Applied Mechanics and Materials Vols. 754-755

Abstract: The current paper first analyzed the degradation mechanisms of the worn disc cutter made of forged H13 chromium alloy for hard rock tunneling applications. The paper investigated subsequently the mechanical properties of H13 to have a better understanding of the degradation mechanisms. Hardness tests were carried out on different positions on a cutter. Tensile tests and fracture toughness were carried out to investigate temperature effects. The test results showed that the material has a high wear resistance and a good temperature resistance, but its quasi brittle behavior and the residual stress effect (due to the cutting process) is critical for the chipping damage of the disc cutter.

Abstract: We investigated into report a study biosensor based on silicon into an effect on the dimensions of conductance design and simulation nanowire surface with molecular DNA for sensitivity. In the design nanowire of A biosensor with 3 layers starting with polyisilicon nanowire of radius 8 NM surrounded by a 50-nm electrode layer, and the substrate by a 300nm. COMSOL Multiphysics software used to provide interaction with molecules such as DNA and the distribution of the electrostatic potential in the narrower due to the dimensions, surface nanowire charge was computed using Poisson equation with Boltzmann statistics. In the result of the effect geometry was also studied and the different dimension yield different space charge and the surface charge at interactive site were also investigated and the study demonstrate steps wise identification of all critical parameters for (DNA) attachment with surface nanowires.

Abstract: One of the characteristics of longitudinal development of extensive air showers is the number of charged particles and depth of shower maximum in extensive air showers as a function of primary energy, which is often used to reconstruct the elemental composition of primary cosmic rays. Studying of extensive air shower characteristics was performed by investigating the longitudinal development parameters depending on Heitler model for different primary particles. The simulation of the number of charged particles and depth of shower maximum (N and X_max) in extensive air showers of particle cascades was performed using AIRES code for SIBYLL hadronic model for different primary particles like electron, positron, gamma quanta and iron nuclei at the energy range 10¹⁴-10¹⁹ eV. The comparison between the simulated longitudinal development of N and X_max using SIBYLL hadronic model with two hadronic models (QGSJET99 ans SIBYLL16) has shown an opportunity for determination of cosmic ray cascade interactions in extensive air showers.

Abstract: Arc spraying (AS) is a thermal spraying method. The spraying distance represents one of the main technological parameters. EDAX analysis, performed on the sprayed layers (SDA and SDS), have shown differences between the initial chemical composition of the filler material and of the obtained layers. The quantitative variations determined for Ni, Fe and Cr can be explained by: the volatilization process of the chemical elements from the electric arc area; losses increase with increasing the length of the spraying jet.

Abstract: Different compositions of carbon molecular sieve (CMS) were incorporated in polyethersulfone (PES) matrix to fabricate mixed matrix membranes (MMMs) by solution casting method. The characterization was carried out using field emission scanning electron microscopy (FESEM) analysis to investigate the morphology of membrane. FESEM images showed acceptable contacts between the filler particles and the polymer chains. The performance of the developed membrane is analyzed by single gas permeation measurement of high purity CO₂ and CH₄. Both CO₂ permeance and CO₂/CH₄ selectivity increased with CMS loadings as compared to pure PES membrane. Experimental results showed that the highest value of CO₂ permeance (66.71 GPU) and CO₂/CH₄ selectivity (10.94) can be achieved with 30 wt. % loading of CMS particles. This can be credited to size discrimination of CMS pores that falls between CO₂ and CH₄ kinetic diameters.

Abstract: This paper discussed on damage area and non-destructive testing on Glass Fibre Reinforced Polymer (GFRP) after low velocity impact event using drop weight impact tester. Specimens from C-type and E-type fibreglass fabricated in 10 layers with size 150 mm x 100 mm, were subjected to low-velocity impact with circular steel impactor at various energy levels from 10 J to 40 J. Visual observation techniques using a lab microscope were used to determine the damage visual by looking at the crack. Dye penetrants were used to inspect the area of damage and to evaluate the internal and external damage on the specimens after impact. The results from the experiment were discussed and presented.

Abstract: A series of high refractive index of α,ω-vinyl silyl terminated polydimethylsiloxane-co-polydiphenylsiloxane was synthesized by the equilibration ring opening – anionic polymerization of cyclic organo-siloxane oligomers in the present of 1,3-divinyltetramethyldisiloxane as terminating agent. Structural modifications were characterized by use of FTIR, H-NMR, and solution viscosity. UV-visible spectroscopy was analyzed which reveal a good transmittance in the region 400 – 750 nm radiation for all polysiloxanes.The presence of diphenylsiloxane unit results in a linear increase of the refractive index of the resin. These features favor good application as encapsulant for high brightness LED (HBLED) packaging.

Abstract: Liquid and plastic limits are very important especially for classification of soil and other engineering purposes where they can provide basis information and also better understanding about the soil. In this study, the geopolymerization process was applied to three different soils; kaolin and the other two soils (Soil 2 and Soil 3) were taken at two different places to investigate any changes of liquid and plastic limit values with solid (soil) to alkaline activator (S/L) ratio range from 1 to 4. The results obtained indicated that the geopolymerization process influenced those values and with further investigation, there might be possibility the properties of soil could be improved due to the chemical reactions.

Abstract: This paper presents an experimental study on corrosion of carbon steel as reinforcement bar in artificial solution of geopolymer paste by Open Circuit Potential (OCP). The OCP measurements have been used in reinforcement bar concrete studies for many years to determine the corrosion behavior of materials. OCP is the potential of the working electrode relative to the reference electrode when no current or potential is being applied to cell. The OCP of reinforcement bar was recorded with time and this experiment has been done for 30 days. A copper/copper sulfate (Cu/CuSO₄) reference electrode with a potential V-SHE of +0.318 V (at 25oC) was used in this study. The pH of geopolymer concrete was observed to be in the range of 11.5 to 12.5 depending on the formulations. Thus, in this study the artificial solutions of geopolymer paste that were used are pH 11, pH 12 and pH 13. It has been found that the potential values of three solutions were fluctuated from the beginning until day 30. The highest potential value was indicated by pH 13 whereas the maximum value is 0.542 V and minimum value is 0.205 V while pH 11 shows the lowest potential value with the maximum value 0.356 V and the minimum value-0.047 V. However, all the redox potential values for pH 11, pH 12 and pH 13 were located at passivity region, Fe₂O₃. The Fe₂O₃ is the stable phase in which this oxide acts as a protective film or passive layer in this region. It would be expected to provide some protection against corrosion. Keywords: corrosion, artificial solution, geopolymer paste, reinforcement bar, open circuit potential, passivity

Abstract: An attenuation relationship for far field earthquakes considered by strike slip has been developed. The attenuation relationship function was develop using regression analysis. The database consisting of more than 130 peak ground accelerations from seven earthquake sources recorded by Seismology Station in Malaysia have been used to develop the relationship. This study aims to investigate the new relationship attenuation to gain exact peak ground acceleration at the location on site. Based on this study, the location is a structure located at Terengganu seaside.