Effect of annealing on the wrinkling behaviour of the commercial pure aluminium grades when drawn through a conical die

Experiments have been carried out to evaluate the onset of wrinkling behaviour in three grades of annealed commercial aluminium sheets namely ISS 19000, ISS 19600 and ISS 19660 having thickness 2.00 mm, while drawing them through a conical die. The deep drawing of circular blanks of different diameters of the aforesaid sheet metals was carried out using flat bottom punch. The analysis of the experimental data has revealed that the onset of wrinkling takes place when the ratio of the plastic strain increments (dε_r/dε_θ) reached a critical value. It was further found that the measured strains followed non-linear paths in the wrinkling limit diagrams. Further, it was observed that the aluminium grade having high strain hardening index value, low yield stress and high normalized hardening rate shows better resistance against wrinkling. Furnace cooled aluminium grades showed better resistance against wrinkling compared with air cooled blanks.     

The adoption and concerns of e-finance in Malaysia

Technological advancement has brought a whole new way of delivering financial services around the world. E-finance industry in Malaysia has grown rapidly with the help of internet and conducting financial services are far easier now if compared to last time. Internet provided a new medium or channel in delivering financial services. However, there are also risks and challenges when using electronic finance. A total of 100 respondents had been targeted in completing this study. Survey method was utilized in collecting respondent’s opinion and perception to test the variables. The target was companies which used electronic finance in delivering their services. Interviews were also conducted and relevant tests conducted which provided evidence to support the hypotheses for this study. It was found that e-finance was affected by security, revenue and cost dimensions, and technology architecture with the adoption of global technology.     

Optimization of Lithium Content and Sintering Aid for Maximized Li+ Conductivity and Density in Ta‐Doped Li7La3Zr2O12

Ta‐doped cubic phase Li₇La₃Zr₂O₁₂ (LLZ) lithium garnet received considerable attention in recent times as prospective electrolyte for all‐solid‐state lithium battery. Although the conductivity has been improved by stabilizing the cubic phase with the Ta⁵⁺ doping for Zr⁴⁺ in LLZ, the density of the pellet was found to be relatively poor with large amount of pores. In addition to the high Li⁺ conductivity, density is also an essential parameter for the successful application of LLZ as solid electrolyte membrane in all‐solid‐state lithium battery. Systematic investigations carried out through this work indicated that the optimal Li concentration of 6.4 (i.e., Li_6.4La₃Zr_1.4Ta_0.6O₁₂) is required to obtain phase pure, relatively dense and high Li⁺ conductive cubic phase in Li_7?xLa₃Zr_2?xTa_xO₁₂ solid solutions. Effort has been also made in this work to enhance the density and Li⁺ conductivity of Li_6.4La₃Zr_1.4Ta_0.6O₁₂ further through the Li₄SiO₄ addition. A maximized room‐temperature (33°C) total (bulk + grain boundary) Li⁺ conductivity of 3.7 × 10^?4 S/cm and maximized relative density of 94% was observed for Li_6.4La₃Zr_1.4Ta_0.6O₁₂ added with 1 wt% of Li₄SiO₄.     

Microstructural,physico-chemical and mechanical characterisation of Sansevieria cylindrica fibres – An exploratory investigation

The microstructural, physical, chemical and mechanical properties of Sansevieria cylindrica fibres are described for the first time in this work. A microstructural analysis of S. cylindrica leaves showed the presence of structural fibres and arch fibres. Polarised light microscopy and scanning electron microscopy of these fibres revealed a hierarchical cell structure that consisted of a primary wall, a secondary wall, a fibre lumen and middle lamellae. The cross-sectional area and porosity fraction of the fibre were estimated to be approximately 0.0245 mm² and 37%, respectively. The fibre density and fineness were approximately 0.915 ± 0.005 g/cm³ and 9 Tex, respectively. An X-ray diffraction and Fourier transform infrared analysis of the fibres showed the presence of cellulose I_β with a crystallinity index of 60%. Tensile tests showed that the corrected Young’s modulus was approximately 7 GPa, the tensile strength was 658 MPa, and the total elongation was between 10% and 12%.     

Phenomenon of Barrelling in Square Billets of Aluminium During Cold Upset Forging

Experiments were carried out to generate data on the upset forging of square billets of annealed aluminium. The measured curvatures of the barrelled aluminium square billets were found to conform with calculated values using experimental data. The calculations were made on the assumption that the curvature of the barrel followed the geometry of a circular arc. It was further found that the measured radius of curvature of the barrel exhibited a straight-line relationship with the new geometrical shape factor irrespective of the aspect ratios of the square billets. Further empirical relationships were found to exist between the measured radius of curvature of the barrel and independently with other variables like hydrostatic stress and stress ratio parameter.     

Performance and emission analysis of methyl ester of Azolla algae with TiO2 Nano additive for diesel engine

The present work investigates the effect of using TiO₂ Nanoparticles at a different proportion of Azolla algae methyl ester, in a four-stroke single cylinder diesel engine. Biodiesel can be obtained from Azolla algae due to the presence of high oil content. The oil was extracted from Azolla algae by means of the Soxhlet extraction method which was compared to be more effective than the oil obtained by means of hydraulic pressing machine. The obtained oil was converted to biodiesel by means of transesterification process. The fuel properties of the prepared Azolla methyl ester found to confirm with the ASTM standards. TiO₂ Nanoparticles were synthesized by means of ball milling process and characterized by means of Scanning Electron Microscope (SEM), Atomic Force Microscopy (AFM), Fourier Transform Infrared (FTIR) and X-Ray Diffraction (XRD) techniques. In the present study, the performance and emission characteristics of diesel engine were analyzed with the addition of TiO₂ Nanoparticles to Azolla oil methyl ester (25,50,75 and100 ppm) and compared with that of diesel. The % decrease in Brake Specific Fuel Consumption (BSFC) for B20 + 25, B20 + 50, B20 + 75 and B20 + 100 were found to be 7.81, 12.05, 19.71, and 23.53, respectively, when compared to B20. The % increase in Brake Thermal Efficiency (BTE) for B20 + 25, B20 + 50, B20 + 75 and B20 + 100 were found to be 2.60, 8.49, 8.79 and 13.38, respectively, when compared to B20. The % decrease in Carbon monoxide (CO) for B20 + 25, B20 + 50, B20 + 75 and B20 + 100 were found to be 21.15, 51.92, 54.80, and 57.30, respectively, when compared to B20. The % decrease in Hydro Carbon (HC) for B20 + 25, B20 + 50, B20 + 75 and B20 + 100 were found to be 7.53,8.36,10.04 and 12.97, respectively, when compared to B20. The % increase in Oxides of Nitrogen (NOx) for B20 + 25, B20 + 50, B20 + 75 and B20 + 100 were found to be 5.44, 7.85, 8.67, and 9.16, respectively, when compared to B20. The % decrease in smoke for B20 + 25, B20 + 50, B20 + 75 and B20 + 100 were found to be 18.02, 30.18, 31.98 and 36.04, respectively, when compared to B20. Addition of TiO₂ Nanoparticles with the Azolla biodiesel is found to be an effective approach to improve the performance and emission characteristics of a diesel engine without any modification.     

Triangular‐shaped super‐thin microwave network cloak in antenna applications

In this research article, a triangular‐shaped microwave network cloak made out of interconnected patches was designed at the frequency of 2.88 GHz. Its performances in terms of field distributions and radar cross section scattering were compared with the existing structures. The novel triangular‐shaped cloak structure was then applied to cloak a hindering obstacle placed in front of an electromagnetic source. The simulated scattering parameter and radiation pattern of antenna source were then validated through the experimental results. Also, the proposed structure was applied to reduce the mutual interference between two neighboring antennas. The effects of various parameters such as position and size of the cloak, dielectric constant, and substrate thickness on the cloaking effect were also simulated and studied.     

Some aspects on plastic deformation of copper and copper–titanium carbide powder metallurgy composite preforms during cold upsetting

The densification, workability and strain hardening behaviour of sintered copper and Cu–7.5%TiC powder metallurgy (P/M) composite preforms during cold upsetting were investigated by the constitutive model using the experimental data. Cold upsetting of copper and Cu–7.5% TiC composite preforms having different aspect ratios were carried out and the formability behaviour of the preforms under triaxial stress state was determined. The mechanisms most likely involved in the constitutive model, namely, densification and strain hardening were studied. The effects of aspect ratio and addition of titanium carbide to copper on the formability behaviour and various constants involved in the constitutive model, namely, instantaneous density coefficient, instantaneous strain hardening index, instantaneous strain rate sensitivity and instantaneous strength coefficient were discussed in detail.     

Effect of Annealing Temperature in Al 1145 Alloy Sheets on Formability, Void Coalescence, and Texture Analysis

This paper deals with a combined forming and fracture limit diagram and void coalescence analysis for the aluminum alloy Al 1145 alloy sheets of 1.8 mm thickness, annealed at four different temperatures, namely 200, 250, 300, and 350 °C. At different annealing temperatures these sheets were examined for their effects on microstructure, tensile properties, formability, void coalescence, and texture. Scanning electron microscope (SEM) images taken from the fractured surfaces were examined. The tensile properties and formability of sheet metals were correlated with fractography features and void analysis. The variation of formability parameters, normal anisotropy of sheet metals, and void coalescence parameters were compared with texture analysis.