ARACHNOLOGICAL EVIDENCE FOR GLACIAL REFUGIA IN THE BAVARIAN ALPS
MUSTER C.: Arachnological evidence for glacial refugia in the Bavarian Alps. In GAJDOS P., PEKAR S. (eds): Proceedings of the 18th European Colloquium of Arachnology, Stara Lesna, 1999. Ekologia (Bratislava), Vol. 19, Supplement 3/2000, p. 181-192. According to geomorphological conclusions some regions of the Bavarian Alps remained free of ice during the Pleistocene glaciations. The current concepts of phytogeography acknowledge plant survival during cryocratic periods in Bavarian massifs de refuge as well as on the nunatak system. Hitherto in zoogeography, little proof has been offered in support of these assumptions. According to recent investigations the distribution areas of the arachnids Cryphoeca lichenum nigerrima (Hahniidae) and Megabunus lesserti (Phalangiidae) suggest continuous inhabitation of Bavarian refugia since interglacial times. Especially in the Ammergau refugium the persistance of animal life during the last glaciation could be confirmed.
Die Spinnen von Nordtirol (Arachnida, Araneae): Faunistische Synopsis
An overview to the spider fauna of North Tyrol is given from a recent faunistic survey based on field work since 1960 and literature (110 titles since 1867), together with some remarks on the other orders of Arachnida. Early main contributors are AUSSERER (1867), KOCH (1876), and STIPPERGER (1928) about harvest spiders. From N. Tyrol c. 670 spider species now are known (Opiliones 38, Pseudoscorpiones 25, Scorpiones 1, Palpigradi 1). Species of spiders (62) and Opi- liones (10) described from the region are listed, together with locality data, 39 (2) of them still being valid. Two parthenogenetic species, Dysdera hungarica (Dysderidae), Megabunus lesserti (Opilio- nes: Phalangiidae), are rare exceptions. Three chorological types have been emphasized: species en- demic in the Alps as in the Alpine mountain system, arctic alpine species and holarctic mountain spiders occurring discontinuously from Europe to the New world. Limits of distribution area run- ning within N. Tyrol are indicated for the few species involved. Information about changes is scar- ce: there are 4 recent newcomers and Tegenaria atrica C.L. Koch (Agelenidae) later than 1876, and c. 15 species, whose regional populations might have declined and even vanished. Main collecting sites and the habitat types studied are surveyed: of course there is a bias for the surroundings of Innsbruck. Finally, regional distribution patterns and the development of the spider fauna of N. Ty- rol are briefly addressed.
Techno-economic analysis of solar thermal power plants using liquid sodium as heat transfer fluid
Abstract Solar thermal power plants with central receiver and thermal storage are expected to be one key technology in future electricity generation, because they are renewable and due to the thermal storage independent of the current solar radiation. State-of-the-art solar power plants often use molten nitrate salts as heat transfer fluid. The use of liquid sodium instead leads to lower electricity generation costs. Sodium has a high thermal conductivity and thus large heat transfer rates are possible. Hence, a smaller absorber surface is sufficient for the same thermal power. As a result, the sodium receiver achieves a higher efficiency at lower investment cost. Additionally, the aiming strategy, which reduces the peak heat flux on molten salt receivers isn’t necessary for sodium. Even at high heat flux densities, the absorber tubes will be cooled sufficiently due to the high heat transfer coefficients. Therefore, the sodium receiver in this analysis is designed for one single aim point, resulting in a heat flux density of q mean = 1.06 MW / m 2 and q peak = 2.99 MW / m 2 . The state-of-the-art system with molten salt considers q mean = 0.51 MW / m 2 and q peak = 1.0 MW / m 2 . The presented techno-economic analysis of two sodium based concepts compared to a reference system with molten salt results in up to 16% lower electricity generation costs.