Three-dimensional hydrogen-bonded structures in the hydrated proton-transfer salts of isonipecotamide with the dicarboxylic oxalic and adipic acid analogues

The structures of the 1:1 hydrated proton-transfer compounds of isonipecotamide (piperidine-4-carboxamide) with oxalic acid, 4-carbamoylpiperidinium hydrogen oxalate dihydrate, C6H13N2O+·C2HO4-·2H2O, (I), and with adipic acid, bis­(4-car­bam­oylpiperidinium) adipate dihydrate, 2C6H13N2O+·C6H8O42-·2H2O, (II), are three-dimensional hydrogen-bonded constructs involving several different types of enlarged water-bridged cyclic associations. In the structure of (I), the oxalate monoanions give head-to-tail carb­oxy­lic acid O-HOcarboxyl hydrogen-bonding inter­actions, forming C(5) chain substructures which extend along a. The isonipecotamide cations also give parallel chain substructures through amide N-HO hydrogen bonds, the chains being linked across b and down c by alternating water bridges involving both carboxyl and amide O-atom acceptors and amide and piperidinium N-HOcarboxyl hydrogen bonds, generating cyclic R43(10) and R32(11) motifs. In the structure of (II), the asymmetric unit comprises a piperidinium cation, half an adipate dianion, which lies across a crystallographic inversion centre, and a solvent water mol­ecule. In the crystal structure, the two inversion-related cations are inter­linked through the two water mol­ecules, which act as acceptors in dual amide N-HOwater hydrogen bonds, to give a cyclic R42(8) association which is conjoined with an R44(12) motif. Further N-HOwater, water O-HOamide and piperidinium N-HOcarbox­yl hydrogen bonds give the overall three-dimensional structure. The structures reported here further demonstrate the utility of the isonipecotamide cation as a synthon for the generation of stable hydrogen-bonded structures. The presence of solvent water mol­ecules in these structures is largely responsible for the non-occurrence of the common hydrogen-bonded amide-amide dimer, promoting instead various expanded cyclic hydrogen-bonding motifs.

Similarity solutions for flow and heat transfer of non-Newtonian fluid over a stretching surface

Similarity solutions are carried out for flow of power law non-Newtonian fluid film on unsteady stretching surface subjected to constant heat flux. Free convection heat transfer induces thermal boundary layer within a semi-infinite layer of Boussinesq fluid. The nonlinear coupled partial differential equations (PDE) governing the flow and the boundary conditions are converted to a system of ordinary differential equations (ODE) using two-parameter groups. This technique reduces the number of independent variables by two, and finally the obtained ordinary differential equations are solved numerically for the temperature and velocity using the shooting method. The thermal and velocity boundary layers are studied by the means of Prandtl number and non-Newtonian power index plotted in curves.

Negative-ion photoelectron spectroscopy, gas-phase acidity, and thermochemistry of the peroxyl radicals CH3OO and CH3CH2OO

Methyl, methyl-d(3), and ethyl hydroperoxide anions (CH3OO-, CD3OO-, and CH3CH2OO-) have been prepared by deprotonation of their respective hydroperoxides in a stream of helium buffer, gas. Photodetachment with 364 nm (3.408 eV) radiation was used to measure the adiabatic electron affinities: EA[CH3OO, (X) over tilde (2)A"] = 1.161 +/- 0.005 eV, EA[CD3OO, (X) over tilde (2)A"] = 1.154 +/- 0.004 eV, and EA[CH3CH2OO, (X) over tilde (2)A"] = 1.186 +/- 0.004 eV. The photoelectron spectra yield values for the term energies: DeltaE((X) over tilde 2A"-(A) over tilde 2A')[CH3OO] = 0.914 +/- 0.005 eV, DeltaE((X) over tilde (2)A"-(A) over tilde 2A') [CD3OO] = 0.913 +/- 0.004 eV, and DeltaE((X) over tilde (2)A"-(A) over tilde (2)A')[CH3CH2OO] = 0.938 +/- 0.004 eV. A localized RO-O stretching mode was observed near 1100 cm(-1) for the ground state of all three radicals, and low-frequency R-O-O bending modes are also reported. Proton-transfer kinetics of the hydroperoxides have been measured in a tandem flowing afterglow-selected ion flow tube k(FA-SIFT) to determine the gas-phase acidity of the parent hydroperoxides: Delta (acid)G(298)(CH3OOH) = 367.6 +/- 0.7 kcal mol(-1), Delta (acid)G(298)(CD3OOH) = 367.9 +/- 0.9 kcal mol(-1), and Delta (acid)G(298)(CH3CH2OOH) = 363.9 +/- 2.0 kcal mol(-1). From these acidities we have derived the enthalpies of deprotonation: Delta H-acid(298)(CH3OOH) = 374.6 +/- 1.0 kcal mol(-1), Delta H-acid(298)(CD3OOH) = 374.9 +/- 1.1 kcal mol(-1), and Delta H-acid(298)(CH2CH3OOH) = 371.0 +/- 2.2 kcal mol(-1). Use of the negative-ion acidity/EA cycle provides the ROO-H bond enthalpies: DH298(CH3OO-H) 87.8 +/- 1.0 kcal mol(-1), DH298(CD3OO-H) = 87.9 +/- 1.1 kcal mol(-1), and DH298(CH3CH2OO-H) = 84.8 +/- 2.2 kcal mol(-1). We review the thermochemistry of the peroxyl radicals, CH3OO and CH3CH2OO. Using experimental bond enthalpies, DH298(ROO-H), and CBS/APNO ab initio electronic structure calculations for the energies of the corresponding hydroperoxides, we derive the heats of formation of the peroxyl radicals. The "electron affinity/acidity/CBS" cycle yields Delta H-f(298)[CH3OO] = 4.8 +/- 1.2 kcal mol(-1) and Delta H-f(298)[CH3CH2OO] = -6.8 +/- 2.3 kcal mol(-1).

Magnetic convection heat transfer in an open ended enclosure filled with paramagnetic fluids

Numerical simulations of thermomagnetic convection of paramagnetic fluids placed in a micro-gravity condition (g nearly 0) and under a uniform vertical gradient magnetic field in an open ended square enclosure with ramp heating temperature condition applied on a vertical wall is investigated in this study. In presence of the strong magnetic gradient field thermal convection of the paramagnetic fluid might take place even in a zero-gravity environment as a direct consequence of temperature differences occurring within the fluid. The thermal boundary layer develops adjacent to the hot wall as soon as the ramp temperature condition is applied on it. There are two scenario that can be observed based on the ramp heating time. The steady state of the thermal boundary layer can be reached before the ramp time is finished or vice versa. If the ramp time is larger than the quasi-steady time then the thermal boundary layer is in a quasi-steady mode with convection balancing conduction after the quasi-steady time. Further increase of the heat input simply accelerates the flow to maintain the proper thermal balance. Finally, the boundary layer becomes completely steady state when the ramp time is finished. Effects of magnetic Rayleigh number, Prandtl number and paramagnetic fluid parameter on the flow pattern and heat transfer are presented.

A SiC-based matrix converter topology for inductive power transfer system

Typical inductive power transfer (IPT) systems employ two power conversion stages to generate a high-frequency primary current from low-frequency utility supply. This paper proposes a matrix-converter-based IPT system, which employs high-speed SiC devices to facilitate the generation of high-frequency current through a single power conversion stage. The proposed matrix converter topology transforms a three-phase low-frequency voltage system to a high-frequency single-phase voltage, which, in turn, powers a series compensated IPT system. A comprehensive mathematical model is developed and power losses are evaluated to investigate the efficiency of the proposed converter topology. Theoretical results are presented with simulations, which are performed in MATLAB/Simulink, in comparison to a conventional two-stage converter. Experimental evident of a prototype IPT system is also presented to demonstrate the applicability of the proposed concept.

Mode matching pursuit for estimating dominant modes in bulk power grid

This study presents a general approach to identify dominant oscillation modes in bulk power system by using wide-area measurement system. To automatically identify the dominant modes without artificial participation, spectral characteristic of power system oscillation mode is applied to distinguish electromechanical oscillation modes which are calculated by stochastic subspace method, and a proposed mode matching pursuit is adopted to discriminate the dominant modes from the trivial modes, then stepwise-refinement scheme is developed to remove outliers of the dominant modes and the highly accurate dominant modes of identification are obtained. The method is implemented on the dominant modes of China Southern Power Grid which is one of the largest AC/DC paralleling grids in the world. Simulation data and field-measurement data are used to demonstrate high accuracy and better robustness of the dominant modes identification approach.

Heat transfer analysis of viscous incompressible fluid by combined natural convection and radiation in an open cavity

The effect of radiation on natural convection of Newtonian fluid contained in an open cavity is investigated in this study. The governing partial differential equations are solved numerically using the Alternate Direct Implicit method together with the Successive Over Relaxation method. The study is focused on studying the flow pattern and the convective and radiative heat transfer rates are studied for different values of radiation parameters namely, the optical thickness of the fluid, scattering albedo, and the Planck number. It was found that in the optically thin limit, an increase in the optical thickness of the fluid raises the temperature and radiation heat transfer of the fluid. However, a further increase in the optical thickness decreases the radiative heat transfer rate due to increase in the energy level of the fluid, which ultimately reduces the total heat transfer rate within the fluid.

Practice and procedure - District Court Act 1967 s79 - transfer of proceeding pending in Magistrates Court to District Court

In Lambert v Surplice [2004] QDC 092 McGill DCJ considered the extent to which the court should exercise a discretion on an application under s79 of the District Court Act 1967 to transfer a proceeding pending in the Magistrates Court to the District Court.

Enhanced coloration efficiency for electrochromic devices based on anodized N2O5 / Electrodeposited MoO3 Binary Systems

There is a continuous quest for developing electrochromic (EC)transition metal oxides (TMOs) with increased coloration efficiency. As emerging TMOs, Nb2O5 films, even those of ordered anodized nanochannels, have failed to produce the required EC performance for practical applications. This is attributed to limitations presented by its relatively wide bandgap and low capacity for accommodating ions. To overcome such issues, MoO3 was electrodeposited onto Nb2O5 nanochannelled films as homogeneously conformal and stratified α-MoO3 coatings of different thickness. The EC performance of the resultant MoO3 coated Nb2O5 binary system was evaluated. The system exhibited a coloration efficiency of 149.0 cm2 C−1, exceeding that of any previous reports on MoO3 and Nb2O5 individually or their compounds. The enhancement was ascribed to a combination of the reduced effective bandgap of the binary system, the increased intercalation probability from the layered α-MoO3 coating, and a high surface-tovolume ratio, while the Nb2O5 nanochannelled templates provided stability and low impurity pathways for charge transfer to occur.

Liquid metal/metal oxide frameworks

A new platform described as the liquid metal/metal oxide (LM/MO) framework is introduced. The constituent spherical structures of these frameworks are made of micro- to nanosized liquid metal spheres and nanosized metal oxides, combining the advantages of both materials. It is shown that the diameters of the spheres and the stoichiometry of the structures can be actively controlled. Additionally, the liquid suspension of these spheres demonstrates tuneable plasmon resonances. These spherical structures are assembled to form LM/MO frameworks which are capable of demonstrating high sensitivity towards low concentrations of heavy metal ions, and enhanced solar light driven photocalalytic activities. These demonstrations imply that the LM/MO frameworks are a suitable candidate for the development of future high performance electronic and optical devices.

Thin single-walled carbon nanotubes with narrow chirality distribution : constructive interplay of plasma and Gibbs–Thomson effects

Multiscale, multiphase numerical modeling is used to explain the mechanisms of effective control of chirality distributions of single-walled carbon nanotubes in direct plasma growth and suggest effective approaches to further improvement. The model includes an unprecedented combination of the plasma sheath, ion/radical transport, species creation/loss, plasma–surface interaction, heat transfer, surface/bulk diffusion, graphene layer nucleation, and bending/lift-off modules. It is shown that the constructive interplay between the plasma and the Gibbs–Thomson effect can lead to the effective nucleation and lift-off of small graphene layers on small metal catalyst nanoparticles. As a result, much thinner nanotubes with narrower chirality distributions can nucleate at much lower process temperatures and pressures compared to thermal CVD. This approach is validated by a host of experimental results, substantially reduces the amounts of energy and atomic matter required for the nanotube growth, and can be extended to other nanoscale structures and materials systems, thereby nearing the ultimate goal of energy- and matter-efficient nanotechnology.

Atmospheric-pressure discharges for the fabrication of surface-based metal nanostructures

Various reactor configurations for generating atmospheric-pressure discharges were tested, and several types of nanostructures, including Mo nanoflakes, were successfully synthesized. Here, we present photographs of the discharges, as well as SEM images of representative nanostructures.

Nanoscale transfer of energy and matter in plasma–surface interactions

The main issues related to control of energy and matter in hierarchical low-temperature plasma-solid systems used in nanoscale synthesis and processing are critically examined. A conceptual approach to identify the most effective carriers and transport mechanisms of energy and matter at the nano- and subnanometer scales in plasma-aided nanofabrication is proposed. This approach is highly relevant to the envisaged energy- and matter-efficient plasma-based production of the next-generation advanced nanomaterials for applications in the energy, environment, food, water, health, and security technologies critically needed for a sustainable future.

Plasma/ion-controlled metal catalyst saturation : enabling simultaneous growth of carbon nanotube/nanocone arrays

It is shown that the simultaneous saturation of Ni nanoparticles used as catalyst for vertically aligned carbon nanotube and nanocone arrays can be improved in low-temperature plasma- or ion-assisted processes compared with neutral gas-based routes. The results of hybrid multiscale numerical simulations of the catalyst nanoarrays (particle sizes of 2 and 10 nm) saturation with carbon show the possibility of reducing the difference in catalyst incubation times for smallest and largest catalyst particles by up to a factor of 2. This approach is generic and provides process conditions for simultaneous nucleation and growth of uniform arrays of vertically aligned nanostructures. © 2008 American Institute of Physics.

Atmospheric-microplasma-assisted nanofabrication : metal and metal–oxide nanostructures and nanoarchitectures

In this paper, we report on the fabrication of Mo-oxide nanostructures and nanoarchitectures using an atmospheric-microplasma (AMP) system. This AMP system shows a high degree of flexibility and is capable of producing several different nanostructures and nanoarchitectures by varying the process parameters. The low-cost and simplicity of the process are important characteristics for nanomanufacturing, and AMPs offer such advantages. In addition, AMPs have shown the ability of promoting self-organization of nanostructures. © 2009 IEEE.