Nanostructural study of NiTiTiO2C coreshell nanoparticles generated by spark discharge method

Abstract: Nickeltitanium (NiTi) nanoparticles are ultrafine smart materials manifesting shape memory effect at very small scales. We have produced NiTi nanoparticles surrounded by an amorphous carbon shell using an innovative spark discharge system. The resulting nanoparticles were studied using various characterization methods to systematically study their size, morphology, size distribution, composition, structure, and thermal behavior. Field-emission scanning electron microscopy and dynamic light-scattering results indicated that the average size of the produced nanoparticles was about 13 nm. High-resolution transmission electron microscopy, energy-dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy showed that all of the particles had a titanium oxide coating covered with a ~ 2 nm-thick carbon layer. X-ray diffraction analysis demonstrated that the carbon and titanium oxide layers were amorphous and confirmed the formation of NiTi nanoparticles. Differential scanning calorimetry demonstrated an austenite to martensite phase transformation behavior in the produced nanoparticles and further indicated the formation of NiTi phases. EDS mapping showed an incomplete oxidation for nanoparticles suggesting that the amorphous carbon and titanium oxide layers synergistically act together as a combined protective layer. These results indicate that our novel spark discharge generator is an effective system for the synthesis of NiTi nanoparticles coated with a continuous film of carbon

Prioritization of Strategic Agricultural Crops in Alborz Province Using the Fuzzy Delphi Method and The Analytical Hierarchy Process (AHP)

Alborz province with an area of about 5121.7 km2 has about 0.31% of the total area of the country. The total arable area of the province is about 48954 hectares. Water, land and capital are the most important factors for agricultural production. By understanding the subjective beliefs, decision-making criteria and economic incentives of local farmers, the priority of crops can be achieved with the maximum profitability of farmers and the least damage to the resources (water and land). The combination of Fuzzy Delphi techniques and methods of integrating analytical hierarchy process (AHP) can be an appropriate approach for achieving this goal. By employing the above combination of Fuzzy and AHP techniques, the priorities of the strategic agricultural crops in Alborz province achieved as wheat, barley, corn silage, alfalfa, cotton and canola, with final priority weighting factors of 0.496, 0.403, 0.354, 0.320, 0.183, and 0.090, respectively. By comparing the decision criteria it has been determined that the farmers prefer the amount of cultivation area, net income, production costs and livestock needs with the relative importance factors of 0.487, 0.410, 0.346 and 0.188, respectively. Among all prioritization criteria, the cultivated area had the highest priority. Water shortage, labor costs, lack of financial support, and governmental purchase allowance for wheat, were the main reasons for shifting the cultivated area towards wheat cultivation with total area of 14350 hectares

Generation of NiTi nanoparticles via high voltage spark discharge in inert gas

Spark discharge method in inert gas, due to simplicity, no need for complex equipment and raw materials, ability to produce high-purity nanoparticles and mix metallic nanoparticles, is considered a susceptible method for the synthesis of nanoparticles with narrow size distribution. This method is capable to produce nanoparticles of electrical conductor materials and semiconductors. Also, with small changes in spark discharge system, this method can be capable to deposit thin layers of nanoparticles. Now, this method has been used for producing carbon, metal, alloy and metal oxide nanoparticles. Primary objective of this study was to construct a high voltage electrical discharge system. Next step was the synthesis of NiTi alloy nanoparticles in argon atmosphere, using the same Ni-50at%Ti alloy as electrodes. Characterization of NiTi nanoparticles by FESEM, EDX, DLS and HRTEM helps to determine the NiTi nanoparticles size distribution, morphology and composition. The results demonstrated primary nanoparticles ranging from 10 nm to 20 nm in size with a composition close to that of the electrodes

Damaged Airplane Trajectory Planning Based on Flight Envelope and Motion Primitives

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140549/1/1.c032422.pd