Effect of microstructure on the stability of retained austenite in transformation-induced-plasticity steels

Two Fe-0.2C-1.55Mn-1.5Si (in wt pet) steels, with and without the addition of 0.039Nb (in wt pet), were studied using laboratory rolling-mill simulations of controlled thermomechanical processing. The microstructures of all samples were characterized by optical metallography, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The microstructural behavior of phases under applied strain was studied using a heat-tinting technique. Despite the similarity in the microstructures of the two steels (equal amounts of polygonal ferrite, carbide-free bainite, and retained austenite), the mechanical properties were different. The mechanical properties of these transformation-induced-plasticity (TRIP) steels depended not only on the individual behavior of all these phases, but also on the interaction between the phases during deformation. The polygonal ferrite and bainite of the C-Mn-Si steel contributed to the elongation more than these phases in the C-Mn-Si-Nb-steel. The stability of retained austenite depends on its location within the microstructure, the morphology of the bainite, and its interaction with other phases during straining. Granular bainite was the bainite morphology that provided the optimum stability of the retained austenite.<br /

Characterizing the scent and chemical composition of Panthera leo marking fluid using solid-phase microextraction and multidimensional gas chromatography–mass spectrometry-olfactometry

Lions (Panthera leo) use chemical signaling to indicate health, reproductive status, and territorial ownership. To date, no study has reported on both scent and composition of marking fluid (MF) from P. leo. The objectives of this study were to: 1) develop a novel method for simultaneous chemical and scent identification of lion MF in its totality (urine + MF), 2) identify characteristic odorants responsible for the overall scent of MF as perceived by human panelists, and 3) compare the existing library of known odorous compounds characterized as eliciting behaviors in animals in order to understand potential functionality in lion behavior. Solid-phase microextraction and simultaneous chemical-sensory analyses with multidimensional gas-chromatography-mass spectrometry-olfactometry improved separating, isolating, and identifying mixed (MF, urine) compounds versus solvent-based extraction and chemical analyses. 2,5-Dimethylpyrazine, 4-methylphenol, and 3-methylcyclopentanone were isolated and identified as the compounds responsible for the characteristic odor of lion MF. Twenty-eight volatile organic compounds (VOCs) emitted from MF were identified, adding a new list of compounds previously unidentified in lion urine. New chemicals were identified in nine compound groups: ketones, aldehydes, amines, alcohols, aromatics, sulfur-containing compounds, phenyls, phenols, and volatile fatty acids. Twenty-three VOCs are known semiochemicals that are implicated in attraction, reproduction, and alarm-signaling behaviors in other species

Utilization of Agriculture Residues and Livestock Waste in Uzbekistan

In Uzbekistan, the integration of crops and livestock, and the use of manure as fertilizer, are traditional practices and is the basis of the farming systems, especially at smallholder level. Nowadays local farmers prefer to use traditional and low-cost technologies for recycling the livestock manure through: anaerobic biodigestion (biodigesters); aerobic biodigestion (composting) and by direct application as organic fertilizer. The livestock waste treatment technique, however, are still too simple and improving is going insignificant. The monitoring system of manure composition, or its allocation to the drop fields is not completely developed. Fuel wood in the arid zones of Uzbekistan is often scarce as a result of deforestation and range degradation, leading to the ever-increasing role of animals as providers of manure for fuel, in addition to means of transport. Phasing out of energy subsidies has also caused that livestock manure, is not returned to the land, but used for heating and cooking, because alternative energy sources are no longer available or affordable. A number of local initiatives on improving waste management procedures waste processing enterprise are implemented in different cities. Biomass has been also a traditional energy source for the production of biogas, and a promising direction of energy in the agrarian sector of Uzbekistan. Uzbekistan has a big potential of biomass energy in the amount of 0.3 million ton of oil equivalent. Energy generated from biomass may satisfy 15-19 % of energy needs of Uzbekistan. Such method of energy production will also resolve the environmental protection issues: use of methane gas considerably reduces CO2 emission into the atmosphere. Besides, the biological residue of the process will provide the country's agriculture with high quality fertilizers. Biogas installations have already been tested at a stock-breeding farm "Milk Agro" in Zangiota village of Tashkent region. Practical results are already achieved: the farm is using biogas for its electricity and heating needs, fertilizers were put on the farm's fields Uzbekistan has also a big potential for production of bioethanol from crop residues and wasted crops: rice straw, wheat straw and corn stover are the most favourable bioethanol feedstock. 15 improved lines tested by ICBA (International Centre for Biosaline Agriculture) in Uzbekistan showed perspectives of sorghum stover for bioethanol production