Room-temperature ferromagnetism in graphitic petal arrays

We report room-temperature ferromagnetism of graphitic petal arrays grown on Si substrates by microwave plasma chemical vapor deposition without catalyst. The samples have been characterized by Raman and X-ray photoelectron spectroscopy to confirm the absence of possible ferromagnetic impurities. The petals exhibit ferromagnetic hysteresis with saturation magnetization of ～4.67 emu cm(-3) and coercivity of ～105 Oe at 300 K, comparable to the reported behavior of few-layer graphene. Upon O2 annealing the saturation magnetization and coercivity decreased to 2.1 emu cm(-3) and ～75 Oe respectively. The origin of ferromagnetism is believed to arise from the edge defects and vacancies in the petals.     

A Genetically-Based Latitudinal Cline in the Emission of Herbivore-Induced Plant Volatile Organic Compounds

The existence of predictable latitudinal variation in plant defense against herbivores remains controversial. A prevailing view holds that higher levels of plant defense evolve at low latitudes compared to high latitudes as an adaptive plant response to higher herbivore pressure on low-latitude plants. To date, this prediction has not been examined with respect to volatile organic compounds (VOCs) that many plants emit, often thus attracting the natural enemies of herbivores. Here, we compared genetically-based constitutive and herbivore-induced aboveground vegetative VOC emissions from plants originating across a gradient of more than 10° of latitude (>1,500 km). We collected headspace VOCs from Asclepias syriaca (common milkweed) originating from 20 populations across its natural range and grown in a common garden near the range center. Feeding by specialist Danaus plexippus (monarch) larvae induced VOCs, and field environmental conditions (temperature, light, and humidity) also influenced emissions. Monarch damage increased plant VOC concentrations and altered VOC blends. We found that genetically-based induced VOC emissions varied with the latitude of plant population origin, although the pattern followed the reverse of that predicted—induced VOC concentration increased with increasing latitude. This pattern appeared to be driven by a greater induction of sesquiterpenoids at higher latitudes. In contrast, constitutive VOC emission did not vary systematically with latitude, and the induction of green leafy volatiles declined with latitude. Our results do not support the prevailing view that plant defense is greater at lower than at higher latitudes. That the pattern holds only for herbivore-induced VOC emission, and not constitutive emission, suggests that latitudinal variation in VOCs is not a simple adaptive response to climatic factors.     

Structural,Optical, and Ferroelectric Behaviors of Cu_(1-x)Li_xO(0≤x≤0.09) Nanostructures

We report structural,optical,and ferroelectric behaviors of lithium-doped copper oxide(Cu1-xLixO with x =0.0,0.05,0.07,and 0.09) nanostructures synthesized by hydrothermal method.The XRD pattern indicates the pure phase formation of CuO without any impurity,and the crystallite size is found to be increases for x =0–0.07 and decreases for x =0.09.FESEM analysis shows that the average size of Cu1-xLixO nanostructures increases with the increasing the Li-doping concentrations up to 7% and then decreases for 9% Li doping concentration.Moreover,Raman and photoluminescence spectrum also confirm the phase formation of CuO.A significant reduction in optical band gap is observed up to x =0.07,and then band gap increases for x =0.09 due to segregation of the impurities on the surface or grain boundaries,which may suppress the grain growth and results the enhancement in optical band gap.Moreover,a weak ferroelectricity is observed in CuO nanostructures for pure and 9% Li doping through polarization versus electric field(P–E).     

Effect of accelerated aging on the tensile index of a synthetic insulation paper

This paper explores the possibility of using tensile index as one of the appropriate end point parameters to determine the thermal index of a synthetic insulation paper. The paper samples were aged at three different times and temperatures. The tensile index of fresh as well as aged samples was determined experimentally. The study showed that tensile index could be considered as an appropriate parameter to find the thermal index of the chosen synthetic insulation paper.     

Improvement of fuel properties of cottonseed oil methyl esters with commercial additives

The low temperature operability and oxidative stability of cottonseed oil methyl esters (CSME) were improved with four anti‐gel additives as well as one antioxidant additive, gossypol. Low temperature operability and oxidative stability of CSME was determined by cloud point (CP), pour point (PP), cold filter plugging point (CFPP), and oxidative stability index (OSI). The most significant reductions in CP, PP, and CFPP in all cases were obtained with Technol®, with the average reduction in temperature found to be 3.9 °C. Gunk®, Heet®, and Howe's® were progressively less effective, as indicated by average reductions in temperature of 3.4, 3.0, and 2.8 °C, respectively. In all cases, the magnitude of CFPP reduction was greater than for PP and especially CP. Addition of gossypol, a polyphenolic aldehyde, resulted in linear improvement in OSI (R² = 0.9804). The OSI of CSME increased from 5.0 to 8.3 h with gossypol at a concentration of 1000 ppm.     

Distribution and Prediction of Boundary Shear in Diverging Compound Channels

Measurement of bed shear stress is always a challenging task for engineers. In river engineering, bed shear is a fundamental variable and is important in estimating flow resistance and sediment transport. In this study, experiments are carried out in diverging compound channel with smooth bed (perspex sheet) and rough bed (Gravel) conditions to determine the effect of roughness. The shear velocity is estimated from universal logarithmic law. The effect of geometry and roughness on Von-Karman constant, eddy viscosity coefficient, friction factor is studied. The mass conservation and momentum conservation equations are used to derive apparent shear forces at interface of main channel and floodplain. A genetic algorithm model is developed to predict percentage of shear force (%Sfp) carried by sub-sections. To perform better with less and unseen data K-Fold cross-validation technique is used. The model is compared with available models in literature and it is observed that developed model gave better predictions with low MAPE.

     

Application of Heuristic Approaches for Prediction of Hydrological Drought Using Multi-scalar Streamflow Drought Index

Water Resources Management - Quantification and prediction of drought events are important for planning and management of water resources in coping with climate change scenarios at global and local...     

Effect of Ar heat treatment on oxygenated R1−x Ca x Ba2Cu3O7−δ (R = Y, Sm) superconductors

The influence of heat treatment, at 450°C in Ar environment, on oxygenated (6.72 < 7 – < 6.93) samples of R_1–x Ca _x Ba₂Cu₃O_7– (i.e. R(Ca)-123, with R = Y, Sm) with 0 < x < 0.3 has been investigated. Measurements of oxygen loss, normal state resistivity behaviour (T), superconducting critical temperature T _c and transition widths reveal that Ar treatment effects both the series differently. The Sm(Ca)-123 samples, for all values of x, show a considerable loss of oxygen ((x) = 0.4 to 0.6) and decrease in T _c (T _c(x) = 35 to 55 K). Whereas, surprisingly, the Y(Ca)-123 samples show a much smaller loss of oxygen ((x) = 0 to 0.3), along with a decrease in T _c for x < 0.2 and an increase in it for x > 0.2. In particular, the x = 0.3 sample shows a negligible change in oxygen content accompanied by an increase of 20 K in T _c. These and host of other observations suggest that the presence of Ca may influence the oxygen loss mechanism in these series.