Transportation has unfavorably influence on a quality of enviroment. Increase of traffic leads to construction of new motorways and to intensify the traffic on current comunications. A consequence is more polluted hard surfaces, when surface-wash contaminate soil, surface water and underground water. Devices for treating contamined water, such as oil-separators, are very actual in these days. The subject of this thesis was to test the possibilities of increasing effectiveness of mechanical separator for light liquids by installing various types of constructions. Target was to determine effectiveness of this conventional technology, which is energetically and technically simple and find out applicability for first step cleaning and further usage.

This work was composed of two main parts. In a first step, a electrochemical cell was developed, which could allow the in-situ, in-operando analysis of the functioning battery. The processes taking place inside a running lithium-sulphur cell were then observed and identified with the help of Raman spectroscopy. In a second step, the performance of the cell was studied while using novel cathode materials, as well as modified commercial separators.

A multi-functional RuO₂ nanoparticle-embedded mesoporous carbon-coated separator is used as an electrocatalytic and adsorbing polysulphide-net to enhance the redox reaction of migrating polysulphides, to improve active material utilization and boost the electrochemical performance of lithium–sulphur batteries.

Ombord på Sjöfartshögskolans fartyg Calmare Nyckel, fanns en anläggning för rening av oljehaltigt vatten. Eftersom anläggningen började bli gammal och det var svårt att få tag i reservdelar, samt att nya innovativa lösningar uppkommit under senare år, önskade skolan byta ut den gamla anläggningen mot en ny från Marinfloc AB.   Författarna till denna rapport fick i uppdrag av skolan att ta fram installationsunderlag i form av ritningar, materialförteckningar samt instruktioner på hur arbetet bör genomföras. Även en analys skulle genomföras, där den gamla och den nya anläggningen jämfördes med avseende på renhet hos det separerade länsvattnet.    Syftet med projektet var att ersätta befintlig länsvattenseparator mot en ny modernare anläggning, få den besiktigad och godkänd av berörda myndigheter. Syftet med denna rapport är att redogöra för projektets genomförande, enligt projektdirektivet.   Resultatet av projektet var att Calmare Nyckel blev utrustad med en fullt fungerande, modern anläggning för rening av länsvatten. Den nya anläggningen renade länsvattnet mycket effektivt och bidrar därmed till mindre med föroreningar i världens hav. / On board the Maritime Academy vessel Calmare Nyckel, they had equipment for treatment of oily water. Since the equipment was beginning to get old, and that it was difficult to find spare parts, as well as new innovative solutions had arisen in recent years, the academy wanted to replace the old equipment with new from Marinfloc AB.   The authors of this report were assigned by the academy to provide the installation basis in form of drawings, material list and instructions on how the work should be carried out. Also an analysis would be carried out, where the old and the new equipment were to be compared with regard to the purity of the separated bilge water.   The purpose of the project was to replace the existing oily water separator with a new modern one, get it inspected and approved by authorities. The purpose of this report is to give account for the project implementation in accordance to the projects directive.   The result of the project was that Calmare Nyckel had been equipped with a full functioning, modern equipment for purification of bilge water. The new equipment purified bilge water very efficient, thereby contributing to less pollution in the world's oceans. / Installation Marinfloc

The typical preparation plant producing coal for the utility market targets a relative separation density in the plant of around 1.60 whereas plants generating metallurgical coal use relative cut point density values approaching 1.50. In some cases, achieving the specified coal quality requires operating at lower cut point values, which results in a significant loss of valuable coal. In these situations, a middlings stream can be produced using a secondary separator or a three-product unit, which would allow crushing of the middlings for liberation purposes and re-introduction into the plant feed. In this manner, higher quality coal can be produced while maximizing plant yield. A detailed laboratory analysis was conducted to study the liberation characteristics resulting from the crushing of middlings at different top sizes. The experimental data were later used as input for modeling and simulation of plant flowsheet in LIMN. Simulations were run for several regrinding cases. The results of the current study investigating the economic benefits of middlings liberation and re-treatment are presented and discussed in this thesis. Improvement up to 6% in plant yield with 16-21% reduction in ash and 14-18% sulfur reductions can be achieved by crushing the +1/2 inch middlings to a ½-inch top size.

There is a lack of fundamental studies by means of state of the art numerical and scale modeling techniques scrutinizing the theoretical and technical aspect of air table separators as well as means to comprehend and improve the efficiency of the process. The dissertation details the development of a workable empirical model, a numerical model and a scale model to demonstrate the use of a laboratory air table unit. The modern air-based density separator achieves effective density-based separation for particle sizes greater than 6 mm. Parametric studies with the laboratory scale unit using low rank coal have demonstrated the applicability with regards to finer size fractions of the range 6 mm to 1 mm. The statistically significant empirical models showed that all the four parameters, i.e, blower and table frequency, longitudinal and transverse angle were significant in determining the separation performance. Furthermore, the tests show that an increase in the transverse angle increased the flow rate of solids to the product end and the introduction of feed results in the dampening of airflow at the feed end. The higher table frequency and feed rate had a detrimental effect on the product yield due to low residence time of particle settlement. The research further evaluated fine particle upgrading using various modeling techniques. The numerical model was evaluated using K-Epsilon and RSM turbulence formulations and validated using experimental dataset. The results prove that the effect of fine coal vortices forming around the riffles act as a transport mechanism for higher density particle movement across the table deck resulting in 43% displacement of the midlings and 29% displacement of the heavies to the product side. The velocity and vector plots show high local variance of air speeds and pressure near the feed end and an increase in feed rate results in a drop in deshaling capability of the table. The table was further evaluated using modern scale-modeling concepts and the scaling laws indicated that the vibration velocity has an integral effect on the separation performance. The difference between the full-scale model and the scaled prototype was 3.83% thus validating the scaling laws.

This thesis includes two topics. One is a low-power high-speed 8-bit pipelining CLA design using dual threshold voltage (dual- Vth) domino logic. The other is a low-cost digital I/Q separator for DVB-T receivers. A high speed and low power 8-bit CLA using dual- Vth domino logic blocks arranged in a PLA-like style with pipelining is presented. According to parallely precharge and sequentially evaluate in a cascaded set of domino logic blocks, transistors in the precharge part and the evaluation part of dual- Vth domino logic are, respectively, replaced by high Vth transistors to reduce subthreshold leakage current through OFF transistors, and low Vth transistors. Moreover, an nMOS transistor is inserted in the precharge phase of the output inverter such that the two-phase dual- Vth domino logic can be properly applied in a pipeline structure. Consequently, the proposed design keeps the advantage of high speed while attaining the effect of low power dissipation. A low-cost digital I/Q separator is presented in the second part of this thesis. Using digital I/Q separator in place of the traditional analog I/Q separator guarantees the design conquer gain and phase mismatch problems between the I and Q channels. The proposed design can berealized by inverters and shifters such that the goal of low cost can be achieved.

This study was concerned with the most common reverse flow type of cyclones where the flow enters the cyclone through a tangential inlet and leaves via an axial outlet pipe at the top of the cyclone. Numerical computations of two different cyclones were based on the so-called Stairmand cyclone. The difference in geometry between these two cyclones was basically characterized by the geometrical swirl number Sg of 3.5 and 4. Turbulent secondary flows inside a straight square channel have been studied numerically by using Large Eddy Simulation (LES) in order to verify the implementation process. Prandtl’s secondary motion calculated by LES shows satisfying agreement with both, Direct Numerical Simulation (DNS) and experimental results. Numerical calculations were carried out at various axial positions and at the apex cone of a gas cyclone separator. Two different NS-solvers (a commercial one, and a research code), based on a pressure correction algorithm of the SIMPLE method have been applied to predict the flow behavior. The flow was assumed as unsteady, incompressible and isothermal. A k − epsilon turbulence model has been applied first using the commercial code to investigate the gas flow. Due to the nature of cyclone flows, which exhibit highly curved streamlines and anisotropic turbulence, advanced turbulence models such as RSM (Reynolds Stress Model) and LES (Large Eddy Simulation) have been used as well. The RSM simulation was performed using the commercial package CFX4.4, while for the LES calculations the research code MISTRAL/PartFlow-3D code developed in our multiphase research group has been applied utilizing the Smagorinsky model. It was found that the k − epsilon model cannot predict flow phenomena inside the cyclone properly due to the strong curvature of the streamlines. The RSM results are comparable with LES results in the area of the apex cone plane. However, the application of the LES reveals qualitative agreement with the experimental data, but requires higher computer capacity and longer running times than RSM. These calculations of the continuous phase flow were the basis for modeling the behavior of the solid particles in the cyclone separator. Particle trajectories, pressure drop and the cyclone separation efficiency have been studied in some detail. This thesis is organized into five chapters. After an introduction and overview, chapter 2 deals with continuous phase flow turbulence modeling including the governing equations. The emphasis will be based on LES modelling. Furthermore, the disperse phase motion is treated in chapter 3. In chapter 4, the validation process of LES implementation with channel flow is presented. Moreover, prediction profiles of the gas flow are presented and discussed. In addition, disperse phase flow results are presented and discussed such as particle trajectories; pressure drop and cyclone separation efficiency are also discussed. Chapter 5 summarizes and concludes the thesis.

Zugl.: Magdeburg, Universiẗat, Habil.-Schr., 2009.

Development of alternative cathodes that have high capacity and long cycle life at an affordable cost is critical for next generation rechargeable batteries to meet the ever-increasing requirements of global energy storage market. Lithium-sulfur batteries, employing sulfur cathodes, are increasingly being investigated due to their high theoretical capacity, low cost, and environmental friendliness. However, the practicality of lithium-sulfur technology is hindered by technical obstacles, such as short shelf and cycle life, arising from the shuttling of polysulfide intermediates between the cathode and the anode as well as the poor electronic conductivity of sulfur and the discharge product Li2S. This dissertation focuses on overcoming some of these problems. The sulfur cathode involves an electrochemical conversion reaction compared to the conventional insertion-reaction cathodes. Therefore, modifications in cell-component configurations/structures are needed to realize the full potential of lithium-sulfur cells. This dissertation explores various custom and functionalized cell components that can be adapted with pure sulfur cathodes, e.g., porous current collectors in Chapter 3, interlayers in Chapter 4, sandwiched electrodes in Chapter 5, and surface-coated separators in Chapter 6. Each chapter introduces the new concept and design, followed by necessary modifications and development. The porous current collectors embedded with pure sulfur cathodes are able to contain the active material in their porous space and ensure close contact between the insulating active material and the conductive matrix. Hence, a stable and reversible electrochemical-conversion reaction is facilitated. In addition, the use of highly porous substrates allows the resulting cell to accommodate high sulfur loading. The interlayers inserted between the pure sulfur cathode and the separator effectively intercept the diffusing polysulfides, suppress polysulfide migration, localize the active material within the cathode region, and boost cell cycle stability. The combination of porous current collectors and interlayers offers sandwiched electrode structure for the lithium/dissolved polysulfide cells. By way of integrating the advantages from the porous current collector and the interlayer, the sandwiched electrodes stabilize the dissolved polysulfide catholyte within the cathode region, resulting in a high discharge capacity, long-term cycle stability, and high sulfur loading. The novel surface-coated separators have a polysulfide trap or filter coated onto one side of a commercial polymeric separator. The functional coatings possess physical and/or chemical polysulfide-trapping capabilities to intercept, absorb, and trap the dissolved polysulfides during cell discharge. The functional coatings also have high electrical conductivity and porous channels to facilitate electron, lithium-ion, and electrolyte mobility for reactivating the trapped active material. As a result, effective reutilization of the trapped active material leads to improved long-term cycle stability. The investigation of the key electrochemical and engineering parameters of these novel cell components has allowed us to make progress on (i) understanding the materials chemistry of the applied functionalized cell components and (ii) the electrochemical performance of the resulting lithium-sulfur batteries. / text