There exist various applications of transportation of slurries through pipelines all over the world. In the present study, the problem is formulated as a &quot / transportation problem&quot / to determine the pipe diameters and amounts of slurry to be transported from the demand (production) points to the processing (factory) points. The minimization of the cost consisting of the pipe and energy cost terms is considered as the objective function to determine the stated decision variables. Pipe cost is given as the function of pipe diameters and the energy cost is defined as function of pipe diameters and slurry amounts. Energy cost is obtained by using the relation that is previously determined after the experimental studies made for the magnetite ore. The optimization method used in the study is genetic algorithm method. A commercially available software written in C language is used and modified for the present study The proposed methodology to solve this nonlinear programming problem is applied to a transportation system and it is seen that the methodology made the complex, labor intensive equation solution process very convenient for the users.

Since the discovery of cuprate superconductors, PrBa2Cu3O7 (Pr123) has attracted much attention due to its nonsuperconductivity and other anomalies. The very recent reports on superconducting Pr123 instead of putting an end of this issue, virtually stimulate more controversies. One of the proposed explanations for the recently observed superconductivity in Pr123 is that the samples could be Ba-rich Pr123 to investigate this possibility, we prepared Pr1-xBa2+xCu3O7 (x=1~0.3) and Pr1-xCaxBa2Cu3O7 (x=0~0.6) as comparison. X-ray absorption near edge spectroscopy (XANES) indicates an increase in carrier concentration with Ba and Ca doping, which is consistent with resistivity and thermoelectric power(TEP) data. However, carriers are introduced in a peculiar why rather than simply add into CuO2 plane.

Los objetivos básicos de este trabajo son: 1. Valorar la sensibilidad, especificidad, valor global, valor predictivo positivo y valor predictivo negativo de la tomogammagrafía de perfusión gatillada con 99mTc MIBI para el diagnóstico de la enfermedad coronaria en los pacientes sin infarto previo. 2. Aplicar el teorema de Bayes con la finalidad de determinar para qué valores de prevalencia de la enfermedad coronaria resulta más apropiada la indicación de la tomogammagrafía de perfusión con 99mTc MIBI. 3. Comprobar cuáles son los niveles mínimos de consumo miocárdico de oxigeno (frecuencia cardíaca, presión arterial sistólica y producto frecuencia cardiaca por presión arterial sistólica) y de consumo máximo de oxigeno (Mets) para conseguir un rendimiento óptimo de la tomogammagrafía de perfusión con 99mTc MIBI. 4. Estudiar el incremento que representa para la precisión diagnóstica de la tomogammagrafía de perfusión con 99mTc MIBI el asociar la administración de dipiridamol endovenoso durante la realización de la prueba de esfuerzo convencional en aquellos pacientes en los que la ergometría es insuficiente. 5. Valorar el rendimiento diagnóstico de la adicion de atropina a dipiridamol en pacientes con imposibilidad para realizar esfuerzos físicos. 6. Determinar el papel de la tomogammagrafía de perfusión con 99mTc MIBI en el diagnóstico de la enfermedad coronaria multivaso. 7. Comprobar el grado de coincidencia entre la tomogammagrafía de perfusión 99mTc MIBI y la coronariografía en el diagnóstico de la lesión culpable. 8. Cuantificar el miocardio en riesgo mediante la tomogammagrafía de perfusión con 99mTc MIBI y correlacionarlo con la cuantificación coronariográfica. 9. Valorar la fracción de eyección, volúmenes ventriculares de fin de sístole y de diástole y el engrosamiento sistólico con mapa polar inmediatamente posterior al apremio físico o farmacológico y en reposo para cuantificar la progresión fisiologica de la función ventricular o el deterioro de la contractilidad secundaria a la presencia de isquemia y/o atontamiento miocárdico.

A descriptive sediment movement model has been created for an area of the nearshore zone near Gibraltar Point, Lincolnshire on the basis of evidence from studies of sediments, sandbank and channel morphology, bedforms, tidal currents and sediment tracer experiments. The area is subject to linear tidal currents which have created a system of tidal current ridges, tidal channels and an ebb-tidal delta. Sediment movement associated with these sandbanks and channels was found to have a net northerly drift related to an ebb tidal residual in the Boston Deep, the largest channel in the area. Sediment circulation around the sandbank system was considered to be essentially closed with a large sediment storage element represented by the sandbanks. An area of the foreshore was identified as a possible location for movement of sediment from the nearshore zone to the foreshore zone. Six Woodhead seabed drifter experiments were conducted to assess the validity of the sediment movement model. The net northerly drift of the sediment within the sandbank system was confirmed and was found to extend as far north as Ingoldmells Point. Movement of sediment from the nearshore zone to the foreshore zone was confirmed at the location suggested in the sediment movement model and was also predicted at Ingoldmells Point. The time of stranding of seabed drifters was found to coincide with periods of winds blowing offshore and from the north-east and with, periods of increasing tidal current velocity as the lunar tidal cycle approaches spring tide conditions. Movement of sediment from the nearshore zone to the foreshore zone may also occur under these environmental conditions. A study of the historical development of the sandbanks suggested an overall decrease in the size of tidal current ridges since 1871 which may be related to a decrease in the amount of sediment available for the maintenance of the sandbanks. A ness south of the Skegness Middle sandbank was interpreted as a morphological expression of foreshore adjustment to the migration of sediment from the nearshore zone to the foreshore zone at this location.

Numerical dam break analyses of Kirazlik&ouml / pr&uuml / Dam are performed under various hydraulic scenarios. Kirazlik&ouml / pr&uuml / Dam is located on the G&ouml / kirmak River near the city of Bartin. The objective of these analyses is to investigate adverse effects of such dam break failure on the regions downstream of the dam. The numerical model used in the simulations is FLDWAV, which is developed by the National Weather Service (NWS) in the United States. It appears that most adversely effected regions are those that are closest to the dam location. The results of these simulations can be used sufficiently to prepare emergency action plans in case of possible failures.

Marine anthropogenic noise is increasing, along with concern about its impact on the environment. Hence minimising noise within engineering design is important, including in applications such as ships, submarines and turbines. The desire to mitigate noise may also be related to reducing the detectability of certain types of marine craft. Noise reduction typically focuses on rotating machinery such as propellers, due to the high velocity of the blades. A common source of broadband noise in engineering scenarios is often termed inflow turbulence noise. Resulting from upstream turbulence impinging onto rotor blades, this source typically dominates the low to mid range of the frequency spectrum. This is due to the high turbulence intensity and large length scales present in the inflow turbulence, which exceed those generating competing noise sources. This thesis uses a library of numerical tools to simulate broadband inflow turbulence noise. Synthetic turbulence is generated numerically within the simulations. Turbulence is resolved on the grid by solving the filtered Navier-Stokes equations. Based on the assumption of incompressible flow, noise sources may be predicted without resolving acoustic waves on the grid. This decoupling of hydrodynamic and acoustic processes means that radiated noise may be estimated using an acoustic analogy. Validation of two inflow turbulence generators revealed the importance of obtaining the prescribed turbulence statistics, as well as minimising artificial pressure fluctuations. This is used to simulate homogeneous isotropic turbulence impinging onto a foil, allowing acoustic sources to be located. The far-field sound prediction is in good agreement with experimental measurement data for low frequencies. It is then shown that the effect of foil thickness on noise can successfully be predicted using the proposed methodology. Noise radiation from a tidal turbine is then estimated by fully resolving all turbine blades, both spatially and temporally, in the simulation. A good agreement is seen in comparison to an analytical model, demonstrating that the simulation captures the dominant flow features which affect the acoustic spectrum. These spectral ‘humps’ are a result of turbulence-rotor interaction, which is implicitly included. Full scale noise estimates made from the simulations are then used to inform environmental impact assessment; the turbine hydrodynamic noise is not expected to be an issue in this regard.

In 2012 106 vessels over 100 gross tonnes were lost. During the damage incidents many of these vessels required assistance from shore based emergency response services with regards to their damaged strength to stabilise the situation, preserve life, prevent environmental disaster and limit financial costs to owners and insurers. The research work presented in this Engineering Doctorate Thesis surrounds the strength assessment of damaged steel ship structures, the influence of damage on the strength of steel-plated structures and methods for assessing the residual strength of a vessel in an emergency. The focus of the work is to improve the modelling of damaged steel ship structures within an emergency situation, in order to improve guidance provided to a stricken vessel during a damage incident or salvage process. Literature study has shown that structural idealisation through the use of interframe progressive collapse analysis, to be the current state of the art method for the rapid assessment of intact and damaged ship structures. However, a number of weaknesses have been identified in the method when applied to damage assessment. The literature study has also shown a lack of understanding of the effect of damage on steel-plated structures as specific analysis has not been performed previously. Significant research has been undertaken into the influence of damage, in the form of a hole, on the ultimate collapse strength of steel-plated structures. Three levels of structural modelling have been used, stiffened-plate, stiffened panel and grillage. Comparison of the predicted ultimate collapse strength by finite element analysis (FEA) with predictions using the interframe progressive collapse idealisation, has shown the calculated results to be conservative for the assessment of damaged structure when the failure mode remains in the interframe collapse form. However, changes in the failure mode lead to the interframe progressive collapse method over predicting the ultimate collapse strength. The analysis shows that even small damage events can lead to significant changes to the failure mode and resulting ultimate collapse strength of the structure. Such influences must be accounted for in any simplified method. A new method for the assessment of damaged ship structures is proposed that is capable of modelling a damage scenario more accurately. Demonstration of the method has shown the results to be less conservative than the current state of the art, when compared to FEA, for local analysis of damaged steel-plated structure. The ability of the method to account for the influence of damage, and the resulting failure modes, that may significantly influence the ultimate bending strength of the structure has also been demonstrated. The method implements a compartment level progressive collapse analysis with structural data captured through the use of the response surface method ‘kriging’, using data points provided from FEA. This method allows the critical damage variables to be captured and strength data accessible quickly for use in the analysis. The time to provide a solution to the damage scenario is equivalent to the existing interframe progressive collapse method. Therefore, the method is suitable for application within an emergency response or salvage service.

The acoustic remote sensing of subsea gas leakage, applied to the monitoring of underwater gas discharges from anthropogenic and natural sources, is becoming increasingly important. First, as the oil and gas industry is facing increasing regulation, there is a need to put more control in the industrial process and to assess the impact on the marine environment. The applications are diverse, including: early warnings of "blow-out" from offshore installations, detection of leaks from underwater gas pipelines, gas leakage detection from Carbon and Capture and Storage facilities (a process aimed at mitigating the release of large quantities of CO2 in the atmosphere), and seabed monitoring. Second, this technology has a role to play in oceanography for a better understanding of natural occurrences of gas release from the sea floor such as methane seeps. This is of major importance for the assessment of the exchange of gas between the ocean and the atmosphere with application to global warming. All those phenomena involve the formation and release of bubbles of different sizes. These are strong sources and scatterers of sound. Within this context, this thesis draws on a two part study. The first part experimentally addresses the accuracy of a passive acoustic inversion method for the quantification of gas release. Such a technique offers the advantage of lower power requirements for long term monitoring. It is common practice for researchers to identify single bubble injection events from time histories or time frequency representations of hydrophone data, and infer bubble sizes from the centre frequency of the emission. This is well suited for gas release at a low flow rate, involving solitary bubble release. However, for larger events, with overlapping of bubble acoustic emissions, the inability to discriminate each individual bubble injection events makes this approach inappropriate. Using an inverse method based on the spectrum of the acoustic emissions allows quantification of such releases with good accuracy. The inverse scheme is tested using data collected in a large test tank and data collected at sea during the QICS (Quantifying Impacts of Carbon Storage) project. The second part of the thesis addresses the problem of quantifying gas releases using active acoustics. Single beam echosounders are commonly used instruments in fisheries acoustics. When investigating gas release from the seafloor, they are frequently employed to study the spatial distribution of the gas releases. However, few studies make use of these data to quantify the amount of gas being released. Here, using the common multi-frequency ability of these systems, an inverse method aimed at determining gas volumes is developed. This is tested against simulated data and the method shows good performances in scenarios with limited data sets (data collected at limited number of frequencies). Then, using data collected at sea from methane seeps to the west of Svalbard (from two research cruises), the method is applied and compared to independent measurements of gas fluxes.

No description available.

A Finite Element Method (FEM) is developed to calculate rotationally symmetric acoustic propagation over short range intervals (0-5 km) in shallow oceans (0-200 m deep) at low frequencies (0-50 Hz). The method allows full two-way wave propagation in range dependent environments and includes coupling to a full elastic seabed. Numerical results from a computer program are presented for propagation upslope, downslope, over seamounts and across trenches in the seabed. The seabed is modelled as a pressure release surface, a fluid halfspace and an elastic, solid halfspace and the implications of each type of model are discussed. The halfspaces, being represented by a new set of infinite elements, are modelled without truncation. The results are presented primarily as plots of transmission loss against range for a fixed depth receiver. Subsidiary results show the effect of depth averaging the receiver location, and extract mode amplitude data to reveal the strength of mode coupling and backscatter in different environments.