The glass forming ability (GFA) of the lightweight Mg65Cu25Y10 alloy has been widely studied. This alloy contains a medium sized Mg matrix (0.16 nm in atomic radius), a small sized Cu (0.14 nm) and a large sized Y (0.18 nm). The glass transition temperature Tg, supercooled temperature range

The samples in this study were collected from the drilling cores W-2 and S-4 obtained from the slope-stability monitoring project inside the campus of NSYSU. The Sheng-Li (SL) core was drilled for groundwater monitoring project in the northern of Kaohsiung city. The mudstone sections in these three cores were sampled to reconstruct the sedimental history of the southwestern Taiwan. This study mainly contains 3 parts: firstly we dated the downcore records based on nannobiostratigraphy. Secondly, we analyzed the benthic foraminiferal assemblages in sedimentary sequences. Finally we chose specific benthic species and analyzed the shell trace metals, especially Mg/Ca and Sr/Ca ratio with an ICP-MS. Overall the mudstone sections analyzed in this study fall in the biostratigraphic range of small Gephyrocapsa Subchron, which spreads within 1242ka~1031ka according to the previous report. The age range in W-2 was further constrained within 1186ka~1065ka based on the oxygen isotope stratigraphy (Tseng, 2004). There are four dominant benthic species, including Bulimina spp., Uvigerina spp., Brizalina tainanesis and Siphogenerina raphanus in Cores W-2 and S-4. There are five dominant benthic species, including Brizalina spp., Pseudorotalia spp., Siphogenerina raphanus, Amphicoryna scalaris and Brizalina alata in Core SL. The benthic foraminiferal shell Mg/Ca ratios obtained from Core W-2 indicate the bottom water temperature are between 6 - 12¢J, which reflects the paleo water depth had varied between 300 - 700m. It also indicates that strata were uplifted and the deposition depth become shallow.

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The study of dross in ductile cast iron main shafts was performed at Global Castings Guldsmedshyttan AB and presented in this master thesis. The purpose of the study was to obtain answers to why dross defects were present in some of the foundry's casted main shafts, with the main problem located at the flange of the shaft. The chemical composition of the dross formations and which steps in the casting process that increased the dross formation were of interest. The study only included dross in main shafts manufactured at Global Castings Guldsmedshyttan AB. Dross particles form when elements such as Mg, Ca, Si and Mn react with O. These elements, which are highly reactive to O, are used in ductile cast irons to achieve the spheroidal graphite nodules that regulate the cast materials ductile properties. If a higher amount of dross particles has formed, the particles will start to cluster, resulting in a growing dross formation. Dross formations works as surface crack initiation points and reduces the castings fatigue strength and ductility. During the study it was seen that the cause of dross formations is a combination of many parameters increasing the melts exposure to O resulting in dross defects. The dross formations could be connected to worn out ladles, low melt temperatures, incorrect additions of Mg treatment, lack of an extra slag removal station and finally turbulence as the melt were poured into the mould. At Global Castings Guldsmedshyttan AB a greater part of the main shafts containing dross defects were a result of worn out ladles and low melt temperatures. The types of dross found in the main shaft material were mainly Mg, Ca, Si and Al which had reacted with O. S bonded with Mg and Ca was also detected in the dross formations. It was shown that the dross particles could be derived from charge material, Mg treatment and inoculation. To avoid dross defects the first step would be to set up an extra slag station, shorten the interval of maintenance of the ladles and to better adjust the melt temperature to the condition of the specific ladle. To minimize dross due to excess Mg a better controlled process would be recommended with an increased number of monitored manufacturing parameters. / Studien av dross i axlar tillverkade av segjärn gjordes hos Global Castings Guldsmedshyttan AB och presenteras i denna examensrapport. Syftet med studien var att hitta anledningar till varför drossdefekter bildas i flänsen på vissa av gjuteriets tillverkade axlar. Drossens kemiska komposition likväl de steg i tillverkningsprocessen som inverkade på drossbildning var av intresse. Studien inkluderade endast drossdefekter i axlar tillverkade av Global Castings Guldsmedshyttan AB. Drosspartiklas bildas när till exempel Mg, Ca, Si och Mg reagerar med O. Dessa ämnen, vilka är väldigt reaktiva med syre, används vid framställning av segjärn för att de sfäriska grafitnodulerna som starkt reglerar materialets duktila egenskaper ska bildas. Ett större antal drosspartiklar i en smälta leder till kluster av dross vilka växer i takt med att nya partiklar bildas. Dross fungerar som sprickinitieringspunkter i gjutgodsytor och reducerar godsets utmattningshållfasthet och duktilitet.   Under studien kunde det ses att dross bildas på grund av en kombination av parametrar som ökar smältans exponering av syre vilket resulterar i drossdefekter. Drossdefekter kunde kopplas till slitna skänkar, låga smälttemperaturer, felaktig mängd magnesiumbehandling, brist på en extra slaggstation och slutligen turbulens när smätan hälls i formen. Hos Global Castings Guldsmedshyttan AB är en stor del av axlarna med drossdefekter ett resultat av framför allt slitna skänkar och låga smälttemperaturer. Vid analys sågs det att ett antal olika typer av drosspartiklar kan bildas i det duktila gjutjärn som används till axlarna; främst Mg, Ca, Si och Al som reagerat med O. Mg och Ca som bundit med S kunde också hittas i vissa av de studerade drossformationerna. Det kunde visas att den kemiska kompositionen i drosspartiklarna var härrörande från grundmaterialet, magnesiumbehandlingen och ympmedlet.  Ett första steg Global Castings Guldsmedshyttan AB skulle kunna ta för att undvika drossdefekter är att ha en extra slaggstation, införa tätare underhåll av skänkarna och bättre anpassa smälttemperaturen till skicket på den specifika skänken. För att minimera dross som bildats på grund av ett överskott av Mg skulle en mer kontrollerad process rekommenderas med ett ökat antal bevakade tillverkningsparametrar.

The proportion of authigenic to detrital clay minerals in terrestrial sediments is variable. It has previously been hypothesized that pure Mg-silicates in regions such as Amboseli Basin in Kenya occur due to the absence of Al-rich detritus. We tested this by replicating two Mg-silicate synthesis experiments while adding Al-rich smectite. The first study produced an X-ray amorphous Mg-silicate gel, with little response to addition of Al-rich smectite. The second experiment shifted the 060 peak associated with clay octahedral sheets, suggesting we synthesized trioctahedral domains in a smectite structure. Peak height increased linearly with more heating, indicating crystallinity changes. These results confirm that Al-rich detritus can influence the mineralogy of authigenic clays in saline, alkaline settings. By examining how clay neoformation is affected by silica saturation, we can better understand how the clays found in Neogene lacustrine environments are formed and the climate and of that time.

The Bahamian Archipelago is one of the few locations in the world where ooid formation is actively occurring. Ooid cortices from six locations in the region were incrementally dissolved and analyzed for 14C, δ18O, δ13C, Mg/Ca and Sr/Ca ratios. Ooids were examined under SEM after each step in the incremental analyses to characterize the nature of dissolution. Radiocarbon dating indicates that surface ooids began forming across the Archipelago between 1000 and 2800 yr BP and continue to form today. The ooids have the same pattern of microboring alteration across the region. The surface and outer cortex of the ooids are punctuated with unfilled microborings, whereas the inner cortex contains two morphologies of aragonite cement filling the microborings. The two morphologies of cement form in association with two different species of cyanobacteria, one is Solentia sp. the other is interpreted to be Hyella sp.. The chemistry of ooids from across the region is remarkably similar. δ18O and δ13C values for all samples vary directly, having a slope of approximately 1. The outer cortex has low δ18O and δ13C values of -3.4‰ and 0.2‰ respectively, whereas the δ18O and δ13C values of the inner cortex are high with values of 1.9‰ and 6.8‰ respectively. The presence of aragonite cement in microborings in the inner cortex increases the overall isotopic composition of both oxygen and carbon in the ooid, causing it to appear close to equilibrium with seawater. The isotopic variation in δ18O and δ13C within the cortex can be characterized as a mixing line between the low values in the unaltered ooid laminae and the aragonite cement in the microborings. The most exterior portion of the ooid has very high Mg/Ca values and is interpreted as an amorphous calcium carbonate (ACC) coating. There are two other phases in the cortex, both being aragonite. The outer cortex has a higher Mg/Ca ratio and lower Sr/Ca ratio than the inner cortex. This difference in chemistry is a result of the presence of aragonite cement in the inner cortex. Stable isotopic and trace element results coupled with SEM investigations indicate that microbes do not play a role in ooid formation, but instead alter the texture and chemistry of ooids after they have formed. This alteration occurs throughout the entire shoal region. A new model of ooid formation is proposed whereby a veneer of ACC precipitates on an ooid while it is at the sediment-water interface (the active phase). This veneer of ACC later recrystallizes to aragonite needles, possibly nucleating on organic material and a new cortex layer is formed. Observations from this study lead to a deeper understanding of the chemical processes involved in ooid genesis, which allows for a better understanding of paleoenvironments hosting ooid formation. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2009-01-27 13:29:42.765

Οι νικοτινικοί υποδοχείς της ακετυλοχολίνης (nAChRs), μέλη της υπερ-οικογένειας των πενταμερών χημειοελεγχόμενων ιοντικών καναλιών (LGICs), είναι διαμεμβρανικές γλυκοπρωτεΐνες μεγέθους ~290 kDa. Ανάλογα με την τοπολογία και τα φαρμακολογικά τους χαρακτηριστικά, διακρίνονται σε μυϊκού και νευρικού τύπου υποδοχείς. Οι μυϊκού τύπου nAChRs βρίσκονται στα ηλεκτρικά όργανα των ιχθύων Torpedo sp. και στις νευρομυϊκές συνάψεις των σπονδυλωτών, όπου μεταβιβάζουν τις νευρικές ώσεις στους μύες. Αποτελούνται από πέντε ομόλογες υπομονάδες που σχηματίζουν ένα κανάλι, με στοιχειομετρία (α1)2βγδ στα έμβρυα ή (α1)2βεδ στους ενήλικες. Κάθε υπομονάδα αποτελείται από: (α) ένα αμινο-τελικό εξωκυτταρικό τμήμα (ECD) μήκους ~210–220 αμινοξέων (β) τέσσερις μικρές (15–20 αμινοξέα μήκος η καθεμιά) υδρόφοβες διαμεμβρανικές περιοχές (M1–M4) και δύο μικρές υδρόφοβες θηλιές, μεταξύ των M1–M2 και M2–M3 (γ) μια υδρόφιλη κυταρροπλασματική θηλιά που ποικίλει σε μέγεθος (100–150 κατάλοιπα) και αμινοξική σύσταση μεταξύ των υπομονάδων, ανάμεσα στην Μ3 και Μ4 περιοχή, και (δ) ένα μικρό (4–28 αμινοξέα) υδρόφιλο καρβοξυ-τελικό άκρο εξωκυτταρικά. Οι μυϊκού τύπου nAChRs εκτός από την φυσιολογική τους δράση εμπλέκονται και στην αυτοάνοση νόσο μυασθένεια (myasthenia gravis-MG). Τα αυτοαντισώματα των μυασθενικών προσδένονται στην εξωκυτταρική περιοχή του AChR και η πλειοψηφία τους φαίνεται να στοχεύει την α1 υπομονάδα και συγκεκριμένα την κύρια ανοσογόνο περιοχή της-MIR. Επιπλέον, στην εξωκυτταρική περιοχή της α1 υπομονάδας εντοπίζεται και η περιοχή που συμμετέχει στον σχηματισμό της θέση πρόσδεσης της ακετυλοχολίνης και άλλων χολινεργικών προσδετών. Το α1 ECD του ανθρώπινου nAChRs έχει ήδη εκφραστεί, απομονωθεί και χαρακτηριστεί από υπερκείμενο καλλιέργειας του ζυμομύκητα Pichia pastoris ως μονομερές, υδατοδιαλυτό και λειτουργικό πρωτεϊνικό μόριο. Η ικανότητά του να προσδένει αντι-AChR αυτοαντισώματα βρέθηκε μέτρια, και για τον λόγο αυτό στην παρούσα εργασία εκφράστηκε σε ένα ανώτερο εξελικτικά σύστημα από αυτό του Pichia pastoris, με σκοπό την έκφραση μορίων με καλύτερη αναδίπλωση, που να προσομοιάζουν περισσότερο με την φυσική τους διαμόρφωση, καθώς επίσης και την παραγωγή ικανοποιητικής ποσότητας πρωτεΐνης, ώστε να είναι εφικτή η δομική της μελέτη. Ως ετερόλογο σύστημα έκφρασης, χρησιμοποιήθηκαν κύτταρα εντόμων του είδους Trichoplusia ni (High Five), τα οποία ήταν σταθερά μετασχηματισμένα ως προς το ανασυνδιασμένο α1 ECD πολυπεπτίδιο. Αναλυτικότερα, το ECD της α1 υπομονάδας εκφράστηκε στα δύο συστήματα και στην συνέχεια καθαρίστηκε και απομονώθηκε με χρωματογραφία συγγένειας και μοριακής διήθησης. Το High Five α1 ECD εκφράστηκε ως υδατοδιαλυτό μόριο σε ικανοποιητική ποσότητα ενώ η χρωματογραφία μοριακής διήθησης και οι μελέτες δυναμικής σκέδασης του φωτός έδειξαν επιπλέον πως εκφράζεται ως μονομερές. Ορισμένοι χολινεργικοί προσδέτες προσδένονται στο High Five α1 ECD, επιβεβαιώνοντας πως η διαμόρφωσή του προσομοιάζει με του ανθρώπινου nAChR. Με πειράματα ELISA και ραδιοανοσολογικού προσδιορισμού, προέκυψε πως το High Five α1 ECD δεσμεύει μεγαλύτερο ποσοστό αντι-nAChR μονοκλωνικών αντισωμάτων και αυτοαντισωμάτων από τον ορό μυασθενικών, συγκριτικά με το Pichia pastoris α1 ECD. Σύμφωνα με τα αποτελέσματα της εργασίας αυτής, το ανασυνδυασμένο α1 ECD του ανθρώπινου nAChR, εκφρασμένο σε κύτταρα εντόμων High Five, προσομοιάζει περισσότερο με την φυσική διαμόρφωση του nAChR. Επιπλέον, το ετερόλογο σύστημα έκφρασης των High Five κυττάρων είναι αποδοτικά καλύτερο σε σύγκριση με αυτό του ζυμομύκητα Pichia pastoris. Αυτό, καθιστά το High Five α1 ECD καταλληλότερο για δομικές μελέτες υψηλής ανάλυσης, που θα βοηθήσουν στην επίλυση της τρισδιάστατης δομής του υποδοχέα, αλλά και για την ανάπτυξη μιας ειδικής αντιγονοειδικής θεραπείας για τη μυασθένεια. / Nicotinic acetylcholine receptors (nAChRs), members of the superfamily of pentameric ligand-gated ion channels (LGICs), are transmembrane glycoproteins (Mr ~290 kDa). According to their topology and their pharmacological properties, nAChRs are divided into muscle-type and neuronal-type nAChRs. The muscle-type AChRs are located in fish electric organs as well as in the neuromuscular junction, where they transmit electrical signals from the nervous system to the vertebrate skeletal muscles. They consist of five homologous subunits forming a channel with stoichiometry (α1)2βγδ in embryos or (α1)2βεδ in adults. A nAChR subunit consists of: (a) a N-terminal extracellular domain (ECD) which is ~210–220 amino acids long; (b) four short (15–20 amino acids long) hydrophobic transmembrane segments (M1–M4) and two small hydrophilic loops, linking segments M1–M2 and M2–M3; (c) a hydrophilic cytoplasmic loop varying in size (100–150 residues) and sequence among different type of subunits, which located between M3 and M4 segment, and (d) a C-terminal short (4–28 amino acids) hydrophilic extracellular segment end. Muscle type nAChRs are also involved in the autoimmune disease myasthenia gravis (MG). Αutoantibodies in MG bind to the extracellular domain of the AChR and their majority target the α1 subunit and more specific the major immunogenic region (MIR). Moreover, the ECD of the α1 subunit bears the binding sites for acetylcholine and other cholinergic ligands. The human nAChR α1 subunit ECD has been expressed, isolated and characterized in the yeast Pichia pastoris as a monomer, water-soluble and functional molecule, with a medium ability to bind antibodies against AChR. In this project, the human nAChR α1 subunit ECD was expressed in an evolutionary higher protein expression system compared to Pichia pastoris system, in order to express molecules with better conformation, close to that of the native protein and to produce considerable amounts of protein for structural studies. In more details, we have used insect cells from the species Trichoplusia ni (High Five), which were stably transformed with the α1 ECD polypeptide. The α1 ECD of the human muscle nAChR, was expressed in both systems and was isolated and purified by affinity chromatography and fast protein liquid chromatography analysis (FPLC). The recombinant High Five α1 ECD was expressed as a water-soluble molecule in sufficient quantities. FPLC and dynamic light scattering analysis determined it to be monomer. Several cholinergic ligands were found to bind to High Five α1 human ECD confirming the native-like conformation of the protein. High Five α1 ECD was subsequently found to bind better conformation-dependent anti-nAChR mAbs than the Pichia pastoris α1 human ECD, as determined by ELISA and radioimmunoassay analysis. The binding of High Five α1 human ECD to anti-nAChR autoantibodies from MG patients, was also found to be better than the Pastoris pastoris α1 human ECD. These results indicate that the recombinant α1 human ECD, expressed in High Five cells, has a more native-like conformation than Pichia pastoris α1 ECD, being suitable for high resolution structural studies, in order to reveal the structure of the human nAChR and for the development of an antigen specific therapy for MG.

Orientador : Prof. Dr. Sylvio Péllico Netto / Coorientador : Prof. Dr. Márcio Coraiola / Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Programa de Pós-Graduação em Engenharia Florestal. Defesa: Curitiba, 24/02/2017 / Inclui referências : f. 201-205 / Resumo: As florestas nativas constituem um ecossistema complexo, fontes de inúmeros recursos, cujo equilíbrio pode ser facilmente alterado por perturbações expressivas no meio, como, por exemplo, ações antrópicas. No entanto, o manejo de modo racional, visando à proteção de suas características naturais, é a melhor alternativa para sua perpetuidade e conservação. No âmbito da extensão das florestas, o Brasil possui grande representatividade mundial devido sua extensa área de florestas naturais, que representam 54,4% do território nacional, segundo o Serviço Florestal Brasileiro. Nesse sentido, são essenciais estudos que possibilitem uma adequada avaliação e quantificação desses recursos, compreendidos no presente estudo como variáveis quantitativas e qualitativas e representadas pelos cálculos e estimativas que envolvem: valor de cobertura, valor de importância, volume de madeira, prognose da estrutura diamétrica, além de análises relacionadas aos aspectos de mortalidade, ingresso e estrutura horizontal da floresta. Os dados utilizados para o desenvolvimento deste trabalho são oriundos de um inventário florestal contínuo, realizado em um período de 13 anos, com repetição total anual de 1996 a 2001 e bianual até 2009, em um fragmento de Floresta Estacional Semidecidual na Fazenda Reata, integrante ao projeto PELD, localizada no município de Cássia, MG. Foram considerados indivíduos amostrados, as árvores com diâmetro a altura do peito igual ou superior a 10 cm das espécies identificadas botanicamente. O conjunto total dos dados foi composto por 9 parcelas quadradas, cada uma delas com 1 ha de área, que serviu de base para a aplicação da análise do volume, valor de importância e valor de cobertura da floresta, e a prognose da estrutura diamétrica. Cada parcela é composta por 100 subparcelas quadradas, que compuseram a estrutura da nova proposta para o valor de cobertura. Como principais resultados, pode-se citar que para o valor de cobertura, a nova metodologia (VCW&P) proposta se mostrou satisfatória na análise da dinâmica do índice, em relação às demais metodologias avaliadas (proposta por Brau-Blanquet e Amaral), devido ter a dominância como principal parâmetro de influência. Para o valor de importância, a metodologia proposta por Péllico Netto evidenciou espécies como as de maior importância da floresta aquelas que apresentaram as maiores médias e amplitude de altura do povoamento, apesar da espécie ser de baixa densidade, ao contrário do que foi demonstrado por meio da metodologia de Curtis e McIntosh. A composição do volume expressou uma maior variabilidade entre as parcelas, em relação a demais tipologias florestais, tendo a mortalidade em relação ao número de ingressos como principal fator da variação do volume. No entanto, apresentou a maior concentração do volume total da floresta em um menor número de espécies, corroborando com o que está publicado sobre outros fragmentos florestais. A projeção da estrutura diamétrica do povoamento mostrou uma tendência de aumento no número de indivíduos, tendo a metodologia de razão de movimentação de diâmetro, com uma amplitude de 5 cm, apresentando os melhores resultados para a prognose. A partir dessa metodologia mantendo-se a mesma amplitude e realizando a prognose para o ano de 2022, para a floresta como um todo e para as espécies Cariniana legalis, Pterocarpus violaceus e Croton floribundus, apresentaram aumento no número de indivíduos, tendo essa última espécie registrado o menor valor e alteração em sua estrutura diamétrica. Palavras Chave: valor de importância; valor de cobertura; volume total; Floresta Estacional Semidecidual; projeção; estrutura diamétrica / Abstract: The native forests constitute a complex ecosystem, sources of countless resources, whose balance can be easily altered by disturbances in the expressive means, such as, for example, anthropological actions. However, the management in rational way, aiming to protect its natural characteristics, is the best alternative for its perpetuity and conservation. In the context of an extension of forests, Brazil has great world representation due to its extensive area of natural forests, which represents 54.4% of the national territory, according to the Brazilian Forest Service. In this sense, studies are essential to allow a proper assessment and quantification of these resources, which are included in the present study, as quantitative and qualitative variables expressed by calculations and estimates that involve: value of coverage, value of importance, volume of wood, the prognosis of the diametric structure, as well as analysis relating to mortality, ingrowth and horizontal structure of the forest. The data used for the development of this work are derived from a continuous forest inventory, conducted in a period of 13 years, with total annual replacement from 1996 to 2001 and, from there, biannually until 2009, in a fragment of Semideciduous Tropical Forest in Reata Farm, integrated to the project PELD, located in the municipality of Cassia, MG. Trees with diameter at breast height equal to or greater than 10 cm were considered for the sampling of the species identified botanically. Total data set was composed of 9 square plots, each with 1 ha of area, which served as the basis for the analysis of volume, importance value, coverge value and prognosis of the diametric structure of the forest. Each portion is composed of 100 square plots, which underlie the informational structure for a new coverage value. As main results, we can mention that for the coverage value, the new proposed methodology (VCW&P) was satisfactory in analyzing the dynamics of the index, in relation to the other evaluated methodologies (proposed by Brau- Blanquet and Amaral) due to the dominance as the main parameter of influence. For the importance value, the methodology proposed by Péllico Netto has identified species of greater importance of the forest, those that presented the highest average and height amplitude in the stand, even when these showed low density, contrary to what has been evaluated by means of the Curtis and McIntosh's methodology. The volume composition expressed more variability between plots, in relation to other forest typologies, having the relationship mortality/number of ingrowth as a main factor of volume variation. The forest total volume is concentrated in a small number of species, corroborating with what is already published on other forest fragments. The projection of the stand diametric structure showed a tendency toward an increase in the number of individuals. Using the ratio of diameter movement method, with amplitude of 5 cm, showed the best results for the prognosis. From this methodology, maintaining the same amplitude and effectuating the prognosis to the year 2022, for the forest as a whole and for the species Cariniana legalis, Pterocarpus violaceus and Croton floribundus, showed an increase in the number of individuals, and for this last species occurred the smallest value and change on its diameter structure. Keywords: importance value; value of coverage; total volume; Seasonal Semideciduous Forest; projection; diameter structure.

Orientador: Anderson Luís Hebling Christofoletti / Banca: Jussara dos Santos Rosendo / Banca: Diego Correa Maia / Resumo: As inundações constituem um dos impactos ambientais mais observados nas áreas urbanas. A incidência destes eventos varia conforme as características climáticas e socioambientais das cidades. Esta pesquisa teve como objetivo principal avaliar o risco a enchentes, a alagamentos e ao escoamento superficial concentrado na área urbana de Ituiutaba (MG), a partir de suas condicionantes físicas e de suas características socioespaciais, inerentes ao processo de urbanização. Para isto, realizaram-se análises do geossistema urbano; da variabilidade pluvial com enfoque na recorrência das precipitações extremas; das ocorrências de transtornos associados ao impacto pluvial e da percepção do problema por parte da população atingida e do poder público municipal. Verificou-se que os impactos hidrometeóricos concentram-se durante os meses da primavera e do verão, quando as chuvas são mais abundantes. Em média, treze episódios chuvosos com volume a partir de 30mm/24h acontecem a cada ano, representando, assim, um potencial de danos ao ambiente urbano. De forma mais esporádica, acontecem ainda precipitações mais intensas, por volta de 90mm/24h, com potencial de impacto muito maior. Os arquivos das ocorrências do Corpo de Bombeiros e as reportagens publicadas pela imprensa local constituíram importantes fontes para o mapeamento e análise dos impactos. Como consequência desses eventos, tem-se na área central da cidade e bairros adjacentes, que são mais impermeabilizados, as ocorrências de escoame... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Floods are one of the most observed environmental impacts in urban areas. The incidence of these events varies according to the climatic and socio-environmental characteristics of the cities. The main objective of this research was to evaluate the risk to the overflows, the floods and the concentrated surface runoff in the urban area of Ituiutaba (MG), based on its physical conditioning aspects and its socio-spatial characteristic, which are inherent in the urbanization process. For that purpose, some analyzes of the urban geosystem, the rainfall variability with focus on the recurrence of the extreme precipitations, the occurrences of disturbances associated with the rainfall impact and the perception of the problem by the affected population and the municipal public power were carried out. It was found that the hydrometeoric impacts are concentrated in the spring and summer months, when the rains are more abundant. On average, thirteen rainy episodes with a volume from 30mm/24h happen each year, which represents a potential for damages to the urban environment. More sporadically, there are some intense precipitations, around 90mm/24h, with a much greater potential impact. The Fire Department's archives and the news published in the local press were important sources for the mapping and analysis of the impacts. As a consequence of these events, there are in the city centre area and adjacent neighborhoods, which are more waterproofed spaces, the occurrences of concentrated su... (Complete abstract click electronic access below) / Mestre