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Mass Transfer Mechanisms In Air Sparging Systems , Washington Jose Braida Jan 1997

Mass Transfer Mechanisms In Air Sparging Systems , Washington Jose Braida

Retrospective Theses and Dissertations

The air-water mass transfer of VOCs during air sparging was investigated using a single-air channel air sparging setup and a 14 cm (51[over] 2 in) diameter soil column. Three different porous media and 10 VOCs were used in the study. Air velocities ranged from 0.2 cm/s to 2.5 cm/s. Experimental results for the single-air channel setup indicated that volatilization of VOCs during air sparging was a diffusion limited process. VOCs, in a thin layer of saturated porous media next to the air channels (identified as the mass transfer zone, MTZ), were found to deplete rapidly ...


Shear Strength Of Shredded Tires As Applied To The Design And Construction Of A Shredded Tire Stream Crossing, Megan Alissa Gebhardt Jan 1997

Shear Strength Of Shredded Tires As Applied To The Design And Construction Of A Shredded Tire Stream Crossing, Megan Alissa Gebhardt

Retrospective Theses and Dissertations

Scrap tire stockpiles have grown in the United States leading to a significant disposal problem. The most recent survey conducted by the Scrap Tire Management Council reported that 850 million tires are stockpiled in the United States, with an additional 250 million tires still generated each year (1995). The research described herein was undertaken to develop design guidelines for shredded tire stream crossings. The shear strength properties have been investigated for tire shreds as well as tire shreds in contact with glacial till. The shredded tires range from 40 mm to 1.4 m in length. There are several documented ...


Autocorrelation Techniques For Soft Photogrammetry , Wu Yao Jan 1997

Autocorrelation Techniques For Soft Photogrammetry , Wu Yao

Retrospective Theses and Dissertations

In this thesis research is carried out on image processing, image matching searching strategies, feature type and image matching, and optimal window size in image matching. To make comparisons, the soft photogrammetry package SoftPlotter is used. Two aerial photographs from the Iowa State University campus high flight 94 are scanned into digital format. In order to create a stereo model from them, interior orientation, single photograph rectification and stereo rectification are done;Two new image matching methods, multi-method image matching (MMIM) and unsquare window image matching are developed and compared. MMIM is used to determine the optimal window size in ...


Laboratory Studies On The Temperature-Phased Anaerobic Digestion Of Mixtures Of Primary And Waste Activated Sludge , Yue Han Jan 1997

Laboratory Studies On The Temperature-Phased Anaerobic Digestion Of Mixtures Of Primary And Waste Activated Sludge , Yue Han

Retrospective Theses and Dissertations

The temperature-phased anaerobic digestion (TPAD) involves the operation of two reactors in series, the first maintained at a thermophilic temperature (commonly 55° C) and the second maintained at a mesophilic temperature (commonly 35° C).;The purpose of the research was to compare the performance of the temperature-phased system with the conventional single-stage mesophilic system for treating mixtures of primary sludge (PS) and waste activated sludge (WAS). The TPAD systems used in the study consisted of two, completely-mixed reactors operated in series. The first and the second stages were operated at 55° C and 35° C, respectively. The single-stage system was ...


Compressibility, Hydraulic Conductivity, And Soil Infiltration Testing Of Tire Shreds And Field Testing Of A Shredded Tire Horizontal Drain, Peter Shane Zimmerman Jan 1997

Compressibility, Hydraulic Conductivity, And Soil Infiltration Testing Of Tire Shreds And Field Testing Of A Shredded Tire Horizontal Drain, Peter Shane Zimmerman

Retrospective Theses and Dissertations

Laboratory testing to determine the engineering characteristics of 0.2 m to 0.4 m tire shreds was undertaken. A large scale permeameter, which allowed vertical compression of the shreds, was designed. The compressibility of the tire shreds was found. The hydraulic conductivity of the tire shreds was found at various vertical strains and flow rates. Hydraulic conductivity ranged from 1 cm/s to 8 cm/s. Hydraulic conductivity was highest at low flow rates and zero vertical strain. The hydraulic conductivity results were compared to the results of other researchers. A soil infiltration experiment was conducted to establish whether ...


Development Of Computer Software For Simulation Of Transmission Line Dynamic Behavior , Amr Mohamed Abd Elaziz Nafie Jan 1997

Development Of Computer Software For Simulation Of Transmission Line Dynamic Behavior , Amr Mohamed Abd Elaziz Nafie

Retrospective Theses and Dissertations

Structural failure of transmission line systems is often attributed to dynamic effects such as a broken conductor, a broken insulator, or conductor galloping. The focus of this research was to develop a computer program, DYNTRN, that can analyze the structural response of a transmission line system due to dynamic effects, and present the response in a graphical form. The program uses the stiffness method to analyze a system consisting of conductors, insulators, and support structures. Four types of elements can be used to model the transmission line components: beam elements, cable elements, truss elements, and spring elements. A dynamic condensation ...


The Temperature Phased Anaerobic Biofilter-Asbr Process , Christopher Gerald Schmit Jan 1997

The Temperature Phased Anaerobic Biofilter-Asbr Process , Christopher Gerald Schmit

Retrospective Theses and Dissertations

The temperature phased anaerobic biofilter-ASBR system is a new system that has been developed at Iowa State University. The temperature phased system employs a first stage thermophilic (55°C) biofilter reactor followed in series by a second stage mesophilic (35°C) anaerobic sequencing batch reactor (ASBR). The idea of temperature phased anaerobic treatment is to eliminate the disadvantages of both thermophilic (poor organic removals) and mesophilic (long retention times) temperatures while retaining the advantages of both these temperatures (fast reaction rates at thermophilic temperatures and good organic removal efficiencies at mesophilic temperatures);Three temperature phased systems were operated in the ...


Computer Aided Parametric-Planning (Capp), Faramarz Rahbar Jan 1997

Computer Aided Parametric-Planning (Capp), Faramarz Rahbar

Retrospective Theses and Dissertations

Today's challenge of fast technological advances and global competition requires a shift in our planning paradigm. The "same old way" simply does not bring about the necessary results. Our paradigm must change to reflect this. Continuous improvement of the planning process is essential to achieve success. Research indicates that the key to project success is to invest quality time in systematic planning at an early stage. Yet, we have relied upon mostly unstructured and manual formation of plans. Existing scientific planning techniques (i.e. Critical Path Method) are scheduling tools for analysis rather than plan generation. They manipulate data ...


Computerized Flood Prediction Modeling Of The Squaw Creek Basin Using The Hec1 Model, Karla Kay Heeren Tebben Jan 1997

Computerized Flood Prediction Modeling Of The Squaw Creek Basin Using The Hec1 Model, Karla Kay Heeren Tebben

Retrospective Theses and Dissertations

No abstract provided.