Magued Iskander

A Transparent Water-Based Polymer for Simulating Multiphase Flow

This study proposes a new water-based transparent material called Aquabeads for modeling flow in natural soils. Three types of this material were used to model miscible and multiphase flow transport process in layered soil systems. An optical system was set up to trace flow movements in a two-dimensional (2D) physical model of a soil profile, analyzed using digital image processing to define images of 2D concentration profiles in the model. Model surfactant flushing tests were conducted using a layered soil system and two contaminants, mineral oil and motor oil, in order to illustrate the feasibility of using this water-based polymer to visualize geoenvironmental contamination problems. A surfactant solution made of Triton X-100 mixed with sec-butanol alcohol and xanthan gum was used to achieve a recovery ratio of 88.5 % of motor oil and 95.8 % of mineral oil. Because a transparent soil is used, the optical systems allows for visualizing surfactant flushing. Addition of xanthan gum to increase viscosity prevents mineral oil’s downward migration, thus significantly enhancing the oil recovery. The increase in viscosity of the surfactant prevents motor oil from bypassing the plume, thus enhancing recovery by up to 20 times. The study demonstrates that Aquabeads are suitable for modeling multiphase flow, particularly in educational settings.

Development of a Transparent Material to Model the Geotechnical Properties of Soils

Measurement of three-dimensional deformation patterns and flow characteristics within a soil continuum are usually limited by the fact that soil sensors do not provide a continuous image of the measured continuum. Additionally, soil sensors exhibit static and dynamic characteristics that are different from those of the surrounding soils and therefore can change the response of the measured continuum. Tests conducted with a transparent material which has properties that closely model the geotechnical properties of natural soils can potentially circumvent these experimental problems if the response of a model transparent continuum can be measured using nonintrusive optical visualization techniques. This paper demonstrates the feasibility of producing transparent materials which exhibit macroscopic properties representative of the geotechnical properties of natural soils. The transparent “soils” discussed in this paper were made by consolidating suspensions of amorphous silica in liquids with matching optical refractive indices. The measured shear strengths and permeabilities of the transparent soils are characteristic of natural clays and silts. The stress-strain response of transparent soils is characterized by large strains during consolidation and shear.

Modelling capacity of transparent soil

The modelling capacity of transparent soil was investigated by comparing boundary soil displacement fields under a model footing in a transparent soil model with those from a natural soil model. Transparent soil is made of either amorphous silica gels or powders and a pore fluid with a matching refractive index to model sand and clay. An optical system consisting of a laser light, camera, frame grabber, and computer was developed to optically slice a transparent soil model. A distinctive laser speckle pattern was generated by the interaction between the laser light and transparent soil. Two laser speckle images before and after a deformation were used to calculate the displacement field using an image processing technique called digital image correlation. The comparative study shows that transparent soil can be used to study natural soil with some limitations. Transparent soil and the developed optical system could be used to explore opportunities for more advanced nonintrusive three-dimensional deformati...

Analysis of Tunneling-Induced Ground Movements Using Transparent Soil Models

Ground movements induced by shallow tunnels affect the safety of nearby underground and aboveground structures. Therefore, the reliable prediction of these movements is important. A transparent soil model is used to investigate not only the surface settlement profile induced by shield tunneling, but also the distribution of soil deformation within the soil mass near the tunnel. The observed surface settlements are consistent with the normal probability curve commonly used for predicting settlement, with only the inflection points or trough width parameters somewhat different. The measured data are consistent with field measurements in that the trough width parameter is independent of the volume loss and linearly proportional to the tunnel depth. An analysis of the displacement field inside the transparent soil models indicates that the subsurface settlement trough at different depths can be approximated by a normal probability curve; and the horizontal displacement can be expressed by the trough width parameter and the volume loss, at the point at which maximum horizontal displacement occurs at the point of inflection. Additionally, the measurements indicate that subsurface ground movements can be in excess of the observed surface settlement, which can adversely affect underground utilities.

Innovative Techniques in Instruction Technology, E-learning, E-assessment and Education

Innovative Techniques in Instruction Technology, E-Learning, E-Assessment and Education is a collection of world-class paper articles addressing the following topics: (1) E-Learning including development of courses and systems for technical and liberal studies programs; online laboratories; intelligent testing using fuzzy logic; evaluation of on line courses in comparison to traditional courses; mediation in virtual environments; and methods for speaker verification. (2) Instruction Technology including internet textbooks; pedagogy-oriented markup languages; graphic design possibilities; open source classroom management software; automatic email response systems; tablet-pcs; personalization using web mining technology; intelligent digital chalkboards; virtual room concepts for cooperative scientific work; and network technologies, management, and architecture. (3) Science and Engineering Research Assessment Methods including assessment of K-12 and university level programs; adaptive assessments; auto assessments; assessment of virtual environments and e-learning. (4) Engineering and Technical Education including cap stone and case study course design; virtual laboratories; bioinformatics; robotics; metallurgy; building information modeling; statistical mechanics; thermodynamics; information technology; occupational stress and stress prevention; web enhanced courses; and promoting engineering careers. (5) Pedagogy including benchmarking; group-learning; active learning; teaching of multiple subjects together; ontology; and knowledge representation. (6) Issues in K-12 Education including 3D virtual learning environment for children; e-learning tools for children; game playing and systems thinking; and tools to learn how to write foreign languages.

Consolidation and Permeability of Transparent Amorphous Silica

The consolidation and permeability of transparent amorphous silica are studied in this paper. Transparency is achieved by matching the refractive indices of the amorphous silica particles and the pore fluid. The fundamental premise of this research is that transparent synthetic soils made of amorphous silica can be used in model tests to study three-dimensional deformation and flow problems, using nonintrusive optical visualization techniques, if amorphous silica can be produced with geotechnical properties similar to natural soils. The amorphous silicas studied in this paper exhibit consolidation behavior similar to that of organic clays and peat. The permeability of the material falls within the range typically reported for clays and peats.

Spatial Deformation Measurement Using Transparent Soil

This paper addresses the need for nonintrusively measuring spatial deformation pattern inside soils. In this study, transparent soil surrogates are used in model tests instead of natural soils. Transparent soil with macrogeotechnical properties similar to those of natural soils was made of either transparent amorphous silica gels or powders and a pore fluid with a matching refractive index. An optical system consisting of a laser light, a line-generator lens, a charge-coupled device (CCD) camera, a frame grabber, and a computer was developed to optically slice a transparent soil model. A distinctive speckle pattern is generated by the interaction of the laser light and transparent soil. The laser speckle images before and after deformation were used to nonintrusively measure the relative displacement field using digital image cross-correlation. Spatial displacement fields under a model footing were obtained by combining several cross-sections in MATLAB®. Test results showed that the developed optical system and transparent soil are suitable for studying soil-structural interaction problems.

Geotechnical properties of sucrose-saturated fused quartz for use in physical modeling

This study presents the geotechnical properties of a synthetic transparent soil made of fused quartz saturated with a water-based sucrose solution that is suitable for modeling the behavior of sand in small-scale model tests. Geotechnical properties presented include particle size, dry density, peak angle of friction, hydraulic conductivity, and compressibility index. Sucrose is inert and non-toxic, which facilitates its use in educational settings. The availability of a safe and easy-to-use transparent sand permits measurement of three-dimensional deformation patterns and flow characteristics in controlled research experiments. The introduction of an aqueous solution permits the use of two immiscible pore fluids, one made of mineral oil and the other made of a sucrose solution, for modeling multi-phase flow problems, as well as coupled flow–deformation problems.

Past, Present, and Future of Transparent Soils

Transparent soils have evolved in the past two decades as a useful tool for the physical modeling of soil-structure interaction mechanisms, saturated-unsaturated hydraulic behavior, and thermal processes in soils. This paper traces the history of the development of transparent soil surrogates used in laboratory 1-g bench-scale and centrifuge tests to investigate a variety of geotechnical applications. Many notable papers that appear in this special issue of the journal on modeling with transparent soils are introduced throughout the review. The paper also looks into the future to anticipate where further advances and applications of these materials and complementary technologies may be expected.

Innovations in E-learning, Instruction Technology, Assessment and Engineering Education

Innovations in E-learning, Instruction Technology, Assessment and Engineering Education includes a set of rigorously reviewed world-class manuscripts addressing and detailing state-of-the-art research projects in the areas of Engineering Education, Instructional Technology, Assessment, and E-learning. Innovations in E-learning, Instruction Technology, Assessment and Engineering Education includes selected papers form the conference proceedings of the International Conference on Engineering Education, Instructional Technology, Assessment, and E-learning (EIAE 2006) which was part of the International Joint Conferences on Computer, Information and Systems Sciences and Engineering (CISSE 2006). All aspects of the conference were managed on-line; not only the reviewing, submissions and registration processes; but also the actual conference. Conference participants - authors, presenters and attendees - only needed an internet connection and sound available on their computers in order to be able to contribute and participate in this international ground-breaking conference. The on-line structure of this high-quality event allowed academic professionals and industry participants to contribute work and attend world-class technical presentations based on rigorously refereed submissions, live, without the need for investing significant travel funds or time out of the office. Suffice to say that CISSE received submissions from more than 70 countries, for whose researchers, this opportunity presented a much more affordable, dynamic and well-planned event to attend and submit their work to, versus a classic, on-the-ground conference. The CISSE conference audio room provided superb audio even over low speed internet connections, the ability to display PowerPoint presentations, and cross-platform compatibility (the conferencing software runs on Windows, Mac, and any other operating system that supports Java). In addition, the conferencing system allowed for an unlimited number of participants, which in turn granted CISSE the opportunity to allow all participants to attend all presentations, as opposed to limiting the number of available seats for each session.