Effect Of Aging Time Research Articles

Evolution of shape memory effect with aging time during aging after pre-strain in Fe–Mn–Si–Cr–Ni–C shape memory alloys

The shape memory effect of Fe–Mn–Si–Cr–Ni–C shape memory alloys could be significantly improved by aging after pre-strain, because a high density of directional Cr23C6 particles is precipitated. However, the variation of shape memory effect under a large deformation-strain with aging time is not evident in the Fe–Mn–Si–Cr–Ni–C alloys subjected to aging after pre-strain. In order to clarify the above issue, the effect of aging time on the microstructures and the recovery-strain under a large deformation-strain of 7.5% for the Fe–Mn–Si–Cr–Ni–C alloy subjected to aging for 10–300 min after 10% pre-strain at room temperature was systematically investigated by XRD, SEM, EBSD, and EPMA. When the aging time was 30 min, the maximum recovery-strain of 5.4% was achieved. The recovery-strain increased from 4.9% to 5.4% when the aging time was extended from 10 min to 30 min. It is attributed to that the fraction of twin boundaries, inhibiting stress-induced ε martensitic transformation, decreased from 19.1% to 14.2%, as the precondition that the density of stacking faults, promoting stress-induced ε martensitic transformation, remained nearly constant. When the aging time was extended from 30 min to 180 min, the recovery-strain decreased from 5.4% to 4.6% due to both the decrement of stacking faults and the increment of twin boundaries.

First insights about the underlying mechanisms of Martina Franca donkey meat tenderization during aging: A proteomic approach

This study aimed to evaluate the effect of different aging times (1, 6 and 14 days) on the tenderization rate and protein changes in ten Martina Franca donkey striploins using a proteomic approach. During aging, a progressive decrease in share force, hardness, gumminess, and chewiness together with an increase in myofibril fragmentation index were observed. Proteolysis monitored by immunoblotting revealed a progressive degradation of desmin and fast troponin-T over time and an increase of their degradation products up to 14 days aging. Proteomics revealed by means of two-dimensional electrophoresis 37 protein spots corresponding to 15 proteins to change significantly by increasing aging time. These proteins belong to three pathways, these being “muscle contraction, structure, and associated proteins” (9 proteins); ii) “energy metabolism” (5 proteins); and iii) “chaperone” (1 protein). This study is the first to highlight the possible role of interconnected pathways in driving the final quality of donkey meat and predicting its texture.

Interactive effects of NOx synergistic and hydrothermal aging on soot catalytic combustion in Ce-based catalysts

The Thermal gravimetric analysis (TGA) with In-situ Fourier transform infrared Spectrometer (In-FTIR) of fresh/hydrothermal aging Ce-based catalysts was carried out for the soot oxidation at different transition metal Mn, alkali metals K, precious metals Ag and rare earth metal Zr doping which used to extend the hydrothermal aging resistance of CeO2 catalysts. The comprehensive combustion index S, combustion stability index Rw and peak temperature Tp from TG-DTG curves were extracted to evaluate the soot catalytic combustion performance, and the NO2/NO ratio during the combustion process was also measured to analyze the NOx synergistic oxidation performance. The effect of metal oxide doping type, doping ratio and hydrothermal aging time on S, Rw, Tp and NO2/NO ratio was evaluated to reveal the change in soot catalytic combustion performance. The result shows that, compared with PU, the NOx synergistic oxidation performance of various metal oxides modified Ce-based catalysts ranked as K > Ag > Mn > Zr. With the metal oxide doping ratio increased, the soot catalytic combustion performance of K and Zr metal oxides modified Ce-based catalysts decreased, Mn and Ag metal oxides modified catalyst increased. After hydrothermal aging treatment, the NOx synergistic oxidation performance of various metal oxides modified Ce-based catalysts ranked as K > Ag > Mn > Zr. This work is helpful to reveal the basic mechanism of hydrothermal aging metal oxide modified Ce-based catalyst and NOx during soot catalytic combustion process.

Competition between continuous and discontinuous precipitation in L12-strengthened high-entropy alloys

Understanding of the competition between continuous precipitation (CP) and discontinuous precipitation (DP) is crucial for tailoring the microstructure and mechanical properties of precipitation-strengthened high-entropy alloys (HEAs). In this study, the effects of aging temperature, aging time, and grain size on the CP and DP behaviors of L12-strengthened HEAs were systematically investigated. Our results reveal that low temperatures favor the DP reaction while high temperatures facilitate the CP reaction, which is related to the nucleation site and diffusion path of the two precipitation modes. At intermediate temperatures, both the CP and DP occur simultaneously and compete with each other, and the solute concentration difference across the boundaries between the two precipitation regions serves as the driving force for the sweeping of the CP regions by the DP reaction. In addition, grain size refinement can promote the DP reaction by providing more nucleation sites and more fast diffusion paths, leading to the formation of the DP-dominant microstructure. This study not only sheds light on the fundamental understanding of the CP and DP mechanisms but also provides useful guidelines for the microstructure design of advanced L12-strengthened HEAs.

Effect of Aging Time on the Corrosion Resistance of the As-cast Al-Cu-Mg-Mn Alloy

Effect of Aging Time on the Corrosion Resistance of the As-cast Al-Cu-Mg-Mn Alloy

The Effects of Processing Time on the Total Phenolic, Flavonoid Content, and Antioxidant Activity of Multi Bulb and Single Bulb Black Garlic

Black garlic is produced by processing multi-bulb garlic (Allium sativum) or single-bulb garlic in high temperature and high humidity for several days. Black garlic has many health benefits, such as an antioxidant activity resulting from its compound, including groups of flavonoid and phenolic compounds. This study aimed to analyze the effect of aging time on multi-bulb and single-bulb black garlic on the content of total phenolic, flavonoid, and antioxidant activity. Black garlic was processed at a 60-70°C heating temperature and 70-80% relative humidity for 25 days. Determination of total phenol and flavonoid contents was conducted using spectrophotometric methods with gallic acid as a standard of total phenolic and quercetin as a standard of flavonoid, while the antioxidant activity was determined by DPPH radical reduction. The results showed that total phenolic contents (% w/w GAE), flavonoids contents (% w/w QE), and EC50 values at 0 until day 25 increased on a particular day in multi-bulb and single-bulb black garlic. The optimal total phenolic content of both black garlic was obtained by heating for 20 days, flavonoid content of multi-bulb garlic for 10 days, and single-bulb black garlic for 15 days. Highest antioxidant activity was obtained on days 20 and 25 for single-bulb black garlic and multi-bulb black garlic, respectively. The aging time of black garlic affects total phenolic, flavonoid content, and antioxidant activity. In general, longer processing time caused an increase in the total phenolic content, flavonoid content, and antioxidant activity of both black garlics. Multi-bulb black garlic showed higher phenolic or flavonoid content and antioxidant activity than single-bulb black garlic.

THE EFFECT OF HEAT TREATMENT AND SURFACE ANODIZATION ON FRICTION AND WEAR COEFFICIENT OF ALUMINIUM 2024 USING PIN ON DISK METHOD

The use of aluminum alloys as a material for engineering components that rub against each other is increasing, so it is important to know the friction characteristics of these aluminum alloys. In this study, Aluminum 2024 was given heat treatment with variation in aging time and anodization. Then, the wear and friction coefficient tests were carried out using a pin tool on the disc. The effect of aging time and surface anodization on wear tests are carried out to determine the amount of wear and the coefficient of friction test is carried out to determine the coefficient of friction of the material when it rubs against a pin made of AISI 52100 Steel. The coefficient of friction test is carried out by adding lubrication as a parameter. The test results showed that the aluminum material given heat treatment had better resistance than that which was not heat treated. This is because the heat treatment creates precipitates that can increase the aluminum's hardness and wear resistance. Whereas for anodized specimens, the alumina layer can act as an abrasive grain when given a high enough friction and load continuously, so the wear testing mode changes from dry sliding wear to three body abrasive wear and decreased wear resistance. From the friction coefficient test results, the aging time affects the hardness of the aluminum alloy, which leads to the value of the coefficient of friction. The harder the sample surface, the smaller the coefficient of friction obtained. Furthermore, applying lubricant to the sample will also decrease the value of the friction coefficient of the sample. Lubricating oil will provide a more significant reduction in friction coefficient than air. Finally, the anodizing surface on the sample will act as a lubricant reservoir when it occurs.

Synthesis and application of nanometer hydroxyapatite in biomedicine

Abstract Nano-hydroxyapatite (nano-HA) has been widely studied as a promising biomaterial because of its potential mechanical and biological properties. In this article, different synthesis methods for nano-HA were summarized. Key factors for the synthesis of nano-HA, including reactant concentration, effects of temperature, PH, additives, aging time, and sintering, were separately investigated. The biological performances of the nano-HA depend strongly on its structures, morphology, and crystallite sizes. Nano-HA with different morphologies may cause different biological effects, such as protein adsorption, cell viability and proliferation, angiogenesis, and vascularization. Recent research progress with respect to the biological functions of the nano-HA in some specific biological applications are summarized and the future development of nano-sized hydroxyapatite is prospected.

Optimization of formation of phase pure hydroxyapatite and fabrication of electrochemically stable HAP coatings on 316L SS for orthopedic applications

AbstractImpact of sintering temperature and aging time was investigated on purity and phase of hydroxyapatite powders synthesized through sol–gel process. Phase, composition, and morphology of the prepared hydroxyapatite powders were characterized using X‐ray diffraction (XRD), Fourier transform infrared (FT‐IR), and scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS). Plausible mechanism respective to the formation of HAP from the precursors Ca(NO3)2·4H2O and triethyl phosphite (TEP) by sol–gel process was determined from 31P NMR analysis. Further, the development of hydroxyapatite coatings on 316L SS metallic surfaces was done by varying the spin coating parameters such as spin speed, spin time, and sintering atmosphere, and their corrosion resistance behavior in SBF solution was evaluated by electrochemical impedance spectroscopy (EIS) and TAFEL polarization analysis. From the results, we inferred that the HAP coatings deposited on 316L SS surfaces at 3000 rpm/min under nitrogen atmosphere sintering have shown improved corrosion resistivity. The effect of aging time, sintering atmosphere, and spin speed was evaluated in terms of corrosion resistance behavior.

Effect of long-term aging treatment on the tensile strength and ductility of GH 605 superalloy

Aging treatment is an effective way to optimize the mechanical properties of Co-based superalloys. In this study, commercial GH 605 superalloy was subjected to aging treatment at 650 ​°C in a wide time range up to 1000 ​h. The effects of aging time on the tensile characteristics, microstructure evolution and mechanical properties were systematically investigated at room temperature (RT) and 900 ​°C. The results showed that the volume fractions of M6C and M23C6 carbide increased with the aging time. After long-term aging treatment, the yield strength (YS) at RT was enhanced from 490.3 ​MPa to 805.9 ​MPa, while the alloy still had high tensile ductility (above 20%). Microscopic observations by transmission electron microscopy (TEM) indicated that the strengthening mechanism was related to carbide precipitation inside the grains and the change in the dislocation slipping mode. Moreover, long-term aging treatment can increase the elongation from 24.1% to 47.3% at 900 ​°C accompanied by a slight increase of YS from 299.3 ​MPa to 313.9 ​MPa. Based on detailed microstructure analysis the strengthening mechanism can be attributed to the refined grains as well as carbide precipitation inside the grains and around the grain boundaries.

Effect of Aging Time of Squabs on Microbiological Characteristics and Quality Attributes of Their Meat

ABSTRACT The quality of squab meat subjected to “faisandage” treatment during the usual aging time was evaluated through the evolution of microbial and physicochemical properties. Twenty-seven whole squabs (young pigeon) were slaughtered, hung, and stored at 0–4°C in a cooling chamber. After 0, 7, and 14 aging days, the carcasses of squabs were obtained to carry out different analyses (total viable bacteria, Enterobacteriaceae and Escherichia coli (E. coli) counts, detection of Salmonella spp., Campylobacter spp., Listeria monocytogenes, and E. coli O157:H7, and pH, thaw and cooking losses, and shear force). In general, the squab meat subjected to “faisandage” treatment over 7 or 14 days at 0–4°C presented microbiological quality and physicochemical properties similar to that squab meat from day 0. The values of thaw losses, shear force, and pH obtained in this study allowed to distinguish among squab meat aging during 7 or 14 days and meat squab without aging.

Effect of natural aging time on tensile and fatigue anisotropy of extruded 7075 Al alloy

In this study, 7075 Al alloy was prepared by solution treatment + natural aging. The anisotropic behavior of 7075 Al alloy in extrusion direction (ED), 45° direction (45°) and radial direction (RD) was studied by quasi-static tensile test and strain controlled low cycle fatigue (LCF) test. The specimens of ED, 45° and RD were 0°, 45° and 90° to the extrusion direction of the bar, respectively. The mechanical properties of the specimens in three directions showed strong anisotropy. The yield strength (YS) and ultimate tensile strength (UTS) of ED specimens were better than 45° and RD specimens, but 45° specimens had better plasticity. With the extension of aging time, the YS and UTS increase significantly. In the quasi-static tensile process, the specimens would have dynamic strain aging (DSA), and obvious serrated flow behavior could be observed on the curve. For the fatigue performance of specimens in three directions, when the strain amplitude was low, the fatigue life of ED and 45° specimens was high. When the strain amplitude was high, the fatigue life of RD specimens was high. The experimental results showed that after cyclic loading, the second phase size of solution treatment + cyclic loading specimens was larger than T6 (480 °C × 3 h + 130 °C × 24 h). Therefore, the fatigue fracture mode was multi-source fracture at low strain amplitude.

Volatile composition of Spanish red wines: effect of origin and aging time

Volatile composition of Spanish red wines: effect of origin and aging time

Influence of Aging Time on Vertical Static Stiffness of Air Spring

To study the aging mechanism of air springs, the effect of aging time on the vertical static stiffness of an air spring was systematically analyzed by means of an accelerated aging test and finite element simulation. Accelerated aging tests were carried out on the entire air spring, rubber material, and cord material, and the vertical static stiffness and elastic moduli of the rubber and cord materials of the entire air spring were obtained with aging time. The finite element simulation model of the air spring was established. Based on the experimental data, the influences of the elastic moduli of the rubber and cord materials, aged for different times, and the cord angle on the vertical static stiffness of an air spring were simulated and analyzed, and the law of the influence of aging on the vertical static stiffness characteristics of air springs was revealed.

Effect of natural aging time on anisotropic plasticity and fracture limit of Al7075 alloy

Numerical approaches for fracture modeling have been proposed for various metallic materials, including high-strength steels and aluminum alloys. However, the quantitative relationship between the Portevin–Le Chatelier (PLC) effect and the fracture initiation has not been yet fully explored, considering the influence of the natural aging time (NA) on the material deformation behavior. To address this gap, this study investigated the PLC effect on the anisotropic plasticity and fracture limit of Al7075 alloy according to the natural aging time. Aging behavior and PLC effects are experimentally evaluated through uniaxial tensile and fracture tests using the 3D digital image correlation method. The natural aging-dependent PLC effect is tracked in the visualization of the strain rate map and thickness strain distributions with plastic deformation. Variations in the anisotropic plasticity are captured using Barlat’s YLD2000‐2d anisotropic yield function at different natural aging times, and fracture envelopes that cover general 3D stress states are identified based on the Lou–Huh ductile fracture criterion. A natural aging-dependent fracture modeling approach is proposed to predict the influence of natural aging on the fracture limit transition. Finally, the strain- and stress-based fracture forming limit diagrams, including their corresponding magnitude of the stress vector, are represented. The results reveal that no general trend for the natural aging-dependent fracture limit based on the strain metric is observed, whereas the fracture limit based on the stress metric tends to increase with natural aging in various loading conditions.

A physics-informed multi-agents model to predict thermo-oxidative/hydrolytic aging of elastomers

This paper introduces a novel physics-informed multi-agents constitutive model to propose prediction in quasi-static constitutive behavior of cross-linked elastomer and the loss of mechanical performance during environmental aging. The presented model is used to simulate the effect of single-mechanism chemical aging (i.e. thermal-inducedor hydrolytic aging) on the behavior of the material in this hybrid framework. Those environmental single-mechanism damages change the polymer matrix over time due to massive chain scission, chain formations, and changing the arrangement of molecules in the polymer matrix. We propose a data-driven super-constrained machine-learned engine to represent damage in the polymer matrix and capture the changes in material behavior, including its inelastic features such as Mullins effect and permanent set in the course of aging. We have simplified the 3D stress–strain tensor mapping problem into a small number of super-constrained 1D mapping problems by means of a sequential order reduction. An assembly of multiple replicated conditional neural-network learning-agents (L-agents) is trained to systematically simplify the high-dimensional mapping problem into multiple 1D problems, each represented by a different type of agent. Our hybrid framework is designed to capture the effect of deformation history, aging time, and aging temperature. The model is validated with respect to a comprehensive set of experiments specifically designed to benchmark model capabilities and also against available data in the literature. Thermodynamic consistency and frame independency have been verified. Besides acceptable predictive abilities, a significant reduction of computational cost to predict behavior at multiple states of deformation is the most significant feature of this model.

Experimental study on the durability of polymer‐impregnated basalt textile applied as concrete reinforcement

AbstractThis paper presents an experimental study on the durability of polymer‐impregnated basalt textile considering the effects of impregnation material, corrosion temperature, and corrosion solution. The variations in tensile strength, elastic modulus, surface condition, and failure mode were examined. Furthermore, a prediction model for the tensile strength degradation of basalt textiles was proposed. The experimental results showed that the tensile strength degradation of the textile was significantly influenced by the impregnation materials. The epoxy resin/acrylic emulsion‐impregnated textiles had superior durability to the styrene‐butadiene latex/vinyl resin‐impregnated textiles. As the temperature increased, the tensile strength decreased, whereas the variation in the elastic modulus was insignificant. In addition, the tensile strength of the weft textile degraded slightly faster than that of the warp textile owing to the larger contact area with the corrosion solution for the former. The saline–alkaline solution was more aggressive than the alkaline solution for the impregnated textiles owing to the corrosion caused by the combination of alkaline hydroxide ions and salt chloride ions in the former. The proposed model to predict the strength degradation considering both the aging time and temperature effect is in good agreement with the experimental results, which can be used to predict the long‐term strength of basalt textiles used as concrete reinforcement in real engineering applications.

Beef Carcass Size and Aging Time Effects on Yield and Color Characteristics of Top Round Steaks

Variation in cut size and weight of fabricated subprimals is a challenge of increased beef carcass weights. Subsequently, variation in carcass size has resulted in consistency challenges during retail display. The objective of this study was to assess three aging periods of commercially available top rounds from varying carcass weights as it relates to yield and color characteristics. In the current study, 21 industry average weight (AW; 340 to 409 kg; no industry discount) beef carcasses and 21 oversized (OS; exceeding 454 kg; receive a discount) beef carcasses were evaluated. Carcasses were selected at a commercial beef packing plant, where the left and right (paired) top round subprimals of each carcass were procured. Paired top rounds were assigned to a short (8 d), average (23 d), or extended (42 d) postmortem aging period. After wet-aging, subprimals were fabricated into steaks for additional analysis. Steaks were evaluated as whole top round steaks or further fabricated into “ superficial ” and “ deep ” portions at 5.08 cm from the superficial edge of the Semimembranosus and the Adductor muscle. Top rounds and steaks from OS carcasses were larger (P < 0.01) than those from AW carcasses. Quantitative color of the anatomically deep locations of the OS steaks had the greatest mean L* (lightness; P < 0.01), a* (redness; P < 0.01) and b* (yellowness; P < 0.01) values. Extending the aging timeline increased L* (lightness; P < 0.01), decreased a* (redness; P < 0.01), and decreased b* (yellowness; P < 0.01). Alternative top round steak fabrication that separates the deep and superficial anatomical locations could be an effective means of providing more uniform steaks.

Nutritional Profile of Donkey and Horse Meat: Effect of Muscle and Aging Time.

Simple SummaryHorse and donkey meat are a good source of nutrients and minerals. However, equine meat in many countries is still unpopular due to its toughness, although it has been demonstrated that an appropriate aging time improves the tenderness in different horse muscles. The present paper investigates the effect of aging time on nutritional properties in different muscles of horse and donkey meat. This information could represent an opportunity to valorize equine animal biodiversity and could be useful for the equine meat industry. The results highlight that horse and donkey meat, being particularly rich in PUFA and EAA, could represent healthy alternatives to traditionally consumed red meat. Aging time did not affect the nutritional profile of horse meat, whereas in donkey meat, a decrease of PUFA was observed after an aging time of 14 days.The aim of this study was to evaluate the effect of 14-day vacuum aging on the nutritional composition of donkey and horse meat. Longissimus Dorsi (LD), Semimebranosus (SM), and Rectus Femoris (RF), Semitendinosus (ST) muscles were sampled from each left carcass of 12 donkeys and 12 horses, respectively. Each muscle was divided into three sections, vacuum packaged, and stored at 2 °C for different aging times (1, 6, and 14 days). Fatty acids, amino acids, and cholesterol content were determined. SM exhibited higher levels of polyunsaturated fatty acids (PUFA) both in donkey and horse, whereas LD evidenced higher saturated (SFA) and monounsaturated (MUFA) fatty acids and lower cholesterol content in horse after 1, 6, and 14 days of storage. An aging effect was found only in donkey meat with higher saturated fatty acids and lower PUFA content at the end of the aging period. The highest value of essential amino acids has been displayed in SM an LD muscles from horse and donkey, respectively. Our results highlighted that equine meat, due to an excellent nutritional profile, represents a healthy alternative to traditionally consumed red meat. A different aging method could be used in donkey meat to preserve the high PUFA content.

Aging constants for efficient fracture toughness prediction of thermally aged GTAW/SMAW of 316L stainless steel

This paper presents closed-form expressions of the thermal aging constant to predict fracture toughness of thermally aged SMAW and GTAW 316 L stainless steels. Based on the data thermally aged at 350 °C up to 15,000 h and at 400 °C up to 8,000 h; and tested at room and operating temperatures (288 °C), closed-form approximations are given in terms of the aging time and temperature using an exponential function. Comparison of the predicted toughness with experimental data shows that the thermal aging time and temperature effects on toughness reduction can be predicted, although there exists quite scattering in experimental toughness data of weldment.