콘크리트 도로포장의 보강재로 사용된 철근은 염해나 중성화 등으로 인하여 지속적인 손상이 발생하고 있으며, 이에 따른 유지관리 비용의 증대가 사회적 관심으로 대두되고 있다. 이를 해결하기 위하여 건설분야에서는 철근보다 내부식성 및 내알칼리성이 뛰어난 유 리섬유강화폴리머(Glass Fiber Reinforced Polymer, GFRP)가 사용되고 있다. 하지만, 수분 및 염해 등의 환경에 대한 내구성 검증은 충분히 이루어지지 않고 있는 실정이다. 따라서, 이 연구에서는 국내외에서 생산하는 직경 22mm GFRP 보강근을 ASTM D570에 의 거하여 흡수율 품질기준을 평가하였다. 흡수율 실험결과, 국내에서 생산된 GFRP의 경우 가장 높은 0.15% 수준의 흡수율을 나타내었으며, 해외에서 생산된 GFRP의 경우 0.03% 이내 수준의 흡수율을 나타내었다. 이는 KCI-GFRP 101 : 2024 및 ASTM D7957에서 제시하고 있는 GFRP 보강근 흡수율 품 질기준은 0.25% 이하를 모두 만족하는 것으로 분석되었다. 철근대체제로써 활용을 위해서는 장기침지 및 특수한 환경 등에 대한 내구 특성에 대한 추가적인 실험적 검토가 필요할 것으로 판단된다.

Plants synthesize antioxidant compounds as a defense mechanism against reactive oxygen species. Recently, plant-derived antioxidant compounds have attracted attention due to the increasing consumer awareness in the heath industry. However, traditional methods for measuring the antioxidant activity of these compounds are time-consuming and costly. Therefore, our study constructed a quantitative structure-activity relationship (QSAR) model that can predict antioxidant activity using graph convolutional networks (GCN) from plant structural data. The accuracy (Acc) of the model reached 0.6 and the loss reached 0.03. Although with lower accuracy than previously reported QSAR models, our model showed the possibility of predicting DPPH antioxidant activity in a wide range of plant compounds (phenolics, polyphenols, vitamins, etc.) based on their graph structure.

The optimization of deacetylation process parameters for producing chitosan from isolated chitin shrimp shell waste was investigated using response surface methodology with central composite design (RSM-CCD). Three independent variables viz, NaOH concentration (X1), radiation power (X2), and reaction time (X3) were examined to determine their respective effects on the degree of deacetylation (DD). The DD of chitosan was also calculated using the baseline approach of the Fourier Transform Infrared (FTIR) spectra of the yields. RSM-CCD analysis showed that the optimal chitosan DD value of 96.45 % was obtained at an optimized condition of 63.41 % (w/v) NaOH concentration, 227.28 W radiation power, and 3.34 min deacetylation reaction. The DD was strongly controlled by NaOH concentration, irradiation power, and reaction duration. The coefficients of correlation were 0.257, 0.680, and 0.390, respectively. Because the procedure used microwave radiation absorption, radiation power had a substantial correlation of 0.600~0.800 compared to the two low variables, which were 0.200~0.400. This independently predicted robust quadratic model interaction has been validated for predicting the DD of chitin.

Slipchip offers advantages such as high-throughout, low cost, and simple operation, and therefore, it is one of the technologies with the greatest potential for high-throughput, single-cell, and single-molecule analyses. Slipchip devices have achieved remarkable advances over the past decades, with its simplified molecular diagnostics gaining particular attention, especially during the COVID-19 pandemic and in various infectious diseases scenarios. Medical testing based on nucleic acid amplification in the Slipchip has become a promising alternative simple and rapid diagnostic tool in field situations. Herein, we present a comprehensive review of Slipchip device advances in molecular diagnostics, highlighting its use in digital recombinase polymerase amplification (RPA), loop-mediated isothermal amplification (LAMP), and polymerase chain reaction (PCR). Slipchip technology allows users to conduct reliable droplet transfers with high-throughput potential for single-cell and molecule analyses. This review explores the device’s versatility in miniaturized and rapid molecular diagnostics. A complete Slipchip device can be operated without special equipment or skilled handling, and provides high-throughput results in minimum settings. This review focuses on recent developments and Slipchip device challenges that need to be addressed for further advancements in microfluidics technology.

The Sun-Earth Lagrange point L4, which is called a parking space of space, is considered one of the unique places where solar activity and the heliospheric environment can be observed continuously and comprehensively. The L4 mission affords a clear and wide-angle view of the Sun-Earth line for the study of Sun-Earth connections from remote-sensing observations. The L4 mission will significantly contribute to advancing heliophysics science, improving space weather forecasting capability, extending space weather studies far beyond near-Earth space, and reducing risk from solar radiation hazards on human missions to the Moon and Mars. Our paper outlines the importance of L4 observations by using remote-sensing instruments and advocates comprehensive and coordinated observations of the heliosphere at multi-points including other planned L1 and L5 missions. We mainly discuss scientific perspectives on three topics in view of remote sensing observations: (1) solar magnetic field structure and evolution, (2) source regions of geoeffective solar energetic particles (SEPs), and (3) stereoscopic views of solar corona and coronal mass ejections (CMEs).

In this investigation, samples of the chemical (Hg1-xPbxBa2Ca1.8Mg0.2Cu3O8+δ) were prepared utilizing a solid-state reaction technique with a range of lead concentrations (x = 0.0, 0.05, 0.10, and 0.20). Specimens were pressed at 8 tons per square centimeter and then prepared at 1,138 K in the furnace. The crystalline structure and surface topography of all samples were examined using X-ray diffraction (XRD) and atomic force microscopy (AFM). X-ray diffraction results showed that all of the prepared samples had a tetragonal crystal structure. Also, the results showed that when lead was partially replaced with mercury, an increase in the lead value impacted the phase ratio, and lattice parameter values. The AFM results likewise showed excellent crystalline consistency and remarkable homogeneity during processing. The electrical resistivity was calculated as a function of temperature, and the results showed that all samples had a contagious behavior, as the resistivity decreased with decreasing temperature. The critical temperature was calculated and found to change, from 102, 96, 107, and 119 K, when increasing the lead values in the samples from 0.0 to 0.05, 0.10, and 0.20, respectively.

This research investigated the preparation of activated carbon derived from Krabok (Irvingia malayana) seed shells to improve the quality of crude glycerol obtained during biodiesel production. The activated carbon was prepared using a dry chemical activation method with NaOH, utilizing an innovative biomass incinerator. The results revealed that the resulting KC/AC-two-step exhibited favorable physicochemical adsorption properties, with a high surface area of 758.72 m2/g and an iodine number of 611.10 mg/g. These values meet the criteria of the industrial product standard for activated carbon No. TIS 900-2004, as specified by the Ministry of Industry in Thailand. Additionally, the adsorption efficiency for methylene blue reached an impressive 99.35 %. This developed activated carbon was then used to improve the quality of crude glycerol obtained from biodiesel production. The experimental results showed that the KC/AC-two-step increased the purity of crude glycerol to 73.61 %. In comparison, commercially available activated carbon (C/AC) resulted in a higher crude glycerol purity of 81.19 %, as analyzed by the GC technique. Additionally, the metal content (Zn, Cu, Fe, Pb, Cd, and Na) in purified glycerol using KC/AC-two-step was below the standards for heavy metals permitted in food and cosmeceuticals by the Food and Drug Administration of Thailand and the European Committee for Food Contact Materials and Articles. As a result, it can be inferred that Krabok seed shells have favorable properties for producing activated carbon suitable as an adsorbent to enhance crude glycerol purity. Furthermore, the improved crude glycerol from this research has potential for various industrial applications.

This work involves the development of a novel waste-derived carbon dots (CDs) conjugated with silver (Ag) nanohybrid system-based Fluorescence Resonance Energy Transfer (FRET) sensor for the detection of melamine. CDs and Ag nanoparticles served as energy donors and energy acceptors, respectively. CDs were synthesized from orange peel waste through a combined hydrothermal and ultra-sonication route. The synthesized CDs had hydroxyl, amino, and carboxyl groups on their surface, explaining that waste-derived CDs can act as reducing and stabilizing agents and showed strong absorption and fluorescence emission at 305 and 460 nm, respectively. The bandgap, linear refractive index, conduction band, and valance band potential of CDs were observed to be 2.86, 1.849, 1.14, and 4.002 eV, respectively. No significant difference was observed in the fluorescence properties at different pH (acid and alkaline) and ionic concentrations. Given their fluorescent nature, the synthesized CDs were used for the detection of melamine. The fluorescence of CDs was found to be quenched by Ag+ due to the FRET energy transfer between CDs to Ag. Notably, the zeta potential of Ag@CDs was changed from − 28.7 mV to − 30.6 mV after the incorporation of Ag+. Ag@CDs showed excellent selectivity and sensitivity toward the sensing of melamine in the aqueous solutions with the limit of detection ~ 0.85 μM. Increasing the melamine level also raises the FL intensity of Ag@CDs. The substrate was effectively used in the detection of melamine in milk as a real application and the recovery percentage was found to be 98.03%. Moreover, other adulterants such as urea and formaldehyde can be detected selectively by Ag@CDs. Overall, the synthesized Ag@CDs can be used as an efficient material for sensing applications involving such food adulterants.

Hierarchically porous carbon foam composites with highly dispersed Fe2O3 nanoparticles confined in the foam pores, facilely fabricated by hydrolysis-driven emulsion polymerization strategy. The as-generated acidic conditions of Fe3+ hydrolysis could catalyze the polymerization of phenolic resin, and the carbon-based composite materials containing iron oxides were obtained in situ. The structural characterization results show that HCF@Fe2O3 NPs-2 electrode has the largest specific surface area (549 m2/ g) and pore volume (0.46 cm3/ g). Electrochemical results indicates that typical HCF@Fe2O3 NPs-2 electrode displays good capacitive properties. including high specific capacitance (225 F/g at 0.2 A/g current density). Excellent magnification performance (capacity retention rate 80% as current density increases from 0.2 to 10 A/g). At the same time, HCF@SnO2 NPs was successfully synthesized by replacing hydrolyzed tin tetrachloride with ferric chloride. This study provides a new idea for the preparation of metal oxide–carbon matrix composites, and also highlights the potential of such carbon foams in application of energy storage.

Pharmaceutical products occurring in freshwater bodies create numerous problems for the water bodies owing to their bio-toxic nature. In order to remove such pharmaceutical pollutants, a novel Er-doped Bi4O5Br2/ g-C3N5 nanocomposite was prepared by one-pot synthesis and applied for the photocatalytic removal process. The Er ions doped on the surface of Bi4O5Br2/ g-C3N5 nanocomposite exhibited 97% degradation of tetracycline in 60 min under visible light irradiation, which is higher than pure g-C3N5 and Bi4O5Br2 photocatalysts. The improved photocatalytic properties are attributed to the outstanding visible light harvesting capacity and quick charge carrier separation efficiency which greatly reduced the recombination rate in the heterojunctions. Based on radical trapping experiments, the •O2 −, h+ and •OH radicals played a prominent role in the photodegradation reactions under visible light. Finally, the ternary Er-doped Bi4O5Br2/ g-C3N5 nanocomposite is effectively recyclable with quite a stable photocatalytic removal rate. This work enables a new perspective on the rational design of rare-earth-based nanocomposites for various pharmaceutical pollutants treatment processes.

In this study, we investigate the impact of Isophorone diisocyanate functionalized graphene oxide (IPDI-GO) on the flame retardancy of rigid polyurethane foam (RPUF). IPDI-GO was synthesized and introduced into the RPUF matrix. The flame retardancy of RPUF was significantly enhanced by the incorporation of IPDI-GO, as evidenced by a reduction in peak heat release rate (PHRR) by 25% and total smoke production (TSP) by 15% in comparison to pure RPUF when IPDI-GO was incorporated at 3 wt%. Scanning electron microscopy (SEM) revealed that IPDI-GO contributed to the formation of a compact, continuous char layer on the RPUF surface. This study underscores the potential of IPDI-GO as a promising flame retardant additive for RPUF.

Cellulose has experienced a renaissance as a precursor for carbon fibers (CFs). However, cellulose possesses intrinsic challenges as precursor substrate such as typically low carbon yield. This study examines the interplay of strategies to increase the carbonization yield of (ligno-) cellulosic fibers manufactured via a coagulation process. Using Design of Experiments, this article assesses the individual and combined effects of diammonium hydrogen phosphate (DAP), lignin, and CO2 activation on the carbonization yield and properties of cellulose-based carbon fibers. Synergistic effects are identified using the response surface methodology. This paper evidences that DAP and lignin could affect cellulose pyrolysis positively in terms of carbonization yield. Nevertheless, DAP and lignin do not have an additive effect on increasing the yield. In fact, combined DAP and lignin can affect negatively the carbonization yield within a certain composition range. Further, the thermogravimetric CO2 adsorption of the respective CFs was measured, showing relatively high values (ca. 2 mmol/g) at unsaturated pressure conditions. The CFs were microporous materials with potential applications in gas separation membranes and CO2 storage systems.

Carbon nanofibers (CNFs) are promising materials for the construction of energy devices, particularly organic solar cells. In the electrospinning process, polyacrylonitrile (PAN) has been utilized to generate nanofibers, which is the simplest and most popular method of creating carbon nanofibers (CNFs) followed by carbonization. The CNFs are coated on stainless steel (SS) plates and involve an electropolymerization process. The prepared Cu, CNF, CNF–Cu, PANI, PANI–Cu, CNF–PANI, and CNF–PANI–Cu electrode materials’ electrical conductivity was evaluated using cyclic voltammetry (CV) technique in 1 M H2SO4 electrolyte solution. Compared to others, the CNF–PANI–Cu electrode has higher conductivity that range is 3.0 mA. Moreover, the PANI, CNF–PANI, and CNF–PANI–Cu are coated on FTO plates and characterized for their optical properties (absorbance, transmittance, and emission) and electrical properties (CV and Impedance) for organic solar cell application. The functional groups, and morphology-average roughness of the electrode materials found by FT–IR, XRD, XPS, SEM, and TGA exhibit a strong correlation with each other. Finally, the electrode materials that have been characterized serve to support and act as the nature of the hole transport for organic solar cells.

Mg81Ni19-8wt.% REO (oxides of Lanthanum and Cerium) alloys were successfully prepared using mechanical alloying method with Mg-Ni alloy and REO powder. Phase analysis, structural characterization, and microstructure imagine of the alloys were conducted using X-ray diffraction (XRD), metallurgical microscope, and transmission electron microscopy (TEM) methods. Multi-phase structures, including the primary phase of Mg2Ni and several secondary phases of Mg + Mg2Ni, MgNi-LaO, and MgNi-CeO, were found in in the as-cast Mg81Ni19- 8wt.% REO alloys. XRD and TEM results showed that Ce exhibits variable valence behavior at various stages, and the addition of REO promotes the nanocrystalline of the alloy. The hydrogen absorption capacity of ball-milled Mg81Ni19 and Mg81Ni19- 8wt.%REO alloy for 2 h at 343 K is 1.34 wt.% and 1.83 wt.%, which are much larger than 0.94 wt.% of as-cast Mg81Ni19 alloy. The addition of REO led to a decrease of the thermal decomposition temperature of the alloy hydride by approximately 20 K and a reduction of the activation energy of the hydrogen desorption reaction by 10% and 13%, respectively.

The nanostructured dysprosium oxide ( Dy2O3) was synthesized by the co-precipitation method and incorporated with graphitic carbon nitride (g-C3N4) using the ultrasonication method. The resultant product is denoted as Dy2O3/ g-C3N4 nanocomposite which was further used for electrochemical sensing of riboflavin (RF). The physicochemical properties of Dy2O3/ g-C3N4 nanocomposite were examined using several characterization techniques. The obtained results exhibit the nanocomposite formation with the preferred elemental compositions, functional groups, crystalline phase and desired surface morphology. The electrocatalytic performance of Dy2O3/ g-C3N4 nanocomposite was scrutinized with a glassy carbon electrode (GCE) via differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques with the conventional three-electrode system. The modified electrode distributes more active surface area suggesting high electrocatalytic activity for the RF detection with two linear ranges (0.001–40 μM and 40–150 μM), a low detection limit of 48 nM and sound sensitivity (2.5261 μA μM−1 cm− 2). Further, the designed sensor possesses high selectivity, excellent stability, repeatability and reproducibility. Finally, the fabricated sensor was successfully estimated for the detection of RF in actual food sample analysis using honey and milk with better recovery.

Black phosphorus (BP) is incorporated in the electrochemical detection of uric acid (UA) to form few layers of BP nanosheets (BPNS)-modified glassy carbon electrodes (BPNS/GCE), investigated by means of ultrasound-assisted liquid-phase exfoliation. We find a significant increase in the peak current magnitude and positive potential shift in the electrochemical response of BPNS/GCE, which may be attributed to the larger specific surface area and good charge transfer ability of BPNS. Further, the electrochemical response of BPNS/GCE is evaluated under different conditions to achieve the optimal conditions. UA detection using differential pulse voltammetry (DPV) shows linear response within the range of 1–1000 μM with a detection limit of 0.33 μM. This work reveals new applications of BP nanomaterials in the electrochemical sensing, thereby promoting further advancement in terms of practical applications of two-dimensional nanomaterials.

This study presents the fabrication and application of a graphene-assisted voltammetry platform for the sensitive detection of nitrate ions in PM2.5 (atmospheric aerosols with a maximum diameter of 2.5 μm). The MoS2/ reduced graphene oxide/ glassy carbon electrode ( MoS2/rGO/GCE) was prepared using a simple and efficient electrochemical deposition method. The rationale behind selecting MoS2/ rGO stems from their individual properties that, when combined, can enhance the electrode’s performance. MoS2 offers excellent electro-catalytic activity and selectivity for nitrate ion detection, while rGO provides high conductivity and a large surface area for enhanced sensitivity. The electrochemical performance of MoS2/ rGO/GCE was investigated and compared with MoS2/ GCE and bare GCE using cyclic voltammetry and electrochemical impedance spectroscopy. The results demonstrated that MoS2/ rGO/GCE exhibited enhanced electro-catalytic activity, high conductivity, and improved selectivity for nitrate ion detection. The optimal pH value for detecting nitrate ions was determined to be 8.0. Differential pulse voltammetry (DPV) was employed to investigate the linear range and detection limit of nitrate ions on MoS2/ rGO/GCE, resulting in a linear range from 1 to 300 μM and a detection limit of 0.35 μM. The reproducibility and the stability of MoS2/ rGO/GCE were assessed, showing satisfactory performance. Real sample analysis from Chengdu City showed a strong correlation between the results obtained using MoS2/ rGO/GCE and ion chromatography, highlighting its potential application in monitoring nitrate ions in PM2.5. The findings of this study contribute to the development of a graphene-assisted voltammetry platform for sensitive nitrate ion detection in PM2.5, offering potential benefits for real-time air pollution monitoring and environmental health assessments.

A glassy carbon electrode modified with a composite consisting of electrodeposited chitosan and carboxylated multi-walled carbon nanotubes (e-CS/MWCNTs/GCE) was used as a working electrode for simultaneous determination of dopamine (DA), serotonin (5-HT) and melatonin (MT), which were related to circadian rhythms. The electrochemical characterizations of the working electrode were carried out via electrochemical impedance spectroscopy and chronocoulometry. It was found that electrochemical modification method, that was cyclic voltammetry, may can cause continuous CS polymerization on MWCNTs surface to form a dense membrane with more active sites on the electrode, and the electrochemically active surface area of e-CS/MWCNTs/GCE obtained was about 7 times that of GCE. The electrochemical behaviour of DA, 5-HT and MT on working electrode were carried out via differential pulse voltammetry and cyclic voltammetry. The results showed that e-CS/MWCNTs/GCE solved the problem that the bare electrode could not detect three substances simultaneously, and can catalyze oxidation potential difference as low as 0.17 V of two substances reaction at the same time, indicating very good electrocatalytic activity. By optimizing the detection conditions, the sensor showed a good linear response to DA, 5-HT and MT in the range of 20-1000 μmol/L, 9-1000 μmol/L and 20-1000 μmol/L, and the detection limits were 12 μmol/L, 10 μmol/L and 22 μmol/L (S/N = 3), respectively. In addition, the proposed sensor was successfully applied to the simultaneous detection of DA, 5-HT and MT in human saliva samples.

A simple and one-pot synthetic procedure using two different sources has been demonstrated to prepare heteroatoms doped reduced graphene oxide such as nitrogen-doped reduced graphene oxide (N-RGO) and sulfur-doped reduced graphene oxide (S-RGO). The N-RGO has been hydrothermally synthesized using urea as nitrogen precursor, wherein the S-RGO has been synthesized using dimethyl sulfoxide (DMSO) as sulfur precursor. The successful N-doping, S-doping and other physicochemical properties of N-RGO and S-RGO have been confirmed with different spectroscopic and electrochemical techniques. The results indicated that doping into the graphene structure exhibits a high conductivity and a better transfer of charge. Moreover, heteroatoms doped graphene (N-RGO and S-RGO) and graphene-related materials (RGO) have been applied for the individual detection of uric acid (UA). Interestingly, the N-RGO exhibited a lower limit of detection (LOD, S/N = 3) of 2.7 10– 5 M for UA (10–1000 μM) compared with undoped RGO and S-RGO. Furthermore, the simultaneous detection of UA in the presence of Xanthine (XA) has been demonstrated a wide linear range of detection for UA: 10–1000 μM, with unchanged concentration of XA to be 200 μM, and exhibited a low limit of detection of 8.7 10− 5 M ( S∕N = 3) for UA. This modified sensor based on N-RGO has revealed a high selectivity and reproducibility thanks to its large surface area, high catalytic properties, and chemical structure. Indeed, the practical applicability of the proposed sensor has been evaluated in milk samples even in the presence of high concentrations of UA with satisfactory results.

In this research, in order to increase the oxidation resistance of graphite, kaolin and alumina powder with different ratios (26A-74S, 49A-51S, 72A-28S) and slurry method were used to create an aluminosilicate coating on the graphite substrate. In order to reduce the difference in the coefficients of thermal expansion of graphite with aluminosilicate coating, aluminum metaphosphate coating as an interlayer was prepared on the surface of graphite by cathodic electrochemical treatment. The isothermal oxidation test of the samples was carried out in air at a temperature of 1250 °C for 1, 3 and 5 h. The microstructure, chemical composition, and phase components of the coating were, respectively, analyzed by scanning electron microscope equipped with an energy-dispersive spectrometer and X-ray diffraction. The results indicated that, by increasing the withdrawal speed of the samples in slurry method, the amount of changes in the weight of the samples has increased and therefore had a direct effect on oxidation. In addition, it was approved that, at high-temperature oxidation, AlPO4 glass phase forms on aluminum metaphosphate interlayer which retards graphite oxidation. Along with aluminum metaphosphate, aluminosilicate coating also produces a glass phase which fills and seals the voids on the surface which prevents the oxygen to reach the surface of graphite. The created double-layer coating including an interlayer of aluminum metaphosphate + slurry coating prepared with the ratio of 26A-74S as the optimal coating in this research was able to increase the oxidation resistance of graphite by 73% at a temperature of 1250 °C.