Advanced Materials Research Vol. 856

Abstract: In this study, surface characteristics of the samples of experimentally manufactured woodplastic composites (WPC) were determined. Turning process was used to produce surfaces by removing material from a rotating workpiece. For turning, the rotation speed, feed, and depth of cut determine the rate of material removal and resulting surface quality. The surface roughness is one of the most important factor affecting coating performance of the WPCs. Parameters of surface roughness (final micro-geometric characteristics Ra, Rz) of the samples was determined using a stylus-type profilometer Surftest SJ 401. This information will provide baseline data on the quality of WPC samples after turning.

Abstract: In this study, sulfur and sulfur wastes from petroleum refinery were utilized to produce sulfur concrete. Sulfur concrete was prepared by mixing molten sulfur and modified sulfur. Then, filler and sand was added and mixed continuously. This research was investigated by assessing the effect of ratio and sulfur wastes on the compressive strength of sulfur concrete. The result showed that sulfur wastes were affected by the compressive strength. Sulfur concrete which produced from sulfur by product from desulfurization unit has the highest compressive strength (2.56+0.06 MPa). The compressive strength was decrease when using sulfur wastes. However, the ratio of sulfur and modified sulfur affected the compressive strength of sulfur concrete because modified sulfur is very efficient in binding and strengthening the aggregates. The amount of modified sulfur increases, so does the compressive strength. It should be noted that sulfur concrete has been used to produce non-load bearing wall and non-load bearing concrete masony units for the propose of reduce to landfill and support sustainability concept.

Abstract: Solid biopolymer electrolytes (SBE) comprising carboxymethyl cellulose (CMC) with NH₄Br-EC were prepared by solution casting method. The samples were characterized by impedance spectroscopy (EIS) and sample containing 25wt. % of NH₄Br exhibited the highest room temperature conductivity of 1.12 x 10^-4 S/cm for salted CMC based SBE system. The ionic conductivity increased to 3.31 x 10^-3 S/cm when 8 wt. % of ethylene carbonate (EC) was added to the highest conductivity. The conductivity-temperature of plasticized SBE system obeys the Arrhenius relation where the ionic conductivity increases with temperature. The influence of EC addition on unplasticized CMC based SBE was found to be dependent on the number and the mobility of the ions. This results revealed that the influence of plasticizer (EC) which was confirmed play the significant role in enhancement of ionic conductivity for SBE system.

Abstract: This study introduces potential biosurfactant producing bacteria found in agro-based wastewater generated by palm oil mills. A total of 38 potential biosurfactant producing bacteria isolated from palm oil mill effluent were qualitatively screened for its tensoactive properties using drop collapse and oil spreading tests. Eleven of the 38 isolates exhibited high surface activity through the drop collapse test. The 11 isolates also exhibited clear zones ranging between diameters 2 to 3 cm through oil spreading test which indicated biosurfactant production. Further evaluations were performed quantitatively for all the 11 isolates in relation to their ability in reducing surface tension and emulsifying capability. Results from Du Nouy ring test demonstrated that the isolates successfully reduced surface tension of water from 72 mNm^-1 to below 40 mNm^-1. When tested for emulsifying properties, these isolates displayed high emulsifying activity indicating the presence of biosurfactant production. These 11 isolates namely R06, R07, R08, R10, S08, S09, S10, S11, S12, S15 and S17 were selected and identified using 16S rDNA gene sequence analysis. The results suggested that the isolates belong to the genus Bacillus.

Abstract: Neem (Azadirachta indica) leaf powder was treated with hydrogen peroxide followed by sodium hydroxide and its performance in Pb (II) removal was investigated. The characteristic of chemically treated neem leaf powder (CTNLP) was studied using Attenuated Total Reflectance Infra-red (ATR-IR) spectrometer and CHNOS Analyzer. The amount of Pb (II) adsorbed increased with increasing pH, concentration and contact time. The kinetic study indicated that adsorption equilibrium time was dependent on initial Pb (II) concentrations. The adsorption kinetic data fitted the pseudo-second-order model. The maximum adsorption capacity calculated from the Langmuir isotherm model was 227.3 mg/g. This study suggests suitable use of CTNLP as an adsorbent for treating wastewater containing Pb (II).

Abstract: In this work, we aim at highlighting the immunity of the junctionless Gate All Around (JLGAA) MOSFET against the induced interface tarps degradation at nanoscale level. In this context, a numerical investigation has been proposed to study the subthreshold behavior of the (JLGAA) MOSFET for ultra-low power applications. Based on 2-D numerical investigation, a small-signal parameters model for nanoscale JLGAA MOSFETs, including the hot-carrier induced interface charge effects, is developed. The numerical analysis has been used to simulate the transconductance and output-conductance in subthreshold region and to compare the performance of the investigated design and conventional GAA MOSFET, where the hot-carrier effects are included. High reliability, low fabrication cost and integration ability make JLGAA MOSFET promising candidate to improve the device reliability for the ultra-low power applications.

Abstract: When SiC particles are added into aluminum, property of aluminum is greatly improved during a reinforcing phase to produce particle reinforced aluminum composites. However, cutting tools wear out quickly and it is difficult to meet machining accuracy and surface quality requirements due to the rough surface produced by the reinforcement process. This paper presents a simulation model of SiC particle-reinforced aluminum matrix composites is established considering particles, cohesive elements, and material matrix. Stress distribution and surface roughness are analyzed for SiC/Al matrix composites based on the cutting process. Experiments are performed to test the degree of surface roughness using different cutting parameters. The relationship of cutting depth, cutting velocity, and feed rate per tooth to surface roughness degree is obtained for SiC/Al matrix composites. The optimization of cutting process is performed based on simulation. The results lay a foundation on the optimization of machining processes for metal matrix composites.

Abstract: Shape Memory Alloys (SMA) are promising materials for actuation in space applications, because of the relatively large deformations and forces that they offer. However, their complex behaviour and interaction of several physical domains (electrical, thermal and mechanical), the study of SMA behaviour is a challenging field. Present work aims at correlating the Finite Element (FE) analysis of SMA with closed form solutions and experimental data. Though sufficient literature is available on closed form solution of SMA, not much detail is available on the Finite element Analysis. In the present work an attempt is made for characterization of SMA through solving the governing equations by established closed form solution, and finally correlating FE results with these data. Extensive experiments were conducted on 0.3mm diameter NiTinol SMA wire at various temperatures and stress conditions and these results were compared with FE analysis conducted using MSC.Marc. A comparison of results from finite element analysis with the experimental data exhibits fairly good agreement.

Abstract: The diffusion bonding of Ti to Ti, Ti-Cu alloy at different temperatures ranging from 673 K to 923 K under an applied stress of 100 MPa for 1 h was studied. The observation of the microstructure reveals that sound joints between the Ti-Ti and dissimilar titanium/Copper metals sheet were successfully joined by diffusion bonding process. Ti-Cu alloy without any pores or cracks can be achieved through diffusion bonding at temperatures over 873 K under the applied stress of 100 MPa for 1 h. The bond is composed of the zones, and its width increases with the increase of bonding temperature. The Micro hardness at the interface of joints bonded under different conditions was evaluated through Micro hardness testing and the fracture mode was analyzed by SEM observation.

Abstract: This paper presents determination of flow curve of steel by using multi regression analysis based on only few experimental points of torsion test. It is necessary to know the flow curve of the formed metal and the best way to obtain one are different experiments such as tensile, upsetting or torsion tests. In the paper torsion test was used for obtaining the flow curve. In torsion test a cylindrical specimen is twisted by torque acting around its axis. Experimental data of torsion test were processed by determination of statistical characteristic of experimental results.