ABSTRACT
Ammonia detection is needed in several sectors including environmental monitoring, automobile industry, and in medical diagnosis. Conducting polymers, such as polyaniline (PANI), have been utilized to develop NH3 sensors operating at room temperature. However, the performance of these sensors in terms of sensitivity and selectivity need improvement. Functionalization of conducting PANI with metal nanocomposites have shown improved sensor performance. In this work, we report a highly sensitive copper-based nanocomposite for NH3 detection. The novelty lies in utilization of copper-ethylenediamine (Cu-en) nanocomposite functionalized over PANI for gas sensing. Resistance of the 20 wt% Cu-en with PANI increased 3.8 times upon exposure to 100 ppm of NH3. The nanocomposite sensor detected NH3 concentrations as low as 2 ppm. Further, the sensing mechanism was studied by in-situ IV characteristics and impedance spectroscopy during NH3 exposure. NH3 showed ionic interaction with PANI, and Cu2+. The strong affinity of Cu2+ for the lone pair of NH3 enhanced the sensor response from 0.78 to 3.8 for 100 ppm of NH3 at 20 °C. The sensor response was completely recovered after heating at 75 °C, which indicates reusability of the sensor. The sensor showed selectivity for NH3 over ethanol and H2S. The response was reasonably stable after bending the flexible sensor for 1000 times at a radius of 5 mm.
ABSTRACT
This work analyses the performance and emission characteristics of biofuelled compression ignition (C.I) engine with the implementation of an antioxidant. Using the transesterification process with sodium hydroxide as a catalyst, the beef tallow methyl ester (BTME) was obtained from the beef tallow oil. Poor physical properties of biodiesel (beef tallow oil (BTO)) namely high viscosity and density cause atomization problems leading to higher smoke, hydrocarbon and carbon monoxide emissions. The purpose of this work is to enhance the performance aspects, to limit smoke emissions from BTO operation and to examine the possibility of direct use of neat BTO in CI engine. This research paves a way of investing the impact of binary blends of BHA and BTO on the research engine. The experiments were conducted on a single-cylinder four-stroke C.I engine using the following fuel compositions: 20% of BTME mixed with 80% diesel (B20), 1000 ppm mono-phenolic antioxidant (butylated hydroxyanisole (BHA)) mixed with the blends of B20 (B20 + BHA), and 100% diesel. Based on the experimental results, it was found that the brake thermal efficiency (BTE) increases by 1.8% and the brake specific fuel consumption (BSFC) decreases by 2.5% for the fuel blend B20 + BHA when compared with that for B20 fuel blend. Compared with the B20 blend, the blend B20 + BHA emits 12.2% lesser nitrogen oxide due to breaking chain reactions, scavenging the initiating radicals and reducing the concentration of reactive radicals.
