No abstract

Biogas effluent (BE) is a potential source of fertilizer for rice. Alternate wetting and drying (AWD) irrigation based on surface water level can increase rice grain yield (GY), but its effect under BE application is still unclear. To test whether AWD can increase GY under BE application, we conducted a mesocosm experiment under screen-house conditions in Can Tho, Vietnam. We measured rice growth and yield under three nitrogen (N) treatments-zero-N (Z), synthetic fertilizer (SF), and BE-and two irrigation regimes-continuous flooding (CF) and AWD with a re-irrigation threshold of 15 cm below the soil surface. Chlorophyll content (SPAD) and leaf color chart (LCC) values were higher in SF than in BE, but plant height was comparable. Although GY was not significantly different between CF and AWD, AWD increased it by 12% in BE relative to CF. All N use efficiency (NUE) indices (apparent N recovery, agronomic NUE, and internal NUE) were comparable between AWD and CF in BE and SF. The results indicate that AWD irrigation is feasible under the application of cattle BE and the combination can improve rice GY.

Type 6201 aluminium alloy wires are produced by drawing 4.7 mm diameter billet-on-billet extruded redraw rod down to 2.7 mm diameter wires. Before drawing, the first group of redraw rod coils was annealed at 480oC for 4 hours to reduce the hardness of the redraw rod. The second group of redraw rod coils was drawn without annealing. With each group of redraw rod, after drawing, some wire coils were solution heat treated, then artificially aged or naturally aged. The other wire coils were artificially aged or naturally aged without solution heat treatment. Mechanical properties of the wires were assessed by a tensile testing machine (model UTM-1000)With suitable aging temperature and aging time, wires produced from each group of redraw rod coils with or without solution heat treatment attain tensile requirements of ASTM B398, but wires produced with solution heat treatment attain higher elongation than wires produced without solution heat treatment.

Chemical compositions and microstructures affect on mechanical – physical and working properties of aluminium and aluminum alloys. Transition elements, such as Ti, V, Cr, Zr in solid solution greatly reduce the electrical conductivity of aluminium and its alloys. For reduction of detrimental effects of transition elements, Al-B master alloys are added into molten aluminium to occur reactions of boron and transition elements to form diborides of titanium, vanadium, chromium and zirconium, which are markedly insoluble in molten aluminium, then these transition elements have an insignificant effects on conductivity. In addition, Al-B master alloys is also used as a grain refiner of aluminium and aluminium alloys. Aluminium borides particles in Al-B master alloys act as substrates for heterogeneous nucleation of aluminium and its alloys. Al-B master alloys are prepared from low cost materials, such as boric acid H3BO3 and cryolite Na3AlF6, by simple melting method, easily realize in electrical wire and cable factories.