Papers by Keyword: Interfacial Layer

Abstract: Basalt plastic, thanks to its complex of valuable operational properties, has a potential variety of applications. the article describes the technology of production of basalt plastics with various types of hybrid matrices, one of the components of which is cured in the molding process, and the second-like a binder in natural materials, retains its viscoelastic state. The viscoelastic component makes it possible to increase the deformation properties in the zones of their location, preventing cracking under increased loads. As a result of the conducted mechanical tensile tests, the average values of absolute breaking forces, tensile strength and elongation during fracture of basalt plastic samples with different types of hybrid matrices were obtained. The addition of viscoelastic components (such as technical wax, anaerobic, and organosilicon polymer materials) to the basalt plastic matrix allows to increase the elongation at fracture by 2...5%. Anaerobic polymer material in the basalt plastic matrix allows to increase the tensile strength of the composite material, as well as significantly reduce the dispersion of the measured values. This provides an effective prediction of the operational properties of the structural material in the design of products. On the basis of microanalysis of the structure of basalt plastics with different types of hybrid matrices, an explanation of the causes of changes in the mechanical properties of the resulting composite materials is given.

Abstract: Impurities and resulting inclusions are an issue when processing higher amounts of scrap during steel making. To increase the recycling rate, the removal of impurities from the scrap in form of inclusions is of great interest. In previous studies was found that inclusions attach primarily on carbon containing refractories, especially if on their surface an interfacial layer (1–3 µm thickness) was formed in-situ. This study investigates the formation mechanism of this in-situ layer in detail by application of computer tomography (CT) measurements on two scales. The large scale CT scans visualized the general appearance whereas the small scale measurement regarded the in-situ formed layer and the attached inclusions in detail. Based on these measurements, previous results and a literature review it was concluded that the layer formed mainly due to carbothermally reduced impurities which moved to the decarburized surface of the refractory in gaseous form and enhanced sintering of the surface region to develop the layer.

Abstract: A new numerical method for homogenization of elastic properties of dispersedly-reinforced composites was presented. The method takes into account special model of adhesive contact. Homogenization of properties was performed by averaging the solutions of boundary value problems on representative volume cell (RVC) using the finite element method (FEM). A new approach of calculation of components of effective tensor of elastic moduli was proposed. A heterogeneous finite element model with elements of two types was built: three-dimensional tetrahedron elements for every phases and spring element with zero-length for adhesion layer with zero-thickness. The results of homogenization of elastic properties of dispersedly-reinforced composites with variable stiffness of the adhesive layer between phases were obtained and analyzed. The homogenization results were compared with the available experimental data.

Abstract: This paper explored the effects of pressure on contacts between layers of organic photovoltaic cells with poly (3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT:PCBM) as the active layer. The contacts between the layers are modeled using analytical concepts and finite element models. The potential effects of surface roughness and dust particles are modeled along with the effects of lamination pressure and adhesion energy. The results show that, increased pressure is associated with decreased void length or increased contact length. The contacts associated with the interfaces between the active layer and the hole/electron injection layer poly (3,4-ethylenedioxythiophene: poly styrenesulphonate (PEDOT.PSS) and Molybdenum trioxide (MoO₃) are also compared. The implications of the results are discussed for the design of stamping/lamination processes for the fabrication of organic photovoltaic cells.

Abstract: Energy production and storage are both issues with increasing demands for improved performance and the requirement for greener energy resources constitute immense research interest. Graphene, (Gr) has incurred intense interest since its free standing form was isolated in 2004. Gr has immense potential to be used for low-cost, flexible, and highly efficient organic solar cells (OSC) due to its excellent electron-transport properties and extremely high carrier mobility. Numerous Gr-based OSC have been reported, in which Gr serves as different parts of the cell. One of the reasons for the current interest in Gr is the great potential for transparent conductive electrode (i.e. anode or cathode) in OSC. Gr is an ideal two-dimensional material which can be assembled into film electrodes with good transparency, high conductivity, and low roughness. Besides the potential to act as a transparent conductive electrode, Gr also has other attractive properties for solar devices. For example, Gr has been incorporated into photo-active conjugated polymers to improve the excitons (e^-/h⁺ pairs) dissociation and the charge-transport properties of the materials. Additionally, Gr also has potential to be used as an interfacial photo-active layer, since its band gap and band-position can be induced and tuned via chemical functionalization or by controlling the size of the Gr sheets. Although Gr is still a relatively new material it has already made a wide and diverse impact and this review will enlighten us towards using Gr as a novel material for future energy storage/generation applications.

Abstract: The Interfacial layer has an important influence on the optical performance of the deep ultraviolet (DUV) coatings. The variable angle Spectroscopic ellipsometry measurements of three kinds of DUV coating samples were performed in the wavelength range 150-500nm using a purged variable angle Spectroscopic ellipsometer. The samples include the single layer sample, double layers sample, and three layers sample. The thickness and optical index of the MgF2 layer and LaF3 layer as well as those of the interfacial layer between them were obtained by successful regression of the SE measurements. For the single layer, the agreement of the results between the SE and the spectrophotometic techniques was very good. The obtained thickness of the two kinds of interfacial layer was in consistent with the RMS results of the single layer obtained by AFM, indicating the obtained results were reliable.

Abstract: Various mechanisms and correlations have been developed for prediction of thermal conductivity of nano-suspensions. However, seldom theoretical researches on thermal conductivity of nanofluids containing surfactant are found. In this work, a thermal conductivity prediction-model of nanofluid containing surfactants is proposed based on Leong et al.’s model and Langmuir adsorption theory by considering the interfacial surfactant layers. The thickness of the interfacial layer is defined by Langmuir adsorption theory. Compared with the experimental data available in the literature on thermal conductivity of nanofluid containing surfactants, the calculated values on the proposed model have been verified that the proposed models show reasonably good agreement with the experimental results and give better predictions for the effective thermal conductivity of nanofluids compared to existing classical models.

Abstract: We have performed a combined investigation of experiment and theory on the infrared reflectance from cubic SiC grown on Si by chemical vapor deposition. A damping behavior of the interference fringes away from the reststrahlen band and a dip or notch within the “flat top” are observed from some samples while they does not occur in high quality 3C-SiC/Si samples. The former is interpreted due to an interfacial transition layer existed between SiC-Si and a rough surface, while the latter can be demonstrated by a three-component effective medium model.

Abstract: Amorphous carbon coatings for implantable medical devices require high mechanical strength, adhesion and uniform biocompatibility response across the devices. Investigation of a-C:H properties and structure variation with thickness and substrate material provides valuable insight into requirements for device coating. A number of devices are coated and the effect of interfacial layers, film doping and the spatial variation in quality is investigated.

Abstract: Pure aluminum ingot (99.8 wt%) was melted to prepared chilled samples in this study. These samples were then removed to polish their surfaces and put in an ultrasonic cleaner filled with tap water. The polished surface would gradually show foggy marks after being subjected to a period of treating time. Oxide films, if entrapped, would crack, erode and detach from the chilled sample forming foggy marks on the polished surface. The sample then removed to measure oxygen and aluminum concentrations varied along the transition layer between the oxide film and aluminum matrix. Part of chilled samples was melted in a muffle furnace and subjected to different holding time. As the holding time increased, the transition layer between the oxide film and the matrix was increased and composed of different constituents varying from the Al matrix to the oxide film (mainly γ-Al2O3). This transition layer also showed different hardness measured by a nano-hardness tester. The morphologies of cracked oxide film and the eroded oxide particles were affected by the holding time after melted, and small amounts of silicon in the pure aluminum.