M.N. Berhan

Physical and mechanical characterizations of oil palm fruit bunch fiber filled polypropylene composites

Pulverized oil palm fruit bunch (OPFB) fiber was used as filler in Polypropylene (PP). Pulverized OPFB was added at various sizes (250 μm, 180 μm, 125 μm, and 100 μm) to study its effect on the physical and mechanical properties of OPFB filled PP. OPFB powder was mixed with polypropylene at 20 wt% and maleic anhydride polypropylene (MAPP) was also added as coupling agent at 2 wt%. Water absorption behavior of composites followed the normal trend where the water uptake increases with the increasing of OPFB size due to its hydrophilic characteristic. The incorporation of OPFB also decreases the thermal stability of composites at initial stage. Tensile and flexural properties were enhanced with the addition of OPFB powder and further increased with the increase of OPFB size. Meanwhile elongation at break and impact strength were decreased with the increase of OPFB size. SEM observation on the fracture surface of tensile, flexural, and impact tested samples provide further understanding on the effect of OPFB as filler in the matrix.

Effect of Low Impact Energy on Kenaf Composite and Kenaf/Fiberglass Hybrid Composite Laminates

Kenaf fibres recently have been a substitute material in many weight-critical applications such as aerospace, automotive and other industrial sectors. Their characteristics, such as low densities, specific strength and specific modulus are considered superior to those of metallic materials. The tensile and low velocity impact of kenaf composites and kenaf/fibreglass composites were investigated. The findings of such revealed that the tensile properties of the composites were seriously impaired even when low energy was used. As for hybrid composites, the tensile properties were hardly affected when tested with energy of below (6J). However, the tensile properties were reduced after the energy increased above (6J). Therefore, the impact damage of the composites can be predicted from measurements taken from the residual tensile strength of impacted specimens, and the damaged zones of the composites.

Structural Development of Expanded Austenite on Duplex Stainless Steel by Low Temperature Thermochemical Nitriding Process

This paper describes the results of gaseous thermochemical treatment of nitriding duplex stainless steel using tube furnace. The nitriding was performed in temperature range between 400°C and 500°C for 6 hours, forming a dual layer structure with hard nitrogen layer. The nitriding gas composition used for this process is 50% NH4 + 50% N2 and 25% NH4 + 75% N2. The structural development was characterised using hardness tester, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Based on the experimental results, it was found that nitrided layer produced maximum thickness nitrided layer about 13.96µm and hardness 666.3 HV0.025 at 450°C with 50% NH4. The formation of expanded austenite was observed in temperature range between 400°C and 500°C. However, the cromium nitride has been developed at temperature 500°C which decreased the corrosion properties of duplex stainless steel.

The Influence of Cyclic Load to the Properties of Weathered Granite

This paper briefly elaborates the influences of cyclic loading to the physical and dynamic properties of weathered granite. Petrological description of weathered rocks is also discusses as well as other important characteristics of rock which may affect the cyclic loads analysis. To find out the possible effect between weathered rock physical and dynamic properties with cyclic loading, weathered specimens are tested under same cyclical load condition of 1 Hz, stress ratio of 0.14 and using sinusoidal waveforms.

High Transparency Characteristics of Zinc Oxide Thin Films Annealed at Different Temperatures

Zinc Oxide thin film has been prepared by sol-gel spin-coating techniques and has three steps preparation were includes. They were solution preparation, thin film deposition and characterization process. The film were prepared to investigate the annealing temperatures depend with two environments were hot and room temperatures. Annealing temperatures were set up into five temperatures 200°C, 300°C, 400°C, 500°C, and 600°C were heated inside furnace. The characterization of ZnO thin film was measured by UV-Vis Spectrometry which to measure the transmittance of ZnO have when through the medium. The transmittance was investigated by use glass as a substrate. The optical properties showed when increased annealing temperatures, so the high UV was transmit. From that, the absorption coefficient of ZnO also can also investigate too. The surface morphology in increasing annealing temperature has a small size and less porosity between particles.

Quenching Heat Treatment Effects on the Mechanical and Microstructure Properties of AISI 304 Type Welded by GMAW Process Using Different Shielding Gases

As-received samples of an austenitic stainless steel AISI 304 type was welded by Gas metal arc welding (GMAW) robotic operation process using ER308L-Si filler metal wire. Two different atmospheres were used: 68% Argon plus 32% CO2, and 100% Argon. The aim of this study is investigates the influence of quenching heat treatment on the mechanical and microstructure properties of AISI 304 type which welded by GMAW under different shielding gas compositions. The fractured surfaces of the tensile test specimens examined using scanning electron microscopy (S.E.M). The results showed that the welding using shielding gas of 68% Argon plus 32% CO2 stronger than 100% Argon. After performed quenching heat treatment process, both specimens experienced a slight decreased in hardness.

Synthesis and Characterization of Zinc Oxide Nanostructured by Electrochemical Deposition Method

Zinc Oxide (ZnO) nanostructured was successfully synthesis by electrochemical deposition method. In this paper present the ZnO nanorods growth in a zinc nitrate/hexamethylenetetramine solution at 90°C with different potential applied. The effect of the growth process was investigated by the cyclic voltametric curve and the current-time curve. The structural of ZnO nanorods evidence that it has single crystalline, a wurtzite crystal structure with markedly preferential orientation along (001) direction was measured x-ray diffraction. The observation of ZnO nanorods was measured on field emission scanning electron microscopy that diameter of ZnO rods were below than 100 nm sizes. Uv-Vis spectrophotometer used to determine the transparency of ZnO nanorods through the UV light. The ZnO nanorods show the average transmittance (<90%) for all potential applied. The piezoelectric property of ZnO nanorods were measuring connected with two electrodes to the metal contact on the film that was driven by an ultrasonic wave. The piezoelectric output current was gained and characteristics curve have been illustrated for different voltage with constant driving frequency of ultrasonic wave at 40 kHz.

The Effects of Oil Palm Fruit Bunch (OPFB) Fiber and Coupling Agent Loadings on the Performance of Hybrid Composites

Hybrid composites were prepared by incorporating oil palm fruit bunch (OPFB) fibre in the mixture of clay and polypropylene as secondary filler. OPFB and MAPP loadings were varied to investigate it effects on the performance. Tensile and impact tests were performed on the hybrid composites to evaluate their mechanical performances. Water absorption and thermal degradation tests were also conducted on the hybrid composites. Results indicated that the incorporation of OPFB in PP/PPnanoclay has decreased the thermal stability of hybrid composites. Tensile modulus of hybrid composites increased as the OPFB loading increases and further increased with the increasing of MAPP loading. Generally the tensile strength has decreased with the addition of OPFB, however slight increased was observed when the MAPP loading was increased. The impact strength has also increased with the increasing of OPFB for higher MAPP loading.

THE EFFECTS OF OPFB SIZE ON THE MECHANICAL PROPERTIES OF OIL PALM FRUIT BUNCH FIBRE FILLED POLYPROPYLENE–CLAY NANOCOMPOSITES

Oil palm fruit bunch (OPFB) fibre was used as filler in polypropylene–clay nanocomposite (PNC) to study its effect on the mechanical properties of OPFB filled PNC or hybrid polymer nanocomposite (HPNC). The OPFB size was varied at 250 μm, 180 μm, 125 μm and 100 μm. HPNC was prepared by compounding 20 wt.% of OPFB together with PNC. Tensile, flexural and impact test samples were injection moulded from the compounds according to ASTM standards. The experimental results showed that the increase of OPFB size in HPNC has increased the tensile and flexural moduli from 39% to 54% and 33% to 69%, respectively. Meanwhile, the tensile and flexural strengths increased as the OPFB size increases. The elongation at break and impact resistance were not affected by OPFB size. Scanning electron microscope result showed that the fracture surfaces of coarser OPFB filled polypropylene–clay nanocomposite has several mechanisms such as fibre pull-outs, fibre fracture and fibre delamination, whereas the PNC filled with finer OPFB exhibited ductile fracture.

The Effect of Cyclic Stress on the Strain and Microstructure of Weathered Granite

This paper elaborates the effect of cyclic stress on tropically weathered granite of grade II, grade III, and grade IV. The specimens were tested under cyclic loading with frequency of 1 Hz, under constant sinusoidal waveform and identical stress ratio of 0.17. The test was setup under maximum stress of 70, 80, and 90 % of its ultimate strength. The compressional wave velocity, shear wave velocity, and uniaxial compressive strength were recorded before and after cyclic load testing in order to observe the post-cyclic effect on rock properties. Petrographic analysis using SEM and thin-section images were also captured to investigate the change in rock microstructure under cyclic load. Result reveals that when specimen is loaded at 70 and 80 % of its ultimate strength, eight out of nine specimens are able to withstand the one million cycles. However, at 90 % of the ultimate strength, only two out of nine specimens were failed before reaching one million cycles. SEM images were evidently showing the presence of abundance microcracks due to cyclic load.