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RBI, referring to a risk-based approach to inspection planning, is an established pipeline integrity management method. Both corrosion and dents are the primary threats to pipeline integrity. However, they are often treated separately in RBI without considering their interactions. This coupling may lead to a synergic effect on integrity degradation. The present study proposes an RBI planning framework for pipelines considering external corrosion and dents. Time-dependent pipeline deterioration by dents and corrosion is modeled probabilistically using a Dynamic Bayesian Network (DBN), in-line inspection (ILI) data, and corrosion propagation knowledge. Two failure scenarios (leakage and burst) are considered. The hybrid method, integrating Monte Carlo Simulation (MCS) and Latin Hypercube Sampling (LHS) technique, estimates the pipeline's Probability of Failure (PoF) over time. The pipeline failure risk is quantified by monetizing the Consequence of Failure (CoF). An optimization model of loss-maintenance total expected cost is introduced to determine the optimum inspection period using maximum acceptable risk (MAR) and the lowest total expected cost. A cost-benefit analysis (CBA) is finally implemented to choose appropriate risk reduction measures. The proposed framework is robust and well-validated by a case study on an in-service pipeline., Safety and Security Science more...

This paper proposes an analytical model that uses historical damage dimension data to deduce physical impactor characteristics (size and energy) that has caused a certain resulting damage. Maintenance tasks occur in operations due to impact, however the source of the damage caused in the event remains in most cases unknown. Consequently, by inferring what has caused a certain type of damage from the distribution of the damage type and severity relative to impactor types, maintainers can be better prepared in terms of what to expect from a given impactor source. The developed model introduces a novel transition deformation region between the local deformation and the global plate deflection, allowing for fast and accurate predictions of the impact event. Using the known aluminium structural properties and damage dimensions, the damage data is converted into impactor data. The model is applied in a case study using 120 fuselage dent damages dimensions (length, width, and depth) from a Boeing 777 fleet. The results show that the model deduces impactor characteristics for 94% of the considered damages, ranging up to 240 J and 110 mm for impactor energy and radius respectively., Air Transport & Operations, Aerospace Structures & Computational Mechanics more...

Durant molt de temps, es pensava que el registre fòssil dels taurons triàsics a Espanya era inexistent. No obstant això, recents estudis en les serralades Ibèriques, Bètiques i Costero-Catalana han demostrat que en les aigües que banyaven la península durant este període els taurons eren igual d’abundants que el d’altres localitats Europees del Triàsic., Durante mucho tiempo, se pensó que el registro fósil de los tiburones triásicos en España era inexistente. Sin embargo, recientes estudios en las cordilleras Ibéricas, Béticas y Costero-Catalana han demostrado que en las aguas que bañaban la península durante este periodo los tiburones eran igual de abundantes que el de otras localidades Europeas del Triásico., For a long time, it was thought that the fossil record of the Triassic sharks in Spain was non-existent. However, recent studies in the Iberian, Betic and Coastal-Catalan Ranges have shown that in the waters that bathed the peninsula during this period, sharks were as abundant as that of other European locations in the Triassic. more...

Durant molt de temps, es pensava que el registre fòssil dels taurons triàsics a Espanya era inexistent. No obstant això, recents estudis en les serralades Ibèriques, Bètiques i Costero-Catalana han demostrat que en les aigües que banyaven la península durant este període els taurons eren igual d’abundants que el d’altres localitats Europees del Triàsic., Durante mucho tiempo, se pensó que el registro fósil de los tiburones triásicos en España era inexistente. Sin embargo, recientes estudios en las cordilleras Ibéricas, Béticas y Costero-Catalana han demostrado que en las aguas que bañaban la península durante este periodo los tiburones eran igual de abundantes que el de otras localidades Europeas del Triásico., For a long time, it was thought that the fossil record of the Triassic sharks in Spain was non-existent. However, recent studies in the Iberian, Betic and Coastal-Catalan Ranges have shown that in the waters that bathed the peninsula during this period, sharks were as abundant as that of other European locations in the Triassic. more...

Tankozide cilindrične strukture imaju veoma visoku primenu u industriji. Pošto su obično opterećene na aksijalni pritisak, najčešći uzrok njihovog otkaza je pojava izvijanja. U ovom članku se prikazuje numerička analiza izvijanja tankozide cilindrične strukture izrađene od legure aluminijuma sa imperfekcijom u vidu udubljenja na sredini strukture i eksperimentalna verifikacija rezultata dobijenih tom analizom. Numerička analiza je odrađena pomoću softvera ANSYS 16.2, a eksperimentalna ispitivanja pomoću hidraulične prese Armavir, PSU-50, na kojoj je uzorak podvrgnut aksijalnom pritisku čiji se intenzitet postepeno povećavao do pojave izvijanja. Poređenjem rezultata eksperimenta uočeno je značajno smanjenje vrednosti kritičnog napona na izvijanje između epruveta bez imperfekcije i epruveta sa imperfekcijom od 2 mm, dok su vrednosti kritičnog napona za epruvete sa imperfekcijama od 2 mm i 4 mm približne., Thin-walled cylindrical shells are commonly used in numerous branches of industry. Since they are subjected to axial load, the most common cause of their failure is buckling. This paper provides numerical analysis and experimental verification of the buckling of the thin-walled aluminium alloy cylindrical shell with special regard to the influence of dent, positioned in the middle of the shell. Numerical simulation was performed using ANSYS 16.2, and experimental verification was performed by means of hydraulic press Armavir, PSU-50, which was used to subject the specimen to the increasing axial load until the occurrence of buckling. Comparing the results it was concluded that there is significant decrease of the buckling resistance if compared the values of the specimen with no dent, and the specimen with 2 mm deep dent. On the contrary, resistance of the 2 mm and 4 mm dented specimen is quite similar. Position and shape of the deformations occurred due to buckling are matching if experimental and numerical results are compared. more...

There is a growing trend in production of early maturity maize hybrids as far north and on higher altitudes as possible, even in regions where they were not previously cultivated. Thus, an increased demand at the global market for early maturity maize hybrids of FAO 100 and 200 is present. These hybrids are able to mature under not so favourable temperature conditions. The experiments were performed in Planinica - central part of Serbia at 650 m above sea level, during four years (2001-2004). Nine Zemun Polje (ZP) dent and nine flint hybrids of the FAO 100 and 200 were observed. The highest average grain yield (7.19 t ha(-1)) was recorded in 2002 and it was also high in 2004 was (7.18 t ha(-1)), while in the remaining two years, yields were significantly lower (6.50 t ha(-1) - 2001 and 4.32 t ha(-1) - 2003). In more productive years two dent hybrids: ZP 290 (9.90 t ha(-1) in 2002) and ZP 251 (10.22 t ha(-1) in 2004) gave highest yields, while under less favourable weather conditions two flints ZP 114 (7.45 t ha(-1) in 2001) and ZP 125 (5.40 t ha(-1) in 2003) were most productive. Flint hybrid ZP 115 (7.22 t ha(-1)) was the highest yielding, on average. Also, high average yields were observed in two dent hybrids ZP 290 (7.10 t ha(-1)) and ZP 248 (6.88 t ha(-1)), and one flint ZP 246 (7.09 t ha(-1)). Thus, these four early maize hybrids were characterized as genotypes of high yielding potential. more...

There is a growing trend in production of early maturity maize hybrids as far north and on higher altitudes as possible, even in regions where they were not previously cultivated. Thus, an increased demand at the global market for early maturity maize hybrids of FAO 100 and 200 is present. These hybrids are able to mature under not so favourable temperature conditions. The experiments were performed in Planinica - central part of Serbia at 650 m above sea level, during four years (2001-2004). Nine Zemun Polje (ZP) dent and nine flint hybrids of the FAO 100 and 200 were observed. The highest average grain yield (7.19 t ha(-1)) was recorded in 2002 and it was also high in 2004 was (7.18 t ha(-1)), while in the remaining two years, yields were significantly lower (6.50 t ha(-1) - 2001 and 4.32 t ha(-1) - 2003). In more productive years two dent hybrids: ZP 290 (9.90 t ha(-1) in 2002) and ZP 251 (10.22 t ha(-1) in 2004) gave highest yields, while under less favourable weather conditions two flints ZP 114 (7.45 t ha(-1) in 2001) and ZP 125 (5.40 t ha(-1) in 2003) were most productive. Flint hybrid ZP 115 (7.22 t ha(-1)) was the highest yielding, on average. Also, high average yields were observed in two dent hybrids ZP 290 (7.10 t ha(-1)) and ZP 248 (6.88 t ha(-1)), and one flint ZP 246 (7.09 t ha(-1)). Thus, these four early maize hybrids were characterized as genotypes of high yielding potential. more...

[EN] Identification of the individuals represented in a fragmentary fossil assemblage is a key step in paleobiological research, as ensuing organism-level studies, as well as sampling strategies (e.g., DNA, isotopes, dating, etc.), may depend on the reliability of such estimates. In the human fossil record, dental remains represent the most abundant and informative material, allowing individual identification on the basis of a variety of diagnostic criteria. In this paper, we present a procedure for sequential association of the dental remains and the identification of the minimum number of individuals (MNI) represented in the 49,000-year-old Neandertal assemblage from El Sidrón (Asturias, Spain). In order to quantify the possible association errors, the 12 criteria used in this study are organised according to three levels of reliability. Following this procedure, a minimum of 13 individuals (seven adults, three adolescents, two juveniles and one infant) have been identified at El Sidrón, two of them uniquely represented by postcranial elements. A next step in this investigation foresees the development of methods for associating postcranial elements with the dentally-based identified individuals. © 2013 Académie des sciences., [FR] L’identification du nombre d’individus représentés dans un assemblage fossile fragmentaire est une étape clé dans les recherches paléobiologiques, étant donné que les études postérieures à l’échelle de l’organisme, mais aussi les stratégies d’échantillonnage (ex., ADN, isotopes, datations, etc.) peuvent dépendre de la fiabilité de ces estimations. Dans le registre humain fossile, les restes dentaires représentent le matériel le plus abondant et informatif pour l’identification des individus sur la base d’une variété de critères diagnostiques. Dans cet article, nous présentons une procédure pour l’association séquentielle d’éléments dentaires et l’identification du nombre minimal d’individus (MNI) représentés dans l’assemblage des restes néandertaliens d’El Sidrón (Asturies, Espagne), daté de 49 000 ans. Pour sécuriser les associations dentaires et identifier les erreurs possibles, les 12 critères utilisés dans cette étude ont été répartis selon trois niveaux de fiabilité. D’après cette procédure analytique, un nombre minimal de 13 individus (sept adultes, trois adolescents, deux juvéniles et un enfant) a été identifié à El Sidrón, deux d’entre eux étant uniquement représentés par des éléments postcrâniens. Une étape succédant à cette phase analytique prévoit le développement des méthodes pour l’attribution d’éléments postcrâniens à des individus identifiés uniquement par des associations dentaires. more...

La fluoration de l’eau potable fut introduite pour la première fois aux États-Unis en 1945 afin de prévenir la carie dentaire et fut ensuite rapidement instaurée à plus grande échelle. Aujourd’hui, une majorité d’Américains ont accès à une eau potable fluorée et la situation est similaire au Canada anglais. Au Québec, durant les années 80, par souci de prévention au niveau de l’innocuité pour la santé, les autorités ont instauré un moratoire sur la fluoration de l’eau potable pour éviter d’exposer la population à de trop grandes quantités de fluorures. Il en résulte que seulement trois pour cent des Québécois sont desservis par une eau fluorée. Un débat entre les militants favorables et défavorables existe depuis l’introduction de la fluoration. Il persiste à ce jour à cause de nouvelles données scientifiques suggérant la possibilité d’effets néfastes des fluorures sur la santé. L’objectif principal du présent ouvrage est d’expliciter la problématique écotoxicologique actualisée des fluorures dans les eaux municipales et quelques pistes de solutions. La toxicocinétique et la toxicodynamique des fluorures sont décrites. Lorsqu’ils sont absorbés en trop grande quantité, les fluorures peuvent avoir des effets néfastes sur la santé. Les individus peuvent alors développer une fluorose dentaire, une fluorose osseuse et d’autres maladies (ostéosarcome, problèmes de thyroïde et (ou) de reins, diminution de la tolérance au glucose, affectations cérébrales, altération du métabolisme aérobie de l’ATP, cancer, etc.). Une revue de l’historique de la fluoration des eaux potables et de l’exposition globale aux fluorures ainsi qu’une clarification des faits entourant la carie dentaire ont permis de réaliser que la situation d’aujourd’hui diffère grandement de celle de l’époque où la fluoration a été introduite. Une variété de mesures de prévention de la carie dentaire existe maintenant, à savoir des dentifrices fluorés, des rince-bouches fluorés, des applications de scellants et de more...

Consultable des del TDX, Títol obtingut de la portada digitalitzada, La presente investigación analiza desde el punto de vista bioantropológico los caracteres o rasgos dentales no-métricos de ocho series arqueológicas de dos áreas geográficas diferentes y varios periodos históricos relevantes, que comprenden una cronología que va desde el Epipaleolítico (11.460 ± 230 BP) hasta los siglos XVI-XVII de nuestra era. Si se toman en cuenta las diferentes etapas temporales y el estudio de los dientes pertenecientes a las diferentes series esqueléticas, se podrá conocer el grado de afinidad biológica entre las diferentes poblaciones que habitaron la isla de Mallorca y el levante catalán, así como la evolución o dinámica poblacional de las sociedades humanas de esta parte del Mediterráneo Occidental. Esta es una investigación cuantitativa-descriptiva, de diseño retrospectivo. Tiene como objetivos: 1) Estudiar los rasgos dentales no-métricos para determinar el posible origen de las poblaciones originarias de Mallorca y sus posibles afinidades biológicas con otras poblaciones del área mediterránea, 2) caracterizar morfológicamente a través del estudio de los rasgos dentales no-métricos las series esqueléticas encontradas en la isla de Mallorca y en Cataluña, 3) determinar los rasgos dentales característicos de estas poblaciones. El material del presente estudio proviene de excavaciones arqueológicas realizadas en diferentes campañas a lo largo de los últimos 60 años en dos áreas geográficas relativamente cercanas como son: la Isla de Mallorca (Archipiélago Balear) y Cataluña (Península Ibérica). La muestra está constituida por 618 individuos, de quienes se obtuvieron un total de 11.053 dientes. La metodología del estudio consiste en el análisis morfológico de los dientes a partir del método ASUDAS, reconocido a nivel internacional y utilizado ampliamente en los estudios poblacionales. Los datos fueron procesados y analizados empleando técnicas estadísticas propias de los estudios bioantropológicos. Los resultados se presentan en tres partes: la, A bio-anthropological approach to dental characterisitics from eight digs in two geographical areas through several historical periods. These findings do not attempt strict measurement. The time period covered is from the Epipaleolithic (11,460 ± 230 BP) through the 16th and 17th Centuries A.D. Taking into consideration the varying historical periods and the groups of skeletons, a degree of biological affinity can be determined between the different peoples who inhabited the Island of Mallorca and the Catalalonian Levant on the north-eastern Spanish coast. Variations in the population can also be assessed using this approach. Findings are quantitative only in a generally descriptive historical sense. Objectives include: 1) the examination of non-measured dental traces to determine possible origins of Mallorcan inhabitants and their relation to other groups in the region, 2) the drawing of morphological distinctions specific to the forementioned dental traces of skeletal groups found in the region, 3) general classification of dentition typical of the population groups. Data from digs over the past 60 years were obtained from two areas: Mallorca (Balear Archipelago) and Catalu-a on the adjacent Spanish coast. Samples were taken from 618 individuals, with a total of 11,053 teeth taken. Morphological analysis was performed according to the internationally recognized ASUDAS method used in the study of regional populations. Data was processed and analyzed using bio-anthropological statistics. Findings are presented in three parts: the first is concerned with preliminary analysis including the characteristics of the samples as well as possible errors made by the individual observers themselves in regard to these observations. There are also apparent errors apparent in the course of observer communication. This same first part also includes correlation of dental traces with sexual dimorphics. The second part analyzes the groupings which are being studied and includes degre more...

A Lower and basal Middle varcus Zone (Givetian, Middle Devonian) vertebrate association consisting of chondrichtyan teeth and scales of the genus Phoebodus is documented for the first time from the Aragonian Pyrenees of Spain. This record suggests that different teeth morphologies that were previously treated as separate taxa could be grouped in Phoebodus fastigatus. Moreover, the teeth and scales association is in agreement with the previously reconstructed squamation pattern of this taxon., Un assemblage de microrestes de vertébrés, constitué de dents et écailles du Chondrichthyen Phoebodus, est publié pour la première fois dans les zones inférieure et moyenne à varcus (Givétien, Dévonien moyen) des Pyrénées aragonaises (Espagne). Cet assemblage suggère que des morphologies dentaires différentes qui étaient attribuées jus-qu’à présent à des taxons distincts peuvent être regroupées au sein de Phoebodus fastigatus. De plus, cet assemblage de dents et écailles est conforme à la reconstitution de la squamation qui avait été proposée auparavant pour cette espèce., Dirección General de Investigación Científica y Técnica, Depto. de Geodinámica, Estratigrafía y Paleontología, Fac. de Ciencias Geológicas, TRUE, pub more...

A Lower and basal Middle varcus Zone (Givetian, Middle Devonian) vertebrate association consisting of chondrichtyan teeth and scales of the genus Phoebodus is documented for the first time from the Aragonian Pyrenees of Spain. This record suggests that different teeth morphologies that were previously treated as separate taxa could be grouped in Phoebodus fastigatus. Moreover, the teeth and scales association is in agreement with the previously reconstructed squamation pattern of this taxon., Un assemblage de microrestes de vertébrés, constitué de dents et écailles du Chondrichthyen Phoebodus, est publié pour la première fois dans les zones inférieure et moyenne à varcus (Givétien, Dévonien moyen) des Pyrénées aragonaises (Espagne). Cet assemblage suggère que des morphologies dentaires différentes qui étaient attribuées jus-qu’à présent à des taxons distincts peuvent être regroupées au sein de Phoebodus fastigatus. De plus, cet assemblage de dents et écailles est conforme à la reconstitution de la squamation qui avait été proposée auparavant pour cette espèce., Dirección General de Investigación Científica y Técnica, Depto. de Geodinámica, Estratigrafía y Paleontología, Fac. de Ciencias Geológicas, TRUE, pub more...

The main motivation for this thesis study is that significant workload for aging transport aircrafts is related to dent removal from fuselages. This thesis is a preliminary investigation of aircraft fuselage dents using the Finite Element Method (FEM) via FEA ABAQUS software. We investigated single impact dent on fuselage panel at various locations and impact speeds. The material used for our finite element models is Aluminum Alloy 2024-T3, a typical material used for fuselages of older transport aircrafts. Our finite element model consisted of impact analysis, buckling prediction analysis, and post buckling analysis successively. These analyses were performed on both stiffened and unstiffened aluminum panels. We found that, depending on dent status in aluminum panel, the dent may increase or decrease buckling load of the panel compared to that of the virgin panel (undented). The buckling load of panel with low velocity impact is generally lower than that of the virgin plate. As the impact velocity is increased, buckling load of dented panel increases exceeding buckling load of virgin plate. In addition, we also noticed an existence of critical impact velocity at which the buckling load of the dented panel reached maximum and after which will start to decrease. more...

Collection : Découverte benjamin ; 29, Collection : Découverte benjamin ; 29, Appartient à l’ensemble documentaire : UnivJeun0, Contient une table des matières, Avec mode texte, Ouvrages pour la jeunesse more...

Collection : Découverte benjamin ; 29, Collection : Découverte benjamin ; 29, Appartient à l’ensemble documentaire : UnivJeun0, Contient une table des matières, Avec mode texte, Ouvrages pour la jeunesse more...

[EN] Isolated Dinosaur teeth have been discovered in the Upper Triassic locality of Habay-la-Vieille, in southern Belgium. Ornithischia are represented by three dental morphotypes; two of them closely resemble isolated teeth from the Middle or Upper Jurassic of Portugal and England. The presence of sauropods in the Upper Triassic of Europe is confirmed. Sauropods already had a wide geographical distribution during the Latest Triassic, as fossils have been discovered in South Africa, Thailand and western Europe. At Habay-la-Vieille, sauropods and prosauropods co-existed at the end of the Triassic. Two dental morphotypes may tentatively be referred to as theropod dinosaurs. The study of isolated teeth indicates that dinosaurs were already well diversified in the Latest Triassic of western Europe., [FR] Des dents isolées de dinosaures ont été découvertes dans les Trias supérieur d’Habay-la-Vieille, en Lorraine belge. Les Ornithischia sont représentés par trois morphotypes, dont deux semblent très proches de dents isolées découvertes dans le Jurassique moyen à supérieur du Portugal et d’Angleterre. La présence de sauropodes dans le Trias supérieur d’Europe est confirmée. Les sauropodes occupaient déjà une aire de répartition géographique étendue au cours du Trias terminal, puisque des ossements ont été découverts en Afrique du Sud, en Thaïlande et en Europe occidentale. Des sauropodes et des prosauropodes ont coexisté à Habay-la-Vieille à la fin du Trias. Deux morphotypes dentaires peuvent prudemment être attribués à des dinosaures théropodes. L’étude des dents isolées montre que les dinosaures étaient déjà bien diversifiés en Europe occidentale à la fin du Trias. more...

This paper presents the experimental test and the results of the development of a composite organic material (MCO) for the reinforcement and covering of pipelines. MCO is desinged to be applied to pipelines with external, damages such as dents or gauges or with surface damages caused by corrosion. The product can recover transport lines with 65% thickness losses due to corrosion in lenghts of less than 0,2 m. The system developed by Ecopetrol-ICP can stop progressive picking corrosion, it has an excellent capillary, good adhesion, good resistance in cathodic protection, and mechanical strength that can support the operational pressure of the pipeline. MCO is a mixture of a polymeric resin reinforced with organic fibers, it can be applied to surface or underground pipelines without stopping normal operation. The maximum rupture pressure attained by the MCO was 23,4 MPa in pipelines with a 65% tickness loss due to corrosion. The normal operation pressure is 1 0 - 1 2 MPa., En este documento se presentan las pruebas experimentales, y sus resultados, realizadas durante el diseño y desarrollo de un Material Compuesto Orgánico (MCO) para refuerzo y recubrimiento de tuberías de transporte de fluidos. El MCO se diseña para ser utilizado en oleoductos que presenten daños superficiales externos tipo abolladuras o picado por corrosión. El MCO puede recuperar líneas de transporte con defectos del 65% de pérdida de espesor por corrosión en longitudes no mayores a 0,2 m (es posible reforzar defectos de mayor profundidad, pero en menores longitudes). El sistema desarrollado por Ecopetrol-ICP, tiene la particularidad de detener el avance de la corrosión, posee excelente capilaridad, buena adhesión, buena resistencia en protección catódica y buena resistencia mecánica, suficiente para la presión de operación de un oleoducto. El MCO consiste en una matriz polimérica (resinas epóxicas) reforzada con fibras orgánicas. Una ventaja que da a este producto una alta competitividad es su bajo peso, muy apropiado para ciertas aplicaciones donde éste es un factor problema. Finalmente, el sistema puede ser aplicado tanto en tuberías enterradas como sobre superficie, sin necesidad de suspender la operación. La presión de ruptura máxima alcanzada por el MCO es de 23,4 MPa (instalado en tuberías con defectos de pérdida de espesor por corrosión del 65%), comparativamente la presión de operación normal de un oleoducto no supera los 1 0 ó 12 MPa. more...

This paper presents the experimental test and the results of the development of a composite organic material (MCO) for the reinforcement and covering of pipelines. MCO is desinged to be applied to pipelines with external, damages such as dents or gauges or with surface damages caused by corrosion. The product can recover transport lines with 65% thickness losses due to corrosion in lenghts of less than 0,2 m. The system developed by Ecopetrol-ICP can stop progressive picking corrosion, it has an excellent capillary, good adhesion, good resistance in cathodic protection, and mechanical strength that can support the operational pressure of the pipeline. MCO is a mixture of a polymeric resin reinforced with organic fibers, it can be applied to surface or underground pipelines without stopping normal operation. The maximum rupture pressure attained by the MCO was 23,4 MPa in pipelines with a 65% tickness loss due to corrosion. The normal operation pressure is 1 0 - 1 2 MPa., En este documento se presentan las pruebas experimentales, y sus resultados, realizadas durante el diseño y desarrollo de un Material Compuesto Orgánico (MCO) para refuerzo y recubrimiento de tuberías de transporte de fluidos. El MCO se diseña para ser utilizado en oleoductos que presenten daños superficiales externos tipo abolladuras o picado por corrosión. El MCO puede recuperar líneas de transporte con defectos del 65% de pérdida de espesor por corrosión en longitudes no mayores a 0,2 m (es posible reforzar defectos de mayor profundidad, pero en menores longitudes). El sistema desarrollado por Ecopetrol-ICP, tiene la particularidad de detener el avance de la corrosión, posee excelente capilaridad, buena adhesión, buena resistencia en protección catódica y buena resistencia mecánica, suficiente para la presión de operación de un oleoducto. El MCO consiste en una matriz polimérica (resinas epóxicas) reforzada con fibras orgánicas. Una ventaja que da a este producto una alta competitividad es su bajo peso, muy apropiado para ciertas aplicaciones donde éste es un factor problema. Finalmente, el sistema puede ser aplicado tanto en tuberías enterradas como sobre superficie, sin necesidad de suspender la operación. La presión de ruptura máxima alcanzada por el MCO es de 23,4 MPa (instalado en tuberías con defectos de pérdida de espesor por corrosión del 65%), comparativamente la presión de operación normal de un oleoducto no supera los 1 0 ó 12 MPa. more...

This paper presents the broad experience obtained in the Caño Limón Coveñas pipeline (OCLC), located in Colombia, on the manipulation and evaluation of the dents caused by explosive charges. During the last ten years, the OCLC pipeline has suffered more than 450 terrorist attacks using explosive charges. Most of the damages do not cause the total rupture of the pipes, they only generate dents and distortions grater than five percent (5%). A as consequence of this situation, we have tried to acquire all the judgement elements required to choose the appropriate time to change the pipes an to know the pressure level for a continuos and safe operation of the pipeline. The study include some three main aspects: (a) Characterization of the dents considering their geometry, materials (hardness, metallographic structure, efforts, etc) influences of explosive charges and of the operation pressure as well as hydrostatic pressure tests overa real scale pipe, (b) Creation and validation of a new method for dent evaluation and (c) Discussion of the analysis through numeric modeling. Results show an increase in the elastic and rupture resistance of the material located in the target area and therefore, a subsequuent fatigue resistance decrease. Fatigue is the possible cause for the subsequent rupture of the pipeline once it has been dented by an explosive charge. The hidrostatic tests have shown that a partial shape recovery is obtained when the pipeline undergoes a high operational pressure. For a 24% dent there will be 0.036 m recovery at a 1 2.4 Mpa pressure., Se registra en este artículo la amplia experiencia obtenida en el oleoducto Caño Limón Coveñas, OCLC, Colombia, sobre el manejo y evaluación de las abolladuras causadas en la tubería por cargas explosivas. El OCLC ha sido sometido a más de 450 atentados terroristas con cargas explosivas. La mayoría de estos daños no llegan a la ruptura total de la tubería sino que generan deformaciones o abolladuras permanentes, mayores al 5%. Por lo tanto, se trata de adquirir elementos de juicio para la toma de decisiones sobre cuándo cambiarla y a su vez conocer el rango de presión en el cual puede operar el oleoducto de manera continua y segura. En el estudio se consideran varios aspectos relacionados con la evaluación de las abolladuras. Estos son: (a) La caracterización de las abolladuras en cuanto a la geometría, materiales (dureza, estructura metalográfica y esfuerzos, entre otros), efectos de las cargas explosivas y de la presión de operación y pruebas de presión hidrostática en tuberías a escala real, (b) La creación y validación de un nuevo procedimiento para evaluarlas abolladuras, (c) Discusión del análisis con modelamiento numérico. Los resultados muestran un aumento en la resistencia elástica y de ruptura del material localizada en la zona afectada y, por lo tanto, una disminución de la resistencia a la fatiga. Esta última es posiblemente la causa de la ruptura posterior de la tubería una vez ha sido abollada por la carga explosiva. Las pruebas hidrostáticas han demostrado que la tubería, al ser sometida a la presión interna de operación, sufre una recuperación parcial de su forma. En el caso de una abolladura tipo 24%, a presión de 1 2,4 MPa, se recuperará 0,036 m. more...

This paper presents the broad experience obtained in the Caño Limón Coveñas pipeline (OCLC), located in Colombia, on the manipulation and evaluation of the dents caused by explosive charges. During the last ten years, the OCLC pipeline has suffered more than 450 terrorist attacks using explosive charges. Most of the damages do not cause the total rupture of the pipes, they only generate dents and distortions grater than five percent (5%). A as consequence of this situation, we have tried to acquire all the judgement elements required to choose the appropriate time to change the pipes an to know the pressure level for a continuos and safe operation of the pipeline. The study include some three main aspects: (a) Characterization of the dents considering their geometry, materials (hardness, metallographic structure, efforts, etc) influences of explosive charges and of the operation pressure as well as hydrostatic pressure tests overa real scale pipe, (b) Creation and validation of a new method for dent evaluation and (c) Discussion of the analysis through numeric modeling. Results show an increase in the elastic and rupture resistance of the material located in the target area and therefore, a subsequuent fatigue resistance decrease. Fatigue is the possible cause for the subsequent rupture of the pipeline once it has been dented by an explosive charge. The hidrostatic tests have shown that a partial shape recovery is obtained when the pipeline undergoes a high operational pressure. For a 24% dent there will be 0.036 m recovery at a 1 2.4 Mpa pressure., Se registra en este artículo la amplia experiencia obtenida en el oleoducto Caño Limón Coveñas, OCLC, Colombia, sobre el manejo y evaluación de las abolladuras causadas en la tubería por cargas explosivas. El OCLC ha sido sometido a más de 450 atentados terroristas con cargas explosivas. La mayoría de estos daños no llegan a la ruptura total de la tubería sino que generan deformaciones o abolladuras permanentes, mayores al 5%. Por lo tanto, se trata de adquirir elementos de juicio para la toma de decisiones sobre cuándo cambiarla y a su vez conocer el rango de presión en el cual puede operar el oleoducto de manera continua y segura. En el estudio se consideran varios aspectos relacionados con la evaluación de las abolladuras. Estos son: (a) La caracterización de las abolladuras en cuanto a la geometría, materiales (dureza, estructura metalográfica y esfuerzos, entre otros), efectos de las cargas explosivas y de la presión de operación y pruebas de presión hidrostática en tuberías a escala real, (b) La creación y validación de un nuevo procedimiento para evaluarlas abolladuras, (c) Discusión del análisis con modelamiento numérico. Los resultados muestran un aumento en la resistencia elástica y de ruptura del material localizada en la zona afectada y, por lo tanto, una disminución de la resistencia a la fatiga. Esta última es posiblemente la causa de la ruptura posterior de la tubería una vez ha sido abollada por la carga explosiva. Las pruebas hidrostáticas han demostrado que la tubería, al ser sometida a la presión interna de operación, sufre una recuperación parcial de su forma. En el caso de una abolladura tipo 24%, a presión de 1 2,4 MPa, se recuperará 0,036 m. more...

ARALL(R) laminates are the first generation of a new class of materials combining the best properties of metals and composite materials. This report represents part of a Phase I of a two phase study of ARALL(R) -I laminates. Ten specimens were tested in a modified Boeing Compression-After- Impact fixture. Two specimens were undamaged. The remaining eight received impacts of 2.3 ft-lbs (3.18J), 5.5 ft-lbs (7.5J), 10.4 ft-lbs (14. lJ), and 11.7 ft-lbs (15.9J). Only dents were produced at 2.3 ft-lbs (3.18J). Back face cracks appeared at 5.5 ft-lbs (7.5J). Full penetration was achieved at 10.4 ft-lbs (14. lJ). Interior damage as measured by ultrasonic 'C' scan showed little damage beyond that already visible on the Surface. Compressive buckling was the mode of failure. Increasing impact energy decreased the buckling load of the specimens. 'C' scans taken after compression testing revealed no growth of the interior damage. more...

Bibliogr. p. 183-189. Index

Ouvrages avant 1800

Ouvrages avant 1800

Contient une table des matières, Avec mode texte, Ouvrages avant 1800

Contient une table des matières, Avec mode texte, Ouvrages avant 1800

Comprend : Page de titre [Cote :14040] ; Carte p.161 = Carte de la chaîne des montagnes de Langres / Aldring grav. [Cote :14041,A] ; pl.1 p.512 dépliante = [dents] / Chevillet grav. [Cote :14042,A] ; pl.2 p.512 dépliante = [dents] / Chevillet grav. [Cote :14043,A] ; pl.3 p.512 dépliante = [dents] / Chevillet grav. [Cote :14044,A] ; pl.4 p.512 dépliante = [dents] / Pasch grav. [Cote :14045,A] ; pl.5 p.512 dépliante = [dents d' hippopotame] / Chevillet grav. [Cote :14046,A] ; pl.6 p.512 dépliante = [dents] / Chevillet grav. [Cote :14047,A] ; Carte p.616 dépliante = carte des deux régions polaires jusqu'au 45 degré de latitude / Aldring grav. [Cote :14048,A], Thème : Sciences de la nature, Cartes -- +* 1700......- 1799......+:18e siècle, Illustration more...

Contient une table des matières