National Institute of Technology Rourkela

In this article, studies on kinetics and thermodynamics of sugarcane bagasse (SB) pyrolysis using thermogravimetric data have been carried out. The optimization of the process parameters involved in thermal pyrolysis was also investigated using a statistical technique called response surface methodology. The investigations on the physical properties of SB have revealed the presence of a high amount of volatile matter of about 79.54 wt% and less ash content of 3.02 wt% and a heating value of 18.27 MJ/kg. The thermogravimetric analysis of SB was performed at 5, 10, 15, and 20 °C/min heating rate under the inert atmosphere of nitrogen with a flow rate of 100 ml/min. The thermogravimetric studies have confirmed that the maximum degradation occurred in the temperature range of 200–500 °C. The kinetic parameters of SB pyrolysis at different heating rates were estimated by using Mampel’s first-order model-fitting method. The kinetic study has manifested an optimum activation energy value of 83.56 kJ/mol at 10 °C/min and a lower activation energy of 76.22 kJ/mol at 15 °C/min. The average activation energy of all the heating rates was obtained to be 79.04 kJ/mol. The thermodynamic studies affirmed an average ΔS value of − 150.27 J/K/mol, ΔH value of 73.819 kJ/mol, and ΔG value of 168.294 kJ/mol, respectively. The optimization studies showed that the maximum bio-oil yield was 43.02 wt% at optimum parameters such as the temperature of 500 °C, a nitrogen flow rate of 100 ml/min, and a heating rate of 20 °C/min, respectively. The gross calorific value and kinematic viscosity of the bio-oil obtained at optimum condition were found to be 34.02 MJ/kg and 14.20 cSt., respectively. It was also observed that the bio-oil obtained at optimum conditions contains a high amount of water of 23.70% attributing to a lesser calorific value of the bio-oil. Hence, it can be corroborated that the properties like water content, conradsons carbon residue, oxygen content, and kinematic viscosity need to be upgraded to make it a viable fuel source.

In the present work, nitrate intercalated zinc aluminium layer double hydroxide (ZA-LDH) nanoparticles in the hydrodynamic particle size range between 210 and 530 nm were synthesised using co-precipitation method under reflux condition and nitrogen atmosphere. The pristine ZA-LDH nanoadsorbent was characterised using X-ray diffraction (XRD), Fourier transformation spectroscopy (FTIR), and field emission scanning electron microscopy (FESEM). The results revealed the formation of single-phase ZA-LDH nanopowder with sheet-like morphology. The optimisation of adsorption kinetic parameters with the fixed dose of 10 mg for 50 ml of 0.03 mg/ml MO and AY dye solution was performed using the Box Behnken design model (BBD). The effects of three independent variables such as incubation time, temperature and pH of the suspended ZA-LDH nanoadsorbents in the MO and AY dye solution on the adsorption kinetics were studied. Optimum values for the maximum adsorption capacity were evaluated that included the incubation time of 52.4 min, the temperature of 35.45 +/- 0.55degree celsius, and the pH of 5.75 +/- 0.75. According to the BBD model, ZA-LDH nanoadsorbent exhibited the maximum adsorption percentage of 99.84% and 99.99% of corresponding MO and AY dye, respectively. The ZA-LDH adsorbent retained up to 72.3% for the MO and 60.43% for the AY dye of regeneration capacity after 5 cycles of regeneration. The adsorption kinetic and isotherm of the MO and AY dyes onto the ZA-LDH nanoadsorbent were well fitted with pseudo second order kinetic model and Langmuir model, respectively. According to Langmuir isotherm, the maximum adsorption capacities of 601.62 mg/g for the MO dye and 462.48 mg/g for the AY dye onto the ZA-LDH were found and those confirmed the monolayer chemisorption mechanism in this case.

Classroom practices form an array of integrated teaching and learning strategies conducive to the real world. Lesser is known about the classroom practices experiences among the students belonging to the informal settlements in private schools of India. The paper presents a brief insight into barriers to classroom practices with a self -prepared assessment tool, namely Classroom Practice Position (CPP). It can aid teachers in prioritising practices for balancing participation in the classroom. The measure will help to determine the placement of classroom routine activities. The paper highlights the data from the perspectives of 58 students in Rourkela (a city in the State of Odisha, India) through a sequential exploratory method and data analysis with SPSS v.20. The CPP tool indicates that peer support from the well-performing students helps in mitigating stereotypes, in completion of classwork, identity and familiarity with teachers.

This paper introduces an on-chip partial self-healing technique that address the mismatch-constraints in current steering digital-to-analog converters (CS-DACs) with reused distributed architecture. In contrast to the conventional calibration techniques, this method provides the flexibility to decide the combination of current cell matrices depending up-on the percentage of mismatch error and attain satisfactory static linearity. A novel current comparator is also proposed, which can detect a very low mismatch current. To validate the proposed technique, a 10-bit CS-DAC is designed with on-chip partial self-healing method using 180 nm CMOS process. The core area of the DAC is 0.64 mm 2 including 0.1 mm 2 calibration unit area with 22.4 mW power dissipation. With partial self-healing, the mismatch simulated INL and DNL value of the CS-DAC is 0.47 and 0.24 least significant bits (LSB), respectively, which shows more than 66% improvements. The proposed CS-DAC achieves 65.24 dB spurious free dynamic range (SFDR) for 53 MHz input signal with 500 MSPS sampling rate.

The demand for vibrational energy harvesting systems has increased over the past decade. The motivation for the researchers in this area is to decrease the requirement of the external power sources and reduce the maintenance cost. In the present analysis, the energy harvesting capability of a tapered laminated composite beam integrated with piezoelectric stacks is studied with respect to geometry and material properties. The substrate material is made up of laminated carbon fiber-reinforced epoxy composite with different fiber orientations, and piezoelectric patches are attached on top and bottom surfaces. In order to solve the dynamic analysis, three-dimensional finite element analysis is carried out. Here, the piezoelectric layers are modeled using PZT-5H material type. Initially, the model is validated with the available literature results and is found to be in good agreement. Furthermore, the laminated composite beam is base excited at the resonant frequency and the effect of different geometrical parameters, material parameters, and stacking sequences of the lamina on the voltage and power output is studied. Both series and parallel configurations are accounted in the present analysis.