Search Results (2,719)

Molecular dynamics simulations were used to study the interaction of Ar clusters with silicon and germanium single crystals at a fixed cluster size of 923 atoms and a total kinetic energy of 10 keV. A comparative analysis was conducted to examine the effects of argon cluster impacts on the surface morphology of silicon and germanium as the cluster incidence angle varied from 0° to 75° with respect to the surface normal. The depth of amorphization and the height of hillocks induced in silicon and germanium after argon cluster bombardment were estimated. Angular dependences of the crater diameters along and perpendicular to the cluster incidence direction were demonstrated. Comparisons of crater characteristics and the ratios of longitudinal to transverse crater dimensions revealed material-specific features of cluster–surface interactions. At oblique incidence, a peak in the ratio of displaced atoms in the amorphous layer to those above the surface was observed. The potential energy of silicon and germanium target atoms following cluster impact was visualized and estimated. Moreover, the redistribution patterns of the cluster’s initial kinetic energy among the target, scattered cluster atoms, and sputtered target atoms were compared for silicon and germanium at incidence angles from 0° to 75°. Full article

Apple pomace represents an important agro-industrial residue with high moisture content and significant environmental burden if improperly managed. This study investigated its thermochemical valorisation into biochar via two processes, followed by comprehensive physicochemical characterization and agronomic evaluation. Elemental analysis revealed carbon enrichment from 47.89% in raw material to 77–78% after the thermal process, evidencing a progressive aromatization. Scanning electron microscopy, Fourier transform infrared spectroscopy, and Raman analysis confirmed a temperature-dependent transition from partially amorphous carbon (400 °C) to more ordered aromatic structures (450 °C), while excessive thermal treatment (550 °C) increased structural defects. ICP-OES revealed an enrichment in thermally stable metals (Fe, Al, Mn) and limited Cd accumulation. Germination assays using Triticum aestivum L. demonstrated that biochar produced at 400 °C significantly improved the germination uniformity and seedling height (14.1 mm), as well as biomass accumulation compared to the control soil sample. The fertilizer addition increased the soluble Na and electrical conductivity (up to 643 µS/cm), potentially inducing transient salinity stress. Soil chemical analysis indicated increased K availability in soils amended with biochar produced at 400 °C, whereas the combination of biochar obtained at 450 °C with fertilizer conducted to elevated concentrations of certain trace metals, mainly Ni and Cr, highlighting the demand for careful monitoring. Overall, the biochar produced at 400 °C yielded to an optimal balance between structural stability, nutrient enrichment, and agronomic performance, evidencing that apple pomace may be a viable feedstock for sustainable biochar production within circular bioeconomy frameworks. Full article

The sustainable management of olive wastes represents an important environmental challenge. Biochars and hydrochars derived from biomass are promising adsorbents for removing emerging pollutants from water. In the present work, olive stone wastes were converted into biochar and hydrochar by using pyrolysis (500 °C for 30 min) and hydrothermal carbonization (HTC) processes (220 °C for 10 h). Then, the obtained materials were physically activated by using CO₂ gas (750 °C for 30, 60 and 180 min). Various analytical techniques were applied for the chemical, textural and structural characterization of these carbonaceous materials (i.e., ultimate and proximate analysis, scanning electron microscopy (SEM), BET surface area, Raman spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy). Afterwards, the selected activated biochar and hydrochar were applied for the removal of amoxicillin from aqueous solutions. The experimental results show that the generated hydrochar has many microspheres on its surface and inside, while the produced biochar exhibits a porous structure with irregular forms. CO₂ physical activation has induced an important improvement of the biochar and hydrochar’s structural, textural, and surface chemistry properties. For instance, the activated biochar samples show a highly porous structure, with large specific surface areas that increase with the burn-off, reaching 1349.3 m² g⁻¹ following 3 h of activation. Regarding the activated hydrochar samples, they exhibit a spherical morphological structure with an important specific surface area, which increased to 846.7 m² g⁻¹ after 3 h of activation. Moreover, both activated materials have an amorphous structure with low oxygen surface groups. The selected novel CO₂-activated biochar and hydrochar efficiently remove amoxicillin from aqueous solutions under wide experimental conditions, with adsorption capacities of 386.4 and 215.9 mg g⁻¹, respectively. These efficiencies are higher than those reported for various activated biochars derived from lignocellulosic biomass, from sewage sludge, and from animal manure. Future research works are required to assess these materials’ effectiveness in treating real pharmaceutical effluents, to optimize the regeneration of the amoxicillin-loaded materials, and to design full-scale devices for a real application. Full article

A comparative study on the effects of mechanical treatment by high-energy ball milling on talc (2:1 layered silicate) and kaolinite (1:1 layer silicate) was performed. Industrial samples of talc and kaolin were characterized by XRF, thermal analysis (DTA and TG), and XRD methods. The XRD analysis evidenced the destruction of the crystalline structures of both talc and kaolinite and accessory minerals in the samples, showing an increase in the amorphous phases and a progressive change to a more disordered structure. It was found that high-energy ball milling resulted in a reduction of 48% of talc at 4 h of grinding, and the reduction increased up to ~80% at 32 h. The mechanical treatment produced a decrease in initial kaolinite content by 25% after 4 h of grinding and a reduction of ~70% after 32 h. It was deduced by this analysis that the structure of kaolinite is more difficult to destroy by high-energy ball milling than the structure of talc under the same experimental milling conditions. The structural alterations in talc and kaolinite were anisotropic, with crystal degradation along [00l], and there was a progressive loss of long-range order; moreover, the crystal dimensions following the c-axis direction became too small to produce coherent diffraction. A decrease in crystal size (coherent diffraction microdomain) was observed by the mechanical treatment, with an increase in microstrains produced by high-energy ball milling. Thus, the crystal size decreased from 280 to 200 Å in talc (direction perpendicular to 002) and from 250 to 210 Å in kaolinite (direction perpendicular to 001) after 16 h of grinding, with an important reduction in crystal size up to a value of 138 Å but only in the case of kaolinite at 80 h of grinding, with talc completely amorphous to X-rays at the same grinding time. Microstrains followed an inverse evolution compared to the crystal size, with an increase in the values obtained by progressive grinding in both talc and kaolinite. The values of microstrains were found to be of the same order for talc and kaolinite, although they were relatively higher for talc since it is associated with a greater degree of structural alteration than kaolinite. The XRD results showed an inverse correlation between both parameters, with their relative values being higher for talc compared with kaolinite. The present study is of basic interest for further investigations into the effects of high-energy ball milling using talc and kaolin as raw materials with reduced particle size, for instance, in the ceramic and paper industries. Full article

The self-directed channel (SDC) class of memristors employs a multilayer architecture that is designed to enable robust Ag ion conduction, long cycling lifetime, and thermal stability. While several layers contribute to mechanical and chemical reliability, two layers primarily govern the electrical behavior: the amorphous Ge–chalcogenide active layer that is adjacent to the bottom electrode and the overlying metal–chalcogenide source layer. In this work, we investigate how the variation in the chalcogen species in these two layers influences switching characteristics in the pre-write regime, both in the pristine state and after a write/erase cycle, as well as the conduction behavior at room temperature. The devices were fabricated using Ge-rich chalcogenides containing O, S, Se, or Te, combined with SnS, SnSe, or Ag₂Se metal–chalcogenide layers. The DC current-voltage measurements were analyzed using the standard linearization approaches to examine whether the transport behavior in the pre-write regime exhibits characteristics that are associated with Ohmic, Schottky, Poole–Frenkel, or space charge limited conduction. These measurements specifically probe the pre-write region of the I-V curve, where early ionic redistribution and structural rearrangement precede the abrupt formation of the conductive channels responsible for the resistive switching. The results show that the chalcogen composition strongly affects the threshold voltage, the resistance window, and the onset of field-enhanced transport, reflecting the differences in ionic distribution and channel formation dynamics. The results indicate that transport evolves with a bias and a compliance current, transitioning between regimes that are influenced by the interface injection and bulk-limited conduction, depending on the material stack. These findings clarify the role of chalcogen chemistry in governing the SDC switching behavior and provide guidance for the material selection in application-specific device design. Full article

Recycled concrete powder (RCP) utilization as an auxiliary cementitious material absorbs construction waste and promotes low-carbon transition in construction by replacing high-carbon materials. This study optimized RCP’s particle size and amorphous SiO₂ content through physical activation, systematically investigating its effects on alkali-activated cementitious materials (AACMs). The results demonstrated that 20% activated RCP enhanced compressive strength by 9% (34.2 MPa), only 12.7% lower than that of the reference samples. Hydration analysis revealed activated RCP delayed exothermic peaks but increased total heat via active particles. Life-cycle assessment showed substituting 20% ground granulated blast-furnace slag (GGBS)/fly ash (FA) with RCP reduced carbon emissions from 169.3 to 165.9 kg CO₂-e/ton (−2.1%). Although activation slightly raised emissions to 166.6 kg CO₂-e/ton, RCP’s carbon contribution remained at 9% versus GGBS’s 83% dominance. Crucially, the activation’s 0.7 kg CO₂-e/ton increase was offset by 4.7 kg CO₂-e/ton reductions from material substitution and waste recycling benefits, confirming its net carbon-neutral potential. Full article

Biofouling has a detrimental effect on marine infrastructure and poses a severe challenge to the global marine industry. Therefore, developing efficient and environmentally friendly anti-fouling coatings to protect those facilities has become extremely necessary nowadays. To address marine biofouling, a series of photocurable degradable waterborne boron-containing polyurethane acrylate (WPU-PTPBx) anti-fouling coatings were prepared by grafting pyridine-triphenylborane (PTPB) onto polyurethane side chains and UV curing. FTIR and ¹H NMR confirmed the successful grafting of PTPB. The WPU-PTPBx aqueous dispersions had a particle size of 30~75 nm with excellent thermal storage stability. DSC and XRD characterizations revealed the amorphous structure of the coatings, which favored biodegradation. All coatings exhibited adhesion strength over 2 MPa, meeting marine application requirements. Antibacterial and anti-algal tests showed that PTPB content positively correlated with anti-fouling performance: the coating achieved a 99.66% inhibition rate against Escherichia coli and reduced the adhesion density of Nitzschia closterium to only 36.9 cells/mm². With favorable degradability and outstanding anti-fouling performance, WPU-PTPBx coatings are promising green anti-fouling materials for marine applications. Full article

In this work, a hybrid polymer electrolyte integrating single- and dual-ion conducting systems was developed for lithium-ion batteries using bio-based materials, namely oleic-acid derivatives and epoxidized soybean oil, through an in situ polymerization process. The fixed FSI anions in LiEFSOA enhance the selectivity of Li⁺ transport, while the cross-linked network formed by ESO provides mechanical stability, and the LiFSI incorporated into the polymer matrix helps maintain sufficient overall ionic conductivity. In addition, the long C18 oleic chains increase the internal free volume of the matrix, thereby improving segmental mobility within the amorphous phase. The in situ polymerization inside the cell causes intimate interfacial contact between the electrode and electrolyte, achieving an ionic conductivity of 1.05 × 10⁻⁴ S cm⁻¹ at 30 °C. Electrochemical evaluation using LiFePO₄/FSOA-2/Li cells shows an initial discharge capacity of 149.09 mAh g⁻¹ and a capacity retention of 81.09% after 100 cycles, and the average coulombic efficiency was 99.62%, demonstrating that the designed FSOA electrolyte exhibits stable cycling performance and competitive capacity. Overall, the combination of eco-friendly materials and a hybrid ion transport strategy provides a promising platform for developing sustainable and high-performance polymer electrolytes for lithium-ion batteries. Full article

The conducted study was focused on the development of a new type of polymer blends intended for additive manufacturing applications, in particular, the material extrusion method (MEX). The developed materials were prepared from recycled poly(ethylene terephthalate) and amorphous copolymers poly(ethylene terephthalate-glycol) (PETG), and poly(cyclohexylenedimethyl terephthalate-glycol) (PCTG). The basic blend systems were additionally modified with POE-g-GMA impact modifier (IM) during the reactive extrusion process. The main aim of the work was to assess the effectiveness of using composite additives and their influence on the mechanical and thermomechanical parameters of the tested systems. To prepare the composites, selected polymer blends were modified with 10% of talc (T) and carbon fibers (CF). The properties evaluation includes the mechanical/thermomechanical testing, thermal analysis and structural observations. The accuracy of printing was measured using optical scanning methods. The test results indicate that even the relatively small amount of the CF filler could lead to a significant increase in tensile modulus from reference 1.6 GPa to 2.9 GPa; the same improvement applies to strength values, where the CF-modified materials reached 45 MPa, compared to the reference 31 MPa. The heat deflection tests (0.455 MPa) after annealing revealed the maximum HDT of around 170 °C for both types of CF-modified materials. The Vicat test results were also favorable for annealed materials. Considering that the Vicat/HDT results after the 3D-printing process usually reach around 70 °C, the performed heat treatment strongly enhanced the heat resistance for most of the prepared blends. The performed studies revealed that for most of the prepared materials, the brittleness was a common drawback for both MEX-printed and injection-molded materials. Full article

Nickel-oxide-based anodic electrochromic materials are extensively utilized as counter electrodes in smart window systems due to their reversible optical response during ion insertion and extraction. This study systematically investigates the influence of substrate temperature on the electrochromic properties of sputtered nickel-tungsten oxide thin films. The deposited thin films exhibit an amorphous structure. An increase in substrate temperature results in a decrease in nickel-vacancy concentration. Raman spectroscopy verifies the amorphous nature. Films deposited at lower substrate temperatures exhibit superior electrochromic performance, characterized by improved optical contrast of 64% and rapid coloration (2.21 s) and bleaching (0.93 s) dynamics. The enhanced performance is ascribed to the disordered amorphous structure and the existence of enough nickel vacancies, which collectively facilitate efficient and reversible lithium-ion transfer. This study illustrates that meticulous regulation of substrate temperature is an effective method for adjusting the microstructure and defect chemistry of nickel–tungsten oxide thin films, rendering them appropriate as effective counter electrodes for energy-efficient smart window applications. Full article

In this study, rice-husk fiber (RHF) extracted via alkali hydrolysis was used as a reinforcing material (0–10 wt%) in a pectin-sodium alginate (PE/SA) matrix to develop biofilms by the casting method. These biofilms were characterized by using FTIR, XRD, TGA, and DSC. The thickness, moisture content, water solubility, swelling behavior, water-contact angle, water-vapor permeability, optical transparency, and mechanical properties of biofilms were investigated. It was observed that the PE/SA/RHF film loaded with 5% RHF had better visual attributes, and a further increase in reinforcement was not found to be as favorable. The addition of 10 wt% RHF significantly enhanced the thickness from 0.094 to 0.127 mm, water solubility from 49.25 to 56.13%, water-contact angle from 48.4 to 62.6°, and tensile strength from 4.17 to 10.23 MPa. However, decreases in water-vapor permeability from 1.94 × 10⁻⁹ to 1.32 × 10⁻⁹ g·m⁻¹·Pa⁻¹·s⁻¹ and in elongation at break from 19.24 to 2.87% were observed in the biofilms. Structurally, FTIR confirmed intermolecular hydrogen bonding between components. XRD revealed that the films remained predominantly amorphous, without significant crystalline alterations. Furthermore, thermal stability improved with the addition of RHF. Finally, these PE/SA/RHF composite films may be potential eco-friendly biodegradable packaging candidates for food industry applications. Full article

The commercialization of poly(butylene succinate-co-adipate) (PBSA), a biodegradable and potentially fully biobased random copolyester, is still ongoing. Due to its high relevance as mono material or as blend component in flexible film applications, a sound understanding of compounding, further processing and film properties is necessary. In this work, PBSA, poly (lactic acid) (PLA) and blends at three different compositions thereof were processed into flat films and blown films, respectively. Investigating the films with X-ray diffraction (XRD), multivariate confocal Raman microscopy (CRM) and scanning electron microscopy (SEM) revealed the semicrystalline order as well as the blend morphology. While PBSA is semicrystalline, PLA remains amorphous after the processing step. As imaged by CRM, flat films exhibit lamellar-like domains formed during uniaxial stretching and rapid cooling, whereas blown films show no pronounced preferential orientation. Tensile tests in both the machine and transverse directions demonstrate the versatility of PBSA and its blends in spanning a wide range of mechanical strength and flexibility, covering and partly exceeding the stiffness and strength ranges typically reported for commodity polyolefins while exhibiting reduced ductility. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) provide further insights into the thermal properties of the pure and blend materials. Full article

The modification of road bitumen using micro-sized carbonaceous materials offers a promising route to enhance pavement performance; however, the influence of microdispersed coke derived from coal and petroleum sources has not been sufficiently clarified. In this study, coal and petroleum coke from Pavlodar Petrochemical Plant LLC (Pavlodar, Kazakhstan) were mechanochemically activated and used as the modifiers for BND 100/130 bitumen, produced by Asphaltbeton 1 LLC (Almaty, Kazakhstan). X-ray diffraction and scanning electron microscopy were used to determine the structure and morphology of the resulting coke powders. Standard tests and the Superpave Multiple Stress Creep and Recovery (MSCR) methodology were used to determine the physico-mechanical and rheological properties of the modified binders. Microdispersed granular coke powders produced after mechanochemical activation had a minimum average particle diameter of 8.28 µm (petroleum coke) and 16.64 µm (coal coke), and were mainly an amorphous carbon phase with traces of graphite. Addition of 1 wt.% microdispersed coke resulted in better performance of binder and an enhancement in grades of BND 100/130 to BND 70/100, in line with ST RK 1373-2013. MSCR testing showed that Jnr_3.2 is between 2.0–3.0 kPa⁻¹, which is in the S category of AASHTO M 332-20. This study showed how micro-sized coal and petroleum coke can be effectively used as a high-carbon modifier in bitumen, which reflects the possibility of their practical use in asphalt pavements that are subjected to normal traffic conditions. Full article

Rising atmospheric CO₂ levels have increased the demand for robust, scalable adsorbents for practical CO₂ capture and separation. Porous organic polymers (POPs) are attractive candidates because their pore architecture and binding site properties can be precisely tuned via building blocks and linkage formation. This review summarizes experimental and computational studies of azo-linked POPs and, more broadly, nitrogen–nitrogen (N–N) linked systems, emphasizing how synthetic routes, building blocks, and framework topology govern CO₂ uptake. We highlight key synthetic strategies and representative systems, including porphyrin–azo networks, and discuss the relatively sparse experimental literature on alternative N–N linked POPs incorporating azoxy and azodioxy motifs. Emphasis is placed on reversible nitroso/azodioxide chemistry as a potential pathway to ordered porous organic materials. Computational studies provide a practical route to connect structure with adsorption behavior in largely amorphous or partially ordered networks. We review hierarchical workflows combining periodic DFT and electrostatic potential properties, grand canonical Monte Carlo (GCMC) simulations, and binding energy calculations to rationalize trends and identify favorable binding environments. Computational findings demonstrate that pore accessibility and stacking models can strongly influence predicted CO₂ adsorption. This review provides guidelines for designing POPs with enhanced CO₂ adsorption, offering an outlook and discussing challenges for future studies. Full article

Brittle materials such as single crystals, polycrystalline ceramics, and amorphous glass are indispensable in modern industry. Driven by improvements in equipment performance, the required fabrication precision for optical elements and devices has reached nanoscale and is steadily advancing toward atomic level. Despite their outstanding physical and chemical properties, fabricating a defect-free surface with nanometer-level roughness on brittle materials is challenging due to microcracking, brittle fracture and severe tool wear. In recent years, field-assisted cutting has emerged to overcome the bottleneck in ultra-precision cutting of brittle materials. This review summarizes investigations of material removal mechanisms of brittle materials in ultra-precision cutting and surveys representative field-assisted cutting technologies—including laser, vibration, magnetic field, and ion implantation assisted cutting—highlighting how these fields broaden ductile-regime machining and suppress the machining-induced defects. This review further discusses the emerging multi-field coupling strategies and outlines future research directions in machining mechanisms to enable high-efficiency, low-damage, and high-consistency manufacturing of brittle materials. Full article