Advanced Materials Research Vol. 974

Abstract: This paper presents the performance analysis of a LTE (Long Term Evaluation) band microstrip antenna printed on FR-4 substrate material. FR-4 substrate is a composite material of fiberglass cloth with flame resistive epoxy resin binder. It is a popular candidate for material selection in antenna design at higher bands. The proposed antenna contains a rectangular slot on the patch and covers the LTE band 7 (2.5 - 2.7 GHz). It is a cost effective approach to fabricate microstrip antenna for the LTE band 7 which is used in LTE technology throughout the world. The result shows a coverage bandwidth (<-6 dB) from 2.47 GHz – to 2.75 GHz and at 2.6 GHz the maximum achieved gain is 5.2 dB. The S-parameter is used as a comparison matrix for the simulated and fabricated antennas.

Abstract: This paper proposes the improvement of design and manufacturing of Falling Film Horizontal Tube Evaporators (FFHTE) through optimizing different parameters such as tubes pitch, tubes diameter and material and liquid film flow rate. These design and operational parameters have a significant influence on the hydrodynamic of the liquid film (eg: wetability of the tubes, scale deposition, heat transfer coefficient, etc.). Due to the complexity of the liquid film flow around the horizontal tube bundle, the experimental approach is preferred than modeling because it gives a better understanding of the phenomena occurring in the heat exchanger. In this paper one experiment was carried out to investigate liquid film flow around a single horizontal tube. A particular attention was taken for the measurement of liquid film thickness around the tube using a novel optical technique based on light reflection. The influence of the tubes pitch, tube diameter, height of the liquid distribution system and the liquid mass flow on the transitions between falling-film modes and film thickness is investigated and the results are compared to other data obtained from the literature. It was found that tubes wetability and heat transfer increased with increasing the vertical tube pitch. To account for fouling and heat transfer performance, a tube spacing value of 1.3 was recommended.

Abstract: The paper presents a study on the development of an analysis procedure for determining of gold coating thickness using the EDXRF technique. Gold coating thickness was measured by relating the counts under the Au Lα peak to its thickness value. In order to get a reasonably accurate result, a calibration graph was plotted using five gold-coated reference standards of different thicknesses. The calibration graph shows a straight line for thin coating measurement until 0.9μm. Beyond this point, the relationship was exponential and this may be resulted from the self-absorption effect. Quantitative analysis was then performed on three different samples namely two gold-coated jewelry samples and a phone connector sample. Result from the phone connector analysis seems to agree with the manufacturer’s gold coating value. Results from the analysis of gold-coated jewelry enable to differentiate the two articles as coated by using the gold wash and gold electroplated coating methods.

Abstract: This paper aims to study the effect of using Oxidized White Liquor (OWL) on pulp brightness in peroxide bleaching. The proper setting of the concentration of hydrogen peroxide, the bleaching temperature, and the bleaching time was also studied. The Central Composite Design (CCD) was proposed to generate necessary experimental runs. Regression analysis was used to determine the relationship equation. Optimization helped determine that to obtain the targeted brightness of 83%, the ratio between the volume of OWL and sodium hydroxide should be 50:50. This ratio should be used with a concentration of hydrogen peroxide at 6.9 g/kg, a bleaching temperature of 90 ^oC and a bleaching time of 75 minutes.

Abstract: Nanotechnology provides the opportunity for the development of new materials in the nanometer size range with many potential applications in biological sciences and clinical medicine. RD (muscle cancer cell line) was seeded out in 25 cm² plastic tissue culture flasks (NuncWiesbaden Germany) individually, in Minimum Essential Medium (MEM) with Hanks salts, containing 10% fetal bovine serum (FBS) and 2 mM L-Glutamine along with some nonessential amino acids and were incubated for 24 h for proper attachment to the substratum and kept at a 96 wells plate, incubated at 37°C and 5% CO₂. SEM was employed to the nanoparticles and size of α-Fe₂O₃ and SiO₂ nanoparticles were about 66 nm and 250 nm. Moreover 10-80μg/mL of Hematite (α-Fe₂O₃) and SiO₂ nanoparticles dispersed solution were labeled for each row of 96 wells plate. The present study evaluates the different parameters, e.g. time of incubation, cytotoxicity and cellular viability of the Human Rhabdomyosarcoma cell line (RD) as an experimental model. The viability of cells was determined by means of neutral red assay (NRA) after the cell-exposition to different concentrations of Hematite (α-Fe₂O₃) and SiO₂ nanoparticles into mentioned tumoricidal cells

Abstract: The ability of mixed enzyme (ɑ-amylase and cellulase) immobilized via cross-linking method with 3% of glutaraldehyde (GA) on polymeric membrane containing 20 wt% of polysulphone and 80 wt% of 1-methyl-2-pyrrolidone (NMP)/polyvinylpyrrolidone (PVP) to catalyze the complex structure (starch and cellulose) into glucose was investigated in this study. Central Composite Face Centered Design (CCFD) with alpha equal to 1 (ɑ=1) were used to evaluate the effects of pH, temperature, percent of enzyme dosage and percent of substrate concentration on enzymatic hydrolysis process. Maximum glucose concentration (g/L) was obtained at 50°C, pH 6.5, 3% of enzyme dosage and 3% of substrate concentration. The study indicated that only substrate and enzyme ratio play significant role (P < 0.1) in maximizing glucose production within pH, temperature, substrate and enzyme dosage range of pH5-8, 30-70°C, 1-5w/v%, and 1-5w/v% respectively. Kinetic enzyme using Lineweaver-Burk plotting suggested that Km and Vmax for the mixed enzyme in this process were 9.6 g/L and 0.3571 U/mg respectively.

Abstract: Rheological factor such as shear rate during membrane fabrication process has an effect on structural properties and performance of membranes. Flat sheet asymmetric polysulfone/cellulose acetate phthalate/polyvinylpyrrolidone (PSf/CAP/PVP) blend membranes were prepared by using an automatic casting machine at different shear rates in the range of 42.0 to 210.0 s^-1. The blend membranes prepared at different shear rate were characterized in terms of its structural properties (molecular weight cut-off (MWCO) and average pore size) and performance (proteins separation). The results showed that increasing the shear rate from 42.0 to105 s^-1 has decreased MWCO and average pore size of the blend membranes which then reduced protein solution permeate fluxes and increased proteins rejection of PSf/CAP/PVP blend membranes. However, further increasing the shear rate to 210.0 s^-1 has resulted in an increase in MWCO and average pore size and consequently increased protein solution permeate flux but decreased proteins rejection.

Abstract: Waste cooking oil has proven to be a problematic material in the developed countries since people usually pour waste cooking oil into the kitchen drainage because they unaware that this waste can be recycled. Thus, in this study, the converted waste cooking oil into polymer was fabricated by using hot compression machine and named as waste biopolymer (WB). Vibration transmissibility test was conducted to determine the WB characteristics before and after UV-irradiated. It is revealed the similar vibration transmissibility responses curves were obtained at 1mm, 0.1g and 0.15g base excitation levels for the entire testing frequency except for the displacement transmissibility from base to moveable top plate at 1.5 mm. There was only one resonance peak occurred over the testing frequency which was 15 - 23 Hz for the displacement transmissibility and 15 – 25 Hz for the acceleration transmissibility test on shaking table. No other variation used on the displacement and acceleration amplitude to control the transmissibility test of UV-irradiated WB system based on shaking table. Evidently, small changes on the frequency of the vibration transmissibility were shifted to higher value of UV-irradiated WB with overall percentages of changes are below 5% except for displacement transmissibility at 1.5 mm. This shows the photo-stability of WB after UV-irradiation is high and could be used for further study.

Abstract: In the developed countries, waste cooking oil has proven to be a problematic material since people usually pour waste cooking oil into the kitchen drainage because they unaware that this waste can be recycled. In this study, the waste cooking oil was converted into polymer, fabricated by using hot compression machine and named as waste biopolymer (WB). WB characteristics before and after UV-irradiated such as vibration damping, density and surface morphology were analysed in this study. Total damping ratio of WB changes more than 5% after 1000 hour UV-irradiation. UV-irradiation does not give major influence to the WB morphology since there is no big change for overall structure of UV-irradiated WB after 1000 hours of UV. Even though the density of UV-irradiated WB is decreasing with increasing exposure time to UV, but it gives good influence to the damping ratio. WB is expected to have a good service life even in a harsh UV environment thus it can be applied in many applications especially in automotive field and manufacturing packaging.

Abstract: The study of physicochemical properties of solid catalyst such as particle size, surface area and basicity are significant today since their reactivity depend on these properties. The number of defect sites in CaO, an alkaline metal oxide is important in heterogeneous catalysis. In this research work, nanostructured CaO was synthesized from commercial CaO via hydration-dehydration method. The surface modified CaO was calcined at various temperatures from 300°C to 800°C respectively under vacuum atmosphere of 10^-3mbar. The prepared nanostructured CaO was then characterized using Thermogravimetric Analysis (TGA) and Fourier Transform Infrared (FTIR). The basicity then determined by back titration method. This research found that when activation temperature increased, the basicity also increases. For optimization, the prepared nanostructured CaO-600 was selected and applied for base transesterification reaction using algae species, Kappaphycus alvarezii to produce biodiesel. The latter reaction was then confirmed by Nuclear Magnetic Resonance (NMR) spectroscopy.