Shallow foundations rested on Leda clay that are widely distributed in Eastern Canada exhibit shrinkage characteristics and are prone to differential settlements. Due to this reason, significant repairs are necessary to the foundations and basements of residential structures constructed in Leda clay deposits. Differential settlements are commonly attributed to the changes in the natural water content of soils associated with water infiltration, evaporation or plant transpiration (i.e., tree-roots-suction). Various research studies have been undertaken to estimate the possible settlements of shallow foundations associated with the water infiltration or evaporation. Several thumb rules have been proposed through research studies, providing recommendations with respect to the distance at which trees must be planted as a function of their heights at maturity such that differential settlements can be avoided. However, limited studies have been carried out to estimate or model the settlements of shallow foundations taking into account the influence of tree-roots-suction. In the present research program, a comprehensive experimental study regarding the deformation characteristics of a sandy loam soil from Ottawa due to tree-root-suction is undertaken, using specially designed equipment. The study has been undertaken using a sandy loam soil so that the testing program can be conducted in a shorter period of time. An artificial rooting system (ARS) was designed and placed in a specially designed tank at the University of Ottawa to simulate tree-roots-suction and measure soil surface settlements associated with a decrease in natural water content (or increase in soil suction) using particle image velocimetry (PIV) technique. The ARS consists of an artificial root, suction generator, matric suction and volumetric water content monitoring devices. The variation of matric suction and volumetric water content are monitored at various depths using the instrumentation of the ARS. Based on the results of the experimental studies, a methodology is proposed to model the settlement behaviour of sandy loam soils due to suction from ARS, using commercial finite element software, SEEP/W and SIGMA/W (i.e. software package of GeoStudio 2007). The study offers a reasonably good comparison between the measured surface settlements and those estimated using the finite element modelling analysis. The modelling methodology presented in this thesis is promising and may be extended for estimating the settlement behaviour associated with the tree roots suction of Leda clay deposits and to other soils.

This research has investigated the effect of tyre rutting of wheeled construction plant performance traversing in wet and deformable terrain, specifically clay and sand. The purpose was to translate the wheel rutting into performance reduction measured in drawbar-pull. The ultimate goal was to translate the power loss into practical effects on cost, time and other economic variations on construction projects that are characterised by movement of wheeled plant on long haulage deformable roads. In order to achieve this aim, mathematical modelling was deployed based on Newton’s laws of motion, principles of energy conservation and numerical integration. The model is based on a single rigid wheel because construction plant tyres are inflated to high pressure in order to support heavy loads thereby translating the flexible tyres into rigid mode. The results from the mathematical model were verified using a three stage robust verification process which included computational analysis based on two existing semi-empirical methods and real experimental data. Laboratory experiments using Mobility SF- 3713 were also used to check the validity of the results. The results from the mathematical model verify that a flexible tyre can operate in rigid mode if it encounters softer and wet ground. Results further indicate that the soil cohesion, angle of shearing resistance and moisture content play key roles in the subsequent power loss created by motion resistance. All the results from computational analysis and the experiments were found to be consistent with the mathematical model results. The study concludes that there is ample evidence to suggest that there is significant power loss associated with wheeled construction plant traversing in soft terrain which can be assessed. The study further concludes that a combination of economic decisions on variables must be considered with respect to existing ground conditions. This will considerably reduce uncertainty levels in cost and resource management on construction projects.

Esta dissertação apresentou um estudo dos mecanismos de transporte de sódio, fosfato e amônio em colunas indeformadas de material inconsolidado residual de arenitos da Formação Adamantina. Em campo foi realizada caracterização táctil visual do material, alem de ensaios de condutividade hidráulica. Em laboratório, realizou-se ensaio de coluna em material indeformado, para que fossem obtidos os parâmetros de fluxo de água: velocidade linear media, velocidade de Darcy, vazão e condutividade hidráulica. Também foram obtidos os coeficientes de dispersão hidrodinâmica dos três íons estudados por meio de quatro métodos. Os fatores de retardamento dos íons foram obtidos por meio de três métodos. Para auxiliar nas analises, o solo foi caracterizado mineralógica, química, física e físico-quimicamente. Adicionalmente foram feitas analises da poro simetria e estudo das trajetórias de transporte. As informações foram integradas para que fosse possível analisar os parâmetros de transporte de solutos no solo. Com esta pesquisa percebeu-se que o uso dos parâmetros de transporte em modelagem do transporte de contaminantes deve ser feito com cautela, observando tanto as características do solo (mineralógicas, físicas, físico-químicas) quanto os modelos conceituais e as limitações dos métodos utilizados. / This research aimed to study the transport mechanisms of sodium, phosphate and ammonium in undisturbed columns of unconsolidated residual material of the sandstones from the Adamantina Formation. At field, visual and tactile characterization of the material were performed as well as hydraulic conductivity tests . At laboratory, there were made column tests in undisturbed samples to obtain the parameters of water flow, i.e., average linear velocity, Darcy velocity, flow rate and hydraulic conductivity. Hydrodynamic dispersion coefficients of every studied ion were determined using four methods. The retardation factors of the three ions were obtained using three methods. To assist the analysis, the soil was mineralogical, chemistry, physically and physic-chemically characterized. We also analyzed the water retention curve, mercury intrusion porosimetry and solute transport trajectories. All available data were integrated for analyzing the parameters of solute transport in soil. The results showed that the use of transport parameters in modeling of contaminant transport should be done with caution, observing soil characteristics, the conceptual models and the limitations of the methods used.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-03-07T13:12:05Z No. of bitstreams: 1 Luciana Maria Herculano da Silva.pdf: 1397632 bytes, checksum: cca869a58fb4ebdc78f6d4d8be57f51f (MD5) / Made available in DSpace on 2017-03-07T13:12:06Z (GMT). No. of bitstreams: 1 Luciana Maria Herculano da Silva.pdf: 1397632 bytes, checksum: cca869a58fb4ebdc78f6d4d8be57f51f (MD5) Previous issue date: 2016-07-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The evaluation of soil quality is an important tool to monitor their degradation and to sustainable practices implementation, by indicators that can relate to soil quality with agricultural activity. The Caatinga, an exclusively Brazilian biome, has a high degradation rate, resulting of human action in inadequate soil management. The objective was to evaluate changes of chemical and biological indicators of organic matter due to the seasonality in preserved and disturbed areas of Caatinga ecoregions in Pernambuco, as well as qualitative characteristics of soil organic matter in these environments and uses. Three areas were selected: one in Buíque and two in Serra Talhada, in each area were studied two conditions of land use (soil in areas with preserved Caatinga coverage and areas with agricultural use).Soil samples were collected between September/2014 and September/2015, covering dry and rainy seasons in semiarid region. In each use and area, there were collected three composite soil samples at layers 0-5, 5-10 and 10-20 cm. Analysis to chemical and physical soil characterization were carried out in addition to biological analysis of total organic carbon (TOC), labile fractions of oxidizable carbon (LFCO), microbial biomass carbon (MBC), basal soil respiration (BSR), microbial quotient (qMIC), physical fractionation of organic matter (POM), physical fractionation of organic matter associated with mineral (MOM) and chemical fractionation of humic substances (HS).Data were analyzed by T test, at 5% probability. It was observed that all relevant variables are influenced by seasonality, and soil texture to LFCO, MBC and TOC, indicating a greater influence on labile carbon fractions.While the characterization by FTIR set directly related to carbon in MOP fractions with AH and AF, and MOM with humin. / A avaliação da qualidade do solo é uma ferramenta importante para monitorar a sua degradação bem como planejar a implantação de práticas sustentáveis, verificada por indicadores que podem relacionar a qualidade do solo com atividade agrícola deste. A Caatinga, um bioma exclusivamente brasileiro, tem um alto índice de degradação, resultado da ação antrópica de manejo inadequado do solo. O objetivo da pesquisa foi de avaliar as alterações dos indicadores químicos e biológicos da matéria orgânica em função da sazonalidade, em áreas preservadas e antropizadas de ecorregiões da Caatinga em Pernambuco, bem como características qualitativas da matéria orgânica do solo nesses ambientes e usos. Para tanto, foram selecionadas três áreas: uma em Buíque e duas em Serra Talhada, em cada área foram estudadas duas condições de uso do solo (solos em áreas com cobertura de Caatinga preservada e áreas com uso agrícola). As coletas foram realizadas entre setembro/2014 e setembro/2015, abrangendo a estações seca e chuvosa dessas áreas no semiárido. Em cada uso, por área, foram coletadas três amostras compostas de solo nas camadas de 0-5, 5-10 e 10-20 cm. Foram realizadas análises de caracterização química e física dos solos, além das análises biológicas de carbono orgânico total (COT), frações lábeis de carbono oxidáveis (FLCO), carbono da biomassa microbiana (CBM), respiração basal do solo (RBS), quociente microbiano (qMIC), fracionamento físico da matéria orgânico (MOP), fracionamento físico da matéria orgânica associada aos minerais (MOM) e fracionamento químico das substâncias húmicas (SH). Os dados foram analisados pelo teste T, ao nível de 5% de probabilidade. Observou-se que todas as variáveis obtidas são influenciadas pela sazonalidade e pela textura do solo para FLCO, CBM e COT, indicando maior influência sobre as frações de carbono lábeis. Enquanto a caracterização por FTIR define relação direta com carbono nas frações de MOP com AH e AF, e MOM com humina.

abstract: Aboveground net primary production (ANPP) is an important ecosystem process that, in drylands, is most frequently limited by water availability. Water availability for plants is in part controlled by the water holding capacity of soils. Available water holding capacity (AWHC) of soils is strongly influenced by soil texture and depth. This study drew upon localized rain gauge data and four data-sets of cover-line and biomass data to estimate ANPP and to determine annual precipitation (PPT). I measured soil depth to caliche and texture by layer of 112 plots across the four landscape units for which estimation of ANPP were available. A pedotransfer function was used to estimate AWHC from soil depth increments to depth of caliche measurements and texture analysis. These data were analyzed using simple and multivariate regression to test the effect of annual precipitation and available water holding capacity on aboveground net primary production. Soil texture remained constant among all plots (sandy loam) and depth to caliche varied from 15.16 cm to 189 cm. AWHC and the interaction term (PPT*AWHC) were insignificant (p=0.142, p=0.838) and annual PPT accounted for 18.4% of the variation in ANPP. The y-intercept was significantly different for ANPP ~ annual PPT when considering AWHC values either above or below 3 cm. Shrub ANPP was insensitive to precipitation regardless of AWHC (R2=-0.012, R2=0.014). Results from this study indicate that a model incorporating annual PPT and AWHC may not serve as a good predictor for ANPP at a site level where there is little variation in soil texture. / Dissertation/Thesis / Masters Thesis Sustainability 2019

<p>U&nbsp; radu&nbsp; je&nbsp; analizirana&nbsp; flora&nbsp; i&nbsp; vegetacija&nbsp; Deliblatske pe&scaron;čare. Cilj istraživanja bio je utvrđivanje&nbsp; recentnog stanja&nbsp; i&nbsp; osnovnih&nbsp; karakteristika&nbsp; flore&nbsp; Deliblatske pe&scaron;čare,&nbsp; ali&nbsp; i&nbsp; analiza&nbsp; dinamike&nbsp; flore&nbsp; Deliblatske pe&scaron;čare u poslednjih 220 godina. Jedan od ciljeva je bila analiza sukcesivnih promena u flori i vegetaciji Deliblatske&nbsp; pe&scaron;čare&nbsp; i&nbsp; predikcija&nbsp; njihovog&nbsp; pravca&nbsp; i kvaliteta,&nbsp; kao&nbsp; i&nbsp; utvrđivanje&nbsp; diverziteta&nbsp; i sintaksonomske &scaron;eme vegetacije Deliblatske pe&scaron;čare uz klasifikaciju problematičnih vegetacijskih grupa u &scaron;irem aspektu- na nivou čitave Srbije, ali i Pontskog i Panonskog regiona. Terenska istraživanja su vr&scaron;ena u periodu&nbsp; 2012-2018&nbsp; godine.&nbsp; Floristički&nbsp; podaci&nbsp; su uzimani&nbsp; na&nbsp; istim&nbsp; lokalitetima&nbsp; kao&nbsp; i&nbsp; fitocenolo&scaron;ki snimci.&nbsp; Ukupno&nbsp; je&nbsp; uzeto&nbsp; 282&nbsp; fitocenolo&scaron;ka&nbsp; snimka metodom po Braun-Blankeu. Za florističku analizu je<br />obrađena&nbsp; 301&nbsp; referenca,&nbsp; a&nbsp; na&nbsp; terenu&nbsp; su&nbsp; prikupljeni podaci&nbsp; za&nbsp; 440&nbsp; vrsta,&nbsp; od&nbsp; kojih&nbsp; je&nbsp; 6&nbsp; po&nbsp; prvi&nbsp; put registrovano na ovom području. U florističku analizu je uključeno&nbsp; ukupno prikupljenih&nbsp; 9.887&nbsp; podataka. U radu je dat floristički pregled u vidu spiska taksona koji&nbsp; su&nbsp; zabeleženi&nbsp; na&nbsp; Deliblatskoj&nbsp; pe&scaron;čari&nbsp; (ima&nbsp; ih 1072),&nbsp; sa&nbsp; lokalitetima&nbsp; na&nbsp; kojima&nbsp; su&nbsp; do&nbsp; sada pronađeni,&nbsp; obeleženi&nbsp; su&nbsp; prvi&nbsp; nalazi&nbsp; za&nbsp; vrste&nbsp; i<br />podvrste, a obeležene su i vrste koje su potvrđene na terenskim&nbsp; istraživanjima&nbsp; u&nbsp; okviru&nbsp; ove&nbsp; disertacije. Floristička&nbsp; analiza&nbsp; je&nbsp; realizovana&nbsp; klasičnim numeričkim&nbsp; metodama,&nbsp; u&nbsp; cilju&nbsp; prezentacije najzastupljenijih&nbsp; familija,&nbsp; rodova,&nbsp; životnih&nbsp; formi&nbsp; i<br />horotipova.&nbsp; Predstavljene&nbsp; su&nbsp; endemične,&nbsp; reliktne&nbsp; i ugrožene&nbsp; i&nbsp; ivnazivne&nbsp; vrste&nbsp; Pe&scaron;čare.&nbsp; Na&nbsp; Deliblatskoj pe&scaron;čari je zabeleženo 16 endemskih, 22 reliktnih, 49 strogo&nbsp; za&scaron;tićenih,&nbsp; 8&nbsp; iz&nbsp; Crvenje&nbsp; knjige&nbsp; flore&nbsp; Srbije&nbsp; i 54&nbsp; invazivna&nbsp; taksona.&nbsp; Dinamika&nbsp; florističkih istraživanja&nbsp; je&nbsp; predstavljena&nbsp; analizom&nbsp;&nbsp; literaturnih podataka i dinamike istraživanja ovog područja, a u skladu&nbsp; sa&nbsp; značajnim&nbsp; dru&scaron;tvenim&nbsp; promenama područja,&nbsp; od&nbsp; kojih&nbsp; se&nbsp; kao&nbsp; najznačajniji&nbsp; momenat izdvaja&nbsp; početak&nbsp; po&scaron;umljavanja&nbsp; Pe&scaron;čare.&nbsp; U&nbsp; pregledu vegetacije&nbsp; Deliblatske&nbsp; pe&scaron;čare&nbsp; su&nbsp; predstavljeni najznačajniji vegetacijski tipovi ovog područja, date su&nbsp; fitocenolo&scaron;ke&nbsp; tabele&nbsp; snimaka&nbsp; koji&nbsp; su&nbsp; za&nbsp; ove zajednice&nbsp; uzeti&nbsp; u&nbsp; toku&nbsp; terenskog&nbsp; istraživanja, fotografije zajednica i mape sa tačkama na kojima su uzimani&nbsp; snimci.&nbsp; U&nbsp; okviru&nbsp; pregleda&nbsp; vegetacije Deliblatske pe&scaron;čare, pored već poznatih vegetacijskih jedinica,&nbsp; po&nbsp; prvi&nbsp; put&nbsp; su&nbsp; predstavljene&nbsp; tri&nbsp; asocijacije autohtone&nbsp; vegetacije&nbsp; i&nbsp; dve&nbsp; sastojine&nbsp; antropogenih zajednica.&nbsp; U&nbsp; cilju&nbsp; razre&scaron;avanja&nbsp; problematike klasifikacije&nbsp; pe&scaron;čarske&nbsp; vegetacije,&nbsp; prikupljeni&nbsp; su&nbsp; i<br />analizirani fitocenolo&scaron;ki podaci za čitavu Srbiju, ali i ceo&nbsp; Panonski&nbsp; i&nbsp; Pontski&nbsp; basen.&nbsp; Na&nbsp; ovaj&nbsp; način&nbsp; je detaljno&nbsp; razja&scaron;njena&nbsp; klasifikacija&nbsp; psamofitskih zajednica&nbsp; Deliblatske&nbsp; pe&scaron;čare&nbsp; do&nbsp; nivoa subasocijacija. Dinamika&nbsp; vegetacije&nbsp; Deliblatske&nbsp; pe&scaron;čare&nbsp; je analizirana&nbsp; praćenjem&nbsp; sukcesivnih&nbsp; stadijuma obrastanja&nbsp; peska&nbsp; i&nbsp; zatvaranjem&nbsp; sklopa&nbsp; sastojina. Monitoring je podrazumevao i pedolo&scaron;ke analize na<br />na&nbsp; lokalitetima&nbsp; različitih&nbsp; vegetacijskih&nbsp; tipova.&nbsp; U okviru&nbsp; praćenja&nbsp; dinamike&nbsp; vegetacije,&nbsp; realizovana&nbsp; su istraživanja&nbsp; na&nbsp; područjima&nbsp; na&nbsp; kojima&nbsp; se&nbsp; vr&scaron;i revitalizacija stepskih sastojina. Rezultati ukazuju da je&nbsp; su&nbsp; revitalizacijom&nbsp; postignuti&nbsp; dobri&nbsp; rezultati&nbsp; koje treba&nbsp; dalje&nbsp; usmeravati&nbsp; i&nbsp; korigovati&nbsp; u&nbsp; pravcu postizanja&nbsp; optimalnih&nbsp; uslova&nbsp; za&nbsp; opstanak&nbsp; i&nbsp; razvoj stepske, ali i drugih tipova vegetacije.<br />Rezultati&nbsp; ove&nbsp; doktorske&nbsp; disertacije&nbsp; daju&nbsp; dobru osnovu za dalja floristička i vegetacijska istraživanja Deliblatske&nbsp; pe&scaron;čare,&nbsp; ali&nbsp; i&nbsp; drugih,&nbsp; sličnih,&nbsp; prirodnih<br />područja&nbsp; i&nbsp; značajan&nbsp; doprinos&nbsp; proučavanju&nbsp; flore&nbsp; i vegetacije Srbije.</p> / <p>In this research was analyzed flora and vegetation of the&nbsp; Deliblato&nbsp; Sands.&nbsp; The&nbsp; aim&nbsp; of&nbsp; the&nbsp; study&nbsp; was&nbsp; to determine the recent state and basic characteristics of the flora of Deliblato Sands, as well as to analyze the dynamics&nbsp; of&nbsp; flora&nbsp; in&nbsp; the&nbsp; last&nbsp; 220&nbsp; years.&nbsp; One&nbsp; of&nbsp; the aims&nbsp; was&nbsp; to&nbsp; analyze&nbsp; the&nbsp; successive&nbsp; changes&nbsp; in&nbsp; the flora&nbsp; and&nbsp; vegetation&nbsp; of&nbsp; Deliblato&nbsp; Sands&nbsp; and&nbsp; the prediction of their direction and&nbsp; quality. Also, one of the&nbsp; goals&nbsp; was&nbsp; to&nbsp; determine&nbsp; the&nbsp; diversity&nbsp; and syntaxonomical&nbsp; scheme&nbsp; of&nbsp; vegetation&nbsp; through classification&nbsp; of problematic vegetation groups in the wider&nbsp; aspect&nbsp; -&nbsp; at&nbsp; the&nbsp; level&nbsp; of&nbsp; the&nbsp; whole&nbsp; Serbia,&nbsp; but also of Pontic and Pannonian region. Field&nbsp; research were&nbsp; carried&nbsp; out&nbsp; in&nbsp; the&nbsp; period&nbsp; 2012-2018.&nbsp; Floristic data were taken at the same sites as phytocenological plots.&nbsp; In&nbsp; total,&nbsp; 282&nbsp; phytosociological&nbsp; relev&eacute;s&nbsp; were taken&nbsp; using&nbsp; the&nbsp; Braun-Blanquet&nbsp; method.&nbsp; 301 different&nbsp; references&nbsp; were&nbsp; processed&nbsp; for&nbsp; floristic analysis&nbsp; and&nbsp; data&nbsp; for&nbsp; 440&nbsp;&nbsp; species&nbsp; were&nbsp; collected&nbsp; in the field&nbsp; (6 of them&nbsp; were registered for the first time in&nbsp; this&nbsp; area).&nbsp; A&nbsp; total&nbsp; of&nbsp; 9,887&nbsp; data&nbsp; collected&nbsp; were included in the floristic analysis. The&nbsp; research&nbsp; gives a&nbsp; floristic&nbsp; overview&nbsp; in&nbsp; the&nbsp; form&nbsp; of&nbsp; a&nbsp; list&nbsp; of&nbsp; taxa recorded&nbsp; in&nbsp; Deliblato&nbsp; Sandst&nbsp; (there&nbsp; are&nbsp; 1072&nbsp; taxa), with the localities where they have been&nbsp; found so far, and&nbsp; the first findings for species and subspecies are marked, as well as the&nbsp; species confirmed in the field research&nbsp; within&nbsp; this&nbsp; dissertation.&nbsp; Floristic&nbsp; analysis was performed using classical numerical methods, in order&nbsp; to&nbsp; present&nbsp; the&nbsp; most&nbsp; represented&nbsp; families, genera,&nbsp; life&nbsp; forms&nbsp; and&nbsp; chorotypes.&nbsp; Endemic,&nbsp; relict and&nbsp; endangered&nbsp; and&nbsp; invasive&nbsp; species&nbsp; of&nbsp; Sandstone are&nbsp; presented.&nbsp; 16&nbsp; endemic,&nbsp; 22&nbsp; relicts,&nbsp; 49&nbsp; strictly protected, 8 from the Red Data Book of Serbian flora and 54 invasive taxa have been recorded in Deliblato Sands.&nbsp; The&nbsp; dynamics&nbsp; of&nbsp; floristic&nbsp; research&nbsp; is represented&nbsp; by&nbsp; the&nbsp; analysis&nbsp; of&nbsp; literary&nbsp; data&nbsp; and&nbsp; the dynamics&nbsp; of&nbsp; research&nbsp; activities&nbsp; in&nbsp; this&nbsp; area.&nbsp; In accordance with the significant social changes of the area,&nbsp; it&nbsp; is&nbsp; noted&nbsp; that&nbsp; the&nbsp; most&nbsp; significant&nbsp; event&nbsp; was the&nbsp; beginning&nbsp; of&nbsp; afforestation&nbsp; of&nbsp; the&nbsp; Sand.&nbsp; The vegetation&nbsp; overview&nbsp; of the Deliblato&nbsp; Sands presents the&nbsp; most&nbsp; significant&nbsp; vegetation&nbsp; types&nbsp; of&nbsp; the&nbsp; area, provides&nbsp; phytosociological&nbsp; tables&nbsp; of&nbsp; relev&eacute;s&nbsp; takenduring&nbsp; this&nbsp; research,&nbsp; photographs&nbsp; of&nbsp; communities and&nbsp; maps&nbsp; with&nbsp; points&nbsp; where&nbsp; the&nbsp; recordings&nbsp; were taken.&nbsp; In&nbsp; addition&nbsp; to&nbsp; the&nbsp; already&nbsp; known&nbsp; vegetation units,&nbsp; within&nbsp; the&nbsp; vegetation&nbsp; review&nbsp; of&nbsp; the&nbsp; Deliblat Sandstone,&nbsp; three&nbsp; associations&nbsp; of&nbsp; indigenous vegetation&nbsp; and&nbsp; two&nbsp; stands&nbsp; of&nbsp; anthropogenic communities&nbsp; were&nbsp; presented&nbsp; for&nbsp; the&nbsp; first&nbsp; time.&nbsp; In order to solve the problem of classification of sandy vegetation, phytocenological data were collected and analyzed for the whole Republic of Serbia, as well as the&nbsp; entire&nbsp; Pannonian&nbsp; and&nbsp; Pontic&nbsp; basin.&nbsp; In&nbsp; this&nbsp; way, the classification of the psammophytic&nbsp; communities of&nbsp; the&nbsp; Deliblato&nbsp; Sands&nbsp; to&nbsp; the&nbsp; level&nbsp; of&nbsp; subassociations was clarified. The vegetation dynamics of the Deliblato Sands were analyzed&nbsp; by&nbsp; monitoring&nbsp; successive&nbsp; stages&nbsp; of&nbsp; sand and&nbsp; steppe&nbsp; vegetation.&nbsp; Monitoring&nbsp; also&nbsp; included pedological&nbsp; analyzes&nbsp; at&nbsp; sites&nbsp; of&nbsp; different&nbsp; vegetation types.&nbsp; As&nbsp; part&nbsp; of&nbsp; the&nbsp; monitoring&nbsp; of&nbsp; vegetation dynamics,&nbsp; research&nbsp; has&nbsp; been&nbsp; carried&nbsp; out&nbsp; in&nbsp; areas where steppe stands are being revitalized. The results indicate&nbsp; that&nbsp; the&nbsp; revitalization&nbsp; has&nbsp; achieved&nbsp; good results that need to be further directed and corrected in&nbsp; order&nbsp; to&nbsp; achieve&nbsp; optimal&nbsp; conditions&nbsp; for&nbsp; the survival&nbsp; and&nbsp; development&nbsp; of&nbsp; steppe&nbsp; and&nbsp; other vegetation types. The&nbsp; results&nbsp; of&nbsp; this&nbsp; doctoral&nbsp; dissertation&nbsp; provide&nbsp; a good&nbsp; basis&nbsp; for&nbsp; further&nbsp; floristic&nbsp; and&nbsp; vegetation research&nbsp; in&nbsp; the&nbsp; Deliblato&nbsp; sands,&nbsp; as&nbsp; well&nbsp; as&nbsp; other similar natural areas and a significant contribution to the study of the flora and vegetation of Serbia.</p>

Shallow foundations rested on Leda clay that are widely distributed in Eastern Canada exhibit shrinkage characteristics and are prone to differential settlements. Due to this reason, significant repairs are necessary to the foundations and basements of residential structures constructed in Leda clay deposits. Differential settlements are commonly attributed to the changes in the natural water content of soils associated with water infiltration, evaporation or plant transpiration (i.e., tree-roots-suction). Various research studies have been undertaken to estimate the possible settlements of shallow foundations associated with the water infiltration or evaporation. Several thumb rules have been proposed through research studies, providing recommendations with respect to the distance at which trees must be planted as a function of their heights at maturity such that differential settlements can be avoided. However, limited studies have been carried out to estimate or model the settlements of shallow foundations taking into account the influence of tree-roots-suction. In the present research program, a comprehensive experimental study regarding the deformation characteristics of a sandy loam soil from Ottawa due to tree-root-suction is undertaken, using specially designed equipment. The study has been undertaken using a sandy loam soil so that the testing program can be conducted in a shorter period of time. An artificial rooting system (ARS) was designed and placed in a specially designed tank at the University of Ottawa to simulate tree-roots-suction and measure soil surface settlements associated with a decrease in natural water content (or increase in soil suction) using particle image velocimetry (PIV) technique. The ARS consists of an artificial root, suction generator, matric suction and volumetric water content monitoring devices. The variation of matric suction and volumetric water content are monitored at various depths using the instrumentation of the ARS. Based on the results of the experimental studies, a methodology is proposed to model the settlement behaviour of sandy loam soils due to suction from ARS, using commercial finite element software, SEEP/W and SIGMA/W (i.e. software package of GeoStudio 2007). The study offers a reasonably good comparison between the measured surface settlements and those estimated using the finite element modelling analysis. The modelling methodology presented in this thesis is promising and may be extended for estimating the settlement behaviour associated with the tree roots suction of Leda clay deposits and to other soils.

In this master work the influence of calcium ions on the cadmium mobility in the sandy and clay soils was investigated. Work subject - samples of Orthieutric Fluvisol and Calcaric-Endohypogleyic Luvisol topsoils taken from arable lands in Balbieriskis distirict. Work objective - to investigate the influence of calcium ions on the cadmium adsorption-desorption processes in the model systems of different kind of soil-Cd(NO3)2-Ca(NO3)2 simulating pH, Cd2+ and Ca2+ amounts. Work methods - the investigated soil samples were agitated for 1 hour with Cd(NO3)2 and Ca(NO3)2 solutions of various concentrations. The solutions were made in the 0.03M NaNO3 for the constant ionic strength maintaining. The Cd amounts in the equilibrium solution after the adsorption were determined with atomic absorption spectrometer (AAS). The Cd desorption was investigated in the samples after adsorption using 0.05M NH4-EDTA (pH 7) solution as extractant. The Cd amount in extract was determined with AAS. Work results - results of the research showed that in the clay soil were accumulated more mobile Cd ions under the influence of Ca ions than in the sandy soil. The clay soil adsorbed for 25 % less and desorbed for 77 % more mobile Cd ions than sandy soil. When soil contamination with Cd was increased from 8 till 40 mg/kg, the Cd adsorption increased about 17 % in both alkaline (pH 8) and acidic (pH 4) medium, while in the sandy soil it decreased about 7 % at pH 8 and increased about 3 % at pH 4. The... [to full text]

Magistro darbe tiriama kadmio ir švino adsorbcijos ir desorbcijos procesai bei jų tarpusavio sąveika skirtingos granuliometrinės sudėties dirvožemiuose. Darbo objektas - du skirtingos granuliometrinės sudėties (priesmėlio ir priemolio) dirvožemiai. Darbo tikslas – ištirti kadmio ir švino adsorbcijos-desorbcijos procesus ir jų tarpusavio sąveikos poveikį jų judrumui tiriamuose dirvožemiuose. Darbo metodai – švino, kadmio, ir jų mišinių adsorbcijos dirvožemiuose procesui tirti dirvožemių ėminiai iki pusiausvyrosios būsenos buvo plakami su skirtingos koncentracijos (0, 0,25, 0,5, 1 mM) Cd (NO3)2, Pb(NO3)2 ir jų mišinių tirpalais, paruoštais 0,03M NaNO3 tirpale pastoviai joninei jėgai palaikyti. Po adsorbcijos eksperimento Cd2+ ir Pb2+ jonų koncentracijos pusiausvirajame tirpale nustatytos liepsnos atominės absorbcinės spektrometrijos metodu (AAS). Desorbcijos procesas ištirtas tuose pačiuose mėginiuose panaudojant ekstrakciją su 0,05M NH4 – EDTA (pH 7) ekstrahentu. Ekstraktuose Pb2+ ir Cd2+ jonų koncentracijos nustatytos liepsnos AAS metodu. Tyrimo rezultatai įvertinti matematiniais-statistiniais metodais naudojant Excel programą. Darbo rezultatai. Atlikus tyrimus nustatyta kad priesmėlio dirvožemis adsorbuoja (esant 1 mM (207 mg•kg-1) koncentracijai) 206,2 mg•kg-1 Pb, 109,9 mg•kg-1 Cd sausosios masės, o desorbuoja 97,7 mg•kg-1 Pb ir 61,6 mg•kg-1 Cd sausosios masės. O priemolio dirvožemis adsorbuoja esant tai pačiai koncentracijai 206,6 mg•kg-1 Pb ir 107,3 mg•kg-1 Cd s.m... [toliau žr. visą tekstą] / In this master work was investigated cadmium and lead adsorption – desorbtion processes and their interaction impact on thier imobility in soils of different texture. Work subject - two soils of different texture (loam and sandy loam). Work objective – to investigate cadmium and lead adsorption – desorbtion processes and their interaction impact on thier imobility in soils of different texture. Work methods – the investigated soil samples were agitated with Cd (NO3)2, Pb(NO3)2 solutions of different concentrations (0, 0,25, 0,5, 1 mM) as well as with solutions of thier mixtures. The solutions were prepared in the 0,03 M NaNO3 for the maintaining of constant ionic strength. After adsoption experiment, the Cd2+ and Pb2+ ionic concentrations in the equilibrium solution were determined with atomic adsorption spectrometer (AAS). The desorption was investigated in the same samples using 0,05M NH4 – EDTA (pH 7) extractant. In extracts Pb2+ and Cd2+ ionics concentrations were determinadet with AAS. Work results – after investigation observed that sandy soil absorbed 109,9 mg•kg-1 Cd and 206,2 mg•kg-1 Pb, desorbed 61,6 mg•kg-1 Cd and 97,7 mg•kg-1 Pb. And loam soil absorbed 107,3 mg•kg-1 Cd and 206,6 mg•kg-1 Pb, desorbed 57,1 mg•kg-1 Cd and 82,4 mg•kg-1 Pb. Cd in loam soil after Pb adsorption and desorption in Cd-Pb model-sistem the influence was tenuous, while the dorsorption decreased only in loam soil and only in the low concentations (unto 0,5 mM Cd-Pb). Keywords:... [to full text]

AN ECCENTRIC PLACE OF VERY HIGH QUALITY: OSSABAW ISLAND, GEORGIA AS A CONTEXT FOR THE INTERPRETATION OF HISTORICAL, CULTURAL, AND ENVIRONMENTAL CHANGE ON THE ATLANTIC COAST by LINDA ORR KING Under the Direction of Glenn T. Eskew, PhD ABSTRACT This sweeping narrative demonstrates how Ossabaw Island’s landowners, some with a dedicated will and others unwittingly, managed to galvanize social, cultural, scientific, and political forces to preserve its natural environment despite a culture motivated by profit. Although geographically isolated, Ossabaw Island’s owners and inhabitants were active participants within the Atlantic World. Ossabaw’s owners and inhabitants adapted environmental strategies and social ideologies in accommodation not only with Ossabaw’s fragile barrier island ecosystems, but also with Southeastern coastal Georgia’s social and political movements. In particular, this work examines how the advantages of wealth and privilege provided the catalyst that ultimately benefited rather than exploited social and economic conditions on the island, leading Ossabaw Island to become the first barrier island Heritage Preserve on the southern Atlantic Coast. In addition to an analysis of unpublished manuscripts, maps, correspondence, and oral histories, this endeavor expands on the current knowledge about barrier island planters, slaves, freedmen, tenant farmers, lumbermen, boatmen, industrialists, and privileged families. It builds on previous works by including the guests, artists, scientists, writers, and environmentalists who visited the island. Furthermore, it investigates their interaction within political, economic, cultural, religious, and ideological spheres. Ossabaw Island’s indigenous societies, landed gentry, and wealthy owners shaped its cultural and economic identity from the 1560s to the modern day. It analyzes additional materials, including colonial and plantation records, official and personal correspondence, travel narratives, newspaper and magazine articles, and oral histories. This study seeks to expand the discourse on the exchange of sea island economies and societies well beyond the Savannah coastal region of the Atlantic World. The Ossabaw community evolved through conflict and compromise, and eventually encompassed not only sons and daughters of privilege and descendants of former slaves, but also artists, writers, scientists, and scholars from around the world. The central theme of this narrative history is the study of the motivating forces, both natural and synthetic, that shaped Ossabaw Island’s current distinctive cultural, environmental, and educational mission, with the major emphasis placed on the events of the 20th and 21st centuries.