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The aim of this study is to investigate the changes in different physicochemical, texture and sensory properties of milk fermented with different strains during the storage. An experimental study of the effect of the storage time on the physicochemical and rheological properties of milk fermented with commercial starter (StLb) and the same starter with a probiotic Lactobacillus salivarius LS adjunct was carried out. The effect of the storage on the pH, titrable acidity, lactic acid concentration, microorganisms count, gel firmness and rheological parameters is investigated. During the fermentation a stable decrease of the pH values and increase in the titrable acidity was observed. Through the whole storage period at 4°C (till 28th day) the both fermented milks kept stable rheological and organoleptic properties. This determines the fermented milk as a suitable form for oral administration of tested probiotic strain LS. The rheological tests showed that the products studied demonstrated non-Newtonian behaviour, which could be described with Herschell-Bulkley rheological model. A correlation between the model parameters and the results of the penetration test was found. The results of this study can be used in production of new fermented milk products with functional properties. [ABSTRACT FROM AUTHOR]

Wood as a performance material, know an increasingly and wider applications in various fields. Due to macroscopic, microscopic and chemical structure, it is a material with important rheological properties. Knowledge of the rheological behavior helps engineers and researchers to predict lifetime of wooden structures, the strains and their stability over time. The paper aims to determine complex elasticity modulus and damping which expressed the rheological behavior of two wood species (alder and beech). The samples were subject to cyclic stresses under the same conditions (constant temperature, constant load, frequency and duration) using dynamic mechanical analysis device (DMA). To emphasize the different behavior of wood on different section, it was considered four cases of load. Results indicated that dynamic modulus is lower than one determined at static bending, but in correlation with main section of wood. This means that in real condition of applications, it is recommended to take into account the rheological behaviour of wood and the elasticity of them to cyclic stresses. Secondly, the wood recorded different behaviour in accordance with direction of force/moment related to fibres directions. Damping is higher at beech wood compare to alder in case of longitudinal flexure; the values of beech damping d varied between 0.088 and 0.102, and for alder, 0.0748 to 0.095. [ABSTRACT FROM AUTHOR]

Wooden buildings are subjected to both short term and long term variable loads. The wood is better able to withstand high loads in a short period of time than for a longer period of time. The stress duration refers to the loss of strength, which must be considered as a phenomenon in its own right. Joints are the main areas in which the energy can be dissipated by the possibility of using the plastic capacity of those parts of the structure. The deformability is observed mainly when used mechanical clips in joints. One of the limits of the energy dissipation is wood breaking in the joint area. In assessing the mechanical properties of a wooden element, the regularity of growth, the presence, arrangement and dimensions of any knots or other defects must be taken into account. All these have influence upon the elastic-plastic properties of wood, showing continuous deformation under load (creep). This paper presents the results of numerical and experimental modeling of the rheological behavior of the wood joints in case of using simple rod and Bulldog rod stud type. In the first part of the study, the rod joint subjected to tensile stresses was modeled with FEM analysis, determining the displacement and the maximum stresses. In the second stage, the joints were subjected to tensile stresses and the curves stresses -- displacement and energy of deformation were extracted, then another set of specimens were subjected to tensile stresses, while being monitored the values of the climatic parameters and displacement values. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the influence of ultrasound and high-shear mixing on the properties of microparticles obtained by spray congealing. Dispersions containing 10% carbamazepine and 90% carrier Gelucire® 50/13 (w/w) were prepared using magnetic stirring, high-shear mixing, or ultrasound. Each preparation was made using hot-melt mixing spray congealing to obtain the microparticles. All microparticles presented a spherical shape with high encapsulation efficiency (>99%). High-shear mixing and ultrasound promoted a decrease in the size of microparticles ( D90) to 62.8 ± 4.1 μm and 64.9 ± 3.3 μm, respectively, while magnetic stirring produced microparticles with a size of 84.1 ± 1.4 µm. The use of ultrasound led to microparticles with increased moisture content as identified through sorption isotherm studies. In addition, rheograms showed distinct rheological behaviour among different dispersion preparations. Therefore, the technique used to prepare dispersions for spray congealing can affect specific characteristics of the microparticles and should be controlled during the preparation. [ABSTRACT FROM AUTHOR]

Highlights: [•] Ball–ball tests characterise appropriately interactions of aggregate particles in concrete. [•] Elastic and viscous force components from ball–ball tests correlate with rheological constants obtained from rheometer tests. [•] Carbopol solutions and cement-based mortars exhibit similar rheological behaviours. [•] Force–displacement curve for monotonic loading can serve as envelope curve for various loading scenarios. [•] Material model is developed for the interaction between discrete elements with some viscoelastic material between them. [ABSTRACT FROM AUTHOR]

High melt strength/block polypropylene (HMSPP/PPB) blends and high melt strength/random polypropylene (HMSPP/PPR) blends were prepared by a twin-screw extruder to decrease the high stiffness of polypropylene and to improve its impact strength. Rheological properties of the two blends were investigated using a rotational rheometer . The complex viscosity and storage modulus data at low frequency region indicated that the melt elasticity and melt strength of the blends were affected by varying the content of PPB and PPR in the blends. Moreover, the melt strength of HMSPP/PPR blends was better than that of HMSPP/PPB. The non-isothermal crystallization behaviour of the blends was studied using differential scanning calorimetry with various cooling rates and was analyzed by the Avrami method. It was found that the melt and crystallization temperatures of the blends increased with the ratio of PPR and PPB. PPB also changed the crystallization process of the blends, leading to smaller spherulite size and more spherulites, but PPR only slightly affected the crystal behaviour. [ABSTRACT FROM AUTHOR]

Abstract: Rheological properties define the functionality and consequently, the technological quality, of food proteins. This study deals with the effects of short-wave ultraviolet treatments (dynamic or static UV-C) on the dynamic viscosity, flow behaviour, temperature-dependent viscosity, thermal properties and electrophoretic patterns of liquid egg products. Remarkably, none of the investigated parameters have been significantly influenced by UV-C treatments, static or dynamic. Rheological data, and thermal and electrophoretic properties indicate that the flow behaviour of UV-C treated egg white, whole egg or egg yolk, has not varied, and relevant protein denaturation or aggregation could be discarded. On the contrary, heat pasteurizations caused an increase on the viscosity-shear rate dependency, and also a certain degree of coagulation could be observed in the flow behaviour diagrams. Pasteurization additionally caused a reduction on the denaturation enthalpy observed in temperature-dependence viscosity measurements, and in DSC thermograms. The electrophoretic profiles also confirmed a certain degree of denaturation after pasteurization, with a reduction in the amount and intensity of the observed proteins. These results indicate that UV-C treatments do not affect significantly the rheological properties and the protein profile of liquid egg fractions, and could be used as an alternative to pasteurization. [Copyright &y& Elsevier]

In the present study, powder injection moulding (PIM) was used to fabricate ultrafine 98W-1Ni-1Fe preform. The influence of various ball milling times (3, 5 and 10 h) on the characteristics of the ultrafine powder and the rheological behaviour of the injection moulded feedstocks has been investigated over the 105-145°C temperature range and the 1·79-596·1 s-1 shear range. The results show that all the feedstocks exhibit pseudoplastic flow behaviour. The increase in ball milling time could reduce the viscosity of the feedstock and enhance the shear stability by greatly diminishing the agglomeration of ultrafine particles. However, the powder ball milled for 5 h can produce a feedstock with better thermostability and comprehensive rheology. Therefore, compared with the powder ball milled for 3 and 10 h, the powder milled for 5 h is more suitable for ultrafine 98W-1Ni-1Fe PIM. [ABSTRACT FROM AUTHOR]

Abstract: The main objective of the current work was to characterize the shear rheological flow behaviour and emulsifying properties of the natural biopolymer from durian seed. The present study revealed that the extraction condition significantly affected the physical and functional characteristics of the natural biopolymer from durian seed. The dynamic oscillatory test indicated that the biopolymer from durian seed showed more gel (or solid) like behaviour than the viscous (or liquid) like behaviour (G′> G″) at a relatively high concentration (20%) in the fixed frequency (0.1Hz). This might be explained by the fact that the gum coils disentangle at low frequencies during the long period of oscillation, thus resulting in more gel like behaviour than the viscous like behaviour. The average droplet size of oil in water (O/W) emulsions stabilized by durian seed gum significantly varied from 0.42 to 7.48μm. The results indicated that O/W emulsions showed significant different stability after 4 months storage. This might be interpreted by the considerable effect of the extraction condition on the chemical and molecular structure of the biopolymer, thus affecting its emulsifying capacity. The biopolymer extracted by using low water to seed (W/S) ratio at the low temperature under the alkaline condition showed a relatively high emulsifying activity in O/W emulsion. [Copyright &y& Elsevier]

Vinyl acetate radical emulsion polymerization in water with GF51 silane co-monomer was performed by semi continuous way. The GF51 impacts on dispersion rheology as well on films and bonding strength properties were determined. It should be stated that even low quantities of GF51 (up to 6% from VAc) determined high viscosity of dispersions. The GF51 modified films have low water absorption and high affinity to glass. Molecular mass and thermal properties of GF51 modified polymers were determined accordingly. [ABSTRACT FROM AUTHOR]

Abstract: This paper focuses on the study on rheological behaviour of emulsions, stabilized by both differently modified dispersible colloidal Boehmite alumina nanoparticles and a non-ionic emulsifier. Hysteresis loop measurements and dynamic rheological measurements were carried out in linear and non-linear regimes on two different emulsion systems – water-in-oil (W/O) and oil-in-water (O/W) emulsions. Emulsion stabilized by a combination of moderately hydrophobic particles and a non-ionic emulsifier is an O/W emulsion. The addition of emulsifier improved the stability, however, did not show a significant influence on the emulsion flow behaviour. The emulsion, stabilized by both – nanoparticles and emulsifier – showed a complicated behaviour, i.e. sometimes it exhibited thixotropy or antithixotropy and sometimes both of them. Emulsion stabilized by rather hydrophobic particles and a non-polar emulsifier is a W/O emulsion. The emulsion is very homogenous and exhibited very weak thixotropy. Dynamic measurements showed that G’ was almost equal to G” and both parameters were frequency-dependent, indicating a viscous liquid-like system with little network structure if any. With addition of emulsifier, the rather elastic solid-like emulsion structure may be changed into the viscous liquid-like structure. In order to get a better understanding of relationships between rheological behaviour and microstructure, differential scanning calorimetry (DSC) results and optical microscopic images of the emulsions studied were discussed. [Copyright &y& Elsevier]

Copyright of Matériaux et Techniques is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Sequencing batch biofilter granular reactor (SBBGR) is a recently developed biological wastewater treatment technology characterised by a very low sludge production, among other numerous advantages. Even if costs for sludge treatment and disposal are mainly dependent on the amount of sludge produced, sludge properties, especially those linked to solid–liquid separation, play a key role as well. In fact, such properties deeply influence the type of treatments sludge has to undergo before disposal and the final achievable solids concentration, strongly affecting treatment and disposal costs. As sludge from SBBGR is a special mixture of biofilm and aerobic granules, no information is available so far on its treatability. This study addresses the characterisation of the sludge produced from SBBGR in terms of some physical properties (settling properties, dewaterability, rheology). The results show that such sludge is characterised by good settling and dewatering properties, adding a new advantage for the full-scale application of SBBGR technology. [Copyright &y& Elsevier]

Abstract: One of the techniques of old masonry consolidation is the injection of grouts. For a successful injection it is necessary to ensure an adequate flow of the grout inside the porous media, for which it becomes essential to control the grout rheological behaviour and stability. This paper analyses the influence of grout mixing procedures on rheological behaviour, water retention and stability of hydraulic lime grouts with superplasticizer. This research has particular relevance due to lack of information about the use of superplasticizers in hydraulic lime grouts, compared to the amount of information that exists in the case of Portland cement based mixtures. The research showed that fresh grout behaviour can be improved using an appropriate mixing procedure, optimised with the Taguchi method. [Copyright &y& Elsevier]

Abstract: The behaviour of low-Fe and high-Fe substituted chlorite mineral dispersions was investigated under industrially-relevant, atmospheric leaching conditions typical of low grade, uranium-bearing lateritic ore processing. The main focus was on the influential role played by the clay mineral chemistry. Preferential leaching of Al(III), Fe(II/III) and Mg(II) metal ions over tetrahedral Si species was indicated at pH 1 and 70°C by supernatant speciation, the kinetics of which was faster at high-Fe than at low-Fe substitution. For the low-Fe chlorite, the incongruent leaching behaviour of Al(III), Fe(II/III) and Mg(II) species was substantially similar. In the case of the high-Fe chlorite however, despite its lower Mg(II) content, Al(III) and Fe(II/III) species leaching rates were relatively lower than that of Mg(II). Crystallo-chemical (XRD, XRF and EM) and spectroscopic (FTIR and XPS) analyses indicated that the incongruent leaching led to significant bulk particle and interfacial layer structures'' modification, impacting dramatically upon pulp chemistry, mineralogy and particle interactions. Mineral chemistry-mediated formation of polycondensed, sub-crystalline aluminosilicate gel structures and secondary mineral phases prevailed in the course of leaching. A greater increase in high-Fe pulp particle interactions, in contrast with the low-Fe pulp, was observed during leaching, reflecting remarkably high, time-dependent shear yield stresses, reminiscent of highly viscous gels. The development of viscous gel structures whose strength is strongly dependent upon chlorite mineral chemistry has important implications for the efficacy of aqueous processing of clay-rich lateritic ores. [Copyright &y& Elsevier]

Abstract: An aluminous cement (Secar 71 from Lafarge) has been used for preparing millimetre thick films by tape casting. Slurry preparation is described. The effect of several dispersants has been studied. The optimum dispersion, associated with the minimum viscosity, is obtained with minimal amounts of dispersant in the case of acetic and propionic acids. Indeed, the corresponding quantities of dispersant are less than 0.5% by weight relative to cement. In addition to its dispersive role, acetic acid plays a role in the setting. It has a retarding effect below 1% by weight relative to the mass of cement and from this amount, it plays an accelerating role on setting. Tapes prepared with cement, water, acetic acid, PEG 300 have been left to set in different environments at 20°C (50% or 95% relative humidity, water). The formation of aluminous calcium hydrates is most important when setting is done in water. Lastly, the advantage of setting in water is also discussed with respect to the elimination of the different organic products that have been used for tape casting. [Copyright &y& Elsevier]

Abstract: Shellac is derived from the resinous secretion of the lac insect (Kerria lacca), mainly found in India. This biopolymer is made of natural single and polyesters of aliphatic acids and sesquiterpenoid acids. Ageing was investigated through interdisciplinary approaches to understand the behaviour and the interactions of macromolecules in the biological system. During ageing the viscoelastic properties of the polymer evolved in the sense of crosslinking of the macromolecules. The fate of the shellac backbone molecules was assessed. It was found that hydroxy fatty acid such as aleuritic acid could be a factor in the changes of the polymer consistency. Aleuritic acid could be freed from the polymer during its ageing after de-esterification and could participate through hydrogen bonding in the biopolymer crosslinking observed by melt rheology. [Copyright &y& Elsevier]

Linear extrapolation of the reduced viscosity values of uncharged polymer solutions as the concentration approaches zero constitutes the basis for the traditional method for the determination of the intrinsic viscosities of polymer solutions. While this method works well for uncharged polymer solutions, it fails completely for polyelectrolyte solutions especially in absence and also in presence of small amount of an added electrolyte. A very convenient method has recently been proposed by Wolf (Wolf, Macromol. Rapid Commun. 2007, 28, 164) to determine the intrinsic viscosities of polyelectrolyte solutions on the basis of the laws of phenomenological thermodynamics applied to the viscosity of polymer solutions. In spite of the success and the convenience of this method, this has so far been applied to a limited number of polyelectrolyte systems by the Wolf group alone (Wolf, Macromol. Rapid Commun. 2007, 28, 164; Eckelt et al., Macromolecules 2008, 41, 912; Badiger et al., Macromol. Chem. Phys. 2008, 209, 2087; Ghimici et al., J. Phys. Chem.B. 2009, 113, 8020). In order to improve the situation, we have measured the viscosities of an anionic polyelectrolyte, sodium polystyrenesulfonate, in methanol-water mixed solvent media both in absence and in the presence of an electrolyte, sodium chloride. The results show that the experimental data fit well with the Wolf model and thus allow the calculation of intrinsic viscosities, which provide important insight about the dependence of the polyion conformation on solvent composition as well as on the concentration of the added electrolyte. This new evaluation method, thus, proves to be very useful to a better understanding of the rheological behaviour of the polyelectrolyte system investigated. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HA) is extensively used in medical applications as an artificial bone because of its similarity to the natural components of human bones and for its excellent biocompatibility. The porous structure of HA ceramics is more generally used as a scaffold. Many techniques, which are performed under fluid system, have been applied to fabricate HA porous scaffolds. In this work, polymeric sponge technique was employed in the preparation of HA slurry appropriated for porous ceramic fabrication. Effort for strength improvement was made on porous HA ceramic in several aspects. The effect of HA/water, binder/plasticizer ratios and dispersant content on the rheological properties of HA suspension in combination with the addition of SiC and SiO on the compressive strength of porous bodies were investigated and discussed. [ABSTRACT FROM AUTHOR]

The gelation of agarose is investigated by rheological methods and electron microscopy, as well as the thickening properties of xanthan. The gelling and thickening agents have been investigated in pure water to compare the results with theoretical models. The gelation of agarose was shown to follow two steps upon cooling, which could be addressed to the formation of helices and their aggregation. In addition to the rheology, transmission electron micrographs of freeze-dried samples have been taken to underline the date by corresponding structures at different stages of the gelling process. The xanthan molecules, which have been approximated by rigid highly charged rodlike molecules, undergo a jamming transition at a critical concentration. This concentration shows a strong dependence on the length of the molecules, which supports the high thickening effect of xanthan. When both, agarose and xanthan are mixed, the gel structure becomes very different. The gelling process is now determined by one step only. It is proposed that the jamming xanthan molecules prevent the formation of the aggregates of the agarose gel. The gels themselves appear then less elastic, and should yield a better mouth feeling. [ABSTRACT FROM AUTHOR]

Abstract: Pectins account for one of the major polysaccharides of plant cell walls and are commonly used in the food industry as gelling and stabilising agents. Pectin methylesterase (PME) can alter pectin structure and affect their gelling properties by de-esterifying galacturonic acid. Previously, we reported different behaviours of plant and fungal PMEs on high methylated pectins in solution or during the gelling process (). In the present study, the behaviour of the two PMEs is studied on a medium methylated pectin in solution, i.e. in the absence of calcium, or during the gelling process, i.e. in the presence of calcium. Only slight modifications were observed for Aspergillus aculeatus PME behaviour between the two conditions. On the opposite we show a role of calcium on the processivity of orange PME: the processivity decreases in the presence of calcium. [Copyright &y& Elsevier]

One characteristic of the Romanian wheat flour in the recent years consists of high values of the falling number. The aim of the present study was to explore the Mixolab device to characterize the thermo-mechanical behaviour of flour supplemented with different additives that contain α-amylase. Mixolab parameters C4 and C5 were found to be lower in samples with high doses of additives containing α-amylases. The increase of the α-amylase dose reduces the dough stability. The samples that contain higher doses of additives presented low values of the β slope, which gives indications about starch gelatinization. The samples with reduced a-amylases activity showed high values of the γ slope. [ABSTRACT FROM AUTHOR]

Abstract: This study investigated phase behaviour, microstructure and solubilization capacity of pseudo-ternary surfactant/cosurfactant/isopropyl myristate/water systems employing complex mixtures of nonionic surfactants for formation of single-phase microemulsions. The surfactant was PEG-8 caprylic/capric glycerides (Labrasol®). A well defined mixture of octoxynol-12 and polysorbate 20 and/or PEG-40 hydrogenated castor oil, available as commercial nonionic surfactants Solubilisant gamma® 2421, Solubilisant gamma® 2429 and Cremophor® RH 40, respectively, were evaluated as cosurfactants. Surfactant+cosurfactant mixtures were treated as a single component (pseudo-component), since a surfactant-to-cosurfactant weight ratio (Km 50:50) was constant through the study. Phase behaviour study revealed enlargement of single-phase microemulsion area as surfactant+cosurfactant-to-oil weight ratio (SCoS/O) increases. The formation of fully dilutable microemulsions containing the maximum of water incorporation in the surfactant/cosurfactant/oil preconcentrates of Wmax ≥80% w/w, was achieved at SCoS/O 90:10. Microemulsions formed along the single-phase sequence at SCoS/O 90:10 in the presence of different cosurfactants, were characterized using polarized light microscopy, photon correlation spectroscopy (PCS), and rheological measurements. Different performances of complex mixtures of nonionic surfactants in stabilization of single-phase microemulsions were observed only in highly diluted oil-in-water microemulsions area. Investigation of solubilization capacity for poorly soluble drug ibuprofen revealed the critical importance of water-to-surfactant+cosurfactant ratio and penetration of oil at the interface. [Copyright &y& Elsevier]

Abstract: Unilateral solid state NMR and near infrared measurements are combined to study latex film formation at different temperatures and humidities in order to cover a broad parameter-space of film formation conditions. From analysis of nuclear magnetic resonance (NMR) data the time evolution of water and polymer fraction at different (vertical) positions in the film were estimated. The mean water fraction was determined simultaneously by near infrared (NIR) reflection measurements. From the time-evolution of the water distribution within the film and the total water content, it was possible to differentiate between the different deformation mechanisms (e.g. capillary deformation, receding water front mechanism or skin formation). The experimental findings are compared to theoretical predictions by Routh and Russel [Langmuir 15 (1999) 7762–7773]. Although most of the predicted regimes could be identified, the experimental estimated transitions between different regimes deviate significantly from the theoretical boundaries. The complex rheological behaviour of polymers has been identified to be the main reason for these deviations. [Copyright &y& Elsevier]

Abstract: The rheological behaviour of chitin in 8wt% NaOH/4wt% urea aqueous medium was evaluated by steady shear and dynamic oscillatory tests, in which the effects of concentration, temperature and time on the rheological behaviour of chitin aqueous solution were investigated in detail. It suggested that chitin aqueous solution is sensitive to temperature, which will transform to a gel when temperature increases to physiological conditions. And the higher the concentration is, the lower the gelation temperature is. The comparison on rheological behaviour of chitin aqueous solution at different time reveals that 8wt% NaOH/4wt% urea solvent at low temperature has little effect on chitin structure. It is interesting that the chitin gel has reversibility and it will transit to solution after being treated at low temperature again. The comparison on rheological behaviour between the original chitin aqueous solution and the chitin aqueous solution after gelation reveals that gelation has a little effects on solution properties. [Copyright &y& Elsevier]

Abstract: The structure of a foodstuff, and its perceived texture, are important characteristics involved in the sensory availability of flavour compounds released during the food consumption. This study identifies the effect of texture on the dynamic release of aroma compounds under simulated oral conditions (temperature and shearing). Two custard desserts, with two levels of texture but the same composition, flavoured with four aroma compounds, were analysed. The rheological behaviour of the custards and the release of aroma compounds (SPME analysis) were simultaneously followed, using a mouth simulator. The custard with the lowest texture level showed the highest kinetic release for all aroma compounds studied. With fast increase of temperature (10–25°C), the decrease in viscosity of the custards and its impact on flavour release seemed to be less important than the heat transfer inside the products and its effect on partition of aroma compounds. [Copyright &y& Elsevier]

Knowledge of the rheological properties of flour is essential for establishing baking parameters. The effect of adding different amounts of whole rye and buckwheat flours (10, 20 and 30%) on the rheological behaviour of wheat dough subjected to mixing and thermal constraints was studied using the Mixolab system. The results showed that the addition of buckwheat and rye induces significant changes in the physical properties of whole wheat flour dough. A synergetic effect was observed in both wheat/rye and wheat/buckwheat blends, in terms of peak torque (C3), minimum torque reached during cooling (C4) and torque after cooling (C5), indicating the suitability of the tested blends for bread making. [ABSTRACT FROM AUTHOR]

Compression and stirring tests were performed to investigate the rheological behaviour of wrought aluminium alloys with varying processing parameters, such as liquid fraction, strain rate, shear rate and materials. The present paper shows the results of an experimental investigation using Al2024, Al6061 and AI7075. Specimens of each aluminium alloy were characterised by their rheological behaviour during partial melting and holding in the semisolid state. The compression and stirring tests allow the apparent viscosity of the alloys to be determined as a function of the liquid fraction and shear rate. Moreover, the change of grain size and shape was examined by considering shear rate, stirring time and liquid fraction during stirring. These experimental results could be used in flow and solidification analyses and could be useful for manufacturing good rheological products by observing the microstructures according to changes in solid fraction and compression rates. [ABSTRACT FROM AUTHOR]

Copyright of Revista Fuentes, El Reventón Energético is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: The rheological properties of A357 semi-solid slurries, produced under different conditions using the SEED process, were analyzed with a novel “Rheo-Characterizer” apparatus. The TiB2 grain refiner was also added to evaluate the impact on the microstructure and the cutting force. The α-Al particles and grain size were measured under different processing conditions. The effect of the solid fraction on the resulting cutting force curve was also investigated by altering the cutting temperature. The results show that the “Rheo-Characterizer” is capable of differentiating between the microstructural morphologies and the solid fraction present in the slug. A simple theoretical model was proposed to better understand the relationship between the microstructure and the cutting behaviour of the semi-solid slurry. The model, together with an analysis of the deformation phenomena observed on the wire and the slug, roughly predicts the principal characteristics of the experimental cutting curves. [Copyright &y& Elsevier]

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Experiments are carried out on the rheological behaviour of ethylene glycol (EG) based titanate nanotubes (TNT) nanofluids containing 0.5, 1.0, 2.0, 4.0 and 8.0 wt.% TNT at 20–60 °C. The results show a very strong shear thinning behaviour of the TNT nanofluids and big influences of particle concentration and temperature on the zero shear viscosity (ZSV) and high shear viscosity (HSV), for which the conventional form of Brenner & Condiff Equation fails to predict. Theoretical analyses show that these experimentally observed phenomena can be well interpreted by the conventional colloid theory if particle shape and aggregation effects are taken into account and different relative importance of the Brownian diffusion and convection at different shear rates. It is suggested that nanofluids containing tube / rod-like nanoparticles with effective aspect ratio (r a) and effective volume fraction (φ a) can be classified into dilute nanofluids with 0 < φ a <1/r a 2, semi-dilute nanofluids with 1/r a 2 < φ a <1/r a, semi-concentrated and concentrated nanofluids with 1/ra < φ a. [Copyright &y& Elsevier]

This paper focuses on the mechanical behaviour of PP/MWCNT composites. The Young’s modulus and the rupture strain versus nanotubes content are investigated. Four grades are made: 1 wt%, 2 wt%, 4 wt%, 8 wt%. The achievement of the tensile test samples require three phases: the mixing stage, the identification of the rheological behaviour stage and the injection molding stage. In the mixing stage, one must be careful that there’s a good dispersion of the MWCNT in the polymer matrix. The rheological behaviour of the PP/MWCNT composite show that the useful injection molding parameters of the neat PP can be reinvestigated for the PP/MWCNT composites. Results of the mechanical experiments clearly show a high dependence of the Young’s modulus and the rupture strain with the CNT content. [ABSTRACT FROM AUTHOR]

The Mixolab is an instrument that can be used to characterize the rheological behavior of dough subjected to a dual mixing and temperature constraint. Different varieties of wheat (Alex, Dropia, Boema, Azimut, Apache, Josef, Capo and Renesansa), cropped in the East of Romania, were tested on the Mixolab. The changes of the Mixolab curve trend depended on the value of the particle size indexing, falling number and proteine quality. Renesansa variety is characterized by strong water absorption, while Capo and Dropia varieties are strong varieties since they are characterized by a longer development time. Apache variety is characterized by a high C2, giving indications about the good quality of the proteins. Based on C3 varieties Azimut and Apache appear to form strong hard gells, and Capo has a high C5.Taking into account the obtained results we may conclude that Mixolab is a complex device that can be used to characterize the wheat varieties. [ABSTRACT FROM AUTHOR]

Brewers' spent grain (BSG) contains high amounts of dietary fiber, which may regulate the food matrix behaviour. The study aimed to evaluate the impact of spent grain on yogurt. Different levels of BSG were substituted in yogurt fermentation and its impacts on microstructural properties including surface chemical properties and confocal microstructures were studied. The quality of the yogurt was evaluated by determining rheological behavior, syneresis, color, acidity and the amount of lactic acid bacteria (LAB) at 1, 7 and 14 days of storage. The addition of BSG shortened the fermentation time, increased the viscosity and shear stress. FTIR analysis showed that BSG intensifies the band region stretching which describes a modification in a certain functional group. Confocal laser scanning microscopy identified a disruption in the cross-link between fat-protein and yogurt matrix due to the addition of BSG. During the storage, BSG was able to maintain the flow behaviour and stability, which was shown as the change in flow behaviour and syneresis. Furthermore, BSG provided the nutrients for the survival of LAB during the storage and maintained the amount of lactic acid in yogurt during the 14 days of refrigerated storage. The substitution 5%–10% of BSG improved the quality of yogurt as the maximum quality such as acidity, rheological behavior and LAB growth. Even though 15%–20% of BSG generated the same level of acidity and LAB, and had the lowest syneresis, it diminished the flow performance of the yogurt. [Display omitted] • Brewers' spent grain shortened the fermentation process of yogurt. • Brewers' spent grain maintained the flow behavior of yogurt. • Brewers' spent grain allowed LAB survival during the storage. • Brewers' spent grain reduced the syneresis of the yogurt. [ABSTRACT FROM AUTHOR]

Microalgae are a promising and sustainable ingredient for functional food development, due to their rich nutritional and health-promoting effects. Moreover, microalgae generally contain large amounts of structural biopolymers such as proteins and polysaccharides, which might display interesting technological features and rheological properties. This study aims at unravelling Phaeodactylum tricornutum extracts (PTE) potential role as structuring agents for food applications. Distilled water and a mixture of water/ethanol (75/25, v v−1) were used as solvents. Extracts' physicochemical properties were analysed regarding protein folding, molecular weight distribution, polymer interactions, and their main functional groups. PTE thermal properties, rheological behaviour, and emulsifying capacities were also evaluated. PTE showed different gelling mechanisms, with 40 °C aqueous purified extracts reporting the strongest gel character. Moreover, 80 °C ethanolic purified extracts showed the greatest emulsifying potential, with an initial emulsification index (EI) of around 90%. This EI decreased to 60% after 10 days, but remained constant for the following 15 days, showing an interesting emulsion stability. Overall, these findings suggest that PTE have a great potential for further application as thickening or emulsifier food ingredients. This diatom revealed to be a valuable source of structurally diverse, technologically active compounds. [Display omitted] • P. tricornutum is an interesting source of carbohydrates, proteins, and minerals. • Different polymer interactions result in distinct technologic features. • 40 °C aqueous purified extracts evidenced the strongest gel character. • 80 °C ethanolic purified extracts showed the greatest emulsifier potential. • Phaeodactylum tricornutum extracts may be tuned for different food formulations. [ABSTRACT FROM AUTHOR]

Functional changes of hen’s egg yolk rheological behaviour as a result of processing (pasteurisation, freeze-drying) and modifying its phospholipids using phospholipase A1 (PLA1) and phospholipase A2 (PLA2) were studied. It could be shown how fermentation with phospholipases affects the different steps of heat-induced gelation of egg yolk. As a consequence of fermentation of native yolk with 0.1% PLA1, the first viscosity maximum was shifted from 79 to 97 °C. In fermented pasteurised yolk, the homogenous gel-like consistency from the first viscosity maximum was even stabilised up to 100 °C. The second viscosity ascent, which indicates solid gel structures (caused by aggregation of denatured proteins), was prevented entirely. In contrast to pancreatic PLA2, fermentation of egg yolk with microbial PLA1 resulted in a hydrolysis of approximately 78% of phosphatidylethanolamine and a significant change in flow behaviour (of yolk solutions). [ABSTRACT FROM AUTHOR]

Most of the previous research on recycled concrete aggregates (RCA) has focused on coarse RCA (CRCA), while much less has been accomplished on the use of fine RCA particles (FRCA). Furthermore, most RCA research disregards its unique microstructure, and thus the inferior performance of concrete incorporating RCA is often reported in the fresh and hardened states. To improve the overall behaviour of RCA concrete advanced mix design techniques such as equivalent volume (EV) or particle packing models (PPMs) may be used. However, the efficiency of these procedures to proportion eco-efficient FRCA concrete still requires further investigation. This work evaluates the overall fresh (i.e., slump and rheological characterization) and hardened states (i.e., non-destructive tests, compressive strength and microscopy) performance of sustainable FRCA mixtures proportioned through distinct techniques (i.e., direct replacement, EV and PPMs) and incorporating different types of aggregates (i.e., natural and manufactured sand) and manufacturing processes (i.e., crusher fines and fully ground). Results demonstrate that the aggregate type and crushing process may influence the FRCA particles' features. Yet, the use of advanced mix design techniques, particularly PPMs, may provide FRCA mixes with quite suitable performance in the fresh (i.e., 49% lower yield stress) and hardened states (i.e., 53% higher compressive strength) along with a low carbon footprint. [ABSTRACT FROM AUTHOR]

• Effect of GO on thermo-physical property of MO lubricant was studied and modelled. • Nano lubricants show Non – Newtonian shear thinning behaviour at all temperatures. • Thermal conductivity and dynamic viscosity enhanced to 70% and 55% for 0.75 vol%. • Maximum MOD of proposed correlations for both properties achieves 0.32% and 2.33%. • ANN outperforms correlation for both properties with R2 of 0.99998 and 0.9988. Suspension of nano additives in lubricants enhances its thermo-physical behaviour and prolongs the compressor durability in eco-friendly refrigeration systems. Therefore, this study investigates the influence of graphene oxide (GO) nano platelet concentration range of 0.05 – 0.75 vol%, temperature range of 30 – 90 °C and shear rate range of 5.48 s−1 to 190 s−1 on the thermal and rheological behaviour of mineral oil lubricant. Field Emission Scanning Electron Microscopy (FESEM) analysis confirms the platelet structure of GO with a maximum sheet thickness of 5 nm. FT-IR result confirms the pure physical interaction of GO with lubricant. Thermal conductivity and dynamic viscosity of nano lubricants ascended with increasing GO concentration and descended with increasing temperature. The maximum thermal conductivity enhancement of 70% was achieved for the nano lubricant with 0.75 vol% at 30 °C with respect to pure oil. Non - Newtonian shear thinning behaviour was possessed by both pure and nano lubricants at all temperatures. The Artificial Neural Networking (ANN) and mathematical correlation were developed to predict the thermo physical properties of nano lubricants. The maximum R-square value of 0.99998 and 0.9988 was achieved for ANN models of thermal conductivity ratio and relative viscosity of nano lubricants. The ANN model outperforms mathematical correlation by achieving maximum R-square and minimum mean square error (MSE). [ABSTRACT FROM AUTHOR]

The paper presents the addition influence of some forest fruits aqueous extracts (introduced "as such" or like oil in water emulsions) about the stability of food solid emulsions. The estimation of rheological properties of these emulsions as well as for the control sample was realized under controlled temperature, after 72 hours from preparation. From the dependence between the shear stress t and the shear rate ? it was established that the emulsions present non-Newtonian behavior with initial shear stress t0 and a very good stability. [ABSTRACT FROM AUTHOR]

In this paper, the crystallization behavior, thermal degradation properties, rheological behavior and the spinnability of poly( β-hydroxybutyrate- co-hydroxyvalerate) (PHBV) fiber were studied. Experimental results indicated that the spherulite growth rate of PHBV was very slow and its size was very large. PHBV began to degrade above 170°C. The flowing curve indicated that the processing temperature and the residential time had important effects on PHBV melts. When the equipment of melting spinning was improved and processing conditions were strictly controlled, the mechanical properties of the PHBV filament can comply with the requirements of the American Pharmacopoeia. [ABSTRACT FROM AUTHOR]

Abstract: Effects of bran concentration, bran particle size distribution, and enzyme addition – fungal phytase, fungal alpha-amylase – on the mixing and fermentative behaviour of wheat dough and on the amount of phytic acid remaining in bread have been investigated using a factorial design of samples 24. Bran concentration and bran particle size significantly affected all Farinograph parameters, whereas enzyme effects were particularly observed on both the water absorption of the flour and the parameters characterizing the overmixing. Water absorption was maximized in doughs with higher fine bran addition and/or in doughs with no enzymes, and was minimized in blends containing coarse added bran and alpha-amylase and/or alpha-amylase and phytase. alpha-Amylase addition had a significant positive effect on dough development and gassing power parameters during proofing. At low bran addition, phytate hydrolysis takes place to a greater extent than at high bran addition levels. Combination of bran with amylolytic and phytate-degrading enzymes could be advisable for overcoming the detrimental effect of bran on the mineral availability (phytase) or on the technological performance of doughs (alpha-amylase). [Copyright &y& Elsevier]

Abstract: The workability, the strength and the toughness are the significant factors for self-compacting-high performance concrete (SCHPC). The workability is a significant precondition for application of the Fibre Reinforced SCHPC. This paper presents research results on the workability of Monofibre and Fibre Cocktail (hybrid steel-polypropylene fibre) Reinforced SCHPC. Lots of mixtures made with steel fibres, PP-fibres and fibre cocktail of various dosages have been investigated. The mixtures were tested using various new methods for evaluating the flowability, filling ability and segregation risk of the fresh mortar/concrete. Based on the results of the workability, the suitable fibre types (steel fibres, PP-fibres and fibre cocktail) and the upper level of the fibre dosages for Fibre Reinforced SCHPC have been selected for study of the mechanical behaviour and the failure patterns in the next phase. [Copyright &y& Elsevier]

Abstract: The influence of temperature was pointed out on the release of aroma compounds from a model dairy dessert and on its rheological behaviour. The recipe chosen for inter-laboratory studies within the programme of COST Action 921 was tested. The custards were flavoured with three aroma compounds belonging to strawberry note. The partition coefficients of three compounds (ethyl butyrate, ethyl hexanoate, cis-3-hexenol) were determined at three temperatures (12°C: tasting temperature of refrigerated dairy products, 20°C: room temperature, and 37°C: mouth temperature). Two textures of the custards were obtained using kappa- and iota-carrageenan. Penetrometry tests characterized the rheological properties of the custards. Whatever the temperature, aroma compounds had a greater affinity for the custard rather than for the water. Moreover, the temperature modified the rigidity character of the custard, which should affect the repartition of the aroma compounds between vapour phase and custards. [Copyright &y& Elsevier]

The paper presents some experimental works that allow concluding that a new effect of the ultrasounds, “ultrasonic thermo-pellicle effect”, may be accepted. It was identified during the application of the ultrasonic energy to melted polymers in flowing state. The modifications of the properties at the interface between the melted material and the metallic die could postpone, due to ultrasonic activation, the beginning of the “stick-slip” phenomenon allowing the increase of the productivity and the product quality and the flow of the thermoplastic material through the die of the extrusion head. The concept could be extended for high dense fluids as revealed in the last part of the paper where some original application are proposed by the authors. [ABSTRACT FROM AUTHOR]

Abstract: Titanate nanotubes of an aspect ratio of ~10 are synthesized, characterised and dispersed in water to form stable nanofluids containing 0.5, 1.0 and 2.5 wt.% of the nanotubes. Experiments are then carried out to investigate the effective thermal conductivity, rheological behaviour and forced convective heat transfer of the nanofluids. The results show a small thermal conductivity enhancement of ~3% at 25 °C and ~5% at 40 °C for the 2.5 wt.% nanofluid. The nanofluids are found to be non-Newtonian with obvious shear thinning behaviour with the shear viscosity decreasing with increasing shear rate at low shear rates. The shear viscosity approaches constant at a shear rate higher than ~100–1000 s−1 depending nanoparticle concentration. The high shear viscosity is found to be much higher than that predicted by the conventional viscosity models for dilute suspensions. Despite the small thermal conduction enhancement, an excellent enhancement is observed on the convective heat transfer coefficient, which is much higher than that of the thermal conductivity enhancement. In comparison with nanofluids containing spherical titania nanoparticles under similar conditions, the enhancement of both thermal conductivity and convective heat transfer coefficient of the titanate nanotube nanofluids is considerably higher indicating the important role of particle shape in the heat transfer enhancement. Possible mechanisms are also proposed for the observed enhancement of the convective heat transfer coefficient. [Copyright &y& Elsevier]

The determination of the proper rheological behaviour of the polymer melt within micro structured geometry is vital for accurately simulating the micro moulding. The paucity of suitable equipments is one of main hurdles in the investigation of micro melt rheology. In the present study, a measurement system for the melt viscosity of low and high density polyethylene polymer melts flowing through micro-channels was established. The capillary flow model with Rabinowitsch correction was used in the calculations of the viscosity based on the measured pressure drop and volumetric flow rate. The effect of the morphology structure on the viscosity characteristics for both the LDPE and HDPE resins within micro-channels was investigated and discussed. It was found that the measured viscosity values for LDPE and HDPE in the test ranges are significantly lower (about 40 56% and 22 29% for LDPE and HDPE, respectively, flowing through a channel size of 150μm) than those obtained with a traditional capillary rheometer. Moreover, both the percentage reduction in the viscosity value and the ratio of the slip velocity to the mean velocity increase as the micro-channel size decreases. It can be observed that the rheological behaviours of the HDPE and LDPE resins in microscopic scale are different from those in macroscopic scale as a result of the wall slip effect. It also revealed that the wall slip occurs more easily for the LDPE resin within micro channels than HDPE resin due to enlarged effect of morphology structure. [ABSTRACT FROM AUTHOR]

Abstract: Two algal polysaccharides: alginate and agar and one polysaccharide from fruit, pectin, have been used as food additives in relation to their structure and their rheological behavior, stability and interactions, to generate firm pellets to be employed in crayfish aquaculture. Three diets containing the same amount of nutrients (protein, lipid and carbohydrate) mixed with each of the three different polysaccharides were tested on male freshwater crayfish Cherax albidus growth. The aims of this study were to examine the effect of alginate, agar and pectin, on pellet stability in water, and on crayfish growth. The kinetics of water absorption and solute leaching of pellets were measured by immersing quadruplicate samples of the diets in water for 0.5, 2, 4 and 8 h. After the required immersion time, the samples were recovered, freeze-dried for 24 h and re-weighed. Recovered liquid was analyzed by Low Angle Laser Light Scattering Technique, which allowed the monitoring of the released particles in water during immersion. At the same time, the crayfish feeding response to firm pellets was monitored in feeding behavior and growth experiments. Our results show that pellets had good water stability, were preferred by crayfish and the presence of polysaccharides positively affected crayfish growth. Indeed, animals fed pellets showed a higher percentage of growth when compared to animals fed a fresh diet. In particular, pectin gave the best results, showing better water stability than alginate and agar and causing the best growth performance. Pellets are relatively low cost and easy to make and they may represent an advantage for those who want to farm crayfish under intensive conditions. [Copyright &y& Elsevier]

Abstract: Systematic experiments have been carried out on the thermal and rheological behaviour of the ionic liquid, 1-butyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}imide, [C4mim][NTf2], and, for the first time, on the forced convective heat transfer of an ionic liquid under the laminar flow conditions. The results show that the thermal conductivity of the ionic liquid is ∼0.13Wm−1 K−1, which is almost independent of temperature between 25 and 40°C. Rheological measurements show that the [C4mim][NTf2] liquid is a Newtonian fluid with its shear viscosity decreasing with increasing temperature according to the exponential law over a temperature range of 20–90°C. The convective heat transfer experiments demonstrate that the thermal entrance length of the ionic liquid is very large due to its high viscosity and low thermal conductivity. The convective heat transfer coefficient is observed to be much lower than that of distilled water under the same conditions. The convective heat transfer data are also found to fit well to the convectional Shah’s equation under the conditions of this work. [Copyright &y& Elsevier]

Abstract: There is a growing need for research into new skin- and environment-friendly surfactants. This paper focuses on a natural surfactant of an alkylpolyglucoside type, which can form both thermotropic and lyotropic liquid-crystalline phases. The aim of this study was to relate some physicochemical properties (characterised by polarisation and transmission electron microscopy, thermal analysis and rheology) of the three formulations based on cetearyl glucoside and cetearyl alcohol, to the results of in vitro and in vivo bioavailability of hydrocortisone (HC). The three formulations contained oils of different polarity (medium chain triglycerides: MG, isopropyl myristate: IPM and light liquid paraffin: LP), respectively. In vitro permeation was followed through the artificial skin constructs (ASC), while the parameters measured in vivo were erythema index: EI (using instrumental human skin blanching assay), transepidermal water loss (TEWL) and stratum corneum hydration (SCH). The vehicles based on cetearyl glucoside and cetearyl alcohol showed a complex colloidal structure of lamellar liquid-crystalline and lamellar gel-crystalline type, depending on oil polarity. Rheological profile of the vehicle was directly related to the in vitro profile of the HC permeation. In vivo results suggested that the vehicle with MG retarded the HC permeation, whereas less polar IPM and non-polar LP enhanced it. It is suggested that the enhancement is achieved either by a direct interaction with lipid lamellae of the SC or indirectly by improving skin hydration. There were no adverse effects during in vivo study, which indicates a good safety profile of this alkylpolyglucoside surfactant. [Copyright &y& Elsevier]