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This work examines the effect of ultrasound irradiation (UI) on biodiesel properties and transesterification parameters. Methanol content, reaction time, reaction temperature, and catalyst concentration are varied, and the optimum condition for maximum possible yield was held constant for both processes. Biodiesel obtained from non-edible oils is the most promising alternative fuel for conventional diesel fuel. In this study, sterculia foetida seed oil was used for biodiesel production. Sterculia foetida oil was transesterified to lower its FFA using UI and compared with the conventional process. Both heating processes were optimized to yield a maximum of 94.3% at a six molar ratio, 50 °C, (water temp), 1% wt of catalyst (KOH), and 75 min reaction time. Transesterification by UI reduced the total reaction time to 4 min compared to 75 min at the conventional process. Further UI influenced the properties of biodiesel (SOBD) from SO. UI lowered viscosity by 7.3% and density by 5.5% and facilitated using oxygen content of SOBD., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The main objective of this study is to lower the greenhouse gases by developing and optimizing a solar flat plate collector. The rifled tube is integrated into the collector to increase the thermal heat transfer thereby improving its performance. Two flat plate collectors, one with in-housed longitudinal fins and another without fins of 0.5 m 2 collector area, have been intended and fabricated with provisions for K-type thermocouples to examine the temperature variations inside the collector for different working fluids. This current study reveals using CuO and Al 2 O 3 nanoparticles in varying weight fractions in incremental order to study the effect of weight fractions on the efficiency of the collector. The simulation was done using computational fluid dynamics both for the finned and without finned tube collectors separately and the outcome of the results for the collector outlet temperatures is compared with the experimental one and results show a valuable outcome for the intended collectors. Initially, the test was conducted with pure distilled water as working fluid and further nanoparticles were opted and doped inside the collector side for varying weight fractions of 0.2% and 0.4% and their results are compared. The experimental results showed an improved heat transfer was pragmatic in the collector side for using nanoparticles. Mixing the nanofluids exhibited superior efficiency on the collector side. The results showed after successful trials of experimentation, doping of CuO nanoparticles by varying weight fractions of 0.2% and 0.4%, augmentation of the collector (unfinned) efficiency is 2.1% and 4.05%, and similarly for finned tube collector, it is 3.02% and 5.5% for same weight fractions. In order to improve the thermal efficiency of collector, CuO is replaced by Al 2 O 3 nanoparticles; for dissimilar weight fractions, the efficiency is enhanced nearly by 3.7% and 6.54% for unfinned tube collector, and for the finned tube, the collector is 4.8% and 7.8% respectively, compared with the base working fluid (water). Experimentation of the collectors with finned tube type achieved a superior efficiency compared with that of unfinned tube collectors which is proved to be higher when used for nanofluids to that of the base working fluid water.

This work investigates the experimental study to examine the operation characteristics of a neat neem oil methyl ester (BD100) along with silver oxide nano-particles as a metal-based additive in various mass fractions. Silver oxide nano-particle is mixed into 100% of BD100 at 5 and 10 ppm. The experimental investigation on diesel engine reveals that the addition of silver oxide nano-particles to BD100 resulted in enhancement of brake thermal efficiency (BTE) with a reduction in brake specific fuel consumption (BSFC). The tested emission parameters such as CO, HC, NOx, and smoke were decreased by 12.22, 10.89, 4.24, and 6.61% for BD100+ Ag 2 O (5 ppm) and 16.47, 14.21, 6.66, and 8.34% for BD100 respectively when compared to BD100. Overall, improvement in ignition characteristics of the engine was finer by adding 5 and 10 ppm of silver oxide nano-particle to BD100 on account of the enhanced surface area to volume ratio.

The current work focuses on the experimental investigation to analyze the combustion and emission characteristics of a direct injection diesel engine fueled with neat biodiesel (BD100) and different proportions of cyclohexanol blends as a fuel additive in various volume fractions. Cyclohexanol is dispersed into a neat biodiesel in a volume fraction of 10, 20, and 30 vol%. The biodiesel is produced from neem oil by the conventional transesterification process. The experimental results revealed that with the increased cyclohexanol fraction, the combustion was found smooth. The addition of cyclohexanol has a positive influence on various physical and chemical properties of neat biodiesel. The in-cylinder pressure is comparatively low for diesel followed by cyclohexanol and biodiesel blends when compared with neat biodiesel. This is due to shorter ignition delay period. The heat-release rate of neat biodiesel is the highest among all fuels. The overall HC emission of BD70COH30 is 12.19% lower than BD100 and 16.34% lower than diesel. The overall CO 2 emission of BD70COH30 is 13.91% higher than BD100 and 19.5% higher than diesel. The overall NO x emission of BD70COH30 is 5.31% lower than BD100 at all load engine operations. The presence of 10, 20, and 30% of cyclohexanol in biodiesel decreased smoke emissions as compared with neat biodiesel and diesel. The overall smoke emission of BD70COH30 is 19.23% lower than BD100 and 25.51% lower than diesel. The overall CO emission of cyclohexanol blended with biodiesel by 30 vol% (BD70COH30) is 17% lower than neat biodiesel and 21.8% lower than diesel. Based on the outcome of this study, neem oil biodiesel and cyclohexanol blends can be employed as a potential alternative fuel for existing unmodified diesel engines owing to its lesser emission characteristics.

In this study, the effect of blending pentanol to biodiesel derived from mahua oil on emissions and performance pattern of a diesel engine under exhaust gas recirculation (EGR) mode was examined and compared with diesel. The purpose of this study is to improve the feasibility of employing biofuels as a potential alternative in an unmodified diesel engine. Two pentanol-biodiesel blends denoted as MOBD90P10 and MOBD80P20 which matches to 10 and 20 vol% of pentanol in biodiesel, respectively, were used as fuel in research engine at 10 and 20% EGR rates. Pentanol is chosen as a higher alcohol owing to its improved in-built properties than the other first-generation alcohols such as ethanol or methanol. Experimental results show that the pentanol and biodiesel blends (MOBD90P10 and MOBD80P20) have slightly higher brake thermal efficiency (0.2-0.4%) and lower brake-specific fuel consumption (0.6 to 1.1%) than that of neat biodiesel (MOBD100) at all engine loads. Nitrogen oxide (NOx) emission and smoke emission are reduced by 3.3-3.9 and 5.1-6.4% for pentanol and biodiesel blends compared to neat biodiesel. Introduction of pentanol to biodiesel reduces the unburned hydrocarbon (2.1-3.6%) and carbon monoxide emissions (3.1-4.2%) considerably. In addition, at 20% EGR rate, smoke, NO X emissions, and BTE drop by 7.8, 5.1, and 4.4% respectively. However, CO, HC emissions, and BSFC increased by 2.1, 2.8, and 3.8%, respectively, when compared to 0% EGR rate.

The present work is intended to investigate the emission characteristics of neat cashew nut shell methyl ester (CNSME100) by adding pentanol at two different proportions and compared with the baseline diesel. CNSME100 is prepared by the conventional transesterification process. CNSME100 is chosen due to its non-edible nature. Pentanol is chosen as an additive because of its higher inbuilt oxygen content and surface to volume ratio which reduces the drawbacks of neat CNSME100. Emission characteristics were carried out in single cylinder naturally aspirated CI engine fuelled with neat cashew nut shell methyl ester (CNSME), cashew nut shell methyl ester and pentanol by 10% volume (CNSME90P10), cashew nut shell methyl ester and pentanol by 20% volume (CNSME80P20), and diesel. This work also aims to investigate the feasibility of operating an engine fuelled with neat methyl ester and alcohol blends. Experimental results showed that by blending higher alcohol to neat cashew nut shell methyl ester reduces the emissions significantly. It is also found that the emission from neat methyl ester and pentanol blends is lesser than diesel at all loads.