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Tumour vessel structural analysis and its application in image analysisWang, Po January 2010 (has links)
Abnormal vascular structure has been identified as one of the major characteristics of tumours. In this thesis, we carry out quantitative analysis on different tumour vascular structures and research the relationship between vascular structure and its transportation efficiency. We first study segmentation methods to extract the binary vessel representations from microscope images. We found that local phase-hysteresis thresholding is able to segment vessel objects from noisy microscope images. We also study methods to extract the centre lines of segmented vessel objects, a process termed as skeletonization. We modified the conventional thinning method to regularize the extremely asymmetrical structure found in the segmented vessel objects. We found this method is capable to produce vessel skeletons with satisfactory accuracy. We have developed a software for 3D vessel structural analysis. This software is consisted of four major parts: image segmentation, vessel skeletonization, skeleton modification and structure quantification. This software has implemented local phase-hysteresis thresholding and structure regularization-thinning methods. A GUI was introduced to enable users to alter the skeleton structures based on their subjective judgements. Radius and inter branch length quantification can be conducted based on the segmentation and skeletonization results. The accuracy of segmentation, skeletonization and quantification methods have been tested on several synthesized data sets. The change of tumour vascular structure after drug treatment was then investigated. We proposed metrics to quantify tumour vascular geometry and statistically analysed the effect of tested drugs on normalizing tumour vascular structure. finally, we developed a spatio-temporal model to simulate the delivery of oxygen and 3-18 F-fluoro-1-(2-nitro-1-imidazolyl)-2-propanol (Fmiso), which is the hypoxia tracer that gives out PET signal in an Fmiso PET scanning. This model is based on compartmental models, but also considers the spatial diffusion of oxygen and Fmiso. We validated our model on in vitro spheroid data and simulated the oxygen and Fmiso distribution on the segmented vessel images. We contend that the tumour Fmiso distribution (as observed in Fmiso PET imaging) is caused by the abnormal tumour vascular structure which is further aroused from tumour angiogenesis process. We depicted a modelling framework to research the relationships between tumour angiogenesis, vessel structure and Fmiso distribution, which is going to be the focus of our future work.
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Application of the Master Curve approach to fracture mechanics characterisation of reactor pressure vessel steelViehrig, H.-W., Kalkhof, D. 22 September 2010 (has links) (PDF)
The paper presents results of a research project founded by the Swiss Federal Nuclear Inspectorate concerning the application of the Master Curve approach in nuclear reactor pressure vessels integrity assessment. The main focus is put on the applicability of pre-cracked 0.4T-SE(B) specimens with short cracks, the verification of transferability of MC reference temperatures T0 from 0.4T thick specimens to larger specimens, ascertaining the influence of the specimen type and the test temperature on T0, investigation of the applicability of specimens with electroerosive notches for the fracture toughness testing, and the quantification of the loading rate and specimen type on T0. The test material is a forged ring of steel 22 NiMoCr 3 7 of the uncommissioned German pressurized water reactor Biblis C.
SE(B) specimens with different overall sizes (specimen thickness B=0.4T, 0.8T, 1.6T, 3T, fatigue pre-cracked to a/W=0.5 and 20% side-grooved) have comparable T0. T0 varies within the 1σ scatter band. The testing of C(T) specimens results in higher T0 compared to SE(B) specimens. It can be stated that except for the lowest test temperature allowed by ASTM E1921-09a, the T0 values evaluated with specimens tested at different test temperatures are consistent. The testing in the temperature range of T0 ± 20 K is recommended because it gave the highest accuracy. Specimens with a/W=0.3 and a/W=0.5 crack length ratios yield comparable T0. The T0 of EDM notched specimens lie 41 K up to 54 K below the T0 of fatigue pre-cracked specimens. A significant influence of the loading rate on the MC T0 was observed. The HSK AN 425 test procedure is a suitable method to evaluate dynamic MC tests. The reference temperature T0 is eligible to define a reference temperature RTTo for the ASME-KIC reference curve as recommended in the ASME Code Case N-629. An additional margin has to be defined for the specific type of transient to be considered in the RPV integrity assessment. This margin also takes into account the level of available information of the RPV to be assessed.
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Analysis Of Fiber Reinforced Composite Vessel Under Hygrothermal LoadingSayman, Sumeyra 01 January 2004 (has links) (PDF)
The aim of this study is to develop an explicit analytical formulation based on the anisotropic elasticity theory that determines the behavior of fiber reinforced composite vessel under hygrothermal loading. The loading is studied for three cases separately, which are plane strain case, free ends and pressure vessel cases. For free-end and pressure vessel cases, the vessel is free to expand, on the other hand for plane strain case, the vessel is prevented to expand. Throughout the study, constant, linear and parabolic temperature distributions are investigated and for each distribution, separate equations are developed. Then, a suitable failure theory is applied to investigate the behavior of fiber reinforced composite vessels under the thermal and moisture effects. Throughout the study, two computer programs are developed which makes possible to investigate the behavior of both symmetrically and antisymmetrically oriented layers. The first program is developed for plane strain case, where the second one is for pressure vessel and free-end cases. Finally, several thermal loading conditions have been carried out by changing the moisture concentration and temperature distributions and the results are tabulated for comparison purposes.
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Computer Aided Design And Structural Analysis Of Pressure VesselsKandaz, Murat 01 June 2006 (has links) (PDF)
This study is conducted for the design and analysis of pressure vessels and associated pressurized equipment using various codes and methods. A computer software is developed as the main outcome of this study, which provides a quick and comprehensive analysis by using various methods utilized in codes and standards together with theoretical and empirical methods which are widely accepted throughout the world.
Pressure vessels are analyzed using ASME Boiler and Pressure Vessel Code, whereas auxiliary codes, especially ASCE and AISC codes are utilized for structural analyses of these equipment. Effect of wind, seismic, and other types of loadings are also taken into consideration in detail, with dynamic analyses. Support structures and their auxiliary components are also items of analysis.
Apart from pressure vessels, many pressurized process equipments that are commonly used in the industy are also included in the scope of the study. They include safety valves which are an integral part of those kinds of pressurized or enclosed systems, two of the heat exchanger components with great importance -tubesheets and expansion joints-, and API 650 tanks for oil or water storage.
The computer software called as VESSELAID is written in Microsoft Visual Basic 6.0 using SI units. Design and analysis methods of VESSELAID are based on various code rules, recommended design practices and alternative approaches.
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Development of a tissue engineering strategy to create highly compliant blood vesselsCrapo, Peter Maughan 16 December 2008 (has links)
Compliance mismatch is a significant hurdle to long-term patency in small-diameter arterial bypass grafts. Vascular tissue engineering has the potential to produce compliant, non-thrombogenic small-diameter grafts. However, current engineered grafts are relatively non-compliant, resulting in intimal hyperplasia and graft occlusion when subjected to arterial pressures. This research investigates the mechanical and biological properties of engineered constructs based on a biodegradable synthetic elastomer, poly(glycerol sebacate) (PGS). Several methods for fabricating porous PGS scaffolds in a tubular geometry were developed and compared. Adult baboon vascular cells were cultured in the scaffolds under various in vitro experimental conditions, including variations in initial cell seeding density, the type of scaffold used for culture, culture time, scaffold material, and hydrostatic pressure, and properties of the resultant constructs were compared.
Scaffold fabrication using heat-shrinkable mandrels and glass tubes coated with hyaluronic acid significantly decreased tolerances of wall thickness and mechanical properties, improved handling, and decreased culture time required to reach luminal cellular confluence compared to scaffolds made with other fabrication techniques. Altering scaffold material from PGS to poly(lactide-co-glycolide) (PLGA), a benchmark biomaterial, did not affect scaffold yield, porosity, or luminal cellular confluence. Extracellular matrix (ECM) deposition increased with SMC-only culture time, and ECM deposition and remodeling during culture influenced construct compliance. Compared to PLGA scaffolds, PGS scaffolds promoted elastin crosslinking by SMCs and elastic tissue properties but attenuated collagen deposition. Hydrostatic pressure promoted ECM synthesis and deposition by SMCs and decreased construct compliance. Collagen and crosslinked elastin content in constructs correlated positively with construct burst pressure, and a negative correlation dependent on scaffold type was found between collagen content and construct compliance at low pressures.
The systematic investigation of culture conditions in this research provides insights into the control of engineered blood vessel properties. The central hypothesis of this work, that grafts engineered from PGS scaffolds and adult vascular cells under biomimetic in vitro culture conditions can possess compliance comparable to autologous vessels, is true at pressures below 60 mmHg and demonstrates potential for PGS-based vascular tissue engineering. Overall, this work provides tools for engineering tubular soft tissues based on porous PGS scaffolds.
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Application of the Master Curve approach to fracture mechanics characterisation of reactor pressure vessel steelViehrig, H.-W., Kalkhof, D. January 2010 (has links)
The paper presents results of a research project founded by the Swiss Federal Nuclear Inspectorate concerning the application of the Master Curve approach in nuclear reactor pressure vessels integrity assessment. The main focus is put on the applicability of pre-cracked 0.4T-SE(B) specimens with short cracks, the verification of transferability of MC reference temperatures T0 from 0.4T thick specimens to larger specimens, ascertaining the influence of the specimen type and the test temperature on T0, investigation of the applicability of specimens with electroerosive notches for the fracture toughness testing, and the quantification of the loading rate and specimen type on T0. The test material is a forged ring of steel 22 NiMoCr 3 7 of the uncommissioned German pressurized water reactor Biblis C.
SE(B) specimens with different overall sizes (specimen thickness B=0.4T, 0.8T, 1.6T, 3T, fatigue pre-cracked to a/W=0.5 and 20% side-grooved) have comparable T0. T0 varies within the 1σ scatter band. The testing of C(T) specimens results in higher T0 compared to SE(B) specimens. It can be stated that except for the lowest test temperature allowed by ASTM E1921-09a, the T0 values evaluated with specimens tested at different test temperatures are consistent. The testing in the temperature range of T0 ± 20 K is recommended because it gave the highest accuracy. Specimens with a/W=0.3 and a/W=0.5 crack length ratios yield comparable T0. The T0 of EDM notched specimens lie 41 K up to 54 K below the T0 of fatigue pre-cracked specimens. A significant influence of the loading rate on the MC T0 was observed. The HSK AN 425 test procedure is a suitable method to evaluate dynamic MC tests. The reference temperature T0 is eligible to define a reference temperature RTTo for the ASME-KIC reference curve as recommended in the ASME Code Case N-629. An additional margin has to be defined for the specific type of transient to be considered in the RPV integrity assessment. This margin also takes into account the level of available information of the RPV to be assessed.
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Classification of fishing vessel types using machine learning methods on vessel monitoring system data / Klassificering av fiskefartygstyper med hjälp av maskininlärningsmetoder på VMS-dataMastnak, Peter January 2022 (has links)
The oceans around the world have been heavily impacted by overfishing due to very intensive commercial fishing in recent times. A large number of fish stocks have already been fully exploited. Vessel Monitoring System has been put in place to regulate fishing vessels and enforce sustainable fisheries management. Data coming from such systems can be used for the detection of illegal, unregulated, and unreported fishing. In this thesis, we present various machine learning models for the classification of fishing trip trajectories. To train these models, we develop a trajectory segmentation algorithm to create trip trajectories out of raw data and design a graphical user interface for labeling the trip trajectories into fishing and non-fishing. We also examine the impact of the temporal resolution of the data. In conclusion, the CNN-Transformer network performed the best on the binary classification of two different fishing vessel types. During the project, we realized that segmentation of real trajectory data into trips poses many problems and presents the biggest obstacle. The experiment on the varying temporal resolution of the data showed that having a higher temporal resolution gives better modeling results but only to a certain point. / Haven runt om i världen har drabbats hårt av överfiske på grund av ett mycket intensivt kommersiellt fiske på senare tid. Ett stort antal fiskbestånd har redan utnyttjats fullt ut. Fartygsövervakningssystem har införts för att reglera fiskefartyg och upprätthålla hållbar fiskeförvaltning. Data som kommer från sådana system kan användas för att upptäcka olagligt, oreglerat och orapporterat fiske. I detta examensarbete presenterar vi olika maskininlärningsmodeller för klassificering av fisketursbanor. För att träna dessa modeller utvecklar vi en segmenteringsalgoritm för att skapa turbanor av rådata och designa ett grafiskt användargränssnitt för att märka resbanorna till fiske och icke-fiske. Vi undersöker också effekten av den tidsmässiga upplösningen av datan. Sammanfattningsvis presterade CNN-Transformer-nätverket bäst i den binära klassificeringen av två olika fiskefartygstyper. Under projektet insåg vi att segmentering av verkliga bandata till resor utgör många problem och utgör det största hindret. Experimentet på den varierande tidsupplösningen av data visade att en högre tidsupplösning ger bättre modelleringsresultat men bara till en viss punkt.
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Addressing Challenges with Big Data for Maritime Navigation: AIS Data within the Great Lakes SystemDhar, Samir January 2016 (has links)
No description available.
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Utveckling av hanteringslösning för processat avloppsslam på boendeplattformar i offshore industrin / Development of a management solution for processed sewage sludge on accommodation vessels in the offshore industryJönsson, Martin January 2016 (has links)
Detta produktutvecklingsarbete har utförts i samarbete med företaget, Pegil Innovations AB. Syftet med projektet var att utveckla en hanteringslösning för processat avloppsslam (damm) på boendeplattformar i offshore industrin. Processen för projektet kombinerade Front-End processen med detaljer från Set-Based Concurrent Engineering. Projektet inleddes med en förstudie och användarstudier för att få djupare kunskap inom ämnet. Detaljer som var viktigt för projektet samlades i en kravspecifikation som användes som stöd genom hela processen. Därefter följde en idégenerering för att utforska lösningar. Från denna framkom fem idélösningar som utforskades vidare genom en fördjupning och jämförelse mot en ny kravspecifikation. Denna var en uppdaterad version av den första för att bättre reflektera vilka krav och önskemål som kunde ställas på idélösningarna. När idélösningarna hade utforskats utfördes en ny idégenerering som ledde till att idélösningarna utvecklades till två koncept. Det fördjupades kring koncepten och dessa jämfördes mot kravspecifikationen. Sedan följde ytterligare en idégenerering för att undersöka hur koncepten kunde förbättras. Slutligen utfördes ett konceptval. Resultatet blev en påse, som fästs runt en stos, som fylldes med damm och sedan sögs luften ur (för att bilda ett undertryck) samt att påsen värmeförseglades. Personalen kan sedan enkelt bära iväg påsen för att kassera denna tillsammans med dammet. / This product development project has been carried out in cooperation with the company, Pegil Innovations AB. The purpose of the project was to develop a management solution for processed sewage sludge (dust) on accommodation vessels in the offshore industry. The process of the project combined the Front-End process with details from Set-Based Concurrent Engineering. The project started with a preliminary study and user studies to obtain deeper understanding regarding the relevant knowledge area. Details that were of importance to the project was gathered in a specification that was used through the entire process as a support. Then an idea generation was preformed, to discover and explore different solutions. From the idea generation five different idea solutions were created. These five solutions were explored deeper and then compared to a new specification. The specification was an updated version from the first one to better reflect what conditions the idea solutions should meet. When the idea solutions were explored, a new idea generation was performed, resulting in two concepts. These concepts were explored deeper and then compared to a new specification. Then followed another idea generation to explore how the concepts could be improved. In conclusion to the project a concept was chosen. The result was a plastic bag which was fastened around a spigot, that was filled with the dust and then the air was withdrawn (to create a vacuum). Then the opening of the plastic bag was heat sealed. The personal could then easily carry the bag to discard this together with the dust.
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The great vessel rarely completes : translating corporate sustainabilityDai, Wenjin January 2014 (has links)
This thesis contributes to our understanding of Corporate Sustainability (CS) in Multinational Corporations (MNCs) by offering a non-western perspective. A review of the extant literature reveals CS-related studies are mainly based on theories and implications in and for western contexts. It leads us to question the definitions of CS that have been taken for granted in current management and organisation studies. This thesis argues CS should be considered as a non-fixed, contextual and culturally-sensitive notion. When the ideas of CS travel from western scholarship to Chinese organisation practices, the meanings are forever constructed, altered, and mobilised. This is beyond linguistic translation, and functions as a continuous stream of temporary hermeneutic processes of translating. This research explores how CS has been translated in a Japanese MNC in China (the organisation is called ‘OMG’ in the research). The ethnographic enquiry provides a visual and narrative representation of corporate culture as promoted in OMG; ‘Communal Vessel’ evolves as a translational construct symbolising the culturally-derived meanings of CS. The intrinsically oxymoronic meanings of ‘Communal Vessel’ can be drawn from classical Chinese philosophies, which could have implications for understanding contemporary organising practices in China, and globally. In summary, this thesis problematises the construction of CS, and contributes an indigenous, non-western way of understanding CS via an ethnographic representation focusing on processes of translating. The implications are summarised through an analysis of the classical phrase ‘The Great Vessel Rarely Completes’.
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