Página 16 dos resultados de 2122 itens digitais encontrados em 0.056 segundos

‣ Ecohydrology of a seasonal cloud forest in Dhofar

Hildebrandt, Anke, 1975-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 211 p.; 12165958 bytes; 12193269 bytes; application/pdf; application/pdf
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The hydrology of a semiarid broadleaf forest in Dhofar (Oman) is investigated by performing a field experiment and a modeling study. Based on the results of the field experiment, the ecosystem in Dhofar is classified, for the first time, as a seasonal deciduous cloud forest. Owing to the seasonal cloud cover, the soil storage in this ecosystem is filled and emptied in such a fashion that allows trees to allocate most of the water to transpiration by their relatively deep roots. In addition to annual rainfall amounts of about 100 millimeters, more water is gained by trees directly through interception of cloud droplets (horizontal precipitation). Through- fall measured below the canopy is about twice the rainfall measured above the canopy. Stemflow contributes about one third of the total water received by the soil. Soil moisture observations are consistent with increased infiltration in proximity of the tree trunks. Sap flow and meteorological observations indicate that transpiration is suppressed during the wet season, which allows for deep infiltration of the water received at the surface. This soil water storage supports transpiration by the relatively deep-rooted trees for up to four month into the dry season. All these factors combine to shape and enhance the water conserving nature of the ecosystem...

‣ Using design structure matrices to improve decentralization urban transportation systems; Using DSMs to improve decentralization urban transportation systems

Dunn, Travis P
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 133 p.; 7444773 bytes; 7462072 bytes; application/pdf; application/pdf
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Management of large, complex, urban transportation systems involves numerous stakeholders due to the decentralized ownership and operation of distinct pieces of the physical network. In order to deliver better service to users, many urban regions are adopting technological and operational solutions, both of which necessitate interaction among the decentralized actors. This research applies a systems engineering analysis technique-the design structure matrix (DSM)-in order to improve the efficiency and effectiveness of decentralized organizations involved in urban transportation as they deploy technology and attempt to integrate their operations. DSMs alone provide advantageous, straightforward system representation platforms. Furthermore, clustering algorithms can be applied to DSMs in order to identify potential opportunities to improve the institutional structure of the decentralized system of organizations. We propose DSM representation and clustering as valuable methods for urban regions to identify organizational structures that facilitate both technology deployment through efficient utilization of resources and more effective operations through re-characterizaton of organizational linkages.; by Travis P. Dunn.; Thesis (S.M.)--Massachusetts Institute of Technology...

‣ Resource sharing platform architecture for an information product factory

Sanchez, Abel, 1967-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 235 p.; 16369704 bytes; 16369512 bytes; application/pdf; application/pdf
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Efforts to share resources in collaborative pursuits are hindered by differing data representations, redundant applications, and software incompatibilities. Members of a collaborative effort often span different computational environments and the heterogeneity of contexts disrupts software interoperability. Sharing computational resources has become the focus of many research efforts. Efforts in the 1980s led to the Component Object Model (COM) [Williams, 1998a, 1998b, 1990] and the Common Object Request Broker (CORBA) architectures [Offall et al 1996; OMG, 2003]. In the 1990s both technologies were extended for network support. In recent years, Ian Foster, has phrased the distributed computing problem in terms of sharing computational resources. The grid problem is, "coordinated resource sharing and problem solving in dynamic, multi-institutional virtual organizations", "to support collaborative problem solving in industry, science, and engineering in a data rich environment". [Foster et al, 2001] This work presents a new resource sharing platform architecture for information products that leverages the lessons learned from physical product platforms, the concepts of web services, and grid computing. The platform developed in this thesis integrates the contributions of these three areas into a system that is shown to be more efficient and effective at producing software products.; by Abel Sanchez.; Thesis (Ph. D.)--Massachusetts Institute of Technology...

‣ A dynamic input-output model to project U.S. freight transportation demand; Dynamic I-O model to project United States freight transportation demand

Voigtlaender, Nico, 1977-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 161 p.; 8783266 bytes; 8783075 bytes; application/pdf; application/pdf
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by Nico Voigtlaender.; Thesis (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2002.; Includes bibliographical references (p. 159-161).

‣ Wave-current interaction in water of finite depth

Huang, Zhenhua, 1967-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 269 p.; 9774176 bytes; 9773976 bytes; application/pdf; application/pdf
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In this thesis, the nonlinear interaction of waves and current in water of finite depth is studied. Wind is not included. In the first part, a 2D theory for the wave effect on a turbulent current over rough or smooth bottom is presented. The logarithmic profile of the basic current is modified by the waves due to an effective mean shear stress on the free surface. Surface distortion of the eddy viscosity is shown to be important for the change of the mean velocity profile by waves. Both wave-following and wave-opposing current are studied. Comparisons are made with some existing laboratory experiments. In the second part, an instability theory is presented for the initiation of Langmuir cells due to waves interacting with a turbulent current maintained by tides or by an external pressure gradient. With an infinitesimal span-wise disturbance, the free surface experiences a new mean stress, which generates new vorticity to be diffused downward, and induces further growth. Various contributions to the unstable growth of Langmuir circulation are analyzed by examining the mechanical energy budget. Evidences will be shown that the surface stress contributes significantly to instability. Both wave-following current and wave-opposing current are studied. For the wave-following current...

‣ Economic modeling of intermittency in wind power generation

Cheng, Alan Yung Chen
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 61 p.; 4152971 bytes; 4153221 bytes; application/pdf; application/pdf
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The electricity sector is a major source of carbon dioxide emissions that contribute to global climate change. Over the past decade wind energy has steadily emerged as a potential source for large-scale, low carbon energy. As wind power generation increases around the world, there is increasing interest in the impacts of adding intermittent power to the electricity grid and the potential costs of compensating for the intermittency. The goal of this thesis research is to assess the costs and potential of wind power as a greenhouse gas abatement option for electricity generation. Qualitative and quantitative analysis methods are used to evaluate the challenges involved in integrating intermittent generation into the electricity sector. A computable generation equilibrium model was developed to explicitly account for the impacts of increasing wind penetration on the capacity value given to wind. The model also accounts for the impacts of wind quality and geographic diversity on electricity generation, and the impacts of learning-by-doing on the total cost of production. We notice that the rising costs associated of intermittency will limit the ability of wind to take a large share of the electricity market. As wind penetration increases...

‣ An agent-based approach to HIV/AIDS epidemic modeling : a case study of Papua New Guinea; Agent-based approach to Human T-lymphotropic virus/Acquired immune deficiency syndrome epidemic modeling : a case study of Papua New Guinea

Rhee, Alisa Joy
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 133 p.; 6729976 bytes; 6735521 bytes; application/pdf; application/pdf
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Since AIDS was first discovered, mathematical models of the transmission dynamics of HIV have been developed to determine the drivers of the epidemic. It has become apparent that the most profound factor in the proliferation of this disease is the aggregate effects of individual behavior and perception of risk. Agent-based models (ABM) allow one to simulate the social and sexual interactions which may describe the societal context in which HIV may spread. Using this framework, I construct a simplified social and sexual network that represents Papua New Guinea. This country is used as a case study because it illustrates extremes in network topology. Papua New Guinea is characterized by geographic isolation of ethnic groups, such that ideas of behavior change, stigma reduction, and safe sex practices may spread very slowly. Furthermore, sexual networks in Papua New Guinea are complex and sexual violence and cultural practices may amplify the rate at which HIV is spread. Ultimately, the purpose of HIV transmission models is to hypothesize about drivers of the epidemic which will then shed light on appropriate interventions and prevention measures. ABMs facilitate the development of network-based public health interventions. Such interventions...

‣ Motion control of long span horizontal structures

Shultz, Nicholas A. (Nicholas Andrew)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 85 leaves; 3797075 bytes; 3800567 bytes; application/pdf; application/pdf
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Traditional approaches to structural design presuppose strength to be the dominant design requirement. But following new technologies and design methods, this assumption that strength requirements dominate is being challenged. In the design of horizontal structures, such as floor systems and pedestrian bridges, increasing lengths of column-free span and demands for material efficiency have led to an overall reduction in the structural properties of mass, stiffness and damping. These three properties traditionally controlled motion-related serviceability issues, but this is no longer the case. Engineers are increasingly reporting vibration problems in horizontal structures. Hence, the dominant design criterion has shifted from a basis of strength to one of motion. This thesis attempts to investigate the code requirements and state of the art analysis techniques involved in the vibration control of horizontal structures. Design techniques involving passive control, active control and some alternative control methods are discussed and evaluated, both qualitatively and quantitatively, through a series of example problems.; (cont.) Conventional engineering knowledge addresses vibration problems by increasing stiffness; however, this study indicates that these problems may be resolved much more efficiently by increasing damping...

‣ Resolution of grain scale interactions using the Discrete Element Method

Johnson, Scott M. (Scott Matthew), 1978-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 221 p.
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Granular materials are an integral part of many engineering systems. Currently, a popular tool for numerically investigating granular systems is the Discrete Element Method (DEM). Nearly all implementations of the DEM, however, use spheres to represent particles despite mounting evidence showing that shape at multiple scales (sphericity, angularity, and friction) plays a role in granular material behavior. This thesis contributes a new non-spherical representation to model particles as ellipsoidal bodies. This is validated and benchmarked against current representations and is shown to have attractive computational efficiency and numerical stability. A numerical study of the formation of heaps using spheres and ellipsoids both validates the ellipsoid representation and illustrates shape-induced behavioral differences. Resolution of shape is extended by a new algorithm for a hierarchical, multi-scale representation of convex particle surface characteristics. Two applications are offered: (1) a micro-asperity model is used to demonstrate pair-wise interlocking, and (2) a surface-based cohesive contact law is validated using a series of virtual numerical pull-off tests, which agree well with experimental findings. An explicit quadrature algorithm based on quaternion rotation is developed and shown to more accurately determine rotational orientation with less computational effort than other common algorithms for integrating finite rotations.; (cont.) Finally...

‣ Blooms of the toxic dinoflagellate Alexandrium fundyense in the Gulf of Maine : investigations using physical-biological model

Stock, Charles A. (Charles Andrew), 1975-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 269 p.
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Blooms of the toxic dinoflagellate Alexandrium fundyense are annually recurrent in the western Gulf of Maine (WGOM) and pose a serious economic and public health threat. Transitions between and vital rates within the life stages of A. fundyense are influenced by diverse environmental factors, and these biological dynamics combine with energetic physical motions to yield complex bloom patterns. In this thesis, a biological model of the A. fundyense life cycle developed from laboratory and field data is combined with a circulation model to test hypotheses concerning the factors governing A. fundyense blooms in the springs of 1993 and 1994. There is considerable uncertainty with the biological dynamics, and several biological model structures are tested against the 1993 observations. Maximum likelihood theory is used to evaluate the statistical significance of changes in model/data fit between structures. Biological formulations that do not include either nitrogen limitation or mortality overestimate observed cell abundances and are rejected. However, formulations using a wide range of mortality and nitrogen dependence, including the exclusion of one or the other, were able to match observed bloom timing and magnitude and could not be statistically differentiated. These simulations suggest that cysts germinating offshore of Casco Bay provide a plausible source of cells for the blooms...

‣ A constitutive model for the compression behavior of Old Alluvium

Nikolinakou, Maria-Aikaterini, 1976-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 266 p.
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Old Alluvium is classified as a transported, in-situ weathered tropical soil, and represents a class of geomaterials that have a complex microstructure, including cemented aggregates at the meso-scale and groups of clay stacks at the micro-scale. Despite the presence of significant fractions of nontronite (smectite species), the activity of charged clay particles is initially masked by the aggregation of iron oxides. Compression loading breaks the cementation at the meso-scale and causes physico-chemical changes at the micro-scale, which reveal the expansive characteristics of the clay minerals. It is difficult to achieve a fully disaggregated condition (through mechanical mixing or selective chemical dissolution) and hence, there is little practical value in referencing properties of the intact soil to a hypothetical disaggregated or intrinsic state as proposed for other bonded soils. The proposed formulation describes the variation of compressibility according to a measure of the microstructural changes using the Cation Exchange Capacity as a state variable. Upon load reversal, a model based on double layer theory is integrated to predict macroscopic volumetric expansion due to the swelling of the nontronitic clay fraction. This behavior is also linked to the Cation Exchange Capacity through the preconsolidation stress level...

‣ Nanomechanical properties of hydrated organic thin films

Choi, Jae Hyeok
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 171 leaves
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Hydrated organic thin films are biological or synthetic molecularly thin coatings which impart a particular functionality to an underlying substrate and which have discrete water molecules associated with them. Such films exist in biology (e.g. cell membrane lipid bilayers) and have a broad array of potential engineering applications (e.g. biological implant and sensor surfaces, marine antifouling paints etc.). This doctoral thesis focuses on two important classes of hydrated organic thin films that were prepared and studied in vitro. The first model system was an oligo(ethylene oxide)-based self-assembling monolayer (OEO-SAM) which is a synthetic material that is known to exhibit exceptional resistance to nonspecific protein adsorption and, hence, it is a viable candidate for producing implant surfaces with improved biocompatibility. The second model system was the biologically relevant phosphorylcholine(PC)-supported lipid layer which mimics the structure of the cell membrane. The objective of this doctoral thesis was to quantify the functional form of the net surface interaction (force versus separation distance, F(D)), as well as the contact mechanical properties (e.g. elasticity, plasticity, fracture) of these two model systems under different solution conditions...

‣ Better learning of mechanics through information technology

Regalado S., Carlos A. (Carlos Andrés Regalado Santamaría), 1971-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 254 p.; 9507153 bytes; 9540898 bytes; application/pdf; application/pdf
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(cont.) visualize complex geometric arrangements. Finally, the tools developed represent an alternative to what learning technology has always done; transmit academic knowledge to the student. These tools are an example of how IT can be used to go beyond the traditional forms of academic teaching by using technology with an approach that is not attached to this transmission model. They also show how to exploit the adaptive potential of IT to serve a different, more effective kind of learning.; The use of Information Technology (IT) in engineering education offers the opportunity to teach concepts more effectively than the methods of instruction most commonly used. IT can assist students in making abstractions and improve their understanding of more complicated concepts starting from simple principles and/or real-world physical phenomena. This thesis presents two interactive computer-aided learning tools. For their development, educational theory is first reviewed from which important learning concepts are extracted. These concepts are proposed as essential elements to be incorporated in computer-assisted learning tools. The thesis also reviews the history of technology in education since the 1600's, including the major contributions...

‣ The global walkability index

Krambeck, Holly Virginia
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 135 p.; 8703722 bytes; 8703472 bytes; application/pdf; application/pdf
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Although a significant number of trips are made by foot in developing cities, pedestrian infrastructure, amenities, and services are often neglected in municipal planning and budgets. Since helping city planners understand the scope and extent of local pedestrian conditions relative to other cities would be a positive step towards improving the quality of the pedestrian environment, I was retained by the World Bank to devise a walkability index, which would rank cities across the world based on the safety, security, and convenience of their pedestrian environments. To accomplish this task, I first generated a list of Index variables by studying existing tools for evaluating non-motorized transport and by consulting experts from a variety of related fields. After considering different methods for survey area selection, field data collection, and data aggregation, I created prototypes of the index and survey materials and organized field tests in cities throughout the world, including Beijing, Washington, and Delhi. I also oversaw a full-scale pilot in Ahmedabad, India, where 65 volunteers from the Centre for Environmental Planning and Technology (CEPT) conducted physical infrastructure, public agency, and pedestrian surveys in eight neighborhoods...

‣ Quantifying the cost uncertainty of climate stabilization policies

Franck, Travis Read
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 63 p.; 3176340 bytes; 3176689 bytes; application/pdf; application/pdf
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Climate change researchers are often asked to evaluate potential economic effects of climate stabilization policies. Policy costs are particularly important because policymakers use a cost/benefit framework to analyze policy options. Many different models have been developed to estimate economic costs and to inform cost/benefit decisions. This thesis examines what impact modelers' assumptions have on a model's results. Specifically, MIT's Emissions Prediction and Policy Analysis (EPPA) model is examined to understand how uncertainty in input parameters affect economic predictions of long-term climate stabilization policies. Eleven different categories of parameters were varied in a Monte Carlo simulation to understand their effect on two different climate stabilization policies. The Monte Carlo simulation results show that the structure of stabilization policy regulations has regional economic welfare effects. Carbon permits allocated by a tax-based emissions path favored energy importers with developed economies (e.g., the US and the EU). Countries with energy-intensive economies (e.g., China) will likely have negative welfare changes because of strict carbon policy constraints. Oil exporters (e.g., the Middle East) will also be negatively impacted because of terms of trade fluxes. These insights have implications for stabilization policy design. The uncertainty surrounding economic projections expose some countries to larger economic risks. Policies could be designed to share risks by implementing different permit allocation methods. Direct payments are another means to compensate countries disproportionately disadvantaged by a stabilization policy.; by Travis Read Franck.; Thesis (S.M.)--Massachusetts Institute of Technology...

‣ Outsourcing transportation infrastructure maintenance : a theoretical approach with application to JR East

Hirano, Jun, 1974-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 98 p.; 4080165 bytes; 4079973 bytes; application/pdf; application/pdf
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In transportation agencies, how to reduce maintenance and operation cost is one of the biggest and most common concerns, because their revenue is not expected to increase drastically in the future. One of the solutions undertaken nowadays is contracting out and utilizing contractors' efficiency for cost cutting and performance improvements. Actually, highway agencies in the US have already tried several pilot programs, employing performance-based contract, aiming at reducing their cost of maintenance and rehabilitation of their assets. It has been reported that these agencies achieved huge cost-reduction and performance improvement at the same time by implementing these strategies. Railway infrastructure maintenance is not outsourced as much as highway maintenance in the US. However, a theoretical discussion about outsourcing and contracting shows that railway track maintenance can be outsourced to enhance operating efficiency. Exploring the cases in several railway organizations and highway agencies, fixed-price contract with incentive schemes turn out to be mainly utilized. Evaluating maintenance contractor's performance by several comprehensive performance metrics is also a useful tool to manage and control the contractor's performance...

‣ Real options approach to capacity planning under uncertainty

Mittal, Geetanjali, 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 138 p.; 8642943 bytes; 8660860 bytes; application/pdf; application/pdf
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This thesis highlights the effectiveness of Real Options Analysis (ROA) in capacity planning decisions for engineering projects subject to uncertainty. This is in contrast to the irreversible decision-making proposed by the deterministic strategies based on expected estimates of parameters drawn years in advance. Effectiveness is measured by three metrics: cost efficiency, capacity sufficiency and Value at Risk. The study documents the effects of uncertainty on planning facilities with high fixed-costs. It addresses engineers and planners by presenting fundamental insights of ROA without expecting Options-pricing knowledge a priori. The main idea is demonstrated via a case study of hydropower capacity planning. An analytical probabilistic capacity planning tool is developed to compare results given by traditional valuation and ROA. The tool may be useful for determining resource utilization policies and decision-making in the construction of such plants. Two specific options have been examined: (1) Vary size and timing of capacity increment (2) Defer hydropower plant construction to observe demand by relying on low fixed-cost and high operational-cost facilities in the initial years. The conclusion is that dynamic capacity planning approach is more effective if the forecasts are pessimistic or optimistic but not necessarily if realized parameters are similar to forecasts. Decisions based on distribution of driving factors and outcomes may be better aligned with the management's overall risk preferences than those based solely on expected mean of these parameters.; by Geetanjali Mittal.; Thesis (S.M.)--Massachusetts Institute of Technology...

‣ A performance based approach for seismic design with hysteretic dampers

Keten, Sinan
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 99 leaves; 3585053 bytes; 3589151 bytes; application/pdf; application/pdf
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Current trends in structural engineering call for strict performance requirements from buildings prone to extreme earthquakes. Energy dissipation devices are known to be effective in reducing a building's response to earthquake induced vibrations. A promising strategy for controlling damage due to strong ground motion is the use of buckling restrained braces that dissipate energy by hysteretic behavior. Research conducted in the past reveals that devices such as The Unbonded Brace (TM) provide stiffness and damping to the structure, two key parameters that characterize a building's performance. The focus of this thesis is the development of a preliminary motion-based design methodology for the use of these devices in mitigating damage to structural and non-structural elements. In this regard, a shear beam idealization for a typical 1 0-story steel building is adopted and nonlinear dynamic response of the building for a set of earthquakes is simulated. Optimal ductility ratio and stiffness contribution of the bracing system is determined based on the inter-story drift values obtained from simulation results.; by Sinan Keten.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2006.; Includes bibliographical references (leaves 66-67).

‣ An application service provider infrastructure for shared workspaces in Internet-based collaborative design

Solari, Jaime, 1973-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 107 leaves; 8627111 bytes; 8626866 bytes; application/pdf; application/pdf
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For architectural, engineering and construction projects involving transient 'virtual organizations' composed of non-collocated team-members, the adoption of concurrent design principles is seen as vital. An important aspect of concurrent design is the need for an effective communications infrastructure between team members. Traditionally, such communication has been handled through person-to-person meetings, however the complexity of modern projects has grown and as a result, reliance on new information and communications technologies is becoming increasingly necessary. Hence, within a concurrent design setting, there is the need for an integrated information and collaboration environment that will create a persistent shared workspace to support interaction between project personnel throughout all phases of the project. This research explores computer-supported mechanisms for enhancing distributed design collaboration. The goal of this thesis is to develop a set of requirements, system architecture and an early system prototype to facilitate computer-supported collaboration among distributed teams. The prototype will consist of a persistent shared workspace system built from the integration of complementary collaborative applications. These applications are the CAIRO system...

‣ Discrete particle transport in porous media : discrete observations of physical mechanisms influencing particle behavior

Yoon, Joon Sik, 1973-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 362 p.
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An understanding of how discrete particles in the micron to submicron range behave in porous media is important to a number of environmental problems. Discrete particle behavior in the interior of a porous medium is complex and influenced by various physical and chemical factors. This work aimed to provide new insight into the physical factors influencing discrete particle movement and attachment in a uniform, saturated porous medium. As part of this aim, a new technique for visualizing discrete particle transport in the interior of a porous medium has been developed. The technique, which includes the construction of a translucent medium and the use of laser induced fluorescence for particle tracking, was used to examine the behavior of a 50 mg/L suspension of negatively charged, micron-size, non-Brownian particles in the interior of a porous medium constructed from water saturated, mono-size 4mm diameter glass beads. Particle behavior as a function of pore fluid velocity and solid surface roughness was imaged at both the macroscopic and microscopic level. Experimental results revealed two interactions between the discrete particles and the solid phase of the medium. One, particle entrapment, resulted in the firm collection of particles at solid-solid contact points and asperities on the solid surfaces. The other...