Blending Law Research Articles

Diffusion kinetics of vitamin B6 released from bicontinuous and phase-inverted gelatin-agarose co-gels using blending-law modelling

In this study, gelatin and agarose were used as the phase-separated biopolymer system and vitamin B6 served as the diffusant. FTIR analysis confirmed the absence of any chemical interactions between gelatin, agarose, and vitamin B6 under the experimental conditions of this investigation. XRD analysis validated that vitamin B6 was homogenously dissolved in the composite low-solid system. Polarised light microscopy provided insights into the mixture topology and tangible evidence of the formation of bicontinuous and phase-inverted gelatin-agarose composite gels. Small-deformation dynamic oscillation was performed to establish theoretical blending law modelling, which predicted the phase volume and effective concentration of individual components (gelatin and agarose) in their respective domains. Then, a diffusion study was conducted and a novel blending law for diffusion was proposed to estimate the theoretical diffusion coefficient of vitamin B6 in the composite gel by utilizing the effective concentration of each polymer in their phase. Outcomes were compared positively to the observed diffusion coefficient from UV–vis analysis. Results demonstrate that blending-law diffusion theory can be utilised to ascertain the molecular transport of hydrophilic vitamins released from aqueous biopolymer composites.

Rheological characterisation of rejuvenator blending lines

Three different rejuvenators are blended with a differently-aged penetration graded asphalt binder 50/70 and investigated using different rheological test methods. Characteristic temperatures T(G* = 15 kPa) and T(G* = 5 MPa) as well as corresponding phase angles δ(G* = 15 kPa) and δ(G* = 5 MPa) are used to evaluate the efficiency of the rejuvenators, to obtain blending lines and to determine required rejuvenator dosage. Each rejuvenator acts slightly different depending on the dosage and linear blending laws can erroneously affect dosage calculation, especially for high dosages. Moreover, the required rejuvenator dosage is different in the high-temperature range according to temperatures T(G* = 15 kPa) compared to intermediate temperature range according to T(G* = 5 MPa). The blending lines of different rejuvenators are of great use for evaluating rejuvenator effectiveness in the high-temperature range. In addition, relaxation tests seem to be suitable for low-temperature evaluation.

Diffusion kinetics of vitamin B6 from phase-separated gelatin and agarose gels using blending law modelling

This study was conducted to understand the diffusion kinetics of vitamin B6 from composite gels of gelatin and agarose via blending law and diffusion modelling. Fourier-transform infrared spectroscopy (FTIR), X-ray Diffraction (XRD), confocal laser scanning microscopy (CLSM) and small-deformation dynamic oscillation in shear were used to analyse the structural properties of the composite gels. UV–vis spectroscopy was employed to study the diffusion kinetics of vitamin B6 from the gelatin-agarose gels. FTIR confirmed the absence of chemical interactions between gelatin and agarose in the mixture. XRD demonstrated that vitamin B6 was thoroughly hydrated in the polymeric mixture that balanced disordered polymer segments with structured junction zones. CLSM provided tangible evidence of the phase-separated nature of the two macromolecules, and blending law predicted the phase volume and their effective concentrations in the system. The diffusion of vitamin B6 from composite gels, prepared with estimated phase volumes and effective concentrations of the individual components according to rheological blending law, was measured with UV–vis spectroscopy. As far as we are aware, for the first time, rheological blending law was recast to provide the corresponding blending law for diffusion. Thus, theoretical diffusion coefficients were calculated and compared favourably with those from the experimental studies. Results argue for the presence of a blending law-based diffusion theory that can predict the diffusion kinetics of bioactive compounds in aqueous composite gels.

Balancing Convenience and Connection: Blending Law School Teaching and Learning During a Pandemic

This article reports on the lived experiences of 30 students completing a two-week intensive course on Dispute Resolution (DR) at the University of Western Australia Law School in 2021. The course was delivered fully-online in the first week, and in a traditional face-to-face setting in the second week. The adoption of online learning was in response to a government-mandated lockdown to combat the ongoing COVID-19 pandemic. The pandemic created a new landscape for higher education providers, where teachers needed to implement rapid adjustments to the delivery of legal education. By providing students with activities designed to capture their experiences with face-to-face and online delivery modes in the context of DR, Law School staff were able to gain valuable insight into the life of a law student during this time. The qualitative and quantitative findings revealed that the transition to online delivery was in some ways paradoxical, as students reported both benefits and limitations. This article contributes to accumulating literature exploring the impact of online delivery of education within a law school context, highlighting the potential barriers and facilitators to effective implementation identified by students. Further inquiry remains imperative in a post COVID-19 landscape where online delivery is increasingly relevant.

Laminar burning velocity blending laws using particle imaging velocimetry

One of the most essential inherent characteristics of a combustible mixture is laminar burning velocity. Because of its relevance, many methods for measuring laminar flame velocity have been devised. One advanced procedure was used to derive laminar burning velocity in a constant volume vessel for blends of iso-octane and n-heptane/air mixtures in this study: particle imaging velocimetry. Based on a precise flow field with vectors, particle imaging velocimetry (PIV) provides highly accurate laminar burning velocities. The results of the PIV method were compared with Schlieren data and simulations based on detailed LLNL gasoline surrogate chemical kinetics. It was found that the measured laminar burning velocities using the PIV method were more consistent. To predict the laminar burning velocity of the binary mixture of primary reference fuel (PRF) investigated in this study, five blending laws were used and all of them demonstrated strong application and high accuracy. The Leeds Q/k law based on the variation curve of the heat release rate/reaction process was found to have a strong predictive capability as well.

Quantification using rheological blending-law analysis and verification with 3D confocal laser scanning microscopy of the phase behaviour in agarose-gelatin co-gels

The efficacy of commercially available image analysis software was evaluated in the quantification of 3D images captured with confocal laser scanning microscopy (CLSM). The focus was on the phase behaviour of a mixed system of agarose and gelatin that was allowed to gel by controlled cooling to refrigeration temperature. Microstructural characteristics of the binary system were first probed with FTIR and microDSC to document the development of phase separated networks. Rheological experiments in the form of small-deformation dynamic oscillation in-shear were then employed to monitor the formation of a gelatin continuous network throughout the range of experimental concentrations tested. Agarose, on the other hand, formed discontinuous inclusions at low concentrations that inverted to another continuous phase, alongside that of gelatin, at the high end of polysaccharide addition in the mixture. Blending law analysis was able to model the phase behaviour of these preparations in relation to the mechanical strength of each polymer phase and its water holding capacity. Depending on the principle of operation, image analysis software sampled phase volumes in the co-gel that were either a close match to the predictions of blending laws or yielded statistically different values. Imaging software outcomes are discussed with a view to developing an alternative tool for estimating phase morphology in composite biopolymer gels. • Blending law can follow the phase behaviour of agarose-gelatin composite gels. • 3D CLSM imaging paired with image analysis generates a Z-stack of the composite. • Volumetric quantification of agarose-gelatin phase volumes matched the predictions of blending law. • A rapid microscopy protocol can replace blending law in determining composite morphology.

Structure analysis of multi-component pastes – The effect of water distribution on the rheological properties

Techno-functional properties of multi-component blends and ingredients are determined by the contribution of each ingredient and the water distribution between those ingredients in the blends. However, ingredients can consist of multiple components, which should be considered to better understand the properties of ingredients and blends thereof. Recently, empirical models were used to describe the viscosity of mildly refined ingredient blends. While many compositions were described well by the empirical models, blends with high fiber contents were not predicted sufficiently well. Therefore, in this research, the multi-component blends of commercial pea protein, pea starch, and pea fiber isolates were investigated on their rheological properties as a function of dry matter content. The same properties were then measured for blends of two of these isolates mixed in different ratios. From the rheological experiments, estimations of the water distribution were made with the polymer blending law. The results were compared with CLSM images. A quantitative analysis of the CLSM images mostly confirmed the model outcomes. The isolate ratio could describe the isolate blends sufficiently well, meaning that it was not necessary to know the exact compositions of the ingredients. It was concluded that changes in meso-structure of the blends, for example a phase transition at high fiber contents, caused the lower predictability by the recently published empirical viscosity models. This study demonstrates that the water distribution in multi-component blends plays a crucial role for their viscoelastic properties and the contribution of the individual isolates and components. Moreover, these polymer blending laws that include water distribution provide extra mechanical insights into the fraction behavior in multi-component blends.

Shared human–robot path following control of an unmanned ground vehicle

This paper considers the shared path following control of an unmanned ground vehicle by a single person. A passive measure of human intent is used to blend the human and machine inputs in a mixed initiative approach. The blending law is combined with saturated super-twisting sliding mode speed and heading controllers, so that exogenous disturbances can be counteracted via equivalent control. It is proven that when the proposed blending law is used, the combined control signals from both the human and automatic controller respect the actuator magnitude constraints of the machine. To demonstrate the approach, shared control experiments are performed using an unmanned ground vehicle, which follows a lawn mower pattern shaped path.

Methane hydrogen laminar burning velocity blending laws in horizontal open-ended flame tube rig

Different fuel properties and chemical kinetics of two different fuels would make it challenging to predict the combustion parameters of a binary fuel. Understanding the effect of blending methane and hydrogen gas is the main focus of this paper. Utilizing a horizontal tube combustion rig, methane-hydrogen fuel blends were created using blending laws from past literature, over a range of equivalence ratios from 0.6 – 1.2 were studied, while keeping one combustion parameter constant, the theoretical laminar burning velocity. The selected theoretical laminar burning velocity for all the mixtures tested were kept constant at 0.6 ms−1. Different factors affected the flame propagation across the tube, including acoustic pressure oscillations, heat loss from the rig, and obvious difference in hydrogen percentage in the fuel blends. The average experimental laminar burning velocity of all the flames was 0.368 ms−1, compared to the expected value of 0.6 ms−1. In an attempt to keep the theoretical laminar burning velocity constant for different mixtures, it was discovered that this did not promise the same flame propagation behaviour for the tested mixtures. Further experimentation and analysis are required in order to better understand the underlying interaction of the fuel blends.

3D Confocal Laser Scanning Microscopy for Quantification of the Phase Behaviour in Agarose-MCC co-gels in Comparison to the Rheological Blending-law Analysis

The need for a rapid and direct alternative to the rheology-based blending laws in quantifying phase behaviour in biopolymer composite gels is explored in this study. In doing so, the efficacy of confocal laser scanning microscopy (CLSM) paired with image analysis software – FIJI and Imaris - in quantifying phase volume was studied. That was carried out in a model system of agarose with varying concentrations of microcrystalline cellulose (MCC) in comparison to the rheological blending laws. Structural studies performed using SEM, FTIR, differential scanning calorimetry and dynamic oscillation in-shear unveiled a continuous, weak agarose network supporting the hard, rod-shaped MCC inclusions where the composite gel strength increased with higher ‘filler’ concentration. The phase volumes of MCC, estimated with the microscopic protocol, matched the predictions obtained from computerized modelling using the Lewis-Nielsen blending laws. Results highlight the suitability of the microscopic protocol in estimating the water partition and effective phase volumes in the agarose-MCC composite gel.

Phase volume quantification of agarose-ghee gels using 3D confocal laser scanning microscopy and blending law analysis: A comparison

A thorough understanding of the phase behaviour of biomaterial composites is imperative for manipulating the structural and textural properties in novel food products. This study probed the phase behaviour of a model system comprising agarose and a varying concentration of ghee. Results obtained from scanning electron microscopy (SEM), micro differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and dynamic oscillation in-shear revealed discontinuous and hard inclusions of ghee reinforcing the continuous, weaker agarose matrix with increasing concentrations of the former. Phase behaviour of the system was quantified in parallel with a novel method combining 3D confocal laser scanning microscopy (CLSM) imaging and image analysis software - FIJI and Imaris - in an effort to substantiate the efficacy of the microscopic protocol in quantifying phase behaviour. Phase volumes recorded with the microscopic protocol were in close agreement to those modelled with the Lewis-Nielsen blending law using small-deformation dynamic oscillation. However, results indicated that the inner filtering effect or ‘self-shadowing’ observed commonly in CLSM images may pose a limitation to the application of this technique, necessitating further development before it can be applied to more complex, industrially relevant systems.

Water redistribution determined by time domain NMR explains rheological properties of dense fibrous protein blends at high temperature

Blends of different plant proteins can form excellent basis for meat analogues by subjecting those to shear and heating. We here want to obtain more information of the internal structure of pea protein-gluten and soy protein-gluten blends, by using the polymer blending law to explain rheological responses. For this polymer blending law the water distribution over the two phases is the blend was obtained with time domain 1H NMR measurements using the NMR measurements of individual protein phases and on the blend. By matching the relaxation rate (R2) of the individual phases with those of the blend, the water distribution over the two phases could be obtained. Water is preferentially taken up by the soy or pea protein phase leaving less water for gluten, which effect strongly changes the volume fractions of the phases. Rheological properties of the separate phases as function of their hydration resulted in higher apparent modulus for the wheat gluten phase, and a lower one for the pea and soy protein phase. From the results, it was concluded that both blends show signs of a bi-continuous morphology. The SPI-WG blend showed an intermediate value between bi-continuous and SPI continuous. PPI-WG at lower temperatures showed a bi-continuous structure, while at higher processing temperatures and time was probably WG continuous.

Quantitative analysis of the phase volume of agarose-canola oil gels in comparison to blending law predictions using 3D imaging based on confocal laser scanning microscopy.

Studying the phase behaviour of composite gels facilitates understanding of their structural and textural properties at low and intermediate levels of solids. In this work, the phase behaviour of a model system of agarose including various concentrations of canola oil was studied. This was pursued using a variety of techniques including SEM, FTIR, microDSC and dynamic oscillation in-shear. The structural studies recorded strong, continuous agarose networks supporting soft, discontinuous canola oil inclusions, with increasing levels of canola oil strengthening the composite system. A novel confocal laser scanning microscopy (CLSM) method for quantitative in situ examination of the oil phase volume was developed using three-dimensional (3D) imaging and image analysis software - FIJI and Imaris. Microscopic observations were assessed in relation to theoretical predictions from rheology-based blending-law analysis. Quantitative outcomes from the combined 3D imaging and image analysis are in close agreement with the volume predictions for the oil phase obtained from the isostrain blending law indicating the suitability of this approach in quantifying the phase behaviour of composite materials. The results of this work indicate that the developed microscopic method shows promise and could be used in the determination of phase volume in more complex and industrially relevant systems.

Experimental investigation of blending phenomena in intergranular zones of recycled asphalt mixtures using customized infrared imaging and stage extraction methods

Abstract In the recycling road industry, a fundamental knowledge of blending mechanisms between the aged and virgin binders is necessary. An infrared imaging methodology is customized to assess the blending in different recycled asphalt mixtures. Obtained results are compared to those of another stage extraction technique. Both methods show that RA materials behave differently according to the process. Furthermore, the infrared methodology is highly-sensitive to understand blending scenarii: as remobilization is lower in warm-mix processes, the intergranular zone appears less oxidized and more homogeneous. This study encourages mix designers to optimize current blending laws with the introduction of a remobilization degree.

Homogeneity for Shared Control in the Presence of Disturbances

This paper considers the shared control of a second order plant by a single machine and one person in the presence of exogenous disturbances. A mixed-initiative blending law that takes a passive measure of human intent as the input to a convex pair of exponential functions is proposed. The blending law is combined with a disturbance observer and homogeneous trajectory-tracking control law, which dynamically rescales to ensure that actuator magnitude constraints are respected. The globally uniform ultimate boundedness of the closed loop automatic controller is proved. The shared control system is tested in a simulation where a human user can impose a control input using a joystick. Even if large tracking errors are commanded by the user, the automatic controller is able to quickly return to tracking the desired path when the joystick is released.

Modeling water partition in composite gels of BSA with gelatin following high pressure treatment

Changes in the structural properties of hydrogels made with gelatin and bovine serum albumin mixtures were recorded following exposure to high pressure at 300 MPa for 15 min at 10 and 80 °C. Dynamic oscillation, SEM, FTIR and blending law modelling were utilised to rationalise results. Pressurization at the low temperature end yielded continuous gelatin networks supporting discontinuous BSA inclusions, whereas an inverted dispersion was formed at the high temperature end with the continuous BSA network suspending the discontinuous gelatin inclusions. Lewis and Nielsen equations followed the mechanical properties of the composites thus arguing that solvent partition between the two phases was always in favour of the polymer forming the continuous network. As far as we are aware, this is the first attempt to elucidate the solvent partition in pressurised hydrogel composites using blending law theory. Outcomes were contrasted with earlier work where binary mixtures were subjected only to thermal treatment.

Laminar flame properties of C1-C3 alkanes/hydrogen blends at gas engine conditions

The use of fuel blending is encouraged in order to achieve more flexibility in gas engines. In order to design such engines effectively, relevant information about the laminar flame speeds and laminar flame thickness are necessary. Hydrodynamic and thermo-diffusive instabilities at gas engine conditions prevent the acquisition of reliable data experimentally. One-dimensional numerical simulations with detailed chemistry can be a solution. A huge database of laminar flame speeds is generated covering a broad range of gas engine applications, pressure (p) 0.1–20 MPa, fresh gas temperature (Tu) 300–1100 K, air-fuel equivalence ratio (λ) 0.9–2.5, methane 100–60 vol%, ethane 0–40 vol%, propane 0–40 vol%, hydrogen 0–30 vol% and exhaust gas recirculation (EGR) 0–30 m%. The detailed reaction mechanisms GRI 3.0 and AramcoMech 1.3 are used for the generation of flame speed data for the mentioned conditions. A laminar flame speed correlation for 100% hydrogen extending up to elevated pressure and temperature conditions is developed. A blending law based on Le Chatelier’s rule is investigated. It is observed that the HC-ratio has a very determining effect for the laminar flame properties of different C1-C3 alkane blends. Based on this observation, it was possible to derive a very efficient correlation for both laminar flame speed and laminar flame thickness for the group of natural gas blends with methane, ethane, propane and hydrogen, and as well as including relevant EGR, which corresponds within 7% accuracy to the calculated database of about 73,000 points. The developed laminar flame speed correlation is incorporated in an engine process simulation code. It is validated with the measured in-cylinder pressure traces from the single cylinder research engine experiments for different gas blends and EGR ratios.

Effect of Saccharide and Alditol Additives on Uniaxial Tensile Behavior of Gellan Films

The uniaxial tensile behavior of gellan films containing saccharides or alditols was examined to elucidate the plasticizing effect of these additives. Five saccharides as well as two alditols were used. The films were tested after removal of water as far as possible. The tensile modulus decreased as the content of the additives increased, suggesting apparent plasticizing effect of the additives. The plasticizing effect was discussed referring the glass transition temperature instead of the melting point of the additives, assuming the additives were in the “supercooled” liquid state even below the melting point. Since some additives showed similar values of tensile modulus regardless of whether the additive was in the solid state or in the liquid state, a blending law of the moduli was proposed to explain the apparent plasticizing effect. On the other hand, it was found that xylitol and two monosaccharides glucose and fructose acted as true plasticizers. The effective factor was attributed to the solubility of these additives to the gellan matrix. A relationship between the profile of the stress–strain curve and the plasticizing effect was also proposed.

Modeling counterion partition in composite gels of BSA with gelatin following thermal treatment

This study deals with the distribution of added calcium ions and their effect on the phase behaviour of hydrogels made of bovine serum albumin and gelatin. Structural properties of single and mixed systems were identified using small-deformation dynamic oscillation in shear, microdifferential scanning calorimetry and scanning electron microscopy. The experimental procedure was designed to encourage formation of micro phase-separated materials, where i) a continuous gelatin matrix supported liquid BSA inclusions, ii) an inverted dispersion of gelled BSA was interspersed by liquid gelatin inclusions and iii) a rigid BSA phase supported softer filler particles of gelatin. The Lewis-Nielsen equations and a series of models developed by Takayanagi were adapted for predicting the phase behaviour of BSA/gelatin mixtures in the presence of added calcium chloride. As far as we are aware, this is the first attempt to model the partition of added counterions between polymeric phases in binary hydrogels based on classic blending law analysis.

Modeling water partition in composite gels of BSA with gelatin following thermal treatment

A thorough experimental procedure of controlled cooling, isothermal at low temperature, heating, isothermal at high temperature and a second cooling run were carried out to record and rationalise the structural properties of BSA-gelatin mixtures over a wide range of temperature and polymer concentration. Research methodology included small-deformation dynamic oscillation in-shear, micro-differential scanning calorimetry, scanning electron microscopy and semi-theoretical modeling based on ideas of relating the elastic modulus of amorphous synthetic polymers to the topology of their binary blends. Cooling of solutions from ambient temperature produces gelatin continuous matrices supporting the BSA droplets, and modeling of the mechanical readings using an appropriate Lewis-Nielsen equation argues that the former is a highly hydrophilic molecule. Heating melts the gelatin network and leads to the formation of a continuous BSA structure, with dispersed inclusions of liquid gelatin, but produces a solvent partition factor in favour of the globular-protein gel. Subsequent cooling forms solid-like particles of gelatin within the interstices of the continuous BSA network. Modeling of steric exclusion phenomena in this filler composite using the isostrain blending law further supports the concept of increasing proportions of water being trapped within the continuous matrix of a biphasic gel.