High Material Costs Research Articles

Concurrent and Aerobic Exercise on Maximal Oxygen Consumption in Adults with Obesity: Study Protocol for a Randomized Controlled Trial

Background. Concurrent and aerobic physical exercise are strategies for treating overweight and obesity. Most interventions have utilized cardiovascular or guided execution machines, which often involve high-cost materials not easily accessible to the general population. Objective. Identify the effect of 12 weeks of exercise (concurrent vs. aerobic training) based on the polarized training intensity distribution model on maximal oxygen consumption, muscle strength, and body composition. Materials and methods. A randomized controlled trial with two groups, concurrent vs. aerobic training (n = 28), in overweight and obese individuals. Both groups will perform 36 sessions, 3 times a week, on alternate days. Results. Current evidence has not demonstrated the superiority of concurrent over aerobic exercise on VO2max, muscle strength, and body composition. Additionally, the few randomized studies with concurrent exercise and the methodological limitations in their designs justify the importance of comparing both types of exercise to determine the best strategies for overweight and obese individuals regarding the mentioned outcomes.

Recent progress in research and development of rare-earth free iron nitride permanent magnet

The high cost of rare earth materials, unstable supply and high demand remain big problems to solve for permanent magnet industries. Thus α″-Fe16N2 has been picked up as one of the most promising rare earth-free magnet candidates because of its use of environmental-friendly raw materials, confirmed giant saturation magnetic flux density (2.9 T), and reasonably high magnetic anisotropy constant (1.8 MJ/m3). Also, α”-Fe16N2 metastable with film form exhibits high tetragonality (c/a=1.1) by interstitial introduction of N atoms, leading to a high magnetocrystalline anisotropy constant (Ku = 1.0 MJ/m3). but synthesis of bulk form has lower properties than thin film (<230 nm) because of magnetic interaction, experimentally low anisotropy, and low density. In this paper, we review the synthetic methods of metastable α”-Fe16N2 with powder and bulk form and discuss the approaches to enhance magnetocrystalline anisotropy of α”-Fe16N2.

Preliminary study of mixing used cooking oil and lemon peel essential oil as an alternative fuel to replace biodiesel

Biodiesel is an environmentally friendly renewable bio-energy with many advantages over diesel fuel. The disadvantage of biodiesel is that the price is still relatively expensive so it cannot compete with diesel fuel. This high price is due to the high cost of raw materials and manufacturing process costs. Raw materials such as palm oil, methanol and methyl acetate are expensive, and the transesterification and interesterification processes require long process stages that require a lot of energy supply. The solution to overcome this problem is to use cheap raw materials and a simple manufacturing process. Used cooking oil is household waste that has prospects as a raw material. Another ingredient used is lemon essential oil. Lemon essential oil can be made yourself by extracting lemon peel waste using a boiling or steaming process. The lemon essential oil used is also small, namely a maximum of 5% of the mass of used cooking oil. It is hoped that mixing used cooking oil with lemon essential oil can replace biodiesel. Lemon essential oil is a bio-additive that can improve the quality of used cooking oil to approach the physical properties of biodiesel. With this new process, it is hoped that it can produce fuel that is cheap but of good quality. The aim of the research is to obtain a new fuel to replace biodiesel that is cheaper and more efficient, namely with cheap raw materials and fewer process stages so that it will reduce production costs. The research began with the activation of zeolite as an adsorbent for purifying used cooking oil with variables including zeolite mass of 400 grams, calcination temperature of 300⁰C, activation time of 2 hours and zeolite size > 80 mesh. The second stage of the research was purifying used cooking oil with zeolite using a variable volume of 3 liters of used cooking oil and a purification time of 1 hour. The third stage of the research was mixing purified used cooking oil with lemon essential oil with variable volume of essential oil (3, 4, 5, 6, 7% oil volume) and mixing temperature (30, 40, 50⁰C), mixing time 60 minutes, stirring speed 500 rpm and oil volume 150 mL. After the mixing time and the sample temperature reached room temperature, an analysis of the density, acid number, viscosity and FFA of used cooking oil with bio-additive lemon essential oil was carried out. The analysis results are compared with the biodiesel standard SNI 7182-2015 to see whether the product/sample approaches the physical properties of biodiesel

Titanium hexacyanoferrate/carbon nanotube composites as the cathode material for aqueous sodium/zinc ion batteries

Aqueous zinc ion batteries (AZIBs), featuring its low cost and environmental protection, are regarded as the promising alternative for traditional energy storage devices acting on clean power generation and electrical vehicles. Prussian blue analogues (PBAs) have received a lot of attention for a potential cathode candidate in AZIBs due to its competence in accommodating various ions with good electrochemical stability. However, conventional PBAs have some inherent problems in Zn ions de-intercalation involving of high discharge potential separation, low structural stability, and high raw material cost. Herein, titanium hexacyanoferrate/carbon nanotube composite (TiHCF-CNT) is synthesized and applied to the cathode materials for aqueous sodium/zinc ion batteries at the first time. The resultant material exhibits not only a high capacity for 134.6 mAh g−1 at 0.05 A g−1, but also excellent cycling stability of 93.7 % capacity retention after 300 cycles at 0.3 A g−1. Na+ in the electrolyte can decrease the resistance of electrolyte and co-insert in the material structure with Zn2+, thus elevate the electrochemical performances remarkably. Moreover, the defects in the structure are identified as Ti vacancies, and these defects can be occupied by Zn2+ reversibly at the charging-discharging process, which lead to a high reversible capacity and cycle stability accordingly.

Recent Advances in Metabolic Engineering for the Biosynthesis of Phosphoenol Pyruvate–Oxaloacetate–Pyruvate-Derived Amino Acids

The phosphoenol pyruvate–oxaloacetate–pyruvate-derived amino acids (POP-AAs) comprise native intermediates in cellular metabolism, within which the phosphoenol pyruvate–oxaloacetate–pyruvate (POP) node is the switch point among the major metabolic pathways existing in most living organisms. POP-AAs have widespread applications in the nutrition, food, and pharmaceutical industries. These amino acids have been predominantly produced in Escherichia coli and Corynebacterium glutamicum through microbial fermentation. With the rapid increase in market requirements, along with the global food shortage situation, the industrial production capacity of these two bacteria has encountered two bottlenecks: low product conversion efficiency and high cost of raw materials. Aiming to push forward the update and upgrade of engineered strains with higher yield and productivity, this paper presents a comprehensive summarization of the fundamental strategy of metabolic engineering techniques around phosphoenol pyruvate–oxaloacetate–pyruvate node for POP-AA production, including L-tryptophan, L-tyrosine, L-phenylalanine, L-valine, L-lysine, L-threonine, and L-isoleucine. Novel heterologous routes and regulation methods regarding the carbon flux redistribution in the POP node and the formation of amino acids should be taken into consideration to improve POP-AA production to approach maximum theoretical values. Furthermore, an outlook for future strategies of low-cost feedstock and energy utilization for developing amino acid overproducers is proposed.

Circular economy approach: Nutrient recovery and economical struvite production from wastewater sources by using modified biochars

The enrichment of phosphorus (P) and nitrogen (N) in aquatic systems can cause eutrophication. Moreover, P rocks may become exhausted in the next 100 years. A slow-release fertilizer called struvite (MgNH4PO4.6H2O) can reduce surface runoff. However, the high cost of raw material or chemicals is a bottleneck in their economical production. Therefore, incinerated sewage sludge ash, food wastewater, and bittern were combined as the sources of P, N, and Mg, respectively. Sawdust biochar was used to enhance the adsorptive recovery of nutrients. First, recovery kinetics was studied by comparing bittern-impregnated biochar (BtB) with the Mg-impregnated biochar (MgB). Subsequently, the synergistic physical and chemical interactions were observed for P and N recovery. Almost complete PO43–P recoveries were achieved within 10 min for both biochars. However, NH4+-N recovery was stable after 2 h, with 26% recovery by MgB and 20% recovery by BtB. Biochars activated with steam (steam-activated biochar) and KOH (KOH-activated biochar) gave superior activities to those of unactivated biochars and activated carbon (AC) nutrient recovery and struvite purity. Moreover, the activated biochars showed a lower risk of surface runoff, similar to that of AC. Therefore, activated biochars can be used as an alternative to AC for economical struvite production from a combination of wastewater sources.

A rapid protocol for synthesis of chitosan nanoparticles with ideal physicochemical features

In this research, an innovative protocol is introduced to address crucial deficiencies in the formulation of chitosan nanoparticles (Cs NPs). While NPs show potential in drug delivery systems (DDSs), their application in the clinic is hindered by various drawbacks, such as toxicity, high material costs, and time-consuming and challenging preparation procedures. Within polymer-based NPs, Cs is a plentiful natural substance derived from the deacetylation of chitin, which can be sourced from the shells of shrimp or crab. Cs NPs can be formulated using the ionic gelation technique, which involves the use of a negatively charged agent, such as tripolyphosphate (TPP), as a crosslinking agent. Even though Cs is a cost-effective and biocompatible material, the formulation of Cs NPs with the correct size and surface electrical charge (zeta potential) presents a persistent challenge. In this study, various techniques were employed to analyze the prepared Cs NPs. The size and surface charge of the NPs were evaluated using dynamic light scattering (DLS). Morphological analysis was conducted using field emission-scanning electron microscopy (FE-SEM). The chemical composition and formation of Cs NPs were investigated using Fourier transform infrared (FTIR). The stability analysis was confirmed through X-ray diffraction (XRD) analysis. Lastly, the biocompatibility of the NPs was assessed through cell cytotoxicity evaluation using the MTT assay. Moreover, here, 11 formulations with different parameters such as reaction pH, Cs:TPP ratio, type of Cs/TPP, and ultrasonication procedure were prepared. Formulation 11 was chosen as the optimized formulation based on its high stability of more than three months, biocompatibility, nanosize of 75.6 ± 18.24 nm, and zeta potential of +26.7 mV. To conclude, the method described here is easy and reproducible and can be used for facile preparation of Cs NPs with desirable physicochemical characteristics and engineering ideal platforms for drug delivery purposes.

Two-dimensional medium-entropy SeSI composite cathodes with cascaded redox reactions for advanced sodium batteries

Na−S/Se/I2 batteries represent a promising rechargeable Na battery system because of high theoretical energy density and low raw material cost. However, the inherent electrical insulation and poor structural stability of S/Se/I2 cathodes result in the unsatisfactory battery performance. Here we develop a new medium-entropy Se-S-I composite cathode via a straight chemical reaction of 2xSe+yI2+CS2=2SexSIy+C, simultaneously consolidating a ternary Se-S-I compound within carbon nanocage, forming a SeSI@C core-shell structure. In the composite, SeSI has a distinctive single crystal structure with homogeneous elemental composition, while carbon shell shows a uniform annular nanoscale that can completely envelop SeSI active mass. The cathode structural design bears high electrical conductivity, fast synergistic activation and excellent structural integrity, accordingly enabling a high capacity with an ultralong cycle life in a representative Na−Se-S-I battery (425.4 mAh g−1 at 10.0 A g−1, 91.6 % retention for 2000 cycles). Notably, a tertiary cascade of Se, S, and I redox has been demonstrated for providing high capacity, and an in-situ grown carbon shell ensures electrical conductivity and structural stability through the entire cathode. This SeSI@C cathode architecture significantly alleviates issues of traditional S/Se/I2-based cathodes, and makes the Na−Se-S-I battery more promising for application.

Flexural and Shear Strengthening of Reinforced-Concrete Beams with Ultra-High-Performance Concrete (UHPC)

Ultra-high-performance concrete (UHPC) is considered to be a promising material for the strengthening of damaged reinforced concrete (RC) members due to its high mechanical strength and low permeability. However, its high material cost, limited code provisions, and scattered material properties limit its wide application. There is a great need to review existing articles and create a database to assist different technical committees for future code provisions on UHPC. This study presents a comprehensive overview focusing on the effect of the UHPC layer on the flexural and shear strengthening of RC beams. From this review, it was evident that (1) different retrofitting configurations have a remarkable effect on the cracking moment compared to the maximum moment in the case of flexural strengthening; (2) the ratios of the shear span and UHPC layer thickness have a notable effect on shear strengthening and the failure mode; and (3) different bonding techniques have insignificant effects on shear strengthening but a positive impact on flexural strengthening. Overall, it can be concluded that three-side strengthening has a higher increment range for flexural (maximum, 81%–120%; cracking, 300%–500%) and shear (maximum, 51%–80%; cracking, 121%–180%) strengthening. From this literature review, an experimental database was established, and different failure modes were identified. Finally, this research highlights current issues with UHPC and recommends some future works.

APPLICATION OF VALUE ENGINEERING IN ARCHITECTURAL WORK ON THE LAHAIROI LATERI CHURCH, AMBON CITY

Effective construction cost control such as saving construction costs will increase the chances of project success and user satisfaction. The biggest component in construction costs is material. High material costs necessitate a review of building functions. Construction savings are made by reviewing the largest cost components in architectural work. Review of material components is carried out using the value engineering method. Value engineering is a method for getting an alternative picture so that the costs incurred are more efficient than the initial planning costs. The application of value engineering to construction projects has a major impact on planning by generating reviews to obtain cost effectiveness. Research was conducted at the Lahairoi Lateri Church Building project located in Ambon City. The aim of this research is to find alternative material substitutes for architectural work and obtain total cost savings by using the concept of value engineering. The use of the value engineering concept is carried out by information phase, analyzing the function of using index function analysis techniques, identifying alternative materials, and evaluating the results of the alternative materials. Research using the value engineering concept on the Lahairoi Lateri Church Building Construction project, Ambon City achieved cost savings of 861,116,841.05 IDR. This amount saves 5.32% of the initial architectural work costs of 16,170,539,500 IDR. These results show that value engineering can eliminate unnecessary costs in church-type building without changing the building function.

Empowering underprivileged students beyond financial aid: Insights from a scholarship program's monitoring and evaluation

PurposeThis paper examines the impact of a scholarship program on underprivileged students, drawing on data from a two-year monitoring and evaluation (M&E) process. The report identifies both enablers and barriers to academic success among scholarship beneficiaries. MethodsData on program impact was collected through interviews with parents, teachers, and school records over two academic years. ResultsFinancial aid emerged as a crucial enabler, with scholarships allowing students to focus on their studies by alleviating pressure around basic necessities. However, the research also revealed the importance of a holistic support system. Beyond tuition, the high cost of essential learning materials, including stationery, and subject-specific resources, can create a significant barrier. The study also highlighted the importance of student well-being. Health concerns, limited access to nutritious food, and even unaddressed mental health issues can all negatively impact attendance and focus. Furthermore, a gender gap emerged, with girls facing additional challenges related to social pressures to prioritize chores and the cost of menstrual hygiene products. ConclusionThis study highlights the importance of holistic scholarship programs that extend beyond tuition coverage. To maximize impact, policymakers and funders should prioritize initiatives that address the multifaceted needs of underprivileged students.

Amoeba‐Inspired Self‐Healing Electronic Slime for Adaptable, Durable Epidermal Wearable Electronics

AbstractEpidermal electronics has garnered significant research attention due to its promising applications in wearable human‐machine interfaces and intelligent healthcare sensing. However, their widespread use faces challenges due to complex manufacturing processes, high material costs, inadaptability to different skin surfaces, and inadequate reusability. Herein, inspired by the biological reshapability and environmental adaptability of amoeba, an ultra‐deformable (≈2600% strain), bioadhesive (adhesive strength ≈3 kPa), strong self‐healing (fastest recovery time ≈1s, maximum wound distance ≈5 mm), and electromechanical‐durable wearable electronic slime (E‐slime) is proposed, which can instantaneously form on‐skin electronics in situ to detect body motion and physiological signals. E‐slime demonstrates desired sensing performance with high sensitivity (gauge factor 2.95), wide sensing range (up to 400% strain), and low detection limit (≈1% strain), which can seamlessly adhere to the skin and can be easily reused multiple times (≈100 cycles usage). E‐slime also enables on‐the‐fly deployment of motion monitoring tasks at various body locations, showcasing its versatility and reliability for body motion recognition and personal health monitoring. This study holds potential for next‐generation green electronics, motion sensing devices, and wearable human‐machine interfaces, ultimately helping to ensure healthy lives and promote well‐being.

Exploring the feasibility of utilizing high plastic clays as an alternative material to bentonite clay in the production of ceramic tile: Advancing towards efficient life cycle cost

The environmental challenges and high cost of raw materials (i.e., bentonite clays) for the production of ceramic tiles raise concerns for the ceramic industry to look for alternative materials. Therefore, the current research aimed at exploring the possibility of using high plastic clays as a replacement for Bentonite clay in the manufacturing of ceramic tiles. Two different types of high plastic clay in different proportions (i.e. 0–5 %) were used in the preparation of ceramic tiles. A comprehensive material characterization, shrinkage, visual index, flexural strength, water absorption, and microstructural investigation was carried out. The results revealed that the incorporation of plastic clays RC1 from 1 % to 5 % showed a decrease in the flexural strength of ceramic tiles as compared to that of ceramic tiles with bentonite clay. The water absorption of ceramic tiles using RC1 increased with the incorporation of high plastic clays for high plastic clays. However, specimens with all replacements of bentonite clay with high plastic clays showed flexural strength greater than the minimum specified limit of ISO 10545-4. Moreover, it was observed that the replacement of bentonite clay with high plastic clays exhibited higher shrinkage. Further, the visual index of all the specimens did not show any sign of the presence of black core in the ceramic tiles incorporating high plastic clays. The life cycle assessment (LCA) was carried out for the possible utilization of high plastic clays in place of bentonite clay to produce ceramic tiles. The results showed that less than 5 % high plastic clay can effectively be used for manufacturing ceramic tiles leading to economical and sustainable construction products. Hence, it can be concluded that the high plastic clays can be utilized as an alternative to bentonite clay material for manufacturing sustainable ceramic tile leading to sustainable finishes in construction.

Work Function Tuning of Carbon Electrode to Boost the Charge Extraction in Hole Transport Layer-Free Perovskite Solar Cells.

Perovskite solar cell (PSC) is a promising photovoltaic technology that achieves over 26% power conversion efficiency (PCE). However, the high materials costs, complicated fabrication process, as well as poor long-term stability, are stumbling blocks for the commercialization of the PSCs in normal structures. The hole transport layer (HTL)-free carbon-based PSCs (C-PSCs) are expected to overcome these challenges. However, C-PSCs have suffered from relatively low PCE due to severe energy loss at the perovskite/carbon interface. Herein, the study proposes to boost the hole extraction capability of carbon electrode by incorporating functional manganese (II III) oxide (Mn3O4). It is found that the work function (WF)of the carbon electrode can be finely tuned with different amounts of Mn3O4 addition, thus the interfacial charge transfer efficiency can be maximized. Besides, the mechanical properties of carbon electrode can also be strengthened. Finally, a PCE of 19.03% is achieved. Moreover, the device retains 90% of its initial PCE after 2000 h of storage. This study offers a feasible strategy for fabricating efficient paintable HTL-free C-PSCs.

Effect of difference in microstructure of rare refractory metal silicate doping matrix on oxidation behavior and mechanism of C/SiC composites

Doping refractory metal silicates into the matrix of C/SiC composites is an effective means to improve their oxidation resistance. Previous studies have demonstrated that doping HfSiO4 matrix availably enhanced the oxidation resistance of C/SiC composites, but the high raw material cost of HfSiO4 limits its widespread application. This paper attempts to introduce ZrSiO4 matrix, which has lower raw material cost and similar properties to HfSiO4, into C/SiC matrix through the same process. To clarify whether the microstructure of the refractory metal silicate doped matrix significantly impacts the oxidation behavior of C/SiC composites, the preparation temperature of ZrSiO4 was increased to 1100 °C. The densification effect, oxidation behavior, and related mechanisms of C/SiC composites doped with ZrSiO4 matrix were investigated and compared in detail with the previously studied C/SiC composites doped with HfSiO4 matrix. Results show that the oxidation resistance behavior of C/SiC composites is relatively sensitive to the microstructure of the refractory metal silicate-doped matrix. At lower preparation temperatures of refractory metal silicates, the particle size of the composite matrix is significantly refined, which is conducive to improving the matrix densification degree of the composites and protecting more carbon fibers from erosion by the oxidizing environment, thus achieving a better oxidation resistance modification effect.

Efficient preparation of metallic titanium from lower valence titanium chloride slurry by electrochemical reduction in molten salts

Short extraction of metallic titanium by the electrochemical reduction process in molten salt has attracted increasing interest due to its many advantages. The electrolysis of high-purity titanium to produce lower valence titanium chlorides has so far been industrialized as balancing agents but large-scale production is still challenging due to the high cost of raw materials and easy deterioration. Herein, metallic titanium was extracted from lower valence titanium chlorides (LTCs) slurries by electrochemical reduction in molten salts. The results of LTC slurries at 260 ºC for 48 h revealed the formation of red-violet α- and γ- TiCl3 with an Al content below 0.09 wt%, which gradually reduced to form metallic titanium in molten salt electrolytes. Porous metallic Ti powders were obtained from TiCl3 by electrochemical reduction in KCl-LiCl-MgCl2 molten salt at 400 °C. The reaction at the anode area was accompanied by TiCl4 gas overflow, and continuous electrolysis of metallic titanium was achieved by supplementing the consumed TiCl3. Overall, the proposed electrolysis process looks promising for large-scale applications due to its simple electrolysis equipment, relatively stable electrolyte components, and good product quality, thereby worth further future investigation.

Flexible Janus Black Silicon Photothermal Conversion Membranes for Highly Efficient Solar-Driven Interfacial Water Purification.

Photothermal conversion materials are critical in the development of solar-driven interfacial evaporation techniques; however, achieving a high energy conversion efficiency remains challenging owing to the high cost and instability of light-absorbing materials, in addition to the difficulties of simultaneously improving light absorption while suppressing heat loss. A black silicon (Si) powder with a porous structure was prepared by chemical etching of a low-cost commercial micron-sized Al-Si alloy, and a flexible Janus black Si photothermal conversion membrane was constructed. The partially broken spherical particles and porous structure obtained after etching enhanced the refraction of light from the Si powder, imparting the prepared membrane with an average light absorption rate of 95.95% over the solar spectrum. Evaporation from the membrane increased the intermediate water content and reduced the equivalent evaporation enthalpy. The thermal conduction loss was inhibited through a one-dimensional water transport structure, and the membrane achieved a water evaporation rate of 2.17 kg m-2 h-1 and a photothermal efficiency of 94.95% under 1 sun illumination. Benefiting from the broadband absorption and high photothermal efficiency of black Si powder, surface modification of hydrophobic polydimethylsiloxane, and directional salt-out structure design, the evaporation rate of the Janus black Si membrane-based system in a 10% NaCl solution was maintained >2.10 kg m-2 h-1 after 7 days of continuous evaporation cycles. The removal rate of metal ions from simulated seawater and from practical wastewater containing complex heavy metals reached >99.9%, indicating the promising potential of black Si membrane for application in solar-driven interfacial water purification.

An approach to estimate the low cycle fatigue probabilistic curves of PBF-LB/M 316L steel from small size datasets using the remora optimization algorithm

The significant dispersion in fatigue properties is a prevalent attribute observed in metals manufactured by the Additive Manufacturing (AM). To ascertain the safety of components subjected to low cycle fatigue (LCF) loadings at a temperature of 550 °C, it is necessary to carry out a fatigue reliability assessment of AM metals. Nevertheless, the number of LCF life tests is limited owing to time-consuming nature of test and high total production cost of AM materials. Such a small size dataset cannot satisfy the criteria of the traditional reliability assessment method. This work aims to develop a novel method to evaluate the LCF reliability of 316L stainless steel manufactured by laser-based powder bed fusion of metals (PBF-LB/M) technology. Firstly, the Weibull model is coupled with the Coffin-Manson-Basquin relationship in order to characterize the dispersion of life data points at various strain levels. Secondly, reliability results from a small size dataset show a maximum relative error in fatigue life of less than 25 %, which is similar to results from a large size dataset and the traditional method using fatigue data from public sources. Among this step, the remora optimization algorithm is firstly applied to calculate the characteristic parameters of newly-proposed method. Thirdly, the LCF reliability of PBF-LB/M 316L based on the small size dataset is evaluated. The N95% is equivalent to 44 % of N50%. Finally, the PBF-LB/M 316L is compared with traditional 316L considering the reliability. The LCF properties of PBF-LB/M 316L is similar to the traditional 316L at 50 % reliability, however it’s slightly worse at 95 % reliability.

Superplastic deformation behavior of low Al–added medium Mn steels with and without Ti and Mo elements

Fe-Mn-Al-C medium Mn steels were found to reveal extraordinary superplasticity and have significant potential for forming the complex structural parts due to high strength, excellent ductility and material cost. In present study, the effect of tensile deformation temperature on the superplastic deformation behavior of a cold-rolled low Al-added medium Mn steel was studied. A maximum tensile elongation of approximately 1170% was obtained at 745 °C and 10−2 s−1, which is to our best knowledge the highest low-temperature-high-strain-rate superplasticity in medium Mn steels. Also, the role mechanism of microalloying elements such as Ti and Mo was revealed to further enhance the strength level of superplastic medium Mn steels. In view of the representative microstructural features, such as equiaxed grains, random texture, and sluggish grain growth, grain boundary sliding is thought to be the dominative mechanism during the high-strain-rate superplastic deformation.

A urea-based approach to synthesize single atom iron catalysts for catalyzing peroxymonosulfate to degrade antibiotics

Understanding the role and catalytic mechanism of single atomic catalysts (SACs) in activating peroxymonosulfate (PMS) and subsequently eliminating antibiotics in environmental water is crucial for designing more efficient catalysts. Despite C-N-metal SACs exhibiting excellent performance, their application is constrained by the intricate N-doped pretreatment process and the high cost of carrier materials. To handle these challenges effectively, a new approach, by using molten urea as both solvent and nitrogen source and polyethylene glycol as carbon source, was employed to synthesize the u-Fex-N-C (x = 1, 2, 3) catalysts. In which, u-Fe1-N-C had achieved an impressive 92 % degradation ratio for oxytetracycline (OTC) and remains unaffected by pH in the range of 3–11. It further exhibited catalytic degradation activity towards a broad spectrum of environmental pollutants, including sulfamethoxazole (SMZ), naproxen (NPX), ofloxacin (OFL), rhodamine B (RhB), and bisphenol A (BPA), and the degradation efficiencies reached 67 %, 83 %, 77 %, 99 %, and 93 %, respectively. According to a series of the characterization, the prepared u-Fe1-N-C possessed a unique FeN4 structure. Electron paramagnetic resonance (EPR) and radical quenching experiments proved that 1O2 and Fe (Ⅳ) played a key role in the current reaction system. In-situ Raman and electrically coupled oxidation systems also proved that the non-radical degradation pathway involving electron transfer in the u-Fe1-N-C/PMS system was the primary way for activating PMS. The degradation efficiency of OTC from real water samples still reached 84 %. This work provides a simple and cost-effective strategy for synthesizing SACs, offering promising applied prospects in the field of water treatment and environmental remediation.