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The adsorption of locust bean gum (LBG) onto Northern Bleached Softwood Kraft (NBSK) pulp improved paper tensile and burst strength and lowered refining energy by strengthening inter-fibre bonding. Adsorption kinetics and isotherms were investigated to develop a fundamental understanding of the adsorption mechanism. The adsorption rate followed pseudo-second-order kinetics and the activation energy was 99.34 kJ·mol−1, suggesting chemisorption. The adsorption rate constant increased rapidly with temperature from 25 to 45 °C (k = 1.93 to 24.03 g·mg−1·min−1), but the amount adsorbed at equilibrium decreased (qe = 1.91 to 0.48 mg·g−1 o.d. fibre). LBG adsorption to NBSK at 25 °C was consistent with the Langmuir adsorption model for LBG n = 5.00, and the equilibrium constant Kf = 2.57 mg·g−1·(mg·L−1)−1/n at 25 °C. Favorable adsorption conditions for negatively charged LBG were identified: 25 °C for 10 min, low dosage level ( 150 r.p.m.), acidic or neutral conditions (pH 2–7) without salt addition. Graphic abstract

Hydrophobic substrates for surface-enhanced Raman scattering (SERS) of adsorbate species are of great interest in chemical analysis because they can concentrate the analyte molecules in a small area of the surface, thereby improving the SERS sensitivity. Here, we propose a general strategy to fabricate hydrophobic paper-based substrates for SERS applications. The paper substrates have been manufactured by inkjet printing of aqueous emulsions containing Ag and polystyrene (PS) colloidal nanoparticles. In a first stage, the SERS performance of the substrates was optimized by varying the relative amounts of polymer/metal colloidal nanoparticles, the number of printing layers, and the degree of hydrophobicity of the substrates, using crystal violet as a molecular probe, which is well known for its strong SERS activity. In these conditions, the strongest surface Raman enhancement was observed for the highest water contact angle (146°) achieved. The selected Ag/PS-coated paper substrates showed wide applicability for several analytes, but in this study, a detailed analysis is provided for the pesticide thiram as a proof of concept. Several samples spiked with thiram have been analyzed by SERS, giving a detection limit of 0.024 ppm thiram in mineral water and apple juice, while in apple peel, the detection limit achieved for the same pesticide was 600 ng/cm2. We suggest that this one-step fabrication method produces a hydrophobic coating whose nanoscale features improve the SERS performance of the paper substrates. published

In order to obtain a lignin-based adsorbent with low cost, simple operation and no further modification, a calcium lignin adsorbent was prepared from chemical mechanical pulping (CMP) waste liquor by directly calcification from lime. The calcium lignin was characterized by BET, SEM, TEM, FT-IR and solid-state NMR analyses. The results showed that the molecular structure of the calcium lignin particles did not change when compared to sodium lignin, the formation mechanism of calcium lignin was revealed. The initial COD and lignin contents of CMP waste liquid were 54858 mg/L and 24.39 g/L, the conversion rate of lignin can reach 71.36% when was deal with lime. Thus, most of the lignin resources in the waste liquid were recovered. The middle-stage wastewater (MSWW) of pulping and papermaking was dealt with calcium lignin, the COD removal rate was up to 85.83%. The adsorption isotherms and kinetics were well fitted by the Langmuir model and pseudo-second-order kinetic model, respectively. Lime was regenerated from the used calcium lignin with high-temperature calcination, the conversion rate of calcium ions can reach 83.56%. Overall, the calcium lignin prepared by the one-step method exhibited great potential for effectively removing COD from middle-stage wastewater.

This paper focused on the studying of adsorption properties of Fe3O4-waste paper activated carbon composites for the removal of methylene blue dyes from water. The various parameters were carried out for the adsorption test of the composites, namely; contact time, adsorbent dose, initial MB concentration, pH solution, and temperature. The adsorption of isotherm, thermodynamics and kinetic was used to determine the characteristics of methylene blue adsorption onto the prepared adsorbent. The result indicates that the optimum adsorption capacity has occurred at pH = 6 in water solution. The adsorption capacity increase as the temperature increase until at 315K (45oC). The Langmuir isotherm is more appropriate to be applied as the adsorption model with the maximum adsorption capacity (qm) value of 101 and 93 mg/g for KA HCl-Fe3O4 and KA-Fe3O4 composites, respectively. The value of adsorption thermodynamic parameters was positive for ΔH, negative for ΔGo and positive for ΔSo, meaning the process adsorptions were endothermic, feasibility and spontaneity and randomness, respectively. The pseudo-second-order model was appropriate to predict the kinetic models for methylene blue adsorption onto the composites. The obtained adsorbent composites possess high adsorption efficiency and rapid magnetic separation. They were a promising for practical wastewater treatment for dyes removal from water.

Process-monitoring laboratories in the pulp and paper industry generally use a combination of wet chemical analyses and physical measurements to certify the fitness of a production pulp for a specific end-use. These laboratory tests require time and the effort of trained personnel, limiting their utility for real-time process control. Here we show that Raman probes of unrefined cellulosic pulps, well-suited to the online measurement of in-process materials, can predict the quality attributes of manufactured papers. The accuracy of prediction improves when the covariance is modelled in a reduced measurement space selected by a data-driven, feature-selection technique referred to as a Template Oriented Genetic Algorithm (TOGA). TOGA, combined with discrete wavelet transform (DWT), isolates functional-group features that correlate best with mechanical properties paper derived from refined pulp. Paper makers refine market pulps to build sheet strength using a beating process that decreases freeness as it increases fibre-fibre bonding. Methods demonstrated here predict manufactured sheet properties obtainable after any specified degree of refining from the Raman spectrum of an unrefined pulp. This analysis capacity will enable both vendors of market pulp and makers of sheet paper to specify in advance the amount of beating required to produce a desired product, thereby saving cost and conserving resources.

Detecting microRNA (miRNA) biomarkers expression is of great significance for the diagnosis and treatment of lung cancer. Surface-enhanced Raman scattering (SERS) has achieved microRNA sensing for the diagnosis of primary liver cancers. In this work, we developed a SERS technology for the rapid detection of lung cancers-related miRNA (miR-196a) using bimetallic Au-Ag nanowire (AgNW@AuNPs) substrates coupled with the target hairpin DNA. The finite-difference time-domain simulation proved that a large number of “hot spots” were generated between the AgNW and AuNPs, which resulted in a huge enhancement of the signal of Raman reporters. Filter paper treated by hexadecenyl succinic anhydride hydrophobic and modified with AgNWs@AuNPs was used as capturing substrate. The detection limits of miR-196a in PBS and serum were as low as 96.58 aM and 130 aM, respectively. Studies on nonspecific sequence and single-base mismatch of miRNA demonstrated that SERS-based platform was highly selective, excellent uniform, and reproducible. Finally, the platform was used to show that the miR-196a expression in the serum of lung cancer patients was much higher than that in healthy people. The detection results indicated that the SERS platform had potential applications in cancer diagnosis and might be a viable alternative to the conventional miRNA detection method, the real-time polymerase chain reaction (RT-PCR) technology.

A classical result of K. L. Chung and W. Feller deals with the partial sums S k S_k arising in a fair coin-tossing game. If N n N_n is the number of “positive” terms among S 1 S_1 , S 2 S_2 , …, S n S_n then the quantity P ( N 2 n = 2 r ) P(N_{2n} = 2r) takes an elegant form. We lift the restriction on an even number of tosses and give a simple expression for P ( N 2 n + 1 = r ) P(N_{2n+1} = r) , r = 0 r = 0 , 1 1 , 2 2 , …, 2 n + 1 2n+1 . We get to this ansatz by adaptating the Feynman–Kac methodology.

There is a growing interest on recycling of waste fibres as an alternative to landfill disposal. The aim of the study was to investigate the durability and mechanical properties of waste paper–cement composite panels reinforced with varying kenaf fibre content (FC, 2–10%). The panels produced were evaluated for properties including modulus of rupture (MOR) and apparent modulus of elasticity (MOE). The resistance of the panels was tested in the field for both termite damage and fungi decay for a period of 24 weeks. Accelerated decay test was also performed on selected samples. The results showed that the mean MOR ranged from 3.17 MPa for samples with 10% FC to 4.84 MPa for samples with 8% FC. The mean MOE ranged from 248 MPa for samples with 10% FC to 1298.1 MPa for samples with 8% FC. Statistical analysis showed that the effect of the fibre content was significant on the properties evaluated (p

Rising concern about the use of non-permitted colourants, in common food items such as dals and green vegetables sold in Indian markets, have led to a demand for low-cost point-of-use chemical analysis tools. Conventional food-analysis techniques involving tedious sample preparation protocols are not suited for in-field applications. Surface Enhanced Raman Spectroscopy (SERS) is an analytical technique that is well-suited for point-of-use chemical analysis with molecular level detection capability, which can also serve as a quality assurance tool for businesses. Effective and rapid signal collection from a large-area sample within a field-setting using disposable, low-cost SERS substrates is a key challenge in implementing such a solution. Herein, we demonstrate the use of inkjet-printed thin films comprising of robust nanostructured-silver as flexible, paper-based SERS (P-SERS) swabs for the direct detection of Metanil Yellow (MY) from toor dal (yellow split pigeon peas) samples and Malachite Green (MG) from green peas and green chillies. The macroscopic uniformity of these thin-films in combination with a portable Raman spectrometer equipped with orbital raster scanning (ORS™) technology for signal collection results in an unprecedented precision (RSD ∼ 1.6%) upon characterizing samples saturated with Rhodamine-6G (R6G), a standard Raman probe. As several food-cleansing products have appeared in the marketplace, the adulterant removal efficacy of some commercially available ‘washes’ as well as products such as ‘ozoniser’, which was determined by SERS characterization of swabs before and after use, is also reported.

Minimally invasive devices to detect molecules in dermal interstitial fluid (ISF) are desirable for point-of-care diagnostic and monitoring applications. In this study, we developed a microneedle (MN) patch that collects ISF for on-patch biomarker analysis by surface-enhanced Raman scattering (SERS). The micrometer-scale MNs create micropores in the skin surface, through which microliter quantities of ISF are collected onto plasmonic paper on the patch backing. The plasmonic paper was prepared by immobilizing poly(styrenesulfonate) (PSS) coated gold nanorods (AuNRs) on a thin strip of filter paper using plasmonic calligraphy. Negatively charged PSS was used to bind positively charged rhodamine 6G (R6G), which served as a model compound, and thereby localize R6G on AuNR surface. R6G bound on the AuNR surface was detected and quantified by acquiring SERS spectra from the plasmonic paper MN patch. This approach was used to measure pharmacokinetic profiles of R6G in ISF and serum from rats in vivo. This proof-of-concept study indicates that a plasmonic paper MN patch has the potential to enable on-patch measurement of molecules in ISF for research and future medical applications.

Highlights • Numerical simulations of acoustophoresis in pulp flow is conducted. • Parametric study of fiber characteristics, pulp flow regimes and acoustic parameters are conducted. • A feasibility study of industrial acoustophoresis for pulp concentration is performed. • A potential concentration gain of 15% is obtained experimentally., In pulp and paper mills, mechanical processes such as screening and washing are commonly used to remove accumulated solid suspensions and concentrate the pulp. For environmental reasons and to optimize paper production, an emerging challenge is to develop alternative methods to concentrate paper pulp between 3 % and 6 % consistency for which the mixed pulp-water flow is complex. Among the proposed solutions in the literature, solutions based on acoustic levitation, also referred as acoustophoresis, of low-consistency pulp have been demonstrated as a potential solution for efficient pulp concentration and water recirculation. However, no sensitivity analysis on the ultrasound and physical parameters was proposed, limiting the extension to a realistic application. Thus, this paper presents a numerical modeling of acoustophoresis for pulp flow concentration in a pipe. For this purpose, the pulp flow is defined as a pseudo-homogenous fluid with a turbulent Low Re k- ∊ formalism, and the pulp particles are considered spherical and deflected by two acoustic forces, namely the acoustic radiation force and the Stokes drag force, both induced by an ultrasound wave generated along the walls of a circular pipe. The combined action of these two forces in the pulp flow enables to concentrate the particles at the center of the pipe. The influences of particle size and mechanical properties, fluid properties and ultrasound parameters are analyzed within a parametric study to optimize the particle deflection and the pulp concentration. The experimental feasibility of the industrial use of acoustophoresis for the concentration of paper pulp is demonstrated with a concentration gain up to 15 %.

Raman spectroscopy has been widely used to measure thermophysical properties of 2D materials. The local intense photon heating induces strong thermal nonequilibrium between optical and acoustic phonons. Both first principle calculations and recent indirect Raman measurements prove this phenomenon. To date, no direct measurement of the thermal nonequilibrium between optical and acoustic phonons has been reported. Here, this physical phenomenon is directly characterized for the first time through a novel approach combining both electrothermal and optothermal techniques. While the optical phonon temperature is determined from Raman wavenumber, the acoustic phonon temperature is precisely determined using high‐precision thermal conductivity and laser power absorption that are measured with negligible nonequilibrium among energy carriers. For graphene paper, the energy coupling factor between in‐plane optical and overall acoustic phonons is found at (1.59–3.10) × 1015 W m−3 K−1, agreeing well with the quantum mechanical modeling result of 4.1 × 1015 W m−3 K−1. Under ≈1 µm diameter laser heating, the optical phonon temperature rise is over 80% higher than that of the acoustic phonons. This observation points out the importance of subtracting optical–acoustic phonon thermal nonequilibrium in Raman‐based thermal characterization., The optical–acoustic phonon thermal nonequilibrium is first probed through novel electrothermal and optothermal techniques. For graphene paper, the optical‐acoustic phonon energy coupling factor is found at (1.59–3.10) × 1015 W m−3 K−1, agreeing well with theoretical predictions. Under ≈1 µm laser heating, the optical phonon temperature rise is over 80% higher than that of the acoustic phonons.

We studied the production and electrochemical performance of NiCo2S4 electrodeposited reduced graphene oxide (rGO) paper for use as a freestanding flexible electrode for the simultaneous determination of folic acid (FA) and ascorbic acid (AA). Production of rGO paper was achieved through vacuum filtration of the aqueous dispersion of graphene oxide, followed by chemical reduction in hydrogen iodide solution. NiCo2S4/rGO paper material was fabricated with a simple approach using electrodeposition of hydrothermal synthesized NiCo2S4 nanoparticles directly on rGO paper. The physicochemical properties of as-prepared flexible NiCo2S4/rGO paper were characterized by means of field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and X-ray powder diffraction patterns. This freestanding paper electrode demonstrated high sensitivity, a wide linear range, and a low detection limit towards the simultaneous detection of FA and AA. NiCo2S4/rGO paper sensor, possessing easy preparation, low cost, and high flexibility, was tested in real samples with promising recoveries. This study exhibited that the approach of the electrodeposition of bimetallic sulfides on freestanding graphene paper substrates has great potential to develop high-performance flexible electrochemical sensors.

Organic-rich pulp and paper mill sludge (PPMS) has the potential to become a renewable carbon source for producing alternatives to fossil-based product. In this work, PPMS treated by hydrothermal carbonization (HTC) was investigated based on its pyrolysis properties. The pyrolytic mechanism, kinetics data and product of the sample were studied using TG as well as pyrolysis tests in Py-GC/MS and a bench-scale reactor at 450, 550, and 650 °C. The results show that the thermal decomposition of feedstock is a two-stage reaction. The mean activation energy of the pyrolysis of HTC treated PPMS was estimated as 233.08 kJ/mol, which is higher than that of the pyrolysis of paper sludge reported before. The changes in enthalpies, entropies and Gibbs free energies from the reactants to the activated complex were estimated. The concentration of monocyclic aromatic hydrocarbons in the derived organic liquid fraction shows a positive correlation with the pyrolysis temperature. At 550 °C, the organic liquid fraction reached its highest yield at 13.7% with an oxygen level of 10.7 wt% and a higher heating value of 35.9 MJ/kg. The pyrolytic chars show that a molar ratio of O:C is less than 0.2, which shows potential for use as a carbon sink.

Graphene paper is a promising electrode material for use in flexible supercapacitors due to its good electronic conductivity and excellent mechanical characteristics. However, layers of graphene paper have a strong tendency to restack, resulting in a seriously reduced specific surface area and limited electrochemical performance. In this paper, restacked layers of graphene paper are reopened by a vacuum-assisted method, and carbon nanotubes (CNTs) are directly deposited on the enlarged space between the opened graphene layers. Consequently, an ordered carbon composite structure with alternately arranged graphene sheets and CNTs is constructed and exhibits increased specific surface area and a 3D conductive network. The structure and morphology of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy and N2 adsorption/desorption measurements. The electrochemical performance was tested by galvanostatic charge-discharge test (GDC), electrochemical impedance spectroscopy (EIS) and cyclic voltammograms (CV). The obtained graphene/CNT paper exhibits a remarkably improved capacity of 170.8 F g−1, which is nearly two times higher than that obtained for a regular graphene paper.

Methylene blue removal by adsorption method had been done in batch method using adsorbent of used paper powder. Adsorption parameters covering adsorbent doses, contact times, pH, adsorbate concentrations and adsorption isotherm as well as desorption study of the absorbed methylene blue were evaluated. The results showed the highest adsorption of methylene blue was obtained at an optimum adsorbent dose, for 30 min at pH > 9. The maximum adsorption capacity of 30.77 mg/g was obtained with Langmuir isotherm model. While the effective methylene blue desorption on the used paper powder adsorbent was obtained c.a. 0.27 mg/g at pH 1.

The issue of operation of submersible vortex flowmeters used in the systems of monitoring of circulating and waste waters of pulp and paper production is considered. It is shown that in the event of an error in the installation of these instruments, an additional error appears due to the angle between the axis of the flow body (TO) of the flowmeter and the axis of the pipeline. This error is related to the measurement method, which in turn leads to a change in the Strouhal number (Sh). The influence of this error leads to a change in the geometry of the flow part of the submerged flowmeter (the appearance of the angle β), which in turn leads to a change in the vortex formation process. Variants of finding this error are considered, from which the method of numerical modeling of hydrodynamic processes with subsequent processing by the method of experiment planning was chosen. For each investigated velocity of the fiber suspension and the angle of deflection of the TO axis, a graph of the frequency spectrum of the vortex formation process was obtained. Which was later used to find the number Sh. The dependence of the installation error ΔSh,% is presented. in the form of a response surface. It is revealed that the error in the installation of the TO, which is estimated by the angle β, is relatively small and varies linearly with increasing β. If the angle β = ± 3 ° is accepted as an allowable value, then the error in measuring the flow rate of the suspension will not exceed 0.25% over the entire range of velocities under consideration., Рассматривается вопрос особенностей эксплуатации погружных вихревых расходомеров, применяемых в системах мониторинга оборотных и сточных вод целлюлозно-бумажного производства. Показано, что при ошибке монтажа данных приборов может появляться дополнительная погрешность, появляющаяся вследствие угла между осью тело обтекания (ТО) расходомера и осью трубопровода. Данная погрешность связана с методом измерения, которая в свою очередь ведет к изменению числа Струхаля (Sh). Влияние данной погрешности приводит к изменению геометрии проточной части погружного расходомера (появление угла β), что способствует изменению процесса вихреобразования. Рассмотрены варианты нахождения данной погрешности из которых был выбран метод численного моделирования гидродинамических процессов с последующей обработкой методом планирования эксперимента. Для каждой исследуемой скорости волокнистой суспензии и угле отклонения оси ТО был получен график частотного спектра процесса вихреобразования на ТО, который впоследствии использовался для нахождения числа Sh. Представлена зависимость погрешности монтажа ΔSh,% в виде поверхности отклика. Выявлено, что погрешность монтажа ТО, которая оценивается углом β, является относительно небольшой иизменяется сувеличением β линейно. Если принять в качестве допустимой величины угла β=±3°, то погрешность измерения расхода суспензии не будет превосходить 0,25% во всем диапазоне рассматриваемых скоростей.

Paper‐based sensors, microfluidic platforms, and electronics have attracted attention in the past couple of decades because they are flexible, can be recycled easily, environmentally friendly, and inexpensive. Here we report a paper‐based potentiometric sensor to detect the whole Zika virus with a minimum sensitivity of 0.26 nV/Zika and a minimum detectable signal (MDS) of 2.4x107 Zika. Our paper sensor works very similar to a P‐N junction where a junction is formed between two different regions with different electrochemical potentials on the paper. These two regions with slightly different ionic contents, ionic species and concentrations, produce a potential difference given by the Nernst equation. Our paper sensor consists of 2‐3 mm x 10 mm segments of paper with conducting silver paint contact patches on two ends. The paper is dipped in a buffer solution containing aptamers designed to bind to the capsid proteins on Zika. We then added the Zika (in its own buffer) to the region close to one of the silver‐paint contacts. The Zika virus (40 nm diameter with 43 kDa or 7.1x10‐20 gm weight) became immobilized in the paper’s pores and bonded with the resident aptamers creating a concentration gradient. Atomic force microscopy and Raman spectroscopy were carried out to verify that both the aptamer and Zika become immobilized in the paper. The potential measured between the two silver paint contacts reproducibly became more negative upon adding the Zika. We also showed that a Liquid Crystalline Display (LCD) powered by the sensor can be used to read the sensor output.

A graphene oxide paper (GOP) was irradiated with 500 keV proton for total fluence of 2 × 1013 cm−2 to 2 × 1015 cm−2 in a ground-based irradiation simulator. The spacing of layer, surface chemical composition, structural defects, thermal conductivity and electrical property of the GOP before and after irradiation was measured. The results indicated that the spacing of layer decreased after irradiation. The ratio of total carbon atom and total oxygen atom increased from 2.40 to 4.31 as well as the sp2 hybridized carbons obviously increased after 2 × 1015 cm−2 irradiation. The XPS analysis suggested the occurrence of reduction, and the Raman spectra indicated that the defects were produced after proton irradiation. Furthermore, the thermal conductivity of GOP decreased, and then increased smoothly as the irradiation fluences were increased, and the electrical property showed the similar trend. The change in the thermal and electrical properties for GOP could be attributed to the defects and the removal of oxygen-containing functional groups, which lead to the phonon conduct path and scattering centers changed under proton irradiation. This study could promote the application of GOP in future space expeditions.

We report on a corroborative study of the structural, morphological and electrical property alterations of free-standing graphene oxide (GO) papers subject to thermal reduction. Structural analysis performed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Raman techniques prove that the onset of major structural changes, characterized by removal of oxygen functionalities, occur in the 200–300 °C temperature range. The results are corroborated with related morphological changes observed using Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) imaging. Elemental analysis shows the GO paper reduced at 600 °C to contain an 85 wt. % carbon content and a remnant oxygen level of 13.31 wt. %. At the highest reduction temperatures, we see evidence of vacancy-type defects impeding the overall effectiveness of the reduction process. Detailed electrical resistance measurements and current–voltage (I-V) profiling conducted using four-point probe method reveals a several orders of magnitude drop in the sample resistance once the reduction temperature exceeds 200 °C, in good agreement with the structural and morphological changes. The fundamental insights revealed through these studies will be important for future applications where the electrical and mechanical properties of free-standing GO and reduced graphene oxide (rGO) are exploited in practical devices. Graphical abstract

We examine the trends in the studies published in international trade journals indexed in Web of Science (WoS) before and after the 2008 Global Financial Crisis (GFC). This study investigates the 5001 abstracts of trade articles starting from the post-millennium period by addressing issues in WoS database trade journals using the Latent Dirichlet Allocation (LDA) topic model. The purpose of the study is to evaluate whether topics and words differ that have been discussed in international trade literature before and after GFC. Mostly, contain topics differ when two periods are compared, although trade agreements and disputes, stock markets, and growth issues are frequently mentioned in both periods. In the post-crisis period, volatility, banks, and firm-specific issues are more popular. It is also among the findings that Asian economies gained importance after GFC. Generally, it has been revealed that the topics and titles in the trade literature can reflect current developments in international economics. Therefore, probably for next years, advances in technology as blockchain, emerging economies –especially China and India – and firm-based micro-scale papers will dominate the trade journals.

Paper based thermoresistive sensors are fabricated by rubbing WS2 powder against a piece of standard copier paper, like the way a pencil is used to write on paper. The abrasion between the layered material and the rough paper surface erodes the material, breaking the weak van der Waals interlayer bonds, yielding a film of interconnected platelets. The resistance of WS2 presents a strong temperature dependence, as expected for a semiconductor material in which charge transport is due to thermally activated carriers. This strong temperature dependence makes the paper supported WS2 devices extremely sensitive to small changes in temperature. This exquisite thermal sensitivity, and their fast response times to sudden temperature changes, is exploited thereby demonstrating the usability of a WS2-on-paper thermal sensor in a respiration monitoring device., 6 main text figures, 1 table, 6 supp. info. figures

This study explored the relationship between syntactic complexity and rhetorical functions and the relationship between syntactic complexity and level of move/step realization in learner-generated research paper introductions. We created a corpus of 79 introductions written by undergraduate L2 students at intermediate to high-intermediate levels. We annotated the introductions for moves and steps, measured their syntactic complexity at the global, clausal, and phrasal levels, and rated their level of move/step realization across four levels (no, low, intermediate, and high). We conducted one-way MANOVA, one-way ANOVA, Pearson correlation, and stepwise multiple linear regression analyses. We found sentences realizing Reviewing items of previous research function to be significantly longer than other steps in Move1 and to contain significantly more clausal and phrasal complexity features. Sentences performing Claiming centrality function also demonstrated significantly more phrasal complexity features as measured by complex nominals per clause. We also found a higher level of phrasal complexity in introductions with a higher level of move/step realization, which can be attributed to introductions including Step1 and Step3, rather than containing all steps. Our findings imply that there is value in developing explicit instructions on how to use complex structures in performing rhetorical steps in research paper introductions. © 2021 Elsevier Ltd

Estazolam (EST) is a common sedative-hypnotic drug with a risk of abuse. Therefore, rapid on-site detection of EST is necessary to control the abuse of EST. In this paper, a fast, simple, and sensitive method is demonstrated for the detection of EST in both water and beverages, using surface-enhanced Raman spectroscopy (SERS) techniques. Au@Ag core-shell nanoparticles (NPs) assembled on the filter paper as a SERS substrate exhibit good applicability and practicality. At the same time, density functional theory (DFT) is used to assign the vibration mode of the EST molecules, which can be used as a guide for subsequent experiments. The lowest detectable concentration of EST in aqueous solution can be as low as 5 mg/L, and signal uniformity is excellent (RSD687 = 5.56%, RSD1000 = 4.35%). In addition, EST components artificially added to orange juice and pomegranate juice can be effectively detected by simple pretreatment with a minimum detection concentration as low as 10 mg/L. Therefore, this study found that the use of Au@Ag core-shell nanoparticles paper-based SERS substrate provides a quick and easy method for the detection of illegally added drugs in beverages.

The coating technique, supposedly invented by Chinese papermakers no later than the 3rd century AD, greatly improved paper sheets’ qualities of color, texture, writability, and printability. Alongside the dispersal of papermaking and surface-treatment techniques beyond China, coated papers were manufactured and used in many other regions of the world. Understanding the manufacture of coated papers, therefore, is crucial for perceiving how surface treatments were developed to meet the need for paper with enhanced properties. However, the characterization of coating and coating pigments on ancient Chinese papers has long remained an unsolved issue, and previous studies on this topic have often produced inconclusive results. To explore a non-invasive methodology that can more reliably characterize coated papers and the coating pigment on them, this article presents the results of a pilot study that applied micro-computed tomography (micro-CT) and Raman spectroscopy to samples of three Qing Dynasty (1644–1911 AD) papers and two handmade papers manufactured in China in the 1990s. Micro-CT revealed the coating layer(s) on Lajian (waxed coated paper) and Lengjinjian (gold-dusted paper) of the Qing Dynasty and characterized the modern raw xuan and bamboo papers as uncoated. Raman spectroscopy, together with handheld X-ray fluorescence analysis, identified the mineral-based pigment in the coating layer, suggesting the use of lead white or kaolin as the coating pigment. Additionally, Raman analysis confirmed the use of other mineral pigments (red lead and cinnabar), beeswax, and organic dyes (gamboge, kermesic acid, and possibly purpurin) in the manufacture of Lajian and Lengjinjian papers. The combination of micro-CT and Raman spectroscopy, it is therefore suggested, is a practical, more reliable approach for non-invasive investigation of coating and coating pigments on ancient Chinese paper specimens.

We fabricate paper-supported semiconducting devices by rubbing a layered molybdenum disulfide (MoS2) crystal onto a piece of paper, similarly to the action of drawing/writing with a pencil on paper. We show that the abrasion between the MoS2 crystal and the paper substrate efficiently exfoliates the crystals, breaking the weak van der Waals interlayer bonds and leading to the deposition of a film of interconnected MoS2 platelets. Employing this simple method, that can be easily extended to other 2D materials, we fabricate MoS2-on-paper broadband photodectectors with spectral sensitivity from the ultraviolet (UV) to the near-infrared (NIR). We also used these paper-based photodetectors to acquire pictures of objects by mounting the photodetectors in a homebuilt single-pixel camera setup., Comment: 6 main text figures + 4 Supp Info figures

In this paper, a method of aging diagnosis under different oil-paper ratios is proposed by investigating the accelerated thermal aging data with different oil-paper ratios. Aged oil-paper insulation samples with oil-paper ratios of 10:1, 15:1 and 20:1 are obtained by accelerated thermal aging tests. The Raman spectra of the transformer oil samples are measured by a Raman spectrometer, and screened by random forest algorithm to extract the features. A modified model is established to correcting the features of the aged oil samples under the conditions of 15:1 and 20:1 oil-paper ratio to features under the condition of 10:1 oil-paper ratio. An grid search optimized support vector machine (SVM) classification model is established, and verified by the corrected features. The experimental results show that the proposed method can effectively identify the aging of oil-paper insulation with different oil-paper ratios.

A colorimetric paper-based enzyme-coupled antimony tin oxide nanoparticle (ATONP) nanobiosensor for selective detection of Cd2+ ions in clams and mussels is presented. Alkaline phosphatase (ALP) was immobilized on ATONPs via 16-phosphonohexadecanoic acid (16-PHA) to develop ATONP-ALP nanobiosensor. The biosensor was characterized using XPS, Raman spectroscopy, SEM, and EDX. ATONP-ALP nanobiosensor exhibited high selectivity towards detection of Cd2+ ion with a LOD 0.006 μg L−1 and linear range of detection 0.005–1 μg L−1. The developed biosensor was further integrated into a low-cost paper-based format. A visual color change was obtained for Cd2+ ion in the range 0.1–10 μg L−1. The developed biosensor was successfully demonstrated for the analysis of Cd2+ ions in clams with recoveries 101–104%. The ATONP-ALP nanobiosensor was validated using mussel tissue (BCR-668) and the conventional ICP-OES and ICP-MS techniques.

It is well-known that Einstein’s first attempt to explain E = mc2 which was published in Annalen der Physik in 1905, has been criticized as problematic. In particular, it has been shown by Ives and reiterated by Jammer that it suffers from the error of circular reasoning. Attempts have been made in the scientific literature to discount the circular reasoning objection of Ives, Jammer, Arzelies and others. Fritz Rohrlich in 1990 gave a remarkably simple and concise derivation of E = mc2 along lines similar to Einstein’s but based on both momentum and energy conservation, in contrast to Einstein’s which uses only energy considerations. Rohrlich’s approach using momentum conservation is an alternative to Einstein’s, which is free from objection in logical error, and we make it quite clear on the importance of the implicit assumption of momentum conservation in any attempt to refute the circular reasoning error in Einstein’s paper. It is our contention that this point is overlooked or altogether avoided by those who have attempted to uproot the circular reasoning criticism of Einstein’s paper.

In this work, the commercial carbon paper was firstly peeled in K2CO3 solution and then was further treated in a KNO3 solution to form functional exfoliation graphene (FEG) on the commercial carbon paper. The FEG/carbon paper was characterized by Raman spectra and scanning electron microscopy, confirming that some typical layered fold graphenes were successfully peeled off and stood on the carbon paper matrix. Then, Fe3O4 nanoparticles (NPs) were grown on the surface of FEG/carbon paper and the as-prepared Fe3O4 NPs/FEG/carbon paper was directly used as supercapacitor electrode. The specific capacitance of Fe3O4 NPs/FEG/carbon paper was about 316.07 F g−1 at a current density of 1 A g−1. Furthermore, the FEG/carbon papers were also functionalized by benzene carboxylic acid to form FFEG/carbon papers, and then the Fe3O4 NPs were grown on the surface of FFEG/carbon paper. The specific capacitance of Fe3O4 NPs/FFEG/carbon paper was 470 F g−1 at a current density of 1 A g−1, superior to some previous reported results. This work might provide a new strategy to prepare various nanostructures on FFEG/carbon papers for future applications.

Nanoparticle (NP)-loaded filter paper (FP)-based surface-enhanced Raman scattering (SERS) substrates have been prepared using differently shaped gold (Au) NPs. The shape of Au NPs plays a significant role in the amplification of SERS signal. Here, two differently shaped Au NPs were synthesized using two different techniques: (a) femtosecond (fs) laser ablation in liquid and (b) chemical method. Spherical shaped Au NPs were obtained using fs ablation of a bulk Au target in distilled water and Au nanostars (NSs) were achieved through chemical process utilizing N-vinyl-2-pyrrolidone as a reducing/capping agent. The size and shapes of these synthesized NPs and NSs were investigated meticulously using different characterization techniques such as transmission electron microscopy, field emission scanning electron microscopy and X-ray diffraction. Both the NPs and NSs were subsequently loaded onto commercially available FP by simple drop casting method. To achieve higher number of hot spots, the aggregated spherical NPs were obtained by addition of NaCl. The non-aggregated spherical, aggregated spherical, and star Au NPs loaded on FP were used for the detection of a dye (Nile blue) and an explosive molecule (Picric acid).

Laser-scribed electrochemical paper-based devices (LS-ePADs) are emerging as a greener alternative to conventional carbon electrochemical sensors since their fabrication does not involve the use of chemicals and the resulting devices show good reproducibility, scalability, and interesting electrochemical properties. This work evaluates the electrochemical properties of LS-ePADs using techniques such as cyclic voltammetry and electrochemical impedance spectroscopy (EIS), together with surface characterization by Raman spectroscopy and scanning electron microscopy. The voltammetric behavior of the porous electrode can be described as diffusional to the top electrode layer. Since the porous structure could affect the mass transport, EIS was used to prove that transport resistance is not limiting the charge transfer process in the electrode response. The graphene-based material that forms the electrode surface, identified by Raman spectroscopy, allows a considerably fast electron transfer between the LS-ePADs and the ferri/ferrocyanide molecules.

Raman spectroscopy, with its specific ability to generate a unique fingerprint‐like spectrum of certain substances, has attracted much attention in diagnosing the ageing degree of oil–paper insulation. In this study, the feature extraction and ageing diagnosis methods of oil–paper insulation Raman spectroscopy data are further studied. Based on the non‐linear analysis of Raman spectra of different ageing samples, kernel principal component analysis was applied to extract the spectral features, and the back‐propagation neural network was used to build a diagnosis model with high diagnostic accuracy. The results show that Raman spectroscopy combined with kernel principal component analysis and the back‐propagation neural network can diagnose the ageing state of oil–paper insulation, with a diagnostic accuracy of 91.43% (64/70). The proposed method provides an effective and feasible method for the ageing assessment of oil‐immersed electrical equipment.

In this work, the extended Debye model or Fourier transform is adopted to convert the polarization and depolarization current test results from the time domain into the frequency domain at low frequencies, thereby shortening the test time but producing large errors when the oil-paper insulation exhibits nonlinear characteristics. The voltage-current response characteristics of samples with three different moisture contents are tested to study the influence of moisture on the nonlinear characteristics. Hammerstein-Wiener (H-W) equivalent mathematical model is proposed for time-frequency domain conversion, and the results from this model and two formal methods are compared. The findings show that the errors of the two conventional methods increase with nonlinearity. The H-W model accurately depicts the nonlinear dielectric response of oil-paper insulation and thus can provide high-precision time-frequency domain conversion data.

Diagnosis of the aging stage of oil-paper insulation is an important technical means for preventing aging failure of oil-paper insulation equipment. This article proposes a Raman spectroscopy diagnostic model to assess the aging status of transformer oilpaper insulation by analyzing the Raman spectra of the insulating oil. Oil-paper samples in different aging stages were obtained from electrical and thermal accelerated aging tests in the lab. The Raman spectra of insulating oil were collected in the range from 400 to 3000 cm−1, which covers the Raman signals of the aging products of oilpaper insulation. Spectral peak contour features were extracted based on Voigt fitting of the Raman spectra and studied using the grid search optimized one-against-one multi-class support vector machine (OAO MCSVM) for diagnosis of the aging stage. The results show that the diagnostic accuracy of the diagnostic model based on the spectral peak contour features was 92% (46/50). Spectral peak contour features demonstrate an ability to reflect the aging process, and the proposed diagnostic method shows potential for monitoring oil-paper insulation.

Graphene has recently attracted great attention as a heat spreading material due to its unique thermal transfer property. Structural defects introduced into graphene unavoidably during graphene growth or processing are significantly affect its thermal transfer property. In this study, we choose four aromatic molecules (naphthalene, anthracene, tetracene and perylene) as “molecular patches” to heal structural defects in graphene, and free-standing paper-like heat spreading films based on graphene oxide (GO)-aromatic molecule composites have been fabricated via a synchronous reduction and assembly procedure, showing tunable optical transmittance and low sheet resistance. The Raman and X-ray diffraction characterizations of the as-prepared films indicate that the aromatic molecules have been adsorbed successfully by the GO and have partially restored the intrinsic quality of graphene. Preliminary studies on heat spreading materials using GO-aromatic molecule composite films demonstrate that the films can lead to obvious reduction in temperature of the hot source, indicating that these films are promising heat spreading materials for commercial portable electronics.

The question of the use of vortex flowmeters with different versions of the flow body (TO) under operating conditions on the technological lines of pulp and paper production is considered. It is shown that when using different TO in vortex flowmeters, an error occurs in the working range of speeds (flow rates). The observed error arises due to a change in the Strouhal number (Sh) and is associated with the measurement method. In this case, the Strouhal number begins to depend not only on the TO used as a vortex generator, but also on the flow velocity and the concentration of the fibrous suspension. As the main comparative factor for the investigated TOs, the force action on the sensitive element (flexible electrode) located inside the TO was taken. The study was carried out in several stages using numerical modeling and experimental design method. According to the results of a numerical study, the dependence of the Strouhal number (Sh) on the flow rate (V) and the concentration of the suspension (c) is presented. In a comparative analysis of the deviation of the Strouhal number from the average values, it was revealed that MOT No. 1 has a minimal effect on the concentration of the suspension in the working range of flow rates (± 0.5%). This circumstance makes it possible to verify and test flow meters with such maintenance in conventional pouring installations. The analysis of the maintenance with respect to the signal-to-noise ratio shows that the purest signal is generated by the cylindrical maintenance (maintenance No. 3), and maintenance No. 2 and No. 1 have noticeably large noise. The differences are explained by the absence on the surface of a cylindrical TO of extra protrusions, faces, which leads to a smoother flow of a suspension around its surface, as well as to a decrease in internal spurious noise.

Photographs are taken as valid evidences in various scenarios of our day to day life. Because of the developments in the field of Image Processing, altering images according to ones need is not a difficult task. Techniques of Image Forensics play its crucial role at this juncture. One of the mostly found types of image tampering is Copy-Move forgery. A copy-move forgery is performed by copying a region in an image and pasting it on another region in the same image, mostly after some form of post-processing like rotation, scaling, blurring, noise addition, JPEG compression etc. Two types of copy-move forgery detection techniques exist in literature. They are the Block based methods and Key-point based methods. Both the methods have their own advantages and limitations. This paper presents a survey on the recent developments in block based methods. As forgeries have become popular, the importance of forgery detection is much increased. Copy-move forgery, one of the most commonly used methods, copies a part of the image and pastes it into another part of the image. In this paper, we propose a detection method of copy-move forgery that localizes duplicated regions using Zernike moments. Since the magnitude of Zernike moments is algebraically invariant against rotation, the proposed method can detect a forged region even though it is rotated. Our scheme is also resilient to the intentional distortions such as additive white Gaussian noise, JPEG compression, and blurring. Experimental results demonstrate that the proposed scheme is appropriate to identify the forged region by copy-rotate-move forgery.

Drying experiments of two paper mill sludge were carried using hot air with a temperature range of 50?C - 80?C and an air velocity of 0.96 m/son a laboratory convective dryer. The drying characteristics were discussed and the drying kinetic equation was solved. The dependence of the reaction rate constant on the drying temperature was given by Arrhenius equation, and the activation energies for moisture diffusion in paper mill sludge sample A and B were found to be 21.53 kJ/mol and 15.38 kJ/mol, respectively.

While surface-enhanced Raman scattering (SERS) is a useful technique for the rapid and sensitive detection of biochemical compounds, conventional SERS chips suffer from high cost, complicated fabrication, inefficient sample collection processes and being not biocompatible. Here, we developed a facile, low-cost and highly sensitive gold nanostar (AuNS) immobilized paper-based SERS substrate that can be easily prepared in any laboratory. We performed studies on the paper materials, immobilization strategies, and SERS acquisition conditions to optimize the SERS enhancement and demonstrated that an optimized SERS signal was obtained from a dry substrate and wet analyte configuration suitable for rapid point-of-care detection. Using crystal violet (CV) as the Raman probe molecule, the optimized SERS substrate was prepared by having multiple drops of ∼100 pM of sodium citrate-treated colloidal AuNS on common laboratory filter paper before acquiring SERS spectra of CV freshly dripped onto the pre-dried AuNS-filter paper substrate. The optimized AuNS-filter paper substrate exhibited a SERS enhancement factor higher than that of two commercial Au/Ag-based SERS chips, with a detection limit of 1 nM CV and a SERS enhancement factor of up to 1.2 × 107. Such an optimized dry substrate and wet analyte configuration meant that the paper-based SERS substrate could be stored before use and Raman acquisition could be performed immediately without the need for the sample to dry. This makes the AuNS-filter paper substrate a simple and low-cost tool for trace level detection of biochemical species in a rapid, sensitive and non-destructive manner.

This paper reports the temperature-dependence of methanol generation and the tensile index under ageing conditions for two paper/oil systems: one consisting of a standard wood Kraft paper and the other of a thermally-upgraded Kraft paper (TUK). A linear correlation between methanol and the tensile index for these paper/oil systems was observed in a previous study at 170 °C. In the current study, the correlation was extended to a large range of temperatures (150–190 °C). The experimental data were fitted with a modified Calvini’s kinetic model, while the Arrhenius equation was used to model the kinetic of changes of the paper’s mechanical properties during ageing. Good agreement with the temperature (lnk vs. 1/T) was observed for the rate constants of the chain-end group production, methanol formation, and the decrease of mechanical properties. The Arrhenius equation applied to this data grouping showed activation energy of 130 ± 29 kJ/mol for the decrease in mechanical strength of the standard Kraft paper, while the value was 118 ± 55 kJ/mol for the TUK paper. These values are of the same order of magnitude as those obtained in this study and in the literature for the depolymerization of cellulose and the generation of methanol that was reported. This confirmed the close relationship between cellulose depolymerization, methanol generation and the reduction of the paper’s mechanical strength during ageing, dominated by the acid hydrolysis mechanism. The results, which can be seen as a benchmark and pave the way to further research, provide an opportunity for applying the proposed correlations to estimate the insulation condition in operating transformers.

In Lithium-air cathode, graphene containing materials have been reported as ideal cathode materials due to their large theoretical specific surface area, chemical stability, high electrical conductivity and charge capacity. In this study; three free-standing flexible graphene cathodes were produced with different thickness by vacuum filtration technique. For preparation of the graphene electrodes, graphene oxide (GO) papers were chemically reduced. Surface morphology of the produced graphene cathodes were characterized using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) was conducted to understand elemental composition of the GO paper. X-ray diffraction (XRD) technique and Raman spectroscopy were carried out to investigate the structure of the GO paper electrode. Moreover, specific surface area and porosity distribution of the GO paper was performed using Brunauer-Emmett-Teller (BET) method from N-2 adsorption and desorption isotherms and the pore size were calculated using the Barrett-Joyner-Halenda (BJH) algorithm on the desorption branch. Electrochemical performance of the freestanding graphene electrodes were assessed in ECC-Air test cell from 1.5 V to 4.5 V at a constant current density. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

We present a systematic study on the fabrication, characterization of versatile, and low-cost filter paper-based surface-enhanced Raman spectroscopy (SERS) substrates loaded with salt-induced aggregated Ag/Au nanoparticles (NPs). These were demonstrated as efficient SERS substrates for the detection of multiple explosive molecules such as picric acid (5 μM), 2,4-dinitrotoluene (1 μM), and 3-nitro-1,2,4-triazol-5-one (10 μM) along with a common dye molecule (methylene blue, 5 nM). The concentrations of the dye and explosive molecules in terms of mass represent 31.98 pg, 11.45 ng, 1.82 ng, and 13.06 ng, respectively. Silver (Ag) and gold (Au) colloidal NPs were prepared by femtosecond laser (∼50 fs, 800 nm, 1 kHz) ablation of Ag/Au-target immersed in distilled water. Subsequently, the aggregated nanoparticles were achieved by mixing the pure Ag and Au NPs with different concentrations of NaCl. These aggregated NPs were characterized by UV-visible absorption and high-resolution transmission electron microscopy techniques. The SERS substrates were prepared by soaking the filter paper in aggregated NPs. The morphologies of the paper substrates were investigated using field-emission scanning electron microscopy technique. We have achieved superior enhancements with high reproducibility and sensitivity for filter paper substrates loaded with Ag/Au NPs mixed for an optimum concentration of 50 mM NaCl.

A novel, simple, and inexpensive flexible surface-enhanced Raman-scattering (SERS) platform based on common laboratory filter paper modified with T i 3 C 2 T x flakes was reported. T i 3 C 2 T x synthesized from a T i 3 A l C 2 phase with a mixture of HCl and LiF and T i 3 C 2 T x nanosheets were characterized by the TEM, XRD, UV–Vis spectrum, and Raman spectrum. Paper-based substrate has been proven to sample on rough and irregular surfaces. Thus, T i 3 C 2 T x was further manufactured as paper substrate by the immersion method to transfer nanosheets to filter paper. SERS activity of prepared substrate was demonstrated using R6G by the same filter paper modified with and without T i 3 C 2 T x , and various concentrations of R6G were tested to prove the sensitivity of the substrates. Further detection of CV and MG certified the universality of paper substrate based on T i 3 C 2 T x nanosheets for detection of organic pollutants. The uniformity and stability were proved by CV and R6G molecules. This SERS platform combines the advantages of 2D material and flexible paper scaffolds, resulting in a highly sensitive, cost-efficient, and easy-to-manufacture large-scale flexible substrate and is expected to be used in practice.

Droplet impact and penetration into the paper-like medium are essential physical phenomena in variety of natural and industrial processes. The lattice Boltzmann model coupled with random-walk-based stochastic scheme is presented to calculate the interactions between inertial dominated droplet and fibrous medium. Results show that the droplet spreading regime is independent of surface wettability, volume fraction, and Ohnesorge number at very early impact stage. For fibrous medium with volume fraction ~ 50% and wettability 85°, three stages of penetration process are observed. Whereas for low-volume-fraction fibrous medium, the phases of droplet spreading and penetration are coupled which results in a small spreading width for hydrophilic wettability. It is found that the spaces of spreading width and penetration rate are divided by the curve of $$ Oh = 0.038 $$ and $$ Re = 144 $$ . The effects of Ohnesorge and Reynolds numbers largely influence the behaviors of droplet spreading and penetration process. The in-depth insight of inkjet droplet impact onto the paper-like fibrous medium is beneficial for improving printed products in Paper Electronics.

Paper-based analytical devices (PADs) have encountered a wealth of applications in recent years thanks to the numerous advantages of paper as a support. A silver nanoflower (AgNF) modified paper-based dual substrate for both surface-enhanced Raman spectroscopy (SERS) and ambient pressure paper spray mass spectrometry (PS-MS) was developed. AgNFs were immobilized on nylon-coated paper modified with silver and ethylenediamine. The developed substrate was characterized via scanning electron microscopy and infrared spectroscopy. The densely packed nanoscale petals of the AgNFs lead to a large number of so-called hot spots at their overlapping points, which result in an enhancement of the Raman signal. In addition, the presence of the AgNFs produces an increase in the sensitivity of the mass spectrometric analysis as compared with bare paper and nylon/Ag-coated paper. The dual substrate was evaluated for the identification and quantification of ketoprofen in aqueous standards as well as human saliva from healthy volunteers. The method enables the determination of ketoprofen with a limit of detection and limit of quantification via PS-MS of 0.023 and 0.076 mg L−1, respectively, with a relative standard deviation (RSD) of 3.4% at a concentration of 0.1 mg L−1. This dual substrate enables the simple and fast detection of ketoprofen with minimal sample preparation, providing complementary Raman and mass spectrometric information.

Porous carbon nanosheets were prepared by the carbonization of paper flower via chemical and physical activation. The structural properties of the as-prepared carbons were characterized using the techniques, such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, N2 sorption isotherms and X-ray photoelectron spectroscopy (XPS), while the related morphological analyses were conducted using scanning/transmission electron microscopy (SEM/TEM). The obtained carbons exhibit a high specific surface area up to 1801 m2 g−1 with a robust porous graphitic carbon layer structure, which provides the merits for potential application in energy storage and dye removal. We carried out potentiostatic and galvanostatic measurements using a three-electrode cell in 1.0 M H2SO4 aqueous electrolyte and achieved a specific capacitance of 118, 109.5, 101.7, 93.6, and 91.2 F g−1 at 1, 2, 4, 8 and 12 A g−1, respectively. The stability at 12 A g−1 was tested to reach 10,000 cycles with capacity retention of around 97.4%. We have demonstrated that the paper flower-derived carbons at activation temperature 800 °C (PFC-800) can be used as a promising electrode material in supercapacitor. PFC-800 can also serve as an efficient sunset yellow dye removal, showing the maximum adsorption capacity for sunset yellow (Q0, 273.6 mg g−1). Keywords: Porous carbon, Supercapacitor, Adsorption, Sunset yellow, Adsorption capacity

The effect of incorporating common dodecyl anionic and cationic surfactants such as dodecyltrimethylammonium bromide (DTAB), dodecylethyldimethylammonium bromide (DDAB), and sodium dodecylsulfate (SDS) in nanocomposites of reduced graphene oxide and nanocellulose are described. The stabilization and electrical properties of the nanocomoposites of reduced graphene oxide (RGO) and nanofibrillated kenaf cellulose (NFC) were characterized using four-point probe electrical conductivity measurements. Raman spectroscopy, field emission scanning electron microscopy, and high-resolution transmission electron microscopy were used to investigate dispersion morphology and the quality of RGO inside the NFC matrices. Small-angle neutron scattering (SANS) was used to study the aggregation behavior of the aqueous surfactant systems and RGO dispersions. The cationic surfactant DTAB proved to be the best choice for stabilization of RGO in NFC, giving enhanced electrical conductivity five orders of magnitude higher than the neat NFC. The results highlight the effects of hydrophilic surfactant moieties on the structure, stability and properties of RGO/NFC composites.

The separation and chemical analysis of mixtures in an emergency situation represent major challenges, especially in remote or poverty-stricken areas. A novel method was developed for the rapid separation and detection of multiple components via paper centrifugal chromatography, which costs as little as $2.26 US. The method was realized based on the combination of portable paper centrifugal chromatography and surface-enhanced Raman scattering (SERS) detection. This coupled technique was successfully implemented for the separation and qualitative analysis of a rhodamine 6G-crystal violet mixture and a colorless aniline-pyrocatechol-benzidine mixture. A chromatographic mobile phase was collected using absorbent cotton, which was demonstrated to have no effect on the SERS results. The optimized device achieved rapid and effective separation of the colorless aniline-pyrocatechol-benzidine mixture with a high centrifugal force (0.3303π2 N). The newly developed method involving multicomponent paper centrifugal chromatography-SERS detection will be of great value for emergency-related substance separation and analysis in remote and poor areas.

The intelligent task of semantically assigning a paper to a reviewer with respect to his knowledge domain remains a challenging task in academic conferences. From literature, a number of automated reviewer assignment systems have been presented which are based on distributional semantic models such as Term Frequency-Inverse Document Frequency (TF-IDF), Latent Semantic Indexing (LSI) and Latent Dirichlet Allocation (LDA) have been used to capture semantics. Thus, this study presents the comparative study of the three models based on their derived suitability scores between a paper meant for review and a reviewer’s representation papers. From the experimental results obtained, it shows that TF-IDF outperformed the accuracy level of the other two models by a substantial margin.