Heat Treatment Research Articles

Characterization and anti-tuberculosis effects of γδ T cells expanded and activated by Mycobacterium tuberculosis heat-resistant antigen.

Tuberculosis (TB) is a chronic infectious disease caused by Mycobacterium tuberculosis (Mtb) that poses a severe threat to human health. A variety of highly immunogenic tuberculosis proteins have been used as targets in vaccine development to mitigate the spread of TB. Although Th1-type immunity has long been considered a crucial part of resistance to Mtb, γδ T cells, the predominant source of IL-17, are not negligible in controlling the early stages of TB infection. In addition to classical phosphoantigens, Mycobacterium tuberculosis heat-resistant antigens (HAg), a complex containing 564 proteins obtained from live tuberculosis bacteria after heat treatment at 121 °C for 20 min, have been confirmed to be highly effective γδ T cell stimulators as well. Several studies have demonstrated that HAg-activated γδ T cells can participate in TB immunity by secreting multiple cytokines against Mtb or by interacting with other innate immune cells. In this review, we present a possible mechanism of HAg stimulation of γδ T cells and the role of HAg-activated γδ T cells in anti-TB immunity. We also highlight the limitations of studies on HAg activation of γδ T cells and suggest further research directions on the relationship between HAg and γδ T cells.

Triple Corrosion Protection: Dual-Layer Coating with Simultaneous Superhydrophobicity, Intelligent Self-Healing, and Shape Memory.

In this paper, a self-healing superhydrophobic smart two-layer coating, ZOA/SMP-S, was developed. ZIF-8 was surface hydrophobically modified by octadecylphosphoric acid (OPA) to obtain Z-OPA and then encapsulated with a corrosion inhibitor, AMT ( 2-Amino-5-mercapto-1,3,4-thiadiazole), to obtain the superhydrophobic nanocontainers, ZOA. ZOA was embedded into the SMP (shape memory coating) to obtain the smart coating, and Z-OPA was sprayed to obtain the second superhydrophobic coating. SEM showed that the scratch coatings were rapidly reduced by scratches after a simple heat treatment. The prepared composite coatings showed excellent performance in corrosion inhibitor release, immersion, superhydrophobicity, and self-healing experiments. The contact angle of the superhydrophobic coating reached 158.2°, and the sliding angle was 2.8°. The low-frequency impedance value |Z|f=0.01Hz of ZOA/SMP-S is as high as 1.58 × 1010 Ω·cm2 after 40 days of immersion test, which indicates that the triple protection greatly enhances the corrosion resistance of the coating.

Dynamic photoelastic analysis of stress distribution in simulated canals using different heat-treated flat-side rotary instruments.

This study aimed to compare the stress produced by three heat-treated flat-side prototype rotary instruments and a non-flat side instrument on the internal walls of simulated canals with three different curvature degrees using the photoelastic technique. Thirty-six resin blocks with simulated canals, comprising three curvature types (45°, 60°, and double curvature), were used in the study, with 12 blocks allocated to each curvature type. These blocks were further divided into four experimental groups (n = 9 per group) based on the heat treatment of the instruments: gold, silver, blue, and a control group with non-flat-side gold instruments. The blocks were analyzed using a circular polariscope setup, with real-time birefringence patterns captured by a digital camera. Stress on canal walls was evaluated using a semi-quantitative scale. Supplementary tests (stereomicroscope, SEM, energy-dispersive X-ray spectroscopy, and DSC) were performed to interpret the results further. Data were analyzed using the Kruskal-Wallis test (α = 5%). Inter- and intra-observer agreements were 0.91 and 1, respectively. All instruments exhibited high stress patterns on canal walls. The highest stress was observed in the 45° and 60° blocks (middle third) and the double curvature blocks (apical third). The flat-side gold instrument recorded the highest stress in the coronal third, and the flat-side blue in the apical third (p < 0.05). All instruments displayed some degree of distortion after use. Instrument type and canal curvature significantly influenced stress distribution across root canal thirds. All flat-side instruments exhibited high stress patterns, warranting caution in curved canals due to potential distortion and performance impact. This study recommended caution when using newly designed flat-side instruments in curved canals due to potential stress on canal walls and greater distortion, which may affect performance and durability.

Effect of a Novel Heat Treatment on the Corrosion Resistance of Duplex Stainless Steel S32101

Effect of a Novel Heat Treatment on the Corrosion Resistance of Duplex Stainless Steel S32101

Influence of welding heat input and post-weld heat treatment on mechanical and microstructural properties of modified 9Cr-1Mo (P91) steel in submerged arc welding

Influence of welding heat input and post-weld heat treatment on mechanical and microstructural properties of modified 9Cr-1Mo (P91) steel in submerged arc welding

Analysis of Heat Treatment of AlSi7Cu0.5Mg Alloy

Analysis of Heat Treatment of AlSi7Cu0.5Mg Alloy

Investigation and prediction of fatigue performance of SLM 316 L stainless steel based on small build orientation variations and heat treatment effects

Additive manufacturing (3D printing) has facilitated the creation of complex structures, including lattices with diverse build angles. Since lattices often face quasi-static and cyclic loads, understanding material properties across a wide range of printing angles, post-processing conditions, and loading scenarios is crucial. This study explores the effects of building orientations beyond conventional 0, 45, and 90 degrees on the mechanical properties of 316 L steel, produced by laser powder bed fusion. Quasi-static and cyclic tensile tests were performed to evaluate mechanical behavior in as-built and heat-treated conditions, followed by predictive model development. The ultimate strength showed a modest variation of 7% in the as-built condition, while the heat-treated state exhibited a greater variation of 13%. Fatigue tests indicated minor differences between conditions in the low-cycle region but larger gaps in the high-cycle region, where heat-treated samples generally showed superior performance. Inclination angle had a greater effect on fatigue life in the as-built state, with horizontal part orientations outperforming vertical ones. The predictive model demonstrated robust reliability, with nearly 90% of data within an accepted scatter factor of less than three. Requiring minimal experimental data (two fatigue curves per condition), the model is valuable for forecasting fatigue behavior in complex lattice structures.

Effects of Heat Treatment on Plasma-Sprayed Indian Clam Seashell-Derived Hydroxyapatite (HA) Coating Applied on Ti-Alloy

Effects of Heat Treatment on Plasma-Sprayed Indian Clam Seashell-Derived Hydroxyapatite (HA) Coating Applied on Ti-Alloy

Microstructure and mechanical properties of a novel Al-Cu-Si-Ce alloy with high strength for additive manufacturing

ABSTRACT The mechanical properties and microstructure of a novel Al-Cu-Si-Ce-based alloy produced by selective laser melting (SLM) were studied. The influence of the printing modes on the porosity was investigated. The minimum porosity (0.2 ± 0.05%) was obtained at an overhatch of 130 µm, velocity of 300 mm/s and power of 200 W. The microstructure of the alloy after SLM contains fine particles of solidification origin (Si), Al2Cu and Al8Cu4Ce phases. The solution treatment, quenching and aging heat treatment provide a high ultimate tensile strength of 490 MPa, elongation up to 4% and yield strength at 250°C of 185 MPa. Good combinations of properties make the investigated alloy a prospective material for aircraft applications.

Effects of Supplementation of Different Proteins on the Rheological Properties of Liquid Whole Eggs

This study aimed to evaluate the impact of increasing total protein content on the rheological properties of liquid whole eggs. The study fills the gap between fundamental science and industrial application by exploring the potential for developing high-protein, functional egg products for health-conscious consumers and the food industry. Liquid whole egg samples were enriched with different percentages of egg white and whey proteins. Proteins were added either before or after heat treatment, followed by homogenization, to analyze the effects on rheological behavior. Results indicated that whey protein samples exhibit near-Newtonian behavior due to their high solubility and minimal protein interactions, while egg white protein samples, especially at higher concentrations, induce shear thinning behavior and increased viscosity due to their water-binding capacity and partial heat-induced denaturation. Flow behavior index (n) decreased by 62.7 ± 5.7% and 25.2 ± 1.8% for heat treated with 10% added egg white and whey protein samples, respectively; meanwhile, it decreased by 2.64 ± 0.06% for 10% of added egg white protein and increased by 12.0 ± 1.0% for 10% of whey protein when heat treatment was induced prior to protein additions. The findings from this study offer valuable insights for developing functional food enriched with whey and egg white proteins.

Identification and Biological Characterization of a Novel NRF2 Activator Molecule Released From the Membranes of Heat-Treated Bifidobacterium breve NCC 2950.

Postbiotics are defined as a "preparation of inanimate microorganisms and/or their components that confers a health benefit on the host". They represent an attractive alternative to probiotics as they could be used in a broader range of applications, where probiotic stability is limiting. To date knowledge on the mechanism of action of inanimate microorganisms is relatively scarce. In this study, we investigated the impact of heat treatment on NRF2 activation by several candidate probiotic strains from the Nestlé Culture Collection (NCC), including species encompassed in the Bifidobacterium genus and the Lactobacillaceae family. We identified an NRF2-activating bioactive molecule, 4-oxo-2-pentenoic acid (OPA), specifically released during heat treatment of Bifidobacterium breve NCC 2950. We explored cellular pathways that can be modulated by OPA, such as antiinflammatory signals and organismal defense against oxidative stress in zebrafish in vivo. We identified a new B. breve NCC 2950-derived postbiotic that, based on the mode of action, may have important applications for nutritional strategies to benefit human health.

Introduction of 3D-printed porous structures with interconnected porosities via rotation of each layer around a normal axis: Investigating the effects of annealing and printing parameters on the compressive strength and modulus of the structures

Abstract This study introduces 3D-printed porous structures made of polylactic acid (PLA) with interconnected porosities for tissue engineering as an alternative to bone scaffolds. Then the effects of process parameters and annealing heat treatments on the compressive strength and modulus of the porous samples have been investigated. The examined parameters include extrusion width, layer height, infill pattern, and infill percentage. To create porous structures with interconnected porosities, the infill pattern is rotated by eighteen degrees in each layer, forming new porous structures that can be utilized as bone scaffolds in tissue engineering. After evaluating the compressive mechanical properties of the samples and examining the effects of printing parameters on them, similar samples were subjected to heat treatment, and their compressive mechanical properties were also investigated. The results indicate that the maximum compressive strength and modulus occur in the sample with an extrusion width of 0.6 mm, a layer height of 0.25 mm, a wiggle infill pattern, and a maximum infill percentage. The un-heat-treated sample's compressive strength and modulus values are 84.51 MPa and 2.28 GPa, respectively. In contrast, these values are 105.44 MPa and 2.29 GPa for the heat-treated sample.

Effect of Collagen Peptide and Polysaccharide Combination on Astringency Elimination, Appearance, and Syneresis in Persimmon Paste

Astringency in persimmon fruit is often eliminated by treatment with gaseous carbon dioxide, dry ice, or alcohol. However, these methods are time-consuming and labor-intensive, and astringency may recur after heat treatment. In this study, a method for easily reducing astringency was investigated by taking advantage of the benefits of combining proteins and polysaccharides. In the first experiment, the protein materials with strong astringency-reducing effects were screened from among 15 protein-rich foods using astringent persimmon juice (APJ), and collagen peptides were found to be highly effective. However, syneresis was observed when 1% collagen peptide powder was added to the astringent persimmon paste (AP). Therefore, in the second experiment, 0.5% collagen peptides (protein) were applied to reduce heating-induced astringency and reversion and 0.5% polysaccharides (guar, and xanthan gums) to maintain color and suppress syneresis. The results demonstrate that the combination of collagen peptide and polysaccharides is optimal for removing astringency in persimmon, inhibiting its recurrence by heating, and maintaining product quality. The results of this study may reduce the labor required for the astringency removal process, broaden the uses of AP, and facilitate the effective utilization of discarded astringent persimmons that do not meet the standards.

ИССЛЕДОВАНИЕ ПОКАЗАТЕЛЕЙ БЕЗОПАСНОСТИ ПРОДУКЦИИ ДИЕТИЧЕСКОЙ НАПРАВЛЕННОСТИ (НА ПРИМЕРЕ БЕЗЛАКТОЗНЫХ ИЗДЕЛИЙ ДЛЯ ДЕТСКОГО ПИТАНИЯ)

The purpose of the study is to analyze the safety indicators of products for the organization of baby food for dietary purposes, to analyze the shelf life and safety indicators of the ready-made chilled dish “Lactose-free cottage cheese casserole with pumpkin”. Objectives: to conduct a study of microbiological, organoleptic indicators of a lactose-free curd product, to compare with the indicators of a dish prepared according to a collection of technical standards. To confirm the shelf life of safety indicators, studies were carried out with a frequency of 24 hours over a period of 120 hours (5 objects). The paper provides a description and results of a study of the safety indicators of a lactose-free dish for feeding children with lactose intolerance in organized groups, developed by the design method, based on an existing dish from a collection of technical standards. Organoleptic and microbiological indicators were studied, and comparisons were made with indicators according to regulatory documentation. The results of the study show that the actual shelf life of the developed dish should be reduced in comparison with the periods stated in the regulatory documentation and is 3 days (72 hours) subject to intensive cooling 2 hours after the end of heat treatment and storage at a temperature of 4 ± 2 °C in the refrigerator camera.

The effect of heat treatment on crystal structure and thermodynamic properties of Cu–Al–Ni shape memory alloy

The effect of heat treatment on crystal structure and thermodynamic properties of Cu–Al–Ni shape memory alloy

Hardness enhancement of commercially pure aluminium by a typical cyclic heat treatment process involving repeated ice‐brine quenching

AbstractA typical cyclic heat treatment process has been adopted up to four cycles on initially annealed commercially pure aluminium, primarily containing iron impurity, that involves short‐duration (5 minutes) holding at 600 °C followed by ice‐brine quenching in each cycle. As a consequence, a significant grain refinement effect and a gradual accumulation of lattice strain during the progress of cyclic heat treatment are observed in relation to an evolution of the regions of extremely low misorientation angle in the aluminium matrix. Apart from quench‐in strain, the presence of grain boundary iron aluminide phase, possessing a different coefficient of thermal expansion than that of aluminium matrix, appears to be an additional reason for gradual lattice strain development. In addition, a preferred growth of (202) plane along [101] direction towards the final stage of cyclic heat treatment (four cycles) is also revealed. As a result of gradual lattice strain accumulation and grain refinement effects, the hardness of commercially pure aluminium is found to be considerably enhanced (98 HV 10) after 4 cycles of heat treatment as compared to an initial hardness (36 HV 10) in annealed condition.

Coalescence of carbon nanotubes while preserving the chiral angles.

Atomically precise coalescence of graphitic nanocarbon molecules is one of the most challenging reactions in sp2 carbon chemistry. Here, we demonstrate that two carbon nanotubes with the same chiral indices (n, m) are efficiently coalesced into a single (2n, 2 m) nanotube with preserved chiral angles via heat treatment at less than 1000 °C. The (2n, 2 m) nanotubes constitute up to ≈ 20%-40% of the final sample in the most efficient case. Additional optical absorption peaks of the (2n, 2 m) nanotubes emerge, indicating that the reaction occurs over the entire sample. The reaction efficiency strongly depends on the chiral angle, implying that C-C bond cleavage and recombination occurs sequentially. Furthermore, the reaction occurs efficiently even at 600 °C in an atmosphere containing trace amounts of oxygen. These findings offer routes for the structure-selective synthesis of large-diameter nanotubes and modification of the properties of nanotube assemblies via postprocessing.

Protolytic Reactions at Electrified TiO2 P25 Interface: Quantitative and Thermodynamic Characterization

Protolytic reactions on the surface of a titania photocatalyst (TiO2 P25 containing chlorine impurities) were studied using potentiometric and calorimetric acid-base titration. The impurity was removed by either washing or heat treatment. The efficiency of purification was tested by chlorine (TOX) analysis and acid-base titration. Common intersection points of −0.023 and −0.021 mmol/g were obtained for the original and 400 °C heat-treated samples, which are in good agreement with the measured TOX value of 28 mmol/kg. The point of zero charge of the purified sample was determined to be 6.50. Titration data were fitted to simulate protolytic reactions during isothermal calorimetric titrations of purified titania. The evolved heat was measured, and data points were corrected with the heat of mixing and neutralization. The quantity of charged surface species formed in each step of titration was calculated using the parameters from the constant capacitance model fit. The partial molar enthalpy values of the exothermic and endothermic processes of surface protonation (ΔHpr, −17.47 to −16.10 kJ/mol) and deprotonation (ΔHdepr, 32.53 to 27.08 kJ/mol) depend slightly on the ionic strength of suspensions. The average standard enthalpy of one proton transfer reaction is −23.54 ± 1.75 kJ/mol, which is consistent with the literature.

A Comparison Between the Residual Stresses of Ti6Al4V and Ti-6Al-2Sn-4Zr-6Mo Processed by Laser Powder Bed Fusion

Metal additive manufacturing processes induce residual stress in as-built components. These residual stresses are detrimental to part quality as they can induce defects such as warping and delamination. In some cases, when complex components are built, residual stress can even cause a build job to fail due to the recoater crashing into the distorted part. In this paper, the residual stress values of Ti6Al4V and Ti-6Al-2Sn-4Zr-6Mo alloys were evaluated by the cantilever approach and by the X-ray diffraction sin2(Ψ) method. The results showed that, as expected, Ti6Al4V as-built cantilevers displayed high distortion and von Mises equivalent stress values up to 494 MPa. On the contrary, as-built Ti-6Al-2Sn-4Zr-6Mo cantilevers were characterized by almost null warping and a residual stress value in the as-built state of 191 MPa. This different behavior is mainly due to the different properties of the hexagonal α’ martensite in Ti6Al4V and the soft orthorhombic α’’ martensite in Ti6246. The post-processing heat treatment significantly reduced the residual stress in Ti6Al4V, lowering it to 44 MPa, while, in the case of Ti-6Al-2Sn-4Zr-6Mo, the post-processing heat treatment did not affect the residual stress conditions. These findings suggest that Ti-6Al-2Sn-4Zr-6Mo could be a suitable candidate for the additive manufacturing production of extremely complex parts, as it could reduce the risks associated with recoater crashes and job failures.

Static and Fatigue Properties of Rhenium-Alloyed Inconel 718 Produced by Powder Bed Fusion Additive Manufacturing

Inconel 718 (In718) is the most widely used nickel-based alloy in additive manufacturing due to its favorable processability. However, In718’s high-temperature performance is not suited for the most demanding applications in the aerospace industry. Therefore, in this study, Inconel 718 powder was coated with 3% wt. rhenium (In718-Re) using AM’s in situ alloying capabilities to improve high-temperature properties. The proposed alloy’s mechanical performance was evaluated, focusing on the effects of post-process heat treatment and hot isostatic pressing following the laser-based powder bed fusion of metals (PBF-LB/M) processing. Static tensile tests conducted at room temperature and elevated temperatures (650 °C and 760 °C) demonstrated that the alloy has comparable strength to pure In718 according to ASTM F3055-14a—an ultimate tensile strength of 1247 MPa, yield strength of 909 MPa, and almost 2× higher elongation of 23.8%. Fatigue tests at room temperature indicated a fatigue limit below 400 MPa for 107 cycles. Fractographic analysis revealed that fatigue performance was primarily impacted by a lack of fusion defects inherent to the PBF-LB/M process, highlighting the need for optimized powder preparation and processing parameters to minimize defect formation. While rhenium addition shows limited benefits in Inconel 718, this study underscores the potential of in situ alloying through powder surface modification as a flexible method for incorporating high-melting-point elements into nickel-based alloys for tailored alloy design in additive manufacturing.