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The science laboratory is a politically entrenched space where complex power relations interplay while social agents learn about the rules and routines to ensure safety, precision and reproducibility in research work. This paper presents a case study of two Singaporean students undergoing apprenticeship in a 3-year school-based School Scientist Programme. They engaged in an open and authentic science inquiry involving chemical synthesis in the school's science laboratory under the apprenticeship of an in-house School Scientist who started the programme. The goals of this paper are to offer an alternative--critical and nuanced--lens to the dominant positivist and social constructivist discourse about science research apprenticeship. Using visual ethnography approach, we collected videos and photographs of the students' and School Scientist's interactions during the science research over the first 18 months of the programme. The study documented critical events that showed shifts in control over knowledge construction and mastery of the chemical synthesis craft as the science research progressed. This paper contributes to the Foucauldian theory of power in offering an alternative view to the dialectical explanation of power and knowledge. First, it shows that while there is an overall gain in knowledge of chemical synthesis increased during the apprenticeship, the power relationship fluctuates when a different genre of chemical synthesis work was introduced. The fluctuation is related to the overtaking and relinquishing of control (power) with the latter leading to the construction of knowledge. Second, we show how the power relationship, involving the interplay of power and knowledge between the expert and apprentice, is more interconnected and complex. The findings of this study have implications for teachers who want to plan and enact authentic science inquiry with their students.

This paper presents findings from a content analysis of 650 empirical chemistry education research papers published in two top-tiered chemistry education journals "Chemistry Education Research and Practice" and "Journal of Chemical Education," and four top-tiered science education journals "International Journal of Science Education," "Journal of Research in Science Teaching," "Research in Science Teaching and Science Education" from 2004-2013. We found that empirical chemistry education research (CER) papers accounted for 7.7 percent of the publications in the four science education journals. The most highly published area of research was in conceptions and conceptual change and most studies adopted mixed methods. The majority of the studies were conducted in higher education contexts and in the United States. Researchers who publish prolifically in the field included Vicente Talanquer, Derek Cheung, Michael Sanger, Keith Taber, Melanie Cooper and Marcy Towns. Current research trends and gaps are illuminated and possible future work in CER is discussed in the paper.

In this paper, we define flip teaching as a curricular platform that uses various strategies, tools, and pedagogies to engage learners in self-directed learning outside the classroom before face-to-face meetings with teachers in the classroom. With this understanding, we adopted flip teaching in the design and enactment of one Year 1 and one Year 2 undergraduate chemistry laboratory session at a higher education institution. The undergraduates viewed videos demonstrating the practical procedures and answered pre-laboratory questions posted on the institution's mobile device application before the laboratory lessons. Analyses of the lesson videos, interviews with the undergraduates and instructors, and undergraduate artefacts showed that the undergraduates had developed a better understanding of the theory undergirding the procedures before they performed the practical, and were able to decipher the complex practical procedures. They also experienced less anxiety about the complex practical steps and setup, and subsequently, improved work efficiency. The findings of this study have implications for chemistry educators looking for ways to improve on the design and enactment of the laboratory curriculum to enhance the undergraduates' self-directed learning.

The esterification reaction of salicylic acid with ethanol is performed in presence of dissolved 12-tungstophosphoric Brønsted-Lowry acid catalyst, a Keggin-type polyoxometalate (POM). The monitoring of the reaction with smell and the recovery of the catalyst with sight is presented. Formation of the sweet-scented ester is apparent from the smell. After the reaction, the dissolved POM catalyst is recovered via encapsulation into a metal-organic framework (MOF) made of copper nitrate and benzene-1,3,5-tricarboxylic acid (BTC), Cu[subscript 3](BTC)[subscript 2] (also called HKUST-1). The encapsulation causes a color change from a greenish liquid to a suspension of blue catalyst-containing particles. The catalyst can be recovered by filtration, dissolved in a new batch of reactants, and reused. The simplicity of this reaction and the accessibility of the catalytic chemistry to human senses, avoiding the need of analytical tools, make this reaction suitable for a classroom demonstration of catalysis for educational purposes.

Malaysia, a country with a tropical climate characterized by consistent warmth and year-long high humidity, houses the perfect conditions for mushroom growth. Recently, there has been a surge in back-to-nature activities in Malaysia. However, many participants lack prior knowledge about the local flora and fungi, leading to a rise in mushroom poisoning cases, some of which have been fatal. Despite thorough research, there is a notable lack of identification studies specifically focused on mushroom species in Malaysia. Identifying these species is crucial for medical providers to effectively counteract the toxins from ingested mushrooms and also serves as an important educational tool. This study aims to determine the most suitable architecture for mushroom identification, focusing specifically on mushroom species found in Malaysia. A dataset of these mushrooms was curated, augmented, and processed through multiple variants of Vision Transformers (ViTs) and ResNet models, with uniform hyperparameters to ensure fairness. The results indicate that the ViT-L/16 model achieved the highest accuracy at 90.47%.

This study examined the effects of high-pressure homogenization (HPH) and ultrasonication pre-treatment on the structural and physicochemical properties of proteins extracted from defatted Nannochloropsis Oceania biomass (DNOB). HPH treatment was found to enhance the solubility of protein extracted from DNOB compared to ultrasound, where samples pretreated with three passes (3P) of HPH exhibited lower solubility than two passes (2P). The morphology of extracted samples was visualized by scanning electron microscopy, which HPH pre-treatment, especially with more passes, were able to breakdown DNOB into fragments. Alternatively, more holes were displayed on the surface of the extracts pretreated with ultrasound especially when higher amplitude applied. The particle size of extracts from HPH3P (129.5 µm) significant dropped from HPH2P (314.25 µm), where samples pretreated with ultrasound at 20 % amplitude (US20) also decreased in particle size compared to 40 % amplitude (US40), from 115.25 µm to 78.22 µm. Protein flexibility of DNOB extracts were enhanced by both HPH2P and HPH3P but decreased for ultrasound samples. β-sheets were found to be the most abundant protein secondary structure for all samples, where samples treated with HPH3P contained the highest percentage of β-sheets (72 %) than control, HPH2P, ultrasonication at 20 and 40 % amplitude (52–62 %). The high percentage of β-sheets found in HPH3P sample also contributed to its outstanding emulsifying properties which stood out among all, especially at concentrations over 1 mg/ml. Results obtained from this study helped to direct the application of DNOB extracts as functional food ingredient for future food innovation.

This study proposes an occupant-centric control strategy for residential heating systems, aiming to enhance thermal comfort and reduce energy consumption. A sensor station utilizing a frequency-modulated continuous wave radar sensor was developed to detect occupancy and infer activities within residential spaces. By analyzing field measurement data, schedules for occupancy and activities were established. These schedules were then used to implement a variable control strategy for the hydronic radiant heating system, adjusting its operating characteristics based on the identified activities. The proposed control strategy, which includes resetting the indoor set temperature during unoccupied periods and adjusting it during sleep to account for changes in metabolic rate and clothing insulation, resulted in significant energy savings. Compared to continuous operation, the hydronic radiant heating system’s energy consumption was reduced by approximately 21% on peak load days and up to 34% over three winter months. This study demonstrates the potential of occupant-centric control for achieving substantial energy savings in residential buildings while maintaining occupant thermal comfort.

The realization of long-range magnetic ordering in two-dimensional (2D) van der Waals systems significantly expands the scope of the 2D family as well as their possible spin-related phenomena and device applications. The atomically thin nature of 2D materials makes their magnetically ordered states sensitive to local environments, and this necessitates advanced characterization at the atomic scale. Here, we briefly review several representative 2D magnetic systems, namely, iron chalcogenides, chromium chalcogenides, chromium trihalides, and their heterostructures. With powerful scanning-probe microscopy, atomically resolved characterization of their crystalline configurations, electronic structures, and magnetization distributions has been achieved, and novel phenomena such as giant tunneling magnetoresistance and topological superconductivity have been observed. Finally, we discuss the challenges and new perspectives in this flourishing field.

To date, extensively high demand for hydrogen peroxide (H2O2) has been predominantly supplied by the anthraquinone process for several worldwide applications, encompassing wastewater treatment, environmental remediation, and chemical synthesis. However, the compacted manufacturing, massive energy input and the release of tremendous wastes have restricted commercialization feasibility. Regards to mitigate such issues, the photocatalytic H2O2 production by utilizing g-C3N4 catalysts has endowed a greener, sustainable and promising alternative, considering that it involves water and oxygen as reactants in the present of sunlight as energy input. Herein, we have manifested a comprehensive overview of the research progress for g-C3N4-based semiconductors for photocatalytic H2O2 generation. This review has systematically elucidated state-of-the-art development of different modifications on g-C3N4 to unravel the fundamental mechanism of H2O2 evolution via oxygen reduction reaction (ORR) and water oxidation reaction (WOR). In addition, the contribution made by vacancy introduction, doping, heterogenization, and co-catalyst passivation with respect to photoefficiency enhancement have been clarified. Furthermore, the current challenges and perspective of future development directions on photocatalytic H2O2 production have also been highlighted. As such, g-C3N4 stands as the next step toward advancement in the configuration and modulation of high-efficiency photocatalysts.

Singlet fission excited-state relaxation, as observed in covalently linked dimers, could allow energy-conversion efficiencies in photovoltaic devices beyond the Shockley–Queisser limit. Here, the authors study the effect of the molecular configuration of two covalently ortho-linked pyrene dimers on singlet fission dynamics using steady-state and time-resolved spectroscopies.

Abstract Metal contacts to two-dimensional (2D) semiconductors are often plagued by the strong Fermi level pinning (FLP) effect which reduces the tunability of the Schottky barrier height (SBH) and degrades the performance of 2D semiconductor devices. Here, we show that MoSi2N4 and WSi2N4 monolayers—an emerging 2D semiconductor family with exceptional physical properties—exhibit strongly suppressed FLP and wide-range tunable SBH. An exceptionally large SBH slope parameter of S ≈ 0.7 is obtained which outperforms the vast majority of other 2D semiconductors. Such intriguing behavior arises from the septuple-layered morphology of MoSi2N4 and WSi2N4 monolayers in which the semiconducting electronic states are protected by the outlying Si–N sublayer. We identify Ti, Sc, and Ni as highly efficient Ohmic contacts to MoSi2N4 and WSi2N4 with zero interface tunneling barrier. Our findings reveal the potential of MoSi2N4 and WSi2N4 as a practical platform for designing high-performance and energy-efficient 2D semiconductor electronic devices.

Abstract The construction of conjugated covalent organic frameworks (COFs) with strong C–C bond linkage remains a big challenge. Herein, we report a new strategy by using an oxidative C–C coupling reaction between electron-rich pyrrole rings at a liquid–liquid interface. Two threefold symmetric monomers containing three terminal pyrrole units were tested, and both gave two-dimensional conjugated COF films with good crystallinity. The bipyrrole units in the as-formed COFs are partially doped, which can be reduced to the neutral form by hydrazine and redoped by I2 vapor. The I2-doped films showed high conductivity (1.35 S/m). Meanwhile, the unpaired electrons exhibited moderate interlayer antiferromagnetic coupling.

Abstract State-of-the-art memristors are mostly formed by vertical metal–insulator–metal (MIM) structure, which rely on the formation of conductive filaments for resistive switching (RS). However, owing to the stochastic formation of filament, the set/reset voltage of vertical MIM memristors is difficult to control, which results in poor temporal and spatial switching uniformity. Here, a two-terminal lateral memristor based on electron-beam-irradiated rhenium disulfide (ReS2) is realized, which unveils a resistive switching mechanism based on Schottky barrier height (SBH) modulation. The devices exhibit a forming-free, stable gradual RS characteristic, and simultaneously achieve a small transition voltage variation during positive and negative sweeps (6.3%/5.3%). The RS is attributed to the motion of sulfur vacancies induced by voltage bias in the device, which modulates the ReS2/metal SBH. The gradual SBH modulation stabilizes the temporal variation in contrast to the abrupt RS in MIM-based memristors. Moreover, the emulation of long-term synaptic plasticity of biological synapses is demonstrated using the device, manifesting its potential as artificial synapse for energy-efficient neuromorphic computing applications.

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by cognitive and functional impairment. Recent research has focused on the deregulation of microRNAs (miRNAs) in blood as the potential biomarkers for AD. As such, a differential expression analysis of miRNAs was conducted in this study using an integrated framework that utilized the advantages of statistical and machine learning approaches. Three miRNA candidates that showed the strongest significance and correlation with each other, namely hsa-miR-6501-5p, hsa-miR-4433b-5p, and hsa-miR-143-3p, were identified. The roles and functions of the identified differentiated miRNA candidates with AD development were verified by predicting their target mRNAs, and their networks of interaction in AD pathogenesis were investigated. Pathway analysis showed that the pathways involved in contributing to the development of AD included oxidative phosphorylation, mitochondrial dysfunction, and calcium-mediated signalling. This study supports evidence that the miRNA expression changes in AD and indicates the need for further study in this area.

The growing health awareness among consumers has increased the demand for non-dairy-based products containing probiotics. However, the incorporation of probiotics in non-dairy matrices is challenging, and probiotics tend to have a low survival rate in these matrices and subsequently perform poorly in the gastrointestinal system. Encapsulation of probiotics with a physical barrier could preserve the survivability of probiotics and subsequently improve delivery efficiency to the host. This article aimed to review the effectiveness of encapsulation techniques (coacervation, extrusion, emulsion, spray-drying, freeze-drying, fluidized bed coating, spray chilling, layer-by-layer, and co-encapsulation) and biomaterials (carbohydrate-, fat-, and protein-based) on the viability of probiotics under the harsh conditions of food processing, storage, and along the gastrointestinal passage. Recent studies on probiotic encapsulations using non-dairy food matrices, such as fruits, fruit and vegetable juices, fermented rice beverages, tea, jelly-like desserts, bakery products, sauces, and gum products, were also included in this review. Overall, co-encapsulation of probiotics with prebiotics was found to be effective in preserving the viability of probiotics in non-dairy food matrices. Encapsulation techniques could add value and widen the application of probiotics in the non-dairy food market and future perspectives in this area.

In recent years, there has been much interest in developing advanced and innovative approaches for sensing applications in various fields, including agriculture and environmental remediation. The development of novel sensors for detecting heavy metals using nanomaterials has emerged as a rapidly developing research area due to its high availability and sustainability. This review emphasized the naturally derived and engineered nanomaterials that have the potential to be applied as sensing reagents to interact with metal ions or as reducing and stabilizing agents to synthesize metallic nanoparticles for the detection of heavy metal ions. This review also focused on the recent advancement of nanotechnology-based detection methods using naturally derived and engineered materials, with a summary of their sensitivity and selectivity towards heavy metals. This review paper covers the pros and cons of sensing applications with recent research published from 2015 to 2022.

Heavy metal contamination has spread around the world, particularly in emerging countries. This study aimed to assess the effectiveness of starch/eggshell/orange peel-activated carbon-based composite films in removing cadmium (II) ions from water samples. X-ray diffraction and scanning electron microscopy were used to characterize the composite films. The effect of Cd2+ was studied using a UV-Vis spectrophotometer and atomic absorption spectroscopy. The morphology of the composite film reveals a highly porous and rough surface with more open channels and a non-uniform honeycomb, indicating that the film has a high potential to adsorb Cd2+. The diffraction peaks for this film were found to be at 13.74°, 17.45°, 18.4°, and 23.6°, indicating a typical crystalline A-type packing arrangement within the starch granules. The results indicate that crystalline structure was unaffected by the addition of eggshell powder and orange peel-activated carbon. In 0.5 mg L−1 and 1.0 mg L−1 Cd2+ ions, the composite film removed 100% and 99.7% of the Cd2+, respectively, while the maximum removal efficiency for methylene blue was 93.75%. Thus, the current study shows that starch/eggshell/orange peel activated carbon film has a high potential for commercial activated carbon as a low-cost adsorbent.

Light but strong carbon fibers have been utilized as effective reinforcing lattices for cement matrices. However, to explore the intrinsic properties of carbon fibers within the cement matrix, the interfacial behavior between the fiber and matrix must be understood in terms of the bond strength as well as the interfacial failure mode. In the present work, we evaluated the pullout properties of carbon fiber bundles from a cementitious matrix after the fibers were modified via one of three plasma treatments using argon, nitrogen, or oxygen. The plasma-treated carbon fibers were characterized using Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning tunneling microscopy. The treatments introduced hydrophilic functional groups on the carbon fibers’ surfaces and increased their surface roughness. With an appropriate amount of hydrophilic groups on the carbon fiber surface, the rate of hydration was accelerated, which led to a denser cement structure surrounding the carbon fibers. In addition, the fibers’ surface roughness was critical toward improving mechanical interlocking between the fibers and cement matrix. The highest interfacial shear strength for the argon plasma-treated sample can be explained by the improvement in surface roughness without degrading the mechanical strength of the carbon fiber, as well as the modification of the surface from hydrophobic to hydrophilic.

High compliance and muscle-alike soft robotic grippers have shown promising performance in addressing the challenges in traditional rigid grippers. Nevertheless, a lack of control feedback (gasping speed and contact force) in a grasping operation can result in undetectable slipping and false positioning. In this study, a pneumatically driven and self-powered soft robotic gripper that can recognize the grabbed object is reported. We integrated pressure (P-TENG) and bend (B-TENG) triboelectric sensors into a soft robotic gripper to transduce the features of gripped objects in a pick-and-place operation. Both the P-TENG and B-TENG sensors are fabricated using a porous structure made of soft Ecoflex and Euthethic Gallium-Indium nanocomposite (Eco-EGaIn). The output voltage of this porous setup has been improved by 63%, as compared to the non-porous structure. The developed soft gripper successfully recognizes three different objects, cylinder, cuboid, and pyramid prism, with a good accuracy of 91.67% and has shown its potential to be beneficial in the assembly lines, sorting, VR/AR application, and education training.

Xanthine oxidase (XO) plays an important role in purine degradation in humans. The study aimed to determine the XO inhibitory potential of Chrysanthemum morifolium dried flower ethyl acetate sub-fractions and its anti-hyperuricemic effect in rat models. Bioassay-guided fractionation based on XO inhibitory assay was employed to obtain bioactive fractions and sub-fractions. In vitro cytotoxicity and cellular antioxidant capacity of the sub-fraction and its mode of XO inhibition were also investigated. The anti-hyperuricemic effect of the bioactive sub-fraction was investigated using rat models via oral consumption, and followed by an XO mRNA gene expression study. The compounds in the bioactive sub-fractions were identified putatively using HPLC-Q-TOF-MS/MS. Ethyl acetate (EtOAc) fraction exhibited the highest XO inhibition among the fractions. It was further fractionated into 15 sub-fractions. F10 exhibited high XO inhibitory activity, cellular pro-proliferative effect, and intracellular antioxidant activity among the sub-fractions tested. This sub-fraction was non-cytotoxic at 0.1–10 µg/mL, and very effective in lowering serum and urine uric acid level in rat models upon oral consumption. A total of 26 known compounds were identified and seven unknown compounds were detected via HPLC-Q-TOF–MS/MS analysis. The possible mechanisms contributing to the anti-hyperuricemic effect were suggested to be the non-competitive inhibition of XO enzyme, XO gene expression down-regulation, and the enhancement of uric acid excretion.

The generation of hepatic spheroids is beneficial for a variety of potential applications, including drug development, disease modeling, transplantation, and regenerative medicine. Natural hydrogels are obtained from tissues and have been widely used to promote the growth, differentiation, and retention of specific functionalities of hepatocytes. However, relying on natural hydrogels for the generation of hepatic spheroids, which have batch to batch variations, may in turn limit the previously mentioned potential applications. For this reason, we researched a way to establish a three-dimensional (3D) culture system that more closely mimics the interaction between hepatocytes and their surrounding microenvironments, thereby potentially offering a more promising and suitable system for drug development, disease modeling, transplantation, and regenerative medicine. Here, we developed self-assembling and bioactive hybrid hydrogels to support the generation and growth of hepatic spheroids. Our hybrid hydrogels (PC4/Cultrex) inspired by the sandcastle worm, an Arg-Gly-Asp (RGD) cell adhesion sequence, and bioactive molecules derived from Cultrex BME (Basement Membrane Extract). By performing optimizations to the design, the PC4/Cultrex hybrid hydrogels can enhance HepG2 cells to form spheroids and express their molecular signatures (e.g., Cyp3A4, Cyp7a1, A1at, Afp, Ck7, Ck1, and E-cad). Our study demonstrated that this hybrid hydrogel system offers potential advantages for hepatocytes in proliferating, differentiating, and self-organizing to form hepatic spheroids in a more controllable and reproducible manner. In addition, it is a versatile and cost-effective method for 3D tissue cultures in mass quantities. Importantly, we demonstrate that it is feasible to adapt a bioinspired approach to design biomaterials for 3D culture systems, which accelerates the design of novel peptide structures and broadens our research choices on peptide-based hydrogels.

Solvothermal synthesis has shown to have a great potential to synthesize Zinc Oxide nanoparticles (ZnO NPs) with less than 10 nm size. In this study, we present a rapid synthesis of ZnO NPs in which ZnO NPs with more uniform shape and highly dispersed were synthesized using zinc acetate dihydrate (Zn(CH3COO)2∙2H2O) and potassium hydroxide (KOH) as a precursor and absolute ethanol as solvent via solvothermal method. Few techniques were exploited to characterize synthesized ZnO NPs including X-ray diffraction (XRD), transmission electron microscope (TEM), Brunauer-Emmett-Teller (BET), energy-dispersive X-ray spectroscopy (EDX), fourier transform infrared (FT-IR) spectroscopy, and ultraviolet visible (UV-Vis) spectroscopy. Synthesized ZnO NPs that were prepared via solvothermal synthesis method at 60oC for 3 hours exhibited a wurtzite structure with a crystalline size of 10.08 nm and particle size of 7.4 ± 1.2 nm. The UV-vis absorption spectrum has shown peak at 357 nm indicate the presence of ZnO NPs. Hence, better quality with uniform size ZnO NPs can be easily synthesized with reduced amount of time via solvothermal synthesis method rather than using other complicated and lengthy synthesis methods.

In this study, we evaluated the response spectra of 24 earthquake series, which includes 15 from the Kumamoto earthquake series and 9 from the Pohang earthquake series, and explored the effects of earthquake magnitude on the resonance frequencies of structures and buildings. Furthermore, the observations of this study were compared with the design response spectra, Regulatory Guide 1.60 (The United States Nuclear Regulatory Commission, 1973) for Korean nuclear power plants, and with the Korean Building Code (MOLIT, 2016, hereinafter referred to as KBC 2016) for general structures and buildings. The response spectra, after normalization with reference to the peak ground acceleration (PGA), were derived using a total of 423 horizontal and vertical accelerations. It was observed that the shapes of the horizontal and vertical response spectra were strongly dependent on the magnitude of the earthquake and the resonance frequency. Given the strong dependence of the response on the magnitude, it is suggested to consider magnitude > ML ~ 6.0 when establishing design response spectra. Compared to inland areas, a fairly higher amplitude of response at significantly lower frequency ranges could be attributed to the local geological environment of Jeju Island, which was formed by a surface volcano eruption and the distribution of unconsolidated Pleistocene marine sediments in the Jeju area. It is necessary to study the characteristic influence of layers with low shear wave velocity distributed in the Jeju region on seismic responses more rigorously while considering the frequency band and amplitudes at the surface of Jeju. The resonance frequencies of general low-rise and mid-rise buildings by the brief formula and those by design response spectra both suggested by KBC 2016 were overlapped, and these indicated that the seismic hazard could be much higher on general buildings in the Jeju region than in inland areas. Lastly, it is necessary to make the design standard criteria for Reg. Guide 1.60 and KBC 2016 more conservative in the lower frequency range of higher than 0.6 Hz and 2.0–6.0 Hz, respectively, which is significantly lower than those of the inland area, and to establish improved design response spectra with site-specific seismic design standards by referencing large amounts of qualitative data from the region around the Korean Peninsula.

Water pollution by toxic substances, such as dye molecules, remains a major environmental problem that needs to be solved. In the present work, the magnetic composite hydrogel based on the poly(2-(methacryloyloxy)-N-(2-hydroxyethyl)-N,N-dimethylethan-1-aminium bromide-co-N-isopropylacrylamide) copolymer with incorporated Fe3O4 particles ((poly(DMAEAB-co-NIPAm)@Fe3O4)) was prepared by an in situ synthesis technique for the efficient removal of dye molecules from water. The successfully synthesized magnetic hydrogel was characterized by FTIR, XRD, TGA, and TEM. The removal efficiency of the anionic dye bromophenol blue (BPB) and the cationic dye rhodamine B (RDM) by the prepared hydrogel adsorbents was evaluated. Various adsorption parameters, including the concentration of adsorbents and adsorption time, were also investigated. The results showed that the synthesized magnetic hydrogel had excellent BPB removal performance compared to the removal of RDM. The optimum adsorbent concentration for 0.5 mM BPB solution was approximately 0.5 g/L, and the removal efficiency was more than 99%. The kinetics data of BPB removal fitted well into the pseudo-2nd-order model, indicating that BPB dye adsorption involves chemical adsorption and physical adsorption. In addition, recycling studies were conducted to examine the reusability of the magnetic hydrogel for BPB removal for up to five cycles and the hydrogel could be reused without losing its high removal efficiency. The magnetic hydrogel poly(DMAEAB-co-NIPAm)@Fe3O4 with high removal efficiency, good selectivity, and reusability shows great potential for the removal of anionic dyes in wastewater treatment.

Ferroelectric (FE) Hf1−xZrxO2 is a potential candidate for emerging memory in artificial intelligence (AI) and neuromorphic computation due to its non-volatility for data storage with natural bi-stable characteristics. This study experimentally characterizes and demonstrates the FE and antiferroelectric (AFE) material properties, which are modulated from doped Zr incorporated in the HfO2-system, with a diode-junction current for memory operations. Unipolar operations on one of the two hysteretic polarization branch loops of the mixed FE and AFE material give a low program voltage of 3 V with an ON/OFF ratio >100. This also benefits the switching endurance, which reaches >109 cycles. A model based on the polarization switching and tunneling mechanisms is revealed in the (A)FE diode to explain the bipolar and unipolar sweeps. In addition, the proposed FE-AFE diode with Hf1−xZrxO2 has a superior cycling endurance and lower stimulation voltage compared to perovskite FE-diodes due to its scaling capability for resistive FE memory devices.

In this work, a study was carried out to estimate a look-up table (LUT) that converts a camera image plane to a birds eye view (BEV) plane using a single camera. The traditional camera pose estimation fields require high costs in researching and manufacturing autonomous vehicles for the future and may require pre-configured infra. This paper proposes an autonomous vehicle driving camera calibration system that is low cost and utilizes low infra. A network that outputs an image in the form of an LUT that converts the image into a BEV by estimating the camera pose under urban road driving conditions using a single camera was studied. We propose a network that predicts human-like poses from a single image. We collected synthetic data using a simulator, made BEV and LUT as ground truth, and utilized the proposed network and ground truth to train pose estimation function. In the progress, it predicts the pose by deciphering the semantic segmentation feature and increases its performance by attaching a layer that handles the overall direction of the network. The network outputs camera angle (roll/pitch/yaw) on the 3D coordinate system so that the user can monitor learning. Since the network’s output is a LUT, there is no need for additional calculation, and real-time performance is improved.

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is one of the most popular conducting polymers and widely used as polymer thermoelectric materials, and its thermoelectric performance could be improved by a variety of post-treatment processes. This paper reported two series of post-treatment methods to enhance the thermoelectric performance. The first series method included pre-treatment of PEDOT:PSS film with formamide, followed by imidazolium-based ionic liquids. The second series method included pre-treatment of PEDOT:PSS film with formamide, followed by sodium formaldehyde sulfoxylate, and finally imidazolium-based ionic liquids. Two series of post-treatment methods significantly improved the power factor of PEDOT:PSS when compared to that of PEDOT:PSS treated with formamide only. For example, using the first series post-treatment method with 40 vol.% ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl) amide, the Seebeck coefficient of the PEDOT:PSS film increased from 14.9 to 28.5 μV/K although the electrical conductivity reduced from 2,873 to 1,701 S/cm, resulting in a substantial improvement in the overall power factor from 63.6 to 137.8 μW/K2m. The electrical conductivity enhancement in the formamide-treatment process was in part ascribed to the removal of the insulating PSS component. Further treatment of PEDOT:PSS film with ionic liquid caused dedoping of PEDOT and hence increased in Seebeck coefficient. In contrast, second series post-treatment method led to the reduction in electrical conductivity from 2,873 to 641 S/cm but a big improvement in the Seebeck coefficient from 14.9 to 61.1 μV/K and thus the overall power factor reached up to ~239.2 μW/K2m. Apart from the improvement in electrical conductivity, the increase in Seebeck coefficient is on account of the substantial dedoping of PEDOT polymer to its neutral form and thus leads to the big improvement of its Seebeck coefficient. The environmental stability of ionic liquid-treated PEDOT:PSS films were examined. It was found that the ionic liquid treated PEDOT:PSS retained more than 70% Seebeck coefficient and electrical conductivity at 75% RH humidity and 70°C for 480 h. The improved long-term TE stability is attributed to the strong ionic interaction between sulfonate anions and bulky imidazolium cations that effectively block the penetration of water and lessen the tendency to take up water from the air.

Biofuel cell (BFC) electrodes are typically manufactured by combining enzymes that act as catalysts with conductive carbon nanomaterials in a form of enzyme-nanocomposite. However, a little attention has been paid to effects of the carbon nanomaterials' structural properties on the electrochemical performances of the enzyme-nanocomposites. This work aims at studying the effects of surface and bulk properties of carbon nanomaterials with different degrees of graphitization on the electrochemical performances of glucose oxidase (GOx)-nanocomposites produced by immobilizing GOx within a network of carbon nanopaticles. Two types of carbon nanomaterials were used: graphitized mesoporous carbon (GMC) and purified mesoporous carbon (PMC). Graphitization index, surface functional groups, hydrophobic properties, and rate of aggregation were measured for as-received and acid-treated GMC and PMC samples by using Raman spectrometry, X-ray photoelectron spectroscopy (XPS), contact angle measurement, and dynamic light scattering (DLS), respectively. In addition to these physical property characterizations, the enzyme loading and electrochemical performances of the GOx-nanocomposites were studied via elemental analysis and cyclic voltammetry tests, respectively. We also fabricated BFCs using our GOx-nanocomposite materials as the enzyme anodes, and tested their performances by obtaining current-voltage (IV) plots. Our findings suggest that the electrochemical performance of GOx-nanocomposite material is determined by the combined effects of graphitization index, electrical conductivity and surface chemistry of carbon nanomaterials.

This paper describes the manufacturing method and properties of a superalloy as a gas turbine blade material and a thermal barrier coating to protect it. The development process of superalloy and characteristics of each casting method were introduced. In particular, the single crystal superalloys were analyzed for creep and tensile properties with temperature according to chemical composition. In addition, the theories of creep life prediction models were summarized and comparative analysis was performed. Finally, the manufacturing processes of thermal barrier coatings were introduced, and the characteristics and effects of mechanical, thermal, and durability characteristics of each manufacturing process are described. We believe that this comprehensive review will help not only the gas turbine industry/community, but also material scientists, measurement physicists/engineers, and theorists interested in superalloys and high-temperature ceramics.

This study aimed to compare the risk of chronic periodontitis (CP) between participants who underwent tonsillectomy and those who did not (control participants) using a national cohort dataset. Patients who underwent tonsillectomy were selected from a total of 514,866 participants. A control group was included if participants had not undergone tonsillectomy from 2002 to 2015. The number of CP treatments was counted from the date of the tonsillectomy treatment. Patients who underwent tonsillectomy were matched 1:4 with control participants who were categorized based on age, sex, income, and region of residence. Finally, 1044 patients who underwent tonsillectomy were matched 1:4 with 4176 control participants. The adjusted estimated value of the number of post-index date (ID) CP did not reach statistical significance in any post-ID year (each of p > 0.05). In another subgroup analysis according to the number of pre- ID CP, it did not show statistical significance. This study revealed that tonsillectomy was not strongly associated with reducing the risk of CP. Even though the tonsils and periodontium are located adjacently, and tonsillectomy and CP may be related to bacterial inflammation, there was no significant risk of CP in patients undergoing tonsillectomy.