Engineering Commons^™

Coupled Air-Water Flow Through Fractured Sandstones, Buddhima Indraratna, P Ranjith

Buddhima Indraratna

In two-phase flow within a rock mass, where both air and water phases flow together, the accurate flow measurement of each individual phase is important in numerical analyses. The increased quantity of water phase decreases the relative permeability of the air phase, and vice versa. The relative permeability is important to analyse the risk of groundwater inundation and gas outbursts particularly in underground excavations. Two-phase flow (i.e., water and air) behaviour through naturally and artificially fractured standard rock cores is investigated using the high-pressure triaxial equipment developed by the authors. Findings of this study show that the individual flow rate …

Analytical Solutions For A Single Vertical Drain With Time-Dependent Vacuum Combined Surcharge Preloading In Membrane And Membraneless Systems, Xueyu Geng, Buddhima Indraratna, Cholachat Rujikiatkamjorn

Buddhima Indraratna

Vertical drains combined with vacuum pressure and surcharge preloading are widely used to accelerate the consolidation process of soft clay in order to decrease the pore pressure as well as to increase the effective stress. Currently there are two types of vacuum preloading systems commercially available; (a) membrane system with an airtight membrane over the drainage layer and, (b) membraneless system where a vacuum system is connected to individual drain. Their effectiveness varies from site to site depending on the type of soil treated and the characteristics of the drain-vacuum system. This study presents the analytical solutions of vertical drains …

Experimental And Numerical Modeling Of Shear Behaviour Of Rock Joints, Buddhima Indraratna, A Haque

Buddhima Indraratna

The shear behaviour of soft rock joints is investigated in laboratory under both Constant Normal Load (CNL) and Constant Normal Stiffness (CNS) conditions. The laboratory behaviour is modelled numerically using the Universal Distinct Element Code (UDEC). The predicted shear stress, normal stress and dilation behaviour with shear displacements are compared with the laboratory results. It is observed that UDEC can predict the peak shear stress of unfilled joints under CNS, however, it overestimates the joint dilation as well as the normal stress. The maximum peak shear stress in UDEC is attained at a greater shear displacement in contrast to the …

Performance Of A Prb For The Remediation Of Acidic Groundwater In Acid Sulfate Soil Terrain, Buddhima Indraratna, Gyanendra Regmi, Long Nghiem, A. Golab

Buddhima Indraratna

Contaminated groundwater resulting from pyrite oxidation of acid sulfate soils (ASSs) is a major environmental problem in coastal Australia. A column test was carried out for an extended period with recycled concrete to study the efficiency of the reactive materials for neutralizing acidic groundwater. Results show that the actual acid neutralization capacity of the recycled concrete could decrease to less than 50% of the theoretical value due to armoring effects. Nevertheless, the performance is good as a spot treatment in ASS Terrain using a near-zero cost waste product. Based on the test results and site characterization, a permeable reactive barrier …

Use Of Geosynthetics In Railways Including Geocomposites And Vertical Drains, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Sanjay Nimbalkar

Buddhima Indraratna

Australia relies heavily on rail for the transportation of bulk commodities and passenger services, and has introduced faster and heavier trains in recent years due to a growing demand. Large cyclic loading from heavy haul and passenger trains often leads to progressive deterioration of the track. The excessive deformations and degradations of the ballast layer and unacceptable differential settlement or pumping of underlying soft and compressible subgrade soils necessitate frequent costly track maintenance works. A proper understanding of load transfer mechanisms and their effects on track deformations are essential prerequisites for minimising maintenance costs. The reinforcement of the track by …

Effective Remediation Of Groundwater In Acid Sulphate Soil Terrain, Gyanendra Regmi, Buddhima Indraratna, Long Nghiem

Buddhima Indraratna

Acidic groundwater, generated from acid sulphate soil (ASS) is a major geo-environmental problem in Australia. Manipulation of groundwater through the use of weirs and gates in the nearby creeks and drains of ASS, which is being practised right now for preventing pyrite oxidation, are not effective in low land floodplains due to the risk of flooding. The application of permeable reactive barrier (PRB) can be a novel alternative for remediation of acidic groundwater in such floodplains. Laboratory column experiments were carried out prior to installation of the PRB for examining the efficiency of the material. Results of these experiments have …

Stabilization Of An Erodible Soil Using A Chemical Admixtures, Buddhima Indraratna, M.A.A Mahamud, J S. Vinod, Vasantha Wijeyakulasuriya

Buddhima Indraratna

This paper presents internal erosion behaviour of an erodible soil stabilized by chemical admixtures using a novel Process Simulation Apparatus for Internal Crack Erosion (PSAICE), designed and built at University of Wollongong. Laboratory tests were carried out on typical erodible soils (collected from Wombeyan caves, Australia) stabilised using chemical admixtures such as lignosulfonate and cement. Test results reveal that the erosion parameters such as critical shear stress and coefficient of soil erosion were improved with the increase in the amount of chemicals. It has been seen that lignosulfonate exhibits better performance in stabilizing the erodible soil compared to cement. Based …

Ground Improvement/Grouting/Dredging, Buddhima Indraratna

Buddhima Indraratna

Due to the rapid increase in population, industrial and construction boom especially in the urban as well as coastal regions of many countries have considerably intensified the inevitable need for infrastructure development on problematic soils including soft compressible clays, deposits with low bearing capacities, soils prone to erosion and collapse upon wetting, highly fractured and jointed rock mass among other geological deposits. Good quality geologic materials for construction are also becoming scarce, exacerbated by numerous environmental constraints in various countries. Due to these reasons and environmental restrictions on certain public works, ground improvement has now become an integrated and essential …

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 …

Investigation On Effectiveness Of A Prefabricated Vertical Drain During Cyclic Loading, Buddhima Indraratna, Jing Ni, Cholachat Rujikiatkamjorn

Buddhima Indraratna

The effectiveness of prefabricated vertical drains (PVDs) in enhancing the stability of soft soils during cyclic loading was investigated using triaxial cyclic loading tests. Both undrained and with PVD tests were employed to study the associated excess pore pressure and accumulated strain under the repeated loading condition. The loading frequency and cyclic stress ratio have been chosen to be the variables which influence the performance of soft clays. The experimental results illustrate that with PVDs, the excess pore water pressure generation during cyclic loading decreases significantly. It is found that the excess pore water pressure build up depends on both …

Internal Erosional Behaviour Of Lignosulfonate Treated Dispersive Clay, J S. Vinod, Buddhima Indraratna, M A. A Mahamud

Buddhima Indraratna

Internal erosional behaviour of lignosulfonate treated dispersive clay has been studied using the Process Simulation Apparatus for Internal Crack Erosion (PSAICE) designed and built at UOW. Effectiveness of lignosulfonate treated dispersive clay on the erosion resistance has been investigated and its advantage over traditional admixtures is presented. Test results show that the hydraulic shear stress increases with increase in the amount of lignosulfonate. In addition, the micro-chemical analysis has been carried out using FTIR. Based on the Fourier Transform Infrared (FTIR) Spectroscopy results a stabilization mechanism has been proposed for lignosulfonate treated dispersive soil.

A Multi-Staged Management Strategy For Restoring Tidal Flushing, William Glamore, Buddhima Indraratna

Buddhima Indraratna

Tidal restoration/wetland rehabilitation projects are being undertallimitations, this paper presents a tidal restoration/floodgate manipulation strategy that was developed from a four-year field study undertaken in southeastern NSW and subsequently applied at multiple field sites. An eight stage methodology is proposed to incorporate water quality, hydraulics, groundwater/saline intrusion, hydrology, field monitoring and flood design criteria. The strategy begins with a quantification of perceived outcomes for the study. Using these goals, the potential improvement in water quality are calculated using ion association models and field sampling techniques. The third stage quantifies the spatial flooding extent using GIS spatial analysis methods. The risks …

Finite Element Simulation Of Mandrel Penetration In A Normally Consolidated Soil, Cholachat Rujikiatkamjorn, Ali Ghandeharioon, Buddhima Indraratna

Buddhima Indraratna

In this paper, a finite element simulation of the mandrel penetration in normally consolidated soils is presented using a commercial finite element code (ABAQUS). A coupled analysis with large-strain frictional contact is used to simulate the soil-mandrel interface during mandrel penetration. The modified Cam clay model is used to represent the soft soil. The numerical predictions are then compared with the results obtained from the large scale laboratory tests to predict the extent of the smear zone. A large scale consolidation test was conducted with the rate-controlled device used to install the mandrel. The associated excess pore pressures at various …

The Impact Of Floodgate Modifications On Water Quality In Acid Sulphate Soil Terrains, William Glamore, Buddhima Indraratna

Buddhima Indraratna

The installation of one-way tidal restricting floodgates in regions containing acid sulphate soils has increased the problems associated with acid drainage in many areas of coastal Australia. In southeastern NSW, one-way flap gates installed in deep flood mitigation drains maintain a low groundwater table and increase acid production and transport. Moreover, by restricting the intrusion of brackish water into the drainage system, the floodgates create a reservoir of acidic water. Recent studies suggest that by allowing a controlled amount of brackish water into the drains, via modified floodgates, buffering agents can neutralize the acidic water. A fifteen-month study was undertaken …

Use Of Geosynthetics For Stabilizing Recycled Ballast In Railway Track Substructures, Buddhima Indraratna, Mohamed A. Shahin, Wadud Salim

Buddhima Indraratna

Traditional ballasted railway track substructure usually consists of graded layers of granular media of ballast and subballast (capping) placed above a compacted subgrade (formation soil). Ballast particles breakdown and deteriorate progressively under heavy train cyclic loading. Breakage of ballast is always associated with railway track deformation, which requires costly regular track maintenance in the form of replacing the degraded (recycled) ballast with fresh aggregates and subsequent re-compaction (tamping). In this paper, the use of geosynthetics for improving the deformation and degradation characteristics of recycled ballast is investigated. The prospective use of three different types of geosynthetics (i.e. geogrid, geotextile, and …

Pso Based Optimal Placement And Setting Of Facts Devicesfor Improving The Performance Of Power Distribution System, Tibin Joseph

Tibin Joseph

No abstract provided.

A Benchmark Study On The Thermal Conductivity Of Nanofluids, Jacopo Buongiorno, David C. Venerus, Naveen Prabhat, Thomas Mckrell, Jessica Townsend, Rebecca J. Christianson, Yuriv V. Tolmachev, Pawel Keblinski, Lin-Wen Hu, Jorge L. Alvarado, In Cheol Bang, Sandra W. Bishnoi, Marco Bonetti, Frank Botz, Anselmo Cecere, Yun Chang, Gang Chen, Haisheng Chen, Sung Jae Chung, Minking K. Chyu, Sarit K. Das, Roberto Di Paola, Yulong Ding, Frank Dubois, Grzegorz Dzido, Jacob Eapen, Werner Escher, Denis Funfschilling, Quentin Galand, Jinwei Gao, Patricia E. Gharagozloo, Kenneth E. Goodson, Jorge Gustavo Gutierrez, Haiping Hong, Mark Horton, Kyo Sik Hwang, Carlo S. Iorio, Seok Pil Jang, Andrzej B. Jarzebski, Yiran Jiang, Stephan Kabelac, Liwen Jin, Aravind Kamath, Mark A. Kedzierski, Lim Geok Kieng, Chongyoup Kim, Ji-Hyun Kim, Seokwon Kim, Seung Hyun Lee, Kai Choong Leong, Indranil Manna, Bruno Michel, Rui Ni, Hrishikesh E. Patel, John Philip, Dimos Poulikakos, Cecil Reynaud, Raffaele Savino, Pawan K. Singh, Pengxiang Song, Thirumalachari Sundararajan, Elena Timofeeva, Todd Tritcak, Aleksandr N. Turanov, Stefan Van Vaerenbergh, Dongsheng Wen, Sanjeeva Witharana, Chun Yang, Wei-Hsun Yeh, Xiao-Zheng Zhao, Sheng-Qi Zhou

Jessica Townsend

This article reports on the International Nanofluid Property Benchmark Exercise, or INPBE, in which the thermal conductivity of identical samples of colloidally stable dispersions of nanoparticles or “nanofluids,” was measured by over 30 organizations worldwide, using a variety of experimental approaches, including the transient hot wire method, steady-state methods, and optical methods. The nanofluids tested in the exercise were comprised of aqueous and nonaqueous basefluids, metal and metal oxide particles, near-spherical and elongated particles, at low and high particle concentrations. The data analysis reveals that the data from most organizations lie within a relatively narrow band (±10% or less) about …

A Benchmark Study On The Thermal Conductivity Of Nanofluids, Jacopo Buongiorno, David Venerus, Naveen Prabhat, Thomas Mckrell, Jessica Townsend, Rebecca Christianson, Yuriv Tolmachev, Pawel Keblinski, Lin-Wen Hu, Jorge Alvarado, In Cheol Bang, Sandra Bishnoi, Marco Bonetti, Frank Botz, Anselmo Cecere, Yun Chang, Gang Chen, Haisheng Chen, Sung Jae Chung, Minking Chyu, Sarit Das, Roberto Di Paola, Yulong Ding, Frank Dubois, Grzegorz Dzido, Jacob Eapen, Werner Escher, Denis Funfschilling, Quentin Galand, Jinwei Gao, Patricia Gharagozloo, Kenneth Goodson, Jorge Gutierrez, Haiping Hong, Mark Horton, Kyo Sik Hwang, Carlo Iorio, Seok Pil Jang, Andrzej Jarzebski, Yiran Jiang, Stephan Kabelac, Liwen Jin, Aravind Kamath, Mark Kedzierski, Lim Geok Kieng, Chongyoup Kim, Ji-Hyun Kim, Seokwon Kim, Seung Hyun Lee, Kai Choong Leong, Indranil Manna, Bruno Michel, Rui Ni, Hrishikesh Patel, John Philip, Dimos Poulikakos, Cecil Reynaud, Raffaele Savino, Pawan Singh, Pengxiang Song, Thirumalachari Sundararajan, Elena Timofeeva, Todd Tritcak, Aleksandr Turanov, Stefan Van Vaerenbergh, Dongsheng Wen, Sanjeeva Witharana, Chun Yang, Wei-Hsun Yeh, Xiao-Zheng Zhao, Sheng-Qi Zhou

Rebecca J. Christianson

This article reports on the International Nanofluid Property Benchmark Exercise, or INPBE, in which the thermal conductivity of identical samples of colloidally stable dispersions of nanoparticles or “nanofluids,” was measured by over 30 organizations worldwide, using a variety of experimental approaches, including the transient hot wire method, steady-state methods, and optical methods. The nanofluids tested in the exercise were comprised of aqueous and nonaqueous basefluids, metal and metal oxide particles, near-spherical and elongated particles, at low and high particle concentrations. The data analysis reveals that the data from most organizations lie within a relatively narrow band (±10% or less) about …

Modeling All Spin Logic: Multi-Magnet Networks Interacting Via Spin Currents, Srikant Srinivasan

Srikant Srinivasan

All-spin logic (ASL) represents a new approach to information processing where the roles of charges and capacitors in CMOS are played by spins and magnets. This paper (1) summarizes our earlier work on the input-output isolation and intrinsic directivity of ASL devices, (2) uses an experimentally benchmarked simulator for multimagnet networks coupled by spin transport channels to demonstrate a combinational NAND gate, and (3) describes the natural mapping of such ASL networks into neuromorphic circuits suitable for hybrid analog/digital information processing.

New Frontiers In Ocean Exploration: The 2011 E/V Nautilus Field Season, K. Bell, R. Ballard, D. Coleman, C. Roman, M. Brennan, T. Turanli, M. Duman, S. Carey, P. Nomikou, M. Marani, M. Rosi, J. Austin, M. Canals, J. Karson, L. Mayer, Y. Makovsky

Christopher N. Roman

In the summer of 2011, the Exploration Vessel NAUTILUS is undertaking a four-month expedition to the Black, Aegean and Mediterranean Seas, and North Atlantic Ocean. The primary goal of the NAUTILUS is to create a focus of international leadership for the development and integration of leading-edge technologies, educational programs, field operations, and public outreach programs for ocean exploration, in partnership with NOAA, National Geographic Society, Office of Naval Research, and other sponsors. To do so, the program uses a complement of deep submergence vehicle systems and “telepresence” technologies to engage scientists, educators and the public, both at sea and ashore, …

High Resolution Sea Floor Bathymetry Using High Frequency Multibeam Sonar And Structured Light Laser Imaging, C. Roman, G. Inglis, C. Smart, I. Vaughn, S. Carey

Christopher N. Roman

Detailed bathymetric maps of the sea floor with centimeter level resolution can be produced by underwater vehicles using multibeam sonars and structured light laser imaging. Over spatial scales up to tens of thousands of square meters it is possible to produce maps gridded to sub centimeter levels. This level of accuracy demands detailed treatments of the sensor relative data, the vehicle navigation data and the vehicle to sensor position and rotational offsets. The presented results will show comparisons between these two sensor modalities. Data have a been collected during recent field programs to the Kolumbo volcanic crater and the Southern …

Remote Analysis Of Grain Size Characteristic In Submarine Pyroclastic Deposits From Kolumbo Volcano, Greece, C. Smart, D. P. Whitesell, C. Roman, S. Carey

Christopher N. Roman

Grain size characteristics of pyroclastic deposits provide valuable information about source eruption energetics and depositional processes. Maximum size and sorting are often used to discriminate between fallout and sediment gravity flow processes during explosive eruptions. In the submarine environment the collection of such data in thick pyroclastic sequences is extremely challenging and potentially time consuming. A method has been developed to extract grain size information from stereo images collected by a remotely operated vehicle (ROV). In the summer of 2010 the ROV Hercules collected a suite of stereo images from a thick pumice sequence in the caldera walls of Kolumbo …

Detection Of Diffuse Sea Floor Venting Using Structured Light Imaging, G. Inglis, C. Smart, C. Roman, S. Carey

Christopher N. Roman

Efficiently identifying and localizing diffuse sea floor venting at hydrothermal and cold seep sites is often difficult. Actively venting fluids are usually identified by a temperature induced optical shimmering seen during direct visual inspections or in video data collected by vehicles working close to the sea floor. Relying on such direct methods complicates establishing spatial relations between areas within a survey covering a broad area. Our recent work with a structured light laser system has shown that venting can also be detected in the image data in an automated fashion. A structured light laser system consists of a camera and …

Solving Virus Problems By System Administrators- A Triz Perspective, Umakant Mishra

Umakant Mishra

The computer virus is not only a problem to the end user but also a problem to everybody whoever is associated with computers, including systems administrators, corporate managers and even anti-virus manufacturers. In the previous article we discussed on how to use TRIZ for analyzing and solving virus problems of an end user. In this article we will focus on the problems faced by the systems administrators.

An analysis of virus scenario finds that the same situation of virus infection creates different problems to people at different levels, such as, a computer user, a system administrator, a corporate manager and …

Solving Virus Problems By Computer Users- A Triz Perspective, Umakant Mishra

Umakant Mishra

The knowledge on TRIZ helps us analyzing a problem. Analysis is an important step in problem solving because the same event may be causing different problems (or benefits) to different people under different conditions. Some solutions may be addressing a problem in a short term or narrow perspective while giving rise to other problems or disadvantages. A good solution should be ideal and holistic in approach and should lead to no other problems or negative consequences.

When we analyze the problem of computer virus we find that different types of computer users face different types of problems and seek to …

A New Method Of Producing High Strength Oil Palm Shell Lightweight Concrete, Hilmi Mahmud

Hilmi Mahmud

This paper presents a new method to produce high strength lightweight aggregate concrete (HSLWAC) using an agricultural solid waste, namely oil palm shell (OPS). This method is based on crushing large old OPS. Crushed OPS are hard and have a strong physical bond with hydrated cement paste. The 28 and 56. days compressive strength achieved in this study were about 53 and 56. MPa, respectively. Furthermore, it was observed that it was possible to produce grade 30 OPS concrete without the addition of any cementitious materials. Compared to previous studies, significantly lower cement content was used to produce this grade …

Development Of A Compression Test Device For Investigating Interaction Between Diffusion Of Biodiesel And Large Deformation In Rubber

A.S. Md Abdul Haseeb

Motivated by environmental and economic factors, biodiesel has been introduced to partially replace the diminishing stock of petroleum-based fuel. However, the use of biodiesel such as palm biodiesel is placing additional demands on automotive components, e.g. rubber components, due to a compatibility issue in the fuel system. In engineering applications where hostile environments are involved, the long-term mechanical response of rubber components is affected by interactions existed between diffusion of liquids into the material and fluctuating multiaxial loading. Hence, it is crucial to investigate the durability of rubber components in this aggressive environment. A number of studies on static immersion …

Membrane Biodiesel Production And Refining Technology: A Critical Review, Abdul Aziz Abdul Raman

Abdul Aziz Abdul Raman

Membranes processes for the production and refining of biodiesel are being increasingly reported. Membrane technology has attracted the interest of researchers for its ability to provide high purity and quality biodiesel fuel besides its remarkable biodiesel yields. Membranes have numerous numbers of useful properties such as resistance to mechanical, chemical and thermal stress, high available surface area per unit volume, high selectivity, and ability to control the components contact between the two phases makes them potential. These properties have made them to be potential candidates for both upstream and downstream biodiesel production and refining applications. In this regards, this paper …

Refining Technologies For The Purification Of Crude Biodiesel, Abdul Aziz Abdul Raman

Abdul Aziz Abdul Raman

In biodiesel production, downstream purification is an important step in the overall process. This article is a critical review of the most recent research findings pertaining to biodiesel refining technologies. Both conventional refining technologies and the most recent biodiesel membrane refining technology are reviewed. The results obtained through membrane purification showed some promise in term of biodiesel yield and quality. Also, membranes presented low water consumption and less wastewater discharges. Therefore, exploration and exploitation of membrane technology to purify crude biodiesel is necessary. Furthermore, the success of membrane technology in the purification of crude biodiesel could serve as a boost …

Improve Design For Automated Tajweed Checking Rules Engine Of Quranic Verse Recitation: A Review, Noor Jamaliah Ibrahim, Zulkifli Mohd Yusoff, Zaidi Razak

Noor Jamaliah Ibrahim

Generally, reliable speech recognition is a hard problem that required a combination solution of many techniques. Thus, the combinations of Al-Quran with speech recognition system is quite challenging task to be implemented. It is because the Quran sound, which had been recited by most of reciters will probably tend to differ a lot from one person to another. Although those Quranic sentences were particularly taken from the same verse, but the way of the sentence in Al-Quran been recited or delivered may be different, depend on reciters with the different levels of understanding of Tajweed rules. This paper seeks to …