Lead oxide makes it easier to dissolve what?


There are three classes of components for oxide glasses: network formers, intermediates, and modifiers. The network formers (silicon, boron, germanium) form a highly cross-linked network of chemical bonds. The intermediates (titanium, aluminium, zirconium, beryllium, magnesium, zinc) can act as both network formers and modifiers, according to the glass composition. The modifiers (calcium, lead, lithium, sodium, potassium) alter the network structure; they are usually present as ions, compensated by nearby non-bridging oxygen atoms, bound by one covalent bond to the glass network and holding one negative charge to compensate for the positive ion nearby. Some elements can play multiple roles; e.g. lead can act both as a network former (Pb4+ replacing Si4+), or as a modifier.


What type of components change the network's shape?


What type of component can both make and change networks?


What type of chemical attachment connects ions to the network?


What component gives glass the ability to conduct electricity?

The alkali metal ions are small and mobile; their presence in glass allows a degree of electrical conductivity, especially in molten state or at high temperature. Their mobility decreases the chemical resistance of the glass, allowing leaching by water and facilitating corrosion. Alkaline earth ions, with their two positive charges and requirement for two non-bridging oxygen ions to compensate for their charge, are much less mobile themselves and also hinder diffusion of other ions, especially the alkalis. The most common commercial glasses contain both alkali and alkaline earth ions (usually sodium and calcium), for easier processing and satisfying corrosion resistance. Corrosion resistance of glass can be achieved by dealkalization, removal of the alkali ions from the glass surface by reaction with e.g. sulfur or fluorine compounds. Presence of alkaline metal ions has also detrimental effect to the loss tangent of the glass, and to its electrical resistance; glasses for electronics (sealing, vacuum tubes, lamps...) have to take this in account.


How can glass be prevented from corroding?


What types of ions does typical glass have?


Reaction with what causes dealkalization?


What can alkaline ions in glass harm, in addition to electrical resistance?


What material is useful in glassmaking because of its slow evaporation?

New chemical glass compositions or new treatment techniques can be initially investigated in small-scale laboratory experiments. The raw materials for laboratory-scale glass melts are often different from those used in mass production because the cost factor has a low priority. In the laboratory mostly pure chemicals are used. Care must be taken that the raw materials have not reacted with moisture or other chemicals in the environment (such as alkali or alkaline earth metal oxides and hydroxides, or boron oxide), or that the impurities are quantified (loss on ignition). Evaporation losses during glass melting should be considered during the selection of the raw materials, e.g., sodium selenite may be preferred over easily evaporating SeO2. Also, more readily reacting raw materials may be preferred over relatively inert ones, such as Al(OH)3 over Al2O3. Usually, the melts are carried out in platinum crucibles to reduce contamination from the crucible material. Glass homogeneity is achieved by homogenizing the raw materials mixture (glass batch), by stirring the melt, and by crushing and re-melting the first melt. The obtained glass is usually annealed to prevent breakage during processing.


Why are different materials used in a lab than are used in factory production?


What is the reason for crushing the glass and melting it again?


In the past, small batches of amorphous metals with high surface area configurations (ribbons, wires, films, etc.) have been produced through the implementation of extremely rapid rates of cooling. This was initially termed "splat cooling" by doctoral student W. Klement at Caltech, who showed that cooling rates on the order of millions of degrees per second is sufficient to impede the formation of crystals, and the metallic atoms become "locked into" a glassy state. Amorphous metal wires have been produced by sputtering molten metal onto a spinning metal disk. More recently a number of alloys have been produced in layers with thickness exceeding 1 millimeter. These are known as bulk metallic glasses (BMG). Liquidmetal Technologies sell a number of zirconium-based BMGs. Batches of amorphous steel have also been produced that demonstrate mechanical properties far exceeding those found in conventional steel alloys.


What are thick alloys made in layers called?


What does Liquidmetal Technologies use for their alloys?


What type of metal makes better alloys than traditional steel?


At what university was Klement a student?


Who showed that q-glass could be produced from a melt?

In 2004, NIST researchers presented evidence that an isotropic non-crystalline metallic phase (dubbed "q-glass") could be grown from the melt. This phase is the first phase, or "primary phase," to form in the Al-Fe-Si system during rapid cooling. Interestingly, experimental evidence indicates that this phase forms by a first-order transition. Transmission electron microscopy (TEM) images show that the q-glass nucleates from the melt as discrete particles, which grow spherically with a uniform growth rate in all directions. The diffraction pattern shows it to be an isotropic glassy phase. Yet there is a nucleation barrier, which implies an interfacial discontinuity (or internal surface) between the glass and the melt.


What shows that there is an inner surface between glass and melt?


What kind of microscope shows that q-glass grows as separate particles?


What word means that ceramics don't absorb liquids?

Glass-ceramic materials share many properties with both non-crystalline glass and crystalline ceramics. They are formed as a glass, and then partially crystallized by heat treatment. For example, the microstructure of whiteware ceramics frequently contains both amorphous and crystalline phases. Crystalline grains are often embedded within a non-crystalline intergranular phase of grain boundaries. When applied to whiteware ceramics, vitreous means the material has an extremely low permeability to liquids, often but not always water, when determined by a specified test regime.


What materials do glass ceramics have a lot in common with?


How high of a temperature change can glass-ceramics handle?

The term mainly refers to a mix of lithium and aluminosilicates that yields an array of materials with interesting thermomechanical properties. The most commercially important of these have the distinction of being impervious to thermal shock. Thus, glass-ceramics have become extremely useful for countertop cooking. The negative thermal expansion coefficient (CTE) of the crystalline ceramic phase can be balanced with the positive CTE of the glassy phase. At a certain point (~70% crystalline) the glass-ceramic has a net CTE near zero. This type of glass-ceramic exhibits excellent mechanical properties and can sustain repeated and quick temperature changes up to 1000 °C.


Because of their heat resistance, glass-ceramics are especially suitable for what?


What is the most economically significant property of glass-ceramics?


What ingredients give glass-ceramics its useful heat tolerance?


What proportion of crystalline ceramics yields a product with a CTE of around 0?


What were the areas at the center of an old sheet of glass called?

Mass production of glass window panes in the early twentieth century caused a similar effect. In glass factories, molten glass was poured onto a large cooling table and allowed to spread. The resulting glass is thicker at the location of the pour, located at the center of the large sheet. These sheets were cut into smaller window panes with nonuniform thickness, typically with the location of the pour centered in one of the panes (known as "bull's-eyes") for decorative effect. Modern glass intended for windows is produced as float glass and is very uniform in thickness.


In early 20th century glass production, the glass was thickest at what part of the sheet?


What was the benefit of installing glass with the thick side at the bottom, in addition to avoiding water accumulation?

The observation that old windows are sometimes found to be thicker at the bottom than at the top is often offered as supporting evidence for the view that glass flows over a timescale of centuries, the assumption being that the glass has exhibited the liquid property of flowing from one shape to another. This assumption is incorrect, as once solidified, glass stops flowing. The reason for the observation is that in the past, when panes of glass were commonly made by glassblowers, the technique used was to spin molten glass so as to create a round, mostly flat and even plate (the crown glass process, described above). This plate was then cut to fit a window. The pieces were not absolutely flat; the edges of the disk became a different thickness as the glass spun. When installed in a window frame, the glass would be placed with the thicker side down both for the sake of stability and to prevent water accumulating in the lead cames at the bottom of the window. Occasionally such glass has been found installed with the thicker side at the top, left or right.


What is the name for the glassmaking method that involved spinning it into sheets?


The thickness at the bottom of glass panes was once taken as evidence that glass had features of what state of matter?


When does glass stop moving like a liquid?


In physics, the standard definition of a glass (or vitreous solid) is a solid formed by rapid melt quenching. The term glass is often used to describe any amorphous solid that exhibits a glass transition temperature Tg. If the cooling is sufficiently rapid (relative to the characteristic crystallization time) then crystallization is prevented and instead the disordered atomic configuration of the supercooled liquid is frozen into the solid state at Tg. The tendency for a material to form a glass while quenched is called glass-forming ability. This ability can be predicted by the rigidity theory. Generally, the structure of a glass exists in a metastable state with respect to its crystalline form, although in certain circumstances, for example in atactic polymers, there is no crystalline analogue of the amorphous phase.


What is the tendency to make a glass when cooled called?


What must happen quickly for glass to form?


What does glass not have, leading some to think it is a liquid?

Some people consider glass to be a liquid due to its lack of a first-order phase transition where certain thermodynamic variables such as volume, entropy and enthalpy are discontinuous through the glass transition range. The glass transition may be described as analogous to a second-order phase transition where the intensive thermodynamic variables such as the thermal expansivity and heat capacity are discontinuous. Nonetheless, the equilibrium theory of phase transformations does not entirely hold for glass, and hence the glass transition cannot be classed as one of the classical equilibrium phase transformations in solids.


What theory isn't completely valid for glass?


Transition in glass is comparable to what?


Although the atomic structure of glass shares characteristics of the structure in a supercooled liquid, glass tends to behave as a solid below its glass transition temperature. A supercooled liquid behaves as a liquid, but it is below the freezing point of the material, and in some cases will crystallize almost instantly if a crystal is added as a core. The change in heat capacity at a glass transition and a melting transition of comparable materials are typically of the same order of magnitude, indicating that the change in active degrees of freedom is comparable as well. Both in a glass and in a crystal it is mostly only the vibrational degrees of freedom that remain active, whereas rotational and translational motion is arrested. This helps to explain why both crystalline and non-crystalline solids exhibit rigidity on most experimental time scales.


What acts like a liquid but is under the freezing temperature?


Despite its atomic structure, cooled glass acts like what?


In cooled glass, what types of movement stop?


What drives the wider acceptance of renewable energy technologies?

Public policy and political leadership helps to "level the playing field" and drive the wider acceptance of renewable energy technologies. Countries such as Germany, Denmark, and Spain have led the way in implementing innovative policies which has driven most of the growth over the past decade. As of 2014, Germany has a commitment to the "Energiewende" transition to a sustainable energy economy, and Denmark has a commitment to 100% renewable energy by 2050. There are now 144 countries with renewable energy policy targets.


Denmark has a committment to 100 percent renewable energy by what year?


How many countries now have renewable energy policies?


How much was the total investment in renewable energy in 2012?

Total investment in renewable energy (including small hydro-electric projects) was $244 billion in 2012, down 12% from 2011 mainly due to dramatically lower solar prices and weakened US and EU markets. As a share of total investment in power plants, wind and solar PV grew from 14% in 2000 to over 60% in 2012. The top countries for investment in recent years were China, Germany, Spain, the United States, Italy, and Brazil. Renewable energy companies include BrightSource Energy, First Solar, Gamesa, GE Energy, Goldwind, Sinovel, Trina Solar, Vestas and Yingli.


Why did the total investment in renewable energy go down in 2012?


What six were the top countries for investment in recent years?


Who has shown support for ambitious renewable energy goals?

EU member countries have shown support for ambitious renewable energy goals. In 2010, Eurobarometer polled the twenty-seven EU member states about the target "to increase the share of renewable energy in the EU by 20 percent by 2020". Most people in all twenty-seven countries either approved of the target or called for it to go further. Across the EU, 57 percent thought the proposed goal was "about right" and 16 percent thought it was "too modest." In comparison, 19 percent said it was "too ambitious".


What group polled the 27 EU member states in 2010?


The goal was to increase the share of renewable energy in the EU by 20 percent in what year?


By the end of 2011, total renewable power capacity worldwide exceeded what number?

By the end of 2011, total renewable power capacity worldwide exceeded 1,360 GW, up 8%. Renewables producing electricity accounted for almost half of the 208 GW of capacity added globally during 2011. Wind and solar photovoltaics (PV) accounted for almost 40% and 30% . Based on REN21's 2014 report, renewables contributed 19 percent to our energy consumption and 22 percent to our electricity generation in 2012 and 2013, respectively. This energy consumption is divided as 9% coming from traditional biomass, 4.2% as heat energy (non-biomass), 3.8% hydro electricity and 2% electricity from wind, solar, geothermal, and biomass.


Renewables contributed what percentage to our energy consumption?


Renewables contributed what percentage to our electricity generation?


During the five-years from the end of 2004 through 2009, worldwide renewable energy capacity grew at rates of 10–60 percent annually for many technologies. In 2011, UN under-secretary general Achim Steiner said: "The continuing growth in this core segment of the green economy is not happening by chance. The combination of government target-setting, policy support and stimulus funds is underpinning the renewable industry's rise and bringing the much needed transformation of our global energy system within reach." He added: "Renewable energies are expanding both in terms of investment, projects and geographical spread. In doing so, they are making an increasing contribution to combating climate change, countering energy poverty and energy insecurity".


Between what years did worldwide renewable energy capacity grow at rates of 10 to 60 percent annually?


Which group projected that solar plant may produce most of the world's electricity within 50 years?

According to a 2011 projection by the International Energy Agency, solar power plants may produce most of the world's electricity within 50 years, significantly reducing the emissions of greenhouse gases that harm the environment. The IEA has said: "Photovoltaic and solar-thermal plants may meet most of the world's demand for electricity by 2060 – and half of all energy needs – with wind, hydropower and biomass plants supplying much of the remaining generation". "Photovoltaic and concentrated solar power together can become the major source of electricity".


Photovoltaic and solar-thermal plants may meet most of the world's demand for electricity by what year?


Photovoltaic and solar-thermal plants may meet how much of the world's energy needs by 2060?


Who led the world in renewable energy production in 2013?

In 2013, China led the world in renewable energy production, with a total capacity of 378 GW, mainly from hydroelectric and wind power. As of 2014, China leads the world in the production and use of wind power, solar photovoltaic power and smart grid technologies, generating almost as much water, wind and solar energy as all of France and Germany's power plants combined. China's renewable energy sector is growing faster than its fossil fuels and nuclear power capacity. Since 2005, production of solar cells in China has expanded 100-fold. As Chinese renewable manufacturing has grown, the costs of renewable energy technologies have dropped. Innovation has helped, but the main driver of reduced costs has been market expansion.


Since what year has production of solar cells in China expanded 100-fold?


What is the main driver of reduced costs?


What is getting cheaper as a result of technilogical change?

Renewable energy technologies are getting cheaper, through technological change and through the benefits of mass production and market competition. A 2011 IEA report said: "A portfolio of renewable energy technologies is becoming cost-competitive in an increasingly broad range of circumstances, in some cases providing investment opportunities without the need for specific economic support," and added that "cost reductions in critical technologies, such as wind and solar, are set to continue." As of 2011[update], there have been substantial reductions in the cost of solar and wind technologies:


As of what year have there been substantial reductions in the cost of solar and wind technologies?


What group stated that "cost reductions in critical technologies, such as wind and solar, are set to continue?"


What is the most economic solution for new grid-connected capacity in areas with good resources?

Renewable energy is also the most economic solution for new grid-connected capacity in areas with good resources. As the cost of renewable power falls, the scope of economically viable applications increases. Renewable technologies are now often the most economic solution for new generating capacity. Where "oil-fired generation is the predominant power generation source (e.g. on islands, off-grid and in some countries) a lower-cost renewable solution almost always exists today". As of 2012, renewable power generation technologies accounted for around half of all new power generation capacity additions globally. In 2011, additions included 41 gigawatt (GW) of new wind power capacity, 30 GW of PV, 25 GW of hydro-electricity, 6 GW of biomass, 0.5 GW of CSP, and 0.1 GW of geothermal power.


What happens as the scope of economically viable applications increases?


What are now often the most economic solution for new generating capacity?


Biomass for heat and power is a fully mature technology which offers a ready disposal mechanism for municipal, agricultural, and industrial organic wastes. However, the industry has remained relatively stagnant over the decade to 2007, even though demand for biomass (mostly wood) continues to grow in many developing countries. One of the problems of biomass is that material directly combusted in cook stoves produces pollutants, leading to severe health and environmental consequences, although improved cook stove programmes are alleviating some of these effects. First-generation biomass technologies can be economically competitive, but may still require deployment support to overcome public acceptance and small-scale issues.


What can be economically competetive but may still require deployment support?


What is a fully maturing technology which offer a ready disposal mechanismm?


What is the term referring to electricity generated by hydropower?

Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy, accounting for 16 percent of global electricity generation – 3,427 terawatt-hours of electricity production in 2010, and is expected to increase about 3.1% each year for the next 25 years. Hydroelectric plants have the advantage of being long-lived and many existing plants have operated for more than 100 years.


What is the most widely used form of renewable energy?


Hydroelectricity accounts for what percentage of global electricity generation?


Electricity production is expected to increase by what percentage each year for the next 25 years?


Hydropower is produced in how many countries?

Hydropower is produced in 150 countries, with the Asia-Pacific region generating 32 percent of global hydropower in 2010. China is the largest hydroelectricity producer, with 721 terawatt-hours of production in 2010, representing around 17 percent of domestic electricity use. There are now three hydroelectricity plants larger than 10 GW: the Three Gorges Dam in China, Itaipu Dam across the Brazil/Paraguay border, and Guri Dam in Venezuela. The cost of hydroelectricity is low, making it a competitive source of renewable electricity. The average cost of electricity from a hydro plant larger than 10 megawatts is 3 to 5 U.S. cents per kilowatt-hour.


Which country is the largest hydroelectricity producer?


What is the average cost of electricity from a hydro plant larger than 10 megawatts?


How many hydroelectricity plants are larger than 10 GW?


What was the geothermal capacity in 1975?

Geothermal power capacity grew from around 1 GW in 1975 to almost 10 GW in 2008. The United States is the world leader in terms of installed capacity, representing 3.1 GW. Other countries with significant installed capacity include the Philippines (1.9 GW), Indonesia (1.2 GW), Mexico (1.0 GW), Italy (0.8 GW), Iceland (0.6 GW), Japan (0.5 GW), and New Zealand (0.5 GW). In some countries, geothermal power accounts for a significant share of the total electricity supply, such as in the Philippines, where geothermal represented 17 percent of the total power mix at the end of 2008.


What was the geothermal capacity in 2008?


In the Phillipines, geothermal represented what percentage of the total power mix at the end of 2008?


Where have the majority of photovoltaic power stations been built?

Many solar photovoltaic power stations have been built, mainly in Europe. As of July 2012, the largest photovoltaic (PV) power plants in the world are the Agua Caliente Solar Project (USA, 247 MW), Charanka Solar Park (India, 214 MW), Golmud Solar Park (China, 200 MW), Perovo Solar Park (Russia 100 MW), Sarnia Photovoltaic Power Plant (Canada, 97 MW), Brandenburg-Briest Solarpark (Germany 91 MW), Solarpark Finow Tower (Germany 84.7 MW), Montalto di Castro Photovoltaic Power Station (Italy, 84.2 MW), Eggebek Solar Park (Germany 83.6 MW), Senftenberg Solarpark (Germany 82 MW), Finsterwalde Solar Park (Germany, 80.7 MW), Okhotnykovo Solar Park (Russia, 80 MW), Lopburi Solar Farm (Thailand 73.16 MW), Rovigo Photovoltaic Power Plant (Italy, 72 MW), and the Lieberose Photovoltaic Park (Germany, 71.8 MW).


Where is the Agua Caliente Solar Project located?


Where is Desert Sunlight Solar Farm currently under construction?

There are also many large plants under construction. The Desert Sunlight Solar Farm under construction in Riverside County, California and Topaz Solar Farm being built in San Luis Obispo County, California are both 550 MW solar parks that will use thin-film solar photovoltaic modules made by First Solar. The Blythe Solar Power Project is a 500 MW photovoltaic station under construction in Riverside County, California. The California Valley Solar Ranch (CVSR) is a 250 megawatt (MW) solar photovoltaic power plant, which is being built by SunPower in the Carrizo Plain, northeast of California Valley. The 230 MW Antelope Valley Solar Ranch is a First Solar photovoltaic project which is under construction in the Antelope Valley area of the Western Mojave Desert, and due to be completed in 2013. The Mesquite Solar project is a photovoltaic solar power plant being built in Arlington, Maricopa County, Arizona, owned by Sempra Generation. Phase 1 will have a nameplate capacity of 150 megawatts.


Who is building The Califoria Valley Solar Ranch?


Global wind power installations increased by how much in 2010?

Some of the second-generation renewables, such as wind power, have high potential and have already realised relatively low production costs. Global wind power installations increased by 35,800 MW in 2010, bringing total installed capacity up to 194,400 MW, a 22.5% increase on the 158,700 MW installed at the end of 2009. The increase for 2010 represents investments totalling €47.3 billion (US$65 billion) and for the first time more than half of all new wind power was added outside of the traditional markets of Europe and North America, mainly driven, by the continuing boom in China which accounted for nearly half of all of the installations at 16,500 MW. China now has 42,300 MW of wind power installed. Wind power accounts for approximately 19% of electricity generated in Denmark, 9% in Spain and Portugal, and 6% in Germany and the Republic of Ireland. In Australian state of South Australia wind power, championed by Premier Mike Rann (2002–2011), now comprises 26% of the state's electricity generation, edging out coal fired power. At the end of 2011 South Australia, with 7.2% of Australia's population, had 54%of the nation's installed wind power capacity. Wind power's share of worldwide electricity usage at the end of 2014 was 3.1%. These are some of the largest wind farms in the world:


China has how much wind power installed?


In Denmark, wind power accounts for what percentage of electricity generated?


In Spain, wind power accounts for what percentage of electricity generated?


In Germany, wind power accounts for what percentage of electricity generated?


How is the wind industry in the USA able to produce more power at lower cost?

As of 2014, the wind industry in the USA is able to produce more power at lower cost by using taller wind turbines with longer blades, capturing the faster winds at higher elevations. This has opened up new opportunities and in Indiana, Michigan, and Ohio, the price of power from wind turbines built 300 feet to 400 feet above the ground can now compete with conventional fossil fuels like coal. Prices have fallen to about 4 cents per kilowatt-hour in some cases and utilities have been increasing the amount of wind energy in their portfolio, saying it is their cheapest option.


How tall are new wind turbines that are being built in Indiana, Michigan and Ohio?


Wind turbines in the USA can now compete with what type of fuel?


Prices have fallen as low as what price?


Where is the Ivanpah Solar Power Facility located?

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.


What is the world's largest solar-thermal power plant project currently under construction?


Where is the PS20 solar power tower located?


Nearly all gasoline sold in the U.S. is mixed with what percentage of ethanol?

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.


What act calls for 7.5 billion US gallons of biofuels to be used annually by 2012?


Name one company that sells flexible-fuel cars?


What can be made from plant matter composed primarily of inedible celllose fibers thta form the stems and branches of most plants?

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.


What are potential sources of cellulosic biomass?


What is a promising cellulose source that can be sustainably produced in many regions?


As of 2008, geothermal power development was underway in more than how many countries?

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.


What is one new technology attributed to the growth of geothermal power?


What is operational in the USA, Australia, Germany, France and The United Kingdom?


The PV industry has seen drops in module prices since what year?

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.


What is a sign that further price reductions are likely in coming years?


What cost is often regarded as marking the achievment of grid parity for PV?


Why do utility operators often reject renewable resources?

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".


Why do consumers often ignore renewable power systems?


Who argued that some of the problems facing renewable energy are more about culture and institutions than engineering and science?


Lester Brown states that the market does not incorporate what?

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.


Who believes that the market does not value nature's service adequately?


What can help over come the problems with the market?


What involves lowering income taxes while raising levies?

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.


Several Western European companies are shifting taxes in a process known as what?


Besides tax shifting, what is another need?

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.


What was the result of publicly funded links among computers in government labs and reserach institutes?


What helped create the modern wind power industry?


As of 2012, what accounts for about half of new nameplate electrical capacity?

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.


What involves the deployment of three generations of renewable energy technologies dating back more than 100 years?


Name one second-generation technology that is market ready.


What group advocates leveling the playing field?

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.


How does the International Solar Energy Society propse to level the playing field?


What is the key to stabilizing the earth's climate?


What country is reducing its coal subsidy?

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.


What country has been increasing its support for the fossil fuel and nuclear industries?


Some countries have phased out all subsidies for what substance?


Setting national renewable energy targets can be an important part of what?

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.


The European Union has prescribed an indicative renewable energy target of what percent?


Name one outher country with defined national or regional target?


What determines the extent to which renewable energy is to be incorporated into a country's generation mix?

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.


Who has the authority to carry out a number of functions that havae implications for the feasiblity of renewable energy projects?


Why have energy sector regulators become a key facilitator of renewable energy investments?


What is the driving force behind voluntary green electricity within the EU?

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.


What states that EU Member States must ensure that the origin of electricity produced from renewables can be guaranteed?


In the US, what is the main tool to track and stimulate voluntary actions?


What made a strong economic case for investing in low carbon technologies?

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.


In what year did a number of events push renewable energy up the political agenda?


What is driving increasing rates of investment in the renewable energy industry?


What helped the industry weather the 2009 economic crisis better than other sectors?

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.


What suggests that the commercialization of clean energy will hellp countries deal with economic malaise?


Which company became invovled in a political controversy?


What company filed for Chapter 11 bankruptcy?


What plays a major role in the energy mix of many countries?

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.


What is becoming increasingly economic in both developing and devloped countries?


As of 2012, prices for what commodity continued to drop?


Who is United Nations' Secretary-General?

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".


Ban Ki-moon states that renewable energy has the ability to lift the poorest nations to new levels of prosperity?


In 2012, solar electricity consumption increased by what percentage?

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.


Use of wind power in 2012 increased by what percentage?


How much was the worldwide investment in solar power in 2012?


Analysts expect the market to triple by what year?


In what year did investment in renewables exceed fossils?


What motivated the incentive to use 100 percent renewable energy?

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."


How many nations already have renewable energy contributing to more than 20 percent of energy supply?


Who developed a series of stabilization wedges?


Who is a professor of civil and environmental engineering at Stanford University?

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.


What is a barrier to implementing the renewable energy plan?


Who stated that energy costs with a wind, solar, water system should be similar to today's energy costs?


Jacobson says producing all new energy with wind power, solar power and hydropower is feasible by what year?


Why is renewable energy an attractive option?

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." .


In what country is the National Research Council located?


Sufficient domestic reneewable resources exist for what reason?


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.


What name was Palermo originally founded as?


During which years was Palermo ruled by the Arabs?


What types of churches attract tourists to Palermo?

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.


Which town is Sicily's primary industrial and commercial center?


What are Palermo's four main industrial sectors?


What geographic form is Palermo surrounded by?

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".


Which author desribed Monte Pelegrino as "The most beautiful promontory in the world?"


Which is the tallest mountain in Sicily?


Where is Monte Pellegrino in relation to other peaks?


How can former rivers be recognised presently?

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.


What is the only remaining waterway in Palermo?


Which two former rivers in Palermo are currently building sites?


What did Phoenicans name their settlement in 734BC?

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.


Besides Ziz, what other two major settlements belonged to the Phoenicians


Why cant artifacts from the Phoenicians be easily excavated?


What is the current name of the road the Phoenicians used for trading?


Why was the first settlement named Paleapolis?

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.


What were the walls of Neapolis meant to do?


Which district was named for the walls surrounding it?


In which War did Greeks and Phoenicians fight over control of Sicily?

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.


Who conquered Panormos and briefly turned it into a Greek colony?


Why did the Greeks name Palermo Panormos?


How had the Vandals earned their strong reputation?

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.


Whom took control of the Vandal's territory after 488?


How was Theodoric different than the Germanic Goths?


What name was the Eastern Roman Empire also known by?


How long did Muslim control of Palermo last?

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.


What did the Arabs introduce that continues to be relevant to Palermo's culture today?


How were the indigenous Palermo population treated under Muslim rule?


Who is considered a hero by natives for ending Muslim control of Palermo?

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.


What was the family name who returned Palermo to Christianity after reconquest in 1072?


Where was the Kings Court held in the Kingdom of Sicily?


How did the Kingdom of Sicily compare monetarily with the other European staes?


What year did Sicily become ruled by the Holy Roman Empire?

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.


What happened to Muslims during Holy Roman rule?


During what years did Austria rule Palermo?


After what treaty did Savoia gain control of Italy?

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.


For what event did Charles III choose Sicily as the location?


Where did the capital city move in 1817?


Whose son died on the way to Palermo and is buried there?


Who led the first insurrection in Europe in 1848?

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).


Who regained control of Palermo in 1849?


Sicily and Palermo became part of what Kingdom in 1861?


Who was blamed for the week long rebellion of 1866?

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.


Which families help to start cultural, industrial, and economic growth in Palermo?


In what style were the villas in the new expanded Palermo?


Which theatre was designed by Giovan Battista Filippo Basile ans opened in 1897?


To what does the term "Sack of Palermo" refer?

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.


Why did Palermo substancially grow in size?


What is Palermo's climate classification?

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).


How do Palermo's temperatures compare to the rest of Europe?


How many did snow fall in Palermo between 1940and the 2000s?


How much sun does Palermo see each year?


Where does the first of Palermo's circuits suround?

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.


What was the name of the primary east-west road within the walls of Palaeopolis?


On what road was the eastern edge of the walled city?


What was the purpose of Castello a Mare?

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.


What was used to block passage through the La Cala port?


During which historical period was the wall circuit expanded?


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.


What name is given to the bronze line on the floor of a heliometer?


What image is projected on the floor of the heliometer?


How many people were living in the Palermo area in 2010?

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.


What percentage of Palermo residents were female in 2010?


What is the average age of a Palermo resident?


Why has Palermo's population declined from 2001 to 2010?


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.


Has the level of crime in Palermo risen or declined?


What negative qualities does Palermo carry?


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.


How many passengers travel by Palermo ferry annually?


How many passengers do Palermo's ferries carry each year?


For what is the "tourist marina" dedicated?


What cities do the ferries of Palermo travel to?


Who is the popular patron saint of Palermo?

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.


When is Palermo's most important religious event of the year held?


Who is said to have ended the Black Death in 1624?


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).


How many stable isotopes does zinc have?


What other element on the periodic table is zinc similar to?


What is used to extract zinc during the production process?


What two metals are mixed to create Brass?

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".


Where was zinc first produced on a large scale?


Where is the oldest evidence of pure zinc?


The earliest uses of brass has been attributed to what ancient location?


We have evidence of zinc production dating back to the 6th century thanks to what mine?


What early process was used to make zinc?


What were the names given to zinc by early alchemists?


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.


What two people discovered the electrochemical properties of zinc?


Who is credited as giving zinc its name?


How many people are affected by zinc deficiency?

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.


What can consumption of excess zinc cause?


Where can you find enzymes with a zinc atom in the reactive center?


What can a lack of zinc cause in children?


What is extremely important to prenatal and postnatal development?


What can cause symptoms in children ranging from diarrhea to retarded growth?


In what substance can you find a zinc atom within its reactive center?


What causes symptoms such as 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.


At what temperature does the metal become malleable?


At what temperature to zinc become brittle?


In it's pre commercial state, what color is zinc?


What is the crystalline structure of sync?


What happens to zinc when it is manipulated to the temperatures between 100 and 150 Celsius?


At what temperature can zinc be pulverized?


How many radioisotopes of zinc have been discovered?

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.


What is the longest half life of the isotopes?


What is the most long lived radio isotope?


How many nuclear isomers does zinc have?


What does a metastable isotope do to return to ground state from an 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.


what are the only two oxidation states known for zinc?


What oxidation state dominates the chemistry of zinc?


What are the only two oxidation states known for zinc compounds?


Because zinc has a filled d-shell, its compounds are usually what?

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.


The ionic radii of what two elements are almost identical?


What is the determining factor where zinc and magnesium are very similar chemically?


Whit what donors does zinc form stable complexes?


What is necessary to stabilize the low oxidation state of zinc(l) compounds?

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.


What core do most zinc(l) compounds contain?


What confirms the dimeric structure of the compound?


When a solution of metallic zinc is cooled in molten ZnCl2, what is formed?


What is not known for binary compounds of zinc?

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.


ZnO can be dissolved in what kind of solutions?


What applications do chalcogenides have?


Zn(OH)2 is dissolved to form what in strong alkaline solutions?

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).


Zinc oxide is believed to be mentioned in what ancient text?

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.


Active zinc mines in India date back to what period?


What process occurred around the 12th century?


When was the Rasaratna Samuccaya written?


What are the two uses of zinc ore mentioned in the Rasaratna Samuccaya?


Who is attributed as first documenting zinc?

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.


Why is it possible that the name zinc could be derived from the German zinn?


Why would zinc possibly be derived from the German word zinke?


What are some of the other terms for zinc?


Who first patented the process that creates an oxide usable in the retort process?

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.


Before John Champion, what was the only element used to produce zinc?


Who built the first horizontal retort smelter?


What did Galvani name the effect he created of causing the frogs legs to twitch?


The discoveries made by Galvani lead to what three important things?


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%).


What is the first step in zinc metal production?


What percentage of the ore concentrate is zinc?


Large amounts of sulfur dioxide and cadmium vapor are produced due to what?

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.


Smelter slag contains a significant amount of what?


Why does the Geul River contain heavy metals in a significant amount?


What is the ratio that anthropogenic and natural emissions occur at?


What two compounds is zinc more reactive than?

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.


What is used on many common items, such as chain link fences?


What makes zinc an efficient sacrificial anode?

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.


Connecting anodes made from zinc to buried pipe creates what?


What does attaching a zinc disc to a ships iron rudder do?


Why does zinc protect metals exposed to sea water from corroding?


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.


Zinc, copper and aluminum alloys have use in what part of machinery?


Zinc in the main metal used in making which american currency?


What is zinc coated with to influence the look of pennies?


Aside from die casting, what are alloys of zinc mixed with copper, aluminium and magnesium used for?

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.


Alloys of zinc mixed with copper, aluminium and magnesium are marketed as what?


What is possible to produce thanks to the low melting point and low viscosity of zinc aluminium alloy?


What brand name of alloy is supposed to be as strong as steel while still being malleable as plastic?


What can be done when small amounts of lead are added to alloys?

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.


What is made with an alloy of 4% aluminium mixed with 96% zinc?


Why are alloys used to make stamping dies rather than metal?


Why isn't unalloyed zinc used in construction applications?


In what form is 1/4 of zinc used in the US?

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.


What kind of zinc compound is used in manufacturing rubber?


What protects the polymers in rubber from ultraviolet radiation?


Why is zinc oxide useful in photocopying products?


What kind of process is the zinc zinc-oxide cycle?


What is added to wood in order to preserve it?

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.


What is the feature of zinc sufide that makes it useful in television screens?


What kind of lasers are crystals of zinc suflde used in?


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.


Why is zinc oxide used in nuclear reactors?


What is used to study how alloys containing zinc wear out?


What consumable product is zinc included in?

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.


What property of zinc is believed to protect against skin aging?


What is the benefit of zinc after injury?


What kind of cancer cells may zinc prove to kill?

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.


What type of agent is zync useful as against prostate cancer?


What could overuse of zinc possibly cause?


Where does zinc naturally buildup in the body?


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:


What is the zinc equivalent of the Grinard reaction?


When will organomagnesium halide formation fail?


What are dimethylzinc, dietylzinc and diphenylzinc?


What role does zinc play in fingers, twists and clusters?

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.


What are proteins that druing replication and transcription of DNA, recognize base DNA?


How many amino acids do the Zn2+ ions bind to?


What does the transcription factor wrap around?