Atomization Characteristics of Camelina-Based Alternative Aviation Fuels Discharging From Dual-Orifice Injector

The atomization characteristics of blends of bioderived camelina hydrogenated renewable jet (HRJ) alternative fuel with conventional aviation kerosene (Jet A-1) discharging into ambient atmospheric air from a dual-orifice atomizer used in aircraft engines are described. The spray tests are conducted in a spray test facility at six different test flow conditions to compare the atomization of alternative fuels with that of Jet A-1. The fuel sprays are characterized in terms of fuel discharge, spray cone angle, drop size distribution, and spray patternation. The measurements of spray drop size distribution are obtained using laser diffraction based Spraytec equipment. The characteristics of fuel discharge and cone angle of alternative fuel sprays do not show any changes from that of Jet A-1 sprays. The characteristics of spray drop size, evaluated in terms of the variation of mean drop size along the spray axis, for the alternative fuel sprays remain unaffected by the variation in fuel properties between the alternative fuels and Jet A-1. The measurements on spray patternation, obtained using a mechanical patternator at a distance 5.1 cm from the atomizer exit, show an enhanced fuel concentration in the vicinity of spray axis region for the alternative fuel sprays discharging from the dual-orifice atomizer.

Controlled material transport and multidimensional patterning at small length scales using electromigration

Electromigration, mostly known for its damaging effects in microelectronic devices, is basically a material transport phenomenon driven by the electric field and kinetically controlled by diffusion. In this work, we show how controlled electromigration can be used to create scientifically interesting and technologically useful micro-/nano-scale patterns, which are otherwise extremely difficult to fabricate using conventional cleanroom practices, and present a few examples of such patterns. In a solid thin-film structure, electromigration is used to generate pores at preset locations for enhancing the sensitivity of a MEMS sensor. In addition to electromigration in solids, the flow instability associated with the electromigration-induced long-range flow of liquid metals is shown to form numerous structures with high surface area to volume ratio. In very thin solid films on non-conductive substrates, solidification of flow-affected region results in the formation of several features, such as nano-/micro-sized discrete metallic beads, 3D structures consisting of nano-stepped stairs, etc.

Alternative Formulation of the Discrete Linear Quadratic Regulator (DLQR)

In this paper, an alternative apriori and aposteriori formulation has been derived for the discrete linear quadratic regulator (DLQR) in a manner analogous to that used in the discrete Kalman filter. It has been shown that the formulation seamlessly fits into the available formulation of the DLQR and the equivalent terms in the existing formulation and the proposed formulation have been identified. Thereafter, the significance of this alternative formulation has been interpreted in terms of the sensitivity of the controller performances to any changes in the states or to changes in the control inputs. The implications of this alternative formulation to adaptive controller tuning have also been discussed.

Experimentally validated Raman Monte Carlo simulation for a cuboid object to obtain Raman spectroscopic signatures for hidden material

In conventional Raman spectroscopic measurements of liquids or surfaces the preferred geometry for detection of the Raman signal is the backscattering (or reflection) mode. For non-transparent layered materials, sub-surface Raman signals have been retrieved using spatially offset Raman spectroscopy (SORS), usually with light collection in the same plane as the point of excitation. However, as a result of multiple scattering in a turbid medium, Raman photons will be emitted in all directions. In this study, Monte Carlo simulations for a three-dimensional layered sample with finite geometry have been performed to confirm the detectability of Raman signals at all angles and at all sides of the object. We considered a non-transparent cuboid container (high density polyethylene) with explosive material (ammonium nitrate) inside. The simulation results were validated with experimental Raman intensities. Monte Carlo simulation results reveal that the ratio of sub-surface to surface signals improves at geometries other than backscattering. In addition, we demonstrate through simulations the effects of the absorption and scattering coefficients of the layers, and that of the diameter of the excitation beam. The advantage of collecting light from all possible 4 angles, over other collection modes, is that this technique is not geometry specific and molecular identification of layers underneath non-transparent surfaces can be obtained with minimal interference from the surface layer. To what extent all sides of the object will contribute to the total signal will depend on the absorption and scattering coefficients and the physical dimensions. Copyright (c) 2015 John Wiley & Sons, Ltd.

Graphene oxide as an optimal candidate material for methane storage

Methane, the primary constituent of natural gas, binds too weakly to nanostructured carbons to meet the targets set for on-board vehicular storage to be viable. We show, using density functional theory calculations, that replacing graphene by graphene oxide increases the adsorption energy of methane by 50%. This enhancement is sufficient to achieve the optimal binding strength. In order to gain insight into the sources of this increased binding, that could also be used to formulate design principles for novel storage materials, we consider a sequence of model systems that progressively take us from graphene to graphene oxide. A careful analysis of the various contributions to the weak binding between the methane molecule and the graphene oxide shows that the enhancement has important contributions from London dispersion interactions as well as electrostatic interactions such as Debye interactions, aided by geometric curvature induced primarily by the presence of epoxy groups. (C) 2015 AIP Publishing LLC.

Cultivation of Pleurotus spp. on a combination of anaerobically digested plant material and various agro-residues

Two species of Pleurotus, Pleurotus florida and Pleurotus flabellatus were cultivated on two agro-residues (paddy straw; PS and coir pith; CP) singly as well as in combination with biogas digester residue (BDR, main feed leaf biomass). The biological efficiency, nutritional value, composition and nutrient balance (C, N and P) achieved with these substrates were studied. The most suitable substrate that produced higher yields and biological efficiency was PS mixed with BDR followed by coir pith with BDR. Addition of BDR with agro-residues could increase mushroom yield by 20-30%. The biological efficiency achieved was high for PS + BDR (231.93% for P. florida and 209.92% for P. flabellatus) and for CP + BDR (14831% for P. florida and 188.46% for P. flabellatus). The OC (organic carbon), TKN (nitrogen) and TP (phosphate) removal of the Pleurotus spp. under investigation suggests that PS with BDR is the best substrate for growing mushroom. (C) 2015 Published by Elsevier Inc. on behalf of International Energy Initiative.

Novel Alternative Splice Variants of Mouse Cdk5rap2

Autosomal recessive primary microcephaly (MCPH) is a rare neurodevelopmental disorder characterized by a pronounced reduction of brain volume and intellectual disability. A current model for the microcephaly phenotype invokes a stem cell proliferation and differentiation defect, which has moved the disease into the spotlight of stem cell biology and neurodevelopmental science. Homozygous mutations of the Cyclin-dependent kinase-5 regulatory subunit-associated protein 2 gene CDK5RAP2 are one genetic cause of MCPH. To further characterize the pathomechanism underlying MCPH, we generated a conditional Cdk5rap2 LoxP/hCMV Cre mutant mouse. Further analysis, initiated on account of a lack of a microcephaly phenotype in these mutant mice, revealed the presence of previously unknown splice variants of the Cdk5rap2 gene that are at least in part accountable for the lack of microcephaly in the mice.

Energy-savvy solid-state and sonochemical synthesis of lithium sodium titanate as an anode active material for Li-ion batteries

Lithium sodium titanate insertion-type anode has been synthesized by classical solid-state (dry) and an alternate solution-assisted (wet) sonochemical synthesis routes. Successful synthesis of the target compound has been realized using simple Na- and Li-hydroxide salts along with titania. In contrast to the previous reports, these energy-savvy synthesis routes can yield the final product by calcination at 650 -750 degrees C for limited duration of 1-10 h. Owing to the restricted calcination duration (dry route for 1-2 h and wet route for 1-5 h), they yield homogeneous nanoscale lithium sodium titanate particles. Sono-chemical synthesis reduces the lithium sodium titanate particle size down to 80-100 nm vis-a-vis solid-state method delivering larger (200-500 nm) particles. Independent of the synthetic methods, the end products deliver reversible electrochemical performance with reversible capacity exceeding 80 mAh.g(-1) acting as a 1.3 V anode for Li-ion batteries. (C) 2015 Elsevier B.V. All rights reserved.

Kinematic flow patterns in slow deformation of a dense granular material

The kinematic flow pattern in slow deformation of a model dense granular medium is studied at high resolution using in situ imaging, coupled with particle tracking. The deformation configuration is indentation by a flat punch under macroscopic plane-strain conditions. Using a general analysis method, velocity gradients and deformation fields are obtained from the disordered grain arrangement, enabling flow characteristics to be quantified. The key observations are the formation of a stagnation zone, as in dilute granular flow past obstacles; occurrence of vortices in the flow immediately underneath the punch; and formation of distinct shear bands adjoining the stagnation zone. The transient and steady state stagnation zone geometry, as well as the strength of the vortices and strain rates in the shear bands, are obtained from the experimental data. All of these results are well-reproduced in exact-scale non-smooth contact dynamics simulations. Full 3D numerical particle positions from the simulations allow extraction of flow features that are extremely difficult to obtain from experiments. Three examples of these, namely material free surface evolution, deformation of a grain column below the punch and resolution of velocities inside the primary shear band, are highlighted. The variety of flow features observed in this model problem also illustrates the difficulty involved in formulating a complete micromechanical analytical description of the deformation.

Review on Tin (II) Sulfide (SnS) Material: Synthesis, Properties, and Applications

Tin (II) sulphide (SnS), a direct band gap semiconductor compound, has recently received great attention due to its unique properties. Because of low cost, absence of toxicity, and good abundance in nature, it is becoming a candidate for future multifunctional devices particularly for light conversion applications. Although the current efficiencies are low, the cost-per-Watt is becoming competitive. At room temperature, SnS exhibits stable low-symmetric, double-layered orthorhombic crystal structure, having a = 0.4329, b = 1.1192, and c = 0.3984nm as lattice parameters. These layer-structured materials are of interest in various device applications due to the arrangement of structural lattice with cations and anions. The layers of cations are separated only by van der Waals forces that provide intrinsically chemically inert surface without dangling bonds and surface density of states. As a result, there is no Fermi level pinning at the surface of the semiconductor. This fact leads to considerably high chemical and environmental stability. Further, the electrical and optical properties of SnS can be easily tailored by modifying the growth conditions or doping with suitable dopants without disturbing its crystal structure.In the last few decades, SnS has been synthesized and studied in the form of single-crystals and thin-films. Most of the SnS single-crystals have been synthesized by Bridgeman technique, whereas thin films have been developed using different physical as well as chemical deposition techniques. The synthesis or development of SnS structures in different forms including single-crystals and thin films, and their unique properties are reviewed here. The observed physical and chemical properties of SnS emphasize that this material could has novel applications in optoelectronics including solar cell devices, sensors, batteries, and also in biomedical sciences. These aspects are also discussed.

Synthesis, and crystal and electronic structure of sodium metal phosphate for use as a hybrid capacitor in non-aqueous electrolyte

Energy storage devices based on sodium have been considered as an alternative to traditional lithium based systems because of the natural abundance, cost effectiveness and low environmental impact of sodium. Their synthesis, and crystal and electronic properties have been discussed, because of the importance of electronic conductivity in supercapacitors for high rate applications. The density of states of a mixed sodium transition metal phosphate (maricite, NaMn1/3Co1/3Ni1/3PO4) has been determined with the ab initio generalized gradient approximation (GGA)+Hubbard term (U) method. The computed results for the mixed maricite are compared with the band gap of the parent NaFePO4 and the electrochemical experimental results are in good agreement. A mixed sodium transition metal phosphate served as an active electrode material for a hybrid supercapacitor. The hybrid device (maricite versus carbon) in a nonaqueous electrolyte shows redox peaks in the cyclic voltammograms and asymmetric profiles in the charge-discharge curves while exhibiting a specific capacitance of 40 F g(-1) and these processes are found to be quasi-reversible. After long term cycling, the device exhibits excellent capacity retention (95%) and coulombic efficiency (92%). The presence of carbon and the nanocomposite morphology, identified through X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) studies, ensures the high rate capability while offering possibilities to develop new cathode materials for sodium hybrid devices.

An alternative approach to study nonlinear inviscid flow over arbitrary bottom topography

This paper deals with a new approach to study the nonlinear inviscid flow over arbitrary bottom topography. The problem is formulated as a nonlinear boundary value problem which is reduced to a Dirichlet problem using certain transformations. The Dirichlet problem is solved by applying Plemelj-Sokhotski formulae and it is noticed that the solution of the Dirichlet problem depends on the solution of a coupled Fredholm integral equation of the second kind. These integral equations are solved numerically by using a modified method. The free-surface profile which is unknown at the outset is determined. Different kinds of bottom topographies are considered here to study the influence of bottom topography on the free-surface profile. The effects of the Froude number and the arbitrary bottom topography on the free-surface profile are demonstrated in graphical forms for the subcritical flow. Further, the nonlinear results are validated with the results available in the literature and compared with the results obtained by using linear theory. (C) 2015 Elsevier Inc. All rights reserved.

Flower-like porous cobalt(II) monoxide nanostructures as anode material for Li-ion batteries

In the present study, a microwave-assisted, solution-based route has been employed to obtain porous CoO nano structures. Detailed characterization reveals that the flower-like nanostructures comprise petal-like sheets, each of which is made of an ordered, porous arrangement of crystallites of CoO measuring about 6 nm. TEM analysis shows that each ``petal'' is an oriented aggregate of CoO nanocrystals, such aggregation promoted by the hydroxyl moieties derived from the solution. The structure provides a large specific area as well as the porosity desirable in electrodes in Li-ion batteries. Electrochemical measurements carried out on electrodes made of nanostructured CoO show excellent Li ion-storing capability. A specific capacitance of 779 mAh g(-1) has been measured at a specific current of 100 mA g(-1). Measurements show also excellent cyclability and coulombic efficiency. Impedance spectroscopy provides evidence for charge transfer occurring in the porous networks. (C) 2015 Elsevier B.V. All rights reserved.

Heterostructure composites of rGO/GeO2/PANI with enhanced performance for Li ion battery anode material

A novel solvothermal method has been used for the synthesis of porous ellipsoidal GeO2 particles with oleic acid and oleylamine as solvent and co-surfactant, respectively and its performance has been studied as an anode material for Li ion battery applications. The presence of highly hydrophobic oleic acid and oleylamine on the surface of the as synthesized sample imparts a detrimental effect on its performance. Although removal of the capping agents with glacial acetic acid improves the performance to some extent, a drastic enhancement in both the specific capacity and cycling stability is observed when the nanoparticles are wrapped with rGO/PANI composites at low temperature. (C) 2015 Elsevier B.V. All rights reserved.

Hierarchically porous Li1.2Mn0.6Ni0.2O2 as a high capacity and high rate capability positive electrode material

Layered composite samples of lithium-rich manganese oxide (Li1.2Mn0.6Ni0.2O2) are prepared by a reverse microemutsion route employing a soft polymer template and studied as a positive electrode material. The product samples possess dual porosity with distribution of pores at 3.5 and 60 nm. Pore volume and surface area decrease on increasing the temperature of preparation. Nevertheless, the electrochemical activity of the composite increases with an increase in temperature. The discharge capacity value of the samples prepared at 800 and 900 degrees C is about 240 mA h g(-1) at a specific current of 25 mA g(-1) with a good cycling stability. The composite sample heated at 900 degrees C possesses a high rate capability with a discharge capacity of 100 mA h g(-1) at a specific current of 500 mA g(-1). The high rate capability is attributed to porous nature of the composite sample.