Som en konsekvens av globaliseringen leder förändrade konkurrensvillkor till allt högre krav på dagens organisationer och kompetensen på dess medarbetare. Dessa förändringar har bland annat lett till att färre människor idag vill bli chefer och privat och offentlig sektor hotas av att lida brist på chefskandidater då allt färre människor säger sig vilja göra de uppoffringar som chefskapet innebär. Män har under årtionden dominerat inom de flesta positioner i arbetslivet. Trots att en lika stor andel kvinnor som män idag arbetar, lever dessa traditioner och könsstrukturer till viss mån kvar i moderna företag. Den största delen av alla nyutexaminerade akademiker är idag kvinnor. Många av dessa är till högre grad än män intresserade av att göra karriär. Trots att företagen väntas lida brist på framtida chefskandidater och trots att de flesta som ändå är villiga och utbildade nog till att bli chefer, är kvinnor, tycks det fortfarande vara något som hindrar företagen att rekrytera dessa till toppchefspositionerna. Denna studie belyser de interna faktorer som hindrar svenska företag att rekrytera fler kvinnliga toppchefer. Syftet med studien är att analysera och utvärdera rekryteringsprocessen hos sex olika företag, verksamma i privat sektor, för att på så sätt finna dessa faktorer. Empirin som insamlats har analyserats mot för undersökningen, relevanta teorier angående organisationens styrning och lärande samt teorier härrörande könsstrukturer. Undersökningen har baserats på en kvalitativ metod som tagit sig form genom sex djupintervjuer med personer ansvariga för rekryteringsprocessen på respektive företag. Resultatet av undersökningen bekräftar delvis vår syntes angående hur organisationens styrning och lärande samspelar med de könsstrukturer som ryms inom denna och hur dessa tillsammans påverkar rekryteringsprocessens utformning. Dock framgår det av undersökningen att den viktigaste och för övriga faktorer avgörande faktorn är organisationens styrning och på vilket sätt ledningen utformar denna. Detta då de företag som lyckats öka sin kvinnliga representation har använt sig av samma typ av styrning, dvs. av en styrning vars utmärkande drag karaktäriseras av en målformulering i dialog med de anställda och en kontinuerlig utvärdering av genomförandet.

A new centrifugal pump has been devised to handle two-phase flow. However, it requires full scale testing to allow further development. Testing is required to verify performance and to gain information needed to apply this design in the field. Further, testing will allow mathematical models to be validated which will allow increased understanding of the pump's behavior. To perform this testing, a new facility was designed and constructed. This facility consists of a closed flow loop. The pump is supplied by separate air and water inlet flows that mix just before entering the pump. These flows can be controlled to give a desired gas volume fraction and overall flow rate. The pump outlet flows into a tank which separates the fluids allowing them to re-circulate. Operating inlet pressures of up to three hundred PSIG will be used with a flow rate of twelve hundred gallons per minute. A two-hundred fifty horsepower electric motor is used to power the pump. The loop is equipped with instrumentation to measure temperature, pressure, flow rate, pump speed, pump shaft horsepower, shaft torque, and shaft axial load. The pump itself has a clear inlet section and a clear section allowing visualization of the second stage volute interior as well as numerous pressure taps along the second stage volute. This instrumentation is sufficient to completely characterize the pump. Design and construction details are provided as well as a history of the initial operating experiences and data collected. A discussion of lessons learned is given in the conclusions. Future projects intended to use this facility are also given. Finally, detailed design drawings are supplied as well as operating instructions and checklists.

Multiphase flow is associated with concurrent flow of more than one phase (gas-liquid, liquid-solid, or gas-liquid-solid) in a conduit. The simultaneous flow of these phases in a flow line, may initiate a slug flow in the pipeline. Hydrodynamic slug flow is an alternate or irregular flow with surges of liquid slug and gas pocket. This occurs when the velocity difference between the gas flow rate and liquid flow rate is high enough resulting in an unstable hydrodynamic behaviour usually caused by the Kelvin-Helmholtz instability. Active feedback control technology, though found effective for the control of severe slugs, has not been studied for hydrodynamic slug mitigation in the literature. This work extends active feedback control application for mitigating hydrodynamic slug problem to enhance oil production and recovery. Active feedback Proportional-Integral (PI) control strategy based on measurement of pressure at the riser base as controlled variable with topside choking as manipulated variable was investigated through Olga simulation in this project. A control system that uses the topside choke valve to keep the pressure at the riser base at or below the average pressure in the riser slug cycle has been implemented. This has been found to prevent liquid accumulation or blockage of the flow line. OLGA (olga is a commercial software widely tested and used in oil and gas industries) has been used to assess the capability of active feedback control strategy for hydrodynamic slug control and has been found to give useful results and most interestingly the increase in oil production and recovery. The riser slugging was suppressed and the choke valve opening was improved from 5% to 12.65% using riser base pressure as controlled variable and topside choke valve as the manipulated variable for the manual choking when compared to the automatic choking in a stabilised operation, representing an improvement of 7.65% in the valve opening. Secondly, implementing active control at open-loop condition reduced the riser base pressure from 15.3881bara to 13.4016bara.

In this thesis, an automatic control performance monitoring tool is analyzed and evaluated. The tool is called Control Loop Asset Monitor (CLAM) and is a part of the Asset Optimization extension to the ABB platform System 800xA. CLAM calculates and combines a number of performance indices into diagnoses. The functionality, choice of configuration parameters and the quality of the result from CLAM have been analyzed using data from the pulp mill Södra Cell Mörrum. In order to get reliable diagnoses from CLAM, it is important that it is correctly configured. It was found that some of the default parameters should be modified and the recommendations in the user guidelines should be updated. Using the current default parameters, there are some combinations of indices that never can exceed defined alarm severity thresholds. The conclusions in this thesis have been documented in an online help that also includes simple user instructions for how the results from CLAM should be interpreted. The results have been analyzed together with the staff at Södra Cell Mörrum in order to validate that they are correct and relevant from a user perspective. It was found that the results are correct, but there are some things that can be improved in order to make CLAM more user friendly.

A successive approximation register (SAR) circuit is adopted to control the digital delay line in the delay-locked loop (DLL) to achieve very fast locking effect in this proposed thesis. And in order to get low power consumption results, a loop state controller (LSC) is utilized to disable most of circuit. Because it is more easily to design and the advantages of high stability of delay-locked loop (DLL) compared to phase-locked loop (PLL), delay-locked loop (DLL) is more widely used in the adjustment of the clock error in the high frequency situation. This proposed delay locked loop (DLL) is added a register and a multiplexer in the feedback path. And the multiplexer does select which n-bit digital control code shall be read into the delay line; as the loop is locked, the path goes through the register is chosen to enter the sleep state ,and disable part of the circuit to make it into power saving mode. When entering the sleep state, the register provides the fixed input code; the phase error comparator (PEC) will keep tracking whether the frequency changes due to process, voltage, temperature and load (PVTL) variation uninterruptedly. Once there is something changed, the PEC will send a signal to inform the loop state controller (LSC) to enable the circuit from the sleep state, when the clock has to be locked again. And it just has 6 cycles time to relock, the lock range is form 150MHz to 900MHz. The power consuming are 15mW in lock mode and 9mW in sleep mode.

This thesis establishes a quantization noise model of a delta-sigma modulator (DSM), which is utilized to estimate the phase noise performance of a fractional-N frequency synthesizer. In delta-sigma modulator structures, we choose multi-stage noise shaping (MASH) and single-loop structure for investigating the advantages and disadvantages. We have implemented a 3rd order single-loop and a 3rd order MASH DSM by using Verilog codes and a Xilinx field-programmable gate-array (FPGA). With a reference frequency of 12MHz, the fractional-N frequency synthesizer has an output frequency band of 2400~2500MHz, and a frequency resolution of 183 Hz. The measured phase noise is lower than -54 dBc/Hz at 10 kHz offset frequency. The PLL settling time is less than 29us with a 48 MHz frequency hopping.

The applicability of CFD codes for two-phase flows has always been limited to special cases due to the very complex nature of its interface. Due to its tremendous computational cost, methods based on direct resolution of the interface are not applicable to most problems of practical relevance. Instead, averaging procedures are commonly used for these applications, such as the Eulerian-Eulerian approach, which necessarily means losing detailed information on the interfacial structure. In order to allow widespread application of the two-fluid approach, closure models are required to reintroduce in the simulations the correct interfacial mass, momentum, and heat transfer. It is evident that such closure models will strongly depend on the specific flow pattern. When considering vertical pipe flow with low gas volume flow rates, bubbly flow occurs. With increasing gas volume flow rates larger bubbles are generated by bubble coalescence, which further leads to transition to slug, churn-turbulent, and annular flow. Considering, as an example, a heated tube producing steam by evaporation, as in the case of a vertical steam generator, all these flow patterns including transitions are expected to occur in the system. Despite extensive attempts, robust and accurate simulations approaches for such conditions are still lacking. The purpose of this dissertation is the development, testing, and validation of a multifield model for adiabatic gas-liquid flows at high gas volume fractions, for which a multiple-size bubble approach has been implemented by separating the gas structures into a specified number of groups, each of which represents a prescribed range of sizes. A fully-resolved continuous gas phase is also computed, and represents all the gas structures which are large enough to be resolved within the computational mesh. The concept, known as GENeralized TwO Phase flow or GENTOP, is formulated as an extension to the bubble population balance approach known as the inhomogeneous MUltiple SIze Group (iMUSIG). Within the polydispersed gas, bubble coalescence and breakup allow the transfer between different size structures, while the modeling of mass transfer between the polydispersed and continuous gas allows including transitions between different gas morphologies depending on the flow situations. The calculations were performed using the computational fluid dynamic code from ANSYS, CFX 14.5, with the support of STAR-CCM+ v8.06 and v9.02. A complete three-field and four-field model, including a continuous liquid field and two to three gas fields representing bubbles of different sizes, were first tested for numerical convergence and then validated against experimental data from the TOPFLOW and MT-Loop facilities.

This thesis investigates using processor-in-loop techniques with non-real-time electro-magnetic transient simulation software for designing microcontroller-based systems. The behaviour of a microcontroller is included in the simulation by directly integrating the target microcontroller into an EMTP co-simulation. Additionally, to assist the design process, the optimization functionality of the EMTP program is extended to the microcontroller algorithm. Since non-realtime simulation does not require specialized test hardware to accurately simulate systems, it is both cheaper and able to be used earlier in the controller design process then hardware-in-loop real-time simulation. A component is created in the PSCAD / EMTDC program to integrate a generic controller running an arbitrary periodic algorithm into an EMTP simulation. The component operation is verified by creating a co-simulation of a three-phase induction motor V / f. speed control. The co-simulation results match the behaviour of the resulting system under a fairly broad range of operating conditions, highlighting the applicability of the technique.

This thesis investigates using processor-in-loop techniques with non-real-time electro-magnetic transient simulation software for designing microcontroller-based systems. The behaviour of a microcontroller is included in the simulation by directly integrating the target microcontroller into an EMTP co-simulation. Additionally, to assist the design process, the optimization functionality of the EMTP program is extended to the microcontroller algorithm. Since non-realtime simulation does not require specialized test hardware to accurately simulate systems, it is both cheaper and able to be used earlier in the controller design process then hardware-in-loop real-time simulation. A component is created in the PSCAD / EMTDC program to integrate a generic controller running an arbitrary periodic algorithm into an EMTP simulation. The component operation is verified by creating a co-simulation of a three-phase induction motor V / f. speed control. The co-simulation results match the behaviour of the resulting system under a fairly broad range of operating conditions, highlighting the applicability of the technique.

As unidades industriais de produção de poliolefinas operam de maneira contínua, mas precisam produzir diferentes tipos de grades poliméricos (polímeros com diferentes especificações, para diferentes aplicações). As condições de operação do reator são mantidas por um certo período de tempo para produzir um determinado grade, e periodicamente as condições são alteradas para produzir lotes de outros grades. Estas transições permitem produzir diferentes grades usando o mesmo reator, mas exige mudanças nas condições operacionais e, como consequência, o polímero produzido durante uma transição fica fora da especificação. Assim, é desejável que as transições sejam realizadas no menor tempo possível, de maneira a produzir a menor quantidade de polímero fora da especificação. Estratégias mais eficientes de operar a transição podem ser obtidas através da solução de um problema de otimização dinâmica. Neste trabalho uma função objetivo integral quadrática foi minimizada, utilizando técnicas sequenciais dinâmicas para resolução da otimização. Os resultados foram primeiramente simulados e depois otimizados para a homopolimerização e copolimerização. No caso da homopolimerização, as otimizações mostraram que para aumentar o MI é preciso aumentar a concentração de hidrogênio na alimentação. Já na copolimerização, para aumentar o MI foi preciso diminuir a concentração de hidrogênio na alimentação e aumentar a vazão de comonômero; e para diminuir a densidade foi preciso aumentar a vazão de comonômero. Observou-se que as propriedades instantâneas têm dinâmica mais rápida e agressiva que as cumulativas. Os resultados mostraram que quando a parametrização não era adequada a solução se afastava do ótimo. Foi possível notar que atuar durante 2 tempos de residência já traz uma redução significativa do tempo para o término da transição e da massa de produto fora da especificação. O perfil das propriedades da transição no sentido grade 1 - grade 2 se mostrou diferente do grade 2 - grade 1, concluindo que o perfil de uma transição depende fortemente da direção da mudança nas propriedades. / Polyolefin plants operate under continuous production, but they need to supply many types of polymer grades (polymer with different specification, used in different applications). The operating conditions are maintained constant during the production of a certain grade and need to change periodically to produce another grade. Grade transitions allow the production of different polymer grades in a single reactor, but as they require changes in the operating conditions, there is a large production of off-specification polymer. Therefore, a desired transition drives the polymer properties to the new grade in a short period of time, producing a small amount of off-specification polymer. Efficient strategies to operate the transition can be obtained by solving a problem of dynamic optimization. In this work, a quadratic integral objective function was minimized by using dynamic sequential techniques for solving optimization. The results were first simulated and then optimized for the homopolymerization and copolymerization. In the case of homopolymerization, optimizations showed that to increase the MI is necessary to increase the hydrogen concentration in the feed. In the copolymerization, to increase the MI was necessary to reduce the concentration of hydrogen in the feed and increase the comonomer flow rate; and to decrease the density was necessary to increase the comonomer flow rate. It was observed that the instantaneous properties have faster and aggressive dynamics compared to the cumulative properties. The results showed that when the parameterization was not adequate the solution moves away from the optimum. It was observed that to act for 2 residence times makes a significant reduction in the transition time completion and in the mass of product out of specification. The trajectories of the transition properties towards grade 1 - grade 2 showed different behavior compared to grade 2 - grade 1 transition, concluding that the profile of a transition depends strongly on the direction of change in the properties.