of time. It is obtained through statistical analysis using the power spectral density (PSD) technique. This involves the computation of the Fourier Transform of the auto correlation sequence of the time series from either plane. As the gas superficial velocity increases, slug frequency increases. This is in agreement with . The bubble frequencies for both 5 and 100 mPa.s were quite close most especially at a gas superficial velocity of 0.17 to 0.361 m/s. This range indicates a developing slug and the number of slugs at this region are the same. With an increase of viscosity from 5 to 5000 mPa.s, slug frequency can be observed to decrease. This is accounted for by the dominating effect of viscous forces over inertia forces. This constitutes the viscous effect which leads to an increase in drag force and a subsequent decrease in the bubble rise velocity, with the length of slug unit increasing due to coalescence, hence a decrease in bubble frequency as liquid viscosity increases. This is contrary to what was proposed by . This is probably due to the use of horizontal pipe. The length of slug unit increases with an increase in viscosity which reduces the amount of bubbles captured within the sensor’s cross-section over a period of time (bubble frequency).
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To reduce the damage caused by the sloshing, many studies of sloshing have been conducted with water as the working fluid. On the other hand, the effects of viscosities of liquids other than water on sloshing are rarely reported. Many works have been devoted to the investigation of the effect of baffles on reducing the sloshing effects. However, the mechanism whereby sloshing due to the baffles and liquid viscosity is damped is not fully understood. In the present study, the effects of varying the external excitation amplitude and the number of vertical baffles on sloshing in a rectangular tank were examined both experimentally and numerically. The vertical baffles are fixed to the bottom of a tank, which is excited with a given excitation frequency. To investigate effects of the viscosity of the liquid, two fluids are considered: water and sunflower oil. Section Ⅱ introduces the experimental method. Section Ⅲ describes the numerical and experimental results, and Section Ⅳ presents the concluding remarks.
Past research on cross-modal correspondences as they relate to tactile perception has largely been restricted to solid substances. We investigated the role of haptically explored liquid viscosity in crossmodal correspondences with visually presented luminance, saturation, roundedness, size, number and visual elevation, as well as pure-tone pitch and kiki-bouba-type letter strings. In Experiment 1, we presented two tactile and two visual or auditory stimuli simultaneously, and found significant inter-participant agreement (N = 32) when pairing viscosity with luminance, saturation, roundedness, size, pitch and letter string type. To assess whether these crossmodal correspondences were relative or absolute, another 32 participants were presented, in Experiment 2, with two tactile stimuli but only one visual/auditory stimulus per trial. In this second Experiment, we found that high viscosity was paired with low luminance, roundness, low saturation, and the bouba-type letter string, while low viscosity was paired with high pitch. However, the inverse
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ASL collection for viscosity and glycosylation studies. Collection of ASL from piglets was done in an enclosed humidified chamber (100% relative humidity, 25°C–30°C). Pigs were anesthetized with ketamine (20 mg/kg, intramuscularly) and xylazine (2 mg/kg, intramuscularly), and sedation was maintained with propofol (2 mg/kg, i.v.). The neck was dissected to expose the trachea. Tracheal secretion was stimu- lated with methacholine (2.5 mg/kg, i.v.). After approximately 5 min- utes, a small incision was made in the ventral tracheal wall, and sterile polyester-tipped applicators (Puritan Medical Products) were used to collect ASL as it traveled up the airway, thus minimizing contact with the tracheal wall. Applicators were inserted into microcentrifuge tubes, which were capped in the chamber to prevent evaporation. The tubes were briefly centrifuged to remove ASL from applicators, and the ASL was then pooled. We collected approximately 50 μl ASL from newborn CF piglets and up to approximately 100 μl ASL from non-CF piglets, which allowed for technical replicates and testing of interven- tions. Less volume from CF pigs is consistent with reduced volume secretion from CF submucosal glands (95). ASL was usually collected from non-CF and CF paired littermates studied on the same day and was used immediately after collection.
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1) Open water valve of PDA and start the laser and preheat it for 15 min. 2) The laser power is increased to 0.330 W after stabilising the laser to achieve moderate appropriateness of six beams of lights (e.g. blue, green and purple lights). 3) The maximum sampling time and maximum number of samples are set as 10 s and 10,000, respectively (sampling stops when sampling time reaches 10 s or the number of droplet samples exceeds 10,000) by the BSA software. 4) Spraying solution with certain viscosity is prepared, and the water pump is in- itiated until the pipeline flow becomes stable. 5) Sampling range and step length are set to generate the measuring meshing region. Subsequently, measurement begins, and the test interface of BSA software is shown in Figure 5. 6) The spraying solutions of different viscosities are prepared, and the parameters are reset. Repeat Steps 1 - 5. The test field is shown in Figure 6.
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Most researchers agree that the viscosity of the medium can also influence gas holdup. But in the literature, there are a lot of contradictions between investigators on the influence of viscosity on gas holdup. Philip et aL (1990) reported that in their experiments the gas holdup, at a given superficial gas velocity, increased with liquid viscosity. Deckwer (1992), Fields et aL (1984), Godbole et aL (1984), Haque et aL (1986), Heijnen and Van’t Riet (1984), Kawase et aL (1987), Kawase and Moo-Young (1990), Popovic and Robinson (1984), Schumpe and Deckwer (1982) and Shah et al. (1982) have stated an opposite effect. Deckwer (1992) and Heijnen and Van’t Riet (1984) explained that an increase in viscosity leads to the formation of large bubbles which reduce gas holdup. However, a high liquid viscosity may reduce bubble rise velocity (due to viscous drag) and this should enhance holdup; but they reported that the former seems to be predominant over the latter effect. Other investigators (Guy et aL, 1986; Onken and Weiland, 1980) found their gas holdup data to be independent of liquid viscosity. Furthermore, with CMC solutions in a bubble column Godbole et aL (1982) found, for increasing apparent liquid viscosity, the gas holdup to increase to a maximum and then decrease. From the above, it seems that the effect of viscosity on gas holdup in pneumatic reactors is still not clear and requires further study (Russell, 1989).
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Mesophase formation in industrial ebullated bed hydroprocessors is undesirable as it may cause operational problems such as fouling, reduced catalytic activity, and/or bed collapse. Hydroprocessing using a slurry bubble column configuration has been suggested as an alternative to minimize or eliminate mesophase formation based on reduced mass transfer limitations to catalytic sites. However, smaller diameter particles have been shown to agglomerate at relatively lower secondary liquid phase loadings in previous studies. The main objective of this work was to investigate the fluid dynamics of a slurry bubble column following the addition of a secondary immiscible liquid phase to provide relevant results for an industrial slurry bubble column hydroprocessor. Studies were carried out in a pilot-scale cold-flow slurry bubble column using nitrogen (gas), biodiesel (continuous liquid), glycerol (secondary liquid) and glass beads (solid). Axial pressure profiles and visual measurements were used to estimate local phase holdups and the overall agglomeration behaviour. This work focused on the impacts of four main parameters on particle agglomeration due to interparticle liquid bridging: secondary liquid loading, secondary liquid viscosity, particle diameter and sparger design.
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The following step was the code development after the basic idea of the project was formed. Firstly, the code was developed for a 3-dimensional lattice Boltzmann model based on the original Shan-Chen model and the improvements in the single-component multiphase ﬂow model reported by Yuan and Schaefer . The impaction of a liquid droplet on a dry ﬂat surface and a curved surface for a liquid-gas system with large density ratio was studied. In order to overcome the limitations of instability with a relaxation time τ less tan 1, another MATLAB code was developed on the base of a two-dimensional multi-relaxation-time interaction-potential-based lattice Botlzmann model to study speciﬁcally the dynamic behavior of liquid droplet on a curved sur- face for the liquid-gas system with large density ratio and low kinematic viscosity of the liquid phase. Then, a three-dimensional multi-relaxation time lattice Boltzmann model with an improved forcing scheme which can tolerate high density ratios and low viscosity is proposed to extend the application of the multiphase lattice Boltzmann model. At last, the developed code was applied to study the immiscible two-phase ﬂow in porous media, such as the ﬂow mechanisms with diﬀerent ﬂow regimes, the impact of the geometrical properties (volume fraction, solid phase contour length, solid phase connectivity) of the porous media on the relative permeability. Due to the limitation of computational capacity, the study on multiphase ﬂow in porous media was conducted in two dimensions.
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Liquid crystalline gel was prepared using Cetostearyl alcohol and tween 80 and double distilled water was added at approximately the same temperature followed by cooling slowly and mixing at 500 rpm stirrer. It was stored in wide mouth tightly closed container for evaluation. Five different combinations were selected for the preparation of Liquid crystalline gel varying in the composition of Cetostearyl alcohol and tween 80. Liquid crystalline gel was characterized on the basis of viscosity, encapsulation efficiency and in vitro release study. Viscosity is an important parameter for appropriate consistency of gel as it should be like an ointment. Therefore viscosity of the system was determined with the help of Brookfield viscometer (DV- E viscometer, Brookfield, USA) using spindle no 61 at
Experimental investigation has been conducted to study the effect of dispersed phase viscosity on drop mixing at different impeller speed. From the analysis, it can be seen that at viscous force does have an effect on the drop size distribution and mean drop size by affecting the rate of drop breakage. At high viscosity, drops are more stable and the possibility to deform is smaller. From the drop size distribution curves, low viscosity dispersed phase produced narrower distribution where the drops sizes are more uniform.
from the liquid fuels using an ionic liquid in the form of aromatics impurities located in the fuels and assist to achieve the focused separation of the extremely low sulfur gasoline. The principle concept of this simulation is to take a look at the impact of the usage of an ionic liquid for the elimination of sulfur impurities and to compare the experimental data with the simulation results. Since the ionic liquid is not available on the database of the ASPEN Plus (v8.8) so we need to rigorously define the structural aspects of the ionic liquid which include the volume and the surface area of the functional groups involved in the ionic liquid. The functional group numbers of the various functional groups of which ionic liquid constituents showed in Table 8 needs to be input into the ASPEN Plus due to the fact that ionic liquids are not present so every aspect needs to be specified in detail.
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Figure 2 shows that the pressure drop gratitude in the entrance region is larger than that in the developed region due to the extra pressure drop from the momentum change and the accumulated increment in wall shear in the entrance region. In the developed single-phase region, the xenon is subcooled and the pressure decreases linearly due to only the friction pressure drop. In the single-phase region, the liquid is seen as incompressible, so the liquid density, the velocity and viscosity is seen as constant in the constant mass flux resulting in constant pressure drop per meter. In the two-phase stage, the pressure drop gratitude is larger and larger and the slope is especially steep in the outlet of the pipe due to increasing of friction pressure drop and appears a new pressure drop, namely acceleration pressure drop. In the two-phase region, more bubbles are generated owing to flashing of xenon. The density of mixtures gradually declines while the velocity increasing. Through the momentum equation, the friction pressure drop is increasing and the acceleration pressure drop grows out of nothing and expends from small to large.
Bulk viscosity is a noticeable exception. Bulk viscosity of argon has been measured experimentally, 28–35 and its behav- ior can be qualitatively described by the results of a molecular dynamics simulation of a Lennard-Jones system. 36 However, when results of simulations with Lennard-Jones potential are rescaled in an attempt to describe experimental data liquid argon, bulk viscosity, contrary to other kinetic properties, ap- pears strongly underestimated (e.g., up to 50% in Ref. [27)].
During the 46 th and 51 st parabolic ight campaigns of the European Space Agency (ESA) samples were heated from room temperature to the foaming temperature of 650 or 700 C (depending on the alloy) over a total period of time of almost 200 s, and foamed during the 1g and 1.8g phases (1g z 9.8 m s 2 is the acceleration due to gravity) prior to a microgravity phase (0g) as shown in Fig. 1. The heating regime was synchronized so that foams almost lled the crucible during the rst 1.8g phase to avoid foam ageing and coarsening due to long holding times. During the subsequent microgravity periods (lasting 20–22 s) the liquid fraction became approximately homogeneous across the sample due to foam imbibition, i.e. liquid re-entering the foam. 5
Abstract - The purpose of this research was to develop and evaluate transformation type liquid crystalline transdermal drug delivery system of propranolol in a form of gel. The reverse micelle lamellar transformation liquid crystals were prepared from lecithin, isopropyl myristate and propranolol. Prepared liquid crystalline transdermal gel was evaluated for anisotropy, vesicular size, polydispersity index, encapsulation efficiency, viscosity and in vitro drug release study. Formulations were observed under polarized microscopy and found to have liquid crystals on the basis of the presence of birefringence. Vesicular size of the liquid crystals formulation was found from 784 to 968 nm and polydispersity index was found from 0.51 to 0.78 among all developed five formulations. Entrapment efficiency and viscosity was found from 64.54 to 83.24% and from 1090 to 1420 cp respectively in all five formulations. In vitro release of all the formulations was performed and data were treated for release mechanism. All the formulations exhibited controlled release property and formulation PLC2 followed Peppas-Korsmeyer release pattern. It was concluded that final formulation may offer controlled transdermal delivery of propranolol as compared conventional therapy.
using the parallel-plate viscometer, and they reported that oxygen contents of less than 0.8 at% do not drastically aﬀect the viscosity of the glassy phase, while the oxygen contents are more than 0.8 at%, viscosity of the supercooled liquid phase increased with increasing solute-oxygen. In the case of the Pd 40 Cu 30 Ni 10 P 20 alloy, surface oxidation was not
The purpose of this project is to design a flow process system to do the flow process measurement and control using PID control scheme. This chapter will briefly discuss the overview of this project. Measurement is the act or process of measuring something that we want to know about the system. In this project, flow rate of the water flow in the pipeline will be measured and controlled via PID control scheme. Nowadays, flow process play an important role in the industry area as the flow process measurement is the quantification of bulk fluid movement, either liquid or gas. Flow process measurement is very important in industry area because some application require the ability to conduct accurate flow measurement to such an extent that they influence product quality. Therefore, this process cannot be neglected. In this chapter, the background of the project, problem statement, project objective, work scope and report outline will be discussed.
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The initiation of phase 3 is determined by the zero-crossing of the negative acceleration peak (Fig.5B). In phase 3, the maximum expansion of the two pump organs has a definite phase shift (α). In the final phase, phase 4, the PP pushes the liquid posteriorly (toward the body) and the CP discharges the remaining fluid anteriorly (toward the food canal), causing the reversal of flow in the food canal. In our model, in the final phase the anterior pharyngeal valve is closed to prevent the reverse flow from the PP to the CP. The theoretical intake rate profile obtained by assuming that the anterior pharyngeal valve closes in phase 4 is well matched with the in vivo results. In this study, the anterior pharyngeal valve is considered to be open in phase 2 and phase 3, during which the PP draws liquid from the CP. On average, phase 2 and phase 3 accounted for about 62% of all phases in one pumping period. This percentage does not change significantly as the concentration of sucrose solution increases (ANOVA; F 2,12 =0.86, P=0.448).
In this work, the influence of Red Mud in the pyrolysis of general purpose polystyrene (GPPS) has been studied. The catalytic pyrolysis experiments were carried out using an unstirred semi-batch stainless steel 6.28 liter reactor under nitrogen atmosphere (air free) with Red Mud as a catalyst. The reaction effluents (oil and gases) were condensed in water-cooled condenser. The condensate was weighted to determine the total yield. Gas Chromatography-Mass Spectroscopy (GC-MS) analysis was used to characterize the condensed liquid organic compounds. According to the GC-MS results, styrene, benzene and its derivatives, toluene, naphthalene and a small amount of the other hydrocarbon compounds were identified in condensate liquid. Density, specific gravity, API gravity, kinematics and dynamic viscosity, flash point, fire point, cloud point and pour point of condensate were also measured. Under optimum reaction condition, the yield of pyrolysis reaction was above 90%. The air free reaction condition showed good catalytic pyrolysis of polystyrene with less than 1% coke formation and above 90% selectivity towards formation of aromatic compounds. The specifications of condensate, i.e. density, API gravity, viscosity and flash point observed showed that the liquid obtained can safely be classed as a kerosene. The specific gravity value was close to the specific gravity value of diesel.
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The local atomic ordering in a liquid A-B alloy is non-periodic, unlike crystals, as the solute atoms in the homogeneous solution can arrange in many ways by diffusion which contrasts with the pure metals A and B, in each of which the atoms can arrange only in a particular way. In the state of disorder in the atomic arrangements, some sort of short range atomic bonding (metallic, ionic, or covalent, or even secondary bonds, such as hydrogen bonding or Vander Waals forces as in the case of molecular crystals or liquids) can be assumed to exist between the nearest neighbours to present cohesive energy of solution. The cohesive energy of solution depends on the size difference of the atomic species and entirely to the size-dependent variations in the latent heats . The cohesive energy may be thought to be responsible for the enthalpic effect and the viscous nature of the liquid alloys. Viscosity of liquid metals/alloys is one of the technologically important transport properties, needed to develop and optimize metallurgical technologies. The analysis of the viscosity gives some insight into the alloying behaviour in the liquid alloys.
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