Materials Literature
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<div class="htmlview paragraph">This work attempts a systematic investigation of the effects of flow maldistribution on the light-off behavior of a monolithic catalytic converter. To achieve this goal, a combined chemical reaction model and three-dimensional computational fluid dynamic modeling technique has bee…
<div class="htmlview paragraph">The local variation of the crankshaft's speed in a multicylinder engine is determined by the resultant gas-pressure torque and the torsional deformation of the crankshaft. Under steady-state operation, the crankshaft's speed has a quasi-periodic variation and its harmonic componen…
Raman scattering has been used to probe short-range structural information on lanthanum-doped lead titanate ceramics (LaxPb1−xTiO3) for x, ranging from 0.0 to 0.30. In highly doped samples (x&gt;0.27), x-ray diffraction measurements indicate a cubic structure, although measurements of Raman scattering at temperatu…
High-spin and low-spin complexes of the iron(III) tetrakis( meso -cyclohexyl)porphyrin ((TCHP)Fe III ) have been studied by means of 1-D and 2-D 1 H NMR. The complete assignment of porphyrin and R-imidazole 1 H resonances has been done on the basis of 2-D COSY and NOESY techniques as well as by selective deuteration o…
<div class="htmlview paragraph">A 2-D CFD model was developed to describe the heat transfer, and reaction kinetics in a honeycomb structured ceramic diesel particulate trap. This model describes the steady state as well as the transient behavior of the flow and heat transfer during the trap regeneration processe…
Optical absorption and multiphonon relaxation have been investigated for Nd3+-doped ZnCl2-based glass. The intensity parameters for radiative transitions of Nd3+ were determined to be Ω2=4.97×10−20 cm2, Ω4=7.39×10−20 cm2 and Ω6=5.12×10−20 cm2. All of the Ωt parameters, especially Ω4, of Nd3+ in the ZnCl2-based glass w…
In situ Raman spectra of SiHx, Si–F, and Si–Si vibrations from Si surfaces in HF aqueous solutions are obtained using a highly sensitive confocal microprobe Raman system. Electrochemical roughening pretreatment and laser-assisted roughening procedure enable good quality surface Raman spectra to be obtained. The surfac…
We report the use of a low concentration polymer network to stabilize electric field-induced diffraction gratings in cholesteric liquid crystals. The stabilized gratings can be electrically switched between a zero-field “on” state, which exhibits approximately 75% diffraction efficiency, and a moderate field (typicall…
Metallic oxide films of SrRuO3 deposited on (001) SrTiO3 by pulsed laser deposition have been investigated by transmission electron microscopy (TEM) techniques. These films have a single crystalline structure with an extremely smooth surface. A TEM study of cross-sectional samples shows that the film grew epitaxially…
<div class="htmlview paragraph">Dimethyl Ether has been proposed as alternative fuel for combustion engines. The paper gives a brief overview of resources, production, distribution and use of different automotive fuels and compares Dimethyl Ether with other oxygenated synthetic fuels recently proposed.</div&g…
Using subnatural linewidth Auger-photoelectron coincidence spectroscopy following linearly polarized synchrotron radiation excitation we have measured the triply differential double photoionization cross section of xenon at a photon energy of 97.5 eV. At this photon energy the kinetic energy of the 4 ${d}_{5/2}$ photo…
<div class="htmlview paragraph">Increasing concern, about the health risk due to solid aerosols from engine combustion, has provoked more stringent imission limits, for soot particles in the range of pulmonary intrusion, at critical work-places (e.g. tunnel sites, see <span class="xref">Table 1</span>…
Polycrystalline CrO2 is shown to exhibit a giant magnetoresistance (GMR) at low temperatures. A rapid decrease in the GMR with increasing temperature is correlated with a decrease in the intergranular resistance. Single-crystal CrO2 is a half-metallic ferromagnet, as the data are interpreted to reflect two types of ch…
The emissions performance of catalytic converters under different conditions of flow distribution was investigated. Computational Fluid Dynamics methods were utilised to model the maldistribution effects of different inlet cones. The effects of maldistribution on ageing, light-off and conversion were investigated usin…
Using ab initio molecular dynamics simulations, we have studied the growth mechanisms of boron-nitride (BN) nanotubes. In the experimental conditions of temperature, the behavior of single-wall BN nanotubes strongly depends on their helicity. Open-ended ``zigzag'' tubes close into an amorphouslike tip, preventing furt…
By lifting an epitaxial thin film off its growth substrate, we directly and quantitatively demonstrate how elastic strain can alter the magnetic and electrical properties of single-domain epitaxial SrRuO3 thin films (1000 Å thick) on vicinal (001) SrTiO3 substrates. Free-standing films were then obtained by selective…
The question of how carbon nanotubes (CNT)—believed to be the strongest filaments—relax under tension has been addressed. A dislocation theory applied to a two-dimensional nanocrystal such as the CNT describes the main routes of mechanical relaxation in this molecular structure: a brittle cleavage or, at high temperat…
A series of polyurethanes based on 2,4-toluenediisocyanate (TDI), with different amounts of 3-chloro-1,2-propanediol (CPDO), have been prepared. The process of thermal degradation was monitored by thermogravimetric analysis (TGA) alone or coupled with infrared spectroscopy (TGA/FTIR) and differential scanning calorime…
A phase diagram of a mixture consisting of nematic and smectic liquid crystals has been calculated self-consistently by combining Flory–Huggins (FH) theory for isotropic mixing and Maier–Saupe–McMillan (MSM) theory for smectic-A ordering. However, the MSM theory can be deduced to the original Maier–Saupe (MS) theory f…
Amorphous poly(propylene oxide), PPO (molecular weights, 425 and ∼106), complexed with NaClO4 salt has ionic conductivities as high as 10−5 S/cm at room temperature. In an attempt to directly study the dynamics of the Na+ ions, (I=3/2) nuclear magnetic resonance (NMR) spin-lattice relaxation times, T1, and spin–spin r…