Comparison of two soil tillage treatments for winter barley-soybean growing based only on residual nitrogen after soybean

The winter barley crop growing has not been adequately researched regarding soil tillage systems, especially in crop rotation with the soybean, both crops gaining importance as food or fodder. Also, productivity of such crop rotation in low nitrogen environment is especially interesting for organic crop growing, where mineral nitrogen fertilization is not allowed. The research on two soil tillage systems, the conventional one, based on mouldboard ploughing (PLOW) and reduced soil tillage, based on discharrowing (DISC), with no other nitrogen source except symbiotic soybean bacterial fixation, was conducted at the experimental site Bokšić (Croatia), during the seasons 2004/05 and 2005/06. Results showed low but stable yields of winter barley, between 2.1 and 2.6 t ha-1, where PLOW treatment recorded lower yield than DISC in 2005, and usual soybean yields (between 2.8 and 3.4 t ha-1), with higher soybean grain yields for PLOW only in 2006. The absolute mass and hectolitre mass did not show any statistical differences among treatments either

GARNETS OF MICA-SCHISTS FROM CRNI VRH AND RESAVSKI HUMOVI (SERBIA)

Metamorphic rocks of the Crni Vrh and Resavski Humovi area belong to the north-northwestern part of the Serbo-Macedonian Composite Terrane and consist of different types of mica-schists, gneisses and amphibolites. Mica-schists are composed of biotite, muscovite, garnet, staurolite, kyanite, small quantity of Kfeldspar, acid plagioclase and quartz. Accessory minerals are apatite, zircon, tourmaline and ilmenite. Garnets in mica-schists from both localities occur as subhedral to anhedral porphyroblasts from 0.2 to 10mm in size. Most garnets are oriented parallel to the dominant foliation. Garnets from the Crni Vrh mica-schists contain more spesartine component than garnets from Resavski Humovi, while almandine component show opposite tendency. The difference between those garnets is clearly visible, as well as zonality expressed through the increase of almandine component from center to the grain rim. The spesartine component as mentioned above, shows the opposite tendency. Using different geothermometers and geobarometers it was found that mica-schists from Crni Vrh were formed at temperatures from 550-600°C and pressures from 6-6.2 kbar, while micaschists from Resavski Humovi developed at slightly lower temperatures (520-560°C) and at some higher pressures (7-7.3 kbar)

High School Class for Gifted Pupils in Physics and Sciences and Pupils` Skills Measured by Standard and Pisa Test

The ``High school class for students with special abilities in physics`` was founded in Nis, Serbia in 2003. The basic aim of this project has been introducing a broadened curriculum of physics, mathematics, computer science, as well as chemistry and biology. We present analysis of the pupils` skills in solving rather problem oriented test, as PISA test, and compare their results with the results of pupils who study under standard curricula. Analysis of achievement data should clarify what are benefits of introducing in school system track for gifted students. Additionally, item analysis helps in understanding and improvement of learning strategies efficacy.Comment: 6 pages, Talk given at 7th International Conference of the Balkan Physical Union, Alexandruoplos, Greece, 9-13 September 2009. To be published in AIP Conf.Pro

Interpretation of the Friction Coefficient During Reciprocating Sliding of Ti6Al4V Alloy Against Al2O3

Tribological behaviour of Ti6Al4V alloy, during linear reciprocating sliding against alumina, at nanotribometer (ball-on-flat type of contact) was investigated. Experiments were carried out for sliding in Ringer's solution, over a range of loads (100 - 1000 mN) and speeds (4 - 12 mm/s). Friction behaviour of the contact pairs was investigated by analysis of the dynamic friction coefficient plots and effective root mean square (rms) coefficient of friction, COFrms. Presented mathematical envelopes of dynamic coefficient of friction curves and averaged envelope signals provided additional explanation of one calculated COFrms value. Envelopes of dynamic coefficient of friction enabled easier determination of different periods during sliding, which were further related to wear mechanisms

Corrosion Behavior of the As-cast and Heat-treated ZA27 Alloy

Corrosion behaviour of the as-cast and heat-treated ZA27 alloy was examined. The alloy was prepared by conventional melting and casting route and then thermally processed by applying T4 heat treatment regime (solutionizing at 370 °C for 3 hours followed by water quenching and natural aging). Corrosion rate of the as-cast and heat-treated ZA27 alloy was determined in 3.5 wt. % NaCl solution through immersion test using both weight loss method and polarization resistance measurements. It was shown that applied thermal treatment resulted in increased ductility of the heat-treated alloy and had a small beneficial effect on the corrosion resistance of ZA27 alloy

Mechanism of Enhancement in Electromagnetic Properties of MgB2 by Nano SiC Doping

A comparative study of pure, SiC, and C doped MgB2 wires has revealed that the SiC doping allowed C substitution and MgB2 formation to take place simultaneously at low temperatures. C substitution enhances Hc2, while the defects, small grain size, and nanoinclusions induced by C incorporation and low-temperature processing are responsible for the improvement in Jc. The irreversibility field (Hirr) for the SiC doped sample reached the benchmarking value of 10 T at 20 K, exceeding that of NbTi at 4.2 K. This dual reaction model also enables us to predict desirable dopants for enhancing the performance properties of MgB2