Rheological Studies Research Articles

Green synthesis of stretchable ethyl cellulose film plasticized with transesterified sunflower oil

Sustainability and environmental consciousness drive research toward biomaterials and green synthesis. Traditional plasticizers derived from non-renewable sources have raised concerns due to their adverse impact on the environment and human health. As a result, there is a growing interest in replacing these traditional plasticizers with inexpensive naturally derived alternatives. One such promising compound that has gained considerable attention is vegetable oil. In this study, we investigated the feasibility of using transesterified sunflower oil as a plasticizer for ethyl cellulose (EC), a widely used hydrophobic biopolymer. The transesterification reaction, accelerated by the catalyst NaOH, resulted in the formation of short chemical compounds that improved the plasticity of EC films. The mechanical studies demonstrated a remarkable elongation break of approximately 94 %, setting a new record for this type of film. The plasticization process was confirmed through rheological and XRD studies, revealing a notable reduction in the elastic chain and crystallinity of the EC structure. The proposed process advances the state of the art in ethyl cellulose plasticization and stands out for its simplicity, cost-effectiveness, and environment-friendly approach. The synthesized films offer exciting possibilities for use in various applications including food packaging, transdermal drug delivery systems, and stretchable electronics.

Squeezing flow in the existence of carbon nanotubes past a Riga plate

Squeezing or squeeze flows have tremendous applications in applied fields, like engineering, biomedical sciences and rheological studies. This paper demonstrates the squeezing flow of kerosene-based nanoliquids between parallelly aligned plates, with a Riga-type fixed lower boundary. The effects of dispersing two types of copper-functionalized carbon nanotubes (CNTs), single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs) are examined. Using appropriate transformations, a self-similar ordinary differential system is derived from the governing model of partial differential equations and substantial boundary conditions. Using the homotopy analysis method (HAM) and the [Formula: see text] package, analytical and numerical estimates are obtained, respectively. For higher values of the squeezing parameter, dimensionless temperature increases, while velocity patterns are upside-down. Moreover, increments in dimensionless parameters representing Riga constituent width, modified Hartmann number, nanoparticle concentration and radiation parameter improve heat transfer rates and thermal boundary layer thickness, however, adversely affect velocity. Despite enhanced friction effects, numerical results show that the Nusselt number increases as nanoparticle loads and radiation parameters increase. This suggests that convection rates are improved over conduction rates. Excellent agreement is found between analytical and numerical evaluations. Apparently, it is noticed that MWCNTs perform better than SWCNTs.

Modulation of Methacrylated Hyaluronic Acid Hydrogels Enables Their Use as 3D Cultured Model.

Bioengineered hydrogels represent physiologically relevant platforms for cell behaviour studies in the tissue engineering and regenerative medicine fields, as well as in in vitro disease models. Hyaluronic acid (HA) is an ideal platform since it is a natural biocompatible polymer that is widely used to study cellular crosstalk, cell adhesion and cell proliferation, and is one of the major components of the extracellular matrix (ECM). We synthesised chemically modified HA with photo-crosslinkable methacrylated groups (HA-MA) in aqueous solutions and in strictly monitored pH and temperature conditions to obtain hydrogels with controlled bulk properties. The physical and chemical properties of the different HA-MA hydrogels were investigated via rheological studies, mechanical testing and scanning electron microscopy (SEM) imaging, which allowed us to determine the optimal biomechanical properties and develop a biocompatible scaffold. The morphological evolution processes and proliferation rates of glioblastoma cells (U251-MG) cultured on HA-MA surfaces were evaluated by comparing 2D structures with 3D structures, showing that the change in dimensionality impacted cell functions and interactions. The cell viability assays and evaluation of mitochondrial metabolism showed that the hydrogels did not interfere with cell survival. In addition, morphological studies provided evidence of cell-matrix interactions that promoted cell budding from the spheroids and the invasiveness in the surrounding environment.

Synthesis of novel antibacterial and biocompatible polymer nanocomposite based on polysaccharide gum hydrogels

According to recent studies on the benefits of natural polymer-based hydrogels in biomedical applications, gellan gum (GG)/acacia gum (AG) hydrogel was prepared in this study. In order to regulate the mechanical behavior of the hydrogel, graphite carbon nitride (g-C3N4) was included in the hydrogel matrix. In addition, metal oxide nanoparticles ZnCuFe2O4 were added to the composite for antibacterial activity. The prepared GG–AG hydrogel/g-C3N4/ZnCuFe2O4 nanobiocomposite was characterized by using FE-SEM, FTIR, EDX, XRD and TGA. The nanobiocomposite exhibited spherical morphology, which was related to the incorporation of the metal oxide nanoparticles. GG–AG hydrogel/g-C3N4/ZnCuFe2O4 nanobiocomposite showed 95.11%, 92.73% and 88.97% biocompatibility toward HEK293T cell lines within 24 h, 48 h and 72 h incubation, respectively, which indicates that this nanobiocomposite is completely biocompatible with healthy cells. Also, the nanobiocomposite was able to inhibit Pseudomonas aeruginosa biofilm growth on its surface up to 87%. Rheological studies showed that the nanobiocomposite has a viscoelastic structure and has a water uptake ratio of 93.2%. In comparison with other similar studies, this nanobiocomposite has exhibited superior antibacterial activity complete biocompatibility and proper mechanical properties, high swelling and water absorption capability. These results indicate that GG–AG hydrogel/g-C3N4/ZnCuFe2O4 nanocomposite can be considered as a potential candidate for biomedical applications such as tissue engineering and wound healing.

Alkyl ketene dimer modification of thermomechanical pulp promotes processability with polypropylene

AbstractAlkyl ketene dimers (AKDs) are known to efficiently react with cellulose with a dual polarity in their structure: a polar component and a nonpolar component. AKD of three different carbon chain lengths, 4, 10, and 16 carbons have been synthesized, and thermomechanical pulp (TMP) fibers were modified by them. The modification of TMP fibers with AKD resulted in an increased water contact angle, showing the presence of the AKDs on the TMP fibers and a new carbonyl peak in the IR spectra, suggesting modification of the TMP fibers with AKD groups. Calculating the Hansen solubility parameters of AKD and AKD conjugated to TMP in polypropylene (PP) indicates improved compatibility, especially of longer chain AKD and TMP AKD. The rheological studies of the composites showed that the AKD with the longest carbon chain decreases the melt viscosity of the PP‐TMP‐AKD composite, which combined with the shape and the color of the extruded composite filaments indicates improved flow properties and reduced stress build up during processing. The research findings demonstrate the ability of AKD to enhance the dispersibility and compatibility of natural fibers with PP.

Decoupling of mechanical properties and ionic conductivity in a low molecular weight polymer nanocomposites with highly connected particle aggregates

HypothesisHigh molecular weight polymer nanocomposites (PNCs) with good thermal stability and elevated mechanical strengths can serve as composite polymer electrolytes (CPEs) and thus have been considered as an alternative to conventional liquid electrolytes. However, resolving low ionic conductivity issues of CPEs arising from the low chain mobility derived from a long polymer chain remains challenging. ExperimentsHere, we introduce PNCs for use in CPEs which show 1.4 × 10−4 S/cm of ionic conductivity at room temperature with a high shear modulus of 107 Pa using a low molecular weight poly(ethylene glycol) (PEG) matrix and dopamine-modified PEG brush polymer grafted-silica nanoparticles. FindingsWe found that densely interconnected supramolecular particle networks can decouple the mechanical strength and ionic conductivity, as the Li-doped interfacial polymer layer supports a direct lithium-ion transport pathway. The extensive structural and rheological studies characterized by small-angle X-ray scattering and oscillatory rheometry experiments revealed that particle connections through interfacial polymer layers play an important role in supporting the elevated mechanical and electrochemical properties with a good thermal stability of PNCs.

Rheological and tribological behaviour of nanofluids: an experimental evaluation

Commercially available synthetic engine oils of SAE grades 5W40 were taken as base fluids for preparing nano fluids by blending 0.1% and 0.2% concentration by weight of the functionalized Cu and MoS2 nanoparticles in them. The base fluids and their blends were characterized using standard ASTM and IS testing methods for their physicochemical and tribo performance behaviours. The rheological studies were performed on a Rheometer while the tribological investigations were performed on tribo-tester. The study reveal that a small improvement in anti- friction behaviour of about 6% and 4% reported for the 0.2 wt% of Cu and MoS2 nanoparticles respectively in the tested lubricants indicate that finished products have little scope to improve anti-friction properties under the influence of already present additives, however anti-wear properties showed significant enhancement up to 20% for 0.2% MoS2 and up to 15% for 0.2% nano-Cu indicating better anti-wear properties of MoS2 and Cu nanoparticle blends. Rheological studies reveal that blending of nanoparticles has marginal influence on the rheological behaviour of the lubricants. The lubricants show shear thinning behaviour at low shear rates. However at higher shear rates, lubricants behave as Newtonian fluids.

Effect of cement kiln dust and lignosulfonate on cement paste: a rheology and hydration kinetics study

This research provides a comprehensive analysis of the influence of cement kiln dust (CKD) and lignosulfonate (LS) on the rheology and hydration kinetics of cement paste. The interaction effect, dispersion potential, and adsorption kinetics of LS on the cement/CKD paste were obtained using UV spectroscopy and zeta potential measurements. The results indicate that the addition of LS reduces the yield stress and plastic viscosity through the dispersion effect of LS, which alters the adhesion of the particles and improves the rheology of the CKD/cement paste. The competing adsorption of LS by the cement and CKD particles increased the flowability of the cement paste and a maximum was obtained due to the stable combined action of two different mechanisms of steric hindrance and electrostatic repulsion by LS. The X-ray Diffraction analysis performed to evaluate the hydration response of cement with LS and CKD showed greater conversion potentials of SiO2 to stable CSH.

Charge-induced low-temperature gelation of mixed proteins and the effect of pH on the gelation: A spectroscopic, rheological and coarse-grained molecular dynamics study.

We report the gelation of mixed proteins consisting of oppositely charged lysozyme and serum albumins at various pH. The results from rheological tests showed that at a pH of 7, the gelation temperature (Tgel) of the oppositely charged proteins was lower than the melting temperature (Tm) of the individual protein. To ascertain the conformational state of the proteins at the observed Tgel, the attenuated total-reflectance Fourier-transform infrared (ATR-FTIR) spectra of the proteins were acquired. The recorded spectra showed that the proteins were predominantly alpha helical, suggesting that the observed gelation was electrostatically triggered. However, as the solution pH was changed to acid or alkaline regime, all the proteins became similarly charged and showed Tgel <Tm which was attributed to pH-induced denaturation. Surprisingly, however, the serum albumins were remarkably stable at the alkaline pH of 9 and 10 but very labile at the acidic pH. In contrast, the LYZ was more stable at the acidic than alkaline pH. To understand the role of the opposite charges in the gelation, coarse-grained molecular dynamics (CGMD) simulations revealed an increase in the aggregation of the oppositely charged proteins compared with the pure or similarly charged protein mixture.

Influence of nano zirconia on the mechanical and durability properties of high-performance concrete containing nano-silica

High Performance Concrete (HPC) was prepared by reinforcing with hybrid nanoparticles such as nano-SiO2 and nano-ZrO2 and the flowability, strength and durability of the concrete was investigated. Slump study showed that the prepared HPC displayed a slump loss with the addition of hybrid nanoparticles due to the absorption of water by hybrid nanoparticles. Experimental results showed that the inclusion of 10% nano-SiO2 and 5% nano-ZrO2 hybrid nanoparticles (mix code M5) enhanced the compressive strength of concrete and exhibited a maximum of 50.12 MPa and 76.4 MPa at 7 days and 28 days of curing due to the reduction of pore volume. Split tensile strength followed the same trend of variation as compressive strength and the mix code M5 showed the maximum split tensile strength of 5.33 MPa and 7.08 MPa cured at 7 days and 28 days respectively. Flexural study resulted that the mix code M5 exhibited a maximum flexural strength of 5.73 MPa and 7.38 MPa cured at 7 days and 28 days respectively owing to the restriction of crack ignition by reinforced hybrid nanoparticles. Rheological study reported that all the prepared concretes lost the weight by less than 1% and the chloride attack displayed maximum weight loss of 4% whereas alkaline attack showed less weight of concrete.

Evaluation of Cassia fistula seed galactomannan as tablet-binder in formulation of diclofenac sodium-loaded monolithic matrix tablet

The present study aimed to evaluate Cassia fistula seed galactomannan (CFSG) as a tablet-binder in the formulation of a monolithic matrix tablet using diclofenac sodium as a model drug. Initially, CFSG was extracted and purified from the seeds of the Cassia fistula tree and then screened for phytochemicals. Native CFSG was characterized with polysaccharide content determination, monosaccharide composition analysis, elemental analysis, FTIR, solid-state 13C NMR, molecular weight, zeta potential, DSC, TGA-DTA, XRD, viscosity, pH and surface tension, rheology, SEM and acute oral toxicity study. Prior to formulation, the drug-CFSG compatibility was checked by FTIR, DSC, and XRD. Diclofenac sodium-loaded granules were prepared by the wet granulation method and evaluated for various granule properties. Finally, granules were compressed into tablets and evaluated for binding and other tablet properties. The granules showed to have optimum micromeritic properties. Tablet hardness and friability were found to be approximately 7 kg/m2 and 0.3 %, respectively, which substantiate the excellent binding capacity of CFSG. Other tablet properties were also found to be within the Pharmacopoeial compliance limit. The tablets with a minimum concentration of CFSG (2.5%w/w) as binder showed appreciable mechanical strength and faster drug release, which ratifies CFSG as an alternative tablet binder.

The synergistic effects of micro-and nano-fillers on the properties of polyamide 11/poly (lactic acid) blend

This study focused on investigating the effects of micro-scale carbon fibers (CF) and nano-scale graphene nanoplatelets (GNP) on the morphological, rheological, mechanical, thermo-mechanical and thermal properties of polyamide 11/poly (lactic acid) (PA11/PLA) blend. A twin-screw extruder and an injection molding machine were utilized to produce the samples. The amount of GNPs was varied up to 5 wt% for a fixed CF fraction of 20 wt%, and the composites were characterized. SEM micrographs of hybrid composites revealed stronger interfacial interactions between the matrix and CF and improved dispersion of GNPs. The pseudo solid-like behavior transition and high modulus detected in the rheological study with the addition of GNP confirmed the strong matrix-filler interactions in hybrid composites. The synergistic effects of multi-scale fillers have been observed in mechanical and thermo-mechanical properties. In comparison to 20CF, hybrid composites’ tensile strength and modulus increased by 8%–4.8% and 4.5%–17%, respectively, by adding 0.5–5 wt% GNP. Dynamic mechanical analysis revealed that the tan δ peak shifted to higher temperatures in low GNP containing hybrid composites, indicating an increase in Tg. Also, differential scanning calorimetry confirmed the Tg increment and synergistic effect of fillers on crystallization. The thermogravimetric analysis demonstrated that hybrid composites exhibited enhanced thermal stability. As a consequence, these hybrid composites offer an inventive viewpoint for environmentally friendly composites in the automobile industry thanks to their enhanced mechanical and thermal characteristics.

Designing functionalized polymers through post-polymerization modification of side chain leucine-based polymer

The opportunity to modify the chemical functionality of the incorporated amino acid moiety in side chain amino acid-based polymers provides access to tailor their optical, mechanical, and biological properties. Methacrylate monomers from C-terminus modified amino acids and their subsequent polymerization leads to the formation of polymethacrylate polymers with pendant amine (-NH2) groups. To this end, the post-polymerization reactions on the amine groups offer a facile route to prepare functionalized side chain amino acid-based polymeric materials. Herein, we synthesized side chain L-leucine pendant homopolymer using reversible addition-fragmentation chain transfer (RAFT) polymerization of Boc-L-leucine methacryloyloxyethyl ester (Boc-leu-HEMA) and subsequently the Boc group is deprotected to prepare P(H3N+-leu-HEMA). Post-polymerization modifications on the pendant amine groups were performed to incorporate fluorescent probe, propargyl group, methacrylic moiety, hydrophobic fatty acid, anionic pendant, and hydrophilic polyethylene glycol (PEG) units; which demonstrates an efficient platform to build a library of functionalized polymers from a single polymeric backbone. We have studied the solvatochromic behavior of fluorescence probe bearing polymers using fluorescence spectroscopy. The ability of the pendent methacrylic unit containing polymers to undergo crosslinking and the mechanical properties of the synthesized gel are investigated by the rheological study.

Influence of particle size on powder flow behaviour, textural and viscoelastic properties of milk-based whippable emulsions

This study focuses on the rheological, textural and powder flow characteristics of whippable oil-in-water emulsion with ingredients of different particle sizes (0.2, 0.5 and 1.0 μm) and compares them with the control sample. Rheological studies confirmed that all samples had shear thinning flow behaviour with higher determination coefficients (R2 >0.995). The smaller particle size further improved the dispersed phases, reducing the mean inter-particle distances. Therefore, the higher apparent viscosity resulted from particles being more difficult to move and inter-particle resistance rising. The adhesiveness tendency of the whippable emulsions decreased with increasing particle size. The highest cohesiveness value was determined in the control whippable emulsion and the lowest value was recorded at whippable emulsions containing 0.2 μm ingredients (0.2WC). This result suggests that whippable emulsion with a higher particle size was not easy to deform and was less crumbly.

Preparation, characterization and evaluation of hydrogels from different fractions of diverse medicinal plants for management of pain and inflammation

ABSTRACT Damage to body tissue either deeply or superficially causes pain sensation in response to which Inflammation occurs which is a normal protective natural response of the body to a variety of hostile agents. Different treatment options, including conventional and herbal therapies, are available for pain and inflammation. This study was designed to evaluate the polyherbal n-hexane and methanolic extracts and their hydrogel formulations prepared from commonly available medicinal plants for their analgesic and anti-inflammatory potential. Cinnamomum verum J. (bark), Moringa oleifera L. (leaves), Nigella sativa L. (seed), and Trigonella foenum graecum L. (seed) were collected and purchased from the vicinity and local market of Multan Punjab, Pakistan. After drying, extraction was carried out by maceration separately with two different solvents (methanol and n-hexane). An equal quantity of all methanolic and n-hexane extracts was used to formulate polyherbal methanolic and n-hexane extracts separately. Then 1%, 3%, and 5% pH-based hydrogel formulations of methanolic and n-hexane polyherbal extract were prepared. All prepared six formulations were evaluated for pH, rheological study, spreadability, extrudability, stability study, texture, color, and for toxicological study. Then analgesic and anti-inflammatory potential of methanol and n-Hexane polyherbal extracts at (200, 400 and 800.0 mg/kg) in comparison with diclofenac sodium (100 mg/kg) and prepared gel formulations (1%, 3%, and 5%) were also evaluated in comparison to diclofenac sodium 1% gel (standard drug). Both polyherbal extracts and their gel formulations have significant analgesic and anti-inflammatory potential but methanolic extract and its hydrogel have slightly more potential as compared to n-hexane extracts and its prepared hydrogel. Results also revealed that their gel formulations have more significant analgesic and anti-inflammatory potentials as compared to extracts. All pH-based gels have good texture, spreadability, extrudability, stability, and are safe to use. It is concluded that methanolic polyherbal extract and hydrogel prepared from methanolic extract have more analgesic and anti-inflammatory potential as compare to n-Hexane extract and hydrogel prepare from n-Hexane extract.

Product diversification to boost the sustainability of the shrimp processing industry: The case of shrimp-waste driven chitosan-based food Pickering emulsion stabilizers

Diversifying the product portfolio of the shrimp processing industry using its waste streams could contribute to its environmental sustainability and economic resilience. Considering that this study aimed to increase the commercial value of shrimp shell waste by using chitosan extracted from these wastes as a food emulsion stabilizer. More specifically, chitin was extracted from shrimp shell waste, and chitosan was then prepared from chitin by deacetylation. The findings showed that the extraction efficiency and degree of deacetylation of chitosan were 23% and 83%, respectively. After that, stearic acid was added to chitosan chains to improve its emulsifying properties. Then, the chitosan/stearic acid–stabilized flaxseed oil and olive oil emulsions were prepared in three oil ratios (20, 40 and 60%). The interfacial structure study showed that compared to flaxseed oil droplets, the olive oil droplets’ surface was better covered with the chitosan/stearic acid nanogels. Moreover, the rheological study indicated a stronger gel-like structure in olive oil emulsions than the flaxseed oil emulsions, particularly at 60% oil. The dried emulsions indicated that the olive oil was encapsulated better than flaxseed oil by the chitosan-based particles, and less oil leakage was observed for dried olive oil emulsions. Better encapsulation of olive oil with chitosan/stearic acid nanogels could be attributed to the higher polarity and viscosity of olive oil compared to flaxseed oil and the greater similarity of olive oil fatty acid profile with stearic acid attached to chitosan. In general, these findings showed that the stabilizer developed from shrimp shell waste is suitable for stabilizing emulsions containing more polar oils with less degree of unsaturation. The results obtained could contribute to enhancing the sustainability of the shrimp processing industry by diversifying its product portfolio.

Increasing Chemotherapeutic Efficacy Using pH-Modulating and Doxorubicin-Releasing Injectable Chitosan-Poly(ethylene glycol) Hydrogels.

Modulation of pH is crucial to maintaining the chemical homeostasis of biological environments. The irregular metabolic pathways exhibited by cancer cells result in the production of acidic byproducts that are excreted and accumulate in the extracellular tumor microenvironment, reducing the pH. As a consequence of the lower pH in tumors, cancer cells increase the expression of metastatic phenotypes and chemotherapeutic resistance. A significant limitation in current cancer therapies is the inability to locally deliver chemotherapeutics, leading to significant damage to healthy cells in systemic administration. To overcome these challenges, we present an injectable chitosan-poly(ethylene glycol) hydrogel that is dual-loaded with doxorubicin and sodium bicarbonate providing alkaline buffering of extracellular acidity and simultaneous chemotherapeutic delivery to increase chemotherapeutic efficacy. We conducted in vitro studies of weak base chemotherapeutic and alkaline buffer release from the hydrogel. The release of doxorubicin from hydrogels increased in a low-pH environment and was dependent on the encapsulated sodium bicarbonate concentration. We investigated the influence of pH on the doxorubicin efficacy and viability of MCF-7 and MDA-MB-231 breast cancer cell lines. The results show a 2- to 3-fold increase in IC50 values from neutral pH to low pH, showing decreased cancer cell viability at neutral pH as compared to acidic pH. The IC50 results were shown to correlate with a decrease in intracellular uptake of doxorubicin at low pH. The proposed hydrogels were confirmed to be nontoxic to healthy MCF-10A mammary epithelial cells. Rheological studies were performed to verify that the dual-loaded hydrogels were injectable. The mechanical and release properties of the hydrogels were maintained after extended storage. The chemotherapeutic activity of doxorubicin was evaluated in the presence of the proposed pH-regulating hydrogels. The findings suggest a promising nontoxic, biodegradable hydrogel buffer delivery system that can achieve two simultaneous important goals of local acidosis neutralization and chemotherapeutic release.

Emulsification of Indian heavy crude oil and analysis of flow characteristics using computational fluid dynamics (CFD) for pipeline transportation

The high viscosity of Indian heavy crude oils makes their pipeline transportation highly complicated and challenging. A huge pressure drop is observed while transporting heavy crude through pipelines. The present article addresses this complication by preparing a surfactant stabilized heavy crude oil-in-water (O/W) emulsion of a flowable viscosity to ease flow through pipelines. Different O/W emulsion samples were prepared with varying concentrations of a novel anionic surfactant, linear alkylbenzene sulfonic acid (LABSA), to achieve an optimized formulation based on rheological and stability studies. The article also discusses the effect of varying surfactant concentrations on interfacial tension, droplet size and distribution, and zeta potential of the developed emulsions. The optimized emulsion, having 60 vol% oil and 2 wt% surfactant, was further considered to simulate and analyze the flow characteristics (static pressure and velocity profiles) across the horizontal pipelines of three different inner diameters (0.1, 0.05, and 0.025 m) under three different inlet flow velocities (0.1, 0.05, and 0.001 m/s), using a computational fluid dynamics (CFD) approach. A remarkable decrease in the viscosity of heavy crude was noted after emulsification. Subsequently, the pressure drop across the pipeline was reduced significantly by order of three for the flow of O/W emulsion when compared to that of the heavy crude oil through a pipe diameter of 0.1 m at an inlet velocity of 0.1 m/s. The static pressure drop across the pipeline decreased with the increase in the pipe diameter; in contrast, it increased with the increase in the inlet velocity.

Rheological properties, printability and microstructure of buttermilk‐mashed potatoes incorporated with chlorpheniramine maleate as a material for 3D food printing

SummaryThree‐dimensional (3D) food printing is widely investigated in the food sectors, such as customised food designs, personalised nutrition and simplifying the supply chain. This study aimed to investigate the rheological properties and filament geometry of buttermilk‐mashed potatoes (BMP) to print 3D animal‐shaped foods through a syringe extrusion 3D printing technique using BMP as the printing material. The rheological studies showed that the BMP made with different weight ratios of mashed potato powder to milk‐water‐butter (BMP 1:4, 1:4.5, 1:5, 1:5.5 and 1:6) showed shear‐thinning properties that were suitable for 3D printing. The addition of liquid component is helpful in decreasing the viscosity of the BMP to flow through nozzles. Furthermore, water‐holding capacity decreased with an increased liquid ratio. The BMP 1:5 was optimal with high accuracy in all nozzles, and the optimal nozzle was 21G. It represented excellent shape fidelity and geometry. BMP1:5 with nozzle size 21G demonstrated 103.3% ± 1.3% active ingredient content, accurate ingredient content in various sizes of 3D‐printed objects and precision in weight. This study suggested that 3D printing based on BMP could produce complex‐shaped food patterns for further development and applications for active ingredient administration in children by a food base.

The Influence of Kaolinite and Quartz on Stability of Coal Froths - A Rheology and Structure Study.

Kaolinite and quartz are the common gangue minerals found in raw coal; however, their effects on stability of coal froths and subsequent settling of coal flotation products have not been investigated. In this study, in the coal froths batch settling tests, the amount of froth floating on top of water was 275, 325, 355, and 405 mL for coal concentrates generated with 0, 20, 40, and 60 wt % kaolin Q38, respectively, while that was almost the same (300-306 mL) for coal froth concentrates generated with 0, 20, 40, and 60 wt % quartz added in flotation, respectively, which turned out that the kaolinite could increase the stability of coal froth, while quartz could not. To investigate the mechanism, oscillatory rheology and scanning electron microscopy (SEM) were applied. The results of the oscillatory rheology suggested that the structural strength in coal froth was strengthened with the addition of kaolinite. In addition, images of Plateau borders by SEM illustrated that the addition of kaolinite in flotation increased the size of Plateau borders and generated network structures in the Plateau borders. However, as a comparison, the addition of quartz did not cause an obvious change for the oscillatory rheology and SEM results of coal froth. Based on the results, it can be concluded that network structures were generated in the Plateau border of coal froth with the addition of kaolinite, which increased its structural strength and retarded the drainage in froth. As a result, the stability of the coal froth increased.