Engineering Commons^™

Enhancement Of Trace Organic Contaminant Degradation By Crude Enzyme Extract From Trametes Versicolor Culture: Effect Of Mediator Type And Concentration, Ngoc Luong Nguyen, Faisal Ibney Hai, Jinguo Kang, Frederic Leusch, Felicity Roddick, S Faraj Magram, William Price, Long Nghiem

Faisal I Hai

The performance of two redox mediating compounds, namely 1-hydroxybenzotriazole (HBT) and syringaldehyde (SA), was compared in terms of enhancement of enzymatic degradation of a diverse set of 14 phenolic and 16 non-phenolic trace organic contaminants (TrOCs) and the toxicity of the treated media. Extracellular enzyme extract (predominantly containing laccase) from Trametes versicolor culture achieved efficient degradation (70-95%) of nine phenolic and one non-phenolic TrOCs. Mediator dosing extended the spectrum of efficiently degraded TrOCs to 13 phenolic and three non-phenolic compounds, with moderate improvements in removal of a few other non-phenolic compounds. TrOC removal efficiency improved significantly as the HBT dose …

Impact Of 1-Hydroxybenzotriazole Dosing On Trace Organic Contaminant Degradation By Laccase, Ngoc Luong Nguyen, Faisal Ibney Hai, Jinguo Kang, S Faraj Magram, William Price, Long Nghiem

Faisal I Hai

This study investigated the removal of five selected non-phenolic trace organic contaminants (TrOC) by extracellular enzyme extract from a white-rot fungus. Except diclofenac, no other investigated non-phenolic TrOC were degraded by the extracellular enzyme extract. Improvement of enzymatic degradation of all TrOC was achieved in the presence of a redox mediator, namely, 1-hydroxybenzotriazole (HBT). However, the enhancement of degradation was mediator concentration-specific. A significant improvement in degradation at higher dosage than 0.1 mM (HBT) was achieved.

Degradation Of Azo Dye Acid Orange 7 In A Membrane Bioreactor By Pellets And Attached Growth Of Coriolus Versicolour, Faisal I. Hai, Kazuo Yamamoto, Fumiyuki Nakajima, Kensuke Fukushi, Long D. Nghiem, William E. Price, Bo Jin

Faisal I Hai

The aim of this study was to systematically compare the degradation of azo dye acid orange 7 by spongy pellets and attached biofilm of Coriolus versicolour (NBRC 9791) in a membrane bioreactor (MBR) under non-sterile conditions. Mild stirring (35 rpm) resulted in spherical (φ = 0.5 cm), spongy pellets and concomitantly triggered high enzymatic activity of the fungus, allowing for excellent decolouration (>99%) of a synthetic wastewater containing the dye. However, bacterial contamination eventually damaged the fungus pellets, leading to decreased decolouration efficiency. Promotion of attached growth on a plastic support along with formation of spherical spongy pellets allowed …

Enhanced Sonocatalytic Treatment Of Ibuprofen By Mechanical Mixing And Reusable Magnetic Core Titanium Dioxide

Faculty of Engineering University of Malaya

As a reusable sonocatalyst, magnetically separable titanium dioxide (MST) was synthesized by a sol-gel method and was evaluated in the removal of ibuprofen (IBP). MST was carefully characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), N-2 gas isotherms, band-gap energy, magnetization, zeta potential, and particle size distribution. The kinetics of IBP removal by sonolysis or MST-assisted sonocatalysis was systematically evaluated with various operational parameters such as pH, temperature, ultrasound (US) frequency, and mechanical mixing intensity. For the first time, authors found that mechanical mixing had an opposite effect on the oxidation rate constants of IBP removal by sonolysis …

Stabilizing Nanostructured Solid Oxide Fuel Cell Cathode With Atomic Layer Deposition, Yunhui Gong, Diego Palacio, Xueyan Song, Rajankumar Patel, Xinhua Liang, Xuan Zhao, John Goodenough, Kevin Huang

Kevin Huang

No abstract provided.

Effect Of A Low-Molecular-Weight Cross-Linkable Macromer On Electrospinning Of Poly(Lactide-Co-Glycolide) Fibers, Weijie Xu, Xuezhong He, Alireza Sarvestani, Esmaiel Jabbari

Esmaiel Jabbari

No abstract provided.

Monte Carlo Simulation Of Degradation Of Porous Poly(Lactide) Scaffolds, I. Effect Of Porosity On Ph, Yousef Mohammadi, Esmaiel Jabbari

Esmaiel Jabbari

No abstract provided.

Nanostructure Formation And Transition From Surface To Bulk Degradation In Polyethylene Glycol Gels Chain-Extended With Short Hydroxy Acid Segments, Seyedsina Moeinzadeh, Danial Barati, Samaneh Kamali Sarvestani, Ozan Karaman, Esmaiel Jabbari

Esmaiel Jabbari

No abstract provided.

Estimation Of The Effect Of Catalyst Physical Characteristics On Fenton-Like Oxidation Efficiency Using Adaptive Neuro-Fuzzy Computing Technique

Faculty of Engineering University of Malaya

Catalyst size, which determines surface area, is one of the major factors in catalytic performance. In this study, response surface methodology (RSM) and an adaptive neuro-fuzzy inference system (ANFIS) were applied to quantify the effects of physical characteristics of magnetite on Fenton-like oxidation efficiency of methylene blue. For this purpose, two magnetite samples (M and N) were used and characterized by XRD, BET surface area, particle size analyzer and FE-SEM. Central composite design (CCD) was applied to design the experiments, develop regression models, optimize and evaluate the individual and interactive effects of five independent variables: H2O2 and catalyst concentrations, pH, …

Deformation And Degradation Of Clay Fouled Ballast Subjected To Monotonic Loading, Nayoma Tennakoon, Buddhima Indraratna, Sanjay Nimbalkar, Cholachat Rujikiatkamjorn

Cholachat Rujikiatkamjorn

Railways offer an efficient and economic transport mode in many countries including Australia, China and USA. Conventionally, rail tracks are positioned on ballast due to several potential benefits, including economy (availability and abundance), rapid drainage and high load bearing capacity. However, the ballast becomes contaminated due to intrusion of pumped subgrade material (e.g. clay and silt). This is one of the primary reasons for rapid track deterioration. In severe circumstances, fouled ballast needs to be cleaned or replaced to maintain the desired track resiliency, load bearing capacity and the track alignment, all of which influence the level of safety. In …

Stress-Strain Degradation Response Of Railway Ballast Stabilized With Geosynthetics, Buddhima Indraratna, Sanjay Nimbalkar

Buddhima Indraratna

Large cyclic loading on ballasted railroad tracks is now inevitable owing to an increased demand for freight and public transport. This leads to a progressive deterioration and densification of railroad ballast and consequently to the loss of track geometry and differential settlement. Understanding these complex stress-strain and degradation mechanisms is essential to predict the desirable track maintenance cycle, as well as the design of new track. This paper presents the results of cyclic drained tests and numerical studies carried out on a segment of model railway track supported on geosynthetically reinforced railroad ballast bed. The relative performance and effectiveness of …

Effects Of Fouling On The Stress-Strain-Degradation Behaviour Of Rail Ballast, Buddhima Indraratna, Nayoma C. Tennakoon, Sanjay Nimbalkar, Cholachat Rujikiatkamjorn

Buddhima Indraratna

Ballast is most commonly used as a structural component of rail track due to its high load bearing capacity, resiliency and rapid drainage. However, ballast along coal freight corridors often becomes fouled due to spilling of coal from moving wagons, in addition to further track deterioration attributed to particle breakage and pumping of soft subgrade. Highly fouled ballast needs to be cleaned or replaced to maintain the desired track resiliency, load bearing capacity and the track alignment. In order to identify the risk associated with fouling, it is important to accurately assess the amount of fouling. In this paper, the …

Comparison Study Of Different Ionic Liquid Pretreatments In Maximizing Total Reducing Sugars Recovery, Kiat Moon Lee, Gek Cheng Ngoh Dr, Adeline Seak May Chua Dr, Li Wan Yoon, Teck Nam Ang Dr., Min Gyu Lee Prof

Teck Nam Ang Dr.

A process scheme combining the most suitable ionic liquid pretreatment, followed by solid acid and enzymatic saccharification was used to maximize the reducing sugars recovery from sago waste. Three types of ionic liquids, i.e. 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), 1- ethyl-3-methylimidazolium acetate ([EMIM][OAc]) and 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM][(EtO)2PO2]) were evaluated based on their performance in terms of the total reducing sugars recovery, chemical cost, and pretreatment energy requirement. The results showed that all the ionic liquids assisted the saccharification processes by dissolving and depolymerizing the carbohydrates of the sago waste into shorter chain soluble oligosaccharides, as well as disrupting the biomass structure …

Critical Current Degradation Caused By Winding Process Of Bi-2223/Ag Hts Wire In The Form Of A Coil, Jian X. Jin, S X. Dou, Hua-Kun Liu, T Hardono, Christopher D. Cook, C. Grantham

Shi Xue Dou

High T, superconducting (HTS) (Bi,Pb)2Sr2Ca2 Cu3010+xA g-clad wire has potential for practical applications in the form of a coil or a winding. This HTS wire has strong magnetic field-dependent and mechanical strain-dependent critical currents, consequently it faces a severe problem of critical current degradation when it is used in the form of a coil. To design a winding with this conductor, the critical current degradation has to be identified with relation to the magnetic fields and the winding process. This is important to optimize an appropriate coil winding procedure using this HTS wire. A specially designed non-inductive sample has been …

Effects Of Membrane Degradation On The Removal Of Pharmaceutically Active Com#163s (Phacs) By Nf/Ro Filtration Processes, Alexander Simon, Long Nghiem, Pierre Le-Clech, Stuart J. Khan, Jorg E. Drewes

Long D Nghiem

The impacts of membrane degradation due to chlorine attack on the rejection of pharmaceutically active compounds (PhACs) by nanofiltration and reverse osmosis membranes were investigated in this study. Membrane degradation was simulated by soaking the membranes in a sodium hypochlorite solution of various concentrations over 18 h. Changes in membrane surface properties were characterised by contact angle measurement, atomic force microscopy analysis, and streaming potential measurement. The impacts of hypochlorite exposure to the membrane separation processes were ascertained by comparing the rejection of PhACs by virgin and chlorine-exposed membranes. Overall, the reverse osmosis BW30 membrane and the tight nanofiltration NF90 …

Critical Current Degradation Caused By Winding Process Of Bi-2223/Ag Hts Wire In The Form Of A Coil, Jian X. Jin, S X. Dou, Hua-Kun Liu, T Hardono, Christopher D. Cook, C. Grantham

Christopher Cook

High T, superconducting (HTS) (Bi,Pb)2Sr2Ca2 Cu3010+xA g-clad wire has potential for practical applications in the form of a coil or a winding. This HTS wire has strong magnetic field-dependent and mechanical strain-dependent critical currents, consequently it faces a severe problem of critical current degradation when it is used in the form of a coil. To design a winding with this conductor, the critical current degradation has to be identified with relation to the magnetic fields and the winding process. This is important to optimize an appropriate coil winding procedure using this HTS wire. A specially designed non-inductive sample has been …

Application Of A Gac-Coated Hollow Fiber Module To Couple Enzymatic Degradation Of Dye On Membrane To Whole Cell Biodegradation Within A Membrane Bioreactor, Faisal I. Hai, Kazuo Yamamoto, Fumiyuki Nakajima, Kensuke Fukushi

Faisal I Hai

Additional granular activated carbon (GAC) layers on the membrane module within a whole cell fungal membrane bioreactor (MBR) set up to treat dye wastewater was effective in minimizing enzymewashout and in improvement of decoloration (degradation of the dye). Supporting batch tests and continuous monitoring of the quality of bioreactor-supernatant and membrane-penneate revealed that biodegradation was effected by both the suspended culture and the dynamically immobilized enzyme on the GAC-coated membrane. In a control MBR. the efficiency of dye removal was variable; in contrast. 85% to near complete removal of dye was achieved using the MBRs equipped with a membrane with …

Degradation Uniformity Of Rf-Power Gaas Phemts Under Electrical Stress, Anita Villanueva, Jesus Del Alamo, Takayuki Hisaka, Kazuo Hayashi, Mark Somerville

Mark Somerville

We have studied the electrical degradation of RF-power PHEMTs by means of in situ 2-D light-emission measurements. Electroluminescence originates in the recombination of holes that have been generated by impact ionization. The local light intensity, thus, maps the electric-field distribution at the drain side of the device. This allows us to probe the uniformity of electrical degradation due to electric-field-driven mechanisms. We find that electrical degradation proceeds in a highly nonuniform manner across the width of the device. In an initial phase, degradation takes place preferentially toward the center of the gate finger. In advanced stages of degradation, the edges …

Degradation Of Mgo Refractory In Cao-Sio2-Mgo-Feox And Cao-Sio2-Al2o3-Mgo-Feox Slags Under Forced Convection, Sharon Nightingale, Geoff Brooks, Brian J. Monaghan

Brian Monaghan

Experiments based on exposure of MgO to slags under forced convection flow conditions allowed the identification of different degradation mechanisms and the assessment of the role of Al2O3 in the degradation process. Slag with no alumina present resulted in direct dissolution. Samples immersed in alumina containing slag underwent indirect dissolution, with a spinel forming at the MgO-slag interface. At 1530 °C, the spinel was not effective in reducing the corrosion rate, as the scattered spinel grains were easily removed from the MgO surface. At 1500 °C, the loss of MgO was reduced due to the formation of a more cohesive …

Deformation And Degradation Mechanics Of Recycled Ballast Stabilised With Geosynthetics, Buddhima Indraratna, Wadud Salim

Buddhima Indraratna

Railway ballast deforms and degrades progressively under heavy train (cyclic) loading. Ballast degradation is influenced by several factors including the amplitude and number of load cycles, density of aggregates, track confining pressure, angularity, and most importantly, the fracture strength of individual grains. The degraded ballast is usually cleaned on track, otherwise fully or partially replaced by fresh ballast, depending on the track settlement and current density. The disposed waste ballast may be cleaned, sieved and re-used in the track. However, due to the breakage of the sharp edges and the development of micro-cracks during the previous loading cycles, recycled ballast …

Failure Analysis Of Retrieved Uhmwpe Tibial Insert In Total Knee Replacement

A.S. Md Abdul Haseeb

This study involves the failure analysis of an ultra high molecular polyethylene (UHMWPE) tibial insert from Apollo® Total Knee System, which was removed after 10. years of service from 70. years old female patient. The tibial insert was investigated by using a stereoscope, scanning electron microscope (SEM), infinite focus microscope (IFM) and energy disperse spectroscopy (EDS) to characterize the morphology and composition of the bearing surface. Differential scanning calorimetry (DSC) and Fourier transform spectroscopy (FTIR) were employed to characterize the degradation and crystallinity of the component. Gel-permeation chromatography (GPC) was used to measure the polyethylene tibial insert molecular weight. Results …

Enhanced Biodegradation Of Used Engine Oil In Soil Amended With Organic Wastes, Abdul Aziz Abdul Raman

Abdul Aziz Abdul Raman

Three organic wastes (banana skin (BS), brewery spent grain (BSG), and spent mushroom compost (SMC)) were used for bioremediation of soil spiked with used engine oil to determine the potential of these organic wastes in enhancing biodegradation of used oil in soil. The rates of biodegradation of the oil were studied for a period of 84 days under laboratory conditions. Hydrocarbon-utilizing bacterial counts were high in all the organic waste-amended soil ranging between 10.2 x 10(6) and 80.5 x 10(6) CFU/g compared to unamended control soil throughout the 84 days of study. Oil-contaminated soil amended with BSG showed the highest …

Deterioration Of Dynamic Rail Pad Characteristics, Alexander Remennikov, Sakdirat Kaewunruen, Karl Ikaunieks

Alex Remennikov

Impact loads applied to concrete sleepers, either due to the wheel flats of a train or rail abnormalities, may cause the sleepers to crack. The rail pads have been used to attenuate the effect of these impact loads on concrete sleepers and on the substructures in ballasted railway tracks. The rail pads experience high intensity loads due to wheel impacts and, as a result, the pad properties deteriorate during the service life. The consequences can be significant for the dynamic behaviour of railway tracks, interaction of vehicle and track, and impact forces on track components. However, there is currently no …

Thermal Degradation Of Segmented Polyurethanes, William Macknight, Zoran S. Petrovic, Zoltan Zavargo, Joseph H. Flynn

William MacKnight