Maximum Viscosity Research Articles

Heat Transfer Analysis and Friction Factor of Ternary Nanofluids with Twisted Tape Inserts

This study investigates the heat transfer efficiency and friction factor of ternary nanofluids (Al₂O₃-TiO₂-SiO₂) in a simple tube equipped with a twisted tape. Ternary nanofluids, prepared using a volume-based composition ratio of 20:16:64, were tested at various volume concentrations ranging from 0.5% to 3.0%. Forced convection heat transfer experiments were conducted under varying Reynolds numbers (2,300 to 12,000) and a bulk temperature of 70 °C. The results indicate that the maximum viscosity occurs at a volume concentration of 3.0%. The highest increase in heat transfer for ternary nanofluids in a simple tube with twisted tape (H/D = 2.0) was achieved at a volume concentration of 3.0%, reaching 225.35%. Compared to a plain tube, the average thermal performance factor (TPF) of the twisted tape was significantly improved, with a further increase observed when the volume concentration rose from 2.73% to 3.22%.

Variability of amylose content and its correlation with the paste properties of cassava starch.

The amylose content can significantly impact the diverse industrial applications of cassava starch. This study aimed to assess the variability of cassava germplasm concerning amylose content and other attributes pertinent to root quality, alongside its correlation with paste properties. Starch extracted from 281 genotypes, obtained in germplasm evaluation trials, was evaluated for amylose content, with additional analysis of parameters such as pasting temperature, time to peak viscosity (TPV), viscosity breakdown (BrD), retrogradation tendency, and maximum, minimum, and final viscosities. The genotypes exhibited considerable variation in dry matter content (ranging from 27.06% to 41.02%), starch content (from 14.61% to 25.67%), cyanogenic compounds (1.77 to 7.81), and amylose content (0.05% to 33.23%). High phenotypic variability in paste properties was observed, alongside a low residual effect for most traits, resulting in high broad-sense heritabilities (>0.95). Strong correlations of significant magnitude (>0.80) were found between parameters such as peak viscosity × viscosity breakdown, minimum viscosity × final viscosity, and final viscosity × retrogradation tendency. Moderate correlations were also identified, such as between dry matter content × starch content (0.56). While positive, correlations between amylose content and paste properties were of low magnitude (ranging from 0.13 to 0.35), except for TPV and BrD. Principal component discriminant analysis clustered the germplasm into six distinct groups based on root quality and paste properties, with most improved genotypes falling into two clusters characterized by high starch and dry matter contents. This study underscores the necessity of simultaneous evaluation of amylose content and paste properties in the breeding pipeline. Additionally, clustering cassava genotypes proves beneficial in identifying those that fulfill specific requirements in industrial and breeding applications.

Initially reactive and concentrated generalized fluid wavy flow with the applications of disorder theory and magnetic field: A computational study

The wavy flow of generalized fluid namely, Cross fluid is mathematically formulated on a gravitationally affected vertical wavy surface with significant physical effects which is the main theme of this work. This particular dynamics of chemically reactive materials is further explored with an irreversible process. A significant heat transfer is measured through thermal resistance during the consideration of entropy optimization. Since entropy generation is associated with the mechanical systemenergy loss is more helpful in monitoring the entropy production in different engineering and industrial processes. Specifically, such irreversibility process appearance causing a noticeable low efficiency in the relevant practical sectors. For better performance in the minimization of friction on the wavy surface, flow is dissipated in terms of heat. However, the measure of loss in terms of work is introduced in the form of thermal radiation, viscous dissipation, magnetic field, and first-order chemical reaction. Additionally, the expected pressure drooping on the wavy surface is another goal of the entire study. The non-linear mathematical equations are determined by following the maximum viscosity approach. Relevant and important results are portrayed to show the various features of the newly developed work. The significant findings are approximated via one of the collocation methods while using MATLAB software. The Richardson number and buoyancy parameter enhanced the flow speed of the materials. The heat transfer rate is decreased by both Eckert number and wavy amplitude and the chemical reaction factor enhanced the mass transfer rate. The heat energy of the materials is escalated with the help of electromagnetic wave radiation and temperature ratio factor. Strengthening the chemical reaction factor declined the mass flow during the typical motion of the liquid. In the last, a comparison is provided to show the accuracy of the numerical approach.

Harnessing nano-synergy: A comprehensive study of thermophysical characteristics of silver, beryllium oxide, and silicon carbide in hybrid nanofluid formulations

Nanofluids, promising to improve heat transfer efficiency, encounter stability and durability challenges, hindering their industrial applications. The emerging concept of hybrid nanofluids, alongside surfactant-driven stability research, presents a promising solution to tackle challenges in heat transfer, potentially revolutionizing thermal management systems and advancing nanomaterial science. This comprehensive study investigates the thermophysical properties of simple and hybrid nanofluid formulations composed of silver (Ag), beryllium oxide (BeO), and silicon carbide (SiC) nanoparticles dispersed in water. Hybrid nanofluids were prepared with varying volumetric ratios of 20:80, 40:60, 60:40, and 80:20 and examined across temperatures ranging from 15 to 45 °C. The influence of surfactants on stability was explored to augment thermal characteristics. Results revealed that the surfactants have a significant effect on stability and the specific mixing ratios can lead to more favourable thermal characteristics. Thermal conductivity enhancements, evaluated via the transient hot-wire method, demonstrated improvements of 7.43 %, 7.17 %, and 5.31 % for Ag/SiC (60:40), Ag/BeO (60:40), and SiC/BeO (80:20) hybrid nanofluids, respectively, compared to water. Viscosity measurements revealed Newtonian behaviour for the Ag, SiC, and BeO nanofluids, with a minimum viscosity enhancement of 3.01 % observed for the BeO nanofluid. Hybrid Ag/SiC nanofluid demonstrated a maximum viscosity enhancement of 4.90 % for 20:80 formulation. Density analysis showed maximum augmentation of 0.25 %, 0.097 %, and 0.0775 % for the Ag, SiC, and BeO nanofluids respectively at 0.025 vol% while hybrid Ag/SiC nanofluid exhibited a maximum of 0.23 % density increase for the 80:20 composition. The statistical models were also developed to predict properties against temperature. Furthermore, the cost analysis identified Ag nanofluid as the most expensive option, while the SiC/BeO hybrid was the most economical. However, the Ag-SiC (60:40) hybrid nanofluid offered a balanced trade-off between properties and cost.

Surrogate-assisted multi-objective Bayesian optimization for improved rheological design of bioinks

Extrusion bioprinting is a popular biofabrication technique for creating viable biological constructs with applications ranging from regenerative medicine and cancer research to therapeutics screening. A primary challenge within extrusion bioprinting lies in preserving cell viability and function amidst the shear forces generated during extrusion. Therefore, the formulation of shear-thinning bioinks with tailored flow properties is essential to minimize shear stress accumulation during printing. However, this task is complex, as the bioink’s flow properties are contingent upon numerous factors, including but not limited to the polymer concentration, spatial cell density in the bioink, molecular weight of the polymer, and the nozzle’s geometry. The current methods for adjusting flow properties are heuristic, posing challenges to the rapid development models and automation of the bioprinting workflow. In this study, we introduce a Gaussian Process-based multi-objective Bayesian optimization framework that rapidly identifies Pareto-optimal flow property values to minimize hydrodynamic shear stresses during extrusion. The optimization focuses on four flow parameters, minimum viscosity, maximum viscosity, consistency index, and flow behavior index from the power-law model of shear-thinning fluids alongside the nozzle outlet diameter. Following an initial set of 24 experimental runs, our sequential design approach required 21 iterations to achieve convergence on a set of flow parameters that meet the Pareto optimality criteria. The presented strategy, which integrates physics-based numerical models with data-driven optimization models, emerges as a tool for the rapid fine-tuning of bioink flow behaviors. The multi-objective framework also sets the stage for future exploration into cell viability and functional outcomes post-bioprinting.

Molecular interactions in ethyl caprate and 2-alcohol: Extended hard sphere framework

BackgroundThe study investigates the liquid densities and viscosities of Ethyl caprate (EC) combined with various 2-alkanols across a temperature spectrum of 293.15 to 323.15 K, aiming to understand the intermolecular interactions and deviations from ideal behavior. MethodsExperimental density and viscosity for the mixtures were measured with the SVM Stabinger viscometer. A modified rough hard-sphere theory was employed to model the viscosity of pure substances and binary liquids, incorporating temperature-dependent parameters. Significant Findings: All examined mixtures exhibited positive excess molar volumes. The modified rough hard-sphere model demonstrated a maximum viscosity error of 4.12 % for 2-hexanol in the temperature range of 293 to 323 K. For binary mixtures, the calculated values closely matched experimental data, with a maximum deviation of 3.51 % observed for the EC + 2-butanol mixture, highlighting the model's predictive accuracy.

Effect of particle size on SiO2 nanofluid viscosity determined by a two-step method

AbstractAccording to review of the literature, the influence of nanoparticle diameter with irregular shapes on viscosity requires further research since there is no relation between particle size and nanofluid stability. In this study, SiO2/EG–water-based nanofluid samples were prepared, and their viscosities were experimentally determined. SiO2 nanoparticles had sizes of 7, 15, and 40 nm, and the base fluid was a 50% ethylene glycol and 50% water mixture. Nanofluid samples were prepared using a two-step technique. Viscosity change was measured every 10 °C from 20 to 60 °C. The maximum viscosity values were observed for 7, 15, and 40 nm particles over an entire concentration range. Considering all measurements, the highest viscosity increase was 60.51% for 3% SiO2 (7 nm) at 60 °C, and the lowest viscosity change was 7.72% for 1% SiO2 (40 nm) at 40 °C. The most stable sample of the current study was 1% SiO2 (15 nm), and its Zeta potential was − 35.6 mV. Finally, a new empirical equation that included temperature, particle diameter, and concentration terms is suggested to predict dynamic viscosity, with R adj 2 = 0.98. It was also compared with previous correlations.

Low-energy micron dispersion of entangled polymers based on phase inversion composition of emulsion

This article aims to propose a low-energy method for micron dispersion of entangled polymers. We chose Ethylene-Propylene-Diene Monomer (EPDM) as the entangled polymer and acrylic esters as the dispersants to prepare the organic dispersion of the entangled polymer based on the theory that in-situ polymerization of acrylic esters had the higher solubility parameter than the original monomer. The dispersion process of entangled polymer was similar to the phase inversion of emulsion due to the maximum viscosity and minimum interfacial tension at the point of dispersion. Specifically, the average diameter of the dispersed entangled polymer was 5–6 μm. The system could still maintain excellent dispersion stability without additional dispersants. Rheology characterized that the introduction of aliphatic isocyanate derivatives reacting with hydroxyl groups in the polyacrylate to form the cross-linked skeleton could enhance the stability of the system. Excitingly, this organic dispersion allowed flexible printed circuit to fold at any angle and direction when used as the coating, and the coating still maintained excellent dispersibility, flexibility, insulation, and adhesion after aging tests. This low-energy method for micron dispersion of entangled polymers could expand their applications in coatings and other fields while maintaining their own characteristics.

The importance of acetate, pyruvate, and citrate feeding times in improving xanthan production by Xanthomonas citri.

Xanthan gum is a microbial polysaccharide produced by Xanthomonas and widely used in various industries. To produce xanthan gum, the native Xanthomonas citri-386 was used in a cheese-whey-based culture medium. The culture conditions were investigated in batch experiments based on the response surface methodology to increase xanthan production and viscosity. Three independent variables in this study included feeding times of acetate, pyruvate, and citrate. The maximum xanthan gum production and viscosity within 120 h by X. citri-386 using Box-Behnken design were 25.7g/l and 65 500 cP, respectively, with a 151% and 394% increase as compared to the control sample. Overall, the findings of this study recommend the use of X. citri-386 in the cheese-whey-based medium as an economical medium with optimal amounts of acetate, pyruvate, and citrate for commercial production of xanthan gum on an industrial scale. The adjustment of the pyruvate and acetate concentrations optimized xanthan gum production in the environment.

Value addition to dietetic frozen yoghurt through use of fruit peel solids

The study pertains to preparing value added frozen yoghurt through use of orange peel powder (OPP). The quality aspects of medium-fat (6.0% fat) frozen yoghurt prepared using OPP at three levels (1.5, 2.5, 3.5% as T1, T2 and T3 respectively) was studied. Frozen yoghurt was prepared by freezing blend of fermented yoghurt base with ice cream mix (25:75 w/w); other ingredients were sugar, stabilizer-emulsifier and orange crush. Inclusion of OPP in frozen yoghurt impacted the orange flavour favorably and enriched product with β-carotene and dietary fiber. The control product (TC) was prepared in similar manner, avoiding OPP. As the level of OPP was raised in formulation, there was a marked increase in the protein, carbohydrate, ash and total solids when compared with TC. Presence of OPP markedly affected the acidity, viscosity, overrun and melting resistance of the product; maximum overrun was associated with TC. Product T3 had the maximum acidity and viscosity; T2 had maximum total sensory score. It is recommended to prepare medium-fat frozen yoghurt utilizing 2.5% OPP along with orange crush as flavouring. Such inclusion of peel solids enriched the product with β-carotene and dietary fiber, contributed to stabilization of product and enhanced the products sensory acceptance.

Physicochemical properties of starch of four varieties of native potatoes

The limited industrial use of indigenous varieties of native potatoes has caused a decrease in its cultivation, restricting it to the self-consumption of the Andean population. The present study analyzed the physicochemical, thermal, and structural properties of the starches extracted from four of these varieties Aq'hu Pukucho, Yurakk Kkachun Wakkachi, Yurac Anca, and Huarmi Mallco, as a potential source of be used in industries such as food, pharmaceutical and, bioplastics. The percentage yield in wet extraction ranged between 14.53 and 20.26 %. The luminosity L* and whiteness index (WI) values were observed in ranges of 90.75–92.71 and 90.05–91.50, respectively. The Finding revealed various techno-functional properties, since the level of amylose varied between 36.29 and 43.97 %, an average zeta potential of −22 mV, and a maximum viscosity between 19,450–14,583 cP. The starches showed consistent thermal behavior since the TGA curves showed three stages with gelatinization temperatures that ranged between 54.9 and 59.75 °C, an enthalpy of 3.60–6.62 J/g, and various shapes of particles such as circular, elliptical, and oval. In conclusion, the relationships between variables such as water absorption index, swelling power, viscosity, crystallinity, enthalpy, and gelatinization temperature reveal different characteristics of each type of starch, which can influence its use.

Influence of parameters of the carbohydrate-amylase complex and protein content in grain on the baking quality of Winter Rye

The studies were carried out in 2018–2022. in the Samara region in order to identify the influence of the parameters of the carbohydrate-amylase complex and protein content in grain on baking properties in order to use the most informative indicators in the selection of winter rye for baking in the conditions of the Middle Volga region. The material was 4 varieties and 3 promising lines – Saratovskaya 7 (standard), Bezenchukskaya 87, Bezenchukskaya 110, Antares and lines GK-80, GKNP-3, GKNP-4. The soil is ordinary chernozem, medium deep, medium loamy, predecessor is pure fallow, repeated four times. The main parameters that determine the state of starch and influence the rheological properties of rye dough and baking evaluation reached: the «falling number» indicator – 188…255 s, the maximum viscosity on the amylograph – 424…570 u. a. The relationship between the height of the ammylogram and the «falling number» in 2019, 2020 and 2022. was strongly positive (r= 0.95; r= 0.89; r= 0.92). In 2020 and 2021 There was a positive correlation between the height of the amylogram and the volumetric yield of bread (r = 0.86; r = 0.82), the falling number also in these years was significantly positively correlated with the volumetric yield of bread (r = 0.65; r = 0.76). On average, over the years of research, the content of water-soluble pentosans, depending on the variety, varied from 2.46 to 3.00 %. In 2019, the highest values of this indicator were noted – 2.70…3.55 %, the volume of bread was also the highest – 520…655 cm3, and only this year a positive relationship was noted between the values of these indicators (r = 0.72). The relationship between pentosans and the «falling number», which is also responsible for the baking properties of winter rye, was significantly positive in 2019, 2020 and 2022. (r= 0.80; r= 0.78; r= 0.70). Protein content was positively correlated with bread volume yield (r=0.80; r=0.75) only in 2018 and 2019. A negative correlation was established between protein content and amylogram height in 2019, 2020, 2021, 2022. (r= –0.80; r= –0.80; r= –0.82; r= –0.78). There is also a negative relationship between protein content and the number of falls in 2019, 2020 and 2022 (r = –0.84; r = –0.80; r = –0.67). When selecting varieties of winter rye for baking, it is necessary to carry out conjugate selection based on the height of the amylogram and the «falling number» while stabilizing the protein at an acceptable level of 12.0…12.8 %.

Study on preparation and properties of antifreeze compound road dust suppressant

Open-pit mine pavement dust dries and breaks easily. As such, a composite pavement dust suppressant with good wettability, moisturizing, coagulation, and antifreezing properties in winter was investigated. Monomer screening and orthogonal experiments were conducted, using evaporation rate, permeability rate, viscosity, and freezing point as evaluation indexes. Consequently, a dust suppressant solution is a mixture of glycerol (GLY), sodium dodecylbenzene sulfonate (SDBS), polyacrylamide (PAM), compound propylene glycol (PG), and potassium acetate (PA). The characteristics of the dust suppressant and its interaction mechanism with road dust were measured and analyzed. The results showed that the optimal ratio of the antifreeze-type composite dust suppressant is 3%GLY, 0.30%SDBS, 0.07% PAM, and 50%PG + 10%PA; the contact angle is 27.62°, which can effectively wet coal dust. Moreover, it easily forms hydrogen bonds with water molecules to release free -OH, which increases the oxygen-containing functional groups in the dust. The maximum viscosity is 25.4 mPa·s, and the hydrophobic groups adsorbed on the surface of the dust can condense and agglomerate the dust to form large particles, and effectively inhibit the occurrence of dust. It freezes at − 34.2 ℃, resists a temperature of − 30 ℃ without freezing, and improves dust suppression efficiency and antifreezing effect in cold areas.

High-Speed Stress Field Measurement In A Soft Substrate During Droplet Impact

In this study, we utilized high-speed photoelastic tomography to quantify dynamic stress fields within a soft substrate during droplet impact. This manuscript details the measurement technique, which employs a high-speed polarization camera and the principles of photoelastic tomography. Our method successfully enabled the quantitative measurement of dynamic stress fields in a soft substrate during droplet impact. Additionally, we conducted an analysis of the impact force derived through the spatial integration of the measured stress field. The discussion explored the interplay between the maximum impact force, droplet viscosity, and substrate elasticity. Our findings indicate that the maximum impact force 𝐹max can be expressed as a function with a self-similar variable of 𝑅𝑒 / 𝐶𝑎^2 , where 𝑅𝑒 is Reynolds number representing the droplet inertial force and droplet viscous force and 𝐶𝑎 is Cauchy number representing the ratio of the droplet inertial force and substrate elastic force. This combination, 𝑅𝑒 / 𝐶𝑎^2 , represents the relationship between the relaxation time of droplet and substrate deformation ( 𝜂/ 𝐸), the contact time of the droplet (𝑅 / 𝑉), and the ratio of substrate elastic force to droplet inertial force. Consequently, the maximum impact force 𝑅𝑒 / 𝐶𝑎^2 is determined by the balance between the relaxation and contact times. We believe that our developed method will significantly enhance the understanding of droplet impact phenomena. Furthermore, it holds potential for broader applications in various engineering processes, such as analyzing stress distribution in materials caused by liquid jet impact and studying cavitation bubbles in viscoelastic materials. This method's ability to provide detailed quantitative measurements of dynamic stress fields offers a valuable tool for future research and technological advancements in related fields.

Nylon 12 composite optimization: Investigating influence of ceramic functional fillers on FFF 3D printing performance and rheological properties

AbstractFused Filament Fabrication (FFF) is a promising 3D printing technology for industrial and technological applications due to its cost‐effective ability to fabricate large, complex objects from thermoplastics. Nylon 12, a versatile thermoplastic, is widely used for functional prototyping and has significant potential for end‐user applications. Our research focuses on enhancing the mechanical and thermal properties of Nylon 12 by developing composites with ceramic fillers such as zinc oxide (ZnO) and alumina (Al2O3). This is achieved by melt mixing the fillers into the Nylon 12 polymer matrix and preparing filaments using a filament extruder. The optimal concentration of these fillers was determined by analyzing tensile strength of the polymer composites, while DSC was employed for thermal analysis. Additionally, rheological studies were conducted to assess the impact of the fillers on the viscoelastic properties and flow characteristics of Nylon 12. The Carreau‐Yasuda model was employed to study the complex viscosity of the materials. Our findings indicate that the addition of functional fillers enhances the shear thinning behavior of Nylon 12, improving material flow through the printer nozzle. This optimization leads to 3D printed structures with minimal dimensional inaccuracies, ensuring high‐quality prints suitable for commercial applications.Highlights Different functional fillers reinforced Nylon 12 composites‐based filaments for FDM 3D printing applications are manufactured. Different wt.% of functional fillers are added into Nylon 12 polymer matrix via melt mixing, and their filaments are prepared by filament extruder. Rheological studies of polymer composites were conducted to examine the influence of functional fillers in flow characteristics of polymer. The presence of functional fillers enhanced shear thinning behavior of polymer and develops maximum printable viscosity for extrusion‐based 3D printing.

PH-shift extraction followed by microwave and ultrasound modified functional properties of mustard meal protein

In this study, the pH shift method was used to extract the mustard meal protein, followed by microwave and ultrasound treatments to modify their functional properties. The yield of protein was influenced by pH, with the highest yield obtained (19.51%) at pH combination 12–4 and the lowest at 10–3 (3.08%). Both microwave and ultrasound treatments reduced the viscosities of the proteins from 1.97 cp (control) to 0.69 cp in ultrasound and 0.70 cp in microwave. The maximum viscosity was observed at pH combination 12–3 (1.29 cp) and the minimum at 9–3 (0.69 cp). Microwave treatment negatively affected the foaming capacity of the protein, while ultrasound treatment enhanced it, especially at pH combination 12–5. Oil holding capacity remained unchanged with microwave treatment, but ultrasound treatment increased it by exposing hydrophobic regions. Overall, this study highlights the potential of microwave and ultrasound treatments in modifying the functional properties of mustard meal protein.

Comparative Analysis of Maize Physico-Chemical Parameters and Mycotoxin Levels in Dual Environments.

Maize (Zea mays L.) stands as a vital staple food globally, holding significant nutritional and economic value. However, its susceptibility to mycotoxin contamination under stressful environmental conditions poses a considerable concern. This study aimed to assess the quality and pasting characteristics of maize varieties across two distinct regions and examine the occurrence of mycotoxins influenced by climatic factors. Five maize varieties were cultivated in triplicate in the Golegã and Coruche regions. The nutritional composition (protein, fat, fiber, ash, starch, and lutein), pasting properties, and mycotoxin levels were evaluated. A statistical analysis revealed notable differences in the nutritional profiles of the maize varieties between the two regions, particularly in the protein and lutein content. The peak viscosity ranged from 6430 to 8599 cP and from 4548 to 8178 cP in the maize varieties from the Coruche and Golegã regions, respectively. Additionally, a significant correlation was observed between the climatic conditions and the grain nutritional quality components (p < 0.05). The M variety showed the highest ash content, protein content, final viscosity, and setback viscosity and the lowest peak viscosity. The Y variety revealed the lowest fat, fiber, and lutein content and the maximum peak viscosity. The incidence of mycotoxins was notably higher in the varieties from Coruche, which was potentially attributable to higher temperatures and lower precipitation levels leading to more frequent drought conditions. Fumonisin B1 was detected in 58% of the varieties from Coruche and 33% of the samples from Golegã, while deoxynivalenol was found in 87% and 80% of the varieties from Coruche and Golegã, respectively. The H variety, which was harvested in Coruche, exhibited the highest number of fumonisins and higher amounts of protein, lutein, and fat, while fumonisins were not detected in the Golegã region, which was potentially influenced by the precipitation levels. The K variety revealed higher protein and lutein contents, a lower amount of fat, excellent pasting properties (a higher peak viscosity and holding strength and a lower peak time), and no fumonisins B1 or B2. This variety may be considered well adapted to higher temperatures and drier conditions, as verified in the Coruche region. In conclusion, our study underscored the profound impact of environmental factors on the quality and occurrence of mycotoxins in maize varieties.

Damping of density oscillations from bulk viscosity in quark matter

We study the damping of density oscillations in the quark matter phase that might occur in compact stars. To this end we compute the bulk viscosity and the associated damping time in three-flavor quark matter, considering both nonleptonic and semileptonic electroweak processes. We use two different equations of state of quark matter, more precisely, the MIT bag model and perturbative QCD, including the leading-order corrections in the strong coupling constant. We analyze the dependence of our results on the density, temperature and value of strange quark mass in each case. We then find that the maximum of the bulk viscosity is in the range of temperature from 0.01 to 0.1 MeV for frequencies around 1 kHz, while the associated minimal damping times of the density oscillations at those temperatures might be in the range of few to hundreds milliseconds. Our results suggest that bulk viscous damping might be relevant in the postmerger phase after the collision of two neutron stars if deconfined matter is achieved in the process. Published by the American Physical Society 2024

Physicochemical, Cooking Quality and Sensory Acceptability of Three Cowpea Varieties Grown in Botswana

Background: Information on the physicochemical, cooking and sensory qualities of cowpea seeds are required for nutrition information, to design processing and for consumer acceptance. In view of this, three cowpea varieties (Tswana, Blackeye and ER7) grown in Botswana were evaluated. Method: Proximate compositions, physical, gelatinization and sensory properties respectively were evaluated following AOAC, conventional, Amylograph and on 7-point hedonic sensory acceptability scale. Result: Significant variations (p less than 0.05) were observed in fat, fiber, ash and available carbohydrate (CHO) contents, length, thickness, hundred seeds weight (HSW), hydration capacity, hydration index, cooking time, flour starches maximum gelatinization temperature (Tm,°C) and viscosity at Tm. The percentage moisture, protein, fiber, fat, ash and available carbohydrate contents ranged 9.5-10.1, 21.7-22.8, 2.3-2.6, 1.1-2.0, 2.1-3.0 and 59.4-62.3, respectively. Initial gelatinization temperature (To,°C) and Tm (°C) were ranged 71.3(ER7)-73.7(Tswana) and 83.0(ER7)-84.7(Blackeye), respectively. Significant (p less than 0.05) variations in Tm and viscosity at Tm were observed because of differences in water uptake, swelling and thickening ability at high temperature. Longest cooking time was recorded for Tswana (43.57 min) while shortest was for Blackeye (36.10 min). Tswana recorded a longer cooking time probably because of low water hydration capacity, small seed size and low HSW. There was no significant difference in the sensory liking of the cooked cowpea seeds and were rated from slightly to moderately like. Cowpeas of high protein and fiber contents, short cooking time and high thickening ability on cooking are preferred for healthy diets. In terms of cooking time and thickening ability, Tswana variety appeared poor. Shorter cooking time, high protein content and high thickening ability of Blackeye cowpea is more acceptable. The ER7 is preferred for its large seed size.

Characteristics Of Partially Pregelatinized Sago Starch Extruded Under Various Conditions Using A Twin Screw Extruder Without A Die

Abstract This study aims to obtain the characteristics of PPSS as a binder extruded in a twin-screw extruder (TSE) without a die under 9 extrusion conditions selected from a systematic review. The Successive conditions: moisture content, last zone of barrel temperature, and screw speed for each condition were recorded. Respectively, the values were 32%, 60⁰C, 100 rpm for PPSS 1; 22%; 120⁰C; 250 rpm for PPSS 2; 22%, 100⁰C, 250 rpm for PPSS 3; 16%, 135⁰C, 150 rpm for PPSS 4; 10%, 160⁰C, 200 rpm for PPSS 5; 28.8%;, 100⁰C, 220 rpm for PPSS 6; 30%, 80⁰C, 200 rpm for PPSS 7; 25.2%, 97.5⁰C, 250 rpm for PPSS 8, and 30%; 135⁰C; 160 rpm for PPSS 9. The study informed that the degree of gelatinization (DG), water solubility index (WSI), water absorption index (WAI), and swelling power (SP) of PPSS 6 were the highest among the others but its bulk density (BD), degree of whiteness (DW), maximum viscosity (MV), and enthalpy were the lowest. Scanning electron microscopy showed that PPSS granules were irregular compared to their natural oval shape. Starch granule crystallinity indicated that some crystallines became amorphous and some increased (PPSS 3 and 4) while birefringence properties almost disappeared entirely.