jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Dalal Desouqi | Mohamad Amran Mohd Salleh | Muhammad Hatta Roselee | Ahmed Yahya | Bushra Abdo Alsalam | Suraya Abdul Rashid
Source: Scientific African (article, 2025-02-27)
Field: Materials Science — Materials Chemistry

Mineralogical and petrographic characterisation of flake graphite in the graphite mica schist rocks from the Nubian Desert, Sudan The Nubian Desert in Sudan, spanning from the Nile River in Wadi Halfa to the eastern Red Sea region, hosts graphite-bearing rocks that can potentially meet the increasing demand for natural graphite, a critical mineral in green energy technologies. This study is the first to investigate the detailed mineralogical and petrographic characteristics of graphite-bearing rocks from this region using petrography, scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDX), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The Nubian Desert flake graphite is of high-grade and hosted in metamorphic graphite schist that has been subjected to an increasing regional environment of amphibolite-to-greenschist facies. The schist is of high-grade and fine-grained, with a clear foliation texture composed of graphite (10 %), quartz (35 %), mica (biotite+muscovite) (50 %), and albite (5 %). Fine graphite flakes, ranging from 50 to 150 µm in length with an average width of 46 µm, are disseminated along the schist foliation texture. The quantitative elemental contents are C (10 %), SiO 2 (60 %), Al₂O₃ (20 %), and K₂O (10 %). Approximately 84 % of the total carbon is graphite, whereas 16 % is graphitised carbon, which can be upgraded by froth flotation and acid leaching. Although the crystallinity and microcrystal structure of the graphite require further investigation, the preliminary mineralogical features meet the international standards for high-grade fine-flake graphite and suggest its suitability for advanced processing and exploration. These findings highlight the Nubian Desert as an important and underexplored graphite resource, necessitating expanded geological and industrial investigations to meet the growing demand for critical minerals required for sustainable energy technologies. Petrography ; Schist ; Flake ; Mica ; Geology ; Graphite ; Geochemistry ; Mineral ; Mineralogy ; Archaeology ; Metamorphic rock ; Metallurgy ; Materials science ; Composite material ; Geography ; Paleontology Graphite, nuclear technology, radiation studies ; Graphene research and applications ; Radiation Shielding Materials Analysis
Authors: Tzu-Yi Chang | Sebastian Lam | D. Frazer | Fei Teng | Yachun Wang | H. Gietl | Peter Hosemann | Stephanie Pitts
Source: Fusion Engineering and Design (article, 2025-06-24)
Field: Materials Science — Materials Chemistry

The role of specimen size and grain boundary characteristics in the yield strength of tungsten in microtensile tests Materials science ; Tungsten ; Yield (engineering) ; Composite material ; Grain size ; Metallurgy Microstructure and mechanical properties ; Hydrogen embrittlement and corrosion behaviors in metals ; Advanced materials and composites
Authors: Rahmat Azis Nabawi | Syahril Syahril | Hairul Abral
Source: Teknomekanik (article, 2025-12-29)
Field: Materials Science — Polymers and Plastics

Loading-dependent mechanical performance of alkali-treated areca nut husk fiber reinforced polyester composites modified with Uncaria gambir extract Natural fiber-reinforced polymer composites often experience mechanical performance limitations due to weak interfacial bonds between hydrophilic fibers and hydrophobic matrices. This study experimentally examined the effect of alkali treatment and modification using Uncaria gambir extract (UGE) on the mechanical properties and interface morphology of polyester composites reinforced with areca nut husk fiber (ANHF). Four composite configurations were prepared with a constant fiber weight fraction of 40 wt.% after alkali treatment using 6% NaOH for 24 hours, while the remaining 2 wt.% UGE was selectively applied as a fiber surface treatment, matrix additive, or a combination of both. Tensile and flexural properties were evaluated in accordance with ASTM standards, while interface morphology was examined using scanning electron microscopy (SEM). The results showed that alkali-treated composites without UGE addition had the highest tensile strength, which was attributed to increased fiber surface roughness and mechanical interlocking mechanisms. Conversely, fiber surface modification using UGE significantly increased flexural strength, indicating better stress distribution under flexural loading due to increased interface continuity. However, the addition of UGE to the matrix caused a decrease in tensile strength, which was thought to be related to a reduction in matrix stiffness. SEM observations confirm the presence of distinct interface morphology differences according to the treatment applied. These findings indicate that UGE serves primarily as a bio-based interfacial modifier, enhancing flexural performance, while its effectiveness is strongly governed by the mechanical loading mode. Ultimate tensile strength ; Flexural strength ; Fiber ; Composite number ; Husk ; Scanning electron microscope ; Natural fiber ; Surface roughness Natural Fiber Reinforced Composites ; Electrospun Nanofibers in Biomedical Applications ; Bamboo properties and applications
Authors: Pamela Raquel Rivera-Tovar | Gabriela Contreras-Contreras | Paulina Isabel Rivas-Reyes | Jara Pérez‐Jiménez | Maximiliano Martínez‐Cifuentes | José Ricardo Pérez‐Correa | María Salomé Mariotti‐Celis
Source: Preprints.org (preprint, 2025-01-08)
Field: Chemistry — Analytical Chemistry

Sustainable Recovery of Phlorotannins from&lt;em&gt; Durvillaea incurvata&lt;/em&gt;: : Integrated Extraction and Purification with Advanced Characterization The rising demand for bioactive compounds from marine resources highlights the need for sustainable separation technologies. This study introduces an integrated process combining ultrasound-assisted extraction (USAE) and resin purification (RP) to isolate phlorotannins from Durvillaea incurvata, a brown seaweed with significant biomedical potential. Using a 32.5% ethanol-water solvent system for USAE followed by RP on Diaion HP-20 resin, phlorotannins were enriched 2.4-fold, with a simultaneous removal of interfering compounds like mannitol (~100%), wich was demonstrated by FTIR and HPLC-IR analysis. Advanced characterization through UHPLC-QToF-MS/MS identified five novel phlorotannins with polymerization degrees of 3 to 8 phloroglucinol units in both USAE extracts and post-RP. Mass balance based on spectrophotometric measurements indicated a purification factor of ~2, confirming process effectiveness. RP streams showed distinct phlorotannin profiles, with one phlorotannin exceeding 70% relative abundance. However, MS/MS results showed significantly lower recoveries than spectrophotometric data, revealing a novel insight into RP purification. These findings highlight the critical role of comprehensive chemical characterization in optimizing sustainable phlorotannin extraction from seaweed. They propose a framework for scalable, eco-efficient technologies to achieve high-purity phlorotannin recovery. This approach facilitates the development of phlorotannin-based applications in the nutraceutical and pharmaceutical industries. Characterization (materials science) ; Extraction (chemistry) ; Chemistry ; Materials science ; Nanotechnology ; Chromatography Chromatography in Natural Products ; Phytochemical Studies and Bioactivities ; Morinda citrifolia extract uses
Authors: Juncheng Liu | Bing Xu | Evgeny A. Uslamin | Evgeny A. Pidko | Antonia G. Denkova | Rienk Eelkema
Source: ChemRxiv (preprint, 2025-02-19)
Field: Chemistry — Organic Chemistry

Reaction network analysis of organochloride mediated oxidation induced by ionizing radiation The generation of organoperoxy radical by irradiating aqueous solutions of organochlorides depends on the concentration of organochloride, where low concentration results in low yield of reactive oxygen species (ROS). The need of high concentration of organochloride limits the application in cancer therapy as most small molecule organochlorides show liver toxicity at elevated concentrations. To study if the oxidation is feasible at low concentration of organochloride, we proposed a reaction network where the effect of molecular oxygen is included. We hypothesized that oxygen competes with the organochloride to react with aqueous electrons, thereby causing a low yield of ROS at low organochloride concentrations. However, oxygen is necessary in the ROS formation pathway, which complicates straightforward prediction of reaction outcome. We developed a mathematic model to simulate the yield of ROS depending on organochloride and oxygen concentrations. The simulated results indicate that at low organochloride concentration, decreasing oxygen concentration leads to higher yield of ROS, with a peak at approximately 2% partial pressure of oxygen, and oxygen lower than 2% results in a sharp yield drop of ROS. Experiments using a thioether as reductant to quantify the ROS formation show good agreement with simulated data, verifying the proposed network. After irradiation in phosphate buffer saline/organochloride, a thioether caged drug showed efficient uncaging yield, demonstrating the viability of using thioether as a radiation-sensitive group. Ionizing radiation ; Chemistry ; Environmental chemistry ; Toxicology ; Biology ; Irradiation ; Physics Free Radicals and Antioxidants
Authors: Odai Nassar
Source: Proceedings of the Royal Society A Mathematical Physical and Engineering Sciences (article, 2025-02-01)
Field: Materials Science — Materials Chemistry

On the conversion of plastic work into heat in metals This paper provides a comprehensive review of the methodologies employed to determine the fraction of plastic work converted into heat in the deformation of metals, known as the Taylor–Quinney coefficient (TQC). This review delves into the experimental, analytical and numerical methods found in the existing literature, highlighting their respective advantages and shortcomings, and reveals a notable variation in the reported values of the TQC of metals and how these values change with strain, strain rate, loading mode and microstructure. Despite this variation, the practice of considering the TQC as a constant between 0.85 and 0.95 is still found in the literature. The review identifies critical research gaps, emphasizing the scarcity of studies investigating the TQC at extremely high strains and strain rates. In addition, the paper highlights the interchangeability of using an integral and differential TQC without clear distinctions and the absence of objective conclusions supported by statistical significance. Work (physics) ; Materials science ; Mechanical engineering ; Engineering High-Velocity Impact and Material Behavior ; Advanced materials and composites ; Tunneling and Rock Mechanics
Authors: Luis Salvatella
Source: Journal of Chemical Education (article, 2025-10-28)
Field: Chemistry — Inorganic Chemistry

Rethinking Organic Chemistry: The Dual Electronic Behavior of the Alkyl Group A unified framework for understanding the electronic nature of alkyl substituents is presented, resolving the contradiction between spectroscopic data and reactivity patterns typically found in organic chemistry textbooks. This framework is based on the distinct interactions of alkyl groups with σ frameworks and π systems. When attached to an sp3-hybridized atom, as in alkanes, amines, and ethers, the alkyl group acts as an inductive electron-withdrawing substituent (relative to hydrogen). This behavior reflects the greater electronegativity of carbon than hydrogen, as evidenced by NMR chemical shifts and dipole moments. The stability trends observed for aliphatic carbanions and free radicals (ethyl < isopropyl < tert-butyl in both cases) are due to this electron-withdrawing character. The acidity trend of alcohols in aqueous mixtures (methanol > ethanol > 2-propanol > tert-butanol) correlates with the decreasing permittivities of the pure alcohols. Apparent electron-donating effects inferred from Gibbs free energy acidities of ammonium ions and substituted acetic acids arise from entropic artifacts caused by hydrophobic effects. When the alkyl group is bonded to an sp2-hybridized atom, as in alkenes, arenes, carbonyl compounds, carboxylic acids, amides, heterocycles, and carbocations, or to an sp-hybridized atom, as in alkynes, concurrent hyperconjugative electron donation occurs, which overcomes the inductive electron-withdrawing effect in the tert-butyl cation. This work calls for revising textbooks to emphasize both electronic effects and to replace the misinterpreted reactivity examples with spectroscopically validated models, thereby providing a consistent framework essential for educating students and training AI systems in chemistry. Electronegativity ; Alkyl ; Reactivity (psychology) ; Substituent ; Isopropyl ; Inductive effect ; Gibbs free energy ; Electronic effect ; Intramolecular force Synthesis and characterization of novel inorganic/organometallic compounds ; Radical Photochemical Reactions ; Molecular Junctions and Nanostructures
Authors: Michael Navin | Ramakrishnan Thirumalaisamy | D. Balaji | V. Bhuvaneswari
Source: Polymers (article, 2025-06-27)
Field: Materials Science — Polymers and Plastics

CRITIC–EDAS Approach for Evaluating Mechanical Properties of Flax/Vetiver/MFF Hybrid Composites This study investigates the mechanical properties and optimization of hybrid composites composed of flax, vetiver, and mahogany fruit fillers (MFFs) using epoxy resin as the matrix material. Nine distinct composite configurations were fabricated using different MFF concentrations (0, 5, and 10 wt.%) to evaluate their influence on tensile strength, flexural strength, and impact resistance. The MFF was subjected to alkali treatment and characterized using FTIR, XRD, and particle size analysis to enhance its compatibility with the polymer matrix. Vetiver and flax fibers also underwent alkali treatment to improve interfacial bonding. The composite fabrication process followed the Taguchi L9 orthogonal array to optimize the design. Mechanical testing revealed that the incorporation of MFF significantly improved the overall performance, with FVM9 (10 wt.% MFF) exhibiting the highest tensile strength (56.32 MPa), flexural strength (89.65 MPa), and impact resistance (10.46 kJ/m<sup>2</sup>). The CRITIC-EDAS method was employed to rank the composite configurations, and FVM9 was identified as the optimal configuration. Comparisons with alternative MCDM methods (WASPAS, COPRAS, TOPSIS, and VIKOR) validated the reliability of the rankings, and FVM9 consistently performed the best. The sensitivity analysis demonstrated the robustness of the CRITIC-EDAS approach, as the rankings remained stable despite variations in the criterion weights. The synergistic effect of flax, vetiver, and MFF, along with improved interfacial bonding, contributed to the superior mechanical properties of the hybrid composites. These findings highlight the potential of FVM composites as sustainable, high-performance materials for various industrial applications in the automotive, construction, and aerospace sectors. Materials science ; Composite material ; Ultimate tensile strength ; Flexural strength ; Composite number ; Epoxy ; Izod impact strength test ; Taguchi methods ; Compatibility (geochemistry) ; Orthogonal array Natural Fiber Reinforced Composites ; Mechanical Engineering and Vibrations Research ; Nanocomposite Films for Food Packaging
Authors: el-Kazzaz Sa | Angelo Oliveira Silva | Rita de Cássia Siqueira Curto Valle | Cintia Marangoni | Ariovaldo Bolzan | Ricardo Antônio Francisco Machado
Source: Chemical Engineering & Technology (article, 2025-05-05)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Optimal Conditions Linked to the Reducing Agent on the Role of Morphology of Silver Nanoparticles Abstract This study optimizes silver nanoparticle synthesis using response surface methodology to predict particle size diameter. Factors including agitation frequency, flow, temperature, reducing agent concentration, and heating time were varied using citrate and borohydride separately. Particle size was measured via dynamic light scattering and morphology analyzed by transmission electron microscope. Regardless of the reducing agent, concentration most significantly influenced particle size. Interactions were also crucial. Sodium borohydride synthesis yielded small, narrowly distributed nanoparticles across various size ranges. The study demonstrates the production of nanometric particles suitable for diverse technological applications. Morphology (biology) ; Nanoparticle ; Reducing agent ; Nanotechnology ; Silver nanoparticle ; Chemical engineering ; Chemistry ; Materials science ; Engineering ; Biology Gold and Silver Nanoparticles Synthesis and Applications ; Nanoparticles: synthesis and applications ; Laser-Ablation Synthesis of Nanoparticles
Authors: Mequanint Yilak Kassa | Samuel Tesfaye Mekonone | Tesfa Guadie Ayaliew | Robinson Gnanadurai Rengiah | Leul Fenta Demisie
Source: Discover Applied Sciences (article, 2025-10-02)
Field: Materials Science — Polymers and Plastics

Optimization of process parameters for sisal fiber-reinforced cornstarch biocomposites in sustainable packaging applications The disposal of plastic waste is a significant eco-technological issue that addresses global environmental degradation and climate change and produces poisonous byproducts that contribute to global pollution. Ethiopia is reporting an increasing number of problems related to the growing use of plastics and their disposal, which has increased the demand for biodegradable polymers. The objective of this study was to optimize the process parameters of sisal fiber-reinforced thermoplastic starch biocomposites for sustainable packaging applications. This study examined the effects of alkaline treatment (6% wt, 12% wt, and 18% wt) and fiber content (10% wt, 20% wt, and 30% wt) on the tensile strength, water absorption, and biodegradability of biocomposites. The composite sample test was prepared according to ASTM D638 for tensile strength, which is crucial for packaging materials as it determines their ability to withstand forces during handling, storage, and transportation; ASTM D570 for water absorption, which can degrade material properties and compromise package durability; and ASTM D5338 for the biodegradability test, which is a key feature for eco-friendly packaging materials, especially in response to environmental concerns regarding plastic waste. The combination of process parameters that optimizes tensile strength, water absorption and biodegradability simultaneously was obtained using Taguchi-based grey relational analysis. The results demonstrated that a biocomposite with optimal properties was fabricated with 30% wt fiber content and 18% wt alkali treatment. The biocomposite fabricated at the optimal process parameters achieved better water absorption, biodegradability, and tensile strength values of 40.22% wt, 64.78% wt, and 4.24 MPa, respectively. These results represent the best properties for intended sustainable packaging applications. Biocomposite ; Ultimate tensile strength ; SISAL ; Biodegradation ; Thermoplastic ; Absorption of water ; Environmentally friendly ; Fiber Natural Fiber Reinforced Composites ; Nanocomposite Films for Food Packaging ; Advanced Cellulose Research Studies
Authors: Marta Stefańska | Thomas Müntener | Sebastian Hiller
Source: Communications Chemistry (article, 2025-08-01)
Field: Chemistry — Spectroscopy

Photo-CIDNP for quantification of micromolar analytes in urine Towards target diagnostics of low-concentrated molecules in biofluids, NMR spectroscopy faces limitations due to low sensitivity, signal overlap, and high equipment costs. Hyperpolarization methods such as photo-chemically induced dynamic nuclear polarization (photo-CIDNP) can mitigate some of these challenges. In this study, we explore the potential of steady-state photo-CIDNP to quantify target molecules in urine samples. Matrix interference poses a significant challenge to quantitative measurements, and we thus establish two counteracting methods: spiking and biofluid dilution. Experiments conducted in both high (14.1 T) and low (1.9 T) magnetic fields demonstrate the effectiveness of photo-CIDNP-based quantification at micromolar levels for the analytes sumatriptan and paracetamol. We report limits of quantification (LOQs) in complex matrices down to 3.5 μM and average errors of less than 26% with the spiking method and less than 11% using biofluid dilution. This proof-of-concept study highlights the potential of NMR supported by photo-CIDNP as a target diagnostic tool for rapid drug quantification and clinical monitoring applications, especially with low-cost benchtop NMR devices. CIDNP ; Analyte ; Chromatography ; Chemistry ; Urine ; Biochemistry Advanced NMR Techniques and Applications ; Atomic and Subatomic Physics Research ; Electron Spin Resonance Studies
Authors: Jie Zhao | Zhenya Meng
Source: Research Square (preprint, 2025-05-30)
Field: Materials Science — Electronic, Optical and Magnetic Materials

High-sensitivity refractive index sensing based on a dual ultra- narrowband terahertz metasurface absorber Terahertz radiation ; Narrowband ; Refractive index ; Sensitivity (control systems) ; Materials science ; Terahertz metamaterials ; Optoelectronics ; Optics ; Index (typography) ; High-refractive-index polymer ; Physics ; Computer science ; Electronic engineering ; Engineering ; Far-infrared laser Metamaterials and Metasurfaces Applications ; Advanced Antenna and Metasurface Technologies ; Antenna Design and Analysis