Fibre composite railway sleeper design by using FE approach and optimization techniques

This research work aims to develop an optimal design using Finite Element (FE) and Genetic Algorithm (GA) methods to replace the traditional concrete and timber material by a Synthetic Polyurethane fibre glass composite material in railway sleepers. The conventional timber railway sleeper technology is associated with several technical problems related to its durability and ability to resist cutting and abrading action of the bearing plate. The use of pre-stress concrete sleeper in railway industry has many disadvantages related to the concrete material behaviour to resist dynamic stress that may lead to a significant mechanical damage with feasible fissures and cracks. Scientific researchers have recently developed a new composite material such as Glass Fibre Reinforced Polyurethane (GFRP) foam to replace the conventional one. The mechanical properties of these materials are reliable enough to help solving structural problems such as durability, light weight, long life span (50-60 years), less water absorption, provide electric insulation, excellent resistance of fatigue and ability to recycle. This paper suggests appropriate sleeper design to reduce the volume of the material. The design optimization shows that the sleeper length is more sensitive to the loading type than the other parameters

Mechanical treatment of microorganisms using ultrasound, shock and shear technology

Microorganism disruption using ultrasound treatment is the focus of this thesis. There has been aboard spectrum of theoretical and experimental work on microorganisms disruption methods undertaken in the past. However, there is a lack of fundamental understanding on the actual reason of microorganism disruption using ultrasound. The reported literature in the microorganisms and cell disruption research field indicates that shock wave and shear effects occur together in typical ultrasound processing systems and may both contribute to microorganism disruption. However the question of whether the real cause of disruption is shock and/or shear remains unanswered. To address this issue, two independent mechanical devices – a shock apparatus and a shear apparatus were developed for this study. An ultrasound apparatus operated in a batch configuration was also used for microorganism disruption. The ultrasound work includes a detailed experimental characterisation of processing conditions associated with the ultrasound treatment. The heat transfer through the ultrasound chamber and the suspension mixing during the ultrasound treatment was evaluated using theoretical and experimental approaches. It was found that one second was sufficient to have complete suspension mixing in the ultrasound chamber and 13.5% of the total ultrasound energy was lost to the surroundings as heat. Saccharomyces cerevisiae was selected as a sample microorganism in this study, and a log reduction of 4 was achieved when ultrasound treatment was used. To determine how the yeast cell wall disrupts using a shock treatment, a finite element model was developed and the simulation results showed that von Mises stress generated due to dynamic external pressure loading was concentrated at the bottom part of the cell wall of the yeast. A vertical gas gun was commissioned to apply a dynamic load on a water-filled tube. To understand the relationship between the dynamic stress and the microorganism behaviour when subjected to external pressure, a plastic bag full of yeast suspension was placed at the bottom of the tube. The result showed that the yeast disruption rate using the shock wave treatment was relatively modest when an external shock loading pressure of around 115 MPa was used. In the case of shear stress treatment, analysis of the intense turbulent flow region of the apparatus combined with the experimental results demonstrated that when the energy dissipation rate in the turbulence region is high and the eddies are smaller than the size of the cell, the likehood of yeast disruption is high. The microorganism mechanical properties combined with the calculated energy dissipation rate were used to simulate the yeast disruption efficiency using shear stress. The results showed that a maximum yeast log reduction of 4 was achieved with the shear apparatus in the absence of pressure rise. The specific energy required for yeast disruption in these three mechanical methods was evaluated and a comparison was made with two relevant conventional methods: homogenizer and Ultra High Temperature (UHT) treatments. It was found that the specific energy required to achieve a log reduction of 2.5 was 108 MJ/kg in the case of shear and around 0.905 MJ/kg in the case of ultrasound. In the case of shock treatment, the maximum log reduction achieved was 0.57 which required 0.00477 MJ/kg. Therefore, on the assumption that log reduction is proportional to the specific treatment energy, for a 1 log reduction, 0.008 MJ/kg is required for the shock treatment, 0.46 MJ/kg is required for the ultrasound treatment, and around 48 MJ/kg is required for the shear treatment. These results show that shock wave treatment requires less specific energy to achieve the same yeast log reduction as the shear or ultrasound treatment. This implies that the cause of microorganism disruption using ultrasound is shock wave energy. Additional work in the finite element simulation and shock treatment apparatus is recommended to extend this study to different microorganisms and cells

Recycling of waste engine oils using a new washing agent

This paper addresses recycling of waste engine oils treated using acetic acid. A recycling process was developed which eventually led to comparable results with some of the conventional methods. This gives the recycled oil the potential to be reused in cars' engines after adding the required additives. The advantage of using the acetic acid is that it does not react or only reacts slightly with base oils. The recycling process takes place at room temperature. It has been shown that base oils and oils' additives are slightly affected by the acetic acid. Upon adding 0.8 vol% of acetic acid to the used oil, two layers were separated, a transparent dark red colored oil and a black dark sludge at the bottom of the container. The base oils resulting from other recycling methods were compared to the results of this paper. The comparison showed that the recycled oil produced by acetic acid treatment is comparable to those recycled by the other conventional methods

Combustion analysis of a CI engine performance using waste cooking biodiesel fuel with an artificial neural network aid

[Abstract]: A comprehensive combustion analysis has been conducted to evaluate the performance of a commercial DI engine, water cooled two cylinders, in-line, naturally aspirated, RD270 Ruggerini diesel engine using waste vegetable cooking oil as an alternative fuel. In order to compare the brake power and the torques values of the engine, it has been tested under same operating conditions with diesel fuel and waste cooking biodiesel fuel blends. The results were found to be very comparable. The properties of biodiesel produced from waste vegetable oil was measured based on ASTM standards. The total sulfur content of the produced biodiesel fuel was 18 ppm which is 28 times lesser than the existing diesel fuel sulfur content used in the diesel vehicles operating in Tehran city (500 ppm). The maximum power and torque produced using diesel fuel was 18.2 kW and 64.2 Nm at 3200 and 2400 rpm respectively. By adding 20% of waste vegetable oil methyl ester, it was noticed that the maximum power and torque increased by 2.7 and 2.9% respectively, also the concentration of the CO and HC emissions have significantly decreased when biodiesel was used. An artificial neural network (ANN) was developed based on the collected data of this work. Multi layer perceptron network (MLP) was used for nonlinear mapping between the input and the output parameters. Different activation functions and several rules were used to assess the percentage error between the desired and the predicted values. The results showed that the training algorithm of Back Propagation was sufficient enough in predicting the engine torque, specific fuel consumption and exhaust gas components for different engine speeds and different fuel blends ratios. It was found that the R2 (R: the coefficient of determination) values are 0.99994, 1, 1 and 0.99998 for the engine torque, specific fuel consumption,CO and HC emissions, respectively

Combustion of microalgae oil and ethanol blended with diesel fuel

Using renewable oxygenated fuels such as ethanol is a proposed method to reduce diesel engine emission. Ethanol has lower density, viscosity, cetane number and calorific value than petroleum diesel (PD). Microalgae oil is renewable, environmentally friendly and has the potential to replace PD. In this paper, microalgae oil (10%) and ethanol (10%) have been mixed and added to (80%) diesel fuel as a renewable source of oxygenated fuel. The mixture of microalgae oil, ethanol and petroleum diesel (MOE20%) has been found to be homogenous and stable without using surfactant. The presence of microalgae oil improved the ethanol fuel demerits such as low density and viscosity. The transesterification process was not required for oil viscosity reduction due to the presence of ethanol. The MOE20% fuel has been tested in a variable compression ratio diesel engine at different speed. The engine test results with MOE20% showed a very comparable engine performance of in-cylinder pressure, brake power, torque and brake specific fuel consumption (BSFC) to that of PD. The NOx emission and HC have been improved while CO and CO2 were found to be lower than those from PD at low engine speed

Design and development of mild combustion burner

This paper discussed the design and development of the Moderate and Intense Low oxygen Dilution (MILD) combustion burner using Computational Fluid Dynamics (CFD) simulations. The CFD commercial package was used to simulate preliminary designs for the burner before the final design was sent to workshop for the fabrication. The burner is required to be a non-premixed and open burner. To capture and use the exhaust gas, the burner was enclosed within a large circular shaped wall with an opening at the top. An external EGR pipe was used to transport the exhaust gas which was mixed with the fresh oxidant. To control the EGR and exhaust flow, butterfly valves were installed at the top opening as a damper to close the exhaust gas flow at the certain ratio for EGR and exhaust out to atmosphere. High temperature fused silica glass windows were installed to view and capture images of the flame and analyse the flame propagation. The burner simulation shows that MILD combustion was achieved for the oxygen mole fraction between 3-13%. The final design of the burner was fabricated and ready for the experimental validation

Energy conversion efficiency of pulsed ultrasound

Energy characterization of a pulsed ultrasonic system was carried out using a modified calorimetric method. Sonochemical efficiency (SE) for the oxidation of Fe+2 and the formation of H2O2 was determined for selected on:off ratios (R) and different power levels. The measured efficiency of the pulsed ultrasonic system of 60-70% in converting electrical energy into calorimetric energy was found to be constant for all Rratios and equivalent to that for continuous operation. SE of Fe+2 and H2O2 for pulsed ultrasound was higher than that of continuous ultrasound. The ratio R=0.2:0.1 had the highest SE values overall, while for long off-timeratios,R=0.1:0.6 recorded the highest value of SE. These results were supported by the production rates results for Fe+2 and H2O2

Experimental and numerical investigation of spray characteristics of butanol-diesel blends

Spray characteristics are among the most important factors that affect compression ignition (CI) engines’ performance and emission levels. Flow visualisation and optical diagnostics have been widely employed in previous and current research as methods for controlling the combustion processes. This paper investigates the spray visualisation of butanol-diesel blends to determine spray characteristics such as spray penetration (S) and Average Sauter Mean Diameter (ASMD) using Ansys Forte under different ambient pressures and temperatures. The spray results showed that the spray penetration length is decreased as a result of the increased ambient pressure, while it is increased as a result of increased injection pressure of all test fuels. An increase in ambient temperature caused pure diesel penetration to become longer and wider, while butanol-diesel blends penetration becomes shorter. The ASMD of the butanol-diesel blend is higher than that of pure diesel at all operating conditions

The effect of butanol-acetone mixture-cottonseed biodiesel blend on spray characteristics, engine performance and emissions in diesel engine

Increasing energy demands and more stringent legislation relating to pollutants such as nitrogen oxide (NOx) and particulate matter (PM) from mineral fuels used in diesel engines have encouraged the use of biodiesel. Biodiesel fuels produced from non-edible oils have properties comparable to diesel fuel, which make them promising alternative fuels. However, there are some drawbacks associated with biodiesel as fuel for compression-ignition (CI) engines such as high viscosity and higher NOx emissions. Using an alcohol butanol-acetone (BA) or acetone-butanol-ethanol (ABE) mixture is one solution to improve blend efficiency and also to lower NOx emissions. The aim of this paper is to investigate the impact of a BA or ABE mixture blended with cottonseed biodiesel on spray characteristics, engine performance (in-cylinder pressure, brake power (BP) and specific fuel consumption (SFC)) and emission levels (NOx and carbon monoxide (CO)). The results demonstrated that BA and ABE decreased biodiesel viscosity and resulted in improved spray characteristics. BP was reduced while SFC was increased. The peak in-cylinder pressure was comparable at a lower engine speed while being slightly lower at 2000 rpm. The maximum reduction in NOx and CO was shown to be from 10BA90Bd by 13.84% and 41.5% respectively at 2000 rpm

The impact of injector hole diameter on spray behaviour for butanol-diesel blends

Optimising the combustion process in compression ignition (CI) engines is of interest in current research as a potential means to reduce fuel consumption and emission levels. Combustion optimisation can be achieved as a result of understanding the relationship between spraying technique and combustion characteristics. Understanding macroscopic characteristics of spray is an important step in predicting combustion behaviour. This study investigates the impact of injector hole diameter on macroscopic spray characteristics (spray penetration, spray cone angle, and spray volume) of butanol-diesel blends. In the current study, a Bosch (0.18 mm diameter) and a Delphi (0.198 mm) injector were used. Spray tests were carried out in a constant volume vessel (CVV) under different injection conditions. The test blends were injected using a solenoid injector with a common rail injection system and images captured using a high-speed camera. The experimental results showed that the spray penetration (S) was increased with larger hole diameter. Spray penetration of a 20% butanol-80% diesel blend was slightly further than that of neat diesel. Spray penetration of all test fuels was increased as a result of increased injection pressure (IP), while spray cone angle (θ) was slightly widened due to the increase in either hole diameter or injection pressure. Spray volume of all test fuels was increased as a result of increased hole diameter or injection pressure. Thus, an efficient diesel engine performance can be achieved as a result of controlling injection characteristics, especially when using a promising additive like butanol blended with diesel