Thermal Evaluation of Diesel/Hydrogen Peroxide Fuel Blend

Thermal properties of fossil fuel are the key fundamental characteristics, which can distinguish any compound as a potential fuel. The performance of diesel fuel blend along with stability and solubility parameter designs are evaluated. The results from the experimental study indicate that the increase in hydrogen peroxide (H₂O₂) amount enhances the cetane number of diesel fuel blend significantly. However, the calorific value decreases as compared to pure diesel fuel. All values performed well according to the ASTM D‐975 diesel testing method. The thermodynamics of the prepared fuel blends also revealed that substantial solubility and diesel/H₂O₂ blend stability are provided even at lower temperatures. Such blends can be used as a feasible replacement of pure diesel fuel.     

Current scenario and potential of biodiesel production from waste cooking oil in Pakistan: An overview

Biodiesel utilization has been rapidly growing worldwide as the prime alternative to petrodiesel due to a global rise in diesel fuel demand along with hazardous emissions during its thermochemical conversion. Although, several debatable issues including feedstock availability and price, fuel and food competition, changes in land use and greenhouse gas emission have been raised by using edible as well as inedible feedstocks for the production of biodiesel. However, non-crop feedstocks could be a promising alternative. In this article, waste cooking oils have been recommended as a suitable option for biodiesel production bearing in mind the current national situation. The important factors such as the quantity of waste cooking oil produced, crude oil and vegetable oil import expenses, high-speed diesel imports, waste management issues and environmental hazards are considered. Moreover, process simulation and operating cost evaluation of an acid catalyzed biodiesel production unit are also conducted. The simulation results show that the production cost of waste cooking oil-based biodiesel is about 0.66USD·L^-1. We believe that the present overview would open new pathways and ideas for the development of biofuels from waste to energy approach in Pakistan.     

Structural,viscoelastic, and vulcanization study of sponge ethylene–propylene–diene monomer composites with various carbon black loadings

In this article, we report the effect of various carbon nanoparticle concentrations on the structural, curing, tan δ, viscosity variation during vulcanization, thermal, and mechanical characteristics of ethylene–propylene–diene monomer polymer sponge composites. The purpose of this study was to develop high‐strength, foamy‐structure polymer composites with an optimum filler to matrix ratio for advanced engineering applications. We observed that the structural, vulcanization, viscoelastic, and mechanical properties of the fabricated composites were efficiently influenced with the progressive addition of carbon content in the rubber matrix. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39423.     

Investigation of improved dielectric and thermal properties of ternary nanocomposite PMMA/MXene/ZnO fabricated by in-situ bulk polymerization

Electric power system applications demand for high-temperature dielectric materials. The improved performance of polymer nanocomposites requires improvement in their thermal conductivity & stability, dielectric stability and processing technique. However, they often lose their dielectric properties with a rise in temperature. Here, we offer a solution by incorporating electrically conducting material (MXene) and semiconducting inorganic nanoparticles (ZnO NPs) into an insulating PMMA polymer matrix to maintain high dielectric constant, both at the room and high temperature. Therefore, to achieve desirable thermal and dielectric properties is the main objective of the present study based on the homogeneous distribution of the nanofillers by in-situ bulk polymerization assisted by strong sonication in the corresponding polymer. The introduction of MXene and ZnO NPs into the PMMA not only acquires a substantial increment in the dielectric constant, to attain a value 437, with minimum energy loss of 0.36 at 25 Hz, but also improves the thermal conductivity of PMMA up to 14 times by causing the reduction of thermal resistance, which is actually responsible for the poor thermal conductivity of amorphous pure PMMA polymer. More importantly, hybrid PMMA/4:2 wt% MXene:ZnO nanocomposite leads to an excellent thermal stability. Moreover, further characterization of the synthesized nanocomposites by FTIR, SEM and XRD leads to the evaluation of strong interaction of ternary components with PMMA matrix.     

Surface modification of mild steel with Boron Carbide reinforcement by electron beam melting

We investigated the effect of surface hardening and micro-structural modifications in Mild steel (MS) with the addition of Boron Carbide, melted by thermionic electron beam. Boron Carbide in the form of powder was added by making grooves in MS samples to trap the molten solution for interaction with solid particles. These samples were irradiated by 10 KeV electron beam with variable beam current (50-100 mA). XRD confirmed the addition of Boron Carbide in the matrix and SEM indicated micro-structural changes introduced by the electron beam. Micro-structural modification further revealed that ferrites have been transformed into dendrites and pearlites have been refined as a result of re-solidified melt. This significantly has enhanced the surface hardness greater than 6-times compared to as received Mild steal.     

Identification of Bioactivity,Volatile and Fatty Acid Profile in Supercritical Fluid Extracts of Mexican arnica

Supercritical fluid extraction (SFE) is a sustainable technique used for the extraction of lipophilic metabolites such as pigments and fatty acids. Arnica plant is considered a potential candidate material with high antioxidant and antimicrobial activities. Therefore, in this study, a locally available Heterotheca inuloides, also known as Mexican arnica, was analyzed for the extraction of high-value compounds. Based on different pressure (P), temperature (T), and co-solvent (CoS), four treatments (T) were prepared. A maximum 7.13% yield was recovered from T2 (T = 60 °C, P = 10 MPa, CoS = 8 g/min), followed by 6.69% from T4 (T = 60 °C, P = 30 MPa, CoS = 4 g/min). Some bioactive sesquiterpenoids such as 7-hydroxycadalene, caryophyllene and δ-cadinene were identified in the extracts by GC/MS. The fatty acid profile revealed that the main components were palmitic acid (C16:0), followed by linoleic acid (C18:2ω6c), α-linolenic acid (C18:3ω3) and stearic acid (C18:0) differing in percent yield per treatment. Antibacterial activities were determined by the agar diffusion method, indicating that all the treatments exerted strong antibacterial activity against S. aureus, C. albicans, and E. coli strains. The antioxidant capacity of the extracts was also measured by three in vitro assays, DPPH, TEAC and FRAP, using Trolox as a standard. Results showed high antioxidant capacity enabling pharmaceutical applications of Mexican arnica.     

Design and analysis of novel micro displacement amplification mechanism actuated by chevron shaped thermal actuators

This paper presents design and analysis of microelectromechanical system (MEMS) based displacement amplification mechanism actuated using thermal actuators with enhanced performance. The proposed model consists of chevron shaped thermal actuators, an amplification mechanism capable of amplifying displacement 20 times and an electrostatic comb drives for sensing displacements. When voltage is applied to thermal chevrons, displacement is produced which is then amplified 20 times. Steady state static thermal electrical analysis is performed under variable resistivity and voltage bias of 2 V. In-plane reaction forces of magnitude 194.2 and 150.91 µN along X and Y-axis, respectively, thus producing displacement of 0.11 and 2.22 µm along X and Y-axis, respectively. Time domain simulations of device are carried with constant electrical resistivity, variable voltage and convective boundary conditions. Modal analysis of the mechanism is carried out to predict the natural frequencies and associated mode shapes of mechanism during free vibrations. The desired mode is at frequency of 286.160 kHz. Dynamic simulations including direct integration-transient, transient modal and steady state modal analysis are performed on the device for time span of 0.0006 s, under application of 25 g and frequency range of 200–300 kHz. Simulation results prove the viability of the mechanism as an amplification device with enhanced voltage–stroke ratio.

     

A review on fault detection and diagnosis techniques: basics and beyond

Safety and reliability are absolutely important for modern sophisticated systems and technologies. Therefore, malfunction monitoring capabilities are instilled in the system for detection of the incipient faults and anticipation of their impact on the future behavior of the system using fault diagnosis techniques. In particular, state-of-the-art applications rely on the quick and efficient treatment of malfunctions within the equipment/system, resulting in increased production and reduced downtimes. This paper presents developments within Fault Detection and Diagnosis (FDD) methods and reviews of research work in this area. The review presents both traditional model-based and relatively new signal processing-based FDD approaches, with a special consideration paid to artificial intelligence-based FDD methods. Typical steps involved in the design and development of automatic FDD system, including system knowledge representation, data-acquisition and signal processing, fault classification, and maintenance related decision actions, are systematically presented to outline the present status of FDD. Future research trends, challenges and prospective solutions are also highlighted.

     

Extended Kalman filter based speeds estimation of series-connected five-phase two-motor drive system

The multi-phase machines enables independent control of a few number of machines that are connected in series in a particular manner, and the supply is fed from a single voltage source inverter (VSI). The idea was first implemented for a five-phase series-connected two-motor drive system, but is now applicable to any number of phases. The number of series-connected machines is a function of the phase number of VSI. Variable speed induction motor drives without mechanical speed sensors at the motor shaft have the attractions of low cost and high reliability. To replace the sensor, information of the rotor speed is extracted from measured stator currents and voltages at motor terminals. Open-loop estimators or closed-loop observers are used for this purpose. They differ with respect to accuracy, robustness, and sensitivity against model parameter variations. This paper analyses operation of an EKF-based sensorless control of vector controlled series-connected two-motor five-phase drive system with current control in the stationary reference frame. Results, obtained with fixed voltage and fixed frequency supply fed and hysteresis current control, is presented for various operating conditions on the basis of simulation. The purpose of this paper is to report first time, the simulation results on a sensorless control of a five-phase two-motor series-connected drive system using EKF estimator.