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Solar thermal power stations include the 354 megawatt (MW) Solar Energy Generating Systems power plant in the USA, Solnova Solar Power Station (Spain, 150 MW), Andasol solar power station (Spain, 100 MW), Nevada Solar One (USA, 64 MW), PS20 solar power tower (Spain, 20 MW), and the PS10 solar power tower (Spain, 11 MW). The 370 MW Ivanpah Solar Power Facility, located in California's Mojave Desert, is the world's largest solar-thermal power plant project currently under construction. Many other plants are under construction or planned, mainly in Spain and the USA. In developing countries, three World Bank projects for integrated solar thermal/combined-cycle gas-turbine power plants in Egypt, Mexico, and Morocco have been approved.
Nearly all the gasoline sold in the United States today is mixed with 10 percent ethanol, a mix known as E10, and motor vehicle manufacturers already produce vehicles designed to run on much higher ethanol blends. Ford, DaimlerChrysler, and GM are among the automobile companies that sell flexible-fuel cars, trucks, and minivans that can use gasoline and ethanol blends ranging from pure gasoline up to 85% ethanol (E85). The challenge is to expand the market for biofuels beyond the farm states where they have been most popular to date. The Energy Policy Act of 2005, which calls for 7.5 billion US gallons (28,000,000 m3) of biofuels to be used annually by 2012, will also help to expand the market.
According to the International Energy Agency, cellulosic ethanol biorefineries could allow biofuels to play a much bigger role in the future than organizations such as the IEA previously thought. Cellulosic ethanol can be made from plant matter composed primarily of inedible cellulose fibers that form the stems and branches of most plants. Crop residues (such as corn stalks, wheat straw and rice straw), wood waste, and municipal solid waste are potential sources of cellulosic biomass. Dedicated energy crops, such as switchgrass, are also promising cellulose sources that can be sustainably produced in many regions.
As of 2008[update], geothermal power development was under way in more than 40 countries, partially attributable to the development of new technologies, such as Enhanced Geothermal Systems. The development of binary cycle power plants and improvements in drilling and extraction technology may enable enhanced geothermal systems over a much greater geographical range than "traditional" Geothermal systems. Demonstration EGS projects are operational in the USA, Australia, Germany, France, and The United Kingdom.
The PV industry has seen drops in module prices since 2008. In late 2011, factory-gate prices for crystalline-silicon photovoltaic modules dropped below the $1.00/W mark. The $1.00/W installed cost, is often regarded in the PV industry as marking the achievement of grid parity for PV. These reductions have taken many stakeholders, including industry analysts, by surprise, and perceptions of current solar power economics often lags behind reality. Some stakeholders still have the perspective that solar PV remains too costly on an unsubsidized basis to compete with conventional generation options. Yet technological advancements, manufacturing process improvements, and industry re-structuring, mean that further price reductions are likely in coming years.
Many energy markets, institutions, and policies have been developed to support the production and use of fossil fuels. Newer and cleaner technologies may offer social and environmental benefits, but utility operators often reject renewable resources because they are trained to think only in terms of big, conventional power plants. Consumers often ignore renewable power systems because they are not given accurate price signals about electricity consumption. Intentional market distortions (such as subsidies), and unintentional market distortions (such as split incentives) may work against renewables. Benjamin K. Sovacool has argued that "some of the most surreptitious, yet powerful, impediments facing renewable energy and energy efficiency in the United States are more about culture and institutions than engineering and science".
Lester Brown states that the market "does not incorporate the indirect costs of providing goods or services into prices, it does not value nature's services adequately, and it does not respect the sustainable-yield thresholds of natural systems". It also favors the near term over the long term, thereby showing limited concern for future generations. Tax and subsidy shifting can help overcome these problems, though is also problematic to combine different international normative regimes regulating this issue.
Tax shifting has been widely discussed and endorsed by economists. It involves lowering income taxes while raising levies on environmentally destructive activities, in order to create a more responsive market. For example, a tax on coal that included the increased health care costs associated with breathing polluted air, the costs of acid rain damage, and the costs of climate disruption would encourage investment in renewable technologies. Several Western European countries are already shifting taxes in a process known there as environmental tax reform.
Just as there is a need for tax shifting, there is also a need for subsidy shifting. Subsidies are not an inherently bad thing as many technologies and industries emerged through government subsidy schemes. The Stern Review explains that of 20 key innovations from the past 30 years, only one of the 14 was funded entirely by the private sector and nine were totally publicly funded. In terms of specific examples, the Internet was the result of publicly funded links among computers in government laboratories and research institutes. And the combination of the federal tax deduction and a robust state tax deduction in California helped to create the modern wind power industry.
Renewable energy commercialization involves the deployment of three generations of renewable energy technologies dating back more than 100 years. First-generation technologies, which are already mature and economically competitive, include biomass, hydroelectricity, geothermal power and heat. Second-generation technologies are market-ready and are being deployed at the present time; they include solar heating, photovoltaics, wind power, solar thermal power stations, and modern forms of bioenergy. Third-generation technologies require continued R&D efforts in order to make large contributions on a global scale and include advanced biomass gasification, hot-dry-rock geothermal power, and ocean energy. As of 2012, renewable energy accounts for about half of new nameplate electrical capacity installed and costs are continuing to fall.
Lester Brown has argued that "a world facing the prospect of economically disruptive climate change can no longer justify subsidies to expand the burning of coal and oil. Shifting these subsidies to the development of climate-benign energy sources such as wind, solar, biomass, and geothermal power is the key to stabilizing the earth's climate." The International Solar Energy Society advocates "leveling the playing field" by redressing the continuing inequities in public subsidies of energy technologies and R&D, in which the fossil fuel and nuclear power receive the largest share of financial support.
Some countries are eliminating or reducing climate disrupting subsidies and Belgium, France, and Japan have phased out all subsidies for coal. Germany is reducing its coal subsidy. The subsidy dropped from $5.4 billion in 1989 to $2.8 billion in 2002, and in the process Germany lowered its coal use by 46 percent. China cut its coal subsidy from $750 million in 1993 to $240 million in 1995 and more recently has imposed a high-sulfur coal tax. However, the United States has been increasing its support for the fossil fuel and nuclear industries.
Setting national renewable energy targets can be an important part of a renewable energy policy and these targets are usually defined as a percentage of the primary energy and/or electricity generation mix. For example, the European Union has prescribed an indicative renewable energy target of 12 per cent of the total EU energy mix and 22 per cent of electricity consumption by 2010. National targets for individual EU Member States have also been set to meet the overall target. Other developed countries with defined national or regional targets include Australia, Canada, Israel, Japan, Korea, New Zealand, Norway, Singapore, Switzerland, and some US States.
Public policy determines the extent to which renewable energy (RE) is to be incorporated into a developed or developing country's generation mix. Energy sector regulators implement that policy—thus affecting the pace and pattern of RE investments and connections to the grid. Energy regulators often have authority to carry out a number of functions that have implications for the financial feasibility of renewable energy projects. Such functions include issuing licenses, setting performance standards, monitoring the performance of regulated firms, determining the price level and structure of tariffs, establishing uniform systems of accounts, arbitrating stakeholder disputes (like interconnection cost allocations), performing management audits, developing agency human resources (expertise), reporting sector and commission activities to government authorities, and coordinating decisions with other government agencies. Thus, regulators make a wide range of decisions that affect the financial outcomes associated with RE investments. In addition, the sector regulator is in a position to give advice to the government regarding the full implications of focusing on climate change or energy security. The energy sector regulator is the natural advocate for efficiency and cost-containment throughout the process of designing and implementing RE policies. Since policies are not self-implementing, energy sector regulators become a key facilitator (or blocker) of renewable energy investments.
The driving force behind voluntary green electricity within the EU are the liberalized electricity markets and the RES Directive. According to the directive the EU Member States must ensure that the origin of electricity produced from renewables can be guaranteed and therefore a "guarantee of origin" must be issued (article 15). Environmental organisations are using the voluntary market to create new renewables and improving sustainability of the existing power production. In the US the main tool to track and stimulate voluntary actions is Green-e program managed by Center for Resource Solutions. In Europe the main voluntary tool used by the NGOs to promote sustainable electricity production is EKOenergy label.
A number of events in 2006 pushed renewable energy up the political agenda, including the US mid-term elections in November, which confirmed clean energy as a mainstream issue. Also in 2006, the Stern Review made a strong economic case for investing in low carbon technologies now, and argued that economic growth need not be incompatible with cutting energy consumption. According to a trend analysis from the United Nations Environment Programme, climate change concerns coupled with recent high oil prices and increasing government support are driving increasing rates of investment in the renewable energy and energy efficiency industries.
New government spending, regulation, and policies helped the industry weather the 2009 economic crisis better than many other sectors. Most notably, U.S. President Barack Obama's American Recovery and Reinvestment Act of 2009 included more than $70 billion in direct spending and tax credits for clean energy and associated transportation programs. This policy-stimulus combination represents the largest federal commitment in U.S. history for renewables, advanced transportation, and energy conservation initiatives. Based on these new rules, many more utilities strengthened their clean-energy programs. Clean Edge suggests that the commercialization of clean energy will help countries around the world deal with the current economic malaise. Once-promising solar energy company, Solyndra, became involved in a political controversy involving U.S. President Barack Obama's administration's authorization of a $535 million loan guarantee to the Corporation in 2009 as part of a program to promote alternative energy growth. The company ceased all business activity, filed for Chapter 11 bankruptcy, and laid-off nearly all of its employees in early September 2011.
As of 2012, renewable energy plays a major role in the energy mix of many countries globally. Renewables are becoming increasingly economic in both developing and developed countries. Prices for renewable energy technologies, primarily wind power and solar power, continued to drop, making renewables competitive with conventional energy sources. Without a level playing field, however, high market penetration of renewables is still dependent on a robust promotional policies. Fossil fuel subsidies, which are far higher than those for renewable energy, remain in place and quickly need to be phased out.
United Nations' Secretary-General Ban Ki-moon has said that "renewable energy has the ability to lift the poorest nations to new levels of prosperity". In October 2011, he "announced the creation of a high-level group to drum up support for energy access, energy efficiency and greater use of renewable energy. The group is to be co-chaired by Kandeh Yumkella, the chair of UN Energy and director general of the UN Industrial Development Organisation, and Charles Holliday, chairman of Bank of America".
Worldwide use of solar power and wind power continued to grow significantly in 2012. Solar electricity consumption increased by 58 percent, to 93 terawatt-hours (TWh). Use of wind power in 2012 increased by 18.1 percent, to 521.3 TWh. Global solar and wind energy installed capacities continued to expand even though new investments in these technologies declined during 2012. Worldwide investment in solar power in 2012 was $140.4 billion, an 11 percent decline from 2011, and wind power investment was down 10.1 percent, to $80.3 billion. But due to lower production costs for both technologies, total installed capacities grew sharply. This investment decline, but growth in installed capacity, may again occur in 2013. Analysts expect the market to triple by 2030. In 2015, investment in renewables exceeded fossils.
The incentive to use 100% renewable energy, for electricity, transport, or even total primary energy supply globally, has been motivated by global warming and other ecological as well as economic concerns. The Intergovernmental Panel on Climate Change has said that there are few fundamental technological limits to integrating a portfolio of renewable energy technologies to meet most of total global energy demand. In reviewing 164 recent scenarios of future renewable energy growth, the report noted that the majority expected renewable sources to supply more than 17% of total energy by 2030, and 27% by 2050; the highest forecast projected 43% supplied by renewables by 2030 and 77% by 2050. Renewable energy use has grown much faster than even advocates anticipated. At the national level, at least 30 nations around the world already have renewable energy contributing more than 20% of energy supply. Also, Professors S. Pacala and Robert H. Socolow have developed a series of "stabilization wedges" that can allow us to maintain our quality of life while avoiding catastrophic climate change, and "renewable energy sources," in aggregate, constitute the largest number of their "wedges."
Mark Z. Jacobson, professor of civil and environmental engineering at Stanford University and director of its Atmosphere and Energy Program says producing all new energy with wind power, solar power, and hydropower by 2030 is feasible and existing energy supply arrangements could be replaced by 2050. Barriers to implementing the renewable energy plan are seen to be "primarily social and political, not technological or economic". Jacobson says that energy costs with a wind, solar, water system should be similar to today's energy costs.
Similarly, in the United States, the independent National Research Council has noted that "sufficient domestic renewable resources exist to allow renewable electricity to play a significant role in future electricity generation and thus help confront issues related to climate change, energy security, and the escalation of energy costs … Renewable energy is an attractive option because renewable resources available in the United States, taken collectively, can supply significantly greater amounts of electricity than the total current or projected domestic demand." .
Palermo (Italian: [paˈlɛrmo] ( listen), Sicilian: Palermu, Latin: Panormus, from Greek: Πάνορμος, Panormos, Arabic: بَلَرْم‎, Balarm; Phoenician: זִיז, Ziz) is a city in Insular Italy, the capital of both the autonomous region of Sicily and the Province of Palermo. The city is noted for its history, culture, architecture and gastronomy, playing an important role throughout much of its existence; it is over 2,700 years old. Palermo is located in the northwest of the island of Sicily, right by the Gulf of Palermo in the Tyrrhenian Sea.
The city was founded in 734 BC by the Phoenicians as Ziz ('flower'). Palermo then became a possession of Carthage, before becoming part of the Roman Republic, the Roman Empire and eventually part of the Byzantine Empire, for over a thousand years. The Greeks named the city Panormus meaning 'complete port'. From 831 to 1072 the city was under Arab rule during the Emirate of Sicily when the city first became a capital. The Arabs shifted the Greek name into Balarm, the root for Palermo's present-day name. Following the Norman reconquest, Palermo became the capital of a new kingdom (from 1130 to 1816), the Kingdom of Sicily and the capital of the Holy Roman Empire under Frederick II Holy Roman Emperor and Conrad IV of Germany, King of the Romans. Eventually Sicily would be united with the Kingdom of Naples to form the Kingdom of the Two Sicilies until the Italian unification of 1860.
Palermo is Sicily's cultural, economic and touristic capital. It is a city rich in history, culture, art, music and food. Numerous tourists are attracted to the city for its good Mediterranean weather, its renowned gastronomy and restaurants, its Romanesque, Gothic and Baroque churches, palaces and buildings, and its nightlife and music. Palermo is the main Sicilian industrial and commercial center: the main industrial sectors include tourism, services, commerce and agriculture. Palermo currently has an international airport, and a significant underground economy.[citation needed] In fact, for cultural, artistic and economic reasons, Palermo was one of the largest cities in the Mediterranean and is now among the top tourist destinations in both Italy and Europe. The city is also going through careful redevelopment, preparing to become one of the major cities of the Euro-Mediterranean area.
Palermo is surrounded by mountains, formed of calcar, which form a cirque around the city. Some districts of the city are divided by the mountains themselves. Historically, it was relatively difficult to reach the inner part of Sicily from the city because of the mounts. The tallest peak of the range is La Pizzuta, about 1,333 m (4,373 ft.) high. However, historically, the most important mount is Monte Pellegrino, which is geographically separated from the rest of the range by a plain. The mount lies right in front of the Tyrrhenian Sea. Monte Pellegrino's cliff was described in the 19th century by Johann Wolfgang von Goethe, as "The most beautiful promontory in the world", in his essay "Italian Journey".
Today both the Papireto river and the Kemonia are covered up by buildings. However, the shape of the former watercourses can still be recognised today, because the streets that were built on them follow their shapes. Today the only waterway not drained yet is the Oreto river that divides the downtown of the city from the western uptown and the industrial districts. In the basins there were, though, many seasonal torrents that helped formed swampy plains, reclaimed during history; a good example of which can be found in the borough of Mondello.
During 734 BC the Phoenicians, a sea trading people from the north of ancient Canaan, built a small settlement on the natural harbor of Palermo. Some sources suggest they named the settlement "Ziz." It became one of the three main Phoenician colonies of Sicily, along with Motya and Soluntum. However, the remains of the Phoenician presence in the city are few and mostly preserved in the very populated center of the downtown area, making any excavation efforts costly and logistically difficult. The site chosen by the Phoenicians made it easy to connect the port to the mountains with a straight road that today has become Corso Calatifimi. This road helped the Phoenicians in trading with the populations that lived beyond the mountains that surround the gulf.
The first settlement is defined as Paleapolis (Παλεάπολις), the Ancient Greek world for "old city", in order to distinguish it from a second settlement built during the 5th century BC, called Neapolis (Νεάπολις), "new city". The neapolis was erected towards the east and along with it, monumental walls around the whole settlement were built to prevent attacks from foreign threats. Some part of this structure can still be seen in the Cassaro district. This district was named after the walls themselves; the word Cassaro deriving from the Arab al-qsr (castle, stronghold). Along the walls there were few doors to access and exit the city, suggesting that trade even toward the inner part of the island occurred frequently. Moreover, according to some studies, it may be possible that there were some walls that divided the old city from the new one too. The colony developed around a central street (decumanus), cut perpendicularly by minor streets. This street today has become the Corso Vittorio Emanuele.
Carthage was Palermo’s major trading partner under the Phoenicians and the city enjoyed a prolonged peace during this period. Palermo came into contact with the Ancient Greeks between the 6th and the 5th centuries BC which preceded the Sicilian Wars, a conflict fought between the Greeks of Syracuse and the Phoenicians of Carthage for control over the island of Sicily. During this war the Greeks named the settlement Panormos (Πάνορμος) from which the current name is derived, meaning "all port" due to the shape of its coast. It was from Palermo that Hamilcar I's fleet (which was defeated at the Battle of Himera) was launched. In 409 B.C. the city was looted by Hermocrates of Syracuse. The Sicilian Wars ended in 265 BC when Carthage and Syracuse stopped warring and united in order to stop the Romans from gaining full control of the island during the First Punic War. In 276 BC, during the Pyrrhic War, Panormos briefly became a Greek colony after being conquered by Pyrrhus of Epirus, but returned to Phoenician Carthage in 275. In 254 BC Panormos was besieged and conquered by the Romans in the first battle of Panormus (the name Latin name). Carthage attempted to reconquer Panormus in 251 BC but failed.
As the Roman Empire was falling apart, Palermo fell under the control of several Germanic tribes. The first were the Vandals in 440 AD under the rule of their king Geiseric. The Vandals had occupied all the Roman provinces in North Africa by 455 establishing themselves as a significant force. They acquired Corsica, Sardinia and Sicily shortly afterwards. However, they soon lost these newly acquired possessions to the Ostrogoths. The Ostrogothic conquest under Theodoric the Great began in 488; Theodoric supported Roman culture and government unlike the Germanic Goths. The Gothic War took place between the Ostrogoths and the Eastern Roman Empire, also known as the Byzantine Empire. Sicily was the first part of Italy to be taken under control of General Belisarius who was commissioned by Eastern Emperor. Justinian I solidified his rule in the following years.
The Muslims took control of the Island in 904, after decades of fierce fighting, and the Emirate of Sicily was established. Muslim rule on the island lasted for about 120 years and was marked by cruelty and brutality against the native population, which was reduced into near slavery[clarification needed] and Christian churches across the island were all completely destroyed.[page needed] Palermo (Balarm during Arab rule) displaced Syracuse as the capital city of Sicily. It was said to have then begun to compete with Córdoba and Cairo in terms of importance and splendor. For more than one hundred years Palermo was the capital of a flourishing emirate. The Arabs also introduced many agricultural crops which remain a mainstay of Sicilian cuisine.
After dynastic quarrels however, there was a Christian reconquest in 1072. The family who returned the city to Christianity were called the Hautevilles, including Robert Guiscard and his army, who is regarded as a hero by the natives. It was under Roger II of Sicily that Norman holdings in Sicily and the southern part of the Italian Peninsula were promoted from the County of Sicily into the Kingdom of Sicily. The Kingdom's capital was Palermo, with the King's Court held at the Palazzo dei Normanni. Much construction was undertaken during this period, such as the building of Palermo Cathedral. The Kingdom of Sicily became one of the wealthiest states in Europe.
Sicily fell under the control of the Holy Roman Empire in 1194. Palermo was the preferred city of the Emperor Frederick II. Muslims of Palermo emigrated or were expelled during Holy Roman rule. After an interval of Angevin rule (1266–1282), Sicily came under control of the Aragon and Barcelona dynasties. By 1330, Palermo's population had declined to 51,000. From 1479 until 1713 Palermo was ruled by the Kingdom of Spain, and again between 1717 and 1718. Palermo was also under Savoy control between 1713 and 1717 and 1718–1720 as a result of the Treaty of Utrecht. It was also ruled by Austria between 1720 and 1734.
After the Treaty of Utrecht (1713), Sicily was handed over to the Savoia, but by 1734 it was again a Bourbon possession. Charles III chose Palermo for his coronation as King of Sicily. Charles had new houses built for the growing population, while trade and industry grew as well. However, by now Palermo was now just another provincial city as the Royal Court resided in Naples. Charles' son Ferdinand, though disliked by the population, took refuge in Palermo after the French Revolution in 1798. His son Alberto died on the way to Palermo and is buried in the city. When the Kingdom of the Two Sicilies was founded, the original capital city was Palermo (1816) but a year later moved to Naples.
From 1820 to 1848 Sicily was shaken by upheavals, which culminated on 12 January 1848, with a popular insurrection, the first one in Europe that year, led by Giuseppe La Masa. A parliament and constitution were proclaimed. The first president was Ruggero Settimo. The Bourbons reconquered Palermo in 1849, and remained under their rule until the time of Giuseppe Garibaldi. The famous general entered Palermo with his troops (the “Thousands”) on 27 May 1860. After the plebiscite later that year Palermo, along with the rest of Sicily, became part of the new Kingdom of Italy (1861).
The majority of Sicilians preferred independence to the Savoia kingdom; in 1866, Palermo became the seat of a week-long popular rebellion, which was finally crushed after Martial law was declared. The Italian government blamed anarchists and the Church, specifically the Archbishop of Palermo, for the rebellion and began enacting anti-Sicilian and anti-clerical policies. A new cultural, economic and industrial growth was spurred by several families, like the Florio, the Ducrot, the Rutelli, the Sandron, the Whitaker, the Utveggio, and others. In the early twentieth century Palermo expanded outside the old city walls, mostly to the north along the new boulevards Via Roma, Via Dante, Via Notarbartolo, and Viale della Libertà. These roads would soon boast a huge number of villas in the Art Nouveau style. Many of these were designed by the famous architect Ernesto Basile. The Grand Hotel Villa Igiea, designed by Ernesto Basile for the Florio family, is a good example of Palermitan Art Nouveau. The huge Teatro Massimo was designed in the same period by Giovan Battista Filippo Basile, and built by the Rutelli & Machì building firm of the industrial and old Rutelli Italian family in Palermo, and was opened in 1897.
The so-called "Sack of Palermo" is one of the major visible faces of the problem. The term is used to indicate the speculative building practices that have filled the city with poor buildings. The reduced importance of agriculture in the Sicilian economy has led to a massive migration to the cities, especially Palermo, which swelled in size, leading to rapid expansion towards the north. The regulatory plans for expansion was largely ignored in the boom. New parts of town appeared almost out of nowhere, but without parks, schools, public buildings, proper roads and the other amenities that characterise a modern city.
Palermo experiences a hot-summer Mediterranean climate (Köppen climate classification: Csa). Winters are cool and wet, while summers are hot and dry. Temperatures in autumn and spring are usually mild. Palermo is one of the warmest cities in Europe (mainly due to its warm nights), with an average annual air temperature of 18.5 °C (65.3 °F). It receives approximately 2,530 hours of sunshine per year. Snow is usually a rare occurrence, but it does occur occasionally if there is a cold front, as the Apennines are too distant to protect the island from cold winds blowing from the Balkans, and the mountains surrounding the city facilite the formation of snow accumulation in Palermo, especially at night. Between the 1940s and the 2000s there have been eleven times when considerable snowfall has occurred: In 1949, in 1956, when the minimum temperature went down to 0 °C (32 °F) and the city was blanketed by several centimeters of snow. Snow also occurred in 1999, 2009 and 2015. The average annual temperature of the sea is above 19 °C (66 °F); from 14 °C (57 °F) in February to 26 °C (79 °F) in August. In the period from May to November, the average sea temperature exceeds 18 °C (64 °F) and in the period from June to October, the average sea temperature exceeds 21 °C (70 °F).
Palermo has at least 2 circuits of City Walls - many pieces of which still survive. The first circuit surrounded the ancient core of the punic City - the so-called Palaeopolis (in the area east of Porta Nuova) and the Neopolis. Via Vittorio Emanuele was the main road east-west through this early walled city. The eastern edge of the walled city was on Via Roma and the ancient port in the vicinity of Piazza Marina. The wall circuit was approximately Porto Nuovo, Corso Alberti, Piazza Peranni, Via Isodoro, Via Candela, Via Venezia, Via Roma, Piazza Paninni, Via Biscottari, Via Del Bastione, Palazzo dei Normanni and back to Porto Nuovo.
In the medieval period the wall circuit was expanded. Via Vittorio Emanuele continued to be the main road east-west through the walled city. West gate was still Porta Nuova, the circuit continued to Corso Alberti, to Piazza Vittorio Emanuele Orlando where it turned east along Via Volturno to Piazza Verdi and along the line of Via Cavour. At this north-east corner there was a defence, Castello a Mare, to protect the port at La Cala. A huge chain was used to block La Cala with the other end at S Maria della Catena (St Mary of the Chain). The sea-side wall was along the western side of Foro Italico Umberto. The wall turns west along the northern side of Via Abramo Lincoln, continues along Corso Tukory. The wall turns north approximately on Via Benedetto, to Palazzo dei Normanni and back to Porta Nuova. Source: Palermo - City Guide by Adriana Chirco, 1998, Dario Flaccovio Editore.
The cathedral has a heliometer (solar "observatory") of 1690, one of a number built in Italy in the 17th and 18th centuries. The device itself is quite simple: a tiny hole in one of the minor domes acts as pinhole camera, projecting an image of the sun onto the floor at solar noon (12:00 in winter, 13:00 in summer). There is a bronze line, la Meridiana on the floor, running precisely N/S. The ends of the line mark the positions as at the summer and winter solstices; signs of the zodiac show the various other dates throughout the year.
In 2010, there were 1.2 million people living in the greater Palermo area, 655,875 of which resided in the City boundaries, of whom 47.4% were male and 52.6% were female. People under age 15 totalled 15.6% compared to pensioners who composed 17.2% of the population. This compares with the Italian average of 14.1% people under 15 years and 20.2% pensioners. The average age of a Palermo resident is 40.4 compared to the Italian average of 42.8. In the ten years between 2001 and 2010, the population of Palermo declined by 4.5%, while the population of Italy, as a whole, grew by 6.0%. The reason for Palermo's decline is a population flight to the suburbs, and to Northern Italy. The current birth rate of Palermo is 10.2 births per 1,000 inhabitants compared to the Italian average of 9.3 births.
Being Sicily's administrative capital, Palermo is a centre for much of the region's finance, tourism and commerce. The city currently hosts an international airport, and Palermo's economic growth over the years has brought the opening of many new businesses. The economy mainly relies on tourism and services, but also has commerce, shipbuilding and agriculture. The city, however, still has high unemployment levels, high corruption and a significant black market empire (Palermo being the home of the Sicilian Mafia). Even though the city still suffers from widespread corruption, inefficient bureaucracy and organized crime, the level of crime in Palermo's has gone down dramatically, unemployment has been decreasing and many new, profitable opportunities for growth (especially regarding tourism) have been introduced, making the city safer and better to live in.
The port of Palermo, founded by the Phoenicians over 2,700 years ago, is, together with the port of Messina, the main port of Sicily. From here ferries link Palermo to Cagliari, Genoa, Livorno, Naples, Tunis and other cities and carry a total of almost 2 million passengers annually. It is also an important port for cruise ships. Traffic includes also almost 5 million tonnes of cargo and 80.000 TEU yearly. The port also has links to minor sicilian islands such as Ustica and the Aeolian Islands (via Cefalù in summer). Inside the Port of Palermo there is a section known as "tourist marina" for sailing yachts and catamarans.
The patron saint of Palermo is Santa Rosalia, who is widely revered. On 14 July, people in Palermo celebrate the annual Festino, the most important religious event of the year. The Festino is a procession which goes through the main street of Palermo to commemorate the miracle attributed to Santa Rosalia who, it is believed, freed the city from the Black Death in 1624. Her remains were discovered in a cave on Monte Pellegrino, and her remains were carried around the city three times, banishing the plague. There is a sanctuary marking the spot where her remains were found which can be reached via a scenic bus ride from the city.
Zinc is a chemical element with symbol Zn and atomic number 30. It is the first element of group 12 of the periodic table. In some respects zinc is chemically similar to magnesium: its ion is of similar size and its only common oxidation state is +2. Zinc is the 24th most abundant element in Earth's crust and has five stable isotopes. The most common zinc ore is sphalerite (zinc blende), a zinc sulfide mineral. The largest mineable amounts are found in Australia, Asia, and the United States. Zinc production includes froth flotation of the ore, roasting, and final extraction using electricity (electrowinning).
Brass, which is an alloy of copper and zinc, has been used since at least the 10th century BC in Judea and by the 7th century BC in Ancient Greece. Zinc metal was not produced on a large scale until the 12th century in India and was unknown to Europe until the end of the 16th century. The mines of Rajasthan have given definite evidence of zinc production going back to the 6th century BC. To date, the oldest evidence of pure zinc comes from Zawar, in Rajasthan, as early as the 9th century AD when a distillation process was employed to make pure zinc. Alchemists burned zinc in air to form what they called "philosopher's wool" or "white snow".
The element was probably named by the alchemist Paracelsus after the German word Zinke (prong, tooth). German chemist Andreas Sigismund Marggraf is credited with discovering pure metallic zinc in 1746. Work by Luigi Galvani and Alessandro Volta uncovered the electrochemical properties of zinc by 1800. Corrosion-resistant zinc plating of iron (hot-dip galvanizing) is the major application for zinc. Other applications are in batteries, small non-structural castings, and alloys, such as brass. A variety of zinc compounds are commonly used, such as zinc carbonate and zinc gluconate (as dietary supplements), zinc chloride (in deodorants), zinc pyrithione (anti-dandruff shampoos), zinc sulfide (in luminescent paints), and zinc methyl or zinc diethyl in the organic laboratory.
Zinc is an essential mineral perceived by the public today as being of "exceptional biologic and public health importance", especially regarding prenatal and postnatal development. Zinc deficiency affects about two billion people in the developing world and is associated with many diseases. In children it causes growth retardation, delayed sexual maturation, infection susceptibility, and diarrhea. Enzymes with a zinc atom in the reactive center are widespread in biochemistry, such as alcohol dehydrogenase in humans. Consumption of excess zinc can cause ataxia, lethargy and copper deficiency.
Zinc is a bluish-white, lustrous, diamagnetic metal, though most common commercial grades of the metal have a dull finish. It is somewhat less dense than iron and has a hexagonal crystal structure, with a distorted form of hexagonal close packing, in which each atom has six nearest neighbors (at 265.9 pm) in its own plane and six others at a greater distance of 290.6 pm. The metal is hard and brittle at most temperatures but becomes malleable between 100 and 150 °C. Above 210 °C, the metal becomes brittle again and can be pulverized by beating. Zinc is a fair conductor of electricity. For a metal, zinc has relatively low melting (419.5 °C) and boiling points (907 °C). Its melting point is the lowest of all the transition metals aside from mercury and cadmium.
Several dozen radioisotopes have been characterized. 65Zn, which has a half-life of 243.66 days, is the most long-lived radioisotope, followed by 72Zn with a half-life of 46.5 hours. Zinc has 10 nuclear isomers. 69mZn has the longest half-life, 13.76 h. The superscript m indicates a metastable isotope. The nucleus of a metastable isotope is in an excited state and will return to the ground state by emitting a photon in the form of a gamma ray. 61Zn has three excited states and 73Zn has two. The isotopes 65Zn, 71Zn, 77Zn and 78Zn each have only one excited state.
The chemistry of zinc is dominated by the +2 oxidation state. When compounds in this oxidation state are formed the outer shell s electrons are lost, which yields a bare zinc ion with the electronic configuration [Ar]3d10. In aqueous solution an octahedral complex, [Zn(H 2O)6]2+ is the predominant species. The volatilization of zinc in combination with zinc chloride at temperatures above 285 °C indicates the formation of Zn 2Cl 2, a zinc compound with a +1 oxidation state. No compounds of zinc in oxidation states other than +1 or +2 are known. Calculations indicate that a zinc compound with the oxidation state of +4 is unlikely to exist.
Zinc chemistry is similar to the chemistry of the late first-row transition metals nickel and copper, though it has a filled d-shell, so its compounds are diamagnetic and mostly colorless. The ionic radii of zinc and magnesium happen to be nearly identical. Because of this some of their salts have the same crystal structure and in circumstances where ionic radius is a determining factor zinc and magnesium chemistries have much in common. Otherwise there is little similarity. Zinc tends to form bonds with a greater degree of covalency and it forms much more stable complexes with N- and S- donors. Complexes of zinc are mostly 4- or 6- coordinate although 5-coordinate complexes are known.
Zinc(I) compounds are rare, and require bulky ligands to stabilize the low oxidation state. Most zinc(I) compounds contain formally the [Zn2]2+ core, which is analogous to the [Hg2]2+ dimeric cation present in mercury(I) compounds. The diamagnetic nature of the ion confirms its dimeric structure. The first zinc(I) compound containing the Zn—Zn bond, (η5-C5Me5)2Zn2, is also the first dimetallocene. The [Zn2]2+ ion rapidly disproportionates into zinc metal and zinc(II), and has only been obtained as a yellow glass formed by cooling a solution of metallic zinc in molten ZnCl2.
Binary compounds of zinc are known for most of the metalloids and all the nonmetals except the noble gases. The oxide ZnO is a white powder that is nearly insoluble in neutral aqueous solutions, but is amphoteric, dissolving in both strong basic and acidic solutions. The other chalcogenides (ZnS, ZnSe, and ZnTe) have varied applications in electronics and optics. Pnictogenides (Zn 3N 2, Zn 3P 2, Zn 3As 2 and Zn 3Sb 2), the peroxide (ZnO 2), the hydride (ZnH 2), and the carbide (ZnC 2) are also known. Of the four halides, ZnF 2 has the most ionic character, whereas the others (ZnCl 2, ZnBr 2, and ZnI 2) have relatively low melting points and are considered to have more covalent character.
In weak basic solutions containing Zn2+ ions, the hydroxide Zn(OH) 2 forms as a white precipitate. In stronger alkaline solutions, this hydroxide is dissolved to form zincates ([Zn(OH)4]2−). The nitrate Zn(NO3) 2, chlorate Zn(ClO3) 2, sulfate ZnSO 4, phosphate Zn 3(PO4) 2, molybdate ZnMoO 4, cyanide Zn(CN) 2, arsenite Zn(AsO2) 2, arsenate Zn(AsO4) 2·8H 2O and the chromate ZnCrO 4 (one of the few colored zinc compounds) are a few examples of other common inorganic compounds of zinc. One of the simplest examples of an organic compound of zinc is the acetate (Zn(O 2CCH3) 2).
The Charaka Samhita, thought to have been written between 300 and 500 AD, mentions a metal which, when oxidized, produces pushpanjan, thought to be zinc oxide. Zinc mines at Zawar, near Udaipur in India, have been active since the Mauryan period. The smelting of metallic zinc here, however, appears to have begun around the 12th century AD. One estimate is that this location produced an estimated million tonnes of metallic zinc and zinc oxide from the 12th to 16th centuries. Another estimate gives a total production of 60,000 tonnes of metallic zinc over this period. The Rasaratna Samuccaya, written in approximately the 13th century AD, mentions two types of zinc-containing ores: one used for metal extraction and another used for medicinal purposes.
The name of the metal was probably first documented by Paracelsus, a Swiss-born German alchemist, who referred to the metal as "zincum" or "zinken" in his book Liber Mineralium II, in the 16th century. The word is probably derived from the German zinke, and supposedly meant "tooth-like, pointed or jagged" (metallic zinc crystals have a needle-like appearance). Zink could also imply "tin-like" because of its relation to German zinn meaning tin. Yet another possibility is that the word is derived from the Persian word سنگ seng meaning stone. The metal was also called Indian tin, tutanego, calamine, and spinter.
William Champion's brother, John, patented a process in 1758 for calcining zinc sulfide into an oxide usable in the retort process. Prior to this, only calamine could be used to produce zinc. In 1798, Johann Christian Ruberg improved on the smelting process by building the first horizontal retort smelter. Jean-Jacques Daniel Dony built a different kind of horizontal zinc smelter in Belgium, which processed even more zinc. Italian doctor Luigi Galvani discovered in 1780 that connecting the spinal cord of a freshly dissected frog to an iron rail attached by a brass hook caused the frog's leg to twitch. He incorrectly thought he had discovered an ability of nerves and muscles to create electricity and called the effect "animal electricity". The galvanic cell and the process of galvanization were both named for Luigi Galvani and these discoveries paved the way for electrical batteries, galvanization and cathodic protection.
Zinc metal is produced using extractive metallurgy. After grinding the ore, froth flotation, which selectively separates minerals from gangue by taking advantage of differences in their hydrophobicity, is used to get an ore concentrate. This concentrate consists of about 50% zinc with the rest being sulfur (32%), iron (13%), and SiO 2 (5%). The composition of this is normally zinc sulfide (80% to 85%), iron sulfide (7.0% to 12%), lead sulfide (3.0% to 5.0%) silica (2.5% to 3.5%), and cadmium sulfide (0.35% to 0.41%).
The production for sulfidic zinc ores produces large amounts of sulfur dioxide and cadmium vapor. Smelter slag and other residues of process also contain significant amounts of heavy metals. About 1.1 million tonnes of metallic zinc and 130 thousand tonnes of lead were mined and smelted in the Belgian towns of La Calamine and Plombières between 1806 and 1882. The dumps of the past mining operations leach significant amounts of zinc and cadmium, and, as a result, the sediments of the Geul River contain significant amounts of heavy metals. About two thousand years ago emissions of zinc from mining and smelting totaled 10 thousand tonnes a year. After increasing 10-fold from 1850, zinc emissions peaked at 3.4 million tonnes per year in the 1980s and declined to 2.7 million tonnes in the 1990s, although a 2005 study of the Arctic troposphere found that the concentrations there did not reflect the decline. Anthropogenic and natural emissions occur at a ratio of 20 to 1.
Zinc is more reactive than iron or steel and thus will attract almost all local oxidation until it completely corrodes away. A protective surface layer of oxide and carbonate (Zn 5(OH) 6(CO 3) 2) forms as the zinc corrodes. This protection lasts even after the zinc layer is scratched but degrades through time as the zinc corrodes away. The zinc is applied electrochemically or as molten zinc by hot-dip galvanizing or spraying. Galvanization is used on chain-link fencing, guard rails, suspension bridges, lightposts, metal roofs, heat exchangers, and car bodies.
The relative reactivity of zinc and its ability to attract oxidation to itself makes it an efficient sacrificial anode in cathodic protection (CP). For example, cathodic protection of a buried pipeline can be achieved by connecting anodes made from zinc to the pipe. Zinc acts as the anode (negative terminus) by slowly corroding away as it passes electric current to the steel pipeline.[note 2] Zinc is also used to cathodically protect metals that are exposed to sea water from corrosion. A zinc disc attached to a ship's iron rudder will slowly corrode, whereas the rudder stays unattacked. Other similar uses include a plug of zinc attached to a propeller or the metal protective guard for the keel of the ship.
Other widely used alloys that contain zinc include nickel silver, typewriter metal, soft and aluminium solder, and commercial bronze. Zinc is also used in contemporary pipe organs as a substitute for the traditional lead/tin alloy in pipes. Alloys of 85–88% zinc, 4–10% copper, and 2–8% aluminium find limited use in certain types of machine bearings. Zinc is the primary metal used in making American one cent coins since 1982. The zinc core is coated with a thin layer of copper to give the impression of a copper coin. In 1994, 33,200 tonnes (36,600 short tons) of zinc were used to produce 13.6 billion pennies in the United States.
Alloys of primarily zinc with small amounts of copper, aluminium, and magnesium are useful in die casting as well as spin casting, especially in the automotive, electrical, and hardware industries. These alloys are marketed under the name Zamak. An example of this is zinc aluminium. The low melting point together with the low viscosity of the alloy makes the production of small and intricate shapes possible. The low working temperature leads to rapid cooling of the cast products and therefore fast assembly is possible. Another alloy, marketed under the brand name Prestal, contains 78% zinc and 22% aluminium and is reported to be nearly as strong as steel but as malleable as plastic. This superplasticity of the alloy allows it to be molded using die casts made of ceramics and cement.
Similar alloys with the addition of a small amount of lead can be cold-rolled into sheets. An alloy of 96% zinc and 4% aluminium is used to make stamping dies for low production run applications for which ferrous metal dies would be too expensive. In building facades, roofs or other applications in which zinc is used as sheet metal and for methods such as deep drawing, roll forming or bending, zinc alloys with titanium and copper are used. Unalloyed zinc is too brittle for these kinds of manufacturing processes.
Roughly one quarter of all zinc output in the United States (2009), is consumed in the form of zinc compounds; a variety of which are used industrially. Zinc oxide is widely used as a white pigment in paints, and as a catalyst in the manufacture of rubber. It is also used as a heat disperser for the rubber and acts to protect its polymers from ultraviolet radiation (the same UV protection is conferred to plastics containing zinc oxide). The semiconductor properties of zinc oxide make it useful in varistors and photocopying products. The zinc zinc-oxide cycle is a two step thermochemical process based on zinc and zinc oxide for hydrogen production.
Zinc chloride is often added to lumber as a fire retardant and can be used as a wood preservative. It is also used to make other chemicals. Zinc methyl (Zn(CH3) 2) is used in a number of organic syntheses. Zinc sulfide (ZnS) is used in luminescent pigments such as on the hands of clocks, X-ray and television screens, and luminous paints. Crystals of ZnS are used in lasers that operate in the mid-infrared part of the spectrum. Zinc sulfate is a chemical in dyes and pigments. Zinc pyrithione is used in antifouling paints.
64Zn, the most abundant isotope of zinc, is very susceptible to neutron activation, being transmuted into the highly radioactive 65Zn, which has a half-life of 244 days and produces intense gamma radiation. Because of this, Zinc Oxide used in nuclear reactors as an anti-corrosion agent is depleted of 64Zn before use, this is called depleted zinc oxide. For the same reason, zinc has been proposed as a salting material for nuclear weapons (cobalt is another, better-known salting material). A jacket of isotopically enriched 64Zn would be irradiated by the intense high-energy neutron flux from an exploding thermonuclear weapon, forming a large amount of 65Zn significantly increasing the radioactivity of the weapon's fallout. Such a weapon is not known to have ever been built, tested, or used. 65Zn is also used as a tracer to study how alloys that contain zinc wear out, or the path and the role of zinc in organisms.
Zinc is included in most single tablet over-the-counter daily vitamin and mineral supplements. Preparations include zinc oxide, zinc acetate, and zinc gluconate. It is believed to possess antioxidant properties, which may protect against accelerated aging of the skin and muscles of the body; studies differ as to its effectiveness. Zinc also helps speed up the healing process after an injury. It is also suspected of being beneficial to the body's immune system. Indeed, zinc deficiency may have effects on virtually all parts of the human immune system.
Although not yet tested as a therapy in humans, a growing body of evidence indicates that zinc may preferentially kill prostate cancer cells. Because zinc naturally homes to the prostate and because the prostate is accessible with relatively non-invasive procedures, its potential as a chemotherapeutic agent in this type of cancer has shown promise. However, other studies have demonstrated that chronic use of zinc supplements in excess of the recommended dosage may actually increase the chance of developing prostate cancer, also likely due to the natural buildup of this heavy metal in the prostate.
There are many important organozinc compounds. Organozinc chemistry is the science of organozinc compounds describing their physical properties, synthesis and reactions. Among important applications is the Frankland-Duppa Reaction in which an oxalate ester(ROCOCOOR) reacts with an alkyl halide R'X, zinc and hydrochloric acid to the α-hydroxycarboxylic esters RR'COHCOOR, the Reformatskii reaction which converts α-halo-esters and aldehydes to β-hydroxy-esters, the Simmons–Smith reaction in which the carbenoid (iodomethyl)zinc iodide reacts with alkene(or alkyne) and converts them to cyclopropane, the Addition reaction of organozinc compounds to carbonyl compounds. The Barbier reaction (1899) is the zinc equivalent of the magnesium Grignard reaction and is better of the two. In presence of just about any water the formation of the organomagnesium halide will fail, whereas the Barbier reaction can even take place in water. On the downside organozincs are much less nucleophilic than Grignards, are expensive and difficult to handle. Commercially available diorganozinc compounds are dimethylzinc, diethylzinc and diphenylzinc. In one study the active organozinc compound is obtained from much cheaper organobromine precursors:
Zinc serves a purely structural role in zinc fingers, twists and clusters. Zinc fingers form parts of some transcription factors, which are proteins that recognize DNA base sequences during the replication and transcription of DNA. Each of the nine or ten Zn2+ ions in a zinc finger helps maintain the finger's structure by coordinately binding to four amino acids in the transcription factor. The transcription factor wraps around the DNA helix and uses its fingers to accurately bind to the DNA sequence.
Other sources include fortified food and dietary supplements, which come in various forms. A 1998 review concluded that zinc oxide, one of the most common supplements in the United States, and zinc carbonate are nearly insoluble and poorly absorbed in the body. This review cited studies which found low plasma zinc concentrations after zinc oxide and zinc carbonate were consumed compared with those seen after consumption of zinc acetate and sulfate salts. However, harmful excessive supplementation is a problem among the relatively affluent, and should probably not exceed 20 mg/day in healthy people, although the U.S. National Research Council set a Tolerable Upper Intake of 40 mg/day.
For fortification, however, a 2003 review recommended zinc oxide in cereals as cheap, stable, and as easily absorbed as more expensive forms. A 2005 study found that various compounds of zinc, including oxide and sulfate, did not show statistically significant differences in absorption when added as fortificants to maize tortillas. A 1987 study found that zinc picolinate was better absorbed than zinc gluconate or zinc citrate. However, a study published in 2008 determined that zinc glycinate is the best absorbed of the four dietary supplement types available.
Symptoms of mild zinc deficiency are diverse. Clinical outcomes include depressed growth, diarrhea, impotence and delayed sexual maturation, alopecia, eye and skin lesions, impaired appetite, altered cognition, impaired host defense properties, defects in carbohydrate utilization, and reproductive teratogenesis. Mild zinc deficiency depresses immunity, although excessive zinc does also. Animals with a diet deficient in zinc require twice as much food in order to attain the same weight gain as animals given sufficient zinc.
Despite some concerns, western vegetarians and vegans have not been found to suffer from overt zinc deficiencies any more than meat-eaters. Major plant sources of zinc include cooked dried beans, sea vegetables, fortified cereals, soyfoods, nuts, peas, and seeds. However, phytates in many whole-grains and fiber in many foods may interfere with zinc absorption and marginal zinc intake has poorly understood effects. The zinc chelator phytate, found in seeds and cereal bran, can contribute to zinc malabsorption. There is some evidence to suggest that more than the US RDA (15 mg) of zinc daily may be needed in those whose diet is high in phytates, such as some vegetarians. These considerations must be balanced against the fact that there is a paucity of adequate zinc biomarkers, and the most widely used indicator, plasma zinc, has poor sensitivity and specificity. Diagnosing zinc deficiency is a persistent challenge.
Nearly two billion people in the developing world are deficient in zinc. In children it causes an increase in infection and diarrhea, contributing to the death of about 800,000 children worldwide per year. The World Health Organization advocates zinc supplementation for severe malnutrition and diarrhea. Zinc supplements help prevent disease and reduce mortality, especially among children with low birth weight or stunted growth. However, zinc supplements should not be administered alone, because many in the developing world have several deficiencies, and zinc interacts with other micronutrients.
Zinc deficiency is crop plants' most common micronutrient deficiency; it is particularly common in high-pH soils. Zinc-deficient soil is cultivated in the cropland of about half of Turkey and India, a third of China, and most of Western Australia, and substantial responses to zinc fertilization have been reported in these areas. Plants that grow in soils that are zinc-deficient are more susceptible to disease. Zinc is primarily added to the soil through the weathering of rocks, but humans have added zinc through fossil fuel combustion, mine waste, phosphate fertilizers, pesticide (zinc phosphide), limestone, manure, sewage sludge, and particles from galvanized surfaces. Excess zinc is toxic to plants, although zinc toxicity is far less widespread.
There is evidence of induced copper deficiency in those taking 100–300 mg of zinc daily. A 2007 trial observed that elderly men taking 80 mg daily were hospitalized for urinary complications more often than those taking a placebo. The USDA RDA is 11 and 8 mg Zn/day for men and women, respectively. Levels of 100–300 mg may interfere with the utilization of copper and iron or adversely affect cholesterol. Levels of zinc in excess of 500 ppm in soil interfere with the ability of plants to absorb other essential metals, such as iron and manganese. There is also a condition called the zinc shakes or "zinc chills" that can be induced by the inhalation of freshly formed zinc oxide formed during the welding of galvanized materials. Zinc is a common ingredient of denture cream which may contain between 17 and 38 mg of zinc per gram. There have been claims of disability, and even death, due to excessive use of these products.
The U.S. Food and Drug Administration (FDA) has stated that zinc damages nerve receptors in the nose, which can cause anosmia. Reports of anosmia were also observed in the 1930s when zinc preparations were used in a failed attempt to prevent polio infections. On June 16, 2009, the FDA said that consumers should stop using zinc-based intranasal cold products and ordered their removal from store shelves. The FDA said the loss of smell can be life-threatening because people with impaired smell cannot detect leaking gas or smoke and cannot tell if food has spoiled before they eat it. Recent research suggests that the topical antimicrobial zinc pyrithione is a potent heat shock response inducer that may impair genomic integrity with induction of PARP-dependent energy crisis in cultured human keratinocytes and melanocytes.
In 1982, the US Mint began minting pennies coated in copper but made primarily of zinc. With the new zinc pennies, there is the potential for zinc toxicosis, which can be fatal. One reported case of chronic ingestion of 425 pennies (over 1 kg of zinc) resulted in death due to gastrointestinal bacterial and fungal sepsis, whereas another patient, who ingested 12 grams of zinc, only showed lethargy and ataxia (gross lack of coordination of muscle movements). Several other cases have been reported of humans suffering zinc intoxication by the ingestion of zinc coins.
Pennies and other small coins are sometimes ingested by dogs, resulting in the need for medical treatment to remove the foreign body. The zinc content of some coins can cause zinc toxicity, which is commonly fatal in dogs, where it causes a severe hemolytic anemia, and also liver or kidney damage; vomiting and diarrhea are possible symptoms. Zinc is highly toxic in parrots and poisoning can often be fatal. The consumption of fruit juices stored in galvanized cans has resulted in mass parrot poisonings with zinc.
Many early 19th-century neoclassical architects were influenced by the drawings and projects of Étienne-Louis Boullée and Claude Nicolas Ledoux. The many graphite drawings of Boullée and his students depict spare geometrical architecture that emulates the eternality of the universe. There are links between Boullée's ideas and Edmund Burke's conception of the sublime. Ledoux addressed the concept of architectural character, maintaining that a building should immediately communicate its function to the viewer: taken literally such ideas give rise to "architecture parlante".
The baroque style had never truly been to the English taste. Four influential books were published in the first quarter of the 18th century which highlighted the simplicity and purity of classical architecture: Vitruvius Britannicus (Colen Campbell 1715), Palladio's Four Books of Architecture (1715), De Re Aedificatoria (1726) and The Designs of Inigo Jones... with Some Additional Designs (1727). The most popular was the four-volume Vitruvius Britannicus by Colen Campbell. The book contained architectural prints of famous British buildings that had been inspired by the great architects from Vitruvius to Palladio. At first the book mainly featured the work of Inigo Jones, but the later tomes contained drawings and plans by Campbell and other 18th-century architects. Palladian architecture became well established in 18th-century Britain.
At the forefront of the new school of design was the aristocratic "architect earl", Richard Boyle, 3rd Earl of Burlington; in 1729, he and William Kent, designed Chiswick House. This House was a reinterpretation of Palladio's Villa Capra, but purified of 16th century elements and ornament. This severe lack of ornamentation was to be a feature of the Palladianism. In 1734 William Kent and Lord Burlington designed one of England's finest examples of Palladian architecture with Holkham Hall in Norfolk. The main block of this house followed Palladio's dictates quite closely, but Palladio's low, often detached, wings of farm buildings were elevated in significance.
By the mid 18th century, the movement broadened to incorporate a greater range of Classical influences, including those from Ancient Greece. The shift to neoclassical architecture is conventionally dated to the 1750s. It first gained influence in England and France; in England, Sir William Hamilton's excavations at Pompeii and other sites, the influence of the Grand Tour and the work of William Chambers and Robert Adam, was pivotal in this regard. In France, the movement was propelled by a generation of French art students trained in Rome, and was influenced by the writings of Johann Joachim Winckelmann. The style was also adopted by progressive circles in other countries such as Sweden and Russia.
A second neoclassic wave, more severe, more studied and more consciously archaeological, is associated with the height of the Napoleonic Empire. In France, the first phase of neoclassicism was expressed in the "Louis XVI style", and the second in the styles called "Directoire" or Empire. The Rococo style remained popular in Italy until the Napoleonic regimes brought the new archaeological classicism, which was embraced as a political statement by young, progressive, urban Italians with republican leanings.[according to whom?]
Indoors, neoclassicism made a discovery of the genuine classic interior, inspired by the rediscoveries at Pompeii and Herculaneum. These had begun in the late 1740s, but only achieved a wide audience in the 1760s, with the first luxurious volumes of tightly controlled distribution of Le Antichità di Ercolano (The Antiquities of Herculaneum). The antiquities of Herculaneum showed that even the most classicising interiors of the Baroque, or the most "Roman" rooms of William Kent were based on basilica and temple exterior architecture turned outside in, hence their often bombastic appearance to modern eyes: pedimented window frames turned into gilded mirrors, fireplaces topped with temple fronts.
The new interiors sought to recreate an authentically Roman and genuinely interior vocabulary. Techniques employed in the style included flatter, lighter motifs, sculpted in low frieze-like relief or painted in monotones en camaïeu ("like cameos"), isolated medallions or vases or busts or bucrania or other motifs, suspended on swags of laurel or ribbon, with slender arabesques against backgrounds, perhaps, of "Pompeiian red" or pale tints, or stone colours. The style in France was initially a Parisian style, the Goût grec ("Greek style"), not a court style; when Louis XVI acceded to the throne in 1774, Marie Antoinette, his fashion-loving Queen, brought the "Louis XVI" style to court.
A new phase in neoclassical design was inaugurated by Robert and James Adam, who travelled in Italy and Dalmatia in the 1750s, observing the ruins of the classical world. On their return to Britain, they published a book entitled The Works in Architecture in installments between 1773 and 1779. This book of engraved designs made the Adam repertory available throughout Europe. The Adam brothers aimed to simplify the rococo and baroque styles which had been fashionable in the preceding decades, to bring what they felt to be a lighter and more elegant feel to Georgian houses. The Works in Architecture illustrated the main buildings the Adam brothers had worked on and crucially documented the interiors, furniture and fittings, designed by the Adams.
From about 1800 a fresh influx of Greek architectural examples, seen through the medium of etchings and engravings, gave a new impetus to neoclassicism, the Greek Revival. There was little to no direct knowledge of Greek civilization before the middle of the 18th century in Western Europe, when an expedition funded by the Society of Dilettanti in 1751 and led by James Stuart and Nicholas Revett began serious archaeological enquiry. Stuart was commissioned after his return from Greece by George Lyttelton to produce the first Greek building in England, the garden temple at Hagley Hall (1758–59). A number of British architects in the second half of the century took up the expressive challenge of the Doric from their aristocratic patrons, including Joseph Bonomi and John Soane, but it was to remain the private enthusiasm of connoisseurs up to the first decade of the 19th century.
Seen in its wider social context, Greek Revival architecture sounded a new note of sobriety and restraint in public buildings in Britain around 1800 as an assertion of nationalism attendant on the Act of Union, the Napoleonic Wars, and the clamour for political reform. It was to be William Wilkins's winning design for the public competition for Downing College, Cambridge that announced the Greek style was to be the dominant idiom in architecture. Wilkins and Robert Smirke went on to build some of the most important buildings of the era, including the Theatre Royal, Covent Garden (1808–09), the General Post Office (1824–29) and the British Museum (1823–48), Wilkins University College London (1826–30) and the National Gallery (1832–38). In Scotland, Thomas Hamilton (1784–1858), in collaboration with the artists Andrew Wilson (1780–1848) and Hugh William Williams (1773–1829) created monuments and buildings of international significance; the Burns Monument at Alloway (1818) and the (Royal) High School in Edinburgh (1823–29).
At the same time the Empire style in France was a more grandiose wave of neoclassicism in architecture and the decorative arts. Mainly based on Imperial Roman styles, it originated in, and took its name from, the rule of Napoleon I in the First French Empire, where it was intended to idealize Napoleon's leadership and the French state. The style corresponds to the more bourgeois Biedermeier style in the German-speaking lands, Federal style in the United States, the Regency style in Britain, and the Napoleonstil in Sweden. According to the art historian Hugh Honour "so far from being, as is sometimes supposed, the culmination of the Neo-classical movement, the Empire marks its rapid decline and transformation back once more into a mere antique revival, drained of all the high-minded ideas and force of conviction that had inspired its masterpieces".
High neoclassicism was an international movement. Though neoclassical architecture employed the same classical vocabulary as Late Baroque architecture, it tended to emphasize its planar qualities, rather than sculptural volumes. Projections and recessions and their effects of light and shade were more flat; sculptural bas-reliefs were flatter and tended to be enframed in friezes, tablets or panels. Its clearly articulated individual features were isolated rather than interpenetrating, autonomous and complete in themselves.
Neoclassicism also influenced city planning; the ancient Romans had used a consolidated scheme for city planning for both defence and civil convenience, however, the roots of this scheme go back to even older civilizations. At its most basic, the grid system of streets, a central forum with city services, two main slightly wider boulevards, and the occasional diagonal street were characteristic of the very logical and orderly Roman design. Ancient façades and building layouts were oriented to these city design patterns and they tended to work in proportion with the importance of public buildings.
From the middle of the 18th century, exploration and publication changed the course of British architecture towards a purer vision of the Ancient Greco-Roman ideal. James 'Athenian' Stuart's work The Antiquities of Athens and Other Monuments of Greece was very influential in this regard, as were Robert Wood's Palmyra and Baalbec. A combination of simple forms and high levels of enrichment was adopted by the majority of contemporary British architects and designers. The revolution begun by Stuart was soon to be eclipsed by the work of the Adam Brothers, James Wyatt, Sir William Chambers, George Dance, James Gandon and provincially based architects such as John Carr and Thomas Harrison of Chester.
In the early 20th century, the writings of Albert Richardson were responsible for a re-awakening of interest in pure neoclassical design. Vincent Harris (compare Harris's colonnaded and domed interior of Manchester Central Reference Library to the colonnaded and domed interior by John Carr and R R Duke), Bradshaw Gass & Hope and Percy Thomas were among those who designed public buildings in the neoclassical style in the interwar period. In the British Raj in India, Sir Edwin Lutyens' monumental city planning for New Delhi marked the sunset of neoclassicism. In Scotland and the north of England, where the Gothic Revival was less strong, architects continued to develop the neoclassical style of William Henry Playfair. The works of Cuthbert Brodrick and Alexander Thomson show that by the end of the 19th century the results could be powerful and eccentric.

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