The 1914 Florida Gators football team represented the University of Florida during the 1914 Southern Intercollegiate Athletic Association football season. The season was C. J. McCoy's first year of three as the head coach of the Gators team.  McCoy's 1914 Florida Gators completed their ninth varsity football season on a four-game winning streak, with an overall record of 5–2  and an SIAA conference record of 3–2.

Before the season
End Joe Swanson was shifted to fullback.

Schedule

Season summary

Auburn

Sources:

Coach Mike Donahue's Auburn team was nearly as strong as the season before, and beat Florida 20–0  en route to another SIAA title. In contrast to last year, the Gators held Auburn scoreless in the first half, and the loss was seen as a moral victory and sign of progress.  However, the Gators also lost their captain. John Sutton left the game feeling poorly, and further examination revealed a weak heart. Roy "Puss" Hancock took over for Sutton as captain.

Auburn's backfield played well and  fullback Bedie Bidez scored two touchdowns. Florida gave way to Auburn's superior weight by the second half.

King College
In the second week of play, Florida enjoyed a first-time victory against the King College Tornado, 36–0.

Sewanee

Sources:

Florida suffered a shutout loss to the Sewanee Tigers, 26–0. Florida was outplayed in the first half. In the final period, Sewanee quarterback Lee Tolley had an 85-yard touchdown run.

The starting lineup was Henderson (left end), Lotspeich (left tackle), Goldsby (left guard), Farrior (center), Yon (right guard), Hancock (right tackle), Freeman (right end), Oates (quarterback), Fuller (left halfback), Sparkman (right halfback), Swanson (fullback).

Florida Southern
In Tampa, Florida extended the winning streak over , 59–0.

Wofford
Florida beat  for the first time, 66–0.

The Citadel

Sources:

In Charleston, the Gators defeated The Citadel 7–0 in a heavy rain and a field saturated with inches of mud.  Rammy Ramsdell returned the opening kickoff back 40 yards, and Jim Sparkman eventually carried it over for the decisive touchdown, "before the ball was wet."

Mercer
Florida closed the season with a 14–0 win over the Mercer Baptists on Thanksgiving.

Postseason
Florida ranked in the top half of the SIAA. The yearbook remarked that a Gator squad had never had more "guts".

Personnel

Linemen

Backfield

Coaching staff
Head coach: Charles J. McCoy
Manager: Ed Embry

References

Bibliography

Florida
Florida Gators football seasons
Florida Gators football

1914 Florida Gators football team


Sourcery is a fantasy novel by British writer Terry Pratchett, the fifth book in his Discworld series, published in 1988.

Premise
On the Discworld, "sourcerers"—wizards who are sources of magic, and thus immensely more powerful than normal wizards—were the main cause of the Great Mage Wars that left areas of the Disc uninhabitable. As eight is a powerful magical number on Discworld, men born as the eighth son of an eighth son are commonly wizards. Since sourcerers are born the eighth son of an eighth son of an eighth son, they are "wizards squared". To prevent the creation of sourcerers, therefore, wizards are not allowed to marry or have children.

There are many references to geasa in the text, which are idiosyncratic curses, vows or obligations placed upon a person (usually a hero, such as Cúchulainn in Irish mythology).

Synopsis
A dying wizard who flouted the rule against having children makes a bargain with Death that allows his spirit to inhabit his staff, which he passes on to his eighth son, who is born a sourcerer.  Under the influence of the staff, this child prodigy travels to Ankh-Morpork and initiates a plan for wizards to rule the Discworld, with himself at their head.  Because the sourcerer's power is threatening to destroy the Discworld altogether, a small band—Rincewind the Wizard, Nijel the Destroyer and Conina the Hairdresser, daughter of Cohen the Barbarian—attempt to thwart those plans.

Plot
Death comes to collect the soul of Ipslore the Red, a wizard who was banished from Unseen University for marrying and having children. Bitter over his exile and the death of his wife, Ipslore vows revenge upon the wizards through his eighth son, Coin. As the eighth son of a wizard, Coin is born a sourcerer, a wizard who generates new magic rather than drawing it from the world, effectively making him the most powerful wizard on the Disc. At the moment of his death, Ipslore transfers his spirit into his wizard's staff, which is passed to Coin, preventing Death from collecting Ipslore's soul (since damaging the staff to do so would kill Coin) and allowing Ipslore to influence his son.

Eight years later, Virrid Wayzygoose, the Archchancellor-designate of Unseen University in Ankh-Morpork, is murdered before his induction by Coin, who then forces his way into the university's Great Hall. After Coin bests one of the top wizards in the University, he is welcomed by the majority of the wizards. Rincewind, The Luggage and the Librarian miss Coin's arrival, having fled the University shortly beforehand after the foreboding departure of all of its magically-influenced pest populations. While they are at the Mended Drum, Conina, a professional thief and a daughter of Discworld legend Cohen the Barbarian, arrives holding a box containing the Archchancellor's hat, which she has procured from the room of Wayzygoose, and which possesses a kind of sentience as a result of being worn by hundreds of Archchancellors. Under the direction of the hat, which sees Coin as a threat to wizardry and the very world, Conina forces Rincewind to come with her and take a boat to the city of Al Khali, where the hat claims there is someone fit to wear it.

In Ankh-Morpork, the wizards are made more powerful due to Coin's presence drawing more magic into the Discworld. Under Coin's direction, the wizards take over Ankh-Morpork—transforming it into a pristine city and turning the Patrician, Lord Vetinari, into a newt—and make plans to take over the world. Elsewhere, Rincewind, Conina and the Luggage end up in the company of Creosote, the seriph of Al Khali, and Abrim, his treacherous vizier. The trio are eventually separated; Rincewind is thrown into the snake pit, where he meets Nijel the Destroyer, a barbarian hero in training. Conina is taken to Creosote's harem, where the Seriph has his concubines tell him stories. The Luggage, having been scorned by Conina, runs away and gets drunk, before killing and eating several creatures in the desert.

Coin eventually declares Unseen University and the various wizarding orders obsolete and orders the Library to be burnt down, claiming that Wizardry no longer requires such things. A group of wizards then attack Al Khali, with the sheer amount of magic created by their arrival temporarily putting Rincewind into a trance and enabling him to use magic, allowing him and Nijel to escape the snake pit. They join up with Creosote and Conina, the latter immediately falling in love with Nijel, and they encounter Abrim, who had put on the Archchancellor's hat hoping to gain power from it, only to be possessed instead. Having the experience of many previous Archchancellors, the hat proves an even match for Sourcery-empowered wizards, fighting off a group of them and enlisting others to its cause. As this takes place, Rincewind, Conina, Nijel and Creosote find a magical flying carpet in the palace's treasury, and use it to escape the palace as it gets destroyed by the possessed Abrim building his own tower.

With the orders no longer around to keep the wizards in check, wizards across the Discworld go to war with one another, threatening to destroy the world completely. Upon hearing Creosote express anti-wizard sentiments, an angry and humiliated Rincewind abandons the group, taking the flying carpet and making his way to the University, where he learns that the Librarian has saved the library books by hiding them in the ancient Tower of Art. The Librarian convinces Rincewind to stop Coin, and he goes off to face the Sourcerer with a sock containing a half-brick. Back in Al Khali, the Luggage, blaming the Archchancellor's hat for everything it has endured, forces its way into Abrim's tower. Distracted by the Luggage, the possessed vizier is killed by the Ankh-Morpork wizards, with the tower and the Archchancellor's hat getting destroyed in the process.

Despite his victory, Coin becomes concerned when he is told that wizards rule under the Discworld Gods. He traps the gods in an alternate reality, which shrinks to become a large pearl, unknowingly causing the Ice Giants, a race of beings who had been imprisoned by the gods, to escape their prison, whereupon they begin strolling across the Discworld, freezing everything in their path. Rincewind confronts Coin soon after this. The Sourcerer is amused, but unthreatened, by Rincewind attempting to fight him, prompting Ipslore to try to force Coin to kill him. Rincewind eventually convinces Coin to throw the staff away, but Ipslore's power is channelled against that of his son. The other wizards leave the tower as Rincewind rushes forward, grabbing the child and sending both of them to the Dungeon Dimensions while Death strikes the staff and takes Ipslore's soul. Rincewind orders Coin to return to the University and, using his other sock filled with sand, attacks the Creatures from the Dungeon Dimensions as a distraction to ensure Coin's escape. The Gods are subsequently set free, stopping the march of the Ice Giants. As the Librarian helps Coin escape, the Luggage charges into the Dungeon Dimensions after Rincewind.

Coin returns the University and Ankh-Morpork to the way they were before he came. After Conina and Nijel travel to the University looking for Rincewind, Coin uses his magic to make them forget him and live happily ever after together. Recognising that he is too powerful to remain in the world, Coin steps into a dimension of his own making and is not seen on the Discworld again. The Librarian takes Rincewind's battered hat, which was left behind when he went into the Dungeon Dimensions, and places it on a pedestal in the Library. The narrator states, "A wizard...will always come back for his hat".

Characters

Marmaric Carding
Coin
Conina
The Luggage
Nijel the Destroyer
Rincewind
Spelter

Adaptations
In 2010, Terry Pratchett stated that Sourcery would be the fifth Discworld novel to be adapted for Sky One, although he had initially wanted to adapt Making Money. However, he thought that it might work better as a film, and that he could have fun with characters like Nijel the Destroyer.

Reception
Critical reception for the novel was positive. Toronto Stars Paul Stuewe writes that Pratchett "demonstrates a flair for cerebral as well as slapstick comedy." A reviewer from Publishers Weekly felt that Sourcery was skillfully written, stating "Pratchett does not merely play with words, he juggles shrewd observations with aplomb." The reviewer added that "the author never takes himself or his message too seriously, and maintains a feather-light touch throughout." Tom Hutchinson, writing for The Times, thought that Sourcery presents a "memorable account of how we adapt power before it adapts us" and "may well be considered [Pratchett's] masterpiece." Thomas M. Wagner from SF Reviews.net gave the book a 3.5/5 rating, commenting that the story "has Pratchett's trademark lightning pacing, and it fires gags and one-liners at you as if from a fully automatic Uzi." He stated that though he found most of Sourcery funny, "it was very evident to me that Pratchett was, at this early stage of the series, barely scratching the surface of what his considerable wit is capable of."

References

External links

 Annotations for Sourcery
 Quotes from Sourcery
 Synopsis of Sourcery

1988 British novels
Discworld books
1988 fantasy novels
Victor Gollancz Ltd books
British comedy novels

Sourcery


Religion in Guinea-Bissau is diverse, with no particular religion comprising an absolute majority of the population. Islam is the most widely professed faith, and significant populations of Christians and adherents of Traditional Faiths are also present in the country.

The CIA World Factbook (2020 estimate) states that around 46.1% of the population are Muslims, 30.6% adhere to Folk religions, 18.9% are Christians, and 4.4% are non-religious or practice other religions. Meanwhile, the US State Department mentions that estimates vary greatly and cites the Pew Forum data (2020) of 46% Muslim, 31% indigenous religious practices, and 19% Christian.

Christians are mostly found along the coastal regions, and belong to the Roman Catholic Church (including Portuguese Bissau-Guineans) and various Protestant denominations.
In 2017, Sunni Islam, including that of Sufi-oriented, were most concentrated in the northern and northeastern parts of the country, while practitioners of traditional indigenous religious beliefs generally live in all but the northern parts of the country.

Islam

Most of Guinea-Bissau's Muslims belong to Sunni Islam and follow Sufi orders. Islam is practiced most widely by the Fula, Soninke, Susu and Mandinka ethnic groups, and Muslims generally live in the north and northeast.

Islam arrived in Guinea-Bissau before the 12th-century with trans-Saharan traders. Initial growth of Islam was limited to the rulers and trading elites of Guinea-Bissau. Major expansion of Islam among the mainstream happened in the 18th and 19th centuries, after the invasion by Biafada kingdom, and the waves of Fulani jihads that arrived from the north led by Musa Ibrahim, Ibrahim Sori, El Hadj Umar Tall and Coli Tenguella.

Christianity

Christianity arrived in Guinea-Bissau with Portuguese traders and missionaries in the 15th century, but only in its coastal regions. Active missionary efforts started only in the 20th century, and in 1977 it became a diocese of the Holy See. Protestant mission arrived in Guinea-Bissau in 1939, and Evangelical Churches have been active through the second half of the 20th century. The Christian missions became a target of destruction during the 1999 civil war in Guinea-Bissau.

According to the 2009 and 1991 censuses of Guinea-Bissau, the practice of Christianity has grown from 15% in 1991 to 22.1% of the total population in 2009; however, Christianity remains concentrated in the coastal regions of the country. Despite the majority of Christian community in Guinea-Bissau belongs to Roman Catholicism recent years there is a significant increase in Protestants and Evangelicals, especially between animist population, because of their missionary work. It is estimated that by 2050 there will be more than 30% Christians in the country as the result of many indigenous people converting to Christianity.

Freedom of religion

The Constitution sees freedom of conscience and religion as inviolable and provides for freedom of worship.

In 2023, the country scored 3 out of 4 for religious freedom.

See also
Christianity in Guinea-Bissau
Islam in Guinea-Bissau
Roman Catholicism in Guinea-Bissau

References

Religion in Guinea-Bissau


The A27 motorway is a motorway in the Netherlands. It is approximately 109 kilometers in length.

The A27 is located in the Dutch provinces North Brabant, South Holland, Utrecht, North Holland, and Flevoland. It connects the city of Breda with Almere. On its way, it passes the cities of Gorinchem, Utrecht and Hilversum.

Route description

'Shared section' with A58 motorway

Although not officially a part of the Rijksweg 27, the section of the A58 motorway between interchanges Galder and Sint-Annabosch is also being referred to as A27, next to the road's official reference number A58.

Technically this situation is incorrect, since the A27's official start is only at interchange Sint-Annabosch.  However, the reference A27 has probably been added to the road signs to help traffic coming from Antwerp in finding their way from the A16 / E19 towards the A27.

European routes

No major European routes follow the A27 motorway. The only one to follow it, is the E311 road between interchange Sint-Annabosch near Breda and interchange Lunetten near Utrecht. This section of the A27 immediately comprises the entire E311 road, since it does not follow any other roads.

Besides, the 'shared section' with the A58 is part of the European route E312.

History
The northernmost section, connecting the town of Huizen with Almere, has been opened in 1999.

Exit list

See also
List of motorways in the Netherlands
List of E-roads in the Netherlands

References

External links

Motorways in the Netherlands
Motorways in Flevoland
Motorways in North Brabant
Motorways in North Holland
Motorways in South Holland
Motorways in Utrecht (province)
Transport in Breda
Transport in Utrecht (city)

A27 motorway (Netherlands)


Sintering or frittage is the process of compacting and forming a solid mass of material by pressure or heat without melting it to the point of liquefaction. Sintering happens as part of a manufacturing process used with metals, ceramics, plastics, and other materials. The nanoparticles in the sintered material diffuse across the boundaries of the particles, fusing the particles together and creating a solid piece.

Since the sintering temperature does not have to reach the melting point of the material, sintering is often chosen as the shaping process for materials with extremely high melting points, such as tungsten and molybdenum. The study of sintering in metallurgical powder-related processes is known as powder metallurgy.

An example of sintering can be observed when ice cubes in a glass of water adhere to each other, which is driven by the temperature difference between the water and the ice. Examples of pressure-driven sintering are the compacting of snowfall to a glacier, or the formation of a hard snowball by pressing loose snow together.

The material produced by sintering is called sinter. The word sinter comes from the Middle High German , a cognate of English cinder.

General sintering

Sintering is generally considered successful when the process reduces porosity and enhances properties such as strength, electrical conductivity, translucency and thermal conductivity. In some special cases, sintering is carefully applied to enhance the strength of a material while preserving porosity (e.g. in filters or catalysts, where gas absorbency is a priority). During the firing process, atomic diffusion drives powder surface elimination in different stages, starting at the formation of necks between powders to final elimination of small pores at the end of the process.

The driving force for densification is the change in free energy from the decrease in surface area and lowering of the surface free energy by the replacement of solid-vapor interfaces. It forms new but lower-energy solid-solid interfaces with a net decrease in total free energy. On a microscopic scale, material transfer is affected by the change in pressure and differences in free energy across the curved surface. If the size of the particle is small (and its curvature is high), these effects become very large in magnitude. The change in energy is much higher when the radius of curvature is less than a few micrometers, which is one of the main reasons why much ceramic technology is based on the use of fine-particle materials.

The ratio of bond area to particle size is a determining factor for properties such as strength and electrical conductivity. To yield the desired bond area, temperature and initial grain size are precisely controlled over the sintering process. At steady state, the particle radius and the vapor pressure are proportional to (p0)2/3 and to (p0)1/3, respectively.

The source of power for solid-state processes is the change in free or chemical potential energy between the neck and the surface of the particle. This energy creates a transfer of material through the fastest means possible; if transfer were to take place from the particle volume or the grain boundary between particles, particle count would decrease and pores would be destroyed. Pore elimination is fastest in samples with many pores of uniform size because the boundary diffusion distance is smallest. during the latter portions of the process, boundary and lattice diffusion from the boundary become important.

Control of temperature is very important to the sintering process, since grain-boundary diffusion and volume diffusion rely heavily upon temperature, particle size, particle distribution, material composition, and often other properties of the sintering environment itself.

Ceramic sintering

Sintering is part of the firing process used in the manufacture of pottery and other ceramic objects. Sintering and vitrification (which requires higher temperatures) are the two the main mechanisms behind the strength and stability of ceramics. Sintered ceramic objects are made from substances such as glass, alumina, zirconia, silica, magnesia, lime, beryllium oxide, and ferric oxide. Some ceramic raw materials have a lower affinity for water and a lower plasticity index than clay, requiring organic additives in the stages before sintering.

Sintering begins when sufficient temperatures have been reached to mobilize the active elements in the ceramic material, which can start below their melting point (typically at 50–80% of their melting point), e.g. as premelting. When sufficient sintering has taken place, the ceramic body will no longer break down in water; additional sintering can reduce the porosity of the ceramic, increase the bond area between ceramic particles, and increase the material strength.

Industrial procedures to create ceramic objects via sintering of powders generally include:

 mixing water, binder, deflocculant, and unfired ceramic powder to form a slurry
spray-drying the slurry
 putting the spray dried powder into a mold and pressing it to form a green body (an unsintered ceramic item)
 heating the green body at low temperature to burn off the binder
 sintering at a high temperature to fuse the ceramic particles together.

All the characteristic temperatures associated with phase transformation, glass transitions, and melting points, occurring during a sinterisation cycle of a particular ceramic's formulation (i.e., tails and frits) can be easily obtained by observing the expansion-temperature curves during optical dilatometer thermal analysis. In fact, sinterisation is associated with a remarkable shrinkage of the material because glass phases flow once their transition temperature is reached, and start consolidating the powdery structure and considerably reducing the porosity of the material.

Sintering is performed at high temperature. Additionally, a second and/or third external force (such as pressure, electric current) could be used. A commonly used second external force is pressure. Sintering performed by only heating is generally termed "pressureless sintering", which is possible with graded metal-ceramic composites, utilising a nanoparticle sintering aid and bulk molding technology. A variant used for 3D shapes is called hot isostatic pressing.

To allow efficient stacking of product in the furnace during sintering and to prevent parts sticking together, many manufacturers separate ware using ceramic powder separator sheets. These sheets are available in various materials such as alumina, zirconia and magnesia. They are additionally categorized by fine, medium and coarse particle sizes. By matching the material and particle size to the ware being sintered, surface damage and contamination can be reduced while maximizing furnace loading.

Sintering of metallic powders

Most, if not all, metals can be sintered. This applies especially to pure metals produced in vacuum which suffer no surface contamination. Sintering under atmospheric pressure requires the use of a protective gas, quite often endothermic gas. Sintering, with subsequent reworking, can produce a great range of material properties. Changes in density, alloying, and heat treatments can alter the physical characteristics of various products. For instance, the Young's modulus En of sintered iron powders remains somewhat insensitive to sintering time, alloying, or particle size in the original powder for lower sintering temperatures, but depends upon the density of the final product:

where D is the density, E is Young's modulus and d is the maximum density of iron.

Sintering is static when a metal powder under certain external conditions may exhibit coalescence, and yet reverts to its normal behavior when such conditions are removed. In most cases, the density of a collection of grains increases as material flows into voids, causing a decrease in overall volume. Mass movements that occur during sintering consist of the reduction of total porosity by repacking, followed by material transport due to evaporation and condensation from diffusion. In the final stages, metal atoms move along crystal boundaries to the walls of internal pores, redistributing mass from the internal bulk of the object and smoothing pore walls. Surface tension is the driving force for this movement.

A special form of sintering (which is still considered part of powder metallurgy) is liquid-state sintering in which at least one but not all elements are in a liquid state. Liquid-state sintering is required for making cemented carbide and tungsten carbide.

Sintered bronze in particular is frequently used as a material for bearings, since its porosity allows lubricants to flow through it or remain captured within it. Sintered copper may be used as a wicking structure in certain types of heat pipe construction, where the porosity allows a liquid agent to move through the porous material via capillary action. For materials that have high melting points such as molybdenum, tungsten, rhenium, tantalum, osmium and carbon, sintering is one of the few viable manufacturing processes. In these cases, very low porosity is desirable and can often be achieved.

Sintered metal powder is used to make frangible shotgun shells called breaching rounds, as used by military and SWAT teams to quickly force entry into a locked room. These shotgun shells are designed to destroy door deadbolts, locks and hinges without risking lives by ricocheting or by flying on at lethal speed through the door. They work by destroying the object they hit and then dispersing into a relatively harmless powder.

Sintered bronze and stainless steel are used as filter materials in applications requiring high temperature resistance while retaining the ability to regenerate the filter element. For example, sintered stainless steel elements are employed for filtering steam in food and pharmaceutical applications, and sintered bronze in aircraft hydraulic systems.

Sintering of powders containing precious metals such as silver and gold is used to make small jewelry items. Evaporative self-assembly of colloidal silver nanocubes into supercrystals has been shown to allow the sintering of electrical joints at temperatures lower than 200°C.

Advantages
Particular advantages of the powder technology include:

 Very high levels of purity and uniformity in starting materials
 Preservation of purity, due to the simpler subsequent fabrication process (fewer steps) that it makes possible
 Stabilization of the details of repetitive operations, by control of grain size during the input stages
 Absence of binding contact between segregated powder particles – or "inclusions" (called stringering) – as often occurs in melting processes
 No deformation needed to produce directional elongation of grains
 Capability to produce materials of controlled, uniform porosity.
 Capability to produce nearly net-shaped objects.
 Capability to produce materials which cannot be produced by any other technology.
 Capability to fabricate high-strength material like turbine blades.
 After sintering the mechanical strength to handling becomes higher.

The literature contains many references on sintering dissimilar materials to produce solid/solid-phase compounds or solid/melt mixtures at the processing stage. Almost any substance can be obtained in powder form, through either chemical, mechanical or physical processes, so basically any material can be obtained through sintering. When pure elements are sintered, the leftover powder is still pure, so it can be recycled.

Disadvantages
Particular disadvantages of the powder technology include:

 100% sintered (iron ore) cannot be charged in the blast furnace
 sintering cannot create uniform sizes
 micro- and nanostructures produced before sintering are often destroyed.

Plastics sintering
Plastic materials are formed by sintering for applications that require materials of specific porosity. Sintered plastic porous components are used in filtration and to control fluid and gas flows. Sintered plastics are used in applications requiring caustic fluid separation processes such as the nibs in whiteboard markers, inhaler filters, and vents for caps and liners on packaging materials. Sintered ultra high molecular weight polyethylene materials are used as ski and snowboard base materials. The porous texture allows wax to be retained within the structure of the base material, thus providing a more durable wax coating.

Liquid phase sintering
For materials that are difficult to sinter, a process called liquid phase sintering is commonly used. Materials for which liquid phase sintering is common are Si3N4, WC, SiC, and more. Liquid phase sintering is the process of adding an additive to the powder which will melt before the matrix phase. The process of liquid phase sintering has three stages:

rearrangement – As the liquid melts capillary action will pull the liquid into pores and also cause grains to rearrange into a more favorable packing arrangement.
solution-precipitation – In areas where capillary pressures are high (particles are close together) atoms will preferentially go into solution and then precipitate in areas of lower chemical potential where particles are not close or in contact. This is called contact flattening. This densifies the system in a way similar to grain boundary diffusion in solid state sintering. Ostwald ripening will also occur where smaller particles will go into solution preferentially and precipitate on larger particles leading to densification.
final densification – densification of solid skeletal network, liquid movement from efficiently packed regions into pores.

For liquid phase sintering to be practical the major phase should be at least slightly soluble in the liquid phase and the additive should melt before any major sintering of the solid particulate network occurs, otherwise rearrangement of grains will not occur. Liquid phase sintering was successfully applied to improve grain growth of thin semiconductor layers from nanoparticle precursor films.

Electric current assisted sintering
These techniques employ electric currents to drive or enhance sintering. English engineer A. G. Bloxam registered in 1906 the first patent on sintering powders using direct current in vacuum. The primary purpose of his inventions was the industrial scale production of filaments for incandescent lamps by compacting tungsten or molybdenum particles. The applied current was particularly effective in reducing surface oxides that increased the emissivity of the filaments.

In 1913, Weintraub and Rush patented a modified sintering method which combined electric current with pressure. The benefits of this method were proved for the sintering of refractory metals as well as conductive carbide or nitride powders. The starting boron–carbon or silicon–carbon powders were placed in an electrically insulating tube and compressed by two rods which also served as electrodes for the current. The estimated sintering temperature was 2000 °C.

In the United States, sintering was first patented by Duval d'Adrian in 1922. His three-step process aimed at producing heat-resistant blocks from such oxide materials as zirconia, thoria or tantalia. The steps were: (i) molding the powder; (ii) annealing it at about 2500 °C to make it conducting; (iii) applying current-pressure sintering as in the method by Weintraub and Rush.

Sintering that uses an arc produced via a capacitance discharge to eliminate oxides before direct current heating, was patented by G. F. Taylor in 1932. This originated sintering methods employing pulsed or alternating current, eventually superimposed to a direct current. Those techniques have been developed over many decades and summarized in more than 640 patents.

Of these technologies the most well known is resistance sintering (also called hot pressing) and spark plasma sintering, while electro sinter forging is the latest advancement in this field.

Spark plasma sintering
In spark plasma sintering (SPS), external pressure and an electric field are applied simultaneously to enhance the densification of the metallic/ceramic powder compacts. However, after commercialization it was determined there is no plasma, so the proper name is spark sintering as coined by Lenel. The electric field driven densification supplements sintering with a form of hot pressing, to enable lower temperatures and taking less time than typical sintering. For a number of years, it was speculated that the existence of sparks or plasma between particles could aid sintering; however, Hulbert and coworkers systematically proved that the electric parameters used during spark plasma sintering make it (highly) unlikely.  In light of this, the name "spark plasma sintering" has been rendered obsolete. Terms such as field assisted sintering technique (FAST), electric field assisted sintering (EFAS), and direct current sintering (DCS) have been implemented by the sintering community. Using a direct current (DC) pulse as the electric current, spark plasma, spark impact pressure, joule heating, and an electrical field diffusion effect would be created. By modifying the graphite die design and its assembly, it is possible to perform pressureless sintering in spark plasma sintering facility. This modified die design setup is reported to synergize the advantages of both conventional pressureless sintering and spark plasma sintering techniques.

Electro sinter forging
Electro sinter forging is an electric current assisted sintering (ECAS) technology originated from capacitor discharge sintering. It is used for the production of diamond metal matrix composites and is under evaluation for the production of hard metals, nitinol and other metals and intermetallics. It is characterized by a very low sintering time, allowing machines to sinter at the same speed as a compaction press.

Pressureless sintering
Pressureless sintering is the sintering of a powder compact (sometimes at very high temperatures, depending on the powder) without applied pressure. This avoids density variations in the final component, which occurs with more traditional hot pressing methods.

The powder compact (if a ceramic) can be created by slip casting, injection moulding, and cold isostatic pressing. After presintering, the final green compact can be machined to its final shape before being sintered.

Three different heating schedules can be performed with pressureless sintering: constant-rate of heating (CRH), rate-controlled sintering (RCS), and two-step sintering (TSS). The microstructure and grain size of the ceramics may vary depending on the material and method used.

Constant-rate of heating (CRH), also known as temperature-controlled sintering, consists of heating the green compact at a constant rate up to the sintering temperature. Experiments with zirconia have been performed to optimize the sintering temperature and sintering rate for CRH method. Results showed that the grain sizes were identical when the samples were sintered to the same density, proving that grain size is a function of specimen density rather than CRH temperature mode.

In rate-controlled sintering (RCS), the densification rate in the open-porosity phase is lower than in the CRH method. By definition, the relative density, ρrel, in the open-porosity phase is lower than 90%. Although this should prevent separation of pores from grain boundaries, it has been proven statistically that RCS did not produce smaller grain sizes than CRH for alumina, zirconia, and ceria samples.

Two-step sintering (TSS) uses two different sintering temperatures. The first sintering temperature should guarantee a relative density higher than 75% of theoretical sample density. This will remove supercritical pores from the body. The sample will then be cooled down and held at the second sintering temperature until densification is completed. Grains of cubic zirconia and cubic strontium titanate were significantly refined by TSS compared to CRH. However, the grain size changes in other ceramic materials, like tetragonal zirconia and hexagonal alumina, were not statistically significant.

Microwave sintering
In microwave sintering, heat is sometimes generated internally within the material, rather than via surface radiative heat transfer from an external heat source. Some materials fail to couple and others exhibit run-away behavior, so it is restricted in usefulness. A benefit of microwave sintering is faster heating for small loads, meaning less time is needed to reach the sintering temperature, less heating energy is required and there are improvements in the product properties.

A failing of microwave sintering is that it generally sinters only one compact at a time, so overall productivity turns out to be poor except for situations involving one of a kind sintering, such as for artists. As microwaves can only penetrate a short distance in materials with a high conductivity and a high permeability, microwave sintering requires the sample to be delivered in powders with a particle size around the penetration depth of microwaves in the particular material. The sintering process and side-reactions run several times faster during microwave sintering at the same temperature, which results in different properties for the sintered product.

This technique is acknowledged to be quite effective in maintaining fine grains/nano sized grains in sintered bioceramics. Magnesium phosphates and calcium phosphates are the examples which have been processed through the microwave sintering technique.

Densification, vitrification and grain growth
Sintering in practice is the control of both densification and grain growth. Densification is the act of reducing porosity in a sample, thereby making it denser. Grain growth is the process of grain boundary motion and Ostwald ripening to increase the average grain size. Many properties (mechanical strength, electrical breakdown strength, etc.) benefit from both a high relative density and a small grain size. Therefore, being able to control these properties during processing is of high technical importance. Since densification of powders requires high temperatures, grain growth naturally occurs during sintering. Reduction of this process is key for many engineering ceramics. Under certain conditions of chemistry and orientation, some grains may grow rapidly at the expense of their neighbours during sintering. This phenomenon, known as abnormal grain growth (AGG), results in a bimodal grain size distribution that has consequences for the mechanical, dielectric and thermal performance of the sintered material.

For densification to occur at a quick pace it is essential to have (1) an amount of liquid phase that is large in size, (2) a near complete solubility of the solid in the liquid, and (3) wetting of the solid by the liquid. The power behind the densification is derived from the capillary pressure of the liquid phase located between the fine solid particles. When the liquid phase wets the solid particles, each space between the particles becomes a capillary in which a substantial capillary pressure is developed. For submicrometre particle sizes, capillaries with diameters in the range of 0.1 to 1 micrometres develop pressures in the range of  to  for silicate liquids and in the range of  to  for a metal such as liquid cobalt.

Densification requires constant capillary pressure where just solution-precipitation material transfer would not produce densification. For further densification, additional particle movement while the particle undergoes grain-growth and grain-shape changes occurs. Shrinkage would result when the liquid slips between particles and increases pressure at points of contact causing the material to move away from the contact areas, forcing particle centers to draw near each other.

The sintering of liquid-phase materials involves a fine-grained solid phase to create the needed capillary pressures proportional to its diameter, and the liquid concentration must also create the required capillary pressure within range, else the process ceases. The vitrification rate is dependent upon the pore size, the viscosity and amount of liquid phase present leading to the viscosity of the overall composition, and the surface tension. Temperature dependence for densification controls the process because at higher temperatures viscosity decreases and increases liquid content. Therefore, when changes to the composition and processing are made, it will affect the vitrification process.

Sintering mechanisms
Sintering occurs by diffusion of atoms through the microstructure. This diffusion is caused by a gradient of chemical potential – atoms move from an area of higher chemical potential to an area of lower chemical potential. The different paths the atoms take to get from one spot to another are the "sintering mechanisms" or "matter transport mechanisms".

In solid state sintering, the six common mechanisms are:

 surface diffusion – diffusion of atoms along the surface of a particle
 vapor transport – evaporation of atoms which condense on a different surface
 lattice diffusion from surface – atoms from surface diffuse through lattice
 lattice diffusion from grain boundary – atom from grain boundary diffuses through lattice
 grain boundary diffusion – atoms diffuse along grain boundary
 plastic deformation – dislocation motion causes flow of matter.

Mechanisms 1–3 above are non-densifying (i.e. do not cause the pores and the overall ceramic body to shrink) but can still increase the area of the bond or "neck" between grains; they take atoms from the surface and rearrange them onto another surface or part of the same surface. Mechanisms 4–6 are densifying – atoms are moved from the bulk material or the grain boundaries to the surface of pores, thereby eliminating porosity and increasing the density of the sample.

Grain growth

A grain boundary (GB) is the transition area or interface between adjacent crystallites (or grains) of the same chemical and lattice composition, not to be confused with a phase boundary. The adjacent grains do not have the same orientation of the lattice, thus giving the atoms in GB shifted positions relative to the lattice in the crystals. Due to the shifted positioning of the atoms in the GB they have a higher energy state when compared with the atoms in the crystal lattice of the grains. It is this imperfection that makes it possible to selectively etch the GBs when one wants the microstructure to be visible.

Striving to minimize its energy leads to the coarsening of the microstructure to reach a metastable state within the specimen. This involves minimizing its GB area and changing its topological structure to minimize its energy. This grain growth can either be normal or abnormal, a normal grain growth is characterized by the uniform growth and size of all the grains in the specimen. Abnormal grain growth is when a few grains grow much larger than the remaining majority.

Grain boundary energy/tension
The atoms in the GB are normally in a higher energy state than their equivalent in the bulk material. This is due to their more stretched bonds, which gives rise to a GB tension . This extra energy that the atoms possess is called the grain boundary energy,  . The grain will want to minimize this extra energy, thus striving to make the grain boundary area smaller and this change requires energy.

"Or, in other words, a force has to be applied, in the plane of the grain boundary and acting along a line in the grain-boundary area, in order to extend the grain-boundary area in the direction of the force. The force per unit length, i.e. tension/stress, along the line mentioned is σGB. On the basis of this reasoning it would follow that:

with dA as the increase of grain-boundary area per unit length along the line in the grain-boundary area considered."[pg 478]

The GB tension can also be thought of as the attractive forces between the atoms at the surface and the tension between these atoms is due to the fact that there is a larger interatomic distance between them at the surface compared to the bulk (i.e. surface tension). When the surface area becomes bigger the bonds stretch more and the GB tension increases. To counteract this increase in tension there must be a transport of atoms to the surface keeping the GB tension constant. This diffusion of atoms accounts for the constant surface tension in liquids. Then the argument,

holds true. For solids, on the other hand, diffusion of atoms to the surface might not be sufficient and the surface tension can vary with an increase in surface area.

For a solid, one can derive an expression for the change in Gibbs free energy, dG, upon the change of GB area, dA. dG is given by

which gives

 is normally expressed in units of  while  is normally expressed in units of   since they are different physical properties.

Mechanical equilibrium
In a two-dimensional isotropic material the grain boundary tension would be the same for the grains. This would give angle of 120° at GB junction where three grains meet. This would give the structure a hexagonal pattern which is the metastable state (or mechanical equilibrium) of the 2D specimen. A consequence of this is that, to keep trying to be as close to the equilibrium as possible, grains with fewer sides than six will bend the GB to try keep the 120° angle between each other. This results in a curved boundary with its curvature towards itself. A grain with six sides will, as mentioned, have straight boundaries, while a grain with more than six sides will have curved boundaries with its curvature away from itself. A grain with six boundaries (i.e. hexagonal structure) is in a metastable state (i.e. local equilibrium) within the 2D structure.  In three dimensions structural details are similar but much more complex and the metastable structure for a grain is a non-regular 14-sided polyhedra with doubly curved faces. In practice all arrays of grains are always unstable and thus always grow until prevented by a counterforce.

Grains strive to minimize their energy, and a curved boundary has a higher energy than a straight boundary. This means that the grain boundary will migrate towards the  curvature. The consequence of this is that grains with less than 6 sides will decrease in size while grains with more than 6 sides will increase in size.

Grain growth occurs due to motion of atoms across a grain boundary. Convex surfaces have a higher chemical potential than concave surfaces, therefore grain boundaries will move toward their center of curvature. As smaller particles tend to have a higher radius of curvature and this results in smaller grains losing atoms to larger grains and shrinking. This is a process called Ostwald ripening. Large grains grow at the expense of small grains.

Grain growth in a simple model is found to follow:

Here G is final average grain size, G0 is the initial average grain size, t is time, m is a factor between 2 and 4, and K is a factor given by:

Here Q is the molar activation energy, R is the ideal gas constant, T is absolute temperature, and K0 is a material dependent factor. In most materials the sintered grain size is proportion to the inverse square root of the fractional porosity, implying that pores are the most effective retardant for grain growth during sintering.

Reducing grain growth

Solute ions
If a dopant is added to the material (example: Nd in BaTiO3) the impurity will tend to stick to the grain boundaries. As the grain boundary tries to move (as atoms jump from the convex to concave surface) the change in concentration of the dopant at the grain boundary will impose a drag on the boundary. The original concentration of solute around the grain boundary will be asymmetrical in most cases. As the grain boundary tries to move, the concentration on the side opposite of motion will have a higher concentration and therefore have a higher chemical potential. This increased chemical potential will act as a backforce to the original chemical potential gradient that is the reason for grain boundary movement. This decrease in net chemical potential will decrease the grain boundary velocity and therefore grain growth.

Fine second phase particles
If particles of a second phase which are insoluble in the matrix phase are added to the powder in the form of a much finer powder, then this will decrease grain boundary movement. When the grain boundary tries to move past the inclusion diffusion of atoms from one grain to the other, it will be hindered by the insoluble particle. This is because it is beneficial for particles to reside in the grain boundaries and they exert a force in opposite direction compared to grain boundary migration. This effect is called the Zener effect after the man who estimated this drag force to

where r is the radius of the particle and λ the interfacial energy of the boundary if there are N particles per unit volume their volume fraction f is

assuming they are randomly distributed. A boundary of unit area will intersect all particles within a volume of 2r which is 2Nr particles. So the number of particles n intersecting a unit area of grain boundary is:

Now, assuming that the grains only grow due to the influence of curvature, the driving force of growth is  where (for homogeneous grain structure) R approximates to the mean diameter of the grains. With this the critical diameter that has to be reached before the grains ceases to grow:

This can be reduced to

so the critical diameter of the grains is  dependent on the size and volume fraction of the particles at the grain boundaries.

It has also been shown that small bubbles or cavities can act as inclusion

More complicated interactions which slow grain boundary motion include interactions of the surface energies of the two grains and the inclusion and are discussed in detail by C.S. Smith.

Sintering of catalysts
Sintering is an important cause for loss of catalytic activity, especially on supported metal catalysts. It decreases the surface area of the catalyst and changes the surface structure. For a porous catalytic surface, the pores may collapse due to sintering, resulting in loss of surface area. Sintering is in general an irreversible process.

Small catalyst particles have the highest possible relative surface area and high reaction temperature, both factors that generally increase the reactivity of a catalyst. However, these factors are also the circumstances under which sintering occurs. Specific materials may also increase the rate of sintering. On the other hand, by alloying catalysts with other materials, sintering can be reduced. Rare-earth metals in particular have been shown to reduce sintering of metal catalysts when alloyed.

For many supported metal catalysts, sintering starts to become a significant effect at temperatures over . Catalysts that operate at higher temperatures, such as a car catalyst, use structural improvements to reduce or prevent sintering. These improvements are in general in the form of a support made from an inert and thermally stable material such as silica, carbon or alumina.

See also

, a rapid prototyping technology, that includes Direct Metal Laser Sintering (DMLS).

 – a pioneer of sintering methods

References

Further reading

External links

Particle-Particle-Sintering – a 3D lattice kinetic Monte Carlo simulation
Sphere-Plate-Sintering – a 3D lattice kinetic Monte Carlo simulation

Industrial processes
Metalworking
Plastics industry
Metallurgical processes

Sintering


Rdeysky Nature Reserve, Rdeysky Zapovednik () is a nature reserve (a zapovednik)  in the northwest of Russia, located in Poddorsky and Kholmsky Districts of Novgorod Oblast, in the Polist-Lovat Swamp System.  The reserve is about 180 km southeast of the city of Pskov.  It was established on May 25, 1994. The nature reserve is created to protect the raised bog ecosystems of the Northwestern Russia.

Location and geography
The area of the reserve is elongated from southeast to northwest and is adjacent to the border between Novgorod and Pskov Oblasts. At the other side of the border, in Pskov Oblast, the nature reserve continues as Polistovsky Nature Reserve. Rdeysky Nature Reserve belongs to the river basins of the Lovat River and the Polist River, though none of them flows through the reserve. Lake Rdeyskoye, a major lake at the northwest of the reserve of which a part of the shore belongs to the reserve, is the source of the Redya River, a major left tributary of the Lovat River.

History
There are currently no villages at the territory of the reserve; however, in the past it was populated, and the last village existed until World War II. The villages were located on islands in the middle of the swamp, and their inhabitants were collecting timber. Small-scale timber production was continuing after the war as well, but the area was too remote to support the settlements. No irrigation work has ever been performed in the area, and the raised bogs remain intact. In 1994, both Rdeysky and Polistovsky Nature Reserves were established to protect the area.

Ecoregion and climate
The reserve is located in one of the most southerly locations of the Scandinavian and Russian taiga ecoregion.  This ecoregion is situated in Northern Europe between tundra in the north and temperate mixed forests in the south.  The climate is Humid continental climate, warm summer (Köppen climate classification (Dfb)). This climate is characterized by large swings in temperature, both diurnally and seasonally, with mild summers and cold, snowy winters

Flora
The area mostly consists of raised bogs. Forest grows on the islands on the bog. The main types forest are coniferous forests based on spruce and broadleaf forest, based on oak and linden. Birch and aspen appeared as derivative forest from oak and linden. Around 400 species of plants grow in the reserve.

Fauna
European mink is a critically endangered mammal species which is resident in the reserve. The reserve hosts the largest population of Eurasian curlew in Europe.

References

External links
  Map of Rydesky, from OpenStreetMap.org

Geography of Novgorod Oblast
Nature reserves in Russia
Protected areas established in 1994
1994 establishments in Russia
Zapovednik

Rdeysky Nature Reserve


The National Reconstruction Front (Front pour la Reconstruction Nationale, FRN)  is a political party in Haiti. In the presidential elections of 7 February 2006, its candidate Guy Philippe won 1,97% of the popular vote. The party won in the 7 February 2006 Senate elections 2.4% of the popular vote and no Senators. In the 7 February and 21 April 2006 Chamber of Deputies elections, the party won 1 out of 99 seats.

Political parties in Haiti

National Reconstruction Front


Curitiba () is the capital and largest city in the state of Paraná in Southern Brazil. The city's population was 1,963,726 , making it the eighth most populous city in Brazil and the largest in Brazil's South Region. The Curitiba Metropolitan area comprises 29 municipalities with a total population of over 3,731,769 (IBGE estimate in 2021), making it the ninth most populous metropolitan area in the country.

The city sits on a plateau at  above sea level. It is located west of the seaport of Paranaguá and is served by the Afonso Pena International and Bacacheri airports. Curitiba is an important cultural, political, and economic center in Latin America and hosts the Federal University of Paraná, established in 1912.

In the 19th century, Curitiba's favorable location between cattle-breeding countryside and marketplaces led to a successful cattle trade and the city's first major expansion. Later, between 1850 and 1950, it grew due to logging and agricultural expansion in Paraná State (first Araucaria angustifolia logging, later mate and coffee cultivation and in the 1970s wheat, corn and soybean cultivation). In the 1850s, waves of European immigrants arrived in Curitiba, mainly Germans, Italians, Poles and Ukrainians, contributing to the city's economic and cultural development and richness in diversity. Nowadays, only small numbers of immigrants arrive, primarily from Middle Eastern and other South American countries.

Curitiba's biggest expansion occurred after the 1960s, with innovative urban planning that allowed the population to grow from some hundreds of thousands to more than a million people. Curitiba's economy is based on industry and services and is the fourth largest in Brazil. Economic growth occurred in parallel to a substantial inward flow of Brazilians from other parts of the country, as approximately half of the city's population was not born in Curitiba.

Curitiba is one of the few Brazilian cities with a very high Human Development Index (0.856) and in 2010 it was awarded the Global Sustainable City Award, given to cities and municipalities that excel in sustainable urban development. According to US magazine Reader's Digest, Curitiba is the best "Brazilian Big City" in which to live. Curitiba's crime rate is considered low by Brazilian standards and the city is considered one of the safest cities in Brazil for youth. The city is also regarded as the best in which to invest in Brazil. Curitiba was one of the host cities of the 1950 FIFA World Cup, and again for the 2014 FIFA World Cup. Despite its good social indicators, the city has a higher unemployment rate than other cities in the state.

Etymology
One theory is that the name Curitiba comes from the Tupi words kurí tyba 'many araucária seeds' due to the large number of Paraná pines pinecones in the region prior to its founding.

Another version, also using words from the Tupi language, is that it originates in the combination of kurit 'pine tree' and yba 'large amount'.

The Portuguese, who founded a settlement on the site in 1693, named it Vila da Nossa Senhora da Luz dos Pinhais 'Village of Our Lady of the Light of the Pines'.

The name was changed to Curitiba in 1721. Curitiba officially became a town in 1812, spelling its name Curityba.

An alternative spelling was Coritiba. This was used in press and state documents. A state decree in 1919 settled the dispute by adopting Curitiba.

History

At the end of the 17th century, Curitiba's agriculture was only for subsistence and its main economic activities were mineral extraction. Waves of European immigrants arrived after 1850, mainly Poles, Italians, Germans (mostly Volga Germans from Russia) and Ukrainians.

Cattlemen drove their herds from Rio Grande do Sul to the state of São Paulo, turning Curitiba into an important intermediate trading post.

The Paranaguá–Curitiba railroad was opened in 1885.

Around the beginning of the 20th century, Curitiba benefited from the wealth of the yerba mate mills. The owners (known as "barões da erva-mate") built mansions in the capital. These have mostly been preserved in the districts of Batel and Alto da Glória.

In the 1940s and 1950s, Alfred Agache, co-founder of the French Society for Urban Studies, was hired to produce its first city plan. It emphasized a "star" of boulevards, with public amenities downtown, an industrial district and sanitation. It was followed in part, but the plan was too expensive to complete.

Geography
Curitiba, the capital of the Paraná state of southern Brazil, is located near the Atlantic margin of the Brazilian Highlands and the headwaters of the Iguaçu River. It is around 3,050 feet (930 meters) above sea level.

Climate

Curitiba has a typically humid subtropical highland climate (Köppen: Cfb), with some characteristics of the oceanic climate due to its abundant precipitation all year round and the relatively warm, but not hot, summer. The city's mild winters, due to its low latitude, differentiate its climate from typically temperate ones. It is located on a plateau and the flat terrain with flooded areas contribute to its mild and damp winter, with an average minimum temperature of  in July. Temperatures can drop below  on the coldest days. Daytime temperatures in winter are usually pleasant, around . However, during cold snaps, daytime temperatures might not rise above , and on rare occasions, above . During summertime, the average temperature is around  at daytime, but it can get above  on the hottest days. However, temperatures above  at night are rare. Snowfall was experienced in 1889, 1892, 1912, 1928 (two days), 1942, 1955, 1957, 1962, 1975, 1988, 2013 and 2020. Accumulation, however, is much rarer. It was last recorded in 1975.

The terrain's flatness hinders water drainage after rain, therefore providing water vapor for the atmosphere. Cold fronts come year round, often from Antarctica and Argentina, bringing tropical storms in summer and cold winds and frost in the winter. They can move very quickly, with no more than one day between the start of the southern winds and the start of rain. Curitiba's weather is also influenced by the dry air masses that dominate Brazil's midwest most of the year, bringing hot and dry weather, sometimes even in winter.

Vegetation

Curitiba is located in the area of the Ombrophilous Mixed Forest (also known as Araucaria moist forests), a sub-type of the Atlantic Forest. In Curitiba it is possible to find steppes, forests and other formations. The local vegetation consists of remnants of the Paraná (or Brazilian) pine (Araucaria angustifolia), which resisted the efforts of settlers. The Paraná pines are in private and public areas and are protected from logging. The Municipal Secretariat of the Environment maintains a botanical garden and three greenhouses that produce 150,000 native and exotic seedlings: 16,000 fruit trees, 260,000 flowers, foliage and underbrush specimens and the maintenance of another 350,000 seedlings.

Curitiba's green area itself matches the size of other large Brazilian cities. The vegetation of Curitiba encompasses a large population of purple and yellow ipês (tabebuias), who flower at the end of winter. The yellow ipê is one of the city's most common tree.

Hydrography

The catchment area of Curitiba consists of rivers and streams that cross the city in different directions, grouped in six river basins. The main rivers that form the city's watershed are: Atuba River, Belém River, Barigüi River, Passaúna River, Ribeirão dos Padilhas and the Iguaçu River, all with characteristics of dendritic drainage. Curitiba has been working since the 1970s on alternatives to minimize the negative impacts of urbanization on rivers. An example is the construction of parks along the rivers with artificial lakes, which absorb and retain water for longer periods of time, minimizing floods.
After many studies of local water flows, most rivers were found to be subject to a canalization process. Other alternatives developed to minimize the negative effects of urbanization are the implementation of programs for environmental education, inspection and monitoring, elaboration and application of legislation and infrastructure works.

Topography

The city covers  on the First Plateau of Paraná. Curitiba has a topography of smooth, rounded hills, giving it a relatively regular shape. The city has an average altitude of  above sea level. The highest point is to the north at , and with lower altitudes at  to the south.

Mountain ranges and sets of rocky hills surround parts of the city, including the Serra do Mar, a hill range between the shore of the Atlantic Ocean and the First Plateau in Paraná.

Government

, the mayor is Rafael Greca, who replaced Gustavo Fruet. The City Council of Curitiba has 38 councillors elected since 2004. Curitiba is divided into nine regional governments (equivalent to subprefecture), who manage the municipality's 75 districts. The Rua da Cidadania ("Street of Citizenship") is the symbol of administrative decentralization; it is a reference point and a meeting place. Several units are annexed to public transport terminals. Their nuclei offer services in the local, state and federal areas.

Jaime Lerner is perhaps Curitiba's best-known mayor. He was the mayor three times, the first time in the early 1970s. His leadership was crucial to some major changes in the city. Curitiba has built parks instead of canals to reduce flooding; used parks to make the city more liveable; pedestrianised the downtown area; built a Bus Rapid Transit (BRT), a bus system that works similarly to a light rail system; and started a massive recycling scheme that included giving people bus tokens in return for waste.

Demographics

Ethnic groups

According to the 2010 IBGE Census, 1,678,965 people resided in the city of Curitiba. The census revealed 1,381,938 White people (78.9%), 294,127 Pardo (Multiracial) people (16.8%), 49,978 Afro-Brazilian people (2.9%), 23,138 Asian people (1.4%), 2,693 Amerindian people (0.2%).

In 2010, Curitiba was Brazil's 8th most populous city.

In 2010, the city had 359,201 opposite-sex couples and 974 same-sex couples. The population of Curitiba was 52.3% female and 47.7% male.

As with most of Southern Brazil's population, Curitiba is mostly inhabited by European descendants. The first Europeans to arrive were of Portuguese origin, during the 17th century. They intermarried with the native people and with the African slaves.

Up until the 19th century, the inhabitants of the city of Curitiba were natives and mixed-race, Portuguese and Spanish immigrants. In 1808 foreigners were granted the right to ownership of land, and in 1853 Parana became an independent province, and these events resulted in a substantial number of immigrants from Europe.

The first non-Iberian (Portuguese and Spaniard) immigrants to come to the city were German.

The Memorial of Polish Immigration was inaugurated on 13 December 1980, after the visit of Pope John Paul II in June. Its area is  and was part of the former Candles plant. The seven wooden log houses are parts of this memorial area, as a memento of the Polish immigrants' struggles and faith. Objects like an old wagon, pipe of cabbage and a print of the Black Madonna of Częstochowa (patron saint of the Polish people), form parts of the memorial. The first group of Poles arrived in Curitiba around 1871. Curitiba has the biggest colony of Polish immigrants in Brazil.

Italian immigrants started arriving in Brazil in 1875 and in Curitiba in 1878, coming mainly from the Veneto and Trento regions of Northern Italy. They settled mostly in the Santa Felicidade neighborhood, still a centre of the Italian community.

Nearly 20,000 Ukrainian immigrants settled there between 1895 and 1897, consisting mostly of peasants from Galicia who immigrated to Brazil to become farmers. Around 300,000 Ukrainian-Brazilians live in Paraná. The State of Paraná has the largest Ukrainian community and Slavic community.

Curitiba has a Jewish community that was originally established in the 1870s. Much of the early Jewish congregation has been assimilated. In 1937 with the rise of Nazi Germany, notable German Jewish academics migrated to Brazil, some settling in Curitiba. Physicist César Lattes and former mayors Jaime Lerner and Saul Raiz were Jewish. A Holocaust memorial is present in the city. The community centre, a Jewish school, a Chabad house (Beit Chabad), a synagogue, and two Jewish cemeteries are there, one of which was defiled in 2004.

Japanese immigrants began arriving in 1915, with a larger contingent arriving in 1924. Curitiba received a significant Japanese influx. They settled mostly between Paraná and São Paulo state. The city has the second largest Japanese community in Brazil, behind only São Paulo, according to IBGE. Although both cities have around the same proportion of Japanese descendants, other large cities in the interior of the state of Paraná, such as Maringá and Londrina, have an even higher rate. Some estimates suggest that more than 40,000 Japanese-Brazilians live in Curitiba.

Religion

According to the 2010 Brazilian Census, most of the population (62.36%) is Roman Catholic, other religious groups include Protestants or evangelicals (24.03%), Spiritists (2.8%), Nones 6.71%, and people with other religions (3.69).

Economy

Since it was declared capital of the State of Paraná in 1853, the city has gone through several major urban planning projects to avoid uncontrolled growth and thus has become an international role model in dealing with issues including transportation and the environment. The city is Brazil's second largest car manufacturer. Its economy is based on industry, commerce and services. For that reason, Curitiba is considered by many investors to be the best location for investment in Brazil.

The city receives more than two million tourists every year. Most arrive via the Afonso Pena International Airport, where almost 60,000 flights land annually.

According to IPEA data, the GDP in 2006 was 32 billion reals, without including agriculture and livestock (0.03%). Industry represented 34.13% and the commerce and service sectors 65.84%. Cidade Industrial de Curitiba, the industrial district, is home to many multinational industries, such as Nissan, Renault, Volkswagen, Philip Morris, Audi, Volvo, HSBC, Siemens, ExxonMobil, Electrolux and Kraft Foods, as well as many well-known national industries, such as Sadia, O Boticário and Positivo Informática.

Curitiba's infrastructure makes bus travel fast and convenient, effectively creating demand for bus use in the same way that the infrastructure of traditional cities creates demand for private motor vehicles. In July 2001, Curitiba became Brazil's first city to receive the prize "Pole of Information Technology", granted by InfoExame magazine. According to the magazine, the companies of "Technology and Information Technology" based in Curitiba in 2001 achieved  in revenues, representing a growth of 21% over the previous year.

The city's 30-year economic growth rate is 7.1%, higher than the national average of 4.2%, and per capita income is 66% higher than the Brazilian average. Between 1975 and 1995, Curitiba's domestic product grew by some 75% more than the entire State of Paraná, and 48% more than Brazil as a whole. In 1994, tourism generated - 4% of the city's net income. Curitiba has municipal health, education and day care networks, neighborhood libraries shared by schools and citizens and Citizenship Streets, where buildings provide essential public services, sports and cultural facilities near transportation terminals. At the Open University, residents can take courses in subjects such as mechanics, hair styling and environmental protection for a small fee. Policies for job creation and income generation became part of the city's strategic planning in the 1990s, for the metropolitan area as well as the city.

Since 1990, the Municipal Housing Fund has provided financial support to housing for lower income populations. After national housing finance collapsed in 1985, just as people from the countryside poured into Curitiba, the city's public housing program bought one of the few remaining large plots of land, "Novo Bairro" (New Neighborhood), as home for 50,000 families. While landowners built the houses themselves, each received a pair of trees and an hour's consultation with an architect to help them develop their plan. COHAB also built Technology Street, an avenue of 24 homes in the centre of Novo Bairro, each built using different construction techniques.

Seven large shopping malls are found in Curitiba: Mueller, Estação, Curitiba, Crystal, Palladium, Patio Batel and Park Barigüi. The Rua das Flores (Street of Flowers) is home to the majority of stores. The area is pedestrianized, with no cars around the centre. An essential element of Curitiba shopping is the Feira do Largo da Ordem, or Largo da Ordem Street Fair.

In 2008, according to IBGE Curitiba's nominal GDP was  (or about of ) (with , or , by nominal GDP per capita, about of  more than Brazilian 2008 nominal GDP per capita), making it the fourth richest city in the country, after only São Paulo, Rio de Janeiro and the capital Brasília.

Curitiba is the second pole of technological innovation in Brazil, according to IPEA (Applied Economic Research Institute). It is Brazil's second best, and South America's fifth best, city for business, according to America Economia Magazine/2005 and 2006. The best destination for business, according to Veja Magazine of 2007. The third position among the Champions of Infrastructure, Exame Magazine of 2006. The second best city to work in Southern Brazil, according to Você S.A. Magazine of 2005. The 49th position, MasterCard Worldwide Centers of Commerce: Emerging Markets Index of 2008. One of the highlights according to the survey Offshoring Horizons performed by Watson Wyatt of 2007. One of the 10 global sustainability centres, according to Ethisphere Institute of 2008. Curitiba is also home to the largest cancer hospital in the South of Brazil, Erasto Gaertner Hospital.

Attractions

Attractions in the city include:

 Shrine of the Divine Mercy: established by the Marian Fathers near Estrada do Ganchinho in the district of Umbará.
Municipal market: Located near the city's central bus station, it houses numerous shops selling imported goods, organic products, and vegan food. The food court has a lot of Asian food, vegan food and organic meals.
 Italian Woods: Hosts local celebrations.
 Wire Opera House: Built on the site of an abandoned quarry.
 Oscar Niemeyer Museum: Artists from Paraná and other parts of Brazil have their work represented in the museum. Three rooms in the Eye are dedicated exclusively to photography.

 Panoramic Tower: The 360-foot tall lookout tower allows travelers a 360° view of Curitiba and has a telephone museum on the ground floor.
 Portugal Wood: Homage to the Portuguese-Brazilian bonds, this space is highlighted by a track following a small brook, where one can see drawn on tiles excerpts from famous Portuguese language poets, as well as a tribute to the great Portuguese navigators and their discoveries. Families are often seen picnicking on the grounds.
 Curitiba International Ecological Marathon: The Maratona Ecológica Internacional de Curitiba ("Curitiba International Ecological marathon") is held in November and is known as the hardest in Brazil, because it happens in the end of the year in the summer heat, and because of the hilly course.
 Tourism Line: The Linha Tourismo bus stops at key tourist attractions across the city.
Capão da Imbuia Wood

Education
More than 183 universities operate in the state of Paraná.

Tertiary educational institutions
 Universidade Federal do Paraná (UFPR) – Federal University of Paraná – This federal university is the largest of Paraná, with more than 35.000 students. The first university of Brazil;
 Universidade Tecnológica Federal do Paraná (UTFPR) – Federal Technologic University of Parana is the first university of technology from Brazil;
 Instituto Federal de Educação, Ciência e Tecnologia do Paraná – Paraná Federal Institute of Education, Science and Technology;
 Universidade Positivo (UP) – Positivo University, private institution;
 Universidade Estadual do Paraná (UNESPAR) – State University of Paraná, which includes EMBAP (Paraná School of Fine Arts) and FAP (College of Arts of Paraná);
 Pontifícia Universidade Católica do Paraná (PUCPR) – Pontifical Catholic University of Parana – A major private university;
 ESIC Business and Marketing School – International Website ESIC
 Centro Universitário Curitiba (UNICURITIBA) – University Center Curitiba, old Law School of Curitiba.
 Centro Universitário Internacional (UNINTER)
 Fundação de Estudos Sociais do Paraná (FESPPR) – The First Economy Graduation in Paraná, since 1938

Educational system
In the 1990s, the city started a project called Faróis do Saber ("Lighthouses of Knowledge"). These libraries are free educational centres that include libraries, free Internet access and other cultural resources. Libraries work with municipal schools, offering a collection of approximately 5000 books, and provide cultural reference and leisure.

Among Brazilian capitals, Curitiba has the highest literacy rate, and ranks number 1 in education among the Brazilian capitals.

Urban planning

Curitiba has a planned transportation system, which includes lanes on major streets devoted to a bus rapid transit system. The buses are split into three sections (bi-articulated) and stop at designated elevated tubes, complete with access for disabled riders. Buses charge one price regardless of distance.

The city preserves and cares for its green areas, boasting  of green space per inhabitant.

In the 1940s and 1950s, Alfred Agache, cofounder of the French Society for Urban Studies, was hired to produce the first city plan. It emphasised a star of boulevards, with public amenities downtown, an industrial district and sanitation. The plan was too expensive to complete.

By the 1960s, Curitiba's population had reached 430,000. Some residents feared that the growth in population threatened to damage the character of the city. In 1964, Mayor Ivo Arzua solicited proposals for urban design. Architect Jaime Lerner, who later became mayor, led a team from the Universidade Federal do Paraná that suggested strict controls on urban sprawl, reduced traffic in the downtown area, preservation of Curitiba's Historic Sector and a convenient and affordable public transit system.

This plan, known as the Curitiba Master Plan, was adopted in 1968. Lerner closed XV de Novembro St. to vehicles, because it had high pedestrian traffic. The plan had a new road design to minimise traffic: the Trinary Road System. This used two one-way streets moving in opposite directions that surround a smaller, two-lane street where the express buses have an exclusive lane. Five of these roads form a star that converges on the city centre. Land farther from these roads is zoned for lower density development, to pull traffic away from the main roads. In a number of areas subject to floods, buildings were condemned and the land became parks.

Today, Curitiba is considered one of the world's best examples of urban planning. In June 1996, the chairman of the Habitat II summit of mayors and urban planners in Istanbul praised Curitiba as "the most innovative city in the country".

Curitiba was recently recommended by UNESCO as a model for the reconstruction of the cities of Afghanistan. In the 1980s, the RIT (Rede Integrada de Transporte, Integrated Transport Network) was created. At the same time, the city began building the "Faróis de Saber" (Lighthouses of Knowledge) educational centres. The city has more than  of public parks and forests.

In 2007, the city placed third in a list of "15 Green Cities" in the world, according to Grist magazine, after Reykjavík in Iceland and Portland, Oregon in the United States. As a result, according to one survey, 99% of Curitibans are happy with their hometown.

Jaime Lerner suggests urban acupuncture as the future solution for contemporary urban issues; focusing on very narrow pressure points in cities, can create positive ripple effects. Urban "acupuncture" reclaims land for the public and emphasizes the importance of community development through small interventions in design of cities. It emphasises pinpoint interventions that can be accomplished quickly to create an immediate impact.

The "capacity building job line" was created to accelerate economic development. About 15,000 new jobs were generated by 2013.

According to Jonas Rabinovitch, a United Nations senior adviser and former planner at the Curitiba Research and Urban Planning Institute (IPPUC), up to 8% of Curitiba's population still lived in favelas as of 2016. According to 2010 census data collected by IBGE, 49,700 homes in Curitiba form part of irregular settlements. This is equivalent to 163,300 people. The population growth of favelas was 12.4% between 2000 and 2010, higher than the population in general (10.3%).

For transportation, Curitiba has over 2 million people travel by bus while the city also has the most cars per capita in Brazil.

Culture

In January 1973 the Fundação Cultural de Curitiba was set up, with the aim of promoting culture.

The Cultural Complex Solar do Barão features the Photography Museum, the Engravings Museum and the Posters Museu. The MuMA – Museu Metropolitano de Arte (Museum of Metropolitan Art) displays artists from the state of Paraná as well as renowned Brazilian painters such as Pancetti, Guignard and Di Cavalcanti.

The Polish Immigrants Memorial, also known as The Pope's Woods, offers an enjoyable area surrounded by trees, which makes it a perfect choice for a stroll. The Polish Pope John Paul II blessed the first replica of the traditional Polish houses that beautifully make up the Bosque do Papa when he visited the city in 1980.

In 2003, Curitiba received the "American Capital of Culture" title, granted by the OAS (Organization of American States).

Gastronomy
The capital of Paraná is an important gastronomic center in Brazil, and the typical foods of Curitiba tend be very different when compared to other common Brazilian dishes. The dishes of the local cuisine are a reflection of the history of the municipality and the typical foods. Curitiba's cuisine has mainly been influenced by Italian and German immigrants.

Curitiba is the home of the largest restaurant in the Americas, and one of the world's largest restaurants, Restaurante Madalosso. Madalosso can feed more than 4,600 diners at a time in its 10 dining rooms, all named after Italian cities. Founded in 1963, the all-you-can-eat Madalosso focuses on family-style Italian cuisine: ravioli, lasagna, gnocchi, and salads rounded out with grilled meats.

Arts and entertainment
Curitiba was Brazil's first city to have an IMAX movie theatre. Curitiba has many theaters. The largest and most important one is the Guaíra Theater. Every year, in April, it hosts the Curitiba Theater Festival.

Museums
Brazilian architect Oscar Niemeyer designed the extravagant state museum of Curitiba. Its design includes a gravity-defying construction that was intended to look like a Paraná Pine, one of the city's symbols, but is widely interpreted by locals as an eye, which gave the Museum its nickname – Museu do Olho, or Museum of the Eye. In keeping with Curitiba's history and culture of science, the museum offers many science exhibitions, including biennial exhibitions. The Curitiba museum includes the Oscar Niemeyer auditorium.

 Museu Paranaense ("Paranaense Museum") – dedicated to arts and history;
 Oscar Niemeyer Museum – the largest museum of South America, dedicated to plastic arts;
 Museu de Arte Sacra ("Religious Art Museum") – the focus is Christian art;
 Museu do Expedicionário ("Museum of the Expeditionary") – dedicated to Brazilian participation in World War II;
 Museu de Arte Contemporânea ("Museum of Contemporary Art");
 Museu da Imagem e do Som ("Image and Sound Museum") – about cinema and photography;
 Museu Egípcio e Rosa Cruz ("Egyptian Museum and Rosicrucianism") - ancient Egypt antiquities
 Museu Metropolitano de Arte de Curitiba ("Metropolitan Museum of Art in Curitiba") – modern art;
 Museu de História Natural ("Natural History Museum") – biology and botany.
 Museu do Holocausto ("Holocaust Museum")

Festivals
Curitiba has yearly festivals related to arts, such as Curitiba Theatre Festival and the Music Workshop of Curitiba. Others celebrate immigrants festivals, such as the Grape Feast ("Festa da Uva"), which is related to Italian immigrants, and the four Matsuri, related to Japanese immigrants.

The four Matsuri set in Curitiba are: Imin Matsuri (Japanese: 移民祭り, "Immigration Festival") which celebrates the arrival of Japanese immigrants in Brazil, Haru Matsuri (Japanese: 春祭り, "Spring Festival") which celebrates the end of winter and coming of spring, Hana Matsuri (Japanese: 花祭り, "Flower Festival"), which celebrates the birth of Sakyamuni, and Seto Matsuri ("Seto Festival"), in honor of Cláudio Seto, comic artist, precursor of the manga in Brazil and idealist of the first Matsuri in Curitiba.

Curitiba also hold the famous Psycho Carnival, a three-day festival that happens during the Brazilian Carnival, but devoted to psychobilly and rockabilly genres, attracting people from all over the world. In the same occasion the Zombie Walk also happens. The 2016 edition took more than 20,000 people to the streets.

UN Convention on Biodiversity
On 20–31 March 2006 the Convention on biodiversity took place in Pinhais (a city near Curitiba), addressing items of the 1993 Convention on Biological Diversity adopted by 188 countries.

Transportation

Public transport

Curitiba's public transportation consists entirely of buses. It opened the world's second bus rapid transit (BRT) system, Rede Integrada de Transporte, in 1974. The popularity of Curitiba's BRT has effected a modal shift from automobile travel to bus travel. Based on 1991 traveler survey results, it was estimated that the introduction of the BRT had caused a reduction of about 27 million auto trips per year, annually saving about 27 million liters of fuel. In particular, 28 percent of BRT riders previously traveled by car. Compared to eight other Brazilian cities of its size, Curitiba uses about 30 percent less fuel per capita, resulting in one of the country's lowest rates of ambient air pollution. Some 1,100 buses make 12,500 trips every day, serving more than 1.3 million passengers, 50 times the number from 20 years ago. Eighty percent of travelers use the express or direct bus services. Curitibanos spend only about 10 percent of their income on transportation, far below the national average.

Curitiba has in its transport fleet the largest bi-articulated bus in the world, with 28 meters in length and capacity for 250 passengers. The bus operates only with soy-based biofuel, which reduces pollutant emissions by 50%.

The city government has been planning to introduce an underground metro for a number of years and in 2014 announced opened tenders for a 35-year public private partnership contract to build and operate a , 14-station north–south line. The cost is estimated at 4.62 billion reais.

Roads
Moving around in a car can be difficult in and around the city centre because of the many one-way streets and frequent traffic jams. The Trinary Road System allows quick access to the city centre for drivers. Some avenues are spacious and laid out in a grid. Apart from some points around the city centre, Munhoz da Rocha Street and Batel Avenue, traffic jams are not severe.

Air

Afonso Pena International Airport is Curitiba's main airport. It is located in the nearby city of São José dos Pinhais. All commercial flights operate from this airport. It was evaluated as the best airport in Brazil according to the Ministry of Infrastructure of Brazil.

The airport obtained the highest marks among all participants for queuing time at customs and the cordiality of customs officials; availability of sockets and seats in the departure lounge; quality of airport signage and vehicle parking facilities; availability and cleanliness of the toilets; general cleaning; airport thermal and acoustic comfort; quality of information on baggage claim conveyor panels, as well as availability of public transport to the airport.

There is also the Bacacheri Airport, a smaller general aviation facility. It serves the handling of small and medium business aircraft.

Rail
Brazil's transportation and railway company, Rumo, has its headquarters in Curitiba. Serra Verde Express provides a tourist train through scenic country to Morretes and Paranaguá.

Others
The city has  of bike routes, used by around 30 thousand bikers daily. City streets carry almost one million vehicles, of which 2,253 are orange Taxis. To service these vehicles, more than 355 petrol stations serve the city.

Curitiba public transportation statistics
The average amount of time people spend commuting with public transit in Curitiba, for example to and from work, on a weekday is 72 min. 21% of public transit riders, ride for more than 2 hours every day. The average amount of time people wait at a stop or station for public transit is 17 min, while 33% of riders wait for over 20 minutes on average every day. The average distance people usually ride in a single trip with public transit is 7 km, while 12% travel for over 12 km in a single direction.

Sports

Curitiba has three teams in the city: Athletico Paranaense, Coritiba and Paraná Clube. Paraná Clube plays at Estádio Durival Britto e Silva, Coritiba plays at Estádio Major Antônio Couto Pereira, and Club Athletico Paranaense plays at Estádio Joaquim Américo Guimarães. Both Coritiba and Athletico Paranaense have won Campeonato Brasileiro Série A, in 1985 and 2001, respectively. Estádio Joaquim Américo Guimarães was one of the 12 stadiums to host games of the 2014 FIFA World Cup held in Brazil. The traditional stadium Vila Capanema have hosted the 1950 FIFA World Cup which still is home to Paraná Clube.

The Autódromo Internacional de Curitiba (Curitiba International Raceway) is located in nearby Pinhais.

Curitiba has also one of the main rugby union clubs in Brazil, Curitiba Rugby Clube, national champions in 2014.

A number of top stars in mixed martial arts are Curitiba natives, including the Rua brothers Maurício "Shogun" and Murilo "Ninja", Wanderlei Silva, Anderson Silva, and women's MMA pioneer Cris Cyborg. Much of the city's success in MMA comes from it hosting the influential Chute Boxe Academy and its successor Universidade da luta.

Neighborhoods

Most districts of Curitiba were born of colonial groups, formed by families of European immigrants in the second half of the nineteenth century. The centro (downtown or central business district), where the city was founded, is the most bustling area, housing most of the financial institutions of Curitiba.

Bairros (neighborhoods) of Curitiba define the city's geographical divisions. Administrative powers are not delegated to neighborhoods, although neighborhood associations work to improve their communities.
Curitiba is divided into 9 regional governments (boroughs) covering the 75 neighborhoods.

Civic Center (In Portuguese: Centro Cívico) is where the main government buildings are located. It was the first neighborhood in the municipality of Curitiba, capital of the state of Paraná. The name means 'Center of the Citizen''. It was conceived in 1953, with the greater independence which came with the creation of a new state.

In August 2011, the Civic Center was listed as an urban and architectural ensemble. The buildings on the central axis of Avenida Cândido de Abreu are protected, including Plaza 19 de Dezembro, Tiradentes State College, Courts of Justice, Accounts and Jury buildings, the Iguaçu Palace, the Oscar Niemeyer Museum and the Square Our Lady of Salette.

International relations

Twin towns – sister cities
Curitiba is twinned with:

 Asunción, Paraguay
 Coimbra, Portugal
 Columbus, United States
 Guadalajara, Mexico
 Hangzhou, China
 Himeji, Japan
 Jacksonville, United States
 Kraków, Poland
 Lyon, France
 Montevideo, Uruguay
 Orlando, United States
 Santa Cruz de la Sierra, Bolivia
 Suwon, South Korea
 Treviso, Italy
 Miami-Dade, United States

Cooperation agreements
Curitiba has cooperation agreements with:
 Lisbon, Portugal

People

Aviation
 Pierre Clostermann – World War II French pilot, engineer
 Egon Albrecht – World War II German flying ace

Politics
 Sérgio Moro – Politician

Science
 Newton da Costa – mathematician
 José Hauer - electrical engineer
 Alex Kipman – scientist
 Ned Kock – systems scientist
 César Lattes – physicist
 Ricardo Ramina – physician

Sports
 Chess
 Jaime Sunye Neto, chess Grandmaster

 Football

 Mixed martial arts
 Cristiane "Cyborg" Justino
 Bruno Pucci
 Mauricio "Shogun" Rua
 Murilo "Ninja" Rua
 Wanderlei Silva
 Anderson Silva

 Motorsports
 Enrique Bernoldi – Formula One driver – IndyCar driver
 Raul Boesel – Formula One driver, IndyCar driver, 1987 World Sportscar Championship champion
 Marco Campos – racing driver
 Pietro Fantin – racing driver
 Augusto Farfus – DTM driver for BMW
 Lico Kaesemodel – racing driver
 Tarso Marques  – Formula One driver
 Diego Nunes – racing driver
 Sérgio Paese – racing driver
 Edson Reis – racing driver
 Nilton Rossoni – racing driver
 Leonardo de Souza – racing driver
 Ricardo Zonta – Formula One driver, 1998 FIA GT Championship champion

 Basketball
 Rolando Ferreira – (Gold medalist at the 1987 Pan American Games), former Portland Trail Blazers player

 Beach volleyball
 Emanuel Rego (gold medalist in 2004 Olympics, bronze in 2008 Olympics and silver in 2012 Olympics)
 Agatha Bednarczuk (silver medalist in 2016 Olympics)

 Horse racing
 João Moreira – jockey

 Poker
 Alexandre Gomes (WSOP and WPT world champion 2008–2009)

 Skateboarding
 Gui Khury

 Swimming
 Henrique Rodrigues
 Fernanda de Goeij

Architecture

 Jaime Lerner
 João Batista Vilanova Artigas

Arts

 Abraskadabra - Ska punk band
 Alfredo Andersen – Norwegian painter and sculptor
 Alexandre Slaviero – actor
 Andrade Muricy – composer and musical and literary critic
 Dalton Trevisan – writer
 Dinho Ouro Preto – rock musician
 Emílio de Meneses – poet and journalist, "immortal" of the Brazilian Academy of Letters
 Fernanda Machado – actress
 Florian Essenfelder – piano maker
 Francisco Lachowski – super model
 Guido Viaro – Italian painter and teacher
 Guilherme Weber – actor
 Guta Stresser – actress
 Icarius De Menezes – creative director
 Isabeli Fontana – super model
 Isadora Ribeiro – actress
 Ary Fontoura – brazilian actor, writer and blogger
 Ewandro Stenzowski – operatic tenor
 Katiuscia Canoro – actress
 Luís Melo – actor
 Luiz Carlos Alborghetti – TV host
 Marjorie Estiano – actress and singer
 Henrique de Curitiba – composer
 Marcelo Madureira – brazilian comedian, part of the Casseta & Planeta.
 Simone Spoladore – actress
 Tasso da Silveira – poet, journalist, deputy and professor

See also
History of Paraná
Luxembourgish Brazilians

References

Bibliography

External links

 Official homepage

Planned communities in Brazil
Populated places established in 1693
1693 establishments in the Portuguese Empire
State capitals in Brazil

Curitiba


Tax advantage refers to the financial gain which applies to certain accounts or investments. These include accounts that are, by statute, tax-reduced, tax-deferred, or tax-free. Governments establish tax advantages to encourage private individuals to contribute money when it is considered to be in the public interest. An example is retirement plans, which often offer tax advantages to incentivize savings for retirement. In the United States municipal bonds may also be exempt from certain taxes.

In countries in which the average age of the population is increasing, tax advantages may put pressure on pension plans. For example, where benefits are funded on a pay-as-you-go basis, the benefits paid to those receiving a pension come directly from the contributions (money paid) of those of working age. If the proportion of pensioners to working-age people rises, the contributions needed from working people will also rise proportionately. In the United States, the rapid onset of Baby Boomer retirement is currently causing such a problem.

References

Taxation

Tax advantage


Russian roulette is a deadly game played with a revolver. In the game, there is only one bullet in one of the six cylinder slots of the revolver. The person then closes the cylinder, spins it, places it against their head or sometimes inside their mouth and pulls the trigger, in hopes that the loaded cylinder slot hasn't aligned with the barrel and will therefore fire. The person therefore has a one-in-six chance of killing themselves.

It is done either for bravado, boredom, suicide or other reasons. It sometimes used in fiction as part of interrogations, where the interrogator asks the suspect if he wants to play a game of Russian roulette and palms the bullet.

Related pages
 Roulette

Games

Russian roulette


Cazimierz Funk, also known as Kasimir Funk, was a Polish-American biochemist. He proposed the idea of vitamins in 1912, which he initially called "vital amines" or "vitamines."

Achievements
After reading an article by a Dutchman named Christiaan Eijkman, which said that people who ate brown rice were less likely to get beri-beri compared to those who only ate fully milled rice, a scientist named Funk tried to find the specific substance responsible for this. He was successful and named it "vitamine" because it contained an amine group. It was later called vitamin B3 (niacin), even though he initially thought it would be vitamin B1 (thiamine) and described it as the "anti-beri-beri-factor.

In 1912, he suggested the existence of at least four vitamins: one to prevent beriberi, one for scurvy, one for pellagra, and one for rickets. He later published a book called "The Vitamines" in 1912 and received a research fellowship.

Funk also suggested that other diseases like rickets, pellagra, coeliac disease, and scurvy could also be treated with vitamins. He was one of the early researchers to investigate pellagra, attributing it to changes in the corn milling process, although his findings were largely ignored.

The "e" in "vitamine" was removed when it was realized that vitamins don't have to be nitrogen-containing amines.

He suggested there are other essential nutrients, which we now call vitamins B1, B2, C, and D.

In 1936, he figured out the structure of thiamine, but he wasn't the first to isolate it.

Funk also studied hormones, diabetes, peptic ulcers, and cancer biochemistry.

After coming back to the United States, he became the president of the Funk Foundation for Medical Research in 1940. In his later years, he focused on understanding the causes of cancers.

Funk Award
The Polish Institute of Arts and Sciences of America (PIASA) gives an award called the Casimir Funk Natural Sciences Award each year to outstanding Polish-American scientists. Previous winners of this award have included notable individuals like Nobel Laureate Roald Hoffmann, Aleksander Wolszczan, Hilary Koprowski, Peter T. Wolczanski, Wacław Szybalski, Zbyszek Darzynkiewicz, and Benoit Mandelbrot.

Casimir Funk