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Articles 1 - 12 of 12
Full-Text Articles in Engineering
Heavy Metal Adsorption On Iron Oxide And Iron Oxide-Coated Silica : Macroscopic, Spectroscopic, And Modeling Studies, Ying Xu
Dissertations
To accurately model metal mobility and bioavailability in soils and sediments, systematic sorption studies are needed using representative and well-characterized minerals. Two important surfaces are iron oxide and silica, which are ubiquitous and associated with one another in the environment playing important roles in metal distribution. The objectives of this research are to develop models for predicting speciation and mobility of toxic trace metal ions in groundwater, soils, and sediments when competing ions are present. A model system for soils and sediments, iron oxide-coated silica, was synthesized; the degree of coatings was highly sensitive to the particle size of silica …
Dynamic Model Of Hiv/Aids Population Of Agra Region, D. K. Chaturvedi
Dynamic Model Of Hiv/Aids Population Of Agra Region, D. K. Chaturvedi
D. K. Chaturvedi Dr.
The Human Immunodeficiency Virus / Acquired Immunodeficiency syndrome (HIV/AIDS) is spreading rapidly in all regions of the world. But in India it is only 20 years old. Within this short period it has emerged as one of the most serious public health problems in the country, which greatly affect the socio-economical growth. The HIV problem is very complex and ill defined from the modeling point of view. Keeping in the view the complexities of the HIV infection and its transmission, it is difficult to make exact estimates of HIV prevalence. It is more so in the Indian context, with its …
A Dynamic Model Of The Human/Cooling System/Clothing/Environment System, Zhengxiang Pu
A Dynamic Model Of The Human/Cooling System/Clothing/Environment System, Zhengxiang Pu
Electronic Theses and Dissertations
The human body compensates well for moderate climatic heat stress, but artificial environments often block or overwhelm physiological defense mechanism. Personal protective equipment (PPE) is one of sources of heat stress. It protects individual from chemical, physical, or biological hazards, but the high thermal insulation and low vapor permeability of PPE may also lead to substantial heat stress. Personal cooling is widely used to alleviate heat stress, especially for those situations where ambient environmental cooling is not economically viable or feasible. It is important to predict the physiological responses of a person wearing PPE with personal cooling to make sure …
Benchmark Studies For Structural Health Monitoring Using Analytical And Experimental Models, Jason Lee Burkett
Benchmark Studies For Structural Health Monitoring Using Analytical And Experimental Models, Jason Lee Burkett
Electronic Theses and Dissertations
The latest bridge inventory report for the United States indicates that 25% of the highway bridges are structurally deficient or functionally obsolete. With such a large number of bridges in this condition, safety and serviceability concerns become increasingly relevant along with the associated increase in user costs and delays. Biennial inspections have proven subjective and need to be coupled with standardized non-destructive testing methods to accurately assess a bridge's condition for decision making purposes. Structural health monitoring is typically used to track and evaluate performance, symptoms of operational incidents, anomalies due to deterioration and damage during regular operation as well …
Developing And Using Landslide Size Frequency Models, A. T. Moon, R. A. Wilson, P. Flentje
Developing And Using Landslide Size Frequency Models, A. T. Moon, R. A. Wilson, P. Flentje
Faculty of Engineering - Papers (Archive)
Predicting the size and frequency of landslides is essential in landslide risk assessment. Records of past landslides are invariably incomplete and often provide little guidance on infrequent events. Presenting size frequency models graphically has the advantage of showing how observations, interpretations and judgements are interrelated, allows patterns to be recognized and understood, and models for different situations to be easily compared. Slope retreat rates were used to calibrate landslide size frequency models for individual slope units on an oversteepened escarpment above a road threatened by landslides in Australia. Evidence based models should be developed early and should be based on …
A Deformable Model With Cellular Neural Network, Yongmin Zhong, Bijan Shirinzadeh, Gursel Alici, Julian Smith
A Deformable Model With Cellular Neural Network, Yongmin Zhong, Bijan Shirinzadeh, Gursel Alici, Julian Smith
Faculty of Engineering - Papers (Archive)
This paper presents a new methodology for deformable models by drawing an analogy between cellular neural network (CNN) and elastic deformation. The potential energy stored in an elastic body as a result of a deformation caused by an external force is propagated among mass points by the local connectivity of cells and the CNN dynamics. An improved CNN model is developed for propagating the energy generated by the external force on the object surface. A method is presented to derive the internal forces from the potential energy distribution established by the CNN. The methodology proposed in this paper can not …
A Quasi-Dynamic Nonlinear Finite Element Model To Investigate Prosthetic Interface Stresses During Walking For Trans-Tibial Amputees, Xiaohong Jia, Ming Zhang, Xiaobing Li, Winson Lee
A Quasi-Dynamic Nonlinear Finite Element Model To Investigate Prosthetic Interface Stresses During Walking For Trans-Tibial Amputees, Xiaohong Jia, Ming Zhang, Xiaobing Li, Winson Lee
Faculty of Engineering and Information Sciences - Papers: Part A
Background. To predict the interface pressure between residual limb and prosthetic socket for trans-tibial amputees during walking. Methods. A quasi-dynamic finite element model was built based on the actual geometry of residual limb, internal bones and socket liner. To simulate the friction/slip boundary conditions between the skin and liner, automated surface-to-surface contact was used. Besides variable external loads and material inertia, the coupling between the large rigid displacement of knee joint and small elastic deformation of residual limb and prosthetic components were also considered. Results. Interface pressure distribution was found to have the same profile during walking. The high pressures …
Model-Based Adaptive Control Of Piezoelectric Actuation Systems, Hwee Choo Liaw, Denny Oetomo, Bijan Shirinzadeh, Gursel Alici
Model-Based Adaptive Control Of Piezoelectric Actuation Systems, Hwee Choo Liaw, Denny Oetomo, Bijan Shirinzadeh, Gursel Alici
Faculty of Engineering - Papers (Archive)
This paper proposes a model-based adaptive control methodology for piezoelectric actuation systems to follow specified motion trajectories. This is motivated by a search for an effective control strategy to deal with the problem of parametric uncertainties such as disturbance and hysteresis effects. The proposed adaptive law is formulated by combining a parameter compensator and a conventional PD feedback control for a system to drive its position tracking error converging to zero. The fundamental concept lies in the properties of a quasinatural potential function, which allows a saturated position error function in the control formulation. Implementation of the control law requires …
Navigation Aids In Route Training: Increase Navigation Speed, Decrease Route Retention?, John Holmquist
Navigation Aids In Route Training: Increase Navigation Speed, Decrease Route Retention?, John Holmquist
Electronic Theses and Dissertations
In the case of one car following another to a destination, it is very effective at getting the second vehicle to the destination quickly; however, the driver of the second car may not learn the route. Yet, for individuals, such as firefighters, law enforcement, and military personnel, it is imperative that a route be learned quickly and accurately and that an awareness of the situation is maintained while they traverse the given route. This leads to three questions, (a) will navigation aids affect initial route navigation; (b) will navigation aids affect retention; and (c) will navigation aids affect situation awareness …
Adapting The Modified Cam Clay Constitutive Model To The Computational Analysis Of Dense Granular Soils, Jose Arvelo
Adapting The Modified Cam Clay Constitutive Model To The Computational Analysis Of Dense Granular Soils, Jose Arvelo
Electronic Theses and Dissertations
The computational constitutive Modified Cam Clay Model (MCCM) was developed at Cambridge to study the behavior of clays and has been proven to be effective. In this study, this model is extended to the case of dense sands to analyze the accuracy of the stress-strain behavior. This analysis is based on triaxial test data applied to remolded and compacted sand samples under drained conditions. The laboratory triaxial tests were performed by the Florida Department of Transportation to research the permeability effect in sandy soils compacted up to 95% of maximum unit weight at the optimum moisture content. Each soil sample …
Thermo And Kinetic Studies On The Sorption And Desorption Of Hydrophobic Organic Contaminants In Sediments, Yunzhou Chai
Thermo And Kinetic Studies On The Sorption And Desorption Of Hydrophobic Organic Contaminants In Sediments, Yunzhou Chai
LSU Doctoral Dissertations
This study investigated the correlation of desorption resistance of hydrophobic organic contaminants (HOCs) in sediment and the heterogeneity of sediment organic matter (SOM). The amorphous and condensed phase organic carbon contents were defined by the method of Gustafsson et al. (1997) using thermal oxidation of sediment under 375°C. The desorption-resistant fraction of contaminants in sediments was operationally defined as the fraction that could not be removed by the adsorbent XAD-2. The correlation of the desorption-resistant fraction with sediment organic carbon characteristics was evaluated for both laboratory-inoculated and field-contaminated sediments. No strong correlation between the desorption resistant fraction in laboratory-inoculated sediments …
Mathematical Models For Estimating Volatile Chemical Emissions From Dredging Operations, Kenneth Alexander Fountain
Mathematical Models For Estimating Volatile Chemical Emissions From Dredging Operations, Kenneth Alexander Fountain
LSU Master's Theses
Dredging operations have been a common remediation for contaminated sediment in an effort to reduce the harmful impact on the environment. The objective of this research was to create models used for estimating chemical release to air from remediating the Indiana Harbor and Canal (IHC) as three separate dredging operations; the Dredge Site, Exposed DM CDF, and Ponded CDF. The evaporative flux estimations are based on a two-resistance mass transport path inclusive of both the molecular diffusion in porous media and interfacial airside mass transport resistances. Several chemodynamic algorithms were used in calculating key transport parameters. Laboratory tests were performed …