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This paper aims to theoritically investigate the free convection flow and heat transfer of a non-Newtonian fluid with pseudoplastic behavior in a cylindrical vertical cavity partially filled with a layer of a porous medium.

The non-Newtonian behavior of the pseudoplastic liquid is described by using a power-law non-Newtonian model. There is a temperature difference between the internal and external cylinders. The porous layer is attached to the internal cylinder and has a thickness of D. Upper and lower walls of the cavity are well insulated. The governing equations are transformed into a non-dimensional form to generalize the solution. The finite element method is used to solve the governing equations numerically. The results are compared with the literature results in several cases and found in good agreement.

The influence of the thickness of the porous layer, Rayleigh number and non-Newtonian index on the heat transfer behavior of a non-Newtonian pseudoplastic fluid is addressed. The increase of pseudoplastic behavior and increase of the thickness of the porous layer enhances the heat transfer. By increase of the porous layer from 0.6 to 0.8, the average Nusselt number increased from 0.15 to 0.25. The increase of non-Newtonian effects (decrease of the non-Newtonian power-law index) enhances the heat transfer rate.

The free convection behavior of a pseudoplastic-non-Newtonian fluid in a cylindrical enclosure partially filled by a layer of a porous medium is addressed for the first time.

The purpose of this paper is to present a theoretical study of non-Newtonian effects in conical squeeze-film plates that is based on the Rabinowitsch fluid model.

A non-linear, modified Reynolds equation accounting for the non-Newtonian properties following the cubic stress law equation is derived. Through a small perturbation method, first-order closed-form solutions are obtained.

It is found that the non-Newtonian properties of dilatant fluids increase the load capacity and lengthen the response time as compared to the case using a Newtonian lubricant; however, the non-Newtonian behaviors of pseudoplastic lubricants result in reverse influences.

Numerical tables for squeeze-film loads of conical plates are also provided for engineering applications.

In the present paper, the authors aim to analyze the non‐Newtonian effects of Rabinowitsch fluids on the squeeze film performances between wide parallel rectangular plates.

Based on the cubic‐stress equation model, a nonlinear squeeze‐film Reynolds‐type equation has been derived. By using a small perturbation method, a closed‐form solution of the squeeze film characteristics is derived for the parallel plates considering the non‐Newtonian effects of cubic stresses.

Comparing with the Newtonian‐lubricant parallel plates, the effects of non‐Newtonian cubic‐stress flow rheology provide significant influences upon the squeeze film characteristics.

It is shown that the non‐Newtonian pseudoplastic behavior reduces the load capacity and the response time; however, the effects of non‐Newtonian dilatant lubricant provide an increase in the load‐carrying capacity and therefore lengthen the response time of parallel squeeze‐film plates.

Galactomannan gum isolated from the seeds of sesbania is subjected to chemical modification via phosphorylation. This is conducted via heating moistened blends of the gum with a mixture of orthophosphate salt. Three different phosphate ester derivatives are prepared by changing the reaction time. The %P increases from 0.07 to 0.12 to 0.61 by increasing the reaction time from 30 to 60 to 90 minutes.

Modification of sesbania gum via phosphorylation increases the stability of their pastes to storing. Investigation of the rhelogical properties of these pastes indicate that they are characterised by non-Newtonian pseudoplastic behaviour. As the extent of the reaction increases, i.e. %P, the apparent viscosity of the pastes at a constant rate of shear decreases, while storing does not change the rheological characteristics of the pastes.

Utilization of these derivatives as thickening agents in printing wool fabrics by using acid dyes indicate that phosphate derivatives of sesbania seeds could be used as a thickening agent in printing wool fabrics with acid dyes, where the K/S slightly decreases less than the commercial thickening agent named (Meypro gum) while the overall fastness properties are nearly identical.

The purpose of this paper is to prepare stabile emulsions with 0–15% of colloidal silica and high monomer/water ratio and to investigate the influence of silica addition and surface modification on the polyacrylate properties.

Improving the properties of the composite can be achieved by optimizing the compatibility between the phases of the composite system with improving the interactions at the matrix/filler interface. Therefore, the silica surface was modified with nonionic emulsifier octylphenol ethoxylate, cationic initiator 2,2'-azobis-(amidinopropane dihydrochloride) and 3-methacryloxypropyltrimethoxysilane and polyacrylate/silica nanocomposites were prepared via in situ emulsion polymerization. Particle size distribution, rheological properties of the emulsions and morphology, thermal properties and mechanical properties of the film prepared from the emulsions were investigated.

Polyacrylate/silica systems with unmodified silica, silica modified with nonionic emulsifier and cationic initiator have micrometer, while pure PA matrix and systems with silica modified with silane have nanometer particle sizes. Addition and surface modification of the filler increased emulsion viscosity. Agglomeration of silica particles in composites was reduced with silica surface modification. Silica filler improves thermal stability and tensile strength of polyacrylate.

This paper provides broad spectrum of information depending on filler surface modification and latex preparation via in situ emulsion polymerization and properties with high amount of filler and monomer/water ratio with the aim that prepared latex is suitable for film formation and final application.

In pursuit of affordable and nutrient-rich food alternatives, the symbiotic culture of bacteria and yeast (SCOBY) emerged as a selected food ink for 3D printing. The purpose of this paper is to harness SCOBY’s potential to create cost-effective and nourishing food options using the innovative technique of 3D printing.

This work presents a comparative analysis of the printability of SCOBY with blends of wheat flour, with a focus on the optimization of process variables such as printing composition, nozzle height, nozzle diameter, printing speed, extrusion motor speed and extrusion rate. Extensive research was carried out to explore the diverse physical, mechanical and rheological properties of food ink.

Among the ratios tested, SCOBY, with SCOBY:wheat flour ratio at 1:0.33 exhibited the highest precision and layer definition when 3D printed at 50 and 60 mm/s printing speeds, 180 rpm motor speed and 0.8 mm nozzle with a 0.005 cm³/s extrusion rate, with minimum alteration in colour.

Food layered manufacturing (FLM) is a novel concept that uses a specialized printer to fabricate edible objects by layering edible materials, such as chocolate, confectionaries and pureed fruits and vegetables. FLM is a disruptive technology that enables the creation of personalized and texture-tailored foods, incorporating desired nutritional values and food quality, using a variety of ingredients and additions. This research highlights the potential of SCOBY as a viable material for 3D food printing applications.

Chitosan is widely considered as a natural polymer and a diverse finish to impart antibacterial property and enhanced dye uptake of textiles. Herein, the authors have investigated the feasibility of using chitosan/starch blend as a thickener in screen printing of cellulosic fabrics with some natural dyes.

The polymeric blend of chitosan/starch was prepared and used as a thickener for screen printing with three natural dye extracts, namely, Curcuma tinctoria (turmeric), Beta vulgaris (beet) roots and Lawsonia alba (henna) leaves on cellulosic fabrics like cotton and viscose. The viscosity and rheological properties of print paste as a fresh and after overnight shelving were examined. The influence of polymeric blends on cellulosic fabrics' print properties was inspected by determining their colorfastness, rubbing fastness, tensile strength and antibacterial activity.

The results depicted that chitosan/starch blend as printing thickener increased the shade depth with good wet and dry rubbing fastness for all the test natural dyes. The antibacterial activity of resultant printed cellulosic fabrics was found to be satisfactory against broad-spectrum bacterial strains.

This study's outcome is the development of chitosan blend thickeners to print the cellulosic fabrics with indigenous natural dyes.

The authors found no previous report on the synthesis of chitosan-based antibacterial blend thickeners with three distinct natural dyes and their application in screen printing of native and regenerated cellulosic fabrics of cotton and viscose, respectively.

The purpose of this paper is to prepare ultra-violet (UV)-curable inkjet inks for textile printing application. The influence of both type and component ratio of monomer/oligomer on the quality of the desired viscosity range is studied. Moreover, the effect of pigment/resin ratio on the rheological behaviour of the ink has been studied.

Aqueous dispersions of nanoscale organic pigments were prepared through ball milling and ultrasonication. The dispersed pigments were encapsulated into UV-curable resin via miniemulsion technique, using different types and component ratios of monomers and oligomers.

It was found that the monomer/oligomer ratio of 2:3 and the pigment/resin ratio of 2:1 gave the most stable miniemulsion dispersions and provided the most suitable rheological range for inkjet printing inks.

As the rheology of the ink is optimised, most of the problems associated with the jetting process could be avoided.

This method of using UV-curable encapsulated inks eliminates the usage of binders, which are the principal factor for nozzle clogging of the print head. In addition, binders are responsible for the coarse handle of the printed textiles.

The UV-curable inks were viewed as a green technology by the US Environmental Protection Agency.

This method is simple and fast and requires low cost. In addition, it could find numerous applications in surface coating.

The flow development and heat transfer in a differentially heated cavity containing a non‐Newtonian fluid is studied using CFD techniques. Investigations are made for a fluid obeying a power‐law type behaviour, for a nominal Rayleigh number of 10⁵. Both dilatant and pseudoplastic regimes are considered and the Nusselt number is obtained for a range of power‐law index values. The results, given in a graphical and tabular form, suggest that deviations from Newtonian stress‐strain behaviour can lead to large changes in overall heat transfer. These changes are due to the behaviour of the wall boundary layers. In the dilatant, or shear‐thickening regime, the isothermal wall layers are thick and slow‐moving; as a consequence, buoyancy induced flow affects the whole of the cavity volume. In contrast, the pseudoplastic (or shear‐thinning) regime leads to thin, fast‐moving wall layers whose effect does not propagate to the core of the cavity which remains stagnant. This behaviour, which is directly attributable to the local value of the fluid viscosity, causes the average Nusselt number to decrease with the power‐law index, n. Pseudoplastic fluids are therefore better at conducting heat than Newtonian fluids, and conversely dilatant fluids are worse. The information contained in this paper is of general interest to workers in heat transfer, but is more specifically relevant to researchers in non‐Newtonian fluids. Example applications include biotechnology, where close temperature control of bio‐cultures in enclosed vessels is required, the food processing industry, the metals casting industry and areas where heat transfer in fine suspensions is required.

The purpose of this study is to successfully apply ultrasonic waves for the quick extraction of flax seed gum from flaxseed hull or whole seed and compare it to the standard technique of extraction.

The effect of the heating source, extracted time, temperature and pH of extracted solution on the extraction was studied. The obtained gum is subsequently used for silk screen printing on cotton, linen and viscous fabrics. Rheological properties and viscosity of the printing paste were scrutinized in the current study to get a better insight into this important polysaccharide. The output of this effort aimed to specify the parameters of the processes for printing textiles to serve in women’s fashion clothes by applying innovated handmade combinations of Islamic art motives using a quick and affordable method. Seven designs are executed, and inspiring from them, seven fashion designs of ladies’ clothes were designed virtually by Clo 3D software.

The result recorded that the new gum has excellent printing properties. In addition, they have better rheological properties, viscosity, chromatic strength and fastness qualities, all of which could help them in commercial production.

Flaxseed and three different fabric types (Cotton, Linen and Viscous) were used.

Synthesis of a new biodegradable thickener from a natural resource, namely, flaxseed, by applying new technology to save time, water and energy.

Synthesis of eco-friendly biodegradable thickener and used in textile printing alternative to the synthetic thickener.