Rotational Viscometer Research Articles

Effect of processing parameters on the properties of freeze-cast Ni wick with gradient porosity

Wicks are the main component of Loop Heat Pipe systems, whereby coolant liquid flow through their porous structure. They are usually formed by a primary wick to produce liquid transportation by capillary force, and a secondary wick that is continuously wetted by the liquid coolant. Traditionally, the two wicks are manufactured separately and subsequently joined, thereby creating an interface that reduces the liquid transfer efficiency. In order to overcome this situation, a gradient porous wick is proposed and successfully manufactured through the freeze-casting method in a single operation. The influence of two different dispersant agents, KD4® and stearic acid was studied on the processing parameters, final pore size and morphology, and capillarity performances. A variate of gradient porosity was obtained by applying a diverse thermal gradient and solidification front velocity during directional solidification. The rheological characterisation of the camphene-based NiO suspensions was performed using a rotational viscometer. The final pore size and morphology were characterised by Optical Microscopy, Field Emission Scanning Electron Microscopy, and X-ray computed tomography. The use of stearic acid improves the particle stabilisation and generates pore enlargement with an equiaxed pore structure, while commercial dispersant KD4® shows a dendritic pore morphology at lower thermal gradient.

Study on the Influence of Particle Size and Grade of Total Tailings on the Fluidity of High-Concentration Filling Slurry considering Strength

To find out the effect of total tailing particle size and grading on the rheological property of filling slurry with high concentration, especially in high intensity, the experiment on the particle size of total tailings was conducted firstly to get the corresponding result. Then, the collapse test of mixed slurry with different cement tailing ratios and different concentrations was carried out to get the corresponding slump value and extension value. Furthermore, the rotational viscometer was applied to test shear stress in the samples with different cement tailing ratios and different concentrations, from which the relevant rheological parameter can be achieved through the Bingham rheological model. Finally, a strength test to mixed slurry block with different cement tailing ratios and different concentrations was conducted (3 days, 7 days, and 28 days); the corresponding intensity values were taken. The experiment result illustrates that with the increase of concentration and cement tailing ratio of the slurry, the collapse degree and extended degree of slurry decreased, while yield stress, plastic viscosity, and strength increased. When the concentration was raised from 70% to 72%, all parameters that characterize good fluidity reduced obviously. As a result, the mixed slurry with a concentration of 70% and cement tailing ratio of 1 : 8 not only meets the requirements of production intensity but also has good mobility and low pipeline wear.

Feasibility of using micronized recycled Polyethylene Terephthalate (PET) as an asphalt binder additive: A laboratory study

The limited cost-effective avenues available for recycling Polyethylene Terephthalate (PET), widely used in packing bottled water, has turned it into a global environmental challenge. A number of studies have evaluated use of recycled PET bottles as an aggregate replacement in asphalt mixes. However, their outcomes indicated that performance of mixes did not significantly benefit from strength and high elasticity of PET. This study was undertaken to investigate the effect of incorporating different amounts (0, 5, 10, 15, and 20%) of Micronized PET (MPET) as a modifier in a PG 58-28 asphalt binder on its viscosity and adhesion to different types of aggregates. Also, the effectiveness of using MPET-modified asphalt binder in mixes for improving their resistance to rutting, cracking, and moisture-induced damage was evaluated. For this purpose, binder blends’ dynamic viscosities were measured using a rotational viscometer. Pull-off strength of MPET-modified binders with aggregates (two granite and one quartzite) was determined by conducting binder bond strength tests on dry and moisture-conditioned specimens. Surface Free Energy (SFE) analysis was also carried out to further understand the adhesion, cohesion, and debonding mechanisms. Furthermore, Superpave asphalt mixes containing MPET-modified PG 58-28 asphalt binder blends were prepared in the laboratory and their resistance to cracking, rutting, and moisture-induced damage was evaluated by conducting semi-circular bend, Hamburg wheel tracking, and tensile strength ratio tests. Testing asphalt binders and SFE analysis showed that, incorporation of MPET in asphalt binder significantly improved viscosity and binder-aggregate adhesion as well as their resistance to stripping. Additionally, testing asphalt mixes showed that, an increase in MPET content resulted in an increase in resistance to cracking, rutting, and moisture-induced damage. It was concluded that use of MPET as an asphalt binder modifier is an effective method for improving mechanical properties of asphalt pavements while addressing an environmental concern and preserving natural resources.

Establishment of calculation model for the viscoplastic heat production in friction stir welding process

Friction stir welding (FSW) is a solid-phase welding method. Weld forming and welding quality are related to the heat generated by plastic flow in FSW process. Therefore, it is of great significance to realize the measurement of the viscoplastic heat generated in FSW process. In this paper, based on the working principle of rotary viscometer, the calculation model for the viscoplastic heat in friction stir welding was proposed. The validity of the calculation model was verified by simulation experiment. The correctness of the calculation model was verified by friction stir welding experiment.

Styrene-Acrylic Emulsion with "Transition Layer" for Damping Coating: Synthesis and Characterization.

In order to study the dynamic mechanical properties of styrene–acrylic latex with a core/shell structure, a variety of latexes were synthesized by semi-continuous seeded emulsion polymerization based on “particle design” with the same material. The latexes were characterized by rotary viscosimeter, dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), dynamic mechanical analysis (DMA), and universal testing machine. The effects of difference at the glass transition temperature (Tg) of core and shell and the introduction of the “transition layer” on the damping and mechanical properties of latex film were studied. The results indicate that as the Tg of core and shell gets closer, the better the compatibility of core and shell, from phase separation to phase continuity. Furthermore, the introduction of the “transition layer” can effectively improve the tensile strength and tan δ (max) of the latex film. The tensile strength and maximum loss factor (f = 1 Hz) of latex with the “transition layer” increased by 36.73% and 29.11% respectively compared with the latex without the “transition layer”. This work provides a reference for the design of emulsion for damping coating.

Hybrid combinations of graphene nanoplatelets and phosphonium ionic liquids as lubricant additives for a polyalphaolefin

Tribological performance of three ionic liquids (ILs), trihexyltetradecylphosphonium bis(2-ethylhexyl)phosphate (IL1), tributylethylphosphonium diethylphosphate (IL2) and trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate (IL3) combined with graphene nanoplatelets (GnP) as hybrid additives for a polyalphaolefin (PAO 32) base oil was studied. For this purpose, several dispersions were prepared by mixing, stirring, and then sonicating according to the following combinations: PAO 32 + (a wt%) IL + (b wt%) GnP, where a and b represent the concentration of the additives added to the PAO 32 base oil. In this study a is 0 or 1 and b is 0.05 or 0.1. Three PAO 32 + 1 wt% IL mixtures were also prepared. Thermophysical properties and stability against sedimentation of the dispersions were studied by means of a rotational viscometer and visual observation, respectively. Furthermore, friction and wear behaviors were analyzed using a ball-on-disk configuration tribometer operating in rotational mode and both a 3D optical profiler and a scanning electronic microscope, respectively. Confocal Raman microscopy was used to identify compounds in the tribofilms formed on the wear tracks. The hybrid combinations of PAO 32/ILs/GnP improved the friction reduction of the corresponding binary PAO 32/GnP nanolubricants and PAO 32/IL mixtures. Interestingly, the hybrid dispersions with low concentrations of GnP (with 0.05 wt% GnP) are more effective than those of 0.1 wt% GnP. Results also show that the addition of both 0.05 wt% graphene nanoplatelets and 1 wt% IL led to friction reductions up to 36% and wear reductions up to 27%, compared with the capabilities of neat PAO 32. IL1 and IL3, containing the trihexyltetradecylphosphonium cation, generate the hybrid lubricants with the best combined properties (stability, viscosity and tribological properties) of all the lubricants tested.

Application of asphaltenes in high modulus asphalt concrete

The current study investigates the application of asphalt binders from different sources modified with asphaltenes in high modulus base courses (HMAC). For this purpose, one crude oil asphalt binder and four asphalt binders derived from various sources of Alberta oilsands were studied. Witczak regression model was used to determine the minimum performance grade to meet the dynamic modulus requirement for HMAC. Asphaltenes were added in different quantities for modification of the asphalt binders. The effect of asphaltenes modification on the viscosity of the binders was studied using a rotational viscometer. Also, the chemical composition of the asphaltenes-modified binders was determined by SARA analysis. The results of the rheological analysis indicated that asphaltenes effect on binders performance at high temperatures was more than its negative impact at low temperatures. Furthermore, it was determined that binders from the Alberta oilsands modified with asphaltenes could achieve the performance grade requirements for HMAC applications.

Viscosity Measurement Sensor: A Prototype for a Novel Medical Diagnostic Method Based on Quartz Crystal Resonator.

Viscosity variation in human fluids, such as Synovial Fluid (SF) or Cerebrospinal Fluid (CSF), can be used as a diagnostic factor; however, the sample volume obtained for analysis is usually small, making it difficult to measure its viscosity. On the other hand, Quartz Crystal Resonators (QCR) have been used widely in sensing applications due to their accuracy, cost, and size. This work provides the design and validation of a new viscosity measurement system based on quartz crystal resonators for low volume fluids, leading to the development of a sensor called “ViSQCT” as a prototype for a new medical diagnostic tool. The proposed method is based on measuring the resonance frequency at the crystal’s maximum conductance point through a frequency sweep, where crystals with 10 MHz fundamental resonance frequency were used. For validation purposes, artificial fluids were developed to simulate SFs and CFs in healthy and pathological conditions as experiment phantoms. A commercial QCR based system was also used for validation since its methodology differs from ours. A conventional rotational viscometer was used as a reference for calibration purposes. ViSQCT demonstrates the capability to measure the sample’s viscosity differentiation between healthy and pathological fluid phantoms and shows that it can be used as a basis for a diagnostic method of several pathologies related to the studied biological fluids. However, some performance differences between both QCR-based systems compared to the reference system deserves further investigation.

Preparation of UV‐thermal dual curable environmentally friendly polyacrylate pressure‐sensitive adhesives by bulk polymerization

AbstractThree different acrylate monomers containing butyl acrylate, 2‐hydroxyethyl acrylate, and acrylic acid were designed to synthesize polyacrylate pressure‐sensitive adhesives (PSAs) by bulk polymerization process initiated via radical photo‐initiators under UV irradiation and UV‐thermal dual curing. Thermal crosslinker, KL‐1202, with trifunctional isocyanate groups was introduced into the prepolymer to form an intermolecular crosslinking network structure. An emphasis was placed on the effect of the KL‐1202 content on the microstructure and adhesive properties of PSAs. The viscosity and composition of prepolymer synthesized by UV initiation were tested by a rotational viscometer and Fourier transform infrared spectroscopy, respectively. The degree of crosslinking of the final PSA was evaluated by the gel content value obtained via Soxhlet extraction, while the molecular weights of the soluble parts of PSA polymers were measured by gel permeation chromatography. Dynamic mechanical analysis was used to characterize the viscoelastic performance of PSAs. Moreover, the adhesive properties of PSAs were determined through a series of tests including loop tack force, peel force, and shear resistance. It was found that the C=C double bond and the isocyanate group disappeared after UV radiation and thermal curing process. Dual‐cure acrylate PSAs compensate for limitations in UV‐induced cure of thick coatings. The Tg value, storage modulus (G′), and shear resistance of PSAs were improved while the loop tack force and peel force of PSAs decreased as the KL‐1202 content increased.

Performance evaluation of asphaltic concrete incorporating milled egg-shell ash (mesa) as bitumen strength modifier and filler

Pursuant to the quest for sustainable and cheap pavement construction materials which have the potential of spurring the development of roads with low construction costs; and with the worrisome increase in the amount of eggshell wastes resulting from large consumption of poultry birds, this research assessed the engineering properties of bitumen modified with Milled Egg Shell Ash (MESA) and subsequently the performance of asphalt concrete with MESA as partial substitute for filler. Physicochemical characterization was carried out on the virgin bitumen and the MESA. Milled proportions of the egg shell ash was blended with bitumen at 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, followed by a complete substitution at 100%, by weight of mineral aggregates; and thereafter incorporated as filler using the same proportions. The penetrometer and rotational viscometer were engaged to determine the penetration and viscosity of the modified bitumen, and the Marshall mix design method was subsequently employed to determine the stability and flow of the asphaltic concrete composite. The modification of bitumen with egg shell ash resulted in a decrease in penetration of bitumen from 80/100 pen to 60/70 pen, as well as rotational viscosity met the required standard. Marshall stability decreased gradually with increased MESA content. Given the expected standard value of Marshall stability for wearing courses to be not less than 7.5 kN, the stability value of 31 kN obtained at 10% MESA, was recommended for sustainable pavement works. The X-ray Florescence (XRF) result showed a high presence of Calcium in terms of intensity and content in the Hot Mix Asphalt (HMA) modified with MESA, while the scanning electron microscope (SEM) provided a clear perspective of the interaction between the mineral aggregates, MESA, and bitumen in the entire HMA mixture. The results have shown feasible use of MESA as partial aggregate substitution in HMA which is recommended for light weight pavements or medium trafficked roads such as in found parking lots, walk ways, office complexes, university environments and short accesses.

Influence of polymer structure and amount on microstructure and properties of polyethylene-modified asphalt binders

In recent years, the use of polyethylene (PE) for asphalt modification has been gaining increased attention due to the environmental sustainability and cost-saving benefits. To optimize the performance of the PE-asphalt blends, it is necessary to understand the polymer-binder interactions and their impact on the properties of the modified asphalt binder. In this study, low-density polyethylene (LDPE) with low and high melt flow index (MFI), i.e., LDPE4 and LDPE70, were blended with Pen 60-70 asphalt binder in dosages ranging from 1 to 5 wt.%. PE Wax was also added to the binder or the PE-binder blend to enhance dispersion. The dispersion of PE in the binder and the phase stability of the modified binder were investigated by optical microscope. The equivalent diameter of PE domains increased with time and the polymer dosage level. The addition of PE wax improved the polymer dispersity in the LDPE4 blends. The polymer dispersity in LDPE70 blends was good without adding PE Wax, attributed to the higher MFI value (low molecular weight) of LDPE70. In addition, to understand the stability of polymer modified binder, the steady shear viscosity-temperature profile of these binders was studied using a rotational viscometer. The dynamic rheological properties and performance of the PE-binder blends were evaluated using the dynamic shear rheometer. Based on the microstructure, all other rheological and performance properties, it was concluded that the 3% LDPE70 binder has better polymer dispersity, better low and high temperature performance characteristics.

Study of structural and mechanical properties of sodium alginate gels

Rheological parameters are an important characteristic of semisolid dosage forms. Structural and mechanical characteristics have a noticeable effect on the processes of release and absorption of drugs from ointments, as well as on their consumer properties: spreadability, adhesion, the ability to squeeze out of the tubes.
 The aim: to study the rheological parameters of aqueous solutions of sodium alginate in various concentrations to create medicinal hydrogel compositions.
 Materials and methods: sodium alginate (Shandong Topsea Seaweed Industrial Co., Ltd., China) was used as a gelling agent. The physicochemical properties of the samples were studied according to generally accepted methods of the State Pharmacopoeia of Ukraine. Rheological studies of experimental samples were carried out using a rotational viscometer «Rheolab QC», by Anton Paar (Austria) with coaxial cylinders C-CC27/SS at a temperature 20–25 °С.
 Results and discussion: the rheological profiles of sodium alginate gels have a non-Newtonian type of flow, which makes it possible to characterize them as systems with plastic-viscous properties. Gels with a sodium alginate concentration of 1.5–2 % have the best indicators of yield stress, hysteresis loop area, mechanical stability and dynamic flow coefficients. This indicates a low degree of destruction of the structural grid in the process of mechanical action and the presence of thixotropic bonds.
 Conclusions: sodium alginate gel base at 0.5 % and 1 % concentration is less stable under stress compared to sodium alginate bases at 1.5 % and 2 % concentration. The gel base of sodium alginate at a concentration of 2 % has the optimal mechanical stability value.

Thermophysical Properties for ZnO-Water Nanofluid: Experimental Study

This paper presents the thermophysical properties of zinc oxide nanofluid that have been measured for experimental investigation. The main contribution of this study is to define the heat transfer characteristics of nanofluids. The measuring of these properties was carried out within a range of temperatures from 25 °C to 45 °C, volume fraction from 1 to 2 %, and the average nanoparticle diameter size is 25 nm, and the base fluid is water. The thermophysical properties, including viscosity and thermal conductivity, were measured by using Brookfield rotational Viscometer and Thermal Properties Analyzer, respectively. The result indicates that the thermophysical properties of zinc oxide nanofluid increasing with nanoparticle volume fraction increasing, as well as the thermophysical properties of zinc oxide nanofluid affected by the change in temperature.

Silane crosslinkable polyethylene waste as bitumen modifier: A new fortunate destiny by in time recycling of thermoplastic waste before conversion to thermoset end-of-life unrecyclable polymer

Polymer modification of bitumen is a popular method to enhance its performance. Over the years, researchers have suggested and developed various polymeric bitumen modifiers, and this trend in research is in progress to introduce new polymers with higher modification efficacies. Silane crosslinkable polyethylene is a widely used polymer as cable insulation, and its waste was used as bitumen modifier in this study. After shaping this polymer around the metal conductors and providing the crosslinking condition, silane-crosslinked polyethylene (Si-XLPE) insulation is obtained. When compared to ordinary polyethylene, Si-XLPE exhibits superlative performance, such as enhanced thermal, mechanical, elasticity, and stress cracking properties. Herein, the cable production wastes of this polymer were utilized for bitumen modification before crosslinking. Comprehensive analyses were carried out for characterizing the fabricated samples, including conventional physical (softening point, penetration, and storage stability), morphological (optical and fluorescence microscopies), chemical (FTIR), thermal (DSC), and performance grade (PG) assessments. For PG determination, rolling thin film oven (RTFO) and pressure aging vessel (PAV) tests, along with rotational viscometer (RV), dynamic shear rheometer (DSR), and bending-beam rheometer (BBR) tools were employed. Findings indicated the formation of a polymeric phase network in the bitumen matrix with altering shapes depending on the polymer content. This was identified to be the origin of appeared structural enhancements in the Si-XLPE modified bitumen samples. Moreover, it was revealed that Si-XLPE contents in 2% and more led to phase separations in the unaged or aged states due to high swelling ratio of Si-XLPE. Strikingly, it was seen that only 1% of Si-XLPE could change the PG 58-22 of base bitumen to PG 70-22, which confirmed promising efficiency of recycled Si-XLPE in low contents for significant improvements in the bitumen's high temperature performance without adverse effects on its low temperature performance. Eventually, recycled silane crosslinkable polyethylene can be an advantageous potential bitumen-modifier that is favorable from technical, environmental, and economical perspectives.

MOC Doped with Graphene Nanoplatelets: The Influence of the Mixture Preparation Technology on Its Properties.

The ongoing tendency to create environmentally friendly building materials is nowadays connected with the use of reactive magnesia-based composites. The aim of the presented research was to develop an ecologically sustainable composite material based on MOC (magnesium oxychloride cement) with excellent mechanical, chemical, and physical properties. The effect of the preparation procedure of MOC pastes doped with graphene nanoplatelets on their fresh and hardened properties was researched. One-step and two-step homogenization techniques were proposed as prospective tools for the production of MOC-based composites of advanced parameters. The conducted experiments and analyses covered X-ray fluorescence, scanning electron microscopy, energy-dispersive spectroscopy, high-resolution transmission electron microscopy, sorption analysis, X-ray diffraction, and optical microscopy. The viscosity of the fresh mixtures was monitored using a rotational viscometer. For the hardened composites, macro- and micro-structural parameters were measured together with the mechanical parameters. These tests were performed after 7 days and 14 days. The use of a carbon-based nanoadditive led to a significant drop in porosity, thus densifying the MOC matrix. Accordingly, the mechanical resistance was greatly improved by graphene nanoplatelets. The two-step homogenization procedure positively affected all researched functional parameters of the developed composites (e.g., the compressive strength increase of approximately 54% after 7 days, and 37% after 14 days, respectively) and can be recommended for the preparation of advanced functional materials reinforced with graphene.

Effect of laboratory-produced cellulose nanofiber as an additive on performance of asphalt binders and mixes

In recent years, major initiatives have been taken to replace non-renewable materials with environmentally friendly and sustainable ones. The present study was undertaken to apply a scalable process for laboratory production of Cellulose Nanofibers (CNF) and to evaluate feasibility of using the produced CNF as a sustainable plant-based asphalt additive to improve the mechanical properties and durability of asphalt pavements. To achieve this goal, CNF was produced in the laboratory by applying electrospinning technique. Structure, morphology, and the size distribution of the produced CNF were evaluated using Scan Electron Microscopy. Also, tensile strength tests in two perpendicular directions were conducted on lab-produced CNF. The effect of incorporating different amounts of CNF in three types of asphalt binders, namely PG 58-28, PG 64-34, and PG 70-28 on fracture energy and dynamic viscosity of binder blends were evaluated by conducting Izod impact and rotational viscometer tests, respectively. Additionally, effect of CNF dosage in binder on its adhesion and moisture-induced debonding potential with aggregates of three different mineralogy was evaluated by conducting binder bond strength test. Furthermore, effect of incorporating CNF in asphalt mixes on their cracking, rutting, and moisture-induced damage potential was evaluated by conducting semicircular bend, Hamburg wheel tracking, and tensile strength ratio tests, respectively. From the tests conducted on asphalt binders and mixes, it was concluded that, incorporation of CNF resulted in an overall improvement in binder-aggregates adhesion, an asphalt binder with a higher fracture energy and dynamic viscosity, and an asphalt mix with a higher resistance to rutting, cracking, and moisture-induced damage.

Microstructure and dynamic mechanical properties epoxy/asphaltene composites

Asphaltenes tend to aggregate to nanoparticles or clusters in crude oil and solvents over a wide concentration and temperature range. In the present paper, asphaltenes extracted from the base asphalt was used as a filler to introduce into epoxy resin. The microstructure and evolution of asphaltenes aggregation in the epoxy resin were observed using laser scanning confocal microscopy. Furthermore, the effect of asphaltenes on the viscosity, dynamic mechanical behavior, thermostability, mechanical properties of epoxy resin was evaluated by Brookfield rotational viscometer, dynamic mechanical analysis, thermogravimetric analysis and universal testing machine. The presence of asphaltenes increased the viscosity of the neat epoxy during all stages of cure reaction. The viscosity of epoxy/asphaltenes composites increased with the filler concentration. Fractal asphaltenes aggregation formed in the composites with 1 mass% asphaltenes. Network microstructures of asphaltenes aggregation appeared in the epoxy phase with a further increase of asphaltenes content. Moreover, the increase of asphaltenes loading resulted in denser network microstructures in the epoxy matrix. Aggregation evolution revealed that asphaltenes particles redispersed evenly in the epoxy resin in the form of some aggregates at the beginning of curing. During the cure reaction of epoxy, asphaltenes aggregates started to agglomerate and grow to network microstructures. The presence of asphaltenes led to the enhancement of the storage modulus of the neat epoxy at the rubbery stage. The glass transition temperature (Tg) of the epoxy composites slightly increased with the increase of asphaltenes loading. The epoxy composite with 5 mass% asphaltenes had higher Tg than the neat epoxy. The inclusion of asphaltenes had a negligible effect on the damping properties and thermal stability of the neat epoxy. The aggregation and heterogeneous dispersion of asphaltenes resulted in the decrease of the tensile strength and elongation at break of the neat epoxy. However, the inclusion of asphaltenes significantly enhanced Young’s modulus of the neat epoxy. Young’s modulus of the neat epoxy was increased by more than fourfold with the addition of 5 mass% asphaltenes.

Measurement of Fish Gelatin using Rotational Viscometer: An Alternative to Conventional Pipette Method

The pipette method is a conventional method commonly used for determining the viscosity of gelatin. The purpose of this research was to study the use of a rotational viscometer to measure the viscosity of fish gelatin. The rotational viscometer has a wide measuring range and a limitation on low viscosity liquid measurements such as fish gelatin, so it is necessary to verify the sensitivity of the rotational viscometer to measure the viscosity of fish gelatin. In this study, low range manual rotational viscometer (MLV), low range digital rotational viscometer (DLV), low range digital rotational viscometer with low viscosity adapter (DLV + UL) were tested for their sensitivity to read standard solutions of 4.8 cP and 48.8 cP. The results showed that DLV + UL generated a high accuracy in reading 4.8 cP and 48.8 cP standard solutions with the recovery value of 102.5% and 99.5%, respectively. Measurement of the viscosity of commercial fish gelatin seven times obtained a coefficient of variance of 2.98% indicating a high degree of precision, with a recovery value of 103.54% of the value of the secondary reference material analysis certificate. The number of samples required for DLV + UL is 16 mL, while the conventional method required a sample of 100 mL. We proposed using DLV + UL for testing the viscosity of fish gelatin.

Rheological Model of the Full Flow Curve of Highly Viscous and Solidifying Oil at Starting and Steady-State Mode Conditions

The article is devoted to the need of taking into account the thixotropic properties of oils when oil pipeline starts after a long stop, as well as to calculation of the time of its safe stop. To evaluate the parameters of thixotropy, it is proposed to use the results of laboratory experiments of oil samples on a rotary viscometer. Typical properties of the rheological flow curves of thixotropic oils for the starting flow mode are determined. The use of the wave equation of damped vibrations is proposed to describe the rheological flow curve of the forward course of measurements of a rotational viscometer, characterized by the presence of ascents and descents of shear stresses. This equation, supplemented by a model of nonlinear-visco-plastic liquids, allows accurately finding the areas of appearance of thixotropic properties of oils. The article presents the results of experimental studies of the manifestation of thixotropic properties of two oil samples at a lower temperature. The wave equation of damped vibrations allows describing mathematically the ascents and descents of shear stresses observed at low oil temperatures. Experiments have shown that the wave properties of thixotropic oil do not change with a decrease in temperature except for the amplitude of maximum vibrations and are invariant properties of the studied liquid. The presented explanation of the physical mechanism for the manifestation of wave properties based on the hardening of the supramolecular paraffin crystal lattice characteristic of thixotropic oils explains the invariance of the frequency change function and the attenuation coefficient during starting processes at the beginning of the movement of the movable cylinder of a rotary viscometer. The result of laboratory studies allows determining the nature of changes in the contours of the zones of manifestation of thixotropic oil properties as a dependence on the temperature and shear rate.

Sustainability Assessment of the Engineering Properties of Asphalt Concrete Incorporating Pulverized Snail Shell Ash as Partial Replacement for Filler

In furtherance to the search for reliable and cost-effective road construction materials which is expected to engender the development of sustainable and less expensive pavements, coupled with the increase in agricultural wastes due to the current rise in the consumption of white meat, this research investigated the engineering properties of modified bitumen and subsequent performance of asphaltic concrete incorporating Pulverized Snail Shell Ash (PSSA) as strength modifier and filler. In order to achieve specific objectives, preliminary physical and chemical tests were initialized to characterize the virgin bitumen and snail shell ash. Pulverized proportions of the snail shell ash were blended with bitumen at 10 %, 20 %, 30 %, 40 % and 50 % respectively by weight of mineral aggregates; and subsequently incorporated as filler at the same proportions. The rotational viscometer and penetrometer were engaged to determine the viscosity and penetration of the modified bitumen, and the Marshall mix design method was used to determine the mechanical and rheological characteristics of the resultant asphaltic concrete composites. The modification of bitumen with snail shell ash resulted in a decrease in penetration of virgin bitumen from 80/100 pen to 60/70 pen, including the rotational viscosity. Different mixtures of PSSA at the aforementioned proportions, were evaluated by the design method according to Marshall. The stability was found to be higher than the control mix at 30% of grade which satisfied the Marshall specification for wearing course mixes. X-ray fluorescence (XRF) showed the presence of Oxygen and Calcium in the Hot Mix Asphalt (HMA) modified with PSSA, while the scanning electron microscope (SEM) showed a good blend of the aggregates. The results suggest feasible use of PSSA as partial aggregate substitution in HMA. It was noted that the PSSA was finer than the conventional mineral filler and it filled the voids, engendered a stiffer, and denser mix, as well as reduced the number of voids present in the mix and increased its stability. Experimental results indicated higher stability value of 35.08 KN for the mixture having 30% PSSA as optimum filler content in comparison with conventional mix which was 34.7 kN and standard specification of 34 kN minimum. This study has therefore established the feasibility of using PSSA as alternative filler instead of the conventional in asphalt concrete mix by satisfying the standard specification. Also making the reuse of agricultural waste possible, thereby making construction cost cheaper, and also reducing waste.