Utilization of additives in biodiesel blends for improving the diesel engine performance and minimizing emissions through a modified Taguchi approach.

Biodiesel from Jatropha oil is produced through catalyzed homogeneous transesterification. Hydrogen peroxide (H2O2) is considered as additive. Blends of Jatropha considered in the present study are 60% diesel, (40-A)% biodiesel and A% additive, varying A from 0 to 10. Identifying optimal input variables (such as additive volume percentage, injection pressure, and load) is important for improving the engine performance and reducing emissions. Air-fuel ratio; brake specific fuel consumption (BSFC); and brake thermal efficiency (BTE) are the engine performance characteristics. Carbon monoxide (CO); carbon dioxide (CO2); exhaust gas temperature (EGT); nitrogen oxide (NOx); and smoke opacity are the emission characteristics. 27 experiments need to be performed for the assigned 3 levels and 3 input variables. The Taguchi's L9 orthogonal array (OA) is chosen to perform only 9 experiments to obtain the optimal solution. The expected range of performance characteristics and emissions was obtained following a modified Taguchi approach. Empirical relationships are developed and verified through engine performance and emission characteristics.

Mechanical alloying of Mg0.8-XTi0.2 and study the effect of adding (x = 0.2 wt%) transition metal like Sc, Zr, or Nb on their phase transitions, activation energy, and hydrogen storage properties.

Till now Mg-based alloys have attracted much attention due to the high storage capacity of hydrogen. An effort was made to evaluate the apparent activation energy and electrochemical behavior of transition metals such as scandium (Sc), zirconium (Zr), and niobium (Nb) alloyed with Mg-Ti. Mg0.8Ti0.2, Mg0.6Ti0.2Sc0.2, Mg0.6Ti0.2Zr0.2, and Mg0.6Ti0.2Nb0.2 alloy powders were synthesized using high-energy ball milling. Ballmilled powders were subjected to structural and morphological characterization using X-ray diffraction and scanning electron microscopy respectively. A strong shift in the inter-planar spacing value of milled powders confirmed supersaturated solid solution of Ti and transition metals in Mg. The inter-planar spacing values before and after milling are found to be 0.24 and 0.21 nm, respectively. Mg0.8Ti0.2, Mg0.6Ti0.2Sc0.2, and Mg0.6Ti0.2Zr0.2 alloy powders result in the FCC phase while Mg0.6Ti0.2Nb0.2 powders result in BCC phase, however, the entire powders have an amorphous background. SEM-EDS analysis of the milled powders confirmed the presence of Mg, Ti, Sc, Zr, and Nb elements with a small amount of oxygen. Selected area electron diffraction (SAED) pattern of Mg0.8Ti0.2 alloy powders exhibits a nanocrystalline nature owing to their polycrystalline ring pattern. Exothermic peak broadening increases after the substitution of Nb and Zr in Mg0.8Ti0.2 alloy powder, which exhibits a lower activation energy (188 kJ mol-1) than others. In cyclic voltammetry, a drenched cathodic peak is observed for Mg0.8Ti0.2 at a potential around -0.83 V. In electrochemical impedance spectroscopy, the charge transfer resistance of Mg0.6Ti0.2Sc0.2 is lower than that of Mg0.6Ti0.2Zr0.2 and Mg0.6Ti0.2Nb0.2 alloy but higher than Mg0.8Ti0.2 electrode materials, and charge-discharge studies were done on the developed electrode materials. It shows that Mg0.8Ti0.2 electrode material delivers a maximum discharge capacity of 535 mA h g-1.

On the Residual Stresses and Fracture Toughness of Glass/Carbon Epoxy Composites.

The resistance to delamination in polymer composite depends on their constituents, manufacturing process, environmental factors, specimen geometry, and loading conditions. The manufacturing of laminated composites is usually carried out at an elevated temperature, which induces thermal stresses in composites mainly due to a mismatch in the coefficient of thermal expansion (CTE) of fiber and matrix. This work aims to investigate the effect of these process-induced stresses on mode-I interlaminar fracture toughness (GI) of Glass-Carbon-Epoxy (GCE) and Glass-Epoxy (GE) composites. These composites are prepared using a manual layup technique and cured under room temperature, followed by post-curing using different curing conditions. Double cantilever beam (DCB) specimens were used to determine GI experimentally. The slitting technique was used to estimate residual stresses (longitudinal and transverse direction of crack growth) inherited in cured composites and the impact of these stresses on GI was investigated. Delaminated surfaces of composites were examined using a scanning electron microscopy (SEM) to investigate the effect of post-curing on the mode-I failure mechanism. It was found that GI of both GE and GEC composites are sensitive to the state of residual stress in the laminas. The increase in the GI of laminates can also be attributed to an increase in matrix deformation and fiber-matrix interfacial bond with the increase in post-curing temperature.

Effect of Multi-Walled Carbon Nanotubes and Carbon Fiber Reinforcements on the Mechanical and Tribological Behavior of Hybrid Mg-AZ91D Nanocomposites.

Magnesium matrix composites are extensively used in automotive and structural applications due to their low density, high strength, and wear-resistant properties. To reach the scope of industry needs, research is carried out regarding enhancing the mechanical and tribological behavior of the magnesium composites by reinforcing the nano-sized reinforcements. In the present work, research has been carried out to enhance the properties of the magnesium AZ91D hybrid composite by reinforcing carbon fibers (CFs) and multi-walled carbon nanotubes (MWCNTs) with varying weight percentages (AZ91D + 0.5% CF's + 0.5% MWCNT and AZ91D + 0.75% CF's + 0.75% MWCNT, respectively). The experimental tests were carried out to evaluate the mechanical and tribological behavior of the composites. The test results showed that the addition of CF and MWCNT reinforcements improved the hybrid Mg composite's hardness, tensile strength, and impact strength compared to the base Mg matrix. The AZ91D + 0.75% CF's + 0.75% MWCNT hybrid composite showed a 19%, 35%, and 66% increased hardness, tensile strength, and impact strength, respectively, compared to the base Mg AZ91D. The wear test results also showed the improved wear resistance of the Mg composite compared to the base matrix. The enhanced wear resistance of the composite is due to the addition of hard MWCNT and CF reinforcements. The wear rate of the AZ91D + 0.75%CF's + 0.75% MWCNT composite for a load of 30 N at a sliding distance of 1500 m is lower as compared to the base matrix. The SEM micrographs of the worn surfaces revealed the existence of abrasive wear. The improved mechanical and tribological behavior of the magnesium composite is also due to the homogeneous distribution of the hard reinforcement particles along the grain boundaries.

Performance indicators for the optimal BTE of biodiesels with additives through engine testing by the Taguchi approach.

Biodiesel commercialization is questionable due to poor brake thermal efficiency. Biodiesel utilization should be improved with the addition of fuel additives. Hydrogen peroxide is a potential fuel additive due to extra hydrogen and oxygen content, which improves the combustion process. In this experimental study, biodiesel has been produced from Jatropha oil employing catalyzed transesterification homogeneously to examine its influence on the performance and emissions at engine loads with 1500 rpm utilizing a four-stroke single-cylinder diesel engine. D60B40 (having 60% diesel and 40% biodiesel) and D60B30A10 (60% diesel, 30% biodiesel and 10% hydrogen peroxide (H2O2)), are the fuel mixtures in the current study. The addition of H2O2 reduces emissions and enhances the combustion process. This effect occurred due to the micro-explosion of the injected fuel particles (which increases in-cylinder pressure and heat release rate (HRR)). An increase of 20% in BTE and 25% reduction in BSFC for D60B30A10 was observed compared to D60B40. Significant reduction in emissions of HC up to 17.54%, smoke by 24.6% CO2 by 3.53%, and an increase in NOx was noticed when the engine is operated with D60B30A10. The HRR increased up to 18.6%, ID reduced by 10.82%, and in-cylinder pressure increased by 8.5%. Test runs can be minimized as per Taguchi's design of experiments. It is possible to provide the estimates for the full factorial design of experiments. Exhaust gas temperature standards are evaluated and examined for all fuel blends.

Statistical Analysis of Polymer Nanocomposites for Mechanical Properties.

Epoxy resins, due to their high stiffness, ease of processing, good heat, and chemical resistance obtained from cross-linked structures, have found applications in electronics, adhesives coatings, industrial tooling, and aeronautic and automotive industries. These resins are inherently brittle, which has limited their further application. The emphasis of this study is to improve the properties of the epoxy resin with a low-concentration (up to 0.4% by weight) addition of Multi-Walled Carbon Nanotubes (MWCNTs). Mechanical characterization of the modified composites was conducted to study the effect of MWCNTs infusion in the epoxy resin. Nanocomposites samples showed significantly higher tensile strength and fracture toughness compared to pure epoxy samples. The morphological studies of the modified composites were studied using Scanning Electron Microscopy (SEM).

Investigation of Mechanical and Physical Properties of Big Sheep Horn as an Alternative Biomaterial for Structural Applications.

This paper investigates the physical and mechanical properties of bighorns of Deccani breed sheep native from Karnataka, India. The exhaustive work comprises two cases. First, rehydrated (wet) and ambient (dry) conditions, and second, the horn coupons were selected for longitudinal and lateral (transverse) directions. More than seventy-two samples were subjected to a test for physical and mechanical property extraction. Further, twenty-four samples were subjected to physical property testing, which included density and moisture absorption tests. At the same time, mechanical testing included analysis of the stress state dependence with the horn keratin tested under tension, compression, and flexural loading. The mechanical properties include the elastic modulus, yield strength, ultimate strength, failure strain, compressive strength, flexural strength, flexural modulus, and hardness. The results showed anisotropy and depended highly on the presence of water content more than coupon orientation. Wet conditioned specimens had a significant loss in mechanical properties compared with dry specimens. The observed outcomes were shown at par with results for yield strength of 53.5 ± 6.5 MPa (which is better than its peers) and a maximum compressive stress of 557.7 ± 5 MPa (highest among peers). Young's modulus 6.5 ± 0.5 GPa and a density equivalent to a biopolymer of 1.2 g/cc are expected to be the lightest among its peers; flexural strength 168.75 MPa, with lowest failure strain percentage of 6.5 ± 0.5 and Rockwell hardness value of 60 HRB, seem best in the class of this category. Simulation study identified a suitable application area based on impact and fatigue analysis. Overall, the exhaustive experimental work provided many opportunities to use this new material in various diversified applications in the future.

Study of diesel engine characteristics by adding nanosized zinc oxide and diethyl ether additives in Mahua biodiesel-diesel fuel blend.

This study deals with an experimental investigation to assess the characteristics of a modified common rail direct injection (CRDI) engine utilizing diesel, Mahua biodiesel, and their blends with synthesized zinc oxide (ZnO) nano additives. The physicochemical properties of diesel, diesel + 30 ppm ZnO nanoparticles (D10030), 20% Mahua biodiesel (MOME20), and Mahua biodiesel (20%) + 30 ppm ZnO nanoparticles (MOME2030) were measured in accordance to the American Society for Testing and Materials standards. The effects of modification of fuel injectors (FI) holes (7-hole FI) and toroidal reentrant combustion chamber (TRCC) piston bowl design on the performance of CRDI using different fuel blends were assessed. For injection timings (IT) and injection opening pressure (IOP) average increase in brake thermal efficiency for fuel blend D10030 and MOME2030 was 9.65% and 16.4%, and 8.83% and 5.06%, respectively. Also, for IT and IOP, the average reductions in brake specific fuel consumption, smoke, carbon monoxide, hydrocarbon and nitrogen oxide emissions for D10030 and MOME2030 were 10.9% and 7.7%, 18.2% and 8.6%, 12.6% and 11.5%, 8.74% and 13.1%, and 5.75% and 7.79%, respectively and 15.5% and 5.06%, 20.33% and 6.20%, 11.12% and 24.8%, 18.32% and 6.29%, and 1.79% and 6.89%, respectively for 7-hole fuel injector and TRCC. The cylinder pressure and heat release rate for D10030 and MOME2030 were enhanced by 6.8% and 17.1%, and 7.35% and 12.28%. The 7-hole fuel injector with the nano fuel blends at an injection timing and pressure of 10° btdc and 900 bar demonstrated the overall improvement of the engine characteristics due to the better air quality for fuel mixing. Similarly, the TRCC cylinder bowl geometry illustrated advanced ignition due to an improved swirl and turbulence. Also, the engine test results demonstrated that 30 ppm of ZnO nanoparticles in Mahua biodiesel (MOME2030) and diesel (D10030) with diethyl ether resulted overall enhancement of CRDI engine characteristics.