Effect Of Temperature Research Articles

A Kinetic Study of Silver Extraction from End-of-Life Photovoltaic Panels through Gold-REC1 Process

Recycling materials from end-of-life devices and products is becoming increasingly a fundamental activity for the sustainable development of nations. With the return from the market of immense quantities of photovoltaic panels at the end of their life, it is essential to foresee processes for recovering and valorizing all the raw materials present in them to avoid wasting important flows of raw materials. This research introduces a novel process aimed at the recovery of silver and silicon from end-of-life photovoltaic panels. The leaching efficiency and kinetics of ground cake powder in sulfuric acid, ferric sulfate, and thiourea were investigated in the leaching system. In particular, the influences of significant parameters, including particle size, leaching temperature, and stirring rate, on the extraction kinetics were analyzed using the shrinking core model. The results showed silver dissolving mechanisms, in which more than 90% of silver recovery at 60 min of reaction time and 99% at 120 min was achieved (120 rpm, 53–125 µm, and 40 °C). The significant effect of the leaching temperature suggests that the process is under the control of the chemical reaction. Moreover, these results were confirmed by the regression analysis of the experimental data with the shrinking core model. It can be concluded that this newly proposed process, called Gold-REC1, allows the recovery of Ag and Si (solid residue from the process) with extremely high yields and rapid kinetics. The obtained results can provide fundamental data for developing end-of-life photovoltaic recycling on an industrial scale.

SONOCHEMICAL SYNTHESIS OF SILVER NANOPARTICLES FOR GAS-DIFFUSION ELECTRODES APPLICATION

The aim of the current study is to explore the application of silver nanoparticles (AgNPs) as a catalyst in air gas-diffusion electrodes (AGDE). AgNPs have been successfully synthesized through an original sonochemical method. The effects of reagent concentrations, temperature and reaction time were studied as well. Composites of AgNPs and activated carbon (Norit NK) were prepared by using two adsorption methods to demonstrate the catalytic activity. Method 1 involves homogenizing preliminary prepared AgNPs colloid solution and Norit NK followed by evaporation of the suspension. One-step route was used for Method 2, i.e. all components were mixed altogether and sonicated, resulting in the AgNPs formation directly on the surface and inside the pores of Norit NK. Additionally,some of the samples were thermally treated at 300°C for 1h under air and argon. The composites were characterized by X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-Ray analysis (SEM/EDX) and transmission electron microscopy (TEM). The catalytic activity of the obtained composites regarding oxygen reduction reaction (ORR) was investigated in AGDE using an aqueous 4M NaCl electrolyte. The thermally treated composite obtained via Method 2 appears to show improved electrochemical catalytic activity regarding ORR in comparison to the Method 1 samples.

Effect of Solution Treatment Temperature on Microstructure, Mechanical Properties and Corrosion Resistance of Ultra-High Nitrogen Stainless Steel

Effect of Solution Treatment Temperature on Microstructure, Mechanical Properties and Corrosion Resistance of Ultra-High Nitrogen Stainless Steel

Uniaxial compression stress–strain relationship of fully aeolian sand concrete at low temperatures

Abstract The aim of this study is to investigate the impact of various ambient temperatures on the mechanical properties of full aeolian sand concrete (ASC100). Using ordinary concrete (ASC0) as the control group, we analyzed the effects of different ambient temperatures (−20, −15, −10, −5, 0, and 20°C) on the mechanical properties of both ASC0 and ASC100 through cube compression, splitting tensile, and uniaxial compression tests. The results demonstrate that the compressive strength and splitting tensile strength of concrete cubes increased with decreasing temperature. At −20°C, the compressive strength of ASC100 increased by 30.1% and that of ASC0 increased by 27.31% compared to that at 20°C. Additionally, compared to normal temperatures, the elastic modulus of ASC0 and ASC100 at subzero temperatures increased by 28.2–61.4% and 6.8–65.7%, respectively, while the peak stress increased by 7–35% and 6.8–38%, respectively. The stress–strain curve of ASC100 showed three stages: elastic, elastic-plastic, and yield failure, serving as the reference group. Finally, based on the classical constitutive model, we modified the constitutive parameters by axial compressive strength and temperature, proposing a constitutive model of concrete suitable for different low-temperature environments, which is in good agreement with experimental data.

An investigation of CO generation path upon loading coal from perspective of macromolecular simulation.

CO is a hazardous and pollutant gas that can be produced in many scenarios of coal-related operations. The study mainly investigated CO production process and mechanism when coal is subject to external forces. The effects of coal type, particle size, temperature, and inlet atmosphere on CO production from coal body fragmentation were investigated through coal loading experiments. Materials Studio software was used to carry out coal macromolecular mechanics simulation and molecular dynamics simulation, and the gas production mechanism of coal under loading was explored at the molecular level. It was found that under air atmosphere, the low degree of deterioration, small particle size, and elevated temperature are all more likely to cause coal samples to fragment and decompose to produce CO. The carbonyl group in the molecular structure of coal is shed or broken free radical fragments react with oxygen which may lead to CO formation.

Effect of Calcination Temperature on the Surface of Prepared ZnO Nanocatalysts

ZnO nanoparticles (NPs) having nsemiconducting properties are important nanocatalysts for many surface reactions. Because of their extensive use as heterogeneous nanocatalyst for energy production and environmental cleaning, it is essential to understand their surface properties to design better chemical and photochemical nanocatalysts. Here, we used the sol-gel method to develop numerous ZnO NPs at various calcination temperatures (300 - 800 oC) and analyzed by different surface characterization techniques such as FTIR, SEM, XRD and UV-visible absorption spectroscopy. To investigate the catalytic activity a series of photooxidation studies on Remazol Red RR (RRR) were carried out at different conditions. From the surface characteristic analysis, it is found that the crystalline ZnO NPs are formed at above 400 oC temperature. The highest photocatalytic efficiency is found at 500 oC which might be related to the lowest particle size (35.4 ± 5.2 nm) and surface heterogeneity. The experimental results suggest that temperature-controlled growth rate and intra/inter-particle heterogeneity of ZnO nanoparticles have a great impact on the surface properties and photocatalytic activity. In addition to surface area, surface defects and crystal deformation may have a considerable impact on the photocatalytic activity by ZnO NPs. Finally, this study will help to understand what type of surface properties need to optimize to design industrial suit ZnO nanocatalysts. Journal of Engineering Science 15(1), 2024, 75-81

Factors Affecting the Indoor Air Quality and Occupants’ Thermal Comfort in Urban Agglomeration Regions in the Hot and Humid Climate of Pakistan

The World Air Quality Index indicates that Pakistan ranks as the third most polluted country, regarding the average (Particulate Matter) PM2.5 concentration, which is 14.2 times higher than the World Health Organization’s annual air quality guideline. It is crucial to implement a program aimed at reducing PM2.5 levels in Pakistan’s urban areas. This review paper highlights the importance of indoor air pollution in urban regions such as Lahore, Faisalabad, Gujranwala, Rawalpindi, and Karachi, while also considering the effects of outdoor air temperature on occupants’ thermal comfort. The study aims to evaluate past methodological approaches to enhance indoor air quality in buildings. The main research question is to address whether there are statistical correlations between the PM2.5 and the operative air temperature and whether other indoor climatic variables have an impact on the thermal comfort assessment in densely built urban agglomeration regions in Pakistan. A systematic review analysis method was employed to investigate the effects of particulate matter (PM2.5), carbon oxides (COx), nitrogen oxides (NOx), sulfur oxides (SOx), and volatile organic compounds (VOCs) on residents’ health. The Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) protocol guided the identification of key terms and the extraction of cited studies. The literature review incorporated a combination of descriptive research methods to inform the research context regarding both ambient and indoor air quality, providing a theoretical and methodological framework for understanding air pollution and its mitigation in various global contexts. The study found a marginally significant relationship between the PM2.5 operative air temperature and occupants’ overall temperature satisfaction, Ordinal Regression (OR) = 0.958 (95%—Confidence Interval (CI) [0.918, 1.000]), p = 0.050, Nagelkerke − Regression (R2) = 0.042. The study contributes to research on the development of an evidence-based thermal comfort assessment benchmark criteria for the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Global Thermal Comfort Database version 2.1.

Anthropogenic and environmental risk factors of salmonid predation in a tidal freshwater delta

Abstract Water diversions that support agricultural and municipal use result in fish mortality through entrainment and impingement. Additionally, this infrastructure may attract both predators and prey fishes, thereby increasing predation rates and prey mortality near these anthropogenic contact points. The Sacramento–San Joaquin Delta (the Delta) in California's Central Valley is a tidal freshwater ecosystem that exports large volumes of water for municipal and agricultural use while at the same time providing valuable migratory and rearing habitat for imperilled fishes. Emigrating juvenile salmonids experience high mortality in the Delta, with predation by non‐native fishes contributing substantially. Therefore, this study had three main objectives. First, we determined if small water diversions aggregated piscivorous fishes like other similar structures in freshwater ecosystems. Second, we determined how small diversions may influence juvenile salmon predation risk in conjunction with other known predation risk factors (e.g. predator abundance, temperature and depth). Third, we assessed the predator assemblage, abundance and distribution to determine the likely predator composition in objectives one and two. Throughout the spring of 2021, we used ARIS (adaptive resolution imaging sonar; Sound Metrics) sonars to compare piscivore abundance at 30 water diversions in the north Delta to shorelines adjacent to diversions that did not contain these structures. We used predation event recorders (PERs) to assess the predation risk juvenile salmonids were exposed to, with linear distance (m) from diversions, and other predation risk factors in the north Delta. Finally, we used a boat electrofishing survey to determine the piscivore assemblage and compare spatial trends in black bass (Micropterus spp.) CPUE and relative abundance throughout these waterways. Piscivore abundance was greater near small water diversions than at adjacent shorelines and the predation risk of juvenile salmonids increased with diversion proximity. Additionally, predation risk increased with increasing piscivore abundance and decreasing water depth. The north Delta predator assemblage was dominated by black basses (Micropterus spp.), which likely drove the negative relationship of predation risk with water depth, given habitat requirements of these species. Furthermore, increasing smallmouth (Micropterus dolomieu) and spotted bass (Micropterus punctulatus) abundance in our northern study sites may have weakened temperature effects on predation, given metabolic requirements of these species. Our work demonstrated that small water diversions are likely to increase mortality of endangered salmonids, and that the north Delta predator assemblage was different than recorded by previous work in this system, changing predation risk factors. Although more work is needed to determine the population level impacts of diversions, the ubiquitous distribution of these structures warrants management solutions to reduce mortality from this source. These results indicate that in addition to entrainment and impingement, water diversions may increase mortality of small‐bodied fishes by attracting predators and elevating predation risk. Given the continual human demand for freshwater, predator–prey interactions should be considered along with entrainment and impingement when assessing intake infrastructure mitigation, especially when diversions co‐occur along migratory routes and essential habitat of imperilled fishes.

Efficiency Optimization of LCL-Resonant Wireless Power Transfer Systems via Bidirectional Electromagnetic–Thermal Coupling Field Dynamics

This paper delved into the thermal dynamics and stability of Wireless Power Transfer (WPT) systems, with a focus on the temperature effects on the coil structure. Using the Finite Element Method (FEM), this study investigated both unidirectional and bidirectional coupling field simulations, assessing their impacts on the transmission efficiency of LCL-resonant WPT systems. The boundary conditions and processes of the electromagnetic–thermal coupling field related to coil loss were analyzed, as well as the dynamic thermal balance in the bidirectional coupling field model. It was found that there is a significant temperature variation across the coil, with the highest temperatures at the central position and the lowest at the edges. This temperature rise notably changed the electrical parameters of the system, leading to variations in its operating state and a reduction in transmission efficiency. A constant coil voltage control strategy was more effective in mitigating the temperature rise compared to a constant coil current strategy, providing valuable insight for enhancing the efficiency and stability of WPT systems.

Experimental investigation on mechanical property and hydration process of sintered sludge cement paste at different water‐binder ratios and curing ages

AbstractThis research investigated the mechanical property and hydration process of sintered sludge cement (SSC) paste, focusing on the effects of calcination temperature of sludge, sintered sludge ash (SSA) content, curing age, and water‐binder ratio using isothermal calorimetry, X‐ray diffraction, scanning electron microscopy, and multiple regression. Increasing calcination temperature enhanced the compressive strength of SSC paste due to the decomposition of minerals like Clinochlore and Muscovite. The compressive strength decreased by 2.4%–49.4% when the SSA content increased from 0% to 50%, with more significant declines noted at higher water‐binder ratios. Notably, the 7‐day compressive strength of the cement paste with 10% SSA showed little change, and the 28‐day compressive strength actually increased at a water‐binder ratio of 0.4. SSA slowed down the hydration rate of cement and induced more Monocarbonate to form in the early stage. A multiple linear regression model was developed to predict SSC compressive strength with a 12% error margin.

Dihydrorhodamine-123 flow cytometry method: time for substantial revision in technical procedure.

The dihydrorhodamine 123 assay is generally applied to measure the production of intracellular reactive oxygen species in neutrophils using flow cytometry and is considered a diagnostic evaluation for chronic granulomatous disease. In fact, there is a broad range of variables that can directly or indirectly affect test results, either individually or collectively. It is therefore crucial to identify the ideal requirements to achieve reliable results as well as using these requirements to provide standard operating procedures that should be taken into account. Therefore, we focus on aligning optimum results by comparing preanalytical and analytical phases that influence test results, such as the effect of various anticoagulants, transport and maintaining temperature (24°C or 4°C) of samples, test prime run time, appropriate solution concentrations, and effect of incubation temperature (24°C or 37°C) during the test run.

Temperature dependence of leaf breakdown in streams differs between organismal groups and leaf species.

Increased temperatures are altering rates of organic matter (OM) breakdown in stream ecosystems with implications for carbon (C) cycling in the face of global change. The metabolic theory of ecology (MTE) provides a framework for predicting temperature effects on OM breakdown, but differences in the temperature dependence of breakdown driven by different organismal groups (i.e., microorganisms vs. invertebrate detritivores) and litter species remain unresolved. Over two years, we conducted 12 60-day leaf litterbag incubations in 20 headwater streams in the southern Appalachian Mountains (USA). We compared temperature dependence (as activation energy, Ea) between microbial and detritivore-mediated breakdown, and between a highly recalcitrant (Rhododendron maximum) and a relatively labile (Acer rubrum) leaf species. Detritivore-mediated breakdown had a higher Ea than microbial breakdown for both leaf species (Rhododendron: 1.48 > 0.56 eV; Acer: 0.97 > 0.29 eV), and Rhododendron breakdown had a higher Ea than Acer breakdown for both organismal groups. Similarly, the Ea of total (coarse-mesh) Rhododendron breakdown was higher than the Ea of total Acer breakdown (0.89 > 0.52 eV). These effects for total breakdown were large, implying that the number of days to 95% mass loss would decline by 40% for Rhododendron and 26% for Acer between 12°C (our mean temperature value) and 16°C (+4°C, reflecting projected increases in global surface temperature due to climate change). Despite patterns in Ea, overall breakdown rates were higher for microbes than detritivores, and for Acer than Rhododendron over most of our temperature gradient. Additionally, the Ea for a subset of the microbial breakdown data declined from 0.40 to 0.22 eV when fungal biomass was included as a model predictor, highlighting the key role of fungi in determining the temperature dependence of litter breakdown. Our results imply that, as streams warm, routing of leaf litter C to detritivore-mediated fates will increase faster than predicted by previous studies and MTE, especially for labile litter. As temperatures rise, earlier depletion of autumn-shed, labile leaf litter combined with rapid breakdown rates of recalcitrant litter could exacerbate seasonal resource limitation and alter carbon storage and transport dynamics in temperate headwater stream networks.

Investigate Performance of ATGF nanocomposite based on guar gum polymer for adsorption of Congo Red dye and alpha lipoic acid drug from wastewater: study kinetics and simulation

AbstractIn this study, the synthesized nanocomposite novel arginine/thiourea/guar gum/ferrite (ATGF) adsorbent was evaluated for the adsorption of alpha lipoic acid (ALA) and Congo Red (CR) from wastewater. The synthesized nanocomposite was examined by Brunauer–Emmett–Teller theory (BET), Termal gravimetric analysis (TGA), Fourier transform infrared spectrometer (FT‐IR), field emission scanning electron microscopy (FE‐SEM), X‐ray Diffraction (XRD), Vibrating sample magnetometer (VSM), and energy dispersive X‐ray (EDX). For the removal of ALA and CR from aqueous solution, the capacity of the nanocomposite was investigated by working on a series of experiments such as the effect of adsorbent dose, initial concentration, contact time, pH and temperature. The adsorption kinetics of these two pollutants were investigated using pseudo‐first‐order and pseudo‐second‐order velocity equations. The nanocomposite kinetics follow pseudo‐second‐order. Langmuir and Freundlich isotherms were investigated. The results show that the Langmuir isotherm model gives the maximum adsorption capacity of ALA as 96.93 mg g−1 and of CR as 229.34 mg g−1 on the nanocomposite. © 2024 Society of Chemical Industry.

Thermal buckling analysis of reinforced composite conical shells in acidic environments: Numerical and experimental investigation on the effects of nanoparticles

This study investigates the effects of acid penetration and temperature on the buckling behavior of conical composite shells, to enhance structural integrity and longevity in corrosive environments. The study explores the impact of acid exposure on thermal properties and examines the efficacy of incorporating nano-silica and nano-clay in preventing buckling. Additionally, it analyzes the influence of nanoparticles on the thermal, moisture, and mechanical properties of the composite material. Experimental assessments are conducted to measure material properties during exposure to a sulfuric acid solution, providing a comprehensive understanding of the material's behavior under extreme conditions. However, due to the complexity of investigating the combined effects of temperature, acid, and nanoparticles on composite shell buckling, a combined numerical and experimental approach is adopted to predict the critical buckling load. To this end, equations of conical shells under hygrothermal loading are derived, and the critical buckling load is determined through pre-buckling analysis. The Generalized Differential Quadrature (GDQ) method is employed to solve the hygrothermal buckling of the composite shell using experimentally obtained material properties. Comparative results are presented for different nanoparticles, shell geometries, and exposure times in acidic environments. The experiments reveal that adding nanoparticles enhances mechanical properties and reduces thermal and moisture expansion coefficients. Conversely, the acidic conditions deteriorate these properties. Numerical analysis demonstrates that incorporating nanoparticles significantly increases the critical buckling temperature, with nano-silica and nano-clay particles resulting in an 11.5 % and 34.2 % increase, respectively. However, acidic environments decrease the critical buckling temperature, with reductions of 32 % for unreinforced, 29 % for nano-silica reinforced, and 46 % for nano-clay reinforced composites after three months of exposure.

The novel stereoscopic cooling plate designs and performance analysis for battery thermal management systems

This study explores the design and performance of liquid cooling plate-based battery thermal management system for lithium-ion battery packs through numerical simulation. We first assess traditional straight-channel cooling plates with three different placement strategies. The conventional design with bottom-mounted cooling plates demonstrates the most effective thermal management at the same total coolant mass flow rate. This suggests that the influence of reducing coolant flow velocity on the cooling performance outweighs the influence of increasing the heat exchange area under our simulated conditions. Advanced stereoscopic cooling plate structures, referred to as 3DCP-A and 3DCP-B, are then introduced, significantly enhancing battery thermal management performance. To achieve a maximum temperature difference ≤ 5.0 K for the most discharge process, the required mass flow rate of the 3DCP-B decreases by 30.0 g∙s−1 and 10.0 g∙s−1 compared to the conventional bottom-mounted cooling plate and 3DCP-A, respectively, and the pressure drop reduces by 75.9 % and 44.3 %, respectively. The power consumption for the 3DCP-B design is only 6.0 % of that for the traditional design. Finally, the effects of key operating temperatures on the cooling performance of the optimal 3DCP-B design are discussed. The insights obtained in this study provide valuable guidance for developing more efficient and effective pack-level liquid cooling plate-based battery thermal management system, essential for improving the reliability and performance of electric vehicles.

The Effect of Different Storage Temperatures over Time on the pH of Mammary Gland Secretions in Periparturient Mares.

The objectives of this study were (i) to determine pH and electrolyte concentrations in MGS collected prepartum and at parturition, (ii) to characterize mare milk pH during the first week postpartum, and (iii) to evaluate pre-foaling MGS pH at three storage temperatures. This study outlined two hypotheses: (i) all mares exhibit acidic pH, increased calcium, magnesium, and potassium, and reduced sodium concentrations regardless of prepartum pH and electrolytes; (ii) pre-foaling MGS pH varies with storage temperature and time in an initial value-dependent manner. Twenty-three multiparous mares were monitored daily from 320 days of gestation until parturition. Pre-foaling MGS was collected, and pH was immediately measured using a hand-held pH meter. Aliquots were preserved for further electrolyte analysis. Postpartum, samples from day -7 to 0 (day of foaling) were thawed, and electrolyte concentrations (calcium, magnesium, sodium, potassium) were determined. For the three storage temperatures, pH was measured at 0, 15, 30, 45, and 60 min after storage, and hourly for 10 h post-collection. A range of pH 8 to 6.5 was included to avoid bias towards a specific pH value. The chosen pH groups were 8 (range 7.8-8.2), 7.5 (range 7.3-7.7), 7 (6.7-7.2), and 6.5 (6.2-6.6). Overall, storage temperature affects pH (p < 0.05). In conclusion, this study demonstrated that the majority of the mares had sodium-potassium inversion and acidic pH at foaling. Milk pH is neutral up to four days after foaling, becoming slightly alkaline afterwards, with undetermined clinical significance. The pH of MGS showed minimal variation across storage temperatures, except for pH ~7.5, which increased to ~8 post-storage. This study is the first to address these physiological and practical questions about MGS pH in periparturient mares.

Preparation and Performance Study of Ultraviolet-Responsive Self-Healing Epoxy Asphalt.

In this study, a self-healing epoxy asphalt material was developed by incorporating coumarin groups. This material achieved microcrack self-repair under UV irradiation at 50 °C. Fluorescence microscopy observations and mechanical performance tests demonstrated significant advantages in crack filling and mechanical property recovery after repair, with the fracture toughness of the repaired epoxy asphalt reaching 69% of that in its original state. Furthermore, the synergistic effect of temperature and UV irradiation in the self-healing process enhanced the material's durability and service life. This research offers new insights and methods for developing more durable and long-lasting self-healing asphalt materials, showcasing the great potential of smart materials in infrastructure applications.

Effect of Temperature and Initiator Concentration on the Curing Reaction of an Epoxy/Amine System

AbstractEpoxy blends of diglycidyl ether of bisphenol A (DGEBA) and 2‐[2‐(dimethylamino) ethoxy] ethanol (DMAEE) were prepared. The effect of DMAEE concentration on the rheological properties of the epoxy blends were investigated through oscillatory rheometry under isothermal conditions. A novel technique was developed to study the rheological behavior of the epoxy blends by using a Rubber Process Analyzer (RPA). The rheological study enabled analyzing the variations in the storage modulus (G’), loss modulus (G’’) and torque during the progress of the curing reaction. Additionally, the theoretical cross‐linking density (νe) and the degree of conversión of the curing reaction (α). The gel time (tgel) was determined at different temperatures, and the activation energy (Ea) was calculated by using Arrhenius‐type equation based on the gel time results. The activation energy values found are 24.79 kJ/mol and 23.01 kJ/mol. The results obtained are consistent with the values described in the literature. It was demonstrated that the proposed methodology is valid and, the use of the tertiary amine DMAEE curing agent for epoxy resins was confirmed.

Biophysical Properties of Thermostable Amidase Produced by Aspergillus fumigatus in Submerged Fermentation

Amidases, also known as amidohydrolases (EC 3.5.1.4), are enzymes within the nitrilase superfamily or amidase signature family. They hydrolyze amides and nitriles into their corresponding acids while releasing ammonia. These enzymes are widely used in biotechnology and industry. However, their production is limited to a few organisms, which cannot meet industrial demand. Therefore, exploring new amidase sources is crucial. This study focuses on purifying and characterizing amidase from Aspergillus fumigatus using cold acetone precipitation and column chromatography with Sephadex G-100. The effects of temperature, pH and metal ions, on the enzyme activity were examined for both crude and purified amidase. The thermal and pH stability of the enzyme alongside the enzyme kinetics were also assessed. The purified amidase exhibited optimal activity of 13.1 U/mL at 70°C, with 65% residual activity after 5 hours at this temperature. The pH studies showed optimal activity at pH 5.0 for the purified enzyme (7.8 U/mL) and at pH 4.0 for the crude enzyme (5.5 U/mL). Metal ion effects indicated that Zn²⁺, Mg²⁺, and EDTA enhanced, while Cu²⁺ inhibited, the activities of both crude and purified amidase. Kinetic analysis showed that the enzyme followed Michaelis-Menten kinetics, with Km and Vmax values of 0.104 mM and 1.884 U/mL for crude amidase, and 0.017 mM and 1.872 U/mL for purified amidase. These findings suggest that amidase from Aspergillus fumigatus holds potential for industrial applications where amidases are essential.

Thermal deformation behavior of a Ni-Cr-Fe superalloy and its effect on corrosion resistance: A comprehensive analysis of strain rate and temperature effects

Thermal deformation behavior of a Ni-Cr-Fe superalloy billet were investigated by hot compression experiments under temperatures of 900–1200 °C and strain rates of 0.001–1 s−1, and the corrosion properties of the superalloy after thermal deformation were also evaluated by electrochemical tests. Compression experiments determined that lower strain rates and higher temperatures reduce the superalloy's stress levels. The Arrhenius-type model accurately described the thermal deformation behavior of the superalloy. Furthermore, the optimal hot working domain was identified between 1120 and 1170 °C and strain rates of 0.001–0.01 s−1. Microstructure observations showed that the dynamic recrystallization (DRX), characterized by grain boundary bending nucleation and consumption of numerous dislocations is the main mechanism leading to grain refinement during thermal deformation. The results of the electrochemical corrosion tests proved that the corrosion predominantly occurred near the grain boundaries (GBs) of deformed grains, worsening with increased deformation temperatures.