Maximum Solid Content Research Articles

Modelling the effect of mortar constituents on rheological properties

AbstractConcrete is a widely used construction material whose potential has not yet been fully exploited due to the lack of knowledge about its rheological behaviour. The mix composition is assumed to play a key role in controlling the rheological properties of concrete. Due to the extremely high proportion of finer particles in concrete, the investigation of the rheological properties of the mortar and paste phases is of major importance in understanding the rheological behaviour of concrete. Therefore, this paper systematically investigates the impact of water‐to‐cement ratio, sand content, and maximum sand size on the rheology of flowable mortars. It also explores the applicability of existing models for modeling these mortars.The results, presented as a rheograph, reveal that a reduction of the w/c ratio and an increase in the sand solid content in the mortar leads to an increase in the rheological properties plastic viscosity and yield stress. Also, the addition of coarser sand in mortar compositions induces an increase in the maximum solid content and consequently a decrease in plastic viscosity. In addition, it shows that the Krieger‐Dougherty and Liu models are appropriate enough for modelling polydisperse suspensions.

The impact of glycerol monostearate's similarity to fats and fatty acid composition of fats on fat crystallization, destabilization, and texture properties of ice cream.

Fat significantly affects the properties of ice cream. Prior studies have investigated the correlation between fat crystallization, fat destabilization, and ice cream quality. However, the role of fatty acid composition, the similarity between fat and emulsifier in these characteristics, and their impact on final product quality remains unclear. To investigate the influence of the fatty acid composition of fats, as well as their similarity to glycerol monostearate (GMS), on fat crystallization and destabilization during the aging and freezing stages, ice creams were formulated using a combination of two types of fats (coconut oil and palm olein) in five different ratios. In oil phases, decreased saturation of fatty acids (from 93.38% to 46.69%) and increased similarity to GMS (from 11.96% to 46.01%) caused a reduction in the maximum solid fat content. Moreover, the rise in unsaturated long-chain fatty acids (from 34.61% to 99.57%) and similarity to GMS enhanced the formation of rare and coarse fat crystals, leading to a sparse crystalline network. This, in turn, reduced the crystallization rate and the stiffness of the fat in emulsions. Assuming consistent overrun across all ice creams, the enhanced interactions between fat globules in ice cream improved its hardness, melting properties, and shrinkage. The crystalline properties of fat in emulsions were influenced by oil phases, impacting fat destabilization and ultimately enhancing the quality of ice cream. The present study offers valuable insights for the optimization of fat and monoglyceride fatty acid ester selection, with the potential to improve ice cream quality. © 2023 Society of Chemical Industry.

Additive manufacturing of Al2O3 ceramic core with applicable microstructure and mechanical properties via digital light processing of high solid loading slurry

Ceramic cores are essential intermediate mediums in casting superalloy hollow turbine blades. The developing of additive manufacturing (AM) technology provides a new approach for the preparation of ceramic cores with complex structure. In this study, alumina oxide (Al2O3) ceramic cores with fine complex geometric shapes were fabricated by digital light processing (DLP) in high resolution. The maximum solid content of 70 vol% of ceramic slurry was adopted in the printing process, which is important for the regulation of deformations and mechanical properties. The effects of the printing parameters, including exposure intensity, printing layer thickness and sintering temperature on the microstructures and mechanical properties of printed samples were investigated. The decrease of residual stress and similar shrinkage in X, Y, and Z directions could be obtained by adjusting the printing parameters, which are crucial to prepare complex ceramic cores with high quality. Besides, the flexure strength and open porosity of ceramic cores reached 34.84 MPa and 26.94%, respectively, which were supposed to meet the requirement of ceramic cores for the fabrication of superalloy blades.

Effect of Hemicellulose Molecular Weight on Bonding Properties in Biobased Wood Adhesives

Today, the most commonly used adhesives in the wood industry are fossil-based, but the search for new, renewable and less hazardous, resources for adhesives is intensifying. Hemicelluloses show promising bonding performance when used as a component in wood adhesives. Since batch-to-batch variations can affect the use of hemicelluloses in a large-scale production, we have investigated the effect of hemicellulose molecular weight on important adhesive properties, such as viscosity and bond strength, by using locust bean gum as a hemicellulose model and varying the molecular weight through hydrolysis. Results showed that there is a nonlinear proportionality between bond strength and molecular weight. In the molecular weight range used in the study, 70–1460 kDa, anoptimum in the adhesive performance was achieved with intermediate molecular weights, 320 and 530 kDa, especially when considering applicability and bond strength. Adhesives with lower molecular weights, 70 and 150 kDa, did not exhibit sufficient cohesive strength; therefore, the bond strength was lower. The adhesive with higher molecular weight, 1460 kDa, was difficult to apply, especially since its maximum solid content was very low, 5 wt %.

Stereolithographic additive manufacturing of Luneburg lens using Al2O3-based low sintering temperature ceramics for 5G MIMO antenna

In this paper, we provided a manufacturing method for low-sintering-temperature radio frequency (RF) devices by stereolithographic (SLA) printing. The effect of ceramic powder percentage on rheological properties, curing behavior, sintering properties, microstructure, and dielectric properties was discussed. With the proportion of ceramic powder ranging from 60 wt% to 75 wt%, the viscosity of slurries declined, the sintering shrinkage rate varied from 21.61% to 15.83%, the dielectric constant raised from 5.22 to 6.64, and the dielectric loss initially reached the optimum value of 0.0024 and then deteriorated to 0.0035. The maximum solid content of slurries was 75 wt%, and the printable viscosity should be below 7.33 Pa·s. At the mass ratio of 65:35, the samples sintered at 850 °C showed good properties: a density of 3.0135 g·cm−3, a dielectric constant of 5.56, a low dielectric loss of 2.4 × 10−3, and τf = −32.76 ppm/°C. The printed Luneburg lens showed a gain enhancement of over 5 dB, by using a 10 dBi standard gain horn antenna as a feed source. Thus, this research established a foundation for the fabrication of ceramic RF devices with high-performance, complex structures, and low sintering temperature via SLA printing.

Effect of process parameters of mashing on consumer properties and processability of polymalt extracts production process

The development of the technology of viscous polymalt extracts using bare-grained oats will provide the population with a functional food ingredient and products with specified consumer properties. Existing techniques for the production of extracts did not affect the study of temperature conditions and the duration of the process at the mashing stage, using bare-grained oats in its composition. Crops of Belarusian breeding were used as raw materials: barley (H. vulgare), bare-grained oats (A. sativa), wheat (Tr. aestivum) grain. Optimization of parameters in the production of polymalt wort based on barley, oat and wheat malt was carried out by regression analysis and weight coefficients. Dependencies of physico-chemical indices of oat-malt and polymalt worts on temperature and duration of mashing are established. These dependencies predict content of dry substances, maltose, amine nitrogen, protein and acidity in the process of production of worts. Optimal technological parameters were selected at the stage of barley-wheat-oat polymalt wort mashing, which made it possible to increase the dry substances by 12.5%, maltose – by 21.3%, protein – by 16.2% and filtration rate – by 25.0%. The maximum solid content 14.4%, maltose 11.4 g·(100·сm-3)-1, protein 1.22%, in polymalt wort achieved under the following modes: (3 ±1)°C for 30 minutes, (44±1)°C for 50 minutes, (53±1)°C for 60 minutes, (63±1)°C for 50 minutes, (72±1)°C for 20 minutes and (78±1)°C for 60 minutes.

Conversion Enhancement of Vinyl Acetate Monomer to Polyvinyl Acetate Emulsion through Emulsion Polymerization Method

Synthesis of Polyvinyl Acetate (PVAc) through the conversion of Vinyl Acetate Monomer (VAM) was carried out by emulsion polymerization method assisted by thermal initiator Ammonium persulfate (APS) under reaction temperature was kept at 70 °C – 80 °C with 5 hours of reaction time and agitation speed at 300 rpm. The polymerization reaction was running used batch process technique where is all components were mixed all together simultaneously. A set of polymerization reactions was conducted when the absence of surfactant and cationic and amphoteric surfactant presence. The monomer chain's double bond was found at 1645 cm-1 was measured by FTIR Spectrophotometer did not disappear after polymerization reaction was utterly done. The spectrum FTIR of Polyvinyl acetate did not explicitly found at 1644 cm-1. During the reaction, characterization was conducted by measuring the solid content value where the maximum solid content was achieved was 6,1 % when using Amphoteric surfactant while the lowest solid content was obtained when the absence of surfactant. Other parameters were conducted to observe the acidity value by pH Meter.

A Novel Procedure for Performance Assessment of Paste Thickeners

ABSTRACT High stability and low settling rate of phosphate fines in water suspensions encountered the dry area-located mines with serious environmental and technical challenges. The best suggestion for these mines is paste thickener installation for dewatering. In this research, the novel procedure has been proposed for evaluating the potential of paste thickeners in dewatering mining tailings. The case study is Esfordi phosphate complex (Iran). Initially, the selection criteria of a proper flocculant (environmental effects, price, particle settling rate, turbidity of overflow water, and underflow water content) were evaluated for current consuming flocculant (A-27) and 12 other ionic and nonionic flocculants. Then, flocculation performance was ranked based on the type and concentration, applying multiple criteria decision-making (MCDM) techniques of ORESTE, MAPPAC, and ELECTRE. Subsequently, the pilot-scale tests were performed for the selected flocculants and the operational conditions were evaluated for the maximum underflow solid content of 70 wt.%. The results of the present research showed that installation and application of this type of thickener could be effective for the case study.

Conching chocolate is a prototypical transition from frictionally jammed solid to flowable suspension with maximal solid content

The mixing of a powder of 10- to 50-μm primary particles into a liquid to form a dispersion with the highest possible solid content is a common industrial operation. Building on recent advances in the rheology of such "granular dispersions," we study a paradigmatic example of such powder incorporation: the conching of chocolate, in which a homogeneous, flowing suspension is prepared from an inhomogeneous mixture of particulates, triglyceride oil, and dispersants. Studying the rheology of a simplified formulation, we find that the input of mechanical energy and staged addition of surfactants combine to effect a considerable shift in the jamming volume fraction of the system, thus increasing the maximum flowable solid content. We discuss the possible microscopic origins of this shift, and suggest that chocolate conching exemplifies a ubiquitous class of powder-liquid mixing.

Semi-continuous mono-digestion of OFMSW and Co-digestion of OFMSW with beech sawdust: Assessment of the maximum operational total solid content

In this study, mono-digestion of the organic fraction of municipal solid waste (OFMSW) and co-digestion of OFMSW with beech sawdust, simulating green waste, were used to investigate the maximum operational total solid (TS) content in semi-continuous high-solids anaerobic digestion (HS-AD). To alleviate substrate overloading in HS-AD, the effluent mass was relatively reduced compared to the influent mass, extending the mass retention time. To this aim, the reactor mass was daily evaluated, permitting to assess the reactor content removal by biogas production. During mono-digestion of OFMSW, the NH3 inhibition and the rapid TS removal prevented to maintain HS-AD conditions (i.e. TS ≥ 10%), without exacerbating the risk of reactor acidification. In contrast, the inclusion of sawdust in OFMSW permitted to operate HS-AD up to 30% TS, before acidification occurred. Therefore, including a lignocellulosic substrate in OFMSW can prevent acidification and stabilize HS-AD at very high TS contents (i.e. 20–30%).

Surface Modification of SiC Powder with Sodium Humate: Adsorption Kinetics, Equilibrium, and Mechanism.

Highly dispersible SiC powder was prepared using sodium humate as a modifier. The results showed that the ζ-potential absolute value of the modified SiC powder increased from 13.1 to 38.7 mV when the adsorption capacity of sodium humate on the SiC surface was 2.368 mg/g. The slurry with a maximum solid content of 65 vol % was obtained using the modified SiC powder, and the minimum viscosity value was 0.322 Pa s at a solid content of 50 vol %. The adsorption kinetics equation of sodium humate on the SiC surface is t/ q t = 0.6253 t + 11.0472, which is in accordance with the pseudo-second-order kinetics model. In addition, the isotherm equation, ln qe = 0.461 ln Ce - 0.334, agrees with the Freundlich model. The adsorption energy of sodium humate on the SiC surface was 0.8280 kJ/mol, indicating that the adsorption type was physical adsorption.

High solid content poly(butyl acrylate)/poly(methyl methacrylate) core/shell nanosized spheres synthesised by microemulsion polymerisation

Core–shell nanosized polymer particles with poly(butyl acrylate) (PBA) as core and poly(methyl methacrylate) (PMMA) as shell were synthesised via a semi-continuous two-stage microemulsion polymerisation. A series of experiments were conducted to investigate the maximum solid content of the microemulsion under different surfactant/monomer ratios, and it was found that the maximum solid content could reach around 43.73% with minimum surfactant/monomer at only 5.25 wt%. The particle samples were characterised by proton nuclear magnetic resonance (1H-NMR), scanning electron microscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. 1H-NMR and TEM results revealed that PBA/PMMA core/shell composite latexes were synthesised successfully by microemulsion polymerisation. DLS studies indicated that an optimal dosage of surfactant (1.29 wt% of the total amount of monomers) was found to synthesise particles with desired core–shell structure, which was consistent with the theoretical calculation. The size of nanoparticles increased with the increase in the amount of core monomer, showing an inverse relationship with surfactants.

Otimização reológica de suspensões aquosas de óxido de ferro (III)

In this work the dispersion of iron oxide III particles in aqueous media was studied. To achieve the maximum solid content zeta potential measurements were carried as a function of pH. The influences of two different types of polyacrylates as dispersants were investigated. Suspensions were produced by varying solids concentration up to 30 vol.%. The results showed a strong influence of pH on the size distribution of the particles in suspension. The most efficient dispersant towards particle dispersion was sodium polyacrylate. The maximum solid content in the suspension was optimized to 25 vol % with density values higher than 35% theoretical density with 2 wt.% polyacrylate.

Concentration factor and rheology of aqueous titanium dioxide dispersions

The rheological properties of aqueous titanium dioxide dispersions have been studied by rotational viscometry. It has been established that the studied disperse systems are highly structured, and their degree of structuring dramatically increases with the volume fraction φ of the solid phase. At solid phase contents φ ≥ 0.164, the breakage of the disperse structure is accompanied by the appearance of local discontinuities and an abnormal dependence of viscosity on shear stress. The results obtained have been analyzed in terms of the Uriev theory of aggregated systems. The radii of aggregates and maximum solid phase content φm that corresponds to the formation of a continuous disperse structure under the conditions of dynamic impact have been calculated.

Incorporating different vegetable oils into an aqueous dispersion of hybrid organic nanoparticles

Different vegetable oils including soy oil, high-oleic sunflower oil, corn oil, castor oil (CO), rapeseed oil, and hydrogenated CO were added to the imidization reaction of poly(styrene–maleic anhydride) or SMA, with ammonium hydroxide in aqueous medium. The oils favorably reduce viscosity during ammonolysis of the anhydride moieties and increase the maximum solid content of the dispersed imidized SMA to at least 50 wt%, compared to a maximum of 35 wt% for pure imidized SMA. The viscosity of imidized SMA with polyunsaturated oils was generally larger than for monosaturated oils, but it was highest for COs due to high contents of hydroxyl groups. Depending on the oil reactivity, homogeneous or core–shell nanoparticles with 20–60 nm diameters formed. The interactions of oil and organic phase were studied by Fourier-transform infrared spectroscopy, indicating qualitative variances between different oils, the fraction imidized SMA and remaining fraction of ammonolyzed SMA without leakage of oil upon diluting the dispersion and precipitation at low pH. A quantitative analysis with calculation of imide contents, amounts of reacted oil and chemical interactions was made by Fourier-transform-Raman spectroscopy suggesting that most interactions take place around the unsaturated oil moieties and ammonolyzed anhydride.

Molecular weight control of PS spheres using soap free and RITP-soap free emulsion polymerization

The reversible iodine transfer polymerization (RITP) of styrene in the absence of light was carried out using potassium persulfate (KPS) under argon atmosphere at 80 °C for 7 h and the properties of the polymers were compared to those obtained from the soap-free emulsion polymerization (SFEP). The variables were the concentration of KPS and iodine, molar ratios between KPS and iodine, reaction temperatures, and monomer contents. The results showed that the conversion retarded and reached from 99.5% to 82%, the particle size dramatically increased from 0.335 to 1.37 μm, the molecular weight decreased from 183,000 to 66,000 g/mol, and the polydispersity index (PDI) increased from 2.7 to 3.8 for the presence of 2 wt% of KPS and iodine content between 0 and 0.228 mmol, respectively, implying that the molecular weight was controlled and that the particle stability was reduced with iodine as usual. For the effects of the solid content on particle properties, the monomer conversion and the particle size increased, but the molecular weight and PDI decreased with the increased KPS content and [KPS]/[I2] ratio. The highest content was 30 wt% and this was less than that in the presence of sodium dodecyl sulfate (SDS) in the RITP-emulsion and in the absence of SDS in the SFEP. Thus, the use of an emulsifier in the RITP or SFEP was one of the important factors for obtaining the maximum solid content needed for industrial applications.

Characterization of the Stearin Obtained by Thermal Fractionation of Anhydrous Milk Fat

Thermal fractionation of anhydrous milk fat with high initial content of low molecular weight TAGs was performed based on a 2 2 factorial experimental design with three central and two axial points. The independent variables were the crystallization temperature and the cooling rate. A 2.0 L agitated glass reactor was used and the rotation was kept at 20 rpm. The filtration was performed under vacuum (500 mmHg), using a 14 μm average pore diameter filter paper. Curves of isothermal crystallization of the stearin fraction showed that increasing the crystallization temperature, increases the induction period and decreases the maximum solid content of stearin. An increase of the crystallization temperature resulted in an increase in solid fat content. All runs achieved an efficient fractionation using a single separation step and stearin with defined characteristics can be obtained adapting the process conditions.

Synthesis and characterization of imidized poly(styrene‐maleic anhydride) nanoparticles in stable aqueous dispersion

AbstractOrganic nanoparticles are synthesized by partial imidization of high‐molecular weight styrene(maleic‐anhydride) with 26 to 34 mol% maleic anhydride, in aqueous environment and presence of ammonium hydroxide. The nanoparticle dispersions have a maximum solid content of 35 wt% and good stability that critically depends on the ratio of imidized and ammonolyzed maleic anhydride moieties. The deprotonated residual maleic anhydride moieties provide dispersion stability at pH > 4, while protonation at pH < 4 causes nanoparticle sedimentation. After presentation of the synthesis conditions, the imidization reaction is characterized by FT‐IR and Raman spectroscopy, followed by thermal analysis (TGA, DSC), and morphological characterization (DLS, SEM, TEM, AFM). The reaction conditions were optimized by physical characterization of various dispersions, and finally nanoparticles could be obtained with a maximum degree of imidization of 77% in dispersed conditions, or 90 to 95% after drying that are favorable for coating applications. Copyright © 2010 John Wiley & Sons, Ltd.

Modifications of paper and paperboard surfaces with a nanostructured polymer coating

Organic nanoparticles synthesized by imidization of styrene-maleic anhydride copolymers are deposited as a top-coating onto paper and paperboard substrates from a stable aqueous dispersion with maximum solid content of 35wt.%. The morphology, physical characteristics and chemical surface properties of the coatings are discussed in this paper, using scanning electron microscopy, atomic force microscopy, contact angle measurements and Raman spectroscopy. Due to the high glass transition temperature of the polymer nanoparticles, a unique micro- to nanoscale structured coating is formed that favourably improves the gloss, printing properties (ink-jet printing test and off-set printing test), surface hydrophobicity (maximum water contact angle 140°) and water repellence (reduction of Cobb-values). The interaction of the nanoparticle coatings with the cellulosic paper web results in improvement of the mechanical paper strength and is attributed to hydrogen-bonding between the nanoparticles and the cellulosic fibers.

Influence of chemical interesterification on thermal behavior, microstructure, polymorphism and crystallization properties of canola oil and fully hydrogenated cottonseed oil blends

This work evaluated chemical interesterification of canola oil (CaO) and fully hydrogenated cottonseed oil (FHCSO) blends, with 20%, 25%, 30%, 35% and 40% (w/w) FHCSO content. Interesterification produced reduction of trisaturated and increase in monounsaturated and diunsaturated triacylglycerols contents, which caused important changes in temperatures and enthalpies associated with the crystallization and melting thermograms. It was verified reduction in medium crystal diameter in all blends, in addition crystal morphology modification. Crystallization kinetics revealed that crystal formation induction period and maximum solid fat content were altered according to FHCSO content in original blends and as a result of random rearrangement. Changes in Avrami constant (k) and exponent (n) indicated, respectively, that interesterification decreased crystallization rates and altered crystalline morphology. However, X-ray diffraction analyses showed randomization did not change the original crystalline polymorphism. The original and interesterified blends had significant predominance of b 0 polymorph, which is interesting for several food applications.