Papers by Keyword: Screening Effect

Abstract: Swirling Fluidized Bed Polishing (SFBP) is a non–traditional alternative abrasive flow surface finishing form of Fluidized Bed Machining (FBM) in which the former has special features to overcome certain significant limitations of the latter, namely the variation of the surface roughness vertically along the component surface and the screening effect owing to the complex contours in the work piece geometry. Owing to its ability to perform machining and generate polished surface from a roughness value of Ra 1.2μ to 0.2 μ within 8 hours of processing, this new method offers greater scope in the surface modification of rough machined surfaces with complex geometry such as component with ducts and grooves. This research focus on investigating the effect of abrasive particle concentration on metal removal rate per unit area of the specimen surface. 3D surface morphology analysis investigates the quality of the polished surface and the study of circumferential uniformity and machining accuracy analysis on a complex-contoured component further investigate its scope and relevance in industrial applications.

Abstract: Although the effect of phosphate on photocatalytic activity of TiO₂ is extensively investigated, its effect on the photoelectrocatalytic activity of TiO₂ electrode is not clear. The effect of phosphate on photoelectrocatalytic oxidation of water and organics on the TiO₂ electrode were investigated in this study. Phosphate has a sophisticated influence on the photoelectrocatalytic oxidation of water on TiO₂ electrode. The photoelectrocatalytic oxidation of water was inhibited at the low phosphate concentration (<5 μM) while improved at the high concentration. However, phosphate has an adverse influence on the photoelectrocatalytic oxidation of whether the strong or not the weak adsorption organics on the TiO₂ electrode, which is different from its effect on photocatalytic process of organics on the TiO₂ slurry, in which the photocatalytic oxidation of the weak adsorption organics is enhanced. However, phosphate can improve the linear concentration range of organics, especially strong adsorption organics (e.g. KHP, 0-333 μM for without phosphate to 0-500 μM for the with 1 M phosphate). Moreover, it is unanimously consent that phosphate has a very strong acid-base buffer capacity. These properties provide an excellent potential for phosphate application during the detection of practical samples, especially the acid and/or base samples.

Abstract: With the rapid development of industry and transportation, the awareness of environmental problems such as noise pollution and vibration pollution and so on, has led to an increasing interest in methods for noise and vibration isolation. The dynamic mechanical model for forging hammer foundation is analyzed firstly. Through the choice of the scheme of vibration isolation, one vibration isolation trench coupling the piles in rows was design. Grouting piles used as exterior protected structure for vibration isolation trench, which have a role of rigid vibration isolation. Soft material in-filled in the trench, which has a function of flexible isolation, can absorb the residual vibration energy penetrating through the piles in rows. It indicated by the site measurements that the surface waves should be hold back and diffracted effectively by the coupling effect of flexible isolation of the in-filled material and the rigid isolation of piles in rows.

Abstract: In this paper the electric field simulation of carbon nanotubes triode field emission devices is investigated. The geometry of CNTs and their arrangement on the substrate affect the screening effect and filed enhancement factor (β). In an array of nanotubes, for a distance smaller than the CNT length the screening effect is observed. The emission current density is related to the gate aperture and CNT shape. In a triode structure the screening effect occurs in the intertube distances about half of the CNT’s length due to the presence of the gate plate. Furthermore, the presence of the metal-oxide gate has a favorable effect to minimize the screening effect and allows one to increase the density of CNT’s in each array spot and to increase the cluster array density on the substrate, hence to increase the density of emission current and emitter sites where a high current density is required.