Influence Of Aging Process Research Articles

Influence of aging process and reinforcement ratio on physical and mechanical properties of carbonized aramid reinforced Al7075 materials

The high mechanical properties, corrosion resistance and low production costs of aluminum alloys make their use in the aerospace and automobile industries attractive. Addition of reinforcement, and heat treatment are important factors in increasing the physical and mechanical properties of these alloys. In this study, squeeze casting method was used to produce aramid reinforced Al7075 matrix materials and their mechanical, physical and microstructural properties were investigated. The physical (hardness) and mechanical (tensile, flexural) properties of Aramid/Al7075 material were compared with base alloy. Then, the effects of the aging process on the hardness, tensile and flexural strengths of 8%Aramid/Al7075 material (the best mechanical properties) and base alloy were investigated. The polished surfaces of the materials and the fracture surfaces after the tensile test were examined using Scanning Electron Microscopy (SEM), while the phase characterization after aging was performed using X-ray diffraction (XRD). The highest hardness values of non-aged materials were obtained in 12% aramid reinforced material. The highest flexural and tensile stress were obtained from 8% aramid reinforced material among non-aged materials, and their strengths were determined as 454 and 278 MPa, respectively. With an increase in aging time, the mechanical and physical properties of the materials exhibited a significant improvement. However, it was observed that these properties started to decrease after a certain aging time. In heat-treated Aramid/Al7075 materials, the lowest and highest hardness values were obtained as 184 and 205 HB, respectively, after aging for 8 and 20 h. The highest tensile strength (523 MPa) of the Al7075 alloy was obtained at the end of 20 h. The highest tensile strength of aramid reinforced material was obtained as 512 MPa at 16 h aging time.

Aging Processes and Their Influence on the Mechanical Properties of Printable Occlusal Splint Materials.

Three-dimensional (3D)-printed occlusal splints are becoming more prevalent in the treatment of tooth substance loss due to their fast and cost-effective production. The purpose of this in vitro study was to investigate whether the mechanical properties (tensile strength-TS, modulus of elasticity in tension-ME, and Vickers hardness-HV) vary between the materials (printed dimethacrylate-based resins: Keyprint KeySplint soft-KEY, Luxaprint Ortho Plus-LUX, V-Print splint-VPR, printed methacrylate-based resins Freeprint splint 2.0-FRE, and milled methacrylate-based material, CLEAR splint-CLE), and the influence of aging processes (extraoral storage conditions and nightly or daily use) was examined. The printed methacrylate-based resins (FRE, LUX, and VPR) had much higher TS (43.7-48.5 MPa compared to 12.3-13.3 MPa), higher ME (2.01-2.37 GPa compared to 0.43-0.72 GPa), and higher HV (11.8-15.0 HV compared to 3.3-3.5 HV) than both of the methacrylate-based resins (KEY and CLE) after the production process. Although the TS, ME, and HV of the printed dimethacrylate resins (FRE, LUX, and VPR) decreased significantly under humid conditions with possibly elevated temperatures (thermocycling as well as 37 °C), these mechanical properties were significantly higher than both methacrylate-based resins (KEY and CLE). Therefore, printed dimethacrylate resins should be used rather than methacrylate-based resins for high expected masticatory forces, low wall thicknesses, or very long wearing times (≥6 months).

Influence of aging process and restoration thickness on the fracture resistance of provisional crowns: A comparative study

BackgroundThe advancement of digital dentistry enhanced the fabrication of indirect provisional restorations utilizing durable materials, yet the performance of provisional crowns fabricated with various techniques, and different thickness remains unknown. Thus, this in-vitro study aimed to evaluate the influence of restoration thickness and aging on the fracture behavior of provisional crowns fabricated using different techniques. MethodsA dentiform maxillary first molar was prepared using a highly filled epoxy resin material to construct identical die replicas. Four groups of provisional crowns were fabricated: Group 1 was milled at 1.5 mm occlusal thickness; Group 2 was milled at 0.9 mm thickness; Group 3 was 3D-printed at 1.5 mm occlusal thickness; and Group 4 was 3D-printed at 0.9 mm occlusal thickness. Eight crowns from each group were subjected to a thermocycling process for 5000 cycles between baths held at 5 °C and 55 °C with a dwell time of 30 s and transfer time of 5 s. All crowns (aged and non-aged (control)) were loaded for fracturing using a universal testing machine at a 0.5 mm/min crosshead speed. Data were analyzed using a two-way analysis of variance and multiple comparisons at (α = 0.05). ResultsThe maximum mean force load was found in the non-aged milled group (M1.5) at 1706.36 ± 124.07 N; the minimum mean force load was recorded for the aged 3D-printed group (3D0.9) at 552.49 ± 173.46 N. A significant difference was observed before and after thermocycling (p < 0.01). ConclusionComputer-aided design and manufacture of milled provisional crowns is superior to 3D-printed crowns for fracture resistance.

Insights into influence of aging processes on zero-valent iron modified biochar in copper(II) immobilization: from batch solution to pilot-scale investigation

Insights into influence of aging processes on zero-valent iron modified biochar in copper(II) immobilization: from batch solution to pilot-scale investigation

Effect of heat treatment process on microstructure and properties of depleted uranium No.2 alloy

By controlling the heat treatment temperature, the influence of aging process on the microstructure and mechanical properties of depleted uranium No.2 alloy was studied, and the dynamic properties of No.2 alloy were analyzed by Hobkinson device, and the stress-strain relationship was tested. The results show that, after solution treatment at 850 °C × 2h and aging treatment at 350 °C × 4h, the microstructure of No.2 alloy is mainly U(γ) phase and U (α /), and the dynamic yield strength of the alloy reaches the peak, which can reach 1580MPa, which is more than 40% higher than the quasi-static yield strength and has a strong strain rate hardening effect.

Influence of aging processes on PE microplastics with various oxidants: Morphology, chemical structure, and adsorption behavior toward tetracycline

The presence of microplastics (MPs) in aquatic ecosystems and its capacity to load various environmental pollutants has garnered significant attention in recent years. Microplastics (MPs) are exposed to a variety of environmental aging processes, but the aging effect on fate of MPs in environment is poorly understood. In this study, the adsorption of tetracycline (TC) onto polyethylene (PE) MPs aged in different solutions, including H2O2, Na2S2O8, KMnO 4, and NaOCl was investigated. Aging processes were found to be responsible for surface oxidation of PE MPs, size reducibility, the production of new oxidation functional groups, and increased hydrophilicity. Based on the oxidation potential, the oxidizing agents were divided into a high-aging effect group (KMnO 4, NaOCl) and a low-aging effect group (H2O2, Na2S2O8). The adsorption capacities of MPs ranged from KMnO 4-PE (2.52 x 10−2 mmol g−1) > NaOCl-PE (2.07 x 10−2 mmol g−1)> PE (1.64 x 10−2 mmol g−1) >H2O2-PE (0.92 x 10−2 mmol g−1) > Na2S2O8-PE (0.28 x 10−2 mmol g−1). Chemical interactions, including such hydrogen bonding, and physical electrostatic attraction contributed to the adsorption of TC onto aged PE MPs. Also, parameters such as pH, temperature, and natural organic matter have a significant effect on the adsorption characteristics of aged PE MPs. This study reveals that aging microplastics may have a significant impact on the fate and mobility of pollutants, which calls for further research.

Effects of physical and chemical aging on polycyclic aromatic hydrocarbon (PAH) content and potential toxicity in rice straw biochars.

Polycyclic aromatic hydrocarbons in biochars threaten their environmental application. The aging process may affect the concentration of PAHs, potential toxicity, and the properties of biochar. In this study, the aged biochars were obtained by simulated physical aging method (freeze-thaw treatment) and chemical aging method (H2O2 chemical oxidation). The PAH contents in biochars were measured, and their potential toxicity was assessed. Meanwhile, the influence of aging process on the physicochemical properties of biochar was also investigated. This study shows that the change of PAH content of aged biochars depended on pyrolysis temperature, ambient temperature, and oxidant concentration. Furthermore, physical and chemical aging process influenced the distribution of different ring PAHs in biochars. High-ring-number PAHs (four, five, six-ring PAHs) appeared in some aged biochar. Aging at ±20 °C and 0.01 M H2O2 increased the toxic equivalent quantity of all biochars which may be attributed to the change of the physicochemical properties influencing the different PAH ring distribution in biochars. The contribution of PAHs with different rings to TEQ varied in pristine and aged biochars. Physical and chemical aging process significantly affected the properties of biochars, such as element content, ash content, surface area, pore volume, pH, functional groups, and surface morphology. Correlation analysis confirmed that surface area and pore volume are dominant factors determining the PAH content in the biochars. Therefore, the aging process indeed affected the PAH concentration and toxicity of PAHs in biochar. Assessing PAH behavior in biochar over long timescales should not be overlooked.

Insights into the Influence of Aging Processes on Zero-Valent Iron Modified Biochar in Cu(Ii) Immobilization: From Batch Solution to Pilot-Scale Investigation

Insights into the Influence of Aging Processes on Zero-Valent Iron Modified Biochar in Cu(Ii) Immobilization: From Batch Solution to Pilot-Scale Investigation

Influence of Aging Processes on the Biology and Outcome of Multiple Myeloma

Influence of Aging Processes on the Biology and Outcome of Multiple Myeloma

RESEARCH OF THE EFFECT OF AGING PROCESS ON DISPERSION OF AIR PHASE AND ICE CRYSTALS IN MILK ICE CREAM

In this research the results of analytical studies are presented, which prove the lack of data on influence of aging process on dispersion of structural elements in ice cream with fat mass fraction of 6% or less, and experimental studies on definition of dispersion of air phase and ice crystals in milk ice cream. It was found that the process of the mix aging doesn’t significantly affect the dispersion of air phase and ice crystals in ice cream with fat mass fraction of 3%. In ice cream with fat mass fraction of 6%, made from a mix, the dispersion of the air phase increased along with the aging process, and the size of almost all air bubbles were less than 50 microns. At the same time the dispersion of ice crystals increased by no more than 10%. The decrease in dispersion of the air phase during the storage period was observed, mostly in ice cream with a fat mass fraction of 6% produced of the cured mix. The research results have the practical importance as they justify the need for the aging process in the production of ice cream with a low mass fraction of fat and determine the necessity of further research in this area.

Sustainable machining by energy- and resource-efficient application of metalworking fluids

Due to increasing demands regarding the sustainability of manufacturing processes, a long service life and an energy-efficient supply of mineral-oil-based metalworking fluids is of increasing relevance. In the context of this work, the influence of aging processes in water miscible metalworking fluids on their performance has been investigated. Furthermore, results are presented regarding the energy-efficiency of metalworking fluid supply, which can be increased by adapting the fluid supply conditions.

Influence of the tempering temperature on the mechanical properties and the phase composition of thin sheet TRIP steel

The strength and the plasticity properties of sheet high-strength austenitic–martensitic VNS9-Sh TRIP steel (23Kh15N5AM3-Sh) are studied as functions of the tempering temperature in the range 125–600°C. A nonmonotonic decease in the strength and the plasticity properties of the steel has been detected when the tempering temperature increases, and they increase in the range 300–450°C. The influence of aging processes, the precipitation of carbide, and the phase transformations in tempering on the mechanical properties of austenitic–martensitic corrosion-resistant steel is discussed.

Effect of ageing time 200 °C on microstructure behaviour of Al-Zn-Cu-Mg cast alloys

Al-Zn-Cu-Mg is heat treatable alloy that can be used in many hightech applications, such as aerospace and military. The main objective of this study is to investigate the influence of ageing process in microstrucure behaviour of Al-9Zn-5Cu-4Mg cast alloy by performing SEM analysis and its correlation with hardness tests of as-cast Al-9Zn-5Cu-4Mg alloy and heat treated Al-9Zn-5Cu-4Mg cast alloy. The results show the deployment of precipitation spread over the dendrite and also the presence of second phases Mg 3 Zn 3 Al 2 , Cu 2 FeA l7 , CuAl 2 , and CuMgAl 2 in as-cast Al-9Zn-5Cu-4Mg alloy. The presence of all these second phases are affecting to the toughness of aluminium alloy and the presence of MgZn 2 leads the impairment of hardness value of heat-treated Al-9Zn-5Cu-5Mg cast alloy.

The Influence of Ageing Process on the Barium Aluminate Phase Composition

Barium aluminates were formed by the continuous precipitation method at different values of pH. The influence of ageing process and precipitation pH on the phase composition of the precipitate after firing was found. It was showed that there is growth of the 3BaOAl 2 O 3 concentration after ageing of precipitate during 7 days. Presumably, this process is associated with a decrease in the number of crystals, increasing their size in the ageing process of precipitate and chemical processes that occur during ageing: hydrolysis, hydration, dehydration.

Influence of aging process on arginine (Arg) and its derivatives – asymmetric and symmetric dimethylarginine (ADMA, SDMA) in rat liver subjected to ischemia/reperfusion (IR)

Influence of aging process on arginine (Arg) and its derivatives – asymmetric and symmetric dimethylarginine (ADMA, SDMA) in rat liver subjected to ischemia/reperfusion (IR)

Influence of ageing processes on the structure and physical properties of amorphous-crystalline films of Gd&lt;196&gt;Fe system

Influence of ageing processes on the structure and physical properties of amorphous-crystalline films of Gd&lt;196&gt;Fe system

Influence of ageing process on body composition of antioxidant and lipid peroxidation among healthy individuals in South West Nigeria

To evaluate the effect of ageing on the level of antioxidants and lipid peroxidation in healthy individual of various age groups. A total number of 162 healthy males and females volunteer between the ages of 18-80 years were divided into three groups. These volunteers were divided into group i(18-30 yr), group ii (31-60 yrs) and group iii (60-80 yr). Plasma concentration of total bilirubin, uric acid, ascorbic acid, a-tocopherol, retinol, total antioxidant status (TAS), malondialdehyde (MDA), glutathione (GSH) and ceruloplasmin measured. Erythrocyte antioxidant enzyme activities of superoxide dismutase (SOD), catalase (CAT), glutathione and peroxidase (GSHPx) were measured using standard methods. Erythrocyte antioxidant enzymes (GSH-Px and SOD) activities and GSH level were significantly reduced among group iii (p<0.01) and group ii (p<0.05) age group subjects compared to the younger age group i. Conversely, MDA showed a significant increase in group iii (p<0.01) and group ii (p<0.01) compared to younger age group i. CAT activity and TAS level were reduced significantly (p<0.05) in both groups iii and ii compared to younger age group i. Ascorbic acid, a-tocopherol and retinol levels were significantly reduced among group iii (p<0.05) compared to group i. Ageing was associated with increased lipid peroxidation and lower antioxidant defenses. Changes that occur during ageing cannot be avoided but may be delayed and controlled to some extent. To counter these changes, dietary supplementation of a variety of antioxidants might be beneficial.

Structural stratification of Sr1 − xCaxRuO3 thin films: Influence of aging process

AbstractEpitaxial Sr1 − xCaxRuO3 thin films were grown on SrTiO3 and LaAlO3 substrates with use of high pressure dc‐sputtering. A number of complementary methods: X‐ray diffraction (XRD), Rutherford backscattering (RBS), high resolution transmission electron microscopy (HRTEM), time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS), atomic force microscopy (AFM), and X‐ray photoemission spectroscopy (XPS) was used to characterize both in‐depth and lateral structure features.Fully strained thin films were obtained with a tetragonal lattice cell pronouncedly elongated in an out‐of‐plane direction, independent on details of deposition conditions. Growth types varied from a single layer‐by‐layer two‐dimensional (2D) mode to three‐dimensional (3D) spiral precipitations of different size. Interface layer between the substrate and the thin film as well as its surface suffer from considerable deviations from nominal stoichiometry, basically resulting from Ru deficiency. Samples stored under normal conditions undergo further compositional change of the surface region. The process of aging, extended over several days, involves incorporation of water and carbon dioxide present in an ambient atmosphere and a subsequent surface reconstruction. For samples deposited on SrTiO3 the valence band is indicative of a metallic character of the sample interior regardless of Ca content. The heterogeneous in‐depth profile of the thin films is extremely important in fabrication of nanodevices, especially those based on ultrathin layers. magnified image Examination summary of Sr0.8Ca0.2RuO3 thin films, deposited on SrTiO3, methods used and essential conclusions.

Experimental analysis of creep and fatigue of light multifunctional aluminium alloys

The paper presents experimental investigations of two light aluminium alloys (AlSi8Cu3 and AlSi7MgCu0·5) under loading conditions leading to the creep or fatigue processes. During the creep process, the strains were measured under selected tensile stresses and temperatures. An influence of a step loading during creep, at elevated temperature, on steady creep rate and a course of creep curve, was investigated. Moreover, an effect of porosity degree on creep of both aluminium alloys was also analysed. An influence of aging process at the elevated temperature was experimentally evaluated. Fatigue behaviour of materials was checked under strain control using cylindrical samples. The results of LCF tests were analysed for the materials subjected to three‐stage sequence of loading at elevated temperature. A resistance to creep and fatigue processes of the AlSi8Cu3 was weaker than that obtained in the case of the AlSi7MgCu0·5.

Artificial ageing of softwood joints and its effect on internal bond strength with special consideration of flat-to-end grain joints

The effect of ageing processes on internal bond strength of three-part specimens produced from Norway spruce wood (Picea abies Karst.) bonded with one-component polyurethane (PUR), two-component emulsion polymer isocyanate (EPI), melamine-urea-formaldehyde (MUF) or phenol-resorcinol-formaldehyde (PRF) adhesive was studied. By varying the grain angle of the middle part from 0° (parallel to grain of the surface layers) to 90° (perpendicular to grain of the surface layers) in incremental steps of 10° the effect of grain direction was investigated. The specimens were exposed to a three-step ageing cycle lasting for seven days (50°C/95% relative humidity (rH), −20°C/65–70% rH and 75°C/15% rH) which was repeated twelve and twenty-four times, respectively. In general, a decrease in internal bond strength of the exposed specimens was observed. For all tested adhesive systems, influence of ageing processes was more pronounced for flat-to-end grain joints compared to longitudinal joints. For samples bonded with PUR adhesive strength reduction was lower compared to the other adhesives used.