Geological and Geotechnical Engineering in the New Millennium Opportunities for Research and Technological Innovation (2006) / Chapter Skim
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3 Meeting the Challenges With New Technologies and Tools
3 Meeting the Challenges With New Technologies and Tools
Pages 83-126
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Emphasis is placed on the emerging technologies that are focal areas for research expenditures nationwide, including bioengineering, nanotechnology, sensors and sensing, geophysical methods, remote sensing, and informa tion technology and cyber infrastructure. National Science Foundation (NSF)
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provide an entrée to the field for geoengineering researchers. The second part is intended to spark the imagination about the possible application of these technologies.
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From page 85... ...
Meeting the Challenges With New Technologies and Tools surface fundamentally from a highly reducing environment to an oxidized environment. The evolution of photosynthetic organisms beginning approximately 3.5 billion years ago established present-day oxygen concentrations and radically changed physical, geological, chemical, and biological processes on our planet (see Figure 3.1)
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Addi tional information on biological principles and biomediated geochemical processes, their role on the evolution of Earth, and their potential applications is in Chapelle (2001) , Ehrlich (1996, 1999)
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aware of them and are beginning to study their role in determining and controlling soil properties and behavior and exploiting them in engineering applications. Geoenvironmental engineering applications.
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Geomechanical applications. Biomediated geomechanical processes can have significant impacts on the geomechanical behavior of Earth materials.
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Such techniques could result in faster excavation methods, and a reduction or elimination of excavation support and water control. These are only a few examples of the potential applications offered by a new paradigm of biomediated geochemical processes in geoengineering.
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A central challenge in geo engineering is to understand the changes in properties and behavior in moving from large to small, whereas a central theme in nanotechnology is to take advantage of this transition and attain novel material perfor mance through nanostructuring of new materials. Material properties may be affected or engineered using nanoscale building blocks, control ling their size, size distribution, composition, shape, surface chemistry, and manipulating their assembly.
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Atomic force microscopes can reach a sensitivity of sub-attonewton (1018N) and deploy multiple parallel sensing probes for faster data gathering.
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Among the application areas receiving attention at the present are nanoelectronics, optoelectronics, and magnetics; microspacecraft; bionanodevices for detection and mitigation of health threats; healthcare, therapeutics and diagnostics healthcare; and energy conversion and storage. Additional information on fundamental aspects of nanotechnology and its applications is given in Zhang et al.
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Meeting the Challenges With New Technologies and Tools TABLE 3.2 Analysis and Engineering at Macro- and Nanoscales MACROSCALE ENGINEERING NANOSCALE ENGINEERING IS DONE CONSIDERING THAT IS DONE CONSIDERING THAT General · Continuum behavior · Analysis of discrete particle behavior properties · Generalized constitutive models · In terms of discrete atomic nature of are applicable matter · The discrete distribution of charges · Quantized energy · The failure of continuum theories at this scale Magnetic · Magnetic responses reflect the · Magnetic response reflects the electron's properties average of individual magnetic intrinsic spin fields of a system's constituents · Quantum tunneling of magnetic moment is observed (nanomagnets) Conduction · Flow is continuous according to · Mean free path of phonons becomes and Darcy's law, Ohm's law, comparable to the prevailing scale transport Fourier's law, Fick's law, · Transport is sporadic and irregular processes Advection-dispersion equation · Charge confinement and surface effects produce electronic density states (nanodots)
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GEOLOGICAL AND GEOTECHNICAL ENGINEERING IN THE NEW MILLENNIUM 3.2.2 Nanotechnology and Geoengineering A comparison of scales in nanotechnology and geomaterials was noted above and is presented graphically in Figure 3.3. As this figure shows, the fundamental behavior of clays is a nanomechanics problem, suggesting that concepts and models developed in nanotechnology can provide new insights and enhanced understanding of the behavior of clay-size particles and, even more important, new means to manipulate or modify this behavior.
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deflocculated-dispersed flocculated - aggregated Edge IEP Face or Particle IEP pH < 4 No global repulsion van der Waals attraction ?
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3.3 SENSORS AND SENSING SYSTEM TECHNOLOGIES 3.3.1 Background Microelectromechanical systems (MEMS) integrate mechanical elements, sensors, actuators, and electronics on a common silicon sub strate using microfabrication technology, as described in Sidebar 3.2.
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Wireless communication offers important advantages in the development of sensing systems. A generic wireless sensor platform includes an antenna, a power supply, a transceiver, signal processing circuitry, and a microprocessor to run the sensing and networking software.
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integrate mechanical elements, sensors, actuators, and electronics on a common silicon substrate through microfabrication technology. While the electronics are fabricated using integrated circuit process sequences (e.g., CMOS, Bipolar, or BICMOS processes)
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a detail of the packaged die. This gyroscope has many common mechanical elements, and measures rate of twist around the normal to the plane of the device.
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involve sensor design for such purposes as biomimetic (life mimicking) applications, toxic agent detection, chip-based sensing systems, remote activation and interroga tion, and self-calibration; sensor arrays and networks for multisensor monitoring, information transfer, ultralow power nodes, data manage ment, distributed network control, and smart devices that self-assemble into networks; and information interpretation and use for decision and feedback, sampling, location optimization, monitoring, and diagnostic tools.
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Consequently, it is important to consider the use and adaptation of commercial off-the-shelf devices for geoengineering applications whenever possible. The continuing revolution in sensing technology enhances our ability to see into Earth (NRC, 2000)
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. We can imagine geoengineering applications such as real-time monitoring of geostructures during occurrence of natural hazards (e.g., hurricanes, floods, and earthquakes)
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3.3.3 Human Factors While this section of the report has focused on the potential contributions to geoengineering from new sensing tools, the importance of human factors in applying these tools and technologies cannot be overlooked. For instance, successful application of any monitoring program, whether using old established technology or new innovative sensors and networked instrumentation systems, depends on a variety of seemingly mundane tasks, including procurement, calibration, and acceptance of hardware and software, installation and baseline monitoring of equipment, maintenance and recalibration as needed, data collection and processing, and data interpretation with response actions as warranted.
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An overview of geophysical methods and their underlying principles is presented in Table 3.3. These methods generally provide independent TABLE 3.3 Geophysical Methods PHYSICAL TYPICAL PROPERTY INTERPRETED METHOD PRINCIPLE MEASUREMENT MEASURED PARAMETERS Airborne Detects reflected Aerial Spectral- Geologic lineations, sensing electromagnetic photography and dependent variations in radiation remote sensing in reflectance of vegetation, surface several spectral electromagnetic disturbances bands radiation Electrical Detects current Currents, Electrical Depth, Earth material and flow in subsurface voltages, resistivity resistivity, porosity, electromagnetic materials spatial locations inferred fluid chemistry 104
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Meeting the Challenges With New Technologies and Tools TABLE 3.3 Continued PHYSICAL TYPICAL PROPERTY INTERPRETED METHOD PRINCIPLE MEASUREMENT MEASURED PARAMETERS Ground- Transmits radio Distance, wave Dielectric Shallow interface penetrating waves in the arrival times, permittivity, depth and geometry, radar 10 MHz to and wave electrical electromagnetic 500 MHz band amplitude resistivity, wave speed, into subsurface magnetic electromagnetic wave and detects susceptibility attenuation returning reflected waves Magnetics Detects local Proton Magnetic Geometry and variations in Earth's precession susceptibility magnetic magnetic field frequency susceptibility of local caused by magnetic subsurface features properties of subsurface materials Microgravity Detects localized Displacement of Mass density Depth, geometry, and minute variations a gravitational- density of local in the gravitational force-sensitive subsurface features field of Earth mass Seismic Source of seismic Distance, wave Speeds of Interface depth and methods waves provides arrival time, and compressional, geometry, elastic sampling of elastic wave amplitude, shear, and moduli, location of properties in a different wave surface waves; faults localized volume types attenuation of of Earth these waves Thermal Measures Temperature and Thermal Density, moisture methodsa temperature and temperature conduction, content, thermal changes related to changes at heat capacity anomalies, thermal active or passive specific locations sources, rate of thermal sources geochemical reactions aThermal methods added for this report.
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Recent extensions of medical imaging technology to the field of material science include very-high-resolution MRI and microcomputed tomography with micron-scale resolution. Additional information on geophysical methods, principles, and applications is given in Ward (1990)
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Therefore, medical imaging is much more accurate than geoengineering imaging. In addition, complexities in processing geophysical data associated with underlying physical concepts, mathematical modeling and inversion, and final interpretation have further deterred the direct involvement of the geoengineering community in the development and application of geophysical methods for near-surface applications.
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The effectiveness of noncontacting electromagnetic techniques remains unmatched by seismic methods; however, the limited penetration depth of electromagnetic waves in 108
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have been coupled to state-of-the-art imaging and visualization software to produce very-high-resolution images of the near surface for utility detection in urban environments. Figure 3.5 presents an example of the application of high-resolution geophysical methods for locating subsurface utilities in West Palm Beach.
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Imagine running a centrifuge-modeling experiment and assessing the evolution of the soil mass in the model with nonintrusive tomographic techniques; or monitoring the evolution of soil processes in laboratory cells while simultaneously gathering information with elastic and electromagnetic waves without perturbing the process (consider for example: consolidation, cementation, liquefaction, freezing, remediation, biomediated geochemical stabilization)
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These new techniques must address the need for high resolution compatible with engineering applications, the complementary nature of multiple geophysical methods, and the need for ground truth provided by invasive techniques. 3.5 REMOTE SENSING 3.5.1 Background Remote sensing techniques involve noncontact observation, measurement, and recording from an airborne or space platform of electromagnetic energy reflected by or emitted from a target.
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. 3.5.2 Remote Sensing and Geoengineering The spatial and topographic resolution that can be attained with current remote sensing technology is relevant to many geoengineering applications.
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can determine displacement as small as a few millimeters over hundreds of square miles. Interference images gathered with synthetic aperture radar are shown in Figure 3.6, with applications to ground subsidence and tectonic displacements.
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Landslide hazard maps, flood plain assessments, landslide prediction, monitoring, slope stability in mines and road cuts, and coastal erosion are a few of the geotechnical engineering applications that have used this remote sensing technology. Potential applications of remote sensing in geoengineering are related mainly to large-scale projects and regional activities and planning.
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The growth in computer power has been driven by energy, scientific, and engineering applications, and especially by defense applications such as the Accelerated Strategic Computing Initiative (ASCI) , a project started in 1996 to replace traditional nuclear testing by highly tuned, massive computer simulations (Messina, 1999)
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Spatially varying material properties and geometries representative of actual in situ conditions would result in problems too large and complex for modern computers. The integration of computer technology and communication networks has made distributed information systems possible.
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that the capacity of information technology has crossed thresholds that now make possible a comprehensive cyberinfrastructure on which to build new types of scientific and engineering knowledge environments and organizations and to pursue research in new ways and with increased efficacy. Such environments and organizations enabled by cyberinfrastructure are increasingly required to address national and global priorities 117
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existing monitoring and sensing systems are easily integrated into an information-rich smart system context. There are more than 1,600 catalogued computer programs specifically written to solve geoengineering 118
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. Based on a distributed simulation framework and on advanced computational and FIGURE 3.9 Computer simulations.
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SOURCE: Java based Web interface for earthquake ground motion simulation. Web interface: Tomasz Haupt, Engineering Research Center, Mississippi State University.
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Imagine the application of hybrid systems that will extensively combine dense sensor arrays with computer models to drastically increase the availability of data and decrease uncertainty in geoengineering applications, and allow the rational consideration of all available subsurface data in real-time decision making. While current GIS technology may be employed for developing smart sensor networks for data management, to take full advantage of their database capability current two- and three-dimensional databases must evolve into true geologic data models in which data is stored and interpreted in a geologic context and with multidimensional modeling and interpretation capabilities integrated into the data management, manipulation, and display schemes.
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Application of all these new technologies and the need to incorporate more electronics, biology, chemistry, material science, and information technology into geoengineering has major implications for education as well as practice, and these issues are discussed in Chapter 5. The committee sees tremendous opportunities for advancing geoengineering through interaction with other disciplines, especially in the areas of biotechnology, nanotechnology, MEMS and microsensors, geosensing, information technology, cyberinfrastructure, and multispatial and multitemporal geographical data modeling, analysis, and visualiza tion.
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laboratory measurement through noninvasive sensing · can make geophysical methods cheaper and more pervasive · integration of development work by other industries essential continued 123
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characterization Remote sensing High A new family of · signal processing · ongoing, fruitful area for research unprecedented tools · data management and development will have significant · computer science · ground-truthing observations remain impact in the a research issue short term. · research could address the potential for real-time decision making Information High Its critical role in · data management technology · ongoing developments sensing systems, · computer science · provides a mechanism for geophysics, and collaboration remote sensing will · requires synergy among the computer determine their impact science, engineering, and science in the short term.
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Meeting the Challenges With New Technologies and Tools information technology, or some other technological advancement. Such issues as procurement, calibration, validation, data collection, and data interpretation remain vital to successful implementation of new tools and technologies.
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