ever growing and impressive waterfalls. The thresholds grown up above the water level, create cataracts. About north of the lakes at the conflux of the Korana and Slunjčica rivers, right in the center of the town of Slunj, similar phenomena occur. This part of the town, called Rastoke, is often being referred to as ""the Small Lakes of Plitvice."" Measurements of carbon dioxide quantities in the water show that they correspond with continuous


title: "Plitvice Lakes National Park" content: sedimentation processes in the Plitvice Lakes area. Carbon dioxide quantities at the springs are about twenty times higher than in the atmosphere. The quantity of carbon dioxide decreases along the water route. The Plitvica river for example loses even up to 97 percent of its original quantity of carbon dioxide along its route. The sedimentation of calcium carbonate from the water occurs only at certain temperature conditions (only above 14 °C), e.g. when the water warms up or by evaporation or by another loss of carbon dioxide, additionally fostered by water plants and moss. Since sedimentation only occurs under warm,


title: "Plitvice Lakes National Park" content: humid climate conditions, these phenomena have only been occurring since the end of the last ice age. Since then, a layer of hardened tufa, also called travertine, has been formed on the limestone ground. The area of a river, in which the formation of tufa occurs, is called precipitation area. Along the Korana river for example, measured from its origins tufa is being formed only along the first 10 to , even if according to pH measurements the conditions would be favorable further down the river. At the ground of Lake Kozjak a constant yearly sedimentation of 0,8 millimeters during


title: "Plitvice Lakes National Park" content: the past 3,000 years has been ascertained. Yearly, the barriers are growing up to 13 millimeters in height. Tufa formation processes thus surpass erosion activities, which would destroy the sensitive barriers of the lakes. It is estimated that the tufa sedimentations at the ground of the lakes date back 6,000 or even 7,000 years. The precipitation of calcium carbonate, however, does not occur right at the springs of the rivers that flow into the Plitvice Lakes. For the precipitation of carbonate chalk (calcium carbonate) the water needs to reach a certain mineral saturation level. At the springs this saturation level


title: "Plitvice Lakes National Park" content: is about 1. For the precipitation, the water saturation level needs to be higher than 3. At the same time, the pH value of the water needs to be above 8,0 (slightly alkaline). Tufa barriers are the result of continuous sedimentation processes along natural thresholds. As the water flows in thin layers over thresholds, it is splashed up. This disturbs the chemical balance and causes precipitation of the carbonates, which then creates sedimentary deposits. Since the water forms larger surfaces at these places, increased quantities of carbon dioxide (CO) are released. Calcium carbonate is secreted in the form of microcrystals


title: "Plitvice Lakes National Park" content: that are deposited, eventually creating tufa sediments (CaCO). This phenomenon particularly occurs on abundantly available mosses, enabling better adherence of the crystals. In the course of time, older barriers can be flooded by rising water levels since other barriers have outgrown the older ones. 400 years ago, there were two lakes in the place of today's Kozjak lake. In the lowest third of the lake, at the level of "Matijaševića draga", a crown of an underwater barrier that is 40 m high, is stretching 4 m below the water surface. This barrier certainly formed a magnificent waterfall in the past.


title: "Plitvice Lakes National Park" content: The travertine barrier at the Kozjak bridges (at the current end of the Kozjak lake), however, grew faster. Thus, 400 years ago two lakes merged in one. That is why the greatest depths of Kozjak lake are in its lower basin (north from the little island). Mosses, algae and water plants play a major role in forming the unique landscape of the Plitvice Lakes and its tufa barriers. Up until the 21st century, it was supposed that plants extract carbon dioxide from the water for photosynthesis purposes and that in return oxygen is released, thus resulting in the sedimentation of


title: "Plitvice Lakes National Park" content: hydrogen carbonate (phytogenesis). The leading scientist arguing for this theory was Ivo Pevalek. Thanks to his efforts the Plitvice Lakes are now under national protection. Recent scientific evidence indicates that vegetation is not primarily responsible for the extraction of carbonate from the flowing water. However, plants indirectly contribute to tufa formation. For sedimentation to occur it is essential that the water be decelerated, aerated and sprayed. The mosses of the Plitvice Lakes waterfalls provide a substrate for sedimentation, generating travertine (tufa). Depending on the species found locally, various biological types of travertine can be differentiated. Photosynthesis activities of algae and


title: "Plitvice Lakes National Park" content: mosses in conjunction with the water, however, foster the crystallization of sediments due to the extraction of carbon dioxide. These effects are fostered by the millions of microscopically-small bacteria and algae that grow on such plants. They secrete mucus to which the first microcrystals of calcite adhere. The most significant plants of this kind are mosses of the species bryum and cratoneuron. The young shoots of mosses are green and soft. They are mostly without travertine, while older shoots are encrusted by a thin and fragile yellow layer, completely covered and petrified by plant-formed travertine. The mosses foster not only


title: "Plitvice Lakes National Park" content: the creation of tufa barriers, but also become part of the barrier. The moss becomes encrusted with travertine and fresh moss grows further out. First a crag is formed but later a cave roof forms under the crag. If the water continues flowing, the cave becomes progressively bigger. Older travertine is filled with fossilized algae and mosses. This type of tufa rock typical of the Plitvice Lakes is called "phytogeneous tufa." Even though the vegetation has beneficial effects for the formation of tufa, excessive concentrations of organic substances within the water impede its formation. Excessive plant cover has adverse effects


title: "Plitvice Lakes National Park" content: on mineral sedimentation. Along the course of Korana River from the Korana bridge, for example, travertine creation ends quite quickly, in spite of its supersaturation with calcium bicarbonate, as a result of the increased concentration of organic matter in the water. The park authorities have therefore begun systematic removal of excessive vegetation along the barriers. Water purity is the decisive factor for tufa formation. The water at the influx to the Plitvice Lakes is defined as pure from an analytical point of view. The Dissolved Organic Carbon (DOC) value of the water barely exceeds 2.5 mg/L at the influx to


title: "Plitvice Lakes National Park" content: the Upper Lakes (Matica). At the Lower Lakes higher concentrations are measured (5.15 mg/L). At the springs of other Croatian rivers in the karst region similar concentrations have been recorded. During the 20th century, uncontrolled tourism and water pollution caused by waste water from hotels and agricultural activities in the surrounding area have led to damage. This has led to increasing eutrophication of the lakes (increased concentrations of organic substances within the water). For the sustainable formation of tufa it is therefore imperative to protect this extremely sensitive area from excessively harmful human influence. Since 2006, it has been strictly


title: "Plitvice Lakes National Park" content: forbidden to bathe or swim in the lakes. Previously, swimming had been allowed in Lake Kozjak. With regard to plant and animal diversity, the area of the Plitvice Lakes is one of the most significant areas of Croatia, due to climatic conditions and its relatively remote location, since the lakes are at a fair distance from polluted and noisy cities and industrial plants. As a result of the low level of industrial development in this region and the early introduction of protective measures, a nearly untouched landscape has been preserved. In the partially primeval beech and fir forests various rare


title: "Plitvice Lakes National Park" content: species, such as the brown bear have survived. The Plitvice Lakes national park is heavily forested, mainly with beech, spruce, and fir trees, and features a mixture of Alpine and Mediterranean vegetation. It has a notably wide variety of plant communities, due to its range of microclimates, differing soils and varying levels of altitude. Scientists have so far identified 1,267 different types of plants belonging to the 109 species so far recorded in the area of the national park. 75 species of plants are endemic, which means that they were first defined and classified in this area of the world


title: "Plitvice Lakes National Park" content: or nearby. A great number of these plants and species are protected by law. Within the national park area 55 different species of orchids can be found. "Examples of endemic plants to be found in the national park:" "Examples of other rare plants:" The great plant diversity creates a fascinating interplay of colours that change with the seasons. The lake area is surrounded by dense forests. The national park has an area of 29,842 hectares, of which some 22,308 hectares are forests (74.75 percent), 6,957 ha are meadows (23.31 percent) in village areas and 217 ha (0.72 percent) are water


title: "Plitvice Lakes National Park" content: areas. A unique area is the forest of "Čorkova uvala", a 79.50 ha large virgin forest in the northwestern part of the park. The beech and fir trees in this area of the park are up to 700 years old. The area of the national park is home to an extremely wide variety of animal and bird species. Rare fauna such as the European brown bear, wolf, eagle, owl, lynx, wild cat, and capercaillie can be found there, along with many more common species. The wider area of the national park is one of the last areas in Europe in


title: "Plitvice Lakes National Park" content: which a great number of wild brown bears and wolves can be found. The rich fauna of the Plitvice Lakes includes some 50 species of mammals. Scientists have so far discovered 321 different kinds of butterflies, of which 76 are day-flying butterflies, and 245 are nocturnal moths. Scientists, however, estimate that up until now only about 40 percent of the whole population of butterflies has been identified. Furthermore, 12 amphibian species, as well as some species of reptiles have been recorded, including the viviparous lizard ("Lacerta vivipara"), the european green lizard ("Lacerta viridis"), the dice snake ("Natrix tessellata"), Vipera berus,


title: "Plitvice Lakes National Park" content: Vipera ammodytes and the european pond turtle ("Emys orbicularis"). As regards bird species, the Plitvice Lakes rank third among the Croatian national parks for diversity. Some 157 species have been counted, of which 70 have been recorded as breeding there. The Plitvice Lakes are also home to many kinds of bats. Recent findings list about 20 different kinds of bat species, among them the rare species of Plecotus. Among original species the brown trout ("Salmo trutta fario" and "Salmo trutta lacustris") can be mentioned. "Salmo trutta fario" is found mostly in the Upper Lakes, while "Salmo trutta lacustris" is mainly


title: "Plitvice Lakes National Park" content: found in Lake Kozjak. These species developed in different life conditions independently from each other within the various lakes. Due to the spreading growth of vegetation at the barriers, allochthonous (species that originate elsewhere and do not belong to this ecosystem) fish species spread quickly and thus endanger autochthonous trout species. Apart from the trout, common minnows "(Phoxinus phoxinus)" are also found. As a result of human interference the species salvelinus alpinus and the North American rainbow trout have been introduced to this ecosystem. Recently, even European chub "(Squalius cephalus)" and common rudd "(Scardinius erythropthalmus)", species whose emergence may be


title: "Plitvice Lakes National Park" content: attributed to climate change, have been discovered. The number of crayfish, which were almost extinct, is now again increasing. Even rare olms "(Proteus anguinus)" can be found in the karst caves of this region. Examples of some animals found in the national park: While other nature protection areas are located far away from any interference by man, the Plitvice Lakes have permanently been exposed to human influence in the course of history. The Plitvice Lakes do not represent an abandoned or lonely nature reserve. They are located along an important transport route and have always been a meeting place of


title: "Plitvice Lakes National Park" content: occidental and oriental cultural influences. Humans have inhabited the Plitvice Lakes area for thousands of years. It has been settled in turn by Illyrians, Japods, Celts, Romans, Avars, Slavs, Croats and Turks. Under Julius Caesar the region was incorporated as the province of Illyricum into the Roman Empire. The areas of the neighborly tribes of the Pannonians, the Liburnians and Dalmatians were united into the province of Dalmatia. Successively, the Ostrogoths took over the rule. After the Battle of Nedao in 454, the Ostrogoths were rewarded with a federation agreement with the Roman Empire. During the 6th century, Avars settled


title: "Plitvice Lakes National Park" content: in this region, which were accompanied by the Croats. The Croats eventually defied Avar control and settled permanently in this region. In medieval times, frequent attacks by Mongols posed a permanent threat to the settled population. The lakes formed part of the medieval kingdom of Croatia which in 1102 elected to be in personal union with Hungary. Croat rule and particularly the rule of the noble families Zrinski and Frankopan led to economic recovery in the wider area. On the remnants of an ancient settlement of the Japods and Romans a monastery was built at the lakes. Presumably, this monastery


title: "Plitvice Lakes National Park" content: belonged to the Order of Saint Paul the First Hermit (Croatian "pavlinci") or the Knights Templars. Today, only ancient wall remnants of this building (Croatian "gradina") exist. The foundation was made of travertine rock. In 1493, not far away from the Plitvice Lakes a decisive battle in Croatian history between the Austrian and Ottoman Empire took place. During the Battle of Krbava Field almost the entire Croatian nobility was killed. The Ottomans advanced far into Western lands up to Croatia and Hungary. In 1527, the Croatian Parliament elected the Habsburg monarch Ferdinand, Archduke of Austria as the new king of


title: "Plitvice Lakes National Park" content: Croatia in the hope of resources to ward of the Ottoman advance. In 1528, the area fell to the Ottomans and was retaken by the Habsburg Empire 150 years later. In 1538, king Ferdinand I ordered the establishment of the Croatian Military Frontier as a borderland of Habsburg Austria to the Ottoman Empire. The laws that prevailed in this area under special jurisdiction had formative impact on the local population for centuries. As a consequence of the establishment of this special regime, people abandoned these areas in great masses towards the West. In addition to the native Croats already inhabiting


title: "Plitvice Lakes National Park" content: the region and serving in the Austrian military, many central Europeans migrated to the region as did Serb Orthodox refugees fleeing Ottoman repression, who were given refuge in the abandoned areas in exchange for military service. The entire population of the military frontier, particularly the so-called frontiersmen, had the duty to protect this area of permanent unrest and terrible destruction. The region once also used to be called "the garden of the devil (hortus diabolus)". The Ottomans succeeded several times to gain control over the area of the Plitvice Lakes for shorter periods. In 1788, this area permanently fell back


title: "Plitvice Lakes National Park" content: under Habsburg rule. When the Ottoman threat subsided, the Military Frontier was reverted to the civilian control of the Croatian viceroy (Ban). The area then formed part of Banovina of Croatia within the Kingdom of Yugoslavia and then part of the Socialist Republic of Croatia within the Socialist Yugoslavia. Today, it is part of the Republic of Croatia. In 1805, another major rule change happened, which created an economic upturn. Dalmatia and Lika fell under the rule of Napoleon, who founded the Illyrian provinces. After 1814, the area of the Plitvice Lakes came back under Habsburg rule. Since 1850, only


title: "Plitvice Lakes National Park" content: professional soldiers served in the Military Frontier. This was also a time of national awakening in Croatia. In 1871, the famous Croatian politician Eugen Kvaternik was killed north of the lakes at Rakovica. The Croatian rebellion was put down by Austrian authorities. Kvaternik propagated the rule of law and argued for the liberation from Austrian-Hungarian predominance. In former times, the local population lacked the proper comprehension of the natural values of the Plitvice Lakes. Farmers had to focus on securing the daily bread for their families in these dour times, which was accompanied by grave changes to nature. For example,


title: "Plitvice Lakes National Park" content: smaller lakes were filled up with earth or people adapted the flow of the rivers to their individual needs. Already in 1861, an accommodation for travelers was erected at "Velika Poljana". The local population called this accommodation the "Emperor's house", since imperial military officers used to reside in this location. For the visit of Crown Princess Stéphanie of Belgium, the wife of Crown Prince Rudolf of Austria in 1888, the Plitvice Lakes and their surroundings were arranged for tourist purposes for the first time in history. Two paths still bear the names of the daughters of the Emperor Franz Joseph:


title: "Plitvice Lakes National Park" content: ""Stephanie's Path" (Croatian Štefanijin put)" and ""Dorothea's Path" ()". In 1890, the tradesman Ante Devčić from Senj built the first hotel with a restaurant at Prošćansko jezero. However, he exaggerated in his efforts and also caused partly irreparable damage on the nature. For example, he constructed canals across the travertine barriers for his saw mill that are visible even today. At the same place, today called "Labudovac", Gustav Janeček, a Czech from Zagreb, built a restaurant and accommodation. In 1893, Janeček founded the "Society for the preservation of the Plitvice Lakes" (Croatian "Društvo za uređenje i poljepšanje Plitvičkih jezera"), with


title: "Plitvice Lakes National Park" content: the aim of preserving the lakes after all negative influence they have been exposed to. The society also built a hotel at the lakes. In 1898, one of the waterfalls was named after Croatian opera singer Milka Ternina. She gave money from concerts to preserve the park, upgrade tracks and build pathways. During the First World War, the Croatian parliament in Zagreb passed the "Law on the Protection of the Plitvice Lakes" in 1916. However, this law did not contain adequate measures of protection and is thus not regarded as official founding declaration of the national park. During the following


title: "Plitvice Lakes National Park" content: decades, preservation efforts reached a deadlock. However, some very significant meetings took place at the Plitvice Lakes during the Second World War, as for example the first secret regional conference of the League of Communists of Croatia (Croatian: "Savez komunista Hrvatske, SKH") in 1940. On June 14, 1943 one of the founding sessions of the National Anti-Fascist Council of the People's Liberation of Croatia (ZAVNOH) took place at Plitvice Lakes. This was the highest governing organ of the anti-fascist movement in Croatia during World War II. The former Secretary General of the Communist Party of Croatia, Rade Končar, was born


title: "Plitvice Lakes National Park" content: in Končarev Kraj at the Plitvice Lakes in 1911. After the end of the Second World War, the unique natural phenomena of this area were acknowledged permanently. On April 8, 1949, the Plitvice Lakes were declared as a national park area and rigorous nature protection measures were established. During the 1960s, a modern road connection to the Plitvice Lakes was constructed, which led to increasing traffic volumes. During these years, several hotels and other objects were erected according to innovative plans of Croatian architects. However, some buildings that would fit current standards were already demolished during the 1980s by the


title: "Plitvice Lakes National Park" content: Communist authorities. Between 1962 and 1968, many Western film productions of Karl May novels have been shot at the Plitvice Lakes (mainly German-French-Yugoslav cooperations). The most successful film of this series, "Treasure of the Silver Lake" was also produced at some locations within the national park. (Lake "Kaluđerovac" served as scenery for the Silver Lake.) During the 1970s, detailed land registers of the national park were recorded. The park was inscribed on the UNESCO World Natural Heritage List in 1979 in recognition of its "outstanding natural beauty, and the undisturbed production of travertine (tufa) through chemical and biological action". During


title: "Plitvice Lakes National Park" content: the 1980s, tourism was booming in Yugoslavia. Plitvice Lakes National Park soon became one of Yugoslavia's most popular tourist attractions. The beginning of the 1990s, however, marked another great turning point in the history of this national park. In March 1991 it became the scene of the Plitvice Lakes incident (also called the "Plitvice Bloody Easter"), the first armed confrontation of the Croatian War of Independence that resulted in fatalities. The park was held by local Serb rebels backed by Slobodan Milošević and the Yugoslav People's Army (JNA) as part of the self-proclaimed "Republic of Serbian Krajina" during the conflict


title: "Plitvice Lakes National Park" content: and suffered some damage in the process, with hotels and other facilities being used as barracks. During the period under the control of Serb forces loyal to Belgrade, Croats were ethnically cleansed from the region systematically. The region was retaken by the Croatian Army in August 1995 during Operation Storm, and majority of Serb population was expelled. During the war from 1991 until 1995, many buildings in the national park were destroyed or burnt down. Due to the apparent risk of mines, the park was even put on the UNESCO List of World Heritage in Danger during the war years.


title: "Plitvice Lakes National Park" content: After the war, the Plitvice Lakes were among the first areas to be cleared of mines and renovated. In 1998, the national park was removed from the List of World Heritage in Danger. In 2000, the national park was expanded by a further in order to protect the underground tributary streams. Within the national park continuous scientific research projects are being carried out. The national park administration currently endeavors to introduce new, progressive protection measures. There is a proposal to replace the wooden bridges and paths by floating pontoon bridges. The existing wooden paths are anchored within the travertine sediments,


title: "Plitvice Lakes National Park" content: creating the danger of seepage and cracks of the weak travertine. The Plitvice Lakes are today one of the most frequently visited tourist attractions in Croatia. Due to their high natural, cultural and tourist significance, they have become a motor for the local economy. About 1,000,000 visitors per year greatly contribute to the economic development of the wider region. Due to high tourism and illegal construction around lakes, with faecal waste flowing down to surrounding woods and lakes without any treatment, the water in the lakes is polluted and no longer drinkable. In its current state, UNESCO threatens to remove


title: "Plitvice Lakes National Park" content: the park's status as a World Natural Heritage site. The preservation of old customs and traditions is of high significance for the local population. The local culture has also been detected as an important factor for tourism. As regards architecture, the region of Lika is well known for its low wooden houses with roofs made of rye straw or shingles. Many features of the ancient living style are mirrored in local costumes. They tell a lot about regional affiliations or social standings of those who have worn those costumes. Under French rule, men were allowed to wear their costumes during


title: "Plitvice Lakes National Park" content: military service. Up until the 20th century, social gatherings during the winter months, when no agricultural activities could be performed, called "prelo" represented a typical tradition of this region. These gatherings served for the joint production of textiles or butter or for the further processing of harvest products (production of flour, etc.). These activities used to be accompanied by drinks and dances, particularly during the evenings. A well-known dance of this region is the round dance (Croatian "kolo"). Local cuisine consists of drinks, such as Slivovitz (Croatian "šljivovica"), wine and coffee or dishes, such as soft cheese (Croatian "vrhnje"), polenta,


title: "Plitvice Lakes National Park" content: pršut, paprika sausage, roasted suckling pig (Croatian: "odojak") or lamb (Croatian: "janjetina"). Each of the Plitvice Lakes has a story or legend to tell. Most lake names stem from true events. Comparable phenomena to those prevailing at the Plitvice Lakes exist at Rastoke (Slunj), at the Krka National Park or at the rivers Una and the Pliva in Bosnia and Herzegovina. The Band-e Amir lakes within the Hindu Kush mountain range form a similar system of lakes and dams, though diverging tufa formation processes prevail. Calc-sinter formation processes that have not emerged along a river flow can be observed at


title: "Plitvice Lakes National Park" content: the Mammoth Hot Springs within Yellowstone National Park (USA) or at Pamukkale in Turkey. Jiuzhaigou is a nature reserve and national park located in the north of Sichuan, China. Also inscribed by UNESCO as a World Heritage Site, its landscape of cascading lakes is made up of high-altitude karsts shaped by glacial, hydrological and tectonic activity.The area around Ocho Rios Jamaica is another region famous for its calc-sinter rivers. Most popular, particularly with cruise ships, is Dunn's River Falls. Plitvice Lakes National Park Plitvice Lakes National Park (, colloquial "Plitvice", ) is one of the oldest and largest national parks


title: Autopsy content: it back together. The term "autopsy" derives from the Ancient Greek αὐτοψία "autopsia", "to see for oneself", derived from αὐτός ("autos", "oneself") and ὄψις ("opsis", "sight, view"). The word “autopsy” has been used since around the 17th century, it refers to the examination of inside the dead human body to discover diseases and cause of death. The principal aims of an autopsy is to determine the cause of death, the state of health of the person before he or she died, and whether any medical diagnosis and treatment before death was appropriate. In most Western countries the number of autopsies


title: WNET content: petition, stating that WNET's action would lead to the shows being marginalized by PBS affiliates nationwide and have a severe effect on cutting edge documentary filmmaking. Among the prominent opponents of rescheduling "POV" and "Independent Lens" were filmmakers Alex Gibney and Laura Poitras, who had campaigned against a similar move by WNET in 2012. TV producer Norman Lear wrote an op-ed in "The New York Times" accusing WNET and PBS of a ratings-chase that "could devastate independent documentary film making." He criticized the broadcaster for "threatening, for the second time in four years, to downgrade documentaries, which are at the


title: "Citizens Bank Park" content: Citizens Bank Park Citizens Bank Park is a baseball park located in Philadelphia, Pennsylvania within the South Philadelphia Sports Complex. It is the home of the Philadelphia Phillies, the city's Major League Baseball (MLB) franchise. It opened April 3, 2004, and hosted its first regular-season baseball game on April 12 of the same year, with the Phillies losing to the Cincinnati Reds, 4–1. The ballpark was built to replace the now-demolished Veterans Stadium (a football/baseball multipurpose facility), and features a natural grass and dirt playing field as well as a number of Philadelphia-style food stands, including several which serve cheesesteaks,


title: "Citizens Bank Park" content: hoagies and other regional specialties. The ballpark lies on the northeast corner of the Sports Complex, which includes Lincoln Financial Field, Wells Fargo Center, and Xfinity Live!. The stadium's capacity is 43,305 seats. In 1999, the Phillies and the Philadelphia Eagles of the National Football League joined their Western Pennsylvania counterparts, the Pittsburgh Pirates and the Pittsburgh Steelers, in making requests to replace both Veterans Stadium and Three Rivers Stadium in Pittsburgh with separate stadiums. Pressure for new Philadelphia stadiums increased after a railing collapsed at The Vet during the 1998 Army–Navy Game, injuring eight cadets. The Pirates threatened to


title: "Citizens Bank Park" content: leave Pittsburgh in 1997, which helped convince the legislature to approve funding for the four proposed stadiums. While Allegheny County and the City of Pittsburgh approved the pacts swiftly, due to plans already being in place at the time of legislative approval, debate within Philadelphia's city leadership carried on as Pittsburgh opened their stadiums (PNC Park for the Pirates and Heinz Field for the Steelers) in 2001. The Eagles agreed to a site slightly southeast of Veterans Stadium, which would become Lincoln Financial Field. The Eagles' stadium was built on the site of an old food warehouse and celebrated its


title: "Citizens Bank Park" content: grand opening in August 2003. The Phillies originally wanted a downtown ballpark similar to Baltimore, Denver, Cincinnati, Cleveland, Detroit and San Francisco. Various locations were proposed, initially at Broad and Spring Garden streets, Spring Garden and Delaware Avenue and next to 30th Street Station, where the main post office was located. The team and the city announced that the site would be at 13th and Vine streets in Chinatown, just north of Interstate 676, within walking distance of Center City. There was considerable support for a downtown ball park from business and labor and the city at large. However, Chinatown


title: "Citizens Bank Park" content: residents protested, fearing a new ballpark would destroy their neighborhood. The City and team eventually settled on building at the South Philadelphia Sports Complex, on the site of an old food warehouse much like Lincoln Financial Field. In the years that followed, residents, fans and owner Bill Giles expressed regret that the new ball park was not located in Center City. Regardless of location, the team set records in 2010 for attendance (3,647,249 fans, averaging 45,028) and sellouts (81), extending a streak dating back to July of 2009 to 123 straight sellouts. The new stadium was designed by EwingCole's Stanley


title: "Citizens Bank Park" content: Cole, who was the stadium's chief architect. The unveiling of the park and ground breaking ceremonies were on June 28, 2001. Following the game that evening, the location of the left-field foul pole was unveiled at the outset of the team's annual 4 July fireworks display. On June 17, 2003, Citizens Bank agreed with the team to a 25-year, US $95 million deal for naming rights and advertising on telecasts, radio broadcasts, publications and inside the facility. The ballpark was officially topped off on August 12, 2003, and opened in April 2004. Shortly after the park opened in 2004, the


title: "Citizens Bank Park" content: bullpens were reassigned so the Phillies' pitchers used the lower pen and visitors use the upper pen. This was done to give Phillies' pitchers a better view of the game and to protect them from heckling by rowdy fans. However, the team forgot to rewire the bullpen phones after the bullpens were reassigned; so during the first game, the dugout coaches had to communicate with the bullpens by hand signals. In its first years, Citizens Bank Park allowed 218 home runs in 2004 and 201 in 2005. More than half of those home runs were to left-field. Following the 2005


title: "Citizens Bank Park" content: season, the left-field wall was moved back . Even with these modifications, the park has a reputation as one of the most hitter-friendly parks in baseball. In 2009, it gave up 149 home runs, the most in the National League and second in the majors behind only the new Yankee Stadium, but has been neutral since, with a .997 park factor in 2011. Behind center field is Ashburn Alley, named after Phillies Hall of Fame center fielder Richie Ashburn, who played for the team from 1948 to 1959 and was a Phillies broadcaster from 1963 until his death in 1997.


title: "Citizens Bank Park" content: It is seen by Phillies fans as a compromise between the Phillies and their fans, many of whom wanted Citizens Bank Park named in honor of Ashburn. Ashburn Alley is named for the slightly-overgrown grass which bordered the third base line at Shibe Park where Ashburn was famous for laying down bunts that stayed fair. The new Ashburn Alley, located near Ashburn's defensive position, is a walkway featuring restaurants, games and memorabilia from Phillies history. Ashburn Alley also features a memorabilia shop and a large bronze statue of Ashburn directly behind center field, as well as the U.S. flag, the


title: "Citizens Bank Park" content: flags of the Commonwealth of Pennsylvania and the City of Philadelphia, a POW/MIA flag and the flags from the Phillies' championships (below). Features of the Alley are: In 2004 and 2005, organist Paul Richardson performed from Ashburn Alley, as Citizens Bank Park was built without an organ booth. Besides the Richie Ashburn statue in Ashburn Alley, statues of three other famous Phillies — Robin Roberts (at the First Base Gate), Mike Schmidt (at the Third Base Gate) and Steve Carlton (at the Left Field Gate) — ring the outside of the facility. Each of the statues were made by local


title: "Citizens Bank Park" content: sculptor Zenos Frudakis. Other art found throughout the park includes tile mosaics, murals and terrazzo floors with outlined images of famous players in Phillies history. In April 2011, the Phillies accepted a gift of a fan-underwritten bronze statue of legendary broadcaster Harry Kalas. Created by noted local sculptor Lawrence Nowlan, it was placed behind Section 141, near the restaurant that bears Kalas' name, after a dedication held on August 16, 2011 prior to that night's game against the Arizona Diamondbacks. The statue was unveiled two days later than originally scheduled (the originally-scheduled date is on a plaque on the ground


title: "Citizens Bank Park" content: below the statue) because of a rained-out game between the Phillies and the Washington Nationals. The Philadelphia Phillies are the first Major League Baseball team to join the Environmental Protection Agency's Green Power Partnership Program which motivates organizations across the world to purchase green power in order to minimize environmental impact. The Phillies announced on April 30, 2008 that their home field, Citizens Bank Park, will be powered with 20 million kilowatt-hours (kWh) of green energy purchased in Green-e Energy Certified Renewable Certificates (RECs). The EPA stated that this purchase holds the record in professional sports for the largest purchase


title: "Citizens Bank Park" content: of 100% renewable energy. The Phillies are among the top three purchasers of green power in Philadelphia, and the executive director of the Center for Resource Solutions, Arthur O'Donnell, wants "other clubs to take their lead." Aramark Corporation is the Phillies' food and beverage provider at Citizens Bank Park and they are taking major actions in improving the environmental impact of the Phillies' stadium. Glass, cardboard and plastics used during game day are recycled; frying oil is being recycled to produce biodiesel fuel, and biodegradable, recyclable, and compostable products, serviceware, and plastics have been introduced. On January 2, 2012, Citizens


title: "Citizens Bank Park" content: Bank Park hosted the fifth annual NHL Winter Classic between the long time division rivals New York Rangers and Philadelphia Flyers before an SRO crowd of 46,967. The game, which was televised throughout the United States and Canada by NBC and CBC respectively, was won by the Rangers, 3–2. Two days earlier on New Year's Eve, 45,667 had attended an alumni game played between teams made up of former who had retired from the NHL between the 1970s and 2011 of which eight (four on each team) were also members of the Hockey Hall of Fame. The Flyers' starting goalie


title: "Citizens Bank Park" content: for the game, which was won by the Flyers alumni, 3-1, was Hall of Famer Bernie Parent. He had made his first since his playing career ended prematurely due to an eye injury suffered during a game against the Rangers played at the neighboring (although since demolished) Spectrum in February 1979. Four days after the 2012 NHL Winter Classic game, a third sell out crowd of 45,663 filled the Park on January 6 to watch the Flyers' AHL farm team, the Adirondack Phantoms, defeat the Hershey Bears, 4-3, in overtime. That crowd exceeded by a factor of more than two


title: "Citizens Bank Park" content: the previous largest gathering (21,673) to ever attend an AHL game since the league was established in 1936. With the normal 43,651 baseball seating capacity of the Park having been increased by more than 3,000 with the installation of built over the bullpen area in center field, the trio of outdoor hockey games drew a combined total of 138,296 over the week of Winter Classic events. The first concert at the park was Jimmy Buffett & The Coral Reefer Band on August 25, 2005; they returned on June 14, 2008. The Eagles, The Dixie Chicks and Keith Urban were scheduled


title: "Citizens Bank Park" content: to perform on June 14, 2010, but the show was cancelled. Other performers who have played at the park include Billy Joel and Elton John in a duet concert, Bon Jovi and The Police. Due to the City of Philadelphia's smoking ban, smoking is no longer allowed anywhere within the stadium as of the 2018 season. Dan Baker, public address announcer for the Phillies since 1972, continues to introduce the players. During each player's first at-bat, Baker, in an excited voice, says, "Now batting for the Phillies, number (#), (position), (player's name)". For example, a first at-bat introduction would have


title: "Citizens Bank Park" content: Baker say, "Now batting for the Phillies, number 11, shortstop Jimmy Rollins!" During subsequent at-bats, players are only announced by their position and name, for example, "Phillies first baseman, Ryan Howard!" Baker only uses the city of the opposing team when he announces their players rather than the team nickname, for example, "Now batting for Atlanta, number ten, third baseman Chipper Jones", and makes the announcement in a more-subdued tone. In 2004 and 2005, Citizens Bank Park installed Daktronics video and message displays in the park. One of the largest incandescent displays in Major League Baseball was installed in left


title: "Citizens Bank Park" content: field that was used as a scoreboard and for giving statistics. There are also out-of-town field-level displays installed in the park that measure approximately 10 feet high by 25 feet wide. During the 2010–2011 offseason, the Phillies replaced their incandescent scoreboard with a new HD scoreboard that cost $10 million. The new screen measures high and wide, which nearly triples the size of the old screen, and is the second largest HD screen in the National League, after the San Diego Padres' PETCO Park screen (61 ft. high and 124 ft. wide). The food at CBP was named as Best


title: "Citizens Bank Park" content: Ballpark Food in a survey of Food Network viewers in the first annual Food Network Awards which first aired on April 22, 2007. On August 14, 2007, it was announced that Citizens Bank Park was voted #1 by PETA as America's most vegetarian-friendly ballpark, which was repeated in 2008, 2009, 2010, and 2012. Citizens Bank Park Citizens Bank Park is a baseball park located in Philadelphia, Pennsylvania within the South Philadelphia Sports Complex. It is the home of the Philadelphia Phillies, the city's Major League Baseball (MLB) franchise. It opened April 3, 2004, and hosted its first regular-season baseball game


title: "Mercy Otis Warren" content: This set her apart from other girls, and most likely paved the way for her to break the traditional gender roles of her time. Her father also had unconventional views of his daughter's education, as he fully supported her endeavors, which was extremely unusual for the 18th century. James Otis attended Harvard College and became a noted patriot and lawyer. What little of his correspondence with Mercy survives suggests that James encouraged Mercy's academic and literary efforts, treating her as an intellectual equal and confidante. She married James Warren on November 14, 1754. After settling in Plymouth, James inherited his


title: "Bishop Auckland" content: house into a castle. The grounds of the castle were noted as being large enough to contain 16000 men ahead of the Battle of Neville's Cross in 1346. Between 1283 and 1310, Bek was also responsible for ordering the replacement of the collegiate church established in 1183 with the Church of St Andrew that stands in South Church today, together with accommodation for the canons; the building known today as the East Deanery. The collegiate church also appears to have supported a school. The collegiate church was re-organised under Bishop Langley in 1428 and at some point in the same


title: "Hurricane Connie" content: 17 near New Bern. Throughout North Carolina, the hurricane caused about $40 million in damage, of which about 75% was from crop damage. There were 27 deaths in the state related to Connie, including traffic deaths, drownings, people in damaged buildings, and electrocutions. Damage was minimal in Myrtle Beach, South Carolina. Hurricane-force winds extended into Virginia. In the state, severe river flooding was reported from the coast, inland to Richmond, which caused localized damage. Ten stations in the state, and sixteen in neighboring Maryland, reached the highest stage on record. As Connie progressed northward, it continued to drop significant amounts


title: "Steve Bartman incident" content: Alou slammed his glove down in frustration and shouted at several fans. The Cubs, in particular Alou and Prior, argued for fan interference, but umpire Mike Everitt ruled there was no interference because the ball had broken the plane of the wall separating the field of play from the stands and entered the stands. Cubs manager Dusty Baker did not see the play as it happened, because the curvature of the Cubs dugout blocked his view. Everitt's ruling has been heavily scrutinized over the years. For example, the authors of "Mad Ball: The Bartman Play" argue that photographs show Bartman's


title: "Steve Bartman incident" content: important thing," said Epstein. In 2012, former Cubs player Doug Glanville said, "[I]t was easy to look at Steve Bartman [...] But that was not the whole story by a long shot." He argued that the Cubs lost the momentum of the series when Marlins ace Josh Beckett shut down the Cubs in Game 5. Glanville drew parallels between that game and Barry Zito's game-winning performance in Game 5 of the 2012 NLCS. Through spokesman Frank Murtha, Bartman congratulated the Cubs in their World Series championship victory over the Cleveland Indians. Murtha did not state if Bartman watched the series,


title: Wednesbury content: on Thomas Telford's London to Holyhead road, built in the early 19th century. The section between Wednesbury and Moxley was widened in 1997 to form a dual carriageway, completing the Black Country Spine Road that had been in development since 1995 when the route between Wednesbury and West Bromwich had opened, along with a one-mile route to the north of Moxley linking with the Black Country Route. The original plan was for a completely new route between Wednesbury and Moxley, but this was abandoned as part of cost-cutting measures, as were the planned grade-separated junctions, which were abandoned in favour


title: "1921 Canadian federal election" content: Minister Arthur Meighen. During the war, the Conservatives had united with the pro-conscription Liberal-Unionists and formed a Union government. A number of Members of Parliament (MPs), mostly Quebecers, stayed loyal to Sir Wilfrid Laurier, however, and they maintained their independence. When Laurier died, he was replaced as leader by the Ontarian Mackenzie King. After the 1919 federal budget, a number of western unionist MPs, who were former Liberals, left the Union government in protest against high tariffs on farm products imposed by the budget. Led by Thomas Alexander Crerar, the group became known as the Progressive Party. Also running were


title: Tiananmen content: Tiananmen The Tiananmen or Tian'anmen (), or the Gate of Heavenly Peace, is a monumental gate in the centre of Beijing, widely used as a national symbol of China. First built during the Ming dynasty in 1420, Tiananmen was the entrance to the Imperial City, within which the Forbidden City was located. Tiananmen is located to the north of Tiananmen Square, separated from the plaza by Chang'an Avenue. The Chinese name of the gate (/), is made up of the Chinese characters for "heaven," "peace" and "gate" respectively, which is why the name is conventionally translated as "Gate of Heavenly


title: Tiananmen content: Peace". However, this translation is somewhat misleading, since the Chinese name is derived from the much longer phrase "receiving the mandate from heaven, and pacifying the dynasty." (). The Manchu translation, "Abkai elhe obure duka", lies closer to the original meaning of the gate and can be literally translated as the "Gate of Heavenly Peacemaking." The gate had a counterpart in the northern end of the imperial city called Di'anmen (, Dì'ānmén; Manchu: "Na i elhe obure duka"), which may be roughly translated as the "Gate of Earthly Peacemaking." The gate was originally named Chengtianmen (), or "Gate of Accepting


title: Tiananmen content: Heavenly Mandate", and it has been destroyed and rebuilt several times. The original building was first constructed in 1420 and was based on a gate of an imperial building in Nanjing with the same name and hence inherited the name "Chengtianmen". The gate was damaged by lightning in July, 1457, and was completely burnt down. In 1465, the Chenghua Emperor of the Ming dynasty ordered Zi Gui (), the Minister of Works, to rebuild the gate, and the design was changed from the original paifang form to the gatehouse that is seen today. It suffered another blow in the war


title: Tiananmen content: at the end of the Ming dynasty, when in 1644 the gate was burnt down by rebels led by Li Zicheng. Following the establishment of the Qing dynasty and the Manchu conquest of China proper, the gate was once again rebuilt, beginning in 1645, and was given its present name upon completion in 1651. The gate was reconstructed again between 1969 and 1970. The gate as it stood was by then 300 years old, and had badly deteriorated, partly due to heavy usage in the 1950s and 1960s. As the gate was a national symbol, Zhou Enlai ordered that the


title: Tiananmen content: rebuilding was to be kept secret. The whole gate was covered in scaffolding, and the project was officially called a "renovation". The rebuilding aimed to leave the gate's external appearance unchanged while making it more resistant to earthquakes and featuring modern facilities such as an elevator, water supply and heating system. The building is long, wide and high. Like other official buildings of the empire, the gate has unique imperial roof decorations. In front of the gate are two lions standing in front of the gate and two more guarding the bridges. In Chinese culture, lions are believed to protect


title: Tiananmen content: humans from evil spirits. Two stone columns, called huabiao, each with an animal ("hou") on top of it, also stand in front of the gate. Originally, these installations were designed for commoners to address their grievances by writing or sticking up petitions on the columns. However, the examples in front of the Imperial City were purely decorative and instead connoted the majesty of the imperial government. The western and eastern walls have giant placards; the left one reads "Long Live the People's Republic of China" (), while the right one reads "Long Live the Great Unity of the World's Peoples".


title: Tiananmen content: The right placard used to read "Long Live the Central People's Government" on the founding ceremony of the PRC, but after the ceremony it was changed to "Long Live the Great Unity of the World's Peoples" () Former names (). Both placards were changed to use simplified Chinese instead of traditional Chinese characters in 1964. The phrasing has significant symbolic meaning, as the phrase used for "long live", like the Imperial City itself, was traditionally reserved for Emperors of China, but is now available to the common people. The reviewing stands in the foreground are used on International Workers Day


title: Tiananmen content: (May Day) and on the National Day (October 1) of the People's Republic of China. In front of the stands is the Imperial City's moat, still filled with water but now containing decorative illuminated fountains. In ancient times, the Tiananmen was among the most important gates encountered when entering Beijing's Imperial City along with the Qianmen, the Gate of China. Proceeding further inward, the next gate is the 'Upright Gate', identical in design to the Tian'anmen; behind it is the southern entrance of the Forbidden City itself, known as the Meridian Gate. Because of the gate's position at the front


title: Tiananmen content: of the Imperial City, and historical events that have taken place on Tiananmen Square, the gate has great political significance. In 1925, when China was ruled by the Nationalist government, a large portrait of Sun Yat-sen was hung at the gate after his death. In 1945, to celebrate the victory over Japan, Chiang Kai-shek's portrait was hung. On July 7, 1949, pictures of Zhu De and Mao Zedong were hung to commemorate the Second Sino-Japanese War. Since then, from the founding date of the People's Republic of China, a portrait of Mao has been hung at the square on October


title: Tiananmen content: 1. Each year the old portrait is replaced before October 1, the anniversary of the founding of the People's Republic of China. However, on certain occasions the picture has been different. For example, on March 9, 1953, a picture of Joseph Stalin was put up due to his death. In 2011 Alexander Pann Han-tang, chairman of the Asia Pacific Taiwan Federation of Industry and Commerce, and a close friend of Taiwanese president Ma Ying-jeou, proposed that the picture of Sun Yat-sen be displayed at Tiananmen Square instead for the 100th anniversary of the founding of the Republic of China. However


title: Tiananmen content: this proposal was rejected. The portrait weighs 1.5 tonnes and is generally replaced by a spare when it is vandalised. In 1989, three dissidents, including Yu Dongyue, attacked the portrait with eggs during the Tiananmen Square protests of 1989. Yu was sent to prison and was not released until 17 years later in 2006. On May 12, 2007 the portrait of Mao caught fire. A 35-year-old unemployed man from Urumqi was arrested for the incident. About 15% of the portrait was damaged, and had to be repaired later. On April 5, 2010, a protester threw ink in a plastic bottle


title: Tiananmen content: and hit a wall near the portrait. He was then arrested. Due to its historical significance, Tiananmen is featured on the National Emblem of the People's Republic of China. It has also been featured in the designs of stamps and coins issued by the People's Republic of China. Tiananmen is open to the public each day of the week from 8:30 a.m. to 5:00 p.m. Line 1 of the Beijing Subway has stops at Tiananmen West and Tiananmen East, on either side of Tiananmen. City buses 1, 2, 5, 52, 59, 82, 99, 120, 126, 1, 2, 1, 2, 17


title: Tiananmen content: stop near Tiananmen. Tiananmen The Tiananmen or Tian'anmen (), or the Gate of Heavenly Peace, is a monumental gate in the centre of Beijing, widely used as a national symbol of China. First built during the Ming dynasty in 1420, Tiananmen was the entrance to the Imperial City, within which the Forbidden City was located. Tiananmen is located to the north of Tiananmen Square, separated from the plaza by Chang'an Avenue. The Chinese name of the gate (/), is made up of the Chinese characters for "heaven," "peace" and "gate" respectively, which is why the name is conventionally translated as


title: "Electrolytic capacitor" content: Electrolytic capacitor An electrolytic capacitor (abbreviated e-cap) is a polarized capacitor whose anode or positive plate is made of a metal that forms an insulating oxide layer through anodization. This oxide layer acts as the dielectric of the capacitor. A solid, liquid, or gel electrolyte covers the surface of this oxide layer, serving as the (cathode) or negative plate of the capacitor. Due to their very thin dielectric oxide layer and enlarged anode surface, electrolytic capacitors have a much higher capacitance-voltage (CV) product per unit volume compared to ceramic capacitors or film capacitors, and so can have large capacitance values.


title: "Electrolytic capacitor" content: There are three families of electrolytic capacitor: aluminum electrolytic capacitors, tantalum electrolytic capacitors, and niobium electrolytic capacitors. The large capacitance of electrolytic capacitors makes them particularly suitable for passing or bypassing low-frequency signals, and for storing large amounts of energy. They are widely used for decoupling or noise filtering in power supplies and DC link circuits for variable-frequency drives, for coupling signals between amplifier stages, and storing energy as in a flashlamp. Electrolytic capacitors are polarized components due to their asymmetrical construction, and must be operated with a higher voltage (ie, more positive) on the anode than on the cathode


title: "Electrolytic capacitor" content: at all times. For this reason the anode terminal is marked with a plus sign and the cathode with a minus sign. Applying a reverse polarity voltage, or a voltage exceeding the maximum rated working voltage of as little as 1 or 1.5 volts, can destroy the dielectric and thus the capacitor. The failure of electrolytic capacitors can be hazardous, resulting in an explosion or fire. Bipolar electrolytic capacitors which may be operated with either polarity are also made, using special constructions with two anodes connected in series. As to the basic construction principles of electrolytic capacitors, there are three


title: "Electrolytic capacitor" content: different types: aluminum, tantalum, and niobium capacitors. Each of these three capacitor families uses non-solid and solid manganese dioxide or solid polymer electrolytes, so a great spread of different combinations of anode material and solid or non-solid electrolytes is available. Like other conventional capacitors, electrolytic capacitors store the electric energy statically by charge separation in an electric field in the dielectric oxide layer between two electrodes. The non-solid or solid electrolyte in principle is the cathode, which thus forms the second electrode of the capacitor. This and the storage principle distinguish them from electrochemical capacitors or supercapacitors, in which the


title: "Electrolytic capacitor" content: electrolyte generally is the ionic conductive connection between two electrodes and the storage occurs with statically double-layer capacitance and electrochemical pseudocapacitance. Electrolytic capacitors use a chemical feature of some special metals, previously called “valve metals”, which on contact with a particular electrolyte form a very thin insulating oxide layer on their surface by anodic oxidation which can function as a dielectric. There are three different anode metals in use for electrolytic capacitors: To increase their capacitance per unit volume, all anode materials are either etched or sintered and have a rough surface structure with a much higher surface area compared


title: "Electrolytic capacitor" content: to a smooth surface of the same area or the same volume. By applying a positive voltage to the above-mentioned anode material in an electrolytic bath an oxide barrier layer with a thickness corresponding to the applied voltage will be formed (formation). This oxide layer acts as dielectric in an electrolytic capacitor. The properties of this oxide layers are given in the following table: After forming a dielectric oxide on the rough anode structure, a counter electrode has to match the rough insulating oxide surface. This is accomplished by the electrolyte, which acts as the cathode electrode of an electrolytic


title: "Electrolytic capacitor" content: capacitor. There are many different electrolytes in use. Generally they are distinguished into two species, “non-solid” and “solid” electrolytes. As a liquid medium which has ion conductivity caused by moving ions, non-solid electrolytes can easily fit the rough structures. Solid electrolytes which have electron conductivity can fit the rough structures with the help of special chemical processes like pyrolysis for manganese dioxide or polymerization for conducting polymers. Comparing the permittivities of the different oxide materials it is seen that tantalum pentoxide has a permittivity approximately three times higher than aluminum oxide. Tantalum electrolytic capacitors of a given CV value theoretically


title: "Electrolytic capacitor" content: are therefore smaller than aluminium electrolytic capacitors. In practice different safety margins to reach reliable components makes a comparison difficult. The anodically generated insulating oxide layer is destroyed if the polarity of the applied voltage changes. Electrolytic capacitors are based on the principle of a "plate capacitor" whose capacitance increases with larger electrode area A, higher dielectric permittivity ε, and thinner dielectric (d). The dielectric thickness of electrolytic capacitors is very small, in the range of nanometers per volt. On the other hand, the voltage strengths of these oxide layers are quite high. With this very thin dielectric oxide layer


title: "Electrolytic capacitor" content: combined with a sufficiently high dielectric strength the electrolytic capacitors can achieve a high volumetric capacitance. This is one reason for the high capacitance values of electrolytic capacitors compared to conventional capacitors. All etched or sintered anodes have a much higher surface area compared to a smooth surface of the same area or the same volume. That increases the capacitance value, depending on the rated voltage, by a factor of up to 200 for non-solid aluminium electrolytic capacitors as well as for solid tantalum electrolytic capacitors. The large surface compared to a smooth one is the second reason for the


title: "Electrolytic capacitor" content: relatively high capacitance values of electrolytic capacitors compared with other capacitor families. Because the forming voltage defines the oxide layer thickness, the desired voltage rating can be produced very simply. Electrolytic capacitors have high volumetric efficiency, the so-called "CV product", defined as the product of capacitance and voltage divide by volume. Combinations of anode materials for electrolytic capacitors and the electrolytes used have given rise to wide varieties of capacitor types with different properties. An outline of the main characteristics of the different types is shown in the table below. The non-solid or so-called "wet" aluminum electrolytic capacitors were and


title: "Electrolytic capacitor" content: are the cheapest among all other conventional capacitors. They not only provide the cheapest solutions for high capacitance or voltage values for decoupling and buffering purposes but are also insensitive to low ohmic charging and discharging as well as to low-energy transients. Non-solid electrolytic capacitors can be found in nearly all areas of electronic devices, with the exception of military applications. Tantalum electrolytic capacitors with solid electrolyte as surface-mountable chip capacitors are mainly used in electronic devices in which little space is available or a low profile is required. They operate reliably over a wide temperature range without large parameter


title: "Electrolytic capacitor" content: deviations. In military and space applications only tantalum electrolytic capacitors have the necessary approvals. Niobium electrolytic capacitors are in direct competition with industrial tantalum electrolytic capacitors because niobium is more readily available. Their properties are comparable. The electrical properties of aluminum, tantalum and niobium electrolytic capacitors have been greatly improved by the polymer electrolyte. In order to compare the different characteristics of the different electrolytic capacitor types, capacitors with the same dimensions and of similar capacitance and voltage are compared in the following table. In such a comparison the values for ESR and ripple current load are the most important


title: "Electrolytic capacitor" content: parameters for the use of electrolytic capacitors in modern electronic equipment. The lower the ESR, the higher the ripple current per volume and better functionality of the capacitor in the circuit. However, better electrical parameters come with higher prices. ) Manufacturer, series name, capacitance/voltage ) calculated for a capacitor 100 µF/10 V, ) from a 1976 data sheet Aluminum electrolytic capacitors form the bulk of the electrolytic capacitors used in electronics because of the large diversity of sizes and the inexpensive production. Tantalum electrolytic capacitors, usually used in the SMD version, have a higher specific capacitance than the aluminum electrolytic


title: "Electrolytic capacitor" content: capacitors and are used in devices with limited space or flat design such as laptops. They are also used in military technology, mostly in axial style, hermetically sealed. Niobium electrolytic chip capacitors are a new development in the market and are intended as a replacement for tantalum electrolytic chip capacitors. The phenomenon that in an electrochemical process, aluminum and such metals as tantalum, niobium, manganese, titanium, zinc, cadmium, etc., can form an oxide layer which blocks an electric current from flowing in one direction but which allows current to flow in the opposite direction, was first observed in 1857 by


title: "Electrolytic capacitor" content: the German physicist and chemist (1805–1878). It was first put to use in 1875 by the French researcher and founder Eugène Ducretet, who coined the term "valve metal" for such metals. Charles Pollak (born Karol Pollak), a producer of accumulators, found out that the oxide layer on an aluminum anode remained stable in a neutral or alkaline electrolyte, even when the power was switched off. In 1896 he filed a patent for an "Electric liquid capacitor with aluminum electrodes" (de: "Elektrischer Flüssigkeitskondensator mit Aluminiumelektroden") based on his idea of using the oxide layer in a polarized capacitor in combination with


title: "Electrolytic capacitor" content: a neutral or slightly alkaline electrolyte. The first industrially realized electrolytic capacitors consisted of a metallic box used as the cathode. It was filled with a borax electrolyte dissolved in water, in which a folded aluminum anode plate was inserted. Applying a DC voltage from outside, an oxide layer was formed on the surface of the anode. The advantage of these capacitors was that they were significantly smaller and cheaper than all other capacitors at this time relative to the realized capacitance value. This construction with different styles of anode construction but with a case as cathode and container for


title: "Electrolytic capacitor" content: the electrolyte was used up to the 1930s and was called a "wet" electrolytic capacitor, in the sense of its having a high water content. The first more common application of wet aluminum electrolytic capacitors was in large telephone exchanges, to reduce relay hash (noise) on the 48 volt DC power supply. The development of AC-operated domestic radio receivers in the late 1920s created a demand for large-capacitance (for the time) and high-voltage capacitors for the valve amplifier technique, typically at least 4 microfarads and rated at around 500 volts DC. Waxed paper and oiled silk film capacitors were available,


title: "Electrolytic capacitor" content: but devices with that order of capacitance and voltage rating were bulky and prohibitively expensive. The ancestor of the modern electrolytic capacitor was patented by Samuel Ruben in 1925, who teamed with Philip Mallory, the founder of the battery company that is now known as Duracell International. Ruben's idea adopted the stacked construction of a silver mica capacitor. He introduced a separated second foil to contact the electrolyte adjacent to the anode foil instead of using the electrolyte-filled container as the capacitor's cathode. The stacked second foil got its own terminal additional to the anode terminal and the container no


title: "Electrolytic capacitor" content: longer had an electrical function. This type of electrolytic capacitor combined with an liquid or gel-like electrolyte of a non-aqueous nature, which is therefore dry in the sense of having a very low water content, became known as the "dry" type of electrolytic capacitor. With Ruben's invention, together with the invention of wound foils separated with a paper spacer 1927 by A. Eckel of Hydra-Werke (Germany), the actual development of e-caps began. William Dubilier, whose first patent for electrolytic capacitors was filed in 1928, industrialized the new ideas for electrolytic capacitors and started the first large commercial production in 1931


title: "Electrolytic capacitor" content: in the Cornell-Dubilier (CD) factory in Plainfield, New Jersey. At the same time in Berlin, Germany, the "Hydra-Werke", an AEG company, started the production of e-caps in large quantities. In his 1896 patent Pollak already recognized that the capacitance of the capacitor increases when roughening the surface of the anode foil. Today (2014), electrochemically etched low voltage foils can achieve an up to 200-fold increase in surface area compared to a smooth surface. Advances in the etching process are the reason for the dimension reductions in aluminum electrolytic capacitors over recent decades. For aluminum electrolytic capacitors the decades from 1970


title: "Electrolytic capacitor" content: to 1990 were marked by the development of various new professional series specifically suited to certain industrial applications, for example with very low leakage currents or with long life characteristics, or for higher temperatures up to 125 °C. One of the first tantalum electrolytic capacitors were developed in 1930 by Tansitor Electronic Inc. USA, for military purposes. The basic construction of a wound cell was adopted and a tantalum anode foil was used together with a tantalum cathode foil, separated with a paper spacer impregnated with a liquid electrolyte, mostly sulfuric acid, and encapsulated in a silver case. The relevant


title: "Electrolytic capacitor" content: development of solid electrolyte tantalum capacitors began some years after William Shockley, John Bardeen and Walter Houser Brattain invented the transistor in 1947. It was invented by Bell Laboratories in the early 1950s as a miniaturized, more reliable low-voltage support capacitor to complement their newly invented transistor. The solution found by R. L. Taylor and H. E. Haring of the Bell labs in early 1950 was based on experiences with ceramics. They ground tantalum to a powder, which they pressed into a cylindrical form and then sintered at high a temperature between 1500 and 2000 °C under vacuum conditions to


title: "Electrolytic capacitor" content: produce a pellet ("slug"). These first sintered tantalum capacitors used a non-solid electrolyte, which does not fit the concept of solid electronics. In 1952 a targeted search at Bell Labs by D. A. McLean and F. S. Power for a solid electrolyte led to the invention of manganese dioxide as a solid electrolyte for a sintered tantalum capacitor. Although fundamental inventions came from Bell Labs, the inventions for manufacturing commercially viable tantalum electrolytic capacitors came from researchers at the Sprague Electric Company. Preston Robinson, Sprague's Director of Research, is considered to be the actual inventor of tantalum capacitors in 1954.


title: "Electrolytic capacitor" content: His invention was supported by R. J. Millard, who introduced the "reform" step in 1955, a significant improvement in which the dielectric of the capacitor was repaired after each dip-and-convert cycle of MnO deposition, which dramatically reduced the leakage current of the finished capacitors. Although solid tantalum capacitors offered capacitors with lower ESR and leakage current values than the aluminum e-caps, 1980 a price shock for tantalum dramatically reduced the applications of Ta-e-caps especially in the entertainment industry. The industry switched back to using aluminum electrolytic capacitors. The first solid electrolyte of manganese dioxide developed 1952 for tantalum capacitors had


title: "Electrolytic capacitor" content: a conductivity 10 times better than all other types of non-solid electrolytes. It also influenced the development of aluminum electrolytic capacitors. In 1964 the first aluminum electrolytic capacitors with solid electrolyte SAL electrolytic capacitor came on the market, developed by Philips. With the beginning of digitalization, Intel launched in 1971 its first microcomputer, MCS 4, and in 1972 Hewlett Packard launched one of the first pocket calculators, HP 35. The requirements for capacitors increased in terms of lowering the equivalent series resistance (ESR) for bypass and decoupling capacitors. The manganese dioxide type of electrolyte should be better. It was not


title: "Electrolytic capacitor" content: until 1983 when a new step toward ESR reduction was taken by Sanyo with its "OS-CON" aluminum electrolytic capacitors. These capacitors used a solid organic conductor, the charge transfer salt TTF-TCNQ (tetracyanoquinodimethane), which provided an improvement in conductivity by a factor of 10 compared with the manganese dioxide electrolyte. The next step in ESR reduction was the development of conducting polymers by Alan J. Heeger, Alan MacDiarmid and Hideki Shirakawa in 1975. The conductivity of conductive polymers such as polypyrrole (PPy) or PEDOT is better than that of TCNQ by a factor of 100 to 500, and close to the


title: "Electrolytic capacitor" content: conductivity of metals. In 1991 Panasonic came on the market with its "SP-Cap", called polymer aluminum electrolytic capacitors. These aluminum electrolytic capacitors with polymer electrolytes reached very low ESR values directly comparable to ceramic multilayer capacitors (MLCCs). They were still less expensive than tantalum capacitors and with their flat design for laptops and cell phones competed with tantalum chip capacitors as well. Tantalum electrolytic capacitors with PPy polymer electrolyte cathode followed three years later. In 1993 NEC introduced its SMD polymer tantalum electrolytic capacitors, called "NeoCap". In 1997 Sanyo followed with the "POSCAP" polymer tantalum chips. A new conductive polymer


title: "Electrolytic capacitor" content: for tantalum polymer capacitors was presented by Kemet at the "1999 Carts" conference. This capacitor used the newly developed organic conductive polymer PEDT Poly(3,4-ethylenedioxythiophene), also known as PEDOT (trade name Baytron®) Another price explosion for tantalum in 2000/2001 forced the development of niobium electrolytic capacitors with manganese dioxide electrolyte, which have been available since 2002. Niobium is a sister metal to tantalum and serves as valve metal generating an oxide layer during anodic oxidation. Niobium as raw material is much more abundant in nature than tantalum and is less expensive. It was a question of the availability of the base


title: "Electrolytic capacitor" content: metal in the late 1960s which led to development and implementation of niobium electrolytic capacitors in the former Soviet Union instead of tantalum capacitors as in the West. The materials and processes used to produce niobium-dielectric capacitors are essentially the same as for existing tantalum-dielectric capacitors. The characteristics of niobium electrolytic capacitors and tantalum electrolytic capacitors are roughly comparable. With the goal of reducing ESR for inexpensive non-solid e-caps from the mid-1980s in Japan, new water-based electrolytes for aluminum electrolytic capacitors were developed. Water is inexpensive, an effective solvent for electrolytes, and significantly improves the conductivity of the electrolyte. The


title: "Electrolytic capacitor" content: Japanese manufacturer Rubycon was a leader in the development of new water-based electrolyte systems with enhanced conductivity in the late 1990s. The new series of non-solid e-caps with water-based electrolyte was described in the data sheets as having "low-ESR", "low-impedance", "ultra-low-impedance" or "high-ripple current". A stolen recipe for such a water-based electrolyte, in which important stabilizing substances were absent, led in the years 2000 to 2005 to the problem of mass-bursting capacitors in computers and power supplies, which became known under the term "capacitor plague". In these e-caps the water reacts quite aggressively and even violently with aluminum, accompanied by


title: "Electrolytic capacitor" content: strong heat and gas development in the capacitor, and often led to the explosion of the capacitor. The electrical characteristics of capacitors are harmonized by the international generic specification IEC 60384-1. In this standard, the electrical characteristics of capacitors are described by an idealized series-equivalent circuit with electrical components which model all ohmic losses, capacitive and inductive parameters of an electrolytic capacitor: The electrical characteristics of electrolytic capacitors depend on the structure of the anode and the electrolyte used. This influences the capacitance value of electrolytic capacitors, which depends on measuring frequency and temperature. Electrolytic capacitors with non-solid electrolytes show


title: "Electrolytic capacitor" content: a broader aberration over frequency and temperature ranges than do capacitors with solid electrolytes. The basic unit of an electrolytic capacitor's capacitance is the microfarad (μF). The capacitance value specified in the data sheets of the manufacturers is called the rated capacitance C or nominal capacitance C and is the value for which the capacitor has been designed. The standardized measuring condition for e-caps is an AC measuring method with 0.5 V at a frequency of 100/120 Hz and a temperature of 20 °C. For tantalum capacitors a DC bias voltage of 1.1 to 1.5 V for types with a


title: "Electrolytic capacitor" content: rated voltage ≤2.5 V, or 2.1 to 2.5 V for types with a rated voltage of >2.5 V, may be applied during the measurement to avoid reverse voltage. The capacitance value measured at the frequency of 1 kHz is about 10% less than the 100/120 Hz value. Therefore, the capacitance values of electrolytic capacitors are not directly comparable and differ from those of film capacitors or ceramic capacitors, whose capacitance is measured at 1 kHz or higher. Measured with an AC measuring method with 100/120 Hz the capacitance value is the closest value to the electrical charge stored in the


title: "Electrolytic capacitor" content: e-caps. The stored charge is measured with a special discharge method and is called the DC capacitance. The DC capacitance is about 10% higher than the 100/120 Hz AC capacitance. The DC capacitance is of interest for discharge applications like photoflash. The percentage of allowed deviation of the measured capacitance from the rated value is called the capacitance tolerance. Electrolytic capacitors are available in different tolerance series, whose values are specified in the E series specified in IEC 60063. For abbreviated marking in tight spaces, a letter code for each tolerance is specified in IEC 60062. The required capacitance tolerance


title: "Electrolytic capacitor" content: is determined by the particular application. Electrolytic capacitors, which are often used for filtering and bypassing, do not have the need for narrow tolerances because they are mostly not used for accurate frequency applications like in oscillators. Referring to the IEC/EN 60384-1 standard, the allowed operating voltage for electrolytic capacitors is called the "rated voltage U" or "nominal voltage U". The rated voltage U is the maximum DC voltage or peak pulse voltage that may be applied continuously at any temperature within the rated temperature range T. The voltage proof of electrolytic capacitors decreases with increasing temperature. For some applications


title: "Electrolytic capacitor" content: it is important to use a higher temperature range. Lowering the voltage applied at a higher temperature maintains safety margins. For some capacitor types therefore the IEC standard specifies a "temperature derated voltage" for a higher temperature, the "category voltage U". The category voltage is the maximum DC voltage or peak pulse voltage that may be applied continuously to a capacitor at any temperature within the category temperature range T. The relation between both voltages and temperatures is given in the picture at right. Applying a higher voltage than specified may destroy electrolytic capacitors. Applying a lower voltage may have


title: "Electrolytic capacitor" content: a positive influence on electrolytic capacitors. For aluminum electrolytic capacitors a lower applied voltage can in some cases extend the lifetime. For tantalum electrolytic capacitors lowering the voltage applied increases the reliability and reduces the expected failure rate. I The surge voltage indicates the maximum peak voltage value that may be applied to electrolytic capacitors during their application for a limited number of cycles. The surge voltage is standardized in IEC/EN 60384-1. For aluminum electrolytic capacitors with a rated voltage of up to 315 V, the surge voltage is 1.15 times the rated voltage, and for capacitors with a rated


title: "Electrolytic capacitor" content: voltage exceeding 315 V, the surge voltage is 1.10 times the rated voltage. For tantalum electrolytic capacitors the surge voltage can be 1.3 times the rated voltage, rounded off to the nearest volt. The surge voltage applied to tantalum capacitors may influence the capacitor's failure rate. Aluminum electrolytic capacitors with non-solid electrolyte are relatively insensitive to high and short-term transient voltages higher than surge voltage, if the frequency and the energy content of the transients are low. This ability depends on rated voltage and component size. Low energy transient voltages lead to a voltage limitation similar to a zener diode.


title: "Electrolytic capacitor" content: An unambiguous and general specification of tolerable transients or peak voltages is not possible. In every case transients arise, the application has to be approved very carefully. Electrolytic capacitors with solid manganese oxide or polymer electrolyte, and aluminum as well as tantalum electrolytic capacitors can not withstand transients or peak voltages higher than surge voltage. Transients for this type of e-caps may destroy the components. Standard electrolytic capacitors, and aluminum as well as tantalum and niobium electrolytic capacitors are polarized and generally require the anode electrode voltage to be positive relative to the cathode voltage. Nevertheless, electrolytic capacitors can withstand


title: "Electrolytic capacitor" content: for short instants a reverse voltage for a limited number of cycles. In detail, aluminum electrolytic capacitors with non-solid electrolyte can withstand a reverse voltage of about 1 V to 1.5 V. This reverse voltage should never be used to determine the maximum reverse voltage under which a capacitor can be used permanently. Solid tantalum capacitors can also withstand reverse voltages for short periods. The most common guidelines for tantalum reverse voltage are: These guidelines apply for short excursion and should never be used to determine the maximum reverse voltage under which a capacitor can be used permanently. But in


title: "Electrolytic capacitor" content: no case, for aluminum as well as for tantalum and niobium electrolytic capacitors, may a reverse voltage be used for a permanent AC application. To minimize the likelihood of a polarized electrolytic being incorrectly inserted into a circuit, polarity has to be very clearly indicated on the case, see the section on "Polarity marking" below. Special bipolar aluminum electrolytic capacitors designed for bipolar operation are available, and usually referred to as "non-polarized" or "bipolar" types. In these, the capacitors have two anode foils with full-thickness oxide layers connected in reverse polarity. On the alternate halves of the AC cycles, one


title: "Electrolytic capacitor" content: of the oxides on the foil acts as a blocking dielectric, preventing reverse current from damaging the electrolyte of the other one. But these bipolar electrolytic capacitors are not adaptable for main AC applications instead of power capacitors with metallized polymer film or paper dielectric. In general, a capacitor is seen as a storage component for electric energy. But this is only one capacitor function. A capacitor can also act as an AC resistor. Especially aluminum electrolytic capacitors in many applications are used as decoupling capacitors to filter or bypass undesired biased AC frequencies to the ground or for capacitive


title: "Electrolytic capacitor" content: coupling of audio AC signals. Then the dielectric is used only for blocking DC. For such applications the AC resistance, the impedance, is as important as the capacitance value. The impedance "Z" is the vector sum of reactance and resistance; it describes the phase difference and the ratio of amplitudes between sinusoidally varying voltage and sinusoidally varying current at a given frequency. In this sense impedance is a measure of the ability of the capacitor to pass alternating currents and can be used like Ohm's law. In other words, the impedance is a frequency-dependent AC resistance and possesses both magnitude


title: "Electrolytic capacitor" content: and phase at a particular frequency. In data sheets of electrolytic capacitors only the impedance magnitude "|Z|" is specified, and simply written as ""Z"." Regarding the IEC/EN 60384-1 standard, the impedance values of electrolytic capacitors are measured and specified at 10 kHz or 100 kHz depending on the capacitance and voltage of the capacitor. Besides measuring, the impedance can be calculated using the idealized components of a capacitor's series-equivalent circuit, including an ideal capacitor "C", a resistor "ESR", and an inductance "ESL". In this case the impedance at the angular frequency "ω" is given by the geometric (complex) addition of


title: "Electrolytic capacitor" content: "ESR", by a capacitive reactance "X" and by an inductive reactance "X" (Inductance) formula_4. Then "Z" is given by Electrolytic capacitor An electrolytic capacitor (abbreviated e-cap) is a polarized capacitor whose anode or positive plate is made of a metal that forms an insulating oxide layer through anodization. This oxide layer acts as the dielectric of the capacitor. A solid, liquid, or gel electrolyte covers the surface of this oxide layer, serving as the (cathode) or negative plate of the capacitor. Due to their very thin dielectric oxide layer and enlarged anode surface, electrolytic capacitors have a much higher capacitance-voltage


title: "Lapland longspur" content: Lapland longspur The Lapland longspur ("Calcarius lapponicus"), also known as the Lapland bunting, is a passerine bird in the longspur family Calcariidae, a group separated by most modern authors from the Fringillidae (Old World finches). The English name refers to the long hind claws. The genus name "Calcarius" is from Latin "calcaria", "spurs", and the specific "lapponicus" refers to Lapland. The Lapland longspur is a robust bird, with a thick yellow seed-eater's bill. The summer male has a black head and throat, white eyestripe, chestnut nape, white underparts, and a heavily streaked black-grey back. Other plumages have a plainer orange-brown


title: "Lapland longspur" content: head, a browner back and chestnut nape and wing panels. It breeds across Arctic Europe and Asia and in Canada and the northernmost United States. It is migratory, wintering in the Russian steppes, the southern United States, Northern Scandinavian arctic areas and down to coastal Southern Sweden, Denmark and Great Britain. This is the only Eurasian species of the longspur buntings, and while it probably did not evolve there, it has been present in Eastern Europe for at least about 30,000 years. The most common flight call is a hard "prrrrt" usually preceded by a more nasal "teeww". When breeding,


title: "Lapland longspur" content: it also makes a softer "duyyeee" followed by a pause and a "triiiuuu"; both sounds alternate. It breeds in wet areas with birch or willow, and or bare mountains, and winters on cultivated land or coasts. The bird is often seen close to the tree line, and likes to feed in mixed-species flocks in winter. Its natural food consists of insects when feeding young, and otherwise seeds. The nest is on the ground. 2–4 eggs are laid. The food habits of the Lapland longspur are quite simple: mostly seeds in winter and arthropods in the summer, when they are in


title: "Lapland longspur" content: activity. During the winter, the longspur feeds on seeds. They pick them on the ground, rarely feeding directly on plants. They will forage around the same area for a period varying between a few minutes and an hour, then fly away looking for a new foraging area. Their seed diet is composed mainly of seeds from grass, foxtail, cultivated millet, crabgrass and wheat. During the breeding season, the birds migrate to the north, where their diet switches to arthropods. Nestlings are only fed arthropods, which also constitute the diet of the parents at that time of the year (June to


title: "Lapland longspur" content: July). The birds often catch insects in mid-air, but do forage through vegetation when climatic conditions prevent the insects from flying. Longspurs can consume between 3000 and 10,000 prey items (insects or seeds) per day, depending on their energy needs. Dipteran larvae and adults form the major part of their insectivorous diet. Lapland longspur The Lapland longspur ("Calcarius lapponicus"), also known as the Lapland bunting, is a passerine bird in the longspur family Calcariidae, a group separated by most modern authors from the Fringillidae (Old World finches). The English name refers to the long hind claws. The genus name "Calcarius"


title: "Lawn mower" content: Lawn mower A lawn mower (also named as mower or lawnmower) is a machine utilizing one or more revolving blades to cut a grass surface to an even height. The height of the cut grass may be fixed by the design of the mower, but generally is adjustable by the operator, typically by a single master lever, or by a lever or nut and bolt on each of the machine's wheels. The blades may be powered by muscle, with wheels mechanically connected to the cutting blades so that when the mower is pushed forward, the blades spin, or the machine


title: "Lawn mower" content: may have a battery-powered or plug-in electric motor. The most common power source for lawn mowers is a small (typically one cylinder) internal combustion engine. Smaller mowers often lack any form of propulsion, requiring human power to move over a surface; "walk-behind" mowers are self-propelled, requiring a human only to walk behind and guide them. Larger lawn mowers are usually either self-propelled "walk-behind" types, or more often, are "ride-on" mowers, equipped so the operator can ride on the mower and control it. A robotic lawn mower ("lawn-mowing bot", "mowbot", etc.) is designed to operate either entirely on its own, or


title: "Lawn mower" content: less commonly by an operator by remote control. Two main styles of blades are used in lawn mowers. Lawn mowers employing a single blade that rotates about a single vertical axis are known as rotary mowers, while those employing a cutting bar and multiple blade assembly that rotates about a single horizontal axis are known as cylinder or reel mowers (although in some versions, the cutting bar is the only blade, and the rotating assembly consists of flat metal pieces which force the blades of grass against the sharp cutting bar). There are several types of mowers, each suited to


title: "Lawn mower" content: a particular scale and purpose. The smallest types, non-powered push mowers, are suitable for small residential lawns and gardens. Electrical or piston engine-powered push-mowers are used for larger residential lawns (although there is some overlap). Riding mowers, which sometimes resemble small tractors, are larger than push mowers and are suitable for large lawns, although commercial riding lawn mowers (such as zero-turn mowers) can be "stand-on" types, and often bear little resemblance to residential lawn tractors, being designed to mow large areas at high speed in the shortest time possible. The largest multi-gang (multi-blade) mowers are mounted on tractors and are