Viscosity Temperature Research Articles

The impact of different soluble endogenous proteins and their combinations with β-glucan on the in vitro digestibility, microstructure, and physicochemical properties of highland barley starch

The impacts of protein types and its interaction with β-glucan on the in vitro digestibility of highland barley starch were investigated through analyzing physicochemical and microstructural properties of highland barley flour (HBF) after sequentially removing water- (WP), salt- (SP), alcohol- (AP) and alkali-soluble (AlkP) proteins. Resistant starch (RS) increased significantly in HBF after removing WP and SP, and RS of HBF was lower than that of without β-glucan. After removing WP, SP and AP, swelling powers of HBF without β-glucan (9.33–9.77) were higher than those of HBF (12.09–15.95). Trends of peak viscosity and peak temperature (thermal degradation temperature) were similar as swelling power, and HBF without AP showed the highest peak temperature (310.33 °C). Removals of different proteins improved the crystalline structure and short-range order of starch. There was a blue shift in T2 values and an opposite change in free water proportion. The matrix on starch surface was mainly formed by AP and AlkP, which could be aggregated by β-glucan. But, the inhibitory effect of AP or AlkP was stronger than that of proteins combined with β-glucan. These results help in the development of starch-based foods with different digestive properties by combining different protein types with β-glucan.

How do stretch rate, temperature, and solvent exchange affect elastic network rupture?

In this study, we investigate three different polymeric networks in terms of their tensile strength as a function of stretching rate, or temperature, or medium viscosity. Both an acrylate-based elastomer and a crosslinked poly(methyl acrylate) are stronger, more stretchable, and tougher at high rates. They are also much stronger at lower temperatures. Such phenomena systematically suggest that the kinetics of bond dissociation in backbones of those load-bearing strands dictate the rate and temperature dependencies. We apply Eyring's activation idea for chain scission to rationalize the influence of rate and temperature on rupture for both elastomers and hydrogels where hydrogels become much more stretchable and stronger when water is replaced by glycerol.

Otimização das propriedades reológicas das massas de pães com substituição de farinha de trigo por farinhas de grão inteiro de pseudocereais Andinos germinados

ABSTRACT: This study optimized the rheological parameters of doughs with partial substitution of wheat flour for blends of whole grain flours from germinated Andean pseudocereals such as quinoa (GQF), kiwicha (GKF), and cañihua (GCF) for bread production. The optimization was conducted through a Simplex-Centroid Mixture Design (SCMD) and Desirability Function (DF). Experiments were formulated using 80 to 90% wheat flour and 5 to 15% germinated pseudocereal blends. The rheological evaluation included farinograph, extensograph, and amylography analyses. Results showed that whole flour from germinated pseudocereals increases the water absorption, consistency, and extensibility of the doughs; and decreases its development time, stability, resistance to extensibility, temperature, and peak viscosity. The GQF-GKF blend developed more extensible and stable doughs, while GCF increased its consistency and was recommended for bread production. The data allowed us to obtain response surface models and the optimal substitution percentages to produce bread using GQF-GKF, GQF-GCF, and GKF-GCF blends.

Impact of cure Temperature and suspension viscosity on the Mechanical Properties of Carbon Nanofiber-Reinforced Epoxy Resin Nanocomposites

The application of nanocomposites in several industrial applications has been increasing due to their good specific strength and stiffness. In this context, carbon nanofibers (CNFs) are the most promising carbon-based nanoparticles due to their good mechanical, electrical, and thermal properties. Therefore, because they are widely used with epoxy resins for application in various industrial sectors (railway, automotive, aeronautics, and process industries), it is necessary to understand their interaction during the manufacturing process. Consequently, the main goal of this study is to analyze the effect of suspension viscosity on mechanical properties. For this purpose, different tests were carried out, such as resin viscosity tests, measurement of the contact angle between CNFs and resin, as well as shrinkage tests. The effect of cure temperature, between 5°C and 40°C, on the mechanical performance of nanocomposites was also evaluated. It was possible to conclude that CNFs increase the viscosity between 27.3% and 74.7% depending on the resin, and the shrinkage effect decreases from 3.2% to 0.5%. For all the materials studied, an increase in cure temperature decreases the flexural strength. Considering a cure temperature of 40°C, neat Sicomin resin has a flexural strength of 91.4 MPa, but when it decreases to 5°C there is an increase of 38.4%. The same comparison for neat Ebalta resin leads to values of 92.3 MPa and 27.8%, respectively.

Research on the variation of dielectric properties of oil‐paper insulation for power equipment over a wide temperature range

AbstractThe main part of oil‐immersed power equipment is oil‐paper insulation. At lower ambient temperatures, transformer oil will become viscous. As a result, compared to those at room temperature or operating temperature, the frequency domain dielectric properties of oil‐paper insulation at low temperatures are drastically different. For evaluating the insulation condition of electrical equipment, it is essential to accurately determine their dielectric properties. This paper described the FDS test, the DC conductivity test, and the transformer oil viscosity test, which was carried out in a laboratory environment for different ageing of oil‐immersed pressboard and transformer oil at 233–373 K. The effects of temperature on the dielectric properties at the competing mechanisms of polarisation and conductivity loss were clarified based on variations of the FDS curves. Considering the viscosity change of ageing transformer oil at low temperatures, the Arrhenius and VFT viscosity equations were used to achieve a fitting calculation in the different temperature zones. Based on the molecular/ion transition model in the force field and electric field, the characterisation relationships between the dynamic viscosity, DC conductivity, and test temperature of transformer oil were established. The limitations of conventional transformer oil equivalent dielectric relaxation models over a wide temperature range were finally clarified by combining the test findings of the DC conductivity over a wide temperature range with observed and simulated calculations. This paper provides an essential theoretical reference when using the FDS test to diagnose the insulation performance of oil‐immersed power equipment in extremely cold regions.

Simulation by coupling of the level set and thermal methods to extruded material flow in 3D printed polymers

Fused deposition modelling (FDM) in polymers provides new opportunities for the manufacturing of components with customizable geometries and mechanical properties, with high speed and low cost. To this end, we propose a computational framework for the simulation of the printing process of the flow during low density polyethylene (LDPE) material extrusion, coupled to thermal, level set method and CFD phenomena. This work presents an FEM (finite element method) mathematical model that describes as result of the melt parameters of the polymer flow, such as, the volume fraction, temperature field, the pressure distribution of the mixed phase, velocity distribution, temperature gradient field and viscosity dynamic in different times, in different parts of the extruder geometry of a 3D printer, based on FDM technique. The result of the melt parameters in the process are not uniform; they vary across in the cross-section area of the nozzle and in the form area for depositing the material. The result was coherent with the literature.

Физико-химические свойства растворов перхлората и тетрафторбората лития в смеси сульфолана и сернистого ангидрида

The temperature dependencies of physical and chemical properties (viscosity, density, electrical conductivity) and the melting temperature of 1M solutions of lithium salts (LiClO4 and LiBF4) in the mixture of sulfolane and sulfurous anhydride (∼1M) were studied. It was shown that the introduction of 1M (5% wt.) of sulfurous anhydride into 1M solutions of LiClO4 and LiBF4 in sulfolane increased the specific and corrected electrical conductivity, densities, activation energy of electrical conductivity and viscous flow of electrolyte solutions; and reduced viscosity and melting temperatures.

MODELS FOR THE FORMATION OF POLYPHASE GABBRO-MONZODIORITE MASSIFS OF THE WESTERN SANGILEN IN THE COLLISIONAL AND TRANSTENSIONAL-SHEAR SETTINGS

A model for the formation of intrusions of the collision stage of 525–490 Ma and a model of magmatism of the transtensional shear stage of 465–440 Ma within the Mugur-Chinchilig and Erzin-Naryn blocks of Western Sangilen (Tuva) have been developed to describe the process of crust-mantle interaction. Model experiments confirm petrological data on the presence of multi-level chambers during the formation of the Pravotarlashkinsky and Bashkymugur massifs. The proposed model describes the migration of mantle magmas above the head of the mantle plume at the collision stage and assumes the rise of magmas along a permeable tectonic zone in the mantle lithosphere and crust at the transtensional-shear stage. The modeling results allow us to establish that material from the magma chamber can reach depths of the upper crust in the volume ratio of gabbroids to diorites from 1 : 2 to 3 : 4 and additionally introduce about 5 % of the volume fraction of lower crustal material.The physical parameters of the primary magmas (viscosity, solidus and liquidus temperatures, degree of melting depending on temperature and composition, change in density) were calculated taking into account the real geochemical characteristics of igneous rocks from the polyphase massifs of Western Sangilen.

Mathematical modelling of drilling mud plastic viscosity at downhole conditions using multivariate adaptive regression splines

Viscosity is an essential mud property which enables it to transport cuttings out of a well. Determining the real time value of mud viscosity at downhole conditions is complex and till date lacks a precise model. Literature is filled with models that are only applicable at surface conditions with most of the models being artificial neural network (ANN) based. Neural networks have been criticized for their long training time because they rely on a trial-and-error approach to determine their optimal architecture. The few models related to mud viscosity at downhole conditions are based on non-linear regression which are not flexible in nature. However, Multivariate Adaptive Regression Splines (MARS) has at no time been used notwithstanding some of its known benefits over ANN and other regression methods. The focus of this study is to model mud plastic viscosity at downhole conditions with the MARS method using parameters such as temperature, pressure and initial mud viscosity. MARS is a flexible non-parametric splines-based technique that extends linear regression models by including nonlinearities and interactions between predictors. An experimental database comprising 88 and 149 data points culled from literature for oil-based mud (OBM) and water-based mud (WBM) respectively were utilized for developing the models. For each mud type, the most suitable model was determined by choosing the model with the maximum coefficient of determination (R2) value and the least values of mean square error (MSE), root mean square error (RMSE), and generalized cross-validation criterion (GCV). Using these criteria, the R2, MSE and RMSE of the MARS models according to the mud type were found to be 0.64, 104.35, 10.21 and 0.71, 12.8, 3.57 for OBM and WBM respectively while the GCV values were 129.3 and 14.38 for OBM and WBM respectively. Due to lack of mud rheology data at downhole conditions, it was difficult to compare the performance of the developed models with existing models. Parametric importance analysis indicate that temperature has the highest effect on mud viscosity estimation at downhole conditions. The developed models are valid for 20 °C ≤ Temperature ≤315 °C and 0 psi ≤ Pressure ≤40,000 psi. This pioneer work on using MARS in drilling fluid property prediction points out the implementation protocol, the dataset utilized, the relative importance of input variables and the explicit model for estimating mud viscosity at downhole conditions.

Hydroxypropylation for functional enhancement of sago starch: The effects of low propylene oxide concentration using response surface methodology

Native sago starch is currently limited to food and adhesives due to its functional constraints, requiring improvement for broader industrial use. Hydroxypropylation is a modification technique used to enhance the functional properties of starches. However, propylene oxide usage is restricted owing to safety and environmental concerns during the modification process. Therefore, hydroxypropylation with a low dose of propylene oxide was selected to improve the functional characteristics of the sago starch with the desired molar substitution. The Response Surface Methodology (RSM) was chosen to optimize hydroxypropylation with the following factorial process variables: volume of 7 % w/w propylene oxide (6–18 ml), reaction pH (9−12), reaction time (3–8 h), and the desired molar substitution (MS) as a response variable was 0.100. The optimization was achieved at 17.03 ml of 7 % wt. of propylene oxide, reaction pH 11.92, and reaction time of 3 h. Hydroxypropylation has effectively increased the functional properties of sago starch including swelling power, water-holding capacity, oil-holding capacity, and solubility of sago starch as well as paste and setback viscosity. However, hydroxypropylation reduced the amylose content, gelatinization temperature, and breakdown viscosity. The RSM with a low propylene oxide concentration successfully optimized sago starch hydroxypropylation and enhanced its functional properties. Hydroxypropylated sago starch using low propylene oxide could be further studied as a potential thickener in the food industry.

Rheological Characterization and Tribological Evaluation of Water-Based Lubricants in AISI 52100 Bearing Steel

This study explores the rheological and tribological behavior of water-based lubricants (WBLs) as potential alternatives for electric vehicle (EV) applications. As the transportation sector increasingly shifts towards EVs to reduce carbon emissions, the demand for efficient lubricants becomes critical. WBLs here are defined as fluids containing a minimum of 50 wt% water mixed with glycerol, ethylene glycol (MEG), polyethylene glycol (PEG), or one of two polyalkylene glycols (PAGs). Rheological properties were investigated and compared with traditional lubricating oils. Results demonstrate distinctive rheological characteristics in WBLs, with viscosity–temperature responses resembling traditional oils with lowered pressure–viscosity coefficients. Nevertheless, WBLs exhibit promising film-forming capabilities in highly loaded contacts. Additionally, in sliding contacts, WBLs generally display lower friction coefficients compared to traditional oils, with PEG exhibiting the lowest value near 0.1. These findings suggest that WBLs may offer advantages in reducing friction and energy loss in EV applications. Furthermore, sliding wear tests indicate low wear rates in WBLs such as PEG, PAG, and glycerol, supporting their potential as viable lubrication options. The study highlights the importance of high-pressure rheology and tribochemistry in wear mechanisms among the different lubricants.

Energetic binder - P(AMMO-ab-EG) alternate block copolyethers with strict controlled segment length

The flexibility of high energy polymers is hindered by bulky and polar high energy groups, resulting in reduced mechanical properties. In this paper, poly(3-azidomethyl-3-methyloxetane-glycol) (P(AMMO-ab-EG)) with an alternating block structure was synthesized and characterized. Diethylene glycol and triethylene glycol are used to improve flexibility, which length in this polymer structure is tightly controlled. (P(AMMO-ab-EG)) exhibits good flexibility, suitable viscosity and good thermal stability. It was found that P(AMMO-ab-DEG) exhibited a lower glass transition temperature but higher viscosity and better temperature viscosity sensitivity than P(AMMO-ab-TEG). These results demonstrate that fine tuning of the block length has a greater effect on Tg than on viscosity. This finding is of great significance to prepare energetic polymers with good processing properties and lower Tg value. Al, the prepared (P(AMMO-ab-EG) has excellent compatibility with NG (nitroglycerine) and NP (bis(2,2-dinitropropyl)acetal and bis(2,2- dinitropropyl)formal).

Physicochemical indicators coupled with statistical tools for comprehensive evaluation of the novel infrared peeling on tomatoes

The peelability of fruit is influenced by numerous factors; thus, it is critical to identify key factors to anticipate peelability. This study aimed to examine variations in peelability and key indices of tomatoes at various infrared (IR) parameters, and their quantitative relationships, using Pearson's correlation and multiple linear regression (MLR) statistical tools. Results showed that the peelability during IR treatment could be quantitatively reflected by content, esterification degree (DE), intrinsic viscosity of pectin, surface temperature, intracellular and extracellular resistance, and relative electrolyte leakage (REL). Among them, contributions of REL, pectin content, DE of pectin, and surface temperature to peelability were more significant. This is because as IR's time and temperature increased, tomatoes' surface temperature increased, leading to the degradation of pectin, and changes in DE of pectin and REL. This contributed to thermal softening of peel and decreased adhesions of cells, leading to skin loosening. Skin loosening along with accumulated pressure improved skin rupture, improving peelability. This peeling model was statistically significant (Adjust R2 = 0.971, Sig. of F-test <0.01), with no outliers, and residuals were independent and normally distributed. Overall, this model can simplify data collection, assist in determining more suitable infrared peeling parameters, and improve the peelability of tomatoes.

Fabrication of functionalised graphene-PAEK nanocomposites for different manufacturing processes

ABSTRACTAchieving good dispersion of graphene (GNP), in polyetheretherketone (PEEK), is challenging due to the high melt viscosity, solvent resistance and processing temperature of PEEK. In addition, certain manufacturing processes tend to enhance the anisotropy due to GNP orientation within the structure. This study investigated the fabrication of nanocomposite parts through hot compression moulding (C-MOULD) and powder bed fusion (PBF) processes, using powder with GNPs fused to the surface of polymeric particles, through a process called mechanofusion. The method applies mechanical forces of compression, shear and impact to generate a mechanical bond between materials, in this case, O2 functionalised GNP and a developmental polyaryletherketones (PAEK) grade powder. The novelty of this work is in the combination of processes used for manufacturing (material preparation and actual manufacturing processes), which are scalable and efficient in comparison with existing methods (such as solvent mixing or melt-compounding). The mechanofusion GNP-PAEK composite powders were successfully printed for the first time using the EOS P800 system with notable improvements in electrical and mechanical properties. This study highlights that the mechanofusion process could be used as an efficient process for making multifunctional nanocomposite materials and this can be combined with additive manufacturing (AM) processes to produce complex components.

Parameterizing smooth viscous fluid dynamics with a viscous blast wave

Blast wave fits are widely used in high energy nuclear collisions to capture essential features of global properties of systems near kinetic equilibrium. They usually provide temperature fields and collective velocity fields on a given hypersurface. We systematically compare blast wave fits of fluid dynamic simulations for Au+Au collisions at and Pb+Pb collisions at TeV with the original simulations. In particular, we investigate how faithful the viscous blast wave introduced in Yang and Fries (2022 Phys. Rev. C 105 014910) can reproduce the given temperature and specific shear viscosity fixed at freeze-out of a viscous fluid dynamic calculation, if the final spectrum and elliptic flow of several particle species are fitted. We find that viscous blast wave fits describe fluid dynamic pseudodata rather well and reproduce the specific shear viscosities to good accuracy. However, extracted temperatures tend to be underpredicted, especially for peripheral collisions. We investigate possible reasons for these deviations. We establish maps from true to fitted values. These maps can be used to improve raw fit results from viscous blast wave fits. Although our work is limited to two specific, albeit important, parameters and two collision systems, the same procedure can be easily generalized to other parameters and collision systems.

Thermohydrodynamic Lubrication Characteristics of Piston Rings in Diesel Engine Considering Transient Heat Transfer under the Parameterized Surface Texture of Cylinder Liners

The cylinder liner and piston ring form the most crucial friction pair in the diesel engine, contributing 35–40% of its overall friction losses. Recent research indicates that transient heat transfer significantly affects piston ring lubrication. However, the impact of such a transfer on varying surface textures and lubrication traits remains unclear. This paper takes the piston ring–cylinder liner of a certain diesel engine as the research object, which is based on a two-dimensional averaged Reynolds function and Greenwood–Tripp micro convex body contact model; establishes a numerical calculation model of the transient heat fluid lubrication characteristics of a vertical piston ring–cylinder liner assembly by combining the oil film thickness equation, energy equation, lubricating oil viscosity–temperature, and viscosity pressure characteristics; avoids large errors associated with assuming different temperature values for lubricants; and also uses the cylinder liner surface texturing technique to examine the effects of surface texturing on lubrication properties in the presence of transient thermal fluids. The findings indicate that employing transient thermal fluid for determining the mean value of the oil film temperature in isothermal lubrication calculations yields comparable values for minimum oil film thickness and frictional power consumption, while the friction power consumption calculated by the transient thermal fluid is slightly lower. The depth of the recesses on the surface of the cylinder liner should be minimized, while the radius of the texture should be maximized, taking into consideration the current circumstances. Compared with a cylindrical texture, a spherical texture achieves lower friction with good lubrication indexes.

Wellbore-heat-transfer-model-based optimization and control for cooling downhole drilling fluid

To address the two critical issues of evaluating the necessity of implementing cooling techniques and achieving real-time temperature control of drilling fluids underground in the current drilling fluid cooling technology, we first established a temperature and pressure coupled downhole heat transfer model, which can be used in both water-based and oil-based drilling fluid. Then, fourteen factors, which could affect wellbore temperature, were analyzed. Based on the standard deviation of the downhole temperature corresponding to each influencing factor, the influence of each factor was quantified. The influencing factors that can be used to guide the drilling fluid's cooling technology were drilling fluid thermal conductivity, drilling fluid heat capacity, drilling fluid density, drill strings rotation speed, pump rate, viscosity, ROP, and injection temperature. The nondominated sorting genetic algorithm was used to optimize these six parameters, but the optimization process took 182 min. Combining these eight parameters' influence rules with the nondominated sorting genetic algorithm can reduce the optimization time to 108 s. Theoretically, the downhole temperature has been demonstrated to increase with the inlet temperature increasing linearly under quasi-steady states. Combining this law and PID, the downhole temperature can be controlled, which can reduce the energy for cooling the surface drilling fluid and can ensure the downhole temperature reaches the set value as soon as possible.

Investigation of the effect of BaO-Al2O3 variations for BAS glass-ceramic glaze: Insights into thermal, phase, microstructural and surface features

This study aims to investigate the phase transformation, thermal behavior, microstructure evaluation and surface feature of the barium aluminosilicate (BAS) glass-ceramic glaze by changing barium oxide (BaO) and aluminium oxide (Al2O3) amounts. Differential thermal analysis (DTA) analysis showed that the first crystallization occurred at 800 °C and referred to the celsian formation, and crystallization temperature increased as Al2O3 content increased. Characteristic temperature and high thermal viscosity behavior was examined by hot-stage microscope analysis and the Vogel–Fulcher–Tammann (VFT) equation. X-ray diffraction (XRD) analysis showed that replacing Al2O3 with BaO resulted in an enhanced celsian (Ba0.8Al1.6Si2.4O8) phase. On the other hand, increasing Al2O3 content promoted the corundum (α-Al2O3) phase. The glassy and crystalline phase amount was determined by using Rietveld method. Field Emission Scanning Electron Microscope (FESEM) observations showed rectangular, strip-like celsian crystals, unshaped corundum crystals and porous microstructure. Surface roughness and the height distribution of surfaces were supported by 3D topographic mapping and determined according to ISO 4287. The highest BaO-contained R1 exhibits lower peaks with 190 µm and valleys with 80 µm, on the contrary, the highest Al2O3-contained R5 has high peaks with 252.7 µm, and deep valleys with 150 µm. Finer celsian crystals and lowest surface roughness ensured the cleanability of the surface and resulted in Class 5 according to ISO 10545-14. When Al2O3 content increased by 30 wt% and above, cleanability began to weaken, resulting in Class 1 and Class 2. The surface has become opaque with an increase in the Al2O3 content.

Low-viscosity oligoether esters (OEEs) as high-efficiency lubricating oils: Insight on their structure–lubricity relationship

Development of energy-efficient lubricants is a way to reduce energy consumption for transportation, with the tendency to design molecules that are beneficial in reducing the viscosity of synthetic oils. Oligoether esters (OEEs), as a low-viscosity ester base oil, have characteristics such as simple synthesis and excellent lubrication effect, however, the application of OEEs in tribology field has rarely been investigated. The objective of the present study is to investigate the effect of structure on the lubricating performance of OEEs and to develop a predictive model for OEEs based on quantitative structure-property relationship (QSPR) through a combination of experiment and statistical modeling. Results showed that glycol chains contribute positively to lubrication with the ether functional groups increasing the sites of adsorption. Compared to branched-chain OEEs, straight-chain OEEs exhibited reduced wear, which was mainly due to the thicker adsorption film formed by the straight-chain structure. Furthermore, carbon films were detected on lightly worn surfaces, indicating that OEEs underwent oxidation during the friction process. Based on the results of principal component analysis (PCA) and partial least squares (PLS), it could be found that the predictive models of viscosity–temperature performance, thermal stability performance, coefficient of friction (COF), and wear volume (WV) performed well and robustly. Among them, COF and WV can be best predicted with an R2 of about 0.90.

Loss of RSR1 function increases the abscisic acid content and improves rice quality performance at high temperature

Rice starch regulator1 (RSR1) participates in the regulation of starch synthesis in rice, but it's function on starch synthesis and quality formation in response to high temperature is unknown. RSR1 mutation resulted in a significant increase in the abscisic acid (ABA) content in rice grains under both normal and high temperature, and the effect of high temperature on grain filling and quality formation of the rsr1 mutants was significantly reduced. The grain size, 1000-kernels weight, amylose content, gelatinization temperature, and starch viscosity of the rsr1 mutants were less sensitive to high temperature. Loss of RSR1 function increased the expression levels of starch synthesis-related genes and reduced their responses to high temperature to some extent. Besides, the percentage of germinated seeds from rsr1 mutants was significantly lower than that of the wild-type, and the difference was more significant under ABA treatment. The shoot lengths of the rsr1 mutants were remarkably shorter than those of the wild-type, which was further exacerbated by ABA treatment. These results indicated that loss function of RSR1 can improve rice quality performance at high temperature by moderately increasing the ABA content of rice grains, which provides theoretical significance for the cultivation of better-quality rice with high-temperature resistance.