On-demand fuzzy clustering and ant-colony optimisation based mobile data collection in wireless sensor network

Wireless Networks - In a wireless sensor network (WSN), sensor nodes collect data from the environment and transfer this data to an end user through multi-hop communication. This results in high...     

Cultivation impacts nitrogen transformation in Indian forest ecosystems

Two forests and two croplands, converted from the forest ecosystem were studied for 2 years to quantify inorganic N, nitrification, N-mineralization and microbial-N. The available N-pool ranged from 15.23 μg g⁻¹ to 19.84 μg g⁻¹, microbial-N from 20.6 μg g⁻¹ to 80.02 μg g⁻¹ with maximum values in summer season and minimum values in the rainy season. The trend for nitrification and N-mineralization was opposite to that of the size of available N-pool. Mean annual net nitrification rates ranged from 7.07 μg g⁻¹ month⁻¹ to 44.84 μg g⁻¹ month⁻¹ (0.17–1.39 μg g⁻¹ day⁻¹) and net N-mineralization from 6.56 μg g⁻¹ month⁻¹ to 48.53 μg g⁻¹ month⁻¹ (0.21–1.56 μg g⁻¹ day⁻¹). On an average, the pool of available N was slightly higher by 4.81%, while the microbial-N was declined substantially by 41.78% after the conversion of forest into cropland. Cultivation reduced the mean annual net nitrification and net N-mineralization, respectively by 50.71% and 47.67%. Interestingly, seasonal moisture content is negatively correlated to microbial-N and inorganic N and positively related to nitrification and N-mineralization.     

Studies on the target conditioning for deposition of LiCoO2 films

Deposition of good quality thin films of Lithium Cobalt Oxide (LiCoO₂), by sputtering is preceded by target conditioning, which dictates the surface composition, morphology and electrochemical performance of the deposited film. Sputtering from a virgin target surface, results in films with excess of the more reactive elements. The concentration of these reactive elements in the films decreases until the system reaches a steady state after sufficient sputtering from the target. This paper discusses the deposition kinetics in terms of target conditioning of LiCoO_2. The composition, morphology and texturing of deposited film during various hours of sputtering were analyzed using X-ray photoelectron spectroscopy (XPS) and Field Emission Scanning electron microscopy (FESEM). The compositional stability is not observed in the films formed during the initial hours of sputtering from the fresh target, which becomes stable after several hours of sputtering. The Li and Co concentration in the films deposited subsequently is found to be varying and possible causes are discussed. After the compositional stability is reached, electrochemical analysis of LiCoO₂ thin films was performed, which shows a discharge capacity of 129 μAh/cm².     

Analysis and price prediction of cryptocurrencies for historical and live data using ensemble-based neural networks

Knowledge and Information Systems - The popularity of cryptocurrencies has been on the rise with the emergence of blockchain technologies. There have been enormous investments in the cryptocurrency...     

Biosynthesis and Characterization of Copper Nanoparticles Using Shewanella oneidensis: Application for Click Chemistry

Copper nanoparticles (Cu‐NPs) have a wide range of applications as heterogeneous catalysts. In this study, a novel green biosynthesis route for producing Cu‐NPs using the metal‐reducing bacterium, Shewanella oneidensis is demonstrated. Thin section transmission electron microscopy shows that the Cu‐NPs are predominantly intracellular and present in a typical size range of 20–40 nm. Serial block‐face scanning electron microscopy demonstrates the Cu‐NPs are well‐dispersed across the 3D structure of the cells. X‐ray absorption near‐edge spectroscopy and extended X‐ray absorption fine‐structure spectroscopy analysis show the nanoparticles are Cu(0), however, atomic resolution images and electron energy loss spectroscopy suggest partial oxidation of the surface layer to Cu₂O upon exposure to air. The catalytic activity of the Cu‐NPs is demonstrated in an archetypal “click chemistry” reaction, generating good yields during azide‐alkyne cycloadditions, most likely catalyzed by the Cu(I) surface layer of the nanoparticles. Furthermore, cytochrome deletion mutants suggest a novel metal reduction system is involved in enzymatic Cu(II) reduction and Cu‐NP synthesis, which is not dependent on the Mtr pathway commonly used to reduce other high oxidation state metals in this bacterium. This work demonstrates a novel, simple, green biosynthesis method for producing efficient copper nanoparticle catalysts.     

Stress Alleviation and Crop Improvement Using Silicon Nanoparticles in Agriculture: a Review

Silicon - Silicon (Si) is not considered as essential element for plant growth and development but it provides benefits to the plants in several ways. Due to distinguishing physiological features,...     

Knoop hardness anisotropy in anthracene and phenanthrene single crystals

Microhardness anisotropy in single crystals of anthracene and phenanthrene has been observed by the Knoop indentation technique. The Knoop hardness variation with respect to the [010] direction shows opposite trends. Both these crystals have the same crystal structure and space group. The present observations are explained in terms of orientation and disposition of molecules in the unit cells.     

Synthesis and evaluation of properties of poly(p‐phenylenevinylene) based 1,3,4‐oxadiazole systems for optoelectronics and nonlinear optical applications

Two new π‐conjugated polymers, namely poly(p‐phenylenevinylene‐1,3,4‐oxadiazole) (PPVO) and poly(p‐(nitro‐phenylene)vinylene‐1,3,4‐oxadiazole) (PNPVO), were synthesized and characterized. The Gilch polymerization technique, using dihalo derivatives of 1,3,4‐oxadiazoles, was employed to synthesize them under mild reaction conditions. The macromolecules exhibit good solubility in dimethylformamide, formamide and dimethyl sulfoxide and thus effectively address the insolubility issues associated with many oxadiazole derivatives for device fabrication. They show bright luminescence in the blue‐green region of the electromagnetic spectrum and have optical band gaps suited for an emissive layer in organic light‐emitting devices. PPVO and PNPPO show good non‐linear optical responses also in solution phase, with third‐order nonlinear susceptibilities of the order of 10^?12esu. Interestingly, they exhibit good antimicrobial characteristics under examination with Escherichia coli and Staphylococcus. The results prove that these macromolecules are ideal materials to use as emissive layers in various light‐emitting devices and NLO applications. The excellent antimicrobial activity can be utilized for their applications in clinical and healthcare areas. © 2016 Society of Chemical Industry     

Sputter deposited LiPON thin films from powder target as electrolyte for thin film battery applications

Lithium phosphorus oxynitride (LiPON) thin films as solid electrolytes were prepared by reactive radio frequency (rf) magnetron sputtering from Li₃PO₄ powder compact target. High deposition rates and ease of manufacturing powder target compared with conventional ceramic Li₃PO₄ targets offer flexibility in handling and reduce the cost associated. Rf power density varied from 1.7 Wcm^− 2 to 3 Wcm^− 2 and N₂ flow from 10 to 30 sccm for a fixed substrate to target distance of 4 cm for best ionic conductivity. The surface chemical analysis done by X-ray photoelectron spectroscopy showed incorporation of nitrogen into the film as both triply, N_t and doubly, N_d coordinated form. With increased presence of N_t, ionic conductivity of LiPON was found to be increasing. The electrochemical impedance spectroscopy of LiPON films confirmed an ionic conductivity of 1.1 × 10^− 6 Scm^− 1 for optimum rf power and N₂ flow conditions.     

Effect of N_2 and O_2 on OH radical production in an atmospheric helium microwave plasma jet

UV-pulsed laser cavity ringdown spectroscopy of the hydroxyl radical OH(A–X)(0–0)band in the wavelength range of 306–310 nm was employed to determine absolute number densities of OH in the atmospheric helium plasma jets generated by a 2.45 GHz microwave plasma source.The effect of the addition of molecular gases N_2 and O_2 to He plasma jets on OH generation was studied.Optical emission spectroscopy was simultaneously employed to monitor reactive plasma species.Stark broadening of the hydrogen Balmer emission line(H_β)was used to estimate the electron density nein the jets.For both He/N_2 and He/O_2 jets, newas estimated to be on the order of 10~(15)cm~(-3).The effects of plasma power and gas flow rate were also studied.With increase in N_2 and O_2 flow rates, netended to decrease.Gas temperature in the He/O_2 plasma jets was elevated compared to the temperatures in the pure He and He/N_2 plasma jets.The highest OH densities in the He/N_2 and He/O_2 plasma jets were determined to be 1.0?×10~(16)molecules/cm~3 at x?=?4 mm(from the jet orifice)and 1.8?×?10~(16)molecules/cm~3 at x=3 mm, respectively.Electron impact dissociation of water and water ion dissociative recombination were the dominant reaction pathways, respectively, for OH formation within the jet column and in the downstream and far downstream regions.The presence of strong emissions of the N_2~+ bands in both He/N_2 and He/O_2 plasma jets, as against the absence of the N_2~+ emissions in the Ar plasma jets, suggests that the Penning ionization process is a key reaction channel leading to the formation of N_2~+ in these He plasma jets.