Material Issues Research Articles

Understanding Preschool Educators' Writing Knowledge: Insights from the Early Writing Knowledge Assessment

AbstractTeachers' knowledge impacts their practices in classrooms. While considerable research has sought to understand teachers' broad emergent literacy knowledge, less is known about the specific knowledge teachers hold regarding early writing. The present study engaged 66 diverse early childhood teachers in five Head Start programs across two states to examine teachers' knowledge for early writing, bringing specificity to our understanding of teachers' knowledge of writing skills and development. To overcome issues of current elicitation materials which employ researcher generated questioning and decontextualized testing formats, we utilized an innovative instrument (The Early Writing Knowledge Assessment: EWKA) to elicit teachers' knowledge and beliefs from three authentic, contextualized child writing samples reflecting distinct, developmental writing skills. Teachers reflected on each sample and responses were coded using a two‐step process and an a priori set of codes derived from established early writing theories. Results indicated that generally, teachers' early writing knowledge aligned with research‐based conceptualizations, however, wide variation existed in the language used. Patterns existed in the components and subcomponents emphasized depending on the developmental skills demonstrated in the sample. Study findings highlight the wide variability, including inaccuracies, of teachers' early writing knowledge and the inconsistent language used to describe writing development used in the field, both of which have implications for research and practice. Implications for the field, including the potential use of the EWKA to better understand the workforce and for use in professional learning are further discussed.

Review of The Impact Of Hydrogen-Containing Fuels On Gas Turbine Hot-Section Materials

Abstract In an effort to achieve worldwide decarbonization goals, a range of low-carbon fuels is being proposed for use in power-generation gas turbines. Two promising fuels are hydrogen and ammonia, which do not produce any CO2 upon combustion. While the use cases of these fuels differ, each has the potential to reduce the carbon intensity of power generation as compared to the current use of natural gas and fuel oil. Many studies have considered the impact that these fuels will have on combustion stability and emissions, as well as other practical considerations like balance of plant. However, potential challenges for the material systems in these engines, particularly high-temperature metal alloys and coatings, have not been sufficiently considered in preparation for the introduction of these fuels. The goal of this paper is to provide a review of the potential material issues associated with implementation of these hydrogen-containing fuels, with a focus on materials in the hot section of existing power-generation gas turbines. To date, relatively little research has considered these material issues at realistic gas turbine conditions, resulting in a need for new research. This paper provides a review of the literature, first-order analyses of the magnitude of potential issues, and avenues for research to facilitate the safe and reliable introduction of these fuels in power-generation gas turbines.

Fully printed zero-static power MoS2 switch coded reconfigurable graphene metasurface for RF/microwave electromagnetic wave manipulation and control

Reduction of power consumption is the key target for modern electronic devices. To this end, a lot of attention is paid to zero-static power switches, being able to change their state between highly resistive and highly conductive and remain in this state even in the absence of external voltage. Still, the implementation of such switches is slow because of compatibility issues of new materials with CMOS technology. At the same time, printable technology enables low-cost processes at ambient temperature and integration of devices onto flexible substrates. Here we demonstrate that printed Ag/MoS2/Ag heterostructures can be used as zero-static power switches in radiofrequency/microwave spectrum and fully-integrated reconfigurable metasurfaces. Combined with graphene, our printed platform enables reconfigurable metasurface for electromagnetic wave manipulation and control for wireless communications, sensing, and holography. In addition, it is also demonstrated that the localised MoS2 phase change may have promoted Ag diffusion in forming conductive filaments.

Flame-induced performance enhancement of MXene-based nanocomposite sponge for infrared stealth and strain sensing

Assembling MXene nanofillers on a macroscopic carrier via the non-covalent bonding forces is one of the most efficient paths for preparing the MXene-based nanocomposites with multi functions and hierarchical structure. However, the frequently-used substrates, such as cotton fabric, synthetic textile, and polymer sponge are highly flammable, severely restricting the practical applications in some highly integrated scenarios. Herein, we report a facile design strategy that enables us to readily achieve the flame retardant MXene-based nanocomposites for highly efficient infrared stealth and strain sensing even when used in high-temperature environments. In particular, a phosphorus-nitrogen rich compound (HPTCP) was intercalated into the laminates of Ti3C2Tx-MXene to construct a hybrid flame retardant that was coated on the skeletons of melamine sponge by repeated dip-coating procedures. As a result of the synergistic effect among multicomponent, the Ti3C2Tx-HPTCP coated sponge displays excellent structural stability in real fire. In this case, flame treatment was adopted to create micro-/nano-scale cracks in the coated sponge and skeletons, significantly enhancing the sensitivity (∼0.20 kPa−1) and shortening the response time (69 ms) to strain. The burned sponge sensor can be employed for monitoring various human motions, from tiny throat vibrations and facial expressions to large-scale finger and knee bending. Besides, the burned sample still maintains the superior infrared stealth performance with a wide stealth temperature range, a large reduction in radiation temperature of 154 °C for the object temperature of 300 °C, and long-term working stability at high temperatures. Given the simple fabrication process, multilevel structural design, and stable performance, this work provides a promising strategy for addressing the flammability issue of template-based composite materials

Pitch-derived C coated three-dimensional CNTs/reduced graphene oxide microsphere encapsulating Si nanoparticles as anodes for lithium-ion batteries

This study presents an innovative strategy for synthesizing a sophisticated three-dimensional conductive framework that contains well-dispersed silicon nanoparticles. This framework features silicon nanoparticles encapsulated by a composite of one-dimensional carbon nanotubes (CNTs), two-dimensional reduced graphene oxide (rGO), and amorphous carbon, all of which are further coated with a pitch-derived carbon (PDC) layer. This unique nanostructured anode was prepared from a one-pot spray drying process, heat-treatment and subsequent pitch-derived carbon coating. Combining 1D CNTs and 2D rGO nanosheets creates a 3D conductive network that can facilitate the electrochemical reaction kinetics. Furthermore, pitch-derived carbon coating at the interior and on the surface densified the electrode, ensuring both lithium-ion and electron transport and enhancing the Coulombic efficiency. Therefore, the composite plays the role of an effective mixed ionic and electronic conductor (MIEC), which can highly enhance the electrochemical performance of Si-based anode. Also, the volume expansion issues of silicon materials could be resolved by compositing with 3D conductive carbon matrix and reinforcing the structural robustness by coating with PDC layer, which could effectively alleviate the stress occurring from repetitive cycling. When used as the anode in lithium-ion batteries, the microspheres exhibited exceptional initial discharge/charge capacities of 3814/2791 mA h g–1 at 0.1 A g−1 with high Coulombic efficiency of 73.2 %, and demonstrated highly stable cycle performance, delivering a discharge capacity of 947 mA h g−1 after 350 cycles at a current density of 1.0 A g−1.

MONITORING MUSICAL DEVELOPMENTOF CHILDREN OF THE THIRD YEAR OF LIFE,TAKING INTO ACCOUNT HOLISTIC THINKING

The article discusses the concept of functional asymmetry of the child’s cerebral hemispheres and the universal developmental paradigm. The universal developmental paradigm means that the characteristic of the world in which we exist is its duality, its division into right and left, light and dark, good and evil... It is thinking, as a function of the human mind, that can be considered the essence of man - a fundamentally intelligent being, and therefore thinking, since thinking is a system-forming factor of man as a living system, and at the same time a necessary and sufficient factor of his being as a rational being, as a species of Homo sapiens. Therefore, the main developmental goal of education should be considered the development of thinking in pupils. Preschool children's brains are used to remembering everything as it is - in a variety of colors, smells, sounds, and other factors. During reproduction, an image-model is created in the right hemisphere, and a verbal definition corresponding to the image is created in the left hemisphere. As a result, perception is not erased, it gives rise to brilliant poems, books, paintings, discoveries. This is unlimited and natural for him. During learning, in most cases, either the left or the right hemisphere of the brain is loaded, while the opposite remains unused. Experimentally, using K. Pearson’s criterion, it was confirmed that the musical development of a child of the third year of life will be more effective and qualitative if the holistic thinking of the two hemispheres of the child's brain is involved. Holistic thinking is the combined work of the two cerebral hemispheres, relying on all channels of information perception. Of course, the tasks of developing preschool children’s personality will be successfully solved if music lessons include consideration of the main issues of factual material. In this case, the music teacher varies the methods of study and forms of work. We propose conditions for individual and personal development of the child, namely, within the framework of the program, thematic planning, conducting classes, games, matinees, etc. the music teacher should have didactic material that changes the type and form of presentation of educational material, and the child has the freedom to choose the task (the same task should provide the possibility of its implementation through an image, word, scheme, modelling, musical accompaniment, movement, etc.), that is, to promote the integration of the right and left types of being in learning and development. Activities that involve two hemispheres of the preschoolers' brain simultaneously will be more effective.

СТАТИСТИЧНІ МЕТОДИ У ПРОВЕДЕННІ ПЕДАГОГІЧНИХ ДОСЛІДЖЕНЬ (ПРИКЛАДНИЙ АСПЕКТ)

The article discusses the concept of functional asymmetry of the child’s cerebral hemispheres and the universal developmental paradigm. The universal developmental paradigm means that the characteristic of the world in which we exist is its duality, its division into right and left, light and dark, good and evil. It is thinking, as a function of the human mind, that can be considered the essence of man - a fundamentally intelligent being, and therefore thinking, since thinking is a system-forming factor of man as a living system, and at the same time a necessary and sufficient factor of his being as a rational being, as a species of Homo sapiens. Therefore, the main developmental goal of education should be considered the development of thinking in pupils. Preschool children's brains are used to remembering everything as it is - in a variety of colours, smells, sounds, and other factors. During reproduction, an image-model is created in the right hemisphere, and a verbal definition corresponding to the image is created in the left hemisphere. As a result, perception is not erased, it gives rise to brilliant poems, books, paintings, discoveries. This is unlimited and natural for him. During learning, in most cases, either the left or the right hemisphere of the brain is loaded, while the opposite remains unused. Experimentally, using K. Pearson’s criterion, it was confirmed that the musical development of a child of the third year of life will be more effective and qualitative if the holistic thinking of the two hemispheres of the child's brain is involved. Holistic thinking is the combined work of the two cerebral hemispheres, relying on all channels of information perception. Of course, the tasks of developing preschool children’s personality will be successfully solved if music lessons include consideration of the main issues of factual material. In this case, the music teacher varies the methods of study and forms of work. We propose conditions for individual and personal development of the child, namely, within the framework of the programme, thematic planning, conducting classes, games, matinees, etc. the music teacher should have didactic material that changes the type and form of presentation of educational material, and the child has the freedom to choose the task (the same task should provide the possibility of its implementation through an image, word, scheme, modelling, musical accompaniment, movement, etc.), that is, to promote the integration of the right and left types of being in learning and development. Activities that involve two hemispheres of the preschoolers’ brain simultaneously will be more effective.

Beyond formal politics: the epistemic facet of business power

Abstract This article introduces “epistemic business power” as a distinct facet of corporate influence. Epistemic business power refers to the strategic communication of firms to influence the perceptions and beliefs of policymakers, experts, media, and the public regarding which issues, goals, norms, methods, and instruments to be politically considered. Rather than influencing decision-making and policy formulation directly, this form of power enables firms to intermediate the anticipatory dynamics of structural forms of business power and shape issue salience as well as the definition and recognition of topics as political problems. The article explores the scope conditions of epistemic business power, detailing the interaction of material aspects, corporate communication and issue salience dynamics. Based on quantitative and qualitative content as well as reception analyses, ownership data and interviews, a case study of the world’s largest asset manager BlackRock illustrates how today’s finance capital can use epistemic channels with regard to fundamental questions about the role of state capacity and private enterprise in capitalist democracies. By foregrounding the political nature of corporate public relations, the conceptual endeavor and its empirical illustration contribute to a deeper understanding of corporate power and its multifaceted role in shaping politics in capitalist democracies.

Optical performance and luminescence properties of Dy3+-doped LaMgB5O10 phosphors

Despite significant advancements in borate-based phosphors, improving luminescent efficiency and thermal stability, particularly at high temperatures, remains a persistent challenge. In this study, Dy3+-doped LaMgB5O10 (LMBO) phosphors were synthesized and characterized for their photoluminescent properties to address these issues. Under 344 nm excitation, the Dy3+-activated LMBO phosphors exhibited strong luminescence with characteristic peaks at 482 nm (blue), 578 nm (yellow), and 663 nm (red), corresponding to specific Dy3+ transitions. Optimal luminescence was achieved at a doping level of 2 wt% Dy3+, beyond which quenching effects reduced emission intensity. The critical quenching distance (Rc) was estimated at 24.66 Å, indicating predominant non-radiative energy transfer. Moreover, thermal quenching was reduced, with the activation energy for thermal quenching determined to be 0.1975 eV, demonstrating that the material can maintain reasonable luminescence efficiency at elevated temperatures. Time-resolved photoluminescence spectroscopy revealed multi-exponential decay behavior, indicating the presence of multiple decay processes. The average luminescence lifetimes were calculated as 632 µs for the 2 wt% Dy3+ sample and 539 µs for the 3 wt% Dy3+ sample, with a clear concentration quenching effect observed at higher dopant levels. Colorimetric analysis in the CIE 1931 color space revealed a shift toward yellow with increasing Dy3+ concentration, achieving a correlated color temperature (CCT) of 6595 K at 2 wt% Dy3+. This shift supports the material’s potential for photonic and lighting applications. These findings highlight a significant advancement in addressing the thermal stability issue in phosphor materials, making Dy3+-doped LMBO phosphors promising candidates for advanced photonic technologies.

Charge Dynamics and Defect States under “Spot‐Light”: Spectroscopic Insights into Halide Perovskite Solar Cells

Halide perovskite solar cells (PSCs) have shown remarkable power conversion efficiencies. However, the inherent defect issues of perovskite materials still limit their performance and long‐term stability, resulting in lifespans far from commercial standards. With their noninvasive approach to probing the electronic and vibrational properties of materials, spectroscopic techniques have become crucial tools for uncovering and understanding defect states and complex charge carrier dynamics in halide perovskites. This review explores the application of various advanced spectroscopic techniques in PSCs to elucidate the complex behaviors of charge carriers within PSCs. These techniques reveal detailed temporal and spatial distributions of charge carriers, enabling precise analysis of defect impacts and interfacial charge transfer processes. By integrating spectroscopic data, it is possible to more accurately identify and mitigate defect‐induced nonradiative recombination and charge transfer, thereby enhancing the stability and efficiency of PSCs. This comprehensive spectroscopic understanding is crucial for developing innovative technologies to accelerate the commercial viability of PSCs.

Digital Twin Used in Real-Time Monitoring of Operations Performed on CNC Technological Equipment

This article presents the development and implementation of a real-time monitoring solution designed for CNC machines, specifically applied to 150 industrial printing machines, leveraging Digital Twin (DT) technology. The system integrates an SQL database with Android and .NET interfaces, ensuring seamless data synchronization across all machines and optimizing production processes. The real-time monitoring enables immediate reflection of operational changes, enhancing predictive maintenance and reducing machine downtime. A notable feature of the system is its 1 s average data synchronization rate per machine, managing 150 resources distributed over a 10,000 mp area. This fast synchronization improves workflow coordination, reducing production time by approximately 10%, and minimizing operator delays caused by material issues, machine malfunctions, or product defects. The integration of advanced analytics further supports real-time decision-making, predictive maintenance, and performance optimization, aligning the solution with the objectives of Industry 4.0 and Industry 5.0 initiatives. This version reflects the specific results of the research, including the 1 s synchronization rate, the 10% reduction in production time, and the scalability of the system for 150 resources.

Resonant cavity structural design of carbon-based intrinsic metamaterial absorbers for broadening the effective absorption bandwidth

The effective absorption bandwidth (EAB) of absorptive materials has always been a bottleneck limiting their applications. Particularly, the combination of macroscopic structural design and the loss functions at the microscopic level of materials provides an efficient solution to this issue. Herein, a novel approach was proposed, integrating macroscopic structural design with microscopic loss functions to broaden the effective absorption bandwidth (EAB) through designing an intrinsic metamaterial absorber composed of a uniform blend of carbon-based absorbing materials and polydimethylsiloxane. A key innovation lies in the dual cubic resonant cavity design, where the multiple dimensions of the resonant cavities enable the absorber to achieve effective impedance matching across a wide frequency range. Additionally, the generation of a bottom ring current induces a magnetic field, which enhances the metamaterial absorber’s capability for further attenuation of electromagnetic wave energy. These innovative designs enable traditional carbon-based absorbing materials to achieve exceptional absorption performance, with the EAB being 2.37 times that of the skin structure, addressing the narrow EAB issue of traditional carbon-based absorptive materials. Experimental results demonstrate that the prepared samples achieve an absorption rate of 90 % for electromagnetic waves in the frequency range of 5.74 to 18 GHz under normal incidence, consistent with the simulation results. This absorber boasts advantages of broadband, with an equivalent thickness of only 2.94 mm. Its structure is easy to manufacture, demonstrating certain potential applications, and providing valuable insights for the work of other researchers.

Recent Advances of Carbon Capture in Metal-Organic Frameworks: A Comprehensive Review.

The excessive emission of greenhouse gases, which leads to global warming and alarms the world, has triggered a global campaign for carbon neutrality. Carbon capture and sequestration (CCS) technology has aroused wide research interest as a versatile emission mitigation technology. Metal-organic frameworks (MOFs), as a new class of high-performance adsorbents, hold great potential for CO2 capture from large point sources and ambient air due to their ultra-high specific surface area as well as pore structure. In recent years, MOFs have made great progress in the field of CO2 capture and separation, and have published a number of important results, which have greatly promoted the development of MOF materials for practical carbon capture applications. This review summarizes the most recent advanced research on MOF materials for carbon capture in various application scenarios over the past six years. The strategies for enhancing CO2 selective adsorption and separation of MOFs are described in detail, along with the development of MOF-based composites. Moreover, this review also systematically summarizes the highly concerned issues of MOF materials in practical applications of carbon capture. Finally, future research on CO2 capture by MOF materials is prospected.

Multi-criteria analysis of the improvement interventions related to the Superbonus 110%: efficiency, renewables

Abstract The 2050 long-term strategy of the European Union contains an analysis of the actions that need to be taken for the transition to a zero GHG emission economy and to to build a better future for all by 2050. The outlined scenarios envisage ambitious objectives in terms of the energy efficient building improvements, the use of RES and the reduction of climate-changing emission. Following this European vision, EU Member States have developed national long-term strategies and focusing on the building sector, in Italy the Recovery and Resilience Plan is providing financing and national and European investment is expected to enable the renovation of more than 100,000 buildings, with a total upgraded area of more than 36 million square metres. The expected energy saving is about 191 Ktoe/year with a reduction in greenhouse gas emissions of about 667 Kton CO2/year. At the end of 2023, the energy requalification of buildings reached about 12 million square metres. By 31 December 2025, the objective is to ensure the energy requalification of buildings for at least 32 million square metres. The proposed research aims to investigate the effects of the renovation activities related to the Superbonus 110% through a multi-criteria analysis, taking into account the beneficial effects consisting of the energy efficiency improvement. The research has been conducted starting from a database of 1,545 dwellings on the territory of Italy, using a data collection questionnaire to estimate the energy consumption of a dwelling, with an in-house developed calculation code based on a simplified dynamic simulation. The database has been set to satisfy different purposes: to characterize the energy uses of residential utilities and identify flexible loads; to estimate the effects of energy upgrading interventions; to analyse the transformation potential of residential buildings with the introduction of an integrated PV-Heat Pump-Thermal Storage system; to evaluate the best energy upgrading proposal based on the climate zone and building location; to evaluate the cost of energy upgrading interventions. The proposed activity aims to complement the studies carried out by projecting the existing situation into more scenarios congruent with the national and European context; the envisioned scenario interprets the need to increase the building stock efficiency and integrate more renewable energy resources into energy systems. In light of the estimates produced and the results achieved, the research aims to emphasize the reuse of building materials issue, looking at circular reuse, offering a different and broader assessment of interventions aimed at the construction sector and, more specifically, the residential sector.

Hollow N doped carbon/SiCN hierarchical structures for thermostable electromagnetic absorptions

Electromagnetic absorption materials present widespread application prospects. The thermal oxidative aging issues for electromagnetic absorption materials have received little attention. In this paper, N-doped carbon tubes, and the SiCN ceramics are combined to realize thermostable electromagnetic absorptions. The hierarchical structures show significantly enhanced broadband electromagnetic absorption with an optimal RL of -53.61 dB at 14 GHz under a thickness of 2 mm. The effective electromagnetic absorption bandwidth reaches 5.53 GHz, and the coverage range is 11.88–17.41 GHz. More importantly, after 1 h calcination at 300 °C, the optimum RL of NCT/SiCN-1 h is still -45.67 dB under the thickness of 2.5 mm. The effective electromagnetic absorption bandwidth increases to 5.95 GHz, and the coverage range is 10.69–16.64 GHz. Our work proves the possibility for improving the thermostable electromagnetic absorptions of carbon materials, and provides referencing ways for the design of thermostable electromagnetic absorption materials.

Promoting Layered Oxide Cathodes Based on Structural Reconstruction for Sodium‐Ion Batteries: Reversible Phase Transition, Stable Interface Regulation, and Multifunctional Intergrowth Structure

AbstractLayered transition‐metal oxides (NaxTMO2) are one of the most promising cathode materials for sodium‐ion batteries due to their high theoretical specific capacities, good conductivity, and environmental friendliness. However, several key scientific issues of NaxTMO2 cathode materials still persist in practical applications: i) complex phase transitions during the charge/discharge process owing to the slip of the transition‐metal layer; ii) the tendency for the interface to react with the electrolyte, resulting in structure degradation, and iii) reactions between active materials and H2O as well as CO2 on exposure to air in the environment to form alkaline substances on the surface. To understand electrochemical storage mechanisms and solve these problems, several modification strategies of NaxTMO2 have been reported recently, including bulk doping, concentration gradient structure design, interface regulation, and intergrowth structure construction. This review focuses on reversible phase transitions, stable interface regulation, and multifunctional intergrowth structure of the NaxTMO2 material from the inside to the outside. The future research directions for NaxTMO2 are also analyzed, providing guidance for the development of commercial layered oxides for next‐generation energy storage systems.

Garbage prediction using regression analysis for municipal corporations of Indian cities

AbstractGarbage management is exceptionally critical and poses enormous environmental challenges. It has always been a vital issue in municipal corporations. However, municipal agencies have developed and used garbage management systems. Garbage forecasting still plays a crucial role in the management system and helps improve or create a garbage management system. This research examines the information from 212 cities to suggest a helpful regression model for garbage forecasting and control. To establish a connection between the variables, the descriptive study employs statistical techniques to learn about the composition of data collected from municipal corporations and conduct correlation analysis. Population and garbage depend highly on one another, as evidenced by their correlation coefficient of 0.922,144. The primary research is used to build an alternate hypothesis that shows the chosen variables are highly dependent on one another. The dataset is scaled and divided into a training and testing 80:20 ratio during the pre‐processing data phase. This research aims to do a regression analysis with daily garbage production, urban area, and population as independent variables. This research initiates a variety of regression models, including multiple linear regression (MLR), artificial neural network (ANN), decision tree regression (DTR), and random forest regression (RFR). The MLR model's R2 value of 0.85 indicates that it has the potential to accurately forecast daily garbage production based on just two independent variables and a single dependent variable. Random Forest Regression (RFR) with (MSE: 100,078.749 & MAE: 182.212) shows that it has the lowest MSE among all the models, which provides the most accurate predictions on average and the fit values of 8.85 and 316.23 obtained from the error distribution with a bin value 25. The estimated results from each model are compared to the test data values on line graphs and Taylor plots. The mean square error and the mean absolute error in the analysis and the Taylor plot show that the RFR model is best suited for predicting daily garbage production in a city. This research, therefore, provides a Random Forest model that is optimal for such challenges and is recommended for this class of problem.

Experimental study on the utilization of Fly ash solid waste in tunnel shotcrete materials

AbstractFly ash has emerged as a prominent solid waste in China, leading to various environmental concerns and posing a threat to the health of living organisms, including humans. To enhance the industrial applicability of this waste material, a novel approach has been proposed wherein sand is replaced with fly ash as the primary raw material for wall grouting of coal mine roadways. To address the issue of low compressive strength and to improve the properties of fly ash shotcrete materials, a method employing an alkali activator to stimulate the chemical activity of fly ash has been put forward. The long‐term effectiveness of the shotcrete material has been evaluated using compressive strength testing and scanning electron microscopy testing methods. The impact of replacing sand with fly ash on the compressive strength of shotcrete and the activation effect of sodium sulfate (Na2SO4), NaOH, and Na2SiO3 on fly ash shotcrete have been studied. The results indicate that the compressive strength of fly ash shotcrete shows optimal improvement when the content of Na2SO4 is 3%. The ideal ratio of cement to fly ash is 1:3. Therefore, incorporating an appropriate amount of alkaline activator could effectively address the compressive strength issues of fly ash shotcrete materials.

ESG관점의 세라믹 폐자재 설계 재활용 전략에 관한 연구

The issue of ceramic waste materials is not merely a matter of waste disposal and emissions but also involves significant concerns regarding energy wastage and resource extraction consumption. Through the framework of ESG (Environmental, Social, and Governance), this study explores effective forms and designs for the reutilization of existing ceramic waste materials. It analyzes the associated environmental, social, and governance issues and proposes a series of design strategies for the reutilization of ceramic waste materials based on ESG principles. This paper aims to provide new insights and methodologies for the sustainable development of the ceramic industry.

Hot hydrogen testing of Mo30W matrix surrogate cermets

High temperature hydrogen exposure is one of the most challenging material issues for nuclear thermal propulsion (NTP) fuel development. Under legacy NTP programs, ceramic-metallic (cermet) fuel forms with a refractory metal matrix and dispersed uranium dioxide (UO2) fuel particles were developed and showed promising performance following hot hydrogen testing. However, since the conclusion of those programs, established fabrication techniques, material feedstocks, and the ability to use highly enriched have been reduced or lost all together. In this study, a cermet consisting of a solid solution alloy of molybdenum with 30 wt percent tungsten (Mo30W) was fabricated using spark plasma sintering. Fabrication process parameters were selected to optimize the cermet microstructure using lessons learned from historic NTP programs. Yttria stabilized zirconia particles (50 to 70 % volumetric loading) were used as a fuel particle surrogate. To evaluate whether as-fabricated microstructures exhibited similar resilience as legacy cermet fuels to a hot hydrogen environment, samples were exposed to hot flowing hydrogen from 1920 to 2500 °C (∼2290 to 2770 K). The cermets performed well with minimal mass loss, minor to no cracking, and good retention of internal surrogate particles. Based on these findings, recommendations for future studies with Mo30W-UO2 cermets as an NTP fuel form are provided.