Blowout preventers are designed to shut in a well under pressure so that formation fluids that have moved into the wellbore can be contained and circulated out while continuous control of the well is maintained. Control Systems for the BOPs are of necessity highly efficient hydraulic systems. The objective is to operate functions, such as closing rams, on the BOP stack in as short a time as possible. Supplying enough volume of pressured hydraulic fluid to operate those emergency functions is essential. To have the necessary quantity of control fluid under pressure requires storing this fluid in accumulators. These accumulators operate by the expansion and compression of nitrogen gas that is separated from hydraulic fluid by either rubber bladders or pistons. Accumulators are used both on the surface and at the seafloor. As long as you use accumulators on the surface or in relatively shallow waters, you may not have a problem with the volume of hydraulic fluid capacity of gas charged accumulators. The problem may arise when the wellhead is at water depth of more than 3500 ft. In deep water drilling, the accumulators should be placed on the subsea blowout preventer stack to reduce hydraulic response times and provide a hydraulic power supply in case of interruption of surface communication. Accumulators are also used in subsea production control systems to provide local storage that allows smaller line sizes in control umbilicals. Hydraulic fluid capacity of an accumulator drops to 15% of its capacity on the surface and even less, depending on the water depth. A large number of accumulators are needed to perform BOP functions that could have been done by just a few of them on the surface or at relatively shallow water depth. Gas inside gas charged accumulators does not behave like an ideal gas as we go to very deep water, due to high hydrostatic pressure at that water depth. The higher the ambient pressure, the more the gas behaves like a real gas rather than an ideal gas and the lower the fluid capacity of the accumulators. Compressed gas has energy in it, and can release this energy at the time desired, that’s why it is used in accumulators. Now, we have to look for something that is able to store energy, but unlike the nitrogen, its functionality must not be affected by the increasing hydrostatic pressure of water as a function of water depth. Springs and heavy weights will be discussed as two options to replace nitrogen in accumulators. Efficient deep water accumulators would reduce the number of accumulators required in deepwater and cut the cost of the project. With the advent of such efficient accumulators, we can hope that one of the numerous problems of deepwater drilling has been solved and we can think of drilling in even deeper waters.

In this thesis, the design of a high intensity accumulator ring for the European Spallation Source Neutrino Super Beam (ESSnuSB) is considered. The European Spallation Source (ESS) linear accelerator (Linac), presently being constructed in Lund, Sweden, presents an interesting opportunity to also host an experiment to detect neutrino CP violation. 0.7 ms long H- pulses would be accelerated to 2 GeV and collide with a target, producing pions which then decay into neutrinos. To focus the pions a toroidal magnet (''neutrino horn'') is pulsed with a 350 kA current. The peak current is about 5 μs long, which requires the H- pulses to be shortened to about the same length using an accumulator ring that is located between the linac and the target. The H- would be stripped of their electrons using either a thin carbon foil or a laser beam during injection into the ring. Foil stripping is limited by the lifetime of the foil, which depends on the temperature to which it is heated by the beam. The temperature is simulated in a computer model and the results indicate that it does not rise above the critical temperature (2500 K). The high number of protons (1015) circulating in the ring could cause instabilities due to the collective charge of the particles, known as the space charge effect. The space charge tune shift is calculated for the ESSnuSB and different solutions are discussed. The result of a design accumulator lattice for the ESSnuSB, based on the Spallation Neutron Source, at Oak Ridge National Laboratory, Tennessee, U.S., and made using the computer program Methodical Accelerator Design (MAD), is presented.

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Freudenberg Sealing Technologies has developed a new concept for the manufacture of diaphragm accumulators. Its advantages are a reduced need for components, fewer process steps, shorter assembly times, a higher level of product cleanliness, and an expansion of the product portfolio into additional fields of application. These diaphragm accumulators also weigh significantly less. This is opening up new opportunities for applications in the automotive and industrial fields. The assembly concept is based on a hermetically sealed pressure chamber in which the joining of the two housing halves with the help electromagnetic pulse technology (EMPT) as well as the filling of the gas side with nitrogen takes place in a single operation. In this way, downstream filling to generate the initial gas charge is no longer necessary.

The number of batteries, namely accumulators, is growing. Consequently, their take-away and a need of recyclation is increasing too. It is thus necessary to find a suitable way to their optimalization that can lead to the establishment of new waste collection machineries. This study deals with the data analysis by ECOBAT s.r.o. company, data processing and a model construction (in five different versions). The output of the diploma thesis is a model of the batteries collection enabling closer look on take-away routes, The model is based on the distances of take-away routes based on a principle of the utility areas and a role of a transport. The data are obtained from ArcGIS 10.5 and subsequently handled in Microsoft Excel. The outputs are the map schemes issuing from five different versions. The first one is showing the current situation, The other one is showing the version of treating units in three largest towns of the Czechia, the third one treating units in all the towns with above 100 000 inhabitants. The forth on eis showing a possibility to have a collection point in each of the county seats. The last one has the same location, but the threating units have higher capacities. The model is general, there is therefore a possibility of using it for other similar situations.

All practical text search systems use inverted indexes to quickly resolve user queries. Offline index construction algorithms, where queries are not accepted during construction, have been the subject of much prior research. As a result, current techniques can invert virtually unlimited amounts of text in limited main memory, making efficient use of both time and disk space. However, these algorithms assume that the collection does not change during the use of the index. This thesis examines the task of index maintenance, the problem of adapting an inverted index to reflect changes in the collection it describes. Existing approaches to index maintenance are discussed, including proposed optimisations. We present analysis and empirical evidence suggesting that existing maintenance algorithms either scale poorly to large collections, or significantly degrade query resolution speed. In addition, we propose a new strategy for index maintenance that trades a strictly controlled amount of querying efficiency for greatly increased maintenance speed and scalability. Analysis and empirical results are presented that show that this new algorithm is a useful trade-off between indexing and querying efficiency. In scenarios described in Chapter 7, the use of the new maintenance algorithm reduces the time required to construct an index to under one sixth of the time taken by algorithms that maintain contiguous inverted lists. In addition to work on index maintenance, we present a new technique for accumulator pruning during ranked query evaluation, as well as providing evidence that existing approaches are unsatisfactory for collections of large size. Accumulator pruning is a key problem in both querying efficiency and overall text search system efficiency. Existing approaches either fail to bound the memory footprint required for query evaluation, or suffer loss of retrieval accuracy. In contrast, the new pruning algorithm can be used to limit the memory footprint of ranked query evaluation, and in our experiments gives retrieval accuracy not worse than previous alternatives. The results presented in this thesis are validated with robust experiments, which utilise collections of significant size, containing real data, and tested using appropriate numbers of real queries. The techniques presented in this thesis allow information retrieval applications to efficiently index and search changing collections, a task that has been historically problematic.

This Master Thesis has been performed at Atlas Copco Rock Drills AB, Örebro and at Linköping University, Sweden from February 2010 through August 2010.The project deals with performance improvement of hydraulic rock drill machine manufactured by Atlas Copco Rock Drills. Atlas Copco Rock Drills AB is a world leading supplier of percussive rock drilling equipment for surface and underground applications. HOPSAN, a software developed at Linkoping University, provides an integrated simulation environment for simulation of fluid power systems. During the work, a HOPSAN model of a piston accumulator has been developed and its performance with a rock drill has been studied. Furthermore, the fatigue strength calculations of a piston accumulator has been made on the basis of stress analysis performed using the ANSYS software. One of the rock drills of valveless type, developed at Atlas Copco Rocktec Division works at higher efficiency than the conventionally used rock drills. But the problem with this type of drill is that the piston swings between two large and highly pressurized oil volume which causes strength problems in the housing of the rock drill. The aim of this work is to achieve the higher efficiency of the rock drill without having any strength problems. Therefore, some study and research is proposed to replace the large oil volume by one or two piston accumulators. This thesis work involves modelling, simulation, design and fatigue strength calculations of a piston accumulator and its implementation to the rock drill. Optimization of the piston accumulator has also been conducted while working with the rock drill so that highest possible eciency could be achieved. The performance of the rockdrill with piston accumulator has been analyzed and results are studied. In the end, a short fatigue life calculations are performed and results are discussed. Prior to fatigue life calculations, a transient dynamic stress analysis has been performed and stress amplitudes are identified which contributes to the accumulated damage to piston in accumulator.

In this thesis, we develop an automatic hardware synthesizer for multiplier-based arithmetic functions such as parallel multipliers/multiplier-accumulator/inner-product calculator. The synthesizer is divided into two major phases. In the first phase called pre-layout netlist generation, the synthesizer generates the gate-level verilog codes and the corresponding test fixture file for pre-layout simulation. The second phase, called layout-generation, is to produce the CIF file of final physical layout based on the gate-level netlist generated in the first phase. The thesis focuses on the first phase. The irregular connection of the Wallace tree in the parallel multiplier is optimized in order to reduce the overall delay and power. In addition to the conventional 3:2 couter that is usually included in standard cell library, our synthesizer can select other different compression elements that are full-custom designed using pass-transistor logic. We also propose several methods to partition the final addition part of the parallel multiplier into several regions in order to further reduce the critical path delay and the area cost. Thus, our multiplier generator combines the advantages of three basic design approaches: high-level synthesis, cell-based design and full-custom design along with area and power optimization.

The number of batteries and especially accumulators, which we use, is growing every time and collection with take-away is growing too. Now it is absolutelly important look for a way to optimalization, which can be for example builing new processing equipment. Graduation thesis deal with data analysis from battery collection, data processing and building a data model in four variants. Graduation thesis work with number of battery and accumulators in czech households and bring answer to question "How many batteries we have got approximately in our households?" Output is processing questionary about Research of battery in households,which is used in next work. The main output is data model.Model work with distance of take-way route on principe Service area and Transportation theory. Data are obtained by ArcGIS and processed in Excel. The output are map schematics which are based from four studies. First study shows present state, next shows battery factory in another capital town in regions of the Czech Republic. Third shows variant battery factories in three biggest cities and fourth battery factory in all czech cities, that have 100 000 residents. The best combinations is probably study with three biggest cities, because in this study is saving 50 % of costs and withal it is not necessary build many...