Applied Mechanics and Materials Vols. 754-755

Abstract: This project is to design an automated green sorting device that can be used to recognize, differentiate and separate between ferrous and non-ferrous materials, as well as to perform transferring of the mentioned materials. In particular, the technique of separation is using magnetic and Eddy-current concept. Eddy-current is generated on a conductor when the conductor is placed in a magnetic field. These Eddy-currents circulate such a way that they induce their own magnetic field and causing a repulsive force (Eddy force). The analysis done is to analyzed the maximum Eddy force generated to the non-ferrous materials when the materials coming close to the Eddy-current roller. The focused parameters in this analysis are a gap distance between magnet to magnet and a gap distance between magnet to material. The results show this sorting device is completely sort the mix materials (ferrous and non-ferrous materials) up to 90% of consistency.

Abstract: This paper presents the design technique of a compact composite microstrip filter operating at ultra high frequency (UHF) band and its fabrication using micro-electro mechanical system MEMS technology. The fringing compensation method is applied into the design of the microstrip line transformation from lumped element. The filter lumped circuits and microstrip line circuit were designed and simulated using Advanced Design Software (ADS) and fabricated on silicon substrates to obtain the best filter characteristic based on S-parameter. The measured and simulated results have achieved a good agreement within the frequency of interest. This shows that the fringing compensation method of transforming lumped element into microstrip line is able to solve the conventional design of complexity size of circuit of composite low pass filter (LPF) into microstrip line. The proposed filter design can replace the conventional filters in wireless communication as they offer better performance at lower cost in the RF microwave communication applications.

Abstract: The codoped ZnO thin film were deposited by DC magnetron sputtering on silicon (111) followed by annealing treatment at 200 °C and 600 °C for 1 hour in nitrogen and oxygen gas mixture. Structural investigation was carried out by scanning electron microscopy (SEM), atomic force microscopy and x-ray diffraction (XRD). Film roughness and grain shape were found to be correlated with the annealing temperatures.

Abstract: A systematic study of a series of Mo_xW_1-xS₂ layered mixed crystals, with 0 ≥ x ≤ 1, grown by the chemical vapor transport method were carried out by using Raman scattering measurements. The peaks of the two dominant first-order Raman-active modes, A_1g and E2g1 , and several second-order bands have been observed in the range of 150-500 cm^-1. The peaks corresponding to A_1g mode show one-mode type behavior while the peaks of E2g1 mode demonstrate two-mode type behavior for the entire series. The results can be explained on the basis of the atomic displacements for each mode. For A_1g mode only sulfur atoms vibrate and this give rise to a one-mode type behavior for the mixed crystals. For E2g1 mode metal atoms also vibrate as well as sulfur atoms, the mass difference of the vibrating Mo and W cations causes the two-mode type behavior of E2g1 mode. In addition, the observation of largest asymmetry and broadening of A_1g mode for Mo_0.5W_0.5S₂ has been attributed to random alloy scattering.

Abstract: This paper reports the mechanical analysis of bending test for Si and 3C-SiC materials. The analytical experimental were determined by using a standard three-point micro-bend test method (ASTM E290) to be applied on MEMS capacitive pressure sensor diaphragm. The MEMS device was fabricated into 5.0 mm x 5.0 mm square shape with the thicknesses of 680 μm and 1.0 μm thin film on 3C-SiC-on-Si wafer. The bending test is performed to determine the maximum stress during heat treatment up to 1000 °C and the load is applied until the 3C-SiC-on-Si wafer fracture. The test results indicated that 3C-SiC has good fatigue properties when heated up to 1000 °C with the maximum load of 52.72 N directly bring out the maximum stress and maximum strain of 104.95 MPa and 3.2%, respectively. This approach can be compared to Si, the material no longer withstand with the maximum load is 1.30 N only with the maximum stress is 10.13 MPa and maximum stain is 1.0%.

Abstract: A Roselle blend chitosan film sensor (RBFS) with different concentration of roselle has been developed. Electrochemical deposition has been chosen as an efficient technique for the fabrication of RBFS. RBFS with the concentration of 20cc of roselle has a stable value to detect the different concentration of fertilizer ranging from 0 ppm until 60 ppm. The type of fertilizer used in this testing was magnesium sulphate. The electrical laboratory testing result of the RBFS exposed to de-ionised water (DIW) showed the highest response with the value ~94%. The highest response value of RBFS exposed to magnesium sulphate with the concentration of 10 ppm was ~66%. The lowest response value of RBFS exposed to magnesium sulphate with the concentration of 60 ppm was ~30%. The results have been proven that RBFS is able to differentiate the concentration of fertilizer. The RBFS fulfils all the reliable sensing properties which include excellent response time, stability, repeatability, recovery, and selectivity. The morphological surfaces of RBFS were observed with SEM and chemical interactions between roselle blend chitosan were explained using FTIR spectra results. SEM image of RBFS showed the film surface was compact and the roselle was well distributed within the chitosan.

Abstract: Laser micromachining technique was used in this work to produce two different microfluidic structure on three MEMS materials namely silicon, SU-8 photoresist and polydimethylsiloxane (PDMS). The operational parameters of the machine ablation effects on the materials, which are the laser energy, laser pulse rate and the laser size were also investigated. We found that this technique is capable to produce typical MEMS structure similar as being produced using conventional photolithography process.

Abstract: The effect of different solution heat treatment temperature on the mechanical property and silicon morphology was investigated by hardness test and microstructural analysis. The samples of A319 alloy were solution heat treated at three different temperatures (495°C, 510°C and 525°C) followed by artificial ageing at 180^°C. The ageing kinetic was accelerated and peak aged gave the lowest value for the samples solution treated at the highest solution treatment temperature (525^°C). This result was due to the fragmentation and spherodization of the silicon particles morphologies in the microstructure of the samples.

Abstract: The consolidation of the painting layer or plane and carved gildings which represent different types of detachments is an essential operation for the preservation and restoration of the cultural goods of polychrome wood. Our paper focuses on testing a new type of acrylic binder applied on cracks with blind detachments with an OMRON nebulizer with NE-C28P compressor which sprays microparticles of 3 μm under a hermetic film that covers the operated surfaces. The experiments have been performed on samples of old gilded wood. The results are compared to those obtained by using the traditional process of peliculization of the acrylic binder over the detached surfaces and with the process of spraying. The analysis techniques used are the optical microscope and SEM-EDX.

Abstract: The paper presents a study about the structural modifications induced by heat treatment at the stainless steels, like AISI 321 and AISI 304, frequently used in industrial applications. The principal characteristic of these steels is their bigger corrosion resistance, conferred by chrome and nickel.The addiction of other elements is made for the improvement of corrosion resistance in humid environments (molybdenum and cooper), mechanical characteristics at low and high temperatures (tungsten, molybdenum, niobium and cobalt). The necessary condition to obtaining a high corrosion resistance is that all chrome content to be in forms of solid solution. The precipitation of carbides from solid solution causing a decrease under 12% of chrome content, the structure become bi-phase and the corrosion resistance decrease. For the improvement of machinability may be applied an annealing, with respect of all the treatment parameters, obtaining a micro-hardness decrease.The heating for annealing was made in an electric furnace, type UTTIS, with fixed hearth. The imposed heating speed was 10°C/minute. The decrease of micro-hardness by annealing, permit an easy processing for high alloy steels.