Proton–proton chain reaction

The proton–proton chain reaction is one of two nuclear fusion reactions, along with the CNO cycle, by which stars convert hydrogen to helium and which dominates in stars the size of the Sun or smaller.

In general, proton–proton fusion can occur only if the kinetic energy (i.e. temperature) of the protons is high enough to overcome their mutual electrostatic or Coulomb repulsion.

In the Sun, deuterium-producing events are rare as diprotons, the much more common result of nuclear reactions within the star, immediately decay back into two protons. A complete conversion of the hydrogen in the solar core is calculated to take more than 7010100000000000000♠10¹⁰ (ten billion) years.

History of the theory

The theory that proton–proton reactions are the basic principle by which the Sun and other stars burn was advocated by Arthur Stanley Eddington in the 1920s. At the time, the temperature of the Sun was considered too low to overcome the Coulomb barrier. After the development of quantum mechanics, it was discovered that tunneling of the wavefunctions of the protons through the repulsive barrier allows for fusion at a lower temperature than the classical prediction.

Stal Rzeszów

Stal Rzeszów is a Polish football and speedway club based in Rzeszów, Poland.

History

The history of Stal Rzeszow dates back to November 1944, when a group of sports enthusiasts, working at WSK PZL Rzeszow (Transport Equipment Enterprise) decided to form a Sports Circle. With support of the Youth Organization of the Association of Workers University (Organizacja Mlodziezy Towarzystwa Uniwersytetu Robotniczego, OM TUR), the new club was managed by Bronislaw Szczoczarz.

In March 1945, football team of PZL OM TUR was formed, under manager Jan Polak. In its first game, OM TUR faced Szturmowiec (Walter) Rzeszow, the match ended in a 2-2 draw. By the summer of 1945, OM TUR played several friendly games, facing Sokol Rzeszow (4-6), Czuwaj Lancut (2-6), and in June 1945, it played in the City of Rzeszow Cup tournament, losing in the final 1-3 to Resovia.

In the autumn of 1946, a series of playoffs took place, in order to find best teams for the newly created Rzeszow A-Class. PZL OM TUR managed to qualify to the league, together with such teams, as Legia Krosno, Nafta Krosno, Orzel Gorlice, Sanoczanka, Cukrownia Przeworsk, Resovia, Sokol Rzeszów, Czuwaj Przemysl and Polonia Przemysl. By 1955, however, the team did not have its own field, and had to use the fields of other clubs. On June 26, 1955, first game took place at the newly built PZL Rzeszow stadium, at Hetmanska Street. The reserve team of Poland B faced Bulgarian reserves (1-1). In the second game of the day, Stal Rzeszow, the host, tied 1-1 with Poland U-19 team.

KSZO Ostrowiec Świętokrzyski

KSZO Ostrowiec Świętokrzyski (Polish pronunciation: [ˈkʂɔ ɔsˈtrɔvʲɛt͡s ɕfʲɛntɔˈkʂɨskʲi]) is a Polish football club based in Ostrowiec Świętokrzyski, Poland. It was founded on August 11, 1929.

History

In 1995, after several decades in lower league football, mainly the third division, KSZO for the first time promoted to the second division of the Polish football league. After just two years, in 1997, the club advanced to the Polish top level football league, Ekstraklasa. However the first season in Ekstraklasa end up with relegation. KSZO once again promoted to Ekstraklasa in 2001. 13th place finish was the result of quite well performance in 2001/2002 season.

The next season started very promisingly, however, financial problems led to the relegation. The problems were more and more severe and by the end of 2003 KSZO was liquidated and recreated on the basis of another 2nd league club KS Stasiak Ceramika Opoczno. Since then the club performed as KSZO sports p.l.c. in the 2nd league.

Warta Poznań

Warta Poznań (Polish pronunciation: [ˈvarta ˈpɔznaɲ]) is a multi-sports club based in Poznań, Poland.

Founded in 1912, the association football section are two-time winners of the Polish Football Championship, in 1929 and 1947, but currently reside in the Polish Second League. The name means the Guard in Polish and also a name of river Warta on which Poznań is located. The club also played in second level between 1951–1952 (2 seasons), 1956–1960 (5 seasons), 1970–1971, 1973–1975, 1977–1979, 1991–1993, 1995–1996, 1997–1998 and since 2007. They played in the top level last between 1993–1995.

The club has also one of the most successful field hockey and tennis teams in the country.

Honours