Advanced Materials Research Vol. 1087

Abstract: Measurement of peak voltage of Philips Industrial X-ray Machine is essential to be carried out at least at annual basis to ensure the accuracy of tube voltage applied in determination of standard radiation qualities for calibrating diagnostic dosemeter. In this paper, the peak voltages for dial voltages range within 40kV to 160kV were measured using Amptek spectrometer system. All X-ray spectrums produced from the X-ray tube were calibrated against standard calibration spectrum that was established using two standard sources: ⁵⁵Fe and ⁵⁷Co. The peak voltage for each dial voltage was determined based on the end point energy of the X-ray spectrum. The percentage deviation of measured peak voltage relative to dial voltage was calculated. The results from measurement in 2008 to 2013 demonstrate that all peak voltages from 40kV to 160kV tube potentials are within the tolerance limit of ± 5%. These results complies the recommendation by the International Electrotechnical Commission (IEC) 61676. As a conclusion, regular checks of peak voltage should be performed to ensure consistency of voltage applied to the X-ray tube thus maintain the accuracy of standard radiation qualities produced from the X-ray tube.

Abstract: The focus of this study is to investigate the mechanical properties and fracture behaviour of polydimethylsiloxane filled crystalline silica composites (PDMS/CS) upon tensile loading. The PDMS/CS composites were fabricated by using casting method and cured at room temperature for 24 hours. Crystalline silica (CS) were added to PDMS at compositions of 2, 6, 10 wt%. The tensile properties of PDMS/2wt%CS showed that the tensile stress were improved by 4.3%. Fracture behaviour as determined by the characteristic of fracture surface of pure PDMS and PDMS/CS composites were analysed using Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM). Observation via FESEM and AFM indicated different fracture characteristic of filled PDMS and unfilled PDMS. The addition of CS as fillers were indeed proven to improve the strength of the composites.

Abstract:

This paper presents numerically the empty tube response subjected to oblique loading. According to literature survey, there have large number of works discuss on the crushing performance when subjected to axial loading. However, lack of work available on the crushing behaviour under oblique loading. Therefore, this work presents the numerical studies on the crushing behavior of empty tube subjected to oblique loading. ANSYS Finite element program was used to model and solve the problem. The developed model was firstly validated with the previous result and it is found that the results obtained were acceptable. There were two important parameters were used such as tube geometry and oblique loading. According to the present results, when oblique angles were increased, the crushing performance decreased. However, when the elliptical ratios were increased, the energy capabilities increased.

Abstract: This present paper describes numerically the tube responses subjected to eccentric loading using ANSYS finite element program. According to literature review, tremendous amount of works available on discussing the axial crushing of empty tube under axial loading. However, lack of work related with the crashworthiness aspect of tube crushing under eccentric loading was identified. Therefore, the eccentric compressive loading on the empty tubes were focused. There have important parameters were studied such as the eccentric loading. According to the present result, the behaviour of crashworthiness expected to increase when the increment of eccentric loading was introduced. The crashworthiness behaviour and energy absorption capabilities demonstrated efficiently by the collected data mean crushing force and peak crashing force.

Abstract: This research aims to determine the effect of silver nanoparticles concentrations as antimicrobial coatings when doped to TiO₂ coatings. The TiO₂ coatings were prepared by sol–gel method initiating Titanium Isopropoxide–Propanol mixture as a precursor solution. The silver nanoparticles (40 nm) were then doped to the coating after sintering at 500°C. Two concentrations of silver nanoparticles, (50 ppm and 1000 ppm), were prepared for comparison in this study. Microstructure and crystalline phase of coatings were evaluated using Scanning Electron Microscope (SEM) and Glancing Angle X-Ray Difraction (GAXRD) technique. The antibacterial test was according to McFarland standard for detecting E.Coli, S.Aerues, fungas and Methicillin-Resistant Staphylococcus Aureus (MRSA). Results show that only coatings with the concentrations of 1000 ppm of silver nanoparticle function as antimicrobial coatings.

Abstract: A selective hydrogenolysis of glycerol has been attempted using an active nanosize and bulk size of Ru/FTO catalyst. The two approaches gives 1,2-propanediol as a main product. The higher conversion and selectivity was obtained at 99% and 94% for the bulky size of the catalyst, while nanosize catalyst give 89% of glycerol conversion and 97% 1,2-PDO selectivity. The Ru/FTO (7.5%) of metal loading, 150°C, 20 bar hydrogen pressure, and 8h was observed as an optimized reaction condition.

Abstract: Hydroxyapatite (HAp), classified as bioceramic materials is the major mineral constituent of vertebrate bones and teeth. In this study, the effect of temperature on isolation and characterization of HAp from tilapia fish scales have been investigated. Scales were subjected to heat treatment at different temperatures (800°C and 1000°C) and microstructure of both raw and calcined scales were observed under Scanning Electron Microscopy (SEM). Thermo Gravimetric Analysis (TGA) and Energy Dispersive X-Ray Spectroscopy (EDX) results have revealed the best calcination temperature of tilapia scales to be 800°C due to the calculated calcium to phosphorous weight ratio (Ca/P). The Ca/P ratio for scales treated at 800°C and 1000°C were 1.598 and 1.939 respectively. The phase purity and crystallinity of produced HAp was further confirmed by X-Ray Diffraction (XRD) analysis. Based on the study, it can be concluded that tilapia fish scale is a good natural source of HAp with 800°C as the optimum calcination temperature in HAp production.

Abstract: Cellulosic material derived from Merbau (Intsia bijuga) was extracted at atmospheric pressure. In the initial stage the sample was delignified using peroxyacetic acid to remove the amorphous. In the second stage the samples were double bleached using hydrogen peroxide (H₂O₂) and sodium Hydroxide (NaOH). From the X-Ray Diffraction (XRD) data it is evident that both acid and alkali bleached celluloses have rich cellulose I structure. The results are supported by FTIR study in which all samples shown typical spectra of cellulose.

Abstract: Cellulose is one of the most abundant biomass material in nature extracted from natural fibers. Its hierarchical structure allows different kinds of microfibril cellulosic fillers to be obtained known as cellulose microfibril or microfibrillated cellulose (MFC). MFC is generally prepared by either acid hydrolysis, or chemical treatments, or by a high pressure refiner. In this study, attempts have been made to extract MFC from Resak’s hardwood waste (Vatica spp.) at atmospheric pressure using single-stage peroxyacetic acid delignification and Totally Chlorine-Free bleaching methods. The morphology structure of samples were characterized using Field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD).