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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Processamento por infusão a vácuo de compósitos espessos aramida/epóxi e análise do desempenho sob impacto

Nunes, Stephanie Gonçalves January 2018 (has links)
Em aplicações que requerem solicitações de impacto, compósitos de matriz polimérica reforçados com fibra de aramida se destacam, principalmente em relação aos metais, devido a propriedades como alta resistência e rigidez específicas, que dão origem a sistemas mais leves e de alta performance. Quando voltados para aplicações de impacto, principalmente a alta velocidade, tais compósitos são, em sua maioria, moldados por compressão ou autoclave, a partir de pré-impregnados. No entanto, tais combinações de processamentos e matéria-prima acarretam em estruturas de elevado custo, tornando a infusão a vácuo uma opção atrativa, além de permitir a obtenção de peças grandes e complexas, dimensionalmente acuradas e partes integradas. Porém, a obtenção de um compósito espesso reforçado por fibra de aramida com elevado desempenho ao impacto por tal método de fabricação ainda é um desafio. Neste contexto, este trabalho aborda o efeito da espessura no processamento por infusão a vácuo de compósitos aramida/epóxi e seu desempenho em aplicações que requerem solicitações de impacto (baixa e alta velocidade) Para isso, foram produzidos compósitos com 5, 8, 13, 18, 23 e 28 camadas de aramida e caracterizados por ultrassom C-scan, microscopia ótica, densidade, teor de constituintes, testes mecânicos (flexão, short beam e indentação quase-estática) e cargas de impacto de baixa e alta velocidade (drop-weight e balístico). Todos os compósitos apresentaram boa homogeneidade na distribuição da matriz ao longo do reforço, com um teor de fibra de ≈60%, e valores de resistência short beam elevados (17,3 - 23,6 MPa). A performance sob impacto (baixa e alta velocidade) foi comparável à de compósitos fabricados por compressão ou autoclave, tendo os compósitos a partir de 18 camadas resistido ao projétil 9 mm Luger FMJ e o de 28 camadas resistido ao projétil .357 Magnum FMJ, podendo ser classificados como nível FB2 e FB3, respectivamente, de acordo com a norma europeia EN 1522. Portanto, o processamento de infusão a vácuo mostrou ser uma alternativa adequada para produzir compósitos espessos de aramida/epóxi (até 12 mm), substituindo rotas de processamento mais caras. / In applications that require impact solicitations, polymer matrix composites reinforced with aramid fiber stand out, especially in relation to metals, due to properties such as high specific strength and stiffness, which give rise to lighter and high-performance systems. When used for impact applications, especially at high speed, such composites are mostly molded by compression or autoclaved, from prepregs. However, such combinations of processing and raw material lead to high cost structures, making vacuum infusion an attractive option, as well as allowing the production of large, complex, dimensionally accurate and integrated parts. Nonetheless, obtaining a thick composite reinforced by aramid fiber with high impact performance by such manufacturing method is still a challenge. In this context, this work addresses the effect of the thickness in the vacuum infusion processing of aramid/epoxy composites and its performance in applications that require impact solicitations (low and high speed) For this, composites with 5, 8, 13, 18, 23 and 28 layers of aramid were produced and characterized by ultrasonic C-scan, optical microscopy, density, constituent content, mechanical tests (flexion, short beam and quasi-static indentation) and low- and high-speed impact loads (drop-weight and ballistic). All composites presented good homogeneity in the matrix scattering along the reinforcement, with a fiber content of ≈ 60%, and high short beam resistance values (17.3 - 23.6 MPa). The performance under impact (low and high speed) was comparable to that of composites processed by compression or autoclave, the composites with 18 layers resisted to the 9 mm Luger FMJ projectile and the one with 28 layers resisted to the .357 Magnum FMJ projectile, being classified as level FB2 and FB3, respectively, according to the European standard EN 1522. In summary, vacuum infusion processing proved to be a suitable alternative to produce thick aramid/epoxy composites (up to 12 mm), replacing more expensive processing routes.
62

Proyecto SANI / Project SANI

Casas Ormeño, Camila Alexandra, Ortiz Nuñez, Carlos Eduardo, Prado Barboza, Ximena Alexandra, Salazar Dias, Fiorella del Pilar, Sarmineto Barrantes, Adriana Stefhany 25 February 2020 (has links)
El presente proyecto de una infusión 100% natural a base de hoja de Jamaica, piña deshidratada y canela, que ayuda a las mujeres a combatir los molestos síntomas de la menstruación, tales como el dolor de cabeza, los cólicos y la ansiedad. La base de nuestro filtrante tiene propiedades anticoagulante, antioxidante y de relajación. En el presente trabajo se dará a conocer cómo fue identificado el problema y cómo detectamos la solución, para quienes y cómo acercarnos a ellas. Se encontró que las mujeres tienen una baja productividad en el trabajo o en los estudios cuando se encuentran en su periodo menstrual. Por ultimo, validamos nuestras hipótesis mediante entrevistas personales y focus grup. Para poder poner en marcha este proyecto se hizo un análisis profundo de la industria como los consumidores, proveedores, entre otros. Así mismo, se realizaron planes para las diferentes áreas: Estratégico, Operaciones, Marketing, RRHH, Responsabilidad Social, Financiero. Estos planes tienen las estrategias que usaremos para la viabilidad de la empresa. Tuvimos una inversión inicial de S/. 83,451 en el primer año, la utilidad neta del año 1 es de –S/. 58,540, para el segundo año S/. 272,438 y por último en el año 3 S/. 238,315. / The present project of a 100% natural infusion based on jamaica leaf, dehydrated pinacapple and cinnamon, which helps women combat the annoying symptoms of menstruation, such as headache, cramps and anxiety. The base of our filter has anticoagulant, antioxidant and relaxation properties. In the present work it will be announced hoy the problem was identified and how we detected the solution, for whom and hoy to approach them. It was found that women have low productivity at work or in studies when they are their menstrual period. Finally, we validete our hypotheses through personal interviews and focus groups. In order to implement this project, an in-depth analysis of the industry was carried out, such as consumers, suppliers, amog others. Likewise, plans were made for the different areas: Strategic, Operations, Marketing, Human Resources, Social Responsability, Financial. These plans have the strategics that we will use for the viability of the company. We had an initial investment of S/. 83,451 in the first year, the net income of year 1 is –S/. 58,540, for the second year S/. 272,438 and finally in the year 3 S/. 238,315. / Trabajo de investigación
63

Compatibility of Intravenous N-acetylcysteine and Ondansetron

Sergent, Sophia, Kennard, Ben, Tubolino, Michelle, Brown, Stacy, Thigpen, Jim 25 April 2023 (has links)
Due to the need for concurrent use of N-acetylcysteine (NAC) and ondansetron in the event of acetaminophen overdose, a Y-site intravenous (IV) apparatus for these drugs would be practical. It is known that nausea and vomiting are common side effects of both acetaminophen overdose and NAC administration. Current standard patient care using NAC involves interruption of IV NAC infusion to give an IV bolus dose of ondansetron, which creates an unnecessary opportunity for healthcare staff errors and patient complications. To evaluate the IV compatibility of NAC and ondansetron, medical grade tubing was connected via a closed-circuit IV pump with separate channels. Doses of NAC were circulated in individual channels based on weight-based dosing protocols (30-kg and 100-kg patient does). Ondansetron (4 mg) was introduced into the flow of NAC using the Y-site. Samples of the circulated solutions were gathered in triplicate at time points of 10, 20, and 30 minutes after combination of ondansetron and NAC. Concentrations of NAC were quantified using a validated high performance liquid chromatography (HPLC) method with ultraviolet (UV) detection. Once the collected samples underwent HPLC-UV analysis, data was produced that showed promise for compatibility between ondansetron and NAC with Y-site infusions. Comparison of NAC concentrations for the channels with and without ondansetron yielded no statistically significant difference between the treatments (p-value of 0.05). From this experiment, we concluded that introduction of ondansetron into the flow of NAC IV would not impact NAC concentration. As mentioned before, this study was conducted using only two doses in vitro, which may be a point for further exploration of a varied number of N-acetylcysteine doses.
64

Determination of Triacylglycerols in Edible Oils by Infusion ESI/MS and ESI/MS/MS

Asfaw, Biritawit 09 1900 (has links)
<p> Edible oils consist primarily of triacylglycerols (or TAGs), which are triesters of glycerol and fatty acids. Determination of the TAG compositions of edible oils is becoming more important, given the economic value of these oil products and the increasing incidence of adulterating high quality oils with poorer quality oils. In this study we report the development of an analytical protocol using positive ion infusion electrospray mass spectrometry (ESI/MS) in conjunction with tandem mass spectrometry which affords both identification and quantification of TAGs in edible oils samples.</p> <p> This thesis reports a simple, comprehensive and quantitative method for the analysis of TAGs in edible oils in which the optimized method involves the infusion of an oil sample in chloroform:methanol (1:1) solution (~10-15 μg/mL of oil) in the presence of 0.5 mM LiCl. A sequence of corrections were applied to the raw peak area data of the TAG molecular ions, [M+Li]+, to account for: (1) normalization of peak area data using three internal standards, (2) peak area contributions of M+2 isotopic peaks of TAGs with one more degree of unsaturation and (3) peak area contributions of LiCl adduct ions, [M+Li+LiCl]+, when applicable. The major correction involved multiplication to a given TAG peak area by the appropriate electrospray relative response factor (RRF) for that TAG. The RRFs for all TAGs containing between 48 and 63 carbons in their fatty acyl chains and between 0 and 9 degrees of unsaturation were extrapolated from experimentally determined response factors of a series of standards. The RRFs were found to decrease by 6.7% for each additional acyl chain carbon but increased by 18.6% for each double bond. Comparison of these calculated RRFs to reported RRFs for a series of TAG standards showed an excellent correlation (1.06% ± 10.20% RSD).</p> <p> The use of Li+ in TAG analysis followed from the reports by Hsu and Turk [93] and Han and Gross [18] which showed that Li+ afforded more intense MS, and particularly MS/MS, spectra than either H+ or Na+. The enhanced intensities in MS/MS spectra (determined using a triple quadrupole mass spectrometer) were critical for the identification of TAGs, including the identity of the fatty acyl group located at the sn-2 position. However, this method cannot distinguish unambiguously between isobaric TAGs. This methodology was applied to the profiling of a number of edible oils including canola, olive, sesame, grape seed, walnut and hemp seed oils. The major TAGS in these samples contained 52, 54 and 56 carbons with between 0 and 11 degrees on unsaturation in a given TAG. There were minor amounts of TAGs containing 50, 55 and 57 carbons.</p> <p> The ability of this method to determine quantitatively the number of degrees of unsaturation in an oil sample was tested by examining a series of partially hydrogenated canola oil samples kindly provided by Bunge Canada. Five oil samples derived from a single feedstock with differing numbers of degrees of unsaturation, measured as iodine values, were subjected to our analytical method. The measured iodine values were compared to iodine values calculated from the number of degrees of unsaturation obtained by our MS-based method. The slope of this correlation was 1.10 with an R^2 = 0.995. Overall, this method is much simpler and more accurate than the protocol described by Han and Gross [18]. This methodology will be applied as routine method for the analysis of TAGs in biological samples such as blood samples.</p> / Thesis / Master of Science (MSc)
65

Void Formation and Mortality During Liquid Composite Molding

Turner, Jared Michael 12 December 2023 (has links) (PDF)
Within the high-performance composite manufacturing industry, there exists a need to improve the reliability of LCM (Liquid Composite Molding) manufacturing processes in producing composite parts that better approach the quality and consistency of pre-impregnated composite tapes that are cured in autoclaves with cost being a driving factor of this need. One obstacle to that end is the phenomenon of void formation during the LCM infusion processes. The formation of these voids through different mechanisms leads to composite parts with lower mechanical properties and consistency than their pre-impregnated autoclave cure counterparts. The objective of this research is to investigate the different mechanisms through which voids form during LCM processes as well as potential actions that can be taken to reduce the total percent volume of voids that form during the infusion. This research also aims to investigate the correlation of the void content observed at the tool-ply interface compared to the void content through the thickness of composite laminates. Finally, this research investigates the effect that chemical modification of the wettability of carbon fiber fabrics has on void formation during infusions.
66

Acid-Base Regulation in the Bullfrog (Rana catesbiana) Following Acid Infusions and Enforced Submergence

Lindinger, Michael 12 1900 (has links)
This study examined the acid-base and ionoregulatory responses by the skin and kidney of adult bullfrogs (Rana catesbiana) during recovery from non-respiratory acidoses. Acidosis was induced by intravascular infusions of HCl (3,000 uequiv/kg), or NH4Cl (4,000 uequiv/kg), or by 45 min enforced submergence. Infused acids were immediately buffered by the extracellular fluids (ECF) and moved rapidly into the intracellular compartment. Clearance of the acid load was slow (> 24 h post-infusion) and only in NH4Cl loaded frogs was the full amount cleared within 5 days. Excess acid was excreted primarily by increased renal NH4+ effluxes. The skin contributed very little to the net acid excretion; instead large "base" losses ("acid" uptake) occurred. Acid infusions also resulted in large ion losses and elevated water uptake across the skin, with electrolytes and water moving down chemical gradients. Frogs infused with HCl died within 96 h; NH4Cl loaded frogs all survived.Forced submergence resulted in a severe lactacidosis which was corrected in 12 h by a combination of renal/cutaneous acid excretion (9:1 ratio) and metabolic utilization of lactate and H+ (~ 95% of excess acid load). Acid excretion occurred primarily as NH4+ efflux by the kidney and skin. A 1:1 exchange of Na+ influx/NH4+, efflux across the skin was found (r = 0.94; P < 0.01) when Jin Na+ was elevated over basal levels (30-40 uequiv/kg·h). Lactate and net acid effluxes by the skin and kidney diminished by 24 h post-disturbance and accounted for 4 to 6% of the total estimated load to the animal. All frogs survived the diving protocol. Restoration of acid-base state in acidotic bullfrogs by ECF and non-ECF mechanisms, as well as the renal and cutaneous responses to the acidosis, is discussed and compared to that of other vertebrates. It is concluded that anurans, and the bullfrog in particular, are poor regulators of acid-base state but instead are very tolerant to marked disturbances of acid-base balance. / Thesis / Master of Science (MS)
67

Characterization of the Vacuum Assisted Resin Transfer Molding Process for Fabrication of Aerospace Composites

Grimsley, Brian William 29 December 2005 (has links)
This work was performed under a cooporative research effort sponsored by the National Aeronautics and Space Administration (NASA) in conjunction with the aerospace industry and acedemia. One of the primary goals of NASA is to improve the safety and affordability of commercial air flight. Part of this goal includes research to reduce fuel consumption by developing lightweight carbon fiber, polymer matrix composites to replace existing metallic airframe structure. In the Twenty-first Aircraft Technology Program (TCAT) efforts were focused on developing novel processing methods to fabricate tailored composite airframe structure. The Vacuum Assisted Resin Transfer Molding (VARTM) processing technique offers a safer, more affordable alternative to manufacture large scale composite fuselages and wing structures. Vacuum assisted resin transfer molding is an infusion process originally developed for manufacturing of composites in the marine industry. The process is a variation of Resin Transfer Molding (RTM), where the rigid matched metal tooling is replaced on one side with a flexible vacuum bag. The entire process, including infusion and consolidation of the part, occurs at atmospheric pressure (101.5 kPa). High-performance composites with fiber volumes in the range of 45% to 50% can be achieved without the use of an autoclave. The main focus of the VARTM process development effort was to determine the feasibility of manufacturing aerospace quality composites with fiber volume fractions approaching 60%. A science-based approach was taken, utilizing finite element process models to characterize and develop a full understanding of the VARTM infusion process as well as the interaction of the constituent materials. Achieving aerospace quality composites requires further development not only of the VARTM process, but also of the matrix resins and fiber preforms. The present work includes an investigation of recently developed epoxy matrix resins, including the characterization of the resin cure kinetics and flow behaviors. Two different fiber preform architectures were characterized to determine the response to compaction under VARTM conditions including a study to determine the effect of thickness on maximum achievable fiber volume fraction. Experiments were also conducted to determine the permeabilities of these preforms under VARTM flow conditions. Both the compaction response and the permeabilities of the preforms were fit to empirical models which can be used as input for future work to simulate VARTM infusion using process models. Actual infusion experiments of these two types preforms were conducted using instrumented tools to determine the pressures and displacements that occur during VARTM infiltration. Flow experiments on glass tooling determined the fill-times and flow front evolution of preform specimens of various thicknesses. The results of these experiments can be used as validation of process model infusion simulations and to verify the compaction and permeability empirical models. Panels were infused with newly developed epoxy resins, cured and sectioned to determine final fiber volume fractions and part quality in an effort to verify both the infusion and compaction experimental data. The preforms characterized were found to have both elastic and inelastic compression response. The maximum fiber volume fraction of the knitted fabrics was dependent on the amount of stacks in the preform specimen. This relationship was found in the determination of the Darcy permeabilities of the preforms. The results of the characterization of the two epoxy resin systems the show that the two resins have similar minimum viscosities but significantly different curing behaviors. Characterization of the VARTM process resulted in different infusion responses in the two preform specimens investigated. The response of the saturated preform to a recompaction after infusion indicated that a significant portion of the fiber volume lost during infusion could be recovered. Fiber volume and void-content analysis of flat composite panels fabricated in VARTM using the characterized resins and preforms resulted in void-free parts with fiber volumes over 58%. Results in the idealized compaction tests indicated fiber volumes as high as 60% were achievable with the knitted fabric. The work over the presented here has led to a more complete understanding of the VARTM process but also led to more questions concerning its feasibility as an aerospace composite manufacturing technique. / Master of Science
68

Analysis of Cyanate Ester Resins and Graphite Fabric for Use in Resin Film Infusion Processing

Myslinski, Paul Joseph 23 December 1997 (has links)
The objective of this investigation was to characterize two cyanate ester resins and a eight harness satin (8HS) graphite fabric for use in resin film infusion (RFI) processing. Two cyanate ester resin systems were characterized to determine their cure-kinetics, and viscosities during cure. A 8HS graphite fabric was tested in compaction and through the thickness permeability. A one-dimensional, through the thickness, flow and cure computer simulation was run. The resin cure-kinetics models predicted the curing behavior of the resins as functions of time, temperature, and degree of cure. The proposed viscosity models determined the resin viscosity as a function of temperature and degree of cure. The 8HS graphite fabric was tested in compaction and through the thickness permeability to determine the effect of compaction pressure on fiber volume fraction and in turn on through the thickness permeability. The one-dimensional RFI flow and cure simulation combined the cure-kinetics and viscosity models of the resins with the characteristics of the graphite fabric and determined resin infiltration and cure times. The proposed cure-kinetics and viscosity models were more than adequate in modeling the cure and flow behavior of the cyanate ester resin systems. Power law curve fits accurately represented the compaction and through the thickness permeability of the 8HS graphite fabric. Finally, the one-dimensional RFI flow and cure simulation showed that resin viscosity was the major influence on the infiltration times. / Master of Science
69

Compaction and Cure of Resin Film Infusion Prepregs

Thompson, Joseph E. 07 January 2005 (has links)
Gutowski et al.'s model has been employed to describe the cure and consolidation of prepregs used for resin film infusion. Resin kinetics, rheology, flow and fiber deformation are considered. Resin kinetics are simulated with an isothermal autocatalytic-1 type relation. The non-Newtonian viscosity of the Cytec&#153; 754 resin is represented with a gel type expression. The one dimensional flow of resin through a deformable, partially saturated porous medium is studied. A nonlinear partial differential equation describing the spatial and temporal variation of the fiber volume fraction combining the continuity equation, Darcy's Law, and mat compressibility has been derived and solved numerically. Resin is assumed to be incompressible and inertial effects are neglected. Based on the resin content of regions where resin and fiber coexist, expressions for tracking resin flow through fully and partially saturated regions of fiber are given. Values of material parameters for the E-QX 3600-5 glass fabric are estimated from literature data involving compression of similar dry fabrics and through comparison of computed results with the experimental data. Results for the final thickness of the consolidated part agree with the experimental values, but those for the mass loss do not. / Master of Science
70

"Interações entre modelado e solo no transecto Espraiado, São Pedro, SP" / Soil-landform relationships in the Espraiado Transect, São Pedro, São Paulo.

Furquim, Sheila Aparecida Correia 24 April 2002 (has links)
O objetivo da presente pesquisa consiste em identificar feições macro e micromorfológicas (em escala de campo e do microscópio óptico, respectivamente) e evidências analíticas (parâmetros físicos e químicos) que indiquem possíveis mecanismos de translocações, perdas e acumulações de matéria no interior da cobertura pedológica, possivelmente responsáveis pela modificação do modelado em um transecto localizado na região de São Pedro (SP). O transecto estudado, denominado Espraiado, subdivide-se em 5 segmentos: segmento superior, segmento médio e segmentos inferiores a, b e c. O segmento superior apresenta baixas declividades e presença do Neossolo Quarzarênico, solo espesso e arenoso caracterizado pela sequência vertical de horizontes A, AE, E com bandas e C-1. O segmento médio apresenta declividades comparativamente médias e presença dos Argissolos Amarelo e Acinzentado, caracterizados pela espessura menor que a do Neossolo Quartzarênico e pela sequência de horizontes A, AE, E com bandas, Bt, C-2 e C-3. Os segmentos inferiores possuem as maiores declividades e solos com a maior presença de argila e a menor espessura do transecto: Cambissolo Háplico, com sequência de horizontes A, ABi, Bi, C-2 e C-3; e Neossolo Litólico, com sequência de horizontes A, C-2 e C-3. As feições identificadas, principalmente macro e micromorfológicas, indicam a ocorrência de processos químicos e mecânicos no interior da cobertura pedológica, desencadeados principalmente pela circulação da água no interior dos solos e responsáveis pela redistribuição e/ou remoção de material em todo o transecto. No Neossolo Quartzarênico, onde há provavelmente maior infiltração de água e dominância do fluxo interno vertical, foi encontrada maior presença das seguintes feições: bandas e interbandas, interpretadas como evidências de-iluviação de plasma; golfos nas partículas de quartzo, interpretados como evidências de dissolução de sílica; e feições relacionadas ao fenômeno de plasma infusion, o qual provoca a desintegração das partículas de areia em partículas menores. Nos Argissolos (Amarelo e Acinzentado) e no Cambissolo Háplico, onde há menor infiltração de água e provavelmente maior presença de fluxo interno lateral, estas feições aparecem em menor quantidade, mas dominam outras, tais como: bandas e interbandas, provavelmente associadas à perda de de plasma do horizonte subjacente; oríficos e concavidades superficiais provavelmente associados ao processo de piping, mosqueamentos que indicam processos de hidromorfia e, portanto, maior mobilidade do ferro reduzido, e feições relacionadas à mobilização de plasma e esqueleto nos macroporos. As únicas feições encontradas que indicam a deposição ou precipitação de elementos no sistema foram as bandas do Neossolo Quartzarênico (as quais indicam simultaneamente perda de matéria), e as denominadas “superfícies duplas" das partículas de quartzo. Desta forma, parece que a cobertura pedológica do transecto Espraiado caracteriza-se principalmente pela perda generalizada de matéria, provavelmente associada a uma perda de volume dos solos e a um rebaixamento do modelado local, assim como descrito em outras áreas tropicais. Assim, os resultados apresentados estão em desacordo com a idéia de oposição entre os processos pedogenéticos e morfogenéticos, comumente presente na visão tradicional das relações solo-relevo, uma vez que os processos deduzidos são possivelmente responsáveis não apenas por mudanças de características morfológicas da cobertura pedológica, mas também por mudanças no modelado. Além disto, a presença destes processos na área estudada parece estar de acordo com os princípios da teoria de etchplanação. / The objective of this research is to identify macro and micromorphological features (field and and optical microscopic scale, respectively) and analitycal evidences (physical and chemical parameters), indicative of translocations, losses and acumulations mechanisms inside the soils, that probably leads to changes in the form of a transect, localized in São Pedro region, São Paulo State, Brazil. The studied transect, called Espraiado, is divided into five segments: superior segment, medium segment and a, b and c inferior segments. The superior segment presents low slope angles and presence of quartz sand, that is a deep soil characterized of the vertical sequence of A, AE, E (with bands) and C-1 horizons. The medium segment has moderate slope angles and the presence of podzolic soils, that are shallower than quartz sand soil and follow vertical sequence of horizons: A, AE, E (with bands), Bt, C-2 and C-3. The inferior segments have the highest slope angles and soils with the highest clay content and the lowest thickness of the transect: cambic soil, that has vertical sequence of A, ABi, Bi, C-2 and C-3 horizons; or A, C-2 and C-3 horizons. The identified macro and micromorphological features suggest the occurrence of chemical and mechanical processes inside the pedological cover, mainly triggered for water circulation in soils. These processes are probably responsible for material translocation and/or remotion in the whole transect. In quartz sand soil, where there are probably high water infiltration rates and dominant internal vertical flux, there are the great amounts of the follow features: bands/interband, interpreted as plasma e-illuviation evidences, embayed quartz particles, interpreted as silica dissolution evidences, and plasma infusion, a phenomenon that leads to the desintegration of sand-sized particles and the formation of silt-sized particles. In podzolic and cambic soils ,where there are probably lower water infiltration rates soils and dominant internal lateral flux, there are fewer of these features and dominance of others, like bands/interbands probably related to plasma losses; holes and concavities probably related to piping processes, motlles suggesting hydromorfic processes that induce the mobility of reduced Fe, and features associated to plasma and skeleton mobility in macropores. Only two features suggest deposition or precipitation of elements in the soil system: bands, mainly in quartz sand soil, and the “double surfaces" of the quartz particles. It seems that pedological cover of the Espraiado transect is mainly characterized by general losses that lead to soil volume loss and landsurface lowering, as described in other tropical areas. Therefore, the presented results disagree with the opposition idea of pedogenetic and morphogenetic processes, presented in traditional views of soil-landforms relationships, since the deduced processes in this research are probably responsible for both soil and landform changes. Furthermore, the presence of the identified chemical processes in Espraiado transect appear to conform to concepts of etchplanation.

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