Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Article Types

Countries / Regions

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Search Results (309)

Search Parameters:
Keywords = standard impurity

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
27 pages, 7495 KB  
Article
Comparative Stability and Quality Assessment of Powder–Liquid Double-Chamber Bag Versus Traditional Meropenem Infusions: Implications for Critical Care and Individualized Dosing
by Xiaokai Ren, Xiao Li, Liting Zhang, Xiaofei Zhao, Lei Zhang and Zhanjun Dong
Pharmaceutics 2026, 18(3), 382; https://doi.org/10.3390/pharmaceutics18030382 - 20 Mar 2026
Viewed by 59
Abstract
Background: Maintaining therapeutic meropenem plasma concentrations requires prolonged infusion, but stability concerns exist between preparation and administration. This study compared the stability and operability of ready-to-use powder–liquid double-chamber bag (DCB) infusions versus traditional powder-for-injection (PFI) meropenem under clinical conditions. Methods: Infusions [...] Read more.
Background: Maintaining therapeutic meropenem plasma concentrations requires prolonged infusion, but stability concerns exist between preparation and administration. This study compared the stability and operability of ready-to-use powder–liquid double-chamber bag (DCB) infusions versus traditional powder-for-injection (PFI) meropenem under clinical conditions. Methods: Infusions at clinically relevant concentrations were stored at 2–8 °C, 25 ± 5 °C, and 40 ± 2 °C for 12 h. Stability assessments included appearance, pH, osmolality, insoluble particle count, meropenem content (HPLC), and impurity A level. Results: DCBs demonstrated superior content uniformity, significantly fewer insoluble particles (p < 0.05), and greater operational simplicity compared to PFI. Refrigeration maintained meropenem content > 95% and effectively suppressed impurity formation for up to 12 h. However, at both room temperature and elevated temperature, impurity A exceeded pharmacopoeial limits within 2 h, particularly at higher concentrations. An innovative bedside solvent volume adjustment method enabled DCBs to deliver high-concentration infusions, facilitating individualized critical care dosing. Conclusions: Compared with traditional powder injection formulations, the Meropenem powder–liquid dual-chamber bag offers more convenient operation under routine preparation conditions and poses a lower risk of contamination during the preparation process. Its stability is more sensitive to storage temperature, requiring strict adherence to refrigeration conditions. When stored under standardized conditions, the dual-chamber bag can better ensure drug efficacy stability and medication safety, making it particularly suitable for clinical emergency use and standardized workflow management. Full article
Show Figures

Figure 1

18 pages, 1563 KB  
Article
Composition-Aware SDAS Prediction in Recycled Aluminum Alloys via Physics-Informed Machine Learning Guided by Analytical Solidification Physics
by Hamed Rezvanpour, Alberto Vergnano, Paolo Veronesi and Francesco Leali
Machines 2026, 14(3), 311; https://doi.org/10.3390/machines14030311 - 10 Mar 2026
Viewed by 198
Abstract
The mechanical performance of secondary aluminum alloys depends on Secondary Dendrite Arm Spacing (SDAS). Commercial casting simulations accurately predict local thermal history but typically neglect the influence of compositional variability on SDAS by using fixed material constants. This study introduces a physics-informed machine [...] Read more.
The mechanical performance of secondary aluminum alloys depends on Secondary Dendrite Arm Spacing (SDAS). Commercial casting simulations accurately predict local thermal history but typically neglect the influence of compositional variability on SDAS by using fixed material constants. This study introduces a physics-informed machine learning framework to bridge macroscopic process simulation and microscopic solidification physics. A computational Design of Experiments covering 500 AlSi7 alloy variants was generated, and a theoretical SDAS ground truth was calculated using an analytical model incorporating the growth restriction factor. A Gradient Boosting Regressor surrogate was trained to predict the physics-informed SDAS from thermal and chemical inputs. The analysis reveals a solute sensitivity gap, where standard simulations misestimate SDAS by up to 20% for high-impurity batches. The surrogate model captures this variance (R2=0.95, MAE=0.24μm), enabling rapid, composition-specific microstructural prediction without additional simulation cost. This approach supports the reliable simulation of casting with secondary alloys, where the composition can be hardly considered constant. Full article
Show Figures

Figure 1

14 pages, 2944 KB  
Article
Nano-Pigment Cr2O3 Preparation from Chromium Slag by Alkaline Roasting, Water Leaching, Glucose Reduction and Vacuum Calcination
by Huiwen Li, Zhe Gao, Shaoxiong Li, Haocheng Qin, Qianfang Yan, Zhaowang Dong, Xiangfeng Kong, Bin Yang and Hongwei Yang
Metals 2026, 16(2), 237; https://doi.org/10.3390/met16020237 - 20 Feb 2026
Viewed by 268
Abstract
Metallurgical chromium slag is a hazardous by-product generated during the production of chromium salts and metallic chromium, containing significant amounts of leachable Cr(VI), which poses severe environmental and human health risks. To address this challenge, this study presents an integrated “alkaline roasting, water [...] Read more.
Metallurgical chromium slag is a hazardous by-product generated during the production of chromium salts and metallic chromium, containing significant amounts of leachable Cr(VI), which poses severe environmental and human health risks. To address this challenge, this study presents an integrated “alkaline roasting, water leaching with impurity removal, glucose reduction and vacuum calcination” process for its direct preparation to nano-pigment-grade Cr2O3. The reduction process was systematically optimized by investigating the effects of critical parameters: glucose dosage, HCl concentration, reduction temperature and time. Optimal conditions were established as 2.5 g of C6H12O6, 20 mL of 12 M HCl, 55 °C and 4 h, achieving the Cr(VI) reduction efficiency of 99.66%. Comprehensive characterization of the final product via XRD, SEM-EDS and XRF confirmed its high quality. The Cr2O3 exhibited a purity of 99.31%, well-developed crystallinity and a uniform sub-micron particle size distribution, fully meeting industrial standards for pigment applications. By substituting conventional hazardous reductants with glucose, this route demonstrates enhanced safety, environmental compatibility and cost-effectiveness. The proposed methodology not only provides a practical and scalable solution for the valorization of hazardous chromium slag but also contributes to the advancement of green processing technologies in the metallurgical sector, supporting the transition towards a circular economy. Full article
Show Figures

Figure 1

17 pages, 2764 KB  
Article
Pressure-Swing Adsorption Process for Producing Fuel Cell-Grade Hydrogen from Steam Methane Reforming Gas
by Hua Li, Tongbo Wu, Wenbin Li and Donghui Zhang
Energies 2026, 19(4), 1074; https://doi.org/10.3390/en19041074 - 19 Feb 2026
Viewed by 342
Abstract
Hydrogen energy is acknowledged as being the cleanest energy source. As hydrogen fuel cell technology advances, the development of low-cost, high-quality hydrogen purification technologies has grown increasingly critical. Targeting the separation of steam methane reforming gas mixture with a typical composition of H [...] Read more.
Hydrogen energy is acknowledged as being the cleanest energy source. As hydrogen fuel cell technology advances, the development of low-cost, high-quality hydrogen purification technologies has grown increasingly critical. Targeting the separation of steam methane reforming gas mixture with a typical composition of H2/CO2/CH4/CO = 76%/20%/3.5%/0.5%, a 6-bed-13-step pressure-swing adsorption process featuring four pressure-equalization steps was designed, in which a multi-layer adsorbent packing strategy was adopted to investigate the purification performance. The effects of feed flow rate, adsorbent packing combination, and purge-to-feed ratio on hydrogen purity and recovery, and on the impurity content level were analyzed. Furthermore, the gas-phase and solid-phase concentration distributions of each adsorbent layer under cyclic steady state were studied in detail, and the variation characteristics of their adsorption–desorption behaviors were systematically elaborated. Eventually, the optimal adsorbent combination and process condition configurations were determined. The results show that the proposed process can achieve a hydrogen purity of 99.99971%, with a concentration of CO of less than 0.2 ppm, which meets the fuel cell-grade hydrogen standard. Full article
(This article belongs to the Section A5: Hydrogen Energy)
Show Figures

Figure 1

21 pages, 3538 KB  
Article
Mobile AI-Powered Impurity Removal System for Decentralized Potato Harvesting
by Joonam Kim, Kenichi Tokuda, Yuichiro Miho, Giryeon Kim, Rena Yoshitoshi, Shinori Tsuchiya, Noriko Deguchi and Kunihiro Funabiki
Agronomy 2026, 16(3), 383; https://doi.org/10.3390/agronomy16030383 - 5 Feb 2026
Viewed by 481
Abstract
An advanced artificial intelligence (AI)-powered mobile automated impurity removal system was developed and integrated into potato harvesting machinery for decentralized agricultural environments in Japan. As opposed existing stationary AI systems in centralized processing facilities, this mobile prototype enables on-field impurity removal in real [...] Read more.
An advanced artificial intelligence (AI)-powered mobile automated impurity removal system was developed and integrated into potato harvesting machinery for decentralized agricultural environments in Japan. As opposed existing stationary AI systems in centralized processing facilities, this mobile prototype enables on-field impurity removal in real time through a systematic dual-evaluation methodology. The system integrates the YOLOX-small architecture with precision pneumatic actuators and achieves 40–50 FPS processing under dynamic field conditions. Algorithm validation across 10 morphologically diverse potato varieties (Danshaku, Harrow Moon, Hokkaikogane, Kitaakari, Kitahime, May Queen, Sayaka, Snowden, Snow March, and Toyoshiro) using count-based analysis showed exceptional recognition, with potato misclassification rates of 0.08 ± 0.03% (range: 0.01–0.32%) and impurity detection rates of 89.99 ± 1.25% (range: 80.00–93.30%). Cross-farm validation across seven commercial farms in Hokkaido confirmed robust algorithm consistency (PMR: 0.08 ± 0.03%, IDR: 90.56 ± 0.82%) without farm-specific calibration, establishing variety-independent and environment-independent operation. Field validation using weight-based analysis during actual harvesting at 1–4 km/h confirmed successful AI-to-field translation, with 0.22–0.42% potato misclassification and adaptive impurity removal of 71.43–85.29%. The system adapted intelligently, employing conservative sorting under high-impurity loads (71.43% removal, 0.33% misclassification) to prioritize potato preservation while maximizing efficiency under standard conditions (85.29% removal, 0.30% misclassification). The dual-evaluation framework successfully bridged the gap between AI accuracy in laboratory settings and effectiveness in agricultural operations. The proposed AI algorithm surpassed project targets for all tested conditions (>60% impurity removal, <1% potato misclassification). This successful integration demonstrates technical feasibility and commercial viability for widespread agricultural automation, with a validated 50% reduction in labor (four workers to two workers). This implementation provides a comprehensive validation methodology for next-generation autonomous harvesting systems. Full article
(This article belongs to the Collection AI, Sensors and Robotics for Smart Agriculture)
Show Figures

Figure 1

19 pages, 5000 KB  
Article
Magnetic Nanoparticle-Integrated Microfluidic Chip Enables Reliable Isolation of Plasma Cell-Free DNA for Molecular Diagnostics
by Amir Monfaredan, Sena Şen, Arash Adamnejad Ghafour, Ebru Cingöz Çapan, Muhammed Ertuğrul Çapan, Ridvan Şeçkin Özen, Şeref Buğra Tuncer and Oral Öncül
Diagnostics 2026, 16(3), 460; https://doi.org/10.3390/diagnostics16030460 - 2 Feb 2026
Viewed by 520
Abstract
Background/Objectives: Cell-free DNA (cfDNA) is a valuable biomarker for cancer diagnosis and therapy monitoring; however, its low abundance and fragmented nature present major challenges for reliable isolation, particularly from limited plasma volumes. Here, we report the development and evaluation of a novel [...] Read more.
Background/Objectives: Cell-free DNA (cfDNA) is a valuable biomarker for cancer diagnosis and therapy monitoring; however, its low abundance and fragmented nature present major challenges for reliable isolation, particularly from limited plasma volumes. Here, we report the development and evaluation of a novel magnetically assisted microfluidic chip with a three-inlet design for efficient cfDNA extraction from small-volume plasma samples. Methods: The platform enables controlled infusion of plasma, lysis buffer, and magnetic nanoparticle suspensions at defined flow rates. An external magnetic field selectively captures cfDNA-bound nanoparticles while efficiently removing background impurities. Results: Direct comparison with two in vitro diagnostic (IVD)-certified commercial cfDNA extraction kits showed that the microfluidic system achieved comparable cfDNA yields at standard plasma volumes and superior performance at reduced input volumes. High DNA purity and integrity were confirmed by quantitative PCR amplification of a housekeeping gene and clinically relevant targets. The complete workflow required approximately 9 min, used minimal equipment, reduced contamination risk, and enabled rapid processing with future potential for parallel multi-chip configurations. Conclusions: These findings establish the proposed microfluidic platform as a rapid, reproducible, and scalable alternative to conventional cfDNA extraction methods. By significantly improving recovery efficiency from small plasma volumes, the system enhances the clinical feasibility of liquid biopsy applications in cancer diagnostics and precision medicine. Full article
(This article belongs to the Section Point-of-Care Diagnostics and Devices)
Show Figures

Figure 1

17 pages, 5285 KB  
Article
Challenges and Practices in the Analysis of Silicon Kerf from the PV Industry by Combinatorial Analytical Methods
by Tinotenda Mubaiwa, Marisa Di Sabatino, Sergey Khromov, Marthe Nybrodahl, Alexander Azarov and Jafar Safarian
Materials 2026, 19(3), 541; https://doi.org/10.3390/ma19030541 - 29 Jan 2026
Viewed by 343
Abstract
Exploitation of waste streams has gained prominence not only in sustainable use of resources but also as a potential source of raw materials. Silicon kerf is one such waste stream and its recycling has been quite topical in recent years. In the present [...] Read more.
Exploitation of waste streams has gained prominence not only in sustainable use of resources but also as a potential source of raw materials. Silicon kerf is one such waste stream and its recycling has been quite topical in recent years. In the present study, the characterization of different industrial kerf samples was carried out using several techniques. The average metallic impurity concentration was approximately 400 ppmw with average particle size (D50) of 3.5 µm and surface area of approximately 33 m2/g. The inhomogeneity of kerf was shown to pose challenges like potential isotope interferences during analysis as well as being susceptible to high uncertainties and relative standard deviation (RSD). Remedies and best practices were recommended for successful characterization of such inhomogeneous materials. Full article
(This article belongs to the Special Issue Waste Materials: Recycle and Valorize)
Show Figures

Figure 1

24 pages, 2380 KB  
Article
Gas Flow Metering Using National Standards and Gas Mixtures Containing Hydrogen
by Maxime Mussard, Marc De Huu, Rémy Maury, Loucie Cirkeline Nordhjort Mjølna, Tomáš Valenta, Mahdi Sadri, Eric Starke, Pieter Pinson, Marcel Workamp and Adriaan M. H. van der Veen
Hydrogen 2026, 7(1), 19; https://doi.org/10.3390/hydrogen7010019 - 28 Jan 2026
Viewed by 434
Abstract
We present the first European intercomparison of primary flow measurement standards with hydrogen-enriched natural gas (up to 20% hydrogen in molar fraction) and natural gas with pressure up to 60 bar and volume flow rates in the range (5 to 160) m3 [...] Read more.
We present the first European intercomparison of primary flow measurement standards with hydrogen-enriched natural gas (up to 20% hydrogen in molar fraction) and natural gas with pressure up to 60 bar and volume flow rates in the range (5 to 160) m3/h. We describe the principles of operation of the primary standards and present the transfer standards, a rotary meter and an ultrasonic meter, used for the intercomparison. In many instances, the overlap between the different laboratories is satisfactory, but the collected results are limited and do not allow us to make advanced conclusions. In addition, we investigate the effect of nitrogen impurities (2% in molar fraction) on the performance of low-pressure gas meters for pure hydrogen using newly developed measurement standards. We present the methods and results of this investigation. We show that nitrogen impurities affect the volume flow measurements of an ultrasonic meter but seem to have little effect on a thermal mass flow meter. This paper explores future opportunities and challenges in international intercomparisons involving hydrogen blends and highlights key issues and solutions with hydrogen gas metering in the presence of impurities. Full article
Show Figures

Figure 1

18 pages, 1165 KB  
Article
Comprehensive Toxicological Evaluation of 3D-Printed Hydroxyapatite (3DPHA) for Bone Grafting Applications
by Faungchat Thammarakcharoen, Autcharaporn Srion, Waraporn Suvannapruk, Watchara Chokevivat, Wiroj Limtrakarn and Jintamai Suwanprateeb
Int. J. Mol. Sci. 2026, 27(2), 636; https://doi.org/10.3390/ijms27020636 - 8 Jan 2026
Viewed by 515
Abstract
Binder jet 3D printing combined with a low-temperature phase transformation process has emerged as a promising route for producing 3D-printed hydroxyapatite (3DPHA) scaffolds with controlled architecture for bone grafting applications. However, the toxicological profile of this unique binder jet-derived material has not yet [...] Read more.
Binder jet 3D printing combined with a low-temperature phase transformation process has emerged as a promising route for producing 3D-printed hydroxyapatite (3DPHA) scaffolds with controlled architecture for bone grafting applications. However, the toxicological profile of this unique binder jet-derived material has not yet been established. In this study, we conducted a comprehensive compositional and toxicological assessment of 3DPHA fabricated via the calcium sulfate transformation route. The material exhibited phase-pure hydroxyapatite (HA) with a Ca/P ratio consistent with non-stoichiometric HA and low levels of trace elemental impurities. In vitro assays revealed no cytotoxic, irritant, sensitizing, or mutagenic effects. This work provides a standardized toxicological and compositional safety validation of 3DPHA. By linking compositional purity to biological safety and demonstrating compliance with international benchmarks, this study establishes a regulatory foundation confirming that 3DPHA is chemically pure, biologically safe, and ready for clinical translation as a bone-graft material. Full article
Show Figures

Figure 1

22 pages, 1115 KB  
Review
Sustainable Cellulose Production from Agro-Industrial Waste: A Comprehensive Review
by Akmaral Darmenbayeva, Reshmy Rajasekharan, Zhanat Idrisheva, Roza Aubakirova, Zukhra Dautova, Gulzhan Abylkassova, Manira Zhamanbayeva, Irina Afanasenkova and Bakytgul Massalimova
Polymers 2026, 18(2), 153; https://doi.org/10.3390/polym18020153 - 6 Jan 2026
Viewed by 808
Abstract
The growing demand for sustainable and renewable materials has intensified interest in agro-industrial waste as an alternative source of cellulose. This review critically examines current approaches to cellulose production from major agro-industrial residues, including cereal straw, corn residues, rice waste, sugarcane bagasse, and [...] Read more.
The growing demand for sustainable and renewable materials has intensified interest in agro-industrial waste as an alternative source of cellulose. This review critically examines current approaches to cellulose production from major agro-industrial residues, including cereal straw, corn residues, rice waste, sugarcane bagasse, and oilseed by-products. Emphasis is placed on the relationship between feedstock composition and extraction efficiency, highlighting how lignin distribution, hemicellulose content, and mineral impurities influence pretreatment severity, cellulose yield, and process sustainability. The review systematically analyzes chemical, enzymatic, and mechanical processing routes, with particular attention being paid to pretreatment strategies, fibrillation intensity, and yield variability. Beyond cellulose recovery, key sustainability indicators—such as energy demand, water and chemical consumption, waste generation, and chemical recovery—are evaluated to provide a system-level perspective on process efficiency. The analysis demonstrates that cellulose yield alone is an insufficient criterion for sustainable process design and must be considered alongside environmental and techno-economic metrics. Advanced applications of agro-waste-derived cellulose are discussed using a feedstock-driven approach, showing that high functional performance can often be achieved with moderately processed cellulose tailored to specific end uses. Finally, the review addresses challenges related to feedstock heterogeneity, mineral management, standardization, and industrial scale-up, underscoring the importance of biorefinery integration, closed-loop resource management, and harmonized quality descriptors. These insights provide a foundation for the development of scalable and sustainable cellulose production pathways based on agro-industrial waste. Full article
(This article belongs to the Section Circular and Green Sustainable Polymer Science)
Show Figures

Figure 1

21 pages, 367 KB  
Review
Review of CO2 Corrosion Modeling for Carbon Capture, Utilization and Storage (CCUS) Infrastructure
by Kenneth René Simonsen, Mohammad Ostadi, Maciej Zychowski, Simon Pedersen and Mads Valentin Bram
Processes 2026, 14(1), 170; https://doi.org/10.3390/pr14010170 - 4 Jan 2026
Viewed by 935
Abstract
CO2 corrosion remains a critical challenge for the safe and reliable operation of Carbon Capture, Utilization, and Storage (CCUS) infrastructure. This review summarizes CO2 corrosion implications from material selection, exposure time, CO2 phase behavior, flow conditions, and impurities such as [...] Read more.
CO2 corrosion remains a critical challenge for the safe and reliable operation of Carbon Capture, Utilization, and Storage (CCUS) infrastructure. This review summarizes CO2 corrosion implications from material selection, exposure time, CO2 phase behavior, flow conditions, and impurities such as H2O, O2, SOx, NOx, and H2S. CO2 corrosion modeling has, since early works by de Waard in 1975, expanded to a wide range of models and software tools, many of which have already been reviewed and compared. This work provides a historical timeline and a comparative summary of models and software tools to assist in selecting models for CCUS applications. Modeling approaches are classified into empirical, semi-empirical, and mechanistic categories, with their assumptions, strengths, and limitations. CO2 corrosion modeling has persistent challenges relating to data quality, data quantity, and parameter interactions, which reduce model accuracy, especially for machine learning approaches. The provided perspective emphasizes that machine learning and hybrid modeling approaches for CO2 corrosion prediction are gaining popularity, and their effectiveness is currently limited by the quality and quantity of available corrosion data. The provided opportunities include recommendations for standardized experimental procedures and hybrid modeling strategies that combine physics-based insights from mechanistic modeling approaches with data-driven machine learning approaches. Full article
(This article belongs to the Section Energy Systems)
Show Figures

Figure 1

15 pages, 242 KB  
Review
Exogenous Impurities in Baijiu: Sources, Detection, and Safety Strategies
by Yabin Zhou, Jin Hua and Liping Xu
Beverages 2026, 12(1), 2; https://doi.org/10.3390/beverages12010002 - 24 Dec 2025
Viewed by 918
Abstract
Baijiu, China’s traditional distilled spirit, is produced through solid-state fermentation and distillation of grains, resulting in a highly complex chemical and sensory profile. However, exogenous impurities introduced via raw materials, water, equipment, packaging, or the surrounding environment pose significant challenges to both safety [...] Read more.
Baijiu, China’s traditional distilled spirit, is produced through solid-state fermentation and distillation of grains, resulting in a highly complex chemical and sensory profile. However, exogenous impurities introduced via raw materials, water, equipment, packaging, or the surrounding environment pose significant challenges to both safety and quality. These impurities, including heavy metals, plasticizers, pesticide residues, mycotoxins, environmental pollutants, and un-authorized food additives, are associated with neurotoxicity, carcinogenicity, endocrine disruption, and sensory defects. This narrative review synthesizes current knowledge on their sources, reported concentration ranges in Baijiu (generally at trace µg/kg–mg/kg levels), analytical detection methods with sub-mg/kg sensitivity, and control strategies for these substances. Regulatory frameworks, including China’s standards, are critically assessed, with emphasis on gaps such as the lack of explicit limits for certain classes of impurities. Case studies of contamination incidents are discussed to illustrate practical risks and monitoring gaps. Emerging trends, including low- and zero-alcohol Baijiu, are also considered in relation to changing impurity profiles and detection requirements. Recommendations include tightening regulatory limits, adopting portable and real-time detection technologies, and promoting the development of “pure Baijiu” that meets international safety and quality expectations. Future research priorities center on high-resolution mass spectrometry, advanced real-time monitoring, and eco-friendly analytical solutions, ensuring that Baijiu maintains both cultural heritage and global competitiveness. Full article
13 pages, 1846 KB  
Article
A Validated Isocratic HPLC–UV Method for the Simultaneous Quantification of Corilagin and Geraniin in Geranium wilfordii Maxim. Extract
by Jung-Min Kim, Kun-Ho Song, Yong-Seok Choi, Cheon-Kwang Ko and Bong-Seop Lee
Molecules 2026, 31(1), 31; https://doi.org/10.3390/molecules31010031 - 22 Dec 2025
Cited by 1 | Viewed by 456
Abstract
Geranium wilfordii Maxim. is a traditional medicinal plant rich in ellagitannins such as corilagin (CG) and geraniin (GR), which possess antioxidant and anti-inflammatory properties. However, accurate quantification of CG and GR in complex herbal matrices is hindered by co-eluting impurities and poor UV [...] Read more.
Geranium wilfordii Maxim. is a traditional medicinal plant rich in ellagitannins such as corilagin (CG) and geraniin (GR), which possess antioxidant and anti-inflammatory properties. However, accurate quantification of CG and GR in complex herbal matrices is hindered by co-eluting impurities and poor UV resolution. Here, we developed and validated a simple isocratic HPLC–UV method for their simultaneous determination in G. wilfordii extract. Separation was achieved on a Polaris 3 C18-A column (250 mm × 4.6 mm, 3 µm) using acetonitrile/0.2% formic acid in water (11:89, v/v) with UV detection at 270 nm. The method showed excellent linearity (25–300 µg/mL, R2 > 0.995), precision (RSD < 2.7%), accuracy (recovery 99.5–101.2%), and low detection limits (<3 µg/mL). Previous approaches have relied on gradient HPLC or MS-based techniques, often requiring long run times, costly instrumentation, or additional purification (e.g., HSCCC). In contrast, this study demonstrates a validated isocratic method that enables baseline separation and simultaneous quantification of CG and GR in a single run. This robust and simplified analytical strategy provides a practical tool for routine quality control and phytochemical standardization, with potential applications across pharmaceutical, food, and cosmetic industries. Full article
(This article belongs to the Section Analytical Chemistry)
Show Figures

Figure 1

15 pages, 2122 KB  
Article
Effects of Localized Overheating on the Particle Size Distribution and Morphology of Impurities in Transformer Oil
by Shangquan Feng, Ruijin Liao, Lijun Yang, Chen Chen and Xinxi Yu
Energies 2025, 18(24), 6566; https://doi.org/10.3390/en18246566 - 16 Dec 2025
Viewed by 347
Abstract
Power transformers are critical components of power grids, and their operational status characterization and fault diagnosis are crucial for power system reliability. Oil quality assessment is a crucial method for determining transformer status, and the detection of impurity particles in oil has historically [...] Read more.
Power transformers are critical components of power grids, and their operational status characterization and fault diagnosis are crucial for power system reliability. Oil quality assessment is a crucial method for determining transformer status, and the detection of impurity particles in oil has historically been a key approach. However, recent field tests have revealed the presence of numerous impurity particles less than 5 μm in transformer oil. Current power standards do not address these micron-sized particles, and their sources and mechanisms of action are largely unresolved. Therefore, this paper designed a localized overheating experiment, incorporating microflow imaging technology, to investigate the generation patterns of impurity particles under localized overheating and their quantitative correlation with heat. Field oil samples were also collected and tested to further explore the potential application of these micron-sized particles in transformer overheating assessment. The research results show that insulating oil can decompose and produce impurity particles at temperatures as low as 140 °C. When the temperature is below 140 °C, the number of particles at different heat levels is not significantly different from that of the non-overheated oil sample. However, when the temperature exceeds 140 °C, the number of particles increases significantly with increasing heat. Among the generated particles, particles with a diameter of less than 5 μm account for over 50% of the total number, and their number increases significantly with increasing heat. Their morphology is characterized by a smooth, regular, and spherical shape. Field test results of overheated oil samples are consistent with laboratory tests. Micron-sized particles are highly sensitive to changes in overheating conditions and have the potential to be used as a new characteristic parameter of transformer overheating conditions. In summary, this paper reveals the formation mechanism of impurity particles in insulating oil under localized overheating conditions. It was found that insulating oil can also decompose and generate impurity particles at 140 °C, with the pyrolysis products mainly consisting of particles smaller than 5 μm in diameter, which are not currently considered a concern in existing standards. Further research indicates that these micron-sized particles exhibit high sensitivity to changes in overheating conditions, demonstrating potential application value as a novel characteristic parameter of transformer overheating. Full article
Show Figures

Figure 1

22 pages, 1393 KB  
Review
Biogas Upgrading and Bottling Technologies: A Critical Review
by Yolanda Mapantsela and Patrick Mukumba
Energies 2025, 18(24), 6506; https://doi.org/10.3390/en18246506 - 12 Dec 2025
Cited by 1 | Viewed by 1414
Abstract
Biogas upgrading and bottling represent essential processes in transforming raw biogas produced via the anaerobic digestion of organic waste into high-purity biomethane (≥95% CH4), a renewable energy source suitable for applications in cooking, transportation, and electricity generation. Upgrading technologies, such as [...] Read more.
Biogas upgrading and bottling represent essential processes in transforming raw biogas produced via the anaerobic digestion of organic waste into high-purity biomethane (≥95% CH4), a renewable energy source suitable for applications in cooking, transportation, and electricity generation. Upgrading technologies, such as membrane separation, pressure swing adsorption (PSA), water and chemical scrubbing, and emerging methods, like cryogenic distillation and supersonic separation, play a pivotal role in removing impurities like CO2, H2S, and moisture. Membrane and hybrid systems demonstrate high methane recovery (>99.5%) with low energy consumption, whereas chemical scrubbing offers superior gas purity but is limited by high operational complexity and cost. Challenges persist around material selection, safety standards, infrastructure limitations, and environmental impacts, particularly in rural and off-grid contexts. Bottled biogas, also known as bio-compressed natural gas (CNG), presents a clean, portable alternative to fossil fuels, contributing to energy equity, greenhouse gases (GHG) reduction, and rural development. The primary aim of this research is to critically analyze and review the current state of biogas upgrading and bottling systems, assess their technological maturity, identify performance optimization challenges, and evaluate their economic and environmental viability. The research gap identified in this study demonstrates that there is no comprehensive comparison of biogas upgrading technologies in terms of energy efficiency, price, scalability, and environmental impact. Few studies directly compare these technologies across various operational contexts (e.g., rural vs. urban, small vs. large scale). Additionally, the review outlines insights into how biogas can replace fossil fuels in transport, cooking, and electricity generation, contributing to decarbonization goals. Solutions should be promoted that reduce methane emissions, lower operational costs, and optimize resource use, aligning with climate targets. This synthesis highlights the technological diversity, critical barriers to scalability, and the need for robust policy mechanisms to accelerate the deployment of biogas upgrading solutions as a central component of a low-carbon, decentralized energy future. Full article
Show Figures

Figure 1

Back to TopTop