Search

Highly selective etching of silicon nitride (Si3N4) and silicon dioxide (SiO2) has received considerable attention from the semiconductor community owing to its precise patterning and cost efficiency. We investigated the etching selectivity of Si3N4 and SiO2 in an NF3/O2 radio-frequency glow discharge. The etch rate linearly depended on the source and bias powers, whereas the etch selectivity was affected by the power and ratio of the gas mixture. We found that the selectivity can be controlled by lowering the power with a suitable gas ratio, which affects the surface reaction during the etching process. X-ray photoelectron spectroscopy of the Si3N4 and QMS measurements support the effect of surface reaction on the selectivity change by surface oxidation and nitrogen reduction with the increasing flow of O2. We suggest that the creation of SiOxNy bonds on the surface by NO oxidation is the key mechanism to change the etch selectivity of Si3N4 over SiO2. [ABSTRACT FROM AUTHOR]

Objectives: To review the current literature related to the correlation between translaminar pressure difference (TLPD) and glaucoma. Materials and Methods: In this article, we conducted a literature review using MEDLINE via PubMed, Cochrane Eyes and Vision, and Google Scholar from 01/01/2010 to 31/12/2022. Search terms included "glaucoma", "intraocular pressure", "translaminar cribrosa pressure gradient/difference", "intracranial pressure", and "cerebrospinal fluid pressure". Of 471 results, 8 articles were selected for the meta-analysis. Results: Our meta-analysis demonstrated significantly higher intraocular pressure, lower cerebrospinal fluid pressure (CSFp), and greater TLPD in high-tension and normal-tension glaucoma groups compared to healthy groups. Conclusion: The differences in CSFp and TLPD between glaucoma and healthy people detected in current studies suggests a potential relationship between TLPD and glaucoma. [ABSTRACT FROM AUTHOR]

The last decade has witnessed an increasing interest in metamaterial absorbers (MMAs) because of their huge potential in a wide range of applications including energy harvesting, photodetectors, sensors, light modulators, infrared camouflage and wireless communication. Recently, machine learning (ML) has become one of the modern and powerful tools that can examine the design data in order to forecast the absorption behavior with much less effort and cost-effectiveness than conventional experimental and computation approaches. In this work, we utilize two ML algorithms, Polynomial Regression (PR) and Random Forest Regression (RFR), to predict the absorption strength and frequency of a symmetric disk-shape metamaterial structure operating within 10 and 16 GHz. The proposed models are trained on hundreds of simulation-generated samples. We show that fine-tuning some hyperparameters results in higher forecasting performance. The dependence of predicted results on input parameters demonstrates that PR has better performance in predicting absorption strength, while both algorithms share similar accuracy in predicting the absorption frequency. [ABSTRACT FROM AUTHOR]

Herein, we present for the first time a quick, easy, effective, and green method for preparing green nanofluids containing silver nanoparticles. The solution plasma method with a high-voltage DC power source and extracts from the Paramignya trimera was employed to prepare silver nanoparticles. The obtained results showed that silver nanoparticles were spherical, with a small average size of − 8 nm and fairly uniformly dispersed in solution. Surface plasmon resonance spectra show a strong peak at 410 nm for the prepared samples. The Fourier transform infrared spectra revealed the presence of possible functional groups on the surface of silver nanoparticles. Furthermore, the formation mechanism of silver nanoparticles is also proposed. The effect of the preparation times on the thermal conductivity of nanofluid was also investigated. As a result, the nanofluids prepared with longer preparation times had higher thermal conductivity and the highest improvement of 18.3% was obtained for the nanofluid using 4 min preparation compared to the base fluid. The obtained results indicate promise for a simple, fast, and environmentally friendly method for producing nanofluids containing silver nanoparticles with high thermal conductivity for potential applications. [ABSTRACT FROM AUTHOR]

In the present work, a new testing strategy was proposed to characterize the effect of a functional group on the interaction between rubber and filler in a rubber compound. In principle, the filler is mixed into a blend of rubber A and rubber B produced by functionalizing the rubber A with a specific chemical group. The phase-selective wetting of the filler is directly related to the effect of the functional group. Based on the new test approach, the impact of the non-rubber components in natural rubber (NR) and its epoxidation on the rubber-filler interaction in carbon black (CB) filled NR compounds was investigated. Accordingly, CB was mixed in three blends consisting of NR/isoprene (IR), deproteinized natural rubber (DPNR)/IR, and NR/epoxidized natural rubber (ENR). The phase selective wetting of CB was quantitatively characterized based on the wetting concept. It was found that proteins and epoxy groups did not affect the affinity between NR and CB, while the linked phospholipids interacted with the CB surface through cation-π bonding. By fitting the experimentally determined selective wetting of CB into the Z-model, the corrected surface tension of NR describing the effect of phospholipids was determined. The proposed test strategy was applied to other NR blends filled with silica and the hybrid CB/silica filler as reference fillers to demonstrate its transferability and verification. [ABSTRACT FROM AUTHOR]

To meet financial requirement for infrastructure development, the Public–Private Partnership (PPP) mechanism has been applied in a range of nations as a promising solution. However, unpredicted collapses that are linked to PPP applications have been experienced worldwide despite scientific protocols and concentrated efforts from engaged sectors. Numerous academic works have attempted to minimize PPP failures by exploring the area of risk management. However, there are limited efforts focusing on Southeast Asia. Previous studies in these markets have mainly identified risks, rather than in-depth analysis of root causes of failure, or proposing practical solution. This paper, by carrying out an evidence-based analysis of the Southeast Asia experience with an intensive focus on emerging markets, analyzes critical reasons and their underlying connections that result in PPP failure. Research outcomes also suggest using constructive strategies promoting a regulatory framework to diminish collapses that affect drivers and so enable the restoration of PPPs. [ABSTRACT FROM AUTHOR]

Human standing stability was evaluated using a swash plate drop device in a disturbance application. Under different experimental conditions using the device, electromyogram (EMG) measurements showed that the left and right lower limb muscles were used differently. It also demonstrated that the dynamics also differed depending on the experimental conditions. In particular, the dynamics of standing stabilization in a tandem standing position and a normal standing position significantly differed, and the activities of related muscles were also significantly different; this indicates that standing stability may potentially depend on the subjects. These results indicate the need for the comprehensive consideration of the standing and disturbance conditions during the quantitative evaluation of human standing stability. [ABSTRACT FROM AUTHOR]

For the first time, a systematic calculation of low-energy proton-nucleus elastic scattering off a series of doubly closed-shell nuclei is carried out. The direct and exchange elements of the Coulomb interaction between protons have been included to the residual interaction of the particle-vibration coupling (PVC). The nucleon-nucleon (NN) effective interaction of the Skyrme-type is consistently used in the whole process to generate the microscopic optical potential (MOP). Within the present microscopic optical potential model, angular distributions and analyzing power could be reproduced without any adjustable parameters. [ABSTRACT FROM AUTHOR]

Coal-fired power plant fly ash is a global environmental concern due to its small particle size, heavy metal content, and increased emissions. Although widely used in concrete, geopolymer, and fly ash brick production, a large amount of fly ash remains in storage sites or is used in landfills due to inadequate raw material quality, resulting in a waste of a recoverable resource. Therefore, the ongoing need is to develop new methods for recycling fly ash. The present review differentiates the physiochemical properties of fly ash from two coal combustion processes: fluidized bed combustion and pulverized coal combustion. It then discusses applications that can consume fly ash without strict chemical requirements, focusing on firing-associated methods. Finally, the challenges and opportunities of fly ash recycling are discussed. [ABSTRACT FROM AUTHOR]

Nanosilver solutions of colloidal silver nanoparticles at reasonable price, good quality, and availability are increasingly demanded for the application in agriculture and aquaculture for the prevention and treatment of diseases. In this paper, we have applied a new simple and environmental-friendly fabrication method based on a plasma electrochemical procedure, where silver nanoparticles are directly formed in the plasma environment from silver ions generated by the electrochemical process from the silver anode. The electrode dissolution rate, the formation percentage, and quality of the silver nanoparticles were examined and evaluated using atomic absorption spectroscopy, electrode mass change, transmission electron microscopy, and UV-Vis absorption spectroscopy. The silver nanoparticle formation was found of nearly 100% with the rate of about 3.3 mg per minute. Spherical nanoparticles are found in quite homogenous size distribution around about 9.7 nm in the solution. The solution of the plasma synthesized nanosilvers shows better antibacterial property in comparison to that of AgNO3 of the same molar concentration on both normal and antibiotics resistant E. coli strains. [ABSTRACT FROM AUTHOR]

We have designed an excellent visible-light-driven and high-performance photocatalyst with a Ag-Cu2O-ZnO nanowire heterostructure in our work by combining the hydrothermal approach with plasma–liquid technology. The structural and morphological characteristics and optical properties of the samples were evaluated using X-ray diffraction, field-emission scanning electron microscopy, and spectrophotometry, respectively. The results show that the Ag nanoparticles are mainly positioned on the Cu2O nanoclusters compared with the ZnO nanowire surface, forming broccoli-like Ag-Cu2O nanoclusters during the Ar gas plasma treatment process in an aqueous solution. The diameter of the Ag/Cu2O nanoclusters ranges from 150 to 180 nm. The Ag-Cu2O-ZnO nanowires exhibited improved photocatalytic performance, decomposing approximately 98% methyl orange dye in 30 min. This is a consequence of the synergistic interactions between the p-n heterojunction formed at the Cu2O-ZnO interfaces and the localized surface plasmon resonance (LSPR) effect of the Ag nanoparticles, which broaden the visible light absorption range and effectively separate the photogenerated charge carriers. [ABSTRACT FROM AUTHOR]

In this work, photocatalytic performance is divulged in the ternary CuO-Ag-ZnO nanowire synthesized via a two-step approach. The decoration of Ag and CuO nanostructures onto the surface of ZnO nanowires was simply carried out by using the plasma electrolytic oxidation method in a short time. The structure, size, morphology, and optical properties of as-prepared samples were characterized by X-ray diffraction, field-emission scanning electron microscopy, and spectrophotometry measurements. The diameters of Ag nanoparticles and ZnO nanoflowers are in the range of 5–20 nm and 20–60 nm, respectively. Within the first 15 min, methyl orange was decolorized 96.3 and 82.8% in the CuO-Ag-ZnO and Ag-ZnO, respectively, and there is only about 46.7% of that decomposed in pure ZnO. The CuO-Ag-ZnO shows a higher rate constant k = 0.2007 min−1 and a lower half-life time t = 6.1 min compared to Ag-ZnO and bare ZnO nanowires. The photo-reusability of the ternary nanostructures was estimated to be much outweighed compared to ZnO nanowires. Interestingly, the synergic incorporation between noble metal–semiconductor or semiconductor–semiconductor in the interfaces of Ag-CuO, Ag-ZnO, and CuO-ZnO expands the visible light absorption range and eliminates the photogenerated electron–hole recombination, resulting in a superior visible-light-driven photocatalyst. [ABSTRACT FROM AUTHOR]

A series of microporous Zn doped Fe3O4 spheres were successfully fabricated by a simple method. The characteristic of the obtained products was studied using the X-ray diffraction (XRD), Raman spectroscopy, (SEM) scanning electron microscopy, UV-vis reflectance, FTIR techniques. The photo-oxidation of As(III) to As(V) by as-synthesised samples under visible light was examined. The results exposed that with Zn doped Fe3O4 photocatalyst, the complete oxidation of As(III) to As(V) was observed, in which 1.05% mol of Zn doped into Fe3O4 showed the best photocatalytic performance. The proposed mechanism of photocatalytic activity enhancement was also investigated, indicating the introduction Zn content act as a trapping electron-centre resulting in the decreasing in the recombination rate of the photogenerated electron/hole pairs thus improving the photocatalytic performance. Photocatalytic tests were presented also in real groundwater and complete oxidation of As(III) to As(V) by 1.05 Zn doped Fe3O4 photocatalyst was achieved in 180 min under visible light irradiation. [ABSTRACT FROM AUTHOR]

Construction of hybrid three-dimensional (3D) hierarchical nanostructures via self-assembly of organic and inorganic compounds have recently attracted immense interest from scientists due to their unique properties and promise in a large range of applications. In this article, hybrid flower structures were successfully constructed by self-assembly an antibiotic, kanamycin, with Cu2+. The flower-like morphology was observed by scanning electron microscopy, to be approximately 4 µm in diameter and about 10 nm in thickness. FTIR spectroscopy and X-ray diffraction confirmed the antibiotic-inorganic hybrid structure was uniform composition, and showed crystallinity due to ordered self-assembly. The hybrid flowers showed high photocatalytic activity towards degradation of methyl blue during 240 minutes under visible light irradiation. A possible mechanism of photocatalytic activity was also proposed, that exposes the inherent advantages in using antibiotic-inorganic hybrid flowers as photocatalysts, where self-assembly can be used to generate active, high surface area structures for photodegradation of pollutants. [ABSTRACT FROM AUTHOR]

We report the facile synthesis of colloidal Si@Au and Si@Ag nanoparticles (NPs) through nanosecond IR laser plasma-mediated reduction of 0.03 mM aqueous solutions of chloroauric acid (HAuCl 4 ) and silver nitrate (AgNO 3 ) at different laser intensities on the surface of Si NPs during the ablation of the silicon wafer. The resulting hybrid colloidal NPs were analysed by UV–vis transmission spectroscopy, dynamic light scattering, scanning electron microscopy, energy-dispersive x-ray and x-ray photoelectron spectroscopy. [ABSTRACT FROM AUTHOR]

Caffeine (CaF), a widely consumed compound, has been associated with various harmful effects on human health, including metabolic, cardiovascular disease, and reproductive disorders. Moreover, it poses a signifincant threat to organisms and aquatic ecosystems, leading to water pollution concerns. Therefore, the removal of CaF from wastewater is crucial for mitigating water pollution and minimizing its detrimental impacts on both humans and the environment. In this study, a solar-driven Cu-doped graphitic carbon nitride (Cu/CN) photocatalyst was synthesized and evaluated for its effectiveness in oxidizing CaF in wastewater. The Cu/CN photocatalyst, with a low band gap energy of 2.58eV, exhibited superior performance in degrading CaF compared to pure graphitic carbon nitride (CN). Under solar light irradiation, CuCN achieved a remarkable CaF degradation efficiency of 98.7% CaF, surpassing CN's efficiency of 74.5% by 24.2%. The synthesized Cu/CN photocatalyst demonstrated excellent removal capability, achieving a removal rate of over 88% for CaF in wastewater. Moreover, the reusability test showed that Cu/CN could be successfully reused up to five cycles maintaining a high removal efficiency of 74% for CaF in the fifth cycle. Additionally, the study elucidated the oxidation mechanism of CaF using solar-driven Cu/CN photocatalyst and highlighted the environmental implications of the process. • Cu-doped g-C 3 N 4 (Cu/CN) significantly enhanced photodegradation of caffeine. • The degradation rate of caffeine (0.5 mg/L) by Cu/CN was 98.7%. • Cu/CN could remove over 88% caffeine from wastewater. [ABSTRACT FROM AUTHOR]

• Fast, facile, environmentally friendly method is proposed for preparing nanofluid. • Low cost, good stability, high thermal conductivity graphene oxide (GO) nanofluids was prepared. • Maximum enhancement in thermal conductivity of GO nanofluid reached up to 31%. • Interface layer thermal conductivity between GO and distilled water base was found. A simple, low-cost, and environmentally friendly approach was proposed for preparing high thermal conductivity nanofluids containing graphene oxide (GO) by using the solution plasma exfoliation (SPE) technique from graphite electrode of recycled battery core. The average length and thickness of GO were determined to be and 1.5 μm and 3.3 nm corresponding to 8–10 layers, respectively. The nanofluids containing 1 vol% GO exhibited a good stability and highest thermal conductivity of 0.786 W.m−1.K−1 which is about 31% enhancement in the thermal conductivity compared to the water-based fluid. The interfacial thermal resistance (R K) and the thermal conductivity interfacial layer (k i) between GO and base fluid were found to be 56 × 10−8 m2 K W−1 and 8.5 W m−1 K−1, respectively. [ABSTRACT FROM AUTHOR]