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2. Factors affecting photobiological hydrogen production in five filamentous cyanobacteria from Thailand

Creator:
Yodsang, P., Raksajit, W., Aro, E.-M., Mäenpää, P., and Incharoensakdi, A.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
sinice, vodík, Cyanophyta, hydrogen, Thajsko, Thailand, heterocyst, culturing parameters, N2-fixing condition, 2, and 581
Language:
Multiple languages
Description:
We report here the screening of sixteen cyanobacterial and three green algal strains from Thailand for their potential biohydrogen production. Five filamentous cyanobacterial species, namely Calothrix elenkinii, Fischerella muscicola, Nostoc calcicola, Scytonema bohneri, and Tolypothrix distorta, all possessing nitrogenase activity, showed potentially high biohydrogen production. These five strains showed higher hydrogen production in the absence than in the presence of nitrogen. In particular, F. muscicola had a 17-fold increased hydrogen production under combined nitrogen and sulfur deprived conditions. Among various sugars as a carbon source, glucose at 0.1% (w/v) gave the maximal hydrogen production of 10.9 μmol(H2) mg-1(Chl) h-1 in T. distorta grown in BG11 medium without nitrate. Increasing light intensity up to 250 μmol(photon) m-2 s-1 increased hydrogen production in F. muscicola and T. distorta. Overall results indicate that both F. muscicola and T. distorta have a high potential for hydrogen production amenable for further improvement by using molecular genetics technique., P. Yodsang, W. Raksajit, E.-M. Aro, P. Mäenpää, A. Incharoensakdi., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Hydrogen production by two-stage co-pyrolysis of bituminous coal-polymers mixtures

Creator:
Pavel Straka and Kříž, Vlastimil
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, uhlí, polymery, vodík, coal, polymers, hydrogen, co-pyrolysis, 7, and 551
Language:
English
Description:
The two stage co-pyrolysis method for obtaining of hydrogen is described. In the course of the heating of the mixture of bituminous coal with polyisoprene and styrene-butadiene polymers (co-pyrolysis), a considerable amount of hydrogen and hydrocarbons is released in dependence on the process conditions. The experiments proved that the amount of hydrogen increased already with slightly increased heating rate (5 K min-1 ) in comparison with the amount obtained at a common heating rate (3 K min-1) and, further, with the addition of the second (cracking) stage for further thermal splitting of release d hydrocarbons into hydrogen (and carbon), preferably at a temperature of 1200 ºC., Pavel Straka and Vlastimil Kříž., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. Jak byla vynalezena vodíková bomba

Creator:
Hnatowicz, Vladimír
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
Bethe, Hans Albrecht, 1906-2005, Fuchs, Klaus, 1911-1988, Garwin, Richard, Kurčatov, Igor' Vasil'jevič, 1902-1960, von Neumann, John, 1903-1957, Oppenheimer, J. Robert, 1904-1967, Sacharov, Andrej Dmitrijevič, 1921-1989, Tamm, Igor' Jevgen'jevič, 1895-1971, Teller, Edward, 1908-2003, Ulam, Stanislaw M., 1909-1984, Zel'dovič, Jakov Borisovič, 1914-1987, 20. století, jaderná fyzika, termojaderná syntéza, atomová bomba, vodík, nuclear physics, thermonuclear fusion, atomic bomb, hydrogen, 6, and 53
Language:
Czech
Description:
Článek popisuje vývoj vodíkové bomby a historické pozadí, na kterém se odehrál. Pozornost je věnována zejména vzniku a vývoji fyzikálních idejí, které vedly k objevu základního principu konstrukce vodíkové bomby v USA a SSSR. Rovněž je zmíněna úloha jednotlivých význačných věců, kteří se na tomto vývoji podstatnou měrou podíleli. Autor považuje historii vývoje vodíkové bomby za zajímavou nejen z čistě fyzikálně-technického hlediska, ale i pro komplikovaný vztah mezi zaujetím vědeckým problémem a morálními principy., Vladimír Hnatowicz., Obsahuje 11 medailonků vědeckých osobností, and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

5. Konstrukce a aplikace disociačního termálního zdroje svazků atomů vodíku

Creator:
Mach, Jindřich, Potoček, Michal, Kolíbal, Miroslav, and Šikola, Tomáš
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
hydrogen, thermal dissociation, atom source, atomic hydrogen beam, vodík, disociace, termální atomární zdroj, and svazek atomů vodík
Language:
Czech
Description:
The design and construction of a thermal dissociation source for generation of hydrogen atomic beams with thermal energy (0.1 - 1 eV) will be described. The main application areas of presented source covers: low-temperature cleaning of surfaces and ultrathin films, preparation of hydrogen passivated surfaces, and hydrogen assisted molecular beam epitaxy. The hydrogen molecules were dissociated in a tungsten capillary heated by electron bombardment. The properties (profile, dissociate) of these atomic source were measured by a quadrupole mass spectrometer in the differentially pumped chamber., Článek popisuje návrh a konstrukci termálního disociačního zdroje poskytujícího svazky atomů vodíku o termální energii (0,1 - 1 eV). Zdroj pracuje v UHV podmínkách a je primárně určen k následujícím aplikacím: nízkoteplotní čištění povrchu a ultratenkých vrstev, příprava vodíkem pasivovaných povrchů a molekulární svazková epitaxe s asistencí vodíkových atomů. Molekuly vodíku byly disociovány na vnitřním povrchu wolframové kapiláry, která byla žhavena dopadem urychlených elektronů. Vlastnosti tohoto zdroje byly studovány užitím kvadrupólového hmotnostního spektrometru umístěného v diferenciálně čerpané UHV komoře., and obrázky 2, 3, 4, 5, 6 a 7 jsou uvedeny na 2. straně obálky v barevném provedení
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

6. Oxygenic photosynthesis - a photon driven hydrogen generator - the energetic/entropic basis of life

Creator:
Hoffmann, P.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
evolution, hydrogen, life, photosynthesis, and radiant energy
Language:
Multiple languages
Description:
Photosynthesis, as a fundamental element in the life process, is integrated in the evolution of living systems on the basis of hydrogen cycles on various hierarchic levels. Conversion of radiant energy enables the oxidation of water, whereby free oxygen accumulates in the atmosphere. Hydrogen is (reversibly) stored in organic materials formed under reductive CO2-fixation and by the incorporation of the other elements, which are necessary for living systems. All endergonic processes in living cells are finally driven by the energy released through the clean recombination of protons and electrons with oxygen to water. Duration of the stored energy and the complexity of the systems thus produced is correlated negatively with the conversion efficiency of the radiation energy. Entropy is a unifying principle in the evolution of living systems, inclusive human societies.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

7. The resources and methods of hydrogen production

Creator:
Olga Bičáková and Straka, Pavel
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, vodík, pyrolýza, kopyrol, hydrogen, pyrolysis, conventional methods, co-pyrolysis, thermochemical cycles, electrolysis, 7, and 551
Language:
English
Description:
In the near future, hydrogen will become an important fuel which may be able to resolve local problems connected with air quality. Hydrogen-propelled transport means are being developed and are already used in the automobile industry. Since the combustion of hydrogen does not produce any emissions of carbon oxides but only water, hydrogen is considered as a key fuel of the future. Hydrogen is abundantly present all over space and can be obtained from a number of resources, be they renewable or non-renewable. Global production has so far been dominated by hydrogen production from fossil fuels, with the most significant contemporary technologies being the reforming of hydrocarbons, pyrolysis and co-pyrolysis. Plasma cracking is still in the developmental stage. The preferred method of hydrogen production on an industrial scale is steam reforming of natural gas for its low operational and production costs. When the operational costs of steam reforming and partial oxidation are compared, partial oxidation seems to be a more acceptable process, but the subsequent shift makes this process more expensive. Pyrolysis processes have acceptable investment costs and besides the production of hydrogen also satisfactory yields of oils. Two-stage co-pyrolysis is suitable considering its acquisition of a high amount of hydrogen from mixed charges. It is apparent that the co-pyrolysis of organic materials with coals is a process for hydrogen production capable of competing. It can therefore play a significant role in the future., Olga Bičáková and Pavel Straka., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public