Orientador: Eduardo Hochuli Vieira / Banca: Idelmo Rangel Garcia Júnior / Banca: Walter Leal de Moura / Resumo: Proposição: Este estudo teve como objetivo avaliar, através de estudo microscópico por análises histológica, histométrica e imunoistoquímica, o comportamento ósseo frente à presença de cimento de fosfato-carbonato de cálcio em defeitos experimentais. Materiais e Método: Foram confeccionados defeitos não-críticos em tíbias de 30 ratos machos adultos (Rattus norvegicus albinus, Wistar), em dois grupos, Controle e Tratado. As lâminas foram obtidas nos períodos de 10, 20 e 30 dias pósoperatórios e as imagens teciduais foram analisadas qualitativa e quantitativamente. Resultados: Não houve diferença estatística na área de neoformação óssea entre os grupos controle e tratado (P=0,258) e entre a expressão de RANK-L e OPG (P=0,589). Observou-se também áreas mínimas de invasão de tecido conjuntivo e periósteo com presença tardia do cimento em áreas distintas do defeito. Conclusão: De acordo com a metodologia aplicada, foi possível concluir que o uso de cimento de fosfato-carbonato de cálcio não alterou significativamente o processo de regeneração ósseo em tíbias de rato. / Abstract: Proposition: This study had as objective evaluates, through histological, histometric and imuno-histochemical microscopic analysis, the bone behavior face to the presence of calcium phosphate-carbonate cement in experimental defects. Materials and Method: Non-critical defects were made in tibias of 30 adult male rats (Rattus norvegicus albinus, Wistar), in two groups, Control and Treated. The slices were obtained in the periods of 10, 20 and 30 postoperative days. The snapped images were quantitative and qualitative analyzed. Results: There was not statistics difference in the bone formation area (AO) between the groups control and treated (P=0,258) and between RANK-L and OPG expressions (P=0,589). It was also observed minimal areas of invasion of conjunctive tissue and periosteum with presence of the cement in areas different of the defect. Conclusion: In agreement with the applied methodology, it was possible to conclude that the use of calcium phosphate-carbonate cement didn't alter significantly the process of bone repair in rat tibias. / Mestre

Carbonate sediments are often highly heterogeneous due to the numerous factors that control deposition. Understanding the processes and controls that are responsible for such complexity has, however, proved problematic. In addition, several of these processes are non-linear, so that depositional stratigraphies may consequently form complicated, perhaps even chaotic, geometries. Forward modelling can help us to understand the interactions between the various processes involved. Here a new three-dimensional forward model of carbonate production and deposition is presented, Carbonate GPM, which is specifically designed to test the interactions between the three main carbonate production controls: light intensity, wave power and carbonate supersaturation, the latter of which is unique to this model. The model also includes transport processes specific to the reef sediment only. The effect of supersaturation and reef transport is demonstrated by comparing the output of three, otherwise, identical runs. From these simulations the need to accurately model the flow of water around a reef system and to correctly take into the account the binding nature of reefal sediments can be seen. Analysis of the stratigraphy generated by changing the antecedent topography by 1m in one locality over a 50km square platform suggest that it may be impossible to predict in detail the stratigraphy of carbonate deposits due to its sensitivity to initial conditions or controlling parameters. This reinforces the conclusions reached using previous process models. However, unlike previous models, our model does not explicitly include nonlinear biological interactions as a control. Instead it shows that similar sensitive behaviour may originate from physicochemical processes alone. External factors, such as sea-level changes, will also influence the complex stratigraphy generated by the model. The effect of several different relative sea-level curves was assessed, each corresponding to a combination of three different hierarchies of sea-level oscillations. Large-scale external processes dominate internal processes, dampening their effect on stratigraphy. However, small-scale, high frequency external processes coupled with autocyclic processes do not show any discernable stratigraphic differences from autocyclcic processes alone. The model also produces an exponential cycle thickness distributions that are similar to those found in ancient deposits.

Carbonate rocks consider as significant reservoirs for hydrocarbon. More than 60% of the world's hydrocarbon is placed in carbonate reservoirs. Carbonate rocks are heterogeneous and contain complex pore system. This complexity causes the hydrocarbon recovery from these reservoirs difficult; having less than 35% of hydrocarbon is being recovered. The heterogeneity and the variation in pore system are a result of various depositional settings and successive diagenetic overprints. Diagenetic overprints account for most of the pore system complexity in subsurface. This project undertakes one of the important diagenetic processes, calcite cementation, which though to have major impact on reservoir quality. The project aims to better understand the controls on calcite cementation in five Lower Cretaceous Reservoirs, in particular the role of calcite cementation with relation to oil charge in reservoir quality. Other diagenetic processes were also asses including dolomitization, dissolution, micritization and chemical compaction. The five reservoirs (A, B, C, F & G) are from Field A which is located in Abu Dhabi, UAE. The reservoirs comprise of interbedded porous "Reservoir" and low porosity-permeability "Dense" limestones deposited in broad range of settings, ranging from restricted to open marine platform. Reservoir intervals are part of HSTs, deposited during higher sea level time. The dense intervals were deposited during TST and thought to be cemented early resulting in early compartmentalization in all reservoirs. The mMg/Ca and in-situ (SIMS) δ18OVPDB were measured through complete calcite cement stratigraphy obtained from equant, syntaxial and blocky calcite in all reservoirs. Both mMg/Ca and δ18OVPDB of oldest calcite cement zone are matching with published mMg/Ca and δ18OVPDB of Lower Cretaceous, suggesting precipitation from Lower Cretaceous seawater. The mMg/Ca and δ18OVPDB also vary from reservoir to another reflecting change in Cretaceous seawater. These data also coincide with trace element observations particularly Mn and Sr. All these parameters show fluctuations in Cretaceous seawater during 135-123Ma caused by global changes in climate and oceanic crust production rates. Lower reservoirs including F (133Ma) and C (130Ma) were more probably affected by the Hauterivian global cooling which resulted in higher δ18OVPDB in the early precipitated cements. Precipitation in upper Reservoir B (126Ma) was most likely affected by the abrupt warm episode just before the OAE1. Reservoir A (123Ma) precipitation may be affected by the Early Aptian cooling episode and the OAE1. Reservoir G is the only one not recording δ18OVPDB similar of Cretaceous seawater. Cementation in Reservoir G was affected by depleted δ18OVPDB fluids from early stage, perhaps hot, basinal waters. More interestingly, the mMg/Ca, δ18OVPDB Mn and Sr means of younger calcite cement zones which thought to be evolved during burial show similar trend to the oldest cement zones with various offsets. This suggests that calcite cement in each reservoir evolved in a relatively close system inferring by this that the reservoirs are compartmentalized. The compartmentalization is probably due to the sysedimentary or early cemented hardgrounds in the Dense Zones. The Dense Zones acted as seals for the reservoirs from early stage causing the later precipitated calcite cement which is diagenetically affected to behave in predictable and similar way. Moreover, calcite precipitation temperatures inferred from mMg/Ca and δ18OVPDB show progressive increase towards younger cement zones indicating fluid evolution with burial in also relatively close system. In-situ δ18OVPDB and oil inclusions suggest earlier oil charge in the shallower reservoirs compared with deeper reservoirs and coeval water leg. Consequently, cementation in the shallower reservoirs continued with lower rate and hence preserved some primary and secondary pores. Conversely, in the water leg cementation continue to occlude most of the pore spaces. Furthermore, early oil emplacement in the shallower reservoirs increased the cementation temperature of calcite in the oil leg to reach maximum precipitation temperatures of ~144˚C. Whereas, in the water leg and deeper reservoirs, cementation continued to a temperature of ~110˚C. Overall, reservoir quality in Thamama Group was affected by various diagenetic processes. Some have resulted in reservoir quality enhancement such as dolimitization which involves formation of microporosity as a result of replacive rhombic dolomite, dissolution particularly the late one which believed to be due organic acid, and micritization with yield microporosity particularly in Reservoir B. Open fractures might have also enhanced reservoir quality to some extent. Diagenetic events that have deteriorated reservoir quality include calcite and saddle dolomite cementation as well as stylolitization. Greater calcite cementation can be found in water leg compared with oil leg because oil thought to decrease cementation rate.

abstract: Variations of 238U/235U in sedimentary carbonate rocks are being explored as a tool for reconstructing oceanic anoxia through time. However, the fidelity of this novel paleoredox proxy relies on characterization of uranium isotope geochemistry via laboratory experimental studies and field work in modern analog environmental settings. This dissertation systematically examines the fidelity of 238U/235U in sedimentary carbonate rocks as a paleoredox proxy focusing on the following issues: (1) U isotope fractionation during U incorporation into primary abiotic and biogenic calcium carbonates; (2) diagenetic effects on U isotope fractionation in modern shallow-water carbonate sediments; (3) the effects of anoxic depositional environments on 238U/235U in carbonate sediments. Variable and positive shifts of 238U/235U were observed during U uptake by primary abiotic and biotic calcium carbonates, carbonate diagenesis, and anoxic deposition of carbonates. Previous CaCO3 coprecipitation experiments demonstrated a small but measurable U isotope fractionation of ~0.10 ‰ during U(VI) incorporation into abiotic calcium carbonates, with 238U preferentially incorporated into the precipitates (Chen et al., 2016). The magnitude of U isotope fractionation depended on aqueous U speciation, which is controlled by water chemistry, including pH, ionic strength, carbonate, and Ca2+ and Mg2+ concentrations. Based on this speciation-dependent isotope fractionation model, the estimated U isotope fractionation in abiotic calcium carbonates induced by secular changes in seawater chemistry through the Phanerozoic was predicted to be 0.11–0.23 ‰. A smaller and variable U isotope fractionation (0–0.09 ‰) was observed in primary biogenic calcium carbonates, which fractionated U isotopes in the same direction as abiotic calcium carbonates. Early diagenesis of modern shallow-water carbonate sediments from the Bahamas shifted δ238U values to be 0.270.14 ‰ (1 SD) higher than contemporaneous seawater. Also, carbonate sediments deposited under anoxic conditions in a redox-stratified lake—Fayetteville Green Lake, New York, USA— exhibited elevated δ238U values by 0.160.12 ‰ (1 SD) relative to surface water carbonates with significant enrichments in U. The significant U isotope fractionation observed in these studies suggests the need to correct for the U isotopic offset between carbonate sediments and coeval seawater when using δ238U variations in ancient carbonate rocks to reconstruct changes in ocean anoxia. The U isotope fractionation in abiotic and biogenic primary carbonate precipitates, during carbonate diagenesis, and under anoxic depositional environments provide a preliminary guideline to calibrate 238U/235U in sedimentary carbonate rocks as a paleoredox proxy. / Dissertation/Thesis / Doctoral Dissertation Geological Sciences 2018

abstract: The public has expressed a growing desire for more sustainable and green technologies to be implemented in society. Bio-cementation is a method of soil improvement that satisfies this demand for sustainable and green technology. Bio-cementation can be performed by using microbes or free enzymes which precipitate carbonate within the treated soil. These methods are referred to as microbial induced carbonate precipitation (MICP) and enzyme induced carbonate precipitation (EICP). The precipitation of carbonate is the formation of crystalline minerals that fill the void spaces within a body of soil. This thesis investigates the application of EICP in a soil collected from the Arizona State University Polytechnic campus. The surficial soil in the region is known to be a clayey sand. Both EICP and MICP have their limitations in soils consisting of a significant percentage of fines. Fine-grained soils have a greater surface area which requires the precipitation of a greater amount of carbonate to increase the soil’s strength. EICP was chosen due to not requiring any living organisms during the application, having a faster reaction rate and size constraints. To determine the effectiveness of EICP as a method of improving a soil with a significant amount of fines, multiple comparisons were made: 1) The soil’s strength was analyzed on its own, untreated; 2) The soil was treated with EICP to determine if bio-cementation can strengthen the soil; 3) The soil had sand added to reduce the fines content and was treated with EICP to determine how the fines percentage effects the strength of a soil when treated with EICP. While the EICP treatment increased the strength of the soil by over 3-fold, the strength was still relatively low when compared to results of other case studies treating sandy soils. More research could be done with triaxial testing due to the samples of the Polytechnic soil’s strength coming from capillarity. / Dissertation/Thesis / Masters Thesis Civil, Environmental and Sustainable Engineering 2018

Coral cover remains highest on patch reefs at the northern end of the Florida reef tract. The reasons for this trend are not well understood, but may be related to the protection from extreme variations in water quality parameters provided by the near constant presence of islands at the north extent of the Florida Keys. Three indices have been developed based on Foraminifera and sediment constituents. Two of the indices, the FORAM Index and the SEDCON Index, were developed to indicate the suitability of a reef environment for continued reef accretion. The third index, the Photic Index, is an assessment of photic stress on reefs based on incidence of bleaching in a species of Foraminifera, Amphistegina gibbosa, which is known to experience loss of algal endosymbionts similar to bleaching in corals. Patch reefs were sampled in Biscayne National Park, FL to assess sediment characteristics and foraminiferal assemblages, as well as to examine trends in the three indices. Sediments associated with a majority (59%) of reefs were coarse sands; muddy sediments were restricted to a few inner patch reefs that were isolated from the influence of Caesar's Creek, which flushes water from inside Biscayne Bay onto the open shelf. Unidentifiable grains predominated in the sediment constituents, along with calcareous algae and molluskan debris. Shells from 82 genera of Foraminifera were identified in the sediments. Quinqueloculina was the most consistently common genus. Percent mud was the single most influential measured variable on the distribution of both sediment constituents and foraminiferal assemblages. Analysis of bleaching in the foraminifer Amphistegina gibbosa revealed that photo-oxidative stress was chronic at 94% of the sites. Patterns of FORAM and SEDCON Index values and their similarity to temperature, salinity, and percent mud distributions show that Caesar's Creek is affecting the benthic community in its immediate vicinity by providing flow that limits the accumulation of mud and potentially other anthropogenic stressors. Overall this study suggests that the reefs in this area are marginal for continued reef growth. A more detailed study of water quality through Caesar's Creek should be conducted to determine exactly how it is affecting the reefs in Biscayne National Park.

Monitoring of Bear Lake was conducted in 1981 and 1982 to describe the current limnology and trophic state of the lake. The nutrientt loadings of various parameters were measured from April, 1981 through June, 1982. The rate of coprecipitation of phosphorus was determined for different initial phosphorus concentrations by use of non-algal assays. Algal bioassays with Selenastrum capricornutum were used to determine the reduction in potential algal biomass as a result of the coprecipitation of phosphorus. The lake exhibit-.ed chemical characteristics indicative of mesotrophy or eutrophy. Total phosphorus values averaged 11μg/1 for 1981 and 20 μg/1 for 1982. A hypolimnetic accumulation of phosphorus was also not:ed for the stratified periods. Addittionally, hypolimnetic oxygen deficit values were indicative of mesotrophy in 1981 and eutrophy in 1982. The chlorophyll concentrations were characteristic of oligotrophic conditions during both years however. Phosphorus was found to be limiting production approximately 85% of the year. The Bear River Contributed approximately 60% of the total phosphorus loading to the lake in 1981 and 50% in 1982. Overall, the total phophorus loading increased 195% between the dry year, 1981, and the wet year, 1982. Vollenweider's (1976) phosphorus loading model described the loading to Bear Lake as indicative of mesotrophic conditions in 1981 and eutrophic conditions in 1982. Calcium and magnesium concentrations fluctuated widely throughout the year. The Mg:Ca molar ratio varied from 1:1 in the spring to 3.5:1 in the fall. Total hardness values did not vary in response to the changing ionic concentrations and this was attributed to preferential replacement of precipitated calcium by the Bear River inflow. Non-algal assays quantified the removal of phosphorus by coprecipitation at increasing initial phosphorus by concentration. The rate of removal initial decreased substantially as phosphorus levels increased with a shift in reaction order from second order to first order noted at approximately 50 μg/1. Predictive models were derived from the initial assays and verified with data from a separate experiment which use filtered Bear Lake water. The models accurately predicted the amount of phosphorus removed by coprecipitation at all phosphorus levels. Algal bioassays in synthetic Bear Lake and soft-water media were used to evaluate the efficiency of the coprecipitation mechanism when in competition with algae for phosphorus. An average reduction in biomass of 40% was noted between the media at similar nutrient levels.

Photolysis of nitrate ion in the natural environment produces NO, NO2, and O3, releasing these toxic gases into the atmosphere. Work done by other groups has shown ionic strength dependence of the ratio of products from photolysis of aqueous nitrate ion. To better understand the kinetic mechanisms of nitrate photolysis, the effects that ionic strength in solution have on nitrate ion symmetry breaking are needed. Different solvation environments induce nitrate bonding motifs that may be correlated to the product ratio. Fourier-transform infrared spectra of aqueous nitrate–ion solutions were obtained over a range of temperatures for several total electrolyte concentrations. The electric fields (arising from water molecules and ions in solution) in aqueous potassium nitrate solution distort the trigonal planar shape of the nitrate ion, which may favor a specific initial path of the decomposition of nitrate during photolysis. Van’t Hoff plots of the relative peak areas corresponding to the formally-degenerate asymmetric stretching mode reveal the relative energies of the two solvation geometries. The difference in energy between the two geometries is linearly proportional to the ionic strength of the solution. Electronic structure calculations suggest that the more symmetric geometry has an increased stability relative to the less-symmetric geometry in high ionic strength solutions. Thus, the relative amounts of the nitrate ion solvation geometries can be correlated to the amount of products produced during photolysis to help explain the ionic-strength dependence of the product yields. Nitrate geometries at the water—CCl4 interface and aqueous carbonate ion bonding motifs are being investigated to identify pure-water effects. Preliminary results suggest that the more symmetric geometry nitrate is stabilized at the water—CCl4 interface and the lesssymmetric carbonate solvation geometry has an increased stability relative to the more symmetric geometry in high ionic strength solutions.

Acid deposition forms when emission-derived sulfur dioxide and nitrogen oxides interact with precipitation and was particularly severe in the northeastern US. Effects of acid deposition include declining soil quality due to low pH and base cation leaching, which subsequently altered the composition of soil solution, ground water (GW) and eventually stream water. Because of the high buffering capacity of carbonates, watersheds underlain by carbonate rich rocks have received limited attention in acid deposition studies, however, carbonate weathering by strong anthropogenic acids can increase atmospheric CO2 levels. Emission reductions due to the Clean Air Act and Amendments has led to a substantial reduction of acid deposition and many ecosystems are now recovering and stream water exports contain lower concentrations of acid anions and base cations. However, the effects of recovery on watershed soil, soil solution, and GW composition, which potentially varies with landscape position, are not well constrained. The objective of this study was therefore to investigate links between soils and water composition in a watershed with important carbonate contents in the underlying rock, the Sleepers River Research Watershed (SRRW), using long-term datasets that span the recovery period. Temporal trends (1991-2015) for acid anions (sulfate and nitrate), pH, base cations (Ca, Na) and Si were investigated for stream water and trends with time, depth, and landscape position (hilltop, hillslope, and riparian zone) for the same solutes were assessed in GW and soil solution (2004-2013). Furthermore, soil elemental composition and mineralogy in archived (1996) and modern (2017) soil samples were analyzed to investigate changes in soil composition due to base cation leaching and carbonate weathering with time and landscape position. Results indicate that SRRW is indeed recovering from acidification as evidenced by declining sulfate content and rising pH in stream water, GW, and soil solution. Additionally, Ca typically derived from carbonate weathering decreased progressively with time in GW and showed signs of decreasing in soil solution at various landscape positions due to reduced leaching. However, Ca in stream water shows slight increases, likely due to Ca released from riparian soil stores. Spatial heterogeneity is especially pronounced in headwater catchments with steep topography as evidenced by changes in solution and soil composition along hillslopes. In addition to the paper submitted for publication (Chapter 2) to Frontiers in Earth Science – Biogeochemistry this thesis includes i) a background and literature review to inform the reader on pertinent topics, ii) an appendix containing additional soil data with figures, iii) and an appendix with additional aqueous phase data with figures.

Deposition of calcium carbonate (CaCO3) and calcium sulfate (CaSO4) causes serious processing problems and limits the productivity of seawater reverse osmosis (RO) desalination. The interactions between CaSO4 and CaCO3 in the dynamic seawater RO systems have been neglected previously because conventional studies mainly focused on individual compounds or mixed compounds in batch systems. The present work evaluates composite fouling behavior of CaSO4 and CaCO3 in a dynamic RO unit. The fouling experiments were performed at constant pressure and velocity by a partial recycling mode which permeate was withdrawn from the system during the recirculation of retentate to simulate the increasing of water recovery level. The fouling phenomena were monitored by the decline of flux. Scanning electron microscopy (SEM) with a combination of elemental dispersive x-ray microanalysis (EDS), and x-ray powder diffraction (XRD) was used to identify the morphological features, chemical compositions and crystalline phases of foulants. The interactions of CaSO4 and CaCO3 were investigated by the comparison between individual CaSO4 or CaCO3 fouling and composite fouling, and by varying SO42-/HCO3- molar ratio of the feed. A recently developed approach, Scaling Potential Index (SPI) incorporated with measured concentration polarization modulus (CP), for assessing the fouling tendency of inorganic salts on the membrane surface was validated in the dynamic tests. In addition, the effectiveness of two generic scale inhibitors, polyacrylic acid (molecular weight =2100, PA) and sodium hexametaphosphate (SHMP) were evaluated. Some of the highlights of the obtained results are as follows: ??????The precipitation kinetics, morphology and adhesive strength of composite scales were different from pure precipitates ??????CaSO4 precipitated as gypsum while CaCO3 precipitated as two crystalline phases: calcite and aragonite ??????The crystalline phases as well as precipitation kinetics were affected by SO42-/HCO3- ratio ??????Scaling Potential Index was able to predict the fouling tendency of CaSO4 and CaCO3 accurately ??????The dosage of PA and SHMP was effective to mitigate fouling Results of this work are significant, not only because they have made contribution to the fundamental understanding of composite inorganic fouling in RO membrane systems which was ignored previously, but also because they may play a key role in the development of scale control.