Téli sózásnak kitett, gőzölt vesbeton szerkezet tartósságának elvi kérdései

1. Kísérletileg igazoltuk, hogy a C3A és C4AF klinkerásványok kloridion megkötő képességét a gőzölés javítja. A kloridion megkötő képesség növekedése a gőzölés hatására C3A klinkerásvány esetén nagyobb, mint a C4AF klinkerásvány esetén. 2. Kísérletileg igazoltuk, hogy a gőzölt cementpépek (betonok) több kloridiont kötnek meg Friedel-só formájában, mint a gőzöletlenek. Továbbá a 90C-on gőzölt cementpép minták több kloridiont kötöttek meg, mint a 60C-on gőzölt cementpép minták. 3. A cementek kloridion megkötő képessége eltérő. A vizsgált cementek kloridion megkötő képessége (mind természetes szilárdulás, mind gőzölés esetén) csökkenő sorrendben a következő: - CEM III/A 32,5 (40m% kohósalaktartalmú heterogén porlandcement) - CEM I 42,5 (tiszta portlandcement) - CEM I 32,5 RS (szulfátálló tiszta portlandcement). E cementek közül a legtöbb kloridiont a CEM III/A 32,5 jelű cement köti meg, ami egyértelműen azt bizonyítja, hogy nemcsak a C3A-nak és a C4AF-nek van kloridion megkötő képessége, hanem az őrölt granulált kohósalaknak is. A legkevesebb kloridiont a CEM I 32,5 RS jelű cement köti meg. | 1. Our experimental results indicated that the chloride ion binding capacities of C3A and C4AF cement clinkers are improved if they were subjected to steam curing. 2. Our experimental results indicated that more chloride ions are bound in cements (as well a sin concretes) in form of Friedel-salt if they were subjected to steam curing. Furthermore, more chloride ions are bound in cements after steam curing at 90C compared to those at 60C. 3. Chloride ion binding of various cements is different. Our test results provided the following list of investigated cements with decreasing capacities of chloride ion binding (both for cements with natural hardening and with steam curing): - CEM III/A 32.5 (Portland cement with 40 m% blast furnace slag) - CEM I 42.5 (Portland cement) - CEM I 32.5 (sulphate resistant Portland cement). Among these cements the highest amount of chloride ions are bound by CEM III/A 32.5 which is an evidence that not only C3A and C4AF cement clinkers are able to bind chloride ions but also the granulated blast furnace slag. The least amount of bound chloride ions was obtained by CEM I 32.5 RS

Anisotropy of the sky distribution of gamma-ray bursts

The isotropy of gamma-ray bursts collected in current BATSE catalog is studied. It is shown that the quadrupole term being proportional to \sim sin 2b sin l is non-zero with a probability of 99.9%. The occurrence of this anisotropy term is then confirmed by the binomial test even with the probability of 99.97 %. Hence, the sky distribution of all known gamma-ray bursts is anisotropic. It is also argued that this anisotropy cannot be caused exclusively by instrumental effects due to the nonuniform sky exposure of BATSE instrument. Separating the GRBs into short and long subclasses, it is shown that the short ones are distributed anisotropically, but the long ones seem to be distributed still isotropically. The character of anisotropy suggests that the cosmological origin of short GRBs further holds, and there is no evidence for their Galactical origin

Turning gold into 'junk': transposable elements utilize central proteins of cellular networks

The numerous discovered cases of domesticated transposable element (TE) proteins led to the recognition that TEs are a significant source of evolutionary innovation. However, much less is known about the reverse process, whether and to what degree the evolution of TEs is influenced by the genome of their hosts. We addressed this issue by searching for cases of incorporation of host genes into the sequence of TEs and examined the systems-level properties of these genes using the Saccharomyces cerevisiae and Drosophila melanogaster genomes. We identified 51 cases where the evolutionary scenario was the incorporation of a host gene fragment into a TE consensus sequence, and we show that both the yeast and fly homologues of the incorporated protein sequences have central positions in the cellular networks. An analysis of selective pressure (Ka/Ks ratio) detected significant selection in 37% of the cases. Recent research on retrovirus-host interactions shows that virus proteins preferentially target hubs of the host interaction networks enabling them to take over the host cell using only a few proteins. We propose that TEs face a similar evolutionary pressure to evolve proteins with high interacting capacities and take some of the necessary protein domains directly from their hosts