ABSTRACT COMPARISON OF ANALYSIS METHODS OF EMBEDDED RETAINING WALLS HARMANDAR, Serkan M.S., Department of Civil Engineering Supervisor : Prof. Dr. Yener &Ouml / zkan Co -Supervisor : Dr. Oguz &Ccedil / aliSan December 2006, 123 pages In this study a single-propped embedded retaining wall supporting a cohesionless soil is investigated by four approaches, namely limit equilibrium, subgrade reaction, pseudo-finite element and finite element methods. Structural forces, such as strut loads, wall shear forces, bending moments are calculated by each method and results are compared. The analyses are carried for for three values of internal friction angle of soil / 30o, 35o, and 40o. Effects of modulus of soil elasticity of the backfill and wall stiffness on structural forces are investigated by using different values for these parameters. It is found that, in those of obtained by, limit equilibrium approach results in embedment depth greater than other methods. Minimum strut loads for the same soil and structure parameters are obtained by limit equilibrium method. An increase of Young&rsquo / s modulus of the soil results in decrease of the strut loads.

Finite element method and strip method are two widely used techniques for analyzing steel plate shear wall (SPSW) systems. Past research mostly focused on the prediction of lateral load capacity of these systems using these numerical methods. Apart from the lateral load carrying capacity, the lateral stiffness of the wall system needs to be determined for a satisfactory design. Lateral displacements and the fundamental natural frequency of the SPSW system are directly influenced by the lateral stiffness. In this study the accuracy of the finite element method and strip method of analysis are assessed by making comparisons with experimental findings. Comparisons revealed that both methods provide in general solutions with acceptable accuracy. While both methods offer acceptable solutions sophisticated computer models need to be generated. In this study two alternative methods are developed. The first one is an approximate hand method based on the deep beam theory. The classical deep beam theory is modified in the light of parametric studies performed on restrained thin plates under pure shear and pure bending. The second one is a computer method based on truss analogy. Stiffness predictions using the two alternative methods are found to compare well with the experimental findings. In addition, lateral stiffness predictions of the alternate methods are compared against the solutions provided using finite element and strip method of analysis for a class of test structures. These comparisons revealed that the developed methods provide estimates with acceptable accuracy and are simpler than the traditional analysis techniques.

A numerical study has been undertaken to evaluate the response of dual systems which consist of steel plate shear walls and moment resisting frames. The primary objective of the study was to investigate the influence of elastic base shear distribution between the wall and the frame on the global system response. A total of 10 walls and 30 wall-frame systems, ranging from 3 to 15 stories, were selected for numerical assessment. These systems represent cases in which the elastic base shear resisted by the frame has a share of 10%, 25%, or 50% of the total base shear resisted by the dual system. The numerical study consisted of 1600 time history analyses employing three-dimensional finite elements. All 40 structures were separately analyzed for elastic and inelastic response by subjecting to the selected suite of earthquake records. Interstory drifts, top story drift, base shears resisted by the wall and the frame were collected during each analysis. Based on the analysis results, important response quantities such as the response modification, the overstrength, the displacement amplification and ductility reduction factors are evaluated herein. Results are presented in terms of several measures such as the interstory drift ratio and the top story drift ratio. A discussion related to the influence of load share on the response factors is given.

This is the report of a Life Cycle Assessment (LCA) study on some masonry wall types. As the starting point, literature on masonry materials, techniques and possible end-of-life scenarios were examined that are needed for the formulation of a LCA study. Prevalent masonry types were detected as fired clay brick, AAC block, natural stone, mud brick as well as prevalent end-of-life cases as landfill, reuse and recycling. Additionally, an overview of the literature on Environmental Impact Assessment (EIA) was presented in order to detect a framework for the structure of a LCA study. After the collection of all needed information, several possible life cycle scenarios were formulated in a realistic manner for each stated masonry type. Obtained information was applied to a LCA evaluation software product named SimaPro life cycle inventory software (PR&eacute / Consultants, 2012). By means of the software product, general scores of environmental impact for all alternatives were obtained. Besides analyzing and comparing the scores, basic reasons behind the results were discussed in terms of similarity and difference. The results reveal that when the requirements shaping the wall are clearly described, the most and the least environmental friendly wall types are detectable. During the study two main scopes, such as commonly used wall thicknesses and thicknesses for thermal insulation were described and several types of walls with life cycle alternatives were labeled as the most or the least harmful to nature. To conclude, although it is not reasonable to point out one type of masonry as the least harmful one for any cases, the conditions of each case detect the most and the least v harmful type of masonry walls. Nevertheless, the relatively low environmental impact of mud brick masonry is striking. Therefore the environmental friendly aspect of mud brick masonry is underlined &ndash / one more time- by the results of this study.

Atherosclerosis is a disease of the cardiovascular system where a stenosis may develop in an artery which is an abnormal narrowing in the blood vessel that adversely affects the blood flow. Due to the constriction of the blood vessel, the flow is disturbed, forming a jet and recirculation downstream of the stenosis. Dynamic pressure fluctuations on the inner wall of the blood vessel leads to the vibration of the vessel structure and acoustic energy is propagated through the surrounding tissue that can be detected on the skin surface. Acoustic energy radiating from the interaction of blood flow and stenotic blood vessel carries valuable information from a diagnostic perspective. In this study, a constricted blood flow is modeled by using ADINA finite element analysis software together with the blood vessel in the form of a thin cylindrical shell with an idealized blunt constriction. The flow is considered as incompressible and Newtonian. Water properties at indoor temperature are used for the fluid model. The diameter of the modeled vessel is 6.4 mm with 87% area reduction at the throat of the stenosis. The flow is investigated for Reynolds numbers 1000 and 2000. The problem is handled in three parts which are rigid wall Computational Fluid Dynamics (CFD) solution, structural analysis of fluid filled cylindrical shell, and Fluid Structure Interaction (FSI) solutions of fluid flow and vessel structure. The pressure fluctuations and consequential vessel wall vibrations display broadband spectral content over a range of several hundred Hz with strong fluid-structural coupling. Maximum dynamic pressure and vibration amplitudes are observed around the reattachment point of the flow near the exit of the stenosis and this effect gradually decreases along downstream of flow. Results obtained by the numerical simulations are compared with relevant studies in the literature and it is concluded that ADINA can be used to investigate these types of problems involving high frequency pressure fluctuations of the fluid and the resulting vibratory motion of the surrounding blood vessel structure.

The soil-borne filamentous fungus Trichoderma virens is a biocontrol agent with a well known ability to produce antibiotics, parasitize pathogenic fungi and induce systemic resistance in plants. Here we report the identification, purification and characterization of an elicitor secreted by T. virens; a small protein designated Sm1 (small protein 1). Confrontation and disk assays demonstrated that Sm1 lacks toxic activity against plants and microbes. Native, purified Sm1 triggers production of reactive oxygen species in rice (Oryza sativa) and cotton (Gossypium hirsutum), and induces the expression of defense related genes both locally and systemically in cotton. Gene expression analysis revealed that SM1 is expressed throughout fungal development and is transcriptionally regulated by nutrient conditions and the presence of a host plant. When T. virens was co-cultured with cotton in an axenic hydroponic system, SM1 expression and secretion of the protein was significantly higher than when the fungus was grown alone. These results indicate that Sm1 is involved in plant-Trichoderma recognition and the induction of resistance by activation of plant defense mechanisms. Following the cloning of SM1, strains disrupted in or over-expressing SM1 were generated. Targeted gene disruption revealed that SM1 was not involved in fungal development. Expression of defense related genes in cotton and maize (Zea mays) was induced locally and systemically following colonization by T. virens in the hydroponic system. Low levels of expression of cotton or maize defense genes were found when seedlings were grown with a T. virens strain disrupted in SM1, ssupporting the Sm1-elicitor hypothesis. Additionally, unique proteins in T.virens-cotton/maize interaction were identified. Thus, the induction of defense responses in two agriculturally important crops appears to be microbially mediated. Functional analysis of a cell wall degrading enzyme, beta-1,6-glucananse (Tv-bgn3) from T. virens, demonstrated involvement of this enzyme indirectly in mycoparasitic activity of T. virens. Protein extracts from the strain disrupted in TV-BGN3 displayed reduced capability to inhibit growth of Pythium ultimum as compared to the wild-type. Additionally, protein extracts from the strains co-expressed with TV-BGN2 (beta-1,3-glucananse) from T. virens showed a significantly increased capability to inhibit growth of P. ultimum and Rhizoctonia solani hyphae.

Mutants showing developmental hyper-responsiveness to limited light were screened and designated as seedlings hyper-responsive to light (shl). These mutants showed an etiolated phenotype similar to wild type in the dark, yet had shorter hypocotyls, larger cotyledons, and more advanced development of true leaves than wild type in low light. The SHL genes act (genetically) as light-dependent negative regulators of photomorphogenesis, possibly in a downstream signaling or developmental pathway that is shared by the major photoreceptor genes (CRY1, PHYA, and PHYB) and other photoreceptors (CRY2, PHYC, PHYD, and PHYE). shl1 and shl2 were shown to be partially dependent on HY5 activity for their light-hyperresponsive phenotypes. shl1-1 showed a defect in responding to auxin in its root development in both white and yellow light conditions, and showed a defect in responding to auxin in hypocotyl elongation in yellow light. Compared to wild type, both shl1-1 and shl2-2 showed increased hypocotyl length in response to cytokinin in white light. Gibberellin (GA) partially recovered shl1-1 mutant phenotype in yellow light, whereas showed no effect on hypocotyl elongation of shl2-2 in this light condition. These altered responses of shl1-1 and shl2-2 to multiple phytohormones in different light regimes suggests that cross-talks among light and hormones regulate SHL1 and SHL2. One of the SHL genes, SHL2 was cloned by map-based positional cloning and shown to be allelic to the previously identified locus designated murus3(mur3) and katamari1(kam1). MUR3/KAM1 encodes a XyG galactosyltransferase. Sequence analysis demonstrated that our original EMS generated reference allele shl2-2 is probably not a null mutant, therefore the phenotypes of T-DNA insertion null mutant in SHL2, SALK_074435 were studied in different light conditions. Unlike shl2-2, SALK_074435 had a slightly short hypocotyl phenotype in the dark (though not to the extent of the det/cop/fus mutants). A consideration of the phenotypes and molecular lesions of shl2-2 and mur3 alleles, along with the phenotypes of null alleles kam1 and SALK_74435, suggests that SHL2/MUR3/KAM1 may be involved in hypocotyl elongation in low light through the modification of xyloglucan in the plant cell wall, and may play a role in hypocotyl elongation in the dark through proper organization of the endomembrane.

The first study researched turbulent forced convective heat (mass) transfer down- stream of blockages with round and elongated holes in a rectangular channel. The blockages and the channel had the same cross section, and a distance equal to twice the channel height separated consecutive blockages. Naphthalene sublimation experiments were conducted with four hole aspect ratios (hole-width-to-height ratios) and two hole-to-blockage area ratios (ratios of total hole cross-sectional area to blockage area). The effects of the hole aspect ratio, for each hole-to-blockage area ratio, on the local heat (mass) transfer distribution on the exposed primary channel wall between consecutive blockages were examined. Results showed that the blockages with holes enhanced the average heat (mass) transfer by up to 8.5 and 7.0 times that for fully developed turbulent flow through a smooth channel at the same mass flow rate, respectively, in the smaller and larger hole-to-blockage area ratio (or smaller and larger hole diameter) cases. The elongated holes caused a higher average heat (mass) transfer and a larger spanwise variation of the local heat (mass) transfer on the channel wall than did the round holes. The second study explored the heat transfer enhancement for pool boiling on nano-structured surfaces. Experiments were conducted with three horizontal silicon surfaces, two of which were coated with vertically aligned multi-walled carbon nanotubes (MWCNT) with heights of 9 and 25 ¹m, respectively, and diameters between 8 and 15 nm. The MWCNT arrays were synthesized on the two silicon wafers using chemical vapor deposition. Experimental results were obtained over the nucleate boiling and film boiling regimes under saturated and sub-cooled (5±C and 10±C) boiling conditions. PF-5060 was the test fluid. Results showed that the MWCNT array with a height of 25 ¹m enhanced the nucleate and film boiling heat fluxes on the silicon surface by up to 380% and 60%, respectively, under saturated boiling conditions, and by up to 300% and 80%, respectively, under 10±C sub-cooled boiling conditions, over corresponding heat fluxes on a smooth silicon surface. The MWCNT array with a height of 9 ¹m enhanced the nucleate boiling heat flux as much as the taller array, but did not significantly enhance the wall heat flux in the film boiling regime.

Contamination of soil/groundwater supplies by gasoline and other petroleum-derived hydrocarbons released from underground storage tanks (USTs) is a serious and widespread environmental problem. Corrosion, ground movement, and poor sealing can cause leaks in tanks and associated piping. Petroleum hydrocarbons contain methyl tertiary-butyl ether (MTBE) (a fuel oxygenate), benzene, toluene, ethylbenzene, and xylene isomers (BTEX), the major components of gasoline, which are hazardous substances regulated by many nations.The objective of this proposed study is to assess the potential of using a passive in situ oxidation barrier system. This passive active barrier system has advantages over conventional systems including less maintenance, cost-effectiveness, no above-ground facilities, no groundwater pumping and reinjection, and groundwater remediation in situ. The oxidation barrier system included a persulfate-releasing barrier, which contains persulfate-releasing materials. The slow-released persulfate would oxidize MTBE and benzene in aquifer. The persulfate-releasing materials would release persulfate when contacts with groundwater, thus oxidizes the MTBE and benzene. In the first part of this study, bench scale experiment was also performed to produce the persulfate-releasing materials high persulfate-releasing rate. The components of the persulfate-releasing materials and optimal concentrations of those components were determined in this study. Results indicate that the highest persulfate releasing rate can be obtained when the mass ratio of cement/sand/water was 1.4/0/0.7. Result obtained from the persulfate-releasing materials test and bench-scale were used for the design and operation of the following column experiments. Results from the column experiment indicate that approximately 98% of MTBE and 99% of benzene could be removed during the early persulfate-releasing stage. Results also reveal that the produced oxidation byproducts of MTBE, tert-butyl formate (TBF) and tert-butyl alcohol (TBA), can also be produce an acetone. Results from this study suggest that extra Fe(II) would cause the decrease in oxidation rates due to the reaction of sulfate with Fe(II). Results show that the parameters, which would affect the oxidation rate include persulfate concentration, oxidant reduction potential (ORP), conductivity, sulfate concentration, and contaminant concentration. The proposed treatment scheme would be expected to provide a more cost-effective alternative to remediate MTBE and other petroleum-hydrocarbon contaminated aquifers. Knowledge obtained from this study will aid in designing a persulfate oxidation system for site remediation.

Atherosclerosis is a multifactoral inflammatory disease that occurs in predisposed locations in the vasculature where blood flow is disturbed. In vitro studies have implicated reactive oxygen species as mediators of mechanotransduction leading to inflammatory protein expression and ultimately atherogenesis. While these cell culture-based studies have provided enormous insight into the effects of WSS on endothelial biology, the applicability to the in vivo setting is questionable. We hypothesized that low magnitude oscillatory WSS acts through reactive oxygen species (ROS) to increase expression of inflammatory cell adhesion molecules leading to the development of atherosclerotic lesions. The overall objective for this thesis was to develop an in vivo flow model that produces low magnitude oscillatory WSS which could be used to investigate the in vivo molecular mechanisms of mechanotransduction. We created a novel aortic coarctation model using a shape memory nitinol clip. The clip reproducibly constricts the aorta creating a narrowing of the lumen resulting in a stenosis. This mechanical constraint produces a region of flow separation downstream from the coarctation. We have characterized the coarctation in terms of the efficacy, pressure loss, and fluid dynamics. We then measured the endothelial response of shear sensitive redox and inflammatory markers. Lastly, we utilized genetically modified mice and mice treated with pharmacological inhibitors to investigate the mechanisms involved in the expression of WSS induced inflammatory and redox markers. We found that inducing a coarctation of the aorta using a nitinol clip uniquely created a hemodynamic environment of low magnitude oscillatory WSS without a significant change in blood pressure. Using this model we found that the in vivo endothelial phenotype associated with acutely disturbed flow was characterized by increased production of superoxide and increased expression of select inflammatory proteins. In comparison, the phenotype associated with chronically disturbed flow was characterized by a more modest increase in superoxide and increased levels of multiple inflammatory proteins. We determined that in regions of acutely disturbed flow in vivo, VCAM-1 expression was not modulated by reactive oxygen species. Additionally, p47 phox-dependent NADPH Oxidase activity does not have a functional role in WSS induced superoxide generation in the endothelium. In summary, we have created a novel murine model of low magnitude oscillatory WSS that can be used to investigate the in vivo molecular mechanisms associated with atherogenesis. While previous data obtained in vitro indicated that depletion of an individual ROS was sufficient to inhibit flow-induced inflammatory protein expression, our findings, to the contrary, showed that antioxidant treatment in vivo does not inhibit shear-dependent inflammatory protein expression. Our results suggest that atherogenesis in the in vivo environment is significantly more complicated than the in vitro environment and that parallel pathways and compensatory mechanisms are likely activated in vivo in response to WSS. These results could have significant implications in the efficacy of antioxidant treatment of atherosclerosis and could explain the complexity of results observed in clinical trials.