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Habib, Baher. "Relations entre karstification, cadre morphostructural et incisions des vallées dans les calcaires du Dogger en Haute-Saône (plateaux de Vesoul et de Combeaufontaine)." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0223.
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Les calcaires du Dogger des plateaux de Vesoul et de Combeaufontaine, qui se situent sur les bordures nord du Fossé bressan, sont parmi les plus karstifiés de Haute Saône. Les plateaux de Vesoul et de Combeaufontaine, dépourvus le plus souvent d’écoulements superficiels, possèdent de très nombreuses formes karstiques (dolines, dépressions fermées de dimensions hectométriques, pertes, grottes, gouffres) inscrites dans les 5 formations calcaires du Dogger : Calcaires à entroques, Calcaires à polypiers, Grande Oolithe (Bajocien), Calcaires compacts (Bathonien) et Dalle nacrée (Callovien inférieur). Parmi ces formes, les dolines, de dimensions pluridécamétriques, sont les plus nombreuses et sont représentées surtout par des dolines dissymétriques localisées surtout dans les vallées sèches souvent perchées au-dessus des vallées principales. Sous les deux plateaux, les circulations des eaux souterraines s’effectuent dans de vastes réseaux de galeries en partie noyées, pouvant atteindre 9 km (Deujeau) et participent à une réorganisation de drainage vers le Fossé de la Saône. L’essentiel du karst est un karst infra-talweg développé en lien avec l’intense fracturation des calcaires du Dogger, qui correspond à l’amont, aux pertes inscrites dans les percées cataclinales des bordures nord des deux plateaux, aux phénomènes karstiques situés dans les vallées sèches et aux circulations souterraines sous les vallées, ainsi qu’aux sources souvent abondantes Font de Champdamoy), situées dans les vallées des bordures méridionales des plateaux et de la bordure occidentale du plateau de Vesoul. Les galeries souterraines sont orientées le long de directions N10° à N40°, conformes à la fracturation régionale ou perpendiculaires à cette direction pour les réseaux se développant par érosion régressive à partir de la bordure ouest du plateau de Vesoul. Le karst infra-talweg concerne au moins en partie aussi les cavités perchées, façonnées en relation avec l’incision des vallées, comme la grotte des Equevillons (+113 m) façonnée en régime noyé. Le karst de contact lithostratigraphique est particulièrement discret sur le plateau de Vesoul en raison de la faible épaisseur des marnes du Callovo-Oxfordien recouvrant la Dalle nacrée (< 50 m). L’ancienneté de la karstification, attestée par l’existence de galeries perchées jusqu’à près de 350 m d’altitude absolue, est confortée par la longueur des galeries souterraines (10% > à 2 km), les dimensions des salles, ou de celles des dépressions fermées hectométriques drainées vers l’endokarst. Les cavités les plus anciennes pourrait remonter au début du Quaternaire, lorsque le soulèvement régional lié aux mouvements jurassiens a entraîné une incision les long des vallées de la Saône et de l’Ognon d’environ 50 m. De cette période, daterait le décapage des altérites ferrugineuses sur les plateaux et leur piégeage dans plusieurs grottes, comme celle des Equevillons. L’intense karstification des calcaires du Dogger, liée à leur fracturation, rattachent davantage les formes des plateaux de Vesoul et de Combeaufontaine à celles d’un karst jurassien, plutôt qu’à celles des plateaux de mêmes altitudes de l’Est du Bassin parisienThe Dogger Limestones of the plateaus of Vesoul and Combeaufontaine, which are located in the northern margin of the Bresse graben, are one of the most karstified areas of Haute-Saône Department. These plateaus don’t have active superficial flows. They have numerous karstic forms (sinkholes, forest hollows and closed depressions of hectometric dimensions, interrupted flows, caves, vertical shafts) in the 5 limestones formations of the Middle Jurassic (Dogger) : “Calcaires à entroques”, “Calcaires à polypiers”, “Grande Oolithe” (Bajocian), “Calcaires compacts” (Bathonian) et “Dalle nacrée” (Lower Callovian). The most numerous exokarstic forms are the multidecametric asymmetrical sinkholes, located on sections of dry valleys above the main valleys. Under the both plateaus, the subterranean waters flow in a vast networks of galleries, which could reach 9 km (Deujeau) and participate in a reorganization of drainage towards the graben of the Saône. The main part of the karst is an infra-talweg karst, which is developed in connection with the greatly fractured Dogger limestones. Its corresponds, upstreams, to the sinkholes of the consequent valleys located on the Dogger cuesta on the Northern borders of the both plateaus, under these plateaus, to the karstic active forms situated in dry valleys and to the subterranean circulations, and, on the Southern borders of these plateaus and the western border of the plateau of Vesoul to abundant emergences (Font of Champdamoy) situated in the main valleys. The subterranean galleries are oriented towards the N10° to N40° directions, in accordance with the regional faults or perpendicularly to these directions due to regressive erosion of the rivers from the Western border of the plateau of Vesoul. The infra-talweg karst also concerns high cavities, shaped in connection with valleys incision, as the cave of Equevillons (113 m) which has been shaped under conditions of drowned palaeovalleys. The forms of the lithostratigraphic karst is particularly not very numerous on the Vesoul plateau due to the low thickness of the Callovo-Oxfordian marls located on the « Dalle nacrée » formation (50 m deepth). The old age of the karstification is attested by the presence of karstic galleries until about 350 m ASL of absolute height, by the galleries lengths (10 % > 2 km), the sizes of the caves, or the presence of hectometric closed karstic depressions drained towards the endokarst. The most ancient cavities could be attributed to the beginning of the Quaternary Period, when a regional uplift occured in connection with the Jura tectonic movements and cause a general incision reaching 50 m deepth along the Saône and the lower Ognon valleys. The erosion of the ferruginous weathering profiles of the plateaus and the trapping of weathered sediments in caves (e.g. Equevillons) may be dated to this period. The intense karstification of the fractured Dogger limestones is closer to the forms of the Jura karst, rather than those of the Eastern Paris Basin, which is present at similar altitudes
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MALIN, LAURENCE. "Les modalites de sortie des personnes agees apres une hospitalisation en court sejour : etude prospective de 581 dossiers au centre hospitalier de vesoul (haute-saone)." Besançon, 1992. http://www.theses.fr/1992BESA3104.
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TRAN, TUAN-ANH. "A la recherche du profil predictif du suicidant selon les periodes de la vie : a propos de 364 observations recueillies au c.h. vesoul en 2 ans (1988-1989)." Besançon, 1990. http://www.theses.fr/1990BESA3094.
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Fizaine, Jean-Paul. "Les paléokarsts et les formations ferrugineuses associées dans le Bassin Parisien et ses bordures : caractérisations et évolutions géomorphologiques." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0179/document.
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Sur les bordures du Bassin parisien et leurs périphéries, plus particulièrement sur lessubstrats jurassiques et crétacés, on trouve des paléokarsts fossilisés par des dépôtsferrugineux.Plus de 60 sites aériens ou souterrains ont été étudiés au Sud de l'Ardenne, de laThiérache ardennaise au Pays-Haut ; sur le contact Jurassique-Crétacé aux confins de laLorraine et de la Champagne (Vallage, Barrois et Haut-Pays) ; au Nord du Massif Central,de la Champagne berrichonne au Montmorillonnais ; sur les plateaux crayeux deNormandie, du Pays d'Ouche et de la Plaine de Saint-André ; à la charnière entre Riftsbressan et rhénan (fossé de la petite Saône, plateaux de Vesoul, Collines préjurassiennes).Les analyses de près de 250 échantillons (macroscopie et microscopie, granulométrie etmorphoscopie, analyses chimiques et minéralogiques), ont montré que ces ferricrètesprésentent des faciès extrêmement variés tant sur le plan de la structure que sur ceux dela forme ou de la taille. Ces faciès peuvent résulter, soit d'un remaniement mécaniquedominant, soit d'un remaniement chimique dominant voire exclusif, ou encore alliant desremaniements à la fois mécaniques et chimiques.Les dépôts ferrugineux issus à l'origine de ferricrètes générées lors de grandes périodesd'altération ferralitiques qui ont affecté l'Europe occidentale entre le Crétacé inférieur et ledébut du Tertiaire ont évolué au gré de l'encaissement des vallées au Plio-Quaternaire.Par conséquent le karst est générateur de faciès spécifiques et contribue à amplifier lesprocessus de remaniement chimique ou mécaniqueThat's on the board of the Parisian Basin and its surrounding, and more particularly on theJurassic as well as the cretaceous subterrane, we can find some paleokarsts fossilized.More of 60 underground or aerial sites have been studied in the South of the Ardenne,from the Thiérache ardennaise to the Pays-Haut ; on the contact of the Jurassic-Cretaceous to the limits of the Lorraine and the Champagne (Vallage, Barrois and Haut-Pays) ; to the North of the Massif Central, from the Champagne berrichonne to theMontmorillonnais ; on the chalky trays of Normandy (Pays d?Ouche, Plaine de Saint-André) ; at the hinge between bressan and rhenan Graben (fossé de la petite Saône,Plateaux de Vesoul, Collines pré-jurassiennes).Analyses made on 250 samples (macroscopic and microscopic analysis, granulometryand morphoscopy, mineralogical and chemical analyses), have shown that these ironcementation present facies extremely varied on both structure and size. These facies canresult, either in a dominant mechanical revision, or in a chemical revision dominatingperhaps exclusive, or in allying both chemical or mechanical reworking.The stemming ferruginous deposits coming from the ferricrusts generated during theperiods of ferralitic alteration having affected the Western Europe between the inferiorCretaceous and the beginning of the Tertiary, have evolved according to the collection ofvalleys during the Plio-Quaternary. Consequently the karst is generator of specific faciesand contributes to amplify chemical or mechanical revision processes
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Blondel-Gaborieau, Celia. "La transmission du patrimoine culturel immatériel à l'école primaire : le cas du projet choral scolaire "Les Voix de la mémoire"." Thesis, Bourgogne Franche-Comté, 2018. http://www.theses.fr/2018UBFCC017/document.
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Ce travail se propose, au travers d’une recherche-action qui a concerné quinze classes de l’agglomération vésulienne, de mener une réflexion sur les enjeux d’un projet choral commémoratif. Il interroge le lien entre mémoire et transmission du patrimoine culturel immatériel, et rend compte de ce que peuvent être des enseignements de ce type à l’école aujourd’hui.L’année 2014 a été marquée par le centenaire de la Première Guerre mondiale et les soixante-dix ans de la Libération. C’est dans ce contexte que le projet « Les Voix de la mémoire » a été mis en œuvre par la Direction des Services départementaux de l’Éducation nationale de la Haute-Saône, en partenariat avec de nombreux acteurs de ce territoire. Plus de trois cents enfants ont travaillé une année avec des professionnels de la musique sur des chants historiques, traditionnels et contemporains qui disent la guerre et la paix. Ce projet s’est conclu par une représentation sur une scène conventionnée face à un très large public composé notamment de leurs familles et d’officiels.Par des questionnaires, des entretiens et des observations, cette contribution croise de nombreux regards. Les enseignants, une inspectrice, les familles et les élèves parlent de ce qui a pris place dans le cadre scolaire. L’enfant est considéré comme acteur de ce qu’on lui fait vivre. Une méthodologie spécifique est développée pour recueillir sa parole qui est écoutée et valorisée. Lesapprentissages, les joies et les difficultés des différents participants sont ici mis en avant et décryptés. Sont évoquées plus particulièrement les émotions générées par le moment de la commémoration comme rite républicainThrough an action research which has involved fifteen classes from the urban district of Vesoul, thispaper aims at questioning the link between remembering and transmitting our intangible culturalheritage, reflecting on the stakes surrounding a memorial choir project, and records what aneducation on such topics can be like today.The year 2014 marked the hundred-year anniversary of the beginning of WWI and theseventy-year anniversary of the WW2 Liberation. In this context, the Direction des Servicesdépartementaux de l’Éducation nationale de la Haute-Saône, along with other contributors of thearea, initiated the project entitled « The Voices of Memory ». Under the instruction of musicprofessionals, over three hundred children practiced historical, traditional and contemporary songs about war and peace, all year long. The project concluded with a performance in a subsidised theatre for an audience including families and officials.This research has aimed at gathering as many viewpoints as possible through itsquestionnaires, interviews and observations. The teachers, one Education Inspector, the families and the pupils all talk of what took place at school. The children are viewed as active participants in the project they are made to take part in. A specific methodology was developed so as to record, listen to and value their words. The joys and hardhips of the learning experience of all involved have been carefully highlighted and decyphered, with careful emphasis on the emotions triggered by the memorial itself, viewed as a rite in honour of the French Republic
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Wolfe, Jeremy Dean. "Vessel Formation and Feeder Vessel Treatment in Choroidal Neovascularization." University of Toledo Health Science Campus / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=mco1095878383.
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Carroll, Alice. "The contemporary vessel /." Online version of thesis, 1992. http://hdl.handle.net/1850/11622.
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Grieff, Stacey. "The Raddled Vessel." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/2958.
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The wearing effects of being overworked and in somewhat poor health are reflected in my paintings, ceramic work, and mixed media pieces. I use old and dilapidated materials such as window frames, instrument cases, and wood to symbolically address my physical and emotional states. I reuse items from the past that show a sense of fatigue, tattered edges, and deterioration. Like these objects I felt run down, old, and at times, useless. However, I am comforted by the idea that old objects can, with some care, regain new life. I have discovered I seek my own rejuvenation through my creativity. As a means of releasing anger and frustration toward my fading health, I create assemblages of wilted flowers, encaustic hourglass forms, and mixed media teapots. I also create clay vessels that appear to be deteriorating and encapsulate objects in encaustic medium. Items that belonged to my relatives serve as a metaphor for my genetic illnesses. Searching for answers, living in the present, and maintaining hope are things I carry with me on my artistic journey to find a sense of self worth and to overcome disease.
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Wyatt, Hayley Louise. "Electrosurgical vessel sealing." Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/59830/.
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Electrosurgical vessel sealing devices have been demonstrated to reduce patient blood loss and operative time during surgery. Whilst the benefits of such devices are widely reported there is still a large variation in the quality of the seal produced, with factors such as vessel size known to effect seal quality. The study aimed to investigate parameters affecting device performance and improve the seal quality. The burst pressure test was used to assess the seal quality and tissue adhesion was measured using a peel test. Additionally histology techniques were used to quantify vessel morphology and found that with an increase in elastin content there was a reduction in seal quality. A number of device modifications were made, testing a selection of non-stick coatings and surface features of the shims. No coating reduced the level of tissue adhesion to the device, but results found that with a greater level of adhesion there was a reduction in seal quality. Considering the different surface features one design, a combination of longitudinal and transverse grooves, resulted in a seal failure rate of 0.0%, a significant improvement in device performance. Two FEM’s were produced to further investigate the device modifications; one in FEBio investigating the mechanical aspects of vessel sealing and the second a multiphysics model to investigate the thermal aspects of vessel sealing. Results from both FEM’s showed a difference in shim performance, with the addition of surface features effecting the stress distribution within the vessel wall and the heat distribution. Additionally DIC was used to capture the vessel sealing process, with results showing each seal was produced in a different way with different levels of tissue contraction. Research conducted demonstrated a number of significant relationships between seal quality and vessel properties, but did not find an explanation for all variation occurring.
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Suwal, Pasang Sherpa. "Passive Acoustic Vessel Localization." PDXScholar, 2012. https://pdxscholar.library.pdx.edu/open_access_etds/757.
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This thesis investigates the development of a low-cost passive acoustic system for localizing moving vessels to monitor areas where human activities such as fishing, snorkeling and poaching are restricted. The system uses several off-the-shelf sensors with unsynchronized clocks where the Time Difference of Arrival (TDOA) or time delay is extracted by cross-correlation of the signal between paired sensors. The cross-correlation function uses phase correlation or Phase Transform (PHAT) which whitens the cross-spectrum in order to de-emphasize dominant frequency components. Using the locations of pairs of sensors as foci, hyperbolic equations can be defined using the time delay between them. With three or more sensors, multiple hyperbolic functions can be calculated which intersect at a unique point: the boat's location. It is also found that increasing separation distances between sensors decreased the correlation between the signals. However larger separation distances have better localization capability than with small distances. Experimental results from the Columbia and Willamette Rivers are presented to demonstrate performance.
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Masterson, Richard Garrett. "Torso as ceramic vessel." PDXScholar, 1990. https://pdxscholar.library.pdx.edu/open_access_etds/4141.
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The ceramic forms in this thesis project represent a study of the sculptural and figurative qualities of the ceramic process. This study includes a search for a personal form language, development of the slab construction technique, and development of a glazed surface appropriate to the work. The subject of the work is the human torso, with the vessel-like forms focusing on the core of the body as a metaphor for the core of the human spirit.
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Kaha, Myra. "The vessel and the sacred." Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4791.
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Thesis (M.F.A.)--West Virginia University, 2006.Title from document title page. Document formatted into pages; contains v, 15 p. : col. ill. Vita. Includes abstract. Includes bibliographical references (p. 13).
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Teng, Thomas Bart. "Vessel identification in diabetic retinopathy." Thesis, Bournemouth University, 2003. http://eprints.bournemouth.ac.uk/441/.
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Diabetic retinopathy is the single largest cause of sight loss and blindness in 18 to 65 year olds. Screening programs for the estimated one to six per- cent of the diabetic population have been demonstrated to be cost and sight saving, howeverthere are insufficient screening resources. Automatic screen-ing systems may help solve this resource short fall. This thesis reports on research into an aspect of automatic grading of diabetic retinopathy; namely the identification of the retinal blood vessels in fundus photographs. It de-velops two vessels segmentation strategies and assess their accuracies. A literature review of retinal vascular segmentation found few results, and indicated a need for further development. The two methods for vessel segmentation were investigated in this thesis are based on mathematical morphology and neural networks. Both methodologies are verified on independently labeled data from two institutions and results are presented that characterisethe trade off betweenthe ability to identify vesseland non-vessels data. These results are based on thirty five images with their retinal vessels labeled. Of these images over half had significant pathology and or image acquisition artifacts. The morphological segmentation used ten images from one dataset for development. The remaining images of this dataset and the entire set of 20 images from the seconddataset were then used to prospectively verify generaliastion. For the neural approach, the imageswere pooled and 26 randomly chosenimageswere usedin training whilst 9 were reserved for prospective validation. Assuming equal importance, or cost, for vessel and non-vessel classifications, the following results were obtained; using mathematical morphology 84% correct classification of vascular and non-vascular pixels was obtained in the first dataset. This increased to 89% correct for the second dataset. Using the pooled data the neural approach achieved 88% correct identification accuracy. The spread of accuracies observed varied. It was highest in the small initial dataset with 16 and 10 percent standard deviation in vascular and non-vascular cases respectively. The lowest variability was observed in the neural classification, with a standard deviation of 5% for both accuracies. The less tangible outcomes of the research raises the issueof the selection and subsequent distribution of the patterns for neural network training. Unfortunately this indication would require further labeling of precisely those cases that were felt to be the most difficult. I.e. the small vessels and border conditions between pathology and the retina. The more concrete, evidence based conclusions,characterise both the neural and the morphological methods over a range of operating points. Many of these operating points are comparable to the few results presented in the literature. The advantage of the author's approach lies in the neural method's consistent as well as accurate vascular classification.
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Zhang, Lei. "Retinal vessel segmentation using textons." Thesis, University of East Anglia, 2014. https://ueaeprints.uea.ac.uk/54401/.
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Segmenting vessels from retinal images, like segmentation in many other medical image domains, is a challenging task, as there is no unified way that can be adopted to extract the vessels accurately. However, it is the most critical stage in automatic assessment of various forms of diseases (e.g. Glaucoma, Age-related macular degeneration, diabetic retinopathy and cardiovascular diseases etc.). Our research aims to investigate retinal image segmentation approaches based on textons as they provide a compact description of texture that can be learnt from a training set. This thesis presents a brief review of those diseases and also includes their current situations, future trends and techniques used for their automatic diagnosis in routine clinical applications. The importance of retinal vessel segmentation is particularly emphasized in such applications. An extensive review of previous work on retinal vessel segmentation and salient texture analysis methods is presented. Five automatic retinal vessel segmentation methods are proposed in this thesis. The first method focuses on addressing the problem of removing pathological anomalies (Drusen, exudates) for retinal vessel segmentation, which have been identified by other researchers as a problem and a common source of error. The results show that the modified method shows some improvement compared to a previously published method. The second novel supervised segmentation method employs textons. We propose a new filter bank (MR11) that includes bar detectors for vascular feature extraction and other kernels to detect edges and photometric variations in the image. The k-means clustering algorithm is adopted for texton generation based on the vessel and non-vessel elements which are identified by ground truth. The third improved supervised method is developed based on the second one, in which textons are generated by k-means clustering and texton maps representing vessels are derived by back projecting pixel clusters onto hand labelled ground truth. A further step is implemented to ensure that the best combinations of textons are represented in the map and subsequently used to identify vessels in the test set. The experimental results on two benchmark datasets show that our proposed method performs well compared to other published work and the results of human experts. A further test of our system on an independent set of optical fundus images verified its consistent performance. The statistical analysis on experimental results also reveals that it is possible to train unified textons for retinal vessel segmentation. In the fourth method a novel scheme using Gabor filter bank for vessel feature extraction is proposed. The ii method is inspired by the human visual system. Machine learning is used to optimize the Gabor filter parameters. The experimental results demonstrate that our method significantly enhances the true positive rate while maintaining a level of specificity that is comparable with other approaches. Finally, we proposed a new unsupervised texton based retinal vessel segmentation method using derivative of SIFT and multi-scale Gabor filers. The lack of sufficient quantities of hand labelled ground truth and the high level of variability in ground truth labels amongst experts provides the motivation for this approach. The evaluation results reveal that our unsupervised segmentation method is comparable with the best other supervised methods and other best state of the art methods.
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Eckerd, K. Richard. "Glass : beyond the archetypal vessel /." Online version of thesis, 1996. http://hdl.handle.net/1850/12204.
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Largiadèr, Caspar Andri 1965. "Vessel valuation : an options approach." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/8991.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1999.Includes bibliographical references (p. 74-75).
In the field of capital budgeting traditionally the widely accepted net-present-value (NPV) technique is used to capture a project's value. However, this approach fails to quantify managerial and operational flexibility and strategic interactions. The underlying analysis deals with the subject of resource allocation or capital budgeting under uncertainty, particularly with the valuation of managerial and operating flexibility as real options. Similar to options on financial assets, real options involve decisions or rights, with no obligation, to acquire or exchange an asset or project for a pre-specified price. Within the shipping industry the application of real options on operating vessels as strategic decision tools has so far been more or less neglected, since only few players are familiar with the option theory. A charterer operating a vessel may have an agreement with the owner to acquire the ship at some future date, giving him the option, without obligation, to do so. This flexibility to undertake a vessel acquisition provides the charterer with a certain value, depending on the movements of the market. This paper initially introduces the general option pricing theory applied to financial securities. Furthermore, an alternative way of modeling the stochastic nature of time charter. equivalent spot rates for the bulk freight market is presented. It is proposed to abandon the Geometric Brownian motion and, instead, to apply a mean reverting process, such as the OmsteinUhlenbeck process, to replicate the freight rates. Based on these findings, closed form option valuation tools are applied to a Panamax vessel type for one specific route, capturing the mean reverting character of the ship's cash flows. The results of the option valuation are discussed considering their practicability. Finally, recommendations for future research are given.
by Caspar Andri Largiadèr.
S.M.
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Rooney, Colum. "Blood vessel diameter in glaucoma." Thesis, Aston University, 2016. http://publications.aston.ac.uk/30071/.
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Glaucoma is a leading cause of visual disability in the UK and major referral reason between high street optometry and hospital based ophthalmology. The standard optometric tests used to determine necessity of referral are currently leading to a high false positive burden on glaucoma clinics. The disease of glaucoma is considered to be multifactorial in the reasons for its onset and progression. An increasing body of research proposes a vascular dysregulation hypothesis, and retinal artery diameter reduction, as a recognisable risk factor for both the onset and progression of glaucoma. The Heidelberg Retina Tomograph (HRT) is a commercially available laser scanning ophthalmoscope designed principally for the detection of glaucoma by evaluation of the optic disc neuroretinal rim. An additional ability of the HRT is to measure, via an interactive window, the blood vessels of the scanned image without the need for export of the image or magnification to view them in detail. This thesis contributes to the field of early glaucoma detection by measurement of artery diameter via the interactive window on the HRT machine. The volunteers were divided into three groups normal, glaucoma and ocular hypertensive (OHT) and followed over a period of one year to determine if vessel diameter changed in relation to visual field or neuroretinal rim parameters. The main results in this thesis show that artery diameter does change with glaucoma onset and that the HRT machine is a valid instrument for collection of this data.
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Stenzel, D. "Functional diversity of extracellular matrix components during vessel migration, endothelial sprouting and blood vessel stabilization." Thesis, University College London (University of London), 2009. http://discovery.ucl.ac.uk/18782/.
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The formation of mature blood vessels requires recruitment of mural cells (MC) and generation of an extracellular matrix in order to stabilize and support the nascent vessel. The precise sequence of basement membrane protein expression and function during initiation, elongation and stabilization of the angiogenic sprout remains unclear. The first project describes a function of astrocytic Fibronectin (FN) in guided vessel migration. Integrin-binding is dispensable for fibrilliar FN assembly but mediates endothelial cell adhesion in vivo. VEGF-A dependent migration of retinal vessels requires PI3K activity and astrocytic FN possibly functions to retain VEGF protein on the astrocytic matrix. In a second project we discovered endothelial tip cells-specific expression of laminin alpha4 (Lama4) and provide first evidence for an influence of laminin α4 on endothelial Dll4/Notch signalling in sprouting angiogenesis. Loss of Lama4 leads to increased filopodia formation, tip cell numbers and consequently increased vessel density, resembling the phenotype of disturbed Dll4/Notch signalling. Loss of Lama4 leads to reduced Dll4 and Notch target gene expression, whereas gain-of-function results in increased Dll4 expression in vitro. Preliminary results suggest that laminin α4 induced Dll4 expression involves both VEGFR2 and integrin signalling. The third project addresses the cell-autonomous requirement of heparan sulfate (HS) production by MCs during mouse embryonic vascular development. Conditional deletion of HS synthesis in MC caused severe vascular defects and embryonic lethality. Unexpectedly, distinct regions of vascular growth showed selective requirement for MC HS production: whereas MC recruitment in peripheral skin vascularization is severely disrupted, MCs during brain angiogenesis appear unaffected. Similarly, PDGF-B and TGF-β signalling are impaired in the peripheral vessels, but not in the brain. These data suggest that cell-autonomous HS is essential for MC recruitment in the skin vasculature, where induction and differentiation of local progenitor cells from the mesenchymal cell lineage is mediated by TGF-β signalling.
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Bettis, R. J. "Two phase releases following rapid vessel failure." Thesis, London South Bank University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376541.
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Delagrammaticas, Dimitri E. "Development of an In-Vitro Tissue Engineered Blood Vessel Mimic Using Human Large Vessel Cell Sources." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/79.
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Tissue engineering is an emerging field that offers novel and unmatched potential medical therapies and treatments. While the vast aim of tissue engineering endeavors is to provide clinically implantable constructs, secondary applications have been developed to utilize tissue-engineered constructs for in-vitro evaluation of devices and therapies. Specifically, in-vitro blood vessel mimics (BVM) have been developed to create a bench-top blood vessel model using human cells that can be used to test and evaluate vascular disease treatments and intravascular devices. Previous BVM work has used fat derived human microvascular endothelial cells (EC) sodded on an ePTFE scaffold. To create a more physiologically accurate model, a dual layer of large vessel endothelial and smooth muscle cells (SMC) on an ePTFE tube is investigated throughout this thesis. Human umbilical vein endothelial cells (HUVEC) and human umbilical vein smooth muscle cells (HUVSMC) were chosen as the large vessel cell types and cultivated according to standard procedures. Before dual sodding, sodding density experiments with HUVSMC were performed to determine the number of cells required to create a confluent cell layer. HUVSMC sodded by trans-luminal pressure at densities ranging from 3.5x10^5 cells/cm^2 to 1.0x10^6 cells/cm^2 were run for one day to observe luminal coverage. After determining the desirable range for HUVSMC sodding, HUVSMC experiments with 5.0x10^5 cells/cm^2 and 7.5x10^5 cells/cm^2 were run over seven days to evaluate progression of the graft over time. Histology and SEM methods were used for analysis. A HUVEC study was next conducted over 7 days to confirm that the large vessel endothelial cell could be sodded and sustained on ePTFE in-vitro. Next, dual sodding was performed by pressure sodding HUVSMC at 7.5x10^5 cells/cm^2 followed by trans-luminal flow for 30 minutes. HUVECs were subsequently trans-luminally pressure sodded at 5.0x10^5 cells/cm^2 followed by an additional 30 minutes of trans-luminal flow; perfusion flow began following the final 30 minutes of trans-luminal flow. Experiments for the dual layered grafts were run for both one and seven days to evaluate and develop the dual sodding protocol as well as observe the co-culture over time. Analysis of the dual layered grafts was performed by SEM, histology, and fluorescence microscopy. HUVECs were incubated with Cell Tracker™ prior to dual sodding and both cell types with bisbenzimide after graft harvest to attempt to distinguish between cell types. Results from the thesis illustrate that large vessel smooth muscle and endothelial cells can be sodded onto ePTFE scaffolds and sustained within the in-vitro BVM system for up to 7 days. Furthermore, cost analysis demonstrates that the addition of a smooth muscle cell layer adds minimal costs to the BVM system. In conclusion, the studies contained within this thesis culminate in a protocol for the dual sodding of smooth muscle and endothelial cells with the aim of creating a physiologically representative co-culture blood vessel mimic.
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Elyas, S. P. "Differences in vascular function between small vessel disease (SVD) stroke and atherosclerotic large vessel (LVD) stroke." Thesis, Exeter and Plymouth Peninsula Medical School, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.700492.
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Swartbol, Paul. "Blood-graft interactions with special reference to cellular immune-reactivity in vascular and endovascular surgery /." Lund : Dept. of Surgery, Lund University, 1996. http://books.google.com/books?id=GaRsAAAAMAAJ.
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Nar, Fatih. "Vessel Segmentation Using Shallow Water Equations." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613197/index.pdf.
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This thesis investigates the feasibility of using fluid flow as a deformable model for
segmenting vessels in 2D and 3D medical images. Exploiting fluid flow in vessel
segmentation is biologically plausible since vessels naturally provide the medium for
blood transportation. Fluid flow can be used as a basis for powerful vessel
segmentation because streaming fluid regions can merge and split providing
topological adaptivity. In addition, the fluid can also flow through small gaps formed
by imaging artifacts building connections between disconnected areas. In our study,
due to their simplicity, parallelism, and low computational cost compared to other
fluid simulation methods, linearized shallow water equations (LSWE) are used. The
method developed herein is validated using synthetic data sets, two clinical datasets,
and publicly available simulated datasets which contain Magnetic Resonance
Angiography (MRA) images, Magnetic Resonance Venography (MRV) images and
retinal angiography images. Depending on image size, one to two order of magnitude
speed ups are obtained with developed parallel implementation using Nvidia
Compute Unified Device Architecture (CUDA) compared to single-core and multicore
CPU implementation.
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Reinertsen, Ingerid R. "Vessel driven correction of brain-shift." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=111865.
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The displacement and deformation of brain tissue is a major source of error in image-guided neurosurgery systems. This thesis presents the design, implementation and validation of an image registration algortithm to detect and correct brain-shift using pre-operative MR images and intraoperative Doppler ultrasound data. The registration algorithm uses segmented vessels from both modalities, and estimates the displacement using a modified version of the iterative closest point (ICP) algorithm. The least trimmed squares (LTS) was used to reduce the number of outliers in the point matching procedure. The selected points were first used to estimate a linear transformation between the two data-sets, and then used to drive a thin-plate spline transform to achieve non-linear registration.A deformable brain phantom was designed, constructed and characterized in order to serve as a gold standard in the validation of the registration algorithm. The reproducibility of the elastic deformation of the phantom was evaluated using MR imaging and surface measurements. The experiments showed that the phantom was well suited for MR and ultrasound imaging (B-mode and Doppler) with sub-millimeter reproducibility for the deformations.
Validation of the registration technique was then completed in three parts. First, the technique was tested and validated using realistic simulations where the results were compared to the known deformation. The registration technique recovered 75% of the deformation in the region of interest accounting for deformations as large as 20 mm.
Second, a phantom study was performed where both MR and ultrasound images of the phantom were obtained for three different deformations. The registration results based on MR data were used as a gold standard to evaluate the performance of the ultrasound based registration. On average, deformations of 7.5 mm magnitude were corrected to within 1.6 mm for the ultrasound based registration and 1.07 mm for the MR based registration. Finally, the registration algorithm was validated using five retrospective clinical data-sets. Because the true displacement remained unknown, the method was validated using homologous landmarks identified in the original data, the exclusion of selected vessels, and finally manual segmentation of non-vascular structures in anatomical data. The tracking of homologous landmarks show that the registration algorithm was able to correct the deformation to within 1.24 mm, and the validation using excluded vessels and anatomical structures show an accuracy close to 1 mm. Pre-processing of the data can be completed in 30 seconds per dataset, and registrations can be performed in less than 30 seconds. This makes the technique well suited for intra-operative use.
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Sanfilippo, Giorgia. "Turbulence in not fully filled vessel." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Find full textAbstract:
In many chemical and biotechnological processes, mixing represents one of the fundamental unit operations, object of interest in chemical, pharmaceutical and food industries. Mixing efficiency is strongly influenced by the design and operating conditions chosen. The flow field study is important to understand which mechanism takes place in the fluid inside the stirred tank, in particular to characterize the property of the fluid and, to do that, a widely investigation techniques are used.
This experimental work was carried out during the “Erasmus + for traineeship” project carried out at the Chemical Engineering department of the University of Birmingham. It aims to investigate some parameters that influence the fluid dynamics of an agitated system, understanding how they influence it and possibly finding new parameters to define the turbulence of a system.
To achieve this aim, the characteristic parameters of a traditional single-phase system mechanically stirred and their behaviour during mixing have been experimentally studied. To understand the flow field generated in the various operating configurations adopted, an optical diagnostic technique, 2-D PIV, was used.
The work ends with the final considerations developed after analyzing the system both by changing the physical and geometric parameters and how these can affect the turbulence of an agitated system.
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von, Fahnestock Frank Michael. "Niche applications of in-vessel composting." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1127237412.
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Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xvii, 233 p.; also includes graphics (some col.). Includes bibliographical references (p. 185-192). Available online via OhioLINK's ETD Center
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Brown, Sandra Lois School of Design UNSW. "Significance, the vessel and the domestic." Awarded by:University of New South Wales. School of Design, 2004. http://handle.unsw.edu.au/1959.4/20761.
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Throughout history, people have made or acquired vessels from which to sip their favourite beverage. In the contemporary domestic setting, households frequently accumulate multiples of the same type of object in numbers that are considerably greater than is necessary and practical for use alone. Of these many objects there are often individual pieces that have special significance for the owner or user. Some are so valued that they may even be removed and set aside because of their perceived importance. The research was initiated by a previous study of tea drinking vessels coupled with a desire, as an object maker and collector, to find out why people have special items that they designate as personally important. The aim was to identify how significance could be recognised in specific objects and whether the notion that a group of features used to gauge such objects could be conveyed into studio based work. The research outcomes are evidenced in a text-based document (which articulates the theoretical and empirical elements of the enquiry) and a body of creative studio work developed in response to aspects of the investigation. The document encompasses two components of the study. The first references material from the fields of museum and cultural studies, pivotal in focusing the enquiry. This contributed to the compilation of a general and speculative inventory of qualities that might pertain to objects deemed ???significant???. During these early investigations it became evident that a more in depth and contemporary analysis of significant drinking vessels, their owners and/or users was required. A Survey Questionnaire regarding personal use and special drinking vessels preceded a series of Interviews with a selected group of Australia curators, artists, academics and collectors who discussed and analysed their association with a personally significant drinking vessel. Subsequently, the content of these interviews became central to the focus of the research and outcomes. The research isolates a number of attributes that are commonly identified in objects that, whatever their condition, are deemed ???significant???. These describe the maker, usage, ownership, association and historical context. The perceived value or worth of the object for its owner, is recognised as a consequence of significance and declares the object as distinctive. This outcome is clearly validated by the interviews. The studio work develops from the fusion of personal narrative that has been enhanced by findings of the research. In particular, it references the cherished object, most especially those pieces that have been retained despite the ravages of time and use. The resulting work was exhibited as Trace Elements ??? Marking Time: Significance, the Vessel and the Domestic at Kudos Gallery, Paddington in April 2004.
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Zhu, Lei. "Design optimization of pressure vessel shapes." Thesis, University of Strathclyde, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248480.
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Tan, Yan Ying Rhea. "Genetics of cerebral small vessel disease." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/283203.
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Cerebral small vessel disease (SVD) is a leading cause of stroke and vascular dementia. The majority of cases are sporadic, occurring in the elderly hypertensive population. However, there also exist patients with familial disease. The most common form is Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL), caused by mutations in the NOTCH3 gene. In recent years, other genes have also been found to cause familial SVD, such as COL4A1/A2, HTRA1, FOXC1 and TREX1. Genome wide association studies (GWAS) have also revealed loci associated with sporadic SVD strokes and its related features. This thesis explores the genetic basis of SVD primarily from the angle of the 'one gene, one disease' hypothesis. We explore the phenotype of familial SVD using CADASIL as a prototype. We next adopt a candidate gene approach to rare variant discovery using high throughput sequencing (HTS) techniques in two forms: 1) a multi-gene sequencing panel to examine the presence of rare variants in a cohort of 993 presumed-sporadic, early-onset SVD stroke patients, and 2) whole genome sequencing in 118 pedigrees with suspected familial SVD. We also evaluate the prevalence of known disease-causing mutations in the general population using a cohort of whole genome sequenced non-SVD patients, and other control databases. We demonstrate that a few presumed-sporadic SVD stroke patients may in fact have familial disease that was not previously diagnosed. We show that known and novel rare variants in candidate genes are found in our cohort of familial SVD patients, and suggest a possible role for rare variants in genes associated with related phenotypes and sporadic disease in this cohort. Finally, we identify known disease-causing variants in relatively high frequencies in the population, and show that conclusions on the pathogenicity of variants based on allele frequency and functional analyses may sometimes be misguided, thus highlighting the current limitations we face in the clinical interpretation of variants identified on HTS. In recent years genetic studies have revealed that pathways in different familial diseases are likely to converge in the pathogenesis of sporadic disease. Further uncovering the genetic basis of undiagnosed cases of familial SVD may shed light on the mechanisms underlying the sporadic form of disease, and may in turn drive the identification of potential therapeutic targets.
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Gordon, Mark. "From vessel volumetrics to organic geometics." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1327527145.
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Amatruda, Claudia Maria. "Multiscale modelling of stent/vessel interactions." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/12229/.
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Angioplasty with stenting re-opens stenosed arteries, but in-stent restenosis remains a common negative outcome. Correlations between local mechanical stimuli and ISR have been reported, explained by mechanotransduction mechanisms that influence cell behaviour. This thesis investigates the loads imposed on the coronary artery following stent implantation. The changes in mechanical stimuli in a vessel following stent deployment were initially considered using a simple MATLAB model, followed by analysis of a 2D cross-section model to represent variation of stress with stent strut distribution. This model revealed the distribution of the stress through the thickness and around the circumference varied significantly for high expansion ratios and uneven strut distributions. A 3D continuum model of stent geometry post-expansion, obtained from micro-CT images, was used to analyse stent interaction with an idealised vessel geometry. The structural stress at the level of individual struts was compared to histological data and to fluid dynamic simulations of the same stent/vessel geometry. When structural and fluid dynamic stimuli were considered together, correlations with the amount of neointimal growth became more significant than when they were considered individually. This suggests that both stimuli contribute to the development of neointimal growth and their combination may accelerate the progression of ISR. Finally, the thesis describes a model of the evolution of in-stent restenosis. A cellular model of growth was developed to include feedback from a finite element model of the vessel and neointima. Change in the lumen geometry was captured with neointimal growth, an updated geometry was passed to the finite element model to compute the subsequent change of stress direction on cells during their growth. The results show encouraging resemblance with histological images of ISR, especially for the early phases of growth. The thesis concludes with a summary of the modelling results and a review of opportunities for further research.
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Bower, Thomas Charles. "Fishing vessel optimization : a design tool." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25082.
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Rising fuel costs and decreased catch sizes have reduced the fishing vessel owners profit margin. This has caused the owners to try to find methods that reduce the costs of their operations. In this thesis a tool which can be used by fishing vessel designers, and operators, is developed for use at the preliminary ship design stage. It is used to determine the best fishing vessel parameters for a given operational scenario found on the West Coast of Canada.Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate
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Potter, Gillian Margaret. "Neuroimaging of cerebral small vessel disease." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5598.
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Lacunar stroke accounts for one quarter of all ischaemic stroke and in the long term carries a greater risk of death and disability than was previously realised. Much of our current knowledge originated from neuropathological studies in the 1950s and 1960s. In the last thirty years, brain computed tomography (CT) and magnetic resonance imaging (MRI) have revolutionised our understanding of lacunar stroke and associated features of cerebral small vessel disease (SVD), namely white matter lesions (WML), enlarged perivascular spaces (EPVS) and brain microbleeds (BMB). The purpose of the projects which led to the writing of this thesis was to improve understanding of imaging characteristics of cerebral SVD. We aimed to assess (i) clinical and imaging features which might explain misclassification of lacunar infarcts as cortical infarcts and vice versa, (ii) the proportion of symptomatic lacunar infarcts progressing to lacunar cavities and associations of cavitation, (iii) completeness of reporting of lacunar lesions in the lacunar stroke literature, (iv) definitions and detection of lacunar lesions amongst SVD researchers, (v) the relationship between WML and carotid stenosis, (vi) clinical and imaging associations of EPVS and, (vii) observer variability in the assessment of EPVS and BMB, in order to develop visual rating scales. Section one describes neuroimaging of lacunar stroke. To investigate features which might explain clinical stroke subtype misclassification (‘clinical-imaging dissociation’), I used data from a stroke study. The main factor associated with clinical-imaging dissociation was diabetes, and in patients with acute lacunar infarction, proximity of the lacunar infarct to the cortex, age, diabetes and left hemisphere location. To investigate the proportion of symptomatic lacunar infarcts progressing to cavities, I used data from two stroke studies. A fifth of patients with acute lacunar ischaemic stroke showed definite cavitation on follow-up imaging at a median of 227 days; cavitation was associated with increasing time to follow-up. To assess completeness of reporting of lacunar lesions in the lacunar stroke literature, I reviewed 50 articles from three journals with a stroke focus. There was marked variation in terminology and descriptions of imaging definitions of lacunar lesions. To assess lacunar lesion definitions and detection amongst SVD researchers, I used an online survey consisting of case-based and non-case-based questions. There was marked variation in definitions and descriptions. Cavitated lesions were detected with the highest degree of confidence. Section two describes neuroimaging of associated features of cerebral SVD. Using data from two stroke studies, I examined the relationship between WML and ipsilateral carotid artery stenosis. There was no association between carotid stenosis and WML. I tested the association of EPVS with WML and lacunar stroke subtype using data from a stroke study. Total EPVS were associated with age and deep WML; basal ganglia (BG) EPVS were associated with age, centrum semiovale (CS) EPVS, cerebral atrophy and lacunar stroke subtype. Quantification of observer variability in EPVS rating was assessed on 60 MRI scans selected from a stroke study and an ageing cohort. Intrarater agreement was good and interrater agreement was moderate. Main reasons for interrater disagreement included the visualisation of very small EPVS and the presence of concomitant WML and lacunar lesions. Observer variability in BMB rating was quantified using MRI scans from a stroke study. Interrater agreement was moderate but improved following modification of the pilot rating scale (BOMBS; Brain Observer MicroBleed Scale), which had its main effect by differentiating ‘certain’ BMB from ‘uncertain’ BMB and BMB ‘mimics’. In conclusion, neuroimaging, particularly MRI, is a valuable tool for the investigation of lacunar stroke and associated features of cerebral SVD. With recent technological advances in both CT and MRI, neuroimaging will remain central to future SVD studies, hopefully leading to a much improved understanding of this important disease.
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Smith, Aubrey N. "CHARACTERIZATION AND IMPLEMENTATION OF A DECELLULARIZED PORCINE VESSEL AS A BIOLOGIC SCAFFOLD FOR A BLOOD VESSEL MIMIC." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/589.
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Every 34 seconds, someone in the United States suffers from a heart attack. Most heart attacks are caused by atherosclerotic build up in the coronary arteries, occluding normal blood flow. Balloon angioplasty procedures in combination with a metal stent often result in successful restoration of normal blood flow. However, bare metal stents often lead to restenosis and other complications. To compensate for this problem, industry has created drug-eluting stents to promote healing of the artery wall post stenting. These stents are continually advancing toward better drug-eluting designs and methods, resulting in a need for fast and reliable pre-clinical testing modalities. Dr. Kristen Cardinal recently developed a tissue engineered blood vessel mimic, with the goal of testing intravascular devices. However, the scaffold component of this model exhibits several physiological limitations that must be addressed to create a truly biomemtic BVM. The current model uses expanded poly(terafluorethylene) [ePTFE] or poly(lactic-go-glycolide) [PLGA] as the choice material for the scaffold. EPTFE has several advantages as it is a widely recognized biomaterial. However, ePTFE is very expensive and lacks native mechanical properties. PLGA is another polymer that is created in-house to produce a uniquely tailored scaffold for use in the BVM; resulting in a cheaper alternative scaffold material. However, PLGA again lacks the necessary native mechanical properties to properly mimic an in-vivo artery. The creation of a biological scaffold will provide a unique biomimetic material to most accurately recapitulate the artery in-vitro.
Decellularization is the process of removing all cellular components from a tissue, leaving an acellular structure of extracellular matrix. Understanding the clinical problem and the potential of the BVM, the aim of this thesis is to develop the decellularization process for the creation of a biologic scaffold as a replacement to the non-physiologic polymer scaffolds for the BVM. The first phase of this thesis was to develop and optimize an acceptable protocol for the decellularization of porcine arteries. The use of a 0.075% sodium dodecyl sulfate detergent was sufficient for complete removal of all vascular cell types, without significant degradation to the scaffold wall. In the second phase of this thesis, the decellularized scaffolds were mechanically tested to ensure retention of their native properties. The longitudinal and radial properties of the scaffold were found to be similar to the native artery, indicating the decellularized scaffold improves several physiologically aspects when compared to a polymer scaffold. These mechanical attributes improve the testing environment when evaluating sent deployment or new balloon angioplasty devices; as the decellularized scaffold has an phsyiolgical compliance. The final phase of this thesis examined the cellular adhesion capacities of the scaffold through recellularization with human umbilical vein endothelial cells (hUVECS). Fluorescent microscopy analysis suggests uniform attachment of cells along the length of the scaffold creating a monolayer. These results indicate this new scaffold type can develop an endothelium to complete the ideal, most physiologically relevant BVM system. Further optimization of the decellularization procedures could enhance the ability of the scaffold to be cultured for long-term interaction with intravascular devices.
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Goronovski, Andrei. "Influence of In-vessel Pressure and Corium Melt Properties on Global Vessel Wall Failure of Nordic-type BWRs." Thesis, KTH, Kärnkraftsäkerhet, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-139534.
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The goal of the present study is to investigate the effect of different scenarios of core degradation in a Nordic-type BWR (boiling water reactor) on the reactor pressure vessel failure mode and timing. Specifically we consider the effects of (i) in-vessel pressure, (ii) melt properties. Control rod guide tube (CRGT) cooling and cooling of the debris from the top are considered as severe accident management (SAM) measures in this study. We also consider the question about minimal amount of debris that can be retained inside the reactor pressure vessel (RPV). Analysis is carried out with coupled (i) Phase-change Effective Convectivity (PECM) model implemented in Fluent for prediction of the debris and melt pool heat transfer, and (ii) structural model of the RPV lower head implemented in ANSYS for simulation of thermo-mechanical creep. The coupling is done through transient thermal load predicted by PECM and applied as a boundary condition in ANSYS analysis. Results of the analysis suggest that applying only CRGT and top cooling is insufficient for maintaining vessel integrity with 0.4 m deep (~12 tons) corium melt pool. The failure of the vessel by thermally induced creep can be expected starting from 5.3 h after the dryout of the debris bed in the lower plenum. However, earlier failure of the instrumentation guide tubes (IGTs) is possible due to melting of the nozzle welding. The internal pressure in the vessel in the range between 3 to 60 bars has no significant influence on the mode and location of the global RPV wall failure. However, depressurization of the vessel can delay RPV wall failure by 46 min for 0.7 m (~ 30 tons) and by 24 min for 1.9 m (~ 200 tons) debris bed. For 0.7 m pool case, changes in vessel pressure from 3 to 60 bars caused changes in liquid melt mass and superheat from ~18 tons at 180 K to ~13 tons at 100 K superheat, respectively. The same changes in pressure for 1.9 m case caused changes in liquid melt mass and superheat from ~40 tons at 42 K to ~10 tons at about 8 K superheat, respectively. Investigation of the influence of melt pool properties on the mode and timing of the vessel failure suggest that the thermo-mechanical creep behavior is most sensitive to the thermal conductivity of solid debris. Both vessel wall and IGT failure timing is strongly dependent on this parameter. For given thermal conductivity of solid debris, an increase in Tsolidus or Tliquidus generally leads to a decrease in liquid melt mass and superheat at the moment of vessel wall failure. Applying models for effective thermal conductivity of porous debris helps to further reduce uncertainty in assessment of the vessel failure and melt ejection mode and timing. Only in an extreme case with Tsolidus, Tliquidus range larger than 600 K, with thermal conductivity of solid 0.5 W∙m‑1∙K‑1 and thermal conductivity of liquid melt 20 W∙m‑1∙K‑1, a noticeable vessel wall ablation and melting of the crust on the wall surface was observed. However, the failure was still caused by creep strain and the location of the failure remained similar to other considered cases.APRI-8
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Holm, Sven. "Optical imaging of retinal blood flow : studies in automatic vessel extraction, alignment, and driven changes in vessel oximetry." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/optical-imaging-of-retinal-blood-flow-studies-in-automatic-vessel-extraction-alignment-and-driven-changes-in-vessel-oximetry(f39850b2-8f9c-4d7a-b8fa-370e313e2cc4).html.
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Recent advances in retinal imaging have made it possible to take measurements of retinal oxygen saturation noninvasively in humans. This allows studying the supply of oxygen in healthy and diseased retinae, thereby advancing our understanding of both the normal functioning of the retina and of retinal pathologies. However, retinal oximetry is still a research tool only and requires further improvement before being used in a clinical setting. Here, a single-wavelength flickering light was used to increase retinal blood flow in healthy subjects. This increase is revealed by both vasodilation and an increase in retinal oxygen saturation. A flickering light stimulus provides the means to assess the sensitivity of any retinal oximetry system, as such systems should be able to pick up this increase in retinal blood flow. In addition, the flickering light allows for com- parison to be made within rather than between subjects and can be used to examine the activation of the eye. This reduces the influence of potential confounding factors between subjects including differences in fundus pigmentation and illumination. The most commonly used method to measure retinal oxygenation is the optical density ra- tio (ODR) approach. The standard approach is to compute the average ODR for each vessel segment by combining the hundreds of individual ODR readings and then to use the mean of these segment averages as a measure of oxygen saturation. Alternatively, it has been suggested that the peak location of Gaussian functions fitted to histograms of individual ODR readings can be used as an measure of retinal oxygenation. In response to a 10Hz flickering light, the venular diameter increased by 3.44% (SEM: ±0.53%) (n=16, p<0.05) and the arteriolar diameter by 1.87% (±0.72 %) (p<0.05). The optical density ratio, measured with the Gaussian fit, decreased in the venules from 0.713 (±0.015) to 0.694 (±0.015) (p<0.05). No changes in arteriolar optical density ratios were measured. The post-flicker measurement was computed as the average of up to four post-flicker datasets obtained at 10s, 20s, 30s and 40s after onset of flickering. These results suggest that the flickering light increased retinal blood flow. The mean absolute percentage error was lower in venules for the Gaussian fit method than for the gold standard method for datasets taken at 30s and 40s after onset of flickering. Thus, the Gaussian fit method was more robust. All measurements were taken with a custom-made retinal oximeter. The pixel intensity of the blood vessel and the intensity on either side of the vessel had to be extracted to compute the individual optical density ratios. This required the automatic extraction of the retinal vasculature. Two such algorithms were developed and applied to two databases of retinal fundus images: the DRIVE and the novel DR HAGIS database. One algorithm was purely based on the pixel intensities, while the other made use of oriented Gabor filters. These two algorithms segmented the images to a similar accuracy (DRIVE: 94.56% and 94.54%, DR HAGIS: 95.83% and 95.71% for the intensity and Gabor filter based algorithm, respectively) and performed as well as a human expert (DRIVE: 94.73%). These algorithms were of sufficient quality to extract individual segments for the oximetry study and to align fundus images.
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Bucciarelli, Elia. "Liquid-liquid dispersion in mechanically agitated vessel." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
Find full textAbstract:
L’argomento trattato è lo studio di due liquidi immiscibili all’interno di un recipiente agitato.
Una nuova tecnica di misura delle dimensioni delle particelle viene presentata, la tecnica sperimentata è non invasiva in quanto tutti gli strumenti di misura sono stati posizionati esternamente al vessel.
Il recipiente conteneva una dispersione di olio siliconico in acqua, i test sono stati condotti in assenza di coalescenza.
Il sistema è agitato in un primo test da una girante Rushton e in un secondo da una girante con denti; esso consiste in un recipiente cilindrico dal diametro T=300mm in vetro, questo vessel è stato inserito in un secondo recipiente, anch’esso in vetro ma dalla geometria cubica, riempito di acqua per ridurre problemi legati alla distorsione ottica dovuta alla cilindricità delle pareti del vessel agitato.
Il recipiente è stato posto tra una fotocamera ad alta velocità e una lampada avente lo scopo di illuminare la dispersione. Sono state quindi relazionate le reali dimensioni in mm delle gocce, con i pixel della fotocamera nella fase di calibrazione; la taratura è stata effettuata tramite l’utilizzo di speciali sfere solide monodimensionali.
L’analisi della dispersione in esame consisteva nella cattura di più set di immagini ad intervalli di tempo prestabiliti, solo dopo che la dispersione fosse arrivata all’equilibrio.
La foto sono state quindi salvate in stack ed analizzate da un apposito codice che è stato scritto per il programma di analisi di immagini utilizzato: ImageJ. La possibilità di implementare macro in ImageJ rende molto flessibile questo programma, caratteristica fondamentale in questo lavoro in quanto lo studio di questi liquidi ha richiesto un notevole numero di test per ottenere una corretta interpretazione delle dimensioni delle gocce.
Segue infine l’analisi dei dati ottenuti, alcune correlazioni riportate in letteratura sono state verificate statisticamente a partire dai risultati ottenuti.
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Bonnín, Pascual Francisco. "Contributions to Robot-based Vessel Visual Inspection." Doctoral thesis, Universitat de les Illes Balears, 2017. http://hdl.handle.net/10803/543844.
Full textAbstract:
[cat]El transport marítim és una de les maneres més efectives de transportar béns d’un lloc a l’altre
del món. Encara que avui dia es realitzen grans esforços per tal d’evitar els accidents
marítims, aquests encara ocorren i, de tant en tant, tenen conseqüències catastròfiques en
termes ambientals, humans i/o econòmics. Els problemes estructurals causats per esquerdes
i/o corrosió són la causa principal d’aquests accidents i, per això, els vaixells són sotmesos a
ins-peccions periòdiques amb l’objectiu de garantir la seva integritat estructural. Per dur a
terme una inspecció, els vaixells són buidats i portats a una drassana on s’instal·len bastides
que permeten als inspectors arribar a les zones més altes de la seva estructura. Aquestes
inspeccions es realitzen sovint en compartiments perillosos o de difícil accés. En termes
econòmics, el procés pot suposar un desemborsament de fins a un milió de dòlars. Per tot
això, qualsevol contribució que suposi una reducció en el temps/cost de la inspecció, o un
increment en la seguretat dels operaris, està justificada. En aquesta tesi es proposen noves
eines tecnològiques que pretenen contribuir al redisseny dels processos d’inspecció visual de
vaixells. D’una banda, es proposa una nova plataforma robòtica aèria que permet a l’operari
realitzar la ins-pecció del vaixell des d’una posició segura i còmoda. Aquesta plataforma
consisteix en un dispositiu de fàcil ús que ha estat desenvolupat seguint el paradigma de
l’Autonomia Supervisada, de tal manera que el vehicle s’encarrega de totes les tasques
referents a la seguretat, mentre que l’operari proporciona les consignes de desplaçament i pot
centrarse en el procés d’inspecció. D’altra banda, es proposen diversos algorismes basats en
visió per a la detecció de defectes en l’estructura del vaixell. En primer lloc, es proposen
diversos mètodes per a la detecció de corrosió, basats en la combinació de diferents
descriptors de color i de textura. En segon lloc, es proposa un algorisme per a la detecció
d’esquerdes que combina l’extracció de contorns amb un procés de creixement de regions.
Finalment, s’avalua el concepte de notorietat per a la detecció de defectes genèrics, i per a la
millora del rendiment dels detectors de corrosió i d’esquerdes. La plataforma robòtica i els detectors de defectes proposats han estat avaluats tant en laboratori com durant proves de
camp realitzades a bord d’un vaixell real. Els resultats obtinguts permeten confirmar la utilitat i
el bon rendiment de les diferents eines tecnològiques propostes.[spa]El transporte marítimo es una de las maneras más efectivas de transportar mercancías de un lugar a otro del mundo. Aunque hoy en día se llevan a cabo muchos esfuerzos para evitar los accidentes marítimos, estos todavía ocurren y, de vez en cuando, tienen consecuencias catastróficas en términos ambientales, humanos y/o económicos. Los daños estructurales causados por grietas y/o corrosión son la causa principal de estos accidentes y, por ello, los barcos son sometidos a inspecciones periódicas con el objetivo de garantizar su integridad estructural. Para llevar a cabo una inspección, los barcos son vaciados y llevados a un astillero donde se instalan andamiajes para permitir a los inspectores alcanzar las zonas más altas de su estructura. Estas inspecciones se realizan muchas veces en entornos peligrosos o de difícil acceso. En términos económicos, el proceso puede suponer un desembolso de hasta un millón de dolares. Por todo ello, cualquier contribución que suponga una reducción en el tiempo/coste de la inspección, o un incremento en la seguridad de los operarios, está justificada. En esta tesis se proponen nuevas herramientas tecnológicas que pretenden contribuir al rediseño de los procesos de inspección visual de barcos. Por un lado, se propone una nueva plataforma robótica aérea que permite al operario realizar la inspección del barco desde una posición segura y cómoda. Esta plataforma consiste en un dispositivo de fácil manejo que ha sido desarrollado siguiendo el paradigma de la Autonomía Supervisada, de tal manera que el vehículo se encarga de todas las tareas referentes a la seguridad, mientras que el operario proporciona las consignas de desplazamiento y puede centrarse en el proceso de inspección. Por otro lado, se proponen diversos algoritmos basados en visión para la detección de defectos en la estructura del barco. En primer lugar, se proponen varios métodos para la detección de corrosión, basados en la combinación de diferentes descriptores de color y de textura. En segundo lugar, se propone un algoritmo para la detección de grietas que combina la extracción de contornos con un proceso de crecimiento de regiones. Finalmente, se evalúa el concepto de notoriedad para la detección de defectos genéricos, y para la mejora del rendimiento de los detectores de corrosión y de grietas. La plataforma robótica y los detectores de defectos propuestos han sido evaluados tanto en laboratorio como durante pruebas de campo realizadas a bordo de un barco real. Los resultados obtenidos permiten confirmar la utilidad y el buen rendimiento de las diferentes herramientas tecnológicas propuestas.
[eng]Vessels are nowadays one of the most cost effective ways to transport goods around the world. Despite the efforts to avoid maritime accidents, these still occur and, from time to time, have catastrophic consequences in environmental, human and/or economic terms. Structural failures caused by cracks and/or corrosion are the main cause of these accidents and, as such, vessels are submitted to periodical inspections in order to ensure their structural integrity. To carry out this task, vessels have to be emptied and situated in a dockyard where high scaffoldings are installed to allow the human inspectors to reach the highest parts of the vessel structure. Besides, the surveys are on many occasions performed in hazardous environments with difficult access. In economic terms, total expenses can reach up to one million dollars. Therefore, it is clear that any level of automation of the inspection process that can lead to a reduction of the inspection time, a reduction of the financial costs and/or an increase in the safety of the operation is fully justified. In this regard, this dissertation presents novel technological tools to contribute to re-engineering the process of vessel visual inspection. On the one hand, a novel aerial robotic platform is proposed to allow the surveyor to perform a proper inspection from a safe and comfortable position. It consists in an easy-to-use device which has been developed around the Supervised Autonomy paradigm, so that the vehicle is in charge of all the safety-related issues, while the surveyor provides the displacement commands and focuses on the inspection process. On the other hand, novel vision-based algorithms for defect detection on vessels structures are proposed. Firstly, several corrosion detection methods are described, based on the combination of different colour and texture descriptors. Secondly, a crack detection method, which combines edge detection with a region growing procedure, is proposed. Finally, the idea of saliency for detecting generic defects on vessel structures is evaluated, and also to improve the performance of the corrosion and crack detectors. The aerial platform and the defect detectors are evaluated both under laboratory conditions and during field tests performed on board real vessels. The results obtained allow to confirm the usability and the good performance of all the proposed technological tools.
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Saad, Ashraf A. "Vessel recognition in color Doppler ultrasound imaging /." Thesis, Connect to this title online; UW restricted, 2008. http://hdl.handle.net/1773/5976.
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Sexton, Anita-Jane. "Local control of human umbilical vessel tone." Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321660.
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Truncer, James. "Steatite vessel manufacture in Eastern North America /." Oxford, England : Archaeopress, 2004. http://books.google.com/books?id=NSVmAAAAMAAJ.
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Truncer, James Joseph. "Steatite vessel manufacture in Eastern North America /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/6569.
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Kini, Keertan. "Vessel : a lightweight container for network analysis." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113139.
Full textAbstract:
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 59-61).
TCP adaptation and retransmission strategies provide robust advantages by abstracting the development of applications on the Internet from the development of lower layers. However, the abstraction hides useful low-level information from researchers and administrators who could otherwise use the insights from the performance of TCP and lower layers to diagnose problems and improve TCP performance. Though common tools exist for manual analysis of TCP performance, some of these tools are outdated or arduous to easily use. The primary contribution of this thesis is Vessel, a tool to supplement existing tools with per-connection instrumentation, improving the ability to perform network analysis tests while providing sufficiently detailed information to identify differences with different tests. Vessel leverages the Extended Berkeley Packet Filter and Linux network namespaces. We demonstrate the utility of the tool by analyzing TCP flows associated with competing web-based speed measurement tests
by Keertan Kini.
M. Eng.
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Salem, Nancy M. "Retinal image processing for blood vessel segmentation." Thesis, University of Liverpool, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.441934.
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Townsend, Nicholas Charles. "Influencing and influences of marine vessel motions." Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/207697/.
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With the aim of understanding and improving the sea keeping performance of marine craft the research addresses methods of influencing the motions of marine craft by stabilisation mechanisms, and identifying the influences on RIB motions. The two research projects, that attracted industrial support, represent two separate industrial interests concerned with influencing and understanding the influences on the sea keeping performance of marine craft. The first project, focused on developing a motion control system, for motion reduction and/or control of marine structures operating in the free-surface. The aim was to develop a system that would replace, eliminate or complement the use of current devices, in order to improve passenger comfort, overcoming the drawbacks of external hydrodynamic based systems. The research developed a new motion control system and theoretical and physical experimental studies were conducted. The second project, focused on identifying the influence of a RIB tube and the properties of the tube, on the dynamic motions of a RIB, including the effect of the motions on the occupants. Theoretical and experimental studies at full and model scale were conducted.
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Abraham, Nicole M. "Evaluation of Blood Vessel Mimic Scaffold Biocompatibility." DigitalCommons@CalPoly, 2021. https://digitalcommons.calpoly.edu/theses/2313.
Full textAbstract:
The Tissue Engineering Research Lab at California Polytechnic State University, San Luis Obispo focuses on creating tissue-engineered blood vessel mimics (BVMs) for use in preclinical testing of vascular devices. These BVMs are composed of electrospun scaffolds made of an assortment of polymers that are seeded with different cell types. This integration of polymers with cells leads to the need for biocompatibility testing of the polymer scaffolds. Many of the lab’s newest scaffolds have not been fully characterized for biologic interactions. Therefore, the first aim of this thesis developed methods for in vitro cytotoxicity testing of polymers used in the fabrication of BVMs. This included cytotoxicity testing using direct contact and elution-based methods, along with fluorescent staining to visualize the scaffold effects on cells.
The second aim of this thesis implemented the newly developed cytotoxicity protocols to evaluate the biocompatibility of existing polymers, ePTFE and PLGA, used in the tissue engineering lab. The results demonstrated that ePTFE and PLGA were noncytotoxic to cells. The third aim of this thesis evaluated the biocompatibility of novel polymers used to fabricate BVMs: PLGA with salt, PLLA, and PCL. Elution-based methods concluded that PLGA with salt, PLLA, and PCL were noncytotoxic to cells; however, the direct contact method illustrated PLGA with salt and PCL were mildly cytotoxic at 24 and 48 hours. Potential causes of this variability include the addition of salt to PLGA, dissolving PCL in dichloromethane, inadequate sample sizing, and the inherent differences between the test methods. Overall, this thesis developed and implemented methods to evaluate the biocompatibility of polymer scaffolds used in the BVM model, and found that ePTFE, PLGA, and PLLA scaffold materials were biocompatible and could be implemented in future BVM setups without concerns. Meanwhile, PLGA with salt and PCL’s toxicity was mild enough to urge future cytotoxicity testing on PLGA with salt and PCL before further use in the lab.
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Vega, Fink Felipe 1991. "Vessel routing problem under uncertainty of demand." Tesis, Universidad de Chile, 2014. http://www.repositorio.uchile.cl/handle/2250/129776.
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Seminario para optar al grado de Ingeniero Comercial, Mención AdministraciónIn this paper it is introduced an optimization to solve the Vehicle Routing Problem (VRP) with uncertainty of demand. The focus is to minimize the transportation costs while satisfying all the given constraints of the problem. The demand uncertainty is solved by applying a distribution fitting to the historical demand data provided by a break-bulk sea shipping company; therefore this is a real world implementation of the VRP with uncertainty of demand. Various scenarios are generated, each with randomized demand from each port’s distribution. Keywords: Optimization, vehicle routing, demand uncertainty, distribution fitting
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Madabushi, Venugopal Arun. "A computational approach to study the effect of multiple lymphangion coordination on lymph flow." Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/2670.
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The lymphatic system acts to return fluid from the interstitial space back into the blood circulation. In normal conditions, lymphangions, the segment of lymphatic vessel in between valves, cyclically contract and can pump lymph from low pressure tissues to the higher-pressure veins of the neck. With edema, however, this pressure gradient can reverse, and the role of contraction is less clear. Like ventricles, lymphangions are sensitive to both preload and afterload. Unlike ventricles, lymphangions are arranged in series, so that the outlet pressure of one lymphangion becomes the inlet pressure of another. Anything that alters the relative timing and frequency of adjacent lymphangions alters both preload and afterload of each lymphangion and thus mean lymph flow. To explore the effect of timing and frequency of contraction on lymph flow, we developed a computational model of a lymphatic vessel with lymphangions described by the classic description of time-varying elastance. When pumping up a pressure gradient, as in normal conditions, or when pumping down a pressure gradient, as in some cases of edema, we found that flow was optimized when the lymphangions in the vessel were pumping with a very short time delay between their cycles, and the flow was reduced when the time delay between the contractions was reduced to zero. However, a difference in frequency between adjacent lymphangions alters instantaneous flow but does not affect mean flow. These results suggest an important role for the timing of the contraction in optimizing lymph flow. However, a difference in frequencies between adjacent lymphangions has little effect on altering lymph flow, suggesting that tight control of lymphangion coordination may not be critical for lymphatic function.
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Hassel, Martin. "Underreporting of maritime accidents to vessel accident databases." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-11488.
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Underreporting of maritime accidents is a problem not only for authorities trying to improve maritime safety through legislation, but also to risk management companies and other entities using maritime casualty statistics in risk and accident analysis. This study has collected and compared casualty data from 01.01.2005 to 31.12.2009, from IHS Fairplay and maritime authorities from Norway, Sweden, Denmark, the United Kingdom, the United States of America, Canada, Greece and the Netherlands. Comparison of data to find common records has been done manually, while estimation of the true number of occurred accidents has been done by using conditional probability given positive dependency between data sources, several variations of the capture-recapture method (Lincoln-Petersen, Chapman and Chao), calculation of the best case scenario, assuming perfect reporting, and finally scaling up a subset of casualty information from Ceforʼs Nordic Marine Insurance Statistics Database. Estimated upper limit reporting performance for the selected flag states range from 7% (Greece) to 74% (Canada), while the estimated coverage of IHS Fairplay ranges from 4% (USA) to 62% (Canada). This study has found that on average, across the board, the amount of accidents that go unreported make up roughly 50% of all occurred accidents. Even in a best case scenario, only a few flag states come close to perfect reporting (Sweden, 94%). Based on the authorʼs assessment of the data quality from the flag state authorities, most emphasis should be placed on the results for Norway (41% of accidents are not reported), The United Kingdom (56% of accidents are not reported) and Canada (10% of accidents are not reported). This study not only proves, by the fact that some casualty data are exclusively in only one database, that underreporting exists, but also that it is a major problem. The best flag state in this study, Canada, is missing roughly a quarter of all accidents occurring in their area of responsibility. Norway and The United Kingdom covers just over a third of all occurred accidents in their area of responsibility, despite these flag state authoritiesʼ high level of perceived competency and quality. The large amount of underreporting uncovered by this study, indicates that all users of statistical data should assume a certain amount of underreporting, and adjust their analyses accordingly. Whether they use a correction factor, safety margin or rely more heavily on expert judgement, must be decided on a case by case basis, as inaccurate basic data most often will have a significant impact on the end result. Keywords: Maritime accidents, risk analysis, underreporting, accident statistics, capture-recapture.
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Ikenyiri, Udo Okwuchukwu. "Conceptual Design of Purpose-Built Diving Support Vessel." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-11539.
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The need to explore designs and arrangement configurations that will enhance operational flexibility and sustainability of the DSVs, without jeopardizing their operational efficiency and lifecycle costs (LCC) was crucial in the present study because of the uncertainties inherent in the mapping of the purpose built DSVs for long duration contracts and anticipated depletion in future offshore development projects across the globe. Three design concepts that focused on arrangement of the mission equipment of the DSVs were proposed and developed using system based design approach and design standards for North Seas operation. The designs were evaluated towards five key performance indicators using the Analytic Hierarchy Process. The study found that a DSV with top side modular design for SAT diving system would be flexible and sustainable to operate, while maintaining efficiency and reduced LCC compared to designs that have either their ROV equipment and air diving system or only ROV equipment in standard container modules. The assumptions made about downtime cost influenced this conclusion. However, sensitivity analysis confirms that in the absence of downtime cost, the design concepts which had either ROV equipment and air diving system or only ROV equipment in standard container modules were cost efficient compared to the one with top side modular design for SAT diving system. The targeted markets for the design concepts were the North Sea and Offshore West Africa, and the designs have the capability to operate in both markets.