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This thesis details the results of an integrated study of carbonate platform sedimentology, geometry, evolution and diagenesis within a sequence stratigraphic framework. This study has been based on the Upper Cretaceous carbonates within the Tremp basin of the Spanish Pyrenees, which, through the effects of minor tectonic deformation during the later parts of the Pyrenean orogeny, are exceptionally well exposed and can be studied in the form of a platform to basin cross-section upon a scale that is comparable to that of a seismic section. This study concentrates on the mid-Turonian to Coniacian-aged Congest platform and its associated basinal succession, whose sedimentology and geometrical features, in particular cyclic progradational cycles, and evidence of repeated flooding and exposure of the platform-top are interpreted in terms of . fluctuations in relative sea-level and associated variations in available accommodation space. These interpretations, together with evidence of subaerial exposure in the form of karst features, intensive dissolution and the presence of speleo-cements, are used to propose a dynamic 'forced regression' model for the evolution of the Congost platform, which involves two phases of platform development, separated by a period of forced regression. The primary and secondary porosity afforded by the abundant bi-mineralic rudists within the platform-top sediments allows for a detailed and comprehensive diagenetic study of these carbonates, in the form of a case study for a number of interesting diagenetic features. In addition to standard petrography, cathodoluminescence and stable isotope studies have been employed and have allowed the identification of such features as botryoidal calcitic marine cements, neomorphism which occurred in lagoonal waters and speleo-cements. This study also provides a detailed investigation of the diagenesis associated with subaerial exposure and the development of sequence boundaries. Differences in the early diagenesis of these carbonates from different parts of the Congost platform suggest that two separate phases of platform development experienced: 1) differing pore-fluid regimes; 2) differing frequencies and duration of subaerial exposure events; and 3) different magnitudes of relative sea-level fall. These features are considered in terms of variations in accommodation space during platform development and are used to develop the dynamic 'forced regression' model for the evolution of the Congost platform. A succession of Cenomanian to Santonian-aged basinal and slope sediments which can be correlated with the contemporaneous Santa Fe, Congost and Sant Comeli platforms and contain a large amount of allochthonous debris, much of which is derived from underiying units, are described and interpreted in terms of local tectonic activity and relative sea-level change. The final part of this thesis presents a new sequence stratigraphic model for the mid-Turonian to Coniacian-aged Congost platform which is compatible with the observations and conclusions of this study. This new sequence stratigraphic model suggests that the Congost platform developed within two separate depositional sequences, albeit with one being on a much larger scale than the other. Sequence boundaries are characterised by subaerial exposure on the platform top which can be correlated with hardgrounds and/or glauconite accumulations within the more basinal locations, overlain by deeper-water facies. The presence of submarine onlap surfaces and down-slope slide deposits immediately above the sequence boundaries suggests that the major transgressive events which followed sequence boundary development were brought about by local extensional tectonic activity, while the stratigraphic cyclicity within the sequences and major falls in sea-level which produced the sequence boundaries are interpreted to have resulted largely from eustatic processes.

次級房貸風暴造成全球金融海嘯，投資人對金融衍生性商品一度避之唯恐不及。在各方韃伐之下，卻忽略衍生性商品作為風險管理的工具及促進市場效率及完整性的重要性，未來在金融市場著重風險控管的趨勢下，衍生性商品仍會扮演不可或缺的角色。 本論文針對市場上交易量較大的利率衍生性金融商品及匯率衍生性金融商品，進行個案的評價與分析，提供投資人或發行者一個明確易懂的評價分析方式，能使市場上衍生性商品的交易更具效率性。 本論文以瑞士銀行所發行的「上下限固定期限交換利率利差連動債券」及「數據百慕達式匯率連動債券」為例，分別以LIBOR Market Model和最小平方蒙地卡羅法做為評價方式。依據評價結果分析發行商的避險策略與投資人所面對的投資風險。

This report studies the generation of new solutions to Einstein's field equations in general relativity by the method of sigma models. If, when projected from four to three dimensions, the relativistic action decouples into a gravity term and a non-linear sigma model term, target space isometries of the sigma model can be found that correspond to generating new solutions. We give a self-contained description of the method and relate it to the early articles through which the method was introduced. We discuss the virtues of the method and how it is used today. We find that it is a powerful technique of finding new solutions and can also give insight to the general features of the theory. We also identify some possible further developments of the method.

This research is aimed at developing the method for efficiently using the water in irrigation schemes in semi-arid regions. These irrigation schemes are often short of water to irrigate entire culturable command area (CCA) with maximum water requirement of different crops and are characterised with different weather patterns, soils and the possibility to grow several crops. The CCA of these schemes is also large with several users or units, each having different characteristics. The previous research in this field was mostly either on optimum allocation of the resources considering the irrigation scheme as a whole or on evaluating the performance of the irrigation scheme for certain irrigation schedules for different units in the scheme. However in such schemes optimum allocation of resources (land and water) to different crops and their distribution over different units is important (optimum allocation plan, OAP). In the present study, the method and a computer model are developed to prepare OAPs for these irrigation schemes under rotational water supply, by incorporating the concepts of deficit irrigation and productivity and equity in the optimisation process. The previous research stressed the importance of equity observed in different ways but seldom adopted in optimum allocation of resources. Therefore this method includes the preparation of OAPs while observing equity in allocation of land and water resources and distribution of crop production and net benefits. The developed model, Area and Water Allocation Model (A WAM), consists of four phases each one for generating irrigation strategies, preparing irrigation programme for each irrigation strategy, screening irrigation programmes and allocating resources optimally to different crops in different units. The A W AM estimates the irrigation water requirement, crop yield and net benefits by simulating the various process in the irrigation scheme, produces the OAPs at preseason planning with different scenarios of productivity and equity and management options, develops the steady OAP by considering the temporal variability in the weather and modifies the allocation plan optimally during the intraseasonal operation of the irrigation scheme. A W AM operates in seven different modes to achieve this. These are simulation, calibration, generation, optimisation, planning, operation and evaluation. The A W AM was applied to Nazare Medium Irrigation Project (medium lmgation scheme) in semi-arid region of Maharashtra State, India to evaluate the existing practice of irrigation (fixed depth irrigation), full depth irrigation and deficit irrigation for obtaining the OAPs. The practice of deficit irrigation was found to be beneficial over the existing approach and full depth irrigation. The OAPs at preseason planning are obtained for several alternatives and compared. The OAPs were obtained for different equity criteria. The productivity and equity were found to be inversely related. The method is proposed to obtain the stable OAP with A WAM by considering several years' data. The present research contributes towards efficient utilisation of water in the irrigation scheme by incorporating the deficit irrigation and productivity and equity in obtaining OAPs, developing the methods to obtain the steady OAP and modifying the allocation plan optimally during the intraseasonal operation of the irrigation scheme.

Existing knowledge of the flow in a river past a groyne is inadequate to explain fully the siltation and scour that take place around such a structure. A survey of published material reveals controversy over the choice of pertinent flow parameters affecting the maximum scour depth.

No description available.

No description available.

A new, two-dimensional model is presented for predicting the behaviour of tall, thin piezoelectric transducer structures, typical of those encountered in many ultrasonic phased array assemblies. Based on linear systems theory, the model may be represented in block diagram format, utilising feedback and feedforward loops to model mechanical and piezoelectric cross coupling, in addition to secondary and tertiary piezoelectric generation. As a result, the model permits a ready understanding of the electrical, mechanical and piezoelectric interactions which take place when two principal vibrational modes are present within a transducer structure. Comprehensive experimental and theoretical results are shown to produce close agreement, and compare favourably with alternative modelling strategies. It is considered that this novel approach will be of considerable benefit to the analysis and understanding of the transduction process within such structures.