Effect Of Geometrical Arrangement Research Articles

The effect of geometric arrangement on the thermoelectric properties of Phenanthrene coupled to the graphene nanoribbons electrodes

The thermoelectric properties of a Phenanthrene molecule, such as thermopower, electrical conductivity, thermal conductivity and figure of merit, are investigated by applying the non-equilibrium Green's function (NEGF) method combined with the density functional theory (DFT). Phenanthrene is intended to couple to the graphene nanoribbons electrodes in two configurations. The vertical and horizontal orientations of the molecule between the nanoribbons are considered. The results reveal that the thermoelectric properties of the considered structures are dependent on the orientation of Phenanthrene configuration between the electrodes. At high chemical potential, the greatest figure of merit is observed for Phenanthrene, which is vertically attached to the electrodes, because of the small thermal conductivity of this configuration. On the other hand, the symmetric and horizontal configurations of the molecule make it a high-performance thermoelectric device at zero chemical potential.

Experimental and Numerical Investigations on Louvered Fin-and-Tube Heat Exchanger With Variable Geometrical Parameters

The effects of geometrical arrangement on the heat transfer and pressure drop characteristics in compact louvered fin-and-tube heat exchangers were studied experimentally and numerically along with ε−NTU method. Different geometrical parameters including louver angle, louver pitch, louver number, the nonlouvered inlet and exit fin length, and redirection of fluid flow are considered to determine their effects on the flow field. The study is performed for different louver angles varying from θL=12 to 60 deg, and optimal heat transfer rate is obtained at louver angle of θL=28deg. Also, it is found that increasing the louver number, NL, on the fin surface enhances the heat transfer performance. It is shown that the average Nusselt number is increased as the louver pitch is decreased and its optimum value is obtained at Lp=0.9 mm. However, comparing to the effect of louver number, the louver pitch has a small effect on the performance of the heat exchanger. Additionally, the optimum values of nonlouvered inlet and exit fin length and redirection length of fin are obtained with different flow conditions.

Effect of Geometrical arrangement on the electrical conductivity of some successive polymers (Para- polyamide - Meta polyamide)

Effect of Geometrical arrangement on the electrical conductivity of some successive polymers (Para- polyamide - Meta polyamide)

Giant magnetostrictive thin film formation by plasma process

In this study, the effects of geometrical arrangement of substrate on the magnetostriction of the giant magnetostrictive materials film using an ion plating process were discussed. With increasing substrate angle, coercive force remained almost constant value and the in-plane magnetization at 15 kOe was strongly increased. This indicates that the easy direction of magnetization was changed from perpendicular to in-plane by obliquely deposition. The magnetic and magnetostrictive characteristics of the obliquely deposited films were affected by an oblique anisotropy. The oblique anisotropy may be induced by the shape anisotropy connected with columnar grain morphology.

Effect of Geometric Arrangement on Agronomic Traits and Fibre Quality of Hirsutum Cotton

Effect of Geometric Arrangement on Agronomic Traits and Fibre Quality of Hirsutum Cotton

Simulation of impedance for 2-D composite

A computational methodology which utilizes the transfer matrix method was modified to simulate the a.c. transport properties of two-dimensional composites of triangular network. a.c. impedance spectra of macroscopic mixtures of hard spheres which have the random arrangement or regular form cluster of components were studied. It was shown that the impedance spectra of the two-components composite might show three arcs. The third semicircle was shown to originate from the isolated clusters, and to appear more distinctively when the elongated clusters were arranged along the preferred current flow line. Finally, it was emphasized that the effects of geometrical arrangement must be seriously considered in the analysis of the electrical properties of composite, especially when the filling fraction of composites was near the effective percolation threshold.

Computer simulation of the electrical conductivity of composites: the effect of geometrical arrangement

A computational methodology is presented to simulate d.c. and a.c. transport properties of two-dimensional composites. Using this method, average electrical properties, or, more specifically, d.c. conductivity and a.c. impedance spectra, of macroscopic mixtures of hard spheres which have random or regular arrangements of the components are studied. Numerical results are compared with the calculated results of analytic equations that have generally been used to describe the d.c. and a.c. electrical properties of composites. It is shown in this study that they are sensitive functions of the filling fraction, sample size and the geometrical arrangement of the components. The geometrical arrangement effects, which hardly can be considered in analytical formulae, become more important as the sample size decreases and the filling fraction approaches the effective percolation threshold.

Modelling the spread of fungal diseases using a nearest neighbour approach: effect of geometrical arrangement

A discrete model of the nearest neighbour type is used to model the growth and spread of fungal disease in a two‐cultivar mixture assuming an unspecialized pathogen. Disease dynamics and dispersal are represented by a spatial, single pathotype version of Gumpert's (1992) model that simulated the temporal evolution of a number of pathotypes on a cultivar mixture. Spore dispersal occurs by discrete rules between a cell and its four orthogonal neighbours in a rectangular grid. Parameters termed transmission efficiency rates control the extent of successful inoculum exchange between two neighbouring cells depending on the cultivars present. Spatially averaged disease progress curves are computed for regular block and strip patterns in addition to the mean curve for twenty 1:1 random mixture patterns. These sets of curves are exhibited relative to the appropriate pure stand comparison for a range of auto‐ and cross‐deposition parameters. We conducted simulations for uniform initial infection and also averaged over 20 random initial infection patterns at a comparable mean level. In the former case, provided the ratio of cross‐deposition to auto‐deposition is high enough and the disease progress curves take sufficiently long to reach their saturation value, the ranking of the geometrical patterns can eventually be interpreted once initial oscillations have subsided. The geometry with the largest proportion of links between neighbouring cells of different cultivar type generally corresponds to the lowest average disease level, but not for averaged simulations based on random initial infection patterns.

Effect of geometrical arrangement on experimental quantities in primary processes of photosynthesis

The effect of the number of antenna chlorophyll a molecules, their orientation and the dimensions of the reaction center on experimental quantities in a model of the antenna core based on the Pauli master equation is investigated. Results of numerical calculations, as well as analytic expressions for observables applicable from a few picoseconds after the excitation are given anddiscussed. The effect decreases with increasing time and from a few picoseconds it is very small.

Effect of geometrical arrangement and interdrop forces on coalescence time

AbstractAccording to the Reynolds' equation the time taken for a thin film to reach a critical thickness at which rupture occurs is a function of the film area and applied force. It follows that the coalescence time of a liquid drop is greatly affected by its geometrical configuration. If the drop is unconstrained the coalescence time increases when a vertical force is applied to the drop, but if the drop is constrained by the presence of surrounding drops its coalescence time decreases as the applied force increases. This explains why the rate of coalescence at the disengaging interface of a close‐packed dispersion increases with the dispersion height. The coalescence time for a planar film is usually less than for the spherical film formed between a drop and its homophase which explains why near‐horizontal surfaces inserted into close‐packed dispersion increase the rate of coalescence. The coalescence time of a drop in a close‐packed dispersion decreases as it approaches the disengaging interface. This means that the volume rate of coalescence at the interface may equal the disperse phase throughout without the necessity for interdrop coalescence. When the applied pressure is much greater than the van der Waals pressure, as in a close‐packed dispersion, the critical film thickness is itself a function of the film area and applied force, but this has little effect on the above conclusions. When the applied pressure is much less than the van der Waals pressure, as in a loose‐packed dispersion, the critical film thickness is only a function of the film area and the affect of the applied force on the coalescence time is then increased.