Papers by Keyword: Thin Layer

Abstract: In this research, smooth commercial Ti grade 2 corroded by ErCl₃.6H₂O under an electrochemical process with difference electrochemical current ranging from 0.5 – 4A, providing a rougher surface conducive to the adsorption on the Ti surface. A thin layer of TiO₂ nanotubes synthesized via the anodization method on microporous Ti surfaces for application in the biomedical field. The results reveal that the smooth titanium surface was completely corroded, resulting in the formation of a microporous structure, with a thin layer of TiO₂ successfully formed on the microporous titanium surfaces. The digital optical images obtained using digital microscope (VHX) showed that the micropore depth is around 41.94 - 55.83 µm. On the other hand, the SEM results revealed that the diameter of TiO₂ nanotubes ranged from 50 – 80 nm. The EDS and XRD techniques indicated that no impurities were present, and the TiO₂ phase was successfully formed. SEM images show positive results regarding the formation of a bone-like CaP mineral layer after 14 days of immersion in simulated body fluid (SBF), indicating suitability for biomedical applications.

Abstract: Usually, contact mechanics focus on semi-infinite solids, so that any interaction between normal and in-plane deformation is commonly disregarded. However, when dealing with layers of finite thickness, this assumption is no longer valid, and the specific geometry of the contact pair plays a key role in determining the normal-tangential coupling. In this study, we focus on the exemplar case of a thin deformable layer in frictional sliding contact with a rough profile, where the interplay between tangential friction and normal pressure may lead to significantly different contact behavior compared to the uncoupled case, both in terms of contact area size and frictional response.

Abstract: The tribological properties of commercially pure titanium need to be improved when applied as a friction component. This research investigated the effect of plasma nitrocarburizing process on the hardness and wear resistance of commercially pure titanium. The plasma nitrocarburizing process was carried out with a ratio of the composition of N₂ gas and CH₄ gas of 1:1, 1:2 and 1:3. Metallographic test by scanning electron microscopy was carried out to observe phase modifications on the surface of the material. Compounds formed in a thin layer on the surface of the commercially pure titanium were observed by X-Ray Diffraction testing. Furthermore, Vickers hardness and wear testing were carried out to determine the effect of the plasma nitrocarburizing process. The results showed an increase in hardness and wear resistance. The surface hardness of the untreated commercially pure titanium was 105.75 VHN and increased to 156.76, 211.12 and 236.32 VHN after the plasma nitrocarburizing process was carried out with a ratio of N₂ gas and CH₄ gas composition of 1:1, 1:2 and 1:3, respectively. The reduction in specific wear rate was experienced by commercially pure titanium. The specific wear rate of the untreated commercially pure titanium was 4.468E-8 mm²/kg. The plasma nitrocarburizing process, which was carried out with a ratio of N₂ gas and CH₄ gas composition of 1:1, 1:2 and 1:3, reduced the specific wear rate to 2.812E-8, 1.176E-8 and 6.14E-9 mm²/kg, respectively.

Abstract: The paper presents the results of the studies devoted to justification and development of methods and means of high-speed thin layer coating. It outlines the layer conditions formation, as well as the requirements for the individual components and surfacing installation assemblies. The following equipment items are designed and manufactured for the implementation of the developed coating processes: surfacing rack, feeding device rotating filler, surfacing head-die and others. The paper presents the completely temperature pattern detailed calculation program with differential-difference scheme-line obtained from a combination of explicit and implicit schemes. The mechanical properties, residual stress, fatigue strength, hardness and microstructure of the coating, etc. have been undertaken as well. The paper recommends the technology to restore worn surfaces of the cylindrical parts with little wear and tear (up to 0.3 mm) and to impart special physical and mechanical properties of the manufactured machine parts surfaces.

Abstract: Thin Hot Mixture Asphalt Concrete Overlays (THMACO’s) are comprised of a thin layer less than one inch hot mix asphalt concrete layer and a binder material/tack coat. The uses of thin layer are necessary to compromise with the environment issue especially to protect the natural resources and save the energy used during asphalt construction. THMACO’s can be used as preventative maintenance on pavement preservation or as a new surface on a pavementconstruction. This layeris usually regarded as non-structural layer at pavement design. However, this paper presents the structural assessment of this materials and their comparison to the conventional asphalt concrete mixtures. This research was conducted based on indirect tensile strength (ITS), unconfined compressive strength (UCS) and indirect tensile stiffness modulus (ITSM) of thin hot mixture asphalt. The results show that the thin hot mixture asphalt has performed slightly different on the Marshall and structural properties compare to conventional asphalt concrete.

Abstract: In the present the results of research of structure, phase composition and microhardness measurement of the surface layers of the Cr/Ti system treated by short-pulsed high intensity ion beams (HPIB) are presented. It was shown that the HPIB impact on a “coating/substrate” system can serve as an affective way to produce near-surface alloys in the metals. In particular, in the Cr/Ti system the formation of solid solution β-Ti (Cr) as well as titanium carbide TiC_x was revealed. The found changes in structure and phase composition of titanium caused by the HPIB impact allow to increase its microhardness in 2 times.

Abstract: Spectrum inversion method based on genetic algorithm (GA) is a kind of optimization methods for improving seismic data resolution, compared with the spectrum inversion based on conjugate gradient method,GA does not require a good starting model but rather a search space.In this paper, this algorithm is first proposed, and applied to thin layer identification,base on the resolution of odd and even component of reflection coefficient in thin layer,derive the spectrum inversion objective function, briefly describe the principle of genetic algorithm, finally in the wedge model and actual data for trial. According to the result, spectrum inversion method based on genetic algorithm can improve the ability of thin layer identification to a certain extent, improve the resolution of the seismic exploration.

Abstract: Fundamental Information on Drying and Re-Wetting Characteristics of Agricultural Seeds Is Required in the Design and Aeration Systems as Well as in the Prediction of Drying Rate Using Various Mathematical Models. Thin-Layer Drying Experiments Were Conducted Using Air-Ventilated Oven to Simulate the Artificial Drying at Various Moisture Contents of Sesame Seed (6.9 to 18.2 % W.b) at Three Drying Temperatures of 40, 50 and 60 ^OC. Five Drying Models Were Evaluated for the Thin-Layer Data. the Page Equation Fitted the Data Best, where Selection of the Best Model Was Obtained by Comparing the Coefficient of Determination (R2), the Standard Error of Moisture Content (SEM) and Mean Relative Percent Error (e) between the Experimental and Estimated Values. the Drying Rate of Sesame Seed under Drying Conditions Increased with Increased Temperature of Drying( 40 to 60 ^OC) and Initial Moisture Content of Seed( 6.9, 11.5 and 18.2 % W.b). the Parameters “K” of the Page Model Increased with Increase in Temperature, while, Parameter ”n” Decreased with Temperature Increase and Increased with Increase in Moisture Content of Seed. the Effective Diffusivity Was Found to Be 2.32 X 10-11 M²s-¹.

Abstract: In order to develop an electrochemical sensing system for bisphenol A, molecularly imprinted polymer (MIP) thin layers for bisphenol A were polymerized on a sputtered gold electrode by UV light irradiation for 2 – 30 min. Their thickness, which was determined by QCM analyzer, was 3.6 ±0.3 nm for 5min of irradiation and increased as the irradiation time increase to 30 min. AFM images of MIP modified surface suggested that the gold electrode was covered with MIP smooth layer. The responses to BPA and ascorbic acid of the gold electrode and MIP modified electrode were examined by cyclic voltammogram, and their anodic peaks were compared. The electrode with MIP polymerized for 5min showed more selective to BPA than that for 2min. This electrode can be served as BPA sensor and the anodic current of BPA depended on its concentration at the range of 5-15 μM.

Abstract: Imperfect transmission conditions modelling a thin reactive intermediate layer be- tween two bonded materials in a dissimilar strip are derived in this paper in most general case extending results obtained previously in [1]. The interphase material is assumed to be heat-resistant and situated in a thin rectangular domain between the main materials.