This study focuses on the solid phase extraction of biogenic amines (BAs) using a sol-gel adsorbent immobilized with a hydrazone ligand, named 2-hydroxy-5-nitrobenzaldehyde-2,4-dinitrophenylhydrazone. The hydrazone compound was synthesized and characterized through Fourier Transform Infrared Spectroscopy (FT-IR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The efficiency of the sorbent material for extracting BAs was evaluated using the solid phase extraction (SPE) method. Key experimental parameters affecting BA extraction, including pH, equilibrium time, ligand concentration, and biogenic amine (BA) concentration, were systematically investigated. The results indicated a strong recovery of BAs from aqueous samples, demonstrating a significant affinity between the sol-gel matrix containing the hydrazone ligand and the target analytes. The findings demonstrate that incorporating the hydrazone ligand resulted in a marked enhancement of extraction efficiency at a concentation of 17 & times; 10(-3) M. Notably, the method exhibited high selectivity for aliphatic biogenic amines such as putrescine (PUT), cadaverine (CAD), and spermidine (SPD). This extraction method was successfully applied to food samples, yielding good recovery rates.
The development of aluminum-based cladding materials for nuclear fuel confinement is advancing in line with the increasing demand for high-density fuels. Alloying aluminum with magnesium (Mg), iron (Fe), and nickel (Ni) is expected to improve mechanical strength and thermal stability, thereby compensating for the higher hardness associated with high-density fuels. Heat treatment is a proven strategy to further enhance the performance of Al-based alloys in nuclear applications. In this study, Al-Mg-Fe-Ni alloys were fabricated by arc melting, homogenized, rolled, and subjected to heat treatment at 500 degrees C for 1.5, 3, and 4.5 h. Structural analysis using XRD and GSAS confirmed the formation of a substitutional solid solution with partial preferred orientation. Heat treatment decreased hardness due to recovery and partial recrystallization, but increased bulk density. The sample treated for 1.5 h exhibited the best balance, with a hardness of 82.81 +/- 0.06 HV and a density of 2.7232 +/- 0.0002 g/cm(3). These results demonstrate that controlled thermal treatment can be used to optimize the structure-property relationship of Al-based alloys, offering valuable insights for the design of advanced cladding materials for high-density nuclear fuels.
Modern test methods for air conditioners and heat pumps must reconcile two competing demands: accurately reflecting real operating behavior and ensuring practicality, repeatability, and interlaboratory comparability. Conventional fixed-speed, steady-state rating procedures fall short of this objective, as they exclude control dynamics and interactions with buildings and distribution systems, thereby limiting their representativeness of in-use performance.This review critically examines the limitations of current testing standards and synthesizes recent research and technical advances aimed at improving performance characterization and seasonal efficiency assessment. Emphasis is placed on load-based testing methodologies, emulator-based approaches, and hardware-in-the-loop (“field test in the lab”) concepts, which enable active-control operation under reproducible yet realistic conditions. Evidence from laboratory demonstrations, interlaboratory comparisons, and emerging standardization efforts is consolidated to assess the technical maturity, robustness, and scalability of these methods. The discussion also reflects ongoing international initiatives, including International Energy Agency Annex 88, “Evaluation and Demonstration of Actual Energy Efficiency of Heat Pump Systems in Buildings,” and the International Organization for Standardization Informal Meeting on “Load-based Test Methods.”Based on the reviewed methods, the paper identifies pathways toward next-generation testing frameworks that better recognize advanced system architectures and control strategies, support evidence-based policy and standardization, and provide consumers with performance metrics that more closely align with real-world energy outcomes.
Benthic invertebrate assemblages are often assessed in coral reef monitoring owing to their ecological and economic importance, yet a biotic index for assessing the ecological health of these assemblages has not yet been developed. This index is useful for stakeholders to help design management actions, including conservation and restoration of target taxa. In this study, we developed a new biotic index to assess the ecological health of benthic invertebrates on the basis of coral reef monitoring data from 38 locations (8–19 sites per location) across Indonesia (n = 464 sites). At each site, a belt transect of 2 m × 70 m was performed to collect invertebrate data (Holothuroidea, Tridacninae, Palinuridae, Trochidae, Acanthaster planci, Diadema, Drupella, and Linckia laevigata) and benthic habitat data. The index was constructed on the basis of the ecological quality ratio concept (the ratio between observed and reference values) using 11 metrics from training data (n = 389 sites) and validated by that on the basis of testing data (n = 75 sites). The index was also validated by evaluating the linear regression between the index and anthropogenic pressures, and ranged between 0 (very poor) and 1 (very good). The index ecological quality ratio of invertebrates (EQRinv) decreased with declining water quality and increasing fishing pressure but increased with habitat heterogeneity (p < 0.05). This suggests that the EQRinv could indicate the presence of poor water quality, overfishing, and habitat modification in coral reef ecosystems. Based on our index, the ecological health of benthic invertebrate assemblages in Indonesian coral reef ecosystems was fair, with a mean EQRinv of 0.47. The EQRinv can improve the assessment of coral reef health in Indonesia and can also be applied across the tropical Indo-Pacific to support coral reef conservation and management.
The escalating global demand for renewable energy positions wave power as a critical sustainable resource. However, the widespread adoption of Wave Energy Converters (WECs) is impeded by challenges in optimizing hydrodynamic efficiency and reducing lifecycle costs. This paper provides a comprehensive review of the technological evolution of WECs, focusing on design optimization methods and emergent trends. A three-step methodology was employed, integrating descriptive analysis, bibliometric mapping, and a systematic review of optimization strategies. Our findings reveal a significant research trajectory towards hybrid energy systems, which co-locate WECs with offshore wind platforms to enhance energy capture and economic viability. The study underscores the pivotal role of advanced computational techniques, such as hybrid optimization algorithms, in elevating WEC performance. Nevertheless, critical gaps persist, primarily the lack of extensive experimental validation for numerical models and the need for algorithms with faster convergence. This review synthesizes the current state-of-the-art, offering valuable insights to direct future research toward more efficient and commercially viable WEC technologies.
