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Ionic transport inside porous carbon electrodes underpins the storage of energy in supercapacitors and the rate at which they can charge and discharge, yet few studies have elucidated the materials properties that influence ion dynamics. Here we use in situ pulsed field gradient NMR spectroscopy to measure ionic diffusion in supercapacitors directly. We find that confinement in the nanoporous electrode structures decreases the effective self-diffusion coefficients of ions by over two orders of magnitude compared with neat electrolyte, and in-pore diffusion is modulated by changes in ion populations at the electrode/electrolyte interface during charging. Electrolyte concentration and carbon pore size distributions also affect in-pore diffusion and the movement of ions in and out of the nanopores. In light of our findings we propose that controlling the charging mechanism may allow the tuning of the energy and power performances of supercapacitors for a range of different applications. It is challenging to probe ion dynamics in supercapacitor electrodes, which has significant implications in optimizing their performance. Here, the authors develop in situ diffusion NMR spectroscopy to measure and illustrate the diffusion of the charge-storing ions in working supercapacitors.

Graphene and single-walled carbon nanotubes are carbon materials that exhibit excellent electrical conductivities and large specific surface areas. Theoretical work suggested that a covalently bonded graphene/single-walled carbon nanotube hybrid material would extend those properties to three dimensions, and be useful in energy storage and nanoelectronic technologies. Here we disclose a method to bond graphene and single-walled carbon nanotubes seamlessly during the growth stage. The hybrid material exhibits a surface area >2,000 m 2  g −1 with ohmic contact from the vertically aligned single-walled carbon nanotubes to the graphene. Using aberration-corrected scanning transmission electron microscopy, we observed the covalent transformation of sp 2 carbon between the planar graphene and the single-walled carbon nanotubes at the atomic resolution level. These findings provide a new benchmark for understanding the three-dimensional graphene/single-walled carbon nanotube-conjoined materials. Graphene and single-walled carbon nanotubes have high electrical conductivities and large specific surface areas. Here, these properties are extended into three dimensions by producing a seamless carbon nanotube graphene hybrid material.

Coal is the most abundant and readily combustible energy resource being used worldwide. However, its structural characteristic creates a perception that coal is only useful for producing energy via burning. Here we report a facile approach to synthesize tunable graphene quantum dots from various types of coal, and establish that the unique coal structure has an advantage over pure sp 2 -carbon allotropes for producing quantum dots. The crystalline carbon within the coal structure is easier to oxidatively displace than when pure sp 2 -carbon structures are used, resulting in nanometre-sized graphene quantum dots with amorphous carbon addends on the edges. The synthesized graphene quantum dots, produced in up to 20% isolated yield from coal, are soluble and fluorescent in aqueous solution, providing promise for applications in areas such as bioimaging, biomedicine, photovoltaics and optoelectronics, in addition to being inexpensive additives for structural composites. Coal is widely used for energy generation, but has not been considered for possible functional materials. Here, the authors report the one-step formation of graphene quantum dots from coal at yields of up to 20%, which is advantageous when compared with their syntheses from sp 2 -type carbon structures.

This study assesses the feasibility of using Colloidal Nano-Silica (CNS) as a modifier for the radioactive waste immobilization matrix by investigating its effects on the setting time, soundness, mechanical stability, microstructure evolution, and solidification mechanism in simplified cementitious systems. It provides highlights into the isolated role of the CNS in the evolution of the solidification process, analyzes the temporal sensitivity of the mechanical strength evolution and its dependency on the CNS dosage, and provides mechanistic insights into the role of CNS in the changes in the controlling hydration reaction. In this respect, the nano-silica was synthesized via the sol–gel method and extensively characterized to determine its physicochemical properties. The resulting amorphous material, with a particle size below 2.49 nm and approximately 20 wt.% of weakly bound and chemically adsorbed water, forms a stable colloidal solution with a zeta potential of -33.9 mV. Incorporating CNS into cementitious matrices notably altered hydration kinetics, mechanical performance. and improves the durability. CNS accelerated both initial and final setting, exhibiting a non-monotonic trend as a function of CNS content, attributed to its water adsorption capacity, most pronounced at 5 wt.%. All formulations maintained acceptable soundness, with optimal enhancement observed at 3 wt.%, beyond which minor deterioration was detected at 5 wt.%. Although compressive strength generally declined with CNS addition over the curing period, the values remained above the minimum threshold for use in radioactive waste backfilling and waste immobilization. Mathematical analysis of the behavior over a 45-day curing period revealed that compressive strength was relatively insensitive to CNS variation, particularly between 1.5% and 3% material incooperation. Temporal analysis further indicated that strength development was limited during early curing stages but became material-specific at later ages. The improved durability of the 3% CNS-supplemented materials is related to the lime-silica reaction and the formation of C-S–H of low ca/si ratio. Mechanistic insights suggest that CNS addition promotes nucleation and growth mechanisms at the expense of diffusion-driven hydration, with critical transitions observed at 3% and 5% CNS content.

Background Therapeutic quality of endodontic sealers plays a critical role in promoting the success of root canal therapy by blocking entrance of microbes as well as facilitating tissue reparative process. The bioceramic sealers NeoSEALER Flo and CeraSeal have been on the rise owing to their biocompatibility and bioactivity. However, their relations with periapical tissues especially human gingival fibroblasts (HGFs) are still significant determinants of treatment outcomes. This in vitro case intends to analyze the inflammatory reaction of HGFs towards NeoSEALER Flo and CeraSeal bioceramic sealers and AH plus resin sealer as control. Materials and methods HGFs were cultured and treated with eluates of tested sealers at different dilutions; 25%, 50%, 75% and 100%. The extracts were left in incubator for 1, 3, and 7 days. Cell death was determined by the MTT assay, and the secretion levels of pro-inflammatory cytokines such as IL-6, IL-8, and TNF-α, were measured using q RT-PCR. Furthermore, mRNA and protein levels of some inflammatory markers were also estimated by q RT-PCR. Results Analysis of the data showed that NeoSEALER Flo was cytotoxic in a concentration-dependent manner to HGFs, though it appeared marginally more toxic than CeraSeal when tested at the same ratios and same time. The high levels of all the measured pro-inflammatory cytokines in HGFs treated with both sealers at a higher concentration with NeoSEALER Flo showing a more intense effect. Having said so, gene expression profiles endorsed these results by showing that both sealers increase the level of IL-6, IL-8, and TNF-α at the higher concentrations. Conclusions The study indicates that both NeoSEALER Flo and CeraSeal bioceramic sealers activate HGFs inflammatory response with a slight preference for CeraSeal biocompatibility. Therefore, it becomes important and relevant to assess the cytotoxic and inflammatory propensity of various endodontic materials in order to guide enrolment of these endodontic products in clinical practice and improve the quality of endodontic treatment. Subsequent in vivo works should be done to confirm these in vitro findings as well as to examine the chronic effects of sealer-tissue interaction.

Nano-zeolite is an innovative class of materials that received recognition for its potential use in water and tertiary wastewater treatment. These applications include ion-exchange/sorption, photo-degradation, and membrane separation. The aim of this work is to summarize and analyze the current knowledge about the utilization of nano-zeolite in these applications, identify the gaps in this field, and highlight the challenges that face the wide scale applications of these materials. Within this context, an introduction to water quality, water and wastewater treatment, utilization of zeolite in contaminant removal from water was addressed and linked to its structure and the advances in zeolite preparation techniques were overviewed. To have insights into the trends of the scientific interest in this field, an in-depth analysis of the variation in annual research distribution over the last decade was performed for each application. This analysis covered the research that addressed the potential use of both zeolites and nano-zeolites. For each application, the characterization, experimental testing schemes, and theoretical analysis methodologies were overviewed. The results of the most advanced research were collected, summarized, and analyzed to allow an easy visualization and comparison of these research results. Finally, the gaps and challenges that face these applications are concluded.

The potential use of PVA-mixed-valent tunnel structured manganese oxide nano-composite in the removal of multi-contaminants form aqueous solutions was assessed by studying the continuous simultaneous removal of lead, caesium, and cobalt. Within this context, the morphology and the nature of nanoparticle inclusion into the PVA matrix was assessed using SEM–EDX analysis. The nanoparticles are homogenously distributed in the polymeric matrix with some agglomerated inclusions of these particles. The thermal and chemical stability analyses prove the stability of the material up to 180 °C and in slightly acidic to slightly alkaline solutions. The analysis of the gravimetric thermal data shows that the thermal treatment is a feasible end of life management route for this material. The values of percentage uptake and bed capacity indicate the feasibility of the use of this material in the simultaneous removal of lead, caesium and cobalt. The breakthrough curves analyses provide insights into the breakthrough characteristics and underlying removal mechanisms. It was found that the removal reaction follows Langmuir kinetics of adsorption–desorption and that the rate driving forces follow second order reversible reaction kinetics, where the sorption occur at energetically equal sites.

Technological applications of nuclear science and technology in different sectors have proved their reliabilities and sustainability over decades. These applications have supported various human civilization needs, ranging from power generation to industrial, medical, and environmental applications. Environmental applications of radiation sources are used to support decision making processes in many fields; including the detection and analysis of pollutant transport, water resources management, and treatment of municipal and industrial wastewaters. This work reviewed recent advances in the research and applications of ionizing radiation in treating different wastewater effluents. The main objective of the work is to highlight the role of ionizing radiation technology in the treatment of complex wastewater effluents generated from various human activities and to address its sustainability. Results of both laboratory and industrial scale applications of this treatment technology have been reviewed, and information on operational safety of industrial irradiators, which affect the sustainability of this technology, has been summarized.

This study aimed to evaluate the quality of Public Transport (PT) in the Jordan University of Science and Technology (JUST) area, Irbid, Jordan. The study focused on two different analytical techniques. The first was the Partial Least Squares Structural Equation Model (PLS-SEM) method to analyze student satisfaction and loyalty toward using PT. The second method was binary logistic regression (BLR), which analyzed factors such as socioeconomic status and travel habits that might make someone choose PT or their car to travel to JUST. Data were collected through an electronic and paper-based questionnaire with 572 participants. This study concluded that the proposed structural model could explain 76% of the loyalty variance. Passenger satisfaction, perceived service quality, perceived costs, and environmental impact were four of the five factors directly influencing passenger loyalty that demonstrated significant impact. In addition, it was concluded that through Multi-Group Analysis (MGA), gender group was the most influential categorical moderator variable. Moreover, the indirect analysis showed that perceived service quality was the most important mediator between the observed constructs’ relationships. BLR showed that the mode of transportation at JUST was statistically correlated with occupancy, travel cost, travel time, average use of PT, and car ownership, with an overall model accuracy of 90.0%. In conclusion, by considering the discussed influencing factors, it is recommended that transportation agencies consider perceived costs, information, reliability, safety, and vehicle characteristics variables while improving PT service quality and travel time, especially in rural areas, which may raise passenger satisfaction, shift car users to PT, and lower emissions. Thus, research results can assist policymakers in implementing sustainable modes of PT.

Critical thinking is one of the important abilities in learning mathematics, but the fact shows most high school students in Aceh have not developed the thinking skill yet. One of the causes is the mathematics learning that is carried out does not pay attention to critical thinking skills. This study aims to determine the increase in students’ critical thinking skills in linear programming learning through the Problem Based Learning (PBL) model assisted by GeoGebra Software in SMA Negeri 2 Teupah Barat. This research is a semi-experimental study with one group pre-test post-test design. The population in this study were all 24 students of class XI at SMA Negeri 2 Teupah Barat. A sample of 10 students was selected using the purposive sampling technique. The instrument used was the pre-test and post-test questions on critical thinking skills. The data were analyzed using SPSS 25 software including data description, normality test, paired sample t-test, and N-Gain score. The results showed that the use of the PBL model assisted by GeoGebra software can improve students’critical thinking skills on linear programming material at SMA Negeri 2 Teupah Barat with an average increase in students’ critical thinking skills of 50.05%, a minimum increase of 36.53% and a maximum increase of 63.57%.