Scalable Procedure Research Articles

An efficient p‐multigrid spectral element model for fully nonlinear water waves and fixed bodies

AbstractIn marine offshore engineering, cost‐efficient simulation of unsteady water waves and their nonlinear interaction with bodies are important to address a broad range of engineering applications at increasing fidelity and scale. We consider a fully nonlinear potential flow (FNPF) model discretized using a Galerkin spectral element method to serve as a basis for handling both wave propagation and wave‐body interaction with high computational efficiency within a single modeling approach. We design and propose an efficient ‐scalable computational procedure based on geometric p‐multigrid for solving the Laplace problem in the numerical scheme. The fluid volume and the geometric features of complex bodies is represented accurately using high‐order polynomial basis functions and unstructured meshes with curvilinear prism elements. The new p‐multigrid spectral element model can take advantage of the high‐order polynomial basis and thereby avoid generating a hierarchy of geometric meshes with changing number of elements as required in geometric h‐multigrid approaches. We provide numerical benchmarks for the algorithmic and numerical efficiency of the iterative geometric p‐multigrid solver. Results of numerical experiments are presented for wave propagation and for wave‐body interaction in an advanced case for focusing design waves interacting with a floating production storage and offloading. Our study shows, that the use of iterative geometric p‐multigrid methods for the Laplace problem can significantly improve run‐time efficiency of FNPF simulators.

Demonstration of Phase Change Thermal Energy Storage in Zinc Oxide Microencapsulated Sodium Nitrate

Microencapsulation of sodium nitrate (NaNO3) as phase change material for high temperature thermal energy storage aims to reduce costs related to metal corrosion in storage tanks. The goal of this work was to test in a prototype thermal energy storage tank (16.7 L internal volume) the thermal properties of NaNO3 microencapsulated in zinc oxide shells, and estimate the potential of NaNO3–ZnO microcapsules for thermal storage applications. A fast and scalable microencapsulation procedure was developed, a flow calorimetry method was adapted, and a template document created to perform tank thermal transfer simulation by the finite element method (FEM) was set in Microsoft Excel. Differential scanning calorimetry (DSC) and transient plane source (TPS) methods were used to measure, in small samples, the temperature dependency of melting/solidification heat, specific heat, and thermal conductivity of the NaNO3–ZnO microcapsules. Scanning electron microscopy (SEM) and chemical analysis demonstrated the stability of microcapsules over multiple tank charge–discharge cycles. The energy stored as latent heat is available for a temperature interval from 303 to 285 °C, corresponding to onset–offset for NaNO3 solidification. Charge–self-discharge experiments on the pilot tank showed that the amount of thermal energy stored in this interval largely corresponds to the NaNO3 content of the microcapsules; the high temperature energy density of microcapsules is estimated in the range from 145 to 179 MJ/m3. Comparison between real tank experiments and FEM simulations demonstrated that DSC and TPS laboratory measurements on microcapsule thermal properties may reliably be used to design applications for thermal energy storage.

Use of heart rate variability to predict hospital length of stay for COVID-19 patients: A prospective observational study.

Background:As the COVID-19 pandemic continues, determining hospital demands has become a vital priority. Heart rate variability (HRV) has been linked to both the presence of viral infection and its severity. We investigate the possibility of using HRV parameters in comparison to other clinical parameters for predicting the hospital length of stay (LOS) for COVID-19 patients.Methods:This was a population-based cohort study. Measurements were performed in a specialized hospital for respiratory disease, dedicated to COVID-19. Patients were polymerase chain reaction positive for COVID-19 and on their 1st day of admission. Heart period, respiratory sinus arrhythmia (RSA), low frequency (LF) HRV, and vagal efficiency were calculated from electrocardiogram signals. This study investigated the correlation of HRV, demographic, and laboratory parameters with hospital LOS.Results:Forty-one participants were recruited, with a significant relationship, observed between hospital LOS and some demographic and clinical parameters such as lymphocyte count, age, and oxygen saturation of arterial blood. There was a negative relationship between LF and hospital LOS (r = −0.53, 95% confidence interval: −0.73, −0.24). Higher vagal efficiency predicted shorter hospital LOS in patients younger than 40 years of age (19.27% shorter hospital LOS was associated with a one SD higher value of VE, P = 0.007).Conclusion:HRV measurement is a non-invasive, inexpensive, and scalable procedure that produces several metrics, some of which are useful for predicting hospital LOS and managing treatment resources during COVID-19 pandemic.

Chemical and computational strategy for design of “switchable” sorbent based on hydroxyapatite nanoparticles for dispersive micro-solid phase extraction of tetracyclines

A challenging task in analytical chemistry is an application of renewable and natural materials for isolation of hazardous substances such as antimicrobial drugs from environmental samples. The energy-efficient scalable hydrothermal procedure to fabricate the eco-friendly “switchable” sorbent based on hydroxyapatite nanoparticles with in situ modified surface using a small amount of capping agents was developed. Sorbents characterization including the surface composition investigation via quantum-chemical calculation based on the original approach was provided. The sorbents demonstrated well expressed controllable surface switching and high values of the sorption and elution efficiency for tetracycline, oxytetracycline, and chlortetracycline achieved by simple change of the medium pH. These processes were thoroughly discussed based on the results of chemical and computational experiments. A simple and universal strategy for choosing a suitable sorbent for solid phase extraction of target analytes was proposed for the first time. It was shown that the developed eco-friendly sample preparation procedure with use of biocompatible sorbents could be applied both for removal of target analytes from sample matrix (water samples) as well as for the quantitative analytes determination after elution step. It is believed that the presented research is significant for the determination of different amphoteric analytes in wide variety of samples.

Polymer Stabilized Liquid Metal Nanodroplets As an Artificial Interphase Layer for Lithium Metal Anodes

Lithium (Li) metal batteries are considered to be the next-generation high energy density batteries because of the low reduction potential of metallic Li (−3.04 V) and its high specific capacity (3860 mA h g−1). However, there are challenges to implement lithium metal as an anode material. Especially the brittle and unstable solid electrolyte interface (SEI) formed by reaction of highly reactive lithium metal with liquid electrolytes, which can lead to low Coulombic efficiency and short cycle life.1 The design of an artificial SEI, i.e. ex-situ building of a protective layer on Li metal has shown to be effective for stabilizing Li metal anode and interphase. Especially, Li alloys can enable stable Li metal anodes by i) providing fast ion transport at the interphase, ii) suppressing the Li dendrites growth, iii) generating a stable interface between Li alloy anode and electrolyte, and iv) exhibiting high exchange currents, overall resulting in stable long-term performance.2 In 2017, Nazar et al. first reported a facile and scalable procedure to fabricate thin alloy layers onto Li metal foil via the in situ reduction of metal chlorides by Li.3 Two-metal component alloy and ternary alloy systems (based on Ga, Sn, In, Zn, Mg, Ag etc.) have also been investigated in Li-ion and alkali metal batteries. Goodenough et al. reported a lithium alloyed Ga-In nanoparticle/carbon/binder electrode. The liquid Ga-In system exhibited self-healing feature and high diffusivity in liquids, and the composite anode realized a high capacity and excellent stability in both Li-ion and Na-ion batteries.4 Herein, EGaIn consisting of 75 wt% Ga and 25 wt% In is chosen as a model liquid metal. An artificial SEI design based on poly(ethylene oxide)-block-poly(acrylic acid) (PEO-b-PAA) diblock copolymer was exploited to stabilize EGaIn nanodroplets. The attachment of polymer brushes onto EGaIn nanodroplets can greatly improve the dispersibility of nanoparticles, therefore creating a more uniform protection layer than bulk EGaIn. PAA chains are designed as anchoring blocks to attach onto the EGaIn “skin” layer via multiple coordination interactions, while PEO chains should ensure the ionic conductivity for Li ions transport. The molecular weight and molecular weight distribution of PAA can be precisely controlled by atom transfer radical polymerization (ATRP) (Figure 1a). Under ultrosonication, PEO-b-PAA act as polymeric surfactant to fabricate polymer-grafted-EGaIn nanodroplets through a “grafting onto” method via the PAA anchoring groups. This provides a general and robust strategy to achieve high colloidal stability and good dispersibility (Figure 1b). The artificial SEI was then fabricated on Cu current collector by spray coating, which is a facile strategy to form uniform and thin layers onto large surface area substrates. Galvanostatic Li electrodeposition voltage profiles for asymmetric Li cells (Cu|Li, Cu@EGaIn-PEO-b-PAA|Li) were conducted. The lower nucleation overpotentials on coated Cu compared to bare Cu illustrates that the EGaIn/PEO-b-PAA artificial SEI help Li to stably nucleate and uniformly grow the Li nuclei via interlayer gaps above and under the SEI. The artificial SEI regulate lithium deposition and enabes faster Li-ion transport and diffusion. In conclusion, polymer stabilized EGaIn nanodroplets used as artificial SEI can effectively protect Li metal anodes, further improving the capacity retention, Coulombic efficiency, and lifespan of Li metal batteries.Figure 1. a) Synthesis of PEO-b-PAA copolymer. b) Preparation of polymer stabilized EGaIn nanodroplets. c) Nucleation behavior of Li metal on artificial SEI modified Cu substrate. Figure 1

Carbon-Supported Trimetallic Catalysts (PdAuNi/C) for Borohydride Oxidation Reaction.

The synthesis of palladium-based trimetallic catalysts via a facile and scalable synthesis procedure was shown to yield highly promising materials for borohydride-based fuel cells, which are attractive for use in compact environments. This, thereby, provides a route to more environmentally friendly energy storage and generation systems. Carbon-supported trimetallic catalysts were herein prepared by three different routes: using a NaBH4-ethylene glycol complex (PdAuNi/CSBEG), a NaBH4-2-propanol complex (PdAuNi/CSBIPA), and a three-step route (PdAuNi/C3-step). Notably, PdAuNi/CSBIPA yielded highly dispersed trimetallic alloy particles, as determined by XRD, EDX, ICP-OES, XPS, and TEM. The activity of the catalysts for borohydride oxidation reaction was assessed by cyclic voltammetry and RDE-based procedures, with results referenced to a Pd/C catalyst. A number of exchanged electrons close to eight was obtained for PdAuNi/C3-step and PdAuNi/CSBIPA (7.4 and 7.1, respectively), while the others, PdAuNi/CSBEG and Pd/CSBIPA, presented lower values, 2.8 and 1.2, respectively. A direct borohydride-peroxide fuel cell employing PdAuNi/CSBIPA catalyst in the anode attained a power density of 47.5 mW cm−2 at room temperature, while the elevation of temperature to 75 °C led to an approximately four-fold increase in power density to 175 mW cm−2. Trimetallic catalysts prepared via this synthesis route have significant potential for future development.

Molecularly Imprinted Silver Nanocomposites for Explosive Taggant Sensing

Sensing explosive taggants such as 3-nitrotoluene (3-NT) and 2,3-dimethyl-2,3-dinitrobutane has become a strategic priority in homeland security. This work reports the synthesis of a solid-state plasmonic sensor based on a nanocomposite of Ag nanoparticles (NPs) embedded in a molecularly imprinted polymer (MIP) for selective detection of 3-NT, an explosive taggant for 2,4,6-trinitrotoluene. In our approach, the in situ synthesis of Ag NPs and the molecular imprinting with 3-NT as a template take place simultaneously inside the polyethyleneimine (PEI) thin film during the baking step after spin coating. The MIP sensor fabrication is done by a low-cost, fast, and scalable one-step procedure. We demonstrate the chemosensing capabilities of Ag-PEI MIP nanocomposites to 3-NT using the localized surface plasmon resonance band intensity decay as a sensing parameter. The molecular imprinting approach results in an enhancement of specific sensor response to 3-NT, with a limit of detection of 54.8 ng for 3-NT and a sensitivity of 24.0% ± 3.0%. We tested the MIP sensor specificity by comparing the sensor response to several NO2-containing molecules. The Ag-PEI MIP sensor demonstrated a robust, specific molecular recognition toward 3-NT. Because the MIP nanocomposite sensor is easy to prepare, easy to use, and inexpensive, these plasmonic sensors can be easily implemented with portable reading platforms into remote explosive detection and bomb disposal robots.

Bioanalysis of selinexor in mouse plasma micro-samples utilizing UPLC-MS/MS

Selinexor, a first-in-class inhibitor of the nuclear export protein Exportin-1 (XPO1), was recently approved for the treatment of multiple myeloma in combination with dexamethasone, and as monotherapy for diffuse large B-cell lymphoma. To enable investigations of selinexor in mice, we established and validated an ultrahigh-performance liquid chromatography – tandem mass spectrometry (UPLC-MS/MS) assay in the plasma concentration range of 1–1000 ng/mL using plasma microsamples of 5 µL. Protein depletion with acetonitrile was used for efficient isolation of selinexor which was followed by a dilution step, resulting in a scalable sample processing. Quantification was performed with positive electrospray ionization tandem mass spectrometry in the selected reaction monitoring mode. Due to the high sensitivity of the quantification and the scalable sample processing procedure, the assay can be used for different concentration ranges to either further decrease the achievable lower limit of quantification or to reduce the amount of plasma used. The assay showed interday and intraday accuracy of 89.0–109.0% with a corresponding precision ≤ 14.1%. Suitability for investigations of selinexor in small animal experiments was demonstrated by determination of plasma selinexor in mice after oral administration.

Bioactive Sugarcane Lipids in a Circular Economy Context.

Most of the global sugar and ethanol supply trade comes from the harvesting of Saccharum officinarum (i.e., sugarcane). Its industrial processing results in numerous by-products and waste streams, such as tops, straw, filter cake, molasses and bagasse. The recovery of lipids (i.e., octacosanol, phytosterols, long-chain aldehydes and triterpenoids) from these residues is an excellent starting point for the development of new products for various application fields, such as health and well-being, representing an important feature of the circular economy. By selecting green scalable extraction procedures, industry can reduce its environmental impact. Refluxed ethanol extraction methods have been demonstrated to meet these characteristics. On the other hand, effective non-solvent methodologies such as molecular distillation and supercritical CO2 extraction can fractionate lipids based on high temperature and pressure application with similar yields. Sugarcane lipophilic extracts are usually analyzed through gas chromatography (GC) and liquid chromatography (LC) techniques. In many cases, the identification of such compounds involves the development of high-temperature GC–MS/FID techniques. On the other hand, for the identification and quantification of thermolabile lipids, LC–MS techniques are suitable for the separation and identification of major lipid classes. Generically, its composition includes terpenes, phytosterols, tocopherol, free fatty acids, fatty alcohols, wax esters, triglycerides, diglycerides and monoglycerides. These compounds are already known for their interesting application in various fields such as pharma and cosmetics due to their anti-hypercholesterolemic, anti-hyperglycemic, antioxidant and anti-inflammatory properties.

Effect of morphology of C-rich silicon carbonitride ceramic on electrochemical properties of sulfur cathode for Li-S battery

Porous conducting materials represent a promising support for the immobilization of sulfur in the cathode of lithium–sulfur (Li-S) batteries. Herein, we provide an easy and scalable procedure for the preparation of such cathodes. This strategy consists of an infiltration of sulfur under solvothermal conditions at 155 °C into pores of carbon-rich silicon carbonitride (C-rich SiCN). Porous polymer-derived SiCN ceramics possess a unique combination of high electronic conductivity and robust, stress accommodating mechanical properties. The impact of the initial porosity and elemental composition of SiCN ceramics on the electrochemical performance of SiCN-S composites is addressed in this work. It is shown that material pyrolyzed at 1000 °C revealing a mesoporous character in line with the presence of a free carbon phase dispersed in SiCN demonstrates the best electrochemical stability and the highest capacity (more than 310 mAh/g over 40 cycles) at a high sulphur content of 66 wt.%.

Attempts to Diminish the Drawbacks of Polylactic Acid Designed for 3D/4D Printing Technology-Fused Deposition Modeling

In order to improve thermal behavior and dimensional strability of polylactic acid (PLA) designed both for 3D and 4D printing technology-fused deposition modeling (FDM) using a scalable procedure, the polymer was melt compounded with additives which control the morphology by crystallization and/or reinforcing. Using the formulations which provide polylactic acid (PLA) improved thermo-mechanical properties and desired dimensional stability, the new materials were shaped, on a laboratory line, as filaments for printing technology. The selected compounds were than scaled up on a 50 kg/h compounding line into granules which prove to have good shapability as filaments for printing technology (1.85 +/- 0.05 mm diameter, required ovality, good appearance and smooth surface) and performed properly at 3D printing. The obtained results proved that functional properties of PLA can be improved by various methods so that, depending on the reached performances, the new material can be converted through printing technology into items for performance applications. The novelty of the article is related to the fact that it identifies a modifying solution for controlling the morphology of a type of PLA designed for 3D printing that already has an advanced crystallinity.

Future habitat suitability for species under climate change – Lessons learned from the strawberry tree case study

Climate change is already a reality, and habitat loss is affecting relentlessly tree species distributions. The strawberry tree (Arbutus unedo L., Ericaceae) is a Mediterranean evergreen tree used in this article as a case study to evince its expected threatening situation in the upcoming age. This research work seeks to identify the bioclimatic and physiographic variables that have the most impact on the strawberry tree’s spatial distribution in Portugal, acquiring vital knowledge for the design of accurate conservation and afforestation plans for the use and conservation of strawberry tree, working as a guide under a climate change scenario. For that, twenty-one bioclimatic variables, two physiographic attributes (altitude and slope), and the Emberger Index (EI) were used together with 318 observations of strawberry trees, to build a scalable Bayesian procedure, based on machine learning techniques, aimed to assess the species’ future habitat evolution through three temporal scenarios: (i) Control Run (1960–1990); (ii) 2050 and (iii) 2070. The results indicate for 2050 a 30% loss of the humid sub-region and a 35% increase in the semi-arid sub-region towards the north. In 2070, it is expected a 2% recuperation for the sub-humid area, but an 8% loss of the humid sub-area. Under these extreme climate change conditions, it is anticipated an almost complete loss of habitat for the strawberry tree in the south of Portugal. The expected ecological evolvability may trigger future migration paths and new refuges’ settlement in the northern sub-region for the succeeding decades and suggesting after 2070 the possibility of habitat switch and species drifting.

Innovated scalable efficient inference for ultra-large graphical models

Statistical inference for ultra-large graphical models is important in network data analysis. We exploit the innovated scalable efficient estimation (Fan and Lv, 2016) as an initial estimate to develop a scalable inference procedure for graphical models. The effectiveness of the proposed method is theoretically and numerically demonstrated.

Chromatography-Independent Fractionation and Newly Identified Molecular Features of the Adzuki Bean (Vigna angularis Willd.) β-vignin Protein.

Adzuki seed β-vignin, a vicilin-like globulin, has proven to exert various health-promoting biological activities, notably in cardiovascular health. A simple scalable enrichment procedure of this protein for further nutritional and functional studies is crucial. In this study, a simplified chromatography-independent protein fractionation procedure has been optimized and described. The electrophoretic analysis showed a high degree of homogeneity of β-vignin isolate. Furthermore, the molecular features of the purified protein were investigated. The adzuki bean β-vignin was found to have a native size of 146 kDa, and the molecular weight determined was consistent with a trimeric structure. These were identified in two main polypeptide chains (masses of 56–54 kDa) that are glycosylated polypeptides with metal binding capacity, and one minor polypeptide chain with a mass 37 kDa, wherein these features are absent. The in vitro analysis showed a high degree of digestibility of the protein (92%) and potential anti-inflammatory capacity. The results lay the basis not only for further investigation of the health-promoting properties of the adzuki bean β-vignin protein, but also for a possible application as nutraceutical molecule.

Scalable Synthesis of Porous SiFe@C Composite with Excellent Lithium Storage.

Utilizing cost-effective raw materials to prepare high-performance silicon-based anode materials for lithium-ion batteries (LIBs) is both challenging and attractive. Herein, a porous SiFe@C (pSiFe@C) composite derived from low-cost ferrosilicon is prepared via a scalable three-step procedure, including ball milling, partial etching, and carbon layer coating. The pSiFe@C material integrates the advantages of the mesoporous structure, the partially retained FeSi2 conductive phase, and a uniform carbon layer (12-16 nm), which can substantially alleviate the huge volume expansion effect in the repeated lithium-ion insertion/extraction processes, effectively stabilizing the solid-electrolyte interphase (SEI) film and markedly enhancing the overall electronic conductivity of the material. Benefiting from the rational structure, the obtained pSiFe@C hybrid material delivers a reversible capacity of 1162.1 mAh g-1 after 200 cycles at 500 mA g-1 , with a higher initial coulombic efficiency of 82.30 %. In addition, it shows large discharge capacities of 803.1 and 600.0 mAh g-1 after 500 cycles at 2 and 4 A g-1 , respectively, manifesting an excellent electrochemical lithium storage. This work provides a good prospect for the commercial production of silicon-based anode materials for LIBs with a high lithium-storage capacity.

Two Dimensional Anion Exchange-Size Exclusion Chromatography Combined with Mathematical Modeling for Downstream Processing of Foot and Mouth Disease Vaccine

The production of high-quality purified virus particles in high quantities for vaccine preparation requires a scalable purification procedure in the downstream step. A purification scheme based on combined strong anion-exchange and size exclusion chromatography (2D-AEC-SEC) was developed for the production of non-structural protein-free foot and mouth disease vaccine, and the whole procedure was accomplished with 77.9% virus yield. Additionally, a mathematical modeling and a simulation approach based on a plate model of chromatography were developed and matched with the experimental chromatography data to improve prediction of retention behavior and save time in the development of the downstream scale-up method. The purified pooled virus fraction obtained from the final polishing step had a purity higher than 85% based on analytical size exclusion analysis. Moreover, more than 90.1% of residual DNA (rDNA) was removed from the purified vaccine. The analysis of purified virus particles by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), dynamic light scattering (DLS), high performance size exclusion chromatography (HP-SEC), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and transmission electron microscopy (TEM) provided clear evidence of purity and demonstrated that the final product is structurally spherical, intact particles qualified for formulation as a vaccine product.

Environmentally Benign Route for Scalable Preparation of 1-Imino-3-thioisoindolines-The Key Building Blocks for the Synthesis of Dithio- and Diamino-β-isoindigo Derivatives.

A one-step, gram-scale protocol for the preparation of 1-imino-3-thioisoindolines and a novel one-pot two-step methodology of the synthesis of dithio- or diamino-β-isoindigo derivatives starting from phthalonitriles and sodium hydrosulfide in an aprotic dipolar solvent have been developed. It was demonstrated that the electronic properties of the substituent(s) in the phthalonitrile core play a critical role in β-isoindigo synthesis resulting either in the selective formation of dithio- or diamino-β-isoindigo chromophores. The N-acylated 1-imino-3-thioisoindolines can be used for the direct, easily scalable, and chromatography-free procedure for the preparation of a new class of N,N'-diacylamino-β-isoindigoid compounds. Properties of the monomeric as well as J-aggregated forms of dithio- and diamino-β-isoindigo were probed by the absorption and fluorescence spectroscopies. It was demonstrated that the tetracyano-diamino-β-isoindigo 3f can form a J-aggregate that absorbs at 793 nm and fluoresces at 824 nm. This aggregate is stable in N,N-dimethylformamide solution; however, it slowly dissociates in tetrahydrofuran or under sonication conditions. Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations were employed to elucidate the electronic structures, spectroscopic properties, and aggregation of new dithio- and diamino-β-isoindigo derivatives.

Highly Concentrated, Conductive, Defect-free Graphene Ink for Screen-Printed Sensor Application

HighlightsUltrathin and defect-free graphene ink is prepared through a high-throughput fluid dynamics process, resulting in a high exfoliation yield (53.5%) and a high concentration (47.5 mg mL−1).A screen-printed graphene conductor exhibits a high electrical conductivity of 1.49 × 104 S m−1 and good mechanical flexibility.An electrochemical sodium ion sensor based on graphene ink exhibits an excellent potentiometric sensing performance in a mechanically bent state.Real-time monitoring of sodium ion concentration in sweat is demonstrated.Conductive inks based on graphene materials have received significant attention for the fabrication of a wide range of printed and flexible devices. However, the application of graphene fillers is limited by their restricted mass production and the low concentration of their suspensions. In this study, a highly concentrated and conductive ink based on defect-free graphene was developed by a scalable fluid dynamics process. A high shear exfoliation and mixing process enabled the production of graphene at a high concentration of 47.5 mg mL−1 for graphene ink. The screen-printed graphene conductor exhibits a high electrical conductivity of 1.49 × 104 S m−1 and maintains high conductivity under mechanical bending, compressing, and fatigue tests. Based on the as-prepared graphene ink, a printed electrochemical sodium ion (Na+) sensor that shows high potentiometric sensing performance was fabricated. Further, by integrating a wireless electronic module, a prototype Na+-sensing watch is demonstrated for the real-time monitoring of the sodium ion concentration in human sweat during the indoor exercise of a volunteer. The scalable and efficient procedure for the preparation of graphene ink presented in this work is very promising for the low-cost, reproducible, and large-scale printing of flexible and wearable electronic devices.

Emerging Hearing Assessment Technologies for Patient Care

Emerging Hearing Assessment Technologies for Patient Care

Low-temperature growth of graphene nanoplatelets by hot-wire chemical vapour deposition

With the increasing demand for large-area graphene due to its versatility, there is an imminent requirement for scalable, low-temperature, and high yield growth procedures. In this study, the fabrication of large-area graphene nanoplatelets directly grown on tungsten (W) nanoparticles coated c-Si and quartz substrates by hot-wire chemical vapour deposition was demonstrated. A large area of single and bilayer graphene grown over W adatoms via controlled argon (Ar) plasma treatment varied from 0.5 to 10 min. The finest quality of continuous graphene layer up to an area of 2.56 × 104 μm2 was prepared at the optimised condition of 1 min, and verified through transmission electron microscopy in conjunction with energy dispersive X-ray, atomic force microscopy, and Raman spectroscopy. The prepared thin film of the carbon layer has excellent optical transparency (> 70%) and lower sheet resistance up to 718.3 Ω/sq. A detailed growth mechanism is proposed for the nucleation of graphene nanoplatelets under the influence of Ar plasma treatment on W nanoparticles.