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Strut-and-Tie Evaluation Program (STEP) for the Design of Bridge ComponentsAndi S Vicksman (7026395) 16 August 2019 (has links)
<p>The strut-and-tie method (STM) is a powerful tool used for
the design of D-regions (disturbed regions) of reinforced concrete structures.
Many typical bridge substructure components consist of D-regions and require
the use of the STM for design. Implementation of the STM is more complex than
typical design methods, and engineers are often unfamiliar with the design
process. As a result, designing using the STM is more time consuming than
traditional design methods. The Indiana Department of Transportation (INDOT)
identified a need for a tool that assists with the design of typical bridge
substructure components using the STM. STEP (Strut-and-Tie Evaluation Program)
is a computer program created to fulfill this role. To use the computer
program, engineers input geometric conditions, material properties, and
reinforcement information for a structural component. STEP uses this
information to develop a strut-and-tie model and perform STM design procedures.
A graphical representation of the model and a summary of the design results are
provided as program outputs for the user.</p>
<p> </p>
<p>STEP, created using Excel VBA, is intended to aid in the
design of multi-column bent caps and integral and semi-integral end bent caps.
Within this thesis, an overview of the STM is provided, including the basic
procedures for designing using the STM. An introduction to Excel VBA is also
presented. The document describes the layout and formatting of the computer
program, required user inputs, and program outputs. Furthermore, limitations
and assumptions within the computer program for the substructure components are
also included. Finally, design examples focused on the use of STEP for the
design of a five-column bent cap and an integral end bent cap are
presented. This document can be used as
a resource for engineers when designing bridge substructure components using
STEP. </p>
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Avaliação e identificação de toxicidade (fase I) em nascentes da bacia do rio Mogi-Guaçu, município de Bom Repouso/MG / Toxicity identification evaluation (phase I) in a spring of Mogi-Guaçu river basin, Bom Repouso city/MG, BrazilBarbosa, Danilo Sandro 02 September 2010 (has links)
Localizado na bacia hidrográfica de montante do Rio Mogi-Guaçu, o município de Bom Repouso/MG é considerado estratégico quanto à questão hídrica e econômica, pois apresenta uma elevada quantidade de nascentes (368 nascentes catalogadas) que dão origem aos principais rios da bacia, além de ser um dos principais produtores de batata e morango do país. Estudos anteriores demonstram que esta região tem sofrido perdas quali-quantitativas em seus recursos naturais, especialmente por causa da remoção de cobertura nativa para a expansão de atividades agrícolas e o uso extensivo de defensivos agrícolas, como agrotóxicos e fertilizantes. No presente estudo, a fase I da AIT foi aplicada com o objetivo de evidenciar as características das principais classes de compostos responsáveis pela toxicidade em uma nascente da região de Bom Repouso/MG, Brasil. A toxicidade crônica da amostra bruta, submetida a manipulações como filtração, aeração, ajuste de pH, extração em coluna de octadecil (C18), graduação de pH, adição de EDTA e Tiossulfato de Sódio (\'NA IND.2\'S IND.2\'O IND.3\') foi avaliada por meio de ensaios com Ceriodaphnia dubia. Testes com uma amostra de referência mostraram que o efeito sobre os organismos não era apenas causado por estresse, mas por uma combinação de fatores, como os baixos valores de pH, a baixa dureza da amostra e a presença de substâncias como o ferro, cromo e selenatos, que mesmo em baixas concentrações poderiam ter seu efeito maximizados. No sedimento elutriato um panorama diferente foi visto pois houveram reduções nas graduações de pH e extração em fase sólida, o que também caracteriza combinação de fatores como estresse dos organismos e presença de substâncias orgânicas. / Located in the amount of the Mogi-Guaçu river basin, Bom Repouso City/MG is considered strategic in water resources and economy, because it has high number of springs (368 springs cataloged) and giving rise to the major rivers of the basin, and is among the largest potatoes and strawberry producers. Previous studies have shown that this region has suffered losses in their qualitative and quantitative natural resources, especially because the removal of native forest for the expansion of agricultural activities and the extensive use of agrochemicals such as pesticides and fertilizers. In this study, phase I of TIE was implemented with the aim of highlighting characteristics of major classes of compounds responsible for toxicity in a spring of Bom Repouso City/MG, Brazil. The chronic toxicity of the whole sample and subjected to gross manipulation as filtration, aeration, pH adjustment, solid phase extraction (C18), pH graduated, addition of EDTA and sodium thiosulfate (\'NA IND.2\'S IND.2\'O IND.3\') was assessed by tests with the organism Ceriodaphnia dubia. Tests with a reference sample showed that the effect on the organisms wasnt just caused by stress, but a combination of factors such as low pH and low hardness of the sample and the presence of substances such as iron, chromium and selenate, that even at low concentrations could have maximized effects. Sediment elutriate tests shown a different scenery because there were reductions in the graduated pH and SPE tests, which also reveals a combination of stress factors and presence of organic substances.
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Using chemical and ecotoxicological approaches to assess the ecological risk of pollutants in the Cananeia-Iguape Estuarine Complex, SP, Brazil / Uso de abordagens químicas e ecotoxicológicas para avaliar o risco ecológico de poluentes no Complexo Estuarino de Cananéia-Iguape, SP, BrasilCruz, Ana Carolina Feitosa 11 June 2014 (has links)
This study aimed to study the quality of sediments of the Cananéia-Iguape-Peruíbe estuarine complex (CIP) by using chemical and ecotoxicological analysis, in order to determine if metals from sediments would be bioavailable to benthic organisms. The different tools show that the estuary exhibits signs of alteration due to contamination by metals, which, in their turn, have their origin in mining activities situated upstream of Ribeira de Iguape River. Toxicities were attributed to metals and ammonia suggesting that the combination of natural and anthropic factors may be capable of producing ecological risks. Additionally, this study evidenced that depositional areas appear to move along the estuary, accompanying the displacement of the maximum turbidity zone, which in its turn depends on the freshwater inputs associate to seasonality. These results highlight that oceanographic processes should be considered as important factors that influence on the accumulation of contaminants in estuarine areas. The bioaccumulation test confirmed that these contaminants may be bioavailable to the organisms, especially in the more contaminated sites, and therefore, may be transferred to the food chain, with implications to ecological processes and human health. / Esse estudo teve como objetivo avaliar os sedimentos do Complexo Estuarino Lagunar Cananéia-Iguape-Peruíbe (CIP) através da utilização de análises químicas e ecotóxicologicas, com a finalidade de determinar se os metais dos sedimentos estavam biodisponíveis para organismos bentônicos. As diferentes ferramentas mostraram que o estuário possui mudanças geradas pela contaminação por metais, provenientes de atividades de mineração situadas no alto do Rio Ribeira de Iguape. A toxicidade foi atribuída principalmente aos metais e a amônia, sugerindo que a combinação de fatores naturais e antrópicos são capazes de produzir risco ecológico. Esse estudo evidencia também que ao longo dos estuários, as áreas de deposição mudam acompanhando o deslocamento da zona máxima de turbidez, que está associada com entradas de água doce, regime de chuvas e consequentemente a sazonalidade. Dessa forma, os processos oceanográficos devem ser considerados importantes fatores que influenciam a acumulação de contaminantes em áreas estuarinas. O teste de bioacumulação mostra que esses contaminantes estão biodisponíveis aos organismos, especialmente em áreas mais contaminadas e, portanto, podem ser transferidos ao longo da cadeia alimentar, com implicações nos processos ecológicos e na saúde humana.
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Using chemical and ecotoxicological approaches to assess the ecological risk of pollutants in the Cananeia-Iguape Estuarine Complex, SP, Brazil / Uso de abordagens químicas e ecotoxicológicas para avaliar o risco ecológico de poluentes no Complexo Estuarino de Cananéia-Iguape, SP, BrasilAna Carolina Feitosa Cruz 11 June 2014 (has links)
This study aimed to study the quality of sediments of the Cananéia-Iguape-Peruíbe estuarine complex (CIP) by using chemical and ecotoxicological analysis, in order to determine if metals from sediments would be bioavailable to benthic organisms. The different tools show that the estuary exhibits signs of alteration due to contamination by metals, which, in their turn, have their origin in mining activities situated upstream of Ribeira de Iguape River. Toxicities were attributed to metals and ammonia suggesting that the combination of natural and anthropic factors may be capable of producing ecological risks. Additionally, this study evidenced that depositional areas appear to move along the estuary, accompanying the displacement of the maximum turbidity zone, which in its turn depends on the freshwater inputs associate to seasonality. These results highlight that oceanographic processes should be considered as important factors that influence on the accumulation of contaminants in estuarine areas. The bioaccumulation test confirmed that these contaminants may be bioavailable to the organisms, especially in the more contaminated sites, and therefore, may be transferred to the food chain, with implications to ecological processes and human health. / Esse estudo teve como objetivo avaliar os sedimentos do Complexo Estuarino Lagunar Cananéia-Iguape-Peruíbe (CIP) através da utilização de análises químicas e ecotóxicologicas, com a finalidade de determinar se os metais dos sedimentos estavam biodisponíveis para organismos bentônicos. As diferentes ferramentas mostraram que o estuário possui mudanças geradas pela contaminação por metais, provenientes de atividades de mineração situadas no alto do Rio Ribeira de Iguape. A toxicidade foi atribuída principalmente aos metais e a amônia, sugerindo que a combinação de fatores naturais e antrópicos são capazes de produzir risco ecológico. Esse estudo evidencia também que ao longo dos estuários, as áreas de deposição mudam acompanhando o deslocamento da zona máxima de turbidez, que está associada com entradas de água doce, regime de chuvas e consequentemente a sazonalidade. Dessa forma, os processos oceanográficos devem ser considerados importantes fatores que influenciam a acumulação de contaminantes em áreas estuarinas. O teste de bioacumulação mostra que esses contaminantes estão biodisponíveis aos organismos, especialmente em áreas mais contaminadas e, portanto, podem ser transferidos ao longo da cadeia alimentar, com implicações nos processos ecológicos e na saúde humana.
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Avaliação e identificação de toxicidade (fase I) em nascentes da bacia do rio Mogi-Guaçu, município de Bom Repouso/MG / Toxicity identification evaluation (phase I) in a spring of Mogi-Guaçu river basin, Bom Repouso city/MG, BrazilDanilo Sandro Barbosa 02 September 2010 (has links)
Localizado na bacia hidrográfica de montante do Rio Mogi-Guaçu, o município de Bom Repouso/MG é considerado estratégico quanto à questão hídrica e econômica, pois apresenta uma elevada quantidade de nascentes (368 nascentes catalogadas) que dão origem aos principais rios da bacia, além de ser um dos principais produtores de batata e morango do país. Estudos anteriores demonstram que esta região tem sofrido perdas quali-quantitativas em seus recursos naturais, especialmente por causa da remoção de cobertura nativa para a expansão de atividades agrícolas e o uso extensivo de defensivos agrícolas, como agrotóxicos e fertilizantes. No presente estudo, a fase I da AIT foi aplicada com o objetivo de evidenciar as características das principais classes de compostos responsáveis pela toxicidade em uma nascente da região de Bom Repouso/MG, Brasil. A toxicidade crônica da amostra bruta, submetida a manipulações como filtração, aeração, ajuste de pH, extração em coluna de octadecil (C18), graduação de pH, adição de EDTA e Tiossulfato de Sódio (\'NA IND.2\'S IND.2\'O IND.3\') foi avaliada por meio de ensaios com Ceriodaphnia dubia. Testes com uma amostra de referência mostraram que o efeito sobre os organismos não era apenas causado por estresse, mas por uma combinação de fatores, como os baixos valores de pH, a baixa dureza da amostra e a presença de substâncias como o ferro, cromo e selenatos, que mesmo em baixas concentrações poderiam ter seu efeito maximizados. No sedimento elutriato um panorama diferente foi visto pois houveram reduções nas graduações de pH e extração em fase sólida, o que também caracteriza combinação de fatores como estresse dos organismos e presença de substâncias orgânicas. / Located in the amount of the Mogi-Guaçu river basin, Bom Repouso City/MG is considered strategic in water resources and economy, because it has high number of springs (368 springs cataloged) and giving rise to the major rivers of the basin, and is among the largest potatoes and strawberry producers. Previous studies have shown that this region has suffered losses in their qualitative and quantitative natural resources, especially because the removal of native forest for the expansion of agricultural activities and the extensive use of agrochemicals such as pesticides and fertilizers. In this study, phase I of TIE was implemented with the aim of highlighting characteristics of major classes of compounds responsible for toxicity in a spring of Bom Repouso City/MG, Brazil. The chronic toxicity of the whole sample and subjected to gross manipulation as filtration, aeration, pH adjustment, solid phase extraction (C18), pH graduated, addition of EDTA and sodium thiosulfate (\'NA IND.2\'S IND.2\'O IND.3\') was assessed by tests with the organism Ceriodaphnia dubia. Tests with a reference sample showed that the effect on the organisms wasnt just caused by stress, but a combination of factors such as low pH and low hardness of the sample and the presence of substances such as iron, chromium and selenate, that even at low concentrations could have maximized effects. Sediment elutriate tests shown a different scenery because there were reductions in the graduated pH and SPE tests, which also reveals a combination of stress factors and presence of organic substances.
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The mechanism of inhibition of cap-dependent translation by the Translation Inhibitory Elements (TIE) a3 and a11 in Hox mRNAs / Inhibition de la traduction des ARN messagers Hox par les éléments de type TIEAlghoul, Fatima 26 September 2019 (has links)
Chez les eucaryotes, les ARNm cellulaires subissent une traduction dépendante de la coiffe qui nécessite des facteurs appelés eIFs pour produire des protéines, mais les ARNm Hox sont traduits dans un mécanisme non canonique en raison de deux régulateurs d'ARN dans l'élément 5'UTR appelé Internal Ribosome Entry Site (IRES) qui recrute le ribosome sans le besoin de coiffe, et un élément inhibiteur de traduction (TIE) qui empêche la translation dépendant de coiffe. L'objectif de ma thèse est de déchiffrer le mécanisme de deux éléments TIE a3 et a11 dans les ARNm Hox. Pour cela, nous avons utilisé le système de traduction sans cellules RRL. Notre modèle pour TIE a3 suggère qu'il inhibe la traduction en uORF qui se traduit par un ARNm Hox a3 UTR 5'UTR de pleine longueur et produit un peptide de 9 KDa avec l'implication de eIF2D, un facteur d'initiation non canonique indépendant du GTP. Pour TIE a11, il séquestre le ribosome 80S sur une combinaison de codons start-stop à 19 nucléotides en amont d'une structure de boucle de tige riche en GC qui bloque le 80S au codon stop. / In eukaryotes, cellular mRNAs undergo cap-dependent translation which requires factors called eIFs to produce proteins.However, Hox mRNAs are translated in a non-canonical mechanism due to two RNA regulons in the 5’UTR called Internal Ribosome Entry Site (IRES) element which recruits the ribosome without the need of a cap, and a Translation Inhibitory Element (TIE) which inhibits cap-dependent translation. The objective of my PhD is to decipher the mechanism of two TIE elements a3 and a11 in Hox mRNAs. For that, we used RRL cell-free translation system. Our model for TIE a3 suggests that it inhibits translation to a uORF which translates through full length 5’UTR Hox a3 mRNA and produces a peptide of 9 KDa with the involvement of eIF2D, a non-canonical GTP-independent initiation factor. For TIE a11, it sequesters 80S ribosome on a start-stop codon combination at 19 nucleotides upstream of a GC-rich stem loop structure which blocks the 80S at the stop codon.
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A comparison of design using strut-and-tie modeling and deep beam method for transfer girders in building structuresSkibbe, Eric January 1900 (has links)
Master of Science / Department of Architectural Engineering and Construction Science / Kimberly W. Kramer / Strut-and-Tie models are useful in designing reinforced concrete structures with discontinuity regions where linear stress distribution is not valid. Deep beams are typically short girders with a large point load or multiple point loads. These point loads, in conjunction with the depth and length of the members, contribute to a member with primarily discontinuity regions. ACI 318-08 Building Code Requirements for Structural Concrete provides a method for designing deep beams using either Strut-and-Tie models (STM) or Deep Beam Method (DBM). This report compares dimension requirements, concrete quantities, steel quantities, and constructability of the two methods through the design of three different deep beams. The three designs consider the same single span deep beam with varying height and loading patterns. The first design is a single span deep beam with a large point load at the center girder. The second design is the deep beam with the same large point load at a quarter point of the girder. The last design is the deep beam with half the load at the midpoint and the other half at the quarter point. These three designs allow consideration of different shear and STM model geometry and design considerations.
Comparing the two different designs shows the shear or cracking control reinforcement reduces by an average 13% because the STM considers the extra shear capacity through arching action. The tension steel used for either flexure or the tension tie increases by an average of 16% from deep beam in STM design. This is due to STM taking shear force through tension in the tension reinforcement through arching action. The main advantage of the STM is the ability to decreased member depth without decreasing shear reinforcement spacing. If the member depth is not a concern in the design, the preferred method is DBM unless the designer is familiar with STMs due to the similarity of deep beam and regular beam design theory.
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Approche semi-automatique de génération de modèles bielles-et-tirants / Strut-and-Tie models for the design of non-flexural elements : computational aided approachMendoza Chavez, Gustavo 10 July 2018 (has links)
Dans le domaine des structures en Béton Armé (BA) et plus spécifiquement, lors de la conception d'éléments non-flexibles tels que les corbeaux, les poutres bayonets et les poutres profondes, la Méthode Bielle-Tirant (MBT) présente des avantages par rapport aux algorithmes classiques de calcul de ferraillage basé sur l'analyse FE (par exemple Wood-Armor ou Capra-Maury).La Methode Bielle-Tirant reste une alternative adaptée pour la conception de structures en béton présentant un comportement élastique ou plastique dont le cadre d'application est bien défini dans les codes de conception des structures en béton comme les EuroCodes et les spécifications de conception des ponts AASHTO-LRFD.Néanmoins, cette méthode présente l'inconvénient majeur de nécessiter un investissement important en ressources humaines ou en capacité de calcul pour, respectivement, son application manuelle ou une approche automatique par optimisation de topologie.Le document propose une alternative légère, en termes d'itérations requises, à l'automatisation de la MBT, qui part de l'affirmation que les entretoises résultantes et les attaches d'un modèle ST approprié peuvent être distribuées selon la direction des contraintes principales, $sigma_{III}$ et $sigma_{I}$, obtenus à partir d'un planaire modèle aux EF / Within the field of Reinforced Concrete (RC) structures and more specifically, at the design of non-flexural elements such as corbels, nibs, and deep beams, the rational procedure of conception and justification referred as Strut-and-Tie Method (STM) has shown some advantages over classical algorithms of reinforcement computation based on FE analysis (eg. Wood-Armer or Capra-Maury).The STM remains a suitable alternative for the design of concrete structures presenting either elastic or plastic behaviour whose application framework is well defined in concrete structures’ design codes like the EuroCodes and the AASHTO-LRFD Bridge Design Specifications.Nevertheless, this method has the main inconvenient of requiring a high amount of resources investment in terms of highly experienced personal or in terms of computational capacity for, respectively, its manual application or an automatic approach through topology optimisation.The document proposes a light alternative, in terms of required iterations, to the automation of the STM, which starts from the statement that the resultant struts and ties of a suitable ST model can be distributed according to the direction of the principal stresses, $sigma_{III}$ and $sigma_{I}$ , obtained from a planar or a three-dimensional FE model
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Avaliação do risco ecológico de metais em sedimentos da Baía de Guanabara (RJ), através de um método escalonado baseado em múltiplas linhas de evidências / Ecological risk assessment of metals in sediments of Guanabara Bay (RJ), through a tiered approach based on multiple lines of evidenceCampos, Bruno Galvão de [UNESP] 06 January 2017 (has links)
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Previous issue date: 2017-01-06 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A Baía de Guanabara concentra aproximadamente 70% das indústrias do Estado do Rio de Janeiro. Os resíduos produzidos por essas fontes, somados à carga de esgoto doméstico, transformaram a região em umas das áreas mais poluídas da costa Brasileira. O presente estudo realizou a avaliação do risco ecológico dos metais em sedimentos da Baía de Guanabara, por meio de um método escalonado utilizando múltiplas linhas de evidência: caracterização do sedimento quanto à sedimentologia e concentração de metais, comparação das concentrações ambientais com guias de qualidade de sedimento, ensaios de toxicidade crônica utilizando os organismos Anomalocardia brasiliana e Nitocra sp., ensaios de toxicidade aguda utilizando os organismos Tiburonella viscana, Kalliapseudes schubartii, e Anomalocardia brasiliana. Para comprovar existência de relação causa e efeito entre os metais e a toxicidade, foram empregadas a técnica do TIE, análises multivariadas (PCA) e matrizes qualitativas. Os sedimentos mostraram níveis altos a moderados de metais (Zn, Pb, Cu, Cr) associados com a toxicidade. O TIE revelou que, além dos metais, amônia e compostos orgânicos são contaminantes presentes na região que tem a capacidade de causar toxicidade. Desse modo constatou-se que os metais constituem uma importante classe de contaminantes para a Baía de Guanabara, os quais, além de estarem presentes em altas concentrações, interagem com outros contaminantes e são também (co)responsáveis por efeitos biológicos negativos. / The Guanabara Bay (GB) comprises approximately 70% of the industries of Rio de Janeiro State. The wastes produced by these sources, combined with the domestic sewage loads, have transformed the region into one of the most polluted areas of the Brazilian coast. The present study evaluated the ecological risk of metals in sediments from the GB by the use of a tiered approach. The chosen method combines the following lines of evidence: geochemistry, comparison of environmental concentrations of metals with sediment quality guidelines, chronic sediment toxicity tests with Anomalocardia brasiliana and Nitocra sp.; and acute sediment toxicity tests with Tiburonella viscana, Kalliapseudes schubartii, and Anomalocardia brasiliana. To verify the existence of cause and effect relationships between metals and toxicity, the Toxicity Identification Evaluation (TIE) technique, multivariate analysis (PCA) and qualitative matrices were used. Sediments showed high to moderate levels of metals (Zn, Pb, Cu, Cr) associated with toxicity. In addition, the TIE has revealed that metals, ammonia and organic compounds contribute to cause sediment toxicity. We concluded that metals are an important class of contaminants for the GB, together with other chemicals, as they are present in high concentrations, interact with other substances and are (co)responsible for the negative biological effects. / FAPESP: 2015/13143-0
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Strut-and-Tie Modeling of Multistory, Partially-Grouted, Concrete Masonry Shear Walls with OpeningsBuxton, Jeffrey Ryan 01 April 2017 (has links)
Construction practices are constantly evolving in order to adapt to physical locations and economic conditions. These adaptations may result in more cost-effective designs, but may also come at a cost of strength. In masonry shear walls, it is becoming more common to reduce the amount of grouting from every cell to only those with reinforcement, a practice known as partial-grouting. Partially-grouted masonry responds differently and in a more complex matter to lateral loads as compared to fully-grouted masonry. The response is made even more complex by wall discontinuities in the form of openings. The main objective of this study is to validate the strut-and-tie procedure for the in-plane lateral strength prediction of partially-grouted, multistory, reinforced concrete masonry walls with openings. The research included testing six three story, half-scale masonry shear walls. Half of the walls had door openings while the other half had window openings. The configurations were selected to represent typical walls in multi-story buildings. The measured lateral strength was compared to estimations from the equations in the US masonry code and to those from an equivalent truss model and a strut-and-tie model. The results show that the U.S. masonry code equations over predicts while the equivalent truss model under predicts the lateral strength of the walls. The results further show that the strut-and-tie model is the most accurate method for lateral strength prediction and is able to account for wall openings and partial-grouting.
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