Talal Yusaf

Processing of composites using variable and fixed frequency microwave facilities

[Abstract]: This paper starts with the characteristics and advantages of microwaves processing. The shortcomings of fixed frequency, typically at 2.45 GHz were also mentioned. On account of this, the newly developed variable frequency microwave (VFM) fabrication was mentioned and adopted in place of the fixed frequency process. Three cases of fixed frequency microwave processing of materials were described; the characteristics and pros of each case was mentioned and commented. Four cases of processing materials using variable frequency microwave facility (VFMF) were mentioned; the advantages and limitations of each case were discussed. The microwave processing of materials provides improved mechanical, physical and electrical properties with much reduced processing time. Furthermore, variable frequency microwave processing is more superior to its fixed frequency counterpart except that the cost of the facilities of the former is much higher than the latter at this point in time but it appears that the price will drop in the coming ten years.

Experimental investigation of a single cylinder diesel engine as a hybrid power unit for a series hybrid electric vehicle

Performance and emission testing, for a single cylinder, four-stroke diesel engine, have been experimentally performed to determine the optimum operation conditions for this engine when used as a hybrid power unit (HPU). The studied operation parameters included; Brake Specific Fuel Consumption (BSFC), exhaust emission (NO/sub x/, CO, CO/sub 2/ and O/sub 2/) and engine life. The results indicate that the lowest BSFC of the engine is found when the engine runs around 1 kW charging load when the engine speed ranged between 1900 rpm-2700 rpm. As the speed of the engine is maintained constant, the minimum level of BSFC is below 300 g/kW.hr at around 1900 rpm. The engine best operation conditions, for low emission, are found at engine speed around 2500 rpm. It was found that the oxides of nitrogen remain within the acceptable level (below 180 ppm) for such a diesel engine.

Theoretical and experimental investigation of SI engine performance and exhaust emissions using ethanol-gasoline blended fuels

In this study, potato waste bioethanol was evaluated as an alternative fuel for gasoline engines. The pollutant emissions and performance of a four stroke SI engine operating on ethanol-gasoline blends has been investigated experimentally and theoretically. In the theoretical study, a quasi-dimensional SI engine cycle model has been adapted for spark ignition engines running on gasoline-ethanol blends. A mathematical model using Matlab software was developed using the first law of thermodynamics and conservation equations to predict the SI engine performance for different blend ratios. The model was also used to evaluate the engine emissions and the mechanical and heat losses in the engine which is not included in this study. Experiments were performed with the blends containing 5, 10, 15 and 20 vol% ethanol. The results show that increasing ethanol-gasoline blended will marginally increase the power and torque output of the engine. For ethanol blends it was found that the brake specific fuel consumption (bsfc) was decreased using 5% and 10% ethanol while the brake thermal efficiency and the volumetric efficiency were increased. Exhaust gas emissions were measured and analyzed for unburned hydrocarbons (UHC), carbon dioxide (CO2), carbon monoxide (CO), Oxygen (O2) and Oxide of Nitrogen NOx at engine speeds ranging from 1000 to 5000 rpm. The concentration of CO and UHC emissions in the exhaust pipe were found to be decreased when ethanol blends were introduced. The concentration of CO2 and NOx was found to be increased when ethanol is introduced. Results obtained from both theoretical and experimental studies were compared. The simulation results have been validated against data from experiments and it results to a good agreement between the trends in the predicted and experimental results.

Energy characterisation of ultrasonic systems for industrial processes

Obtaining accurate power characteristics of ultrasonic treatment systems is an important step towards their industrial scalability. Calorimetric measurements are most commonly used for quantifying the dissipated ultrasonic power. However, accuracy of these measurements is affected by various heat losses, especially when working at high power densities. In this work, electrical power measurements were conducted at all locations in the piezoelectric ultrasonic system equipped with ½″ and ¾″ probes. A set of heat transfer calculations were developed to estimate the convection heat losses from the reaction solution. Chemical dosimeters represented by the oxidation of potassium iodide, Fricke solution and 4-nitrophenol were used to chemically correlate the effect of various electrical amplitudes and treatment regimes. This allowed estimation of sonochemical-efficiency (SE) and energy conversion (XUS) of the ultrasonic system. Results of this study showed overall conversion efficiencies of 60-70%. This correlated well with the chemical dosimeter yield curves of both organic and inorganic aqueous solutions. All dosimeters showed bubble shielding and coalescence effects at higher ultrasonic power levels, less pronounced for the ½″ probe case. SE and XUS values in the range of 10(-10) mol/J and 10(-3) J/J respectively confirmed that conversion of ultrasonic power to chemical yield declined with amplitude.

Impact of pulsed ultrasound on bacteria reduction of natural waters

There is a limited work on the use of pulsed ultrasound for water disinfection particularly the case of natural water. Hence, pulsed ultrasound disinfection of natural water was thoroughly investigated in this study along with continuous ultrasound as a standard for comparison. Total coliform measurements were applied to evaluate treatment efficiency. Factorial design of 2(3) for the tested experimental factors such as power, treatment time and operational mode was applied. Two levels of power with 40% and 70% amplitudes, treatment time of 5 and 15 min and operational modes of continuous and pulsed with On to Off ratio (R) of 0.1:0.6 s were investigated. Results showed that increasing power and treatment time or both increases total coliform reduction, whereas switching from continuous to pulsed mode in combination with power and treatment time has negative effect on total coliform reduction. A regression model for predicting total coliform reduction under different operating conditions was developed and validated. Energy and cost analyses applying electrical and calorimetric powers were conducted to serve as selection guidelines for the choosing optimum parameters of ultrasound disinfection. The outcome of these analyses indicated that low power level, short treatment time, and high R ratios are the most effective operating parameters.

Identifying the optimum process parameters for ultrasonic cellular disruption of e. coli

Abstract The aim of this work is to identify the optimum process parameters of sonication, manosonication and thermosonication for deactivating E. coli ATCC 25922 in water-based suspension. The influence of ultrasonic intensity, frequency, pressure, temperature and treatment time on the efficiency of ultrasonic treatments was investigated in this study theoretically and experimentally. The theoretical part of this study involved solving the Rayleigh-Plesset equation with different parameters and evaluating their effects on the collapse pressure of a bubble with initial radius of 0.01mm. The experimental part of the work was conducted using ultrasonic horn reactor at three levels of intensities; low (17.56 W/cm2), intermediate (21.49 W/cm2) and high (24.17 W/cm2) with fixed frequency. Thermosonication and manosonication experiments were conducted at the sub-lethal temperatures of E. coli; 45, 50, 55 and 60°C and pressures of 2, 3 and 4 bars. The optimum treatment conditions of sonication, manosonication and thermosonication were evaluated through calculating the specific energy required to obtain 5 log reduction of E. coli in each treatment. Thermosonication treatment at 21.49W/cm2 and 45°C for 4 minutes was found to be the optimum treatment conditions to deactivate E. coli in water-based suspension.

Investigating the feasibility and the optimal location of pulsed ultrasound in surface water treatment schemes

AbstractThe deterioration of surface water quality due to extreme weather events and increasing human activities has exacerbated the common problems in drinking water production such as filtration fouling and DPBs formation. This in turn has urged for exploring alternative methods for the traditional treatment methods that are able to improve the removal of contaminants with minimal impact on environment and human health. In this study, the application of pulsed and continuous ultrasound for improving the quality of natural water with fresh natural organic matter (NOM) mainly driven from vegetation has been evaluated. The evaluation was performed using cost-effective and quick measurements such as specific UV–vis absorbance, CODMn, alkalinity and conductivity. The changes in the characteristics of NOM induced by ultrasound were used to develop a framework for evaluating ultrasound performance in improving conventional surface water treatment processes and to identify the best fit of ultrasound within the ...

An Assessment of Direct on-Farm Energy Use for High Value Grain Crops Grown under Different Farming Practices in Australia

I use energy cost share to characterize the role of energy in the economy. Specifically, I use an estimate of monetary expenditures for primary energy on an annualized basis for forty-four countries from 1978 to 2010 for natural gas, coal, petroleum, and electricity. I show that global energy cost share is significantly correlated to a one-year lag in the change in gross domestic product as well as measures of total factor productivity. Given the historical reduction in the relative cost of energy (including food and fodder for animate power) since the start of the Industrial Revolution, combined with a global energy cost share estimate, I conclude that the turn of the 21st Century represents the time period with the cheapest energy in the history of human civilization (to date). This potential historical nadir for energy expenditures around 2000 has important ramifications for strategies to solve future social, economic, and environmental problems such as reducing annual emissions of greenhouse gases (GHGs). Rapidly decreasing annual GHG emissions while internalizing their costs into the economy might feedback to increase energy expenditures to such a degree as to prevent economic growth during that transition.

ADHESIVE WEAR AND FRICTIONAL BEHAVIOR OF MULTILAYERED POLYESTER COMPOSITE BASED ON BETELNUT FIBER MATS UNDER WET CONTACT CONDITIONS

In the current study, a multilayered polyester composite based on betelnut fiber mats is fabricated. The adhesive wear and frictional performance of the composite was studied against a smooth stainless steel at different sliding distances (0–6.72 km) and applied loads (20–200 N) at 2.8 m/s sliding velocity. Variations in specific wear rate and friction coefficient were evaluated at two different orientations of fiber mat; namely parallel (P–O) and normal (N–O). Results obtained were presented against sliding distance. The worn surfaces of the composite were studied using an optical microscope. The effect of the composite sliding on the stainless steel counterface roughness was investigated. The results revealed that the wear performance of betelnut fiber reinforced polyester (BFRP) composite under wet contact condition was highly dependent on test parameters and fiber mat orientation. The specific wear rate performance for each orientation showed an inverse relationship to sliding distance. BFRP composite in N–O exhibited better wear performance compared with P–O. However, the friction coefficient in N–O was higher than that in P–O at lower range of applied load. The predominant wear mechanism was debonding of fiber with no pullout or ploughing. Moreover, at higher applied loads, micro- and macrocracking and fracture were observed in the resinous region.

Nutrient removal of nursery and municipal wastewater using Chlorella vulgaris microalgae for lipid extraction

AbstractMicroalgae grown in wastewater media can not only be exploited for the nutrient removal from the wastewater, but also for the production of biofuels. In this paper, we investigated the growth of Chlorella vulgaris in iceberg lettuce nursery and municipal wastewater in a batch reactor. We analyzed the microalgal growth rate, nutrient removal rate and lipid production along with real-time monitoring of pH and dissolved oxygen (DO) dynamics during the culture period, which is rarely reported. was found to be the preferred form of nitrogen among different species of nitrogen for the growth of microalgae, and total specific nitrogen depletion rates of 33.0 and 39.6 mg TN/gSS/d were observed for nursery and municipal wastewater, respectively. The specific phosphate removal rates were 3.4 and 10.8 mg  /gSS/d for nursery and municipal wastewater, respectively. The algal growth in nutrient-rich media resulted in increase in pH and DO concentration concurrently. The online measurements including pH and DO p...