Papers by Keyword: Viscosity

Abstract: The bulk density of the injection grout is an important factor, as its additional weight could cause damage to hardened decorative plasters. This can be particularly noticeable on larger surfaces. This study used five types of lightweight filler as a density-reducing component in hydrated lime-based grouts. The commonly used limestone filler was completely replaced by an expanded or granulated filler with a loose bulk density of up to 900 kg m⁻³; the rheological properties of the prepared grouts were then studied using a hybrid rheometer. The lime grouts were non-Newtonian, shear-thickening fluids exhibiting rheopectic behaviour (i.e. they stiffened over time). The type of filler dramatically affected the flowability of the grouts. The yield stress and plastic viscosity of the grouts decreased when lightweight fillers were used. As the filler density decreased, the grouts became expectantly less stiff. However, they showed a higher proportion of elastic behaviour than viscous behaviour, indicating that they have a strong microstructure that is resistant to external influences. There was no increase in loss factor values at higher frequencies, indicating that there was no separation of the liquid from the grout structure. From a rheological point of view, expanded glass appeared to be the most effective of the lightweight fillers used.

Abstract: The increasing demand for sustainable energy solutions has intensified research into biodiesel production, which relies on chemical catalysts that have an environmental impact. This study investigates the alternative methods of biodiesel production by utilizing agricultural waste, specifically rice husk, coconut husk, and chicken manure as a catalyst for biodiesel production. Laboratory experiments were conducted to extract metal oxide from agricultural waste to be used as a catalyst in the transesterification process. The obtained ash was characterized, and it was revealed that rice husk ash contained 98% SiO₂, coconut husk ash had 72.62% of K₂O, and chicken manure ash had 46.56% CaO, with higher metal oxide compositions in each material. The transesterification reaction was conducted by varying alcohol to oil ratio from 3:1, 6:1, 9:1, and 12:1, temperature (40-80°C), catalyst concentration (1.5-4.5%wt), and reaction time (20-120min) to assess catalyst efficiency. Pure CaO was used as a control catalyst for comparison. Characterization of the produced biodiesel from all catalysts was conducted and compared to ASTM D6751 standards. The results for acid value, moisture content, density, viscosity, free fatty acid, flash point, pour point, and cloud point were analyzed and found to comply with ASTM D6751 standards. On quantity determination of produced biodiesel, the most effective catalyst was chicken manure ash with a yield of 80% and the least effective catalyst was rice husk ash with 68% yield. Using agricultural waste reduces up to 40% production cost.

Abstract: This study investigates the rheological and optical properties of sustainable palm oil-based offset printing inks, comparing four formulations with varying pigment concentrations (Palm Ink-15, Palm Ink-16, Palm Ink-17, and Palm Ink-18) against a conventional ink sample. Through rheology testing, we analyzed viscosity, yield value, and shortness to understand ink flow characteristics. Optical density measurements and colorimetric assessments in CIE L*a*b* coordinates were conducted to evaluate ink performance across different film thicknesses. The results indicate that palm-based inks exhibit a superior balance between viscosity and yield value, allowing for effective ink transfer and enhanced color saturation. Palm Ink-17, in particular, demonstrated the most rapid color intensity buildup with increased thickness, making it optimal for applications requiring rich, saturated blue tones. These findings suggest that palm oil-based inks are not only environmentally friendly but also exhibit performance characteristics suitable for high-quality offset printing applications.

Abstract: Lubricants are substances that minimize wear and friction for optimal performance and lower the likelihood of malfunctions. Over 95% of lubricants used today are made of non-renewable petroleum, which is being depleted and emitting emissions that are bad for the environment and people's health. The greatest substitutes are biolubricants, whose primary sources include edible and inedible oils that are generated from lipids and carbohydrates found in various animals, plants, and microbe sources, with the exception of Algae. An eco-friendly and sustainable resource for green lubricants, microalgae oil is vital to the lubricant business. Microalgae are photoautotrophs, meaning they grow quickly and can be grown multiple times a year with less energy needed. Because microalgae do not require agricultural land or climatic conditions to develop, they may also be produced in wastewater and saltwater. As a result, their production costs are also lower. Microalgae has exceptional chemical compositions, including significant levels of lipids, hydrocarbons, polysaccharides, and gelling properties. Microalgae are suitable for lubrication because they contain high amounts of saturated, mono-unsaturated, and polyunsaturated fatty acids, which give algae their good tribological, physiochemical, and rheological qualities and minimize friction. Molecular weight, viscosity, oxidation stability, thickening behaviors, friction coefficient, antiwear, antiseizure, thermal stability & characteristics, crystallinity, and rheology of polysaccharides as sustainable green lubricant are all covered in this review study about the lubricating properties of microalgae oil.

Abstract: An experimental study was performed to evaluate the effect of iron, ferronickel, and stainless steel 304L (85-92wt%) powder injection molding (PIM) on the compressive strength and rheological behavior of polyamide (PA6/M) composite. The feedstock, prepared at 260°C, was extruded into a composite film. The effect of particle shapes and size distribution was investigated using Scanning Electron Microscopy (SEM) to evaluate the relative viscosity value of the PA6/M feedstock. The results showed that the compressive strength and rheological behavior were determined by the blend composition. The increase in compressive strength was due to the higher strength of the metal powders compared to PA6, along with heightened surface energy leading to mechanical interlocking. Furthermore, the metal powders generated frictional resistance resulting in an increase in viscosity, making the feedstock unstable and decreasing the rheological properties. According to the compression and rheology test, all variations with an 85wt% metal powder exceeded the minimum specifications for frangible projectile materials. The highest compressive strength of PA6/85Fe was 144.503 MPa and the lowest viscosity of PA6/85FeNi was 352.85 Pa.s.

Abstract: The FeSi system is a compound forming alloy which exhibits the interesting behavior with respect to the composition. In present work, the thermophysical properties of FeSimelts at 1873 K have been explored on using four-parameter model which is based on Maclaurin infinite series. The analytical expressions for various thermodynamic and microscopic functions have been deduced using the standard thermodynamic relations. The model parameters are estimated using experimental data of activity coefficients and excess free energy of mixing for FeSi melts at 1873 K. For theoretical calculations of the thermophysical properties of FeSi liquid alloys at 1873 K, the same values of the model parameters are used in order to maintain the consistency. The composition dependence of theoretical data for Gibbs free energy of mixing and thermodynamic activities are in excellent agreement with the corresponding experimental data at 1873 K. On using the temperature dependence of model parameters, the enthalpy of mixing and entropy of mixing of FeSi molten alloys at 1873 K arecomputed. There is a well agreement between the theory and experiment. The theoretical values of concentration-concentration structural factor, known as concentration fluctuations in the long wavelength limit agree well with experimental data for FeSi system in molten state at 1873 K. The microscopic function such as short-range order parameter has also been computed as a function of concentration of FeSi melts at 1873 K. Again, the surface properties such as surface concentration and surface tension of FeSi molten alloys at the temperatures at 1823 K and 1873 Kare analyzed by Butler modelin the framework of four-parameter model. The theoretical values are compared with the data available in the literature at 1823 K which show well agreement. Again, the excess free energy of mixing, heat of mixing, concentration fluctuations and short-range order parameter are explored at 1823 K, 1873 K, 1923 K and 2073 K. Further, the transport properties like diffusivity ratio and viscosity of FeSi liquid alloys at 1823 K, 1873 K, 1923 K and 2073 Kare computed. For this, a simple statisticalmechanical modeli.eMoelwyn-Hughes model isemployed in the framework of four-parameter model. The theoretical data exhibit the qualitative agreement with the data available in the literature. The present study reveals that FeSi melt is an ordered system in the temperature range 1823-2073 K. The model parameters are temperature dependent. The concentration dependence of short-range order parameter and diffusivity ratio indicates that there is a likelihood of the existence of complex in FeSi liquid alloys. Keywords:Free energy of mixing; heat of mixing; concentration fluctuations; short-range order parameter, surface tension; viscosity

Abstract: In this article, the effect of TiC nanopowder particles on the wear resistance of low-alloy steel 35XGCL (analog is JIS G 5111) is mathematically modeled. First of all, the composition for liquefaction in an electric arc furnace was calculated. 5 and 10% TiC nanopowder particles were added to the alloy as a modifier before pouring liquid metal into the ladle. This process was performed before pouring the liquid metal from the furnace into the ladle. 15% of TiC was added in the furnace as a modifier. Lagrangian interpolation polynomial construction was used in this modeling. The amount of wear resistance was calculated by polynomial expression of the function with determination of unknown coefficients. The results obtained on the basis of the developed model were compared with case studies. The results of the analysis are shown by graphs.

Abstract: Currently, native starch as a binder and sizing component is used extremely rarely due to its inherent disadvantages. It has been replaced everywhere with modified starches of various kinds. Studies have shown that polyelectrolyte flocculants can be created on the basis of starch if ionizable groups are introduced into the macromolecules of amylose and amylopectin. At the same time, it was found that the treatment of starch with oxidizing agents (of various natures and activities) can significantly improve the functional properties of native starch when gluing, used for surface sizing, and as a binder for corrugated cardboard. In this work, we also obtained oxidized starch in order to create an adhesive binder on its basis, and only local raw materials were used. It is shown that this method makes it possible to regulate the number of functional groups (oxidizing effect, or OE) in oxidized starch and its paste viscosity within a wide range. This is achieved by changing the molar ratio of the catalyst and oxidizer. During the oxidation process, it is possible to vary the concentration ratios of the oxidizer, catalyst, and conditions. Using FeSO₄ as a catalyzer, the oxidized starch pastes show a less pronounced pseudoplasticity and are characterized by reduced viscosity. The analysis showed that during the oxidation of corn starch with hydrogen peroxide, changes in the supramolecular structure of starch are insignificant: a certain repeated decrease in the level of crystallinity takes place, which leads to a decrease in the gelatinization temperature and also the viscosity of starch pastes.

Abstract: Bitumen, a fundamental component of asphalt used in road construction, plays a vital role in determining the performance and longevity of pavements. The assessment of bitumen characteristics is crucial to ensure its suitability for specific applications and environmental conditions. This research paper explores the use of fumed silica, a high-purity, fine particulate form of silicon dioxide, as an additive in bitumen to improve its properties. The study investigates the impact of Fumed Silica SiO2 on the results obtained. The following tests, including the specific gravity test, penetration test, softening point test, and flash and fire test were used to determine the rheological characteristics of bitumen. In particular, the treated bitumen qualities were concentrated after performing lab testing by breaking down the rheological properties. The research aims to enhance the understanding of how SiO2 affects bitumen properties and its potential benefits in enhancing the performance of road pavements. According to this study, 0.1 wt. % of fumed silica produces the results mentioned above better than larger concentrations of fumed silica.

Abstract: The understanding of the non-Arrhenius transport properties in glass-forming materials is of great importance from both, fundamental and applied points of views. In the present paper, we show that our model, the bond strength-coordination number fluctuation (BSCNF) model describes the temperature dependence of the non-Arrhenius transport coefficients in a wide temperature range. The BSCNF model also enables to characterize the glass-forming materials in terms of the mean values of the bond strength E₀, the coordination number Z₀ and their fluctuations ΔE and ΔZ of the structural units that form the melts. Importantly, in the light of the BSCNF model, one can discuss the physical implications of the materials that extend from the strong to fragile systems in a systematic way compared to other popular models. In addition, we present a new theory of the vacancy formation, and briefly mention that the extended theory along with the BSCNF model can be applied to discuss the freezing of defects.