This thesis is a measurement evaluation type of project in which to perform a harmonic response analysis were the results will be compared to measurement data to verify if the ANSYS model is realistic in terms of dynamics. This includes proposing the different parameters that will affect the results of the comparison as well as how to improve further models. In 2014 Atlas Copco received a special customer order of a ST1530 loader with a Detroit engine instead of a Cummins engine which is commonly used in the ST1530. New dynamic analyses had to be performed by the Applied Mechanics Group, regarding harmonic response using data from a measurement of a ST1520 loader with a Detroit engine. A new design of the engine cradle was developed after several analysis iterations. In February 2015, new measurements were performed on the loader with the right Detroit engine and a new engine cradle. There are two different comparison tools/methods used in this thesis, one that consists of comparing the difference between the mean average value of both the ANSYS and the measurements results. The other tool/method is more accurate since it compares both the variation between the peaks and also the offset of the frequency. Results show that the measurement results in 800 rpm were very compatible with the analysis results in ANSYS, meanwhile at high speed the measurement results were only moderately compatible with the analysis results. The vibration in 800 rpm doesn’t exceed the Atlas Copco rule of thumb as opposed to the 2173 rpm. This is only considering the cradle, the cooler however consists of higher vibrations than the measurement data. Their rule of thumb is defined as a boundary for the maximum allowable vibration values. The model could’ve been a lot more accurate if the use of CAD models of both the engine and the cooler were implemented in the analysis. This is desirable but it does not work all the time as companies for these products can not issue a CAD model due to, e.g. Patents and such. / Denna avhandling är en mätutvärdering där man ska utföra en harmonisk responsanalys vars resultat kommer att jämföras med mätdata för att kontrollera om ANSYS modellen är realistisk i dynamiska termer. Detta inkluderar även att man ska föreslå de olika parametrar som kommer att påverka resultatet av jämförelsen samt hur man kan förbättra ytterligare modeller. Under 2014 erhöll Atlas Copco en speciell kundorder med en ST1530 lastare där man ville ha en Detroitmotor istället för en Cumminsmotor som ofta används i ST1530. Detta resulterar i att nya dynamiska analyser måste utföras av Applied Mechanics Group, angående harmonisk respons där man använde data ifrån en mätning av en ST1520 lastare med Detroit motor. En ny utformning av motorvaggan utvecklades efter flera iterationer. I februari 2015 så utfördes nya mätningar på lastaren med rätt Detroitmotor och den nya motorvaggan. Två olika jämförelseverktyg/metoder användes i denna avhandling. Det första verktyget/metoden testades, som består av att jämföra skillnaden mellan det genomsnittliga medelvärdet av både ANSYS och mätresultat. Det andra verktyget/metoden användes för att den är mer exakt eftersom den jämför både variationen mellan vibrationstopparna och även förskjutningen i frekvens. Resultaten visar att mätresultaten i låg hastighet (800 rpm) var mycket förenliga med analysresultaten i ANSYS, däremot vid hög hastighet (2173 rpm) var mätresultaten bara måttligt förenliga med analysresultaten. Vibrationerna i 800 rpm överstiger inte Atlas Copcos tumregel till skillnad från 2173 rpm, detta är bara med tanke på vaggan. Kylaren har däremot högre vibrationer än mätdata.Denna tumregel är definierad som en avgränsning för maximalt tillåtna vibrationsvärden. Modellen kunde varit mycket mer exakt om man hade implementerat CAD-modeller av både motorn och kylaren i analysen. Detta är önskvärt men funkar inte hela tiden då företagen för dessa produkter inte kan ge ut en CAD modell, pga. t.ex. patent eller liknande.

Die Identifikation von Einflussfaktoren und deren Wirkungsrichtung auf die Kursentwicklung einer Aktie ist von großer Bedeutung für die Finanzmarktanalyse. Die wechselseitigen Zusammenhänge zwischen den Renditen spezifischer Aktien sind solche relevante Informationen. In diesem Beitrag werden die Interdependenzen von Aktienrenditen auf der Grundlage vektorautoregressiver (VAR)-Modelle für kleine, homogene Brachen- und Marktsegmente analysiert. Hierzu wurden die Renditen ausgewählter im Deutschen Aktienindex (DAX) notierter Unternehmen zu drei Branchensegmenten zusammengefasst. Darüber hinaus zeigt sich am Beispiel der Hoechst-Aktie, dass eine gemeinsame DAX-Notierung Einfluss auf das Beziehungsgeflecht der Renditen innerhalb eines Brachensegmentes nimmt.

Distillation is the leading thermal separation technology that is carried out in many industrial tray columns worldwide. Although distillation columns are expensive in terms of cost and energy, they will remain in service due to unavailability of any equivalent industrially-viable alternative. However, rising energy costs and urgent needs to reduce greenhouse gas emissions demand improvements in the energy efficiency of separation processes, globally. This can be achieved by tuning the dynamics of the evolving two-phase dispersion on column trays via design modification and revamping. Thus, it becomes necessary to understand how the two phases evolve over the tray and how they link to tray efficiency for given tray designs, systems and operating conditions. Only then, the cost and energy reduction can be achieved by strategically iterating the tray design and revamps with respect to the resulting tray efficiency. To pursue this strategy, accurate prediction of the separation efficiency based on flow and mixing patterns on the trays is an important prerequisite. In this thesis, the mathematical models relying on flow and mixing patterns for predicting the tray efficiencies were reviewed. These models were developed based on the analyses of two-phase flow, crossflow hydraulics and mass transfer over the trays. Several limitations in the existing models were identified that could lead to inaccurate tray efficiency predictions. First, the conventional models do not account for any variation in the local two-phase flow in their formulation. These models rather consider a homogeneous flow scenario based on flow monitoring at the tray boundaries only, which indicates a black box efficiency estimation. Second, the existing models do not consider any vapor flow maldistribution, which can be detrimental to the tray efficiency. In response to these limitations, a new model based on refinement of the conventional residence time distribution (RTD) model (referred to as the ‘Refined RRTD model’) was proposed. The new model involves geometric partitioning of the tray into compartments along the flow path length, which permits computing the tray efficiency through quantification of the efficiency of the individual compartments. The proposed model ensures that the fluid dynamics of each compartment contribute towards the overall tray efficiency, which specifically targets the black box prediction of the tray efficiency by the conventional models. The tray discretization further aids in analyzing the impact of vapor flow maldistribution on the tray efficiency. In the initial assessment, the new model capabilities were demonstrated in appropriate case studies after theoretical validation of the model for the limiting cases of the two-phase flows. For the experimental validation of the new model, a full hydrodynamic and mass transfer description of the two-phase dispersion specific to the tray operation is indispensable. Because of the inherently complex dispersion characteristics, significant advancements in the imaging and efficiency modeling methods were required. In this thesis, a DN800 column simulator equipped with two sieve trays (each with 13.55% fractional free area) was used with air and tap water as the working fluids. Deionized water was used as a tracer. The gas loadings in the column in terms of F-factor were 1.77 Pa0.5 and 2.05 Pa0.5, whereas the weir loadings were 2.15 m3m-1h-1, 4.30 m3m-1h-1 and 6.45 m3m-1h-1. An advanced multiplex flow profiler comprising 776 dual-tip conductivity probes for simultaneous conductivity measurements was introduced for hydrodynamic characterization. The spatial resolution of the profiler based on the inter-probe distance was 21 mm × 24 mm, whereas the temporal resolution was 5000 Hz. The design characteristics of the new profiler, electronic scheme, measurement principle, reference framework, and data processing schemes are explained in detail. By analyzing the two-phase dispersion data gathered by the profiler at multiple elevations above the tray, the effective froth height distributions were obtained for the first time based on a newly proposed approach. Uniform froth heights were seen over the majority of the tray deck, whereas both minimum and maximum froth heights were detected immediately after the tray inlet. Based on threshold-based calculation (accompanied by γ-ray CT scans), 3D time-averaged liquid holdup distributions were visualized for the first time, too. Homogeneous liquid holdup distributions were observed at multiple elevations above the deck with the highest holdups occurring near the average effective froth heights. The detailed flow and mixing patterns of the liquid in the two-phase dispersion were retrieved via tracer monitoring. With respect to tray centerline, axisymmetric liquid flow and mixing patterns were detected with parabolic velocity distributions near the tray inlet. The liquid velocities over the remaining tray deck were nearly uniform for the prescribed loadings. Eventually, the RRTD model was applied by discretizing the tray geometrically, and accordingly employing the available hydrodynamic data. The conventional models often applied in the literature were also evaluated with the new model. For evaluating the model predictions, a new system add-on for the existing air-water column facility was proposed for direct efficiency measurements. The air-led stripping of isobutyl acetate from the aqueous solution is a safe and viable approach that overcomes numerous limitations posed by the existing chemical systems. Based on liquid sampling at different tray locations, the liquid concentration distributions were obtained at each operating condition via UV spectroscopy. The tray and point efficiencies as well as stripping factors were calculated from those distributions. Because of the low liquid diffusivity and high liquid backmixing, low efficiencies were observed at the given loadings. The model predictions were consistent with the experimental counterparts (even for the extrapolated values of the involved parameters), because of the uniform liquid flow and mixing in the compartments. For the given predictions, those corresponding to the new RRTD model were the most accurate. Additional hydrodynamic and efficiency data are needed for more conclusive evidence regarding the promise of the RRTD model.