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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
651

Methodik zur funktionsorientierten Tolerierung mittels CAD-basierter Analysen: Methodik zur funktionsorientierten Tolerierung mittels CAD-basierterAnalysen

Berndt, Karsten, Ebermann, Marko 26 June 2015 (has links)
Teil 1 Karsten Berndt Die Festlegung von Toleranzen ist eine alltägliche Aufgabenstellung des Konstrukteurs. Dabei bedingt die Berechnung nichtlinearer Toleranzketten einen erheblichen Zeitaufwand, wodurch meist auf deren genaue Berechnung vezichtet wird und Toleranzen stattdessen auf Basis von Erfahrungswerten festgelegt werden. Die vorgestellte Methodik zeigt Wege, wie schnell und frühzeitig im Konstruktionsprozess belastbare Aussagen zu Toleranzen komplexer Mechanismen getroffen werden können. Dazu werden sogenannte Sensitivitätsanalysen in der CAD-Software "Creo Elements" durchgeführt und ausgewertet. Das Ergebnis sind erste konkrete Toleranzfelder für alle den Mechanismus beschreibenden, geometrischen Abmessungen, welche sich als Startwerte für den anschließenden Toleranzsynthese/-analyseprozess eignen. Teil 2 Marko Ebermann Dieser zweite Vortragsteil behandelt eine mögliche Vorgehensweise zur Tolerierung von Geometrieabweichungen in der frühen Entwurfsphase am Beispiel des Koppelgliedes einer Verpackungsmaschine. Ausgangspunkt für die frühe Tolerierung bildet die im ersten Vortragsteil behandelte Sensitivitätsanalyse des Koppelgetriebes, welche Informationen zur Empfindlichkeit der Funktionsmaße bezüglich der Einhaltung der Schließmaßtoleranz lieferte. Die daraus abgeleitete Form- und Lagetolerierung des Koppelgliedes soll durch anschließende Toleranzamalysen die Tolerierung im Baugruppenkontext bestätigen und auf möglich Fertigungsverfahren abzielen, ohne die genaue Gestalt der Komponenten zu kennen. So können teure und zeitintensive Iterationsschleifen im Konstruktionsprozess minimiert und die Funktionalität frühzeitig gesichert werden.
652

Oven Usage Optimization : A study on scheduling at the wear edge production at Olofsfors AB / Optimering av ugnsanvändning : En studie av slitstålproduktionen hos Olofsfors AB

Karlsson, Anna January 2023 (has links)
Olofsfors is a steel product manufacturer in Nordmaling, Sweden, producing steel edges for snowplows, tracks for forest machines, and wear edges for buckets on heavy equipment. Most of their products are heated to 900◦ C and then cooled down in water, so-called quenching, during the hardening process. A group of ovens and quench machines together form an oven system and this is used for the hardening. Since it takes a long time for the ovens to reach operating temperature, they are always kept on, which is why it is important to utilize them as effectively as possible. This project investigates the potential utilization increase of one of the three oven systems in the wear edge production unit. This oven system is part of a production line that consists of a saw and a mill, and can process products up to two meters in length, and is hereon called the two-meter line. The two-meter line has a natural inflow through the saw, but raw material produced in other parts of the factory can also be fetched from another inlet. The use of the other inlet is limited by the operator of the two-meter line who has to fetch the material with a forklift. This could be automated so that the operator would not have to handle this inlet. The purpose is to investigate the potential increases in utilization of the oven system for different degrees of automation in order to make the most of the machines and the operator at the two-meter line. In the end, a recommendation is given with a set of ideal properties of the investment that could improve productivity the most. The main method applied in order to explore the potential use of the oven system is a re-entrant flow shop scheduling model. As preceding steps, the production line is first mapped in order to find potential routes for different product families, then the order quantities in the production data are translated into jobs to be scheduled with the help of packing problems and batching rules. The scheduling model of the production line is then solved heuristically with a genetic algorithm based on the sequence of jobs entering the production line followed by a method for creating a deterministic schedule based on this initial sequence of jobs. Lastly, a sensitivity analysis is applied to the processing time for the steps performed by the operator to evaluate the results' robustness. The conclusion is that there is a substantial potential to increase the utilization of the oven system of the two-meter line. The largest potential is when the operator is not actively working at the production line; a maximum of 15.6 h on average. There does also exist a potential to increase utilization while the operator is working at the production line; a maximum of 3.9 h on average. The automation degree needed is high in both cases but due to different reasons. When the operator is not working, the automatic solution needs to work without supervision for longer periods of time, while, in the other case, it needs to be smart enough to adjust to not disturb the operator’s work. For the future, the recommendation is to focus the next step on finding investment options that could exploit the time when the operator is not working. By further specifying the potential investment alternatives, the cost factor can be added to the analysis as well. / Olofsfors AB är en stålproduktstillverkare i Nordmaling, Sverige, som producerar vägstål till bland annat snöplogar, band till skogsmaskiner och slitstål till entreprenadmaskiner. De flesta av deras produkter hettas upp till 900 C och släcks sedan i vatten under härdningsprocessen. En grupp av ugnar och härdmaskiner kallas tillsammans för ett ungsystem och det används till härdningen. Eftersom det tar lång tid att värma upp ugnarna står de alltid på-slagna och det är därför viktigt att använda dem så effektivt som möjligt.  I detta projekt har potentialen att öka användandet av ett av tre ugnsystem i slitstålsproduktionen undersökts.  Ugnsystemet i fråga är en del av en produktionslinje som också består av en såg och en fräs och kan härda artiklar med längder upp till två meter och kallas därför här tvåmeterslinjen. Den naturliga ingången för råmaterial i produktionslinjen är genom sågen, men det finns även en alternativ ingång för råmaterial som förbehandlats i tidigare produktionssteg i fabriken. Användandet av den andra ingången till produktionlinjen begränsas av att operatören i produktionslinjen måste hämta materialet med truck. Detta in-flöde skulle gå att automatisera så att operatören inte skulle behöva hämta dessa artiklar.  Syftet är att undersöka det potentiella ökade nyttjandet av ugnsystemet för olika grader av automation för att bäst använda maskiner och operatör i tvåmeterslinjen. I slutet ges en rekommendation gällande vilka egenskaper investeringen bör ha för att öka produktiviteten mest.  Huvudmetoden för att undersöka möjligt ökat nyttjande av ugnarna är en schemaläggningsmodel. Som underliggande steg kartläggs först produktionslinjen och de olika rutter som olika produktfamiljer tar genom produktionslinjen. Produktkvantiteterna för varje order i produktionsdatan omvandlas sedan till jobb som kan schemaläggas genom packningsproblem och regler för laststorlekar i de olika maskinerna. Schemaläggningsmodellen löses sedan heuristiskt med hjälp av en genetisk algoritm som bestämmer den initiala sekvensen av jobben i första steget, tillsammans med en deterministisk metod för att skapa ett helt schema baserat på den initiala sekvensen av jobben. Slutligen genomförs en känslighetsanalys på processtiderna för steg som motsvarar operatören för att undersöka hur robust resultatet är.    Slutsatsen är att det finns en stor potential att öka nyttjandet av ugnsystemet i tvåmeterslinjen. Den största potentialen är när operatören inte arbetar aktivt vid produktionslinjen, med ett maximum på ca 15,6 h per dag. Det finns också en möjlighet att utöka nyttjandet av ugnarna under tiden som operatören arbetar aktivt med ordrar och outnyttjad tid då är 3,9 h i genomsnitt. Graden av automation är hög oberoende av vilken tid som ska utnyttjas men på grund av olika anledning. Om tiden då operatören inte aktivt jobbar utnyttjas, måste den automatiserade lösningen fungera autonomt under längre tid. Om den istället förväntas fungera parallellt med operatören måste den anpassas smart så att den inte stör operatörens arbete och flöde. Rekommendationen är att fokusera på att hitta konkreta investeringsalternativ som utnyttjar tiden då operatören inte aktivt arbetar för att få bättre kostnadsunderlag att ha med i den vidare analysen.
653

TECHNO-ECONOMIC ANALYSIS OFRENEWABLE GAS PRODUCTION AND ELECTRICITY GENERATION FROM ORGANIC WASTE : A Feasibility Study of a Conceptual Biogas Plant in the Santander Region, Colombia

Sassersson Busadee, Nelly, Ahmed, Laura January 2023 (has links)
Strategies to harness the energy from organic waste is gaining importance on a global scale, especially in countries with large quantities of it. In this paper, a techno-economic analysisand a field study were performed to investigate the feasibility of five scenarios for a conceptual biogas facility, based on a case study from Colombia. The plant designs involved anaerobic digestion followed by different combinations of biogas upgrading, combined heat and power and/or steam methane reforming technologies and investigated four different feedstocks. The results demonstrated that the road infrastructure leading to the current proposed site is inadequate, and a new location should be found. Anaerobic digestion alone was most profitable with the shortest payback period. Organic Municipal Solid Waste and Poultry Manure produced high techno-economic potential depending on the scenario. The production of hydrogen using anaerobic digestion, steam methane reforming and combined heat and power with or without upgrading is not recommended due to the current market prices and high heat consumption. However, it can be profitable to implement green energy initiatives as a strategy to establish and lead future energy markets.
654

[pt] ANÁLISE DE SENSIBILIDADE NA MODELAGEM 2D DA CONTENÇÃO DE FRATURAS HIDRÁULICAS / [en] SENSITIVITY ANALYSIS IN 2D MODELING OF HYDRAULIC FRACTURE CONTAINMENT

RAFAEL FONSECA DE MESQUITA 29 December 2021 (has links)
[pt] Este trabalho faz uma análise da variação dos parâmetros que têm importância na propagação de fraturas hidráulicas e da influência desses parâmetros na conten-ção do fraturamento. Os experimentos numéricos foram feitos em um modelo 2D utilizando um simulador de elementos finitos com acoplamento sequencial hidro-dinâmico, tendo como premissa o comportamento dos processos envolvidos em es-tado estacionário. Inicialmente foram feitos testes de validação das soluções numé-ricas empregadas neste trabalho a partir de casos cujas soluções são bem conheci-das. Então, efeitos de variações de poropressão, de estado de tensões, propriedades das rochas, intervalos de início da fratura hidráulica, efeitos térmicos e o dano à permeabilidade da formação permoporosa foram utilizados para avaliar a contenção da fratura hidráulica. Primeiramente os efeitos foram avaliados separadamente e, em seguida, foram combinados aos pares, por meio de sorteio, e então avaliados. Os estudos levaram à conclusão de que o fator de maior influência para o início da propagação da fratura hidráulica na rocha capeadora (primeiros metros) é o valor da tensão mínima de confinamento do reservatório e a continuidade da propagação vertical na rocha selante é dominada pelo contraste de tensões entre rochas reserva-tório e capeadora. Entretanto, os demais parâmetros exercem influência na conten-ção do fraturamento hidráulico e devem ser levados em consideração neste tipo de estudo, principalmente os que servirão de insumo para a tomada de decisões. / [en] This master thesis analyzes the parameter s variation on the hydraulic frac-ture s propagation importance and the influence of these parameters on fracture containment. The numerical experiments were performed in a 2D model using a finite element simulator with sequential hydrodynamic coupling, having the sta-tionary behavior of the processes involved as premise. Validation tests were ini-tially performed for the numerical solutions used in this thesis from cases which solutions are well known. Then, effects of pore pressure variations, stress state, rock properties, hydraulic fracture opening intervals, thermal effects, and damage to the permoporous formation were used to evaluate the hydraulic fracture containment. At first, the effects were evaluated separately, then sorted for pair combinations, so they could be analyzed. These analyzes led to the conclusion that the most influen-tial factor for the hydraulic fracture initial propagation in the cap rock (first meters) is the reservoir’s minimum confinement stress value, and the vertical propagation continuity in the sealing rock is dominated by the stress contrast between reservoir and cap rocks. However, other parameters influence the hydraulic fracturing con-tainment and should be considered for this type of study, especially those that will serve as input for decision-making.
655

[en] DRILL STRING VIBRATIONS IN SOLIMÕES BASIN OPERATIONS / [pt] VIBRAÇÕES EM COLUNAS DE PERFURAÇÃO EM OPERAÇÕES NA BACIA DO SOLIMÕES

PAULO ALBERTO DA COSTA MATTOS 28 January 2016 (has links)
[pt] Os custos de uma campanha exploratória, incluindo a perfuração de poços de petróleo estão cada vez mais elevados. As vibrações nas colunas de perfuração estão presentes a todo momento nas operações de perfuração, o que podem ocasionar a quebra destas colunas e do BHA (Bottom Hole Assembly), danos em brocas e demais equipamentos. Além do custo do possível dano e/ou perda destes equipamentos, existem os custos da sonda parada e a despesas operacionais das companhias contratadas, o chamado custo de Stand by, e o mais indesejável, a perda do poço. Fenômenos como Bit Bounce, Stick-Slip e Forward/Backward Whril, que advém das vibrações axiais, torcionais e laterais respectivamente, são motivos de vários estudos. Esta dissertação pretende fazer a validação do modelo matemático de dinâmica torcional utilizado na dissertação de mestrado de CAYRES (2013) para gerar mapas de estabilidade para vibrações torcionais. Nesta dissertação parâmetros reais de uma coluna de perfuração foram inseridos no modelo com objetivo de obter mapas de estabilidade de vibrações torcionais para a perfuração de um poço na Bacia de Solimões. Tais mapas de estabilidade foram gerados a partir deste modelo matemático, que na tese de CAYRES (2013), é baseado em procedimento experimental, com um atrito não linear induzindo o fenômeno stick-slip que está associado às vibrações torcionais. Este fenômeno tem relação entre torque e velocidade angular na broca provocando vibrações indesejáveis na coluna de perfuração. A geração destes mapas permitiu que a análise de sensibilidade e a averiguação da ocorrência ou não de vibrações torcionais fossem feitas, bem como a inserção de valores de WOB (peso sobre a broca) e RPM (velocidade de rotação) de um caso real de perfuração de um poço na Bacia do Solimões. Nesta análise de sensibilidade foram considerados, além dos aspectos acima citados, o tipo de broca e formação geológica, permitindo assim a validação do modelo de CAYRES (2013) e contribuindo para a otimização dos processos operacionais da perfuração de poços de petróleo. / [en] The costs of an exploration campaign, including the drilling of oil wells are increasingly high. The vibrations in the drill strings are present at all times in drilling operations that can cause damage of these drill pipe and BHA (Bottom Hole Assembly), as drill bits and other equipment. Besides the cost of a possible damage or loss of such equipment, there are the costs when the rig is not operating and the expenses of all companies involved in the operations, called the cost of stand by, and the worst case scenario of the undesirable loss of the well. The Phenomena like Bit Bounce, Stick-Slip and Forward/Backward Whril, that arises from axial, torsional and lateral vibrations respectively are the motivation of several studies. This dissertation aims to show the validation of the mathematical modeling of the torsional dynamics used in CAYRES (2013) that generate stability maps for torsional vibrations. In this dissertation real parameters from a drill string were inserted in this mathematical modeling, aiming to obtain stability maps for torsional vibrations during a drilling operation of a well in Solimões Basin. Such stability maps were generated from a dynamic model that in CAYRES (2013) thesis is based on an experimental procedure with a nonlinear friction inducing stick-slip phenomenon associated to torsional vibrations. This phenomenon is related to torque and angular velocity on the bit generating undesirable vibrations. Build stability maps and checking when torsional vibrations happen, and then comparing with a real case of WOB (weight on bit) and RPM (rotary speed) in Solimões Basin. In this sensitivity analysis were considered, besides the aspects mentioned above, the kind of bit and geological formation in order to contribute to the optimization of the oil well drilling operational process.
656

Causal Inference for Observational Survival Data using Restricted Mean Survival Time Model

Lin, Zihan 09 December 2022 (has links)
No description available.
657

Evolution and phylogeny of basal winged insects with emphasis on mayflies (Ephemeroptera)

Ogden, Thomas H. 29 November 2004 (has links) (PDF)
Ephemeroptera (mayflies) is a monophyletic group of semi-aquatic pterygote insects, comprising 3083 species, 376 genera, and 37 described families and are present on all continents, excluding Antarctica, being associated with freshwater and brackish water habitats. The order is unique among pterygote insects in possessing functional wings at the penultimate molt (subimago stage), prior to the full development of genitalia; in all other insects the presence of functional wings occurs only after the final molt. The purpose of this dissertation is to use molecular and morphological data, in order to investigate the position of the order Ephemeroptera among other insect orders, the higher-level relationships among the major lineages of mayflies, and a detailed analysis of the family Ephemerellidae. Ephemeroptera has been considered by many to be sister to Odonata + Neoptera although alternate hypotheses have been suggested. Data from three molecular loci ambiguously resolve basal pterygote relationships, however, total evidence analysis (combined molecular and morphological data) strongly supports the position of mayflies as sister to all other extant pterygotes. These results and methodologies were recently criticized, and, therefore, the response to the author is included following the manuscript. The phylogenetic relationships among mayfly families is debatable and in some groups unknown. Prior studies have produced phylogenies based on morphological characters mixed with intuition. The first molecular phylogeny for the Order Ephemeroptera is presented. The analyses include 31 of the 37 families, representing ~24% of the genera. The suborders Furcatergalia and Carapacea are supported as monophyletic while Setisura and Pisciforma are not supported as monophyletic. The evolution of the wings, mandibular tusks, burrowing lifestyle, and fishlike body are investigated. Topological sensitivity analysis is used as a tool to examine patterns concerning the stability of relationships across a parameter landscape, providing additional information that may not have been acquired otherwise. The Pannote family Ephemerellidae is comprised of 16 genera and over 300 species and is distinguished from other mayfly families by the absence of the second pair of abdominal gills. The position of Ephemerellidae relative to other closely related pannote mayflies is unclear as are the relationships of the genera within the family. The combined molecular and morphological analyses resulted in a monophyletic Ephemerellidae as sister to the other ephemerelloid families. The subfamily Ephemerellidae was supported as monophyletic, while Timpanoginae had conflicting results.
658

Exploration of implicit weights in composite indicators : The case of resilience assessment of countries’ electricity supply

Lindén, David January 2018 (has links)
Composite indicators, also called indices, are widely used synthetic measures for ranking and benchmarking alternatives across complex concepts. The aim of constructing a composite indicator is, among other things, to simplify and condense the information of a plurality of underlying indicators. However, to avoid misleading results, it is important to ensure that the construction is performed in a transparent and representative manner. To this end, this thesis aims to aid the construction of the Electricity Supply Resilience Index (ESRI) – which is a novel energy index, developed within the Future Resilient Systems (FRS) programme at the Singapore-ETH Centre (SEC) – by looking at the complementary and fundamental component of index aggregation, namely the weighting of the indicators. Normally, weights are assigned to reflect the relative importance of each indicator, based on stakeholders’ or decision-makers’ preferences. Consequently, the weights are often perceived to be importance coefficients, independent from the dataset under analysis. However, it has recently been shown that the structure of the dataset and correlations between the indicators often have a decisive effect on each indicator’s importance in the index. In fact, their importance rarely coincides with the assigned weights. This phenomenon is sometimes referred to as implicit weights. The aim of this thesis is to assess the implicit weights in the aggregation of ESRI.  For this purpose, a six-step analytical framework, based on a novel variance-based sensitivity analysis approach, is presented and applied to ESRI. The resulting analysis shows that statistical dependencies between ESRI’s underlying indicators have direct implications on the outcome values – the equal weights assigned a-priori do not correspond to an equal influence from each indicator. Furthermore, when attempting to optimise the weights to balance the contribution of each indicator, it is found that this would require a highly unbalanced set of weights and come at the expense of representing the indicators in an effective manner. Thereby, it can be concluded that there are significant dependencies between the indicators and that their correlations need to be accounted for to achieve a balanced and representative index construction. Guided by these findings, this thesis provides three recommendations for improving the statistical representation and conceptual coherence of ESRI. These include: (1) avoid aggregating a negatively correlated indicator – keep it aside, (2) remove a conceptually problematic indicator – revise its construction or conceptual contribution, and (3) aggregate three collinear and conceptually intersecting indicators into a sub-index, prior to aggregation – limit their overrepresentation. By revising the index according to these three recommendations, it is found that ESRI showcases a greater conceptual and statistical coherence. It can thus be concluded that the analytical framework, proposed in this thesis, can aid the development of representative indices. / Kompositindikatorer (eller index) är populära verktyg som ofta används vid rankning och benchmarking av olika alternativ utifrån komplexa koncept. Syftet med att konstruera ett index är, bland annat, att förenkla och sammanfatta informationen från ett flertal underliggande indikatorer. För att undvika missvisande resultat är det därmed viktigt att konstruera index på ett transparent och representativt sätt. Med detta i åtanke, avser denna uppsats att stödja konstruktionen av Electricity Supply Resilience Index (ESRI) – vilket är ett nyutvecklat energiindex, framtaget inom Future Resilient Systems (FRS) programmet på Singapore-ETH Centre (SEC). Detta görs genom att studera ett vanligt fenomen (s.k. implicita vikter) som gör sig gällande i ett av konstruktionsstegen, då de underliggande indikatorerna ska viktas och aggregeras till ett index. I detta steg tilldelas vanligtvis vikter till de enskilda indikatorerna som ska spegla deras relativa betydelse i indexet. Det har dock nyligen visats att datastrukturen och korrelationer mellan indikatorerna har en avgörande påverkan på varje indikators betydelse i indexet, vilket ibland kan vara helt oberoende av vikten de tilldelats. Detta fenomen kallas ibland för implicita vikter, då de ej är explicit tilldelade utan uppkommer från datastrukturen. Syftet med denna uppsatts är således att undersöka de implicita vikterna i aggregationen av ESRI.  För detta ändamål sker en tillämpning och utökning av en nyutvecklad variansbaserad känslighetsanalys, baserad på olinjär regression, för bedömning av implicita vikter i kompositindikatorer. Resultaten från denna analys visar att statistiska beroenden mellan ESRIs underliggande indikatorer har direkt inverkan på varje indikators betydelse i indexet. Detta medför att vikterna ej överensstämmer med indikatorernas betydelse. Följaktligen utförs en vikt-optimering, för att balansera bidraget från varje indikator. Utifrån resultaten av denna vikt-optimering kan det konstateras att det inte är tänkbart att balansera bidraget från varje indikator genom att justera vikterna. Om så görs, skulle det ske på bekostnad av att kunna representera varje indikator på ett effektivt sätt. Därmed kan slutsatsen dras att det finns tydliga beroenden mellan indikatorer och att deras korrelationerna måste tas i hänsyn för att uppnå en balanserad och representativ indexkonstruktion. Utifrån dessa insikter presenteras tre rekommendationer för att förbättra den statistiska representationen och konceptuella samstämmigheten i ESRI. Dessa innefattar: (1) Undvik att aggregera en negativt korrelerad indikator - behåll den vid sidan av, (2) ta bort en konceptuellt problematisk indikator - revidera dess konstruktion eller konceptuella bidrag, och (3) sammanställ tre kollinära och konceptuellt överlappande indikatorer i ett sub-index, före aggregering - begränsa deras överrepresentation. När dessa rekommendationer implementerats står det klart att den reviderade ESRI påvisar en förbättrad konceptuell och statistisks samstämmighet. Därmed kan det fastställas att det analytiska verktyg som presenteras i denna uppsats kan bidra till utvecklingen av representativa index.
659

Criticality and Risk Assessment for Pipe Rehabilitation in the City of Santa Barbara Sewer System

Rossi, Rossi Carmelo, II 01 June 2015 (has links) (PDF)
Aging sewer infrastructure is posing greater and greater risk to the health and well-being of City residents. Issues can range from pipe blockages in sewer laterals to Sanitary Sewer Overflows. This thesis develops a risk analysis method that can be used by municipalities to maintain and rehabilitate sewer assets. Risk combines the effect of Likelihood of Failure (LOF) and Consequence of Failure (COF) to perform a complete two-dimensional analysis that allows for relative comparison between different pipes in the system. The LOF rating has been equated to pipe integrity while the COF rating was related to the environmental, economic, and social consequences to pipe failure. In order to estimate pipe integrity Closed Circuit Television (CCTV) scores from the City of Santa Barbara were used in combination with spatial and physical properties associated with each pipe. The CCTV scores were simply integer values between 0 and 5 based on the National Association of Sewer Services Company’s (NASSCO) Pipeline Assessment Certification Program (PACP) results. The quantitative parameters included pipe material and age, distance from restaurants, distance from any above ground water source, pipe depth below the ground surface, pipe length, and vehicular traffic volumes. The sensitivity analysis compared the given structural integrity scores with the predicted scores based on the weighted scoring method. It isolated four out of six of the parameters tested that affected the structural integrity of sewer pipes: material and age (45%), pipe depth (20%), Vehicular Traffic (10%), and distance from an above-ground water source (25%). A program was created in the C programming language that iteratively determined the percentage for each factor. These percentage factors are used to obtain the predicted structural integrity score for all the pipes. Like the LOF rating, the COF rating consisted of scores between 0 and 5. The COF rating used pipe diameter, distance from commercial zones, distance from critical infrastructure, and vehicular traffic volume as parameters for quantifying the environmental, economic, and social consequences. These factors were determined from review of past literature and given approximately equal weighting when determining the COF rating values. The environmental factor, pipe diameter, was given a percentage factor of 30%; the economic factor, distance to commercial zones, was given a percentage factor of 30%; and the social concerns, distance to critical infrastructure and vehicular traffic volume, were given percentage factors of 20% each. Finally, the risk for each pipe was determined in Geographic Information Systems (GIS) by combining the predicted structural integrity score or LOF rating and COF rating value for each pipe. This generated color-coded maps that showed distinct pipes that had the most critical predicted structural integrity scores, highest consequence, and the pipes with the most risk. This process could be used by any City to create a maintenance and rehabilitation schedule and plan for future CCTV inspections.
660

Perturbed Optimal Control for Connected and Automated Vehicles

Gupta, Shobhit January 2022 (has links)
No description available.

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