Two-step Heating Research Articles

Regulating heat-induced fibrous whey protein-wheat starch composite emulsion gels as dysphagia food by preheating temperature: Insights from protein-starch interactions

Heat-induced processes significantly affect the gel behavior of protein and starch, but the mechanism by which preheating temperature affects the quality characteristics of the gel is unclear. Herein, to explore the feasibility of developing texture-modified foods based on proteins, carbohydrates and lipids, the effects of preheating temperatures (40–80 °C) on the texture and starch digestibility of fibrous whey protein (FWP)-wheat starch composite emulsion gels (CEGs) under two-step heating condition were investigated. The rheological and texture properties, protein-starch interactions and microstructure of CEGs were characterized. The results showed that preheating temperature synchronously regulated the texture and starch digestibility of heat-induced CEGs. When preheating temperature is below 60 °C, two-step heated CEGs showed bicontinuous networks with harder texture, similar as one-step heated gels. While temperature exceeds 60 °C, preheating altered FWP conformation and promoted protein-starch interactions, forming protein-starch complexes or protein aggregates. This changed protein distribution and disrupted bicontinuous network, forming more hydrophobic interaction, yielding a soft-textured CEGs. In this case, SDS content increased and RS content decreased. Notably, two-step heating process with high preheating temperature (>60 °C) is universal for softening fibrous whey protein-starch-based composite gels. This study enhances the understanding of traditional heat-induced protein-starch gelation processes and provides a simple and feasible method for developing texture-modified foods.

Transient Liquid Phase Bonding by Two-Step Heating Technique of IN939

Transient Liquid Phase Bonding by Two-Step Heating Technique of IN939

Ultralight reduced graphene oxide based foam with excellent electromagnetic interference shielding and superior mechanical properties

Reduced graphene oxide/carboxymethyl cellulose (RGO/CMC) foams with ultra-lightweight, excellent EMI shielding and mechanical robustness are fabricated based on a facile solution method and regulation of thermal reduction conditions. Results indicate that the two-step heating mode is good to obtain better EMI shielding properties. By introducing only 10 wt% of CMC, high electrical conductivity up to 34.7 S/m and EMI shieling effectiveness (SE) up to 34.6 dB are obtained. In addition, due to the connection effect of CMC, superior compressive strength and modulus as high as 8.3 KPa and 29.2 KPa are achieved, corresponding to an increase of 388.2% and 378.7%, respectively, compared to that of the RGO foam without CMC. Moreover, due to the ultralow density (∼4.1 mg/cm3) and high EMI SE of RGO/CMC, excellent specific shielding efficiency as high as 42195 dB.cm2/g is obtained, way much superior to that of other metal-, graphene-, and CNT-based carbon foams. This work will have great significance for facile fabricating efficient EMI shielding materials towards electronics and aerospace applications.

Unravelling formation mechanism, thermal and oxidation stabilities of layered sub-micron MAB phase WAlB synthesized at open atmosphere

With the high melting point, good thermal and electrical conductivities, a less explored layered MAB phase WAlB may prove beneficial for futuristic applications. In this present paper, a successful synthesis method of highly pure WAlB phase under an open atmosphere following the molten salt route is reported. In this method, a two-step heating profile was used to produce sub-micron sized particles. Template growth of layer WAlB from layered W–Al intermetallics is revealed after careful examination using XRD, SEM, and thermal analysis. The WAlB phase was found thermally stable until 800 °C under an inert atmosphere and until 500 °C under an open atmosphere after investigating the respective XRD, thermal analysis, and SEM data.

Two-step Heating Effect of Hydrochar-MnO_2 Formation and Their Electrochemical Performances

Two-step Heating Effect of Hydrochar-MnO_2 Formation and Their Electrochemical Performances

A two-step strategy for the preparation of ultra-small Mn3O4 @C anode for lithium-ion batteries

Nano-engineering and hybrid with carbon are effective methods for improving the electrochemical performance of Mn3O4 anodes. However, there are many difficulties in further reducing the size of Mn3O4. To solve these challenges, a novel hollow microsphere structure constituted of ultra-small Mn3O4 nanoparticles (less than 5 nm) embedded within ultrathin carbon nanosheets is designed as anode materials by a simple two-step heating treatment method. The ultra-small Mn3O4 nanoparticles will accelerate the kinetic reaction process and relieve volume variation. Meanwhile, In-situ fabrication of conductive carbon nanosheets play an important role in the electronic/ion transfer and the structure stability. Due to the synergistic effect of ultra-small Mn3O4 nanoparticles and carbon nanosheets, the material shows a topmost reversible capacity of 804 mAh g−1 at the current density of 1 C and maintains a high specific capacity of 603 mAh g−1 after 700 cycles. The strategy can be extended to prepare of other functional nanoparticles and apply in energy storage and catalysis.

Effect of Oxidative Synthesis Conditions on the Performance of Single-Crystalline LiMn2- x Mx O4 (M = Al, Fe, and Ni) Spinel Cathodes in Lithium-Ion Batteries.

LiMn2 O4 (LMO) spinel cathode materials attract much interest due to the low price of manganese and high power density for lithium-ion batteries. However, the LMO cathodes suffer from the Mn dissolution problem at particle surfaces, which accelerates capacity fade. Herein, the authors report that the oxidative synthesis condition is a key factor in the cell performance of single-crystalline LiMn2- x Mx O4 (0.03 ≤ x ≤ 0.1, M = Al, Fe, and Ni) cathode materials prepared at 1000 °C. The use of oxygen flow during the spinel-phase formation minimizes the presence of oxygen vacancies generated at 1000 °C, thereby yielding a stoichiometrically doped LMO product; otherwise, the spinel cathode prepared in atmospheric air readily loses capacity due to the oxygen vacancies in the structure. As a way of circumventing the use of oxygen flow, a one-pot, two-step heating in air at 1000 °C and subsequently at 600 °C is used to yield the stoichiometric LMO product. The lithiation heating at 1000-600 ⁰C resulted in a significant improvement in the cycling stability of the prepared LMO cathode in graphite-based full cells. This study on oxidative synthesis conditions also confirms the advantage of minimizing the surface area of the cathode particles.

Quantitative analysis of acrylic acid in acrylic pressure-sensitive adhesives by reactive pyrolysis-GC/MS using N,O-bis(trimethylsilyl)trifluoroacetamide as a trimethylsilylation reagent with two-step heating

Acrylic pressure-sensitive adhesives (APSAs) have been used in a variety of fields and the composition of their monomers is a very important factor in determining their physical properties. Monomers containing polar functional groups, such as acrylic acid (AA), are often used as raw materials for APSAs, and the number of these monomer units in the polymer chain has a significant effect on the adhesive properties. However, due to its high reactivity and polarity, it is not easy to accurately quantify AA in APSAs by conventional reactive pyrolysis gas chromatography mass spectrometry (Py-GC/MS). In this study, quantitative analysis of AA in APSAs was examined by reactive Py-GC/MS using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) as a trimethylsilylation (TMS) reagent (Py (BSTFA)-GC/MS). First, the APSA sample was mixed with BSTFA and heated at 60 ºC for 30 min to accelerate TMS derivatization of any unpolymerized AA monomers (AA-TMS). If unreacted BSTFA remains after derivatization, it will react with AAs produced by the pyrolysis of acrylic ester units. These additional AA monomers,will results in the over-estimation of the true amount of unpolymerized AA monomers. To prevent this undesirable effect by residual reagent, the TMS-derivatized sample was further heated at 100 ºC for 10 min before pyrolysis in order to remove residual BSTFA and solvent. The derivatized sample was measured by Py-GC/MS at 600 ºC and the relative standard deviation of the peak area ratio of AA-TMS derived from unpolymerized AA monomers to the internal standard (anthracene-d10) was less than 5% (n = 5). In the calibration curves made for four APSA samples with known compositions, good linearity was obtained for the raw materials of butyl acrylate and 2-ethylhexyl acrylate in addition to AA-TMS. Quantitative analysis of AA monomers in a commercial APSA sample showed fairly good agreement with the amount of AA determined by the official method of analysis using the acid-base titration (JIS K 5601–2–1). The results obtained in this study indicate that Py (BSTFA)-GC/MS is effective for the compositional analysis of APSAs.

Fast pressureless solid-state reaction sintering of highly infrared transparent MgAlON ceramics from MgAl2O4 and AlON powders by two-step heating

Fast pressureless solid-state reaction sintering of highly infrared transparent MgAlON ceramics from MgAl2O4 and AlON powders by two-step heating

Fractionalized Prethermalization in a Driven Quantum Spin Liquid.

Quantum spin liquids subject to a periodic drive can display fascinating nonequilibrium heating behavior because of their emergent fractionalized quasiparticles. Here, we investigate a driven Kitaev honeycomb model and examine the dynamics of emergent Majorana matter and Z_{2} flux excitations. We uncover a distinct two-step heating profile-dubbed fractionalized prethermalization-and a quasistationary state with vastly different temperatures for the matter and the flux sectors. We argue that this peculiar prethermalization behavior is a consequence of fractionalization. Furthermore, we discuss an experimentally feasible protocol for preparing a zero-flux initial state of the Kiteav honeycomb model with a low energy density, which can be used to observe fractionalized prethermalization in quantum information processing platforms.

Study on Hardness of Heat-Treated CoCrMo Alloy Recycled by Electron Beam Melting.

The hardness of heat (thermally) treated CoCrMo ingots, recycled by electron beam melting and refining (EBMR) of a technogenic CoCrMo material (waste from the dental technology) under different process conditions (temperature and residence time) is examined. The heat treatment consists of two-step heating up to temperatures of 423 K and 1343 K and retention times of 40 and 60 min, respectively. The influence of various loads (0.98 N, 1.96 N, 2.94 N, 4.9 N, and 9.8 N) on the hardness of the CoCrMo alloy, recycled by EBMR, before and after heat treatment is studied. It has been found that regardless of the EBMR process conditions, the obtained samples after heat treatment have similar hardness values (between 494.2 HV and 505.9 HV) and they are significantly lower than the hardness of the specimens before the heat treatment. The highest hardness (600 HV) is measured in the alloy recycled at 1845 K refining temperature for 20 min. This is due to the smaller crystal structure of the resulting alloy and the higher cobalt content. The results obtained show that the heat treatment leads to considerable changes in the microstructure of the CoCrMo ingots recycled by EBMR. With the increase of the e-beam refining temperature, after the heat treatment, the grains' size increases and the grains' shape indicates an incomplete phase transition from γ-fcc to ε-hcp phase. This leads to a slight increase in the hardness of the alloy.

A Two-Step Heating Strategy for Nonhalogen Solvent-Processed Organic Solar Cells Based on a Low-Cost Polymer Donor

Fabrication of high-efficiency organic solar cells (OSCs) using nonhalogen green solvents is highly desired for commercialization. However, the morphology control of a nonhalogen solvent-processed active layer remains challenging because of poor solubility of the commonly used photovoltaic materials in nonhalogen solvents. Herein, we propose a two-step heating strategy to optimize the morphology of a photovoltaic active layer based on a low-cost polymer donor X1 and a small-molecule acceptor (SMA) BTP-eC9 processed from a mixed nonhalogen solvent. First, heating the blend solution can robustly enhance the solubility of the SMA and thus processability of the blend, producing a uniform active layer. Second, further elevating the substrate temperature can shorten the film-formation time and tune the size of the polymer aggregates and SMA crystallites, to form bicontinuous networks in the active layer. As a result, this two-step heating strategy endows the film with improved charge generation, transport, and collection and thus a much higher device efficiency (ca. 4.6 times of that for the as-cast device) in comparison to those from nonoptimal solution and/or substrate temperatures. This work emphasizes the crucial role of regulating processing conditions in fabricating the nonhalogen solvent-processed high-efficiency OSCs.

CoSe2 nanoparticles anchored on dual 1D carbon nanotubes/N-doped carbon nanofibers as high-performance anodes for sodium-ion storage.

Transition metal chalcogenides (TMCs) have been widely explored and utilized in sodium-ion battery (SIB) anodes owing to their unique advantages, such as high theoretical specific capacity and low cost. However, their inherent defects, such as low electronic conductivity and severe volume expansion, seriously limit the further development of TMC-based anodes. Here, a novel composite material of CoSe2 nanoparticles (NPs) encapsulated in a dual one-dimensional (1D) carbon composite structure (CoSe2@CNTs/N-CNFs) was designed deliberately. Carbon nanotubes (CNTs) were grown in situ on the surface of carbon nanofibers (CNFs) with eco-friendly ethanol as the carbon source, while electrospun polyacrylonitrile (PAN) fibers were pyrolyzed to form nitrogen-doped nanofibers. It is noted that the wrapping with the composite carbon structure greatly improved the stability of CoSe2 NPs and solved its inherent defects as an anode material. When assembled into a half-cell, the CoSe2@CNTs/N-CNFs electrode exhibited outstanding sodium storage performance with a reversible specific capacity of 442 mA h g-1 after 100 cycles at 0.1 A g-1, as well as excellent rate performance, and the discharge specific capacity still reached 265 mA h g-1 even after 2000 cycles at a high current density of 5 A g-1. This study shows a new way to build a novel carbon substrate and TMC composite sodium storage material with low cost.

The effect of heating method on the gel structures and properties of surimi prepared from Bombay duck (Harpadon nehereus).

This study investigates the effects of heating method, setting time, and setting temperature on the gel properties, water holding capacity (WHC), molecular forces, protein composition, protein conformation, and water transition of Bombay duck (BD) surimi gel. The obtained results demonstrate that the best gel properties are obtained by two-step heating at 30°C for 120 min while the hardness was 10.418 N and the breaking force was 4.52 N. Gel softening occurs at setting temperatures greater than 40°C due to the effect of endogenous enzymes in destroying the protein structure and increasing the hydrophobic and disulfide interactions. Low-field nuclear magnetic resonance spectra confirm that high two-step setting temperatures induce gel softening and the destruction of the surimi gel structure, as evidenced by the increased water migration at these temperatures. Of all protein conformations in the gel, the β-sheet structure, decreases from 38.40% at 30°C to 11.75% at 60°C when the setting time is 60 min, is the most susceptible to gel softening. Overall, the data reported herein provide a scientific basis for the development of new BD surimi products on an industrial level.

Effect of two-step heating transient liquid phase bonding on microstructure and mechanical behaviour of IN-738LC gas turbine components

The long isothermal solidification and homogenization time is the major concern in repairing turbine parts by the conventional transient liquid phase method. In this study, microstructure and morphology of the proposed two-step heating transient liquid phase joints were compared to results of the conventional ones conducted at the same temperature. After the isothermal solidification, deleterious precipitates such as Ni3Si, Ni3B and CrB were removed. The application of the two-step technique increased the shear strength of the joints up to 28% (516–674 MPa) due to collision of two non-planar interfaces and formation of the longer bonding line. The shear fracture surfaces of all bonds with the complete isothermal solidification stage represent a dimple pattern that is characterized by ductile fracture. The stress-rupture life of the joint at 982 °C was about 85% of the superalloy service life at this temperature.

Interactions of heat-induced myosin with hsian-tsao polysaccharide to affect the fishy odor adsorption capacity

The interaction mechanism of hsian-tsao polysaccharide (HTP) with unique gel-promoting and biological activity for improving the gel properties of surimi was not clarified. This study investigated the effects of HTP on heat-induced structural changes and the adsorption capacity of myosin to fishy odor compounds (hexanal, heptanal, nonanal, and 1-octen-3-ol). HTP concentration and heating ways greatly affected the physicochemical properties of myosin. Adding hydrophilic HTP covering the myosin surface aided in unfolding the structure of myosin and further disturbed the myosin aggregation with surface hydrophobicity decreased and total sulfhydryl contents increased. The main physical forces arising from hydrogen bonding and electrostatic interactions contributed to forming HTP-myosin complexes under setting (40 °C, 30 min), whereas cross-links occurred by enhanced hydrophobic interactions forming insoluble HTP-myosin complexes under two-step heating (40 °C, 30 min; 90 °C, 20 min), indicative of decreased solubility and increased turbidity, as evidenced by zeta potential, FTIR, fluorescence and UV–vis spectra, and fluorescence microstructure. This resulted in the transformation of secondary structure of myosin from α-helix to β-sheet with the increase of HTP. Furthermore, HTP interacting with myosin reduced the fishy odor binding capacity of myosin thus promoting the release during processing, as demonstrated by HS-SPME-GC. The findings provided new insight into the mechanism of regulating the fishy odor binding ability of myosin by application of HTP.

A two-step heating strategy for low-temperature fabrication of high sinterability and fine MgAlON powder with MgAl2O4 as Mg source

Based on the reaction sequence during synthesis of MgAlON powder by solid-state reaction, a two-step heating strategy is proposed to low-temperature fabricate fine MgAlON powder of high sinterability by using MgAl2O4 as Mg source, respectively together with AlON and Al2O3+AlN. By introduction of an additional dwelling at 1550 °C to the first heating step, more α-Al2O3 dissolve into the solid solution at this temperature. By this way, overlarge particles of Al2O3 by agglomeration could be avoided in the next heating step to enable fast full reaction at a lower temperature. By dwelling 30 min at 1550 °C followed by 60 min at 1700 °C, single phase MgAlON powders were successfully prepared by solid-state reaction of all the two batches. The fine MgAlON powder synthesized by MAS+Al2O3+AlN batch exhibited high sinterability as the MgAlON ceramics pressureless sintered by this powder at 1880 °C without dwelling showed a transmittance up to 68.3%. The phase assemblage and morphology evolution of the mixture during solid-state reaction were monitored, which verified the effectiveness of the proposed two-step heating strategy. The low synthesis temperature of the two-step heating scheme benefits to prepare pure MgAlON powder with small particle size.

Towards creep property improvement of selective laser melted Ni-based superalloy IN738LC

• SLM IN738LC superalloy was treated with unconventional two-step heating schemes. • The 950 °C first step was found the most effective in redistributing the carbides. • Carbide redistribution significantly reduced grain boundary pinning and promoted grain growth. • Larger grain size led to 56% to 339% increments in creep life depending on creep strength. Nickel-based superalloy IN738LC produced by selective laser melting (SLM) exhibits inferior high-temperature creep properties than its cast counterparts due to relatively smaller grain size, particularly for the plane normal to the building direction. This work studied effects of post heating strategy on the microstructure and especially the grain size to improve the high temperature creep resistance. The as-built microstructure exhibited a fine grain size and large quantities of M C carbides that could effectively hinder grain growth. It was found that unconventional two-step heat treatments could lead to substantial grain growth, and the effect is particularly prominent at a specific temperature. The ease of grain growth was explained after classifying the microstructural evolution (boundary carbide transformation) during each heating step and related to the reduced grain boundary pinning force from M C carbides. Creep tests validated the effect of the new heat treatment scheme on the SLM-processed IN738LC at 850 °C. An extended creep fracture life (1.5 to 4 times improvement) and lower secondary creep rates were achieved with samples subjected to the newly optimized two-step heat treatment. The complete creep curves are also firstly presented for SLM-IN738LC, confirming the effectiveness of grain growth and highlighting the importance of dedicated heat treatment for SLM superalloys.

Rapid Strengthening of Interstitial Free Steel Using Amorphous FeC Thin Films and Induction Heating

A new process to rapidly obtain high-strength interstitial free (IF) steel was investigated. Thin sheets of IF steel were coated on one or both sides with an amorphous FeC film and subjected to a two-step induction heating cycle (1100 °C followed by an isothermal hold at 780 °C for 2 or 4 min) and a rapid quench in water. Tensile mechanical properties were measured, and a yield stress of 374 MPa and an ultimate tensile strength of 448 MPa were achieved after 2 min of induction heating. After 4 min of induction heating, the yield stress and the ultimate tensile strength drop at 206 and 320 MPa, respectively. During tensile testing, the specimens induction heated for 2 min show Lüdering, which is suppressed when the induction heating is extended to 4 min. Vickers microhardness measurements through thickness confirm that higher mechanical properties are obtained after 2 min of induction heating. Transmission electron microscopy reveals that strengthening results from dislocations, carbon in solid solution, and the precipitation of nanosized TiC particles. A fine microstructure with an average grain size of 15 μm is preserved after the induction heat treatment.

Molecular Mechanisms Involved in Thermally Induced Gel Formation of Japanese Codling Meat Paste during a Two-Step Heating Procedure

We analyzed changes in the rheological properties of Japanese codling (Physiculus japonicus) meat paste during the following two-step heating procedure: first preheating at 0–70 °C with 5 or 10 °C intervals and subsequent secondary main heating at 85 °C. Changes in the breaking strength and breaking strain rate showed roughly three phases associated with preheating temperatures of 0–25, 30–50, and 55–70 °C. The most prominent change was observed for preheated gels with preheating from 30 to 55 °C, where the myosin polymerization rate was high. The increase in the preheating temperature from 0 to 25 °C was accompanied by a gradual decrease in protein solubilization and a rapid increase in myosin polymerization for preheated gels, suggesting that gel formation occurred even at low preheating temperatures. Dynamic viscoelasticity measurements indicated that structural changes in myosin other than polymerization also participate in gel formation. Moreover, NH4Cl, an inhibitor of transglutaminase, reduced myosin polymerization in meat paste.