The pulp and paper industry has been struggling to meet the new and stringent TRS (Total Reduced Sulphur) emission compliance standards established in recent years. However, a new approach by some regulatory bodies gives intricate operational parameters a new and important role in achieving environmental compliance. TRS compounds that cause the distinctive pulp mill odour, originate from sodium sulphide in white liquor used in the kraft pulping process. Up to 20% of TRS emissions could originate from the lime kiln and lime mud solids content is one of the operational parameters that could help reduce the TRS emissions from the lime kiln. Residual sodium sulphide in the lime mud that results in TRS gases, is dissolved in the moisture content of the mud. Although efficient lime mud washing can remove most of the residual sodium sulphide, the remaining moisture content of the mud still contains some sodium sulphide. Therefore, improved lime mud dewatering can be effective in reducing the TRS emissions from the lime kiln. Data presented in this study confirms that as the lime mud solids content increases, TRS emissions from the lime kiln decrease. Data analysis demonstrates a negative linear correlation at 5% significance level between TRS emissions and lime mud solids.

The pulp and paper industry has been struggling to meet the new and stringent TRS (Total Reduced Sulphur) emission compliance standards established in recent years. However, a new approach by some regulatory bodies gives intricate operational parameters a new and important role in achieving environmental compliance. TRS compounds that cause the distinctive pulp mill odour, originate from sodium sulphide in white liquor used in the kraft pulping process. Up to 20% of TRS emissions could originate from the lime kiln and lime mud solids content is one of the operational parameters that could help reduce the TRS emissions from the lime kiln. Residual sodium sulphide in the lime mud that results in TRS gases, is dissolved in the moisture content of the mud. Although efficient lime mud washing can remove most of the residual sodium sulphide, the remaining moisture content of the mud still contains some sodium sulphide. Therefore, improved lime mud dewatering can be effective in reducing the TRS emissions from the lime kiln. Data presented in this study confirms that as the lime mud solids content increases, TRS emissions from the lime kiln decrease. Data analysis demonstrates a negative linear correlation at 5% significance level between TRS emissions and lime mud solids.

In this report, the application of Principle Component Analysis (PCA) and Partial Least Square (PLS)  regression analyzing methods used to understand the relationship of interdependent loads in municipal wastewater treatment plant. Two different wastewater treatment plants were chosen for analysis of  the relationship between interdependent loads. Firstly, the collected data of incoming wastewater and outgoing water from both Västerås and Eskilstuna wastewater treatment plants were analyzed to find some relationship or correlation between contents and compare the data of both the plants. Secondly, the correlated contents were used to generate the regression model for predicting the value in the future, in this report we have focussed only on ammonium nitrogen value for regression model. The PCA study shows the variation between incoming and outgoing wastewater’s characteristics  given by  Västerås and Eskilstuna plant. / BOD, ammonium nitrogen, nitrogen, phosphorus

This work presents the results of Finite Element Analyses (FEA) used to simulate sliding contact in two (2D) and three dimensions (3D) between two interfering elasto-plastic bodies. Cylinders are used to model sliding contact in 2D, simplified by the assumption of plane strain. Sliding is studied between two cylinders modeled with material properties of steel, and separately with a Glidcop cylinder sliding over an Al 6061-T651 cylinder. All materials are modeled as elastic-perfectly plastic and follow the von Mises yield criterion. Both frictionless as well as frictional sliding are investigated. The FEA results in trends in the deformation, reaction forces, stresses, and net energy loss as a function of sliding distance. All these results are found to be related to the magnitude of vertical interference. This work shows that for the plastic loading cases of frictionless sliding, the ratio of the vertical force to the horizontal reaction force is not zero at the point where the bodies are perfectly aligned about the vertical axis. This work also presents empirical equations that relate the net energy loss due to sliding under an elasto-plastic deformation as a function of the sliding distance. In addition, a load ratio of the horizontal reaction force to the vertical one is defined for frictionless sliding. Although this is analogous to the common definition of the coefficient of friction between sliding surfaces, it just contains the effect of energy loss in plasticity. The contact dimensions are obtained for different vertical interferences as sliding progresses. Comparisons are drawn between the FEA results of frictional and frictionless sliding. 3D modeling has been initiated to yield similar result parameters.

Urban development will continue to increase in Texas because of population growth and urban sprawl. Despite the desire for urbanization and expansion of the economy, this growth increases the amount of construction, which, if not properly managed, can increase non-point source pollution and threaten surface water quality. Therefore, Texas Department of Transportation (TxDOT) has approved and promoted the use of compost as a stormwater best management practice (BMP) during highway construction. The objectives of this study were to construct and calibrate an indoor rainfall simulator and to determine the effectiveness of using compost rather than conventional hydroseeding or topsoil to reduce erosion from disturbed soils. Runoff rates, interrill erosion, and interrill erodibility were determined and compared across five compost treatments following TxDOT specifications for compost applied as an erosion control and two control treatments of topsoil (TS) and hydroseeding (HS) applied at 5 cm depth. The simulator produced 89% uniformity using ten Veejet 80100 nozzles at a target rate of 100 mm h-1. The surface runoff was collected after 5 minutes of rainfall (first flush) and during the last 30 minutes of rainfall (steady-state). The first flush mean runoff for GUC-5 treatment was significantly higher than all other treatments. All other treatments; 50% woodchips and 50% compost blend (ECC-1.3, ECC-5), and hydroseeding (HS) had significantly lower runoff and erosion rates compared to topsoil (TS) and compost manufactured topsoil (CMT) at first flush and steady-state. Furthermore, there were no performance differences between 1.3 cm and 5 cm compost applications at first flush or steady-state. The results of this project indicate that particle size, soil moisture capabilities, and time at which rainfall is applied affect surface runoff. TxDOT specification of using ECC at 5 cm depth on a max of 3:1 slope should be reconsidered. An ECC application depth of 1.3 cm was effective in reducing first flush runoff and interrill erosion rates.

In this study, fracture grouting technique of saturated, granular soils of different fine content were investigated. Model tests were carried out by using fluid particulate grouts namely micro fine cement and ordinary portland cement grouts. Basically, relationships were obtained between soil conditions (grain size distribution, relative density, overburden stress) and grouting parameters (type of grout, grouting pressure, amount of injected grout, rheological properties of the grout or water/solids ratio). At the end of the tests the soil specimens were exposed and the final grout shapes were observed and correlated with the grouting parameters. Response of soil specimens to grouting process under different grouting pressures and grout compositions was analyzed. Amount of heave occurred at the top of the specimen during injections was recorded at each test. Micro fine cement grout and ordinary portland cement grout showed significant differences rheologically. Micro fine cement grout, with much higher Blaine fineness, lower specific gravity, lower viscosity and cohesion, lower bleed and filtration coefficients, made it possible to fracture the fine sandy soils of different fine content. Results of tests performed with micro fine cement grouts show that fracturing pressure generally decreases with an increase in the water content of the grout but generally increases as the fine content of the soil increases. A higher relative density of the soil increases the fracturing pressure significantly. The volumes of grout injected into soil specimens until fracturing show an increasing tendency as the water/solids ratio decrease. Ordinary portland cement grout, on the other hand, exposed to high pressure filtration during grouting in relatively clean sand and addition of some amount of kaolinite or fines is required to reduce the filtration percentages during grouting in order to fracture grout the sandy soil. Filtration due to high permeabilities results in accumulation of cement particles around the injection point and grouting tends to take a form similar to compaction grouting.

This work presents a three dimensional elastic-plastic model for two hemispherical bodies sliding across one another under various preset vertical interferences. In particular, steel-on-steel and aluminum-on-copper contact situations are considered. A finite element analysis is used for the model and the parameters to investigate include stresses, deformations, contact areas, and energy loss in sliding. Both frictional and frictionless sliding are investigated. In addidition to structural loads, electromagnetic loads are considered and a framework for a electromagneticlly, structurally, and thermally coupled model is investigated.

The analysis of wave propagation in solids with complex microstructures, and local heterogeneities finds extensive applications in areas such as material characterization, structural health monitoring (SHM), and metamaterial design. Within continuum mechanics, sources of heterogeneities are typically associated to localized defects in structural components, or to periodic microstructures in phononic crystals and acoustic metamaterials. Numerical analysis often requires computational meshes which are refined enough to resolve the wavelengths of deformation and to properly capture the fine geometrical features of the heterogeneities. It is common for the size of the microstructure to be small compared to the dimensions of the structural component under investigation, which suggests multiscale analysis as an effective approach to minimize computational costs while retaining predictive accuracy. This research proposes a multiscale framework for the efficient analysis of the dynamic behavior of heterogeneous solids. The developed methodology, called Geometric Multiscale Finite Element Method (GMsFEM), is based on the formulation of multi-node elements with numerically computed shape functions. Such shape functions are capable to explicitly model the geometry of heterogeneities at sub-elemental length scales, and are computed to automatically satisfy compatibility of the solution across the boundaries of adjacent elements. Numerical examples illustrate the approach and validate it through comparison with available analytical and numerical solutions. The developed methodology is then applied to the analysis of periodic media, structural lattices, and phononic crystal structures. Finally, GMsFEM is exploited to study the interaction of guided elastic waves and defects in plate structures.

The rapid growth of the microelectronics industry in the last decades made it possible to produce structures in the sub-micrometer scale on silicon chips and to reach an integration scale under 100 nm. Decreasing the size and increasing the complexity of these structures make a control of quality and defects investigation more difficult. During a long time ultrasound devices are being used for nondestructive investigation of materials, like ultrasound microscopes, scanning photo-acoustic microscopes or scanning electron-acoustic microscopes, where acoustic waves are generated by acoustic transducers, focused laser or electron beams, respectively. The aim of this work is to investigate more precisely the acoustic wave generation by pulsed and periodically modulated ion beams in different solid materials depending on the beam parameters and to demonstrate the possibility to apply an intensity modulated focused ion beam (FIB) for acoustic emission and for nondestructive investigation of the internal structure of materials on a microscopic scale. The combination of a FIB and an ultrasound microscope in one device can provide the opportunity of nondestructive investigation, production and modification of micro- and nanostructures simultaneously. The FIB spot size in modern systems is comparable with that of a focused electron beam and the penetration depth of ions with energy of 20-60 keV is lower than 100 nm. This makes it possible to reach a sub-micrometer resolution of a scanning ion acoustic microscope. On the other hand side a FIB with energy of 20-60 keV is a good tool which can be used for the fabrication of nanostructures using ion milling, implantation or ion beam assisted deposition techniques. The bulk ultrasound emission in a solid was investigated using a pulsed high energy ion beam focused on aluminum, copper, iron and silicon samples. Oxygen, silicon and gold ion beams were applied in charge states from 1+ to 4+ with the pulse duration of 0.5 - 4 µs and an energy of 1.5 - 10 MeV. Intensity of the detected acoustic waves shows a linear dependence on the energy of the incident ions, on the ion flux as well as on the pulse duration. No influence of the ion charge and ion mass to the emission of acoustic waves was observed. The ion acoustic effect was applied for a nondestructive material inspection using intensity modulated FIB providing by the IMSA-100 FIB system with an accelerating potential of 30-35 kV. The achieved lateral resolution of this scanning ion acoustic microscope is in the micrometer range depending on the sample material and the beam modulation frequency. The resolution can be improved by increasing the frequency. The maximal modulation frequency which was obtained at IMSA-100 is about 2 MHz corresponding to lateral resolution of 4-5 µm on silicon. Using this microscope, some images of integrated microstructures on a silicon chip were obtained using the lock-in technique for filtering of the signal from the noise and increasing of the total imaging time. The possibility to visualize near sub-surface structure was demonstrated. Due to the strong sputtering effect and the long time of irradiation the imaged structures were significantly damaged. Si2+, Ge2+, Ga+ and Au+ ions were used. All these ions are quite heavy and have high sputtering coefficients. Long-time imaging improves the quality of acoustic images, i. e. the signal-to-noise ratio is reduced with the square root from the pixel time, but leads to significant erosion of the imaged structure.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 182-188). Also available on the Internet.