Papers by Keyword: Viscosity

Abstract: The influence of fibrous and solid granulated fillers on the rheological and surface properties of the polymer compositions on the basis of polyvinyl alcohol and Na-carboxymethyl cellulose is demonstrated. The polymer complexes with Na-carboxymethyl cellulose and sodium tetraborate additions and the compositions filled with polypropylene, polyethylene terephthalate and quartz sand are obtained and comparative assessment of the properties of studied polymer composites have been made. Polymer compositions with quartz sand, synthetic and plant fibrous fillers increase the effective viscosity, elasticity modulus and decrease the adhesive strength of all compositions based well on carboxymethyl cellulose and polyvinyl alcohol. The sodium tetraborate introduction promotes the formation of the composites surface with the lesser adhesive strength.

Abstract: The diffusion coefficients of the basic diagnostic gases were determined by optical recording of the bubble dissolving dynamics in degassed insulating liquid. It is necessary to understand the diffusion of diagnostic gases in insulating liquids for obtaining high-quality diagnostic conclusions obtained during the analysis of high voltage electrical equipment with paper-oil insulation using gas methods.

Abstract: Quench heat treatment consists of rapid cooling of steel alloys after austenetization by subjecting them to cooling in a suitable cooling medium. At the heart of quench treatment is the transient heat transfer that occurs between the metal surface and the quenchant at their interface. This governs the quality of the component as it influences phase transformation, residual quench stresses and mechanical properties developed. In the present research work, spatially dependent transient heat flux in the axial direction was estimated using cooling curve analyses coupled with inverse heat conduction technique. A standard Inconel 600 probe instrumented with multiple thermocouples and heated to 865°C was quenched in distilled water (DW) and DW based multi walled carbon nanotubes (MWCNT) quench media. For evaluating the cooling performance, nanoquenchants with concentrations of 0.01, 0.1 and 1.0g/lt. were prepared. The cooling rate curve calculated from the measured temperature at the geometric center of the probe and the estimation of spatially dependent heat fluxes showed that the heat extraction during quenching with MWCNT nanoquenchant (0.1g/lt.) was higher than the other quenchants. The measured values of thermal conductivity and viscosities of quenchants did not show any significant variation.

Abstract: One of the challenges which Laser Sintering faces is the Rapid Manufacturing of plastic parts with good consistent quality. This is due to the fact that plastic powder properties deteriorate during the long periods of time through the LS building and cooling cycles. This paper presents an experimental study of the deterioration or ageing of PA12 powder properties in the LS process. The influences of different grades of recycled PA12 powders are investigated. The main aim of this research is to develop a methodology of controlling the input material properties that will ensure consistent and good quality of the fabricated parts. From the experiment it was found that PA12 powder with high melt flow rate, low melting temperature, low glass transition temperature and low degree of crystallization temperature could improve the sintering process to produce a good Laser Sintering (LS) parts with lower shrinkage rate.

Abstract: Cashew nut shell oil (CNSO) is potential alternative fuel for diesel engine. Its drawback is incomplete combustion and low brake thermal efficiency (BTE) due to high viscosity. To overcome this problem the CNSO was blended with diethyl ether (DEE) which is less viscous and burns easily. The influence of blends on CO, NOx and smoke emission is investigated by emission tests. The fuel containing 20% CNSO and 80% diesel fuel (B20), 95% B20 and 5% DEE by volume (B20D5), 90% B20 and 10%DEE by volume (B20D10) 85% and B20 and 15% DEE by volume (B20D15) are tested. Initially the experiment was conducted with different blends of CNSO-diesel blends like 10%, 20%, & 30% by volume basis in a diesel engine.The aim for the research of alternative fuel is to replace the sufficient amount of diesel fuel without affecting the existing engine performances. Increasing CNSO diesel blends performances reduces marginally. B10 shows more closer performances to diesel fuel, but replacement of 10% only diesel is not much. Using B30 and higher blends gives poor result. Hence it was decided to be B20. In the second stage B20 as a base fuel and it is blended with DEE 5%, 10% & 15% by volume basis at different load conditions. The result shows that B20D15 has BTE 26.50% which is very close to the base diesel fuel. The B20D15 emits 1200 PPM of NOx while diesel emits 1195 PPM but B20 emits 1450 PPM of Nox. Carbon monoxide (CO) emission also reduces for different blends of DEE. The smoke emission is 3.96, 3.38, 3.15 FSN of B20, B20 D15 and diesel respectively.

Abstract: Insulation is one of the most important parts in the power transformer. Palm oil impregnated paper is investigated to replace the mineral oil impregnated paper due to the high viscosity of palm oil compared to the viscosity of the mineral oil. This paper discussed on ultrasonic radiation technique that was used to reduce the viscosity of the vegetable oil (palm oil) for transformer insulation application. The ultrasonic equipment produces 500W heating power, 240W ultrasonic power at a fixed frequency of 40 kHz. Ultrasonic radiation was applied on oil samples at 30 °C, 50 °C and 75 °C by using the sonicator water bath for several periods of time. The results show up to 42.6 % reduction from the original viscosity of palm oil and proved to have a long term effect on the viscosity of palm oil. The cavitation bubbles that occur in the sample during radiation is one of the mechanism in viscosity reduction.

Abstract: Much published literature on the way in which phase morphology and filler distribution affect blend properties is contractor or confusing The blending of two or more polymers by physical or chemical means may improve a variety of physical and chemical properties of the constituent polymers. The effect of different modes of filler addition on dispersion and viscosity of Epoxidisd Natural Rubber (ENR) and cis 1,4 –polybutadiene rubber (BR) has been studied. Experiments were carried out to elucidate the relationship and to determine whether the use of special mixing technique and compatabilizers might have a beneficial effect on Epoxidised Natural Rubber: Butadiene Rubber (ENR:BR) blend properties. The findings indicated blending times for combining Silica, BR and ENR was rather difficult even a close viscosity of each rubber was applied. Results indicated a high degree of compatibility with fine structured blends being quickly and easily produced with compound containing compatibilizer than compound with any. Hence, a high viscosity and poor filler dispersion was obtained with all mixing techniques applied except with the one with the coupling agent.

Abstract: Coal is currently the most widely used and most abundant fossil fuel in the world. It is primarily used for generating electricity at power plants. However, due to problems of pollution and energy consumption, importance has been placed on the development of clean coal technology. Coal-water slurry (CWS), consisting of fine coal and water mixture, is a liquid fuel used to replace heavy fuel oil for boilers and entrained flow gasifiers. Since CWS is a liquid with high viscosity and regular atomizing burners are designed for the use of fossil fuels with low viscosity, it is necessary to design high efficiency atomizing burners specific for CWS. As viscosity is a key factor for atomization characteristics, we used silicon oils of different viscosity as the testing liquids, to study the effect of different atomization parameters on the atomization characteristics. Our results show that, when the gas to liquid ratio (GLR) is high, the existing particle velocity at the central axis is lower than low GLR condition; likewise, the velocity at radial positions is higher of the high-viscosity case. The velocity also increases as the radial distance further increases away from the axis. And decrease as the GLR increases. On the other hand, the distribution of the velocities does not change after the radial distance reaches a certain limit. This limit decreases as the axial length increases. Increasing viscosity increases the inertial force of the liquid fluid, so the momentum of the atomization gas needs to be increased for it to generate enough shear stress on the fluid and to enhance the atomization characteristics.

Abstract: The resin transfer molding (RTM) offers great conditions for mass production of fiber reinforced plastics. In this process, preformed fiber textiles are infiltrated with matrix material (for example: epoxy resin). During the infiltration, the matrix material starts a curing process until the complete consolidation. After the de-molding and a short post-processing step, the final part is ready to use. To reduce the cycle time for the RTM manufacturing, it is necessary to model and predict the flow behavior of the matrix material in a realistic way. An important parameter is the preform permeability, which characterizes the flow resistance of fibers against the flowing matrix material.In this study a new measurement setup is presented, which is able to determine the permeability directly during the manufacturing process, with integrated pressure and temperature sensors. This approach has many advantages against conventional measurement setups, that try to recreate the RTM process with a simple replication. With these replicas, it is only possible to simulate low flow velocities and pressures. Dynamic effects that occur at higher velocities cannot be regarded. Furthermore, the new setup has the advantage that measurement artifacts, like capillarity, have a lower impact. In addition to that, the infiltration can be done with a constant viscosity test fluid as well as with reactive matrix material. Thus, it allows further determination of the time depending viscosity.

Abstract: Density and viscosity are two major rheological properties that determine the performance of an isopropyl laurate (IPL) ester based drilling fluid. In this study, the effect of barite particle size on the IPL drilling fluid system settling behaviour was investigated using five particle sizes namely-32, 32-45, 45-75, +75μm and the unsieved barite. Stokes’ law of separation theory was employed in the analysis. It was found that smaller barite particle sizes (<75μm) enhances the settling resistance. An ideal barite particle size of-32μm was chosen and used in the subsequent formulations to obtain optimum rheological properties by varying the amount of viscosifier used at 4.0, 10.0 and 20.0g marked as sample (a), (b) and (c). These samples were analysed for their rheology by using the conventional Fann viscometer calibrated using Bingham model. The results showed that sample (b) exhibited the most promising performance based on the plastic viscosity, yield point and gel strength rheological analyses. Moreover, IPL drilling fluid sample (b) showed improve particle suspension ability for more than 78 hours when compared to IPL drilling fluid system prepared using unsieved barite particles. The results suggested that palm oil based isopropyl laurate ester has the potential to be used as based fluid in the ester based drilling fluid system.