O desenvolvimento do processo de acumulação de capital fez com que o sistema capitalista sofresse grandes modificações em suas leis de movimento e se ultrapassasse seu estágio concorrencial, apresentando agora na maioria dos seus mercados características típicas de monopólio, o que fez com que se denominasse este estágio de capitalismo monopolista. As economias maduras sob a égide do capitalismo monopolista trazem consigo uma tendência a gerar uma quantidade maior de excedente do que alternativas para o seu investimento em atividades produtivas. Isto faz com que o sistema carregue consigo uma tendência inerente a estagnação, que só é contida por poderosos estímulos contrários, que impulsionam a economia enquanto seu efeito perdura, deixando novamente os sintomas da estagnação visíveis quando se esvanecem. Dentre estes estímulos contra tendentes, a financeirização, ou o desvio do excedente da esfera produtiva para a financeira, se tornou a mais poderosa força do capitalismo em sua luta contra a estagnação. / The development process of capital accumulation has made the capitalist system suffered major changes in its laws of motion and exceeded its competitive stage, representing the majority of its markets typical of monopoly, which led them to call this stage of monopoly capitalism. The mature economies under the auspices of monopoly capitalism brings with it a tendency to generate a greater amount of surplus that alternatives for its investment in productive activities. This causes the system to load with an inherent tendency to stagnation, which only contained a powerful stimulus to the contrary, that drive the economy while its effect lasts, leaving again the symptoms of stagnation visible when vanish. Among these stimuli aimed against the financialisation, or diversion of the surplus from the productive sphere to the financial, became the most powerful force of capitalism in their struggle against stagnation.

nÃo hà / This work was developed with the aim of contributing to the discussion about the impact of the public debt on the economic growth of the OECD countries. Different theoretical and empirical work suggest an effect of economic stagnation when there is an increase in the debt, however, and on the other hand, many authors argue that a rise in the growth strengthens the economy by attracting new investors. There is no consensus in the literature on the subject. This work was developed with the main purpose to provide data that may help clarify the debt and growth paradox. To capture the direction of those two variables as well as the mutual influence of this movement, we used in our study an econometric vector auto-regressive type model â VAR, with annual data from 16 out of the 32 countries considered as advanced economies that make up the Organization for Economic Cooperation and Development â OECD, during the period from 1995 to 2011. The results presented indicate a weak causality going from growth to debt. Thresholds concerning public debt have not been identified. It has been found out that a low economic growth of the countries within the sample, under the Granger sense, causes bigger Debt/GDP ratios. / Este trabalho foi elaborado com o objetivo de contribuir com a discussÃo sobre o impacto da dÃvida pÃblica no crescimento econÃmico nos paÃses da OCDE. Diferentes trabalhos teÃricos e empÃricos propÃem um efeito de estagnaÃÃo da economia quando hà uma elevaÃÃo da dÃvida, entretanto e, por outro lado, muitos autores defendem que uma elevaÃÃo no crescimento fortalece a economia atraindo novos investidores. NÃo hà consenso na literatura sobre o assunto. Com a finalidade principal de fornecer dados que possam ajudar a esclarecer o paradoxo dÃvida e crescimento este trabalho foi desenvolvido. Para capturar a direÃÃo destas duas variÃveis, bem como a influÃncia mÃtua deste movimento, no nosso estudo foi utilizado um modelo economÃtrico do tipo autorregressivo vetorial â VAR, com dados anuais de 16 dos 32 paÃses considerados de economia avanÃada que compÃem a OrganizaÃÃo para CooperaÃÃo e Desenvolvimento EconÃmico â OCDE, durante o perÃodo de 1995 a 2011. Os resultados apresentados indicam uma fraca causalidade indo do crescimento para dÃvida. NÃo foram encontrados limiares para dÃvida pÃblica. Foi encontrado que um baixo crescimento econÃmico dos paÃses da amostra causa, no sentido de Granger, maiores razÃes DÃvida/PIB.

O desenvolvimento do processo de acumulação de capital fez com que o sistema capitalista sofresse grandes modificações em suas leis de movimento e se ultrapassasse seu estágio concorrencial, apresentando agora na maioria dos seus mercados características típicas de monopólio, o que fez com que se denominasse este estágio de capitalismo monopolista. As economias maduras sob a égide do capitalismo monopolista trazem consigo uma tendência a gerar uma quantidade maior de excedente do que alternativas para o seu investimento em atividades produtivas. Isto faz com que o sistema carregue consigo uma tendência inerente a estagnação, que só é contida por poderosos estímulos contrários, que impulsionam a economia enquanto seu efeito perdura, deixando novamente os sintomas da estagnação visíveis quando se esvanecem. Dentre estes estímulos contra tendentes, a financeirização, ou o desvio do excedente da esfera produtiva para a financeira, se tornou a mais poderosa força do capitalismo em sua luta contra a estagnação. / The development process of capital accumulation has made the capitalist system suffered major changes in its laws of motion and exceeded its competitive stage, representing the majority of its markets typical of monopoly, which led them to call this stage of monopoly capitalism. The mature economies under the auspices of monopoly capitalism brings with it a tendency to generate a greater amount of surplus that alternatives for its investment in productive activities. This causes the system to load with an inherent tendency to stagnation, which only contained a powerful stimulus to the contrary, that drive the economy while its effect lasts, leaving again the symptoms of stagnation visible when vanish. Among these stimuli aimed against the financialisation, or diversion of the surplus from the productive sphere to the financial, became the most powerful force of capitalism in their struggle against stagnation.

Fluid jet polishing (FJP) is a new advanced polishing technology that finds applications in many industries, especially in the optics industry. With the broad application of various surfaces in optics, the sub-micrometric scale and the nanometric surface roughness accuracy are major challenges. Fluid jet polishing is a technology developed from abrasive water jet machining. This technology is a water jet cutting technology, which uses high-pressure flow to cut/remove materials. In this thesis, the working principle, and simulations, as well as verification of fluid jet polishing are thoroughly investigated. The verification of fluid jet polishing in this thesis includes velocity distribution and material removal derivations. The amount of material removed is directly related to the impact velocity of a particle with a surface, which helps define its abrasive particle velocity. During polishing, the particles travel in a solution called slurry. Due to the relatively similar velocity of the particles and the slurry, the particles and the slurry are assumed to be traveling at the same rate. In this thesis, three specific examples are investigated through the creation of an advanced model using FLUENT, a computational fluid dynamics software. The model simulates the particle path during the fluid jet polishing process, and this thesis compares the simulation results to prior analytical and experimental results. The results indicate that the fluid jet polishing erosion area at a particular location is axisymmetric when the 2D cross-section shape is investigated. As the impingement angle of the fluid jet is reduced, the center dead area, where no polishing is observed, approaches zero. vii Additionally, the horizontal component of the velocity vector initially increases then decreases as one moves away from the center stagnation point. Finally, this thesis demonstrates that the erosion depth into the surface that is polished increases when the working pressure of the fluid is increased. This thesis finds that when the distance between the fluid jet and the workpiece is 7 mm, material removal is maximum.

Sammandrag   Föreliggande uppsats handlar om fossilisering. Fossilisering är ett begrepp som belyser andraspråksinlärares avstannade språkutveckling. Syftet med uppsatsen är att undersöka vilken språksyn som ligger bakom fossilisering och hur det definieras samt hur forskningen har använt begreppet. Fossilisering myntades av lingvisten Larry Selinker 1972. Uppsatsen är en litteraturstudie vars mindre format har frambringat ett antal avgränsningar särskilt när det gäller val av litteratur. Detta har framför allt fått konsekvenser som innebär att uppsatsen endast kan betraktas som ett nedslag i forskningen i och kring begreppet fossilisering.     Fossilisering är en slutstation i en andraspråksinlärares försök att lära sig ett andraspråk. Om en talares andraspråk har fossiliserats finns det fortfarande markanta influenser och rester kvar av modersmålet när det gäller sådant som grammatiska strukturer, uttal och ordval. Andra liknande termer inom andraspråksforskningen är stagnation eller partiell fossilisering. I slutdiskussionen försöker jag att kritiskt diskutera fossilisering. Fossilisering är ett vedertaget men problematiskt begrepp ur en rad synvinklar. Dock används begreppet fortfarande både i snäv och vid betydelse. I sin vidaste mening är 95% av alla andraspråksinlärare fossiliserade.   Nyckelord: Andraspråksinlärning, Fossilisering, Stagnation, Interimspråk, Selinker,

Major cavitation damages can seriously endanger the stability of hydraulic structures, in worst case lead to dam failure. To remedy the effect of cavitation on spillway chutes the most common method today is aeration of the flow. Aerators introduce air to the bottom layers of the flow, enough to prevent damages to occur in the concrete lining. The design of an aerator system is of a complex manner due to the many involving parameters such as the channel slope, ramp angle, Froude number, flow velocity. In this report the susceptibility of the Höljes Dam to cavitate has been outlined with the result that this would occur at an extreme and most unlikely situation and remedial measures have been proposed. The design of an aerator system has been proposed as the result from theoretical research. A physical hydraulic model to assess the efficiency of a proposed aerator design is highly recommended. Alternative causes to the damages observed in the spillway chute are discussed.

The adhesive mechanism is one of the most significant degradation processes of the edge in metal cutting. Although knowledge about adhesion and edge buildup (BUE) has increased in recent years, there are still areas that are less explored. The adhesion has a regularity in the form of clusters: In a cluster, the chips vibrates with a certain frequency. The frequency varies with several influencing factors. In this thesis, a possible connection between acoustic signals and wear of the cutting edge is researched. Audio signals from cutting edges with varied wear must be analyzed. To investigate the adhesive mechanism, the machining process turning will be used. The cutting edge is analyzed optically with a microscope. According to previous research, the adhesive wear has been shown to be mostly dependent on the cutting speed. The size of the stagnation zone depends largely on the friction angle and the shear plane angle, where the friction angle changes depending on the rake angle and the shear plane angle changes depending on the cutting speed. Adhesion wear has been shown to be a fatigue process. This thesis aims to investigate the development of the adhesive mechanism towards the wear status of the tool. The end goal is to construct a model that explains what happens in the wear zones on the edge and to detect changes in the acoustic signal from the cutting zone that occurs during adhesion wear. The cutting zone sound from two cutting tools with different cutting times is used in Fourier analysis. Insert number two will be worked until chipping occurs and examined optically with a microscope between each cycle to verify if chipping was present. One chip was examined after each cycle under a microscope to see if residues from the insert got stuck on the chips. Cycle number one with insert number one (new edge) shows no clear adhesive mechanism while cycle number one with insert number two shows a clear adhesive mechanism. The same cutting speed is achieved during cycle number five and number 18 with cutting tool number two. The frequency increases 11% and the amplitude decreases 42% from cycle number 5 to cycle number 18. Chipping occurred in cutting tool number two after 25 cycles. The frequency of the adhesive mechanism increases, and the amplitude decreases when the insert wears. A reasonable hypothesis is that the surface that is welded together becomes larger with increased wear: The spring in the adhesive system becomes stronger while the mass remains constant. A hypothesis that the amplitude of the adhesive mechanism is low during cycle number one with insert number one may be due to the fact that the workpiece used was at room temperature. No significant degeneration has occurred of the chip surface.

Simulation of a wall jet in an enclosure performed to predict the effect of pulsation flow on improving the performance of mixing ventilation systems which are routine practices in industry. Comparing two flows with equal amount for constant and pulsation modes, it was found out that the same global airflow pattern exists for both of the cases but with generation of more eddies and local periodically velocity variations for pulsation mode. This periodic generation of turbulence at pulsatile ventilation flows happen despite the relatively low Reynolds numbers of such flows.Bigger size of boundary layer and higher turbulent kinetic energy for pulsation mode in comparisonwith the same flow rate in constant velocity mode could result in more ventilation capacity with no need to increase the use of energy. It was seen that while a higher constant velocity rate could produce the same acceptable results in terms of higher efficiency in ventilation, a lower pulsated flow could yields it without the risk of draught. Regarding the thesis procedure, the computational solution started with a grid independency study. 2-Dimensional simulation failed to simulate the results similar to the experimental data. No URANS model was able to yield good outcome in 2D mode. The study was continued with 3D SST-kω which yielded good prediction of velocity profiles near the wall regions. For predicting turbulence parameters in the center of the domain SST-URANS was not helpful so, simulation switched to SAS which was successful to some extent to get close to reality.

No description available.

<p>Experiments were performed to study the effect of surface finish and jet velocity on the boiling performance at the stagnation point under a free liquid planar jet. A rectangular jet with dimensions 9 mm x 1 mm was used to impinge subcooled water on the center of a copper surface 8 mm width x 20 mm length. Jet velocities ranged from 0.9 to 2.5 m/s while the degree of subcooling was kept constant at 10 °C.</p> <p>Three surfaces were prepared using emery paper #1200, #500 and #320 and the arithmetic mean square of the roughness <strong>Ra</strong> = 18.72, 401.65 and 533.53 nm.</p> <p>Increasing the jet velocity has shown to increase the heat flux slightly in the single phase regime. Also by increasing the jet velocity, boiling was found to start at higher surface superheat achieving higher values of burn out heat flux BOF for jet velocities V_j ≤ 1.5 m/s. This trend agrees with studies reported in literature. Some contradicting results occurred at higher jet velocities which is attributed to the flow profile.</p> <p>For jet velocities lower than 2 m/s, the surface with higher <strong>Ra </strong>was found to have a delayed Onset of Nucleate Boiling ONB, higher Burn out Heat Flux BOF, and lower rate of heat transfer in the single phase regime. Surface finish did not show significant effect on boiling performance at higher jet velocities. The contradictions observed at jet velocities higher than 1.5 m/s were attributed to the flow profile. Results regarding the effect of surface finish on heat transfer in the single phase regime under liquid jet impingement were compared to literature and a reasonable agreement was found. More studies are needed to explain the contradictions found for higher jet velocities.</p> / Master of Applied Science (MASc)