Mixing

... School of Engineering Springfield, Massachussetts Drag Reduction and Wake Minimization on Marine Vehicles ,,P. ,3 1991 By: , Craig A. Hunter Pasquale Delore Walter M. Presz, Jr. Final Report Office of Naval Research Grant N0014-89-J-1883 00 July 1991 I I Page 2. Abstract ...

Epoxidized natural rubber–alumina nanoparticle composites were prepared by melt compounding with an internal mixer for a constant filler loading of 10 phr. Mixer parameters such as the mixing temperature, mixing time, and rotor speed were screened and optimized with response surface methodology to maximize the impact strength. The parameters were selected as three independent variables and the impact strength (J/m) was selected as the response in a screening factor study. The mixing temperature and its interaction terms were identified as insignificant factors with a P value greater than 0.0500. The optimum calculated values of the tested variables (rotor speed and mixing time) for the maximum impact strength were found to be a rotor speed of 60 rpm and a mixing time of 6 min with a predicted impact strength of 208.88 J/m. These predicted optimum parameters were tested in real experiments. The final impact strength was found to be close to the predicted value of 215.84 J/m, with only a 3.33% deviation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Metal matrix composites with high interface density are produced via severe plastic co-deformation of multiphase alloys. 1–15 Corresponding compounds are first prepared by liquid or powder metallurgy3–12 or through restacking solids of different composition. 2 Subsequent extreme straining, to promote intense microstructure refinement, proceeds by wire drawing, ball milling, accumulative roll bonding, damascene forging, equal channel angular extrusion, friction, or highpressure torsion. 7

The authors have evaluated the emulsification of oil of varying viscosities for concentrated o/w emulsions (>60%). Rushton type impellers and baffled mixing vessels were used. The emulsions were prepared in the transition regime (80 < Re < 200). It was found that, when the oil content increases, it is the emulsion viscosity that controls droplet size, regardless of the dispersed phase viscosity and hydrodynamics. The authors have followed an experimental procedure that allows for the scale-up of the results.

Correlations are presented to compute the mutual solubilities of CO2 and chloride brines at temperatures 12–300°C, pressures 1–600 bar (0.1–60 MPa), and salinities 0–6 m NaCl. The formulation is computationally efficient and primarily intended for numerical simulations of CO2-water flow in carbon sequestration and geothermal studies. The phase-partitioning model relies on experimental data from literature for phase partitioning between CO2 and NaCl brines, and extends the previously published correlations to higher temperatures. The model relies on activity coefficients for the H2O-rich (aqueous) phase and fugacity coefficients for the CO2-rich phase. Activity coefficients are treated using a Margules expression for CO2 in pure water, and a Pitzer expression for salting-out effects. Fugacity coefficients are computed using a modified Redlich–Kwong equation of state and mixing rules that incorporate asymmetric binary interaction parameters. Parameters for the calculation of activity and fugacity coefficients were fitted to published solubility data over the P–T range of interest. In doing so, mutual solubilities and gas-phase volumetric data are typically reproduced within the scatter of the available data. An example of multiphase flow simulation implementing the mutual solubility model is presented for the case of a hypothetical, enhanced geothermal system where CO2 is used as the heat extraction fluid. In this simulation, dry supercritical CO2 at 20°C is injected into a 200°C hot-water reservoir. Results show that the injected CO2 displaces the formation water relatively quickly, but that the produced CO2 contains significant water for long periods of time. The amount of water in the CO2 could have implications for reactivity with reservoir rocks and engineered materials.

A 3-D two-fluid CFD model in the Eulerian-Eulerian framework was developed to predict the hydrodynamics and heat and mass transfer of sieve trays. Interaction between the two phases occurs via interphase momentum and heat and mass transfer. The tray geometries are ...

An integrated micro/nano-fluidic system is presented for protein analysis. It is comprised of an integrated micromixer (IMM) and a preconcentrator with a separation column. The passive and planar type of IMM is based on an unbalanced split and the cross collision of the fluidic streams. The IMM can be easily fabricated and integrated to the microfluidic system. The preconcentrator has nanochannels formed by the electrical breakdown of polydimethylsiloxane (PDMS) membrane by applying a high electrical shock, but without any nano-lithography. The integrated microdevice was used for sample preparation (mixing with tagging molecules) and subsequent concentration of proteins. Proteins were electrokinetically trapped near the junction of the micro/nanochannels. We show a conceptual design and a simple microfluidic system for purposes of mixing and preconcentration. Figure Mixing and preconcentration of dissolved proteins using an integrated micro/nano-fluidic system

The purpose of this project is to document and demonstrate a selection of equalisation and techniques applied in the various stages of music production. The Equaliser techniques I decided to look into with my project are as follows: Parametric Equaliser, Graphic Equaliser, Mid/Side Equalisation, Side Chain Equaliser and Parallel Processing with Equalisation. I have various accompanying practical examples that I have produced by myself which will demonstrate the effectiveness of the equalisers and techniques. The project’s aim is to enhance my own skills and insights but also those how may read this study. This should provide them with better insight into how beneficial an equaliser can be in terms of assisting both amateurs and professionals to create professional, industry- sounding projects.

For the cultivation of microorganisms, baffled shake flasks are employed when increased levels of oxygenation and mixing are required. Their use has been discouraged, however, due to the danger of a wetted sterile plug and the lower reproducibility of the experimental results. Consequently, there are only few studies dealing with this type of shaken bioreactor, and there is practically no characterization of this reactor type from a chemical engineering viewpoint. Therefore, a systematic study to elaborate the basic characteristics of the volumetric power consumption and the unfavorable out-of-phase phenomenon in baffled shake flasks is undertaken. A new type of measuring device was developed to measure the volumetric power consumption in a single shake flask. The volumetric power consumption was found to increase with increasing shaking frequency and with decreasing filling volume. Further, an independency of power consumption on the shaking diameter was observed as long as the fluid motion is in-phase. A comparison of two different baffle geometries demonstrated that deeper baffles cause more resistance to fluid flow. For the commonly employed shaking diameter of 25 mm, the investigated baffled flask types may not be operated in the in-phase state. A larger shaking diameter must therefore be employed. It was found for the first time that for all in-phase conditions, the dimensionless Newton number Ne′Ne′ is independent of the Reynolds number Re. Power consumption in baffled shake flasks may therefore be described by a characteristic Ne′Ne′ only dependent on the filling volume VLVL and the flask type. Even though there are quantitative differences, a qualitative similarity between fluid flow in stirred tanks and shake flasks has been demonstrated.

The detection of concealed weapons at a distance is a critical security issue that has been a great challenge for different imaging approaches. In this paper we discuss the use of ultrasonics in a novel way to probe for metallic and non-metallic materials under clothing. ...

Computational fluid dynamics is recognized as a powerful engineering tool. That is, CFD has advanced over the years to the point where it can now give us deep insight into the analysis of very complex processes. There is a danger, though, that an engineer can place too much confidence in a simulation. If a user is not careful, it is easy to believe that if you plug in the numbers, the answer comes out, and you are done. This assumption can lead to significant errors. As we discovered in the course of a study on behalf of the Department of Energy's Salt Disposition Integration Project at the Savannah River Site in Aiken, S.C., CFD models fail to capture some of the large variations inherent in complex processes. These variations, or scatter, in experimental data emerge from physical tests and
are inadequately captured or expressed by calculated
mean values for a process. This anomaly between
experiment and theory can lead to serious errors in
engineering analysis and design unless a correction
factor is experimentally validated. For this study,
blending times for the mixing of salt solutions in large
storage tanks were the process of concern. Radioactive liquid waste is stored at the Savannah River Site in 47 underground storage tanks that vary in capacity from 850,000 to 1.3 million gallons.

In order to resolve oil mixtures and for oil-source correlation purposes, both hydrogen (d2H) and carbon isotope compositions (d13C) of n-alkanes and acyclic isoprenoid alkanes have been determined in petroleum mixtures and extracts from Jurassic source rocks of distinct organic matter type, depositional setting and lithology in the South Viking Graben, Norway. d2H values vary from -80 to -140‰ for n-alkanes and from -130 to -165‰ for pristane (Pr) and phytane (Ph) in oil and condensate samples. At the same maturity level, in the main oil generative window, individual n-alkanes from most oils and condensates show a 2H-enrichment with n-alkane chain length by 15 to 50‰. With the increase in the estimated input of hydrocarbons from terrigenous source material to petroleum mixtures, the n-alkanes (>C20) exhibit a higher 2 H-enrichment while n-alkanes (C10-C14) show a higher 13C-enrichment. d2H values of n-alkanes (>C20) are useful to discriminate mixed oils that were not well differentiated by d13C data. d2H values of individual n-alkanes from oils suggest a possible exchange of C-bound H with other hydrogen during their generation from precursor molecules. We find that d2H values of n-alkanes from Jurassic source rock extracts, at the onset of oil generation, were mainly controlled by the isotopic composition of biosyn-thetic precursors and varied from -100 to -150‰. Combination of carbon and hydrogen isotope compositions of n-alkanes proved to be a useful tool to discriminate Jurassic petroleum mixtures from distinct sources in the Norwegian South Viking Graben.

Water-column mixing is known to have a decisive impact on plankton communities. The underlying mechanisms depend on the size and depth of the water body, nutrient status and the plankton community structure, and they are well understood for shallow polymictic and deep stratified lakes. Two consecutive mixing events of similar intensity under different levels of herbivory were performed in enclosures in a shallow, but periodically stratified, eutrophic lake, in order to investigate the effects of water-column mixing on bacteria abundance, phytoplankton abundance and diversity, and rotifer abundance and fecundity. When herbivory by filter-feeding zooplankton was low, water-column mixing that provoked a substantial nutrient input into the euphotic zone led to a strong net increase of bacteria and phytoplankton biomass. Phytoplankton diversity was lower in the mixed enclosures than in the undisturbed ones because of the greater contribution of a few fast-growing species. After the second mixing event, at a high biomass of filter-feeding crustaceans, the increase of phytoplankton biomass was lower than after the first mixing, and diversity remained unchanged because enhanced growth of small fast-growing phytoplankton was prevented by zooplankton grazing. Bacterial abundance did not increase after the second mixing, when cladoceran biomass was high. Changes in rotifer fecundity indicated a transmission of the phytoplankton response to the next trophic level. Our results suggest that water-column mixing in shallow eutrophic lakes with periodic stratification has a strong effect on the plankton community via enhanced nutrient availability rather than resuspension or reduced light availability. This fuels the basis of the classic and microbial food chain via enhanced phytoplankton and bacterial growth, but the effects on biomass may be damped by high levels of herbivory.