The present work makes a study of the drag forces of umbilical cables of pipes inspection robots and aims to determine a valid model for their calculation. For this purpose, the physical models are developed in relation to the friction forces for the straight and curved sections in all their possible configurations, obtaining for each case a differential equation that models the friction phenomenon and that includes fluid and cable the characteristics. By solving the differential equation, an explicit expression is obtained for the value of the frictional force in each case. In the present work, the obtained model is evaluated in comparison with the traditional simplified model. It is also presented a study about the influence of the stiffness of the cable and how this characteristic generates the forces of the normal general forces at the ends of the curves that, finally, result in an additional component of the frictional forces. By comparison with actual drag force measurements, the model obtained is validated. The complexity of the calculations required for the determination of the pull forces in real pipes makes it necessary to use software tools to facilitate it. For this reason, two software applications are developed, one specific for rigid pipes and another one for flexible pipes. A series of strategies of how to keep low the maximum value of the cable tension are presented too. / El presente trabajo se dedica al estudio de fuerzas de arrastre de cables umbilicales de robot de inspección o desobstrucción de tuberías y tiene como objetivo la determinación de un modelo válido para el cálculo de las mismas. Para tal fin, se desarrollan los modelos físicos en relación a las fuerzas de rozamiento presentes para tramos rectos y curvas en todas sus configuraciones posibles, obteniéndose así, para cada caso, una ecuación diferencial que modela el fenómeno del rozamiento y que incluye las variables propias del fluido presente y las características pertinentes del cable. Mediante la resolución de esa ecuación diferencial, se obtiene una expresión explícita para el valor de la fuerza de rozamiento en cada caso. En el presente trabajo, el modelo obtenido es evaluado mediante comparación con el modelo simplificado tradicional de manera de ver los alcances del nuevo modelo. Se realiza también una presentación de la influencia que tiene la rigidez del cable y como esta rigidez a la flexión genera fuerzas normales adicionales en los extremos de las curvas que redundan finalmente en una componente adicional de las fuerzas de fricción. Mediante comparación con mediciones reales de fuerza de arrastre se valida el modelo obtenido Dada la complejidad de los cálculos requeridos para la determinación de las fuerzas de arrastre de tuberías reales se desarrollan dos aplicaciones de software para el cálculo de las mismas, una específica para tuberías rígidas y otra para tuberías flexibles utilizando algoritmos de cálculo basados en las ecuaciones determinadas. Son presentadas también, una serie de estrategias de forma de mantener acotado el valor máximo de la tensión de cable. Dentro de las estrategias están la elección de materiales de recubrimiento de cable que presenten un bajo coeficiente de fricción con la tubería, la adopción de cables cuyo peso específico sea tal que el peso se iguale a la fuerza de empuje y la incorporación de varios dispositivos de tracción del cable de modo de mantener bajas las contra tensiones del cable utilizando un sistema distribuido de empuje.

The recent substantial increase in world demand for energy and raw material resources has accelerated oil and gas exploration and production. At the same time, the depletion of onshore and shallow water oil resources presents a challenge to engineers to develop new means of harvesting and transporting oil and gas from harsh and remote areas. Sandwich Pipe (SP) is a relatively new design concept developed to address the transportation of oil in deep and ultra-deep waters as well as in cold environments. The main focus of this thesis is on the characterization of the structural performance of these novel systems. Deep and ultra-deep water offshore pipelines are subjected to excessive hydrostatic external pressure during installation and operation. In this research, an innovative analytical solution was developed to evaluate the external pressure capacity of SPs by calculating the linear eigenvalues of the characteristic equations of the system. In the proposed solution, the interface condition between the layers of the system is accounted for in the governing equations. As well, a set of comprehensive parametric studies using the Finite Element (FE) method was developed to investigate both the elastic and plastic buckling response of SPs. The influence of various structural parameters such as the material, geometrical and intra-layer interaction properties on the characteristic behavior and the buckling pressure of SPs was examined. In addition to the proposed analytical solution, two sets of semi-empirical equations based on the FE analysis results were recommended in calculating the elastic and plastic buckling pressure of SPs. As bending represents an important loading state in the installation and service life of SPs, it should be considered a governing loading scenario. In this thesis, the behavior of SPs under bending was investigated using a comprehensive set of parametric studies. SP systems with a wide practical range of physical parameters were analyzed using the FE method, and the influence of various structural parameters on the characteristic response and bending capacity of the system was explored, including pipe geometry, core layer properties, material yield anisotropy of high-grade steel pipes, and various intra-layer adhesion configurations.

The present work makes a study of the drag forces of umbilical cables of pipes inspection robots and aims to determine a valid model for their calculation. For this purpose, the physical models are developed in relation to the friction forces for the straight and curved sections in all their possible configurations, obtaining for each case a differential equation that models the friction phenomenon and that includes fluid and cable the characteristics. By solving the differential equation, an explicit expression is obtained for the value of the frictional force in each case. In the present work, the obtained model is evaluated in comparison with the traditional simplified model. It is also presented a study about the influence of the stiffness of the cable and how this characteristic generates the forces of the normal general forces at the ends of the curves that, finally, result in an additional component of the frictional forces. By comparison with actual drag force measurements, the model obtained is validated. The complexity of the calculations required for the determination of the pull forces in real pipes makes it necessary to use software tools to facilitate it. For this reason, two software applications are developed, one specific for rigid pipes and another one for flexible pipes. A series of strategies of how to keep low the maximum value of the cable tension are presented too. / El presente trabajo se dedica al estudio de fuerzas de arrastre de cables umbilicales de robot de inspección o desobstrucción de tuberías y tiene como objetivo la determinación de un modelo válido para el cálculo de las mismas. Para tal fin, se desarrollan los modelos físicos en relación a las fuerzas de rozamiento presentes para tramos rectos y curvas en todas sus configuraciones posibles, obteniéndose así, para cada caso, una ecuación diferencial que modela el fenómeno del rozamiento y que incluye las variables propias del fluido presente y las características pertinentes del cable. Mediante la resolución de esa ecuación diferencial, se obtiene una expresión explícita para el valor de la fuerza de rozamiento en cada caso. En el presente trabajo, el modelo obtenido es evaluado mediante comparación con el modelo simplificado tradicional de manera de ver los alcances del nuevo modelo. Se realiza también una presentación de la influencia que tiene la rigidez del cable y como esta rigidez a la flexión genera fuerzas normales adicionales en los extremos de las curvas que redundan finalmente en una componente adicional de las fuerzas de fricción. Mediante comparación con mediciones reales de fuerza de arrastre se valida el modelo obtenido Dada la complejidad de los cálculos requeridos para la determinación de las fuerzas de arrastre de tuberías reales se desarrollan dos aplicaciones de software para el cálculo de las mismas, una específica para tuberías rígidas y otra para tuberías flexibles utilizando algoritmos de cálculo basados en las ecuaciones determinadas. Son presentadas también, una serie de estrategias de forma de mantener acotado el valor máximo de la tensión de cable. Dentro de las estrategias están la elección de materiales de recubrimiento de cable que presenten un bajo coeficiente de fricción con la tubería, la adopción de cables cuyo peso específico sea tal que el peso se iguale a la fuerza de empuje y la incorporación de varios dispositivos de tracción del cable de modo de mantener bajas las contra tensiones del cable utilizando un sistema distribuido de empuje.

The present work makes a study of the drag forces of umbilical cables of pipes inspection robots and aims to determine a valid model for their calculation. For this purpose, the physical models are developed in relation to the friction forces for the straight and curved sections in all their possible configurations, obtaining for each case a differential equation that models the friction phenomenon and that includes fluid and cable the characteristics. By solving the differential equation, an explicit expression is obtained for the value of the frictional force in each case. In the present work, the obtained model is evaluated in comparison with the traditional simplified model. It is also presented a study about the influence of the stiffness of the cable and how this characteristic generates the forces of the normal general forces at the ends of the curves that, finally, result in an additional component of the frictional forces. By comparison with actual drag force measurements, the model obtained is validated. The complexity of the calculations required for the determination of the pull forces in real pipes makes it necessary to use software tools to facilitate it. For this reason, two software applications are developed, one specific for rigid pipes and another one for flexible pipes. A series of strategies of how to keep low the maximum value of the cable tension are presented too. / El presente trabajo se dedica al estudio de fuerzas de arrastre de cables umbilicales de robot de inspección o desobstrucción de tuberías y tiene como objetivo la determinación de un modelo válido para el cálculo de las mismas. Para tal fin, se desarrollan los modelos físicos en relación a las fuerzas de rozamiento presentes para tramos rectos y curvas en todas sus configuraciones posibles, obteniéndose así, para cada caso, una ecuación diferencial que modela el fenómeno del rozamiento y que incluye las variables propias del fluido presente y las características pertinentes del cable. Mediante la resolución de esa ecuación diferencial, se obtiene una expresión explícita para el valor de la fuerza de rozamiento en cada caso. En el presente trabajo, el modelo obtenido es evaluado mediante comparación con el modelo simplificado tradicional de manera de ver los alcances del nuevo modelo. Se realiza también una presentación de la influencia que tiene la rigidez del cable y como esta rigidez a la flexión genera fuerzas normales adicionales en los extremos de las curvas que redundan finalmente en una componente adicional de las fuerzas de fricción. Mediante comparación con mediciones reales de fuerza de arrastre se valida el modelo obtenido Dada la complejidad de los cálculos requeridos para la determinación de las fuerzas de arrastre de tuberías reales se desarrollan dos aplicaciones de software para el cálculo de las mismas, una específica para tuberías rígidas y otra para tuberías flexibles utilizando algoritmos de cálculo basados en las ecuaciones determinadas. Son presentadas también, una serie de estrategias de forma de mantener acotado el valor máximo de la tensión de cable. Dentro de las estrategias están la elección de materiales de recubrimiento de cable que presenten un bajo coeficiente de fricción con la tubería, la adopción de cables cuyo peso específico sea tal que el peso se iguale a la fuerza de empuje y la incorporación de varios dispositivos de tracción del cable de modo de mantener bajas las contra tensiones del cable utilizando un sistema distribuido de empuje.

During the so-called “Miljonprogrammet”, over a million homes were built in Stockholm. As the buildings mature, parts of the buildings reach their technical life times and it is time to renovate them. At a time when the environmental impact of humans is a hot topic, it is appropriate to take the environment into account when deciding upon which restoration method to use. The sewage pipes are one of the important building parts in need of repair. This can be achieved by for example traditional pipe replacement or Cure-In-Place-Pipes (CIPP-lining).The goal of this study is to investigate and compare the environmental impact of traditional pipe replacement versus the use of the relining method CIPP lining by conducting a comparative life cycle assessment (LCA). The methods differ in the way that traditional pipe replacement demolishes the outer layers of the bathrooms and remove the old pipes to replace with new and restore the surface layers while CIPP-lining renovates the pipes from the inside with the use of a flexible liner.The purpose of the study has been to clarify the differences in environmental impacts of the different methods in a clear and easily understood way and thereby also simplify the decision-making process of property owners in need of renovation.With aid of the guidelines in ISO standards 14040 and 14044 a correct methodology has been used to ensure that the level of this work will be as high as possible. In combination with the software SimaPro specifically developed to handle the creation of various forms of life cycle assessments and the ISO standards a complex system been analyzed in detail.The results of the study show that CIPP-lining generally cause less environmental impacts than the traditional pipe replacement method. The analysis of 14 selected impact categories show that CIPP lining is preferable in 13 categories and that the traditional pipe replacement is preferable in 1 category. The sensitivity analysis show that the results change drastically depending on how much of the materials and energy used to demolish and reconstruct the outer layers of the bathroom one chooses to allocate to the new sewer pipes.The results show that the CIPP-lining results are dependent on the consumables and the liner assembly processes while the energy usage of the production process does not have a large impact on the results. For the traditional pipe replacement the results show that the consumable process is clearly the biggest impact while the piping production inflicts the least impact on the result.

No description available.

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Computational Fluid Dynamics (CFD) has become one of the main instruments for the prediction of many commercial and research oriented fluid flow and heat transfer problems. While single phase flow analysis through CFD has gained grounds within the commercial industry, multiphase flow analysis is still the subject of further research and development. Heat Pipes and thermosyphones are no exception to this. However, the involvement of more than one fluid phase within these devices has made their analysis through CFD more challenging and computationally more demanding to perform. In this thesis, computational fluid dynamics is used as a modelling tool in order to predict the thermal hydraulic behaviour of multiphase environment within thermosyphones and heat pipes. Eulerian two-fluid method is used to solve the conservation equations for mass, momentum and energy, for each phase along with the inclusion of interfacial heat and mass transfer terms. Numerical predictions are obtained for the steady-state and transient operation of stationary thermosyphon, while rotating heat pipes operation is also simulated using axially and radially rotating heat pipe models. Apart from using the commercially available CFD code for the analysis of thermosyphones related simulation, numerical work is performed regarding the coupling of momentum equations based on Eulerian two-fluid modelling scheme. OPENFOAM open source code is used and modified to include the Partial Elimination Algorithm (PEA) for the coupling of interfacial exchange terms, including interfacial mass transfer term, in the momentum equations of both phases. Results obtained from above discussed studies provide good agreement with corresponding experimental and analytical observations.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

Gerald Near's Chantworks has pedagogical value for the intermediate-level organ student seeking to attain advanced-level skills. Chantworks, composed for organ solo, is a collection of twenty-three pieces of short to moderate duration, based upon Gregorian chants. Gerald Near is an established composer who has won awards, completed numerous commissions, and published a multitude of organ and choral works. The Chantworks pieces are analyzed for their usefulness in the development of the following skills: (1) the advanced use of the expression pedal; (2) advanced manual changes and registration changes; (3) voice-crossing; and (4) the ability to play Gregorian chants with rhythmic sensitivity and appropriate phrase shaping. The study highlights the particular usefulness of Near's collection by comparing its technical demands to selected organ instructional books and musical collections that have been identified as having pedagogical value. This study provides a definition of an "intermediate organist," listing techniques acquired from the successful completion of any of the selected organ pedagogy publications. An examination of selected organ pedagogy publications addresses several techniques characteristic of pipe organ performance mastery that are not emphasized in the method books, but that would be necessary for an organist to acquire in order to tackle the more difficult works of the organ literature. Musical examples and explanations will illustrate how these other techniques can be learned and practiced in a structured manner through the study of pieces from Gerald Near's Chantworks collection. Several pieces within Chantworks contain passages that have pedagogical bearing on aspects of general musicianship, such as irregular meters and cross rhythms. Appendix A includes a compilation of information about each piece within the Chantworks collection, with emphasis on each piece's compositional style, pedagogical merits, and other details worthy of analysis.