Channel orientation effect

Channel Length and Inlet Enthalpy Effects and Orientation Effects... 

The titanosilicate version of UTD-1 has been shown to be an effective catalyst for the oxidation of alkanes, alkenes, and alcohols (77-79) by using peroxides as the oxidant. The large pores of Ti-UTD-1 readily accommodate large molecules such as 2,6-di-ferf-butylphenol (2,6-DTBP). The bulky 2,6-DTBP substrate can be converted to the corresponding quinone with activity and selectivity comparable to the mesoporous catalysts Ti-MCM-41 and Ti-HMS (80), where HMS = hexagonal mesoporous silica. Both Ti-UTD-1 and UTD-1 have also been prepared as oriented thin films via a laser ablation technique (81-85). Continuous UTD-1 membranes with the channels oriented normal to the substrate surface have been employed in a catalytic oxidation-separation process (82). At room temperature, a cyclohexene-ferf-butylhydroperoxide was passed through the membrane and epoxidation products were trapped on the down stream side. The UTD-1 membranes supported on metal frits have also been evaluated for the separation of linear paraffins and aromatics (83). In a model separation of n-hexane and toluene, enhanced permeation of the linear alkane was observed. Oriented UTD-1 films have also been evenly coated on small 3D objects such as glass and metal beads (84, 85). 

The zeolite provides the environment for shape selective chemistry and is also a high surface area support on which to disperse platinum in a relatively confined environment. The small platinum crystals within the zeolite channels and the orientation effect of the channel window are responsible for the high efficiency of the Pt-KL catalyst to convert linear paraffin to aromatics. Zeolite KL also provides an electron rich environment to enhance stronger platinum-substrate interaction via stronger platinum-support interaction. A review on the subject can be found in the article written by Meriasdeau and Naccache [85]. 

Independent support for these conclusions regarding the orientation effects in the exit channel is provided by the experiments of Kalamarides et al. " Reaction of K atoms in high Rydberg states with CF3I, K + CF3I -> + F + CFj, was studied... 

Effect of Channel Orientation. For the subcooled boiling region, a study of the effect of channel inclination on critical heat flux is reported by Brusstar and Merte [294]. The channel used by these authors was rectangular in cross section with one side heated. The orientation of this heated surface with respect to the horizontal could be varied between 0 and 360°. At low velocities, a sharp decrease in critical heat flux was observed when the heater surface was downward-facing, as exemplified by the results shown in Fig. 15.119. 

Abstract The electric fields and potential in a pore filled with water are calculated, without using the Poisson-Boltzmann equation. No assumption of macroscopic dielectric behavior is made for the interior of the pore. The field and potential at any position in the pore are calculated for a charge in any other position in the pore, or the dielectric boundary of the pore. The water, represented by the polarizable PSPC model, is then placed in the pore, using a Monte Carlo simulation to obtain an equilibrium distribution. The water, charges, and dielectric boundary, together determine the field and potential distribution in the channel. The effect on an ion in the channel is then dependent on both the field, and the position and orientation of the water. The channel can exist in two major configurations open or closed, in which the open channel allows ions to pass. In addition, there may be intermediate states. The channel has a water filled pore, and a wall... 

Lipscomb et al. (1988) have shown that the flow kinematics in complex flows can be strongly affected due to fibers. However, in the injection molding simulation for flows in narrow channels, the effects can be neglected, and an orientation-flow decoupled simulation approach is used. To understand in which situations the decoupled simulation is allowed, we need to classify the flow regimes. Tucker (1991) has identified four regimes of suspension flows. His classification was based on two dimensionless numbers. The first is the particle number defined by... 

SIMS, and SNMS in rare cases, such as for HgCdJTei samples or some polymers, the sample structure can be modified by the incident ion beam. These effects can often be eliminated or minimized by limitii the total number of particles incident on the sample, increasing the analytical area, or by cooling the sample. Also, if channeling of the ion beam occurs in a crystal sample, this must be included in the data analysis or serious inaccuracies can result. To avoid unwanted channelii, samples are often manipulated during the analysis to present an average or random crystal orientation. 

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