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The knowledge of fluid–particle flow behavior is necessary. Unfortunately, computational fluid dynamics (CFD) studies are mostly focused on developing numerical methods in detail. Instead, the CFD studies should also subtly shift to become a tool for digitalizing fluid science to guide the practical industrial aspects. Therefore, this simulation study intends to reveal the air and rice husk flow behaviors in a vertical suspension furnace, complete with presenting digital simulation data, aiming to alleviate the escape particle amount. According to this study, the escaped particle amount was suppressed under more sphere particle, smaller particle size, and feed inlet pipe that sunk into the burner. The properties change from rice husk to ash, along with temperature escalation (as in combustion phenomena), enlarging the escaped particle amount, so the cyclone should be installed to handle it. In addition, the results of digital turbulent data from CFD simulation have succeeded in intriguing and revealing the fluid–particle flow behavior in the vertical suspension furnace. The data show a close match to the real phenomena occurring inside this furnace which reflects the standard k–ε model can conclusively predict fluid–particle flow behavior without conflicting Newton's second law of particle motion. [ABSTRACT FROM AUTHOR]

A novel sulfated xylogalactan (JASX) was extracted and purified from the rhodophyceae Jania adhaerens. JASX was characterized by chromatography (GC/MS-EI and SEC/MALLS) and spectroscopy (ATR-FTIR and 1H/13C NMR) techniques. Results showed that JASX was constituted by repeating units of (→3)-β-d-Galp-(1,4)-3,6-α-l-AnGalp-(1→)n and (→3)-β-d-Galp-(1,4)-α-l-Galp-(1→)n substituted on O-2 and O-3 of the α-(1,4)-l-Galp units by methoxy and/or sulfate groups but also on O-6 of the β-(1,3)-d-Galp mainly by β-xylosyl side chains and less by methoxy and/or sulfate groups. The Mw, Mn, Đ, [η] and C* of JASX were respectively 600 and 160 kDa, 3.7, 102 mL.g−1 and 7.0 g.L−1. JASX exhibited pseudoplastic behavior influenced by temperature and monovalent salts and highly correlated to the power-law model and the Arrhenius relationship. JASX presented thixotropic characteristics, a gel-like viscoelastic behavior and a great viscoelasticity character. JASX showed important antioxidant activities, outlining its potential as a natural additive to produce functional foods. [ABSTRACT FROM AUTHOR]

Copyright of Advanced Textile Technology is the property of Zhejiang Sci-Tech University Magazines and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Flow behavior of three near eutectic Al–Si alloys with the same chemical composition but different average eutectic Si sizes (A1, 1.7 μm; A2, 4.4 μm; A3, 8.2 μm) was investigated by isothermal compression tests conducted on a Gleeble-3500 thermal simulator under four different temperatures (350 °C, 400 °C, 450 °C, and 500 °C) and four different strain rates (0.01 s−1, 0.1 s−1, 1 s−1, and 5 s−1), with a focus on the effect of eutectic Si size. Not only the flow behavior but also the processing map of near eutectic Al–Si alloys are affected by eutectic Si size. The overall trends of the flow stress–strain curves of the three alloys are similar, but their steady flow stresses σs are different: A1 alloy has the largest σs, followed by that of A3. Strain-compensated constitutive equations in the hyperbolic sine form were constructed to describe the flow stress behavior of the three alloys. Materials constants of the constitutive equations depend on eutectic Si size. The processing maps of the three alloys exhibit different characteristics. The instability domain of A2 alloy is restricted to strain rates larger than about 0.4 s−1, in contrast to the case of A1 and A3 alloys in which the instability domain occurs at both low and high strain rates. The results presented in this study indicate that eutectic Si size is an indispensable factor to be considered when dealing with the hot working of Al–Si alloys.

Viscosity is a physical indicator of the flow behavior of asphalt at high temperatures, and the mixing and compaction quality of asphalt mixtures depends on it; however, previous studies cannot effectively guide the application of natural rubber-modified asphalt (NRMA). In this investigation, the effects of the natural rubber latex (NRL) dose, test temperature and shear rate on the apparent viscosity of NRMA were evaluated. The results show that viscosity is approximately positively correlated with NRL dose, as described by an exponential equation that is based on Einstein's equation. Meanwhile, viscosity is negatively correlated with test temperature and shear rate, in accordance with the Arrhenius equation and power law equation, respectively. A three-factor physical equation was established to describe the relationship between viscosity and NRL dose, temperature and shear rate on the basis of the equations above, which can predict the viscosity over a wider range with limited experimental data, thereby overcoming experimental limitations. This study provides a prediction model for quickly determining the viscosity. This model is not only applicable to NRMA but also can provide references for the study of viscosity prediction for other polymer-modified asphalts.

The viscosity models for concentrated suspensions of unimodal hard spheres published in the twenty-first century are reviewed, compared, and evaluated using a large pool of available experimental data. The Pal viscosity model for unimodal suspensions is the best available model in that the predictions of this model agree very well with the low (zero)-shear experimental relative viscosity data for coarse suspensions, nanosuspensions, and coarse suspensions thickened by starch nanoparticles. The average percentage error in model predictions is less than 6.5%. Finally, the viscous behavior of concentrated multimodal suspensions is simulated using the Pal model for unimodal suspensions.

Hydraulic fracturing is a commonly adopted approach to enhance the production of unconventional reservoirs; however, the resulted complex fracture network increases the difficulty in the prediction of the flow behaviors. In this work, for the first time, we propose the Laplace-transform embedded discrete fracture model focusing on the simulation of fluid transport in simulated reservoir volume (SRV). The main hydraulic fracture is represented explicitly by the fracture segments referring to the recently developed simulation scheme, namely the embedded discrete fracture model. The equivalent model and multiple continua model are employed to characterize the fluid flow in SRV. The Laplace-transform finite-different method is used to numerically model the flow among unstimulated reservoir volume, SRV, and main hydraulic fracture with sufficient flexibility to characterize the arbitrary fracture/SRV geometries. As the solution is performed in Laplace domain, the backward Euler difference for time discretization is not necessary. Thus, the stability and convergence problems caused by time discretization are avoided. A series of numerical test cases are discussed to examine the performance of the proposed model. The simulation workflow is validated through the comparison with discrete fracture model and embedded discrete fracture model in real space. It is demonstrated that the proposed Laplace-transform embedded discrete fracture model is accurate for single flow with complex SRV distribution. On the basis of the Laplace-transform embedded discrete fracture model, we provided three applications of the new method: (1) analysis of the SRV effect on fluid flow behavior, (2) pressure transient analysis considering reservoir heterogeneity, (3) production performance analysis with time-varying production rate. [ABSTRACT FROM AUTHOR]

Microstructural evolution and flow behavior greatly affect the hot forming process of IN718. In this research, hot deformation behaviors of IN718 were investigated by performing hot compression tests at temperature range of 1000–1100 °C with strain rates of 0.1–20.0 s−1. By incorporating physically based internal state variables such as dislocation density, volume fraction of dynamic recrystallization, and grain size, a set of unified viscoplastic constitutive equations were developed to predict the microstructural evolution and flow behavior of IN718. The material constants were determined using a genetic algorithm (GA)-based optimization method. Comparisons of the computed and experimental results indicate that the constitutive equations established in this study can accurately describe the hot deformation behavior and microstructural evolution of IN718. [ABSTRACT FROM AUTHOR]

The microstructure evolution and hot deformation behavior of a Li-containing aluminum alloy AA2060 with different initial microstructure (homogenized vs. pre-rolled) were studied by isothermal hot deformation. The tests were performed within a wide range of deformation temperatures of 370–490 ℃ and strain rates of 0.01–10 s−1. Results show that the stress drop ratio of the pre-rolled specimen is higher than that of the homogenized one under the same deformation condition. Microstructure were analyzed on the thermal processing maps in unstable and optimum processing domain, and a higher dynamic recrystallization fraction can be observed in the pre-rolled specimen that has more substructures and smaller grains. Four types of the dynamic recrystallization were observed and the mechanism for deformation softening was discussed in this work. [ABSTRACT FROM AUTHOR]

High-performance heat treatable aluminum alloy sheet is widely used in aircraft and automobile industries because of its excellent mechanical properties, including low density, good corrosion resistance, and high specific strength. Many heat treatment and forming methods have been developed for aluminum alloys, such as warm stamping, hot stamping in die quenching, in order to maximize the formability, and the formed strengths. Among which, electrically assisted process (EAP) becomes attractive due to its improvement of convenience, energy saving, and efficiency. Many investigations have been published in recent decades to show that the heat treatment can be accelerated and the formability can be improved due to the thermal and non-thermal effects of electric current and tried to characterize the possible mechanisms. Hence, this paper gives a comprehensive review of the effects of electric current on the heat treatment and forming of aluminum alloy from macro- and micro-aspects. Based on this, some perspectives in developing trends of EAPs are proposed, including the mechanisms of EAP, the mechanical properties under complex stress states, and the industrial applications of EAP. [ABSTRACT FROM AUTHOR]

The aerodynamic noise behavior of flow passing the simplified leading car and nose car scale models of a high-speed train is investigated through the vortex sound theory and acoustic analogy approach. The unsteady flow developed around the geometries is solved numerically and the data are applied to study the near-field quadrupole sound source and calculate the far-field noise radiated. It is found that the turbulent flow developed around the leading car is characterized by multi-scale vortices separated from the geometries. The intensity of volume dipole source is much larger than that of volume quadrupole source and the volume dipole source becomes the predominate source of the near-field quadrupole noise. The flow is separated noticeably in the regions of the nose, bogies, bogie cavities, and train tail of the leading car where the pressure fluctuations are generated largely upon the solid surfaces and correspondingly a dipole noise of high level is produced. By comparison, the noise contribution from the leading bogie and bogie cavity is larger than that from the other components. Moreover, the numerical and experimental results of train nose car model demonstrate that the flow around the bogie region is the dominant aerodynamic sound source. Therefore, the flow-induced noise generated from the leading cars may be reduced efficiently within a certain frequency range and specific direction by mitigating the flow interactions around the areas of leading bogie and bogie cavity. [ABSTRACT FROM AUTHOR]

Tundish plasma heating could achieve constant temperature and low superheat pouring of molten steel, which is conductive for improving the efficiency of continuous casting, enhancing the internal quality of slab. The flow behavior and heat transfer of molten steel in tundish heated by plasma are essential for understanding this process. In the present study, numerical and physical simulation were conducted to investigate the temperature filed and flow characteristics of molten steel in two-strand tundish heated by plasma with different plasma heating powers. Based on the conducted simulation, it was stated that the temperature field of molten steel in tundish was significantly improved by plasma heating. The outlet temperature in 500 kW was increased by 3.05 K compared with non-plasma heating. The physical simulation demonstrated that the dead volume of tundish was reduced by 18.89% in 6 kg/h compared with non-plasma heating. The flow characteristics in the tundish with plasma heating were better than that without plasma heating. With an increase in heating power, the effect of plasma heating was considerably improved.

The present work deals with the high temperature deformation behavior of Fe-11.15Mn-5.6Al-0.07C (wt.%) triplex ferrite-based lightweight steel in the temperature range of 800–1100 °C under the strain rate of 0.001 to 0.1s−1. The compressive high temperature flow curves under the various thermomechanical conditions were accompanied by a considerable fractional softening. According to the detailed microstructural analysis, the observed flow softening was discussed relying on the occurrence of dynamic strain induced transformation and dynamic recrystallization. In this respect, a sine hyperbolic Arrhenius-type constitutive model was developed considering the three dimensional variation of the materials’ constant with strain, strain rate and temperature. This provided a proper condition for accurate assessment of the strain compensation mechanisms. The capability of the modified and un-modified constitutive models in prediction of the high temperature flow behavior of experimented low density steel were compared. According to the verified model, activation energy (Q) maps were developed and discussed in correlation with the characterized microstructure evolutions. The Q-plots were divided into three domains and a transition range was recognized at ~1100–1250 K, the extent of which decreased with increasing imposed strain. The low energy domains were attributed to the (i) activation of load transition as an effective strain compensation mechanism and the occurrence of dynamic austenite to ferrite transformation, and (ii) the high dislocation annihilation rate at high temperatures.

• A laser/ ultra-high frequency induction hybrid deposition process with embedding tube for forming deep-small hole method is proposed and experimentally validated. • A 3D numerical model coupled with electromagnetic field, temperature field, flow field and mass transport are established to investigate parametrically the effect of current intensity on the flow behavior and mass transport of the molten metal. • The dendrite type of deposited microstructure can be predicted in term of the shape control factor K, cooling rate G*R and morphological parameter G/R value distribution map. Synchronous ultra-high frequency (UHF) induction-assisted laser deposition is an effective approach to tackle the extreme heat input and common defects that originate from laser direct deposition. The added auxiliary induction heat source can reduce the energy input of the laser heat source which guarantees the geometric integrity of the embedded tube and decreases temperature gradient. Meanwhile, the effective preheating of the induction heat source assures the metallurgical bonding among the substrate, deposited track and embedded tube. Experiments showed that the effective bonding can be formed among substrate-deposited track and deposited track-embedded tube under suitable combination parameters of the laser heat and induction heat. To gain insight into the hybrid deposition, a 3D numerical model coupled with multi-physical fields was established to explore the thermal process and flow behavior with assistance of induction heat. Results indicated that the electromagnetic force produced by induction coil promotes the flow velocity, which increases heat convection. Investigation on the induction heat parameter demonstrated that raising current intensity can accelerate the flow velocity from 0.07 m s-1 to 0.09 m s-1 while the maximum temperature of the molten pool declined from 2610 K to 2440 K owing to the reinforced heat convection. The experimental cross-section of the deposited tracks and the detected element distribution in transition areas are well tested against the numerical simulation results. The grain size in the top region of the deposited track is refined with increasing current intensity, which is experimentally and numerically verified by observed microstructure and G*R value. Meanwhile, the fabricated deposited track with average friction coefficient of 0.445 can be obtained when the laser and induction parameters are 1000 W and 400A, respectively. [ABSTRACT FROM AUTHOR]

• Impact of oil on refrigerant distribution uniformity in header is summarized. • Oil retention characteristics in microchannel heat exchanger are concluded. • Mechanisms by which oil affects flow boiling are discussed. • Mechanisms by which oil affects flow cooling and condensation are discussed. • Potential future research directions are proposed. Vapor compression refrigeration and heat pump (VCRHP) systems consume large amounts of energy annually. Therefore, improving the VCRHP system efficiency holds paramount significance in pursuing the dual-carbon goal. The heat transfer performance of heat exchangers, as an essential component of the VCRHP system, has a significant impact on the VCRHP system efficiency. Compared with traditional large-size heat exchangers, microchannel heat exchangers (MCHXs) have garnered substantial attention due to their advantages, such as compact structure, high heat transfer coefficient, and small refrigerant charge. In actual VCRHP systems, oil in compressor is inevitably carried away by refrigerant. Oil can either form a mixture with refrigerant liquid, or exist as a separate oil film in various components of VCRHP system. Depending on internal geometry and operation conditions, MCHX exhibits distinct different oil retention (OR) characteristics. Oil retained in inlet header of MCHX changes the flow pattern within header and affects the pressure of downstream tube, consequently impacting refrigerant distribution characteristics. During flow boiling and cooling/condensation processes, oil changes flow behavior and heat transfer characteristics. However, previous review work has not comprehensively summarized and discussed the impact of oil in MCHX. Therefore, in this study, to provide valuable insights for assessing OR characteristics of MCHX, action mechanism of oil on refrigerant distribution behavior, and effect of oil on flow behavior and heat transfer characteristics during flow boiling and cooling/condensation, a comprehensive review of literature from the past 20 years has been conducted. Considering the limitations of current research, several potential future research directions are proposed: research on the effect of oil on flow and heat transfer in microgravity environment, design of super-oleophobic surface with nanoscale structure, optimal design of MCHX header and development of refrigerant-oil distributor, measurement of thermophysical properties and heat transfer performance of non-azeotropic refrigerant-oil mixture, as well as numerical simulation of flow and heat transfer of refrigerant-oil mixture. This review is intended to serve as a reference for the practical design and optimization of MCHX under oil-bearing conditions. [ABSTRACT FROM AUTHOR]

Thermal compression tests were conducted on Al-1.2Mg-2.4Si-1.2Cu-0.6Mn alloys with process parameters including deformation temperatures ranging from 400°C to 550°C and strain rates ranging from 0.05 s⁻¹ to 1 s⁻¹. The hot working properties of aluminum alloys were evaluated with intrinsic equations and machining diagrams. The results show that the processing safety zones of the alloy are 425–450℃ and 0.05–0.1 s−1, 450–475℃ and 0.1 s−1-0.5 s−1, and 475–500℃ and 0.5 s−1. The microstructure of the aluminum alloy following hot pressing was investigated through the use of optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and backscattered electron diffraction (EBSD). When the deformation temperature of the alloy is below 450°C, the alloy organization exhibits a greater prevalence of inhomogeneous defects, which manifest as coarser granular regions in the micro-morphology. Upon reaching a deformation temperature of above 525°C, the deformed alloy organization exhibits an evident thermal cracking phenomenon. At the same temperature, an increase in strain rate is accompanied by a decrease in the Mg 2 Si phase and an increase in the precipitation of the Al(Fe,Mn)Si eutectic phase. Furthermore, the precipitated phase tends to become coarser. The presence of certain Mn-containing nanoparticle dispersions can impede the migration of subgrain grain boundaries, while simultaneously pinning dislocations and accelerating the generation of dislocation entanglement. This also can serve to inhibit the coarsening of the grains to some extent. • Analysis of deformation mechanism by thermal compression behavior of Al-1.2Mg-2.4Si-1.2Cu-0.6Mn alloys. • The alloy is prone to defects in low-temperature deformation and thermal cracking in high-temperature deformation. • A substantial quantity of Mn-containing nanoparticles precipitate within the dislocation aggregation region. [ABSTRACT FROM AUTHOR]

The poultry processing industrial wastes are rich sources of gelatin protein, which can be utilized for various industrial sectors. The present investigation was conducted to evaluate the effect of freeze-drying (FD) and hot air drying (HAD) on the physicochemical, structural, thermal, and functional characteristics of chicken feet gelatin. The yield (%) of extracted FD and HAD gelatin was 14.7 and 14.5%, respectively. The gelatin samples showed lower percent transmittance in the UV region. The FTIR bands were at 3,410–3,448 cm−1, 1,635 cm−1, 1,527–334 cm−1, and 1,242–871 cm−1 representing amide-A, amide-I, amide-II, and amide-III bands, respectively. The water activity of HAD was higher (0.43) than in FD (0.21) samples and pH were 5.23 and 5.14 for HAD and FD samples, respectively. The flow index (n) of 6.67% gelatin solutions was 0.104 and 0.418 with consistency coefficient (k) of 37.94 and 31.68 for HAD and FD samples, respectively. The HAD sample shows higher gel strength (276 g) than the FD samples (251 g). The foaming capacity (FC) and foaming stability (FS) of FD samples were 81 and 79.44% compared to 62 and 71.28% for HAD, respectively. The emulsion capacity and emulsion stability of HAD gelatin were higher at 53.47 and 52.66% than FD gelatin. The water holding capacity (WHC) and oil binding capacity (OBC) of FD were lower, that is, 14.3 and 5.34 mL/g compared to HAD gelatin having 14.54 and 6.2 mL/g WHC and OBC, respectively. Hence, the present study indicated that gelatin samples can be utilized in various food products for enhancing functionality and can be used for developing edible packaging materials.

Phyllite bimrocks are widely distributed in the eastern margin of the Tibetan Plateau, and it is the main geomaterial for landslides, slopes, dam basement and subgrades in this area. However, the flow behavior of phyllite bimrocks is unknown, especially the flow behavior of phyllite bimrocks with the orientation of blocks. This paper reports the coupling characteristics of flow and orientation of blocks in phyllite bimrocks. The flow behavior of phyllite bimrocks with different block percentages and block sizes was studied by a series of permeability experiments. A large-scale permeability apparatus was designed, and specimens with varying percentages of block and block sizes were produced by the same dip angle of blocks and compaction degree. Based on the Reynolds number analysis, it was found that the flow in phyllite bimrocks becomes laminar to turbulent under lower hydraulic gradient, and the flow behavior of phyllite bimrocks does not obey Darcy’s law. Furthermore, the Forchheimer equation is better at analyzing the flow behavior of phyllite bimrocks compared with Izbash equation. In addition, based on the coefficients a in the Forchheimer equation, the hydraulic conductivity of phyllite bimrocks can be calculated. The calculation result shows that when the percentage of blocks is 25%, the hydraulic conductivity reaches the minimum. Besides, the hydraulic conductivity increases approximately linear with the block size increase. On the basis of previous studies, coefficients A and B of the Forchheimer equation are detected by the normalized objective function analysis. The results would provide a valuable reference for risk assessment and prevention of phyllite bimrock slope.

Under the condition of strain rates of 0.001–1 s−1 and temperatures of 473–723 K, the flow behaviors of the cast-homogenized ZK10 magnesium alloy were studied through the isothermal compression test with final true strain of 1. In view of this, the Arrhenius equation subject to strain was treated with a comprehensive correction, the deformation activation energy Q of ZK10 alloy was calculated to be 181.87 kJ/mol, and a reliable flow stress model of ZK10 alloy was established. Meanwhile, the processing maps and microstructure evolution of ZK10 alloy were analyzed, which indicated that obvious dynamic recrystallization occurred during thermal compression deformation of ZK10 alloy under the above process conditions. When ZK10 alloy was hot compressed at 473 K in the instability zone, serious instability deformation and macro cracks occurred at strain rates of 0.001 s−1 and 0.01 s−1. The optimum process parameter of ZK10 alloy under the experimental conditions was obtained to be 673 K/1 s−1, and the corresponding microstructure was the most uniform and finest, which provides useful guidance for the selection of process parameters of ZK10 alloy.

The simultaneous occurrence of phase transformation and deformation for titanium alloy sheets is an important feature in hot stamping process where components are formed in room-temperature tools by hot blanks. This work takes a research on the constitutive modeling of TA15 alloy by coupling the effect of phase transformation under hot stamping conditions. Based on Gleeble testing system, the continuous cooling tests and interrupted tensile tests are conducted to study the effects of cooling rate and deformation on phase transformation. Subsequently, a diffusion controlled phase transformation model is extended to describe the phase transformation kinetics. The flow behaviors of TA15 alloy are found to be not only sensitive to temperature and strain rate, but also cooling rate dependent, which can be ascribed to the phase transformation. Hence, a physically based model coupling the effect of phase transformation is proposed. Compared with experimental stress–strain values, the average relative error of predicted results by the proposed model is 2.29%. Finally, hot stamping simulations and experiments of a U-shape part are performed. The simulation results of the proposed model show a better agreement with the experiments.

• The release kinetics under temperature trigger follows the Ritger-Peppas model. • The fluid undergoes a granular-to-non-Newtonian fluid transition with time. • Microencapsulated polymer particles stabilize shear and improve oil displacement. • Higher trigger degree inhibits fluid fingering and improves sweep efficiency. Due to the challenges posed by high injection pressure and significant viscosity shear loss, conventional polymer flooding methods are unable to effectively meet the urgent demand for enhanced oil recovery in medium- and low-permeability reservoirs. Microencapsulated polymer flooding is a promising solution to address the aforementioned challenges due to its advantages of easy wellbore injection, shear resistance, and delayed thickening. However, there is a lack of research on the release behavior and time-dependent characteristics of microencapsulated polymer and its impact on flow behavior in reservoirs. To address this gap, we conducted a series of experiments, including thermal stability tests, microfluidic chip experiments, and micro-scale oil displacement experiments, to reveal the time-varying behavior generated by the triggered release of microencapsulated polymers. The results showed that microencapsulated polymer can be fully triggered after 8 days of aging at 85 °C, with a viscosity exceeding the initial viscosity by more than 25 times. The release mechanism of the polymer aligned with the Ritger-Peppas model, transitioning from super Case-II transport to anomalous transport, and finally to Fickian diffusion with increasing temperature. During the triggering process, the presence of particles stabilized shear and improved oil displacement, particularly in small pore throats. Higher triggering degrees of the solution resulted in greater flow resistance within the microchannel, effectively suppressing fluid fingering. The oil displacement effectiveness of fully triggered microencapsulated polymer was comparable to that of conventional polymers. This study provides insights into the flow behavior of microencapsulated polymer at a microscopic level, offering valuable references for its application in the field. [ABSTRACT FROM AUTHOR]

[Display omitted] • The flow behavior, d 32 , and ɛ g of microbubble swarm were investigated under different packed structures of catalyst bed and catalyst support bed. • An empirical correlation would be established to predict (d 32) o /(d 32) i. • The mass transfer parameters, such as the microbubble number density (MND) and effective interfacial area (a e) of HFBR, were also obtained. A HiGee-aided fixed bed reactor (HFBR) has great potential for catalytic hydrogenation with hydrogen microbubble swarm for gas–liquid mass transfer intensification. However, the flow behavior and size characteristics of microbubble swarm in the catalyst bed of HFBR still remain unclear. In this work, the flow characteristics of microbubble swarm in different packed structures of catalysts and catalyst supports had been fully analyzed by the high-speed photography and image processing technology. The optimal ratio of packing heights for the bottom of the catalyst supports was Φ 13 mm: Φ 6 mm: Φ 3 mm = 3: 1: 1, while the top of the catalyst supports was packed with single catalyst support of Φ 6 mm. Furthermore, a dimensionless correlation based on the experimental results had been developed to predict (d 32) o /(d 32) i with deviations within ±15 %. The effective interfacial area of HFBR was 0.6 ∼ 6.1 × 103 m2/m3 under the experimental conditions. [ABSTRACT FROM AUTHOR]

To investigate the dynamic recrystallization (DRX) behavior of as-cast Fe-20Cr-5.5Al-0.64La stainless steel, a series of compression tests were carried out on a Gleeble-3500 thermal simulator in the temperature range of 1000~1150 °C and the strain rate range of 0.001~1 s−1. The true stress-true strain curves were obtained and their characteristics were analyzed. Using regression analysis, the apparent activation energy for the Fe-20Cr-5.5Al-0.64La stainless steel was estimated to be 300.19 kJ/mol, and the constitutive equation was developed successfully with a hyperbolic sine equation as: ε˙=e21.91sinh0.035σ3.18exp−300190RT. The critical strain, the peak strain and the strain for the maximum softening rate were identified based on the work hardening rate curves and expressed as a function of the Zener−Hollomon parameter. The kinetic model of DRX was established using the stress−strain data. According to the analysis of the kinetics model and microstructure evolution, the evolution of DRX volume could be described as follows: the volume fraction of DRX grains increased with an increase in strain; at a fixed deformation temperature, the DRX volume fraction was larger at a lower strain rate for the same strain; and the size of DRX grains increased with an increase in temperature or a decrease in strain rate.

We develop the direct laser melting of ceramic paste technology for application in ceramic additive manufacturing (AM). The Al 2 O 3 ceramic paste, which is a homogeneous mixture of DI-water and Al 2 O 3 ceramic powders, was deposited on an Al 2 O 3 substrate using free-forming extrusion (FFE), and subsequently melted by a CO 2 laser. To better control the laser melting process, the flow behavior of the laser-melted Al 2 O 3 was investigated by evaluating the microstructure of the laser-melted Al 2 O 3 single tracks. When the laser scanning speed increased from 1 to 3.5 mm/s at a fixed laser power, the permeation of the molten Al 2 O 3 into the surrounding porous paste was reduced, resulting in the improvement of the surface uniformity of the laser-melted Al 2 O 3 tracks. Through optimizing the laser scanning strategy, a fully-dense Al 2 O 3 layer with smooth surface was achieved. The phase composition and density of the laser-melted Al 2 O 3 layers were evaluated to study their properties. The thickness of the dense Al 2 O 3 layer varied from ∼90 μm to ∼120 μm periodically due to the line-by-line scanning of the Gaussian laser beam. In addition, the relationship between the melting thickness and the laser scanning speed was also investigated to further improve the controllability of the laser melting process. This direct laser melting of ceramic paste technology is promising for applications in ceramic AM, such as 3D printing of ceramic components and high-temperature ceramic welding. [ABSTRACT FROM AUTHOR]

An air curtain machine is used in the entrances and exits of public places where air conditioners are used. The high-speed centrifugal or axial fan blows out the air, creating an airflow barrier to prevent air convection inside and outside, reducing air conditioning losses, and maintaining the indoor air quality by preventing dust, insects, and harmful gases from entering the room. Observation of the airflow behavior was conducted using CFD simulation, to explore whether it has a blocking effect, and the air curtain principle was applied to the air purification equipment. It is mainly composed of several rows of arrayed hole air outlets to form a multi-composite air wall. The airflow on the two sides, or below, can be blocked by the composite air wall and integrated into the main airflow, so that the air walls will not affect each other, and form a barrier effect to prevent infection. This research includes the measurement of impedance characteristics for three layers of filters made of different materials. These filters are used as the input characteristic parameters in the simulation analysis. Four scenarios are discussed, including the consultation room, hospital ward, quarantine station, and conference room. From the simulation results, it is known that when there are many people, the equipment can be set to high speed to increase the volume of air, forming a wind wall to effectively block airflow from the people in the chairs, reducing the risk of infection. Note that the rotation speed should not be too high. The air outlet equipment is susceptible to turbulent flow, which will make the airflow deviate from the expected direction and increase the possibility of mutual infection between adjacent people. Partitions can be used to block airflow to reduce the risk of infection. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this study was to determine the composition, antioxidant activity and rheological characteristics of spreadable pastes with blackberry pulp (BP) containing cream (C) or cream cheese (CC). Spreadable pastes were prepared in different ratios (1:3, 1:1, and 3:1, w/w). When the amount of blackberry pulp is greater in spreadable pastes containing cheese or cream cheese, the contents of dry matter, lipids, protein, and ash are minor, due to the composition of the blackberry pulp. The antioxidant activity was determined by ABTS [2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt] and DPPH (2,2-diphenil-1-picrylhydrazyl) assays. The results indicate that when the proportion of blackberry pulp is greater in spreadable pastes, the antioxidant activity increases in a range of 43.51–44.50%, using the Trolox equivalent antioxidant capacity (TEAC) method. Spreadable pastes presented pseudoplastic non-Newtonian behavior, with n < 1. In general, the apparent viscosity was greater in spreadable pastes BP-CC than in BP-C. Spreadable pastes showed a predominance of the elastic component G′ > G″. The creep curves presented a recovery between 56.0 and 86.2% for BP-C and between 66.3 and 85.0% for BP-CC, indicating viscoelastic solid behavior. The viscoelastic behavior of pastes was adjusted by the Burgers model with a Kelvin-Voigt element. The rheological properties and antioxidant activity of spreadable pastes can increase interest in characterizing them as functional and health foods. [ABSTRACT FROM AUTHOR]

The flow behavior of a Ti-6Al-4V alloy has been investigated and modeled, with the aim of exploring the damage mechanism and distortion of a sandwich structure during the air cooling process after superplastic forming (SPF). The selected temperature range was 930–700 °C, and the strain rates were 10−2, 10−3, and 10−4/s. An Arrhenius model was employed to describe the yield stress at a strain of 0.1, and a simple generalized reduced gradient refinement was applied to optimize the parameters for a constitutive model. The mean error between the predicted and experimental flow stress was 65% and 16% before and after parameter optimization, respectively. The effects of strain on flow stress showed a linear relationship, so a strain compensation method was proposed. The modified Arrhenius model developed in this paper provided a good agreement between the predicted stresses and the experimental data. Finally, a finite element analysis (FEA) with a "UHARD" subroutine was employed, and the results indicated that the inner plate of the sandwich structure was the most vulnerable location during the air cooling process, and that the engineering strain due to a non-uniform temperature was calculated as 0.37%. [ABSTRACT FROM AUTHOR]

Use Gleeble-1500D thermal simulation test machine to conduct thermal tensile test on AISI 1035 in the deformation temperature range of 1 173,15~1 373,15 K and strain rate range of 0,2 ~ 20 s-1. Using the obtained true stress-strain curves, an intrinsic model of the material was constructed using a model considering strain compensation. The results showed that the correlation coefficient of the Arrhenius model of AISI 1035 considering strain compensation was 0,984 with an average absolute error of 3,550 %, which can accurately predict the flow profitability. The experimental data matched well with the prediction curves obtained from the model calculation, which verified the feasibility of the model.

Protein functional properties are related to physical and chemical parameters that influence protein behavior in food systems during processing, storage and consumption. The structural and rheological properties of three quinoa hyperprotein flours (without defatting, WD, chemically defatted, CD, and mechanically defatted, MD) were evaluated. The values of the fluidity index (n) were significantly different (p < 0.05), which was associated with changes in protein or starch structures due to solvent treatments or heating of the flour during pressing. In addition, a strong dependence of the consistency index (k) on the shear rate was observed. For dispersions with a concentration of 12% (w/v), CD and WD had a significantly lower setback value than MD. The viscosity peak was affected by the presence of lipid molecules. Greater changes were evident in the β-sheet (1,610 and 1,625 cm−1) and β-spin (1,685 and 1,695 cm−1) structures. The changes identified in these structures were associated with the defatting treatment. Consequently, the intensity ratio 2,920/1,633 cm−1 was more sensitive to changes in the fat content of the flours. It was shown that defatting conditions increase the protein adsorption kinetics and that the viscoelastic properties of the protein increase when the flour has a lower fat content. Hyperprotein quinoa flour could be used to improve the protein content of products such as snacks, pastas, ice cream, bakery products, meat extenders, among others, due to its foaming, gelling or emulsifying capacity. The objective of this work was to study the effect of two types of defatting of hyperprotein quinoa flour on its structural and rheological properties.

Hot compression behaviors of CrCoNi medium entropy alloy are were performed on the Gleeble-3800 thermal simulator in the strain rate range from 0.01 to 10 s−1 and the temperature range from 800 to 1100 °C. According to the true stress-true strain curves, the true stress decreases with the decreasing of strain rate and the increasing of deformation temperature. The experimental parameters were fitted, and a modified model based on Arrhenius hyperbolic sine was established. Among them, material constants such as, n, A, and Q are functions of strain. Meanwhile, the processing map of CrCoNi medium entropy alloy under different strain conditions are established. Importantly, the optimal domain of apparent flow stability can be determined as the deformation temperature from 900 to 1100 °C and the strain rate from 0.01 to 10 s−1. The results indicate that the stability domain of the CrCoN medium entropy alloy has a wider range, and the strain has little effect on its processing performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Spinneret's flow angles and power-law indices are critical variables that can enhance the shear rate of dope solution. • The trends of dimensionless velocity, shear rate, and viscosity distributions have not changed significantly with flow rates. • The low shear rate gradient prevalence elevates the viscosity in the annular spinneret region. • There is a possibility of producing finger-like macrovoids near the outer/inner membrane layer. We employed the computational fluid dynamics (CFD) simulation to capture the flow behavior in spinnerets based on various flow angles (90°, 75°, 60°, and 30°), different power-law fluids (0.5 ≤ n ≤ 1), and two different flow rates (0.2 mL/min and 1.4 mL/min). The simulation results moderately agreed with the semi-analytical solution obtained from the literature. The sensitivity analysis was performed, showing that spinneret's flow angles and power-law indices are additional critical variables that facilitate the alignment of the polymeric chain in the dope solution due to the enhanced shear rate. The maximum viscosity reduction is observed in this study when a more shear-sensitive dope fluid extrudes through the spinneret at a given flow rate. The low shear rate gradient prevalence elevates the viscosity in the annular spinneret region, strongly dependent on the flow and shear-sensitive fluid (n < 1). The trends of dimensionless velocity, shear rate, and viscosity distribution are independent of the dope solution flow rates at the exit of a spinneret except for the more shear-sensitive fluids at 60° flow angle spinneret. We attempted to correlate the shear rate and viscosity distributions of the dope solution at the exit of the spinneret with the literature finding on the hollow fiber morphology under wet spinning conditions. It shows a possibility of producing finger-like macrovoids near the outer/inner membrane layer while extruding the hollow fiber through straight/conical spinneret due to relatively low shear rate and lower viscosity region. [ABSTRACT FROM AUTHOR]

In this work, the effects of cryogenic cycling rejuvenation on the flow behavior of ZrCuAlNiAg metallic glass (MG) in the range of relaxation region from 0.7 up to 0.9 glass transition temperature (Tg) were investigated. For this purpose, nanoindentation and strain-rate jump tests were carried out to show the strain response of glassy alloy. According to the jump test, the increase in applied temperature leads to the rise in induced strain in both of as-cast and rejuvenated samples. It was also uncovered that the rejuvenated sample is sensitive to the higher strain rates leading to the significant overshoot in the flow stresses. In addition, the nanoindentation results indicated that the loading process induced a significant anelastic strain in the rejuvenated sample at 0.9Tg, demonstrating the possible formation and percolation of shear transformation zones (STZs) in the rejuvenated amorphous structure. [ABSTRACT FROM AUTHOR]

In this study, the hot deformation behavior of an as-cast and hot rolled β21S alloy (Ti–15Mo–3Al–3Nb–0.2Si) was investigated. Based on the hot compression tests, which were conducted at high temperatures (800–1200 °C) using different strain rates (10−2 –10 s−1), a processing map and energy efficiency (η) value were obtained for the alloy. Furthermore, the deformation activation energy of the alloy was calculated and the tensile properties of the alloy after the thermal treatment were analyzed. The processing map results revealed that plastic instability occurred at a temperature of 900 °C and a strain rate of 10 s−1. Over the entire temperature range the hot deformation mechanisms indicated an activation energy of 269 kJ/mol and the ln Z values, calculated by the Zener-Holloman parameter, varied between 17 and 32 s−1, in which the stable flow was associated with dynamic recovery and dynamic recrystallization. Likewise, this study revealed that dynamic recovery is the dominant deformation mechanism in the β21S alloy at temperatures lower than 1000 °C, while dynamic recrystallization is prevalent at higher temperatures. Finally, the tensile properties of the β21S alloy depend significantly on the post-processing heat treatment. The rapid grain-growth phenomenon observed at 1200 °C suggests that the practical alloy rolling conditions may differ from that used for hot compression tests performed in the laboratory. These results demonstrate that the process optimization is significantly dependent on sample size which affects soaking time.

Introduction: Antimicrobial compounds have recently attracted the attention of researchers across the world. Essential oils (EOs) could be used as potent herbal antimicrobial materials and natural antioxidants in the food industry. The present study aimed to assess the effects of Rosmarinus officinalis essential oil (REO) with variable phenol contents on the properties of probiotic yogurt containing Bifidobacterium bifidum. Methods: Yogurt was prepared by adding Lactobacillus bulgaricus and Streptococcus thermophilus as the starter and the Bifidobacterium bifidum as the probiotic strains. REO was also added at the three concentrations of 1%, 2%, and 3%. Titratable acidity, pH, syneresis, and rheological, microbial, and sensory properties were evaluated at three storage times (7, 14, and 21 days). The total phenol content was approximately 8.93±0.11 milligrams of gallic acid. Results: The bacterial activity significantly declined in all the samples during 20 days of storage (PConclusion: According to the results, high levels of phenolic compounds contributed to the biological, physicochemical, and rheological properties of probiotic yogurt, as well as its sensory scores.

In order to study the effect of deformation parameters on the flow stress of EH40 steel plate during hot working,using Gleeble-3800 tester to perform thermal compression simulation of specimen,the true stress-strain curve of EH40 shipboard steel under temperature conditions of 0. 1 s-1～ 10 s-1 strain rate and 900℃ ～ 1 200℃ is obtained. By analyzing the curve,we find that deformation temperature and strain rate all have important effects on the dynamic recrystallization and dynamic recovery of EH40 plate steel,increasing the deformation temperature or reducing the strain rate is conducive to the occurrence of dynamic recrystallization during deformation,which contributes to grain refinement of the material. A hyperbolic sine model with ZeneHollomon parameters is adopted,the thermal deformation equation,activation energy of thermal deformation,and mathematical model of Z parameters were obtained. It is verified that the average error between the calculated value and the experimental value of the established constitutive relation is 3. 13%,which can well reflect the actual hot deformation behavior of EH40 ship-board steel.

In this paper, the hot tensile deformation of a GH3230 superalloy double-sheet was conducted under deformation temperatures ranging from 1123~1273 K and strain rates ranging from 0.001~0.2 s−1. The flow behavior of the GH3230 superalloy double-sheet was analyzed in detail. The hot tensile deformation process of the GH3230 superalloy double-sheet includes four stages of elastic deformation, strain hardening, steady state and fracture. The true stress decreases with the increasing deformation temperature and decreasing strain rate. The variation of the strain rate sensitivity index and strain hardening index with processing parameters were discussed. The average apparent activation energy for hot tensile deformation is 408.53 ± 46.96 kJ·mol−1. A combined Johnson-Cook and Hensel-Spittle model considering the couple effect of strain hardening, strain rate hardening and thermal softening was established to describe the hot tensile behavior of the GH3230 alloy double-sheet. Compared to Johnson-Cook model and Hensel-Spittle model, this model has the highest predicting accuracy. The average absolute relative error of true stress between the experimental and the predicted is only 2.35%.

Abstract Asphaltene is a component of crude oil that has been reported to cause severe problems during production and transportation of the oil from the reservoir. It is a solid component of the oil that has different structures and molecular makeup which makes it one of the most complex components of the oil. This research provides a detailed review of asphaltene properties, characteristics, and previous studies to construct a guideline to asphaltene and its impact on oil recovery. The research begins with an explanation of the main components of crude oil and their relation to asphaltene. The method by which asphaltene is quantified in the crude oil is then explained. Due to its different structures, asphaltene has been modeled using different models all of which are then discussed. All chemical analysis methods that have been used to characterize and study asphaltene are then mentioned and the most commonly used method is shown. Asphaltene will pass through several phases in the reservoir beginning from its stability phase up to its deposition in the pores, wellbore, and facilities. All these phases are explained, and the reason they may occur is mentioned. Following this, the methods by which asphaltene can damage oil recovery are presented. Asphaltene rheology and flow mechanism in the reservoir are then explained in detail including asphaltene onset pressure determination and significance and the use of micro- and nanofluidics to model asphaltene. Finally, the mathematical models, previous laboratory, and oilfield studies conducted to evaluate asphaltene are discussed. This research will help increase the understanding of asphaltene and provide a guideline to properly study and model asphaltene in future studies.

This paper focuses on the influence of volume change boundary condition on the instability and post-peak softening of sand. The laboratory program comprises an extensive series of Direct Simple Shear (DSS) tests with different degrees of linear coupling between volumetric and shear strains. It is observed that progressive loosening of sand associated with the volumetric expansion in a coupled strain path intensifies instability susceptibility, whereas volumetric contractive strains reduce vulnerability to instability and post-peak softening. Analysis of the experimental data using Hill's second-order work criterion designates a family of state-dependent relational trends for instability lines, normalized peak shear strengths, and maximum pore-water pressure ratios depending on the degree of coupling between the volumetric and shear strain rates. It is found that a simple state-dependent constitutive model can predict relational trends in sand specimens suffering from instability and post-peak softening under different degrees of the linear coupling between the volumetric and shear strains. [ABSTRACT FROM AUTHOR]

The gas–liquid–solid three‐phase moving beds could supply a potential solution for multiphase reactions with catalyst easily deactivated, and the flow regimes in it were studied by optical method and pressure drop measurement. Results showed that taking the trickle flow as the initial flow regime, the flow channels were more obvious as the particle velocity increased. When the initial flow regimes were pulse flow and bubble flow respectively, the pulse‐to‐trickle and bubble‐to‐pulse flow transitions mainly occurred at moderate‐to‐high particle velocities (0.01–0.04 m s−1 under conditions used in this work). Moreover, the flow regime map in the three‐phase moving bed was constructed and shown that the region of trickle flow increased and the region of bubble flow decreased. Finally, the application of three‐phase moving beds was discussed, and it could be suitable for those reactions, which had to operate in the pulse flow, bubble flow, and transition zone. [ABSTRACT FROM AUTHOR]

Pineapple leaf waste, with its high cellulose content, can serve as alternative starting material for the production of carboxymethyl cellulose (CMC). In this study, synthesis conditions of CMC from pineapple leaves via the use of microwave heating were optimized. Box-Behnken design and response surface methodology were applied to schedule the experiments and to optimize the synthesis condition, respectively. Preparation of CMC was investigated by varying three factors, namely, sodium hydroxide (NaOH) concentration, monochloroacetic acid (MCA) dose, and etherification time. The process of carboxymethylation was optimized to produce CMC with high degree of substitution (DS). Optimal condition for CMC synthesis was noted to be 50% (w/v) NaOH solution, 8 g of MCA/g cellulose, and etherification time of 16 min; such optimal condition resulted in the maximum DS of 0.78. Synthesized CMC was utilized as a thickener for liquid foods (water, orange juice, milk, and mushroom cream soup) where 2% (w/v) as-synthesized CMC increased the viscosity of the foods and changed their characteristics from thin to nectar-like liquids. [ABSTRACT FROM AUTHOR]

In this work, basalt fibers (BF) have been investigated as possible natural and sustainable replacements for the common synthetic mineral filler—glass fibers (GF)—used in polyamide 66 matrix (PA66). Composites have been prepared at two different fiber concentrations (15 and 25 wt.%, respectively) by melt blending. The developed systems have been mainly characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), capillary rheology, and scanning electron microscopy (SEM). The kinetic parameters to thermal degradation through the Coats–Redfern method allowed us to attest a negligible effect of fiber type on thermal stability of the developed systems. Composites incorporating 15 wt.% of fiber content possessed the highest activation energy (≥230 kJ/mol). The introduction of BF and GF in PA 66 polymer, regardless of content, always led to an increase in crystallization and melting temperatures, and to a similar reduction in crystallinity degree and glass transition temperature. The shear viscosity of the basic polymer increased by the addition of fillers, particularly at low shear rate, with a pronounced effect in the case of basal fibers. A slightly higher shear thinning behavior of BF/PA66 with respect to GF/PA66 composites was confirmed by fitting the flow curves through the power law model. Finally, a worsening in fiber dispersion, by increasing the content in the matrix, and a weak compatibility between the two phases constituting the materials were highlighted through SEM micrographs.