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Study of Parameters Affecting Size Distribution of Beads Produced from Electro-Spray of High Viscous Liquids

Study of Parameters Affecting Size Distribution of Beads Produced from Electro-Spray of High Viscous Liquids

Electro-Hydrodynamics (EHD) spray is an important process in many engineering operations such as ink-jet printing, spray drying and atomization (liquid jet in air), dispersion and emulsification (liquid jet in liquid). In this work the method of electro- spray was employed to form droplets from a high viscous sodium-alginate solution using constant DC voltage. The droplets were cured in calcium chloride solution to produce solid beads. The main objective was to extend the knowledge of EHD spray to high viscous and non-Newtonian liquids (1000-5000 mPa.s). However, the effects of electric field strength, nozzle diameter, flow rate and concentration of liquid were specifically investigated on the size of the beads. Among the parameters studied, voltage had a pronounced effect on the size of the beads as compared to the flow rate, the nozzle diameter and the concentration of alginate liquid. The size of beads was reduced to a minimum value by increasing the voltage in the range of 0-10 kV. However, within the middle part of this range, an unstable transition occurred from the dripping mode to the jet mode where the size distribution was wide. Increasing the height of fall of the droplets improved the sphericity of the beads, because of the increase of flight time for the droplets to relax before gelation.
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Laminar mixing of high-viscous fluids by a cylindrical chaotic mixer

Laminar mixing of high-viscous fluids by a cylindrical chaotic mixer

It is observed that the mixing index of ∆𝜔 = 10 𝑟𝑝𝑚 is greater than that of ∆𝜔 = 5 𝑟𝑝𝑚 until both mixing index profiles reach a steady state situation (at about t=81 s) when almost 90% of the free surface is covered by the dye. Furthermore, one can clearly see that the mixing time decreases with the increase of rotational speed amplitude, and required times to reach complete mixing for ∆𝜔 = 5 𝑎𝑛𝑑 10 𝑟𝑝𝑚 cases are 90 s and 72 s, respectively. According to Fig. 9 and using Eq. (2), the average mixing index for ∆𝜔 = 5 𝑎𝑛𝑑 10 𝑟𝑝𝑚 are obtained 45.1% and 56.6%, respectively. The reason of mixing enhancement in higher amplitude is due to a better condition of flow kinematic. Such flow kinematic can be attributed to the unsteady boundary conditions and acceleration of fluid particles which lead to a time-dependent perturbation in the mixer. Under this situation, fluid particles experience more area of the chaotic region with higher severity and consequently, folding and stretching of fluid elements occurs more rapidly compared to the situation in which the velocity variation of high- viscous fluid is not considerable. Therefore, the negative impact of low diffusivity of tracer into the base fluid is compensated by an increased interface which is a direct result of the successive folding and stretching phenomena occurring in the chaotic mixer. This point was also addressed in previous studies [6, 7, 16, 23-25]. In order to have a better understanding of the effect of the phenomena on mixing, the mechanism of blob tracer folding and stretching is schematically shown in Fig. 10. A tracer element is considered in an initial situation which has a low interface with the base fluid. As evident from this figure, due to successive folding and stretching phenomena, number pieces of tracer can be formed in the mixer and thus the interface between tracer and base fluid increases, causing a better condition for laminar mixing of high- viscous fluids.
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Compressed gas domestic aerosol valve design using high viscous product

Compressed gas domestic aerosol valve design using high viscous product

Ideally the new consumer aerosol valve design should be capable of performing in a similar way to current conventional (liquefied gas propellant) aerosol valves, and certainly have better spraying performance for a wide range of high viscous products. The spray performance can be best described by characteristics describing drop size, liquid flow rate, constancy of drop size and flow rate during can lifetime, and the capability of fully evacuating the can of liquid. The required performance should be achievable using existing commercially available cans and ideally using 12 bar cans which would be filled at 9 to 10bar. This Section presents a spray performance of the “Low Loss” valve with using olive oil and describes the results of this test. Also, it shows a comparison of olive oil spray performance of “low loss” valve and a conventional domestic valve which was provided from a major company in which because of the strict confidentiality imposed the authors cannot mention its name. Furthermore, this Section provides some qualitative spray performance with using some different high viscous products to show the capability of this new design valve. The sprays were characterised using the laser instrument. The downstream distance between the atomiser insert and the laser beam was kept at 15cm. This downstream distance was selected as being the furthest downstream that could be used without the risk of the spray impingement on the lens. All images were also captured using a digital still camera which provided qualitative information and also data on cone angle.
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Adaptation of High Viscous Dampers (HVD) for Essential Decreasing of In-Structure Floor Response Spectra

Adaptation of High Viscous Dampers (HVD) for Essential Decreasing of In-Structure Floor Response Spectra

The proposed method of High Viscous Damper (HVD-approach) is also oriented on increasing of total energy dissipation of NPP buildings and structures. From this point of view the degree of dissipation increment determines the efficiency of reducing of inertial loads and response motions excited by the external dynamic loads. The main idea of HVD-approach is to use general systems or subsystems that can independently move about each other under external loads. Then such their property can be used for efficient energy dissipation by VD dampers connection of system to system or subsystems.
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A 2-D Time-Dependent Ripple Prediction Model for Wave Dominated Flows

A 2-D Time-Dependent Ripple Prediction Model for Wave Dominated Flows

biofilm’s hydrodynamic stays mostly static in the absence of shear. The viscous model pre- dicts that the biofilm essentially stops moving after the imposed shear ceases. In contrast, the viscoelastic model predicts that the biofilm gradually recoils back partially toward the original position. The elastic stress tries to contract the fluid along its principal stress di- rection. The incompressibility condition, in turn, causes the fluid to expand in the direction perpendicular to the contraction. This induces a flow throughout the biofilm, which in turn induces the viscous stress. Fig.4.12 illustrates this mechanism. It can be seen that the lo- cation of high viscous stress coincides with the location of high elastic stress, and that the viscous stress tends to have its principal direction perpendicular to that of the elastic stress. The net elastic force, net viscous force, and net MCH force are strongest near the biofilm-solution interface, as illustrated in Fig.4.11. This is surprising at first, since the stress is distributed throughout the biofilm, so intuition tells us that their corresponding forces should act throughout the biofilm body. After a moment of reflection, one realizes that these forces are indeed strong inside the biomass. However, they are canceled out by an equally strong force in the opposite direction, leaving the net forces to be small inside the biomass. Near the biofilm interface, these opposing forces have unequal strength, since the elastic stress and bacterial viscous stress exist only in the biomass, thus we observe a high net force there.
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A  New Method for Essential Reduction of Seismic and External Loads on NPP's  Structures, Systems and Components (K279)

A New Method for Essential Reduction of Seismic and External Loads on NPP's Structures, Systems and Components (K279)

The proposed idea consists of using of special aseismic devises, namely High-Viscous Dampers (HVD), not for fixing each system, component, piping inside containment but for initial decreasing of seismic input and external event hazard for all elements of reactor building. This approach could bring essential cost benefit in comparison with rigorous efforts for providing necessary dynamic capacity of each safety related SSC.

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Formulation and evaluation sustained release mucoadhesive gastroretentive pantoprazole sodium sesquihydrate tablets for anti–ulcer

Formulation and evaluation sustained release mucoadhesive gastroretentive pantoprazole sodium sesquihydrate tablets for anti–ulcer

The percentage drug release for Carbopol was less than HPMC tablets of pantoprazole sodium sesquihydrate may be due to its high viscous and mucoadhesive nature. The per[r]

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Effects of viscous dissipation on miscible thermo viscous fingering instability in porous media

Effects of viscous dissipation on miscible thermo viscous fingering instability in porous media

The thermo-viscous fingering instability associated with miscible displacement through a porous medium is studied numerically, motivated by applications in upstream oil industries especially enhanced oil recovery (EOR) via wells using hot water flooding and steam flooding. The main innovative aspect of this study is the inclusion of the effects of viscous dissipation on thermal viscous fingering instability. An Arrhenius equation of state is employed for describing the dependency of viscosity on temperature. The normalized conservation equations are solved with the finite element computational fluid dynamics code, COMSOL (Version 5) in which glycerol is considered as the solute and water as the solvent and the two-phase Darcy model employed (which couples the study Darcy flow equation with the time-dependent convection-diffusion equation for the concentration). The progress of finger patterns is studied using concentration and temperature contours, transversely averaged profiles, mixing length and sweep efficiency. The sweep efficiency is a property widely used in industry to characterize how effective is displacement and it can be defined as the ratio of the volume of displaced fluid to the total volume of available fluid in a porous medium in the displacement process. The effects of Lewis number, Brinkman number and thermal lag coefficient on this instability are examined in detail. The results indicate that increasing viscous dissipation generates significant enhancement in the temperature and a marked reduction in viscosity especially in the displaced fluid (high viscous phase). Therefore, the mobility ratio is reduced, and the flow becomes more stable in the presence of viscous dissipation.
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Thermal Analysis Of Scraped Surface Heat Exchanger Used In Food Industries

Thermal Analysis Of Scraped Surface Heat Exchanger Used In Food Industries

In this paper we describes problem of shell and tube heat exchanger use for high viscous fluid and study of thermal analysis of scraped heat exchanger by using high viscous fluid which is used in food industries, chemical, or pharmaceutical industries for several thermal applications such as freezing, sterilization, cooling and gelatinization. Study of effect of different parameter like mass flow rate, blade design, on a heat transfer performance and power consumption of a scraped surface heat exchanger. Experimental model and CFD analysis is used for thermal analysis. Milk is used working fluid and water for cooling medium. Solid work used for 3D modeling. CFD analysis result shows that increasing cooling of the milk by using a small scraper design than full blade design. CFD analysis result shows that pressure drop on milk side also reduce. Heat transfer is increase due to increase in a temperature difference for small scraper design than full blade design. Due reduce load on a shaft for small scraper design than full blade design, power consumption reduce for small scraper design than full blade design. Due to decrease contact of fluid with scraper in small scraper design, shear stress on fluid is reduced and Due to reduce stress on a product quality is improve.
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Slip flow of an optically thin radiating non-Gray couple stress fluid past a stretching sheet

Slip flow of an optically thin radiating non-Gray couple stress fluid past a stretching sheet

et al. [7], Siddappa and Abel [8], Andersson [9], Kumaran and Ramanaiah [10], Wang [11] and Cortell [12]). Flow of elastico-viscous fluid induced by a stretching sheet with slip has been presented by Ariel et al. [13]. Akyildiz et al. [14] have discussed the diffusion of chemically reactive species in a porous medium over a stretching sheet. Wang [15] have made an analysis of viscous flow due to a stretching sheet with surface slip and suction. Fang et al. [16-17] have obtained the exact solution of an MHD slip flow over a stretching sheet. The thermal boundary layers over a shrinking sheet have been analytically studied by Fang and Zhang [18]. The heat transfer characteristics in a visco-elastic boundary layer flow over a stretching sheet have been analyzed by Arnold el al.[19]. Shantha et al. [20] have presented the free convection flow of a conducting couple stress fluid in a porous medium. Srinivasacharya and Kaladhar [21] have conducted a study of a mixed convection flow of couple stress fluid in a non-darcy porous medium with Soret and Dufour effects. The second-order slip flow and heat transfer over a stretching sheet with non-linear Navier boundary condition have been numerically investigated by Nandeppanavar et al.[22]. Singh and Makinde [23] have studied an MHD slip flow of viscous fluid over an isothermal reactive stretching sheet. Hayat et al. [24] have presented the stagnation-point flow of couple stress fluid with melting heat transfer. Turkyilmazoglu [25] has obtained an exact solution for two-dimensional laminar flow over a continuously stretching or shrinking sheet in an electrically conducting quiescent couple stress fluid. The MHD flow and heat transfer of an exponential stretching sheet in a Boussinesq-Stokes suspension have been examined by Siddheshwar et al. [26]. Salema et al. [27] have studied the hydromagnetic flow of Cu- water nanofluid past a moving wedge with viscous dissipation. Zhu et al. [28] have presented the second-order slip MHD flow and heat transfer of nanofluids with thermal radiation and chemical reaction. Sheikholeslami et al. [29] have investigated the magnetic nanofluid forced convective heat transfer with variable magnetic field using two-phase model. The effect of non-uniform magnetic field on forced convection heat transfer of Fe 3 O 4 - water
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Development and usability of a new subcutaneous auto-injector device to administer hydroxyprogesterone caproate to reduce the risk of recurrent preterm birth

Development and usability of a new subcutaneous auto-injector device to administer hydroxyprogesterone caproate to reduce the risk of recurrent preterm birth

An auto-injector is a device that completely or partially replaces the activities involved with parenteral drug adminis- tration with a conventional syringe and needle. Such devices are increasingly being developed for use in the clinical set- ting or home environment for treatment of acute and chronic conditions. Potential advantages that may be expected with an auto-injector include reduction in patient anxiety from “needle phobia” since the patient does not see the needle; a reduction in needlestick injuries resulting from a hidden needle with a shielded needle tip; reduction of errors in drawing up the dose consistently; prevention of accidental drug contamination while drawing up the viscous drug or changing the needle; convenience and efficiency to the health care provider; and performing a standardized administration in which the needle is inserted to a specific depth, ensuring that the full dose is delivered every time. 19–21
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Formation and decay of capillary turbulence on the charged surface of liquid hydrogen

Formation and decay of capillary turbulence on the charged surface of liquid hydrogen

viscous damping of the waves causes a qualitative change in the character of relaxation of nonlinear surface waves. We may infer that the shape of the low frequency (power-like) part of the spectrum is stabilized by a fast redis- tribution of energy between waves within the inertial range of frequencies. This is why the observed spectrum remains close to quasiequilibrium over relatively long times following the start of the decay.

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Velocity Resolved - Scalar Modeled Simulations of High Schmidt Number Turbulent Transport

Velocity Resolved - Scalar Modeled Simulations of High Schmidt Number Turbulent Transport

spectrum. For demonstration purposes, we suppose that the low-pass filter cutoff is placed at the boundary of regions E and F. The resulting transfer spectrum after filtering, shown in Fig. 2.6(b), is obtained by summing the scalar mode contributions from wavenumber ranges A through E. The excellent agreement between the full and filtered spectra at low and intermediate wavenumbers yet again emphasizes the minimal influence of high wavenumber modes. However, we note that there is no longer a cancellation of the E+ spike from an F− spike, since the F modes have been filtered out. The E+ spike, if left unchecked, can lead to a pile-up of scalar energy at the large wavenumbers. This could have an indirect effect on the scalar transfer, especially when using scalar energy conserving transport schemes. The high wavenumber modes involved in this pile-up cannot be represented on a given grid and are incorrectly represented at lower wavenumbers. Aliasing of this sort contaminates the energy content of the resolved Fourier modes in the simulation. These observations lead to the realization that the primary role of a subfilter model, when used with filtering in the viscous- convective subrange, is primarily to facilitate the dissipation of the equivalent of an E+ spike close to the cutoff wavenumber. Interaction of the subfilter model with low wavenumber scalar modes, for facilitating scalar transfer directly at the large length scales, is not essential for Sc 1.
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Shrinking of Solid state Nanopores by Direct Thermal Heating

Shrinking of Solid state Nanopores by Direct Thermal Heating

having an initial diameter of 250 nm were reduced to 3 nm at 1150°C as shown in Figure 2. The nanopores were imaged with TEM after each temperature proces- sing step to characterize the process. After loading the dyes into the furnace, the temperature was allowed to stabilize for 30 s before counting the actual processing time. After the thermal process, the dyes were unloaded from furnace and cooled down to room temperature. When the dyes were processed at temperatures below 1000°C, it was observed that there was very little or no change in the diameter of the nanopore. This can be explained by the fact that at low temperature (<1000°C), the oxide layer would not be relaxed to an extent that it would start changing pore morphology. When the nano- pores were processed at a higher temperature (>1250° C), the oxide membranes either broke due to very high thermal stress or the shrinking process was too fast to control. This was especially so for pores smaller than 20 nm diameter [24]. As an example, a nanopore with initial diameter of ~270 nm, processed at 1250°C, is shown in Figure 3. The TEM images of the nanopore
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Self-Aggregation of Cryptococcus neoformans Capsular Glucuronoxylomannan Is Dependent on Divalent Cations

Self-Aggregation of Cryptococcus neoformans Capsular Glucuronoxylomannan Is Dependent on Divalent Cations

Extracellular GXM aggregates to form a highly viscous film. After the complete removal of cells and debris by centrifuga- tion, C. neoformans supernatants (at initial volumes of 800 ml) were concentrated in ultrafiltration cells. Final volumes of 40 ml were achieved, and the upper fluid phase was removed. Sticky, translucent, 2- to 4-mm-thick films were obtained on the surfaces of the ultrafiltration discs (see Movie S1 in the supplemental material). Concentration rates of supernatants from different cultures varied, but films were always formed after 1 to 3 h of ultrafiltration. The viscous films were then collected with a cell scrapper and stored at room temperature for further analysis. The final volume of the viscous film prep- aration obtained from 800-ml cultures ranged from 10 to 15 ml. Interestingly, film formation was also observed when superna- tant fractions that were passed through the 100-kDa mem- brane were concentrated using 10-kDa filtering discs (data not shown). Serotype A C. neoformans strains and Cryptococcus gattii isolates (serotypes B and C) were used under the same conditions, with similar results being obtained (data not shown).
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On the effective properties of nematic polymer nano-composites

On the effective properties of nematic polymer nano-composites

high nematic concentrations (Constantin et al. (2004)). Nonetheless, decades of mesoscopic theory are based on closing the equations at the second-moment tensor level of resolution of f (Beris and Edwards (1994), de Gennes and Prost (1993), Larson (1999)). In particular we (Forest and Wang (2003), Forest et al. (2003)) have introduced moment-closure benchmarks based on faithful reproduction of the PDF attractors & phase transitions versus concentration (volume fraction) and shear rate. Using special properties of the Doi theory (Forest et al. (2003), Forest et al. (2004 c)), we can easily extend these formulas to any linear planar flow in the weak flow rate limit. In all these cases we can now give explicit formulas for P and Σ e
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Experimental investigation of pressure disturbances influence on a parallel flow of viscous immiscible liquids in a T-shaped microchannel

Experimental investigation of pressure disturbances influence on a parallel flow of viscous immiscible liquids in a T-shaped microchannel

Pressure disturbances with high amplitude and low frequency influence on the parallel flow of viscous immiscible liquids in a T-shaped microchannel was studied experimentally. The transition to the slug flow regime was observed. A non-dimensional parameter was introduced to determine the boundary between slug and parallel flow and to construct flow pattern map. Slug lengths and velocity were measured for all the cases studied. It was found that pressure disturbances with sinusoidal signal shape applied to both liquids lead to very narrow slug length and velocity distribution. The last can be useful in design and optimization of microdevices operating with immiscible liquids.
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Effects of Magnetic Field and Variation of Viscosity and Thermal Conductivity on Separation of a Binary Fluid Mixture over a Continuously Moving Surface

Effects of Magnetic Field and Variation of Viscosity and Thermal Conductivity on Separation of a Binary Fluid Mixture over a Continuously Moving Surface

Professor, Department of Mathematics, Dibrugarh University, Dibrugarh-786004, Assam, India 1 Research Scholar, Department of Mathematics, Dibrugarh University, Dibrugarh-786004, Assam, India 2 Abstract: The effects of viscous dissipation, Joule heating and chemical reaction on demixing of a binary mixture of incompressible viscous electrically and thermally conducting fluids in two dimensional steady boundary layer flow with temperature dependent viscosity and thermal conductivity due to a continuously moving surface under the influence of weak uniform transverse magnetic field is investigated. The momentum , energy and concentration equations are reduced to non-linear coupled ordinary differential equations by similarity transformations and are solved numerically by using MATLAB’s built in solver bvp4c. These numerical results are exhibited graphically from which it has been found that the effects of various parameters are to separate the components of the binary mixture by collecting the lighter and rarer component near the surface of the plate and throwing the heavier one away from it. The effects of various parameters on the local skin friction, the Nusselt number and the Sherwood number have been shown in tabular form.
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To What Extent Could Methanol, Toluene and Gas Condensate Effect on Heavy Crude Oil Viscosity,  Sheikhan Oil Field, Kurdistan, Iraq

To What Extent Could Methanol, Toluene and Gas Condensate Effect on Heavy Crude Oil Viscosity, Sheikhan Oil Field, Kurdistan, Iraq

The method is widely utilized to reduce the viscosity of heavy crude oil. The main principle of this technique lies in the fact that the viscosity factor decreases by increasing heat. The applied heat making the crude oil easier to be pumped through pipeline from the produced well to the production facilities. Therefore, it is necessary to maintain the temperature high at which the crude oil is extracted by isolated pipe [16].

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Numerical Solutions of 2-D Incompressible Driven Cavity Flow with Wavy Bottom Surface

Numerical Solutions of 2-D Incompressible Driven Cavity Flow with Wavy Bottom Surface

A two dimensional lid driven cavity of height and length L with wavy bottom surface is considered, as shown in Fig. 1. The shape of the bottom wavy surface profile is assumed to mock following the pattern y = A ( 1 − cos( 2 λπ x )) , where A is the dimensionless amplitudeof the wavy surface and λ is the number of undulations. The upper wall of the cavity is allowed to move in its own plane at a constant speed unity and the other walls have no-slip condition. In general, the cavity fluid is assumed to be Newtonian and incompressible, unsteady and laminar flow. It is further assumed that viscous dissipation is neglected in this study. With abovementioned assumptions, the governing equations for conservations of mass and momentum can be written as
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